6 results on '"Christian, David"'
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2. Heavy metals removal from mine runoff using compost bioreactors.
- Author
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Christian, David, Wong, Edmund, Crawford, Ronald L., Cheng, I. Francis, and Hess, Thomas F.
- Subjects
BIOREACTORS ,SULFATES ,BACTERIA ,METALS - Abstract
Permeable bioreactors have gained both research and management attention as viable methods for treating mine runoff waters. We examined the operation of a field-scale bioreactor (containing mixed compost, straw and gravel) for treatment of runoff from the Mother Load (ML) mine in northern Idaho, U.S. and compared it to an experimental laboratory-scale reactor, containing a similar matrix and treating similar mine runoff water. In general both reactors were efficient in removing most of the metals assayed, Al, As, Cd, Fe, Ni, Pb and Zn, with the exception of Mn. Both systems showed evidence of bacterial-mediated sulphate reduction and concomitant metal sulphide complexes. However, the experimental laboratory bioreactor showed greater proportions of immobile metals reductions than did the ML bioreactor, presumably due to the greater action of sulphate-reducing bacteria. The major metal removal mechanism in the ML bioreactor was surmised to be adsorption. Differences in metal removal mechanisms between the reactors were hypothesized to be due to fluctuating hydraulic residence times at the ML site, in turn, due to unregulated runoff flow. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
3. New homes can be key to neighborhood revitalization.
- Author
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Christian, David
- Subjects
TOURISM ,SOCIAL classes ,UPPER class ,NEIGHBORHOODS ,COMMUNITY life - Abstract
Focuses on a series of forces that are at work in Stop Six that could enhance the area as a cultural and commercial destination to a middle-to-upper class community in Texas. Location of Stop Six; Factors involved in neighborhood revitalization; Businesses enjoyed by the Stop Six area; Outstanding community assets possessed by the Stop Six area.
- Published
- 2003
4. Impact of Frailty on Emergency Department Encounters for Cardiovascular Disease: A Retrospective Cohort Study.
- Author
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Sokhal BS, Matetić A, Abhishek A, Banerjee A, Partington R, Roddy E, Rashid M, Mallen CD, and Mamas MA
- Subjects
- Humans, United States epidemiology, Retrospective Studies, Risk Factors, Emergency Service, Hospital, Cardiovascular Diseases epidemiology, Cardiovascular Diseases complications, Frailty complications, Hemorrhagic Stroke, Myocardial Infarction, Heart Failure complications, Atrial Fibrillation complications, Ischemic Stroke complications
- Abstract
Data are limited on whether the causes of emergency department (ED) encounters for cardiovascular diseases (CVDs) and associated clinical outcomes vary by frailty status. Using the United States Nationwide ED Sample, selected CVD encounters (acute myocardial infarction [AMI], ischemic stroke, atrial fibrillation [AF], heart failure [HF], pulmonary embolism, cardiac arrest, and hemorrhagic stroke) were stratified by hospital frailty risk score (HFRS). Logistic regression was used to determine the adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of ED mortality among the different frailty groups. A total of 8,577,028 selected CVD ED encounters were included. A total of 5,120,843 (59.7%) had a low HFRS (<5), 3,041,699 (35.5%) had an intermediate HFRS (5 to 15), and 414,485 (4.8%) had a high HFRS (>15). Ischemic stroke was the most common reason for the encounter in the high HFRS group (66.9%), followed by hemorrhagic stroke (11.7%) and AMI (7.2%). For the low HFRS group, AF was the most common reason for the encounter (30.2%), followed by AMI (23.6%) and HF (16.8%). Compared with the low-risk group, high-risk patients had a decreased ED mortality and an increased overall mortality across most CVD encounters (p <0.001). The strongest association with overall mortality was observed among patients with a high HFRS admitted for AF (aOR 27.14, 95% CI 25.03 to 29.43) and HF (aOR 13.71, 95% CI 12.95 to 14.51) compared with their low-risk counterparts. In conclusion, patients presenting to the ED with acute CVD have a significant frailty burden, with different patterns of CVD according to frailty status. Frailty is associated with an increased all-cause mortality in patients for most CVD encounters., Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
5. Management of Chondral Lesions of the Knee: Analysis of Trends and Short-Term Complications Using the National Surgical Quality Improvement Program Database.
