274 research outputs found
Panoramic-reconstruction temporal imaging for seamless measurements of slowly-evolved femtosecond pulse dynamics
Single-shot real-time characterization of optical waveforms with
sub-picosecond resolution is essential for investigating various ultrafast
optical dynamics. However, the finite temporal recording length of current
techniques hinders comprehensive understanding of many intriguing ultrafast
optical phenomena that evolve over a time scale much longer than their fine
temporal details. Inspired by the space-time duality and by stitching of
multiple microscopic images to achieve a larger field of view in the spatial
domain, here a panoramic-reconstruction temporal imaging (PARTI) system is
devised to scale up the temporal recording length without sacrificing the
resolution. As a proof-of-concept demonstration, the PARTI system is applied to
study the dynamic waveforms of slowly-evolved dissipative Kerr solitons in an
ultrahigh-Q microresonator. Two 1.5-ns-long comprehensive evolution portraits
are reconstructed with 740-fs resolution and dissipative Kerr soliton
transition dynamics, in which a multiplet soliton state evolves into stable
singlet soliton state, are depicted
Aging and loss decision making: increased risk aversion and decreased use of maximizing information, with correlated rationality and value maximization
Frontiers in Human Neuroscience9May1-1
Liver Transplantation in an Adult with Citrullinaemia Type 2
Citrullinaemia is a urea cycle defect that results from a deficiency of the enzyme arginosuccinate synthetase. Type 1 disease is diagnosed in childhood, whereas Type 2 disease is adult onset. We report the outcome of a patient with citrullinemia Type 2 who received a liver transplant at our center and the implications of this diagnosis in liver transplantation
High-reflectivity, high-Q micromechanical membranes via guided resonances for enhanced optomechanical coupling
Using Fano-type guided resonances (GRs) in photonic crystal (PhC) slab
structures, we numerically and experimentally demonstrate optical reflectivity
enhancement of high-Q SiNx membrane-type resonators used in
membrane-in-the-middle optomechanical (OM) systems. Normal-incidence
transmission and mechanical ringdown measurements of 50-nm-thick PhC membranes
demonstrate GRs near 1064 nm, leading to a ~ 4\times increase in reflectivity
while preserving high mechanical Q factors of up to ~ 5 \times 10^6. The
results would allow improvement of membrane-in-the-middle OM systems by virtue
of increased OM coupling, presenting a path towards ground state cooling of
such a membrane and observations of related quantum effects
Antimicrobial resistance of Listeria monocytogenes and Salmonella Enteritidis isolated from vegetable farms and retail markets in Malaysia
Listeriosis and salmonellosis are the major foodborne illnesses worldwide. Over the last decade, increasing reports about the antibiotic resistance of Listeria monocytogenes and Salmonella from diverse sources have prompted public health concerns, especially in developing countries with over reliance or misuse of antibiotic drugs in the treatment of humans and animals. In this study, antibiotic susceptibility profiles of 58 L. monocytogenes and 12 Salmonella Enteritidis strains from vegetable farms and retail markets in Malaysia were tested by the standard disk diffusion method. Listeria monocytogenes isolates were found to exhibit 100% resistance to penicillin G. Also, high resistance patterns were observed for meropenem (70.7%) and rifampicin (41.4%). The multiple antibiotic resistance (MAR) index of L. monocytogenes isolates ranged from 0.11 to 0.56. Besides, the antibiogram results revealed that multidrug-resistant (MDR) S. Enteritidis were detected and all the S. Enteritidis isolates demonstrated resistance to at least four antibiotics. Ampicillin, amoxicillin, and trimethoprim failed to inhibit all the S. Enteritidis strains. Salmonella Enteritidis isolates also displayed high resistance to nalidixic acid (75.0%), trimethoprim-sulfamethoxazole (75.0%), and chloramphenicol (66.7%). Findings in this study indicated that vegetables could be potential sources of multidrug resistance of L. monocytogenes and S. Enteritidis, which can be a serious issue and a major concern for public health. Thus, there is a great need for surveillance programs in Malaysia to continuously monitor the antibiotic resistance profiles of important pathogens
