166 research outputs found
Spectrally Resolved Transmission Cathodoluminescence Evaluation of Vertical Cavity Surface Emitting Lasers
We describe an inexpensive addition to an existing cathodoluminescence system: Spectrally resolved transmission cathodoluminescence (SRTCL). In this technique, we couple the light emerging from beneath the sample into a vacuum compatible fiber optic cable for spectral dispersion by a conventional spectrometer. This simple approach represents a new development in the area of cathodoluminescence characterization. This exploratory study describes the preliminary results of this effort. We have applied SRTCL to the evaluation of InGaAs quantum wells, grown by molecular beam epitaxy, in vertical cavity surface emitting lasers. Results thus far support the viability of the technique. We also discuss the difficulties experienced to date and provide suggestions for future system improvements
OS VENTOS QUE SOPRARAM DO LESTE: O PCB ENTRE O FIM DA HISTĂRIA E O MARXISMO
Este artigo tem como objeto comparar a luta polĂtico-ideolĂłgica ocorrida no PCB e que gerou a criação do PPS, com o processo de mudanças manifestas na antiga URSS e no Leste Europeu. Visto de forma dialĂ©tica, o impacto de tais mudanças, associado Ă dinĂąmica histĂłrica do Brasil nos anos 80 do sĂ©culo XX, resulta em caminhos distintos para os comunistas brasileiros que desembocam na divisĂŁo em dois partidos
Protein kinase Ymr291w/Tda1 is essential for glucose signaling in Saccharomyces cerevisiae on the level of hexokinase isoenzyme ScHxk2 phosphorylation
The enzyme ScHxk2 of Saccharomyces cerevisiae is a dual-function hexokinase that besides its catalytic role in glycolysis is involved in the transcriptional regulation of glucose-repressible genes. Relief from glucose repression is accompanied by the phosphorylation of the nuclear fraction of ScHxk2 at serine 15 and the translocation of the phosphoenzyme into the cytosol. Different studies suggest different serine/threonine protein kinases, Ymr291w/Tda1 or Snf1, to accomplish ScHxk2-S15 phosphorylation. The current paper provides evidence that Ymr291w/Tda1 is essential for that modification while protein kinases Ydr477w/Snf1, Ynl307c/Mck1, Yfr014c/Cmk1 and Ykl126w/Ypk1, which co-purified during Ymr291w/Tda1 tandem affinity purification, as well as protein kinases PKA and PKB homolog Sch9 are dispensable. Taking into account the detection of a significantly higher amount of the Ymr291w/Tda1 protein in cells grown in low-glucose media as compared to a high-glucose environment, Ymr291w/Tda1 is likely to contribute to glucose signaling in Saccharomyces cerevisiae on the level of ScHxk2-S15 phosphorylation in a situation of limited external glucose availability. The evolutionary conservation of amino acid residue serine 15 in yeast hexokinases and its phosphorylation is illustrated by the finding that YMR291W/TDA1 of Saccharomyces cerevisiae and the homologous KLLA0A09713 gene of Kluyveromyces lactis allow for cross-complementation of the respective protein kinase single-gene deletion strains
Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(II) and palladium(II).
