Under Xe ion irradiation, the microstructural evolution of a nickel based alloy, Hastelloy N (US N10003), was studied. The intrinsic dislocations are decorated with irradiation induced interstitial ...loops and/or clusters. Moreover, the intrinsic dislocations density reduces as the irradiation damage increases. The disappearance of the intrinsic dislocations is ascribed to the dislocations climb to the free surface by the absorption of interstitials under the ion irradiation. Moreover, the in situ annealing experiment reveals that the small interstitial loops and/or clusters induced by the ion irradiation are stable below 600°C.
The magnetic topological materials have attracted much attention recently for their potential realization of various novel quantum states. However, the onset of magnetization in these materials ...usually occurs at low temperatures, impeding further applications. Here, by means of high pressure, we have significantly increased the magnetic transition temperature in an antiferromagnetic axion insulator candidate EuIn2As2 . Both crystal and magnetic structures remain the same with pressure up to 17 GPa. The Néel temperature can be monotonously increased from 16 K (ambient pressure) to 65 K (14.7 GPa). This is mainly attributed to the enhancement of intralayer ferromagnetic exchange coupling by pressure. With increasing pressure up to 17 GPa, a crystalline-to-amorphous phase transition occurs, which impedes further enhancement of the Néel temperature. Our results show that high pressure is an effective pathway to greatly enhance the magnetic transition temperature in topological materials. It is helpful for the realization of novel quantum states at elevated temperatures.
Bactrocera zonata (Saunders) is one of the most harmful species of Tephritidae. It causes extensive damage in Asia and threatens many countries located along or near the Mediterranean Sea. The ...climate mapping program, CLIMEX 3.0, and the GIS software, ArcGIS 9.3, were used to model the current and future potential geographical distribution of B. zonata. The model predicts that, under current climatic conditions, B. zonata will be able to establish itself throughout much of the tropics and subtropics, including some parts of the USA, southern China, southeastern Australia and northern New Zealand. Climate change scenarios for the 2070s indicate that the potential distribution of B. zonata will expand poleward into areas which are currently too cold. The main factors limiting the pest's range expansion are cold, hot and dry stress. The model's predictions of the numbers of generations produced annually by B. zonata were consistent with values previously recorded for the pest's occurrence in Egypt. The ROC curve and the AUC (an AUC of 0.912) were obtained to evaluate the performance of the CLIMEX model in this study. The analysis of this information indicated a high degree of accuracy for the CLIMEX model. The significant increases in the potential distribution of B. zonata projected under the climate change scenarios considered in this study suggest that biosecurity authorities should consider the effects of climate change when undertaking pest risk assessments. To prevent the introduction and spread of B. zonata, enhanced quarantine and monitoring measures should be implemented in areas that are projected to be suitable for the establishment of the pest under current and future climatic conditions.
A new algorithm (FYVOLC) for the automated detection of volcanic hot spots using data obtained from China's new-generation satellite FY-4A is developed and tested. FYVOLC improves the detection ...ability of the Volcanic Anomaly SofTware (VAST) algorithm by incorporating a Normalized Brightness Temperature Difference Index (NBTDI) to reduce the influence of 'cold' cloud. In addition, FYVOLC introduces a mid-infrared brightness temperature criterion to identify volcanic hot spots by making calculations based on the image itself without artificially determining any parameters. To test the volcanic hot-spot detection performance of FYVOLC, FY-4A Advanced Geostationary Radiation Imager data were used for eruptions from four volcanoes: Mayon Volcano in the Philippines (25-26 January 2018), and Bromo (1-2 September 2018), Lawu (3-4 September 2018), and Soputan volcanoes (3-4 October 2018) in Indonesia. A total of 147 images of the above four volcanoes were used, and the results obtained using the FYVOLC algorithm were compared with those from three existing volcanic hot-spot detection algorithms: the simplified contextual, VAST, and HOTSAT algorithms. It is shown that the simplified contextual and VAST algorithms are prone to generating false alerts (with a maximum false alert rate of up to 41% and 48%, respectively), whereas the simplified contextual and HOTSAT algorithms are prone to missing hot-spot pixels (with a maximum miss rate of up to 71% and 54%, respectively). The FYVOLC algorithm has the best detection accuracy owing to the adopted NBTDI and image-based mid-infrared brightness temperature criterion. The maximum false alert rate of FYVOLC is 12%, and the maximum miss rate is 11%. By analysing the thermal anomaly time-series of the 147 images, it was found that the detection results of FYVOLC are basically consistent with the actual hot spots, except for some images that were strongly affected by cloud cover. This study is the first to realize the automated detection of volcanic hot spots and monitor temporally dynamic thermal phenomena based on FY-4A satellite data. The results have significance for the continuing development of global volcanic early-warning systems and for the dynamic monitoring of volcanoes after eruptions.
