Sol–gel processing represents a powerful and versatile strategy for the preparation of functional inorganic and hybrid materials that facilitate control over the molecular composition, as well as ...organization of the materials at the various length scales relevant to fundamental and applied research. Recent advances have enabled its use for the processing of an emerging class of functional porous materials called metal–organic frameworks (MOFs). Here, sol–gel approaches can be employed for the direct manipulation of MOFs, or as a route to the construction of composite materials where the properties of the MOF are synergistically combined with those of a carefully chosen inorganic phase. In this review, we present the most significant progress made in this emerging area, according to four main synthetic strategies, with a particular focus on describing how sol–gel processing enhances the functionalities of the MOF. These strategies include (1) molecular scale manipulations of the pore surfaces of MOFs with sol–gel precursors; (2) the controlled positioning or growth of MOF crystals on inorganic surfaces; (3) the use of MOF crystals as templates for sol–gel processes (either within the pores, or at the external surfaces); and (4) the use of sol–gel-derived sacrificial inorganic templates for the structuring of MOF-based architectures. Each of these processing methods imparts unique properties to the systems and provides a route to higher-order architectures and material compositions not accessible through conventional approaches to MOF synthesis. Sol–gel processing provides promising routes toward new functional materials that display enhanced properties and are expected to play an important role in allowing MOFs to be optimized for specific applications.
Background Previous studies have assessed the prevalence and characteristics of self-medication in COVID-19. However, no systematic review has summarized their findings. Objective We conducted a ...systematic review to assess the prevalence of self-medication to prevent or manage COVID-19. Methods We used different keywords and searched studies published in PubMed, Scopus, Web of Science, Embase, two preprint repositories, Google, and Google Scholar. We included studies that reported original data and assessed self-medication to prevent or manage COVID-19. The risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) modified for cross-sectional studies. Results We identified eight studies, all studies were cross-sectional, and only one detailed the question used to assess self-medication. The recall period was heterogeneous across studies. Of the eight studies, seven assessed self-medication without focusing on a specific symptom: four performed in the general population (self-medication prevalence ranged between <4% to 88.3%) and three in specific populations (range: 33.9% to 51.3%). In these seven studies, the most used medications varied widely, including antibiotics, chloroquine or hydroxychloroquine, acetaminophen, vitamins or supplements, ivermectin, and ibuprofen. The last study only assessed self-medication for fever due to COVID-19. Most studies had a risk of bias in the "representativeness of the sample" and "assessment of outcome" items of the NOS. Conclusions Studies that assessed self-medication for COVID-19 found heterogeneous results regarding self-medication prevalence and medications used. More well-designed and adequately reported studies are warranted to assess this topic.
Metal–organic frameworks (MOFs) are some of the most interesting and promising candidates to sequester toxic H2S and SO2 gases. MOFs show interesting advantages over classic porous materials due to ...their chemical composition, ligand functionality, cavity dimensions, ease of preparation, and relatively low cost reactivation. The optimization of the physical–chemical interactions between MOFs and H2S and SO2 molecules is the key to further amplification of their capture. Reversibility after the adsorption of H2S and SO2 can be modulated through noncovalent bonding between functionalized ligands (within MOF structures) and H2S and SO2. This review aims to summarize recent advances in the development of MOF-based systems for the capture and removal of H2S and SO2. We anticipate that this review article can offer very useful information on the significant and rapid progress of the enhancement of H2S and SO2 capture by MOFs.
