380,718 research outputs found
Experimental setup to fabricate Rb-Xe gas cells for atom spin gyroscopes
No full textAn experimental setup to fabricate atomic vapor cells for atom spin gyroscope application, containing Rb-87, Xe-129, Xe-131, N-2, and H-2, is described. The setup comprises a high-vacuum chamber, an Rb-87 ampule, a glass cell, gas lines, and a turbopump. First, the glass cell is baked for a week at 450 degrees C to reduce outgassing from the inner walls of the glass cell. Next, rubidium atoms are evaporated into the cubic glass cell. Then, the cubic glass cell is cooled to 2 degrees C to increase the amount of Rb-87 in the cubic glass cell while the vacuum chamber is heated to 100 degrees C. 6 Torr of Xe-129, 48 Torr of Xe-131, 140 Torr of N-2, and 24 Torr of H-2 are injected into the cubic glass cell. The sealing method employs pinch-off glass welding. The transverse spin relaxation times of Xe-129 and Xe-131 at a magnetic field of 6.2 mu T applied to the quantization axis are measured to be 8.1 and 16.5 s, respectively, at a cell temperature of 96 degrees C using nuclear magnetic resonance spectroscopy. The pressure ratio between Xe-129 and Xe-131 is determined by comparing the output signals from our atom spin gyroscope. The signal-to-noise ratios are 2500 for Xe-129 and 3333 for Xe-131, respectively, and the expected angular random walk of the atom spin gyroscope is 0.062 degrees/h(1/2) with a 1-Hz repetition rate. (c) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Hot ductility behavior of a high alloy steel
No full textHot ductility behaviour is studied in a cast steel at the intermediate temperature range. A low carbon cast steel is heated to 1,673K (1,400 degrees C) and cooled to 673-873K at the heating and cooling rate of 10K/s. Tensile test is performed at the target temperature. Ductility decreases abruptly, shows the lowest at 823K (550 degrees C), and then recovers gradually as the tensile testing temperature decreases. Fracture surface shows the intergranular fracture with small craters at 823K. Further study on the fracture behaviour reveals that the upper bainite structure existing the cementite at the prior austenite grain boundary is crucial for the embrittlement. Segregated phosphorus triggers the initial micro-crack generation at the grain boundary cementite/matrix interface. Detailed embrittlement mechanism and the fabrication way for sound cast iron are discussed.11Nsciescopu
Decreased phosphorylation of STAT-1, STAT-4 and cytokine release in MDR-TB patients with primary resistance
No full textSETTING: We recently showed that treatment failure rate was higher among multidrug-resistant tuberculosis (MDR-TB) patients without a previous history of tuberculosis (TB) treatment, or so-called 'primary resistance'. OBJECTIVE: To investigate the phosphorylation levels of signal transducers and activators of transcription-1 (STAT-1) and STAT-4 and the subsequent cytokine release as a possible cause of a poor prognosis in MDR-TB patients with primary resistance. DESIGN: Ten patients with successfully treated pulmonary TB without resistance, 12 MDR-TB patients with acquired resistance and 10 MDR-TB patients with primary resistance were enrolled. After 24 h stimulation of peripheral blood mononuclear cells (PBMC) with interferon-gamma (IFN-gamma), interleukin-12 (IL-12), purified protein derivative (PPD), or lysate of Mycobacterium tuberculosis, flow cytometric analysis of intracellular pSTAT-1 and pSTAT-4 were performed and secretion of IFN-gamma, IL-12p40 and tumour necrosis factor-alpha (TNF-alpha) was measured in culture supernatant. RESULTS: The mean fluorescent intensities of pSTAT-1 and pSTAT-4 in PBMC of MDR-TB patients with primary resistance decreased on stimulation of IFN-gamma, PPD or lysate of M. tuberculosis when compared with patients with acquired resistance. In addition, secretion of IFN-gamma, IL-12p40 and TNF-alpha in these patients decreased on various stimuli. CONCLUSION: Decreased phosphorylation of STAT-1, STAT-4, and of subsequent cytokine release, might be associated with a poor prognosis in MDR-TB patients with primary resistance.N
Terahertz electromagnetic interference shielding using single-walled carbon nanotube flexible films
No full textWe performed time-domain terahertz spectroscopy on thin layers of single-walled carbon nanotubes (SWCNTs) coated on flexible films. The SWCNT layers demonstrate good shielding of electromagnetic waves in the terahertz range while maintaining good transparency for visible light. The shielding efficiency can be engineered through the thickness control and/or chemical treatment of SWCNT layers. The frequency-dependent dielectric constants of SWCNT layers are in good agreement with the Drude free-electron model
Concurrent Fabry disease and IgA nephropathy in a patient with Crohn's disease: A case report
