Search

A design of highly integrated polarization rotators (PRs) with double-ring resonators in add-drop filter systems is demonstrated theoretically. Based on mode-evolution theory and 3D finite-difference time-domain simulation, two vertically stacked microrings with dislocation are designed and optimized, which efficiently decreases the size of PR to a double-ring structure with a radius of <;3.5 μm for the wavelength of 1.55 μm in a silicon-on-isolator system. Numerical simulations obtain an extinction ratio (ER) of -22 dB and an insertion loss of 0.07 dB with practical material parameters. This PR combines the advantages of the periodic spectrum of ring resonators and add-drop filtering functionality. The method and result presented here can be valuable for applications in polarization-diversity circuits. [ABSTRACT FROM PUBLISHER]

A modified sequential shifting control algorithm is proposed for changing the helicopter rotor’s speed in a large variation and providing continuous output power to the rotor. Two turbo-shaft engines and two multi-speed gearboxes, coordinating with the rotor, facilitate a wide rotor speed variation and provide continuous torque to the rotor. In the process of shifting, a new control scheme is proposed to design turbo-shaft engines’ power turbine speed controller which is robust linear matrix inequality control, combined with active disturbance rejection control torque feed-forward compensation, so as to weaken engines’ torque disturbance in rotor speed variation process. In the end, some numerical simulations are carried out to verify the feasibility of the shifting algorithm, based on the integrated helicopter/engine system model which can simulate auto-flight tasks of the real system. The simulation results show that the turbo-shaft engine’s torque disturbance has little influence on engine power turbine speed in the process of torque shifting, and the rotor speed can perform large and rapid speed changes smoothly. [ABSTRACT FROM AUTHOR]

The aim of this case report and minireview was to investigate the diagnosis of and therapeutic approaches for angiocentric glioma (AG) and to summarize the clinical manifestations and the pathological and imaging characteristics of the disease. Intraoperative cortical electroencephalogram (ECoG) monitoring was performed to locate the epileptic foci in a child with AG who presented with intractable epilepsy, prior to the total resection of the tumor being performed under the microscope. The clinical features, imaging characteristics, intraoperative conditions, surgical methods and pathological results were analyzed and compared with the literature. The review revealed that to date, the clinical features of the 52 reported cases of AG (including this case) have been mainly characterized by epilepsy. High T2-weighted image (WI) and fuid-attenuated inversion recovery (FLAIR) signals may be detected with magnetic resonance imaging (MRI) scanning of the cranium; however, no enhancement signals are detected by enhanced scanning. The prognosis following surgical resection is favorable. The lesions in the present case demonstrated clear boundaries with a central cystic affection accompanied by an arachnoid cyst on the left temporal pole. Pathological examination revealed that the lesion was positive for glial fibrillary acidic protein (GFAP), S-100 protein, vimentin, epithelial membrane antigen (EMA), cluster of differentiation 99 (CD99) and D2-40. The Ki-67/MIBk-1 labeling index was ~1%. In conclusion, AG exhibits characteristic features in imaging; however, its diagnosis depends on histopathological examination. The prognosis of total surgical resection is good and intraoperative ECoG may be used to assist positioning. [ABSTRACT FROM AUTHOR]

In this paper, a flame retardant dimethyl-2-(methacryloyloxyethyl) phosphate (DMMEP) was applied to wool fabrics by the graft copolymerization technique initiated with potassium persulfate (KPS) in water media. FTIR and SEM testing were used to explore the grafting evidence on the fiber surface, the SEM results show chemical deposition on the wool fiber surface and the scales could not be seen clearly. FTIR testing exhibited IR absorption of DMMEP on the wool fiber. Thermal gravimetric analysis, differential thermal analysis (DTA), and char residue morphology SEM observation show the decomposition mode of wool fabrics and infer the possible flame retardant mechanism. The phosphorus based flame retardant DMMEP was prone to promote more nonflammble char during combustion, and increased add-on of DMMEP produced increased fabric char. With a DMMEP add-on increase from 50% to 100% on the weight of wool fabric, the treated wool fabric demonstrated high flame retardancy with an LOI above 35% which means it can not be ignited with a candle like fire, and could pass the vertical flammability test. DMMEP treatment slightly affected whiteness and moisture regain, but yielded a relatively large decrease in permeability and tensile strength, which should be explored further in later research. [ABSTRACT FROM AUTHOR]