- Author
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Gowd AK, Cvetanovich GL, Liu JN, Christian DR, Cabarcas BC, Redondo ML, Verma NN, Yanke AB, and Cole BJ
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Cartilage Diseases diagnosis, Cartilage, Articular diagnostic imaging, Female, Follow-Up Studies, Humans, Incidence, Knee Joint diagnostic imaging, Male, Middle Aged, Retrospective Studies, Time Factors, Transplantation, Autologous, United States epidemiology, Young Adult, Bone Transplantation methods, Cartilage Diseases surgery, Cartilage, Articular surgery, Knee Joint surgery, Orthopedic Procedures standards, Postoperative Complications epidemiology, Quality Improvement
- Abstract
Purpose: To provide updated surgical trends of cartilage procedures differentiated by the classic groups of palliative, repair, and restorative modalities., Methods: The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2010-2016 for the following cartilage procedures: chondroplasty, microfracture, arthroscopic osteochondral autograft or allograft transplantation, open osteochondral autograft or allograft transplantation, and autologous chondrocyte implantation. Demographic variables and short-term (30-day) complications were analyzed with 1-way analysis of variance and post hoc analysis. Linear regression analysis was performed to analyze trends over time., Results: A total of 15,609 procedures performed between 2010 and 2016 were analyzed. On average, 342.2 ± 27.9 cartilage procedures were performed per 100,000 operations. There was a linear increase in the management of overall cartilage procedures per 100,000 operations (P = .002). There were also linear increases in arthroscopic osteochondral autograft transplantation, arthroscopic osteochondral allograft transplantation, open osteochondral autograft transplantation, open osteochondral allograft transplantation, and autologous chondrocyte implantation (P < .001, P = .037, P = .001, P = .006, and P = .002, respectively). Meniscectomy was the most frequently performed concomitant procedure (9.7%-64.2% of cases). Chondroplasty and microfracture showed no change in frequency over time (P = .140 and P = .720, respectively). The overall complication rate was 2.1% for chondroplasty, 1.4% for microfracture, 1.8% for arthroscopic osteochondral autograft transplantation, 1.0% for arthroscopic osteochondral allograft transplantation, 1.4% for open osteochondral autograft transplantation, 1.1% for open osteochondral allograft transplantation, and 0.75% for autologous chondrocyte implantation. Deep vein thrombosis was the most common complication, occurring in 0.4% to 1.0% of cases. No statistically significant difference was found in complication rates between procedures (P = .105)., Conclusions: Cartilage restoration is becoming an increasingly popular modality to address chondral defects. Minimal complication rates suggest that these procedures may be safely performed concomitantly with other interventions., Level of Evidence: Level IV, retrospective database analysis., (Copyright © 2019 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
- Full Text
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6. Physician Extenders in Hand Surgery: The Patient's Perspective.
- Author
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Manning BT, Bohl DD, Luchetti TJ, Christian DR, Fernandez JJ, Cohen MS, and Wysocki RW
- Subjects
- Adult, Clinical Competence, Female, Hand surgery, Humans, Insurance, Health, Reimbursement, Male, Professional Role, Quality of Health Care, Surveys and Questionnaires, United States, Nurse Practitioners, Orthopedics, Patient Satisfaction, Physician Assistants
- Abstract
Background: Physician extenders, such as physician assistants (PAs) and nurse practitioners (NPs), have been incorporated into health systems in response to the rising demand for care. There is a paucity of literature regarding patient perspectives toward physician extenders in hand surgery., Methods: We anonymously surveyed 939 consecutive new patients before their clinic visit. Our questionnaire assessed patient perspectives toward physician extenders, including optimal scope of practice, the effect of the extender when choosing a hand surgeon, and pay equity for the same clinical services., Results: Of 939 patients, 784 (84%) responded: 54% were male and 46% were female with a mean age of 44.1 years. Most (65%) patients consider the extender's training background when choosing a hand surgeon, with 31% of all patients considering PAs to have higher training than NPs and 17% the reverse. Patients responded that certain services should be physician-provided, including determining the need for advanced imaging (eg, magnetic resonance imaging), follow-up for abnormal diagnostics, and new patient visits. Patients were amenable to services being extender-provided, including minor in-office procedures, preoperative teaching, and postoperative clinic visits. Patients lacked a consensus toward reimbursement equity for hand surgeons and physician extenders providing the same clinical services., Conclusions: Our data suggest that patients presenting to a hand surgeon are comfortable receiving direct care from a physician extender in many, but not all, circumstances. Hand surgeons can use these data when deciding how to use extenders to optimize patient satisfaction and practice efficiency as health care systems become increasingly consumer-focused and value-based.
- Published
- 2019
- Full Text
- View/download PDF
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