BackgroundThe dominant viral etiologies responsible for acute respiratory infections (ARIs) are poorly understood, particularly among hospitalized children in resource-limited tropical countries where morbidity and mortality caused by ARIs are highest. Improved etiological insight is needed to improve clinical management and prevention.ObjectivesWe conducted a three-year prospective descriptive study of severe respiratory illness among children from 2 months to 13 years of age within the largest referral hospital for infectious diseases in southern Vietnam.MethodsMolecular detection for 15 viral species and subtypes was performed on three types of respiratory specimens (nose, throat swabs and nasopharyngeal aspirates) using a multiplex RT-PCR kit (Seeplex™ RV detection, Seegene) and additional monoplex real-time RT-PCRs.ResultsA total of 309 children were enrolled from November 2004 to January 2008. Viruses were identified in 72% (222/309) of cases, including respiratory syncytial virus (24%), influenza virus A and B (17%), human bocavirus (16%), enterovirus (9%), human coronavirus (8%), human metapneumovirus (7%), parainfluenza virus 1–3 (6%), adenovirus (5%), and human rhinovirus A (4%). Co-infections with multiple viruses were detected in 20% (62/309) of patients. When combined, diagnostic yields in nose and throat swabs were similar to nasopharyngeal aspirates.ConclusionSimilar to other parts in the world, RSV and influenza were the predominant viral pathogens detected in Vietnamese hospitalized children. Combined nasal and throat swabs are the specimens of choice for sensitive molecular detection of a broad panel of viral agents. Further research is required to better understand the clinical significance of single versus multiple viral coinfections and to address the role of bacterial (co-)infections involved in severe respiratory illness.

Highlights► A novel real-time RT-PCR using specific locked nucleic acid probes is described. ► The assay is quantitative and distinguishes RSV subgroup A & B. ► Compared with a commercial multiplex PCR using 264 respiratory samplesin Vietnam. ► Sensitivity was significantly higher with detection a rate of 32 vs. 24%.

An open randomized comparison of 2 days (Ofx2) versus 3 days (Ofx3) of oral ofloxacin treatment (15 mg/kg/ day) was conducted with Vietnamese children between 1 and 15 years of age with suspected typhoid fever. Of 108 children enrolled, 100 were blood culture positive for Salmonella typhi, and 86% of the isolates were multidrug resistant. There were no significant adverse effects. The therapeutic responses were similar in both groups, with mean (؎ standard deviation) fever clearances of 107 ؎ 60 h in the Ofx3 group and 100 ؎ 64 h in the Ofx2 group (P > 0.2). There were six ''clinical'' failures in the Ofx2 group and two clinical failures in the Ofx3 group (P > 0.2), in which fever and symptoms persisted for more than 1 week after the start of treatment, but only one of these was culture positive (Ofx3). There was one suspected relapse, and one carrier was identified. Short courses of ofloxacin are simple, inexpensive, safe, and effective for the treatment of uncomplicated multidrug-resistant typhoid fever.

Multilayer thin‐film dielectric capacitors with high energy‐storage performance and fast charge/discharge speed have significantly affected the development of miniaturized pulsed‐power devices. Here, the interfacial strain in epitaxial multilayers of antiferroelectric PbZrO3 and relaxor‐ferroelectric Pb0.9La0.1Zr0.52Ti0.48O3 is shown to significantly enhance the maximum polarization of the multilayer thin‐film capacitors, beyond that of the composing individual layers. Insights obtained from atomically resolved energy‐dispersive X‐ray spectroscopy and high‐resolution X‐ray diffraction analysis of the interface and domain structure are used to develop phenomenological models that explain the observed trends in breakdown strength and energy‐storage density as a function of multilayer period number. The underlying mechanism is the mechanical coupling between the layers that depends on the individual layer thicknesses. These factors result in a strongly enhanced recoverable energy‐storage density (increased by a factor of 4 to ≈128.4 J cm−3) with high efficiency (≈81.2%). Moreover, the multilayer films show almost fatigue‐free energy‐storage performance after 1010 switching cycles, even at elevated temperatures up to 220 °C, demonstrating their robustness. The outstanding properties show the great potential of epitaxial multilayers for energy‐storage applications, due to the well‐defined separate layers and coupling of properties across the interfaces, not present in ceramic composites.

This paper discusses similar-scale mechanical models of a thrips wing using microelectromechanical systems (MEMS) piezoresistive cantilevers to quantitatively evaluate bristled wing characteristics. Each cantilever had combs with varying widths and neighboring gaps that were adjusted so that a constant surface area was maintained. The cantilever body was 1,324 × 256 × 5 μm 3 in size. An aerodynamic drag force from the airflow applied to the cantilever surface was measured using the fractional resistance change of the piezoresistor due to the cantilever's deformation. The aerodynamic characteristics of each model were evaluated in a wind tunnel with airflow velocities between 1.2 and 5.6 m/s. The experimental results suggest that at a lower comb-width-based Reynolds number that was approximately equal to that of a bristled wing of a thrips, the comb areas of the cantilever act as an airflow suppression due to boundary layer effects, which results in an increased aerodynamic force.