No full textWe present a unique case of concurrent Fabry disease (FD) and IgA nephropathy (IgAN) in a 27-year-old female with a 10-year history of Crohn's disease (CD). The patient presented to the nephrology clinic with microscopic haematuria and proteinuria on routine tests. A kidney biopsy revealed mesangial matrix widening, mesangial cell proliferation, and podocyte enlargement with prominent lacy and clear cytoplasm, as observed with haematoxylin and eosin staining. Immunofluorescence staining demonstrated diffuse immunoglobulin A deposits in the mesangium. Electron microscopy identified myelin-like figures in the cytoplasm of podocytes and electron-dense deposits in the mesangium, confirming IgAN and suggesting FD. Subsequent testing showed low alpha-galactosidase A (α-gal) enzyme activity in the patient's white blood cells, confirming the FD diagnosis. Enzyme replacement therapy was initiated following the diagnosis. To our knowledge, this is the first reported case of the coexistence of FD, IgAN, and CD in a single patient. This case highlights the importance of considering FD in patients with proteinuria, emphasising the need for comprehensive diagnostic evaluations in complex cases
sj-docx-1-jom-10.1177_01492063221125143 - Supplemental material for Employer-Sponsored Career Development Practices and Employee Performance and Turnover: A Meta-Analysis
No full textSupplemental material, sj-docx-1-jom-10.1177_01492063221125143 for Employer-Sponsored Career Development Practices and Employee Performance and Turnover: A Meta-Analysis by Thomas W. H. Ng, Frederick H. K. Yim, Haoyang Chen and Yinuo Zou in Journal of Management</p
Fast-Synthesis of alpha-Phosphonyloxy Ketones as Drug Scaffolds in a Capillary Microreactor
No full textA simple, room temperature approach for the fast single-step synthesis of alpha-phosphonyloxy ketone, a drug scaffold, has been developed which involves highly reactive species i.e., 1,2-dicarbonyls that readily react with trialkyl phosphites and formic acids in batch as well as in continuous-flow with the flow rate of 3 ml/min (t (R) = similar to 4 s). The present approach reduced the synthesis time from hours to minutes in batch, which was further lowered to a few seconds precisely controlled by single capillary microfluidics. A wide range of 1,2-dicarbonyl derivatives were smoothly transformed to their corresponding alpha-phosphonyloxy ketones in moderate to good yields (50-82 %) under optimized flow-reaction conditions. Further, the alpha-phosphonyloxy ketones produced can be utilized in batch process to form benzoin, oxazole core, and alpha,alpha '-diarylated carbonyl compounds in 82 %, 50 %, and 54 % yields, respectively, which are alternative key precursors/scaffolds of natural products and active pharmaceutical ingredients (APIs).11Nsciescopu
Correlation between the bath composition and nanoporosity of DC-electrodeposited Ni-Fe alloy
No full textThe outstanding mechanical strength of as-deposited DC-electrodeposited nanocrystalline (nc) Ni-Fe alloys has been the subject of numerous researches in view of their scientific and practical interest. However, recent studies have reported a dramatic drop in ductility upon annealing above 350°C, associated with a concomitant abnormal rapid grain growth. The inherent cause has been ascribed to the presence of a detrimental product or by product in the bath, which affects either the microstructure or causes defects in the concentration and/or distribution of the as-deposited films. The present work has been inspired by the observed abnormal behaviour of annealed electrodeposited nc Ni-Fe alloy, which has here been addressed by considering the relationship between the composition of the bath (iron-chloride, nickel-sulphate solution, saccharin and ascorbic acid) and deposition defects (e.g. grain boundary pores) in the case of an nc Ni-Fe (Fe 48 wt%) alloy. The current investigations have included X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) in both as-deposited and post-annealed conditions (300°C–400°C). XPS depth profiling with Ar ion sputtering showed a significant amount of C and O impurities entrapped in the foils during deposition. As such impurities are often overlooked in common analytical techniques, new scenarios may need to be rationalised to explain the observed drop in tensile ductility of the as-deposited Ni-Fe alloys
Unexpected Results of a Political Pilgrimage: Yim Su-gyong&amp;apos;s 1989 Trip to North Korea and Changes in North Koreans&amp;apos; Worldview
No full textThis article deals with the impact on the North Korean domestic situation produced by the 1989 visit to Pyongyang by Yim Su-gyong, a young student activist from South Korea. Going there in defiance of South Korea&amp;apos;s official policy, she was enthusiastically welcomed by the North Korean authorities, who strove to present her as an embodiment of the alleged revolutionary spirit of South Korean youngsters. However, in the long run Yim&amp;apos;s trip produced totally different results. The North Korean audience, fascinated with Yim Sugyong and quite attentive to her behavior, was able to read hints that indicated the official picture of South Korean life as presented by the North Korean media was wrong. Contrary to the authorities&amp;apos; initial expectations, the trip made North Koreans more skeptical of the officially approved worldview
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