The first bioinspired microporous metal–organic framework (MOF) synthesized using ellagic acid, a common natural antioxidant and polyphenol building unit, is presented. Bi2O(H2O)2(C14H2O8)·nH2O ...(SU-101) was inspired by bismuth phenolate metallodrugs, and could be synthesized entirely from nonhazardous or edible reagents under ambient aqueous conditions, enabling simple scale-up. Reagent-grade and affordable dietary supplement-grade ellagic acid was sourced from tree bark and pomegranate hulls, respectively. Biocompatibility and colloidal stability were confirmed by in vitro assays. The material exhibits remarkable chemical stability for a bioinspired MOF (pH = 2–14, hydrothermal conditions, heated organic solvents, biological media, SO2 and H2S), attributed to the strongly chelating phenolates. A total H2S uptake of 15.95 mmol g–1 was recorded, representing one of the highest H2S capacities for a MOF, where polysulfides are formed inside the pores of the material. Phenolic phytochemicals remain largely unexplored as linkers for MOF synthesis, opening new avenues to design stable, eco-friendly, scalable, and low-cost MOFs for diverse applications, including drug delivery.
It is shown that the Majorana nature of the heavy neutrinos
N
j
having masses in the range of
M
j
~ (100 - 1000) GeV and present in the TeV scale type I and inverse see-saw scenarios of neutrino mass ...generation, is unlikely to be observable in the currently operating and future planned accelerator experiments (including LHC) due to the existence of very strong constraints on the parameters and couplings responsible for the corresponding ∣Δ
L
∣= 2 processes,
L
being the total lepton charge. If the heavy Majorana neutrinos
N
j
are observed and they are associated only with the type I or inverse see-saw mechanisms and no additional TeV scale “new physics”, they will behave like Dirac fermions to a relatively high level of precision, being actually pseudo-Dirac particles. The observation of effects proving the Majorana nature of
N
j
would imply that these heavy neutrinos have additional relatively strong couplings to the Standard Model particles (as, e.g. in the type III see-saw scenario), or that light neutrino masses compatible with the observations are generated by a mechanism other than see-saw (e.g., radiatively at one or two loop level) in which the heavy Majorana neutrinos
N
j
are nevertheless involved.
Schizophrenia and Parkinson's disease can be controlled with dopamine antagonists and agonists. In order to improve the understanding of the reaction mechanism of these drugs, in this investigation ...we present a quantum chemical study of 20 antagonists and 10 agonists. Electron donor acceptor capacity and global hardness are analyzed using Density Functional Theory calculations. Following this theoretical approach, we provide new insights into the intrinsic response of these chemical species. In summary, antagonists generally prove to be better electron acceptors and worse electron donors than dopamine, whereas agonists present an electron donor-acceptor capacity similar to that of dopamine. The chemical hardness is a descriptor that captures the resistance of a chemical compound to change its number of electrons. Within this model, harder molecules are less polarizable and more stable systems. Our results show that the global hardness is similar for dopamine and agonists whilst antagonists present smaller values. Following the Hard and Soft Acid and Bases principle, it is possible to conclude that dopamine and agonists are hard bases while antagonists are soft acids, and this can be related to their activity. From the electronic point of view, we have evolved a new perspective for the classification of agonist and antagonist, which may help to analyze future results of chemical interactions triggered by these drugs.
The Arabidopsis thaliana central cell, the companion cell of the egg, undergoes DNA demethylation before fertilization, but the targeting preferences, mechanism, and biological significance of this ...process remain unclear. Here, we show that active DNA demethylation mediated by the DEMETER DNA glycosylase accounts for all of the demethylation in the central cell and preferentially targets small, AT-rich, and nucleosome-depleted euchromatic transposable elements. The vegetative cell, the companion cell of sperm, also undergoes DEMETER-dependent demethylation of similar sequences, and lack of DEMETER in vegetative cells causes reduced small RNA—directed DNA methylation of transposons in sperm. Our results demonstrate that demethylation in companion cells reinforces transposon methylation in plant gametes and likely contributes to stable silencing of transposable elements across generations.
Malignant hyperthermia (MH) is a potentially lethal disorder triggered by certain anesthetics. Mutations in the ryanodine receptor 1 (RYR1) gene account for about half of MH cases. Discordance ...between the low incidence of MH and a high prevalence of mutations has been attributed to incomplete penetrance, which has not been quantified yet. The authors aimed to examine penetrance of MH-diagnostic RYR1 mutations and the likelihood of mutation carriers to develop MH, and to identify factors affecting severity of MH clinical expression.
