209 research outputs found

    First-passage functionals for Ornstein Uhlenbeck process with stochastic resetting

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    We study the statistical properties of first-passage Brownian functionals (FPBFs) of an Ornstein-Uhlenbeck (OU) process in the presence of stochastic resetting. We consider a one dimensional set-up where the diffusing particle sets off from x0x_0 and resets to xRx_R at a certain rate rr. The particle diffuses in a harmonic potential (with strength kk) which is centered around the origin. The center also serves as an absorbing boundary for the particle and we denote the first passage time of the particle to the center as tft_f. In this set-up, we investigate the following functionals: (i) local time Tloc=0tfdτ δ(xxR)T_{loc} = \int _0^{t_f}d \tau ~ \delta (x-x_R) i.e., the time a particle spends around xRx_R until the first passage, (ii) occupation or residence time Tres=0tfdτ θ(xxR)T_{res} = \int _0^{t_f} d \tau ~\theta (x-x_R) i.e., the time a particle typically spends above xRx_R until the first passage and (iii) the first passage time tft_f to the origin. We employ the Feynman-Kac formalism for renewal process to derive the analytical expression for the first moment of all the three FPBFs mentioned above. In particular, we find that resetting can either prolong or shorten the mean residence and first passage time depending on the system parameters. The transition between these two behaviors or phases can be characterized precisely in terms of optimal resetting rates, which interestingly undergo a continuous transition as we vary the trap stiffness kk. We characterize this transition and identify the critical -parameter \& -coefficient for both the cases. We also showcase other interesting interplay between the resetting rate and potential strength on the statistics of these observables. Our analytical results are in excellent agreement with the numerical simulations

    A promising cognition boosting effect of leaves of Abrus precatorius

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    Objective: To assess the leaves of Abrus precatorius had earlier show cognition boosting effect against dementia in rodents. Methods: The methanol extract was fractionated into ethyl acetate and aqueous fractions and assessed for its nootropic and learning activity in albino rodents. The effect of triterpenoids containing ethylacetate soluble fraction of methanol extract significant enhancement in the retention ability of amnesic mice as compared to their respective controls using elevated plus maze and Cook and Weidley’s pole apparatus. Subsequently, the extracts were further studied for its in vitro acetylcholinesterase (AChE) inhibitory potential which can correlate with an improvement in cholinergic transmission. Piracetam was used as the standard drug while scopolamine hydrobromide served as the amnestic agent. Result: A.precatorius ethylacetate (APEA) soluble fraction of leaves produced a significant acquisition, retention and retrieval at dosed 150 and 300 mg/kg in interoceptive as well as exteroceptive memory models of rodents. While A.precatorius aqueous fraction (APAqs) of methanol extract not enhances both the acquisition as well as the retention of memory of learned task when administered at a dose of 300 mg/kg for a period of 7 days. It was found that APEA fraction potentially inhibits AChE with percentage inhibition of 91.33±0.33. Furthermore, both fraction were found safe with no deaths in mice treated orally with 2000 mg/kg. Conclusion: APEA showed to be a useful memory restorative agent in the treatment of dementia from the experiments performed. Keywords: Abrus precatorius, Piracetam, Scopolamine, Dementi

    Exploring possibilities of enhancing water use efficiency in potato: A review

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    Climate change threatens the global agriculture sustainability. Among different kinds of abiotic stresses, water stress is the most devastating component which curtails potato crop productivity. Our recent knowledge is limited concerning water stress tolerance and water use efficiency in potato. Many efforts are being made by the scientific community to reduce water use and to produce “more crop per drop”. This review elaborates quantitative and qualitative aspects of multiple stress mechanisms and their regulating system related to present scenario of water use efficiency (WUE) requirements. WUE can only be improved by using multidisciplinary promising research approaches like molecular breeding, high throughput genotyping, multi-gene transfer and bioinformatics applications to unleash the information needed to exploitation of required traits in potato

    Mechanism of Activation and Inhibition of the HER4/ErbB4 Kinase

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    SummaryHER4/ErbB4 is a ubiquitously expressed member of the EGF/ErbB family of receptor tyrosine kinases that is essential for normal development of the heart, nervous system, and mammary gland. We report here crystal structures of the ErbB4 kinase domain in active and lapatinib-inhibited forms. Active ErbB4 kinase adopts an asymmetric dimer conformation essentially identical to that observed to be important for activation of the EGF receptor/ErbB1 kinase. Mutagenesis studies of intact ErbB4 in Ba/F3 cells confirm the importance of this asymmetric dimer for activation of intact ErbB4. Lapatinib binds to an inactive form of the ErbB4 kinase in a mode equivalent to its interaction with the EGF receptor. All ErbB4 residues contacted by lapatinib are conserved in the EGF receptor and HER2/ErbB2, which lapatinib also targets. These results demonstrate that key elements of kinase activation and inhibition are conserved among ErbB family members

    Khesari (Lathyrus sativus L.), an ancient legume for future gain: An expedition collection from parts of West Bengal state of Eastern India