In this paper, hemicyanine fluorescent dye, namely, trans-4-[p-(N,N-diethylamino) -styryl]-N-methyl pyridinium bromide (DEASPBr), was synthesised and applied to the dyeing of acrylic fabric using the traditional cationic dyeing procedure. The absorption spectra of the novel dye were studied under various pHs, and the dyeing properties, fluorescent reflectance, and colorimetric properties were also explored. The results showed that the adsorption mechanism of DEASPBr on acrylic fibre was in good accordance with the Langmuir type, and the dye had an obvious fluorescent effect. In addition, according to the EN-471 standard, the dye could meet the requirements of the fluorescent orange dye for high visibility warning clothing in terms of chromaticity co-ordinates and luminance factors when its concentration was limited in the appropriate range. [ABSTRACT FROM AUTHOR]

There has been growing interest in the dyeing of textiles with natural dyes. The research about the adsorption properties of natural dyes can help to understand their adsorption mechanism and to control their dyeing process. This study is concerned with the kinetics and isotherms of adsorption of lac dyes on wool, silk, and nylon fibers. It was found that the adsorption kinetics of lac dyes on the three fibers followed the pseudosecond-order kinetic model, and the adsorption rate of lac dyes was the fastest for silk and the slowest for wool. The activation energies for the adsorption process on wool, silk, and nylon were found to be 107.15, 87.85, and 45.31 kJ/mol, respectively. The adsorption of lac dyes on the three fibers followed the Langmuir mechanism, indicating that the electrostatic interactions between lac dyes and those fibers occurred. The saturation values for lac adsorption on the three fibers decreased in the order of wool > silk > nylon; the Langmuir affinity constant of lac adsorption on nylon was much higher than those on wool and silk. [ABSTRACT FROM AUTHOR]

Silk with antibacterial properties was grafted using dimethylaminoethyl methacrylate (DMAEMA) in water by the ATRP method. The structure and properties of silk-grafted-PDMAEMA (Silk-g-PDMAEMA) and quaternized grafted silk (Q-Silk-g-PDMAEMA) were investigated. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the grafting of DMAEMA and the quarternization. Differential scanning calorimetry (DSC) measurements indicate that the thermal stability of Silk-g-PDMAEMA slightly increased compared with the control silk. X-ray diffraction (XRD) curves demonstrate that the crystalline structure of Silk-g-PDMAEMA remained unchanged regardless of the DMAEMA grafting. The Q-Silk-g-PDMAEMA had good antibacterial properties when exposed to both Staphylococcus aureu and Escherichia coli, and had good washing fastness. The breaking strength, whiteness and gas permeability of Silk-g-PDMAEMA slightly decreased, which had no effect on the intrinsic properties of silk fabric. [ABSTRACT FROM AUTHOR]

Cyanobacterial toxins, especially the microcystins, are found in eutrophied waters throughout the world, and their potential to impact on human and animal health is a cause for concern. Microcystin-LR (MC-LR) is one of the common toxic microcystin congeners and occurs frequently in diverse water systems. Recent work suggested that apoptosis plays a major role in the toxic effects induced by MC-LR in hepatocytes. However, the roles of MC-LR in pancreatic beta cells have not been fully established. The aim of the present study was to assess possible in vitro effects of MC-LR on cell apoptosis in the rat insulinoma cell line, INS-1. Our results demonstrated that MC-LR promoted selectively activation of NF-κB (increasing nuclear p50/p65 translocation) and increased the mRNA and protein levels of induced nitric oxide synthase (iNOS). The chronic treatment with MC-LR stimulated nitric oxide (NO) production derived from iNOS and induced apoptosis in a dose dependent manner in INS-1 cells. Meanwhile, this effect was inhibited by the NF-κB inhibitor PDTC, which reversed the apoptosis induced by MC-LR. Our observations indicate that MC-LR induced cell apoptosis via an iNOS-dependent pathway. A well-known nuclear transcription factor, NF-κB, is activated and mediates intracellular nitric oxide synthesis. We suggest that the apoptosis induced by chronic MC-LR in vivo presents a possible cause of β-cell dysfunction, as a key environmental factor in the development of diabetes mellitus. [ABSTRACT FROM AUTHOR]