The synthesis, spectroscopic and X-ray structural characterization of copper(II) and palladium(II) complexes with aziridine ligands as 2-dimethylaziridine HNCH2CMe2 (a), the bidentate N-(2-aminoethyl)aziridines C2H4NC2H4NH2 (b) or CH2CMe2NCH2CMe2NH2 (c) as well as the unsaturated azirine NCH2CPh (d) are reported. Cleavage of the cyclometallated Pd(II) dimer [ÎŒ-Cl(C6H4CHMeNMe2-C,N)Pd]2 with ligand a yielded compound [Cl(NHCH2CMe2)(C6H4CHMe2NMe2-C,N)Pd] (1a). The reaction of the aziridine complex trans-[Cl2Pd(HNC2H4)2] with an excess of aziridine in the presence of AgOTf gave the ionic chelate complex trans-[(C2H4NC2H4NH2-N,NâČ)2Pd](OTf)2 (2b) which contains the new ligand b formed by an unexpected insertion and ring opening reaction of two aziridines (âaziridine dimerizationâ). CuCl2 reacted in pure HNC2H4 or HNCH2CMe2 (b) again by âdimerizationâ to give the tris-chelated ionic complex [Cu(C2H4NC2H4NH2-N,NâČ)3]Cl2 (3b) or the bis-chelated complex [CuCl(C2H2Me2NC2H2Me2NH2-N,NâČ)2]Cl (4c). By addition of 2H-3-phenylazirine (d) to PdCl2, trans-[Cl2Pd(NCH2CPh)2] (5d) was formed. All new compounds were characterized by NMR, IR and mass spectra and also by X-ray structure analyses (except 3b). Additionally the cytotoxic effects of these complexes were examined on HL-60 and NALM-6 human leukemia cells and melanoma WM-115 cells. The antimicrobial activity was also determined. The growth of Gram-positive bacterial strains (S. aureus, S. epidermidis, E. faecalis) was inhibited by almost all tested complexes at the concentrations of 37.5â300.0 ÎŒg mLâ1. However, MIC values of complexes obtained for Gram-negative E. coli and P. aeruginosa, as well as for C. albicans yeast, mostly exceeded 300 ÎŒg mLâ1. The highest antibacterial activity was achieved by complexes 1a and 2b. Complex 2b also inhibited the growth of Gram-negative bacteria.
Graphical abstract: Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(ii) and palladium(ii
Phase II study of capecitabine and oxaliplatin given prior to and concurrently with preoperative pelvic radiotherapy in patients with locally advanced rectal cancer
This multicentre phase II study evaluated the efficacy and safety of preoperative capecitabine plus oxaliplatin and radiotherapy (RT) in patients with locally advanced rectal cancer (T3/T4 rectal adenocarcinoma with or without nodal involvement). Treatment consisted of one cycle of XELOX (capecitabine 1000âmgâmâ2 bid on days 1â14 and oxaliplatin 130âmgâmâ2 on day 1), followed by RT (1.8âGy fractions 5 days per week for 5 weeks) plus CAPOX (capecitabine 825âmgâmâ2 bid on days 22â35 and 43â56, and oxaliplatin 50âmgâmâ2 on days 22, 29, 43 and 50). Surgery was recommended 5 weeks after completion of chemoradiotherapy. The primary end point was pathological complete tumour response (pCR). Sixty patients were enrolled. In the intent-to-treat population, the pCR rate was 23% (95% CI: 13â36%). 58 patients underwent surgery; R0 resection was achieved in 57 (98%) patients, including all 5 patients with T4 tumours. Sphincter preservation was achieved in 49 (84%) patients. Tumour and/or nodal downstaging was observed in 39 (65%) patients. The most common grade 3/4 adverse events were diarrhoea (20%) and lymphocytopaenia (43%). Preoperative capecitabine, oxaliplatin and RT achieved encouraging rates of pCR, R0 resection, sphincter preservation and tumour downstaging in patients with locally advanced rectal cancer
Response to comment on 'Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity'
Lambert et al. question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm that our study provides unambiguous evidence that chytridiomycosis has affected at least 501 amphibian species
Diffusion of Zn into GaAs and AlGaAs from isothermal Liquid-phase epitaxy solutions
In this work we present results of zinc diffusion in GaAs using the liquid phase epitaxy technique from liquid solutions of GaâAsâZn and GaâAsâAlâZn. Using siliconâdoped nâGaAs substrates, working at a diffusion temperature of 850â°C, and introducing a dopant concentration ranging 1018â1019 cmâ3, the most important findings regarding the diffusion properties are as follows: (a) zinc concentration in the solid depends on the square root of zinc atomic fraction in the liquid; (b) the diffusion is dominated by the interstitialâsubstitutional process; (c) the diffusivity D varies as about C3 in the form D=2.9Ă10â67C3.05; (d) aluminum plays the role of the catalyst of the diffusion process, if it is introduced in the liquid solution, since it is found that D varies as (ÎłAsXlAs)â1; (e) the zinc interstitial is mainly doubly ionized (Zn++i); (f) the zinc diffusion coefficient in Al0.85 Ga0.15 As is about four times greater than in GaAs; (g) by means of all these results, it is possible to control zinc diffusion processes in order to obtain optimized depth junctions and doping levels in semiconductor device fabrication
