Microplastics are now recognized as widespread contaminants in the atmosphere, where, due to their small size and low density, they can be transported with winds around the Earth
. Atmospheric ...aerosols, such as mineral dust and other types of airborne particulate matter, influence Earth's climate by absorbing and scattering radiation (direct radiative effects) and their impacts are commonly quantified with the effective radiative forcing (ERF) metric
. However, the radiative effects of airborne microplastics and associated implications for global climate are unknown. Here we present calculations of the optical properties and direct radiative effects of airborne microplastics (excluding aerosol-cloud interactions). The ERF of airborne microplastics is computed to be 0.044 ± 0.399 milliwatts per square metre in the present-day atmosphere assuming a uniform surface concentration of 1 microplastic particle per cubic metre and a vertical distribution up to 10 kilometres altitude. However, there are large uncertainties in the geographical and vertical distribution of microplastics. Assuming that they are confined to the boundary layer, shortwave effects dominate and the microplastic ERF is approximately -0.746 ± 0.553 milliwatts per square metre. Compared with the total ERF due to aerosol-radiation interactions
(-0.71 to -0.14 watts per square metre), the microplastic ERF is small. However, plastic production has increased rapidly over the past 70 years
; without serious attempts to overhaul plastic production and waste-management practices, the abundance and ERF of airborne microplastics will continue to increase.
Skeletal muscle is one of the most dynamic and plastic tissues of the human body. In humans, skeletal muscle comprises approximately 40 % of total body weight and contains 50–75 % of all body ...proteins. In general, muscle mass depends on the balance between protein synthesis and degradation and both processes are sensitive to factors such as nutritional status, hormonal balance, physical activity/exercise, and injury or disease, among others. In this review, we discuss the various domains of muscle structure and function including its cytoskeletal architecture, excitation-contraction coupling, energy metabolism, and force and power generation. We will limit the discussion to human skeletal muscle and emphasize recent scientific literature on single muscle fibers.
Western Cambodia is recognized as the epicenter of Plasmodium falciparum multidrug resistance. Recent reports of the efficacy of dihydroartemisinin (DHA)-piperaquine (PP), the latest of the ...artemisinin-based combination therapies (ACTs) recommended by the WHO, have prompted further investigations. The clinical efficacy of dihydroartemisinin-piperaquine in uncomplicated falciparum malaria was assessed in western and eastern Cambodia over 42 days. Day 7 plasma piperaquine concentrations were measured and day 0 isolates tested for in vitro susceptibilities to piperaquine and mefloquine, polymorphisms in the K13 gene, and the copy number of the Pfmdr-1 gene. A total of 425 patients were recruited in 2011 to 2013. The proportion of patients with recrudescent infections was significantly higher in western (15.4%) than in eastern (2.5%) Cambodia (P <10(-3)). Day 7 plasma PP concentrations and median 50% inhibitory concentrations (IC50) of PP were independent of treatment outcomes, in contrast to median mefloquine IC50, which were found to be lower for isolates from patients with recrudescent infections (18.7 versus 39.7 nM; P = 0.005). The most significant risk factor associated with DHA-PP treatment failure was infection by parasites carrying the K13 mutant allele (odds ratio OR, 17.5; 95% confidence interval CI, 1 to 308; P = 0.04). Our data show evidence of P. falciparum resistance to PP in western Cambodia, an area of widespread artemisinin resistance. New therapeutic strategies, such as the use of triple ACTs, are urgently needed and must be tested. (This study has been registered at the Australian New Zealand Clinical Trials Registry under registration no. ACTRN12614000344695.).
Nuclear compartments have diverse roles in regulating gene expression, yet the molecular forces and components that drive compartment formation remain largely unclear
. The long non-coding RNA Xist ...establishes an intra-chromosomal compartment by localizing at a high concentration in a territory spatially close to its transcription locus
and binding diverse proteins
to achieve X-chromosome inactivation (XCI)
. The XCI process therefore serves as a paradigm for understanding how RNA-mediated recruitment of various proteins induces a functional compartment. The properties of the inactive X (Xi)-compartment are known to change over time, because after initial Xist spreading and transcriptional shutoff a state is reached in which gene silencing remains stable even if Xist is turned off
. Here we show that the Xist RNA-binding proteins PTBP1
, MATR3
, TDP-43
and CELF1
assemble on the multivalent E-repeat element of Xist
and, via self-aggregation and heterotypic protein-protein interactions, form a condensate
in the Xi. This condensate is required for gene silencing and for the anchoring of Xist to the Xi territory, and can be sustained in the absence of Xist. Notably, these E-repeat-binding proteins become essential coincident with transition to the Xist-independent XCI phase
, indicating that the condensate seeded by the E-repeat underlies the developmental switch from Xist-dependence to Xist-independence. Taken together, our data show that Xist forms the Xi compartment by seeding a heteromeric condensate that consists of ubiquitous RNA-binding proteins, revealing an unanticipated mechanism for heritable gene silencing.
