The Defects Genome of Janus Transition Metal Dichalcogenides.

2D Janus Transition Metal Dichalcogenides (TMDs) have attracted much interest due to their exciting quantum properties arising from their unique two-faced structure, broken-mirror symmetry, and consequent colossal polarization field within the monolayer. While efforts are made to achieve high-quality Janus monolayers, the existing methods rely on highly energetic processes that introduce unwanted grain-boundary and point defects with still unexplored effects on the material's structural and excitonic properties Through high-resolution scanning transmission electron microscopy (HRSTEM), density functional theory (DFT), and optical spectroscopy measurements; this work introduces the most encountered and energetically stable point defects. It establishes their impact on the material's optical properties. HRSTEM studies show that the most energetically stable point defects are single (VS and VSe) and double chalcogen vacancy (VS -VSe), interstitial defects (Mi), and metal impurities (MW) and establish their structural characteristics. DFT further establishes their formation energies and related localized bands within the forbidden band. Cryogenic excitonic studies on h-BN-encapsulated Janus monolayers offer a clear correlation between these structural defects and observed emission features, which closely align with the results of the theory. The overall results introduce the defect genome of Janus TMDs as an essential guideline for assessing their structural quality and device properties.

A substitutional quantum defect in WS2 discovered by high-throughput computational screening and fabricated by site-selective STM manipulation.

Point defects in two-dimensional materials are of key interest for quantum information science. However, the parameter space of possible defects is immense, making the identification of high-performance quantum defects very challenging. Here, we perform high-throughput (HT) first-principles computational screening to search for promising quantum defects within WS2, which present localized levels in the band gap that can lead to bright optical transitions in the visible or telecom regime. Our computed database spans more than 700 charged defects formed through substitution on the tungsten or sulfur site. We found that sulfur substitutions enable the most promising quantum defects. We computationally identify the neutral cobalt substitution to sulfur (Co S 0 ) and fabricate it with scanning tunneling microscopy (STM). The Co S 0 electronic structure measured by STM agrees with first principles and showcases an attractive quantum defect. Our work shows how HT computational screening and nanoscale synthesis routes can be combined to design promising quantum defects.

Rapid and sensitive dilute-and-shoot analysis using LC-MS-MS for identification of multi-class psychoactive substances in human urine.

The emergence of new psychoactive substances currently exceeding a thousand is rapidly changing substance prevalence patterns and straining the methods used for detection, most of which are suitable only for a single class of substances. This study presents a rapid and facile dilute-and-shoot system operated in conjunction with an optimized liquid chromatographic separation system for the high-sensitivity detection of substances across a range of substance classes with 3 isotopes used only. The proposed method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) is able to identify 68 substance and their metabolites in urine samples as small as 50 µL. Optimal chromatographic conditions including 95% water/methanol ratio with 0.1% added formic acid and a prolonged LC gradient run-time (15 min) improved the peak shape of polar compounds and enhanced signal strength by 5%. Under 4-fold dilution, all analytes were within 80-120% of tolerance response levels, indicating that the matrix effect was insignificant. In experiments, the limit of detection (LOD) ranged from 0.05 to 0.5 ng mL-1, while the coefficient of determination (R2) was > 0.9950. The retention time shift of each peak remained at < 2% with an inter-day relative standard deviation (RSD) of 0.9-14.9% and intra-day RSD of 1.1%- 13.8%. The rapid dilute-and-shoot presents a high-sensitivity, significant stability, robustness and reproducibility without serious interference. To demonstrate the effectiveness of the system, 532 urine samples were collected from suspected drug abusers, and the proposed method was used for rapid analysis. Of these samples, 79.5% contained between one and twelve analytes, and 12.4% tested positive for new psychoactive substances, mostly derivatives of amphetamine and synthetic cathinones. The study presents a high-sensitivity analytic system that is capable of detecting substances from multiple classes and can be used for effective monitoring of substance prevalence in urine.

Effect of stimuli type on affective memory of patients with different severities of cognitive impairment.