The red-emitting phosphors, Eu3+ doped nano-sized La6W012:Eu3+ and La6Mo012:Eu3+, were prepared by the Pechini method. X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and decay curves were characterized. The phosphor can be efficiently excited by near UV light and exhibits the intense red luminescence corresponding to the electric dipole transition 5D0→7F2. The lifetime values were calculated on the base of the luminescence decay curves. Meanwhile the fluorescent nanofibers could be obtained with electrospinning process by combining the phosphors into poly (vinyl alcohol) aqueous solution. [ABSTRACT FROM AUTHOR]

The fully concentrated Eu3+-based red-emitting phosphor, nanosized Eu6WO12 was prepared by the Pechini method. The phosphor was characterized by X-ray diffraction and Fourier transform IR. The structure and the average crystalline grain sizes were determined by X-ray powder diffraction and scanning electron microscopy measurements. The photoluminescence excitation and emission spectra and the decay curves were investigated. The phosphor can be efficiently excited by near-UV light and exhibits an intense red luminescence (615 nm) corresponding to the electric dipole transition 5D0 → 7F2. The nanosized Eu6WO12 was evaluated by comparing its excitation and emission spectra with those of Eu6WO12 prepared by a solid-slate reaction. The phosphor would be a promising red component for solid-state lighting devices based on InGaN or GaN light emitting diodes. An increase in rod crystalline grain sizes from 25 to 80 nm was observed with increasing annealing temperature from 600 to 800°C. The effect of grain size on the luminescence properties of Eu6WO12 nanocrystals was observed. The luminescence decays of the Eu3+ excited state was longer in smaller nanocrystalline powders. The structure symmetry and luminescence were discussed in this nanosized phosphor annealed at different temperatures. [ABSTRACT FROM AUTHOR]

The mouse is an irreplaceable model for understanding the precise genetic mechanisms of mammalian physiological pathways. Thousands of quantitative trait loci (QTLs) have been mapped onto the mouse genome during the last two decades. However, only a few genes’ underlying complex traits have been successfully identified, and rapid fine mapping of QTL genes still remains a challenge for mouse geneticists. Currently, the Collaborative Cross (CC) has proceeded to the goal of establishing more than 1,000 recombinant inbred strains for the sub-centimorgan mapping resolution of QTL loci. In this article, a novel complementary strategy, designated as population of specific chromosome substitution strains or PSCSS, is proposed for rapid fine mapping of QTLs on the substituted chromosome. One specific chromosome (Chr 1) of recipient mouse strain C57BL/6 J has been substituted by homologous counterparts from five different inbred strains (C3H/He, FVB/N, AKR, NOD/LtJ, NZW/LacJ), an outbred line Kunmin mouse in China, and 23 wild mice captured in different localities. The primary genetic studies on the structure of these wild donor chromosomes (Chr 1) show that these donor chromosomes harbor extensive genetic polymorphisms, with a high density of SNP distribution, abundant variations of STR alleles, and a high level of historical recombination accumulation. These specific chromosome substitution strains eventually form a special population that has the identical genetic background of the recipient strain and differs only in the donor chromosomes. With simple association studies, known QTLs on the donor chromosome can be rapidly mapped in high resolution without requirement of further crosses. This approach, taking advantage of the extensive genetic polymorphisms of wild resources and chromosome substitution strategy, brings a new outlook for genetic dissection of complex traits. [ABSTRACT FROM AUTHOR]