Table of Contents Summary:
The annual
ACSM’s Health & Fitness Journal®
worldwide survey to determine industry trends by health fitness professionals is now in its 13th consecutive year. Strength ...training (the #5 trend in 2018) was dropped from this year’s survey because it was determined to be too generic. In previous surveys, educated, certified, and experienced fitness professionals that was a top performing trend (#1 in 2008–2013 and in the top 10 in every survey) also was dropped from the survey because it was too broad and lacked the necessary specificity. Employing certified fitness professionals was added as a potential new trend for 2019 and was rated #6. Wearable technology regained the #1 trend after dropping to #3 in 2018. Group training (more than five participants) was rated #2, which is the spot it held in 2018. Last year’s #1 trend, high-intensity interval training, dropped to #3 for 2019. Regaining spots in the top 20 fitness trends include mobile exercise devices (#13), worksite health promotion and workplace well-being programs (#15), outcome measurements (#16), and postrehabilitation classes (#20). Dropping out of the top 20 fitness trends include circuit weight training, sport-specific training, and core training. Four international experts independently commented on the results.
Apply It!
From this article, the reader should understand the following concepts:
Interferons (IFNs) are a family of cytokines with the unique ability to induce cell intrinsic programs that enhance resistance to viral infection. Induction of an antiviral state at the cell, tissue, ...organ, and organismal level is performed by three distinct IFN families, designated as Type-I, Type-II, and Type-III IFNs. Overall, there are 21 human IFNs, (16 type-I, 12 IFNαs, IFNβ, IFNϵ, IFNκ, and IFNω; 1 type-II, IFNγ; and 4 type-III, IFNλ1, IFNλ2, IFNλ3, and IFNλ4), that induce pleotropic cellular activities essential for innate and adaptive immune responses against virus and other pathogens. IFN signaling is initiated by binding to distinct heterodimeric receptor complexes. The three-dimensional structures of the type-I (IFNα/IFNAR1/IFNAR2), type-II (IFNγ/IFNGR1/IFNGR2), and type-III (IFNλ3/IFNλR1/IL10R2) signaling complexes have been determined. Here, we highlight similar and unique features of the IFNs, their cell surface complexes and discuss their role in inducing downstream IFN signaling responses.
Apply It!
From this article, the reader should understand the following concepts:
• Explain the differences between a fad and a trend
• Use the worldwide fitness trends in the commercial, corporate, ...clinical (including medical fitness), and community health fitness industry to further promote physical activity
• Study expert opinions about identified fitness trends for 2021
The rapid spread of Zika virus (ZIKV) and its association with abnormal brain development constitute a global health emergency. Congenital ZIKV infection produces a range of mild to severe ...pathologies, including microcephaly. To understand the pathophysiology of ZIKV infection, we used models of the developing brain that faithfully recapitulate the tissue architecture in early to midgestation. We identify the brain cell populations that are most susceptible to ZIKV infection in primary human tissue, provide evidence for a mechanism of viral entry, and show that a commonly used antibiotic protects cultured brain cells by reducing viral proliferation. In the brain, ZIKV preferentially infected neural stem cells, astrocytes, oligodendrocyte precursor cells, and microglia, whereas neurons were less susceptible to infection. These findings suggest mechanisms for microcephaly and other pathologic features of infants with congenital ZIKV infection that are not explained by neural stem cell infection alone, such as calcifications in the cortical plate. Furthermore, we find that blocking the glia-enriched putative viral entry receptor AXL reduced ZIKV infection of astrocytes in vitro, and genetic knockdown of AXL in a glial cell line nearly abolished infection. Finally, we evaluate 2,177 compounds, focusing on drugs safe in pregnancy. We show that the macrolide antibiotic azithromycin reduced viral proliferation and virus-induced cytopathic effects in glial cell lines and human astrocytes. Our characterization of infection in the developing human brain clarifies the pathogenesis of congenital ZIKV infection and provides the basis for investigating possible therapeutic strategies to safely alleviate or prevent the most severe consequences of the epidemic.
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