OBJECTIVES: To understand the differences in affective memory performance under different degrees of cognitive impairment, this study recruited older people with different degrees of cognitive impairment, to perform emotion recognition memory tasks. METHODS: Fifty-four elderly participants aged (65-85 years) were recruited. Of these, 18 had mild cognitive impairment, 18 had a mild form of Alzheimer's disease, and the remaining 18 were healthy. Factors such as the different emotional valences (positive, neutral, or negative) and stimulus types (pictures, words, or sounds) were manipulated to explore their influences on the emotion recognition memory of people with different degrees of cognitive impairment. RESULTS: The results showed that people's performance to positive stimuli worsened as their degree of cognitive impairment increased. All participants had difficulty processing memory of affective sound stimuli compared to the other two stimulus types. CONCLUSIONS: The results explain the decline in the cognitive ability process, in affective memory performance, of people with different degrees of cognitive impairment. This abnormal decline on affective memory performance could be an early diagnostic indicator of Alzheimer's disease. The results can hopefully be used as a reference for subsequent research on cognition-related diseases and age-related decline, especially regarding affective memory.

Will Natural Media Make Online Physicians More Trustworthy? The Effect of Media Naturalness on Patients' Intention to Use HIT.

Although previous studies have recognized the important role of patients' trust in promoting their intention to use health information technologies (HIT), most of those studies were under the "risk-benefit" theoretical framework. To deepen the understanding of patients' online consultation decisions, this paper develops a dual-path model investigating how patients develop trust beliefs toward online physicians from the perspective of communication. Drawing on media naturalness theory, we propose that HIT media naturalness will improve patients' perception of communication effort from online physicians and decrease communication ambiguity between patients and online physicians. This improved communication will further strengthen patients' trust in online physicians and promote their intention to use HIT. Based on a two-wave time-lagged survey from 361 participants, the empirical results demonstrated that the relationship between HIT media naturalness and patients' intention to use HIT is individually and serially mediated by two chains, including (1) perceived communication effort and patients' trust and (2) perceived communication ambiguity and patients' trust. We thus contribute to the related literature and provide practical implications.

Phosphorylated α-synuclein in diluted human serum as a biomarker for Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders, which characterized by increased pathological marker protein, α-synuclein (α-syn) and phosphorylated-Ser129-α-syn in the extracellular fluids. Current methods of measuring the p-Ser129-α-syn concentration in cerebrospinal fluid for PD are based on ELISA method, however, the amount of area under the curve (AUC) to predict PD is around 0.7-0.8. Higher confidence level of AUC in p-Ser129-α-syn quantification for the early diagnosis of PD would be essential. METHODS: Detection of p-Ser129-α-syn in diluted human serum for diagnosis of PD was investigated by a modified paired surface plasma wave biosensor (PSPWB) using a quarter wave plate for better detection performance. The method combining an immunoassay and non-labeled technique measures the p-Ser129-α-syn level with high sensitivity and specificity. Ten patients with PD at early stage (Hohn & Yahr stage I and II) and 11 age-matched healthy control participants were recruited for measurement of serum p-Ser129-α-syn. RESULTS: AUC of the p-Ser129-α-syn in diluted human serum was 0.92 and it shows that p-Ser129-α-syn in diluted human serum could be used as a sensitive biomarker for the diagnosis of PD in clinics. Results clearly show that the measured p-Ser129-α-syn concentration in diluted human serum displays a statistical significance between health control subjects and PD patients. CONCLUSIONS: P-Ser129-α-syn has low abundance in human serum, high detection sensitivity and specificity are critical to the success of the diagnosis of PD in clinics. In this study, a modified PSPWB was developed that the limit of detection at 1 ng/mL for p-Ser129-α-syn (standard) spiked into diluted human serum of a healthy control was performed. This result shows that the modified PSPWB can be used as a platform for detecting p-Ser129-α-syn in diluted human serum as a potential biomarker for PD.

A proposed approach to confirm heroin administration - Regional differences in heroin purity is a major factor.

