119 results on '"Brown KG"'
Search Results
2. Rockstar vs Ringmaster: Balancing Complementary Teaching Roles to Develop Management Skills
- Author
-
Brown, KG, Heslin, PA, Mortimore, G, Keating, LA, Brown, KG, Heslin, PA, Mortimore, G, and Keating, LA
- Abstract
Business school professors are under pressure. With students increasingly being viewed as customers who need to be “satisfied,” student evaluations are more and more consequential in determining contract renewal, tenure, and promotion decisions. Websites such as www.ratemyprofessors.com – enabling students to share unvarnished critiques of their instructors – up the ante. The proliferation of business school rankings taking account of “teaching quality” is creating a further institutional imperative for professors to strive to be stellar teachers, as well as top researchers. What are management instructors who want to improve their teaching to do?
- Published
- 2017
3. Daring to Be Different: Unconferences, New Conferences, and Reimagined Conferences
- Author
-
Billsberry,J, Kenworthy,AL, Hrivnak,GA, Brown,KG, Billsberry,J, Kenworthy,AL, Hrivnak,GA, and Brown,KG
- Published
- 2013
4. Using the National Land Cover Database as an indicator of shrub-steppe habitat: comparing two large United States federal lands with surrounding regions.
- Author
-
Burger J, Gochfeld M, Brown KG, Cortes M, Ng K, and Kosson D
- Abstract
There is a need to assess whether ecological resources are being protected on large, federal lands. The aim of this study was to present a methodology which consistently and transparently determines whether two large Department of Energy (U.S. DOE) facilities have protected valuable ecological lands on their sites compared to the surrounding region. The National Land Cover Database (2019) was used to examine the % shrub-scrub (shrub-steppe) and other habitats on the DOE's Hanford Site (HS, Washington) and on the Idaho National Laboratory (INL), compared to a 10-km and 30-km diameter band of land surrounding each site. On both sites, over 95% is in shrub-scrub or grassland, compared to the surrounding region. Approximately 70% of 10 km and 30-km bands around INL, and less than 50% of land surrounding HS is located in these two habitat types. INL has preserved a significantly higher % shrub/scrub habitat than HS, but INL allows grazing on 60% of its land. HS has preserved a significantly higher % grassland than INL but no grazing on site is present. The methodology presented may be used to compare key ecological habitat types such as grasslands, forest, and desert among sites in different parts of the country. This methodology enables managers, resource trustees, and the public to (1) make remediation decisions that protect resources, (2) assess whether landowners and managers have adequately characterized and protected environmental resources on their sites, and (3) whether landowners and managers have protected the integrity of that land as well as its climax vegetation.
- Published
- 2024
- Full Text
- View/download PDF
5. Development and Characterization of Hemoglobin Microbubbles for Acoustic Blood Oxygen Level Dependent Imaging.
- Author
-
Chaudhary S, Akter N, Pathour T, Kian Pour B, Rastegar G, Menon A, Brown KG, Fei B, Hwang M, and Sirsi SR
- Subjects
- Animals, Contrast Media chemistry, Acoustics, Mice, Phantoms, Imaging, Humans, Microbubbles, Oxygen chemistry, Oxygen blood, Hemoglobins chemistry, Ultrasonography methods
- Abstract
Oxygen levels in tissues and organs are crucial for their normal functioning, and approaches to monitor them non-invasively have wide biological and clinical applications. In this study, we developed a method of acoustically detecting oxygenation using contrast-enhanced ultrasound (CEUS) imaging. Our approach involved the use of specially designed hemoglobin-based microbubbles (HbMBs) that reversibly bind to oxygen and alter the state-dependent acoustic response. We confirmed that the bioactivity of hemoglobin remained intact after the microbubble shell was formed, and we did not observe any significant loss of heme. We conducted passive cavitation detection (PCD) experiments to confirm whether the acoustic properties of HbMBs vary based on the level of oxygen present. The experiments involved driving the HbMBs with a 1.1 MHz focused ultrasound transducer. Through the PCD data collected, we observed significant differences in the subharmonic and harmonic responses of the HbMBs when exposed to an oxygen-rich environment versus an oxygen-depleted one. We used a programmable ultrasound system to capture high-frame rate B mode videos of HbMBs in both oxy and deoxy conditions at the same time in a two-chambered flow phantom and observed that the mean pixel intensity of deoxygenated HbMB was greater than in the oxygenated state using B-mode imaging. Finally, we demonstrated that HbMBs can circulate in vivo and are detectable by a clinical ultrasound scanner. To summarize, our results indicate that CEUS imaging with HbMB has the potential to detect changes in tissue oxygenation and could be a valuable tool for clinical purposes in monitoring regional blood oxygen levels.
- Published
- 2024
- Full Text
- View/download PDF
6. Comparison of children and adults in deep brain stimulation for Tourette Syndrome: a large-scale multicenter study of 102 cases with long-term follow-up.
- Author
-
Gao Y, Wang S, Wang A, Fan S, Ge Y, Wang H, Gao D, Wang J, Mao Z, Zhao H, Zhang H, Shi L, Liu H, Zhu G, Yang A, Bai Y, Zhang X, Liu C, Wang Q, Li R, Liang K, Brown KG, Cui Z, Han C, Zhang J, and Meng F
- Subjects
- Humans, Male, Female, Child, Adult, Adolescent, Retrospective Studies, Follow-Up Studies, Young Adult, Treatment Outcome, Quality of Life, Middle Aged, Age Factors, Tourette Syndrome therapy, Deep Brain Stimulation methods
- Abstract
Background: Deep brain stimulation (DBS) is a promising therapy for refractory Gilles de la Tourette syndrome (GTS). However, its long-term efficacy, safety, and recommended surgical age remain controversial, requiring evidence to compare different age categories., Methods: This retrospective cohort study recruited 102 GTS patients who underwent DBS between October 2006 and April 2022 at two national centers. Patients were divided into two age categories: children (aged < 18 years; n = 34) and adults (aged ≥ 18 years; n = 68). The longitudinal outcomes as tic symptoms were assessed by the YGTSS, and the YBOCS, BDI, and GTS-QOL were evaluated for symptoms of obsessive-compulsive disorder (OCD), depression, and quality of life, respectively., Results: Overall, these included patients who finished a median 60-month follow-up, with no significant difference between children and adults (p = 0.44). Overall, the YGTSS total score showed significant postoperative improvements and further improved with time (improved 45.2%, 51.6%, 55.5%, 55.6%, 57.8%, 61.4% after 6, 12, 24, 36, 48, and ≥ 60 months of follow-up compared to baseline, respectively) in all included patients (all p < 0.05). A significantly higher improvement was revealed in children than adults at ≥ 60 months of follow-up in the YGTSS scores (70.1% vs 55.9%, p = 0.043), and the time to achieve 60% improvement was significantly shorter in the children group (median 6 months vs 12 months, p = 0.013). At the last follow-up, the mean improvements were 45.4%, 48.9%, and 55.9% and 40.3%, 45.4%, and 47.9% in YBOCS, BDI, and GTS-QOL scores for children and adults, respectively, which all significantly improved compared to baseline (all p < 0.05) but without significant differences between these two groups (all p > 0.05), and the children group received significantly higher improvement in GTS-QOL scores than adults (55.9% vs. 47.9%, p = 0.049)., Conclusions: DBS showed acceptable long-term efficacy and safety for both children and adults with GTS. Surgeries performed for patients younger than 18 years seemed to show acceptable long-term efficacy and safety and were not associated with increased risks of loss of benefit compared to patients older than 18 at the time of surgery. However, surgeries for children should also be performed cautiously to ensure their refractoriness and safety., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
7. Impact of the COVID-19 Pandemic on Functions of Nursing Professionals in the Care of Opioid Use Disorder: Systematic Review.
- Author
-
Brown KG, Chen CY, Dong D, Lake KJ, and Butelman ER
- Subjects
- Humans, Analgesics, Opioid therapeutic use, Opiate Substitution Treatment, SARS-CoV-2, United States epidemiology, COVID-19 nursing, COVID-19 epidemiology, Nurse's Role, Opioid-Related Disorders nursing, Opioid-Related Disorders epidemiology, Opioid-Related Disorders drug therapy, Pandemics
- Abstract
Background: Nursing professionals are vitally involved in the cascade of care for opioid use disorders (OUDs). The global spread of COVID-19 has had complex effects on public health aspects of major diseases, including OUDs. There are limited data on the major ways in which the COVID-19 pandemic has affected the functions of nursing professionals in the care of OUDs., Method: This systematic review followed Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines and examined published data for trends in OUD care during the first 2 years of the COVID-19 pandemic, focusing on nursing functions. The National Library of Medicine PubMed database and the EMBASE database were examined for peer-reviewed studies with primary data published between January 1, 2020, and December 31, 2021., Review Findings and Conclusions: Rapid changes were observed in numerous aspects of OUDs during the early pandemic stage, as well as its care by nursing and other health professionals. These changes include increased overdoses (primarily from synthetic opioids such as fentanyl) and emergency department visits. These trends varied considerably across U.S. jurisdictions, underscoring the importance of region-specific examinations for public health policy and intervention. Out of necessity, healthcare systems and nursing professionals adapted to the challenges of OUD care in the pandemic. These adaptations included increases in telehealth services, increases in take-home doses of methadone or buprenorphine/naloxone, and expansion of layperson training in the use of naloxone for overdose reversal. It is likely that some of these adaptations will result in long-term changes in standards of care practices for OUDs by nursing professionals., Competing Interests: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article., (Copyright © 2024 International Nurses Society on Addictions.)
- Published
- 2024
- Full Text
- View/download PDF
8. Contemporary management of advanced colorectal cancer: the Australian experience.
- Author
-
Brown KG, Ansari N, and Solomon MJ
- Subjects
- Humans, Australia epidemiology, Retrospective Studies, Neoplasm Recurrence, Local, Colorectal Neoplasms therapy, Colorectal Neoplasms surgery, Pelvic Exenteration
- Published
- 2024
- Full Text
- View/download PDF
9. Neuromodulation: What the neurointerventionalist needs to know.
- Author
-
Mensah-Brown KG, Naylor RM, Graepel S, and Brinjikji W
- Abstract
Neuromodulation is the alteration of neural activity in the central, peripheral, or autonomic nervous systems. Consequently, this term lends itself to a variety of organ systems including but not limited to the cardiac, nervous, and even gastrointestinal systems. In this review, we provide a primer on neuromodulation, examining the various technological systems employed and neurological disorders targeted with this technology. Ultimately, we undergo a historical analysis of the field's development, pivotal discoveries and inventions gearing this review to neuro-adjacent subspecialties with a specific focus on neurointerventionalists., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
- Published
- 2024
- Full Text
- View/download PDF
10. The importance of recognizing Buffer Zones to lands being developed, restored, or remediated: on planning for protection of ecological resources.
