912 research outputs found
Janus monolayers of transition metal dichalcogenides.
Structural symmetry-breaking plays a crucial role in determining the electronic band structures of two-dimensional materials. Tremendous efforts have been devoted to breaking the in-plane symmetry of graphene with electric fields on AB-stacked bilayers or stacked van der Waals heterostructures. In contrast, transition metal dichalcogenide monolayers are semiconductors with intrinsic in-plane asymmetry, leading to direct electronic bandgaps, distinctive optical properties and great potential in optoelectronics. Apart from their in-plane inversion asymmetry, an additional degree of freedom allowing spin manipulation can be induced by breaking the out-of-plane mirror symmetry with external electric fields or, as theoretically proposed, with an asymmetric out-of-plane structural configuration. Here, we report a synthetic strategy to grow Janus monolayers of transition metal dichalcogenides breaking the out-of-plane structural symmetry. In particular, based on a MoS2 monolayer, we fully replace the top-layer S with Se atoms. We confirm the Janus structure of MoSSe directly by means of scanning transmission electron microscopy and energy-dependent X-ray photoelectron spectroscopy, and prove the existence of vertical dipoles by second harmonic generation and piezoresponse force microscopy measurements
Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.
BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
Hsa-miRNA-765 as a key mediator for inhibiting growth, migration and invasion in fulvestrant-treated prostate cancer
Fulvestrant (ICI-182,780) has recently been shown to effectively suppress prostate cancer cell growth in vitro and in vivo. But it is unclear whether microRNAs play a role in regulating oncogene expression in fulvestrant-treated prostate cancer. Here, this study reports hsa-miR-765 as the first fulvestrant-driven, ERβ-regulated miRNA exhibiting significant tumor suppressor activities like fulvestrant, against prostate cancer cell growth via blockage of cell-cycle progression at the G2/M transition, and cell migration and invasion possibly via reduction of filopodia/intense stress-fiber formation. Fulvestrant was shown to upregulate hsa-miR-765 expression through recruitment of ERβ to the 5′-regulatory-region of hsa-miR-765. HMGA1, an oncogenic protein in prostate cancer, was identified as a downstream target of hsa-miR-765 and fulvestrant in cell-based experiments and a clinical study. Both the antiestrogen and the hsa-miR-765 mimic suppressed HMGA1 protein expression. In a neo-adjuvant study, levels of hsa-miR-765 were increased and HMGA1 expression was almost completely lost in prostate cancer specimens from patients treated with a single dose (250 mg) of fulvestrant 28 days before prostatectomy. These findings reveal a novel fulvestrant signaling cascade involving ERβ-mediated transcriptional upregulation of hsa-miR-765 that suppresses HMGA1 protein expression as part of the mechanism underlying the tumor suppressor action of fulvestrant in prostate cancer. © 2014 Leung et al
Observation of CR Anisotropy with ARGO-YBJ
The measurement of the anisotropies of cosmic ray arrival direction provides
important informations on the propagation mechanisms and on the identification
of their sources. In this paper we report the observation of anisotropy regions
at different angular scales. In particular, the observation of a possible
anisotropy on scales between 10 and 30
suggests the presence of unknown features of the magnetic fields the charged
cosmic rays propagate through, as well as potential contributions of nearby
sources to the total flux of cosmic rays. Evidence of new weaker few-degree
excesses throughout the sky region R.A. is
reported for the first time.Comment: Talk given at 12th TAUP Conference 2011, 5-9 September 2011, Munich,
German
A cotton miRNA is involved in regulation of plant response to salt stress
