300 research outputs found
MicroRNAs for Virus Pathogenicity and Host Responses, Identified in SARS-CoV-2 Genomes, May Play Roles in Viral-Host Co-Evolution in Putative Zoonotic Host Species
Our recent study identified seven key microRNAs (miR-8066, 5197, 3611, 3934-3p, 1307-3p, 3691-3p, 1468-5p) similar between SARS-CoV-2 and the human genome, pointing at miR-related mechanisms in viral entry and the regulatory effects on host immunity. To identify the putative roles of these miRs in zoonosis, we assessed their conservation, compared with humans, in some key wild and domestic animal carriers of zoonotic viruses, including bat, pangolin, pig, cow, rat, and chicken. Out of the seven miRs under study, miR-3611 was the most strongly conserved across all species; miR-5197 was the most conserved in pangolin, pig, cow, bat, and rat; miR-1307 was most strongly conserved in pangolin, pig, cow, bat, and human; miR-3691-3p in pangolin, cow, and human; miR-3934-3p in pig and cow, followed by pangolin and bat; miR-1468 was most conserved in pangolin, pig, and bat; while miR-8066 was most conserved in pangolin and pig. In humans, miR-3611 and miR-1307 were most conserved, while miR-8066, miR-5197, miR-3334-3p and miR-1468 were least conserved, compared with pangolin, pig, cow, and bat. Furthermore, we identified that changes in the miR-5197 nucleotides between pangolin and human can generate three new miRs, with differing tissue distribution in the brain, lung, intestines, lymph nodes, and muscle, and with different downstream regulatory effects on KEGG pathways. This may be of considerable importance as miR-5197 is localized in the spike protein transcript area of the SARS-CoV-2 genome. Our findings may indicate roles for these miRs in viralâhost co-evolution in zoonotic hosts, particularly highlighting pangolin, bat, cow, and pig as putative zoonotic carriers, while highlighting the miRsâ roles in KEGG pathways linked to viral pathogenicity and host responses in humans. This in silico study paves the way for investigations into the roles of miRs in zoonotic disease
The Role of CDK4 in the Pathogenesis of Pancreatic Cancer.
Pancreatic cancer (PC) continues to have the lowest overall survival and the lack of effective early diagnosis. Cyclin-dependent kinase 4 (CDK4) plays a fundamental role in the orderly progression of the cell cycle, binding to cyclin D to promote the progression through the G1/2 transition. The inhibition of CDK4/6 has therefore gained substantial interest in the hope of new and effective therapeutics in multiple cancers, such as advanced metastatic breast cancer. While the use of these agents is encouraging, their potential is yet to be fully explored. In this study we used the GLOBOCAN database to understand the most recent epidemiology of PC, Human Protein Atlas and KEGG to highlight the role, prevalence, and significance on patient survival of CDK4 in PC. We found that CDK4 cannot be used as prognostic in PC and no significant differences were observed between CDK4 expression and the patient's clinical status, though larger studies, especially concerning CDK4 protein expressions, are required for a more thorough understanding. The use of CDK4/6 inhibitors in PC is still in clinical trials. However, due to only modest improvements observed in the use of single-agent therapies, efforts have focused on combinatorial approaches
The Prediction of miRNAs in SARS-CoV-2 Genomes: hsa-miR Databases Identify 7 Key miRs Linked to Host Responses and Virus Pathogenicity-Related KEGG Pathways Significant for Comorbidities.
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a member of the betacoronavirus family, which causes COVID-19 disease. SARS-CoV-2 pathogenicity in humans leads to increased mortality rates due to alterations of significant pathways, including some resulting in exacerbated inflammatory responses linked to the "cytokine storm" and extensive lung pathology, as well as being linked to a number of comorbidities. Our current study compared five SARS-CoV-2 sequences from different geographical regions to those from SARS, MERS and two cold viruses, OC43 and 229E, to identify the presence of miR-like sequences. We identified seven key miRs, which highlight considerable differences between the SARS-CoV-2 sequences, compared with the other viruses. The level of conservation between the five SARS-CoV-2 sequences was identical but poor compared with the other sequences, with SARS showing the highest degree of conservation. This decrease in similarity could result in reduced levels of transcriptional control, as well as a change in the physiological effect of the virus and associated host-pathogen responses. MERS and the milder symptom viruses showed greater differences and even significant sequence gaps. This divergence away from the SARS-CoV-2 sequences broadly mirrors the phylogenetic relationships obtained from the whole-genome alignments. Therefore, patterns of mutation, occurring during sequence divergence from the longer established human viruses to the more recent ones, may have led to the emergence of sequence motifs that can be related directly to the pathogenicity of SARS-CoV-2. Importantly, we identified 7 key-microRNAs (miRs 8066, 5197, 3611, 3934-3p, 1307-3p, 3691-3p, 1468-5p) with significant links to KEGG pathways linked to viral pathogenicity and host responses. According to Bioproject data (PRJNA615032), SARS-CoV-2 mediated transcriptomic alterations were similar to the target pathways of the selected 7 miRs identified in our study. This mechanism could have considerable significance in determining the symptom spectrum of future potential pandemics. KEGG pathway analysis revealed a number of critical pathways linked to the seven identified miRs that may provide insight into the interplay between the virus and comorbidities. Based on our reported findings, miRNAs may constitute potential and effective therapeutic approaches in COVID-19 and its pathological consequences
Three electron beams from a laser-plasma wakefield accelerator and the energy apportioning question
