Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
12,993
result(s) for
"Yun, Yan"
Sort by:
كيف يحكم الحزب الشيوعي الصيني
مع التغيرات التاريخية وتقلبات الزمن، ظل العالم يتساءل : من أين جاءت مكانة الحزب الشيوعي الصيني في قلوب الصينيين والعالم ؟ وكيف حاز ثقة الصينيين وتأييدهم ؟ وكيف يتغلب على الصعاب ؟ وكيف يقود الصين في ثبات لبدء رحلة الاشتراكية التحديثية الجديدة، مواجهة التغير العميق لأوضاع العالم والدولة والحزب ؟ يجيب هذا الكتاب على هذه التساؤلات عبر جوانب مختلفة من وجهات النظر ويدقق النظر ويستقصي أمور الحزب الشيوعي الصيني، فيرصد أفعاله ويبحث أقواله ويحلل إنجازاته خلال هذا الوقت الذي اقترب فيه من تحقيق النهضة العظيمة للأمة الصينية أكثر من أي فترة على مر التاريخ وذلك بتمشيط الحقب والخبرات التي مر بها الحزب الشيوعي الصيني خلال توليه الحكم.
BOOK
The role of PD-1 signaling in health and immune-related diseases
Programmed cell death 1 receptor (PD-1) and its ligands constitute an inhibitory pathway to mediate the mechanism of immune tolerance and provide immune homeostasis. Significantly, the binding partners of PD-1 and its associated ligands are diverse, which facilitates immunosuppression in cooperation with other immune checkpoint proteins. Accumulating evidence has demonstrated the important immunosuppressive role of the PD-1 axis in the tumor microenvironment and in autoimmune diseases. In addition, PD-1 blockades have been approved to treat various cancers, including solid tumors and hematological malignancies. Here, we provide a comprehensive review of the PD-1 pathway, focusing on the structure and expression of PD-1, programmed cell death 1 ligand 1 (PD-L1), and programmed cell death 1 ligand 2 (PD-L2); the diverse biological functions of PD-1 signaling in health and immune-related diseases (including tumor immunity, autoimmunity, infectious immunity, transplantation immunity, allergy and immune privilege); and immune-related adverse events related to PD-1 and PD-L1 inhibitors.
Journal Article
Gut microbiota-derived propionate mediates the neuroprotective effect of osteocalcin in a mouse model of Parkinson’s disease
Background
Parkinson’s disease (PD) is a neurodegenerative disorder with no absolute cure. The evidence of the involvement of gut microbiota in PD pathogenesis suggests the need to identify certain molecule(s) derived from the gut microbiota, which has the potential to manage PD. Osteocalcin (OCN), an osteoblast-secreted protein, has been shown to modulate brain function. Thus, it is of interest to investigate whether OCN could exert protective effect on PD and, if yes, whether the underlying mechanism lies in the subsequent changes in gut microbiota.
Results
The intraperitoneal injection of OCN can effectively ameliorate the motor deficits and dopaminergic neuronal loss in a 6-hydroxydopamine-induced PD mouse model. The further antibiotics treatment and fecal microbiota transplantation experiments confirmed that the gut microbiota was required for OCN-induced protection in PD mice. OCN elevated
Bacteroidetes
and depleted
Firmicutes
phyla in the gut microbiota of PD mice with elevated potential of microbial propionate production and was confirmed by fecal propionate levels. Two months of orally administered propionate successfully rescued motor deficits and dopaminergic neuronal loss in PD mice. Furthermore, AR420626, the agonist of FFAR3, which is the receptor of propionate, mimicked the neuroprotective effects of propionate and the ablation of enteric neurons blocked the prevention of dopaminergic neuronal loss by propionate in PD mice.
Conclusions
Together, our results demonstrate that OCN ameliorates motor deficits and dopaminergic neuronal loss in PD mice, modulating gut microbiome and increasing propionate level might be an underlying mechanism responsible for the neuroprotective effects of OCN on PD, and the FFAR3, expressed in enteric nervous system, might be the main action site of propionate.
CoKvBsES-WQ_2hkhyhEj9X
Video abstract
Journal Article
Transforming biorefinery designs with ‘Plug-In Processes of Lignin’ to enable economic waste valorization
Biological lignin valorization has emerged as a major solution for sustainable and cost-effective biorefineries. However, current biorefineries yield lignin with inadequate fractionation for bioconversion, yet substantial changes of these biorefinery designs to focus on lignin could jeopardize carbohydrate efficiency and increase capital costs. We resolve the dilemma by designing ‘plug-in processes of lignin’ with the integration of leading pretreatment technologies. Substantial improvement of lignin bioconversion and synergistic enhancement of carbohydrate processing are achieved by solubilizing lignin via lowering molecular weight and increasing hydrophilic groups, addressing the dilemma of lignin- or carbohydrate-first scenarios. The plug-in processes of lignin could enable minimum polyhydroxyalkanoate selling price at as low as $6.18/kg. The results highlight the potential to achieve commercial production of polyhydroxyalkanoates as a co-product of cellulosic ethanol. Here, we show that the plug-in processes of lignin could transform biorefinery design toward sustainability by promoting carbon efficiency and optimizing the total capital cost.