- Author
-
Burger J, Gochfeld M, Brown KG, Ng K, Cortes M, and Kosson D
- Subjects
- Conservation of Natural Resources, Ecosystem, Environmental Restoration and Remediation
- Abstract
Environmental management relies on many types of information before making decisions regarding remediation, restoration, or other land use decisions, including ecological data, such as risks to species, populations, communities, and ecosystems. The aim of this investigation was to describe the ecological information required within the context of making environmental decisions and providing visual communication tools for regulators, conservationists, and the public to understand the risk to ecological resources on- and off-site. It is suggested that ecological information used in environmental decisions is required to be transparent throughout the planning and execution of a project, which needs to include: 1) ecological information and evaluations within development areas or units (in this case, watersheds), and 2) resources in adjacent areas (Buffer Zones) that might be affected. The Melton Valley administrative watershed (Oak Ridge Reservation, TN) is used as a case study because this site still has active facility development and environmental remediation, and there are important ecological resources on and off-site. Data indicate that although there are important resources on Melton Valley administrative watershed, there are also significant resources in the Buffer Zone around the watershed. Compared to the Melton Valley administrative watershed, the Buffer Zone contains more Interior (and Buffer) Forest and greater value resources. The point is made that when remediation, restoration, or development occurs, it is equally important to consider resources that are adjacent to the site in a Buffer Zone, particularly when remediation and development might continue for many years or decades.
- Published
- 2024
- Full Text
- View/download PDF
11. The Impact of the First Wave of the COVID-19 Pandemic on University Staff Dietary Behaviours, Sleeping Patterns, and Well-Being: An International Comparison Study.
- Author
-
Rabiee Khan F, Abdelraheim Titi M, Frankowska N, Kowalczyk K, Alziedan R, Yin-Kei Lau C, Biernat K, and Brown KG
- Subjects
- Humans, Female, Adult, Male, Universities, Pandemics, Cross-Sectional Studies, Feeding Behavior, Communicable Disease Control, Diet, Vegetables, COVID-19 epidemiology
- Abstract
This study assessed the impact of the first wave of the COVID-19 pandemic on well-being by measuring the changes to food security, dietary behaviour, and sleeping patterns of university staff in England, Poland, Saudi Arabia, and China. Using a cross-sectional study design, participants in four universities in the respective countries were surveyed between June and July 2020. The mean age of the 902 participants was 42 years old and 67% were female. The findings indicate a reduction in emotionally driven food behaviour [t (901.00) = -20.87, p < 0.001], food acquisition location [t (901.00) = -51.55, p < 0.001], skipping meals [t (901.00) = -24, p < 0.001], and consumption of canned fruit and vegetables [t (901.00) = -10.18, p < 0.001]. However, home cooking [t (901.00) = 36.61, p < 0.001] and the food shopping experience [t (901.00) = 4.53, p < 0.001] markedly increased during lockdown. The participants had higher levels of well-being during the pandemic and experienced a significant increase in sleeping hours ( p < 0.001). Increased age and sleeping hours were positively associated with overall well-being. Conversely, emotionally driven food behaviour (i.e., buying and eating more food out of boredom/fear or anxiety) and skipping meals decreased the overall well-being. Lockdown had beneficial effects on dietary behaviours, sleeping patterns, and well-being, but there were variations between countries.
- Published
- 2023
- Full Text
- View/download PDF
12. Neurosurgical robots in China: State of the art and future prospect.
- Author
-
Zhou S, Gao Y, Li R, Wang H, Zhang M, Guo Y, Cui W, Brown KG, Han C, Shi L, Liu H, Zhang J, Li Y, and Meng F
- Abstract
Neurosurgical robots have developed for decades and can effectively assist surgeons to carry out a variety of surgical operations, such as biopsy, stereo-electroencephalography (SEEG), deep brain stimulation (DBS), and so forth. In recent years, neurosurgical robots in China have developed rapidly. This article will focus on several key skills in neurosurgical robots, such as medical imaging systems, automatic manipulator, lesion localization techniques, multimodal image fusion technology, registration method, and vascular imaging technology; introduce the clinical application of neurosurgical robots in China, and look forward to the potential improvement points in the future based on our experience and research in the field., Competing Interests: The authors declare no competing interests., (© 2023 The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
13. Electroencephalography as a tool to predict cerebral oxygen metabolism during deep-hypothermic circulatory arrest in neonates with critical congenital heart disease.
- Author
-
Laurent GH, Ko TS, Mensah-Brown KG, Mavroudis CD, Jacobwitz M, Ranieri N, Nicolson SC, Gaynor JW, Baker WB, Licht DJ, Massey SL, and Lynch JM
- Abstract
Objectives: Recent research suggests that increased cerebral oxygen use during surgical intervention for neonates with congenital heart disease may play a role in the development of postoperative white matter injury. The objective of this study is to determine whether increased cerebral electrical activity correlates with greater decrease of cerebral oxygen saturation during deep hypothermic circulatory arrest., Methods: Neonates with critical congenital heart disease requiring surgical intervention during the first week of life were studied. All subjects had continuous neuromonitoring with electroencephalography and an optical probe (to quantify cerebral oxygen saturation) during cardiac surgical repair that involved the use of cardiopulmonary bypass and deep hypothermic circulatory arrest. A simple linear regression was used to investigate the association between electroencephalography metrics before the deep hypothermic circulatory arrest period and the change in cerebral oxygen saturation during the deep hypothermic circulatory arrest period., Results: Sixteen neonates had both neuromonitoring modalities attached during surgical repair. Cerebral oxygen saturation data from 5 subjects were excluded due to poor data quality, yielding a total sample of 11 neonates. A simple linear regression model found that the presence of electroencephalography activity at the end of cooling is positively associated with the decrease in cerebral oxygen saturation that occurs during deep hypothermic circulatory arrest ( P < .05)., Conclusions: Electroencephalography characteristics within 5 minutes before the initiation of deep hypothermic circulatory arrest may be useful in predicting the decrease in cerebral oxygen saturation that occurs during deep hypothermic circulatory arrest. Electroencephalography may be an important tool for guiding cooling and the initiation of circulatory arrest to potentially decrease the prevalence of new white matter injury in neonates with critical congenital heart disease., (© 2023 The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
14. Comparing land cover and interior forests on contaminated land and the surrounding region: Oak Ridge Reservation as a case study.
- Author
-
Burger J, Gochfeld M, Giffen N, Brown KG, Cortes M, Ng K, and Kosson DS
- Subjects
- Databases, Factual, Ecosystem, Conservation of Natural Resources methods, Forests
- Abstract
Pressure from expanding populations has resulted in a need for protection, reclamation, and restoration of damaged land to productive, beneficial health uses. The objective of this investigation was to 1) compare land cover on the Department of Energy (DOE) Oak Ridge Reservation (ORR) with the surrounding region, 2) select an indicator to evaluate ORR's protection of ecological resources, and 3) develop and implement a method to compare the amount of the indicator on ORR with the regions using National Land Cover Database (NLCD). Data demonstrated that ORR has a higher % of forests (deciduous, coniferous, mixed) than the 10 km and 30 km areas surrounding ORR, suggesting that obligations are being met to protect the ecology and environment. The findings also indicate that the interior forest at ORR is fragmented more than is the interior forest in the 30 km buffer zone, suggesting a need for DOE and managers of other lands to take into consideration the importance of intact interior forest when developing land or planning roads. The study describes the basis for specific ecological parameters such as interior forest that are important to consider when planning and executing remediation, restoration, and other management actions.
- Published
- 2023
- Full Text
- View/download PDF
15. Evaluating the impact of drying on leaching from a solidified/stabilized waste using a monolithic diffusion model.
- Author
-
Chen Z, Zhang P, Brown KG, van der Sloot HA, Meeussen JCL, Garrabrants AC, Delapp RC, Um W, and Kosson DS
- Abstract
The release rates of constituents of potential concern from solidified/stabilized cementitious waste forms are potentially impacted by drying, which, however, is not well understood. This study aimed to identify the impacts of drying on subsequent leaching from Cast Stone as an example of a solidified cementitious waste form. The release fluxes of constituents from monoliths after aging under 100, 68, 40, and 15 % relative humidity for 16, 32, and 48 weeks, respectively, were derived from mass transfer tank leaching tests following EPA Method 1315. A monolithic diffusion model was calibrated based on the leaching test results to simulate the leaching of major and redox-sensitive constituents from monoliths after drying. The reduction in physical retention of constituents (tortuosity-factor) in the unsaturated zone was identified as the primary impact from drying on subsequent leaching. Fluxes of both major (i.e., OH
- , Na, K, Ca, Si, and Al) and redox-sensitive constituents (i.e., Tc, Cr, Fe, and S) from monoliths during leaching were well described by the model. The drying-induced reduction of tortuosity-factor and concomitant changes in porewater pH and redox conditions can significantly change the subsequent release fluxes of pH- and redox- sensitive constituents., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)- Published
- 2023
- Full Text
- View/download PDF
16. Impact of oxidation and carbonation on the release rates of iodine, selenium, technetium, and nitrogen from a cementitious waste form.
- Author
-
Chen Z, Zhang P, Brown KG, van der Sloot HA, Meeussen JCL, Garrabrants AC, Wang X, Delapp RC, and Kosson DS
- Abstract
Evaluation of the long-term retention mechanisms and potential release rates for the primary constituents of potential concern (COPCs) (i.e., Tc, I, Se, and nitrate) is necessary to determine if Cast Stone, a radioactive waste form, can meet performance objectives under near-surface disposal scenarios. Herein, a mineral and parameter set accounting for the solubility of I and Se in Cast Stone was developed based on pH-dependent and monolithic diffusion leaching test results, to extend a geochemical speciation model previously developed. The impact of oxidation and carbonation as environmental aging processes on the retention properties of Cast Stone for primary COPCs was systematically estimated. Physically, the effective diffusion coefficients of 4 COPCs in Cast Stone were increased after carbonation and/or oxidation, reflecting an increase in permeability to diffusion. Chemically, i) pH & pe conditions in the original Cast Stone were favorable for the stabilization of Tc, but not for I, Se, and N; ii) oxidation (with/without carbonation) of Cast Stone changed the pe & pH conditions to be detrimental for Tc stabilization; and iii) carbonation (with/without oxidation) of Cast Stone modified the pH & pe conditions to be beneficial for the stabilization of I (in system with Ag added) and Se., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
17. Assessment of Transarterial Chemoembolization Using Super-resolution Ultrasound Imaging and a Rat Model of Hepatocellular Carcinoma.
