Te/CdTe and Al/CdTe Interfacial Energy Band Alignment by Atomistic Modeling.

A synergistic approach that incorporates first-principles atomistic modeling with numerical device simulations is used to systematically evaluate the role of heterointerfaces within metal-chalcogenide-based photovoltaic technologies. Two interfaces involving either a tellurium back contact or aluminum back electrode combined with a cadmium telluride absorber layer within cadmium-telluride-based thin-film solar cells are investigated on an atomic scale to determine the mechanisms contributing to variations in device performance. Electronic structures and predicted charge transport behavior with respect to cadmium and tellurium termination of the absorber layer are studied along the polar oriented CdTe{111} facets. The computational methodology reveals a noticeable contrast between the Schottky barrier forming Al/CdTe interface versus the Type I Te/CdTe heterojunction. Greater band bending features are exhibited by the cadmium termination as opposed to the tellurium termination for each interface case. Subsequent device modeling suggests that 3.6% higher photovoltaic conversion efficiency is achievable for the cadmium termination relative to the tellurium termination of the Te/CdTe interface. Based strictly on an idealistic representation, both interface models show the importance of atomic-scale interfacial properties for cadmium telluride solar cell device performance with their bulk properties being validated in comparison to published experimental data. The synergistic approach offers a suitable method to analyze solar cell interfaces through a predictive computational framework for the engineering and optimization of metal-chalcogenide-based thin-film photovoltaic technologies.

Understanding the Copassivation Effect of Cl and Se for CdTe Grain Boundaries.

Chlorine passivation treatment of cadmium telluride (CdTe) solar cells improves device performance by assisting electron-hole carrier separation at CdTe grain boundaries. Further improvement in device efficiency is observed after alloying the CdTe absorber layer with selenium. High-resolution secondary ion mass spectroscopy (NanoSIMS) imaging has been used to determine the distribution of selenium and chlorine at the CdTe grain boundaries in a selenium-graded CdTe device. Atomistic modeling based on density functional theory (DFT-1/2) further reveals that the presence of selenium and chlorine at an exemplar (110)/(100) CdTe grain boundary passivates critical acceptor defects and leads to n-type inversion at the grain boundary. The defect state analysis provides an explanation for the band-bending effects observed in the energy band alignment results, thereby elucidating mechanisms for high efficiencies observed in Se-alloyed and Cl-passivated CdTe solar cells.

Pediatric scaphoid fracture: diagnostic performance of various radiographic views.

PURPOSE: The purpose of this study was to systematically investigate the performance of different radiographic views in the identification of scaphoid fractures in children. METHODS AND MATERIALS: This case-control study compared 4-view radiographic examinations of the wrist between children with scaphoid fracture and age- and sex-matched children without fractures performed between January 2008 and July 2019. After randomization, each examination was reviewed 3 times, at least 1 week apart, first using each view separately and later using multiple views without (3-view) and with the posteroanterior (PA) scaphoid view (4-view), to determine the presence or absence of a scaphoid fracture. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated with inter-rater agreement. RESULTS: The study group of 58 children (48 boys and 10 girls; mean age 13.1 ± 2.1 years) included 29 with scaphoid fractures (8 corner, 9 distal pole, 10 waist, and 2 proximal pole) and 29 without fractures. Multiple views had higher sensitivity (3-view, 93.0%; 4-view, 96.5%) for fracture identification when compared to individual views (41.0-89.6%). The oblique view was 100% specific for the identification of a scaphoid fracture, but it lacked sensitivity. The PA scaphoid view had the highest sensitivity (89.6%) and NPV (90%) when compared to other individual views and its inclusion in the 4-view examinations produced the highest inter-rater agreement (93%, κ = 0.86). CONCLUSION: Multiple radiographic views of the wrist with the inclusion of a PA scaphoid view (4-view) produced the highest sensitivity, NPV, and inter-rater agreement for the identification of a scaphoid fracture in children.

Hand Bone Age Radiography: Comparison Between Slot-scanning and Conventional Techniques.