Tumor-related hemifacial spasm (HFS) has been found to be rare. During the period from October 1984 to October 2008, we treated 6,910 HFS patients using a microsurgical procedure. Of these HFS patients, 55 cases were associated with cerebellopontine angle tumors. A small craniectomy was performed in order to excise the tumor. All tumors were found to compress the root exit zone (REZ) of the facial nerve to different extents, but concomitant vascular compression of the facial nerve was observed in a majority of cases, and microvascular decompression of the facial nerve at REZ was conducted in 43 of 55 patients (78.2%) by displacing the co-compressing vasculature away from the REZ and retaining it using a Teflon pad. Intraoperative findings and postoperative pathological examinations suggested that the tumors were epidermoid cysts, meningiomas, and Schwannomas. Follow-up in 48 of 55 patients for 4–230 months after surgery showed that the clinical symptoms of HFS disappeared in 43 cases, improved in two cases, and recurred in three cases. Ten patients had sequelae associated with the operation. We concluded from this study that the majority of cases of tumor-related HFS are caused by combined tumor and vascular co-compression at the REZ, and tumor removal and microvascular decompression are required in order to relieve the symptoms. [ABSTRACT FROM AUTHOR]

Autologous nerve grafts are widely used in bridging critical gaps of peripheral nerves, but they remain associated with high morbidity of the donor site and lack of full recovery. As an alternative, we have focused on chitosan nerve conduits filled with a heparin-incorporated fibrin –fibronectin matrix serving as delivery systems for basic fibroblast growth factor (bFGF). The artificial nerve conduits were used for repairing sciatic nerve defects of 10 mm in adult rats. Three months post-operation, the conduction velocity recovery index (CVRI) and the muscle restoration rate (MRR) in animals of the experimental group were 32 ± 4.1 and 77.4 ± 7.9%, respectively, which were significantly higher than those of the PBS control group (17.8 ± 1.9 and 66.7 ± 6.5%), and similar to those of the autograft group (38.4 ± 3.9 and 81.3 ± 7.8%). These results were also consistent with the densities of regenerated axons in the three groups, which were demonstrated by histomorphological analysis. [ABSTRACT FROM AUTHOR]

Off-chip substrate routing for high-density packages is on the critical path for time to market. Compared with on-chip routers, existing commercial tools for off-chip routing have lower routability and often result in a large number of unrouted nets for manual routing. In this paper, we explain why planar routing is still required with multiple routing layers for substrate routing and then propose a flexible via-staggering technique to improve routability. In addition, we develop an efficient yet effective substrate routing algorithm, applying dynamic pushing to tackle the net ordering problem and reordering and rerouting to further reduce wire length and congestion. Compared with an industrial design tool that leaves 936 nets unrouted for nine industrial designs with a total of 6100 nets, our algorithm reduces the unrouted nets to 212, a 4.5-times net number reduction, which translates to design time reduction. [ABSTRACT FROM AUTHOR]

The principle and geometry of the microwave percutaneous coagulator system are investigated in this article; the main parts of the system are briefly introduced. A large number of experiments on porcine liver are carried out, and the temperature distribution within the liver are measured and illustrated, for cases of different injected microwave power and ablation time. In addition, the ablation areas in cases of different input microwave powers are also measured. All these results indicate the potential validity of this system on medical treatment of liver cancer of human body. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2426–2430, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23694 [ABSTRACT FROM AUTHOR]

