Objectives: Following a cluster of COVID-19 cases in a Singapore public hospital in April 2021, the local health authority mandated the use of N95 respirators in all inpatient wards. This increased the demand for N95 mask fit-testing to ensure that healthcare workers were donning respirators that fit their facial characteristics and hence provided protection through a good facial seal. The demand for fit-testing during the pandemic highlighted the scarcity of manpower and ergonomics concern, such as carpel tunnel syndrome experienced in long hours of qualitative fit-testing sessions. We evaluated the operational efficiency, cost-effectiveness, and difference in passing rate after the introduction of the quantitative method. Methods: Conventional qualitative fit-testing was conducted using manual pumping of a challenge agent, enabling the user to determine the fit of the respirator. The quantitative fit-testing protocol used a condensation particle counter (CPC) to measure the concentration of particles inside the mask and the atmosphere to determine the fit of respirator. The Occupational Safety and Health Administration (OSHA)–approved minimum fit factor of 100 was used as the criterion for a successful N95 respirator fit. Tubes used during quantitative fit-testing were reprocessed using thermal disinfection. Results: Quantitative mask fit-testing provided an objective numerical measure to assess adequate fit of N95 respirator, which provided users with confidence in the respirator fit. It addressed a manpower limitation issue because it did not require qualified trainers to conduct the test, and automation also prevented any potential occupational hazard from repeated actions required in qualitative fit-testing. An increase in the passing rate for N95 fit-testing from 94.5% to 95.5% was observed. However, the high cost of equipment, annual recalibration, and consumables must be considered. Conclusions: Quantitative N95 fit-testing, when adopted with careful consideration of its cost, is an approach to consider for hospital-wide fit-testing.

Objectives: In response to the COVID-19 pandemic, primary care swiftly transformed and re-established patient flow in clinics to red, orange, and green zones based on a set of screening criteria. To further manage the influx of suspected COVID-19 patients and their needs safely, a list of surveillance audit criteria was developed to ensure good infection control standards. Methods: The infection control team prepared the surveillance audit criteria based on recommended CDC/WHO guidelines for pandemic preparedness. These criteria were contextualized to the primary-care polyclinic setting. The surveillance audit criteria were grouped according to their category: screening, triage, early recognition and source control, inventory management of personal protective equipment (PPE), infection control measures in the red zone, precautionary measures during collection of nasopharyngeal swabs and environmental cleaning and disinfection for premises in the red, orange, and green zones, respectively. The infection control liaison nurses in each polyclinic were trained to use the checklist to ensure consistency in interpretation of the criteria. Results: Surveillance audits were conducted biweekly in the first 3 months then monthly once the compliance rate was steady at 90%–100% for all categories. The overall average compliance rate since commencing in March 2020 for all polyclinics was sustained at 90%–100%. Common findings included inappropriate use of PPE (eg, self-contamination during removal of gown or wrong sequence of doffing), inadequate ventilation, and inadequate cleaning processes. All findings were corrected immediately, and staff education was provided. Conclusions: Primary care plays an important role during a pandemic. It is essential that both patients and healthcare workers in the primary care setting are protected from infection risk during a pandemic. Having a good surveillance audit process helps ensure that primary care services can continue for the general population. Surveillance is an essential component of the health system’s response to a pandemic.

We prove the existence of unbounded solutions of the asymmetric oscillation in the case when each zero of the discriminative function is degenerate. This is the only case that has not been studied in the literature.

As the interface between plants and the environment, the leaf epidermis provides the first layer of protection against drought, ultraviolet light, and pathogen attack. This cell layer comprises highly coordinated and specialised cells such as stomata, pavement cells and trichomes. While much has been learned from the genetic dissection of stomatal, trichome and pavement cell formation, emerging methods in quantitative measurements that monitor cellular or tissue dynamics will allow us to further investigate cell state transitions and fate determination in leaf epidermal development. In this review, we introduce the formation of epidermal cell types in Arabidopsis and provide examples of quantitative tools to describe phenotypes in leaf research. We further focus on cellular factors involved in triggering cell fates and their quantitative measurements in mechanistic studies and biological patterning. A comprehensive understanding of how a functional leaf epidermis develops will advance the breeding of crops with improved stress tolerance.

The influence of second-order dispersion (SOD) on stimulated Raman scattering (SRS) in the interaction of an ultrashort intense laser with plasma was investigated. More significant backward SRS was observed with the increase of the absolute value of SOD ($\mid \kern-1pt\!{\psi}_2\!\kern-1pt\mid$). The integrated intensity of the scattered light is positively correlated to the driver laser pulse duration. Accompanied by the side SRS, filaments with different angles along the laser propagation direction were observed in the transverse shadowgraph. A model incorporating Landau damping and above-threshold ionization was developed to explain the SOD-dependent angular distribution of the filaments.