BACKGROUND: Determination and longitudinal monitoring of progressive skeletal maturity are essential in the management of children with scoliosis. Although different methods for determining skeletal maturity exists, the most widely practiced method relies on the ossification pattern of the bones of the hand and wrist, which is traditionally acquired using conventional techniques and after the acquisition of the spine using the low-dose slot-scanning technique. Whereas the existing published literature has published promising results on the use of the slot-scanning technique to acquire these hand and wrist radiographs, image quality and radiation dose have not been systematically compared between these techniques. Thus, the objective of our study is to compare image quality, interpretation reliability, and radiation dose of hand bone age radiographs between slot-scanning and conventional techniques using age- and sex-matched children. METHODS: This retrospective study included children who underwent hand radiographs using slot-scanning between October 1, 2019 and December 31, 2019; and matched children who underwent conventional radiography. Blinded to technique, 5 readers reviewed all radiographs after randomization to rate image quality and to determine bone age using the Greulich and Pyle classification. Dose area product was recorded. Mann-Whitney and t tests were used to compare variables between techniques and intraclass correlation (ICC) to determine observer agreement. RESULTS: Our study cohort of 194 children (128 girls, 66 boys; mean age: 13.7±2.3 y) included 97 slot-scanning and 97 conventional radiographs. One (1%) slot-scanning and no conventional radiograph was rated poor in image quality. There was almost perfect interpretation reliability with slot-scanning with high interobserver (ICC=0.948) and intraobserver (ICC=0.996) agreements, comparable with conventional radiographs (ICCs=0.919 and 0.996, respectively). Dose area product (n=158) was lower (P<0.002) with slot-scanning than with conventional techniques. CONCLUSION: Almost perfect interobserver reliability and intraobserver reproducibility with slot-scanning radiographs (performed using significantly lower radiation doses) suggest that this technique for hand bone age determination can be a reliable adjunct to scoliosis monitoring. LEVEL OF EVIDENCE: Level III.

Genetic cause for congenital methemoglobinemia in an Australian Pomeranian dog.

Little is known about genetic causes of congenital methemoglobinemia in dogs. Here, we report a CYB5 R3 mutation in a Pomeranian dog with congenital methemoglobinemia. A 6-year-old neutered female Pomeranian dog was investigated for cyanosis noticed during anesthesia for an orthopedic procedure. The history included lifelong mild exercise intolerance and bluish tongue. Methemoglobinemia was diagnosed using co-oximetry. The CYB5 R3 gene was analyzed by comparing the patient's genomic DNA with the reference canine sequence. Mutation functional significance was investigated using snpEff and multispecies protein homology analyses. A homozygous missense single nucleotide CYB5 R3 mutation (ATC ➔ CTC at codon 194) caused a p.Ile194Leu substitution. The pIle194 residue is highly conserved in other mammals, supporting the likely pathogenicity of the substitution. The mutation described here is identical to that associated with familial methemoglobinemia in a family of Japanese Pomeranian dogs. This observation, together with the homozygous mutation found in our case, indicates that the mutant allele may be widespread within the Pomeranian breed internationally.

Physiological, biochemical and histopathological changes associated with heatstroke in the galah (Eolophus roseicapilla) and rock dove (Columba livia).

The pathophysiology of heat illnesses in birds has not been well characterized. In this study, we describe the changes in heart rate, respiratory rate, blood biochemistry and histopathological findings in galahs and rock doves after heat exposure under standardized conditions designed to induce heatstroke. Birds in the heat-exposed group were exposed to environmental heat stress and compared to control birds. Both groups of birds were under general anaesthesia throughout the experiment and serial blood collections were performed for biochemical analyses, while organs were collected at the end of the experiment for histopathology. No electromyography traces consistent with the onset of heat cramps were observed in any of the birds. Biochemical changes suggestive of skeletal muscle and hepatocellular injury, including hyperkalaemia and increased serum muscle and hepatic enzyme activities, were often observed in heat-exposed galahs and rock doves at the onset of heatstroke. Microscopic analyses did not reveal any significant cardiac changes, although some lungs had signs of acute congestion. Some heat-exposed rock doves had microscopic changes indicative of necrosis in the pectoral muscle. There were significant hepatic changes in some heat-exposed galahs, but not in rock doves. This suggests that there may be species differences amongst birds in the organs most affected by heatstroke. The observed species differences in the physiological, biochemical and histopathological changes indicate that bird species should be studied separately for clinical syndromes such as heatstroke. RESEARCH HIGHLIGHTS Biochemical changes suggestive of skeletal muscle and hepatocellular injury in heat-exposed galahs and rock doves at the onset of heatstroke No electromyography traces consistent with the onset of heat cramps were observed Some heat-exposed rock doves had indications of necrosis in the pectoral muscle There were significant hepatic changes in some heat-exposed galahs.

