Search

Investigates the surface electric field of silicon delta-doped GaAs grown by molecular beam epitaxy at a low substrate temperature using photoreflectance spectroscopy. Observations on Franz-Keldysh oscillations in the reflectance spectra; Explanation for the evolution of photoreflectance spectra; Use of photoreflectance in the study of semiconductors.

Focuses on a study which characterized the redistribution of arsenic precipitates in silicon δ-doped gallium arsenide through x-ray diffractometry and transmission electron microscopy. Experimental details; Results and discussion; Conclusion.

The study attempts to investigate factors affecting the semester break and dropouts in a case University in order to achieve maximum retention and graduation rates. The data were collected from the official records of the day system of the 22 Departments in five colleges in two semesters. Also, we collected 2,402 records of grade point average of different curricula in different classes in May and November. Then basic statistical analyses of semester break and dropouts, retention rates, correlation, and logistic regression were carried out. Results showed that 'Interest' and 'Learning' problems influenced students' retention or dropout in the case University. From logistic regression, college, teacher, and attribute of the curriculum were found to be significant factors in prediction of the pass model. The study has significance to educators in determining factors influencing semester break, dropout, retention, and graduation rates in the university to achieve the maximum performance. [ABSTRACT FROM AUTHOR]

A significant dropout rate of freshmen in university X during 2011-15 prompted us to carry out the present study to detect freshmen's attitudes and learning preferences. Holland's theory of six personality types: Realistic, Investigative, Artistic, Social, Enterprising, and Conventional was applied. The survey includes data from 1,558 freshmen from five colleges. The survey questionnaire had 194 items. The analysis showed Realistic and Investigative types were significant in males while Artistic and Social types were more projecting in females. Also, it revealed poor Person-Environment congruence and learning performance in the College of Science and Engineering. The students at risk need a transfer to another major or subject of their interest. Besides, differentiating instruction for customized service will satisfy the real demand and solve the thorny dropout problems. By data mining, all students at risk were advised to four channels for appropriate actions. The outcome of this study offers directions to low GPA students through psychological and physical assessments. [ABSTRACT FROM AUTHOR]

A technique that can reliably monitor exercise intensity plays an important role for the effectiveness and safety of an exercise prescription. A universal algorithm for the recursive estimation of exercise rate during a variety of aerobic exercises using measurements from a body-mounted triaxial accelerometer (TA) is proposed. Information about the type of exercise is not required by the algorithm and the TA can be mounted at the same location regardless of the exercise type. The algorithm involves period detection and data fusion. Experimental results demonstrate that the algorithm is effective for common aerobic exercises. [ABSTRACT FROM AUTHOR]

Essentials The pathogenesis of immune thrombocytopenia (ITP) has not been fully clarified. We analyzed the role of anti-αvβ3 autoantibody in the pathogenesis of ITP in patients. Anti-αvβ3 autoantibody impeded megakaryocyte migration and adhesion to the vascular niche. Anti-α v β 3 autoantibody potentially contributes to the pathogenesis of refractory ITP., Summary: Background The pathogenesis of immune thrombocytopenia (ITP) has not been fully clarified. Anti-αvβ3 integrin autoantibody is detected in chronic ITP patients, but its contribution to ITP is still unclear. Objectives To clarify the potential role of anti-αvβ3 integrin autoantibody in chronic ITP and the related mechanism. Methods Relationship between levels of anti-αvβ3 autoantibody and platelets in chronic ITP patients was evaluated. The influence of anti-αvβ3 antibody on megakaryocyte (MK) survival, differentiation, migration and adhesion was assessed, and the associated signal pathways were investigated. Platelet recovery and MKs' distribution were observed in an ITP mouse model pretreated with different antibodies. Result In this study, we showed that the anti-αvβ3 autoantibody usually coexists with anti-αIIbβ3 autoantibody in chronic ITP patients, and patients with both autoantibodies have lower platelets. In in vitro studies, we showed that the anti-αvβ3 antibody had no significant effect on the survival and proliferation of MKs, whereas it decreased formations of proplatelet significantly. Anti-αvβ3 antibody impeded stromal cell derived facor-1 alpha (SDF-1α)- mediated migration and inhibited the phosphorylation of protein kinase B. Anti-αvβ3 antibody significantly inhibited MKs' adhesion to endothelial cells and Fibrogen. The phosphorylation of focal adhesion kinase and proto-oncogene tyrosine-protein kinase Src induced by adhesion was inhibited when MKs were pretreated with anti-αvβ3 antibody. In in vivo studies, we showed that injection with anti-α v antibody delayed platelet recovery in a mouse model of ITP. Conclusions These findings demonstrate that the autoantibody against integrin α v β 3 may aggravate thrombocytopenia in ITP patients by impeding MK migration and adhesion to the vascular niche, which provides new insights into the pathogenesis of ITP., (© 2018 International Society on Thrombosis and Haemostasis.)

Autoimmune diseases have been implicated in the development of intrinsic asthma, however little data are available on the role of autoimmunity in the pathogenesis of asthma. The purpose of this study was to investigate circulating autoantibodies against the high-affinity receptor for immunoglobulin E, FcepsilonRI, in patients with asthma. Seventy-eight patients with asthma and 32 healthy control subjects were included. All individuals were tested using a triple-staining flow cytometry-based basophil activation test (BAT) for the potential presence of autoantibodies against FcepsilonRI. Of the 78 asthma patients, 29 (37.2%) had a positive BAT result, indicating that their serum was able to activate basophils, compared with only four (12.5%) of the control group, a statistically significant between-group difference. These data suggest that some asthma patients have aberrant anti-FcepsilonRI autoantibodies, which implies that autoimmunity may be one factor involved in the pathogenesis of intrinsic asthma.

