Comparison of online and offline tests in LED accelerated reliability tests under temperature stress

Accelerated aging tests are the main method used in the evaluation of LED reliability, and can be performed in either online or offline modes. The goal of this study is to provide the difference between the two test modes. In the experiments, the sample is attached to different heat sinks to acquire the optical parameters under different junction temperatures of LEDs. By measuring the junction temperature in the aging process (Tj1), and the junction temperature in the testing process (Tj2), we achieve consistency with an online test of Tj1 and Tj2 and a difference with an offline test of Tj1 and Tj2. Experimental results show that the degradation rate of the luminous flux rises as Tj2 increases, which yields a difference of projected life L(70%) of 8% to 13%. For color shifts over 5000 h of aging, the online test shows a larger variation of the distance from the Planckian locus, about 40% to 50% more than the normal test at an ambient temperature of 25°C.

Combined application of FBG and PZT sensors for plantar pressure monitoring at low and high speed walking

BACKGROUND

Clinical monitoring of planar pressure is vital in several pathological conditions, such as diabetes, where excess pressure might have serious repercussions on health of the patient, even to the extent of amputation.

OBJECTIVE

The main objective of this paper is to experimentally evaluate the combined application of the Fibre Bragg Grating (FBG) and the lead zirconate titanate (PZT) piezoceramic sensors for plantar pressure monitoring during walk at low and high speeds.

METHODS

For fabrication of the pressure sensors, the FBGs are embedded within layers of carbon composite material and stacked in an arc shape. From this embedding technique, average pressure sensitivity of 1.3 pm/kPa and resolution of nearly 0.8 kPa is obtained. These sensors are found to be suitable for measuring the static and the low-speed walk generated foot pressure. Simultaneously, PZT patches of size 10 × 10 × 0.3 mm were used as sensors, utilizing the d<formula>_{33}</formula> (thickness) coupling mode. A sensitivity of 7.06 mV/kPa and a pressure resolution of 0.14 kPa is obtained from these sensors, which are found to be suitable for foot pressure measurement during high speed walking and running. Both types of sensors are attached to the underside of the sole of commercially available shoes. In the experiments, a healthy male subject walks/runs over the treadmill wearing the fabricated shoes at various speeds and the peak pressure is measured using both the sensors. Commercially available low-cost hardware is used for interrogation of the two sensor types.

RESULTS

The test results clearly show the feasibility of the FBG and the PZT sensors for measurement of plantar pressure. The PZT sensors are more accurate for measurement of pressure during walking at high speeds. The FBG sensors, on the other hand, are found to be suitable for static and quasi-dynamic (slow walking) conditions. Typically, the measured pressure varied from 400 to 600 kPa below the forefoot and 100 to 1000 kPa below the heel as the walking speed varied from 1 kilometer per hour (kmph) to 7 kmph.

CONCLUSIONS

When instrumented in combination, the two sensors can enable measurements ranging from static to high speed conditions Both the sensor types are rugged, small sized and can be easily embedded in commercial shoes and enable plantar pressure measurement in a cost-effective manner. This research is expected to have application in the treatment of patients suffering from diabetes and gonarthrosis.

High-Energy Density and Superhard Nitrogen-Rich B-N Compounds

The pressure-induced transformation of diatomic nitrogen into nonmolecular polymeric phases may produce potentially useful high-energy-density materials. We combine first-principles calculations with structure searching to predict a new class of nitrogen-rich boron nitrides with a stoichiometry of B(3)N(5) that are stable or metastable relative to solid N(2) and h-BN at ambient pressure. The most stable phase at ambient pressure has a layered structure (h-B(3)N(5)) containing hexagonal B(3)N(3) layers sandwiched with intercalated freely rotating N(2) molecules. At 15 GPa, a three-dimensional C222(1) structure with single N-N bonds becomes the most stable. This pressure is much lower than that required for triple-to-single bond transformation in pure solid nitrogen (110 GPa). More importantly, C222(1)-B(3)N(5) is metastable, and can be recovered under ambient conditions. Its energy density of ∼3.44  kJ/g makes it a potential high-energy-density material. In addition, stress-strain calculations estimate a Vicker's hardness of ∼44  GPa. Structure searching reveals a new clathrate sodalitelike BN structure that is metastable under ambient conditions.

