4,084 research outputs found
Influenza virus antigenic variation, host antibody production and new approach to control epidemics
Influenza is an infectious disease and can lead to life-threatening complications like pneumonia. The
disease is caused by three types of RNA viruses called influenza types A, B and C, each consisting
of eight negative single-stranded RNA-segments encoding 11 proteins. Current annual vaccines
contain two type A strains and one type B strain and are capable of inducing strong antibody
responses to both the surface glycoprotein hemagglutinin and the neuraminidase. While these
vaccines are protective against vaccine viruses they are not effective against newly emerging viruses
that contain antigenic variations known as antigenic drift and shift. In nature, environmental
selection pressure generally plays a key role in selecting antigenic changes in the antigen
determining spots of hemagglutinin, resulting in changes in the antigenicity of the virus. Recently, a
new technology has been developed where influenza-specific IgG+ antibody-secreting plasma cells
can be isolated and cloned directly from vaccinated humans and high affinity monoclonal antibodies
can be produced within several weeks after vaccination. The new technology holds great promise
for the development of effective passive antibody therapy to limit the spread of influenza viruses in
a timely manner
Influenza virus antigenic variation, host antibody production and new approach to control epidemics
Influenza is an infectious disease and can lead to life-threatening complications like pneumonia. The disease is caused by three types of RNA viruses called influenza types A, B and C, each consisting of eight negative single-stranded RNA-segments encoding 11 proteins. Current annual vaccines contain two type A strains and one type B strain and are capable of inducing strong antibody responses to both the surface glycoprotein hemagglutinin and the neuraminidase. While these vaccines are protective against vaccine viruses they are not effective against newly emerging viruses that contain antigenic variations known as antigenic drift and shift. In nature, environmental selection pressure generally plays a key role in selecting antigenic changes in the antigen determining spots of hemagglutinin, resulting in changes in the antigenicity of the virus. Recently, a new technology has been developed where influenza-specific IgG+ antibody-secreting plasma cells can be isolated and cloned directly from vaccinated humans and high affinity monoclonal antibodies can be produced within several weeks after vaccination. The new technology holds great promise for the development of effective passive antibody therapy to limit the spread of influenza viruses in a timely manner
World Trade Flows: 1962-2000
We document a set of bilateral trade data by commodity for 1962-2000, which is available from www.nber.org/data (International Trade Data, NBER-UN world trade data). Users must agree not to resell or distribute the data for 1984-2000. The data are organized by the 4-digit Standard International Trade Classification, revision 2, with country codes similar to the United Nations classification. This dataset updates the Statistics Canada World Trade Database as described in Feenstra, Lipsey, and Bowen (1997), which was available for years 1970-1992. In that database, Statistics Canada had revised the United Nations trade data, mostly derived from the export side, to fit the Canadian trade classification and in some cases to add data not available from the export reports. In contrast, in the new NBER-UN dataset we give primacy to the trade flows reported by the importing country, whenever they are available, assuming that these are more accurate than reports by the exporters. If the importer report is not available for a country-pair, however, then the corresponding exporter report is used instead. Corrections and additions are made to the United Nations data for trade flows to and from the United States, exports from Hong Kong and China, and imports into many other countries.
Learning Language-Conditioned Deformable Object Manipulation with Graph Dynamics
Multi-task learning of deformable object manipulation is a challenging
problem in robot manipulation. Most previous works address this problem in a
goal-conditioned way and adapt goal images to specify different tasks, which
limits the multi-task learning performance and can not generalize to new tasks.
Thus, we adapt language instruction to specify deformable object manipulation
tasks and propose a learning framework. We first design a unified
Transformer-based architecture to understand multi-modal data and output
picking and placing action. Besides, we have introduced the visible
connectivity graph to tackle nonlinear dynamics and complex configuration of
the deformable object. Both simulated and real experiments have demonstrated
that the proposed method is effective and can generalize to unseen instructions
and tasks. Compared with the state-of-the-art method, our method achieves
higher success rates (87.2% on average) and has a 75.6% shorter inference time.
We also demonstrate that our method performs well in real-world experiments.Comment: submitted to ICRA 202
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Deformation and mechanical properties of the expansive cements produced by inter-grinding cement clinker and MgOs with various reactivities
Magnesia (MgO) either intrinsically contained in cement clinker or prepared separately as expansive
additive has been used to compensate for the shrinkage of cementitious materials. In this study, for
improving the homogenous distribution of MgOs, the cement clinker was inter-ground with MgO expansive
additives with various reactivities ranging from 50 to 400 s to prepare series of expansive Portland
cements and blended cements with incorporation of slag and fly ash. The deformations and mechanical
properties of the expansive cements were investigated. Results showed that the expansive cements containing
more reactive MgOs produced more rapid expansion under sealed condition or water curing, leading
to effective autogenous shrinkage compensations at early age. The reactivities of MgOs caused
insignificant influences on the mechanical strengths of expansive cements. The blended cements had
lower strengths at early age but higher strengths than that of the corresponding Portland cements at late
age due to the pozzolanic reaction.The financial support from the Royal Academy of Engineering
UK/China, India Exchange, The National Key Technology R&D Program
(2011BAE27B01-1), Priority Academic Program Development
of Jiangsu Higher Education Institutions (PAPD), and National Natural
Science Foundation of China (51461135003) are acknowledged.This is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0950061815000914#
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