Search

The pterional approach has traditionally been employed for managing middle cerebral artery (MCA) aneurysms. With potential benefits like reduced surgical morbidity and improved postoperative recovery, the lateral supraorbital approach (LSO) should be considered individually based on aneurysm morphology, location and patient-specific variations of the MCA anatomy, which requires considerable technical expertise traditionally acquired through years of experience. The goal of this study was the development and evaluation of a novel phantom simulator in the context of clinical decision-making in the managmement of MCA aneurysms. For this purpose, high-fidelity simulators inclusive of MCA models with identical M1- and bifurcation aneurysms were manufactured employing 3D reconstruction techniques, additive manufacturing and rheological testings. Medical students, neurosurgical residents, and seasoned neurosurgeons (n = 22) tested and evaluated both approaches. Participants' performances and progress over time were assessed based on objective metrics. The simulator received positive ratings in face and content validity, with mean scores of 4.9 out of 5, respectively. Objective evaluation demonstrated the model's efficacy as a practical training tool, particularly among inexperienced participants. While requiring more technical expertise, results of the comparative analysis suggest that the LSO approach can improve clipping precision and outcome particularly in patients with shorter than average M1-segments. In conclusion, the employed methodology allowed a direct comparison of the pterional and LSO approaches, revealing comparable success rates via the LSO approach while reducing operation time and complication rate. Future research should aim to establish simulators in the context of clinical decision making. [ABSTRACT FROM AUTHOR]

Intracranial aneurysms (IAs) located in the anterior and posterior circulations of the Circle of Willis present differential rupture risks. This study aimed to compare the rupture risk and clinical outcomes of anterior communicating artery aneurysms (AcomA) and basilar tip aneurysms (BAs); two IA types located along the midline within the Circle of Willis. We retrospectively collected data from 1026 patients presenting with saccular IAs. Only AcomA and BAs with a 3D angiography were included. Out of 186 included IAs, a cohort of 32 BAs was matched with AcomA based on the patients' pre-existing conditions and morphological parameters of IAs. Clinical outcomes, including rupture risk, hydrocephalus development, vasospasm incidence, and patients' outcome, were compared. The analysis revealed no significant difference in rupture risk, development of hydrocephalus, need for ventricular drainage, or vasospasm incidence between the matched AcomA and BA cohorts. Furthermore, the clinical outcomes post-rupture did not significantly differ between the two groups, except for a higher Fisher Grade associated with BAs. Once accounting for morphological and patient factors, the rupture risk between AcomA and BAs is comparable. These findings underscore the importance of tailored management strategies for specific IA types and suggest that further investigations should focus on the role of individual patient and aneurysm characteristics in IA rupture risk and clinical outcomes. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is a chronic, metabolic illness characterized by an elevation of blood sugar levels. Patients with diabetes show changes in hematological indices. The study aimed to determine hematological indices, ESR, CRP, blood pressure (BP), and weight and their relationship with a fasting blood sugar (FBS) level and different variables in diabetic mellitus patients (DM) compared with healthy control (HC). A total of 202 participants (102 DM group and 100 HC group) were selected randomly. Data were collected using a questionnaire. Blood samples were collected from different places and investigated in Zain Medical Laboratories in Ibb City, Yemen (September 2022 to May 2023). GraphPad Prim was used to analyze the results. P-value ≤ 0.05 was considered statistically significant. The mean and standard deviation of age, weight, gender, residence, marital status, education levels, economic status, regular exercise, following a strict diet, and family history of diabetes revealed significant differences between DM and HC groups (P < 0.0001, P = 0001, P = 0.0027, P = 0.0002, P < 0.0001, P < 0.0001, P = 0.0002, P = 0.0011, P < 0.0001 and P = 0.0001, respectively). FBS results, systolic and diastolic BP, MCV, WBCs, monocytes, eosinophils, and platelets displayed significant differences between both groups (P < 0.0001, P < 0.0001 and P = 0.0404, P = 0.0191, P < 0.0001, P = 0.0253, P < 0.0001, and P = 0.0229, respectively). ESR exhibited statistical significance (P < 0.0001), while CRP displayed no significance. A Pearson's correlation showed that weight, Hb, RBCs, PCV, and WBCs were statistically negatively correlated with FBS whereas other hematological indices showed no correlation with FBS. In conclusion, DM patients had relatively higher levels of MCV, WBCs, eosinophils, platelets and ESR than the control group. [ABSTRACT FROM AUTHOR]

