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排序方式: 共有909条查询结果,搜索用时 15 毫秒
71.
Denise Abatti M. Elisabete D. Zaniquelli Yassuko Iamamoto Ynara M. Idemori 《Thin solid films》1997,310(1-2):296-302
A synthetic iron ortho-substituted tetradecylpyridyl porphyrin was used to prepare Langmuir-Blodgett films. Better spreading at the gas-liquid interface was obtained for mixed films using palmitic acid in a 1:4 proportion. The minimum area per molecule from π-A curves for the pure porphyrin monolayers is correlated to the value obtained for the flat orientation of the porphyrinic center on the water surface, as determined by the CPK model. The fatty acid causes a decrease in the porphyrin minimum area per molecule. Single monolayer LB deposition gives a monomeric film without the presence of aggregates as attested by UV-visible spectra. The film was used in the heterogeneous catalysis of cyclohexene oxidation furnishing a yield two times higher than that obtained for the homogeneous system, using the same porphyrin amount and reagent ratio. The reaction was highly selective: only cyclohexene oxide was recorded as the product, confirming that the system is a good model for cytochrome P450. 相似文献
72.
Tate Denise G.; Kewman Donald G.; Maynard Frederick 《Canadian Metallurgical Quarterly》1990,35(4):211
Explored the appropriateness of the Brief Symptom Inventory (BSI) as a measure of psychological distress among 79 traumatic spinal cord injured (SCI) patients (aged 18–70 yrs) and emphasized the limitations of using the BSI as a replacement for the SCL-90—Revised (SCL-90—R). Ss' BSI scores were compared with a nonpatient normative group (N?=?974). Ss were significantly more psychologically distressed in somatization, depression, and phobic anxiety than the normative group. However, several somatization symptoms endorsed by these Ss are common physical effects of SCI rather than psychosomatic complaints. When comparing BSI and SCL-90—R scores of the same Ss, significant statistical differences were found with respect to the level of psychological distress being reported by each test. The BSI may not represent an equivalent abbreviated form of the SCL-90—R for the SCI population. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
73.
David L. Felten Suzanne Y. Felten John R. Sladek Mary D. Notter Sonia L. Carlson Denise L. Bellinger Stanley J. Wiegand 《Journal of microscopy》1990,157(3):271-283
Formaldehyde-induced and glyoxylic-acid-induced fluorescence histochemistry permits the tissue localization of catecholamines in the central nervous system (CNS) and peripheral nervous system (PNS), and in culture. Counterstains such as ethidium bromide provide excellent background identification of specific innervated regions in both the CNS and the periphery. Use of fluorescence histochemistry with immunocytochemistry can elucidate catecholamine-peptide relationships. Gelatin-ink perfusion used with fluorescence histochemistry permits the investigation of neuro-vascular relationships and documentation of vascular and parenchymal compartmentation of innervation. Combined use of fluorescence histochemistry and retrograde tracing methods demonstrates the specific cellular sources of innervation of target regions. Micropunch neurochemical analysis provides quantitative data for correlation with fluorescence histochemistry within a target region of innervation, and micro-spectrofluorometric analysis provides a semi-quantitative evaluation of the amount of fluorophore within a target region or within specific subcellular compartments such as the cell body or terminals. 相似文献
74.
75.
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
76.
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
77.
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
78.
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
79.
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
80.
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