Reverse bias voltage testing of 8 cm x 8cm silicon solar cells

A study is described of the reverse I-V characteristics of the largest space qualified silicon solar cells currently available (8 x 8 cm) and of reverse bias voltage (RBV) testing performed on these cells. This study includes production grade cells, both with and without cover glass. These cells span the typical output range seen in production. Initial characteristics of these cells are measured at both 28 and 60 C. These measurements show weak correlation between cell output and reverse characteristics. Analysis is presented to determine the proper conditions for RBV stress to simulate shadowing effects on a particular array design. After performing the RBV stress the characteristics of the stressed cells are remeasured. The degradation in cell performance is highly variable which exacerbates cell mismatching over time. The effect of this degradation on array lifetime is also discussed. Generalization of these results to other array configurations is also presented

Identification of temperature profile and heat transfer on a dielectric membrane for gas sensors by `COSMOS' program simulation

The application of commercial 3-D software `COSMOS' for the design and thermal analysis of the low power consumption test structures with dielectric membrane for gas microsensors is presented. Within this work, the simulation provides the estimation of the temperature profile on the active area and the whole membrane including the four bridges and the heating efficiency in the temperature range 20-500 °C. Unravelling of the heat loss mechanisms in terms of radiation, convection, conduction by air and solid materials during heat transfer on the dielectric membrane is reported for the first time as a mean to evaluate by 3-D simulation the contribution of technological processes and lay-out design to the total heat losses

Liver procurement as part of multiple organ procurement

Departamentul de Chirurgie Generală şi Transplant Hepatic “Dan Setlacec”, Institutul Clinic Fundeni, Bucureşti, România, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Scop: Prelevarea hepatică, etapă premergătoare transplantului hepatic, parte din prelevarea multiorgan, contribuie prin acuratețea și corectitudinea intervenției la obținerea unei grefe hepatice de bună calitate cu rezultate bune ale transplantului atît imediate cât și pe termen lung. Lucrarea de față își propune să evidențieze importantul rol al identificării variantelor anatomice și adaptarea metodelor de prelevare în funcție de acestea.Material şi metode: Pe parcursul perioadei 1 ianuarie 2000-16 iunie 2015 s-au efectuat în Centrul nostru 666 prelevări multiorgan. O importanță deosebită a fost acordată recunoașterii variantelor anatomice arteriale, acestea adaugând un grad de dificultate procedurii, dar fiind totodată esențiale pentru asigurarea succesului intervenției. Rezultate: Caracteristicile heterogene ale donatorilor au obligat la aplicarea unei game variate de tehnici de prelevare, adaptate fiecărei situații, așa cum au fost descrise în lucrarea de față, un pas cheie pentru obținerea unei grefe viabile pentru transplant. Concluzii: Multiplele tehnici de prelevare hepatică pot fi aplicate cu succes când sunt adaptate fiecarui donator, scurtând timpul de prelevare și furnizând o grefă de cea mai bună calitate.Purpose: Liver procurement, the preliminary stage of liver transplantation, is a part of multi-organ procurement, and it contributes, with its accuracy and correctness to the high quality liver graft, with the best results in the transplantation process (both immediate and long term). This paper is framed to enlighten the important role of identification of anatomical variants and the selection of the procurement technique that suits most. Material and methods: During 1st Jan 2000-16th Jun 2015 a number of 666 multi-organ procurements were performed in our center. A special attention was paid in recognizing of anatomical variants of blood vessels (especially arterial blood vessels), which added a high degree of difficulty to the procedures, but was considered to be vital in order to ensure the success of the intervention. Results: Heterogeneous characteristics of donors imposed the implementation of a variety of sampling techniques, adapted on each situation as was described in the paper, an essential step to obtain a viable liver / organ graft suitable for the transplant. Conclusions: The multiple methods of liver procurement can be successfully applied when it is adapted to each of the donors, thus shortening the actual time of the liver harvesting, delivering the best quality of the new liver graft