Objective: To compare the diagnostic accuracy of diffusion-weighted (DW)-MRI with b-values of 50 s/mm2 and 800 s/mm2 for the detection of bone marrow metastases in children and young adults with solid malignancies. Methods: In an institutional review board-approved prospective study, we performed 51 whole-body DW-MRI scans in 19 children and young adults (14 males, 5 females; age range: 1–25 years) with metastasized cancers before (n = 19 scans) and after (n = 32 scans) chemotherapy. Two readers determined the presence of focal bone marrow lesions in 10 anatomical areas. A third reader measured ADC and SNR of focal lesions and normal marrow. Simultaneously acquired 18F-FDG-PET scans served as the standard of reference. Data of b = 50 s/mm2 and 800 s/mm2 images were compared with the Wilcoxon signed-rank test. Inter-reader agreement was evaluated with weighted kappa statistics. Results: The SNR of bone marrow metastases was significantly higher compared to normal bone marrow on b = 50 s/mm2 (mean ± SD: 978.436 ± 1239.436 vs. 108.881 ± 109.813, p < 0.001) and b = 800 s/mm2 DW-MRI (499.638 ± 612.721 vs. 86.280 ± 89.120; p < 0.001). On 30 out of 32 post-treatment DW-MRI scans, reconverted marrow demonstrated low signal with low ADC values (0.385 × 10−3 ± 0.168 × 10−3mm2/s). The same number of metastases (556/588; 94.6%; p > 0.99) was detected on b = 50 s/mm2 and 800 s/mm2 images. However, both normal marrow and metastases exhibited low signals on ADC maps, limiting the ability to delineate metastases. The inter-reader agreement was substantial, with a weighted kappa of 0.783 and 0.778, respectively. Conclusion: Bone marrow metastases in children and young adults can be equally well detected on b = 50 s/mm2 and 800 s/mm2 images, but ADC values can be misleading. [ABSTRACT FROM AUTHOR]

Purpose: To assess and compare the diagnostic accuracy of whole-body (WB) DW-MRI with 2-[18F]FDG PET for staging and treatment monitoring of children with Langerhans cell histiocytosis (LCH). Methods: Twenty-three children with LCH underwent 2-[18F]FDG PET and WB DW-MRI at baseline. Two nuclear medicine physicians and two radiologists independently assessed presence/absence of tumors in 8 anatomical areas. Sixteen children also performed 2-[18F]FDG PET and WB DW-MRI at follow-up. One radiologist and one nuclear medicine physician revised follow-up scans and collected changes in tumor apparent diffusion (ADC) and standardized uptake values (SUV) before and after therapy in all detectable lesions. 2-[18F]FDG PET results were considered the standard of reference for tumor detection and evaluation of treatment response according to Lugano criteria. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of WB DW-MRI at baseline were calculated, and the 95% confidence intervals were estimated by using the Clopper-Pearson (exact) method; changes in tumor SUVs and ADC were compared using a Mann–Whitney U test. Agreement between reviewers was assessed with a Cohen's weighted kappa coefficient. Analyses were conducted using SAS software version 9.4. Results: Agreement between reviewers was perfect (kappa coefficient = 1) for all analyzed regions but spine and neck (kappa coefficient = 0.89 and 0.83, respectively) for 2-[18F]FDG PET images, and abdomen and pelvis (kappa coefficient = 0.65 and 0.88, respectively) for WB DW-MRI. Sensitivity and specificity were 95.5% and 100% for WB DW-MRI compared to 2-[18F]FDG PET. Pre to post-treatment changes in SUVratio and ADCmean were inversely correlated for all lesions (r: -0.27, p = 0·06) and significantly different between responders and non-responders to chemotherapy (p = 0.0006 and p = 0·003 for SUVratio and ADCmean, respectively). Conclusion: Our study showed that WB DW-MRI has similar accuracy to 2-[18F]FDG PET for staging and treatment monitoring of LCH in children. While 2-[18F]FDG PET remains an approved radiological examination for assessing metabolically active disease, WB DW-MRI could be considered as an alternative approach without radiation exposure. The combination of both modalities might have advantages over either approach alone. [ABSTRACT FROM AUTHOR]