Laser-wakefield accelerators are compact devices capable of delivering ultra-short electron bunches with pC-level charge and MeV-GeV energy by exploiting the ultra-high electric fields arising from the interaction of intense laser pulses with plasma. We show experimentally and through numerical simulations that a high-energy electron beam is produced simultaneously with two stable lower-energy beams that are ejected in oblique and counter-propagating directions, typically carrying off 5-10% of the initial laser energy. A MeV, 10s nC oblique beam is ejected in a 30-60 degree hollow cone, which is filled with more energetic electrons determined by the injection dynamics. A nC-level, 100s keV backward-directed beam is mainly produced at the leading edge of the plasma column. We discuss the apportioning of absorbed laser energy amongst the three beams. Knowledge of the distribution of laser energy and electron beam charge, which determine the overall efficiency, is important for various applications of laser-wakefield accelerators, including the development of staged high-energy accelerators
Wide-angle electron beams from laser-wakefield accelerators
Advances in laser technology have driven the development of laser-wakefield accelerators, compact devices that are capable of accelerating electrons to GeV energies over centimetre distances by exploiting the strong electric field gradients arising from the interaction of intense laser pulses with an underdense plasma. A side-effect of this acceleration mechanism is the production of high-charge, low-energy electron beams at wide angles. Here we present an experimental and numerical study of the properties of these wide-angle electron beams, and show that they carry off a significant fraction of the energy transferred from the laser to the plasma. These high-charge, wide-angle beams can also cause damage to laser-wakefield accelerators based on capillaries, as well as become source of unwanted bremsstrahlung radiation
The Library of Babel: On the origin of gravitational thermodynamics
We show that heavy pure states of gravity can appear to be mixed states to
almost all probes. For AdS_5 Schwarzschild black holes, our arguments are made
using the field theory dual to string theory in such spacetimes. Our results
follow from applying information theoretic notions to field theory operators
capable of describing very heavy states in gravity. For half-BPS states of the
theory which are incipient black holes, our account is exact: typical
microstates are described in gravity by a spacetime ``foam'', the precise
details of which are almost invisible to almost all probes. We show that
universal low-energy effective description of a foam of given global charges is
via certain singular spacetime geometries. When one of the specified charges is
the number of D-branes, the effective singular geometry is the half-BPS
``superstar''. We propose this as the general mechanism by which the effective
thermodynamic character of gravity emerges.Comment: LaTeX, 6 eps figures, uses young.sty and wick.sty; Version 2: typos
corrected, minor rewordings and clarifications, references adde
Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up
Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated
Detector Description and Performance for the First Coincidence Observations between LIGO and GEO
For 17 days in August and September 2002, the LIGO and GEO interferometer
gravitational wave detectors were operated in coincidence to produce their
first data for scientific analysis. Although the detectors were still far from
their design sensitivity levels, the data can be used to place better upper
limits on the flux of gravitational waves incident on the earth than previous
direct measurements. This paper describes the instruments and the data in some
detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial
change
B^0-\bar{B}^0 mixing and B \to X_s \gamma decay in the third type 2HDM: effects of NLO QCD contributions
In this paper, we calculated the next-to-leading order (NLO) new physics
contributions to the mass splitting \dmd and the branching ratio \brbxsga
induced by the charged Higgs loop diagrams in the third type of
two-Higgs-doublet models (model III) and draw the constraints on the free
parameters of model III. For the model III under consideration, we found that
(a) an upper limit |\ltt|\leq 1.7 is obtained from the precision data of
\dmd=0.502 \pm 0.007 ps^{-1}, while |\ltt| \approx 0.5 is favored
phenomenologicaly; (b) for decay, the NLO QCD contributions
tend to cancel the LO new physics contributions; (c) a light charged Higgs
boson with a mass around or even less than 200 GeV is still allowed at NLO
level by the measured branching ratio \brbxsga: numerically, 188 \leq \mh
\leq 215 GeV for (|\ltt|,|\lbb|)=(0.5,18); (d) the NLO QCD contributions
tend to cancel the LO contributions effectively, the lower limit on \mh is
consequently decreased by about 200 GeV; (e) the allowed region of \mh will
be shifted toward heavy mass end for a non-zero relative phase between
the Yukawa couplings \ltt and \lbb. The numerical results for the
conventional model II are also presented for the sake of a comparison.Comment: 42 pages, 18 eps figures, Revtex, new references adde
Early carboniferous brachiopod faunas from the Baoshan block, west Yunnan, southwest China
38 brachiopod species in 27 genera and subgenera are described from the Yudong Formation in the Shidian-Baoshan area, west Yunnan, southwest China. New taxa include two new subgenera: Unispirifer (Septimispirifer) and Brachythyrina (Longathyrina), and seven new species: Eomarginifera yunnanensis, Marginatia cylindrica, Unispirifer (Unispirifer) xiangshanensis, Unispirifer (Septimispirifer) wafangjieensis, Brachythyrina (Brachythyrina) transversa, Brachythyrina (Longathyrina) baoshanensis, and Girtyella wafangjieensis. Based on the described material and constraints from associated coral and conodont faunas, the age of the brachiopod fauna from the Yudon Formation is considered late Tournaisian (Early Carboniferous), with a possibility extending into earlyViseacutean.<br /
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