Eu...-activated borogermanate scintillating glasses with compositions of 25B...O...-40GeO...-25Gd...O...-(10-x)La...O...-xEu...O... were prepared by melt-quenching method. Their optical properties ...were studied by transmittance, photoluminescence, Fourier transform infrared (FTIR), Raman and X-ray excited luminescence (XEL) spectra in detail. The results suggest that the role of Gd...O... is of significance for designing dense glass. Furthermore, energy-transfer efficiency from Gd... to Eu... ions can be near 100% when the content of Eu...O... exceeds x = 4, the corresponding critical distance for Gd...-Eu... ion pairs is estimated to be 4.57 ... The strongest emission intensities of Eu... ions under both 276 and 394 nm excitation are simultaneously at the content of 8 mol% Eu...O... The degree of Eu-O covalency and the local environment of Eu... ions are evaluated by the value of ...t parameters from Judd-Ofelt analysis. The calculated results imply that the covalency of Eu-O bond increases with the increasing concentration of Eu... ions in the investigated borogermanate glass. As a potential scintillating application, the strongest XEL intensity under X-ray excitation is found to be in the case of 6 mol% Eu2O3, which is slightly different from the photoluminescence results. The possible reason may be attributed to the discrepancy of the excitation mechanism between the ultraviolet and X-ray energy. (ProQuest: ... denotes formulae/symbols omitted.)
Trehalose-6-phosphate synthase, a key enzyme in trehalose synthesis pathway of plant, plays an important role in response to abiotic stress in xerophilous rock lily and other resurrection plants. In ...this study, homologous amplification and RACE technique were used to clone gene SpTPS1 for trehalose-6-phosphate synthase from Selaginella pulvinata, which is an endemic xerophilous plant in China. The full-length cDNA is 3223 bp long, containing an open reading frame (ORF) of 2790 bp. Protein sequence comparison showed that the pupative amino acid sequence of this ORF shares high similarity to trehalose-6-phosphate synthases of mode species, especially at the conserved sites of catalytic activity centers. Yeast functional complementation test showed that trehalose-6-phosphate synthase mutant (tps1 big up tri, open), transformed by the ORF of SpTPS1 gene, can restore growth on the medium supplemented with glucose as a sole carbon source. This result indicated that SpTPS1 of S. pulvinata encodes for an active protein and is hopeful to be applied in transgenic improvement of abiotic stress tolerance in plant.
A search has been made for a steady emission of VHE or UHE gamma rays from the Crab Nebula, Cygnus X-3, and Hercules X-1 using the data obtained from June 1990 to January 1992 with the Tibet Air ...Shower Array. No dc excess is found from the three sources in this period. Stringent flux upper limits obtained in the 10-TeV energy region place restrictions on the acceleration process of high-energy cosmic rays near discrete point sources. (C.D.)
BACKGROUNDSinistral portal hypertension associated with pancreatic pseudocysts is rare, often caused by extrinsic compression of splenic vein, the follow-up examinations by ultrasonography for early ...diagnosis are quietly necessary since haematemesis, a life-threatening condition. Few studies have reported the ultrasonography findings of sinistral portal hypertension. CASE SUMMARYA 52-year-old man presented with acute abdominal pain after drinking, steatorrhea, weight loss and accidentally melena in the past 2 mo. He underwent ultrasound-guided fine needle aspiration in other hospital and diagnosed with pancreatic pseudocysts. Ultrasonography imaging, in our department, appeared as cystic heterogeneous hypoechoic area with the size of 4.7 cm × 3.8 cm that located posterior to the body and tail of pancreas, adjacent to splenic vein associated with thrombosis resulted from compression. Spleen incrassated to approximately 7.3 cm, but no dilation of main portal vein was presented. Color Doppler Flow Imaging demonstrated the formation of splenic venous collateral, nevertheless no significantly flow signals was observed in splenic vein. Pulsed Doppler revealed that the peak velocity of splenic venous collateral was 18.4 cm/s with continuous waveform. Laparotomy confirmed sinistral portal hypertension associated with pancreatic pseudocysts, subsequently distal pancreatectomy combined with splenectomy and partial gastrectomy was performed. CONCLUSIONIt's important clinically to know the ultrasound appearance of sinistral portal hypertension associated with pancreatic pseudocysts for sonographer and physician.
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