In order to obtain an in vitro system for studying the mechanism of persistent infection of fish nodavirus, a novel cell line (BB) was established from the brain tissue of a barramundi, Lates calcarifer, which had survived viral nervous necrosis disease. The cell line has been subcultured > 100 times. The persistence of fish nodavirus designated as barramundi brain nervous necrosis virus (BBNNV) in the BB cells was demonstrated by: (1) the detection of the infectious virus in the culture supernatants, (2) the detection of NNV nucleic acids extracted from the BB cells, (3) the positive result of immunochemical staining using an NNV-specific monoclonal antibody and (4) their resistance to infection by another fish nodavirus grouper NNV (GNNV). No temperature-sensitive mutants were detected in the culture supernatant of the BB cells. Neither truncated genome (RNA1 or RNA2) nor smaller coat protein was found in the purified BBNNV particles, suggesting that defective interfering particles were unlikely to be important in the NNV-persistent infection in the BB cells. The result of the neutralization test indicated that the 5 antigenic determinants, recognized by GNNV-specific neutralizing antibodies, also existed on the coat protein of BBNNV. The BB cell line is the first cell line reported to be persistently infected with NNV, and would be a useful model for understanding the mechanisms of NNV-persistent infection in vitro and in vivo.

Objective: To study the chemical constituents of Carduus crispus., Method: Using chromatographic methods to isolate compounds and using chemical and spectral methods to elucidate the structures of the isolated compounds., Result: Eight compounds were elucidated as beta-amyrin palmitate, taraxastery acetate, luteolin-7-O-alpha-L-rhamanopyranosyl-(1-->2)-beta-D-glucopyranoside, luteolin-7-O-beta-D-glucopyranoside, triacontanic acid, beta-sitosterol, stigmasterol and stigmast-7-en-3 beta-ol., Conclusion: All the compounds were obtained from this plant for the first time.

To observe the changes in aldosterone binding activity of kidney cytosols after pathological stress in rats and the regulation, binding capacity (Rt) and apparent dissociation constant (Kd) of aldosterone binding activity of kidney cytosols in normal, low-degree or heavy-degree scalded rats were measured by radioligand binding assay using [3H]aldosterone as the ligand. Changes in Rt and Kd of aldosterone binding activity were observed after injection of anti-rat TNF alpha and IL-1 beta antibodies, alpha-melanocyte-stimulating hormone (alpha-MSH) and KPV peptide (Ac-D-Lys-L-Pro-D-Val). The results indicated that there were two types of aldosterone binding activities in kidney cytosol with different Rt and Kd, and the Rt of heavy-degree scalded rats (Rt1: 22.4 +/- 5.4 fmol/mg pro, Rt2: 196.3 +/- 32.5 fmol/mg pro) was lower than that of the control group (Rt1: 41.6 +/- 7.2 fmol/mg pro, Rt2: 317.6 +/- 70.0 fmol/mg pro) (P < 0.01; P < 0.01); while the Rt of low-degree scalded rats (Rt1: 41.4 +/- 5.0 fmol/mg pro, Rt2: 314.8 +/- 45.7 fmol/mg pro) was not significantly different from that of the control group (P > 0.05; P > 0.05). Injection of anti-rat TNF alpha and IL-1 beta antibodies, alpha-MSH and KPV prevented Rt of aldosterone binding activity from decrease in kidney cytosol of rats with heavy-degree scald. These findings suggest that aldosterone binding activity may be down-regulated in heavy-degree scalded rats, but it may be reversed by injection of anti-rat TNF alpha and IL-1 beta antibodies, alpha-MSH and KPV.

A series of diquaternary dipiperazinium salts containing dithiocarboxyl groups 6a-f and 9 were synthesized and evaluated for their analgesic and sedative activities. The result showed that the presence of two quaternary ammonium cations and the distance between them are very important for the activities of the salts. Compound 6b exhibited the best activities (at dose 2 mg/kg, analgesic, 57%; sedative, 59%) among compounds 6a-f. Compound 9 not only showed the most potent analgesic (85.4%, dose 1 mg/kg) and sedative (93.1%, dose 1 mg/kg) activities, but also exhibited anticancer activity against KB (68.7%, dose 10 microM).

Aim: To synthesize piperazine derivatives and screen anti-tumor compounds with higher activity and lower toxicity., Methods: Selecting 1,4-bis(3-bromopropionyl)piperazine as leading compound, a series of 1,4-bis[3-(amino-dithiocarboxy)propionyl] piperazine derivatives (4a-j) were synthesized through the use of aminodithiocarboxylate. All the synthetic compounds (4a-j) were tested for their anti-tumor activity against eight kinds of tumor cells., Results: Compounds (4a-j) are new compounds, among them, compounds 4c, 4d and 4e showed anti-tumor activity against HL-60. The inhibition of compounds 4c, 4d and 4e against HL-60 are 44%, 90% and 70% respectively, at the concentration of 10 mumol.L-1. However, the inhibition of the other kinds of anti-tumor cells are not distinctive., Conclusion: These results suggest that this may be one of the effective routes to improve the anti-tumor activity and reduce the toxicity of 1,4-bis(3-bromopropionyl)piperazine.