On the battlefield, early detection of armored vehicles can have a positive effect. Because according to this issue, timely and appropriate reactions can be done. The purpose of this study is to achieve the required algorithm in the vehicle control system by considering the car sensor vision, which is necessary to identify and determine the equipment needed to control the military drone based on car sensor vision. Today, the use of wireless networks, especially inter-vehicle wireless networks, in military applications is inevitable. Therefore, in the first step of this research, a new method has been proposed to control and steer unmanned vehicles based on car vision. In the proposed method, two 180-degree panoramic cameras with horizontal vision are used from the recorded images. The simulation results of the proposed method show increased accuracy and reduced implementation cost compared to using LIDAR and RADAR technologies. In the second step, a new approach is introduced to identify four common classes of armored vehicles (tanks, personnel carriers, firing tanks, and military vehicles) that are more likely to be present on battlefields. For this purpose, the latest image processing methods, which is deep learning, have been used. The results of the simulation of the proposed approach show the high accuracy of the proposed approach in detecting armored vehicles in a short time. In the third step of this research, a new method has been proposed to increase the connection of wireless networks. In the proposed method, queue theory is used and the results of the simulation of the proposed method show the high efficiency of the method. As a result, accurate and fast detection with unique features makes the users of the system superior. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the clinical utility of selective magnetic resonance neurography-(MRN)-guided anterior femoral cutaneous nerve (AFCN) blocks for diagnosing anterior thigh neuralgia. Materials and methods: Following institutional review board approval and informed consent, participants with intractable anterior thigh pain and clinically suspected AFCN neuralgia were included. AFCN blocks were performed under MRN guidance using an anterior groin approach along the medial sartorius muscle margin. Outcome variables included AFCN identification on MRN, technical success of perineural drug delivery, rate of AFCN anesthesia, complications, total procedure time, patient-reported procedural experiences, rate of positive diagnostic AFCN blocks, and positive subsequent treatment rate. Results: Eighteen MRN-guided AFCN blocks (six unilateral and six bilateral blocks) were performed in 12 participants (6 women; age, 49 (30–65) years). Successful MRN identified the AFCN, successful perineural drug delivery, and AFCN anesthesia was achieved in all thighs. No complications occurred. The total procedure time was 19 (10–28) min. Patient satisfaction and experience were high without adverse MRI effects. AFCN blocks identified the AFCN as the symptom generator in 16/18 (89%) cases, followed by 14/16 (88%) successful treatments. Conclusion: Our results suggest that selective MR neurography-guided AFCN blocks effectively diagnose anterior femoral cutaneous neuralgia and are well-tolerated. [ABSTRACT FROM AUTHOR]

The purpose of our study was to investigate if vascular injury in immature epiphyses affects cartilage repair outcomes of matrix-associated stem cell implants (MASI). Porcine bone marrow mesenchymal stromal stem cells (BMSCs) suspended in a fibrin glue scaffold were implanted into 24 full-thickness cartilage defects (5 mm ø) of the bilateral distal femur of six Göttingen minipigs (n = 12 defects in 6 knee joints of 3 immature pigs; age 3.5–4 months; n = 12 defects in 6 knee joints of 3 mature control pigs; age, 21–28 months). All pigs underwent magnetic resonance imaging (MRI) at 2, 4, 12 (n = 24 defects), and 24 weeks (n = 12 defects). After the last imaging study, pigs were sacrificed, joints explanted and evaluated with VEGF, H&E, van Gieson, Mallory, and Safranin O stains. Results of mature and immature cartilage groups were compared using the Wilcoxon signed-rank test. Quantitative scores for subchondral edema at 2 weeks were correlated with quantitative scores for cartilage repair (MOCART score and ICRS score) at 12 weeks as well as Pineda scores at end of the study, using linear regression analysis. On serial MRIs, mature joints demonstrated progressive healing of cartilage defects while immature joints demonstrated incomplete healing and damage of the subchondral bone. The MOCART score at 12 weeks was significantly higher for mature joints (79.583 ± 7.216) compared to immature joints (30.416 ± 10.543, p = 0.002). Immature cartilage demonstrated abundant microvessels while mature cartilage did not contain microvessels. Accordingly, cartilage defects in immature joints showed a significantly higher number of disrupted microvessels, subchondral edema, and angiogenesis compared to mature cartilage. Quantitative scores for subchondral edema at 2 weeks were negatively correlated with MOCART scores (r = − 0.861) and ICRS scores (r = − 0.901) at 12 weeks and positively correlated with Pineda scores at the end of the study (r = 0.782). Injury of epiphyseal blood vessels in immature joints leads to subchondral bone defects and limits cartilage repair after MASI. [ABSTRACT FROM AUTHOR]