The current biorefineries yield lignin with inadequate fractionation for bioconversion, yet substantial changes of these biorefinery designs could jeopardize carbohydrate efficiency and increase capital costs. Here the authors resolve the dilemma by designing ‘plug-in processes of lignin’ to enable economic waste valorization.
Journal Article
Prevention and control of COVID-19 by primary health care facilities in China: a field-survey-based qualitative study in three typical cities
Background
During the coronavirus disease 2019 (COVID-19) containment, primary health care (PHC) facilities inChina played an important role in providing both healthcare and public care services to community populations. The tasks of COVID-19 containment facilitated by PHC facilities were different among different regions and during different periods of COVID-19 pandemic. We sought to investigate the gaps on task participation, explore existing problems and provide corresponding solutions.
Methods
Semi-structured face-to-face interviews with COVID-19 prevention and control management teams of PHC facilities were conducted. Purposive stratified sampling was used and 32 team members of 22 PHC facilities were selected from Wuhan (as high-risk city), Shanghai (as medium-risk city) and Zunyi (as low-risk city). Framework analysis was employed to analyze the transcribed recordings.
Results
The main tasks of PHC facilities during the early period of the pandemic included assisting in contact tracing and epidemiological investigation, screening of populations at high-risk at travel centers/internals, house-by-house, or pre-examination/triage within PHC facilities; at-home/ centralized quarantine management; the work of fever sentinel clinics.
Further analyses revealed the existing problems and suggestions for improvement or resolutions. Regular medical supply reserves were recommended because of the medical supply shortage during the pre-outbreak period. Temporarily converted quarantine wards and centralized quarantine centers could be used to deal with pressures on patients’ treatment and management of the febrile patients. Only after strict evaluation of nucleic acid testing (NAT) results and housing conditions, decision on quarantine at-home or centralized quarantine centers could be made. Settings of fever sentinel clinics at PHC facilities allowed fever patients with no COVID-19 infection risks for treatment without being transferred to fever clinics of the designed secondary hospitals. Psychological intervention was sometimes in need and really helped in addressing individuals’ mental pressures.
Conclusions
During the COVID-19 containment, PHC facilities in China were responsible for different tasks and several problems were encountered in the working process. Accordingly, specific and feasible suggestions were put forward for different problems. Our findings are highly beneficial for healthcare teams and governments in handling similar situations.
Journal Article
Optimization of fermentation conditions through response surface methodology for enhanced antibacterial metabolite production by Streptomyces sp. 1-14 from cassava rhizosphere
Streptomyces species 1-14 isolated from cassava rhizosphere soil were evaluated for their antibacterial efficacy against Fusarium oxysporum f.sp. cubense race 4 (FOC4). Of the 63 strains tested, thirteen exhibited potent antibacterial properties and were further screened against eight fungal pathogens. The strain that showed maximum inhibition against all of the test pathogens was identified by 16S rDNA sequencing as Streptomyces sp. 1-14, was selected for further studies. Through the propagation of Streptomyces sp. 1-14 in soil under simulated conditions, we found that FOC4 did not significantly influence the multiplication and survival of Streptomyces sp. 1-14, while indigenous microorganisms in the soil did significantly influence Streptomyces sp. 1-14 populations. To achieve maximum metabolite production, the growth of Streptomyces 1-14 was optimized through response surface methodology employing Plackett-Burman design, path of steepest ascent determinations and Box-Behnken design. The final optimized fermentation conditions (g/L) included: glucose, 38.877; CaCl2•2H2O, 0.161; temperature, 29.97°C; and inoculation amount, 8.93%. This optimization resulted in an antibacterial activity of 56.13% against FOC4, which was 12.33% higher than that before optimization (43.80%). The results obtained using response surface methodology to optimize the fermentation medium had a significant effect on the production of bioactive metabolites by Streptomyces sp. 1-14. Moreover, during fermentation and storage, pH, light, storage temperature, etc., must be closely monitored to reduce the formation of fermentation products with reduced antibacterial activity. This method is useful for further investigations of the production of anti-FOC4 substances, and could be used to develop bio-control agents to suppress or control banana fusarium wilt.
