753 research outputs found
Cosmic Evolution with Early and Late Acceleration Inspired by Dual Nature of the Ricci Scalar Curvature
In the present paper, it is found that dark energy emerges spontaneously from
the modified gravity. According to cosmological scenario, obtained here, the
universe inflates for sec. in the beginning and late universe
accelerates after 8.58 Gyrs. During the long intermediate period, it
decelerates driven by radiation and subsequently by matter. Emerged
gravitational dark energy mimics quintessence and its density falls by 115
orders from its initial value to its current
value .Comment: 40 pages. To appearin Int. J. Mod. Phys.
Investigation of energy storage batteries in stability enforcement of low inertia active distribution network
Probabilistic Clustering of Time-Evolving Distance Data
We present a novel probabilistic clustering model for objects that are
represented via pairwise distances and observed at different time points. The
proposed method utilizes the information given by adjacent time points to find
the underlying cluster structure and obtain a smooth cluster evolution. This
approach allows the number of objects and clusters to differ at every time
point, and no identification on the identities of the objects is needed.
Further, the model does not require the number of clusters being specified in
advance -- they are instead determined automatically using a Dirichlet process
prior. We validate our model on synthetic data showing that the proposed method
is more accurate than state-of-the-art clustering methods. Finally, we use our
dynamic clustering model to analyze and illustrate the evolution of brain
cancer patients over time
Genetic analysis of heat tolerance in hot pepper: insights from comprehensive phenotyping and QTL mapping
High temperatures present a formidable challenge to the cultivation of hot pepper, profoundly impacting not only vegetative growth but also leading to flower and fruit abscission, thereby causing a significant reduction in yield. To unravel the intricate genetic mechanisms governing heat tolerance in hot pepper, an F2 population was developed through the crossing of two distinct genotypes exhibiting contrasting heat tolerance characteristics: DLS-161-1 (heat tolerant) and DChBL-240 (heat susceptible). The F2 population, along with the parental lines, was subjected to comprehensive phenotyping encompassing diverse morphological, physiological, and biochemical heat-related traits under high temperature conditions (with maximum temperature ranging from 31 to 46.5°C and minimum temperature from 15.4 to 30.5°C). Leveraging the Illumina Nova Seq-6000 platform, Double digest restriction-site associated DNA sequencing (ddRAD-seq) was employed to generate 67.215 Gb data, with subsequent alignment of 218.93 million processed reads against the reference genome of Capsicum annuum. Subsequent variant calling and ordering resulted in 5806 polymorphic SNP markers grouped into 12 LGs. Further QTL analysis identified 64 QTLs with LOD values ranging from 2.517 to 11.170 and explained phenotypic variance ranging from 4.05 to 19.39%. Among them, 21 QTLs, explaining more than 10% phenotypic variance, were identified as major QTLs controlling 9 morphological, 3 physiological, and 2 biochemical traits. Interestingly, several QTLs governing distinct parameters were found to be colocalized, suggesting either a profound correlation between the QTLs regulating these traits or their significant genomic proximity. In addition to the QTLs, we also identified 368380 SSR loci within the identified QTL regions, dinucleotides being the most abundant type (211,381). These findings provide valuable insights into the genetics of heat tolerance in hot peppers. The identified QTLs and SSR markers offer opportunities to develop heat-tolerant varieties, ensuring better crop performance under high-temperature conditions
Karyotype, Sex Determination, and Meiotic Chromosome Behavior in Two Pholcid (Araneomorphae, Pholcidae) Spiders: Implications for Karyotype Evolution
There are 1,111 species of pholcid spiders, of which less than 2% have published karyotypes. Our aim in this study was to determine the karyotypes and sex determination mechanisms of two species of pholcids: Physocyclus mexicanus (Banks, 1898) and Holocnemus pluchei (Scopoli, 1763), and to observe sex chromosome behavior during meiosis. We constructed karyotypes for P. mexicanus and H. pluchei using information from both living and fixed cells. We found that P. mexicanus has a chromosome number of 2n = 15 in males and 2n = 16 in females with X0-XX sex determination, like other members of the genus Physocyclus. H. pluchei has a chromosome number of 2n = 28 in males and 2n = 28 in females with XY-XX sex determination, which is substantially different from its closest relatives. These data contribute to our knowledge of the evolution of this large and geographically ubiquitous family, and are the first evidence of XY-XX sex determination in pholcids
Comparative Study of rK39 Leishmania Antigen for Serodiagnosis of Visceral Leishmaniasis: Systematic Review with Meta-Analysis
Visceral Leishmaniasis (VL) is a neglected tropical disease for which serodiagnostic tests are available, but not yet widely implemented in rural areas. The rK39 recombinant protein is derived from a kinesin-like protein of parasites belonging to the Leishmania donovani complex, and has been used in the last two decades for the serodiagnosis of VL. We present here a systematic review and meta-analysis of studies evaluating serologic assays (rK39 strip-test, rK39 ELISA, Direct Agglutination Test [DAT], Indirect Immunofluorescence test [IFAT] and ELISA with a promastigote antigen preparation [p-ELISA]) to diagnose VL to determine the accuracy of rK39 antigen in comparison to the use of other antigen preparations. Fourteen papers fulfilled the inclusion and exclusion selection criteria. The summarized sensitivity for the rK39-ELISA was 92% followed by IFAT 88% and p-ELISA 87%. The summarized specificity for the three diagnostic tests was 81%, 90%, and 77%. Studies comparing the rK39 strip test with DAT found a similar sensitivity (94%) and specificity (89%). However, the rK39 strip test was more specific than the IFAT and p-ELISA. In conclusion, we found the rK39 protein used either in a strip test or in an ELISA is a good choice for the serodiagnosis of VL