Objectives: To compare the diagnostic accuracy of 2-[18F]fluoro-2-deoxy-D-glucose-enhanced positron emission tomography (2-[18F]FDG-PET) and diffusion-weighted magnetic resonance imaging (DW-MRI) for the detection of bone marrow metastases in children and young adults with solid malignancies.Methods: In this cross-sectional single-center institutional review board-approved study, we investigated twenty-three children and young adults (mean age, 16.8 years ± 5.1 [standard deviation]; age range, 7-25 years; 16 males, 7 females) with 925 bone marrow metastases who underwent 66 simultaneous 2-[18F]FDG-PET and DW-MRI scans including 23 baseline scans and 43 follow-up scans after chemotherapy between May 2015 and July 2020. Four reviewers evaluated all foci of bone marrow metastasis on 2-[18F]FDG-PET and DW-MRI to assess concordance and measured the tumor-to-bone marrow contrast. Results were assessed with a one-sample Wilcoxon test and generalized estimation equation. Bone marrow biopsies and follow-up imaging served as the standard of reference.Results: The reviewers detected 884 (884/925, 95.5%) bone marrow metastases on 2-[18F]FDG-PET and 893 (893/925, 96.5%) bone marrow metastases on DW-MRI. We found different "blind spots" for 2-[18F]FDG-PET and MRI: 2-[18F]FDG-PET missed subcentimeter lesions while DW-MRI missed lesions in small bones. Sensitivity and specificity were 91.0% and 100% for 18F-FDG-PET, 89.1% and 100.0% for DW-MRI, and 100.0% and 100.0% for combined modalities, respectively. The diagnostic accuracy of combined 2-[18F]FDG-PET/MRI (100.0%) was significantly higher compared to either 2-[18F]FDG-PET (96.9%, p < 0.001) or DW-MRI (96.3%, p < 0.001).Conclusions: Both 2-[18F]FDG-PET and DW-MRI can miss bone marrow metastases. The combination of both imaging techniques detected significantly more lesions than either technique alone.Key Points: • DW-MRI and 2-[18F]FDG-PET have different strengths and limitations for the detection of bone marrow metastases in children and young adults with solid tumors. • Both modalities can miss bone marrow metastases, although the "blind spot" of each modality is different. • A combined PET/MR imaging approach will achieve maximum sensitivity and specificity for the detection of bone marrow metastases in children with solid tumors. [ABSTRACT FROM AUTHOR]

Low carbon steel is widely used in industry due to its excellent elastoplastic behavior with the mechanism of damage accumulation during severe plastic deformation processes which lead to increase strength resistance. In this study, the strain locus of the failure is predicted based on the stress triaxiality and Lode angle-dependent damage model by considering damage evolution during the process. Therefore, by performing various tests for several stress states and modeling the load paths related to damage accumulations, the coefficients of the modified Mohr–Coulomb damage model and Johnson–Cook are determined. According to results achieved among the test with good accuracy, the predictor locus of the failure strain is illustrated. Then, using the determined coefficients, the steel damage evolution is investigated during the process of Equal Channel Angular Extrusion (ECAE). It is shown that the damage accumulation during the ECAE process in a die with respectively internal and external angles of 90 and 30 degrees grows from the region closer to the internal angle as reaches a maximum value in central regions. Also, the amount of damage in vicinity of the outer angle is extremely reduced. According to experiments, the steel does resist fracture events after the ECAE process. [ABSTRACT FROM AUTHOR]

Gadolinium chelates have been used as standard contrast agents for clinical MRI for several decades. However, several investigators recently reported that rare Earth metals such as gadolinium are deposited in the brain for months or years. This is particularly concerning for children, whose developing brain is more vulnerable to exogenous toxins compared to adults. Therefore, a search is under way for alternative MR imaging biomarkers. The United States Food and Drug Administration (FDA)-approved iron supplement ferumoxytol can solve this unmet clinical need: ferumoxytol consists of iron oxide nanoparticles that can be detected with MRI and provide significant T1- and T2-signal enhancement of vessels and soft tissues. Several investigators including our research group have started to use ferumoxytol off-label as a new contrast agent for MRI. This article reviews the existing literature on the biodistribution of ferumoxytol in children and compares the diagnostic accuracy of ferumoxytol- and gadolinium-chelate-enhanced MRI. Iron oxide nanoparticles represent a promising new class of contrast agents for pediatric MRI that can be metabolized and are not deposited in the brain. [ABSTRACT FROM AUTHOR]

Background: The diagnosis of joint infiltration by a malignant bone tumor affects surgical management. The specificity of standard magnetic resonance imaging (MRI) for diagnosing joint infiltration is limited. During our MRI evaluations with ferumoxytol nanoparticles of pediatric and young adult patients with bone sarcomas, we observed a surprising marked T1 enhancement of joint and pleural effusions in some patients but not in others.Objective: To evaluate if nanoparticle extravasation differed between joints and pleura with and without tumor infiltration.Materials and Methods: We retrospectively identified 15 pediatric and young adult patients (mean age: 16±4 years) with bone sarcomas who underwent 18 MRI scans at 1 h (n=7) or 24 h (n=11) after intravenous ferumoxytol infusion. Twelve patients also received a gadolinium-enhanced MRI. We determined tumor invasion into the joint or pleural space based on histology (n=11) and imaging findings (n=4). We compared the signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) of the joint or pleural fluid for tumors with and without invasion using a Mann-Whitney U test.Results: MRI scans 24 h after intravenous ferumoxytol infusion demonstrated a positive T1 enhancement of the effusion in all joints and pleural spaces with tumor infiltration and no joint or pleural space without infiltration. Corresponding SNR (P=0.004) and CNR (P=0.004) values were significantly higher for joints and pleural spaces with tumor infiltration than without. By contrast, unenhanced MRI, gadolinium-enhanced MRI and 1-h post-contrast ferumoxytol MRI did not show any enhancement of the joint or pleural effusion, with or without tumor infiltration.Conclusion: This pilot study suggests that 24-h post-contrast ferumoxytol MRI scans can noninvasively differentiate between joints with and without tumor infiltration. [ABSTRACT FROM AUTHOR]