- Author
-
Brown KG, Li J, Margolis R, Trinh B, Eisenbrey JR, and Hoyt K
- Subjects
- Animals, Rats, Contrast Media chemistry, Ultrasonography methods, Treatment Outcome, Carcinoma, Hepatocellular diagnostic imaging, Carcinoma, Hepatocellular therapy, Carcinoma, Hepatocellular pathology, Liver Neoplasms diagnostic imaging, Liver Neoplasms therapy, Liver Neoplasms pathology, Chemoembolization, Therapeutic methods
- Abstract
Objective: Hepatocellular carcinoma (HCC) is a highly prevalent form of liver cancer diagnosed annually in 600,000 people worldwide. A common treatment is transarterial chemoembolization (TACE), which interrupts the blood supply of oxygen and nutrients to the tumor mass. The need for repeat TACE treatments may be assessed in the weeks after therapy with contrast-enhanced ultrasound (CEUS) imaging. Although the spatial resolution of traditional CEUS has been restricted by the diffraction limit of ultrasound (US), this physical barrier has been overcome by a recent innovation known as super-resolution US (SRUS) imaging. In short, SRUS enhances the visible details of smaller microvascular structures on the 10 to 100 µm scale, which unlocks a host of new clinical opportunities for US., Methods: In this study, a rat model of orthotopic HCC is introduced and TACE treatment response (to a doxorubicin-lipiodol emulsion) is assessed using longitudinal SRUS and magnetic resonance imaging (MRI) performed at 0, 7 and 14 d. Animals were euthanized at 14 d for histological analysis of excised tumor tissue and determination of TACE response, that is, control, partial response or complete response. CEUS imaging was performed using a pre-clinical US system (Vevo 3100, FUJIFILM VisualSonics Inc.) equipped with an MX201 linear array transducer. After administration of a microbubble contrast agent (Definity, Lantheus Medical Imaging), a series of CEUS images were collected at each tissue cross-section as the transducer was mechanically stepped at 100 μm increments. SRUS images were formed at each spatial position, and a microvascular density metric was calculated. Microscale computed tomography (microCT, OI/CT, MILabs) was used to confirm TACE procedure success, and tumor size was monitored using a small animal MRI system (BioSpec 3T, Bruker Corp.)., Results: Although there were no differences at baseline (p > 0.15), both microvascular density levels and tumor size measures from the complete responder cases at 14 d were considerably lower and smaller, respectively, than those in the partial responder or control group animals. Histological analysis revealed tumor-to-necrosis levels of 8.4%, 51.1% and 100%, for the control, partial responder and complete responder groups, respectively (p < 0.005)., Conclusion: SRUS imaging is a promising modality for assessing early changes in microvascular networks in response to tissue perfusion-altering interventions such as TACE treatment of HCC., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2023 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
18. Application and uncertainty of a geochemical speciation model for predicting oxyanion leaching from coal fly ash under different controlling mechanisms.
- Author
-
Wang X, van der Sloot HA, Brown KG, Garrabrants AC, Chen Z, Hensel B, and Kosson DS
- Abstract
Three primary mechanisms (adsorption to iron oxides or analogous surfaces, co-precipitation with Ca, and substitution in ettringite) controlling oxyanion retention in coal fly ashes (CFAs) were identified by differentiating the leaching behavior of As, B, Cr, Mo, Se, and V from 30 CFAs. Fidelity evaluation of geochemical speciation modeling focused on six reference CFAs representing a range of CFA compositions, whereby different leaching-controlling mechanisms of oxyanions were systematically considered. For three reference CFAs with low Ca and S content, calibration of adsorption reactions for the diffuse double-layer model for hydrous ferric oxides improved the simultaneous prediction of oxyanion leaching, which reduced uncertainties in Se and V predictions caused by nonideal adsorption surfaces and competitive adsorption effects. For two reference CFAs with intermediate Ca content, the solubility constants for Ca-arsenates from literature and postulated phases of B, Cr, Se, and V were used to describe co-precipitation of oxyanions with Ca-bearing minerals under alkaline conditions. For the reference CFA with high Ca and S content, an ettringite solid solution was used to capture the simultaneous retention of all oxyanions at pH> 9.5. Overall, the simultaneous leaching predictions of oxyanions from a wide range of CFAs were improved by calibration of adsorption reactions and controlling solid phases., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
19. Has the United States Reached a Plateau in Overdoses Caused by Synthetic Opioids After the Onset of the COVID-19 Pandemic? Examination of Centers for Disease Control and Prevention Data to November 2021.
- Author
-
Brown KG, Chen CY, Dong D, Lake KJ, and Butelman ER
- Abstract
Background: Overdoses caused by synthetic mu-opioid receptor (MOR) agonists such as fentanyl are causing increasing mortality in the United States. The COVID-19 pandemic continues to have complex effects on public health, including opioid use disorders (OUD). It is unclear whether recent increases in mortality caused by synthetic opioids have reached a plateau (i.e., a stable period), after the onset of the COVID-19 pandemic., Method: This study examined provisional overdose mortality data from the Centers for Disease Control and Prevention, for synthetic opioids excluding methadone (code T40.4; monthly data available from 39 States, plus New York City and Washington DC), for June 2019-November 2021. Data were first examined as crude mortality rates. The presence of a maximum plateau was analyzed for the last 4 months of available data. For authorities in which a plateau in mortality was detected, sigmoidal Boltzmann equations were used to model parameters of this phenomenon (e.g., level of the plateau)., Results: At the end of the study period, all but one authority (New Hampshire) reported increases in mortality rates for synthetic opioids, compared to the baseline month of June 2019 (range: 111-745% of baseline). A plateau was observed over the last 4 months of the study period (Aug 2021-Nov 2021) in 29 of the authorities. Ten other authorities had not reached a stable plateau at the end of the study period. For the authorities where a plateau was detected, a sigmoidal Boltzmann model revealed a fitted maximum of 262% rise in mortality over the study period, from the baseline month. The midpoint in the rise in mortality was fitted in September 2020. After separation of data into census regions, the highest plateau was observed in the West region, followed by South, Midwest, and Northeast (fitted plateau values were 409, 262, 204, and 149% of baseline, respectively)., Discussion: There were increases in overdose mortality due to synthetic opioids across most states, ranging considerably in magnitude. A plateau in overdose mortality was detected at the end of the study period in most of these authorities. The reasons for these plateaus should be explored, in order to develop optimized public health interventions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Brown, Chen, Dong, Lake and Butelman.)
- Published
- 2022
- Full Text
- View/download PDF
20. Impact of carbonation on leaching of constituents from a cementitious waste form for treatment of low activity waste at the DOE Hanford site.
- Author
-
Zhang P, Chen Z, Brown KG, Garrabrants AC, Delapp R, Meeussen JCL, van der Sloot HA, and Kosson DS
- Subjects
- Carbon Dioxide chemistry, Nitrogen, Solubility, Carbonates chemistry, Chromium
- Abstract
Carbonation can be a major aging process during disposal of alkaline cementitious waste forms and can impact constituent leaching by changes in material alkalinity, pore structure, and controlling mineral phases. The effect of carbonation on the leaching of major and trace constituents from Cast Stone, a cementitious waste form developed to treat high salt content low activity waste, was studied through a combination of leaching experiments and reactive transport simulations. Diffusive transport of constituents in the waste form was evaluated using reactive transport modeling of diffusion-controlled leaching test results and a geochemical speciation model derived from pH-dependent leaching. Comparisons between Cast Stone materials aged under nitrogen, air, and 2% carbon dioxide in nitrogen showed that carbonation impacts solubility, physical retention and observed diffusivity of major and trace constituents. Carbonation under 2% CO
2 decreased the diffusion-controlled leaching of chromium by two orders of magnitude. Modeling results suggest that carbonation may also decrease solubility of technetium while changes to microstructure by carbonation increases effective diffusivity of constituents in Cast Stone., (Copyright © 2022 Elsevier Ltd. All rights reserved.)- Published
- 2022
- Full Text
- View/download PDF
21. Effects of circulatory arrest and cardiopulmonary bypass on cerebral autoregulation in neonatal swine.
- Author
-
Padawer-Curry JA, Volk LE, Mavroudis CD, Ko TS, Morano VC, Busch DR, Rosenthal TM, Melchior RW, Shade BC, Schiavo KL, Boorady TW, Schmidt AL, Andersen KN, Breimann JS, Jahnavi J, Mensah-Brown KG, Yodh AG, Mascio CE, Kilbaugh TJ, Licht DJ, White BR, and Baker WB
- Subjects
- Animals, Animals, Newborn, Cerebrovascular Circulation, Homeostasis, Swine, Cardiopulmonary Bypass adverse effects, Hypothermia, Induced
- Abstract
Background: Cerebral autoregulation mechanisms help maintain adequate cerebral blood flow (CBF) despite changes in cerebral perfusion pressure. Impairment of cerebral autoregulation, during and after cardiopulmonary bypass (CPB), may increase risk of neurologic injury in neonates undergoing surgery. In this study, alterations of cerebral autoregulation were assessed in a neonatal swine model probing four perfusion strategies., Methods: Neonatal swine (n = 25) were randomized to continuous deep hypothermic cardiopulmonary bypass (DH-CPB, n = 7), deep hypothermic circulatory arrest (DHCA, n = 7), selective cerebral perfusion (SCP, n = 7) at deep hypothermia, or normothermic cardiopulmonary bypass (control, n = 4). The correlation coefficient (LDx) between laser Doppler measurements of CBF and mean arterial blood pressure was computed at initiation and conclusion of CPB. Alterations in cerebral autoregulation were assessed by the change between initial and final LDx measurements., Results: Cerebral autoregulation became more impaired (LDx increased) in piglets that underwent DH-CPB (initial LDx: median 0.15, IQR [0.03, 0.26]; final: 0.45, [0.27, 0.74]; p = 0.02). LDx was not altered in those undergoing DHCA (p > 0.99) or SCP (p = 0.13). These differences were not explained by other risk factors., Conclusions: In a validated swine model of cardiac surgery, DH-CPB had a significant effect on cerebral autoregulation, whereas DHCA and SCP did not., Impact: Approximately half of the patients who survive neonatal heart surgery with cardiopulmonary bypass (CPB) experience neurodevelopmental delays. This preclinical investigation takes steps to elucidate and isolate potential perioperative risk factors of neurologic injury, such as impairment of cerebral autoregulation, associated with cardiac surgical procedures involving CPB. We demonstrate a method to characterize cerebral autoregulation during CPB pump flow changes in a neonatal swine model of cardiac surgery. Cerebral autoregulation was not altered in piglets that underwent deep hypothermic circulatory arrest (DHCA) or selective cerebral perfusion (SCP), but it was altered in piglets that underwent deep hypothermic CBP., (© 2021. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
22. The influence of redox conditions on aqueous-solid partitioning of arsenic and selenium in a closed coal ash impoundment.
