Melanin, a black-brown pigment found throughout all kingdoms of life, has diverse biological functions including UV protection, thermoregulation, oxidant scavenging, arthropod immunity, and microbial ...virulence. Given melanin's broad roles in the biosphere, particularly in insect immune defenses, it is important to understand how exposure to ubiquitous environmental contaminants affects melanization. Glyphosate-the most widely used herbicide globally-inhibits melanin production, which could have wide-ranging implications in the health of many organisms, including insects. Here, we demonstrate that glyphosate has deleterious effects on insect health in 2 evolutionary distant species, Galleria mellonella (Lepidoptera: Pyralidae) and Anopheles gambiae (Diptera: Culicidae), suggesting a broad effect in insects. Glyphosate reduced survival of G. mellonella caterpillars following infection with the fungus Cryptococcus neoformans and decreased the size of melanized nodules formed in hemolymph, which normally help eliminate infection. Glyphosate also increased the burden of the malaria-causing parasite Plasmodium falciparum in A. gambiae mosquitoes, altered uninfected mosquito survival, and perturbed the microbial composition of adult mosquito midguts. Our results show that glyphosate's mechanism of melanin inhibition involves antioxidant synergy and disruption of the reaction oxidation-reduction balance. Overall, these findings suggest that glyphosate's environmental accumulation could render insects more susceptible to microbial pathogens due to melanin inhibition, immune impairment, and perturbations in microbiota composition, potentially contributing to declines in insect populations.
Summary
Background
Tinea capitis is still common in developing countries, such as China. Its pathogen spectrum varies across regions and changes over time.
Objectives
This study aimed to clarify the ...current epidemiological characteristics and pathogen spectrum of tinea capitis in China.
Methods
A multicentre, prospective descriptive study involving 29 tertiary hospitals in China was conducted. From August 2019 to July 2020, 611 patients with tinea capitis were enrolled. Data concerning demography, risk factors and fungal tests were collected. When necessary, the pathogens were further identified by morphology or molecular sequencing in the central laboratory.
Results
Among all enrolled patients, 74·1% of the cases were in patients aged 2–8 years. The children with tinea capitis were mainly boys (56·2%) and were more likely than adults to have a history of animal contact (57·4% vs. 35·3%, P = 0·012) and zoophilic dermatophyte infection (73·5% vs. 47%). The adults were mainly female (83%) and were more likely than children to have anthropophilic agent infection (53% vs. 23·9%). The most common pathogen was zoophilic Microsporum canis (354, 65·2%), followed by anthropophilic Trichophyton violaceum (74, 13·6%). In contrast to the eastern, western and northeastern regions, where zoophilic M. canis predominated, anthropophilic T. violaceum predominated in central China (69%, P < 0·001), where the patients had the most tinea at other sites (20%) and dermatophytosis contact (26%) but the least animal contact (39%). Microsporum ferrugineum was the most common anthropophilic agent in the western area, especially in Xinjiang province.
Conclusions
Boys aged approximately 5 years were the most commonly affected group. Dermatologists are advised to pay more attention to the different transmission routes and pathogen spectra in different age groups from different regions.
What is already known about this topic?
Tinea capitis is an infection of the scalp and hair caused by dermatophytes and is still common in developing countries. Prepubertal children are mainly affected.
The pathogen spectrum of tinea capitis varies across different geographical areas and changes over time.
Nationwide prospective epidemiological surveys of tinea capitis in China are rare and out of date.
What does this study add?
This study provides data concerning the epidemiological characteristics and pathogen spectrum of tinea capitis in contemporary China.
Boys aged approximately 5 years were most commonly affected and were more likely than adults to have zoophilic dermatophyte infection.
The main pathogens of tinea capitis in China are zoophilic dermatophytes, mainly Microsporum canis. In contrast to the other regions, the predominant pathogens in central China are anthropophilic dermatophytes.
Plain language summary available online
•A measuring method of discharge coefficient of each nozzle hole was proposed.•The differences in discharge coefficient of each nozzle hole were primarily studied.•Two effects on transient discharge ...coefficient of each nozzle hole were analyzed.