The present study functionally identified a new microRNA (microRNA ovual line 5, miRNVL5) with its target gene GhCHR from cotton (Gossypium hirsutum). The sequence of miRNVL5 precursor is 104 nt long, with a well developed secondary structure. GhCHR contains two DC1 and three PHD Cys/His-rich domains, suggesting that GhCHR encodes a zinc-finger domain-containing transcription factor. miRNVL5 and GhCHR express at various developmental stages of cotton. Under salt stress (50–400 mM NaCl), miRNVL5 expression was repressed, with concomitant high expression of GhCHR in cotton seedlings. Ectopic expression of GhCHR in Arabidopsis conferred salt stress tolerance by reducing Na+ accumulation in plants and improving primary root growth and biomass. Interestingly, Arabidopsis constitutively expressing miRNVL5 showed hypersensitivity to salt stress. A GhCHR orthorlous gene At2g44380 from Arabidopsis that can be cleaved by miRNVL5 was identified by degradome sequencing, but no confidential miRNVL5 homologs in Arabidopsis have been identified. Microarray analysis of miRNVL5 transgenic Arabidopsis showed six downstream genes (CBF1, CBF2, CBF3, ERF4, AT3G22920, and AT3G49200), which were induced by salt stress in wild-type but repressed in miRNVL5-expressing Arabidopsis. These results indicate that miRNVL5 is involved in regulation of plant response to salt stress
Evolutionarily Optimized Electromagnetic Sensor Measurements for Robust Surgical Navigation
© 2001-2012 IEEE. Miniaturized electromagnetic sensors are increasingly introduced to navigate surgical instruments to anatomical targets during minimally invasive procedures, such as endoscopic surgery. These sensors are usually attached at the distal tips of surgical instruments to track their three-dimensional motion represented by the position and orientation in six degrees of freedom. Unfortunately, these sensors suffer from inaccurate measurements and jitter errors due to the patient movement (e.g., respiratory motion) and magnetic field distortion. This paper proposes an evolutionary computing strategy to optimize the sensor measurements and improve the tracking accuracy of surgical navigation. We modified two evolutionary computation algorithms and proposed adaptive particle swarm optimization (APSO) and observation-boosted differential evolution (OBDE) to enhance the navigation accuracy. The experimental results demonstrate that our modified algorithms to evolutionarily optimize electromagnetic sensor measurements can critically reduce the tracking error from 4.8 to 2.9 mm. In particular, OBDE outperforms APSO for electromagnetic endoscopic navigation
The Association between Cardiorespiratory Fitness and Gut Microbiota Composition in Premenopausal Women
The aim of this study was to investigate the association between cardiorespiratory fitness and gut microbiota composition in premenopausal women. The participants consisted of 71 premenopausal Finnish women ( aged 19-49 years). Gut microbiota were analyzed using flow cytometry, 16S rRNA gene hybridization and DNA-staining. Maximum oxygen uptake (VO2max) was assessed by respiratory gas analyzer and body composition by Bioimpdance. We found that participants with low VO2max had lower Bacteroides, but higher Eubacterium rectale-Clostridium coccoides than the high VO2max group (p < 0.05 for all). VO2max was inversely associated with EreC (r = 0.309, p = 0.01) but not with other bacteria. VO2max also negatively correlated with fat% (r = 0.755, p < 0.001), triglycerides (r = -0.274, p = 0.021) and leptin (r = -0.574, p < 0.001). By contrast, EreC was positively associated with fat% (r = 0.382, p = 0.002), dietary fat intake (r = 0.258, p = 0.034), triglycerides (r = 0.390, p = 0.002) and leptin (r = 0.424, p = 0.001), but negatively with carbohydrate intake (r = -0.252, p = 0.034) and HDL (r = -0.26, p = 0.028). After adjusting for age and dietary intake, all the significant associations remained. However, after adjusting for fat%, the associations between VO2max and EreC disappeared. Our results suggest that cardiorespiratory fitness is associated with gut microbiota composition, independent of age and carbohydrate or fat intake. The association between VO2max and EreC, however, appears to be mediated by body fatness
Observation of the cosmic ray moon shadowing effect with the ARGO-YBJ experiment
Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called Moon shadow). The Moon shadow is an important tool to determine the performance of an air shower array. Indeed, the westward displacement of the shadow center, due to the bending effect of the geomagnetic field on the propagation of cosmic rays, allows the setting of the absolute rigidity scale of the primary particles inducing the showers recorded by the detector. In addition, the shape of the shadow permits to determine the detector point spread function, while the position of the deficit at high energies allows the evaluation of its absolute pointing accuracy. In this paper we present the observation of the cosmic ray Moon shadowing effect carried out by the ARGO-YBJ experiment in the multi-TeV energy region with high statistical significance (55 standard deviations). By means of an accurate Monte Carlo simulation of the cosmic rays propagation in the Earth-Moon system, we have studied separately the effect of the