- Author
-
Wang X, Garrabrants AC, Chen Z, van der Sloot HA, Brown KG, Qiu Q, Delapp RC, Hensel B, and Kosson DS
- Subjects
- Coal analysis, Coal Ash, Ferric Compounds, Oxidation-Reduction, Arsenic, Selenium
- Abstract
A closed coal ash impoundment case study characterized the effects of field redox conditions on arsenic and selenium partitioning through monitoring of porewater and subsurface gas in conjunction with geochemical speciation modeling. When disposed coal ash materials and porewater were recovered for testing, oxidation led to lower arsenic and higher selenium concentrations in leaching test extracts compared to porewater measurements. Multiple lines of evidence suggest multiple mechanisms of arsenic retention are plausible and the concurrent presence of several redox processes and conditions (e.g., methanogenesis, sulfate reduction, and Fe(III)-reduction) controlled by spatial gradients and dis-equilibrium. Geochemical speciation modeling indicated that, under reducing field conditions, selenium was immobilized through the formation of insoluble precipitates Se(0) or FeSe while arsenic partitioning was affected by a progression of reactions including changes in arsenic speciation, reduction in adsorption due to dissolution and recrystallization of hydrous ferric oxides, and precipitation of arsenic sulfide minerals., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
23. Magnetic Resonance-Guided Focused Ultrasound Thalamotomy for Essential Tremor Under General Anesthesia: Technical Note.
- Author
-
Mensah-Brown KG, Yang AI, Hitti FL, Henry L, Heman-Ackah SM, Chaibainou H, and Baltuch GH
- Subjects
- Anesthesia, General, Humans, Magnetic Resonance Imaging methods, Magnetic Resonance Spectroscopy, Male, Thalamus diagnostic imaging, Thalamus surgery, Essential Tremor diagnostic imaging, Essential Tremor surgery
- Abstract
Background: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is an incisionless therapy for the treatment of medication-resistant essential tremor. Although its safety and efficacy has been demonstrated, MRgFUS is typically performed with the patient awake, with intraprocedural neurological assessments to guide lesioning., Objective: To report the first case of MRgFUS thalamotomy under general anesthesia in a patient whose medical comorbidities prohibit him from being in a supine position without a secured airway., Methods: The dentatorubrothalamic tract was directly targeted. Two sonications reaching lesional temperatures (≥54°C) were delivered without any complications., Results: Lesioning was confirmed on intraoperative magnetic resonance imaging, and the patient experienced 89% improvement in his tremor postoperatively., Conclusion: This demonstrates the safety and feasibility of MRgFUS thalamotomy under general anesthesia without the benefit of intraprocedural neurological assessments., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
24. Combining ecological, eco-cultural, and environmental justice parameters to create Eco-EJ indicators to monitor cultural and environmental justices for diverse communities around contaminated sites.
- Author
-
Burger J, Gochfeld M, Kosson DS, Brown KG, Salisbury J, Greenberg M, and Jeitner C
- Subjects
- Environment, Environmental Monitoring, Humans, Risk Assessment, Ecosystem, Environmental Justice
- Abstract
Assessing environmental quality often requires selection of indicators that can be employed over large spatial scales and over long-time periods to assess the health and well-being of species, natural communities, and ecosystems, and to detect changes warranting intervention. Typically, the ecologic environment and the human environment are evaluated separately and selection of indicators and monitoring approaches are not integrated even though ecological indicators may also provide information on risk to human consumers from contaminants (e.g., eco-cultural indicators) or because of disease levels. This paper is a call for ecologists and managers to consider diverse cultural and environmental injustice disparities and health issues when selecting indicators for environmental assessment and monitoring. There is an opportunity for managers and community members to work together to preserve ecological and cultural resources and heritages. We propose a paradigm that selects indicators and monitoring approaches that lend themselves to the integration of human-diversity and uniqueness in the same manner that the selection of ecological indicators and monitoring approaches consider biological species diversity and uniqueness. The proposed paradigm builds on ecological risk assessment techniques, developing analogous endpoints for neighboring communities. For example, identification and protection of human communities, particularly culturally diverse and environmental justice communities, identification of contaminant corridors (e.g., through water or green corridors) into communities, and eco-monitoring of vulnerable communities are not routine at contaminated sites. Green corridors refers to a width of wild habitat (forest, grasslands) that connects other similar habitat paths (usually a corridor runs through an urban or suburban habitat). We coin the term Eco-EJ indicators for these endpoints, including examination of (1) unique cultural relationships to resources; (2) connectedness of on-site and off-site resources and habitats; (3) health of threatened, rare, and unique cultures and communities; and (4) linkages between ecological, eco-cultural, and public health for monitoring and assessment. We also propose that assessment and monitoring include these Eco-EJ indicators, especially for communities near facilities that have extensive chemical or radiological contamination.Developing these indicators to assess risk to culturally diverse and environmental justice communities would be an equivalent goal to reducing risk for significant ecological resources (e.g., endangered species, species of special concern). These Eco-EJ indicators are complementary to the usual human health-risk assessments, would include surveys of neighboring vulnerable communities, and require time and re-organization of current data and additional data collection at site boundaries and in adjacent communities, as well as rethinking the human component of indicators. This approach lends itself to addressing some diverse cultural and environmental justice issues with current indicator selection and biomonitoring, and helps identify specific hotspots of unique ecosystem risk and environmental justice community risk. We briefly discuss ecological and eco-cultural monitoring already on-going at three Department of Energy sites to illustrate how the addition of these indicators might work and add value to environmental management and to their relationships with surrounding communities. We recommend that managers of contaminated sites convene people from culturally diverse communities, environmental justice communities, local and federal government, Tribes, resource trustees, managers, and other stakeholders to develop appropriate site-specific indicators to address environmental inequities around contaminated facilities., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)
- Published
- 2022
- Full Text
- View/download PDF
25. Bidirectional influence of heroin and cocaine escalation in persons with dual opioid and cocaine dependence diagnoses.
- Author
-
Butelman ER, Chen CY, Lake KJ, Brown KG, and Kreek MJ
- Subjects
- Adolescent, Analgesics, Opioid, Female, Heroin, Humans, Infant, Male, Cocaine, Cocaine-Related Disorders diagnosis, Cocaine-Related Disorders epidemiology, Heroin Dependence diagnosis, Opioid-Related Disorders diagnosis, Opioid-Related Disorders epidemiology
- Abstract
Persons with dual severe opioid and cocaine use disorders are at risk of considerable morbidity, and the bidirectional relationship of escalation of mu-opioid agonists and cocaine use is not well understood. The aim of this study was to examine the bidirectional relationship between escalation of heroin and cocaine use in volunteers dually diagnosed with opioid and cocaine dependence (OD + CD). Volunteers from New York with OD + CD (total n = 295; male = 182, female = 113; age ≥ 18 years) were interviewed with the Structured Clinical Interview for the DSM-IV Axis I Disorders and Kreek-McHugh-Schluger-Kellogg scales for dimensional measures of drug exposure, which also collect ages of 1st use and onset of heaviest use. Time of escalation was defined as age of onset of heaviest use minus age of 1st use in whole years. Times of escalation of heroin and cocaine were positively correlated in both men (Spearman r = .34, 95% confidence interval [CI: .17, .48], p < .0001) and women (Spearman r = .51, [.27, .50], p < .0001) volunteers. After we adjusted for demographic variables, a Cox regression showed that time of cocaine escalation was a predictor of time of heroin escalation (hazard ratio [HR] = 0.97, 95% CI [0.95, 0.99], p = .003). Another Cox regression showed that this relationship is bidirectional, because time of heroin escalation was also a predictor of time of cocaine escalation (HR = 0.98, [0.96-0.99], p = .016). In these adjusted models, gender was not a significant predictor of time of escalation of either heroin or cocaine. Therefore, escalation did not differ robustly by gender when adjusting for demographics and other major variables. Overall, rapid escalation of cocaine use was a predictor of rapid escalation of heroin use, and vice versa, in persons with dual severe opioid and cocaine use disorders. These findings suggest a shared vulnerability to rapid escalation of these 2 drugs in persons with dual severe opioid and cocaine use disorders. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
- Published
- 2022
- Full Text
- View/download PDF
26. Use of Second Window ICG in spinal cord biopsy of a mildly contrast-enhancing lesion: Technical note and review of the literature.
- Author
-
Mensah-Brown KG, Germi JW, Quattrone F, Maloney-Wilensky E, Lee JYK, Chen HI, and Schuster JM
- Subjects
- Adult, Biopsy, Female, Humans, Indocyanine Green, Young Adult, Brain Neoplasms diagnostic imaging, Brain Neoplasms surgery, Spinal Cord Neoplasms diagnostic imaging, Spinal Cord Neoplasms surgery
- Abstract
Introduction: Indocyanine green (ICG) is commonly used to visualize cerebral vasculature, particularly in the management of cerebral aneurysms. There have also been attempts to use ICG for visualization of tumors. Injection of ICG followed by immediate fluorescence microscopy is limited by the short time window for imaging and administration and restricted depth of imaging. Second Window Indocyanine Green (SWIG) addresses these issues by allowing for longer contrast times and the imaging of deeper regions of brain tissue. Biopsy of spinal cord lesions is often difficult for a variety of reasons, including the delicate nature of the tissue and differentiating normal from lesional tissue visually, especially in lesions with heterogeneous enhancement., Methods: In this case report, we describe the use of second window ICG to facilitate the visualization of a spinal cord lesion and subsequent biopsy of the lesion., Results: This patient is a 24-year-old female who had recurrence of a suprasellar germinoma. An MRI of the rest of the neuraxis was performed to assess for the presence of drop metastases. The spinal cord from C2-5 was expanded with areas of patchy enhancement; however, this lesion was asymptomatic. The patient's oncologist requested a biopsy of this lesion to help direct subsequent care of her recurrent germinoma. The day before surgery, the patient had an intravenous injection of ICG dye. She then underwent a C3-5 laminectomy for biopsy of her cervical intramedullary lesion. After opening of the dura, no visible abnormality of the spinal cord could be identified. A Stryker endoscope showed an area of ICG uptake in the cord at approximately the C3-4 level. A midline myelotomy was centered over the ICG demarcated area and several samples were taken for pathology. Final biopsy results determined the lesion to be spinal cord parenchyma with perivascular and intraparenchymal lymphocytes - not consistent with spinal cord tumor or germinoma., Conclusion: Second Window ICG is effective in visualizing otherwise visually unremarkable spinal cord lesions. This technology can facilitate biopsy of these lesions and possibly their surgical resection., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
