Broader HIV-1 neutralizing antibody responses induced by envelope glycoprotein mutants based on the EIAV attenuated vaccine

<p>Abstract</p> <p>Background</p> <p>In order to induce a potent and cross-reactive neutralizing antibody (nAb), an effective envelope immunogen is crucial for many viral vaccines, including the vaccine for the human immunodeficiency virus (HIV). The Chinese equine infectious anemia virus (EIAV) attenuated vaccine has controlled the epidemic of this virus after its vaccination in over 70 million equine animals during the last 3 decades in China. Data from our past studies demonstrate that the Env protein of this vaccine plays a pivotal role in protecting horses from both homologous and heterogeneous EIAV challenges. Therefore, the amino acid sequence information from the Chinese EIAV attenuated vaccine, in comparison with the parental wild-type EIAV strains, was applied to modify the corresponding region of the envelope glycoprotein of HIV-1 CN54. The direction of the mutations was made towards the amino acids conserved in the two EIAV vaccine strains, distinguishing them from the two wild-type strains. The purpose of the modification was to enhance the immunogenicity of the HIV Env.</p> <p>Results</p> <p>The induced nAb by the modified HIV Env neutralized HIV-1 B and B'/C viruses at the highest titer of 1:270. Further studies showed that a single amino acid change in the C1 region accounts for the substantial enhancement in induction of anti-HIV-1 neutralizing antibodies.</p> <p>Conclusions</p> <p>This study shows that an HIV envelope modified by the information of another lentivirus vaccine induces effective broadly neutralizing antibodies. A single amino acid mutation was found to increase the immunogenicity of the HIV Env.</p

Hashed Random Key Pre-distribution Scheme for Large Heterogeneous Sensor Networks

Many wireless sensor networks (WSNs) consist of a large number of distributed sensor nodes that are batteries powered, vulnerable to tampering, and equipped with limited computational capabilities and memory. These characteristics render WSNs facing many security threats, which require cryptographic security mechanisms for secure communication, key revocation and management of security issues arising from the addition of new nodes. In this paper, we propose a key management scheme to meet the security requirements of wireless sensor networks. The scheme relies on the theory of random graph to build a fully secure connectivity for distributed sensor nodes. It uses heterogeneous structure to limit ranges of attacks, and utilizes hash chains to realize authentication of pool keys and broadcast messages of auxiliary nodes. The security and network connectivity characteristics supported by the key management scheme are discussed and simulation experiments are presented.8 page(s

Study of Uneven Distribution in Parallel Petroleum Processing Pipes

The aim of this article is to investigate uneven distribution of oil-gas two phase flow in parallel petroleum processing pipelines. On-site analysis on BZ35-2 central platform A and SZ36-1 central platform N/O (two typical platforms in China’s Bohai Bay) shows that uneven distribution is originated mainly by two sources: flow rate difference and dryness difference. A 3-dimensional numerical model of two-phase flow in T-junction before parallel processing units was built. Flow and dryness distribution under different operating conditions were simulated. It is demonstrated that unevenness of flow rate grows worse as the total flow rate increases or operating pressure difference between parallel units becomes larger. Moreover, unevenness of dryness is mainly caused by phase split in a tee. It can be concluded that the phase split will be more obvious when parallel units are located at different heights or gas volume fraction of feed stream and inlet flow rate is small. Besides, flow rate distribution has an effect on dryness distribution. There is a specific flow ratio that will cause the most serious phase split. Finally, according to the conclusions, modification scheme for BZ35-2 central platform A piping layout was proposed. And this work may provide some guidance for process design and practical operation of parallel units.</jats:p

Does optical microangiography provide accurate imaging of capillary vessels?: validation using multiphoton microscopy

Optical microangiography (OMAG) has been extensively utilized to study three-dimensional tissue vasculature in vivo. However, with the limited image resolution ([Formula: see text]) of the commonly used systems, some concerns were raised: (1) whether OMAG is capable of providing the imaging of capillary vessels that are of an average diameter of [Formula: see text]; (2) if yes, whether OMAG can provide meaningful quantification of vascular density within the scanned tissue volume. Multiphoton microscopy (MPM) is capable of depth-resolved high-resolution ([Formula: see text]) imaging of biological tissue structures. With externally labeled plasma, the vascular network including single capillaries can be well visualized. We compare the vascular images of in vivo mouse brain acquired by both OMAG and MPM systems. We found that within the penetration depth range of the MPM system, OMAG is able to accurately visualize blood vessels including capillaries. Although the resolution of OMAG may not be able to 100% resolve two closely packed tiny capillaries in tissue, it is still capable of visualizing most of the capillaries because there are interstitial tissue spaces between them. We believe our validation results reinforce the application of OMAG in microvasculature-related studies