110 research outputs found

    DEVELOPMENT AND VALIDATION OF UV SPECTROPHOTOMETRIC AND REVERSED PHASE‑HIGH PERFORMANCE LIQUID CHROMATOGRAPHY ‑ PDA METHODS FOR THE ESTIMATION OF ALOGLIPTIN BENZOATE

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    Objective: To develop and validate simple, rapid, precise, accurate, and economical UV spectrophotometric and reverse phase high performanceliquid chromatographic methods for the estimation of alogliptin benzoate (AGP).Methods: UV spectrophotometric method was performed using UV/Vis double beam spectrophotometer with a spectral bandwidth of 1 nm and1.0 cm matched quartz cells. The maximum absorbance of AGP was observed at 276 nm using methanol as solvent. Reversed phase-high performanceliquid chromatography (RP-HPLC) method was carried out on a Unisol reverse phase C18 column (150 mm × 4.6 mm, 3 μm) with a mobile phasecomposed of methanol and 10 mM ammonium acetate buffer (adjusted to pH 5.0 with glacial acetic acid) in the ratio of 80:20 v/v with a flow rate of0.8 ml/minutes.Results: The linearity of methods was found to be in the range of 5-35 µg/ml (UV) and 20-100 µg/ml (RP-HPLC) and the correlation coefficient was0.999 for both the methods. The regression equations were y = 0.028x + 0.023 (UV) and y = 28,58,942x - 4,33,647 (HPLC). The retention time of AGPwas 2.37 minutes.Conclusion: The proposed methods were validated in terms of linearity, precision, accuracy, specificity, robustness, limit of detection, and limit ofquantitation as per International Conference on Harmonization Q2 R1 guidelines. Thus, the proposed methods are novel, sensitive, and reliable andcan be successfully used for the quantitation of AGP.Keywords: Alogliptin benzoate, UV-visible spectrophotometer, Reversed phase-high performance liquid chromatography, International Conferenceon Harmonization guidelines

    DEVELOPMENT AND VALIDATION OF STABILITY INDICATING REVERSE PHASE HIGH‑PERFORMANCE LIQUID CHROMATOGRAPHIC METHOD FOR THE ESTIMATION OF PIRIBEDIL IN BULK DRUG

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    ABSTRACTObjective: A simple, precise, fast, economic, accurate, robust, and stability indicating isocratic reverse phase high-performance liquid chromatographicmethod was developed for the analysis of Piribedil.Method: The chromatographic conditions were standardized using Unisol C-18 (4.6 × 150 mm × 3.0 μ) column with UV detection at 244 nm, and themobile phase composed of methanol:acetate buffer-pH 5.0 (85:15, v/v).Results: The retention time of Piribedil was found to be 3.4 minutes. The calibration curve was linear with correlation coefficient of 0.999 over aconcentration range of 20-100 μg/ml with linear regression equationy=74,69,224.37x−39,46,924.90. The limit of detection and limit of quantitationwere found to be 0.04 and 0.4 μg/ml, respectively.Conclusion: The proposed method has been validated according to the ICH guidelines. Piribedil was subjected to stress conditions includingacidic, alkaline, oxidation, photolysis, and thermal degradation. Piribedil is more sensitive to photolytic stress. There are no interfering peaks fromdegradation products at analyte retention time, and thus the method is specific for the estimation of Piribedil in the presence of degradation products.Thus, the proposed method can be successfully applied in the routine quality control and stability samples of Piribedil in bulk drug.Keywords: Piribedil, Validation, Stability indicating, Reverse phase high-performance liquid chromatographic

    Phase Transition in the Takayasu Model with Desorption

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    We study a lattice model where particles carrying different masses diffuse, coalesce upon contact, and also unit masses adsorb to a site with rate qq or desorb from a site with nonzero mass with rate pp. In the limit p=0p=0 (without desorption), our model reduces to the well studied Takayasu model where the steady-state single site mass distribution has a power law tail P(m)mτP(m)\sim m^{-\tau} for large mass. We show that varying the desorption rate pp induces a nonequilibrium phase transition in all dimensions. For fixed qq, there is a critical pc(q)p_c(q) such that if p<pc(q)p<p_c(q), the steady state mass distribution, P(m)mτP(m)\sim m^{-\tau} for large mm as in the Takayasu case. For p=pc(q)p=p_c(q), we find P(m)mτcP(m)\sim m^{-\tau_c} where τc\tau_c is a new exponent, while for p>pc(q)p>p_c(q), P(m)exp(m/m)P(m)\sim \exp(-m/m^*) for large mm. The model is studied analytically within a mean field theory and numerically in one dimension.Comment: RevTex, 11 pages including 5 figures, submitted to Phys. Rev.