The objective of this paper is to propose a measuring method based on the spray momentum flux measurement of each nozzle hole that could be used to determine the transient discharge coefficient of each nozzle hole of a multi-hole diesel injector. For this purpose, a measurement system for the transient discharge coefficient of each nozzle hole was established utilizing a conventional injection system of pump-line-nozzle and a dedicated constructed experimental rig. By measuring the spray momentum flux of each nozzle hole of the multi-hole fuel injector and injection pressure of the pump-pipe-injector fuel delivery system, the discharge coefficient of each nozzle hole was obtained, and analyzed throughout the injection duration and with different injection pump speeds and cycle fuel injection quantities. The results show that the transient discharge coefficient of each nozzle hole changes constantly, meanwhile, the variations of the transient discharge coefficient of the nozzle holes were similar. However, the discharge coefficient of the nozzle holes were not uniform at the same operating condition and that of the No.5 was apparently lower than that of the others. With increasing cam speed, the fluctuations of the discharge coefficients were variably stable at the maximum needle position.The fluctuations of the discharge coefficients of the nozzle holes were higher for the smaller cycle fuel injection quantity, but as the fluctuation gradually became smaller, the mean discharge coefficient of each nozzle hole increased slightly with increasing cycle fuel injection quantity.
Objective
To investigate the clinical outcome and endocrinological characteristics of progestin‐primed ovarian stimulation (PPOS) using 4 versus 10 mg of medroxyprogesterone acetate (MPA) per day in ...infertile women with normal ovary reserve.
Design
A randomised parallel controlled trial.
Setting
Tertiary‐care academic medical centre.
Participants
A cohort of 300 infertile women undergoing in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) treatment.
Methods
Human menopausal gonadotropin (hMG; 225 iu per day) and MPA (group A, 10 mg per day; group B, 4 mg per day) were started simultaneously from cycle day 3 onwards. Ovulation was co‐triggered by human chorionic gonadotropin (hCG; 1000 iu) and gonadotropin‐releasing hormone agonist (GnRH agonist; 0.1 mg) when dominant follicles matured. Viable embryos were cryopreserved for later frozen embryo transfer (FET) in both groups.
Main outcome measures
The primary outcome measure was the number of oocytes retrieved. Secondary outcomes included the incidence of a premature surge in luteinising hormone (LH), the number of viable embryos, and clinical pregnancy outcomes.
Results
The number of oocytes retrieved and viable embryos were similar between two groups (9.8 ± 6.3 versus 9.6 ± 5.9; 4.2 ± 2.6 versus 3.7 ± 3.0; P > 0.05). No significant difference was found in clinical pregnancy rate (58.0 versus 48.7%) and live birth rate per participant (48.7 versus 42.0%; P > 0.05). No premature LH surge and ovarian hyperstimulation syndrome (OHSS) occurred in either group.
Conclusions
Progestin‐primed ovarian stimulation (PPOS) using 4 or 10 mg of MPA per day was comparable in terms of the number of oocytes retrieved and pregnancy outcome after FET. The administration of 4 mg of MPA per day was sufficient to prevent an untimely LH rise in women undergoing IVF/ICSI treatment.
Tweetable
An RCT confirmed similar pregnancy outcome in P‐primed ovarian stimulation with a daily dose of 4 or 10 mg MPA.
Tweetable
An RCT confirmed similar pregnancy outcome in P‐primed ovarian stimulation with a daily dose of 4 or 10 mg MPA.
Screw feeders are widely used in various industries to transfer granular materials at relatively precise rates. The performance can be affected by many factors such as the shape and size of ...particles, and the design of a screw and associated charging container. Some of these factors are difficult to investigate experimentally, including, for example, the cohesion between particles. In this work, a numerical model is developed by means of the discrete element method to study the flow of cohesive particles in screw feeders. In the model, the magnitude of the cohesive force is assumed, but it can be related to the van der Waals attraction for fine particles or the capillary force for wet particles. Based on the simulated results, a correlation for the prediction of solid flowrate is formulated as a function of the magnitude of cohesive force and the rotational speed of a screw. The mechanisms are then depicted in terms of contact forces and their spatial and temporal distributions. Three flow regimes, namely, continuous, intermittent and stable arch, are identified based on the standard deviation of solid flowrate in a screw feeder. Possible methods to reduce the effect of cohesive force on solid flow are discussed, in the study of the effects of the screw length in the associated charging container as well as the container design. The findings should be useful for the design and operation of screw feeders.
Different flow regimes of cohesive solid flow in screw feeders are observed, and the underlying mechanism is investigated. Display omitted
•Interparticle cohesion significantly affects solid flow in screw feeders.•Three flow regimes of cohesive particles in a screw feeder are identified.•The mechanism underlying the effect of interparticle cohesion is depicted.•The effects of some factors are quantified based on the DEM simulation.•Methods to reduce the effect of interparticle cohesion are discussed.