Femtogram Doubly Clamped Nanomechanical Resonators Embedded in a High-Q Two-Dimensional Photonic Crystal Nanocavity
We demonstrate a new optomechanical device system which allows highly
efficient transduction of femtogram nanobeam resonators. Doubly clamped
nanomechanical resonators with mass as small as 25 fg are embedded in a
high-finesse two-dimensional photonic crystal nanocavity. Optical transduction
of the fundamental flexural mode around 1 GHz was performed at room temperature
and ambient conditions, with an observed displacement sensitivity of 0.94
fm/Hz^(1/2). Comparison of measurements from symmetric and asymmetric
double-beam devices reveals hybridization of the mechanical modes where the
structural symmetry is shown to be the key to obtain a high mechanical quality
factor. Our novel configuration opens the way for a new category of
"NEMS-in-cavity" devices based on optomechanical interaction at the nanoscale.Comment: Nano Lett. 201
Changes in pulmonary tuberculosis prevalence: Evidence from the 2010 population survey in a populous province of China
Background: This paper reports findings from the prevalence survey conducted in Shandong China in 2010, a province with a population of 94 million. This study aimed to estimate TB prevalence of the province in 2010 in comparison with the 2000 survey; and to compare yields of TB cases from different case finding approaches. Methods: A population based, cross-sectional survey was conducted using multi-stage random cluster sampling. 54,279 adults participated in the survey with a response rate of 96%. Doctors interviewed and classified participants as suspected TB cases if they presented with persistent cough, abnormal chest X-ray (CXRAY), or both. Three sputum specimens of all suspected cases were collected and sent for smear microscopy and culture. Results: Adjusted prevalence rate of bacteriologically confirmed cases was 34 per 100,000 for adults in Shandong in 2010. Compared to the 2000 survey, TB prevalence has declined by 80%. 53% of bacteriologically confirmed cases did not present persistent cough. The yield of bacteriologically confirmed cases was 47% by symptom screening and 95% by CXRAY. Over 50% of TB cases were among over 65's. Conclusions: The prevalence rate of bacteriologically confirmed cases was significantly reduced compared with 2000. The survey raised challenges to identify TB cases without clear symptoms
The changing seroepidemiology of enterovirus 71 infection among children and adolescents in Singapore
<p>Abstract</p> <p>Background</p> <p>Enterovirus 71 (EV71) has caused recurrent epidemics of hand, foot and mouth disease among children in Singapore. Between August 2008 and July 2010, we conducted a survey to estimate the seroprevalence of EV71 infection among children and adolescents aged 1-17 years. We compared our EV71 seroepidemiologic findings with a previous study conducted in 1996-1997.</p> <p>Methods</p> <p>The survey involved the prospective collection of 1,200 residual sera from Singapore residents aged 1-17 years in two hospitals. Neutralizing antibodies to EV71 were detected by the microneutralization test. The geometric mean titer (GMT) of EV71 antibodies and 95% confidence intervals (CI) were calculated and compared by age groups. Statistical significance was taken as <it>P </it>< 0.05.</p> <p>Results</p> <p>The overall EV71 antibody prevalence was 26.9% (95% CI: 24.5-29.5%). It increased significantly from 14.3% in children aged 1-6 years to 27.8% in those aged 7-12 years, and reached 38.8% in adolescents aged 13-17 years. The seroconversion rate differed by about 12% between the consecutive age groups. The GMT of EV71 antibodies was higher among primary school children aged 7-12 years in our study than that among the 6-12 year age group in the 1996-1997 study.</p> <p>Conclusions</p> <p>Higher antibody titers were observed in children aged 1-6 years than those in the other two age groups, indicating that most of the infections had been acquired during early childhood. EV71 infection is common among children and adolescents in Singapore, with 39% infected by the time they are in secondary school (13-17 years of age).</p
Seroepidemiology of coxsackievirus A6, coxsackievirus A16, and Enterovirus 71 infections among children and adolescents in Singapore, 2008-2010
10.1371/journal.pone.0127999PLoS ONE105e012799
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