There has been an increase in the use of acetylsalicylic acid (ASA, Aspirin®) among patients with stroke and heart disease as well as in aging populations as a means of primary prevention. The potentially life-threatening consequences of a postoperative hemorrhagic complication after neurosurgical operative procedures are well known. In the present study, we evaluate the risk of continued ASA use as it relates to postoperative hemorrhage and cardiopulmonary complications in patients undergoing cerebral aneurysm surgery. We retrospectively analyzed 200 consecutive clipping procedures performed between 2008 and 2018. Two different statistical models were applied. The first model consisted of two groups: (1) group with No ASA impact - patients who either did not use ASA at all as well as those who had stopped their use of the ASA medication in time (> = 7 days prior to operation); (2) group with ASA impact - all patients whose ASA use was not stopped in time. The second model consisted of three groups: (1) No ASA use; (2) Stopped ASA use (> = 7 days prior to operation); (3) Continued ASA use (did not stop or did not stop in time, <7 days prior to operation). Data collection included demographic information, surgical parameters, aneurysm characteristics, and all hemorrhagic/thromboembolic complications. A postoperative hemorrhage was defined as relevant if a consecutive operation for hematoma removal was necessary. An ASA effect has been assumed in 32 out of 200 performed operations. A postoperative hemorrhage occurred in one out these 32 patients (3.1%). A postoperative hemorrhage in patients without ASA impact was detected and treated in 5 out of 168 patients (3.0%). The difference was statistically not significant in either model (ASA impact group vs. No ASA impact group: OR = 1.0516 [0.1187; 9.3132], p = 1.000; RR = 1.0015 [0.9360; 1.0716]). Cardiopulmonary complications were significantly more frequent in the group with ASA impact than in the group without ASA impact (p = 0.030). In this study continued ASA use was not associated with an increased risk of a postoperative hemorrhage. However, cardiopulmonary complications were significantly more frequent in the ASA impact group than in the No ASA impact group. Thus, ASA might relatively safely be continued in patients with increased cardiovascular risk and cases of emergency cerebrovascular surgery. [ABSTRACT FROM AUTHOR]

This paper summarizes the 2020 Diversity in Radiology and Molecular Imaging: What We Need to Know Conference, a three-day virtual conference held September 9–11, 2020. The World Molecular Imaging Society (WMIS) and Stanford University jointly organized this event to provide a forum for WMIS members and affiliates worldwide to openly discuss issues pertaining to diversity in science, technology, engineering, and mathematics (STEM). The participants discussed three main conference themes, "racial diversity in STEM," "women in STEM," and "global health," which were discussed through seven plenary lectures, twelve scientific presentations, and nine roundtable discussions, respectively. Breakout sessions were designed to flip the classroom and seek input from attendees on important topics such as increasing the representation of underrepresented minority (URM) members and women in STEM, generating pipeline programs in the fields of molecular imaging, supporting existing URM and women members in their career pursuits, developing mechanisms to effectively address microaggressions, providing leadership opportunities for URM and women STEM members, improving global health research, and developing strategies to advance culturally competent healthcare. [ABSTRACT FROM AUTHOR]