We demonstrate the first proof of principle differential phase shift (DPS) quantum key distribution (QKD) using narrow-band heralded single photons with amplitude-phase modulations. In the 3-pulse ...case, we obtain a quantum bit error rate (QBER) as low as 3.06% which meets the unconditional security requirement. As we increase the pulse number up to 15, the key creation efficiency approaches 93.4%, but with a cost of increasing the QBER. Our result suggests that narrow-band single photons maybe a promising source for the DPS-QKD protocol.
Hepatitis B virus (HBV) infection and its sequelae remain a major health problem for Taiwan. The national hepatitis B (HB) vaccination programme was first launched in 1984 to combat the spread of ...this infection. This study examined the status of HBV infection amongst students at a Taiwanese university in 2005, 18 years after the implementation of a nation‐wide mass HB vaccination programme. In 2005, 5875 new university entrants, who were born during the period 1 July 1976 to 30 June 1988, were subdivided into one of 12 one‐year‐interval birth‐year cohorts. Each student was individually tested for serum hepatitis B surface antigen (HBsAg), Antibody to hepatitis B surface antigen (anti‐HBs) and antibody to hepatitis B core antigen (anti‐HBc) status. We observed a declining trend of past exposure to HB infection from 48.7% (1976 birth‐year cohort) to 5.2% (1987 birth‐year cohort). The prevalence of chronic HB infection also declined from 14.5% (1976 birth‐year cohort) to 1.9% (1987 birth‐year cohort). The prevalence of persistent HB immunity through (earlier) active vaccination declined from 72% (1984 birth‐year cohort) to 41.6% (1987 birth‐year cohort). The prevalence of HB infection‐naïve individuals increased from 18.2% (1984 birth‐year cohort) to 53.1% (1987 birth‐year cohort). This study demonstrates that as the implementation of the mass HB vaccination programme in 1984, the incidence of HB infection in Taiwan has declined, although a ‘waning‐off’ effect of serum anti‐HBs to low or undetectable levels, which may not provide protection, amongst this student population has arisen, 18 years following the implementation of the nation‐wide HB vaccination programme. Such a situation may mean that these individuals may not be effectively protected against future HB infection. A booster dose of HB vaccine, given 18 years following HB vaccination, perhaps even earlier, should be considered.
Age-related macular degeneration (AMD) is a leading cause of visual impairment and irreversible blindness in most developed countries, affecting about 50 million elderly people worldwide. Retinal ...pigment epithelial (RPE) cell degeneration is the pathophysiological cause of AMD, leading to geographic atrophy and choroidal neovascularization. We and others have previously identified several polymorphisms on chromosome 10q26 (HTRA1 rs11200638 as well as LOC387715 rs10490924 and c.372_815del443ins54) associated with AMD. In this study, we confirmed the association of our previously identified HTRA1 insertion–deletion (indel) variant (c.34delCinsTCCT) in 195 exudative AMD patients and 390 controls from the Hong Kong Chinese cohort with additional 168 patients and 210 controls from the Chengdu Chinese cohort and followed by studying its biological functions in RPE cells. Genetic analysis verified the higher prevalence of c.34delCinsTCCT allele in control subjects (8.0%) than in AMD patients (1.9%; P=7.87 × 10−5, odds ratio=0.229). This protective effect was validated as the haplotype of the c.34delCinsTCCT allele existed independent of the risk haplotype (P=1.17 × 10−5). In vitro studies showed that recombinant HTRA1 c.34delCinsTCCT variant protein was more localized in the endoplasmic reticulum of RPE cells compared with the wild-type protein, and its secretion was delayed. Moreover, ARPE-19 cells expressing HTRA1 c.34delCinsTCCT variant had higher cell viability, lower cell apoptosis and were less responsive to anoikis, supporting its protective role. We revealed a protective AMD-associated HTRA1 variant in Chinese populations and the biological role of HTRA1 in RPE cell degeneration, indicating its involvement in AMD pathogenesis.
Abstract
NAD(P)H-dependent enzymes are ubiquitous in metabolism and cellular processes and are also of great interest for pharmaceutical and industrial applications. Here, we present a ...structure-guided enzyme engineering strategy for improving catalytic properties of NAD(P)H-dependent enzymes toward native or native-like reactions using mutations to the enzyme's adenine-binding pocket, distal to the site of catalysis. Screening single-site saturation mutagenesis libraries identified mutations that increased catalytic efficiency up to 10-fold in 7 out of 10 enzymes. The enzymes improved in this study represent three different cofactor-binding folds (Rossmann, DHQS-like, and FAD/NAD binding) and utilize both NADH and NADPH. Structural and biochemical analyses show that the improved activities are accompanied by minimal changes in other properties (cooperativity, thermostability, pH optimum, uncoupling), and initial tests on two enzymes (ScADH6 and EcFucO) show improved functionality in Escherichia coli.
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