Thermo-Optic Phase Shifter with Interleaved Suspended Design for Power Efficiency and Speed Adjustment.

Conventional thermo-optic devices-which can be broadly categorized to that with and without a thermal isolation trench-typically come with a tradeoff between thermal tuning efficiency and tuning speed. Here, we propose a method that allows us to directly define the tradeoff using a specially designed thermo-optic phase shifter with an interleaved isolation trench. With the design, the tuning efficiency and speed can be precisely tailored simply by controlling the duty ratio (suspended length over total heater length) of the suspended design. Phase shifters are one of the main components in photonic-integrated circuits, and having phase shifters with a flexible design approach may enable the wide adoption of photonic applications such as an optical neural network and LiDAR.

Food system resilience and COVID-19 - Lessons from the Asian experience.

The impact of the COVID-19 pandemic on the food system has exposed the vulnerabilities of the supply chain, although the extent of disruption varies widely, globally and in Asia. However, food systems in Asia have been proven relatively resilient when compared with other regions. This paper considers the immediate effects of the COVID-19 pandemic on the food system, particularly in Asia, and initial responses of governments and global agencies to manage the crisis. A major focus of the paper is on the outlook for food system resilience in a post-COVID-19 environment and likely long-term effects of the pandemic. There is always a possibility of such shock events occurring in the future, hence it seems prudent to look at lessons that may be learned from the responses to the current pandemic.

Small-scale variability in a mosaic tropical rainforest influences habitat use of long-tailed macaques.

Pristine habitats have generally been considered to be the most important ecological resource for wildlife conservation, but due to forest degradation caused by human activities, mosaics of secondary forests have become increasingly prominent. We studied three forest types in a mosaic tropical forest consisting of short secondary forest (SS), tall secondary forest (TS) and freshwater swamp forest (SF). These forests differed in stand structure and floristic composition, as well as phenological productivity of fruits, flowers and young leaves. We examined habitat use of long-tailed macaques (Macaca fascicularis) in relation to indices of phenological activity. The macaques used the SS for feeding/foraging more than the TS and the SF. This was because the SS had higher productivity of fruit, which is a preferred food resource for macaques. Stem densities of young leaves in the SS and the TS also influenced habitat use, as they provided more clumped resources. Use of SF was limited, but these forests provided more species-rich resources. Our results showed that M. fascicularis responded to small-scale variability in phenological activity between forest types found in a heterogeneous mosaic forest, with young secondary regrowth forests likely providing the most important food resources. Mosaic landscapes may be important as they can buffer the effects of temporal food resource variability in any given forest type. In our increasingly human-altered landscapes, a better understanding of the role of secondary forest mosaics is crucial to the conservation and management of wildlife habitats and the animals they support.

Toxic effect of high concentration of sonochemically synthesized polyvinylpyrrolidone-coated silver nanoparticles on Citrobacter sp. A1 and Enterococcus sp. C1.

BACKGROUND/PURPOSE: Currently, silver nanoparticles (AgNPs) have gained importance in various industrial applications. However, their impact upon release into the environment on microorganisms remains unclear. The aim of this study was to analyze the effect of polyvinylpyrrolidone-capped AgNPs synthesized in this laboratory on two bacterial strains isolated from the environment, Gram-negative Citrobacter sp. A1 and Gram-positive Enterococcus sp. C1. METHODS: Polyvinylpyrrolidone-capped AgNPs were synthesized by ultrasound-assisted chemical reduction. Characterization of the AgNPs involved UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. Citrobacter sp. A1 and Enterococcus sp. C1 were exposed to varying concentrations of AgNPs, and cell viability was determined. Scanning electron microscopy was performed to evaluate the morphological alteration of both species upon exposure to AgNPs at 1000 mg/L. RESULTS: The synthesized AgNPs were spherical in shape, with an average particle size of 15 nm. The AgNPs had different but prominent effects on either Citrobacter sp. A1 or Enterococcus sp. C1. At an AgNP concentration of 1000 mg/L, Citrobacter sp. A1 retained viability for 6 hours, while Enterococcus sp. C1 retained viability only for 3 hours. Citrobacter sp. A1 appeared to be more resistant to AgNPs than Enterococcus sp. C1. The cell wall of both strains was found to be morphologically altered at that concentration. CONCLUSION: Minute and spherical AgNPs significantly affected the viability of the two bacterial strains selected from the environment. Enterococcus sp. C1 was more vulnerable to AgNPs, probably due to its cell wall architecture and the absence of silver resistance-related genes.