A comparison of vitamin D and cathelicidin (LL-37) levels between patients with active TB and their healthy contacts in a high HIV prevalence setting: a prospective descriptive study

BACKGROUND: Studies from Asia and Europe indicate an association between vitamin D deficiency and susceptibility to TB. We performed an observational case-control study to determine vitamin D and cathelicidin (LL-37) levels and their association with active TB in newly diagnosed and microbiologically confirmed adult TB patients in Zambia, a high HIV prevalence setting. METHODS: Both total vitamin D and LL-37 were measured using ELISA from serum and supernatant isolated from cultured whole blood that was stimulated with heat-killed Mycobacterium tuberculosis. Statistical analysis was performed using STATA statistical software version 12. RESULTS: The median vitamin D in TB patients and healthy contacts was 28.7 (19.88-38.64) and 40.8 (31.2-49.44) ng/ml, respectively (p<0.001). The median LL-37 in TB patients compared with healthy contacts was 1.87 (2.74-8.93) and 6.73 (5.6-9.58) ng/ml, respectively (p=0.0149). Vitamin D correlation with LL-37 in healthy contacts was R2=0.7 (95% CI 0.566 to 0.944), p<0.0001. Normal vitamin D significantly predicted a healthy status (OR 4.06, p=0.002). CONCLUSIONS: Significantly lower levels of vitamin D and LL-37 are seen in adults with newly diagnosed active TB. Longitudinal studies across various geographical regions are required to accurately define the roles of vitamin D and LL-37 in preventive and TB treatment outcomes

The Role of Recipient Characteristics in Health Video Communication Outcomes: Scoping Review

Background: The importance of effective communication during public health emergencies has been highlighted by the World Health Organization, and it has published guidelines for effective communication in such situations. With video being a popular medium, video communication has been a growing area of study over the past decades and is increasingly used across different sectors and disciplines, including health. Health-related video communication gained momentum during the SARS-CoV-2 pandemic, and video was among the most frequently used modes of communication worldwide. However, although much research has been done regarding different characteristics of video content (the message) and its delivery (the messenger), there is a lack of knowledge about the role played by the characteristics of the recipients for the creation of effective communication. Objective: The aim of this review is to identify how health video communication outcomes are shaped by recipient characteristics, as such characteristics might affect the effectiveness of communication. The main research question of the study is as follows: do the characteristics of the recipients of health videos affect the outcomes of the communication? Methods: A scoping review describing the existing knowledge within the field was conducted. We searched for literature in 3 databases (PubMed, Scopus, and Embase) and defined eligibility criteria based on the relevance to the research question. Recipient characteristics and health video communication outcomes were identified and classified. Results: Of the 1040 documents initially identified, 128 (12.31%) met the criteria for full-text assessment, and 39 (3.75%) met the inclusion criteria. The included studies reported 56 recipient characteristics and 42 communication outcomes. The reported associations between characteristics and outcomes were identified, and the potential research opportunities were discussed. Contributions were made to theory development by amending the existing framework of the Integrated-Change model, which is an integrated model of motivational and behavioral change. Conclusions: Although several recipient characteristics and health video communication outcomes were identified, there is a lack of robust empirical evidence on the association between them. Further research is needed to understand how the preceding characteristics of the recipients might affect the various outcomes of health video communication

No multi-graviton theories in the presence of a Dirac field

The cross-couplings among several massless spin-two fields (described in the free limit by a sum of Pauli-Fierz actions) in the presence of a Dirac field are investigated in the framework of the deformation theory based on local BRST cohomology. Under the hypotheses of locality, smoothness of the interactions in the coupling constant, Poincare invariance, (background) Lorentz invariance and the preservation of the number of derivatives on each field, we prove that there are no consistent cross-interactions among different gravitons in the presence of a Dirac field. The basic features of the couplings between a single Pauli-Fierz field and a Dirac field are also emphasized.Comment: 48 page