    Buckwheat: Potential Stress-Tolerant Crop for Mid-Hills of Eastern Himalaya under Changing Climate

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    Under changing climate, identification and diversification of cropping systems having higher stress resilience and adaptability for fragile mountain ecosystems of Eastern Himalayan Region (EHR) are paramount. Lesser known and underutilized crop like buckwheat (BW) with year-round cultivation potential and having higher stress tolerance to prevailing stresses (low pH, low moisture) could be a crop of choice for abating malnutrition among hill inhabitants. Proper time of sowing of the crop is between mid-September and mid-December seemingly essential for better grain yield to the tune of 15.0–18.0 q ha−1, and the crop is found suitable to be grown all through the year for higher green biomass (12.6–38.4 q ha−1). Enhanced exudation of low-molecular-weight organic acids (LMWOA) like oxalic acid by buckwheat increased the solubilization of fixed forms of free phosphorus (P) to the extent of 35.0 to 50.0 micro gram per plant in ideal acid soil of the region (P) in acid soil. In addition, relatively increased resilience to moisture stress with improved stress physiological attributes adds more potentiality for enhancing cropping intensity of hill slopes of EHR. Few genotypes namely IC377275 (18.97q ha−1), IC26591 (17.1 qt ha−1), IC14890 (16.32q ha−1), and Himapriya (15.27q ha−1) are emerging as high-yielding types for productive cultivation in acid soils. Studies on the combined effects of acid soil and moisture stress would aid in novel crop improvement of buckwheat in EHR

    Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

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    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

    Estrogen/progesterone Receptor and HER2 Discordance Between Primary Tumor and Brain Metastases in Breast Cancer and Its Effect on Treatment and Survival

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    BACKGROUND: Breast cancer treatment is based on estrogen receptors (ERs), progesterone receptors (PRs), and human epidermal growth factor receptor 2 (HER2). At the time of metastasis, receptor status can be discordant from that at initial diagnosis. The purpose of this study was to determine the incidence of discordance and its effect on survival and subsequent treatment in patients with breast cancer brain metastases (BCBM). METHODS: A retrospective database of 316 patients who underwent craniotomy for BCBM between 2006 and 2017 was created. Discordance was considered present if the ER, PR, or HER2 status differed between the primary tumor and the BCBM. RESULTS: The overall receptor discordance rate was 132/316 (42%), and the subtype discordance rate was 100/316 (32%). Hormone receptors (HR, either ER or PR) were gained in 40/160 (25%) patients with HR-negative primary tumors. HER2 was gained in 22/173 (13%) patients with HER2-negative primary tumors. Subsequent treatment was not adjusted for most patients who gained receptors-nonetheless, median survival (MS) improved but did not reach statistical significance (HR, 17-28 mo, P = 0.12; HER2, 15-19 mo, P = 0.39). MS for patients who lost receptors was worse (HR, 27-18 mo, P = 0.02; HER2, 30-18 mo, P = 0.08). CONCLUSIONS: Receptor discordance between primary tumor and BCBM is common, adversely affects survival if receptors are lost, and represents a missed opportunity for use of effective treatments if receptors are gained. Receptor analysis of BCBM is indicated when clinically appropriate. Treatment should be adjusted accordingly. KEY POINTS: 1. Receptor discordance alters subtype in 32% of BCBM patients.2. The frequency of receptor gain for HR and HER2 was 25% and 13%, respectively.3. If receptors are lost, survival suffers. If receptors are gained, consider targeted treatment

    Search for long-lived, massive particles in events with displaced vertices and multiple jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    A search for long-lived particles decaying into hadrons is presented. The analysis uses 139 fb−1 of pp collision data collected at √s = 13 TeV by the ATLAS detector at the LHC using events that contain multiple energetic jets and a displaced vertex. The search employs dedicated reconstruction techniques that significantly increase the sensitivity to long-lived particles decaying in the ATLAS inner detector. Background estimates for Standard Model processes and instrumental effects are extracted from data. The observed event yields are compatible with those expected from background processes. The results are used to set limits at 95% confidence level on model-independent cross sections for processes beyond the Standard Model, and on scenarios with pair-production of supersymmetric particles with long-lived electroweakinos that decay via a small R-parity-violating coupling. The pair-production of electroweakinos with masses below 1.5 TeV is excluded for mean proper lifetimes in the range from 0.03 ns to 1 ns. When produced in the decay of m(g∼) = 2.4 TeV gluinos, electroweakinos with m(χ∼01) = 1.5 TeV are excluded with lifetimes in the range of 0.02 ns to 4 ns
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