Ertapenem for treatment of extended-spectrum beta-lactamase-producing and multidrug-resistant gram-negative bacteraemia.

INTRODUCTION: Imipenem and meropenem are treatment of choice for extended-spectrum betalactamase (ESBL)-positive gram-negative bacteraemia. They may select for carbapenemresistant Acinetobacter baumannii and Pseudomonas aeruginosa; ertapenem may not do so as it is inactive against these bacteria. Clinical efficacy of ertapenem in ESBL-producing gramnegative bacteraemia is limited. MATERIALS AND METHODS: Retrospective study of patients with ESBL-positive gram-negative bacteraemia treated with ertapenem was undertaken. RESULTS: Forty-seven patients with multidrug-resistant gram-negative bacteraemia (79% produced ESBL) were treated with ertapenem for a median duration of 11 days. The median age was 70 years. Septic shock occurred in 19% and mechanical ventilation was needed in 17%. Klebsiella pneumoniae comprised 53% and Escherichia coli 26%. Urinary infection accounted for 61% and hepatobiliary 15%. Favourable clinical response occurred in 96%. Attributable mortality was 4%. CONCLUSION: Ertapenem is promising in culture-guided step-down therapy of ESBL-positive gram-negative bacteraemia.

Identification of IRF6 gene variants in three families with Van der Woude syndrome.

Van der Woude syndrome is the most common cause of syndromic orofacial clefting. It is characterised by the presence of lip pits, cleft lip and/or cleft palate. It is transmitted in an autosomal dominant manner, with high penetrance and variable expressivity. Several mutations in the interferon regulatory factor 6 (IRF6) gene have been found in VWS families, suggesting that this gene is the primary locus. We screened for mutations in this gene in three families in our population. There was a recurrent nonsense mutation within exon 9 of the gene for a Malay family consisting of five affected members with different presentations. We also found a co-segregating rare polymorphism which would result in a non-synonymous change 23 bases downstream of the nonsense mutation. This polymorphism was present in <1% of the Malay subjects screened, but was not found among the Chinese and Indians in our population. For another family, a 396C-->T mutation (R45W in the DNA-binding domain) was found in the proband, although the possibility of a genetic defect elsewhere could not be excluded because his mother and twin sister (both unaffected) also had this variant. In the third case with complete absence of family history, a de novo deletion spanning the whole IRF6 gene was detected in the child with VWS. This case of haploinsufficiency caused disruption of orofacial development but not other organ systems as the child has no other medical or developmental abnormalities despite the deletion of at least five other genes.

Ertapenem for treatment of extended-spectrum beta-lactamase-producing and multidrug-resistant gram-negative bacteraemia

<p><b>INTRODUCTION</b>Imipenem and meropenem are treatment of choice for extended-spectrum betalactamase (ESBL)-positive gram-negative bacteraemia. They may select for carbapenemresistant Acinetobacter baumannii and Pseudomonas aeruginosa; ertapenem may not do so as it is inactive against these bacteria. Clinical efficacy of ertapenem in ESBL-producing gramnegative bacteraemia is limited.</p><p><b>MATERIALS AND METHODS</b>Retrospective study of patients with ESBL-positive gram-negative bacteraemia treated with ertapenem was undertaken.</p><p><b>RESULTS</b>Forty-seven patients with multidrug-resistant gram-negative bacteraemia (79% produced ESBL) were treated with ertapenem for a median duration of 11 days. The median age was 70 years. Septic shock occurred in 19% and mechanical ventilation was needed in 17%. Klebsiella pneumoniae comprised 53% and Escherichia coli 26%. Urinary infection accounted for 61% and hepatobiliary 15%. Favourable clinical response occurred in 96%. Attributable mortality was 4%.</p><p><b>CONCLUSION</b>Ertapenem is promising in culture-guided step-down therapy of ESBL-positive gram-negative bacteraemia.</p>