Objectives: To determine the performances of clinical examination, ultrasonography, and MRI for diagnosing non-displaced and displaced ulnar collateral ligament (UCL) tears. Methods: Based on a literature search of Medline, ISI Web of Science, Embase, and Scopus between January 1990 and December 2019, all published original articles which met the inclusion criteria were included. We determined the pooled sensitivities, specificities, and accuracies of clinical examination, ultrasonography, and MRI using a meta-analysis based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses–Diagnostic Test Accuracy (PRISMA-DTA) guidelines. Results: A total of 17 studies with 519 subjects reporting diagnostic performances of clinical examination (8), ultrasonography (12), and MRI (5) met the inclusion criteria. For ruling out UCL tears, the pooled sensitivities were similarly high for clinical examination (97% (95% confidence interval [CI], 93–99%)), ultrasonography (96% (95% CI, 94–98%)), and MRI (99% (95% CI, 92–100%)) (p = 0.3). For ruling in UCL tears, the pooled specificities were higher for MRI (100% (95% CI, 87–100%)) when compared to ultrasonography (91% (95% CI, 86–95%)) (p = 0.1) and clinical examination (85% (95% CI, 78–91%)) (p = 0.04). For the diagnosis of displaced UCL tears, MRI had a higher specificity (92% (95% CI, 73–99%)) than ultrasonography (72% (95% CI, 63–80%)) (p = 0.2). Conclusions: Clinical examination, ultrasonography, and MRI have similarly high sensitivities for ruling out UCL tears in patients presenting with a thumb injury. MRI and ultrasonography have high specificities to confirm the presence of suspected UCL tears. MRI performs best for differentiating non-displaced from displaced UCL tears. Key Points: • Clinical examination followed by ultrasonography is the most appropriate test for ruling out ulnar collateral ligament (UCL) tears of the thumb. • MRI and ultrasonography both have high specificities to confirm the presence of a suspected UCL tear. • MRI outperforms ultrasonography for differentiating non-displaced from displaced UCL tears. [ABSTRACT FROM AUTHOR]

Objective: To describe and illustrate the magnetic resonance imaging (MRI) anatomy of the anterior femoral cutaneous nerve (AFCN) and a new technique for cryoanalgesia of the AFCN for long-term analgesic treatment of recalcitrant AFCN-mediated neuropathic pain.Materials and Methods: Using a procedural high-resolution MRI technique, we describe the MRI anatomy of the AFCN. Three patients (mean age, 48 years; range, 41-67 years) with selective nerve block-verified recalcitrant AFCN-mediated anterior thigh pain were enrolled to undergo cryoanalgesia of the AFCN. Procedures were performed under MRI guidance using clinical wide-bore MR imaging systems and commercially available cryoablation system with MR-conditional probes. Outcome variables included technical success, clinical effectiveness including symptom relief measured on an 11-point visual analog scale, frequency of complications, and procedure time.Results: Procedural MRI allowed to successfully demonstrate the course of the AFCN, accurate cryoprobe placement, and monitoring of the ice ball, which resulted in technically successful iceball growth around the AFCN in all cases. All procedures were clinically effective, with median pain intensity decreasing from 8 (7-9) before the procedure to 1 (0-2) after the procedure. The cryoanalgesia effect persisted during a 12-month follow-up period in all three patients. No major complications occurred. The average total procedure time was 98 min (range, 85-125 min).Conclusion: We describe the MRI anatomy of the AFCN and a new technique for cryoanalgesia of the AFCN using MRI guidance, which permits identification of the AFCN, selective targeting, and iceball monitoring to achieve long-term AFCN-mediated neuropathic pain relief. [ABSTRACT FROM AUTHOR]

The aim of this work was to assess the influence of pH and temperature of bath plating on the performance of Ni-Cu/Cr2O3 nanocomposite coatings in a corrosive environment. For this purpose, Ni-Cu/Cr2O3 nanocomposite coatings were successfully carried out on the carbon steel by co-electrodeposition method from an aqueous composing of H2O, NiSO4, NiCl, CuSO4, Na3C6H5O7, and H3BO3 with and without 6 g/L Cr2O3 nanoparticles. The microstructure of samples was studied by x-ray diffraction and scanning electron microscopy, and corrosion behavior of the coatings was assessed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in the 3.5% NaCl solution. It was observed that by increasing the bath pH from 3 to 7 the corrosion current density (icorr) determined by Tafel extrapolation method was changed from 7.4 to 12.5 µA/cm2 and that polarization resistance (RP) obtained from EIS measurements was decreased from 850 to 452 Ω·cm2. The values of icorr and RP were changed from 11.2 µA/cm2 and 514 Ω·cm2 to 6.1 µA/cm2 and 1265 Ω·cm2, respectively, as the bath temperature was varied from 25 to 45 °C. Compared to the Ni-Cu nanocrystalline coating, the value of Rp showed more than 324% improvement when co-electrodeposition of Ni, Cu, and Cr2O3 was carried out at a temperature of 45 °C and pH value of 4.5. [ABSTRACT FROM AUTHOR]

In this paper, a predictive controller approach is proposed for depth and steer control of an Autonomous Underwater Vehicle (AUV). The predictive controller is an advanced control technique that performs control in form of online at any sampling time. AUV control has a lot of complexity due to the coupled nonlinear dynamics, parametric uncertainty and external disturbances due to underwater conditions. In addition, the AUV in this paper has constraints on actuators, which make its control more complicated. One of the challenges against implementing of predictive controller is their computational burden and the time consuming control operations at each time step. In this research, the Laguerre orthogonal functions are used for the predictive controller design to optimize and educe computational burden in time interval. The designed controller has several advantages such as being online and optimized, high accuracy, implementation capability, interaction with the constraints and robustness to disturbances. In order to demonstrate the efficiency of the method, the proposed controller is simulated for the AUV and the calculation time of the controllers with and without the Laguerre functions is compared with each other. Using Laguerre functions, the simulation results and their implementation on the board show the favorable efficiency and effectiveness of the proposed controller. Additionally, we have compared the proposed method with the LQR method. The obtained results confirm the superiority of various predictive controller methods. [ABSTRACT FROM AUTHOR]