Journal Article
Effects of Native Arbuscular Mycorrhizae Isolated on Root Biomass and Secondary Metabolites of Salvia miltiorrhiza Bge
Arbuscular mycorrhiza fungi (AMFs) are a group of soil-dwelling fungi that form symbiotic associations with plants, to mediate the secondary metabolism and production of active ingredients in aromatic and medicinal plants. Currently, there is little research on Salvia miltiorrhiza Bge. inoculation with native AMFs and the concomitant effects on growth and secondary metabolites. In this study, S. miltiorrhiza was treated with eight AMFs, i.e., Glomus formosanum ; Gl. tenebrosum ; Septoglomus constrictum ; Funneliformis geosporum ; Rhizophagus manihotis ; Ambispora gerdemanii ; Acaulospora laevis ; Ac. tuberculata , to investigate the influence of AMF inoculation on biomass and secondary production under greenhouse conditions in S. miltiorrhiza roots. The results showed that mycorrhiza formation rates were between 54.83 and 86.10%. Apart from Ac. laevis and Gl. tenebrosum treatment, the roots biomass of the other treatment groups was effectively increased, and the fresh and dry weight of the plant inoculated with Fu. geosporum were increased by 86.76 and 86.95%, respectively. Specifically, AMF treatments also impacted on phenolic acids production; inoculation with both Fu. geosporum or Ac. laevis significantly reduced total phenolic acids, whereas the other treatments effectively increased these levels, of which Gl. formosanum generated significant levels. Most AMF-plant symbiotic experiments facilitated phenolic acid accumulation in the secondary metabolites of S. miltiorrhiza (except Ac. laevis ). This study showed that most native AMFs inoculation with S. miltiorrhiza promoted roots growth and increased secondary metabolites production (especially phenolic acids). Going forward, inoculation of native AMF is a promising method to improve the quality and yield of S. miltiorrhiza and should be considered during production.
Journal Article
Intrinsic topological metal state in T-graphene
An intrinsic topological metal (TM) state is found in the T-graphene, a monolayer with both the time-reversal symmetry and the four-fold symmetry. The state distinguishes itself by the nontrivial electric polarization from the ordinary metals and features with two local edge states in the corresponding nanoribbons. The TM state is confirmed as a transition state bridging the ordinary metal state and the topological insulator state when the relative neighboring hoppings change in the lattice. The topological nature is further verified by checking the robustness of transport property against randomly-introduced strong disorders. The fact that the multiple topological states indexed by different parameters coexist in such a practical system shows a broad prospect in versatile topological transport devices.
Journal Article
Piecewise ensemble averaging stochastic Liouville equations for simulating non-Markovian quantum dynamics
Here we present a novel stochastic Liouville equation with piecewisely correlated noises, in which the inter-piece correlation is rigorously incorporated by a convolution integral involving functional derivatives. Due to the feature of piecewise correlation, we can perform piecewise ensemble average and serve the average of the preceding interval as the initial condition of the subsequent propagation. This strategy avoids the long-time stochastic average and the statistical errors are saturated at long times. By doing so, we circumvent the intrinsic difficulty of the stochastic simulations caused by the fast increase in the variance of the quantum Brownian motion. Therefore, as demonstrated by the numerical examples, the proposed method enables us to simulate the long-time quantum dissipative dynamics with long memories in the non-perturbative regime.
Journal Article
Recent Advances in the Application of Functionalized Lignin in Value-Added Polymeric Materials
The quest for converting lignin into high-value products has been continuously pursued in the past few decades. In its native form, lignin is a group of heterogeneous polymers comprised of phenylpropanoids. The major commercial lignin streams, including Kraft lignin, lignosulfonates, soda lignin and organosolv lignin, are produced from industrial processes including the paper and pulping industry and emerging lignocellulosic biorefineries. Although lignin has been viewed as a low-cost and renewable feedstock to replace petroleum-based materials, its utilization in polymeric materials has been suppressed due to the low reactivity and inherent physicochemical properties of lignin. Hence, various lignin modification strategies have been developed to overcome these problems. Herein, we review recent progress made in the utilization of functionalized lignins in commodity polymers including thermoset resins, blends/composites, grafted functionalized copolymers and carbon fiber precursors. In the synthesis of thermoset resins such as polyurethane, phenol-formaldehyde and epoxy, they are covalently incorporated into the polymer matrix, and the discussion is focused on chemical modifications improving the reactivity of technical lignins. In blends/composites, functionalization of technical lignins is based upon tuning the intermolecular forces between polymer components. In addition, grafted functional polymers have expanded the utilization of lignin-based copolymers to biomedical materials and value-added additives. Different modification approaches have also been applied to facilitate the application of lignin as carbon fiber precursors, heavy metal adsorbents and nanoparticles. These emerging fields will create new opportunities in cost-effectively integrating the lignin valorization into lignocellulosic biorefineries.
Journal Article