The role of endoscopic ultrasonography in the differential diagnosis of biliary obstructions

Dispensarul Oncologic Regional, Secţia Endoscopie, St.Petersburg, Rusia, 2 IMSP SR ACSR, Secţia endoscopie şi chirurgie miniinvazivă Chişinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Tehnologiile moderne modifică tot mai semnificativ evaluarea diagnostică a pacienților cu obstrucțiile biliare. Aplicarea UltraSonografiei Endoscopice (USEnd) este una dintre metodele de ultimă oră în depistarea diferitor maladii, ce contribuie la obstrucţii biliare. Scopul: Cercetarea actuală a fost orientată spre aprecierea rolului USEnd în diagnosticarea patologiilor ce pot provoca dezvoltarea obstrucţiilor biliare. Rezultate: Au fost studiate fişele de examinare a 42 pacienţi evaluați prin USEnd din evidenţa Dispensarului Oncologic Regional din St.Petersburg. Concluzie: USEnd, este o metodă promiţătoare de diagnostic diferenţial în optimizarea algoritmului managementului obstrucţiilor biliare.Introduction: The emergent imaging technologies increasingly modify the diagnostic evaluation of the patients with biliary obstructions. One of the recently investigated improvements pertains to the use of Endoscopic Ultrasonography (USEnd) in the hepatobiliary imaging. Aim: This study is oriented towards the appreciation of the role of USEnd in the diagnosis of the pathologies pertaining to biliary obstruction. Results: The results obtained at the St.Petersburg Regional Oncologic Dispensary after the application of USEnd for 42 patients were analysed. Conclusion: The possibilities of USEnd in the differential diagnosis for patients with biliary obstructions may optimize the diagnosis and treatment algorithms

Temperature Dependence of the Exciton Gap in Monocrystalline CuGaS2

Single crystals of CuGaS2 have been grown by chemical vapour transport. Their near-band gap photoluminescence properties were investigated in the temperature range of 10-300 K. The variation of the exciton gap energy with temperature was studied by means of a three-parameter thermodynamic model, the Einstein model and the Pässler model. Values of the band gap at T=0 K, of a dimensionless constant related to the electron-phonon coupling, and of an effective and a cut-off phonon energy have been estimated. It has also been found that the major contribution of phonons to the shift of Eg as a function of T in CuGaS2 is mainly from optical phonons

Effect of Precursor Stacking Order and Sulfurization Temperature on Compositional Homogeneity of CZTS Thin Films

In this study, Cu2ZnSnS4 CZTS absorber layers were grown by sequential deposition of metallic Cu, Zn, and Sn layers by DC magnetron sputtering on Mo coated glass followed by annealing in sulfur atmosphere in a rapid thermal processing RTP system for 3 min at 500 C, 550 C and 600 C. Two different metal stacking sequences were investigated Mo Zn Sn Cu and Mo Cu Sn Zn Cu both with a Cu poor and Zn rich composition. For the Mo Cu Sn Zn Cu stack, the initial Mo Cu Sn layer was pre annealed to yield homogeneous Cu Sn alloys on which Zn and the final Cu was deposited afterwards. Compositional inhomogeneities were studied by measuring X ray fluorescence XRF before and after KCN etching of the sulfurized samples as well as by glow discharge optical emission spectroscopy GDOES . Additionally, crystallographic properties were analyzed by X ray diffraction XRD and Raman spectroscopy. For the Mo Zn Sn Cu precursor, we find that the initial stacking order is partially preserved with a Cu rich surface and a Zn rich bottom. In contrast, the modified stacking Mo Cu Sn Zn Cu leads to an improved compositional homogeneity. While a Zn rich composition is still found at the bottom part of the film, after sulfurization for 3 min at 600 C the surface and bulk part show homogeneous element distributions close to that of CZT

