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381.
The skin is our primary shield against microbial pathogens and has evolved innate and adaptive strategies to enhance immunity
in response to injury or microbial insult. The study of antimicrobial peptide (AMP) production in mammalian skin has revealed
several of the elegant strategies that AMPs use to prevent infection. AMPs are inducible by both infection and injury and
protect the host by directly killing pathogens and/or acting as multifunctional effector molecules that trigger cellular responses
to aid in the anti-infective and repair response. Depending on the specific AMP, these molecules can influence cytokine production,
cell migration, cell proliferation, differentiation, angiogenesis and wound healing. Abnormal production of AMPs has been
associated with the pathogenesis of several cutaneous diseases and plays a role in determining a patient’s susceptibility
to pathogens. This review will discuss current research on the regulation and function of AMPs in the skin and in skin disorders. 相似文献
382.
Host defense peptides and proteins are important components of the innate host defense against pathogenic microorganisms.
They target negatively charged bacterial surfaces and disrupt microbial cytoplasmic membranes, which ultimately leads to bacterial
destruction. Throughout evolution, pathogens devised several mechanisms to protect themselves from deleterious damage of host
defense peptides. These strategies include (a) inactivation and cleavage of host defense peptides by production of host defense
binding proteins and proteases, (b) repulsion of the peptides by alteration of pathogen’s surface charge employing modifications
by amino acids or amino sugars of anionic molecules (e.g., teichoic acids, lipid A and phospholipids), (c) alteration of bacterial
membrane fluidity, and (d) expulsion of the peptides using multi drug pumps. Together with bacterial regulatory network(s)
that regulate expression and activity of these mechanisms, they represent attractive targets for development of novel antibacterials. 相似文献
383.
This review describes the properties of some rare eukaryotic chaperones that each assist in the folding of only one target
protein. In particular, we describe (1) the tubulin cofactors, (2) p47, which assists in the folding of collagen, (3) α-hemoglobin
stabilizing protein (AHSP), (4) the adenovirus L4-100 K protein, which is a chaperone of the major structural viral protein,
hexon, and (5) HYPK, the huntingtin-interacting protein. These various-sized proteins (102–1,190 amino acids long) are all
involved in the folding of oligomeric polypeptides but are otherwise functionally unique, as they each assist only one particular
client. This raises a question regarding the biosynthetic cost of the high-level production of such chaperones. As the clients
of faithful chaperones are all abundant proteins that are essential cellular or viral components, it is conceivable that this
necessary metabolic expenditure withstood evolutionary pressure to minimize biosynthetic costs. Nevertheless, the complexity
of the folding pathways in which these chaperones are involved results in error-prone processes. Several human disorders associated
with these chaperones are discussed. 相似文献
384.
Chen ZW 《Cellular and molecular life sciences : CMLS》2011,68(14):2409-2417
Accumulating evidence suggests that human γδ T cells act as non-classical T cells and contribute to both innate and adaptive
immune responses in infections. Vγ2 Vδ2 T (also termed Vγ9 Vδ2 T) cells exist only in primates, and in humans represent a
dominant circulating γδ T-cell subset. Primate Vγ2 Vδ2 T cells are the only γδ T cell subset capable of recognizing microbial
phosphoantigen. Since nonhuman primate Vγ2 Vδ2 T cells resemble their human counterparts, in-depth studies have been undertaken
in macaques to understand the biology and function of human Vγ2 Vδ2 T cells. This article reviews the recent progress for
immune biology of Vγ2 Vδ2 T cells in infections. 相似文献
385.
Through molecular dynamics(MD)simulation,the dependencies of temperature,grain size and strain rate on the mechanical properties were studied.The simulation results demonstrated that the strain rate from 0.05 to 2 ns~(–1 )affected the Young’s modulus of nickel nanowires slightly,whereas the yield stress increased.The Young’s modulus decreased approximately linearly;however,the yield stress firstly increased and subsequently dropped as the temperature increased.The Young’s modulus and yield stress increased as the mean grain size increased from 2.66 to6.72 nm.Moreover,certain efforts have been made in the microstructure evolution with mechanical properties association under uniaxial tension.Certain phenomena such as the formation of twin structures,which were found in nanowires with larger grain size at higher strain rate and lower temperature,as well as the movement of grain boundaries and dislocation,were detected and discussed in detail.The results demonstrated that the plastic deformation was mainly accommodated by the motion of grain boundaries for smaller grain size.However,for larger grain size,the formations of stacking faults and twins were the main mechanisms of plastic deformation in the polycrystalline nickel nanowire. 相似文献
386.
In this paper, a life-cycle model with retirement is set up to study how an individual chooses the optimal retiring age on account of wage growth rate, longevity and healthy state. It is proved that there exists optimal retiring age under given conditions. The numerical simulations are given to show how wage growth rate, longevity and healthy state affect retiring age. 相似文献
387.
Quantitative analysis has always been a difficult problem in security analysis of intrusion tolerance systems. An intrusion tolerance model based on multiple recovery mechanisms is introduced in this paper and how to quantify the security attributes of the model is proposed. A state transition model with recovery states more accurately describes the dynamic behavior of the system. Considering that recovery mechanisms have a great impact on the security performance of the system, we set up the cost models corresponding to different recovery mechanisms. We propose a feasible security measure based on mean cost to security failure in order to evaluate the system cost during the recovery phase. The experimental results confirmed the feasibility of the proposed methods. 相似文献
388.
This paper described an improved underwater confrontation simulation method of naval amphibious operational training system. The initial position of submarine forces on the enemy is generated automatically, and the attacking distance model of torpedoes is established based on the kinematics theory, which is more flexible and reasonable to judge the launch condition compared to traditional method. The two kinds of confrontation behavior models on the enemy submarine are created to depict its tactical action from the defensive to the offensive as well as the contrary, ensuring that operational style is simulated more comprehensively and properly. The existing motion trajectory estimation and collision detection algorithms on operational platforms are also improved to reduce the iteration error and further enhance the detection accuracy of target hit. 相似文献
389.
End-use energy consumption can reflect the industrial development of a country and the living standards of its residents. The study of end-use energy consumption can provide a solid basis for industrial restructuring, energy saving, and emission reduction. In this paper, we analyzed the end-use energy consumption of a region in Northwestern China, and applied the Markov prediction method to forecast the future demand of different types of end-use energy. This provides a reference for the energy structure optimization in the Northwestern China. 相似文献
390.
Cloud storage service reduces the burden of data users by storing users’ data files in the cloud. But, the files might be modified in the cloud. So, data users hope to check data files integrity periodically. In a public auditing protocol, there is a trusted auditor who has certain ability to help users to check the integrity of data files. With the advantages of no public key management and verification, researchers focus on public auditing protocol in ID-based cryptography recently. However, some existing protocols are vulnerable to forgery attack. In this paper, based on ID-based signature technology, by strengthening information authentication and the computing power of the auditor, we propose an ID-based public auditing protocol for cloud data integrity checking. We also prove that the proposed protocol is secure in the random oracle model under the assumption that the Diffie-Hellman problem is hard. Furthermore, we compare the proposed protocol with other two ID-based auditing protocols in security features, communication efficiency and computation cost. The comparisons show that the proposed protocol satisfies more security features with lower computation cost. 相似文献