1,342 research outputs found

    Landau level crossing in a spin-orbit coupled two-dimensional electron gas

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    We have studied experimentally theᅠLandau levelᅠ(LL) spectrum of a two-dimensionalᅠelectron gasᅠ(2DEG)ᅠin an In0.53Ga0.47As/InPᅠquantum wellᅠstructure by means of low-temperature magneto-transport coincidence measurement in vectorᅠmagnetic fields.ᅠIt is well known that LL crossing occurs in tiltedᅠmagnetic fieldsᅠdue to a competition between cyclotron energy andᅠZeeman effect.ᅠRemarkably, here we observe an additional type of level-crossing resulting from a competition between Rashba andᅠZeeman splittingᅠin a smallᅠmagnetic field,ᅠconsistent with theᅠtheoreticalᅠprediction for strongly spin-orbit coupledᅠ2DEG

    Learning network storage curriculum with experimental case based on embedded systems

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    In this paper, we present an experimental case for the course of Network Storage and Security, which benefited from an improved learning outcome for our students. The newly designed experiments-based contents are merged into the current course to help students obtain practical experiences about network storage. The experiments aim to build a network storage system based on available resources instead of any specialized network storage equipment. Technically, students can learn general practical knowledge of network storage on iSCSI (a network storage protocol based on IP technology) and also the technologies of embedded system. Through the experimental case, we found that it could fully enhance students\u27 comprehensive and practical abilities, develop students\u27 teamwork spirit and creativity, and especially improve the learning outcome of network storage curriculum. These learning and thinking methods can also be generalized and applied to other computer science related courses

    Vaccine Adjuvant Delivery Systems Constructed Using Biocompatible Nanoparticles Formed through Self-Assembly of Small Molecules

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    Subunit vaccines are playing a critical role in controlling numerous diseases and attracting more and more research interests due to their numerous advantages over conventional whole microbe-based vaccines. However, subunit vaccines are weak immunogens and thus have limited capacity in eliciting the humoral and cellular immunity against pathogens. Recently, nanoparticles (NPs) formed with certain small molecules through self-assembly have been employed as an effective carrier for subunit vaccines to play roles of adjuvant, delivery and stabilization of antigens, thus engendering a vaccine adjuvant-delivery system (VADS), which shows promises to overcome the hurdles in developing subunit vaccines. In particular, the small molecule-self-assembled NPs as a VADS can not only deliver vaccine ingredients to immune cells but also influence the immunoresponse toward a Th1 (type 1 T helper cell) and Th2 balanced pathway to establish both humoral and cellular immunity. This chapter describes the innovative VADSs based on the small molecule-self-assembled NPs, such as metal NPs (mNPs), emulsions, liposomes, and ISCOMs, which are elaborately designed for the development of subunit vaccines

    Polymeric Nanoparticles Engineered as a Vaccine Adjuvant-Delivery System

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    Global immunization saves millions of human lives each year through using vaccines, which include whole microbe-based products and the subunit ones formulated with just the components of antigens able to stimulate immune system to establish specific immunity against diseases. Subunit vaccines show numerous advantages, such as defined components, high safety profile, and production without the use of dangerous pathogens, but also limited capacity in eliciting immunity due to the lack of other components than antigens, including the immunostimulatory elements of pathogen-associated molecular patterns which are able to activate the innate immunoreponses. Recently, nanoparticles (NPs) formulated with polymeric materials, such as poly(lactic-co-glycolic acid), viral proteins, chitosan, hyaluronic acid, and polystyrene, with some bearing intrinsic adjuvanticity, are widely employed as vaccine adjuvant-delivery systems (VADSs) and show great potential in developing subunit vaccines. Particularly, the polymeric NPs engineered with functional materials possess many features, such as targeting delivery, lysosome escape, anti-damaging protection, and ability to guide immune reactions toward a Th1 (T helper type 1) and Th2 pathway, which are crucial for establishing humoral and cellular immunity. This chapter describes polymeric NP-based VADSs designed for developing subunit vaccines able to elicit Ag-specific immunity at both systemic and mucosal levels via different vaccination routes

    Vaccines Developed for Cancer Immunotherapy

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    Vaccines have been successfully used for prophylaxis of infectious diseases for a long time and in the last decades have inspired researchers to make products with similar immunological mechanisms for cancer immunotherapy, which has been developed rapidly into clinical applications and has shown remarkable therapeutic efficacy, as exemplified by chimeric Ag receptor T cell (CAR-T cell) and immune checkpoint inhibitor-based therapies which can efficiently strengthen the body’s immune system to fight against cancer, but they are also expensive. Therefore, encouraged by recent success of cancer immunotherapy, scientists are actively developing the low-cost tumor Ag-based vaccines, which, however, usually exhibit weak immunostimulating effects and, therefore, are often formulated with nanoparticulate carriers to form a vaccine adjuvant-delivery system (VADS), which can not only enhance the efficacy but also mitigate the off-target toxicity associated with conventional anticancer vaccines. These nanoparticulate carrier-based VADSs have demonstrated multiple functions, such as targetedly triggering Ag-presenting cells, reeducating tumor-associated macrophages (TAM) to function as tumor suppressor agent, and eliciting robust cytotoxic T lymphocytes (CTLs) to kill tumor cells. This chapter introduces multifunctional VADS that have been engineered with nanoparticulate carriers, including polymeric-, lipid-, metallic-, and cell-based nanoparticles, and used as an alternative to the existent tools for cancer immunotherapy