27. Gamma Knife radiosurgery for trigeminal neuralgia provides greater pain relief at higher dose rates.
- Author
-
Yang AI, Mensah-Brown KG, Shekhtman EF, Kvint S, Wathen CA, Hitti FL, Alonso-Basanta M, Avery SM, Dorsey JF, and Y K Lee J
- Abstract
In Gamma Knife (GK) radiosurgery, dose rate decreases during the life cycle of its radiation source, extending treatment times. Prolonged treatments influence the amount of sublethal radiation injury that is repaired during exposure, and is associated with decreased biologically-equivalent dose (BED). We assessed the impact of treatment times on clinical outcomes following GK of the trigeminal nerve - a rare clinical model to isolate the effects of treatment times. This is a retrospective analysis of 192 patients with facial pain treated across three source exchanges. All patients were treated to 80 Gy with a single isocenter. Treatment time was analyzed in terms of patient anatomy-specific dose rate, as well as BED calculated from individual patient beam-on times. An outcome tool measuring pain in three distinct domains (pain intensity, interference with general and oro-facial activities of daily living), was administered before and after intervention. Multivariate linear regression was performed with dose rate/BED, brainstem dose, sex, age, diagnosis, and prior intervention as predictors. BED was an independent predictor of the degree of improvement in all three dimensions of pain severity. A decrease in dose rate by 1.5 Gy/min corresponded to 31.8% less improvement in the overall severity of pain. Post-radiosurgery incidence of facial numbness was increased for BEDs in the highest quartile. Treatment time is an independent predictor of pain outcomes, suggesting that prescription dose should be customized to ensure iso-effective treatments, while accounting for the possible increase in adverse effects at the highest BEDs., Competing Interests: Authors’ disclosure of potential conflicts of interest The authors have nothing to disclose., (© 2022 Old City Publishing, Inc.)
- Published
- 2022
28. Evaluation of Nonlinear Contrast Pulse Sequencing for Use in Super-Resolution Ultrasound Imaging.
- Author
-
Brown KG and Hoyt K
- Subjects
- Animals, Phantoms, Imaging, Rats, Ultrasonics, Ultrasonography, Contrast Media, Microbubbles
- Abstract
The use of super-resolution ultrasound (SR-US) imaging greatly improves visualization of microvascular structures, but clinical adoption is limited by long imaging times. This method depends on detecting and localizing isolated microbubbles (MBs), forcing the use of a dilute contrast agent concentration. Contrast-enhanced ultrasound (CEUS) image acquisition times as long as minutes arise as the localization of thousands of MBs are acquired to form a complete SR-US image. In this article, we explore the use of nonlinear CEUS strategies using nonlinear fundamental contrast pulse sequencing (CPS) to increase the contrast-to-tissue ratio (CTR) and compare MB detection effectiveness to linear B-mode CEUS imaging. The CPS compositions of amplitude modulation (AM), pulse inversion (PI), and a combination of the two (AMPI) were studied. A simulation study combined the Rayleigh-Plesset-Marmottant (RPM) model of MB characteristics and a nonlinear tissue model using the k-Wave toolbox for MATLAB (MathWorks Inc., Natick, MA, USA). Validation was conducted using an in vitro flow phantom and in vivo in the rat hind-limb. Imaging was performed with a programmable US scanner (Vantage 256, Verasonics Inc., Kirkland, WA, USA) and customized to transmit a set of basis US pulses from which both B-mode US (frame rate (FR) of 800 Hz) and multiple nonlinear CPS compositions (FR of 200 Hz) could be assessed from identical in vitro and in vivo datasets using a near simultaneous method. The simulations suggest that MB characteristics, such as diameter and motion, help to predict which US imaging strategy will enhance MB detection. The in vitro and in vivo US imaging studies revealed that different subpopulations of polydisperse MB contrast agents were detected by linear imaging and by each different nonlinear CPS composition. The most effective single imaging strategy at a 200-Hz FR was found to be B-mode US imaging. However, a combination of B-mode US imaging with a nonlinear CPS imaging strategy was more effective in detecting MBs in vivo at all depths and was shown to shorten image acquisition time by an average of 33.3%-76.7% when combining one or more CPS sequences.
- Published
- 2021
- Full Text
- View/download PDF
29. Faster super-resolution ultrasound imaging with a deep learning model for tissue decluttering and contrast agent localization.
- Author
-
Brown KG, Waggener SC, Redfern AD, and Hoyt K
- Subjects
- Animals, Contrast Media, Microbubbles, Phantoms, Imaging, Rats, Ultrasonography, Deep Learning
- Abstract
Super-resolution ultrasound (SR-US) imaging allows visualization of microvascular structures as small as tens of micrometers in diameter. However, use in the clinical setting has been impeded in part by ultrasound (US) acquisition times exceeding a breath-hold and by the need for extensive offline computation. Deep learning techniques have been shown to be effective in modeling the two more computationally intensive steps of microbubble (MB) contrast agent detection and localization. Performance gains by deep networks over conventional methods are more than two orders of magnitude and in addition the networks can localize overlapping MBs. The ability to separate overlapping MBs allows use of higher contrast agent concentrations and reduces US image acquisition time. Herein we propose a fully convolutional neural network (CNN) architecture to perform the operations of MB detection as well as localization in a single model. Termed SRUSnet, the network is based on the MobileNetV3 architecture modified for 3-D input data, minimal convergence time, and high-resolution data output using a flexible regression head. Also, we propose to combine linear B-mode US imaging and nonlinear contrast pulse sequencing (CPS) which has been shown to increase MB detection and further reduce the US image acquisition time. The network was trained with in silico data and tested on in vitro data from a tissue-mimicking flow phantom, and on in vivo data from the rat hind limb ( N = 3). Images were collected with a programmable US system (Vantage 256, Verasonics Inc., Kirkland, WA) using an L11-4v linear array transducer. The network exceeded 99.9% detection accuracy on in silico data. The average localization accuracy was smaller than the resolution of a pixel (i.e.λ/8). The average processing time on a Nvidia GeForce 2080Ti GPU was 64.5 ms for a 128 × 128-pixel image., (© 2021 IOP Publishing Ltd.)
- Published
- 2021
- Full Text
- View/download PDF
30. Age of onset of heaviest use of cannabis or alcohol in persons with severe opioid or cocaine use disorders.
- Author
-
Butelman ER, Chen CY, Brown KG, Lake KJ, and Kreek MJ
- Subjects
- Adolescent, Adult, Age of Onset, Analgesics, Opioid, Humans, Young Adult, Alcoholism epidemiology, Cannabis adverse effects, Cocaine, Marijuana Abuse epidemiology, Opioid-Related Disorders epidemiology, Substance-Related Disorders
- Abstract
Background: Persons with severe opioid or cocaine use disorders are particularly vulnerable to morbidity and mortality. Heaviest use of mu-opioid receptor agonists and cocaine typically commences in early adulthood and is preceded by substantial adolescent exposure to cannabis and/or alcohol. Little information exists on the age trajectories of exposure to cannabis or alcohol in persons diagnosed with severe opioid or cocaine use disorders, compared to persons diagnosed with other substance use disorders (unrelated to opioids or cocaine)., Method: This observational study had n = 854 volunteers (male = 581, female = 273; ≥18 years of age at the time of interview) and examined the ages of onset of heaviest use of cannabis and alcohol in persons diagnosed by DSM-IV criteria with opioid dependence (OD), both opioid and cocaine dependence (OD + CD) and cocaine dependence (CD). These age trajectory measures were compared to persons with other substance use disorders (primarily cannabis and alcohol use disorders, termed "Any Other Diagnoses")., Results: Unadjusted survival analyses showed persons diagnosed with either OD + CD or CD had earlier onset of heaviest use of cannabis (mean ages of 16.2 and 17.8, respectively) compared to the "Any Other Diagnoses" reference group (mean age = 19.5). A multivariate logistic regression showed that later onset of heaviest use of cannabis was associated with lower odds of being in the OD + CD or CD groups, when compared to the reference group., Conclusions: Persons diagnosed with severe cocaine use disorders or dual opioid and cocaine use disorders exhibit a pattern of heavy and especially early adolescent exposure to cannabis, compared to persons with other substance use disorders., (Copyright © 2021. Published by Elsevier B.V.)
- Published
- 2021
- Full Text
- View/download PDF
31. Development of an Intraoperative Pipeline for Holographic Mixed Reality Visualization During Spinal Fusion Surgery.
- Author
-
Buch VP, Mensah-Brown KG, Germi JW, Park BJ, Madsen PJ, Borja AJ, Haldar D, Basenfelder P, Yoon JW, Schuster JM, and Chen HI
- Subjects
- Humans, Imaging, Three-Dimensional, Neurosurgical Procedures, Augmented Reality, Spinal Fusion, Surgery, Computer-Assisted
- Abstract
Objective . Holographic mixed reality (HMR) allows for the superimposition of computer-generated virtual objects onto the operator's view of the world. Innovative solutions can be developed to enable the use of this technology during surgery. The authors developed and iteratively optimized a pipeline to construct, visualize, and register intraoperative holographic models of patient landmarks during spinal fusion surgery. Methods. The study was carried out in two phases. In phase 1, the custom intraoperative pipeline to generate patient-specific holographic models was developed over 7 patients. In phase 2, registration accuracy was optimized iteratively for 6 patients in a real-time operative setting. Results. In phase 1, an intraoperative pipeline was successfully employed to generate and deploy patient-specific holographic models. In phase 2, the registration error with the native hand-gesture registration was 20.2 ± 10.8 mm (n = 7 test points). Custom controller-based registration significantly reduced the mean registration error to 4.18 ± 2.83 mm (n = 24 test points, P < .01). Accuracy improved over time (B = -.69, P < .0001) with the final patient achieving a registration error of 2.30 ± .58 mm. Across both phases, the average model generation time was 18.0 ± 6.1 minutes (n = 6) for isolated spinal hardware and 33.8 ± 8.6 minutes (n = 6) for spinal anatomy. Conclusions. A custom pipeline is described for the generation of intraoperative 3D holographic models during spine surgery. Registration accuracy dramatically improved with iterative optimization of the pipeline and technique. While significant improvements and advancements need to be made to enable clinical utility, HMR demonstrates significant potential as the next frontier of intraoperative visualization.
- Published
- 2021
- Full Text
- View/download PDF
32. Development of a Geochemical Speciation Model for Use in Evaluating Leaching from a Cementitious Radioactive Waste Form.