Interactions between HIV-1 Reverse Transcriptase and the Downstream Template Strand in Stable Complexes with Primer-Template
Background: Human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) forms stable ternary complexes in which RT is bound tightly at fixed positions on the primer-template (P/T). We have probed downstream interactions between RT and the template strand in the complex containing the incoming dNTP (+1 dNTPNRTNP/T complex) and in the complex containing the pyrophosphate analog, foscarnet (foscarnetNRTNP/T complex). Methods and Results: UV-induced cross-linking between RT and the DNA template strand was most efficient when a bromodeoxyuridine residue was placed in the +2 position (the first template position downstream from the incoming dNTP). Furthermore, formation of the +1 dNTPNRTNP/T complex on a biotin-containing template inhibited binding of streptavidin when biotin was in the +2 position on the template but not when the biotin was in the +3 position. Streptavidin pre-bound to a biotin residue in the template caused RT to stall two to three nucleotides upstream from the biotin residue. The downstream border of the complex formed by the stalled RT was mapped by digestion with exonuclease RecJF. UV-induced cross-linking of the complex formed by the pyrophosphate analog, foscarnet, with RT and P/T occurred preferentially with bromodeoxyuridine in the +1 position on the template in keeping with the location of RT one base upstream in the foscarnetNRTNP/T complex (i.e., in the pre-translocation position). Conclusions: For +1 dNTPNRTNP/T and foscarnetNRTNP/T stable complexes, tight interactions were observed between RT an
QGP Theory: Status and Perspectives
The current status of Quark-Gluon-Plasma Theory is reviewed. Special emphasis
is placed on QGP signatures, the interpretation of current data and what to
expect from RHIC in the near future.Comment: 20 pages, invited overview talk at the 4th International Conference
on the Physcis and Astrophysics of the Quark-Gluon-Plasma, November 2001,
Jaipur, India, to appear in Praman
Hemorrhage of brain metastasis from non-small cell lung cancer post gefitinib therapy: two case reports and review of the literature
<p>Abstract</p> <p>Background</p> <p>Gefitinib is one of the small molecule inhibitors of epidermal growth factor receptor tyrosine kinase (EGFR TKIs). Clinical trials have demonstrated it is effective for treatment of a subset of patients with advanced non-small cell lung cancer (NSCLC). Gefitinib has been generally considered to be a relatively safe agent. Besides a small proportion of fatal interstitial pneumonia, the common adverse drug reactions of gefitinib include diarrhea and skin rash, which are generally mild and reversible. Herein, we report the first two cases of brain metastasis hemorrhage that might be involved with the use of gefitinib.</p> <p>Case presentation</p> <p>Two patients with brain metastasis from NSCLC developed brain hemorrhage after gefitinib therapy. The hemorrhage in one case occurred one month after gefitinib combined with whole brain radiation therapy (WBRT), and in the another case hemorrhage developed slowly within brain metastases eight months post gefitinib monotherapy for diffuse pulmonary metastasis from a lung cancer undergone surgical removal previously.</p> <p>Conclusion</p> <p>We speculate brain hemorrhage could be one of the adverse drug reactions of gefitinib treatment for NSCLC and suggest clinicians be aware of this possible rare entity. More data are needed to confirm our findings, especially when gefitinib is used in the settings of brain metastases from NSCLC or other origins.</p
Anti-Angiogenic Activity of a Small Molecule STAT3 Inhibitor LLL12
Background: Recent data indicate the Signal Transducer and Activator of Transcription 3 (STAT3) pathway is required for VEGF production and angiogenesis in various types of cancers. STAT3 inhibitors have been shown to reduce tumor microvessel density in tumors but a direct anti-angiogenic activity has not been described. Methodology/Principal Findings: We investigated the direct action of a small molecule inhibitor of STAT3 (LLL12) in human umbilical cord vascular endothelial cells (HUVECs) in vitro, in a Matrigel model for angiogenesis in vivo, and its antitumor activity in a xenograft model of osteosarcoma. LLL12 (100 nM) significantly inhibited VEGF-stimulated STAT3 phosphorylation in HUVECs, reduced their proliferation/migration and inhibited VEGF-induced tube formation. Morphologic analysis of LLL12 treated HUVECs demonstrated marked changes in actin/tubulin distribution and bundling. In scid mice, LLL12 reduced microvessel invasion into VEGF-infused Matrigel plugs by,90 % at a dose of 5 mg/kg daily. Following a period of tumor progression (2 weeks), LLL12 completely suppressed further growth of established OS-1 osteosarcoma xenografts. Pharmacodynamic studies showed robust phosphorylated STAT3 in control tumors, whereas phospho-STAT3 was not detected in LLL12-treated OS-1 tumors. Treated tumors demonstrated decreased proliferation (Ki67 staining), and decreased microvessel density (CD34 staining), but no significant increase in apoptosis (TUNEL staining), relative to controls. Assay of angiogenic factors, using an antibody array, showed VEGF, MMP-9, Angiopoietin1/2, Tissue Factor and FGF-
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