We report on the discovery and analysis of bursts from nine new repeating fast radio burst (FRB) sources found using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. These ...sources span a dispersion measure (DM) range of 195-1380 pc cm−3. We detect two bursts from three of the new sources, three bursts from four of the new sources, four bursts from one new source, and five bursts from one new source. We determine sky coordinates of all sources with uncertainties of ∼10′. We detect Faraday rotation measures (RMs) for two sources, with values −20(1) and −499.8(7) rad m−2, that are substantially lower than the RM derived from bursts emitted by FRB 121102. We find that the DM distribution of our events, combined with the nine other repeaters discovered by CHIME/FRB, is indistinguishable from that of thus far non-repeating CHIME/FRB events. However, as previously reported, the burst widths appear statistically significantly larger than the thus far non-repeating CHIME/FRB events, further supporting the notion of inherently different emission mechanisms and/or local environments. These results are consistent with previous work, though are now derived from 18 repeating sources discovered by CHIME/FRB during its first year of operation. We identify candidate galaxies that may contain FRB 190303.J1353+48 (DM = 222.4 pc cm−3).
Abstract
We present a Monte Carlo–based population synthesis study of fast radio burst (FRB) dispersion and scattering focusing on the first catalog of sources detected with the Canadian Hydrogen ...Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) project. We simulate intrinsic properties and propagation effects for a variety of FRB population models and compare the simulated distributions of dispersion measures and scattering timescales with the corresponding distributions from the CHIME/FRB catalog. Our simulations confirm the results of previous population studies, which suggested that the interstellar medium of the host galaxy alone (simulated based on the NE2001 model) cannot explain the observed scattering timescales of FRBs. We therefore consider additional sources of scattering, namely, the circumgalactic medium (CGM) of intervening galaxies and the circumburst medium whose properties are modeled based on typical Galactic plane environments. We find that a population of FRBs with scattering contributed by these media is marginally consistent with the CHIME/FRB catalog. In this scenario, our simulations favor a population of FRBs offset from their galaxy centers over a population that is distributed along the spiral arms. However, if the models proposing the CGM as a source of intense scattering are incorrect, then we conclude that FRBs may inhabit environments with more extreme properties than those inferred for pulsars in the Milky Way.
This paper presents the theoretical analysis results of the relations between the geometric parameters of the reflector of a parabolic trough collector (PTC) system and the focal shape formed by the ...defocusing phenomenon of the non-parallel solar beam firstly. Then the effects of these designed parameters and the defocusing phenomenon on the comprehensive characteristics and performance of the whole process of the photo-thermal conversion in the PTC system were numerically studied and optimized, using a proposed three-dimensional integrated model combined the Finite Volume Method (FVM) with the Monte Carlo Ray-Trace (MCRT) method. It is revealed that the numerical results can be well explained by the theoretical analysis results, proving that the model and method used in the present study is feasible and reliable. It is also found that the comprehensive characteristics and performance are very different from some critical points determined by the defocusing phenomenon of the non-parallel solar beam. From these critical points, the optional ranges of the geometric parameters of the reflector are determined to collect the entire reflected beam from the reflector, with relative optimized performance. In addition, an improved description for the characteristics of the solar flux density distributions on the absorber tube is further presented.
•It is to present an analytical method or reference for designing more effective PTC.•Relations between the focal shape and the geometric parameters were analyzed.•Effects of the geometric parameters were studied by the FVM combined with the MCRT.•The comprehensive performance is mainly determined by the defocusing phenomenon.•Optional ranges of geometric parameters with optimized performance can be determined.
We report on the detection of seven bursts from the periodically active, repeating fast radio burst (FRB) source FRB 180916.J0158+65 in the 300-400 MHz frequency range with the Green Bank Telescope ...(GBT). Emission in multiple bursts is visible down to the bottom of the GBT band, suggesting that the cutoff frequency (if it exists) for FRB emission is lower than 300 MHz. Observations were conducted during predicted periods of activity of the source, and had simultaneous coverage with the Low Frequency Array (LOFAR) and the FRB backend on the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. We find that one of the GBT-detected bursts has potentially associated emission in the CHIME band (400-800 MHz) but we detect no bursts in the LOFAR band (110-190 MHz), placing a limit of on the spectral index of broadband emission from the source. We also find that emission from the source is severely band-limited with burst bandwidths as low as ∼40 MHz. In addition, we place the strictest constraint on observable scattering of the source, <1.7 ms at 350 MHz, suggesting that the circumburst environment does not have strong scattering properties. Additionally, knowing that the circumburst environment is optically thin to free-free absorption at 300 MHz, we find evidence against the association of a hyper-compact H ii region or a young supernova remnant (age <50 yr) with the source.
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