- Author
-
Chen Z, Zhang P, Brown KG, Branch JL, van der Sloot HA, Meeussen JCL, Delapp RC, Um W, and Kosson DS
- Subjects
- Chromium analysis, Oxidation-Reduction, Water, Radioactive Waste analysis
- Abstract
Cast Stone has been developed to immobilize a fraction of radioactive waste at the Hanford Site; however, constituents of potential concern (COPCs) can be released when in contact with water during disposal. Herein, a representative mineral and parameter set for geochemical speciation modeling was developed for Cast Stone aged in inert and oxic environments, to simulate leaching concentrations of major and trace constituents. The geochemical speciation model was verified using a monolithic diffusion model in conjunction with independent monolithic diffusion test results. Eskolaite (Cr
2 O3 ) was confirmed as the dominant mineral retaining Cr in Cast Stone doped with 0.1 or 0.2 wt % Cr. The immobilization of Tc as a primary COPC in Cast Stone was evaluated, and the redox states of porewater within monolithic Cast Stone indicated by Cr are insufficient for the reduction of Tc. However, redox states provided by blast furnace slag (BFS) within the interior of Cast Stone are capable of reducing Tc for immobilization, with the immobilization reaction rate postulated to be controlled by the diffusive migration of soluble Tc in porewater to the surface of reducing BFS particles. Aging in oxic conditions increased the flux of Cr and Tc from monolithic Cast Stone.- Published
- 2021
- Full Text
- View/download PDF
33. Methodology for scenario-based assessments and demonstration of treatment effectiveness using the Leaching Environmental Assessment Framework (LEAF).
- Author
-
Garrabrants AC, Kosson DS, Brown KG, Fagnant DP Jr, Helms G, and Thorneloe SA
- Abstract
A methodology for developing scenario-based leaching assessments as part of the Leaching Environmental Assessment Framework (LEAF) is illustrated using a hypothetical management/treatment scenario of contaminated soil from a copper and lead smelter. Scenario assessments refine the process beyond screening-level assessments by considering site- and scenario-specific information about the disposal or utilization environment. LEAF assessments assume (i) granular materials leach at local equilibrium with percolating water, while (ii) monolithic materials (e.g., low permeability solidified/stabilized soils) leach by diffusion-based mass transport toward surrounding contact water. Leaching concentrations, estimated using LEAF leaching test data and estimated or measured scenario information, are compared to threshold values. Demonstration results indicate that leaching from untreated soil is significantly (>10x) greater from solidified/stabilized soil than treated material, except for highly soluble constituents (Cl
- , NO3 -2 ) or when constituents have similar equilibrium concentrations in both materials (As, Pb). Comparison between wet and dry environments show that while dry environments lead to lower COPC mass-based rates of leaching, the leaching concentrations may be higher due to lower liquid-to-solid ratios. The presented assessment methodology can be used to evaluate treatment effectiveness when both physical and chemical retention characteristics of the material are altered., (Copyright © 2020 Elsevier B.V. All rights reserved.)- Published
- 2021
- Full Text
- View/download PDF
34. A simple colorimetric experiment using mammalian cell culture to study metabolism.
- Author
-
Sharma K, Fizet KJ, Montgomery KR, Smeltzer NA, Sikorski MH, Brown KG, Beyke BJ, Burkhart RC, Lynn AN, and Grandinetti G
- Subjects
- Animals, CHO Cells, Colorimetry, Cricetulus, Humans, Mice, Universities, Biochemistry education, Cell Culture Techniques, Glycolysis, Oxidative Phosphorylation
- Abstract
The goal of this laboratory exercise is to give upper-level undergraduate students an introduction to sterile technique in mammalian cell culture and metabolism. The experiment can be completed within a 3-h lab period and can be performed either in conjunction with other biochemistry/metabolism experiments or used as a stand-alone experiment. In this experiment, students are tasked with relating the acidification of cell culture medium to metabolism in order to elucidate the mechanism of action for a compound. Students can relate their experimental results to topics covered on glycolysis and oxidative phosphorylation in upper-level biochemistry classes as well as gain valuable experience relating metabolism to drug discovery., (© 2020 International Union of Biochemistry and Molecular Biology.)
- Published
- 2021
- Full Text
- View/download PDF
35. Demonstration of the use of test results from the Leaching Environmental Assessment Framework (LEAF) to develop screening-level leaching assessments.
- Author
-
Garrabrants AC, Kosson DS, Brown KG, Fagnant DP Jr, Helms G, and Thorneloe SA
- Subjects
- Chromium, Construction Materials, Environmental Pollution, Soil, Soil Pollutants analysis
- Abstract
Environmental management often benefits from leaching assessment as a predictive tool for estimating constituent leaching from solid and waste materials. The Leaching Environmental Assessment Framework (LEAF) provides both validated tests methods for characterizing materials and a methodology for developing screening assessments based on material characterization results. The use of LEAF data in a screening-level environmental assessment approach is demonstrated through a hypothetical case study of copper/lead smelter soil remediation. The LEAF test methods characterize leaching behavior from a wide range of materials as either constituent liquid-solid partitioning as functions of pH and liquid-to-solid ratio (L/S) or as a rate of constituent mass transport. In this study, leaching characteristics of a contaminated smelter soil and the same soil treated by solidification/stabilization with Portland cement were compared to hypothetical environmental thresholds. Screening assessments were developed for total content, available content, and maximum concentrations over relevant pH domains and L/S ranges. Assessment ratios for barium, beryllium, and fluoride indicated that estimated leaching would be less than thresholds in both materials and these constituents were removed from further analysis. Similarly, chromium (in soil) and zinc (in solidified material) were screened from further analysis. For the remaining constituents, scenario-based assessment could refine estimated leaching concentrations by considering anticipated conditions of leaching scenario., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
36. Deep Learning of Spatiotemporal Filtering for Fast Super-Resolution Ultrasound Imaging.
- Author
-
Brown KG, Ghosh D, and Hoyt K
- Subjects
- Animals, Cell Line, Tumor, Contrast Media, Female, Mammary Neoplasms, Experimental diagnostic imaging, Mice, Mice, Nude, Microbubbles, Neural Networks, Computer, Deep Learning, Image Processing, Computer-Assisted methods, Signal Processing, Computer-Assisted, Ultrasonography methods
- Abstract
Super-resolution ultrasound (SR-US) imaging is a new technique that breaks the diffraction limit and allows visualization of microvascular structures down to tens of micrometers. The image processing methods for the spatiotemporal filtering needed in SR-US, such as singular value decomposition (SVD), are computationally burdensome and performed offline. Deep learning has been applied to many biomedical imaging problems, and trained neural networks have been shown to process an image in milliseconds. The goal of this study was to evaluate the effectiveness of deep learning to realize a spatiotemporal filter in the context of SR-US processing. A 3-D convolutional neural network (3DCNN) was trained on in vitro and in vivo data sets using SVD as ground truth in tissue clutter reduction. In vitro data were obtained from a tissue-mimicking flow phantom, and in vivo data were collected from murine tumors of breast cancer. Three training techniques were studied: training with in vitro data sets, training with in vivo data sets, and transfer learning with initial training on in vitro data sets followed by fine-tuning with in vivo data sets. The neural network trained with in vitro data sets followed by fine-tuning with in vivo data sets had the highest accuracy at 88.0%. The SR-US images produced with deep learning allowed visualization of vessels as small as [Formula: see text] in diameter, which is below the diffraction limit (wavelength of [Formula: see text] at 14 MHz). The performance of the 3DCNN was encouraging for real-time SR-US imaging with an average processing frame rate for in vivo data of 51 Hz with GPU acceleration.
- Published
- 2020
- Full Text
- View/download PDF
37. Sense and sensibility through confusing surgical practices during COVID-19 pandemic.
- Author
-
Koh CE, Brown KG, Fisher O, Steffens D, Yeo D, and McBride KE
- Subjects
- General Surgery standards, Humans, Practice Guidelines as Topic, Practice Patterns, Physicians', COVID-19 prevention & control, COVID-19 transmission, Surgical Procedures, Operative standards
- Published
- 2020
- Full Text
- View/download PDF
38. Risk to ecological resources following remediation can be due mainly to increased resource value of successful restoration: A case study from the Department of Energy's Hanford Site.
- Author
-
Burger J, Gochfeld M, Kosson DS, Brown KG, Salisbury JA, and Jeitner C
- Subjects
- Conservation of Natural Resources, Introduced Species, United States, Washington, Ecosystem, Environmental Restoration and Remediation
- Abstract
Many nations are faced with the need to remediate large contaminated sites following World War II, the Cold War, and abandoned industrial sites, and to return them to productive land uses. In the United States, the Department of Energy (DOE) has the largest cleanup challenge, and its Hanford Site in the state of Washington has the most extensive and most expensive cleanup task. Ideally, the risk to ecological resources on remediation sites is evaluated before, during, and after remediation, and the risk from, or damage to, ecological resources from contaminants should be lower following remediation. In this paper, we report the risk to ecological resources before, during, and as a consequence of remediation on contaminated units requiring cleanup, and then examine the causes for changes in risk by evaluating 56 cleanup evaluation units (EUs) at the Hanford Site. In this case, remediation includes a restoration phase. In general, the risk to ecological and eco-cultural resources is currently not discernible or low at most contaminated units, increases during remediation, and decreases thereafter. Remediation often causes physical disruption to ecosystems as it reduces the risk from exposure to contaminants. Most new remediation projects at the Hanford Site include ecological restoration. Ecological restoration results in the potential for the presence of higher quality resources after remediation than currently exists on these contaminated lands and facilities. Although counter-intuitive, our evaluation of the risk to ecological resources following remediation indicated that a significant percentage of units (61%) will be at increased risk in the post-remediation period. This increased risk is due to DOE's successful remediation and restoration that results in a higher percent of native vegetation and higher ecological value on the sites in the post-remediation period than before. These newly-created resources can then be at risk from post-remediation activities. Risks to these new higher quality resources include the potential for spread of invasive species and of noxious grasses used in previous cleanup actions, disruption of ecosystems (including those with state or federally listed species and unique ecosystems), compaction of soil, use of pesticides to control invasive species, and the eventual need for continued monitoring activities. Thus, by greatly improving the existing habitat and health of eco-receptors, and maintaining habitat corridors between high quality habitats, the ecological resources in the post-remediated units are at risk unless care is taken to protect them. Many of the negative effects of both remediation and future monitoring (or other future land uses) can be avoided by planning and management early in the remediation process. We suggest DOE and other agencies convene a panel of managers, remediation scientists, regulators, environmental and ecological scientists, Native Americans, economists, and the public to develop a generic list of performance metrics for the restoration phase of remediation, including evaluation of success, which could be applied across the DOE complex., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
39. CE: Opioid Use Disorder: Pathophysiology, Assessment, and Effective Interventions.
- Author
-
Brown KG and Capili B
- Subjects
- Cognitive Behavioral Therapy methods, Cognitive Behavioral Therapy standards, Humans, Opioid-Related Disorders psychology, Substance Withdrawal Syndrome prevention & control, Substance Withdrawal Syndrome therapy, Opioid-Related Disorders drug therapy, Opioid-Related Disorders physiopathology
- Abstract
Opioid use disorder (OUD) is a chronic, relapsing disease. Genetic variability, dysregulated stress system response, and history of opioid experimentation or escalating exposure all contribute to the likelihood of developing OUD, which produces complex brain changes that make it difficult to stop opioid use. Understanding the neurobiology of OUD helps nurses anticipate the behaviors of patients with OUD and approach them with empathy. Here, the authors discuss the pathophysiology of OUD, available screening tools, medical treatments, and behavioral interventions that have demonstrated efficacy in reducing substance use.
