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排序方式: 共有388条查询结果,搜索用时 16 毫秒
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A review of the literature on the impact of sexual contacts between adults and boys reveals the existence of two principal outcomes: 1) some participants develop various disorders once in adulthood, such as behavioural problems, sexual disorders, or personality problems; 2) some participants do not present with any major disorders in the long run. These different outcomes may be associated with several moderating variables related to the sexual contacts, such as the level of coercion at the time of these contacts, the bond between the child and the adult, or the context of the sexual relation. However, the conclusions relating to the relations between early sexual contacts with adults and subsequent problems of adaptation in adulthood are difficult to determine. This is because of various methodological problems associated with relevant studies (i.e., definition of these contacts, nature of the sample, method evaluation, statistical analyses). In this article, we propose certain avenues of research that may help clarify this problem. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Jan Haas Karen S. Frese Farbod Sedaghat-Hamedani Elham Kayvanpour Rewati Tappu Rouven Nietsch Oguz Firat Tugrul Michael Wisdom Carsten Dietrich Ali Amr Tanja Weis Torsten Niederdrnk Michael P. Murphy Thomas Krieg Marcus Drr Uwe Vlker Jens Fielitz Norbert Frey Stephan B. Felix Andreas Keller Hugo A. Katus Benjamin Meder 《International journal of molecular sciences》2021,22(4)
With more than 25 million people affected, heart failure (HF) is a global threat. As energy production pathways are known to play a pivotal role in HF, we sought here to identify key metabolic changes in ischemic- and non-ischemic HF by using a multi-OMICS approach. Serum metabolites and mRNAseq and epigenetic DNA methylation profiles were analyzed from blood and left ventricular heart biopsy specimens of the same individuals. In total we collected serum from n = 82 patients with Dilated Cardiomyopathy (DCM) and n = 51 controls in the screening stage. We identified several metabolites involved in glycolysis and citric acid cycle to be elevated up to 5.7-fold in DCM (p = 1.7 × 10−6). Interestingly, cardiac mRNA and epigenetic changes of genes encoding rate-limiting enzymes of these pathways could also be found and validated in our second stage of metabolite assessment in n = 52 DCM, n = 39 ischemic HF and n = 57 controls. In conclusion, we identified a new set of metabolomic biomarkers for HF. We were able to identify underlying biological cascades that potentially represent suitable intervention targets. 相似文献
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Mechanical properties of wood plastic composites (WPCs) manufactured from sawdust and virgin and/or recycled plastics, namely high density polyethylene (HDPE) and polypropylene (PP), were studied. Sawdust was prepared from beech industrial sawdust by screening to the desired particle size and was mixed with different virgin or recycled plastics at 50% by weight fiber loading. The mixed materials were then compression molded into panels. Flexural and tensile properties and impact strength of the manufactured WPCs were determined according to the relevant standard specifications. Although composites containing PP (virgin and recycled) exhibited higher stiffness and strength than those made from HDPE (virgin and recycled), they had lower unnotched impact strengths. Mechanical properties of specimens containing recycled plastics (HDPE and PP) were statistically similar and comparable to those of composites made from virgin plastics. This was considered as a possibility to expand the use of recycled plastics in the manufacture of WPCs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3641–3645, 2006 相似文献
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Time delays are encountered in many physical systems, and they usually threaten the stability and performance of closed-loop systems. The problem of determining all stabilising proportional-integral-derivative (PID) controllers for systems with perturbed delays is less investigated in the literature. In this study, the Rekasius substitution is employed to transform the system parameters to a new space. Then, the singular frequency (SF) method is revised for the Rekasius transformed system. A novel technique is presented to compute the ranges of time delay for which stable PID controller exists. This stability range cannot be readily computed from the previous methods. Finally, it is shown that similar to the original SF method, finite numbers of singular frequencies are sufficient to compute the stable regions in the space of time delay and controller coefficients. 相似文献
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A new nano-thermo-mechanical data storage memory is presented which combines two technologies of thermal actuation and buckling beam memory. The memory design is resistant in high radiation environments, making it a reliable memory for spacecraft computer systems. This memory has a data storage density, write/erase speed, and power consumption comparable with current memories. An integrated thermal–mechanical simulation of buckling in nano-mechanical memory is performed to optimize the design parameters. The preliminary system is a bridge with lengths of 20–40 μm, a width of 1 μm, and a thickness of 0.3 μm, in air with a pressure of 5 kPa. The simulation of high energy particle collisions shows radiation does not cause undesired buckling for silicon and silicon carbide bits, which makes the memory applicable for Jovian exploration. Optimization simulations are performed for silicon, silicon carbide, and kapton with various dimensions and actuation heating rates. The current work suggests the length of 20 μm for the bridge to balance the write time and the storage density. Among the beams with the fixed dimensions, kapton shows the fastest write time, with the lowest energy cost. However, high energy electron collision causes buckling in kapton, limiting its use in high radiation applications. The results show that silicon and silicon carbide based systems are viable for use in the extreme radiation environments that will be encountered in future space exploration missions. 相似文献
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Elham Khanipour Steve H. Flint Owen J. McCarthy Matt Golding Jon Palmer Mark Tamplin 《International Journal of Food Science & Technology》2014,49(6):1506-1512
The aim of this study was to evaluate the combined effect of salt (sodium chloride, 0–8% w/v), sorbate (potassium sorbate, 0–4.5% w/v), nisin (0–500 ppm) and lysozyme (0–500 ppm) on the survival of Clostridium sporogenes as a non‐toxigenic surrogate of Clostridium botulinum in terms of the probability of growth by using a central composite rotatable design. The results indicated that salt and sorbate were the most effective factors in preventing the growth of Cl. sporogenes in high‐moisture (>95%) and low‐acid conditions. The probability of growth of Cl. sporogenes in broth was reduced by combinations of salt and sorbate. Nisin and lysozyme had insignificant effects on the probability of growth of Cl. sporogenes (P > 0.05). Lysozyme individually and in combination with nisin had no inhibitory effect on Cl. sporogenes. Overall, the addition of sorbate and lysozyme may allow the salt concentration to be reduced while preventing growth. 相似文献
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Rapid growth of digital data and their security concerns increases the significance of enhancing advanced encryption techniques. Encryption is the backbone of secure communication in networks and the physical process of scrambling and permuting data in order to make them impossible to understand for unauthorized users. This paper proposes a novel audio signal encryption method, based on a mixture of three chaos functions. Due to the reversibility of the chaos functions, the decryption process is the inverse of the encryption process. This method was applied to audio signals with various sizes and the encoded messages were compared to the original ones. Simulation results and theoretical analyses show that the proposed approach offers a significant gain in terms of robustness and computational complexity. 相似文献