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101.
Synthetic and Biological Studies of Sesquiterpene Polygodial: Activity of 9‐Epipolygodial against Drug‐Resistant Cancer Cells
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Dr. Ramesh Dasari Annelise De Carvalho Derek C. Medellin Kelsey N. Middleton Dr. Frédéric Hague Marie N. M. Volmar Prof. Liliya V. Frolova Dr. Mateus F. Rossato Jorge J. De La Chapa Nicholas F. Dybdal‐Hargreaves Akshita Pillai Prof. Véronique Mathieu Prof. Snezna Rogelj Prof. Cara B. Gonzales Prof. João B. Calixto Prof. Antonio Evidente Dr. Mathieu Gautier Dr. Gnanasekar Munirathinam Prof. Rainer Glass Prof. Patricia Burth Dr. Stephen C. Pelly Prof. Willem A. L. van Otterlo Prof. Robert Kiss Prof. Alexander Kornienko 《ChemMedChem》2015,10(12):2014-2026
Polygodial, a terpenoid dialdehyde isolated from Polygonum hydropiper L., is a known agonist of the transient receptor potential vanilloid 1 (TRPV1). In this investigation a series of polygodial analogues were prepared and investigated for TRPV1‐agonist and anticancer activities. These experiments led to the identification of 9‐epipolygodial, which has antiproliferative potency significantly exceeding that of polygodial. 9‐Epipolygodial was found to maintain potency against apoptosis‐resistant cancer cells as well as those displaying the multidrug‐resistant (MDR) phenotype. In addition, the chemical feasibility for the previously proposed mechanism of action of polygodial, involving the formation of a Paal–Knorr pyrrole with a lysine residue on the target protein, was demonstrated by the synthesis of a stable polygodial pyrrole derivative. These studies reveal rich chemical and biological properties associated with polygodial and its direct derivatives. These compounds should inspire further work in this area aimed at the development of new pharmacological agents, or the exploration of novel mechanisms of covalent modification of biological molecules with natural products. 相似文献
102.
Cross-talk between the sympathetic nervous system (SNS) and immune system is vital for health and well-being. Infection, tissue injury and inflammation raise firing rates of sympathetic nerves, increasing their release of norepinephrine (NE) in lymphoid organs and tissues. NE stimulation of β2-adrenergic receptors (ARs) in immune cells activates the cAMP-protein kinase A (PKA) intracellular signaling pathway, a pathway that interfaces with other signaling pathways that regulate proliferation, differentiation, maturation and effector functions in immune cells. Immune–SNS cross-talk is required to maintain homeostasis under normal conditions, to develop an immune response of appropriate magnitude after injury or immune challenge, and subsequently restore homeostasis. Typically, β2-AR-induced cAMP is immunosuppressive. However, many studies report actions of β2-AR stimulation in immune cells that are inconsistent with typical cAMP–PKA signal transduction. Research during the last decade in non-immune organs, has unveiled novel alternative signaling mechanisms induced by β2-AR activation, such as a signaling switch from cAMP–PKA to mitogen-activated protein kinase (MAPK) pathways. If alternative signaling occurs in immune cells, it may explain inconsistent findings of sympathetic regulation of immune function. Here, we review β2-AR signaling, assess the available evidence for alternative signaling in immune cells, and provide insight into the circumstances necessary for “signal switching” in immune cells. 相似文献
103.
Denise Loder Susanne Katharina Michelic Christian Bernhard 《BHM Berg- und Hüttenm?nnische Monatshefte》2016,161(7):315-320
The formation of acicular ferrite is mainly influenced by the steel composition, cooling rate, austenite grain size, and inclusion landscape. However, their precise effects have not been clarified in literature yet. Within the FWF project TRP 266-N19, a systematic methodology to study the influencing factors of the acicular ferrite formation as well as their interactions on laboratory scale was developed. The present work exemplarily demonstrates the application of this methodology for studying the effect of cooling rate and boron on the formation of acicular ferrite in a low-carbon HSLA steel. 相似文献
104.
Juliana Mendes de Oliveira Iara Alves Anes Jorge Luís Coleti Denise Crocce Romano Espinosa Marcelo Siqueira de Carvalho Jorge Alberto Soares Tenório 《加拿大化工杂志》2023,101(4):1743-1761
Niobium (Nb) and Tantalum (Ta) are used to increase materials' mechanical resistance and produce lighter alloys. Worldwide Nb production reached 78 000 t in 2020. The reduced ore offer justifies the recycling of these metals from tin slag, contributing to the circular economy. Nb2O5 and Ta2O5 extraction either from the primary source or the tin slag is an industrial challenge. Nb and Ta dissolution processes already implemented are fluoride leaching, sulphuric leaching, alkaline leaching, and alkaline roasting. The fluoride process raises environmental concerns about waste control. The sulphuric method can be managed to have higher Nb and Ta extraction in a less aggressive process, if some changes are implemented, such as increasing the number of extraction steps, decreasing the pulp density, or increasing the temperature; however, the efficiency of this methodology must be tested for tin slag. The alkaline method seems to be more selective to Nb and Ta by reactants and temperature control. Despite those well-established Nb and Ta treatments, they must be adapted to recover Nb and Ta from slag. The slag has low Nb and Ta content, while high Si and Ca concentrations exist in the matrix. This paper brings the main methods used to extract the Nb and Ta from the primary resources and an overview of Nb and Ta recovery from the slag. This investigation comes as a tool to guide the development of new methods to recover Nb and Ta from low-grade sources such as tin slag. 相似文献
105.
