364 research outputs found

    Antimicrobial Activity and Quantum Chemical Calculations of Pyrazol-2,3-Dihydrothiazole Sugar Derivatives

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    A number of new [(pyrazol-4-yl) methylene] hydrazono-2,3-dihydrothiazoles, sugar hydrazones, and their N-glycoside derivatives were synthesized. The chemical structures of the synthesized compounds were confirmed by 1H NMR technique. The newly synthesized compounds were tested for their antimicrobial activities and showed moderate to high inhibition activities. Quantum chemistry calculations were used to study the molecular geometry and electronic structure of the selected derivatives. The energy gap between the highest occupied molecular orbital (HOMO)and lowest unoccupied molecular orbital (LUMO) has been calculated using the theoretical computations to reflect the chemical reactivity and kinetic stability of compounds. Keywords: 1H-pyrazole, aminothiazole, ethylchloroacetate, quantum chemical calculations, antimicrobial activity

    Heme oxygenase effect on mesenchymal stem cells action on experimental Alzheimer's disease

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    The objective is to evaluate the effect of heme oxygenase-1 (HO-1) enzyme inducer and inhibitor on Mesenchymal Stem Cells (MSCs) in Alzheimer disease. Materials and Methods: 70 female albino rats were divided equally into 7 groups as follows: group 1: healthy control; group 2: Aluminium chloride induced Alzheimer disease; group 3: induced Alzheimer rats that received intravenous injection of MSCs; group 4: induced Alzheimer rats that received MSCs and HO inducer cobalt protoporphyrin; group 5: induced Alzheimer rats that received MSCs and HO inhibitor zinc protoporphyrin; group 6: induced Alzheimer rats that received HO inducer; group7: induced Alzheimer rats that received HO inhibitor. Brain tissue was collected for HO-1, seladin-1 gene expression by real time polymerase chain reaction, heme oxygenase activity, cholesterol estimation and histopathological examination. Results: MSCs decreased the plaque lesions, heme oxygenase induction with stem cells also decreased plaque lesions however there was hemorrhage in the brain. Both heme oxygenase inducer alone or with stem cells increased seladin-1 expression and decreased cholesterol level. Conclusion: MSCs alone or with HO-1 induction exert a therapeutic effect against the brain lesion in Alzheimer’s disease possibly through decreasing the brain cholesterol level and increasing seladin-1 gene expression

    Basal-like breast cancers: the phenotypic disparity between the cancer-initiating cells and tumor histology

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    Recent evidence suggests that a rare-cell population with a stem cell phenotype maintains breast tumors. Therefore, to devise breast cancer therapies that are more effective, we need to understand the unique biology of these cancer stem cells. Currently, very little is known about the origin of cancer stem cells and their relationship to the tumor phenotype. A recent study from Smalley's group demonstrates that targeting an inactivating Brca1 mutation to the luminal progenitors could yield basal-like breast cancers. This observation suggests that the inherent plasticity of the primitive cells can be hijacked by the tumorigenic processes to produce tumors with an unpredictable phenotype

    The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. I. Survey Overview and First Results for Andromeda I

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    An optical monitoring survey in nearby dwarf galaxies was carried out with the 2.5 m Isaac Newton Telescope. Fifty-five dwarf galaxies and four isolated globular clusters in the Local Group were observed with the Wide Field Camera. The main aims of this survey are to identify the most evolved asymptotic giant branch (AGB) stars and red supergiants at the end-point of their evolution based on their pulsational instability, use their distribution over luminosity to reconstruct the star formation history, quantify the dust production and mass loss from modeling the multiwavelength spectral energy distributions (SEDs), and relate this to luminosity and radius variations. In this first of a series of papers, we present the methodology of the variability survey and describe the photometric catalog of the Andromeda I (And I) dwarf galaxy as an example of the survey, and we discuss the identified long period variable (LPV) stars. We detected 5581 stars and identified 59 LPV candidates within two half-light radii of the center of And I. The amplitudes of these candidates range from 0.2 to 3 mag in the i-band. Seventy-five percent of detected sources and 98% of LPV candidates are detected at mid-infrared wavelengths. We show evidence for the presence of dust-producing AGB stars in this galaxy including five extreme AGB (x-AGB) stars, and we model some of their SEDs. A distance modulus of 24.41 mag for And I was determined based on the tip of the red giant branch. Also, a half-light radius of 3.′2 ± 0.′3 was calculated

    Analyzing the Influence of Design and Operating Conditions on Combustion and Emissions in Premixed Turbulent Flames: A Comprehensive Review