Polarized Raman scattering analysis of Cu2ZnSnSe4 and Cu2ZnGeSe4 single crystals

The polarized Raman spectra of the Cu2ZnSnSe4 and Cu2ZnGeSe4 single crystals were measured for various in plane rotation angles on the basal 1 1 2 crystal facet. The position of up to 15 for Cu2ZnSnSe4 and 16 for Cu2ZnGeSe4 Raman peaks was determined in the spectral region 50 300 cm 1. From the analysis of the experimental dependence of the inten sity of the Raman peaks with the rotation angle, a symmetry assignment for most of the de tected modes and an estimation of numerical values of Raman tensor elements were derived. The kesterite type structure of Cu2ZnSnSe4 and Cu2ZnGeSe4 single crystals was established by the quantity of the observed nonpolar A and polar B TO LO symmetry mode

Optoelectronic property comparison for isostructural Cu2BaGeSe4 and Cu2BaSnS4 solar absorbers

To target mitigation of anti site defect formation in Cu2ZnSnS4 amp; 8722;xSex, a new class of chalcogenides, for which Ba or Sr group 2 replace Zn group 12 , has recently been introduced for prospective solar absorber application. Cu2BaGeSe4 CBGSe and Cu2BaSnS4 CBTS are two such compounds, which share a common trigonal crystal structure P31 space group and similar quasi direct band gap amp; 8764;2 eV . While CBTS based films have already been studied, there are no reports yet on films and solar cells based on related CBGSe. To identify key differences and similarities in the electronic properties between these two materials, electronic characteristics e.g., carrier concentration, mobility, electron affinity, defect levels, recombination, and charge carrier kinetics of vacuum deposited CBGSe and CBTS films are compared using a variety of characterization methods. Hall effect measurements reveal that CBGSe films have relatively higher hole carrier concentration and lower mobility 3 1015 cm amp; 8722;3, 0.6 cm2 V amp; 8722;1 s amp; 8722;1 compared to CBTS 5 1012 cm amp; 8722;3, 3.5 cm2 V amp; 8722;1 s amp; 8722;1 . Photoelectron spectroscopy yields low electron affinity values for both CBGSe 3.7 eV and CBTS 3.3 eV , pointing to the necessity of pursuing low electron affinity buffer materials for both types of absorbers. At low temperatures, CBGSe films show free exciton photoluminescence, as well as pronounced deep level emission at amp; 8764;1.4 eV, while CBTS films exhibit a strong bound exciton signal with noticeably less intense deep level emission than for CBGSe. Charge carrier kinetics, transport, and recombination properties of both types of films are also analyzed using optical pump terahertz probe spectroscopy and time resolved microwave conductivity. The first CBGSe prototype solar cells using chemical bath deposited CdS as a buffer layer show a maximum of 1.5 efficiency with amp; 8764;0.62 V open circuit voltage. The measured properties point to possible limiting factors for CBGSe and related films for PV and optoelectronics and provide insights on possible approaches for improvement within this multinary chalcogenide famil

Conformal monolayer contacts with lossless interfaces for perovskite single junction and monolithic tandem solar cells

The rapid rise of perovskite solar cells PSCs is increasingly limited by the available charge selective contacts. This work introduces two new hole selective contacts for p i n PSCs that outperform all typical p contacts in versatility, scalability and PSC power conversion efficiency PCE . The molecules are based on carbazole bodies with phosphonic acid anchoring groups and can form self assembled monolayers SAMs on various oxides. Besides minimal material consumption and parasitic absorption, the self assembly process enables conformal coverage of arbitrarily formed oxide surfaces with simple process control. The SAMs are designed to create an energetically aligned interface to the perovskite absorber without non radiative losses. For three different perovskite compositions, one of which is prepared by co evaporation, we show dopant , additive and interlayer free PSCs with stabilized PCEs of up to 21.1 . Further, the conformal coverage allows to realize a monolithic CIGSe perovskite tandem solar cell with as deposited, rough CIGSe surface and certified efficiency of 23.26 on an active area of 1 cm2. The simplicity and diverse substrate compatibility of the SAMs might help to further progress perovskite photovoltaics towards a low cost, widely adopted solar technolog