Gender-specific association of insertion/deletion polymorphisms in the nogo gene and chronic schizophrenia.

Nogo is a myelin-associated protein associated with neurite outgrowth and regeneration. A previous study has reported an association between an insertion/deletion polymorphism in schizophrenia. We tested for the distribution of the polymorphism and haplotypes of this and another insertion/deletion polymorphism in our population. We have also developed an assay combining allele-specific polymerase chain reaction (AS-PCR) and restriction fragment length polymorphism (RFLP) to simultaneously type these two insertion/deletion polymorphisms. There was a statistically significant difference at the allelic level for both the CAA (chi2 = 4.378, df = 1, P value = 0.036) and TATC (chi2 = 5.807, df = 1, P = 0.016) polymorphisms in the female subgroup, but not in males. With our genotyping method, we also determined the molecular haplotype. Within the female gender, odds ratio is at 1.57 (95% CI 1.05-2.37) for CAACAA-TATC and 1.40 (95% CI 0.55-3.60) for CAA-TATC, the two at-risk haplotypes. Odds ratio is 0.63 (95% CI 0.42-0.93) for the protective wildtype haplotype CAA-TATCTATC. Further study of these two polymorphisms to investigate functional significance and confirm gender-specific association should be carried out.

Genomic and phylogenetic analysis of the S100A7 (Psoriasin) gene duplications within the region of the S100 gene cluster on human chromosome 1q21.

The human S100 gene family encodes the EF-hand superfamily of calcium-binding proteins, with at least 14 family members clustered relatively closely together on chromosome 1q21. We have analyzed the most recently available genomic sequence of the human S100 gene cluster for evidence of tandem gene duplications during primate evolutionary history. The sequences obtained from both GenBank and GoldenPath were analyzed in detail using various comparative sequence analysis tools. We found that of the S100A genes clustered relatively closely together within a genomic region of 260 kb, only the S100A7 (psoriasin) gene region showed evidence of recent duplications. The S100A7 gene duplicated region is composed of three distinct genomic regions, 33, 11, and 31 kb, respectively, that together harbor at least five identifiable S100A7-like genes. Regions 1 and 3 are in opposite orientation to each other, but each region carries two S100A7-like genes separated by an 11-kb intergenic region (region 2) that has only one S100A7-like gene, providing limited sequence resemblance to regions 1 and 3. The duplicated genomic regions 1 and 3 share a number of different retroelements including five Alu subfamily members that serve as molecular clocks. The shared (paralogous) Alu S insertions suggest that regions 1 and 3 were probably duplicated during or after the phase of AluS amplification some 30-40 mya. We used PCR to amplify an indel within intron 1 of the S100A7a and S100A7c genes that gave the same two expected product sizes using 40 human DNA samples and 1 chimpanzee sample, therefore confirming the presence of the region 1 and 3 duplication in these species. Comparative genomic analysis of the other S100 gene members shows no similarity between intergenic regions, suggesting that they diverged long before the emergence of the primates. This view was supported by the phylogenetic analysis of different human S100 proteins including the human S100A7 protein members. The S100A7 protein, also known as psoriasin, has important functions as a mediator and regulator in skin differentiation and disease (psoriasis), in breast cancer, and as a chemotactic factor for inflammatory cells. This is the first report of five copies of the S100A7 gene in the human genome, which may impact on our understanding of the possible dose effects of these genes in inflammation and normal skin development and pathogenesis.