An experimental investigation of the stereocamera's systematic error is carried out to optimize three-dimensional (3-D) dust observation on the HL-2A tokamak. It is found that a larger 3-D region occupied by all calibration points is able to reduce the 3-D reconstruction systematic error of the stereocamera. In addition, the 3-D reconstruction is the most accurate around the region where the calibration points are located. Based on these experimental results, the design of the stereocamera on the HL-2A tokamak is presented, and a set of practical procedures to optimize the 3-D reconstruction accuracy of the stereocamera are proposed.

This paper revisits the melting process of phase change materials (PCMs) enclosed in a horizontally placed rectangular cavity, with isothermal and adiabatic conditions subjected to the vertical and horizontal walls, respectively. First, numerical simulations based on an improved lattice Boltzmann method are conducted to illustrate and to inform the theoretical modelling. It is shown that, compared with the traditional two-stage conduction–convection melting description, it is more reasonable to include a third stage in terms of the heat transfer behaviour. During the third stage, the remnant solid PCM is located in the corner formed by the cold and bottom walls of the cavity, and an increasing part of the input energy will be transferred directly out of the cavity without compensating for the melting latent heat, thus inducing a continuously decreasing melting rate until the end of the melting process. Then theoretical predictions are derived piecewise for the melted liquid fraction during the entire melting process, and the corresponding transitions between two successive stages are also discussed. The results are validated successfully via the available experimental and numerical data in the literature, and could guide the design and operation of latent heat storage systems.

Previous studies have reported inconsistent associations between low-carbohydrate diets (LCD) and plasma lipid profile. Also, there is little evidence on the role of the quality and food sources of macronutrients in LCD in cardiometabolic health. We investigated the cross-sectional associations between LCD and plasma cardiometabolic risk markers in a nationwide representative sample of the US population. Diet was measured through two 24-h recalls. Overall, healthy (emphasising unsaturated fat, plant protein and less low-quality carbohydrates) and unhealthy (emphasising saturated fat, animal protein and less high-quality carbohydrate) LCD scores were developed according to the percentage of energy as total and subtypes of carbohydrate, protein and fat. Linear regression was used to estimate the percentage difference of plasma marker concentrations by LCD scores. A total of 34 785 participants aged 18–85 years were included. After adjusting for covariates including BMI, healthy LCD was associated with lower levels of insulin, homoeostatic model assessment for insulin resistance (HOMA-IR), C-reactive protein (CRP) and TAG, and higher levels of HDL-cholesterol, with the percentage differences (comparing extreme quartile of LCD score) of −5·91, −6·16, −9·13, −9·71 and 7·60 (all P trend < 0·001), respectively. Conversely, unhealthy LCD was associated with higher levels of insulin, HOMA-IR, CRP and LDL-cholesterol (all P trend < 0·001). Our results suggest that healthy LCD may have positive, whereas unhealthy LCD may have negative impacts on CRP and metabolic and lipid profiles. These findings underscore the need to carefully consider the quality and subtypes of macronutrients in future LCD studies.

Let N be a sufficiently large integer. We prove that, with at most $O(N^{23/48+\varepsilon })$ exceptions, all even positive integers up to N can be represented in the form $p_1^2+p_2^3+p_3^3+p_4^3+p_5^3+p_6^4$ , where $p_1,p_2,p_3,p_4,p_5,p_6$ are prime numbers.

Pharmacological treatment of major depressive disorder is often inefficient, and multiple strategies are used for inadequate response to antidepressants. Second-generation antipsychotics are used as augmentation measures in clinical practice; evidence of their efficacy and acceptability is insufficient, and it remains confusing as to which drug should be selected first. In this systematic review and network meta-analysis, we included randomised controlled trials of second-generation antipsychotics used as adjunctive treatment in patients with suboptimal responses. Outcome measures were efficacy (response and remission) and acceptability (dropout due to any reason and adverse events). Thirty-three trials comprising 10 602 participants were included. Regarding efficacy, response rates indicated that all antipsychotics except for ziprasidone were more efficacious than the placebo, with the odds ratios (ORs) ranging from 1.34 for olanzapine and cariprazine [95% credible interval (CrI) 1.04–1.73 and 1.07–1.67, respectively] to 2.17 for risperidone (95% CrI 1.38–3.42). When considering remission, cariprazine was not effective (OR 1.21, 95% CrI 0.96–1.54). For acceptability, quetiapine (OR 0.68, 95% CrI 0.50–0.91), brexpiprazole (OR 0.69, 95% CrI 0.55–0.86), and cariprazine (OR 0.61, 95% CrI 0.46–0.82) were worse than the placebo. With regards to tolerability, only olanzapine (OR 0.51, 95% CrI 0.25–1.07) and risperidone (OR 0.48, 95% CrI 0.10–2.21) showed no significant differences compared with placebo. The administration of adjunctive antipsychotics is associated with high effectiveness and low acceptability. Risperidone and aripiprazole are more efficacious and accepted than other atypical antipsychotics.