Ehbenezer C. Uys Cara E. SchwarzAndries J. Burger Johannes H. Knoetze 《Chemical Engineering Research and Design》2012
A thorough understanding of the hydrodynamics in tray columns is required to optimise column and tray design for specific operating capacities and conditions. Liquid transported by the rising gas to the tray above, defined as entrainment, is one way of measuring the tray column capacity limit. Entrainment correlations available in the literature have been developed with predominantly air/water data, because of the limited availability of non-air/water data. In this work an experimental setup was constructed to measure entrainment, tray pressure drop and weeping for various gas and liquid systems. The experimental entrainment data for three systems, namely air/water, air/ethylene glycol and air/silicone oil, is compared to existing correlations. The effect of liquid physical properties on entrainment under flow factors ranging from 1.6 kg0.5/(m0.5 s), for a 415 mm tray spacing to 4.0 kg0.5/(m0.5 s) for a 615 mm tray spacing within a liquid flow range of 2.9–112 m3/(h m) was observed. The experimental results showed a somewhat complex dependency of entrainment on liquid physical properties. At gas flow factors of 2.2 kg0.5/(m0.5 s) for the 415 mm tray spacing, entrainment reached a maximum in the froth regime and then decreased with increasing liquid rates. Notably, the liquid viscosity – not included in previously developed correlations – significantly influences the entrainment behaviour. Existing entrainment correlations agree better with the air/water data than with the air/ethylene glycol or air/silicone oil data. 相似文献
106.
This article describes the need for psychologists working with persons with disabilities to establish validity procedures within research findings and clinical practices. It highlights the importance of providing a contextual framework for behavior by adopting a socioecological paradigm of disability. Theoretical, research, and clinical practice implications are discussed, such as the evolution of paradigms guiding rehabilitation, the need to move research out of the laboratories and into the field, and the importance of focusing on the broader socioenvironmental needs of persons with disabilities. The author also offers specific recommendations for psychologists engaged in activities across education, research, and clinical practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
107.
This study investigated age, cognitive abilities, health beliefs, and other factors in women's judgments about effective treatments for menopause. Women (N?=?102) ranging in age from 20 to 79 read a vignette about a woman facing a decision about Estrogen Replacement Therapy (ERT) and then made judgments about what should be done. Participants also completed a battery of questions pertaining to ERT and cognitive abilities. Path-analytic techniques were used to determine the role of specific cognitive abilities and the representation of menopause and its treatment in making judgments about ERT treatments. Cognitive abilities had direct effects on treatment decisions. Education affected the number of perceived options for treatment. Age and education indirectly affected treatment decisions, operating through cognitive abilities. Factors related to the mental representation of menopause had no direct effects and few indirect effects on treatment decisions. Potential mechanisms that can help older adults compensate for declines in cognitive abilities in medical decisions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
This meta-analysis addressed the question of how effective grief therapy is and for whom, using B. J. Becker's (1988) techniques for analyzing standardized mean-change scores. Analyses were based on 35 studies (N?=?2,284), with a weighted mean effect size (ES) of δ+?=?0.43 (95% confidence interval?=?0.33 to 0.52). Clients in no-treatment control groups showed little improvement (d=?=?0.06), possibly because of the relatively long delay between loss and treatment in most studies (mean delay?=?27 months). Moderators of treatment efficacy included time since loss and relationship to the deceased. Client selection procedures, a methodological factor not originally coded in this meta-analysis, appeared to contribute strongly to variability in ESs: a small number of studies involving self-selected clients produced relatively large ESs, whereas the majority of studies involving clients recruited by the investigators produced ESs in the small to moderate range. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
The enhancement of the 1 day strength of cementitious systems by a combination of calcium chloride (CaCl2) and diethanol-isopropanolamine (DEIPA) was studied, particularly in blended cement systems. A combination of quantitative X-ray diffraction with Rietveld refinement (QXRD), scanning electron microscopy (SEM)/backscattered electron image analysis, thermogravimetric analysis (TGA), and isothermal calorimetry were used to investigate the mechanism of strength enhancement by the additives. The additives were found to increase the early age mortar strength by enhancing the cement hydration, with the DEIPA enhancing primarily the aluminate hydration. DEIPA also affected the morphology of portlandite which was formed as thin plates. In parallel, the calcium-to-silica ratio of the C-S-H was found to increase with the use of DEIPA, possibly because of the inclusion of microcrystalline portlandite. After 48 h DEIPA was found to directly enhance the rate of reaction of granulated blast-furnace slag and fly ash. 相似文献
110.
Francois Carmona Serge Flandrois Laurent Antunes Jean-Marc Heintz 《Journal of Low Temperature Physics》1999,117(3-4):783-787
We report the results of the study of the resistive transition and the screening effect on similar random composites made of a silver matrix containing sintered superconducting grains of bismuth phase with two different stoichiometries. We show that most of the observed behaviors are compatible with a phenomenological approach in which the intergrain junctions behave as weak links whose the state depends strongly on temperature and field. We find that these links a much weaker in one of the series of samples. 相似文献