R-acetoin accumulation and dissimilation in Klebsiella pneumoniae

Klebsiella pneumoniae is a 2,3-butanediol producer, and R-acetoin is an intermediate of 2,3-butanediol production. R-acetoin accumulation and dissimilation in K. pneumoniae was studied here. A budC mutant, which has lost 2,3-butanediol dehydrogenase activity, accumulated high levels of R-acetoin in culture broth. However, after glucose was exhausted, the accumulated R-acetoin could be reused by the cells as a carbon source. Acetoin dehydrogenase enzyme system, encoded by acoABCD, was responsible for R-acetoin dissimilation. acoABCD mutants lost the ability to grow on acetoin as the sole carbon source, and the acetoin accumulated could not be dissimilated. However, in the presence of another carbon source, the acetoin accumulated in broth of acoABCD mutants was converted to 2,3-butanediol. Parameters of R-acetoin production by budC mutants were optimized in batch culture. Aerobic culture and mildly acidic conditions (pH 6–6.5) favored R-acetoin accumulation. At the optimized conditions, in fed-batch fermentation, 62.3 g/L R-acetoin was produced by budC and acoABCD double mutant in 57 h culture, with an optical purity of 98.0 %, and a substrate conversion ratio of 28.7 %.

Survival Benefits of Western and Traditional Chinese Medicine Treatment for Patients With Pancreatic Cancer

Traditional Chinese medicine (TCM) is one of the most common complementary and alternative medicines used in the treatment of patients with cancer worldwide. However, the clinical effect of TCM on patients with pancreatic cancer remains unclear. This study was aimed to explore the efficacy of TCM on selected patients with pancreatic cancer and to study the usefulness of multimodality treatment, including TCM and western medicine (WM), in pancreatic cancer.From January 2009 to October 2013, 107 patients with pancreatic cancer were included in this study. Kaplan-Meier curves were used to assess the differences in survival time. Cox regression analysis was performed to determine survival trends adjusted for clinical and demographic factors.Cox regression analysis suggested that elevated CA19-9 levels (P = 0.048), number of cycles of chemotherapy (P = 0.014), and TCM were independent prognostic factors (P < 0.001). The survival hazards ratio of TCM was 0.419 (95% confidence interval [CI], 0.261-0.671). The median overall survival (OS) was 19 months for patients with TCM treatment, while the median OS was 8 months for those without TCM treatment (P < 0.001). Patients who received multimodality treatment using TCM and WM had the best prognosis with a median OS of 19 months (P < 0.001). Patients with heat-clearing, diuresis-promoting and detoxification TCM treatment had a longer survival time (32.4 months) than those with blood-activating and stasis-dissolving (9.8 months) and tonifying qi and yang treatment (6.1 months; P = 0.008).These results indicate that TCM has an important potential value for improving the prognosis of patients with pancreatic cancer, and multimodality treatment, including TCM and WM, leads to the best prognosis. More importantly, we suggest that heat-clearing, diuresis-promoting, and detoxification TCM treatment may improve the efficacy of TCM in pancreatic cancer.

Preparation of Ge nanotube arrays from an ionic liquid for lithium ion battery anodes with improved cycling stability

Ge nanotube array anodes are prepared by template-assisted electrodeposition from an ionic liquid to obtain superior cycling performance. They show remarkable cycling ability at 0.2 C, with a very high initial discharge capacity of 1641 mA h g(-1) and a charge capacity of 1260 mA h g(-1). After 250 cycles the capacity retention is 98% relative to that at the 50th cycle.

Involvement of high mobility group box 1 in the activation of C5a-primed neutrophils induced by ANCA

C5a plays a central role in antineutrophil cytoplasmic antibody (ANCA)-mediated neutrophil recruitment and activation. A previous study showed that C5a played a crucial role in the regulation of high mobility group box 1 (HMGB1) release from human neutrophils. The current study further investigated the interaction between C5a and HMGB1 in ANCA-induced neutrophil activation. The effects of HMGB1 inhibitors on the translocation of ANCA antigens, ANCA-induced respiratory burst and degranulation of C5a-primed neutrophils were tested. We found that blocking HMGB1 decreased C5a-mediated translocation of ANCA antigens, as well as ANCA-induced respiratory burst and degranulation of C5a-primed neutrophils. Further study showed that supernatant of C5a-primed neutrophils, which contained HMGB1, also caused translocation of ANCA antigens of primary neutrophils, whereas blocking HMGB1 decreased the translocation. In conclusion, blocking HMGB1 may attenuate ANCA-induced activation of C5a-primed neutrophils. The interaction between HMGB1 and C5a might play an important role in ANCA-induced neutrophil activation.