General anesthesia with an injectable 8% v/v sevoflurane lipid emulsion administered intravenously to dogs.

OBJECTIVE: To evaluate the potential of an intravenous (IV) sevoflurane formulation for maintenance of general anesthesia in dogs. STUDY DESIGN: Prospective crossover design. ANIMALS: Six healthy, mature, mixed-breed dogs, four males and two females, weighing 11.7 ± 3.4 kg. METHODS: Anesthesia was induced and maintained with propofol IV for instrumentation. Baseline measurements were recorded before administration of either sevoflurane in oxygen (Sevo-Inh) or lipid-emulsified sevoflurane 8% v/v in 30% Intralipid IV (Sevo-E), 0.5 mL kg(-1) over 5 minutes followed by an infusion at 0.1-0.3 mL kg(-1)  minute(-1) . Dogs were breathing spontaneously. The 'up-and-down' technique was used to determine the minimum alveolar concentration (MAC) of sevoflurane. Over 120 minutes, a tail clamp was applied every 15 minutes and sevoflurane administration was adjusted depending on the response. End-tidal sevoflurane concentration and variables were recorded at 30, 60, 90, and 120 minutes: heart rate (HR), systemic arterial pressure (sAP), respiratory rate (fR ), end-tidal carbon dioxide tension, hemoglobin oxygen saturation (SaO2 ), arterial pH and blood gases, blood urea nitrogen, alanine aminotransferase, creatine kinase, gamma-glutamyl transferase, and aspartate aminotransferase. RESULTS: There were no significant differences between treatments for HR, sAP, fR , SaO2 , and biochemical variables (p > 0.05). pH and HCO3-were significantly decreased, and PaCO2 increased from baseline in Sevo-E (p < 0.05). MAC was significantly lower for Sevo-E than for Sevo-Inh, although the required dose of sevoflurane (g hour(-1) ) to maintain general anesthesia was not significantly different between treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of 8% v/v sevoflurane lipid emulsion IV was effective in maintaining general anesthesia in dogs, but resulted in moderate cardiopulmonary depression, metabolic and respiratory acidosis. The amount of sevoflurane (g hour(-1) ) required to maintain general anesthesia was significantly lower for inhaled than for IV sevoflurane.

Inferior pancreaticoduodenal artery aneurysms associated with occlusive lesions of the celiac axis: diagnosis, treatment options, outcomes, and review of the literature.

PURPOSE: To describe the presentation, treatment, and outcomes for 14 patients with aneurysms of the inferior pancreaticoduodenal arteries associated with occlusive lesions of the celiac axis, and to review the literature for similar cases. METHODS: Over a period of 12 years, 14 patients (10 women and 4 men) ranging in age from 26 to 50 (mean 46) years were demonstrated to have aneurysms of the inferior pancreaticoduodenal artery origin associated with stenosis or occlusion of the celiac axis. All patients were treated by a combination of surgery and interventional radiology. RESULTS: Outcome data collected between 3 months and 4 years (mean 2 years) demonstrated that all aneurysms remained excluded, and all 14 patients were well. The 49 case reports in the literature confirm the findings of this cohort. CONCLUSION: In inferior pancreaticoduodenal artery aneurysm resulting from celiac occlusive disease, endovascular treatment is best achieved by stenting the celiac axis and/or embolizing the aneurysm when necessary.

Litter size predicts adult stereotypic behavior in female laboratory mice.

