Prominent formal theories of conflict provide considerable insight into how civil wars begin and end, but offer little understanding of how they proceed during wartime. One prevalent pattern is that ...rebel strategies vary significantly within conflicts over time, from guerrilla to conventional tactics. Why do rebels switch between different fighting strategies? How does the transition affect civil war negotiations? I develop a model of rebel–government negotiation in which rebels choose fighting strategies throughout a multiperiod war. The analysis shows that rebels switch from guerrilla to conventional tactics after gaining strength, and the expectation of growth delays rebels' transition to conventional fighting. The potential switch between different fighting strategies hurts the prospects for peace and prolongs civil wars. I identify the generic conditions under which peace is infeasible, no matter how belligerents negotiate. These conditions characterize the incipient stages of many rebellions, thereby explaining the lack of serious negotiations early on.
Summary
Immunoglobulins emerging from B lymphocytes and capable of recognizing almost all kinds of antigens owing to the extreme diversity of their antigen‐binding portions, known as variable (V) ...regions, play an important role in immune responses. The exons encoding the V regions are known as V (variable), D (diversity), or J (joining) genes. V, D, J segments exist as multiple copy arrays on the chromosome. The recombination of the V(D)J gene is the key mechanism to produce antibody diversity. The recombinational process, including randomly choosing a pair of V, D, J segments, introducing double‐strand breaks adjacent to each segment, deleting (or inverting in some cases) the intervening DNA and ligating the segments together, is defined as V(D)J recombination, which contributes to surprising immunoglobulin diversity in vertebrate immune systems. To enhance both the ability of immunoglobulins to recognize and bind to foreign antigens and the effector capacities of the expressed antibodies, naive B cells will undergo class switching recombination (CSR) and somatic hypermutation (SHM). However, the genetics mechanisms of V(D)J recombination, CSR and SHM are not clear. In this review, we summarize the major progress in mechanism studies of immunoglobulin V(D)J gene recombination and CSR as well as SHM, and their regulatory mechanisms.
Developments of novel experimental methodologies and analysis techniques have elucidated more molecules and mechanisms concerning the generation and regulation of immunoglobulin. This review summarizes the current state of research concerning the mechanism of immunoglobulin V(D)J recombination, CSR as well as SHM, and their regulatory mechanisms.
To discover the distribution and risk of pesticides in Jiulong River and estuary, the residues of 102 pesticides were analyzed in water, sediment and clam samples collected from 35 sites in different ...seasons. A total number of 82 pesticides were detected and the occurrence and the risk to human and fish were assessed. Most of pesticides with high frequency were medium or low toxic except for DDTs. DDTs were the significant contaminant and the widely used dicofol was the new source of DDTs. The spatial and seasonal variation of pesticide distribution was linked with the distribution of orchards and farmlands. Health risk from river water consumption was low (RQ < 0.1) while that from clam consumption was medium (RQ = 0.84). Pesticides in water posed great risk to fish and among the 76 water samples analyzed, 65 of them showed high risk (RQ > 1) and 6 showed medium risk (0.1 ≤ QR < 1). The single chemical posed high risk to fish included DDTs, triazophos, fenvalerate, bifenthrin and cyfluthrin, and those showed medium risk included dicofol, butachlor, isocarbophos, terbufos and cyhalothrin. There were 14 single pesticides detected with concentration above 100 ng L−1 in this study and the pesticide with the highest concentration was procymidone (3904 ng L−1). Further experiments illustrated that procymidone could disrupt the expression of vitellogenin in the estuarine fish even at environmental concentrations. DDTs, dicofol, triazophos, isocarbophos, terbufos, cyfluthrin, bifenthrin, fenvalerate, cyhalothrin, butachlor and procymidone have become the significant pesticides and should be considered in aquatic ecosystem risk management.
•Distribution of 82 pesticides in Jiulong River and estuary were analyzed and the risks were assessed.•Moderately or low toxic pesticides made up the main portion of residues except DDTs.•DDTs in clam posed main health risks to consumers and pesticides in water posed high risk to fish.•At least 24 detected pesticides were EDCs and EDC effects of procymidone on local fish were observed.•The pesticides with high eco-risk included DDTs, triazophos, fenvalerate, bifenthrin and cyfluthrin.