Long-term results of radiotherapy for periarthritis of the shoulder: a retrospective evaluation
<p>Abstract</p> <p>Background</p> <p>To evaluate retrospectively the results of radiotherapy for periarthritis of the shoulder</p> <p>Methods</p> <p>In 1983â2004, 141 patients were treated, all had attended at least one follow-up examination. 19% had had pain for several weeks, 66% for months and 14% for years. Shoulder motility was impaired in 137/140 patients. Nearly all patients had taken oral analgesics, 81% had undergone physiotherapy, five patients had been operated on, and six had been irradiated. Radiotherapy was applied using regular anterior-posterior opposing portals and Co-60 gamma rays or 4 MV photons. 89% of the patients received a total dose of 6 Gy (dose/fraction of 1 Gy twice weekly, the others had total doses ranging from 4 to 8 Gy. The patients and the referring doctors were given written questionnaires in order to obtain long-term results. The mean duration of follow-up was 6.9 years [0â20 years].</p> <p>Results</p> <p>During the first follow-up examination at the end of radiotherapy 56% of the patients reported pain relief and improvement of motility. After in median 4.5 months the values were 69 and 89%, after 3.9 years 73% and 73%, respectively. There were virtually no side effects. In the questionnaires, 69% of the patients reported pain relief directly after radiotherapy, 31% up to 12 weeks after radiotherapy. 56% of the patients stated that pain relief had lasted for "years", in further 12% at least for "months".</p> <p>Conclusion</p> <p>Low-dose radiotherapy for periarthropathy of the shoulder was highly effective and yielded long-lasting improvement of pain and motility without side effects.</p
Use of IFN gamma/IL10 Ratio for Stratification of Hydrocortisone Therapy in Patients With Septic Shock
Large clinical trials testing hydrocortisone therapy in septic shock have produced conflicting results. Subgroups may benefit of hydrocortisone treatment depending on their individual immune response. We performed an exploratory analysis of the database from the international randomized controlled clinical trial Corticosteroid Therapy of Septic Shock (CORTICUS) employing machine learning to a panel of 137 variables collected from the Berlin subcohort comprising 83 patients including demographic and clinical measures, organ failure scores, leukocyte counts and levels of circulating cytokines. The identified theranostic marker was validated against data from a cohort of the Hellenic Sepsis Study Group (HSSG) (n = 246), patients enrolled in the clinical trial of Sodium Selenite and Procalcitonin Guided Antimicrobial Therapy in Severe Sepsis (SISPCT, n = 118), and another, smaller clinical trial (Crossover study, n = 20). In addition, in vitro blood culture experiments and in vivo experiments in mouse models were performed to assess biological plausibility. A low serum IFNÎł/IL10 ratio predicted increased survival in the hydrocortisone group whereas a high ratio predicted better survival in the placebo group. Using this marker for a decision rule, we applied it to three validation sets and observed the same trend. Experimental studies in vitro revealed that IFNÎł/IL10 was negatively associated with the load of (heat inactivated) pathogens in spiked human blood and in septic mouse models. Accordingly, an in silico analysis of published IFNÎł and IL10 values in bacteremic and non-bacteremic patients with the Systemic Inflammatory Response Syndrome supported this association between the ratio and pathogen burden. We propose IFNÎł/IL10 as a molecular marker supporting the decision to administer hydrocortisone to patients in septic shock. Prospective clinical studies are necessary and standard operating procedures need to be implemented, particularly to define a generic threshold. If confirmed, IFNÎł/IL10 may become a suitable theranostic marker for an urging clinical need
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