63 research outputs found

    Magneto-optical absorption coefficients in monolayer MoSe2

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    We study the linear, third-order nonlinear, and total absorption coefficients (OACs) caused by intra- and inter-band transitions in monolayer MoSe2 in the presence of a magnetic field by using the compact density matrix approach. The results show that the OACs display the blue-shift behaviour with an increase in the magnetic field. The Zeeman fields do not affect the peak positions but reduce peak intensities slightly. Besides, the strong spin-orbit coupling in monolayer MoSe2 causes the peaks to differ significantly due to spin-up and spin-down. The OACs due to intra-band transition display only one peak in the THz range, while the inter-band spectra show a series of peaks in the near-infrared optical range, making monolayer MoSe2 a promising candidate for novel optoelectronic applications

    What Can we Learn about Improving Gifted Identification by Studying how Accurate the Process is in Arkansas?

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    How might we improve gifted and talented (G/T) identification by learning about the process in Arkansas (AR)? In this study, we examined the accuracy of the gifted identification process in AR by comparing the degree to which students who were academically talented in the top 5% on the 3 rd grade state assessment in reading and mathematics in AR were identified for G/T. Across five years of independent cohorts, we replicate the finding that roughly 30% of the students in the top 5% in both reading and mathematics on the 3 rd grade state assessment are not identified as G/T. Multivariate models indicate that high achieving students participating in the Federal Free/Reduced Lunch program were 11 percentage points less likely to be identified as G/T. Our study has policy implications for AR’s G/T screening strategies, and more broadly for G/T identification of low-income and historically marginalized groups. Using student achievement on the 3rd grade state assessment in reading and mathematics as a ‘universal screening’ tool could help these students receive the academic services they need to develop their talent to the fullest

    The clinical features of osteogenesis imperfecta in Vietnam

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    Purpose Osteogenesis imperfecta (OI) has not been studied in a Vietnamese population before. The aim of this study was to systematically collect epidemiological information, investigate clinical features and create a clinical database of OI patients in Vietnam for future research and treatment strategy development. Method Participants underwent clinical and physical examinations; also medical records were reviewed. Genealogical information was collected and family members’ phenotypical manifestations recorded. Cases were classified according to the Sillence classification. Results In total, 146 OI patients from 120 families were studied: 46 with OI Type I, 46 with Type III and 54 with Type IV. Almost patients had skeletal deformations. One hundred and forty-two had a history of fractures, 117 blue sclera, 89 dentinogenesis imperfecta and 26 hearing loss. The total number of fractures was 1,932. Thirty-four patients had intra-uterine fractures and nine had perinatal fractures. Surgery was performed 163 times in 58 patients; 100 osteosyntheses and 63 osteotomies. Bisphosphonate treatment was used in 37 patients. The number of affected individuals and predominance of severe forms of OI indicate that the disease is under diagnosed in Vietnam, especially in cases without a family history or with mild form of OI. Deformities appeared in all patients with different severity and localisation, affecting mostly the lower limbs. OI medical and surgical treatment rates are low and in most cases surgery was performed due to fractures. Conclusions Compared to previous studies, our results indicate a lower OI prevalence and greater severity of symptoms in the Vietnamese population when compared with other areas. Further investigation, improved diagnosis and treatment are needed to increase the patients’ quality of life

    Point-of-care C-reactive protein testing to reduce inappropriate use of antibiotics for non-severe acute respiratory infections in Vietnamese primary health care: a randomised controlled trial