In forensic toxicology, a marker of street heroin use is urgent especially in the absence of urinary 6-monoacetylmorphine. ATM4G, the Glucuronide of Acetylated product of Thebaine compound 4 Metabolite (ATM4), arising from byproducts of street heroin synthesis has been considered as a useful marker in some European studies. However, whether ATM4G is a universal marker particularly in Southeast Asia due to 'street' heroin with high purity, it's still unclear. To investigate putative markers for different regions, ATM4G and other metabolites including the Acetylated product of Thebaine compound 3 Metabolite (ATM3) and thebaol, also originated from thebaine were detected in 552 urine samples from heroin users in Taiwan. Results were compared with that from samples collected in the UK and Germany. Only a sulfo-conjugate of ATM4, ATM4S, was detected in 28 Taiwanese users using a sensitive MS3 method whilst out of 351 samples from the UK and Germany, ATM4G was present in 91. Thebaol-glucuronide was first time detected in 118. No markers were detected in urine following herbal medicine use or poppy seed ingestion. The presence of ATM4S/ATM4G might be affected by ethnicities and heroin supplied in regions. Thebaol-glucuronide is another putative marker with ATM4G and ATM4S for street heroin use.

Role of stimulus types and valence on the affective memory performance of adults with anxiety.

Previous studies have found that the emotion of anxiety in adults is easily influence by negative stimuli However, few studies have explored the effect of stimulus types on working memory performance and cognitive processing of adults with anxiety. This study aimed to explore the effects of anxiety on affective working memory and the role of stimulus types and valences on affective working memory performance. Forty adults were recruited for the experiment and were divided into two groups according to their anxiety levels. The valence and type of stimulus were manipulated in a memory recognition experiment. The results indicated that individuals with anxiety performed poorer when subjected to positive stimuli than for neutral and negative stimuli, whereas healthy adults exhibited the opposite. Furthermore, participants outperformed on affective pictures than affective words, but the effect size of the words was larger than that of the pictures for the difference between the valence and anxiety groups. This study highlights the differences in affective working performance across stimulus types and valences between healthy adults and adults with anxiety. The findings clarified the effect of positive valence and affective words on the affective working memory processing mechanism in adults with anxiety.

How Does Leader Empowering Behavior Promote Employee Knowledge Sharing? The Perspective of Self-Determination Theory.

Although scholars have recognized the important role of leader empowering behavior in promoting employee knowledge sharing, investigations on the potential underlying mechanism are still limited. To enrich studies revealing the possible underlying paths, drawing on self-determination theory, this paper proposes a moderated mediation model. We propose that employee self-determination plays a mediating role and employee proactivity moderates the mediating effect. We test our hypotheses based on data collected from 230 employees across a three-wave study. The empirical results demonstrate that leader empowering behavior promotes employee knowledge sharing by enhancing employee self-determination. Employees' proactive personality moderates the indirect effect such that the indirect effect is stronger when employees have high levels of proactive personality. This paper thus contributes to the related literature and reveals practical implications.

Memory Performance of People with Different Dementia Severity for Different Semantic Hierarchies.

BACKGROUND: Memory disorder is a significant symptom during early-stage Alzheimer's disease (AD). Changes in semantic memory are frequently seen in terms of forgetting names, loss of word meanings, and difficulties in linguistic expression. Significant semantic degeneration is not a normal phenomenon in elderly persons, and it may be an important sign in the early stages of progression of AD. METHODS: Thirty-four participants aged between 60 and 86 years were recruited for an experiment with a 3 × 4 × 2 factorial design that was conducted to explore the differences in semantic memory performance among controls with normal cognitive performance (NC), individuals classified as mildly cognitively impaired (MCI), and individuals with AD. RESULTS: The performance of participants diagnosed with mild AD was poorest for the attribute category, and there was no difference in response to different word frequencies. Although those diagnosed with MCI performed similarly to healthy elderly participants in terms of semantic memory, their performance profiles for different semantic hierarchies were similar to those of participants with AD. CONCLUSION: Semantic memory had degraded among participants with AD and MCI, and the rate of semantic degeneration was different in different semantic hierarchies.