geomagnetic field and of the detector point spread function on the observed shadow. The angular resolution as a function of the particle multiplicity and the pointing accuracy have been obtained. The primary energy of detected showers has been estimated by measuring the westward displacement as a function of the particle multiplicity, thus calibrating the relation between shower size and cosmic ray energy. The stability of the detector on a monthly basis has been checked by monitoring the position and the deficit of the Moon shadow. Finally, we have studied with high statistical accuracy the shadowing effect in the ''day/night’’ time looking for possible effect induced by the solar wind
Highlights from the ARGO-YBJ experiment
The ARGO-YBJ experiment at YangBaJing in Tibet (4300 m a.s.l.) has been taking data with its full layout since October 2007. Here we present a few significant results obtained in gamma-ray astronomy and cosmic-ray physics. Emphasis is placed on the analysis of gamma-ray emission from point-like sources (Crab Nebula, MRK 421), on the preliminary limit on the antiproton/proton flux ratio, on the large-scale cosmic-ray anisotropy and on the proton–air cross-section. The performance of the detector is also discussed, and the perspectives of the experiment are outlined
The Efficacy and Safety of Minocycline‐Containing Quadruple Therapies Against Helicobacter pylori Infection: A Retrospective Cohort Study
Xiao-Bei Si,1,2 Ling-Yun Zhang,2 Shuo Yang,3 Xiao-Lu Chen,2 Yan-Yan Shi,4 Yu Lan,2 Shi-Gang Ding1 1Department of Gastroenterology, Peking University Third Hospital, Beijing, People’s Republic of China; 2Department of Gastroenterology, Beijing Jishuitan Hospital, Capital Medical University, Beijing, People’s Republic of China; 3Department of Pharmacy, Beijing Jishuitan Hospital, Capital Medical University, Beijing, People’s Republic of China; 4Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing, People’s Republic of ChinaCorrespondence: Shi-Gang Ding, Department of Gastroenterology, Peking University Third Hospital, Beijing, People’s Republic of China, Email [email protected] Yu Lan, Department of Gastroenterology, Beijing Jishuitan Hospital, Capital Medical University, Beijing, People’s Republic of China, Email [email protected]: Minocycline, a derivative of tetracycline, has anti-Helicobacter pylori (H. pylori) properties and can be used to treat H. pylori infection. However, only a few randomized controlled trials (RCTs) have investigated the efficacy of minocycline-containing quadruple therapy (MCQT) in treating H. pylori infection. This study aimed to determine the efficacy and safety of MCQT and investigate the factors influencing both aspects.Methods: This was a retrospective cohort study. Patients diagnosed with H. pylori infection between January 1, 2022, and July 31, 2023 at. The primary outcome was the eradication rate of H. pylori, and the secondary outcome was the number and type of adverse events.Results: A total of 828 patients were included in this study. The overall H. pylori eradication rate among the included patients at 95% confidence interval (CI) (Range 0.864 to 0.907) was 88.53%. The H. pylori eradication rate for patients who received MCQT regimen as the primary therapy was 92.28% (95% CI: 0.901– 0.945), significantly higher than that of patients who received MCQT as rescue therapy (80.81%; 95% CI: 0.761– 0.855, P= 0.003). Adverse events, including dizziness, abdominal distension, diarrhea, nausea, abdominal discomfort, constipation, headache, rash, sleep disorder, palpitation, backache, and anorexia, occurred in 185 (22.34%) patients, with dizziness being the most common (75/828, 9.06%). Compliance with MCQT therapy was an independent factor influencing H. pylori eradication in patients receiving MCQT as a primary therapy. Compliance and presence or absence of H. pylori infection symptoms at the time of screening were independent factors influencing H. Pylori eradication in patients receiving MCQT as rescue therapy. Factors that influenced the occurrence of adverse events included reasons for H. pylori infection screening, residence, treatment compliance, and the use of acid-suppressant regimens.Conclusion: MCQT regimens were effective in H. pylori infection eradication, and the treatment resulted only in fewer adverse events when used as primary or rescue therapies for H. pylori infection treatment. Future prospective studies with larger sample sizes and more comprehensive data are needed to validate our findings.Keywords: Helicobacter pylori, minocycline, cohort stud
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