Ultrafast all-optical switching via coherent modulation of metamaterial absorption

We report on the demonstration of a femtosecond all-optical modulator providing, without nonlinearity and therefore at arbitrarily low intensity, ultrafast light-by-light control. The device engages the coherent interaction of optical waves on a metamaterial nanostructure only 30 nm thick to efficiently control absorption of near-infrared (750-1040 nm) femtosecond pulses, providing switching contrast ratios approaching 3:1 with a modulation bandwidth in excess of 2 THz. The functional paradigm illustrated here opens the path to a family of novel meta-devices for ultra-fast optical data processing in coherent networks.Comment: 5 pages, 4 figure

English, Arabic, and Chinese Loanwords in Brunei Malay

Brunei Malay is a unique Malay dialect spoken not only in Brunei Darussalam, but also in neighboring parts of Borneo. Although extensive data are available on lexical borrowings in Standard Malay and Indonesian, surprisingly, Brunei Malay has not been studied in this regard. Our paper aims to fill this gap by identifying English, Arabic and Chinese loanwords in the only available dictionary (Kamus Bahasa Melayu Brunei). We had looked into the linguistic distribution and word classes of the borrowed lexis, and understood that the main borrower was Arabic, followed by English; however, only a few words of Chinese origin could be found in the corpus. The most prominent word class was nouns, with a significantly lower number of verbs and adjectives. In the last part of our paper we are going to give some examples for usage of these loanwords in context

Phytochemical Analysis of Some Celery Accessions

The essential oil, phenolic acids, and other constituents in three accessions of celery (Apium graveolens L) were investigated to determine phytochemical variability that lead to differences in yield and phytochemical profiles. The celery accessions were all grown in pots under the same environmental conditions. Analyses were done on two planting of three harvests each to determine and compare the levels of anthocyanin, carotenoids, chlorophyll, phenolic acids, rosmarinic acid, soluble sugars, tannins, and essential oil content. Except for carotenoids, significant variations in the phytochemical profiles among the three celery accessions were observed

Efficient and direct estimation of the variance–covariance matrix in EM algorithm with interpolation method

The expectation–maximization (EM) algorithm is a seminal method to calculate the maximum likelihood estimators (MLEs) for incomplete data. However, one drawback of this algorithm is that the asymptotic variance–covariance matrix of the MLE is not automatically produced. Although there are several methods proposed to resolve this drawback, limitations exist for these methods. In this paper, we propose an innovative interpolation procedure to directly estimate the asymptotic variance–covariance matrix of the MLE obtained by the EM algorithm. Specifically we make use of the cubic spline interpolation to approximate the first-order and the second-order derivative functions in the Jacobian and Hessian matrices from the EM algorithm. It does not require iterative procedures as in other previously proposed numerical methods, so it is computationally efficient and direct. We derive the truncation error bounds of the functions theoretically and show that the truncation error diminishes to zero as the mesh size approaches zero. The optimal mesh size is derived as well by minimizing the global error. The accuracy and the complexity of the novel method is compared with those of the well-known SEM method. Two numerical examples and a real data are used to illustrate the accuracy and stability of this novel method.The National Research Foundation of South Africa and the South African Medical Research Council (SAMRC).http://www.elsevier.com/locate/jspihj2022Statistic

Special issue on advances in fractional dynamics in mechanical engineering

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On unsteady two-dimensional and axisymmetric squeezing flow between parallel plates

AbstractSqueezing flow of a viscous fluid is considered. Two types of flows are discussed namely, the axisymmetric flow and two dimensional flow. Similarity transform proposed by Wang (1976) [13] has been used to reduce the Navier–Stokes equations to a highly non-linear ordinary differential equation which jointly describes both types of flows. Solution to aforementioned ordinary differential equation is obtained by using Variation of Parameters Method (VPM). VPM is free from the existence of small or large parameters and hence it can be applied to a large variety of problems as compared to the perturbation method applied by Wang (1976) [13]. Comparison among present and already existing solutions is also provided to show the efficiency of VPM. A convergence analysis is also carried out. Effects of different physical parameters on the flow field is discussed and demonstrated graphically with comprehensive discussions and explanations