Measurement of tissue-radiation dosage using a thermal steady-state elastic shear wave.

A biodosimeter based on thermal-induced elastic shear wave (TIESW) in silicone acellular porcine dermis (SAPD) at thermal steady state has been proposed and demonstrated. A square slab SAPD treated with ionizing radiation was tested. The SAPD becomes a continuous homogeneous and isotropic viscoelastic medium due to the generation of randomly coiled collagen fibers formed from their bundle-like structure in the dermis. A harmonic TIESW then propagates on the surface of the SAPD as measured by a nanometer-scaled strain-stress response under thermal equilibrium conditions at room temperature. TIESW oscillation frequency was noninvasively measured in real time by monitoring the transverse displacement of the TIESW on the SAPD surface. Because the elastic shear modulus is highly sensitive to absorbed doses of ionizing radiation, this proposed biodosimeter can become a highly sensitive and noninvasive method for quantitatively determining tissue-absorbed dosage in terms of TIESW's oscillation frequency. Detection sensitivity at 1 cGy and dynamic ranges covering 1 to 40 cGy and 80 to 500 cGy were demonstrated.

The distribution of apolipoprotein E gene polymorphism in Chinese civil aircrews, and a possible risk factor to their overweight and dyslipidemia is cumulative flight time.

BACKGROUND: The prevalence of dyslipidemia and overweight is significantly higher in aircrews than that in general population. The purpose of the study was to examine the distribution of APOE gene polymorphism and the influence of which as well as occupational environment on dyslipidemia and overweight in Chinese civil aircrews. METHODS: APOE gene polymorphism was investigated using PCR-RFLP, plasma lipid parameters were measured by standard enzymatic kits and personal information of the aircrews was collected through questionnaires. RESULTS: The allele frequencies among aircrews were ε2: 17.0%, ε3: 80.9%, and ε4: 2.1%, APOE gene polymorphism was associated with significant differences in TC and LDL-C. E2 individuals had the lowest TC and LDL-C concentrations, and E4 participants had the highest levels (p<0.001). In addition, the TC and LDL-C concentrations, as well as BMI rose with the increasing cumulative flying hours (p<0.05). The further logistic regression analysis showed the significant associations of BMI and dyslipidemia (p<0.0001, OR=2.093), cumulative flight time and overweight (p<0.0001, OR=1.560). CONCLUSIONS: The distribution of APOE alleles among aircrews was provided for the first time, which is not fully identical with that among general population. These data also suggested the cumulative flight time influenced dyslipidemia and overweight as an environmental contributor.

[Distribution characteristics of ApoB3'VNTR and hyperlipemia correlation factors in civil aircrew].

OBJECTIVE: To study the frequency distribution in polymorphism of the apoprotein B 3' variable number tandem repeat (ApoB3'VNTR) and influence factors on hyperlipemia in civil aircrew. METHODS: ApoB genotypes were determined by PCR technology and agarose gel electrophoresis. The blood lipids were measured by routine kits. Personal information of flight personnel was collected by questionnaire. RESULTS: Prevalence of the total dyslipidemia (49.5%) and overweight (55.6%) of flight personnel were much higher than that of domestic general population (29.2% and 49.1%) respectively (P < 0.05). There were 16 alleles and 54 kinds of genotypes of ApoB3'VNTR in the 682 flight personnel. The frequency distribution of alleles and genotypes of aircrew in the two air companies had same trend, which was different from the general population. The frequency of the homozygote was 76.54%, which was much higher than that of the other peoples home and abroad (21.50%). The frequency of the big allele (VNTR > or =39) in hyperlipemia groups were higher than that of normal groups. By analysis of co-variance, the body mass index (BMI), low density lipoprotein (LDL) and the total cholesterol(TC) increased with the cumulate flight hours (P < 0.05). In multivariate logistic regression analysis, the BMI was the only factor influencing blood lipids, and the cumulate flight hours was only factors affecting the BMI. Taking the cumulate flight hours logarithm as the independent variable(X), and the BMI as dependent variable(Y), the linearity equations was: Y = 2.730X + 13.584 (R2 = 0.159, P < 0.01). CONCLUSION: There are perhaps special genetic characteristics in the polymorphism of the ApoB3'VNTR in the aircrew. The big allele is correlated with the hyperlipemia. The flight burden not only directly affects the BMI and blood lipids levels, but also it can indirectly affect the lipids levels by BMI.

