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41.
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目前,以计算机信.g-系统为犯罪对象和工具的新型犯罪活动越来越多,造成的危害也越来越大。侦破这些案件必须要用到计算机取证技术,而电子证据本身和取证过程有许多不同于传统物证和取证的特点,给司法工作和信息安全领域都提出了新的挑战。为此,文章设计开发了一款基于WindowsPE系统的便捷、实用、安全、有效的计算机便携式取证系统。电子证据的收集与处理是通过内置于u盘的WindowsPE系统来完成的;利用OpenSSL提供的编程接口和PKI相关技术实现对电子证据的保密、认证与保存等功能。最后通过测试与分析,表明该系统能实现对电子证据的收集、处理和电子证据的安全有效保存。 相似文献
43.
Lisa Goedtke Heike Sprenger Ute Hofmann Felix F. Schmidt Helen S. Hammer Ulrich M. Zanger Oliver Poetz Albrecht Seidel Albert Braeuning Stefanie Hessel-Pras 《International journal of molecular sciences》2021,22(1)
Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants produced by incomplete combustion of organic matter. They induce their own metabolism by upregulating xenobiotic-metabolizing enzymes such as cytochrome P450 monooxygenase 1A1 (CYP1A1) by activating the aryl hydrocarbon receptor (AHR). However, previous studies showed that individual PAHs may also interact with the constitutive androstane receptor (CAR). Here, we studied ten PAHs, different in carcinogenicity classification, for their potential to activate AHR- and CAR-dependent luciferase reporter genes in human liver cells. The majority of investigated PAHs activated AHR, while non-carcinogenic PAHs tended to activate CAR. We further characterized gene expression, protein abundancies and activities of the AHR targets CYP1A1 and 1A2, and the CAR target CYP2B6 in human HepaRG hepatoma cells. Enzyme induction patterns strongly resembled the profiles obtained at the receptor level, with AHR-activating PAHs inducing CYP1A1/1A2 and CAR-activating PAHs inducing CYP2B6. In summary, this study provides evidence that beside well-known activation of AHR, some PAHs also activate CAR, followed by subsequent expression of respective target genes. Furthermore, we found that an increased PAH ring number is associated with AHR activation as well as the induction of DNA double-strand breaks, whereas smaller PAHs activated CAR but showed no DNA-damaging potential. 相似文献
44.
Lejla Medzikovic Hylja Heese Pieter B. van Loenen Cindy P. A. A. van Roomen Ingeborg B. Hooijkaas Vincent M. Christoffels Esther E. Creemers Carlie J. M. de Vries Vivian de Waard 《International journal of molecular sciences》2021,22(4)
Fibrosis is a hallmark of adverse cardiac remodeling, which promotes heart failure, but it is also an essential repair mechanism to prevent cardiac rupture, signifying the importance of appropriate regulation of this process. In the remodeling heart, cardiac fibroblasts (CFs) differentiate into myofibroblasts (MyoFB), which are the key mediators of the fibrotic response. Additionally, cardiomyocytes are involved by providing pro-fibrotic cues. Nuclear receptor Nur77 is known to reduce cardiac hypertrophy and associated fibrosis; however, the exact function of Nur77 in the fibrotic response is yet unknown. Here, we show that Nur77-deficient mice exhibit severe myocardial wall thinning, rupture and reduced collagen fiber density after myocardial infarction and chronic isoproterenol (ISO) infusion. Upon Nur77 knockdown in cultured rat CFs, expression of MyoFB markers and extracellular matrix proteins is reduced after stimulation with ISO or transforming growth factor–β (TGF-β). Accordingly, Nur77-depleted CFs produce less collagen and exhibit diminished proliferation and wound closure capacity. Interestingly, Nur77 knockdown in neonatal rat cardiomyocytes results in increased paracrine induction of MyoFB differentiation, which was blocked by TGF-β receptor antagonism. Taken together, Nur77-mediated regulation involves CF-intrinsic promotion of CF-to-MyoFB transition and inhibition of cardiomyocyte-driven paracrine TGF-β-mediated MyoFB differentiation. As such, Nur77 provides distinct, cell-specific regulation of cardiac fibrosis. 相似文献
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DNA methylation is a prevalent regulatory modification in prokaryotes and eukaryotes. N1-methyladenine (m1A) and N6-methyladenine (m6A) have been found to be capable of altering DNA structures via disturbing Watson–Crick base pairing. However, little has been known about their influences on non-B DNA structures, which are associated with genetic instabilities. In this work, we investigated the effects of m1A and m6A on both the structure and thermodynamic stability of a newly reported DNA minidumbbell formed by two TTTA tetranucleotide repeats. As revealed by the results of nuclear magnetic resonance spectroscopic studies, both m1A and m6A favored the formation of a T·m1A and T·m6A Hoogsteen base pair, respectively. More intriguingly, the m1A and m6A modifications brought about stabilization and destabilization effects on the DNA minidumbbell, respectively. This work provides new biophysical insights into the effects of adenine methylation on the structure and thermodynamic stability of DNA. 相似文献
47.
综述了环境因素,包括温度、PH值、溶解氧、氯离子、氢、荷性碱含硫化合物以及铅等对压水堆核电站蒸汽发生器传热管用基合金材料(800、600、690合金)和腐蚀破裂(SCC)敏感性的影响。 相似文献
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50.
1H dipolar decoupled 13C n.m.r. experiments with the aid of the magic angle spinning technique have been used to determine the graft content and the isomer content of the polybutadiene grafts in a graft copolymer with isotactic polypropylene. 相似文献