Endocrine-disrupting chemicals (EDCs) might increase the risk of childhood diseases by disrupting hormone-mediated processes that are critical for growth and development during gestation, infancy and ...childhood. The fetus, infant and child might have enhanced sensitivity to environmental stressors such as EDCs due to their rapid development and increased exposure to some EDCs as a consequence of development-specific behaviour, anatomy and physiology. In this Review, I discuss epidemiological studies examining the relationship between early-life exposure to bisphenol A (BPA), phthalates, triclosan and perfluoroalkyl substances (PFAS) with childhood neurobehavioural disorders and obesity. The available epidemiological evidence suggest that prenatal exposure to several of these ubiquitous EDCs is associated with adverse neurobehaviour (BPA and phthalates) and excess adiposity or increased risk of obesity and/or overweight (PFAS). Quantifying the effects of EDC mixtures, improving EDC exposure assessment, reducing bias from confounding, identifying periods of heightened vulnerability and elucidating the presence and nature of sexually dimorphic EDC effects would enable stronger inferences to be made from epidemiological studies than currently possible. Ultimately, improved estimates of the causal effects of EDC exposures on child health could help identify susceptible subpopulations and lead to public health interventions to reduce these exposures.
A
bstract
We present explicit expressions for the tree-level “kinematic” twist-three contributions to the nucleon matrix elements of gauge-invariant nonlocal quark-antiquark operators which can be ...used in lattice calculations of generalized parton distributions (GPDs). These contributions in particular restore the translation invariance of the results up to higher twist four. The calculated twist-three corrections are logarithmically enhanced as compared to the leading twist, and are discontinuous at the kinematic points
x
= ±
ξ
.
The EPA recently proposed national standards that would limit concentrations of six PFAS in public drinking-water supplies. Additional action may be needed to address PFAS exposure and related ...diseases.
Humans are exposed to a large number of environmental chemicals: Some of these may be toxic, and many others have unknown or poorly characterized health effects. There is intense interest in ...determining the impact of exposure to environmental chemical mixtures on human health. As the study of mixtures continues to evolve in the field of environmental epidemiology, it is imperative that we understand the methodologic challenges of this research and the types of questions we can address using epidemiological data. In this article, we summarize some of the unique challenges in exposure assessment, statistical methods, and methodology that epidemiologists face in addressing chemical mixtures. We propose three broad questions that epidemiological studies can address: a) What are the potential health impacts of individual chemical agents? b) What is the interaction among agents? And c) what are the health effects of cumulative exposure to multiple agents? As the field of mixtures research grows, we can use these three questions as a basis for defining our research questions and for developing methods that will help us better understand the effect of chemical exposures on human disease and well-being.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
We performed a systematic review of the epidemiology literature to identify the male reproductive effects associated with phthalate exposure.
Six phthalates were included in the review: ...di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), butyl benzyl phthalate (BBP), and diethyl phthalate (DEP). The initial literature search (of PubMed, Web of Science, and Toxline) included all studies of male reproductive effects in humans, and outcomes were selected for full systematic review based on data availability.
For each outcome, studies were evaluated using criteria defined a priori for risk of bias and sensitivity by two reviewers using a domain-based approach. Evidence was synthesized by outcome and phthalate and strength of evidence was summarized using a structured framework.
The primary outcomes reviewed here are (number of included/excluded studies in parentheses): anogenital distance (6/1), semen parameters (15/9), time to pregnancy (3/5), testosterone (13/8), timing of pubertal development (5/15), and hypospadias/cryptorchidism (4/10). Looking at the overall hazard, there was robust evidence of an association between DEHP and DBP exposure and male reproductive outcomes; this was based primarily on studies of anogenital distance, semen parameters, and testosterone for DEHP and semen parameters and time to pregnancy for DBP. There was moderate evidence of an association between DINP and BBP exposure and male reproductive outcomes based on testosterone and semen parameters for DINP and semen parameters and time to pregnancy for BBP. DIBP and DEP were considered to have slight evidence of an association. For DIBP, the less conclusive evidence was attributed to a more limited literature base (i.e., fewer studies) and lower exposure levels in the population, decreasing the ability to observe an effect. For DEP, the findings were consistent with experimental animal data that suggest DEP does not haves as strong an anti-androgenic effect as other phthalates.
Overall, despite some inconsistencies across phthalates in the specific outcomes associated with exposure, these results support that phthalate exposure at levels seen in human populations may have male reproductive effects, particularly DEHP and DBP. The relative strength of the evidence reflects differing levels of toxicity as well as differences in the range of exposures studied and the number of available studies.
The views expressed are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.
•Phthalate exposures at levels seen in human populations may have male reproductive effects, particularly DEHP and DBP.•The effects with the strongest associations with phthalate exposures were semen parameters and testosterone in adult men.•For DIBP and DINP, there is inadequate sensitivity in the available studies. It would be inappropriate to conclude that substituting these for DBP or DEHP would be health protective.
Four-pomeron vertex Braun, M. A.