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    Recently, premixed combustion has dominated the field of combustion research worldwide. The current work is a review that addresses the effects of design and operating regimes on the combustion and emission characteristics of premixed turbulent flames. The study accounts for recent developments aimed at overcoming combustor operability issues that influence emissions and flame stability. Various experimental setups have been utilized in investigations, with results pertaining to performance and emissions concerning premixed turbulent flames. Thus, the objective of this paper is to provide a comprehensive review of the effects of swirl vane angles and equivalence fuel-air ratios for tests conducted both with and without secondary air, aiming to improve combustion performance and reduce emissions. This review extensively analyzes published studies to provide and discuss different strategies for controlling premixed turbulent combustion techniques within a wide range of swirl vane angles and equivalence air-fuel ratios

    Identification and Characterization of AES-135, a Hydroxamic Acid-Based HDAC Inhibitor That Prolongs Survival in an Orthotopic Mouse Model of Pancreatic Cancer

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    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive, incurable cancer with a 20% 1 year survival rate. While standard-of-care therapy can prolong life in a small fraction of cases, PDAC is inherently resistant to current treatments, and novel therapies are urgently required. Histone deacetylase (HDAC) inhibitors are effective in killing pancreatic cancer cells in in vitro PDAC studies, and although there are a few clinical studies investigating combination therapy including HDAC inhibitors, no HDAC drug or combination therapy with an HDAC drug has been approved for the treatment of PDAC. We developed an inhibitor of HDACs, AES-135, that exhibits nanomolar inhibitory activity against HDAC3, HDAC6, and HDAC11 in biochemical assays. In a three-dimensional coculture model, AES-135 kills low-passage patient-derived tumor spheroids selectively over surrounding cancer-associated fibroblasts and has excellent pharmacokinetic properties in vivo. In an orthotopic murine model of pancreatic cancer, AES-135 prolongs survival significantly, therefore representing a candidate for further preclinical testing

    Experimental Study on the Impact of Secondary Air Injection and different swirl van angles on Premixed Turbulent Flame Propagation and Emission Behaviors

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    The objective of the present paper is to investigate experimentally the flame characteristics utilizing different secondary air inlet direction for different primary air swirl numbers and equivalence fuel-air ratios. In this study, an experimental test rig was carried out to investigate the flame temperature and emission behavior with flame length at the equivalence fuel-air ratios taken0.96, 0.80, 0.70, and 0.60, and swirl vane angles were varied as 20, 30, 45, and 60° to generate different swirl numbers of 0.26, 0.416, 0.71 and 1.23, respectively. In addition to the introduction of secondary air in test combustor, whereas the primary air and fuel mass flow rates were kept constant at 12.5. Also, the secondary air flow rate was changed to give different secondary over primary air and fuel ratios of 0.19, 0.32, 0.41, and 0.48. The study showed that the flame temperature distribution with flame length at the equivalence fuel-air ratios is increased at 20.0 mm of radial flame distance and decreases gradually with radial flame distance. Also, the experimental investigation illustrated the emission characteristics at different equivalence fuel-air ratios accounting for nitrogen oxide and unburned hydrocarbon were decreased gradually with radial flame distance at different swirl vane angles. Moreover, the emission characteristics at different equivalence fuel-air ratios accounting for the concentration percent of carbon dioxide and carbon monoxide were decreased gradually with radial flame distance at different swirl vane angle

    Effects of Fuel Equivalence Ratio and Swirl Vane Angles on Premixed Burner Turbulent Flame Combustion Characteristics

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    A turbulent flow field has a major effect on the premixed flame structure and temperature distribution that specifically determines the effectiveness of the burned fuel and the amounts of produced emissions. However, the premixed flame tangential and axial velocity distribution through the flame length help to predict the combustion and emissions attributes of the burned fuel. In this regard, an experimental and analytical investigation on premixed turbulent burners at different equivalence fuel-air ratios with different swirl vane angles has been achieved in the present work to assess the combustion performance and emissions characteristics. A theoretical methodology was carried out to predict the flame temperature distribution with flame length at the equivalence fuel-air ratio of 0.6 and 0.8and swirl vane angle 20°. Also, the emission characteristics such as NOx, CO2, CO, and UHC have accounted experimentally and analytically to accounting gas temperature, and axial and tangential velocities distribution along the flame length. However, a statistical analysis was performed to verify and validate the proposed model. The prediction and experimental observations illustrated the acceptable agreement whereas the overall error in the experimental testes verification is about 3.66 %
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