3,704 research outputs found

    Spin transport and accumulation in the persistent photoconductor Al0.3_{0.3}Ga0.7_{0.7}As

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    Electrical spin transport and accumulation have been measured in highly Si doped Al0.3Ga0.7As utilizing a lateral spin transport device. Persistent photoconductivity allows for the tuning of the effective carrier density of the channel material in situ via photodoping. Hanle effect measurements are completed at various carrier densities and the measurements yield spin lifetimes on the order of nanoseconds, an order of magnitude smaller than in bulk GaAs. These measurements illustrate that this methodology can be used to obtain a detailed description of how spin lifetimes depend on carrier density in semiconductors across the metal-insulator transition

    Whole exome and targeted deep sequencing identify genome-wide allelic loss and frequent SETDB1 mutations in malignant pleural mesotheliomas.

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    Malignant pleural mesothelioma (MPM), a rare malignancy with a poor prognosis, is mainly caused by exposure to asbestos or other organic fibers, but the underlying genetic mechanism is not fully understood. Genetic alterations and causes for multiple primary cancer development including MPM are unknown. We used whole exome sequencing to identify somatic mutations in a patient with MPM and two additional primary cancers who had no evidence of venous, arterial, lymphovascular, or perineural invasion indicating dissemination of a primary lung cancer to the pleura. We found that the MPM had R282W, a key TP53 mutation, and genome-wide allelic loss or loss of heterozygosity, a distinct genomic alteration not previously described in MPM. We identified frequent inactivating SETDB1 mutations in this patient and in 68 additional MPM patients (mutation frequency: 10%, 7/69) by targeted deep sequencing. Our observations suggest the possibility of a new genetic mechanism in the development of either MPM or multiple primary cancers. The frequent SETDB1 inactivating mutations suggest there could be new diagnostic or therapeutic options for MPM

    Copy Number Variation of Age-Related Macular Degeneration Relevant Genes in the Korean Population

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    PURPOSE: Studies that analyzed single nucleotide polymorphisms (SNP) in various genes have shown that genetic factors are strongly associated with age-related macular degeneration (AMD) susceptibility. Copy number variation (CNV) may be an additional type of genetic variation that contributes to AMD pathogenesis. This study investigated CNV in 4 AMD-relevant genes in Korean AMD patients and control subjects. METHODS: Four CNV candidate regions located in AMD-relevant genes (VEGFA, ARMS2/HTRA1, CFH and VLDLR), were selected based on the outcomes of our previous study which elucidated common CNVs in the Asian populations. Real-time PCR based TaqMan Copy Number Assays were performed on CNV candidates in 273 AMD patients and 257 control subjects. RESULTS: The predicted copy number (PCN, 0, 1, 2 or 3+) of each region was called using the CopyCaller program. All candidate genes except ARMS2/HTRA1 showed CNV in at least one individual, in which losses of VEGFA and VLDLR represent novel findings in the Asian population. When the frequencies of PCN were compared, only the gain in VLDLR showed significant differences between AMD patients and control subjects (p = 0.025). Comparisons of the raw copy values (RCV) revealed that 3 of 4 candidate genes showed significant differences (2.03 vs. 1.92 for VEGFA, p<0.01; 2.01 vs. 1.97 for CFH, p<0.01; 1.97 vs. 2.01, p<0.01 for ARMS2/HTRA1). CONCLUSION: CNVs located in AMD-relevant genes may be associated with AMD susceptibility. Further investigations encompassing larger patient cohorts are needed to elucidate the role of CNV in AMD pathogenesis

    The Efficacy and Safety of Ablative Fractional Resurfacing Using a 2,940-Nm Er:YAG Laser for Traumatic Scars in the Early Posttraumatic Period

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    BackgroundSkin injuries, such as lacerations due to trauma, are relatively common, and patients are very concerned about the resulting scars. Recently, the use of ablative and non-ablative lasers based on the fractional approach has been used to treat scars. In this study, the authors demonstrated the efficacy and safety of ablative fractional resurfacing (AFR) for traumatic scars using a 2,940-nm erbium: yttrium-aluminum-garnet (Er:YAG) laser for traumatic scars after primary repair during the early posttraumatic period.MethodsTwelve patients with fifteen scars were enrolled. All had a history of facial laceration and primary repair by suturing on the day of trauma. Laser therapy was initiated at least 4 weeks after the primary repair. Each patient was treated four times at 1-month intervals with a fractional ablative 2,940-nm Er:YAG laser using the same parameters. Post-treatment evaluations were performed 1 month after the fourth treatment session.ResultsAll 12 patients completed the study. After ablative fractional laser treatment, all treated portions of the scars showed improvements, as demonstrated by the Vancouver Scar Scale and the overall cosmetic scale as evaluated by 10 independent physicians, 10 independent non-physicians, and the patients themselves.ConclusionsThis study shows that ablative fractional Er:YAG laser treatment of scars reduces scars fairly according to both objective results and patient satisfaction rates. The authors suggest that early scar treatment using AFR can be one adjuvant scar management method for improving the quality of life of patients with traumatic scars

    Effects of Polymeric Additives on the Crystallization and Release Behavior of Amorphous Ibuprofen

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    Some polymeric additives were studied to understand their effects on the amorphous phase of ibuprofen (IBU), used as a poorly water soluble pharmaceutical model compound. The amorphous IBU in bulk, as well as in nanopores (diameter ~24 nm) of anodic aluminum oxide, was examined with the addition of poly(acrylic acid), poly(N-vinyl pyrrolidone), or poly(4-vinylphenol). Results of bulk crystallization showed that they were effective in limiting the crystal growth, while the nucleation of the crystalline phase in contact with water was nearly instantaneous in all cases. Poly(N-vinyl pyrrolidone), the most effective additive, was in specific interaction with IBU, as revealed by IR spectroscopy. The addition of the polymers was combined with the nanoscopic confinement to further stabilize the amorphous phase. Still, the IBU with addition of polymeric additives showed sustained release behavior. The current study suggested that the inhibition of the crystal nucleation was probably the most important factor to stabilize the amorphous phase and fully harness its high solubility
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