Nanostructures of titanium dioxide, polyaniline, halloysite, and carbon nanotubes have an excellent effect to improve environmental protection and surface properties of coatings like anticorrosion and self-cleaning attributes. In this research, we studied the individual effect of adding each nanostructure within the polyurethane matrix and also all nanostructure combinations with each other on the mentioned properties. To reach this aim, the polyurethane nanocomposites were prepared; then, anticorrosion and self-cleaning tests were carried out on the samples. FTIR spectroscopy and FESEM images were used to characterize the nanocomposite additives and coating influence. According to the obtained results, the polyurethane coating modified with titanium dioxide/polyaniline/halloysite nanotube/carbon nanotube nanocomposite showed very higher corrosion potential and resistance and lower corrosion current in the comparison with other coatings. Also, the mentioned polyurethane nanocomposite coating showed good hydrophilicity and it decolorized a dye contaminant with high efficiency which makes them appropriate candidate for the protection of the substrate against environmental destructive factors. [ABSTRACT FROM AUTHOR]

Abstract: Sulfur compounds are one of the major problems and undesirable contaminants in the oil and gas industries. To address this issue, mercaptan removal from the gas stream in a fixed bed reactor under nanocatalyst was investigated. In this work, meso-tetrakis (4-carboxyphenyl) porphyrinatoiron (III) chloride-supported graphene oxide [GO-FeTCPP (Cl)] nanocatalyst was synthesized and adsorption of mercaptan on nanocatalyst was studied. Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), BET, and Raman spectroscopy analysis were used to characterize the nanocatalyst. This experiment investigated how temperature and Gas Hour Space Velocity (GHSV) parameters affect the mercaptan removal in presence of nanocatalyst. The research results confirmed that the reaction rate improves with increasing temperature and decreasing GHSV. According to the results, at 100 °C and GHSV of 1000 h−1, the maximum conversion (~ 96%) of reaction was reached.Graphical abstract: [ABSTRACT FROM AUTHOR]

Today, the exploration about synthesis of nanoparticles is much of interest to materials scientists. In this work, copper nanoparticles have been successfully synthesized by immersion deposit method in the absence of any stabilizing and reducing agents. Copper (II) sulfate pentahydrate as precursor salt and distilled water and Ethylene glycol as solvents were used. The copper nanoparticles were deposited on plates of low carbon steel. The effects of copper sulfate concentrations and solvent type were investigated. X-ray diffraction, scanning electron microscopy and UV-Visible spectroscopy were taken to investigate the crystallite size, crystal structure, and morphology and size distribution and the growth process of the nanoparticles of obtained Cu particles. The results indicated that the immersion deposit method is a particularly suitable method for synthesis of semispherical copper nanoparticles with the crystallites size in the range of ~22 to 37 nm. By increasing the molar concentration of copper sulfate in distilled water solvent from 0.04 to 0.2 M, the average particles size is increased from 57 to 81 nm. The better size distribution of Cu nanoparticles was achieved using a lower concentration of copper sulfate. By increasing the molar concentration of copper sulfate in water solvent from 0.04 to 0.2, the location of the SPR peak has shifted from 600 to 630 nm. The finer Cu nanoparticles were formed using ethylene glycol instead water as a solvent. Also, the agglomeration and overlapping of nanoparticles in ethylene glycol were less than that of water solvent. [ABSTRACT FROM AUTHOR]

Nowadays access control has an important role in management of access to system resources. Almost all of the current attribute based access control (ABAC) models do not meet all the operational needs in access decision while it absolutely will be an important role in the future access control models. We believe that meeting the operational need in missions is necessary in ranking the attributes which are existed in the access control policies. In this paper we propose a new approach that helps to enhance ABAC. It creates the quantitative capability which we named it quantitative ABAC and is based on decision fusion. We determine the attributes which have the most important role in the enterprises access management. Then, the experts consider and prioritize the attributes to determine which of attributes are more important than others. In the other word, we provide the weights as the importance of access control attributes based on decision-makers' viewpoints by utilizing ordered weighted averaging for the proposed prioritization. As the result of this research, it is possible that if there are some corrected values with high ranking among N parameters in attributes, the permission may be granted. The case study considerations show that decision fusion can be useful in solving some challenges of risk adaptable access control models. This enables policy-makers to manage and control the system resources more accurately and flexibility in integrated and complex systems. The results of this study could be useful in integrated environments such as c4i systems. [ABSTRACT FROM AUTHOR]

