Metabolomics is the systematic study of all the metabolites present within a biological system, which consists of a mass of molecules, having a variety of physical and chemical properties and ...existing over an extensive dynamic range in biological samples. Diverse analytical techniques are needed to achieve higher coverage of metabolites. The application of mass spectrometry (MS) in metabolomics has increased exponentially since the discovery and development of electrospray ionization and matrix-assisted laser desorption ionization techniques. Significant advances have also occurred in separation-based MS techniques (gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, capillary electrophoresis-mass spectrometry, and ion mobility-mass spectrometry), as well as separation-free MS techniques (direct infusion-mass spectrometry, matrix-assisted laser desorption ionization-mass spectrometry, mass spectrometry imaging, and direct analysis in real time mass spectrometry) in the past decades. This review presents a brief overview of the recent advanced MS techniques and their latest applications in metabolomics. The software/websites for MS result analyses are also reviewed.
Metabolomics is the systematic study of all the metabolites present within a biological system, supply functional information and has received extensive attention in the field of life sciences.
The coupling of aromatic electrophiles (aryl halides, aryl ethers, aryl acids, aryl nitriles etc.) with nucleophiles is a core methodology for the synthesis of aryl compounds. Transformations of aryl ...ketones in an analogous manner via carbon–carbon bond activation could greatly expand the toolbox for the synthesis of aryl compounds due to the abundance of aryl ketones. An exploratory study of this approach is typically based on carbon–carbon cleavage triggered by ring‐strain release and chelation assistance, and the products are also limited to a specific structural motif. Here we report a ligand‐promoted β‐carbon elimination strategy to activate the carbon–carbon bonds, which results in a range of transformations of aryl ketones, leading to useful aryl borates, and also to biaryls, aryl nitriles, and aryl alkenes. The use of a pyridine‐oxazoline ligand is crucial for this catalytic transformation. A gram‐scale borylation reaction of an aryl ketone via a simple one‐pot operation is reported. The potential utility of this strategy is also demonstrated by the late‐stage diversification of drug molecules probenecid, adapalene, and desoxyestrone, the fragrance tonalid as well as the natural product apocynin.
The unstrained carbon–carbon bond of an aryl ketone can be activated by a Pd‐catalyzed ligand‐promoted β‐carbon elimination reaction. In this way, aryl ketones can be transformed into useful aryl borates, and also to biaryls, aryl nitriles, and aryl alkenes. The utility of this strategy was demonstrated by the late‐stage diversification of several drug molecules.
AbstractObjectiveTo study the clinical characteristics of patients in Zhejiang province, China, infected with the 2019 severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) responsible for ...coronavirus disease 2019 (covid-2019).DesignRetrospective case series.SettingSeven hospitals in Zhejiang province, China.Participants62 patients admitted to hospital with laboratory confirmed SARS-Cov-2 infection. Data were collected from 10 January 2020 to 26 January 2020.Main outcome measuresClinical data, collected using a standardised case report form, such as temperature, history of exposure, incubation period. If information was not clear, the working group in Hangzhou contacted the doctor responsible for treating the patient for clarification.ResultsOf the 62 patients studied (median age 41 years), only one was admitted to an intensive care unit, and no patients died during the study. According to research, none of the infected patients in Zhejiang province were ever exposed to the Huanan seafood market, the original source of the virus; all studied cases were infected by human to human transmission. The most common symptoms at onset of illness were fever in 48 (77%) patients, cough in 50 (81%), expectoration in 35 (56%), headache in 21 (34%), myalgia or fatigue in 32 (52%), diarrhoea in 3 (8%), and haemoptysis in 2 (3%). Only two patients (3%) developed shortness of breath on admission. The median time from exposure to onset of illness was 4 days (interquartile range 3-5 days), and from onset of symptoms to first hospital admission was 2 (1-4) days.ConclusionAs of early February 2020, compared with patients initially infected with SARS-Cov-2 in Wuhan, the symptoms of patients in Zhejiang province are relatively mild.
Abstract
Some quasi-thermal (QT)-dominated gamma-ray bursts (GRBs) could be well described by a multicolor blackbody (mBB) function or a combined model of a BB plus a nonthermal (NT) component. In ...this analysis, two QT radiation-dominated bursts with known emission properties (GRB 210610B, likely from a hybrid jet, and GRB 210121A, with a spectrum consistent with nondissipative photospheric emission from a pure hot fireball) are used to make a comparison between these two models. To diagnose the magnetization properties of the central engine, the “top-down” approach proposed by Gao and Zhang is adopted. It is found that diagnoses based on these two models provide similar conclusions qualitatively; however, the model with mBB (or mBB+NT) may give more reasonable physical explanations. This implies that impacts from the GRB jet structure and geometrical broadening on the observed spectrum should be considered. However, conservatively, these methods may be not sensitive enough to distinguish between a pure hot fireball and a mildly magnetized hybrid jet. Some other information is necessary to provide more evidence when determining the jet properties for similar GRBs. Based on these considerations, we suggest that the photospheric emission of GRB 221022B is from a hot jet, where dissipation is caused by an internal shock mechanism due to the increasing Lorentz factor with time, which makes its prompt emission display typical evolution from thermal to NT.
