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131.
Ana F. Ferreira Joana Santiago Joana V. Silva Pedro F. Oliveira Margarida Fardilha 《International journal of molecular sciences》2022,23(23)
Male fertility relies on the ability of spermatozoa to fertilize the egg in the female reproductive tract (FRT). Spermatozoa acquire activated motility during epididymal maturation; however, to be capable of fertilization, they must achieve hyperactivated motility in the FRT. Extensive research found that three protein phosphatases (PPs) are crucial to sperm motility regulation, the sperm-specific protein phosphatase type 1 (PP1) isoform gamma 2 (PP1γ2), protein phosphatase type 2A (PP2A) and protein phosphatase type 2B (PP2B). Studies have reported that PP activity decreases during epididymal maturation, whereas protein kinase activity increases, which appears to be a requirement for motility acquisition. An interplay between these PPs has been extensively investigated; however, many specific interactions and some inconsistencies remain to be elucidated. The study of PPs significantly advanced following the identification of naturally occurring toxins, including calyculin A, okadaic acid, cyclosporin, endothall and deltamethrin, which are powerful and specific PP inhibitors. This review aims to overview the protein phosphorylation-dependent biochemical pathways underlying sperm motility acquisition and hyperactivation, followed by a discussion of the PP inhibitors that allowed advances in the current knowledge of these pathways. Since male infertility cases still attain alarming numbers, additional research on the topic is required, particularly using other PP inhibitors. 相似文献
132.
V. Perna E. Castelló J. Wenzel C. Zampol D.M. Fontes Lima L. Borzacconi M.B. Varesche M. Zaiat C. Etchebehere 《International Journal of Hydrogen Energy》2013
In this work, an upflow anaerobic packed bed reactor configuration to produce hydrogen using cheese whey as the substrate was tested. The microbiological composition was linked to the reactor operation. 相似文献
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135.
Bruno Campello de Souza Leonardo Xavier de Lima e Silva Antonio Roazzi 《Computers in human behavior》2010
The present paper attempts to empirically study the cognitive impacts of Massive Multiplayer Online Role-Playing Games (MMORPGs) in uncontrolled contexts in light of the Cognitive Mediation Networks Theory, a new model of human intelligence that aims to explain cognition as the result of brain activity combined with the information-processing done by external structures such as tools, social groups and culture. A sample of 1280 students Brazilian high school students answered a form inquiring about socio-demographic information plus the use of computer games, and also was submitted to a short knowledge exam and a mini psychometric test. The findings indicated that, due to their underlying structure and sociocultural nature, MMORPGs are associated to a greater level of insertion into the Digital Age, higher levels of logical-numerical performance, and better scholastic ability. Finally, suggestions are made for future studies on the subject. 相似文献
136.
Establishing quality performance of distribution companies based on yardstick regulation 总被引:1,自引:0,他引:1
This paper proposes a procedure and methodology for performance target setting related to continuity metrics in electricity distribution networks. This proposal deals with one of the key issues in the monopoly regulation, which is either the reduction of the information asymmetry among economic agents or the emulation of a competitive environment in industry segments usually considered as natural monopolies. This paper develops an approach toward standard definitions for Customer Average Interruption Duration Index (DEC) and Customer Average Interruption Frequency Index (FEC) based on inter-companies comparative analysis. This approach introduces productive efficiency concepts to the definition of network performance. In order to do so, the data envelopment analysis (DEA) technique, used for defining the efficiency frontier, was combined with the dynamic cluster technique, oriented toward models of identification of similar networks. A technique for comparative analysis was used for the definition of the network expected performance. Examples with the Brazilian electric systems are provided to clarify the methodology suggested by this paper. 相似文献
137.
Brandao Jacobina C. Beltrao de Rossiter Correa M. Nogueira Lima A.M. Cabral da Silva E.R. 《Industry Applications, IEEE Transactions on》2003,39(5):1333-1342
This paper presents two reduced-switch-count AC drive systems. One of the configurations was conceived to operate with a two-phase motor and the other one with a three-phase motor. The drive systems provide both bidirectional power flow and power factor control. Pulsewidth modulation techniques for the converter control are discussed. Experimental results are presented. 相似文献
138.
de Souza Ribeiro L.A. Jacobina C.B. Lima A.M.N. Oliveira A.C. 《Industry Applications, IEEE Transactions on》2000,36(3):743-754
This paper studies the parameter estimation of induction machines. The problems associated with the parameter estimation of induction machines are analyzed through sensitivity functions. Then, models and a procedure to estimate a set of four basic parameters (rs, σls, ls, and τr) are proposed. The discrete-time parameter estimation models are written in the δ operator specifically because it provides good numerical properties at high sampling rates, where the discrete-time model approaches its continuous-time equivalent. This feature permits the direct estimation of the continuous-time parameters. The main feature of the proposed procedure is the possibility to estimate the parameters by using sinusoidal signals, and without the measurement of the machine speed. The experimental results obtained with the proposed estimation procedure are presented and demonstrate that it is possible to map the parameters in terms of the operating conditions of the induction machine 相似文献
139.
Pedro Lima Cardoso Florian Ph. S. Fischmeister Barbara Dymerska Alexander Geißler Moritz Wurnig Siegfried Trattnig Roland Beisteiner Simon Daniel Robinson 《Magma (New York, N.Y.)》2016,29(3):435-449
Objective
To develop an analysis method that is sensitive to non-model-conform responses often encountered in ultra-high field presurgical planning fMRI. Using the consistency of time courses over a number of experiment repetitions, it should exclude low quality runs and generate activation maps that reflect the reliability of responses.Materials and methods
7 T fMRI data were acquired from six healthy volunteers: three performing purely motor tasks and three a visuomotor task. These were analysed with the proposed approach (UNBIASED) and the GLM.Results
UNBIASED results were generally less affected by false positive results than the GLM. Runs that were identified as being of low quality were confirmed to contain little or no activation. In two cases, regions were identified as activated in UNBIASED but not GLM results. Signal changes in these areas were time-locked to the task, but were delayed or transient.Conclusion
UNBIASED is shown to be a reliable means of identifying consistent task-related signal changes regardless of response timing. In presurgical planning, UNBIASED could be used to rapidly generate reliable maps of the consistency with which eloquent brain regions are activated without recourse to task timing and despite modified hemodynamics.140.
Fouto Ana R. Nunes Rita G. Pinto Joana Alves Luísa Calado Sofia Gonçalves Carina Rebolo Margarida Viana-Baptista Miguel Vilela Pedro Figueiredo Patrícia 《Magma (New York, N.Y.)》2022,35(5):779-790
Magnetic Resonance Materials in Physics, Biology and Medicine - Histogram-based metrics extracted from diffusion-tensor imaging (DTI) have been suggested as potential biomarkers for cerebral small... 相似文献