Esophageal cancer (EC) is one of common malignant neoplasms in the world. Due to dietary habits, environmental factors, stress and so on, larger numbers of person are diagnose with EC every year. ...Currently, the clinical treatment of EC mainly includes radiotherapy, chemotherapy, surgical resection alone or combined strategy. These treatment options are insufficient and often associated with a number of side effects. Medicinal herbs containing Traditional Chinese Medicine (TCM) have been used as an adjunct treatment for alleviating the side effects of chemotherapy or radiotherapy and for improving the quality of life of cancer patients. The monomer compounds obtained from medicinal herbs also exhibit potential anti-cancer activity against various type cancer cell lines including esophageal cancer, and have the ability to enhance cancer cells sensitizing to chemotherapy or radiotherapy. In this review, we summarize some monomers and composite of medicinal herbs with anti-cancer activity for EC, and elaborate their mechanism of action. Understanding the exact mechanism of their actions may provide valuable information for their possible application in cancer therapy and prevention. This is beneficial for the use and development of medicinal herbs for diseases therapy in the future.
Accumulating evidence suggests that histone hypoacetylation which is partly mediated by histone deacetylase (HDAC), plays a causative role in the etiology of various clinical disorders such as cancer ...and central nervous diseases. HDAC inhibitors (HDACis) are natural or synthetic small molecules that can inhibit the activities of HDACs and restore or increase the level of histone acetylation, thus may represent the potential approach to treating a number of clinical disorders. This manuscript reviewed the progress of the most recent experimental application of HDACis as novel potential drugs or agents in a large number of clinical disorders including various brain disorders including neurodegenerative and neurodevelopmental cognitive disorders and psychiatric diseases like depression, anxiety, fear and schizophrenia, and cancer, endometriosis and cell reprogramming in somatic cell nuclear transfer in human and animal models of disease, and concluded that HDACis as potential novel therapeutic agents could be used alone or in adjunct to other pharmacological agents in various clinical diseases.
•Hypoacetylation which is partly mediated by histone deacetylase (HDAC), plays a causative role in the etiology of various clinical disorders.•HDAC inhibitors (HDACis) can restore or increase the level of histone acetylation.•HDACis as potential novel therapeutic agents could be used alone or in adjunct to other pharmacological agents in various clinical diseases.
Learners' behavioral intention to reuse e-learning is of great significance to the implementation and management of e-learning in higher education. This study examined the relationship between ...self-regulation and behavioral intention to reuse by focusing on the mediating role of study engagement and the moderating role of peer collaboration. Based on a sample of 379 undergraduates from central China, we found that self-regulation positively influences behavioral intention to reuse
study engagement. In addition, moderated path analysis indicated that peer collaboration strengthened the direct effect of self-regulation on study engagement and its indirect effect on behavioral intention to reuse. Theoretical and practical implications of these findings are discussed as well.
Porous materials with ultrahigh specific strength are highly desirable for aerospace, automotive and construction applications. However, because of the harsh processing of metal foams and intrinsic ...low strength of polymer foams, both are difficult to meet the demand for scalable development of structural foams. Herein, we present a supramolecular metallic foam (SMF) enabled by core-shell nanostructured liquid metals connected with high-density metal-ligand coordination and hydrogen bonding interactions, which maintain fluid to avoid stress concentration during foam processing at subzero temperatures. The resulted SMFs exhibit ultrahigh specific strength of 489.68 kN m kg
(about 5 times and 56 times higher than aluminum foams and polyurethane foams) and specific modulus of 281.23 kN m kg
to withstand the repeated loading of a car, overturning the previous understanding of the difficulty to achieve ultrahigh mechanical properties in traditional polymeric or organic foams. More importantly, end-of-life SMFs can be reprocessed into value-added products (e.g., fibers and films) by facile water reprocessing due to the high-density interfacial supramolecular bonding. We envisage this work will not only pave the way for porous structural materials design but also show the sustainable solution to plastic environmental risks.