High mobility group box 1 contributes to anti-neutrophil cytoplasmic antibody-induced neutrophils activation through receptor for advanced glycation end products (RAGE) and Toll-like receptor 4

Introduction

High mobility group box-1 (HMGB1), a typical damage-associated molecular pattern (DAMP) protein, is associated with inflammatory conditions and tissue damage. Our recent study found that circulating HMGB1 levels could reflect the disease activity of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The current study aimed to investigate whether HMGB1 participated in ANCA-induced neutrophil activation, which is one of the most important pathogenic aspects in the development of AAV.

Methods

The various effects of HMGB1 in ANCA-induced neutrophil activation were measured. Antagonists for relevant receptors and signaling molecules were employed.

Results

ANCA antigens translocation on neutrophils primed with HMGB1 was significantly higher than non-primed neutrophils. The levels of respiratory burst and degranulation increased significantly in HMGB1-primed neutrophils activated with ANCA-positive IgG, as compared with non-primed neutrophils. Furthermore, blocking Toll-like receptor 4 (TLR4) and receptor for advanced glycation end products (RAGE), rather than TLR2, resulted in a significant decrease in HMGB1-induced ANCA antigens translocation, respiratory burst and degranulation. Similar effects were also found when blocking MyD88 and NF-κB.

Conclusions

HMGB1 could prime neutrophils by increasing ANCA antigens translocation, and the primed neutrophils could be further induced by ANCA, resulting in the respiratory burst and degranulation. This process is TLR4- and RAGE-dependent through the MyD88/NF-κB pathway.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0587-4) contains supplementary material, which is available to authorized users.

N-alkylation of organo-imido substituted polyoxometalates: an efficient and stoichiometric approach for the easy post-modification of polyoxometalates

A high-yield post-functionalization protocol developed here provides an easy inclusion of the desired organic groups on a POM's highly negative surface.

Eu3+:Y2O3@CNTs—a rare earth filled carbon nanotube nanomaterial with low toxicity and good photoluminescence properties

New fluorescent nanomaterials—europium-doped yttria filled CNTs with low toxicity and good photoluminescence properties were synthesized using a supercritical method.

Direct gem-difluoromethylenation of sp3-hybridized carbon center through copper-mediated radical/radical cross-coupling for the construction of a CH2–CF2 linkage

An efficient gem-difluoromethylenation of benzyl bromides through copper-mediated direct radical/radical C–C cross-coupling has been developed for the construction of CH₂–CF₂ linkage.

One pot cascade synthesis of fused heterocycles from furan-tethered terminal alkynes and aldehydes in the presence of amines and CuBr

A novel one-pot protocol for the construction of complex heterocycles through furan tethered terminal alkynes, aldehydes, amines and CuBr upon heating has been developed, giving the cycloadducts in moderate to high yields along with moderate to good regioselectivities.

The abnormal expression level of microRNA in epithelial-mesenchymal transition of peritoneal mesothelial cells induced by high glucose

OBJECTIVE

To determine the expression level of the microRNA in the process of epithelial-mesenchymal transition (EMT) of the peritoneal mesothelial cells (PMCs) induced by high glucose.

MATERIALS AND METHODS

The PMCs were cultured using M199 medium with 10% fetal bovine serum, and the EMT was induced by D-glucose stimulation. Epithelial-mesenchymal transition was determined by changes in cell morphology and the expression levels of the EMT marker genes. Changes in cell morphology were observed by inverted microscope, and the expression levels of the EMT marker genes were determined by real-time PCR. The expression levels of the microRNA were detected by real-time PCR with microRNA-specific stem-loop structure primer.