A case of Bickerstaff's brainstem encephalitis in childhood

Bickerstaff&apos&#59;s brainstem encephalitis (BBE) is a rare disease diagnosed by specific clinical features such as &apos&#59;progressive, relatively symmetric external ophthalmoplegia and ataxia by 4 weeks&apos&#59; and &apos&#59;disturbance of consciousness or hyperreflexia&apos&#59; after the exclusion of other diseases involving the brain stem. Anti-ganglioside antibodies (GM, GD and GQ) in the serum or cerebrospinal fluid (CSF) are sometimes informative for the diagnosis of BBE because of the rarity of positive findings in other diagnositic methods: brain magnetic resonance imaging (MRI), routine CSF examination, motor nerve conduction study, and needle electromyography. We report a rare case of childhood BBE with elevated anti-GM1 antibodies in the serum, who had specific clinical symptoms such as a cranial polyneuropathy presenting as ophthalmoplegia, dysarthria, dysphagia, and facial weakness&#59; progressive motor weakness&#59; altered mental status&#59; and ataxia. However, the brain MRI, routine CSF examination, nerve conduction studies, electromyography, somatosensory evoked potentials, and brainstem auditory evoked potentials were normal. BBE was suspected and the patient was successfully treated with intravenous immunoglobulins

Mismatch Repair proteins are recruited to replicating DNA through interaction with Proliferating Cell Nuclear Antigen (PCNA)

Mismatch Repair (MMR) is closely linked to DNA replication; however, other than the role of the replicative sliding clamp (PCNA) in various MMR functions, the linkage between DNA replication and MMR has been difficult to investigate. Here we use an in vitro DNA replication system based on simian virus 40, to investigate MMR recruitment to replicating DNA. Both DNA replication and MMR proteins are recruited to replicating DNA in an origin-dependent fashion. Primer synthesis is required for recruitment of both PCNA and MMR proteins, but not for recruitment of the single-stranded DNA-binding protein (RPA). Blocking PCNA recruitment to replicating DNA with a p21-based polypeptide blocks PCNA and MMR, but not RPA recruitment. Once PCNA and subsequent proteins required for replication are loaded onto DNA, addition of p21 leaves PCNA on the replicating DNA, but actively displaces MMR proteins. These findings indicate that the MMR machinery is recruited to replicating DNA through its interaction with PCNA, and suggests that this occurs via binding of the MMR proteins to the multi-protein interaction sites on PCNA. These studies demonstrate the utility of this system for further investigation of the role of DNA replication in MMR

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Different Chitin Synthase Genes Are Required for Various Developmental and Plant Infection Processes in the Rice Blast Fungus Magnaporthe oryzae

Chitin is a major component of fungal cell wall and is synthesized by chitin synthases (Chs). Plant pathogenic fungi normally have multiple chitin synthase genes. To determine their roles in development and pathogenesis, we functionally characterized all seven CHS genes in Magnaporthe oryzae. Three of them, CHS1, CHS6, and CHS7, were found to be important for plant infection. While the chs6 mutant was non-pathogenic, the chs1 and chs7 mutants were significantly reduced in virulence. CHS1 plays a specific role in conidiogenesis, an essential step for natural infection cycle. Most of chs1 conidia had no septum and spore tip mucilage. The chs6 mutant was reduced in hyphal growth and conidiation. It failed to penetrate and grow invasively in plant cells. The two MMD-containing chitin synthase genes, CHS5 and CHS6, have a similar expression pattern. Although deletion of CHS5 had no detectable phenotype, the chs5 chs6 double mutant had more severe defects than the chs6 mutant, indicating that they may have overlapping functions in maintaining polarized growth in vegetative and invasive hyphae. Unlike the other CHS genes, CHS7 has a unique function in appressorium formation. Although it was blocked in appressorium formation by germ tubes on artificial hydrophobic surfaces, the chs7 mutant still produced melanized appressoria by hyphal tips or on plant surfaces, indicating that chitin synthase genes have distinct impacts on appressorium formation by hyphal tip and germ tube. The chs7 mutant also was defective in appressorium penetration and invasive growth. Overall, our results indicate that individual CHS genes play diverse roles in hyphal growth, conidiogenesis, appressorium development, and pathogenesis in M. oryzae, and provided potential new leads in the control of this devastating pathogen by targeting specific chitin synthases