Background: Pubertal timing in mammals is triggered by reactivation of the hypothalamic-pituitary-gonadal (HPG) axis and modulated by both genetic and environmental factors. Strain-dependent differences in vaginal opening among inbred mouse strains suggest that genetic background contribute significantly to the puberty timing, although the exact mechanism remains unknown. Methodology/Principal Findings: We performed a genome-wide scanning for linkage in reciprocal crosses between two strains, C3H/HeJ (C3H) and C57BL6/J (B6), which differed significantly in the pubertal timing. Vaginal opening (VO) was used to characterize pubertal timing in female mice, and the age at VO of all female mice (two parental strains, F1 and F2 progeny) was recorded. A genome-wide search was performed in 260 phenotypically extreme F2 mice out of 464 female progeny of the F1 intercrosses to identify quantitative trait loci (QTLs) controlling this trait. A QTL significantly associated was mapped to the DXMit166 marker (15.5 cM, LOD = 3.86, p,0.01) in the reciprocal cross population (C3HB6F2). This QTL contributed 2.1 days to the timing of VO, which accounted for 32.31% of the difference between the original strains. Further study showed that the QTL was B6-dominant and explained 10.5% of variation to this trait with a power of 99.4% at an alpha level of 0.05.The location of the significant ChrX QTL found by genome scanning was then fine-mapped to a region of ∼2.5 cM between marker DXMit68 and rs29053133 by generating and phenotyping a panel of 10 modified interval-specific congenic strains (mISCSs). Conclusions/Significance: Such findings in our study lay a foundation for positional cloning of genes regulating the timing of puberty, and also reveal the fact that chromosome X (the sex chromosome) does carry gene(s) which take part in the regulative pathway of the pubertal timing in mice. [ABSTRACT FROM AUTHOR]

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and PHBHHx-hydroxyapatite (HAP) composite scaffolds have been prepared by phase separation and subsequent sublimation of the solvent for bone tissue engineering. Scanning electron microscopy (SEM), porosity measurement, mechanical tests, and thermogravimertric analysis (TGA) are used to analyze the physical properties of the scaffolds. The biocompatibility and osteoconductivity are assessed by examining the morphology, proliferation, and differentiation of MC3T3-E1 osteoprogenitor cells seeded on the scaffolds. The PHBHHx-HAP composite scaffolds show better mechanical properties, biocompatibility, and osteoconductivity than the PHBHHx scaffolds. The results suggest that PHBHHx-HAP composite scaffolds can be employed as a promising candidate for bone reconstruction. [ABSTRACT FROM AUTHOR]

Dramatic rises in the power consumption and integration density of contemporary systems-on-chip (SoCs) have led to the need for careful attention to chip-level thermal integrity. High temperatures or uneven temperature distributions may result not only in reliability issues, but also timing failures, due to the temperature-dependent nature of chip time-to-failure and delay, respectively. To resolve these issues. high-quality, accurate thermal modeling and analysis, and thermally oriented placement optimizations, are essential prior to tapeout. This paper first presents an overview of thermal modeling and simulation methods, such as finite-difference time domain, finite element, model reduction, random walk, and Green-function based algorithms, that are appropriate for use in placement algorithms. Next, two-dimensional and three-dimensional thermal-aware placement algorithms such as matrix-synthesis, simulated annealing, partition-driven, and force directed are presented. Finally, future trends and challenges are described. [ABSTRACT FROM AUTHOR]

Background: COVID-19 is characterized by endothelial dysfunction and is presumed to have long-term cardiovascular sequelae. In this cross-sectional study, we aimed to explore the serum levels of endothelial biomarkers in patients who recovered from COVID-19 one year after hospital discharge. Methods: In this clinical follow-up study, 345 COVID-19 survivors from Huanggang, Hubei, and 119 age and gender-matched medical staff as healthy controls were enrolled. A standardized symptom questionnaire was performed, while electrocardiogram and Doppler ultrasound of lower extremities, routine blood tests, biochemical and immunological tests, serum soluble vascular cell adhesion molecule-1(VCAM-1), intercellular cell adhesion molecule-1(ICAM-1), P-selectin, and fractalkine were measured by enzyme-linked immunosorbent assays (ELISA). Results: At one year after discharge, 39% of recovers possessed post-COVID syndromes, while a few had abnormal electrocardiogram manifestations, and no deep vein thrombosis was detected in all screened survivors. There were no significant differences in circulatory inflammatory markers (leukocytes, neutrophils, lymphocytes, C-reactive protein and interleukin-6), alanine aminotransferase, estimated glomerular filtration rate, glucose, triglycerides, total cholesterol and D-dimer observed among healthy controls with previously mild or severe infected. Furthermore, serum levels of VCAM-1, ICAM-1, P-selectin, and fractalkine do not significantly differ between survivors and healthy controls. Conclusions: SARS-CoV-2 infection may not impose a higher risk of developing long-term cardiovascular events, even for those recovering from severe illness. [ABSTRACT FROM AUTHOR]