In this multicenter case-control study, data from 125 MH pedigrees between 1994 and 2017 were collected from four European registries and one Canadian registry. Probands (survivors of MH reaction) and their relatives with at least one exposure to anesthetic triggers, carrying one diagnostic RYR1 mutation, were included. Penetrance (percentage of probands among all genotype-positive) and the probability of a mutation carrier to develop MH were obtained. MH onset time and Clinical Grading Scale score were used to assess MH reaction severity.
The overall penetrance of nine RYR1 diagnostic mutations was 40.6% (93 of 229), without statistical differences among mutations. Likelihood to develop MH on exposure to triggers was 0.25 among all RYR1 mutation carriers, and 0.76 in probands (95% CI of the difference 0.41 to 0.59). Penetrance in males was significantly higher than in females (50% 62 of 124 vs. 29.7% 30 of 101; P = 0.002). Males had increased odds of developing MH (odds ratio, 2.37; 95% CI, 1.36 to 4.12) despite similar levels of exposure to trigger anesthetics. Proband's median age was 12 yr (interquartile range 6 to 32.5).
Nine MH-diagnostic RYR1 mutations have sex-dependent incomplete penetrance, whereas MH clinical expression is influenced by patient's age and the type of anesthetic. Our quantitative evaluation of MH penetrance reinforces the notion that a previous uneventful anesthetic does not preclude the possibility of developing MH.
A
bstract
We perform a detailed analysis of lepton flavour violation (LFV) within minimal see-saw type extensions of the Standard Model (SM), which give a viable mechanism of neutrino mass generation ...and provide new particle content at the electroweak scale. We focus, mainly, on predictions and constraints set on each scenario from
μ
→
e
γ,
μ
→ 3
e
and
μ
−
e
conversion in the nuclei. In this class of models, the flavour structure of the Yukawa couplings between the additional scalar and fermion representations and the SM leptons is highly constrained by neutrino oscillation measurements. In particular, we show that in some regions of the parameters space of type I and type II see-saw models, the Dirac and Majorana phases of the neutrino mixing matrix, the ordering and hierarchy of the active neutrino mass spectrum as well as the value of the reactor mixing angle
θ
13
may considerably affect the size of the LFV observables. The interplay of the latter clearly allows to discriminate among the different low energy see-saw possibilities.
A vast amount of evidence indicates that bisphenol A (BPA) and phthalates are widely distributed in the environment since these compounds are mass-produced for the manufacture of plastics and ...plasticizers. These compounds belong to a large group of substances termed endocrine-disrupting chemicals (EDC). It is well known that humans and living organisms are unavoidably and unintentionally exposed to BPA and phthalates from food packaging materials and many other everyday products. BPA and phthalates exert their effect by interfering with hormone synthesis, bioavailability, and action, thereby altering cellular proliferation and differentiation, tissue development, and the regulation of several physiological processes. In fact, these EDC can alter fetal programming at an epigenetic level, which can be transgenerational transmitted and may be involved in the development of various chronic pathologies later in the adulthood, including metabolic, reproductive and degenerative diseases, and certain types of cancer.
In this review, we describe the most recent proposed mechanisms of action of these EDC and offer a compelling selection of experimental, epidemiological and clinical studies, which show evidence of how exposure to these pollutants affects our health during development, and their association with a wide range of reproductive, metabolic and neurological diseases, as well as hormone-related cancers. We stress the importance of concern in the general population and the urgent need for the medical health care system to closely monitor EDC levels in the population due to unavoidable and involuntary exposure to these pollutants and their impact on human health.
Display omitted
•Human clinical trials demonstrate that endocrine-disrupting chemicals impact human health at multisystemic level.•Epidemiological studies show strong evidence of endocrine disruption associated with bisphenol A and phthalate exposure.•Health policies and biomonitoring should guarantee human health protection from endocrine disruptor exposure.
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