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    Background Inappropriate antibiotic use for acute respiratory tract infections is common in primary health care, but distinguishing serious from self-limiting infections is diffi cult, particularly in low-resource settings. We assessed whether C-reactive protein point-of-care testing can safely reduce antibiotic use in patients with non-severe acute respiratory tract infections in Vietnam. Method We did a multicentre open-label randomised controlled trial in ten primary health-care centres in northern Vietnam. Patients aged 1–65 years with at least one focal and one systemic symptom of acute respiratory tract infection were assigned 1:1 to receive either C-reactive protein point-of-care testing or routine care, following which antibiotic prescribing decisions were made. Patients with severe acute respiratory tract infection were excluded. Enrolled patients were reassessed on day 3, 4, or 5, and on day 14 a structured telephone interview was done blind to the intervention. Randomised assignments were concealed from prescribers and patients but not masked as the test result was used to assist treatment decisions. The primary outcome was antibiotic use within 14 days of follow-up. All analyses were prespecifi ed in the protocol and the statistical analysis plan. All analyses were done on the intention-totreat population and the analysis of the primary endpoint was repeated in the per-protocol population. This trial is registered under number NCT01918579. Findings Between March 17, 2014, and July 3, 2015, 2037 patients (1028 children and 1009 adults) were enrolled and randomised. One adult patient withdrew immediately after randomisation. 1017 patients were assigned to receive C-reactive protein point-of-care testing, and 1019 patients were assigned to receive routine care. 115 patients in the C-reactive protein point-of-care group and 72 patients in the routine care group were excluded in the intention-to-treat analysis due to missing primary endpoint. The number of patients who used antibiotics within 14 days was 581 (64%) of 902 patients in the C-reactive protein group versus 738 (78%) of 947 patients in the control group (odds ratio [OR] 0·49, 95% CI 0·40–0·61; p<0·0001). Highly signifi cant diff erences were seen in both children and adults, with substantial heterogeneity of the intervention eff ect across the 10 sites (I²=84%, 95% CI 66–96). 140 patients in the C-reactive protein group and 137 patients in the routine care group missed the urine test on day 3, 4, or 5. Antibiotic activity in urine on day 3, 4, or 5 was found in 267 (30%) of 877 patients in the C-reactive protein group versus 314 (36%) of 882 patients in the routine treatment group (OR 0·78, 95% CI 0·63–0·95; p=0·015). Time to resolution of symptoms was similar in both groups. Adverse events were rare, with no deaths and a total of 14 hospital admissions (six in the C-reactive protein group and eight in the control group). Interpretation C-reactive protein point-of-care testing reduced antibiotic use for non-severe acute respiratory tract infection without compromising patients’ recovery in primary health care in Vietnam. Health-care providers might have become familiar with the clinical picture of low C-reactive protein, leading to reduction in antibiotic prescribing in both groups, but this would have led to a reduction in observed eff ect, rather than overestimation. Qualitative analysis is needed to address diff erences in context in order to implement this strategy to improve rational antibiotic use for patients with acute respiratory infection in low-income and middle-income countries

    The epidemiology and aetiology of diarrhoeal disease in infancy in southern Vietnam: a birth cohort study.

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    OBJECTIVES: Previous studies indicate a high burden of diarrhoeal disease in Vietnamese children, however longitudinal community-based data on burden and aetiology are limited. The findings from a large, prospective cohort study of diarrhoeal disease in infants in southern Vietnam are presented herein. METHODS: Infants were enrolled at birth in urban Ho Chi Minh City and a semi-rural district in southern Vietnam, and followed for 12 months (n=6706). Diarrhoeal illness episodes were identified through clinic-based passive surveillance, hospital admissions, and self-reports. RESULTS: The minimum incidence of diarrhoeal illness in the first year of life was 271/1000 infant-years of observation for the whole cohort. Rotavirus was the most commonly detected pathogen (50% of positive samples), followed by norovirus (24%), Campylobacter (20%), Salmonella (18%), and Shigella (16%). Repeat infections were identified in 9% of infants infected with rotavirus, norovirus, Shigella, or Campylobacter, and 13% of those with Salmonella infections. CONCLUSIONS: The minimum incidence of diarrhoeal disease in infants in both urban and semi-rural settings in southern Vietnam was quantified prospectively. A large proportion of laboratory-diagnosed disease was caused by rotavirus and norovirus. These data highlight the unmet need for a rotavirus vaccine in Vietnam and provide evidence of the previously unrecognized burden of norovirus in infants

    Self-reported use of tobacco products in nine rural INDEPTH Health and Demographic Surveillance Systems in Asia

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    BACKGROUND: Tobacco use is the most preventable cause of premature death and disability. Even though tobacco use is common in many Asian countries, reliable and comparable data on the burden imposed by tobacco use in this region are sparse, and surveillance systems to track trends are in their infancy. OBJECTIVE: To assess and compare the prevalence of tobacco use and its associated factors in nine selected rural sites in five Asian countries. METHODS: Tobacco use among 9,208 men and 9,221 women aged 25-64 years in nine Health and Demographic Surveillance System (HDSS) sites in five Asian countries of the INDEPTH Network were examined in 2005 as part of a broader survey of the major chronic non-communicable disease risk factors. All sites used a standardised protocol based on the WHO STEPS approach to risk factor surveillance; expanded questions of local relevance, including chewing tobacco, were also included. Multivariable logistic regression was used to assess demographic factors associated with tobacco use. RESULTS: Tobacco use, whether smoked or chewed, was common across all sites with some notable variations. More than 50% of men smoked daily; this applied to almost all age groups. Few women smoked daily in any of the sites. However, women were more likely to chew tobacco than men in all sites except Vadu in India. Tobacco use in men began in late adolescence in most of the sites and the number of cigarettes smoked daily ranged from three to 15. Use of both forms of tobacco, smoked and chewed, was associated with age, gender and education. Men were more likely to smoke compared to women, smoking increased with age in the four sites in Bangladesh but not in other sites and with low level of education in all the sites. CONCLUSION: The prevalence of tobacco use, regardless of the type of tobacco, was high among men in all of these rural populations with tobacco use started during adolescence in all HDSS sites. Innovative communication strategies for behaviour change targeting adolescents in schools and adult men and women at work or at home, may create a mass awareness about adverse health consequences of tobacco smoking or chewing tobacco. Such efforts, to be effective, however, need to be supported by strong legislation and leadership. Only four of the five countries involved in this multi-site study have ratified the Framework Convention on Tobacco Control, and even where it has been ratified, implementation is uneven.Supplement: 1</p

