Search

This study investigated the controllable fabrication of anisotropic particles with different sizes and morphologies via self-assembly and photoinduced deformation of azo colloidal microspheres, which were formed from a typical azo molecular material (IAC-4) that contains a 1,4,3,6-dianhydrosorbitol core and the cinnamate peripheral groups. Firstly, azo colloidal microspheres were obtained by self-assembly via gradually adding deionized water into IAC-4 solution of tetrahydrofuran. For precisely controlling the length of short axis of anisotropic particles, IAC-4 colloidal microspheres with different and uniform sizes were obtained by adjusting the IAC-4 concentration, adding rate of water and stirring rate. The size of colloidal microspheres becomes smaller with the increase in IAC-4 concentration, the adding rate of water and the stirring rate. Finally, IAC-4 colloidal microspheres in the solid state, perpendicularly irradiated by the linearly polarized laser beam (λ = 488 nm), were irreversibly and controllably stretched into anisotropic particles with the different morphologies, length of long axis and axial ratio via adjusting the irradiation time and the power of laser beam. [ABSTRACT FROM AUTHOR]

Voids usually have a detrimental effect on the performance of carbon fiber reinforced polymer (CFRP). This paper presents a nonlinear dynamic method, known as recurrence quantification analysis (RQA), for the identification of localized void defects. First, five standard CFRP specimens with known porosity ranging from 0.2 to 5.94% are tested using ultrasonic pulse-echo technique, and the obtained backscattered signals are subsequently analyzed by RQA. The result shows that two RQA characteristic parameters, the recurrence rate and the Shannon entropy, both clearly increase with increasing porosity. Next, the RQA is performed on another CFRP specimen with unknown porosity. Two regions in this specimen containing localized void defects are detected based on the above finding. This result is finally verified by a destructive experiment. The research demonstrates that RQA is an effective new method for the identification of localized void defects in CFRP. [ABSTRACT FROM AUTHOR]

Background: The effect of postoperative chemoradiotherapy (CRT) for esophageal carcinoma (EC) was investigated. Patients who can obtain benefit from this treatment modality have not yet been well identified.Methods: We searched PubMed, Embase, Web of Science, and the Cochrane Library for studies published from January 1993 to July 2016. Research comparing surgery alone (SA) with postoperative CRT in patients with resectable EC was procured; collected articles were written in English.Results: Nine studies comparing of postoperative CRT versus SA (n = 1650) in patients with resectable EC met the inclusion criteria. No survival benefit was achieved for postoperative CRT compared with SA. Subgroup analysis was conducted for patients under resection with positive lymph node carcinoma; there was a significant survival benefit at 1 year [risk ratio (RR) = 0.55 95% CI: 0.37-0.82; P = 0.003], 3 years (RR = 0.71 95% CI: 0.61-0.83; P<0.0001), as well as 5 years (RR = 0.86 95% CI: 0.78-0.94; P = 0.0007). Subgroup analysis by tumor histology of squamous cell carcinoma (SCC) was also performed, but there was no significant survival benefit when postoperative CRT was compared with SA. Fail models after surgery were performed; the RR for local control rate and distant metastasis rate were 0.64 (95% CI 0.49-0.85; P = 0.002) and 0.87 (95% CI 0.67-1.15; P = 0.34), which indicates lower local recurrence rates of post-CRT than that of SA.Conclusion: This meta-analysis demonstrated a survival benefit of postoperative CRT over SA in resectable EC patients with positive lymph nodes. Improvements of local control rates with postoperative CRT were also detected. [ABSTRACT FROM AUTHOR]

Micro defects usually lead to performance degradation of materials. Pulse-echo technique is an effective method of revealing micro defects in materials, and booming in which has been witnessed over the years. However, detection of flaw echoes submerged in intensive noise is challenging. In this paper, a method of flaw echoes detection based on generalized S-transform is proposed. The original signals are transformed to time-frequency domain by generalized S-transform in the first stage. Subsequently, the time-frequency spectrums are enhanced through image segmentation techniques, including global thresholding and dilation. Finally, clear flaw echoes are obtained by inverse generalized S-transform, contributing to further investigation of defects. Both the simulation and experimental results show effectiveness of the flaw echoes detection method. [ABSTRACT FROM AUTHOR]

In order to explore the growth inhibition and physiological responses of unicellular and colonial Microcystis aeruginosa during coexistence with Acorus calamus, algal densities, chlorophyll a contents, exopolysaccharide (EPS) concentrations, malondialdehyde (MDA) contents, catalase (CAT) activities, and peroxidase (POD) activities of the two algae strains were analyzed. Although the unicellular and colonial strains of M. aeruginosa were both inhibited by A. calamus, unicellular algae were more sensitive than the colonial algae. The measurement results for EPS, MDA, CAT, and POD showed that unicellular M. aeruginosa had higher levels of stress related damage than colonial strains when they were exposed to the same density of A. calamus, and the cellular defense system of colonial M. aeruginosa was stronger than that of unicellular M. aeruginosa. Natural blooms of Microcystis are typically composed of colonial forms of M. aeruginosa, therefore future efforts to control such blooms, possibly through the development of new algicides, should focus on the unique characteristics of colonial M. aeruginosa strains. [ABSTRACT FROM AUTHOR]