Severe heat exposure causes mitochondrial fragmentation and dysfunction, which contribute to the pathogenesis of heat-related illness. l-Citrulline is a naturally occurring amino acid and has been suggested to influence heat shock responses. This study aimed to test whether l-citrulline supplementation would preserve mitochondrial integrity and attenuate heat-induced skeletal muscle injury and elucidate the underlying mechanisms. At 37°C, l-citrulline (2 mM) increased mitochondrial elongation in mouse C2C12 myoblasts, a process associated with a reduction in mitochondrial fission protein Drp1 levels. Mechanistic studies revealed that l-citrulline increased cellular nitric oxide (NO) levels, but not S-nitrosylation of Drp1. l-Citrulline caused a decrease in phosphorylation of Drp1 at Ser 616 and an increase in phosphorylation of Drp1 at Ser 637, which resulted in a reduced mitochondrial localisation of Drp1. L-NAME, a non-selective NO synthase inhibitor, abolished the increase in l-citrulline-induced NO levels and inhibited Drp1 phosphorylation changes and mitochondrial elongation, which indicates the involvement of a NO-dependent pathway. Under 43°C heat stress conditions, l-citrulline prevented translocation of Drp1 to mitochondria, mitochondrial fragmentation and decreased membrane potential. Finally, l-citrulline pretreatment inhibited heat-induced reactive oxygen species overproduction, caspase 3/7 activation, apoptotic cell death and improved cell viability. NO inhibitor l-NAME abolished all the above protective effects of l-citrulline under heat stress. Our results suggest that l-citrulline prevents heat-induced mitochondrial dysfunction and cell injury through NO-mediated Drp1 inhibition in C2C12 myoblasts. l-Citrulline may be an effective treatment for heat-related illnesses and other mitochondrial diseases.

Pregnancy is a complex biological process. The establishment and maintenance of foetal–maternal interface are pivotal events. Decidual immune cells and inflammatory cytokines play indispensable roles in the foetal–maternal interface. The disfunction of decidual immune cells leads to adverse pregnancy outcome. Tumour necrosis factor (TNF)-α, a common inflammatory cytokine, has critical roles in different stages of normal pregnancy process. However, the relationship between the disorder of TNF-α and adverse pregnancy outcomes, including preeclampsia (PE), intrauterine growth restriction (IUGR), spontaneous abortion (SA), preterm birth and so on, is still indefinite. In this review, we thoroughly reviewed the effect of TNF-α disorder on pathological conditions. Moreover, we summarized the reports about the adverse pregnancy outcomes (PE, IUGR, SA and preterm birth) of using anti-TNF-α drugs (infliximab, etanercept and adalimumab, certolizumab and golimumab) currently in the clinical studies. Overall, IUGR, SA and preterm birth are the most common adverse pregnancy outcomes of anti-TNF-α drugs. Our review may provide insight for the immunological treatment of pregnancy-related complication, and help practitioners make informed decisions based on the current evidences.

Dietary l-carnitine (LC) is a nutritional factor that reduces liver lipid content. However, whether dietary LC can improve lipid metabolism via simultaneous activation of mitochondrial fatty acid (FA) β-oxidation and suppression of endoplasmic reticulum (ER) stress is still unknown. Large yellow croaker were fed with a high-fat diet (HFD) supplemented with dietary LC at 0, 1·2 or 2·4 ‰ for 10 weeks. The results indicated that a HFD supplemented with LC reduced the liver total lipid and TAG content and improved serum lipid profiles. LC supplementation administered to this fish increased the liver antioxidant capacity by decreasing serum and liver malondialdehyde levels and enhancing the liver antioxidant capacity, which then relieved the liver damage. Dietary LC increased the ATP dynamic process and mitochondrial number, decreased mitochondrial DNA damage and enhanced the protein expression of mitochondrial β-oxidation, biogenesis and mitophagy. Furthermore, dietary LC supplementation increased the expression of genes and proteins related to peroxisomal β-oxidation and biogenesis. Interestingly, feeding fish with LC-enriched diets decreased the protein levels indicative of ER stress, such as glucose-regulated protein 78, p-eukaryotic translational initiation factor 2a and activating transcription factor 6. Dietary LC supplementation downregulated mRNA expression relative to FA synthesis, reduced liver lipid and relieved liver damage through regulating β-oxidation and biogenesis of mitochondria and peroxisomes, as well as the ER stress pathway in fish fed with HFD. The present study provides the first evidence that dietary LC can improve lipid metabolism via simultaneously promoting FA β-oxidation capability and suppressing the ER stress pathway in fish.