Recent wide-field surveys discovered new types of peculiar optical transients that showed diverse behaviors of the evolution of photospheric properties. We develop a general theory of homologous ...explosions with constant opacity, paying special attention to the evolution of the photospheric radius Rph. We find that regardless of the density distribution profile, Rph always increases early on and decreases at late times. This result does not depend on the radiation and cooling processes inside the ejecta. The general rising/falling behavior of Rph can be used to quickly diagnose whether the source originates from a supernova-like explosion. The shape of the Rph evolution curve depends on the density profile, so the observations may be used to directly diagnose the density profile as well as the temperature profile of the ejecta. All of the well-monitored supernovae show such a Rph rising/falling behavior, which is consistent with our theory. The recently discovered peculiar transient AT 2018cow showed a continuous decay of Rph, for which a supernova-like explosion origin is disfavored. Our result therefore supports the interpretation of this transient as a tidal disruption event.
In this paper we collect 19 hydrogen-deficient superluminous supernovae (SLSNe) and fit their light curves, temperature evolution, and velocity evolution based on the magnetar-powered model. To ...obtain the best-fitting parameters, we incorporate the Markov chain Monte Carlo approach. We get rather good fits for seven events (χ2/dof = 0.24-0.96) and good fits for another seven events (χ2/dof = 1.37-3.13). We find that the initial periods (P0) and magnetic strength (Bp) of the magnetars that supposedly power these SLSNe are in the range of ∼1.2-8.3 ms and G, respectively; the inferred masses of the ejecta of these SLSNe are between 1 and , and the values of the gamma-ray opacity are between 0.01 and 0.82 cm2 g−1. We also calculate the fraction of the initial rotational energy of the magnetars harbored in the centers of the remnants of these SLSNe that is converted to the kinetic energy of the ejecta and find that the fraction is ∼19%-97% for different values of P0 and Bp, indicating that the acceleration effect cannot be neglected. Moreover, we find that the initial kinetic energies of most of these SLSNe are so small ( erg) that they can be easily explained by the neutrino-driven mechanism. These results can help clarify some important issues related to the energy-source mechanisms and explosion mechanisms and reveal the nature of SLSNe.
Quality control of traditional Chinese medicine (TCM) is the basis of clinical efficacy. Due to the complexity of TCM, it is difficult to unify the quality control, and hinders the further ...implementation of the quality standardization of TCM. As a new concept, quality-marker (Q-marker) plays a powerful role in promoting the standardization of quality control system of TCM.
The present review aims to provide reference and scientific basis for further development of Q-marker and assist standardization of quality control of TCM.
Extensive search of various documents and electronic databases such as Pubmed, Royal Society of Chemistry, Science Direct, Springer, Web of Science, and Wiley, etc., were used to search scientific contributions. Other online academic libraries, e.g. Google Scholars, Scopus and national pharmacology literature were also been employed to learn more relevant information about Q-marker.
Q-markers play vital role in promoting the standardization of quality control of TCM. The factors that affect the quality of TCM, the advantages and disadvantages of the analytical techniques commonly used in Q-marker research were reviewed, as well as the systematic research strategies, which were verified by practices.
The proposal of Q-marker not only provided a new perspective to break through the bottleneck of current quality control, but also can be used in the evaluation of pharmacological efficiency, therapeutic discovery, toxicology, etc. In addition, the Q-marker analysis strategies summarized in this paper is helpful to standardize the quality control of TCM and promote the internationalization of TCM.
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Astrocytes can serve multiple functions in maintaining cellular homeostasis of the central nervous system (CNS), and normal functions for autophagy in astrocytes is considered to have very vital ...roles in the pathogenesis of aging and neurodegenerative diseases. Autophagy is a major intracellular lysosomal (or its yeast analog, vacuolar) clearance pathways involved in the degradation and recycling of long-lived proteins, oxidatively damaged proteins and dysfunctional organelles by lysosomes. Current evidence has shown that autophagy might influence inflammation, oxidative stress, aging and function of astrocytes. Although the interrelation between autophagy and inflammation, oxidative stress, aging or neurological disorders have been addressed in detail, the influence of astrocytes mediated-autophagy in aging and neurodegenerative disorders has yet to be fully reviewed. In this review, we will summarize the most up-to-date findings and highlight the role of autophagy in astrocytes and link autophagy of astrocytes to aging and neurodegenerative diseases. Due to the prominent roles of astrocytic autophagy in age-related neurodegenerative diseases, we believe that we can provide new suggestions for the treatment of these disorders.
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