Stereotypic behaviors are repetitive invariant behaviors that are common in many captive species and potentially indicate compromised welfare and suitability as research subjects. Adult laboratory mice commonly perform stereotypic bar-gnawing, route-tracing, and back-flipping, although great individual variation in frequency occurs. Early life factors (for example, level of maternal care received) have lasting effects on CNS functioning and abilities to cope with stress and therefore may also affect stereotypic behavior in offspring. Access to maternal resources and care are influenced by the number of pups in a litter; therefore, we examined both litter size and its potential correlate, weight at weaning, as early environmental predictors of adult stereotypic behavior in laboratory mice. Further, we assessed the effects on offspring stereotypic behavior of delaying the separation of mother and pups (weaning) beyond the standard 21 d of age. Analyzing stereotypic behavior in 3 different mouse colonies composed of 2 inbred strains (C57BL/6N and C57BL/6J) and an outbred stock (CD1[ICR]) revealed significant positive correlation between litter size and stereotypic behavior in female, but not male, mice. Weight and age at weaning did not significantly affect levels of stereotypy in either sex. Litter size therefore may be a useful indicator of individual predisposition to stereotypic behavior in female laboratory mice.

Strain-specific hyperkyphosis and megaesophagus in Add1 null mice.

The three adducin proteins (α, ß, and γ) share extensive sequence, structural, and functional homology. Heterodimers of α- and ß-adducin are vital components of the red cell membrane skeleton, which is required to maintain red cell elasticity and structural integrity. In addition to anemia, targeted deletion of the α-adducin gene (Add1) reveals unexpected, strain-dependent non-erythroid phenotypes. On an inbred 129 genetic background, Add1 null mice show abnormal inward curvature of the cervicothoracic spine with complete penetrance. More surprisingly, a subset of 129-Add1 null mice develop severe megaesophagus, while examination of peripheral nerves reveals a reduced number of axons in 129-Add1 null mice at four months of age. These unforeseen phenotypes, described here, reveal new functions for adducin and provide new models of mammalian disease.

Prescription sleep medicine for aircrew.

It is suggested that the Aerospace Medical Association convene an international expert body to determine the relevance of the pharmacological profiles of hypnotics to the practice of aviation medicine.

Hemorrhagic complications after Whipple surgery: imaging and radiologic intervention.

OBJECTIVE: The aim of this pictorial essay is to illustrate the radiologic patterns, sites of bleeding, and vascular interventional techniques used in the management of postpancreatectomy hemorrhage. CONCLUSION: Hemorrhagic complications occur in fewer than 10% of patients after Whipple pancreatoduodenectomy but account for as many as 38% of deaths. Bleeding typically occurs from the stump of the gastroduodenal artery, but other sites of bleeding are increasingly recognized.

Anti-CD4-targeted gold nanoparticles induce specific contrast enhancement of peripheral lymph nodes in X-ray computed tomography of live mice.

Antibody-conjugated gold nanoparticles have been applied as a biologically targeted contrast agent in live mice for one of the most widely used medical imaging methods, X-ray computed tomography. Such nanoprobes directed toward the CD4 receptor lead to distinctly enhanced X-ray contrast of peripheral lymph nodes. This study demonstrates the general feasibility of biologically specific X-ray imaging in living animals and discusses basic requirements for the use of nanoparticles as a targeted X-ray contrast agent.

Diet-induced obesity in two C57BL/6 substrains with intact or mutant nicotinamide nucleotide transhydrogenase (Nnt) gene.

The C57BL/6J (B6/J) male mouse represents a standard for diet-induced obesity (DIO) and is unique in expressing a loss-of-function nicotinamide nucleotide transhydrogenase (Nnt) gene. This mutation was associated with a marked reduction in glucose-stimulated insulin secretion from B6/J islets in vitro and moderately impaired glucose clearance in vivo. To assess the contribution of this Nnt mutation, we compared DIO responsiveness of Nnt-mutant B6/J males to Nnt wild-type C57BL/6NJ (B6/NJ) males over a 14-week period of feeding a high-fat (60% of calories) diet. Initial mean body weights at 6 weeks did not distinguish the substrains and both substrains were DIO-sensitive. However, B6/J males outgained the B6/NJ males, with a significant 3 g higher mean body weight at 20 weeks accompanied by significant increases in both lean and fat mass. Mean nonfasting serum glucose over time was also significantly higher in B6/J males, as was impairment of glucose tolerance assessed at 8 and 20 weeks of age. Serum leptin, but not insulin, was significantly higher in B6/J males over time. Potential contributions of the wild-type Nnt gene were demonstrable on a lower fat diet (10% of calories) where a significantly greater weight gain over time by B6/NJ males was correlated with a significantly higher serum insulin. In conclusion, DIO developed in response to 60% fat feeding regardless of Nnt allele status. Contribution of the B6/J-unique Nnt mutation was most evident in response to 10% fat feeding that resulted in reduced serum insulin and weight gain compared to B6/NJ males.