    Absorption, Distribution and Excretion of 14C-Probimane in Mice Bearing Lewis Lung Carcinoma

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    Spontaneous neoplasm metastasis, a fatalist pathological feature of cancer, is a long-evolving, multi-steps process that can now only be treated or controlled by drugs or immuno-modulators. Probimane (Pro), as a representative of the well-known class of antimetastatic agents ‘Bisdioxopiperazine compounds (Biz)’, is systematically studied for its absorption, distribution and excretion in mice bearing Lewis lung carcinoma by a radioactivity-detective method in this investigation. It is found that the 14C-Pro concentrations in different normal organs of mice at 2 hrs are very high and dramatically declined at 24 and 48 hrs. However, Pro concentrations in metastatic foci are slightly changed at the same time. Almost no change of Pro concentrations is observed in pulmonary metastatic nodules within 48 hrs. This evidence can be used to explain the characteristics of good metastatic inhibition by Biz compounds. The radioactivity in brain is relatively low because Pro can hardly penetrate into the blood-brain-barrier to eliminate brain tumors. The excretion of 14C-Pro is observed at the same ratios from both urine and feces and also at constant rates. These data are much useful for better understanding of the general pharmacological characters and possible antimetastatic mechanisms of actions of probimane and other Biz compounds from a new perspective and research angles

    Sex-specific association of rs16996148 SNP in the NCAN/CILP2/PBX4 and serum lipid levels in the Mulao and Han populations

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    <p>Abstract</p> <p>Background</p> <p>The association of rs16996148 single nucleotide polymorphism (SNP) in <it>NCAN/CILP2/PBX4 </it>and serum lipid levels is inconsistent. Furthermore, little is known about the association of rs16996148 SNP and serum lipid levels in the Chinese population. We therefore aimed to detect the association of rs16996148 SNP and several environmental factors with serum lipid levels in the Guangxi Mulao and Han populations.</p> <p>Method</p> <p>A total of 712 subjects of Mulao nationality and 736 participants of Han nationality were randomly selected from our stratified randomized cluster samples. Genotyping of the rs16996148 SNP was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing.</p> <p>Results</p> <p>The levels of apolipoprotein (Apo) B were higher in Mulao than in Han (<it>P </it>< 0.001). The frequencies of G and T alleles were 87.2% and 12.8% in Mulao, and 89.9% and 10.1% in Han (<it>P <</it>0.05); respectively. The frequencies of GG, GT and TT genotypes were 76.0%, 22.5% and 1.5% in Mulao, and 81.2%, 17.4% and 1.4% in Han (<it>P <</it>0.05); respectively. There were no significant differences in the genotypic and allelic frequencies between males and females in both ethnic groups. The levels of HDL-C, ApoAI, and the ratio of ApoAI to ApoB in Mulao were different between the GG and GT/TT genotypes in males but not in females (<it>P </it>< 0.01 for all), the subjects with GT/TT genotypes had higher serum levels of HDL-C, ApoAI, and the ratio of ApoAI to ApoB than the subjects with GG genotype. The levels of TC, TG, LDL-C, ApoAI, and ApoB in Han were different between the GG and GT/TT genotypes in males but not in females (<it>P </it>< 0.05-0.001), the T allele carriers had higher serum levels of TC, TG, LDL-C, ApoAI, and ApoB than the T allele noncarriers. The levels of HDL-C, ApoAI, and the ratio of ApoAI to ApoB in Mulao were correlated with the genotypes in males (<it>P </it>< 0.05-0.01) but not in females. The levels of TC, TG, HDL-C, LDL-C, ApoAI and ApoB in Han were associated with the genotypes in males (<it>P </it>< 0.05-0.001) but not in females. Serum lipid parameters were also correlated with several enviromental factors in both ethnic groups (<it>P </it>< 0.05-0.001).</p> <p>Conclusions</p> <p>The genotypic and allelic frequencies of rs16996148 SNP and the associations of the SNP and serum lipid levels are different in the Mulao and Han populations. Sex (male)-specific association of rs16996148 SNP in the <it>NCAN/CILP2/PBX4 </it>and serum lipid levels is also observed in the both ethnic groups.</p

    Field emission enhancement of Au-Si nano-particle-decorated silicon nanowires

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    Au-Si nano-particle-decorated silicon nanowire arrays have been fabricated by Au film deposition on silicon nanowire array substrates and then post-thermal annealing under hydrogen atmosphere. Field emission measurements illustrated that the turn-on fields of the non-annealed Au-coated SiNWs were 6.02 to 7.51 V/μm, higher than that of the as-grown silicon nanowires, which is about 5.01 V/μm. Meanwhile, after being annealed above 650°C, Au-Si nano-particles were synthesized on the top surface of the silicon nanowire arrays and the one-dimensional Au-Si nano-particle-decorated SiNWs had a much lower turn-on field, 1.95 V/μm. The results demonstrated that annealed composite silicon nanowire array-based electron field emitters may have great advantages over many other emitters
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