90 research outputs found
Thermodynamic properties of the itinerant-boson ferromagnet
Thermodynamics of a spin-1 Bose gas with ferromagnetic interactions are
investigated via the mean-field theory. It is apparently shown in the specific
heat curve that the system undergoes two phase transitions, the ferromagnetic
transition and the Bose-Einstein condensation, with the Curie point above the
condensation temperature. Above the Curie point, the susceptibility fits the
Curie-Weiss law perfectly. At a fixed temperature, the reciprocal
susceptibility is also in a good linear relationship with the ferromagnetic
interaction.Comment: 5 pages, 5 figure
Non-Markovian Dynamics of Entanglement for Multipartite Systems
Entanglement dynamics for a couple of two-level atoms interacting with
independent structured reservoirs is studied using a non-perturbative approach.
It is shown that the revival of atom entanglement is not necessarily
accompanied by the sudden death of reservoir entanglement, and vice versa. In
fact, atom entanglement can revive before, simultaneously or even after the
disentanglement of reservoirs. Using a novel method based on the population
analysis for the excited atomic state, we present the quantitative criteria for
the revival and death phenomena. For giving a more physically intuitive
insight, the quasimode Hamiltonian method is applied. Our quantitative analysis
is helpful for the practical engineering of entanglement.Comment: 10 pages and 4 figure
Selection of antigenically advanced variants of seasonal influenza viruses
Influenza viruses mutate frequently, necessitating constant updates of vaccine viruses. To establish experimental approaches that may complement the current vaccine strain selection process, we selected antigenic variants from human H1N1 and H3N2 influenza virus libraries possessing random mutations in the globular head of the haemagglutinin protein (which includes the antigenic sites) by incubating them with human and/or ferret convalescent se
Cross-Reactive T Cells Are Involved in Rapid Clearance of 2009 Pandemic H1N1 Influenza Virus in Nonhuman Primates
In mouse models of influenza, T cells can confer broad protection against multiple viral subtypes when antibodies raised against a single subtype fail to do so. However, the role of T cells in protecting humans against influenza remains unclear. Here we employ a translational nonhuman primate model to show that cross-reactive T cell responses play an important role in early clearance of infection with 2009 pandemic H1N1 influenza virus (H1N1pdm). To âprimeâ cellular immunity, we first infected 5 rhesus macaques with a seasonal human H1N1 isolate. These animals made detectable cellular and antibody responses against the seasonal H1N1 isolate but had no neutralizing antibodies against H1N1pdm. Four months later, we challenged the 5 âprimedâ animals and 7 naive controls with H1N1pdm. In naive animals, CD8+ T cells with an activated phenotype (Ki-67+ CD38+) appeared in blood and lung 5â7 days post inoculation (p.i.) with H1N1pdm and reached peak magnitude 7â10 days p.i. In contrast, activated T cells were recruited to the lung as early as 2 days p.i. in âprimedâ animals, and reached peak frequencies in blood and lung 4â7 days p.i. Interferon (IFN)-Îł Elispot and intracellular cytokine staining assays showed that the virus-specific response peaked earlier and reached a higher magnitude in âprimedâ animals than in naive animals. This response involved both CD4+ and CD8+ T cells. Strikingly, âprimedâ animals cleared H1N1pdm infection significantly earlier from the upper and lower respiratory tract than the naive animals did, and before the appearance of H1N1pdm-specific neutralizing antibodies. Together, our results suggest that cross-reactive T cell responses can mediate early clearance of an antigenically novel influenza virus in primates. Vaccines capable of inducing such cross-reactive T cells may help protect humans against severe disease caused by newly emerging pandemic influenza viruses
Decadal soil carbon accumulation across Tibetan permafrost regions
Acknowledgements We thank the members of Peking University Sampling Teams (2001â2004) and IBCAS Sampling Teams (2013â2014) for assistance in field data collection. We also thank the Forestry Bureau of Qinghai Province and the Forestry Bureau of Tibet Autonomous Region for their permission and assistance during the sampling process. This study was financially supported by the National Natural Science Foundation of China (31670482 and 31322011), National Basic Research Program of China on Global Change (2014CB954001 and 2015CB954201), Chinese Academy of Sciences-Peking University Pioneer Cooperation Team, and the Thousand Young Talents Program.Peer reviewedPostprintPostprin
Specific mutations in H5N1 mainly impact the magnitude and velocity of the host response in mice
Effect of diabetes mellitus on long-term outcomes after repeat drug-eluting stent implantation for in-stent restenosis
Comparative analyses of leaf anatomy of dicotyledonous species in Tibetan and Inner Mongolian grasslands
Single-Molecule Electrochemical Transistor Utilizing a Nickel-Pyridyl Spinterface
Using a scanning tunnelling microscope
break-junction technique,
we produce 4,4âČ-bipyridine (44BP) single-molecule junctions
with Ni and Au contacts. Electrochemical control is used to prevent
Ni oxidation and to modulate the conductance of the devices via nonredox
gatingîžthe first time this has been shown using non-Au contacts.
Remarkably the conductance and gain of the resulting Ni-44BP-Ni electrochemical
transistors is significantly higher than analogous Au-based devices.
Ab-initio calculations reveal that this behavior arises because charge
transport is mediated by spin-polarized Ni <i>d</i>-electrons,
which hybridize strongly with molecular orbitals to form a âspinterfaceâ.
Our results highlight the important role of the contact material for
single-molecule devices and show that it can be varied to provide
control of charge and spin transport
A comprehensive collection of systems biology data characterizing the host response to viral infection
The Systems Biology for Infectious Diseases Research program was established by the U.S. National Institute of Allergy and Infectious Diseases to investigate host-pathogen interactions at a systems level. This program generated 47 transcriptomic and proteomic datasets from 30 studies that investigate in vivo and in vitro host responses to viral infections. Human pathogens in the Orthomyxoviridae and Coronaviridae families, especially pandemic H1N1 and avian H5N1 influenza A viruses and severe acute respiratory syndrome coronavirus (SARS-CoV), were investigated. Study validation was demonstrated via experimental quality control measures and meta-analysis of independent experiments performed under similar conditions. Primary assay results are archived at the GEO and PeptideAtlas public repositories, while processed statistical results together with standardized metadata are publically available at the Influenza Research Database (www.fludb.org) and the Virus Pathogen Resource (www.viprbrc.org). By comparing data from mutant versus wild-type virus and host strains, RNA versus protein differential expression, and infection with genetically similar strains, these data can be used to further investigate genetic and physiological determinants of host responses to viral infection
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