The response of C57BL/6J and BALB/cJ mice to increased housing density.

Increased numbers of mice housed per cage (that is, increased housing density) is seen as 1 way to reduce the costs of conducting biomedical research. Current empirically derived guidelines are based on the area provided per mouse depending on body weight as documented in the Guide for the Care and Use of Laboratory Animals. The current study aimed to provide a more scientific basis for housing density by examining the response of C57BL/6J and BALB/cJ mice to increased housing density from weaning to 5 mo of age, to determine those parameters most useful for future larger-scale studies. A wide range of phenotypic characteristics--including growth rate, body composition, hematology, serum biochemistry, hormone and metabolite measurements, in-cage telemetry, behavior, and cage microenvironment--was examined at various time points. The parameters showing greatest changes were: growth rate, which was significantly reduced in animals at the highest density; adrenal gland size, the proportion of adrenal cortex, and concentration of fecal corticosterone metabolites, all of which were increased at higher densities; and anxiety and barbering, which were more pronounced at higher densities. Cage microenvironment deteriorated with increasing density, but the increases in measured parameters were small, and their biologic impact, if any, was not apparent. The current findings indicate that mouse housing density can be increased 50% to 100% above the current recommendations (as floor area per mouse) with no or few apparent affects on mouse overall wellbeing. However, weight gain, fecal corticosterone metabolite levels, and barbering differed significantly with housing density and therefore are suggested as good measures of the response to alterations in housing.

Revascularization versus medical therapy for renal-artery stenosis.

BACKGROUND: Percutaneous revascularization of the renal arteries improves patency in atherosclerotic renovascular disease, yet evidence of a clinical benefit is limited. METHODS: In a randomized, unblinded trial, we assigned 806 patients with atherosclerotic renovascular disease either to undergo revascularization in addition to receiving medical therapy or to receive medical therapy alone. The primary outcome was renal function, as measured by the reciprocal of the serum creatinine level (a measure that has a linear relationship with creatinine clearance). Secondary outcomes were blood pressure, the time to renal and major cardiovascular events, and mortality. The median follow-up was 34 months. RESULTS: During a 5-year period, the rate of progression of renal impairment (as shown by the slope of the reciprocal of the serum creatinine level) was -0.07x10(-3) liters per micromole per year in the revascularization group, as compared with -0.13x10(-3) liters per micromole per year in the medical-therapy group, a difference favoring revascularization of 0.06x10(-3) liters per micromole per year (95% confidence interval [CI], -0.002 to 0.13; P=0.06). Over the same time, the mean serum creatinine level was 1.6 micromol per liter (95% CI, -8.4 to 5.2 [0.02 mg per deciliter; 95% CI, -0.10 to 0.06]) lower in the revascularization group than in the medical-therapy group. There was no significant between-group difference in systolic blood pressure; the decrease in diastolic blood pressure was smaller in the revascularization group than in the medical-therapy group. The two study groups had similar rates of renal events (hazard ratio in the revascularization group, 0.97; 95% CI, 0.67 to 1.40; P=0.88), major cardiovascular events (hazard ratio, 0.94; 95% CI, 0.75 to 1.19; P=0.61), and death (hazard ratio, 0.90; 95% CI, 0.69 to 1.18; P=0.46). Serious complications associated with revascularization occurred in 23 patients, including 2 deaths and 3 amputations of toes or limbs. CONCLUSIONS: We found substantial risks but no evidence of a worthwhile clinical benefit from revascularization in patients with atherosclerotic renovascular disease. (Current Controlled Trials number, ISRCTN59586944.)