651 research outputs found

    Ab-initio insights into the structural, elastic, bonding, and thermophysical properties of UHx (x = 1, 2, 3, 5, 6, 7, 8) under pressure: possible relevance to high-Tc superconductivity

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    Binary uranium hydrides, UHx (x = 1, 2, 3, 5, 6, 7, 8), with different crystal symmetries are potentially interesting compounds for high-Tc superconductivity and as hydrogen storage systems. In this work we have explored the structural, elastic, mechanical, bonding, and thermophysical properties of these systems under uniform pressure via density functional theory based computations. Most of the results disclosed in this work are novel. From the calculations of the cohesive energy and enthalpy of formation, we have found that the titled compounds are chemically stable. The computed elastic constants at different pressures ensure elastic stability. All the binary hydrides are mechanically anisotropic. Pressure induced brittle-ductile transition takes place under high pressure. The compounds are machinable with the cubic {\alpha}-UH3-Pm-3n showing very high value of the machinability index. All the compounds are fairly hard with cubic UH8 showing superhard character. The Debye temperatures and acoustic velocities of these compounds are high; the highest value is found for the cubic UH8. The melting temperature, Gr\"uneisen parameter, minimal phonon thermal conductivity, and the thermal expansion coefficient of these compounds have also been studied at different pressures. All these parameters show excellent correspondence with the estimated Debye temperature, elastic parameters and bonding characteristics

    Molecular Basis of Triple Negative Breast Cancer and Implications for Therapy

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    Triple negative breast cancer is an aggressive form of breast cancer with limited treatment options and is without proven targeted therapy. Understanding the molecular basis of triple negative breast cancer is crucial for effective new drug development. Recent genomewide gene expression and DNA sequencing studies indicate that this cancer type is composed of a molecularly heterogeneous group of diseases that carry multiple somatic mutations and genomic structural changes. These findings have implications for therapeutic target identification and the design of future clinical trials for this aggressive group of breast cancer

    First-principles pressure dependent investigation of the physical properties of KB2H8: a prospective high-TC superconductor

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    Using the density functional theory (DFT) based first-principles investigation, the structural, mechanical, hardness, elastic anisotropy, optoelectronic, and thermal properties of cubic KB2H8 have been studied within the uniform pressure range of 0 - 24 GPa. The calculated structural parameters are in good agreement with the previous theoretical work. The compound KB2H8 is found to be structurally and thermodynamically stable in the pressure range from 8 GPa to 24 GPa. Single crystal elastic constants Cij and bulk elastic moduli (B, G and Y) increase systematically with pressure from 8 GPa to 24 GPa. In the stable phase, KB2H8 is moderately elastically anisotropic and ductile in nature. The compound is highly machinable and fracture resistant. The Debye temperature, melting temperature and thermal conductivity increases with pressure. The results of electronic band structure calculations and optical parameters at different pressures are consistent with each other. The compound is optically isotropic. The compound KB2H8 has potential to be used as a very efficient solar energy reflector. The electronic energy density of states at the Fermi level decreases systematically with increasing pressure. The same trend is found for the repulsive Coulomb pseudopotential. Possible relevance of the studied properties to superconductivity has also been discussed in this paper

    Nab-paclitaxel monotherapy in refractory pancreatic adenocarcinoma

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    BACKGROUND: The standard of care in patients with metastatic pancreatic adenocarcinoma is undefined beyond second line of treatment. There have been scant reports of benefit from nab-paclitaxel in patients with refractory pancreatic cancer. MATERIALS AND METHODS: A retrospective review was carried out in patients with pancreatic adenocarcinoma at Siteman Cancer Center, who had received nab-paclitaxel monotherapy after experiencing disease progression on standard treatments. Nab-paclitaxel was given either two out of every three weeks or three out of every four weeks. RESULTS: Twenty patients were identified and included for data analysis. Median age was 63.5 years old. All patients had previously received gemcitabine, while 40% had also received FOLFIRINOX. Median number of prior lines of systemic treatment was 2. Patients were treated for a median of 15 weeks, with a range of 1 to 41.7 weeks. Median dose of nab-paclitaxel was 100 mg/m(2) with range of 75-125 mg/m(2). Best response imaging was available in 17 patients and 11 out of the 17 patients (64.7%) had stable disease. Median progression-free survival (PFS) was 3.7 months and overall survival (OS) were 5.2 months. Most common treatment related toxicities included grade 1 pneumonitis in five patients (25%), grade 3 or 4 neutropenia in three patients (15%), and dehydration resulting in hospitalization in one patient (5%). CONCLUSIONS: Nab-paclitaxel monotherapy had acceptable level of toxicity in a heavily pretreated patient population with pancreatic cancer and appeared to provide a clinical benefit. This agent is worthy of further prospective studies to evaluate extent of benefit after standard therapies have failed
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