    Intensified treatment with high dose Rifampicin and Levofloxacin compared to standard treatment for adult patients with Tuberculous Meningitis (TBM-IT): protocol for a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Tuberculous meningitis is the most severe form of tuberculosis. Mortality for untreated tuberculous meningitis is 100%. Despite the introduction of antibiotic treatment for tuberculosis the mortality rate for tuberculous meningitis remains high; approximately 25% for HIV-negative and 67% for HIV positive patients with most deaths occurring within one month of starting therapy. The high mortality rate in tuberculous meningitis reflects the severity of the condition but also the poor antibacterial activity of current treatment regimes and relatively poor penetration of these drugs into the central nervous system. Improving the antitubercular activity in the central nervous system of current therapy may help improve outcomes. Increasing the dose of rifampicin, a key drug with known poor cerebrospinal fluid penetration may lead to higher drug levels at the site of infection and may improve survival. Of the second generation fluoroquinolones, levofloxacin may have the optimal pharmacological features including cerebrospinal fluid penetration, with a ratio of Area Under the Curve (AUC) in cerebrospinal fluid to AUC in plasma of >75% and strong bactericidal activity against <it>Mycobacterium tuberculosis</it>. We propose a randomized controlled trial to assess the efficacy of an intensified anti-tubercular treatment regimen in tuberculous meningitis patients, comparing current standard tuberculous meningitis treatment regimens with standard treatment intensified with high-dose rifampicin and additional levofloxacin.</p> <p>Methods/Design</p> <p>A randomized, double blind, placebo-controlled trial with two parallel arms, comparing standard Vietnamese national guideline treatment for tuberculous meningitis with standard treatment <it>plus </it>an increased dose of rifampicin (to 15 mg/kg/day total) and additional levofloxacin. The study will include 750 patients (375 per treatment group) including a minimum of 350 HIV-positive patients. The calculation assumes an overall mortality of 40% vs. 30% in the two arms, respectively (corresponding to a target hazard ratio of 0.7), a power of 80% and a two-sided significance level of 5%. Randomization ratio is 1:1. The primary endpoint is overall survival, i.e. time from randomization to death during a follow-up period of 9 months. Secondary endpoints are: neurological disability at 9 months, time to new neurological event or death, time to new or recurrent AIDS-defining illness or death (in HIV-positive patients only), severe adverse events, and rate of treatment interruption for adverse events.</p> <p>Discussion</p> <p>Currently very few options are available for the treatment of TBM and the mortality rate remains unacceptably high with severe disabilities seen in many of the survivors. This trial is based on the hypothesis that current anti-mycobacterial treatment schedules for TBM are not potent enough and that outcomes will be improved by increasing the CSF penetrating power of this regimen by optimising dosage and using additional drugs with better CSF penetration.</p> <p>Trial registration</p> <p>International Standard Randomised Controlled Trial Number <a href="http://www.controlled-trials.com/ISRCTN61649292">ISRCTN61649292</a></p

    Genomic signatures of human and animal disease in the zoonotic pathogen Streptococcus suis

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    Streptococcus suis causes disease in pigs worldwide and is increasingly implicated in zoonotic disease in East and South-East Asia. To understand the genetic basis of disease in S. suis, we study the genomes of 375 isolates with detailed clinical phenotypes from pigs and humans from the United Kingdom and Vietnam. Here, we show that isolates associated with disease contain substantially fewer genes than non-clinical isolates, but are more likely to encode virulence factors. Human disease isolates are limited to a single-virulent population, originating in the 1920 s when pig production was intensified, but no consistent genomic differences between pig and human isolates are observed. There is little geographical clustering of different S. suis subpopulations, and the bacterium undergoes high rates of recombination, implying that an increase in virulence anywhere in the world could have a global impact over a short timescale.Peer reviewe

    A common variant near TGFBR3 is associated with primary open angle glaucoma

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    Primary open angle glaucoma (POAG), a major cause of blindness worldwide, is a complex disease with a significant genetic contribution. We performed Exome Array (Illumina) analysis on 3504 POAG cases and 9746 controls with replication of the most significant findings in 9173 POAG cases and 26 780 controls across 18 collections of Asian, African and European descent. Apart from confirming strong evidence of association at CDKN2B-AS1 (rs2157719 [G], odds ratio [OR] = 0.71, P = 2.81 × 10−33), we observed one SNP showing significant association to POAG (CDC7–TGFBR3 rs1192415, ORG-allele = 1.13, Pmeta = 1.60 × 10−8). This particular SNP has previously been shown to be strongly associated with optic disc area and vertical cup-to-disc ratio, which are regarded as glaucoma-related quantitative traits. Our study now extends this by directly implicating it in POAG disease pathogenesis
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