Purpose: To study the influence of ARPC4 gene silencing on human urinary bladder cancer (T24) cell proliferation, invasiveness and migration, and the mechanism(s) involved. Methods: Short interfering RNA (siRNA) ARPC4 silencing fragment was transfected into T24 cells. Transfection efficiency was measured with qRT-PCR. Cell proliferation, invasiveness and migratory potential were determined with CCK-8, Transwell invasion assay, and immunofluorescence assay, respectively. Protein expressions of ARPC4 and cofilin-1 were assayed using Western blotting. Results: Short interfering RNA (siRNA) silencing of ARPC4 gene led to the downregulation of mRNA and protein expressions of ARPC4 (t = 14.898, p < 0.05; t = 7.686, p < 0.05). It also significantly downregulated cofilin-1 protein, while inhibiting proliferative capacity, invasiveness and pseudopodiaformation capacity of T24 cells (t = 8.042, p < 0.05). Conclusion: The results obtained suggest that ARPC4 gene silencing inhibits T24 cell invasion and metastasis via a mechanism involving regulation of the Arp2/3/cofilin-1 signaling route. This provides new leads for gene therapy. [ABSTRACT FROM AUTHOR]

In order to improve flame retardance and thermal stability of wool fabric, a series of boron doped silica solswere prepared from a tetraethyl silicate inorganic precursor and applied to wool fabric as a flame retardant finish through the sol-gel process. Boric acid, zinc borate and ammonium borate were used as flame retardant additives. The effect of the boron containing flame retardant doped sol coatings on flammability, combustion behavior and thermal property of treatedwool fabricwas investigated via limited oxygen index (LOI) test, vertical burning test, thermogravimetric (TG) analysis, micro-calorimeter combustion (MCC) and smoke density test. It was found that the coatings on wool fabric acted as a heat insulation barrier, increasing the carbon residue and slowing down the spread of flame when burning, thus improving the flame retardance and thermal stability of the treated fabric. Meanwhile, the smoke density result indicated that the NH4HB4O7 doped silica sol treated fabric had good smoke suppression property. Furthermore, the result of mechanical properties showed that there was no damage on tensile strength and air permeation of treated wool fabric. [ABSTRACT FROM AUTHOR]

SENP1 (SUMO-specific protease 1) has been shown to be essential for the stability and activity of hypoxia-inducible factor 1 (HIF-1α) under hypoxia conditions. However, it is unknown how SENP1 activation and hypoxia signaling are coordinated in the cellular response to hypoxia. Here, we report the essential role of SENP1 in endothelial cells as a positive regulator of hypoxia-driven VEGF production and angiogenesis. SENP1 expression is increased in endothelial cells following exposure to hypoxia. Silencing of HIF-1α blocks SENP1 expression in cell response to hypoxia. Mutation of the hypoxia response element (HRE) on the Senp1 promoter abolishes its transactivation in response to hypoxia. Moreover, silencing of SENP1 expression decreases VEGF production and abrogates the angiogenic functions of endothelial cell. We also find that the elongated endothelial cells in embryonic brain section and vascular endothelial cells in embryonic renal glomeruli in Senp1-/- mice are markedly reduced than those in wild-type. Thus, these results show that hypoxia implies a positive feedback loop mediated by SENP1. This feedback loop is important in VEGF production, which is essential for angiogenesis in endothelial cells. [ABSTRACT FROM AUTHOR]