RESULTS

The PMCs changed to fusiformis following a high-glucose medium stimulated for 48 hours, and the EMT marker genes changed significantly, such as the decrease of E-cadherin and an increase of Vimentin (p < 0.01). These results proved the EMT had been induced by high-glucose. Applying real-time PCR with microRNA-specific stem-loop structure primer, miR-193a increased notably (p < 0.01), and miR-15a and let-7e decreased (p < 0.01), while miR-16 and miR-21 had no significant changes (p > 0.05). Most importantly, the increase of miR-193a was correlated with stimulus duration.

CONCLUSIONS

MicroRNA with abnormal expression levels have a primary role in regulating the EMT of PMCs induced by high glucose.

Ionic liquid electrodeposition of Ge nanostructures on freestanding Ni-nanocone arrays for Li-ion battery

With the growing demand for portable and wearable electronic devices, it is imperative to develop high-performance Li-ion batteries with long lifetimes.

An ultra-low detection-limit optofluidic biosensor based on all glass Fabry-Perot cavity

An all glass optofludic biosensor with high quality-factor Fabry-Perot cavity (FPC) channel was reported. The all glass sandwich structure can completely eliminate the etching roughness of the channel surface, and can extend the operating wavelength to visible and ultraviolet regions compared with that of Si-based sensor. The quality-factor of the FPC channel is 875, and the system noise can be reduced to 1.2 nV by combining optical differential detection with phase lock-in detection. A detection limit of 15ng/mL for glucose solution, which corresponds to a refractive index unit of 2.0 × 10^-9, was experimentally demonstrated. The all glass FPC sensor features low cost and robust compared with surface-plasmon-resonance sensor and ring-resonator sensor.

Inhibition of autophagy strengthens celastrol-induced apoptosis in human pancreatic cancer in vitro and in vivo models

OBJECTIVES

Celastrol, a quinone methide triterpenoid, could induce apoptosis in pancreatic cancer cells. The purpose of this study is to determine whether there is protective autophagy after celastrol treatment in pancreatic cancer cells and the synergistic effects of celastrol and 3-MA in vitro and in vivo.

METHODS

The cells viability was measured using MTT assays. Degree of apoptosis and amount of autophagic vacuoles were measured by flow cytometry. Immunofluorescence was adapted to monitor the localization of autophagic protein LC3-II. Expression of LC3-II, cleaved caspase-3, Bax and bcl-2 was detected by immunoblot. Autophagosomes were observed by electron microscopy. The synergistic effect of celastrol and 3- MA in vivo was studied in the MiaPaCa-2 xenograft tumor model.

RESULTS

Celastrol increased the level of autophagy in pancreatic cancer cells. Furthermore in vitro, when inhibiting the autophagy with 3-MA, the level of celastrol-induced apoptosis elevated; after upgrading autophagy by starvation, the level of celastrol-induced apoptosis descended. 3-MA enhanced celastrol-induced apoptosis and inhibitory effect on tumor growth in vivo.

CONCLUSIONS

In pancreatic cancer, celastrol treatment increased the level of autophagy to protect cancer cells against apoptosis. Autophagy inhibitor 3-MA could improve the therapeutic effect of celastrol in vitro and in vivo.

Deaf children's use of clear visual cues in mindreading

Previous studies show that typically developing 4-year old children can understand other people's false beliefs but that deaf children of hearing families have difficulty in understanding false beliefs until the age of approximately 13. Because false beliefs are implicit mental states that are not expressed through clear visual cues in standard false belief tasks, the present study examines the hypothesis that the deaf children's developmental delay in understanding false beliefs may reflect their difficulty in understanding a spectrum of mental states that are not expressed through clear visual cues. Nine- to 13-year-old deaf children of hearing families and 4-6-year-old typically developing children completed false belief tasks and emotion recognition tasks under different cue conditions. The results indicated that after controlling for the effect of the children's language abilities, the deaf children inferred other people's false beliefs as accurately as the typically developing children when other people's false beliefs were clearly expressed through their eye-gaze direction. However, the deaf children performed worse than the typically developing children when asked to infer false beliefs with ambiguous or no eye-gaze cues. Moreover, the deaf children were capable of recognizing other people's emotions that were clearly conveyed by their facial or body expressions. The results suggest that although theory-based or simulation-based mental state understanding is typical of hearing children's theory of mind mechanism, for deaf children of hearing families, clear cue-based mental state understanding may be their specific theory of mind mechanism.