Anisotropic optical response of nanocrystalline v2O5 thin films and effects of oxygen vacancy formation

We report a high sensitivity to oxygen vacancy formation as well as the temperature dependence of anisotropic optical properties of a nanocrystalline V2O5 thin film. Spectroscopic ellipsometry data show that the film has a uniaxial optical anisotropy due to a highly ordered nanocrystalline layer structure. The anisotropic optical properties of the film begin to change at 400 K in a high vacuum and can be linked to the changes in the electronic structure of the film upon reduction. An increase in the refractive indices, anisotropic changes of the optical conductivities, and a decrease in film thickness are observed after vacuum heating and are recovered to original values by heating in air up to 480 K. The experimental results are supported by the previous theoretical studies on the stability of reduced V2O5 surface through the formation of oxygen vacancies. We discuss the formation of oxygen vacancies, vacancy-induced structural relaxations, and changes in the electronic structure of V2O5 in conjunction with the experimental results.1441sciescopu

Gas Metal Arc Welding with Undermatched Filler Wire for hot-press-formed steel of 2.0 GPa strength: Influence of filler wire strength and bead geometry

Commercial welding filler wires have less strength than hot-press-forming (HPF) steels. As the 2.0 GPa-HPF steel sheets have been released, their lap welding characteristics were investigated using gas metal arc welding in this study. The base metal was 1.1 mm-thick 2.0 GPa-HPF steel sheets, and three filler metal wires considered in this study (W540, W920, and W980) had tensile strengths of 540, 920, and 980 MPa, respectively. Gas metal arc welding was performed under a controlled short-circuit mode, and the wire feed speed (WFS) was selected as a process parameter. Tensile-shear test and microscopy were performed to evaluate the joint strength and metallurgical characteristics. The joint strength increased when WFS increased. When the WFS was 6 m/min or higher and high strength filler wires were applied to it, a heat affected zone (HAZ) fracture was observed in the tensile-shear test, with a tensile strength of approximately 1150 MPa. The fracture location was the boundary of the sub-critical HAZ (comprising tempered martensite) and intercritical HAZ (comprising polygonal ferrite and martensite). The weld metal (WM) hardness for W540 welds was 270 HV, and that for W920 and W980 was 414–419 HV, while the joint strength for the WM fracture was proportional to the throat thickness. For low WFS (when the heat input per unit length and welding current were low), high strength filler metals enhanced the joint strength, while high welding currents and deep penetration welding modes were recommended for W540. This study provided the filler wire and bead geometry design for the lap welds of 2.0 GPa HPF steel sheets

A Novel Multicasting Scheme over Wireless LAN Systems by Using Relay

Abstract. We propose a novel multicast scheme that can provide qualityof-service (QoS) to multicast service over IEEE 802.11 wireless LANs by utilizing medium access control (MAC) layer relay. It is well known that IEEE 802.11 provides a physical layer multi-rate capability in response to different channel conditions, and hence packets may be delivered at a higher data rate through a relay node than through the direct link if the direct link has low quality and low data rate. We develop the distributed relay node selection algorithm and the relay channel selection algorithm. The effectiveness of proposed scheme is examined by numerical method and simulation. Simulations show that the proposed relayed multicast significantly improves throughput and delay performance

Geographic variation and factors associated with rates of knee arthroplasty in Korea-a population based ecological study

Background The recent increase in knee arthroplasty (KA) use in Korea is among the highest in the world. The rapid increase in KA use suggests that the KA use in Korea could have been affected by medically unjustifiable factors. This study aimed to examine the geographic variation in the rate of KA and its associated factors in Korea. Methods We used the data from the National Health Insurance in Korea in 2013, from which a total of 67,086 claims for KA were obtained. We calculated the age-sex-standardized KA rates of the entire population and the crude rates of the age groups 0–64 and 65 and over in 251 districts. We assessed the geographic variation of the KA rates and examined the associated factors with a multivariate linear regression with the KA rate as a dependent variable. Results The overall rate of KA in Korea was 132.7 per 100,000 persons. The rates of KA showed a four-fold variation. The deprivation index score and the number of beds in the small to medium sized hospitals showed a positive association with the rates of KA while the number of orthopedic surgeons showed a negative association. Conclusions Korea has been experiencing a rapid increase in the use of KA for the last decade or so, which was most prominent among the elderly population aged 65 and older. Our results suggest that the higher rate of KA is strongly related to a higher supply of beds and the socioeconomically deprived conditions. Considering that the decision concerning KA has room for discretion and also affects a considerable portion of health care expenditures, the use of KA should be thoroughly monitored with more emphasis on standardization in the decision making process and preventive measures that can lessen the need for KA.This work was supported by the National Health Insurance Service in Korea. The funding source had no role in study design, data analysis, or data interpretation

Peptidyl arginine deiminase type IV (PADI4) haplotypes interact with shared epitope regardless of anti-cyclic citrullinated peptide antibody or erosive joint status in rheumatoid arthritis: a case control study