- Published
- 2020
- Full Text
- View/download PDF
40. Are trait impulsivity and exposure to cannabis or alcohol associated with the age of trajectory of cocaine use? A gender-specific dimensional analysis in humans with cocaine dependence diagnosis.
- Author
-
Butelman ER, Chen CY, Conybeare RA, Brown KG, Fry RS, Kimani R, Correa da Rosa J, Ott J, and Kreek MJ
- Subjects
- Adolescent, Adult, Female, Humans, Logistic Models, Male, Middle Aged, Young Adult, Alcohol Drinking epidemiology, Cocaine-Related Disorders epidemiology, Impulsive Behavior, Marijuana Abuse epidemiology
- Abstract
Cocaine use disorders (CUD) cause major morbidity and optimized prevention efforts are critical. It is unclear if trait impulsivity and exposure to cannabis or alcohol are associated with age trajectory of cocaine use (e.g., age of onset of heaviest use, or time of escalation), or with vulnerability to develop a CUD. This is an observational study with volunteers (≥ 18 years old), from a metropolitan area. The sample ( n = 1,010) included: n = 360 normal volunteers, n = 438 with cocaine dependence (CD) diagnoses, and n = 212 with other addictive diseases. Trait impulsivity was examined with BIS-11 scores. Maximal self-exposure to cannabis, alcohol, and cocaine were characterized dimensionally with Kreek-McHugh-Schluger-Kellogg (KMSK) scales. Time of escalation was defined as the interval between age of first use and age of onset of heaviest use. Onset of maximal use of cannabis (median age = 17) and alcohol (median age = 21) preceded that of cocaine (median age = 27), in volunteers with CD. Multivariate Cox regressions in volunteers with CD show that increasing self-exposure to cannabis was a predictor of earlier onset of heaviest use of cocaine. Also, more rapid time of escalation of alcohol was a predictor of more rapid time of escalation of cocaine. A multiple logistic regression shows that increasing self-exposure to cannabis or alcohol was a positive predictor of odds of CD diagnosis. Trait impulsivity and gender were not significant predictors in these multivariate analyses. This study shows that aspects of adolescent exposure to nonmedical cannabis and alcohol are predictors of early onset of CUD, and may be potentially targeted for prevention efforts. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
- Published
- 2020
- Full Text
- View/download PDF
41. In Reply: Growth of Lumbosacral Perineural (Tarlov) Cysts: A Natural History Analysis.
- Author
-
Mensah-Brown KG, Yang AI, and Welch WC
- Subjects
- Humans, Spine, Tarlov Cysts
- Published
- 2020
- Full Text
- View/download PDF
42. Inequalities in Meningioma Survival: Results from the National Cancer Database.
- Author
-
Yang AI, Mensah-Brown KG, Rinehart C, Fathy R, Hitti FL, Brant J, and Lee JYK
- Abstract
Background Meningiomas are the second most common primary tumors of the central nervous system. However, there is a paucity of literature examining how healthcare, demographic, and socioeconomic factors impact patient outcomes. Methods We conducted a retrospective study of 65,812 patients from the National Cancer Database (NCDB; 2004-2012) who received treatment for their meningioma. Univariate and multivariate analyses were performed with the overall five-year survival as the primary outcome, and the following factors: facility type, geography, housing area, patient insurance, sex, ethnicity, race, income, and education. The multivariate model was adjusted for patient age, co-morbidity, tumor size, behavior, and treatment strategy. Results Diagnosis and treatment at an academic/research program, private insurance, female sex, Hispanic ethnicity, and high school diploma conferred a survival advantage on both univariate and multivariate analyses. Conclusions Disparities in survival outcomes in patients with meningiomas exist across multiple healthcare, demographic, and socioeconomic factors. Additional research is needed to elucidate the genetic and environmental factors driving these inequalities., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2020, Yang et al.)
- Published
- 2020
- Full Text
- View/download PDF
43. A paradigm for protecting ecological resources following remediation as a function of future land use designations: a case study for the Department of Energy's Hanford Site.
- Author
-
Burger J, Gochfeld M, Kosson DS, Brown KG, Salisbury J, and Jeitner C
- Subjects
- Ecology, Government Agencies, Humans, Conservation of Natural Resources, Ecosystem, Environmental Monitoring
- Abstract
Since the late 1980s, there has been a US federal mandate to clean up contaminated sites remaining from the Second World War, the Cold War, and abandoned industries. One determinant of cleanup standards for remediation is future land use-how will the land be used and by whom? Land use decisions may be consensus documents developed by site owners, state and federal agencies, and local stakeholders. Often there are competing views and/or claims on how remediated sites should be used, including as open or green space. Large sites are likely to have more ecological heterogeneity within similar land use designations because of differences in climate, geology, topography, and history of human use. This paper uses the Department of Energy's (DOE) Hanford Site as a case study to examine how and whether future land use designations will protect species, species diversity, heterogeneity, and ecosystems once remediation is complete. The objective of this paper is to describe "future land use designations" on a large, complex site (DOE's Hanford Site) and to examine the following: (1) how future land use designations were made and have changed over time, (2) how land use designations included the value of ecological resources, (3) how risk evaluations of ecological resources from remediation were made, and (4) how future land use may affect the health and well-being of ecological resources on site in the post-remediation period. The paper provides a paradigm for integrating ecological protection into future land use designations such that rare and sensitive resources are protected throughout the process. The paradigm includes the following: (1) developing future land use designations, (2) defining resource levels (values), (3) relating resource levels to land use designations and management, (4) defining risk evaluations, (5) determining the likelihood that valuable resources will occur on each land use type after remediation, and (6) evaluating the potential risk to those resources that results from activities allowed under future land use designations. The paper discusses the importance of each step, the implications for protection of ecological resources, and the importance of land use designations in the assessment of risk to ecological resources from both continued monitoring and maintenance by DOE (or other land owners) and the activities permitted by the established future land use designations.
- Published
- 2020
- Full Text
- View/download PDF
44. Escalation of drug use in persons dually diagnosed with opioid and cocaine dependence: Gender comparison and dimensional predictors.
- Author
-
Butelman ER, Chen CY, Brown KG, and Kreek MJ
- Subjects
- Adolescent, Adult, Cocaine-Related Disorders psychology, Female, Forecasting, Humans, Male, Middle Aged, New York City epidemiology, Opioid-Related Disorders psychology, Sex Factors, Young Adult, Cocaine-Related Disorders diagnosis, Cocaine-Related Disorders epidemiology, Diagnostic and Statistical Manual of Mental Disorders, Opioid-Related Disorders diagnosis, Opioid-Related Disorders epidemiology
- Abstract
Background: Persons dually diagnosed with opioid and cocaine dependence (OD + CD) present a clinical challenge and are at risk of morbidity and mortality. The time of escalation of heroin and cocaine exposure in persons with OD + CD remain understudied, and the influence of gender and other variables have not been examined. This observational study focused on the time of escalation of heroin and cocaine in volunteers with OD + CD, examining gender and exposure to other drugs (e.g., cannabis or alcohol) as predictors. Ages of first use and of onset of heaviest use of each drug were collected (in whole years). Time of escalation was defined as the interval between age of first use and onset of heaviest use., Volunteers: sequentially ascertained adult volunteers recruited from the New York Metropolitan area, of which n = 297 were diagnosed with OD + CD., Methods: Instruments administered were the SCID-I diagnostic interview (DSM-IV criteria), BIS-11 impulsiveness scale, and KMSK scales, dimensional measures of maximal exposure to specific drugs., Results: In volunteers with OD + CD, ages of onset of heaviest use of cannabis (median age = 15) and alcohol (median age = 19) were in adolescence or emerging adulthood and preceded those for heroin and cocaine (median ages = 26 and 25, respectively). Maximal levels of cannabis and alcohol exposure were high, in volunteers with OD + CD. In adjusted Cox regressions, gender was not a significant predictor of time of heroin or cocaine escalation. However, more rapid time of alcohol escalation was a predictor of more rapid time of escalation of both heroin and cocaine, in volunteers with OD + CD., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
45. Interaction between spent fuel components and carbonate rocks.
- Author
-
Klein-BenDavid O, Harlavan Y, Levkov I, Teutsch N, Brown KG, Gruber C, and Ganor J
- Abstract
Deep geological repository is considered the internationally accepted method for spent fuel (SF) disposal. In countries where salt, clay, tuff and granite are unavailable at geologically suitable area, other rock types may come into consideration. In Israel, carbonate rocks make up a significant portion of the surface and subsurface lithologies, thus, low permeability carbonates were evaluated as possible host rocks for a repository, and for an interim storage facility. Sorption and retardation capacity of SF components to low permeability carbonate rocks were evaluated using their chemical simulants. Strontium and Cs represent components that may leach during interim storage, while U and Ce (as a simulant for redox-active actinides) represent components that may leach under repository conditions. Rocks from the Upper Cretaceous Mount Scopus Group were sampled from boreholes at the Yamin Plateau, Israel. Single point batch experiments were conducted with synthetic rainwater spiked with tracers and interacted with five rock types of various particle sizes at 25 °C. Results were evaluated using the LeachXS™-ORCHESTRA geochemical speciation and data management program. Cerium removal was found to be related to the HCO
3 - concentration in solution, where Ce precipitated as Ce2 (CO3 )3 ·XH2 O and as an amorphous carbonate phase. Removal of Cs and Sr was controlled by clays. No Sr co-precipitation as carbonate species was observed. Uranium was removed mainly by sorption onto solid organic matter, whereas clays had no significant role in U sorption. Iron-(hydr) oxides may have also played a role in U removal. Calculated partition coefficients for U, Cs, and Sr were in the order of 101 -102 mL/g. Grain size had no significant effect on the retention capacity of the studied rocks due to similar effective surface area. The current study indicates that a repository or an interim storage facility within carbonate rocks, would provide only partial isolation of radionuclides from the environment, hence, additional engineered barriers may be required., (Copyright © 2019. Published by Elsevier B.V.)- Published
- 2019
- Full Text
- View/download PDF
46. Evaluation of ecological resources at operating facilities at contaminated sites: The Department of Energy's Hanford Site as a case study.