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    395-403Grasspea is one of the staple foods of the local people living in the eastern parts of India. An expedition was undertaken during March, 2020 to collect germplasm of grasspea in the lower-Gangetic riverine belt and coastal areas of West Bengal of eastern India lying between latitude 21.43-24.44°N and longitude 87.23-88.90°E. From the results of a structured questionnaire administered to grasspea farmers in 57 villages located in 96 local government areas, it appeared that grasspea is the primary winter pulse cultivated in this region. Large variability of germplasm exist, ranging from small to bold seed, early to late maturing types, moderate to the high biomass type of grasspea. Most of these landraces have been adopted over the years from neighbouring communities, but in a few instances, the varietal replacement was noted, which came either through the involvement of government departments or local seed dealers. The highest proportion of the accessions (52.38%) was collected from the Purba Medinipur district, and the lowest (19.05%) was from Paschim Medinipur. On-spot evaluation of morphological traits, variations was detected in the descriptor characteristics across the locations. A total of 21 accessions was collected and assessed on-spot for different characters, viz., the seed's size, shape, seed colour, taste and texture revealed significant variation. The implications of this survey results for grasspea improvement in India are discussed in the present study

    Detection of Pancreatic Carcinomas by Imaging Lactose-Binding Protein Expression in Peritumoral Pancreas Using [18F]Fluoroethyl-Deoxylactose PET/CT

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    BACKGROUND: Early diagnosis of pancreatic carcinoma with highly sensitive diagnostic imaging methods could save lives of many thousands of patients, because early detection increases resectability and survival rates. Current non-invasive diagnostic imaging techniques have inadequate resolution and sensitivity for detection of small size ( approximately 2-3 mm) early pancreatic carcinoma lesions. Therefore, we have assessed the efficacy of positron emission tomography and computer tomography (PET/CT) imaging with beta-O-D-galactopyranosyl-(1,4')-2'-deoxy-2'-[(18)F]fluoroethyl-D-glucopyranose ([(18)F]FEDL) for detection of less than 3 mm orthotopic xenografts of L3.6pl pancreatic carcinomas in mice. [(18)F]FEDL is a novel radioligand of hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), which is overexpressed in peritumoral pancreatic acinar cells. METHODOLOGY/PRINCIPAL FINDINGS: Dynamic PET/CT imaging demonstrated rapid accumulation of [(18)F]FEDL in peritumoral pancreatic tissue (4.04+/-2.06%ID/g), bi-exponential blood clearance with half-lives of 1.65+/-0.50 min and 14.14+/-3.60 min, and rapid elimination from other organs and tissues, predominantly by renal clearance. Using model-independent graphical analysis of dynamic PET data, the average distribution volume ratio (DVR) for [(18)F]FEDL in peritumoral pancreatic tissue was estimated as 3.57+/-0.60 and 0.94+/-0.72 in sham-operated control pancreas. Comparative analysis of quantitative autoradiographic images and densitometry of immunohistochemically stained and co-registered adjacent tissue sections demonstrated a strong linear correlation between the magnitude of [(18)F]FEDL binding and HIP/PAP expression in corresponding regions (r = 0.88). The in situ analysis demonstrated that at least a 2-4 fold apparent lesion size amplification was achieved for submillimeter tumors and to nearly half a murine pancreas for tumors larger than 3 mm. CONCLUSION/SIGNIFICANCE: We have demonstrated the feasibility of detection of early pancreatic tumors by non-invasive imaging with [(18)F]FEDL PET/CT of tumor biomarker HIP/PAP over-expressed in peritumoral pancreatic tissue. Non-invasive non-invasive detection of early pancreatic carcinomas with [(18)F]FEDL PET/CT imaging should aid the guidance of biopsies and additional imaging procedures, facilitate the resectability and improve the overall prognosis

    Imatinib Inhibits GH Secretion From Somatotropinomas

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    Background: Imatinib, a tyrosine kinase inhibitor, causes growth failure in children with chronic myeloid leukemia probably by targeting the growth hormone (GH)/insulin like growth factor-1 (IGF-1) axis. We aim to explore the imatinib targets expression in pituitary adenomas and study the effect of imatinib on GH secretion in somatotropinoma cells and GH3 cell line.Materials and Methods: The expression pattern of imatinib's targets (c-kit, VEGF, and PDGFR-α/β) was studied using immunohistochemistry and immunoblotting 157 giant (≥4 cm) pituitary adenomas (121 non-functioning pituitary adenomas, 32 somatotropinomas, and four prolactinomas) and compared to normal pituitary (n = 4) obtained at autopsy. The effect imatinib on GH secretion, cell viability, immunohistochemistry, electron microscopy, and apoptosis was studied in primary culture of human somatotropinomas (n = 20) and in rat somato-mammotroph GH3 cell-line. A receptor tyrosine kinase array was applied to human samples to identify altered pathways.Results: Somatotropinomas showed significantly higher immunopositivity for c-kit and platelet-derived growth factor receptor-β (PDGFR-β; P < 0.009 and P < 0.001, respectively), while staining for platelet-derived growth factor receptor-α (PDGFR-α) and vascular endothelial growth factor (VEGF) revealed a weaker expression (P < 0.001) compared to normal pituitary. Imatinib inhibited GH secretion from both primary culture (P < 0.01) and GH3 cells (P < 0.001), while it did not affect cell viability and apoptosis. The receptor tyrosine kinase array showed that imatinib inhibits GH signaling via PDGFR-β pathway.Conclusion: Imatinib inhibits GH secretion in somatotropinoma cells without affecting cell viability and may be used as an adjunct therapy for treating GH secreting pituitary adenomas

    Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

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    We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe
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