Introduction: Anti-cyclic citrullinated peptide autoantibodies (anti-CCP) are the most specific serologic marker for rheumatoid arthritis (RA). Genetic polymorphisms in a citrullinating (or deiminating) enzyme, peptidyl arginine deiminase type IV (PADI4) have been reproducibly associated with RA susceptibility in several populations. We investigated whether PADI4 polymorphisms contribute to anti-CCP-negative as well as -positive RA, whether they influence disease severity (erosive joint status), and whether they interact with two major risk factors for RA, Human Leukocyte Antigen-DRB1 (HLA-DRB1) shared epitope (SE) alleles and smoking, depending on anti-CCP and erosive joint status.Methods: All 2,317 unrelated Korean subjects including 1,313 patients with RA and 1,004 unaffected controls were genotyped for three nonsynonymous (padi4_89, padi4_90, and padi4_92) and one synonymous (padi4_104) singlenucleotide polymorphisms (SNPs) in PADI4 and for HLA-DRB1 by direct DNA sequence analysis. Odds ratios (OR) were calculated by multivariate logistic regression. Interaction was evaluated by attributable proportions (AP), with 95% confidence intervals (CI).Results: A functional haplotype of the three fully correlated nonsynonymous SNPs in PADI4 was significantly associated with susceptibility to not only anti-CCP-positive (adjusted OR 1.73, 95% CI 1.34 to 2.23) but also -negative RA (adjusted OR 1.75, 95% CI 1.15 to 2.68). A strong association with both non-erosive (adjusted OR 1.62, 95% CI 1.29 to 2.05) and erosive RA (adjusted OR 1.62, 95% CI 1.14 to 2.31) was observed for PADI4 haplotype. Gene-gene interactions between the homozygous RA-risk PADI4 haplotype and SE alleles were significant in both anti-CCP-positive (AP 0.45, 95% CI 0.20 to 0.71) and -negative RA (AP 0.61, 95% CI 0.29 to 0.92). Theses interactions were also observed for both non-erosive (AP 0.48, 95% CI 0.25 to 0.72) and erosive RA (AP 0.46, 95% CI 0.14 to 0.78). In contrast, no interaction was observed between smoking and PADI4 polymorphisms.Conclusions: A haplotype of nonsynonymous SNPs in PADI4 contributes to development of RA regardless of anti-CCP or erosive joint status. The homozygous PADI4 haplotype contri bution is affected by gene-gene interactions with HLADRB1 SE alleles.We are grateful to many research workers for assistance with sample preparation, data collection, and technical study. Dr. Bang's work was supported by a grant from the Korea Healthcare Technology R&D Project (A090706). Dr. Bae's work was supported by a grant from the Korea Healthcare Technology R&D Project (A084794 and A010252). Dr. Kang's work was supported by a grant from the Research Program for New Drug Target Discovery (M10748000231-08N4800-23110)

Isolation and Profiling of Circulating Tumorâ Associated Exosomes Using Extracellular Vesicular Lipidâ Protein Binding Affinity Based Microfluidic Device

Extracellular vesicles (EVs) are emerging as a potential diagnostic test for cancer. Owing to the recent advances in microfluidics, onâ chip EV isolation is showing promise with respect to improved recovery rates, smaller necessary sample volumes, and shorter processing times than ultracentrifugation. Immunoaffinityâ based microfluidic EV isolation using antiâ CD63 is widely used; however, antiâ CD63 is not specific to cancerâ EVs, and some cancers secrete EVs with low expression of CD63. Alternatively, phosphatidylserine (PS), usually expressed in the inner leaflet of the lipid bilayer of the cells, is shown to be expressed on the outer surface of cancerâ associated EVs. A new exosome isolation microfluidic device (newExoChip), conjugated with a PSâ specific protein, to isolate cancerâ associated exosomes from plasma, is presented. The device achieves 90% capture efficiency for cancer cell exosomes compared to 38% for healthy exosomes and isolates 35% more A549â derived exosomes than an antiâ CD63â conjugated device. Immobilized exosomes are then easily released using Ca2+ chelation. The recovered exosomes from clinical samples are characterized by electron microscopy and westernâ blot analysis, revealing exosomal shapes and exosomal protein expressions. The newExoChip facilitates the isolation of a specific subset of exosomes, allowing the exploration of the undiscovered roles of exosomes in cancer progression and metastasis.Onâ chip exosome isolation using immunoaffinity capture improves recovery from small sample volumes compared to ultracentrifugation. However, tetraspanins are not specific to cancer exosomes and some cancers secrete exosomes with low expression of tetraspanins. Here, a microfluidicâ device conjugated with proteins against phosphatidylserine (PS), shown to be expressed on the outer surface of cancerâ associated exosome, is used to isolate cancerâ associated exosomes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152534/1/smll201903600-sup-0001-SuppMat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152534/2/smll201903600_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152534/3/smll201903600.pd