Genomic organization of the chicken CD8 locus reveals a novel family of immunoreceptor genes.

The genomic organization of the chicken CD8alpha gene was investigated to determine the basis of its polymorphism. Contiguous to the CD8alpha gene we identified multiple DNA blocks possessing sequences homologous to CD8alpha. Gene conversions and recombination over evolutionary time among CD8alpha and these CD8alpha homologous genes seem to account for the observed polymorphism. Furthermore, these CD8alpha-like DNAs encode a distinct multigene family of immunoreceptors that have a charged or polar residue in place of the interspecies-conserved CD8alpha transmembrane proline residue and a short cytoplasmic tail nonhomologous to CD8alpha. The identification of this novel multigene family with an organization reminiscent of human killer Ig-like receptors raises compelling questions on their evolutionary relationship among immunoreceptors.

[Effect of flying burthen on blood lipid in civil aviation aircrew].

OBJECTIVE: To investigate the effect of flying burthen on blood lipid level in civil aviation flight personnel. METHODS: The level of total cholesterol (TC), triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) were determined by kits. The relationship between the blood lipid levels and the flight personnel's flying hours, body weight index, smoking, drinking and sport were investigated. RESULTS: The average annual flying hours of hyperlipidemia group [(561.14 +/- 234.90) h] was significantly higher than that of non-hyperlipidemia group [(500.62 +/- 243.65) h] (P < 0.05). The level of TG of the average annual flying hours more 800 h [(1.61 +/- 0.10) mmol/L] were significantly higher than that of less than 400 h group [(1.31 +/- 0.65) mmol/L]. The morbidity rate of hyperlipidemia among the age 30 to 39 years old flight personnel was the highest. CONCLUSION: The average annual flying hours is one of primary factors affecting blood lipid in flight personnel.

[A simple method for estimating cosmic radiation effective dose rate].

OBJECTIVE: To study a simple method for estimating cosmic radiation effective dose rate for aircrew. METHOD: Using a new program by written in Object Pascal language on PC in Windows operation system on the basis of an algorithm designed in this paper, cosmic radiation effective dose rates at various altitudes and latitudes were calculated and compared with those obtained by using CARI-6 and FLUKA. RESULT: The calculated results by using the simple method agree remarkably with those calculated by using CARI-6 and FLUKA, in three groups of data compared with CARI-6, differences are within 25% for 76%, 71% and 100% of the data respectively; in the group of data compared with FLUKA, differences are all within 20%. CONCLUSION: The simple method is applicable in estimating cosmic radiation effective dose rate for flight altitude of 7000 to 20,000 m.

[Estimated cosmic radiation doses for flight personnel].

Objective. To calculate individual annual cosmic radiation effective dose for monitored flight personnel. Method. With the help of aircraft flight information from flight performance manual, software CARI-6 developed by U.S. Federal Aviation Administration was used to calculate the effective dose of galactic cosmic radiation along the air lines, and to calculate the effective dose rate on the ground in Urumuqi, then individual annual cosmic radiation dose on flight personnel was estimated from the data calculated by CARI-6. Result. The annual cosmic radiation dose on the ground at Urumuqi was 0.420 mSv a-1. The average effective dose rate of all flights of Xinjiang Airlines from 1997 to 1999 was 2.381 microSv h -1(0.33-3. 64 microSv h-1). Average annual cosmic radiation dose on flight personnel was 2.193 mSv a-1 (0.887-4.419 mSv a-1). Conclusion. Annual individual doses of all monitored flight personnel are well below the limit 20 mSv a-1 recommended by International Commission on Radiological Protection (ICRP).