Traditionally, immunoglobulin (Ig) was believed to be produced by only B-lineage cells. However, increasing evidence has revealed a high level of Ig expression in cancer cells, and this Ig is named ...cancer-derived Ig. Further studies have shown that cancer-derived Ig shares identical basic structures with B cell-derived Ig but exhibits several distinct characteristics, including restricted variable region sequences and aberrant glycosylation. In contrast to B cell-derived Ig, which functions as an antibody in the humoral immune response, cancer-derived Ig exerts profound protumorigenic effects
multiple mechanisms, including promoting the malignant behaviors of cancer cells, mediating tumor immune escape, inducing inflammation, and activating the aggregation of platelets. Importantly, cancer-derived Ig shows promising potential for application as a diagnostic and therapeutic target in cancer patients. In this review, we summarize progress in the research area of cancer-derived Ig and discuss the perspectives of applying this novel target for the management of cancer patients.
Magnetic iron oxide nanoparticles (MIONPs) are particularly attractive in biosensor, antibacterial activity, targeted drug delivery, cell separation, magnetic resonance imaging tumor magnetic ...hyperthermia, and so on because of their particular properties including superparamagnetic behavior, low toxicity, biocompatibility, etc. Although many methods had been developed to produce MIONPs, some challenges such as severe agglomeration, serious oxidation, and irregular size are still faced in the synthesis of MIONPs. Thus, various strategies had been developed for the surface modification of MIONPs to improve the characteristics of them and obtain multifunctional MIONPs, which will widen the applicational scopes of them. Therefore, the processes, mechanisms, advances, advantages, and disadvantages of six main approaches for the synthesis of MIONPs; surface modification of MIONPs with inorganic materials, organic molecules, and polymer molecules; applications of MIONPs or modified MIONPs; the technical challenges of synthesizing MIONPs; and their limitations in biomedical applications were described in this review to provide the theoretical and technological guidance for their future applications.
Although several studies on the effects of cadmium (Cd) on wheat have been reported, the gene expression profiles of different wheat tissues in response to gradient concentrations of Cd, and whether ...soil microorganisms are involved in the damage to wheat remain to be discovered. To gain further insight into the molecular mechanisms of Cd-resistance in wheat, we sowed bread wheat (Triticum aestivum) in artificially Cd-contaminated soil and investigated the transcriptomic response of the wheat roots, stems, and leaves to gradient concentrations of Cd, as well as the alteration of the soil microbiome. Results indicated that the root bioaccumulation factors increased with Cd when concentrations were < 10 mg/kg, but at even higher concentrations, the bioaccumulation factors decreased, which is consistent with the overexpression of metal transporters and other genes related to Cd tolerance. In the Cd-contaminated soil, the abundance of fungal pathogens increased, and the antimicrobial response in wheat root was observed. Most of the differentially expressed genes (DEGs) of wheat changed significantly when the Cd concentration increased above 10 mg/kg, and the transcriptional response is much greater in roots than in stems and leaves. The DEGs are mainly involved in Cd transport and chelation, antioxidative stress, antimicrobial responses, and growth regulation. COPT3 and ZnT1 were identified for the first time as the major transporters responding to Cd in wheat. Overexpression of the nicotianamine synthase and pectinesterase genes suggested that nicotianamine and pectin are the key chelators in Cd detoxification. endochitinase, chitinase, and snakin2 were involved in the anti-fungal stress caused by Cd-induced cell damage. Several phytohormone-related DEGs are involved in the root’s growth and repair. Overall, this study presents the novel Cd tolerance mechanisms in wheat and the changes in soil fungal pathogens that increase plant damage.
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•Transcriptomics and metagenomics unveil new Cd tolerance mechanisms in wheat.•Cd induced stress in wheat and increased pathogenic fungi in soil.•COPT3 and ZnT1 are key Cd-responsive transporter genes in wheat.•DEGs suggest nicotianamine and pectate as key Cd chelators in wheat.•Roots show higher bioaccumulation and stronger Cd response than stems and leaves.
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