The IκB kinase (IKK)/NF-κB pathway has been shown to be a major regulator in cell survival. However, the mechanisms through which IKK mediates cell death are not clear. In this study, we showed that IKK-β contributed to hydrogen peroxide (H2O2)-induced cell death independent of the NF-κB pathway. Our results demonstrated that the pro-death function of IKK-β under oxidative stress was mediated by p85 S6K1 (S6 kinase 1), but not p70 S6K1 through a rapamycin-insensitive and mammalian target of rapamycin complex 1 kinase-independent mechanism. We found that IKK-β associated with p85, but not p70 S6K1, which was required for H2O2-induced activation of p85 S6K1. IKK-β and p85 S6K1 contributed to H2O2-induced phosphorylation of Mdm2 (S166) and p53 accumulation. p85 S6K1 is critical for IKK-β-mediated cell death. Thus, these findings established a novel oxidative stress-responsive pathway that involves IKK-β, p85 S6K1 and Mdm2, which is response for H2O2-induced cell death. Our results have important implications for IKK-β and p85 S6K1 as potential targets for the prevention of diseases involved in oxidative stress-induced aberrant cell death. [ABSTRACT FROM AUTHOR]

In this study, the spatial distributions of soil lead (Pb) concentration in three horizontal soils in Guangdong, China, were surveyed and analyzed using geostatistics and geography information systems (GIS). Findings indicated that the Pb geometric mean concentration of 23.3 mg/kg in surface soils was found to be higher than those in global soils, which ranged from 2.3–235 mg/kg. In addition, the Pb geometric mean concentrations from A- to C-horizon were found to be 23.3, 27.2, and 28.6 mg/kg, respectively. The classification of a soil Pb environmental risk in an area was likewise presented based on the different levels of environmental quality of Pb and was done by GIS technology. Accordingly, there is a higher local concentration of Pb in the surrounding areas of Guangzhou where there is higher population density and in the north of Guangdong, which is a historic mining area. The results obtained by the environmental risk assessment reveal that about 46% of total surveyed area was above the background value, that is, 2.7% of the total area was at risk of pollution. [ABSTRACT FROM AUTHOR]

We study the dark current of the GaAs/AlGaAs quantum-well infrared photodetector (QWIP) by assuming a drift-diffusion carrier transport in the barriers where the electric fields are obtained by the current continuity condition and the self-consistent energy band structure. It has been shown that due to the current continuity condition, the dark currents across the QWIP devices are determined by the thermionic emission from the emitter to the multiple quantum well (MQW) region. The self-consistent calculation of the Schrödinger and Poisson equations shows a weak electric field in the barrier region connecting to the emitter (much smaller than the average field across the QWIP at low bias) due to the accumulation of carriers in the triangle quantum well formed at the emitter-MQW interface, which results in a very small dark current at low bias. The numerical results explain well our experimental observation. [ABSTRACT FROM AUTHOR]

Sn3.5Ag4Ti(Ce,Ga) active filler was used for joining alumina with alumina and alumina with copper at 250°C in air. The joining process was done without flux and without the need for pre-metallization of alumina or a protective atmosphere. After mechanical activation of the bonding surfaces of alumina and copper, the filler showed good wetting on both alumina and copper and led to a strong bond between alumina and copper. Through tensile testing, a bonding strength of 23.7 MPa was found in the alumina/copper joint region. The shear strengths for alumina/alumina, copper/copper and alumina/copper joints were 13.5, 14.3, and 10.2 MPa, respectively. The affinity of cerium for oxygen protects titanium from oxidation, giving rise to the reaction of titanium with alumina at such a low temperature. Electron probe microanalyzer (EPMA) elemental mapping revealed that titanium segregates effectively at the alumina/solder interfaces. After aging tests at 200°C and 150°C, a double layer of Cu3Sn and Cu6Sn5 intermetallic compound was formed at the solder/copper interfaces. With an increase of aging periods, the amount of brittle compound in the joints increased and resulted in decreases in the shear strengths of the alumina/copper joints. [ABSTRACT FROM AUTHOR]

Compared to young patients with Takayasu’s arteritis (TA), little information about elderly patients with TA has been reported. Additionally, no reports were found regarding TA cases with complications of intestinal amyloidosis. This is a case report of an elderly female, who developed intestinal amyloidosis, during late-stage TA. After years of outpatient management, she developed sudden severe dyspnea with pulmonary effusion, requiring hospitalization. After this event, betamethasone was replaced by methotrexate (MTX) for the next 34 months, but it seemed ineffective. After 1.5 years, she developed intractable diarrhea, followed by increases in BUN and serum creatinine (Cr), requiring several courses of hemodialysis. Colonoscopy revealed the presence of amyloid in her intestine, although she died of complicated sepsis caused by MRSA infection. This may be the first paper describing intestinal amyloidosis in a TA patient. Additionally, her case is rare in that she lived more than 30 years after the onset and diagnosis of TA. [ABSTRACT FROM AUTHOR]