UiO-66 amine functionalized was synthesized by solvothermal method. Post-synthetic modification of UiO-66-NH with piperazine, a known promoter to enhance the chemisorption rate of CO uptake, was carried out and analyzed to understand its crystalline structure, morphology and porous structure. Results show that piperazine is an effective agent for enhancing the capacity of absorption of CO. This porous product exhibits an improved CO uptake at pressures up to 3000 kPa via physisorption and chemisorption mechanisms. The CH adsorption and desorption isotherms on UiO-66, UiO-66-NH and pip-UiO-66-NH at temperature of 298.15 K and pressures ranging from 0 to 5000 kPa were carried out. IAS theory for a mixture of 0.05 bar CO, 0.85 bar CH and 0.1 bar other gas revealed a selectivity factor of 19.09 for CO/CH from pip-UiO-66-NH. Results show that these materials are effective adsorbents for CO and CH uptakes. [ABSTRACT FROM AUTHOR]

Nanoporous activated carbons, as adsorbent for CO storage, were prepared from walnut shells via two chemical processes including phosphoric acid treatment and KOH activation at high temperature. Specific surface area and porosities were controlled by KOH concentration and activation temperature. The obtained adsorbents were characterized by N2 adsorption at 77.3 K. Their carbon dioxide adsorption capacities were measured at different pressures at 290 K by using volumetric adsorption equipment. The KOH-treated nanoporous carbons typically led to the production of high specific surface areas and high micropore volumes and showed better performance for CO adsorptions. The maximum experimental value for adsorption capacity happened when pressure increased from 5 to 10 bar (1.861-2.873mmol·g). It was found that in order to improve the highest capacity of CO adsorption for KOH-modified carbon (9.830-18.208mmol·g), a KOH: C weight ratio of 3.5 and activation temperature of 973 K were more suitable for pore development and micro-mesopore volume enhancement. [ABSTRACT FROM AUTHOR]

We describe a hybrid nanoadsorbent prepared by depositing graphene on the zeolite clinoptilolite by chemical vapor deposition. The resulting sorbent is well suited for the preconcentration of lead(II) and cadmium(II) by ultrasound-assisted dispersive micro solid-phase extraction. An extraction unit has been designed and manufactured that facilitates handling of small sample volumes. The effects of sample pH, amount of sorbent, concentration and volume of elution and time of ultrasonic bath were investigated. The nanoadsorbent was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray microanalysis, all of which revealed the high surface area of the graphene sheets on the clinoptilolite. The extraction recoveries when using the new nanoadsorbent are 97 % (as opposed to a mere 10 % in case of clinoptilolite only). It is assumed that the graphene sheets located around the porous structure of clinoptilolite are acting as a barrier against macromolecules potentially existing in the sample matrices. The method was applied to the determination of lead and cadmium in water and human serum samples by electrothermal atomic absorption spectrometry. The detection limits were as low as 70 and 4 ng L for Pb(II) and Cd(II), respectively. The accuracy of the method was underpinned by correct analysis of a standard reference material (SRM: 203105 Seronorm Trace Elements Serum L-2). Graphical Abstract: New nanoadsorbent, graphene/ clinoptilolite hybrid, was prepared which is suitable for separating and preconcentrating the metal ions from biological samples. In the propose method, the synthesized G/CL nanoadsorbent was used in ultrasound- assisted dispersive micro solid phase extraction method with applying the new designed extraction unit. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The influence of cobalt particle size on catalyst performance in Fischer-Tropsch synthesis (FTS) has been investigated using functionalized carbon nanotube (CNT)-supported nano catalyst. The catalysts were synthesized by wet impregnation and special sol-gel technique. The catalysts were characterized by BET, XRD, H chemisorption, TPR, and TEM. According to TEM analysis, small Co particles (3-8 nm) synthesized by sol-gel technique have very narrow particle size distributions and are mostly confined inside the CNT. The deposition of cobalt nanoparticles synthesized by sol-gel technique on the functionalized CNT shifted the reduction peaks to a low temperature, indicating higher reducibility for uniform cobalt particles. The proposed sol-gel technique increased the FTS rate from 0.62 to 0.71 g HC/gcat./h, C selectivity increased 7% and CH selectivity decreased 4%, compared to that prepared by incipient wetness impregnation. This new catalyst preparation method may offer an attractive alternative for nanoparticles synthesis with uniform, and various size distributions. [ABSTRACT FROM AUTHOR]