- Author
-
Burger J, Gochfeld M, Kosson DS, Brown KG, Salisbury JA, and Jeitner C
- Subjects
- Environmental Restoration and Remediation, Humans, Risk, Conservation of Natural Resources, Ecology, Hazardous Waste Sites
- Abstract
The U.S. and other developed nations are faced with many contaminated sites remaining from World War II, the Cold War, and abandoned industries, that require remediation and restoration to allow future land uses with minimum acceptable risk to humans and ecological resources. For large Department of Energy (DOE) sites with massive remediation tasks remaining, it is important for managers to be able to assure regulators, Tribal Nations, and the public that human and ecological health are protected. Hanford Site has the largest and most expensive cleanup task within the DOE complex; cleanup will continue beyond 2090. Cleanup involves the use of operating facilities, which also may present a risk to humans or ecological resources. We present a brief description of a methodology to evaluate risks to ecological receptors at the Hanford Site from remaining remediation tasks, and evaluate the risk to ecological resources that operating facilities present currently, during active cleanup of these facilities, and during the post cleanup period. Operating facilities include current, active operations that are located on the site and aid in site cleanup, including both storage and treatment operations. At the Hanford Site, they include waste treatment plants, sludge basins, waste trenches, Central Waste Complex, storage facilities, and disposal facilities, among others. Risk ratings for ecological resources are highest during the remediation phase. Risk ratings for the operating facilities at the Hanford Site range from not discernible to medium currently, from not discernible (ND) to high during active cleanup, and from not discernible to medium following cleanup. The highest ratings are for the Waste Treatment and Immobilization Plant that is being constructed to stabilize radioactive and chemical wastes, and the Liquid Effluent Retention and Treatment Facility that removes and deactivates hazardous contaminants from waste water. Higher ratings in the post-cleanup period are largely due to restoration of ecological resources during cleanup, which increases the potential for injury (if these resources are harmed) because a site will then have higher quality resources after cleanup than it did before. Assessing the value of ecological resources, and determining potential consequences during active remediation and after remediation is essential for compliance with state and federal laws. Understanding the risks to ecological resources from now until clean-up is completed at these facilities is important because of the potential for ecological resources of high value to be degraded, and because cleanup completion is not expected until 2090 or later. The methodology can be applied to any contaminated site requiring a rapid method of assessing potential damages to ecological resources from proposed management actions., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
47. The costs of delaying remediation on human, ecological, and eco-cultural resources: Considerations for the Department of Energy: A methodological framework.
- Author
-
Burger J, Gochfeld M, Kosson DS, Brown KG, Bliss LS, Bunn A, Clarke JH, Mayer HJ, and Salisbury JA
- Subjects
- Conservation of Natural Resources economics, Environmental Restoration and Remediation economics, Time Factors, United States, Washington, Conservation of Natural Resources methods, Cost-Benefit Analysis, Environmental Restoration and Remediation methods
- Abstract
Remediation and restoration of the Nation's nuclear legacy of radiological and chemical contaminated areas is an ongoing and costly challenge for the U.S. Department of Energy (DOE). For large sites, such as the Hanford and Savannah River Sites, successful remediation involves complex decisions related to remedies, end-states, timing, and sequencing of cleanup of separate and related contaminated units within a site. Hanford Site cannot clean up every unit simultaneously due to limits in funding, personnel, and technology. This paper addresses one of the major considerations - the consequences of delaying remediation of a unit on different receptors (e.g. people, ecological, and eco-cultural resources), using the DOE Hanford Site as a case study. We develop a list of attributes that managers should consider for successful remediation, examine how delaying remediation could affect workers, the public and ecological resources (including water resources), and use some examples to illustrate potential effects of delays. The factors to consider when deciding whether and how long to delay remediation of a unit include personnel, information and data, funding, equipment, structural integrity, contaminant source, and resource vulnerability. Each of these factors affects receptors differently. Any remediation task may be dependent on other remediation projects, on the availability of transport, containers, interim storage and ultimate disposition decisions, or the availability of trained personnel. Delaying remediation may have consequences for people (e.g. workers, site neighbors), plants, animals, ecosystems, and eco-cultural resources (i.e. those cultural values that depend upon ecological resources). The risks, benefits, and uncertainties for evaluating the consequences of delaying remediation are described and discussed. Assessing the advantages and disadvantages of delaying remediation is important for health professionals, ecologists, resource trustees, regulators, Tribal members, recreationists, fishermen, hunters, conservationists, and a wide range of other stakeholders., (Copyright © 2018. Published by Elsevier B.V.)
- Published
- 2019
- Full Text
- View/download PDF
48. Electroencephalographic Response to Deep Hypothermic Circulatory Arrest in Neonatal Swine and Humans.
- Author
-
Mavroudis CD, Mensah-Brown KG, Ko TS, Boorady TW, Massey SL, Abend NS, Nicolson SC, Morgan RW, Mascio CE, Gaynor JW, Kilbaugh TJ, and Licht DJ
- Subjects
- Animals, Animals, Newborn, Cardiopulmonary Bypass methods, Cohort Studies, Female, Humans, Infant, Newborn, Male, Swine, Circulatory Arrest, Deep Hypothermia Induced, Electroencephalography
- Abstract
Background: Piglets are used to study neurologic effects of deep hypothermic circulatory arrest (DHCA), but no studies have compared human and swine electroencephalogram (EEG) responses to DHCA. The importance of isoelectricity before circulatory arrest is not fully known in neonates. We compared the EEG response to DHCA in human neonates and piglets., Methods: We recorded 2 channel, left and right centroparietal, subdermal EEG in 10 neonatal patients undergoing operations involving DHCA and 10 neonatal piglets that were placed on cardiopulmonary bypass and underwent a simulated procedure using DHCA. EEG waveforms were analyzed for the presence and extent of burst suppression and isoelectricity by automated moving window analysis. The patients were monitored with 16-channel array EEG for 48 hours postoperatively and underwent postoperative brain magnetic resonance imaging., Results: After induction of anesthesia, humans and piglets both displayed slowing or brief suppression, then mild burst suppression, and then severe burst suppression during cooling. All piglets subsequently achieved isoelectricity at 22.4° ± 6.9°C, whereas only 1 human did at 20.2°C. Piglets and humans emerged from severe, mild, and then brief suppression patterns during rewarming. Among the patients, there were no seizures during postoperative monitoring and 1 instance of increased white matter injury on postoperative magnetic resonance imaging., Conclusions: Our data suggest that current cooling strategies may not be sufficient to eliminate all EEG activity before circulatory arrest in humans but are sufficient in swine. This important difference between the swine and human response to DHCA should be considered when using this model., (Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
49. Which mental disorders are associated with the greatest impairment in functioning?
- Author
-
Edlund MJ, Wang J, Brown KG, Forman-Hoffman VL, Calvin SL, Hedden SL, and Bose J
- Subjects
- Adolescent, Adult, Disability Evaluation, Female, Health Surveys, Humans, Male, Middle Aged, United States epidemiology, Young Adult, Mental Disorders complications, Mental Disorders epidemiology, Severity of Illness Index
- Abstract
Objective: The objective of this study is to estimate the comparative associations of mental disorders with three measures of functional impairment: the Global Assessment of Functioning (GAF); the number of days in the past 12 months of total inability to work or carry out normal activities because of emotions, nerves, or mental health (i.e., days out of role); and a modified version of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0)., Methods: Secondary data analysis of the linked Mental Health Surveillance Study and the National Survey on Drug Use and Health (n = 5653), nationally representative population surveys conducted in the United States. Generalized linear models assessed the independent effects of mental disorders on each measure of functional impairment, controlling for mental disorder comorbidity, physical health disorders, and sociodemographic factors., Results: The results varied across measures of functional impairment. However, mood disorders generally tended to be associated with the greatest functional impairment, anxiety disorders with intermediate impairment, and substance use disorders with the least impairment. All 15 disorders were significantly associated with the GAF score in multiple regression models, eight disorders were significantly associated with the WHODAS score, and three disorders were significantly associated with days out of role., Conclusions: Our results highlight the value of complementary measures of functional impairment.
- Published
- 2018
- Full Text
- View/download PDF
50. Cerebral mitochondrial dysfunction associated with deep hypothermic circulatory arrest in neonatal swine.
- Author
-
Mavroudis CD, Karlsson M, Ko T, Hefti M, Gentile JI, Morgan RW, Plyler R, Mensah-Brown KG, Boorady TW, Melchior RW, Rosenthal TM, Shade BC, Schiavo KL, Nicolson SC, Spray TL, Sutton RM, Berg RA, Licht DJ, Gaynor JW, and Kilbaugh TJ
- Subjects
- Animals, Animals, Newborn, Cardiopulmonary Bypass, Cell Respiration physiology, Energy Metabolism physiology, Female, Hemodynamics physiology, Microdialysis methods, Reactive Oxygen Species metabolism, Sus scrofa, Cerebral Cortex metabolism, Circulatory Arrest, Deep Hypothermia Induced, Mitochondria physiology
- Abstract
Objectives: Controversy remains regarding the use of deep hypothermic circulatory arrest (DHCA) in neonatal cardiac surgery. Alterations in cerebral mitochondrial bioenergetics are thought to contribute to ischaemia-reperfusion injury in DHCA. The purpose of this study was to compare cerebral mitochondrial bioenergetics for DHCA with deep hypothermic continuous perfusion using a neonatal swine model., Methods: Twenty-four piglets (mean weight 3.8 kg) were placed on cardiopulmonary bypass (CPB): 10 underwent 40-min DHCA, following cooling to 18°C, 10 underwent 40 min DHCA and 10 remained at deep hypothermia for 40 min; animals were subsequently rewarmed to normothermia. 4 remained on normothermic CPB throughout. Fresh brain tissue was harvested while on CPB and assessed for mitochondrial respiration and reactive oxygen species generation. Cerebral microdialysis samples were collected throughout the analysis., Results: DHCA animals had significantly decreased mitochondrial complex I respiration, maximal oxidative phosphorylation, respiratory control ratio and significantly increased mitochondrial reactive oxygen species (P < 0.05 for all). DHCA animals also had significantly increased cerebral microdialysis indicators of cerebral ischaemia (lactate/pyruvate ratio) and neuronal death (glycerol) during and after rewarming., Conclusions: DHCA is associated with disruption of mitochondrial bioenergetics compared with deep hypothermic continuous perfusion. Preserving mitochondrial health may mitigate brain injury in cardiac surgical patients. Further studies are needed to better understand the mechanisms of neurological injury in neonatal cardiac surgery and correlate mitochondrial dysfunction with neurological outcomes.
- Published
- 2018
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.