European physical journal. C, Particles and fields,
12/2021, Letnik:
81, Številka:
12
Journal Article
Recenzirano
Odprti dostop
The four-pomeron vertex is studied in the perturbative QCD. Its dominating terms of the leading (zeroth and first) orders in the coupling constant and subdominant in the number of colors are ...constructed. The vertex consists of two terms, one with a derivative in rapidity
∂
y
and the other with the BFKL interaction between pomerons. The corresponding part of the action and equations of motion are found. The iterative solution of the latter is possible only for rapidities smaller than 2 and quite large coupling constant
α
s
, of the order or greater than unity, when the quadruple pomeron interaction is relatively small. Also iteration of the part with
∂
y
is unstable in the infrared region and compels to introduce an infrared cut. The variational approach with simple trying functions allows to find the minimum of the action at
α
s
of the order 0.2 and rapidities up to 25. Numerical estimates for O–O collisions show that actually the influence of the quadruple pomeron interaction turns out to be rather small.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•There is limited evidence of neurodevelopmental effects of phthalate exposure in humans.•The strongest evidence is for motor effects and BBP exposure in girls.•Evidence gaps need to be filled before ...concluding that there are minimal neurodevelopmental effects.
We performed a systematic review of the epidemiology literature to identify the neurodevelopmental effects associated with phthalate exposure.
Six phthalates were included in the review: di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), butyl benzyl phthalate (BBP), and diethyl phthalate (DEP). The initial literature search (of PubMed, Web of Science, and Toxline) included all studies of neurodevelopmental effects in humans, and outcomes were selected for full systematic review based on data availability.
Studies of neurodevelopmental effects were evaluated using criteria defined a priori for risk of bias and sensitivity by two reviewers using a domain-based approach. Evidence was synthesized by outcome and phthalate and strength of evidence was summarized using a structured framework. For studies of cognition and motor effects in children ≤4 years old, a random effects meta-analysis was performed.
The primary outcomes reviewed here are (number of studies in parentheses): cognition (14), motor effects (9), behavior, including attention deficit hyperactivity disorder (20), infant behavior (3), and social behavior, including autism spectrum disorder (7). For each phthalate/outcome combination, there was slight or indeterminate evidence of an association, with the exception of motor effects for BBP, which had moderate evidence.
Overall, there is not a clear pattern of association between prenatal phthalate exposures and neurodevelopment. There are several possible reasons for the observed null associations related to exposure misclassification, periods of heightened susceptibility, sex-specific effects, and the effects of phthalate mixtures. Until these limitations are adequately addressed in the epidemiology literature, these findings should not be interpreted as evidence that there are no neurodevelopmental effects of phthalate exposure.
The views expressed are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.
Trithorax-group proteins and their mammalian homologs, including those in BAF (mSWI/SNF) complexes, are known to oppose the activity of Polycomb repressive complexes (PRCs). This opposition underlies ...the tumor-suppressive role of BAF subunits and is expected to contribute to neurodevelopmental disorders. However, the mechanisms underlying opposition to Polycomb silencing are poorly understood. Here we report that recurrent disease-associated mutations in BAF subunits induce genome-wide increases in PRC deposition and activity. We show that point mutations in SMARCA4 (also known as BRG1) mapping to the ATPase domain cause loss of direct binding between BAF and PRC1 that occurs independently of chromatin. Release of this direct interaction is ATP dependent, consistent with a transient eviction mechanism. Using a new chemical-induced proximity assay, we find that BAF directly evicts Polycomb factors within minutes of its occupancy, thereby establishing a new mechanism for the widespread BAF-PRC opposition underlying development and disease.
In the effective action approach the imaginary part of the triple pomeron amplitude is calculated. The found dependence on the longitudinal momentum transfer
e
-
is found to separate as a simple ...factor
1
/
|
e
-
|
. This result is used to calculate the high-mass diffraction on a hadron and double scattering cross-section off a composite target.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Supraglacial debris affects glacier mass balance as a thin layer enhances surface melting, while a thick layer reduces it. While many glaciers are debris‐covered, global glacier models do not account ...for debris because its thickness is unknown. We provide the first globally distributed debris thickness estimates using a novel approach combining sub‐debris melt and surface temperature inversion methods. Results are evaluated against observations from 22 glaciers. We find the median global debris thickness is ∼0.15 ± 0.06 m. In all regions, the net effect of accounting for debris is a reduction in sub‐debris melt, on average, by 37%, which can impact regional mass balance by up to 0.40 m water equivalent (w.e.) yr‐1. We also find recent observations of similar thinning rates over debris‐covered and clean ice glacier tongues is primarily due to differences in ice dynamics. Our results demonstrate the importance of accounting for debris in glacier modeling efforts.
Plain Language Summary
Many glaciers around the world have a layer of debris (boulders, rocks, and sand) covering the underlying ice over much of the glacier surface, yet global glacier models do not account for debris because the debris thickness is unknown. Here we provide the first estimates of debris thickness for debris‐covered glaciers globally and show the debris substantially reduces regional glacier mass loss. We also find that recent observations that debris‐covered and clean ice glaciers are thinning at similar speeds is primarily due to differences in how glaciers flow. Our results fundamentally advance our ability to account for debris in glacier reconstructions, landscape evolution models, hazard assessments, and glacier projections of glacier runoff and their contribution to sea‐level rise.
Key Points
We produce the first distributed global debris thickness estimates
Accounting for debris significantly reduces regional glacier mass loss
The similar thinning rates of debris‐covered and clean ice glaciers in High Mountain Asia is primarily caused by differences in ice dynamics
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