In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

We replaced the HIV-1 nucleocapsid (NC) domain with different N-coding sequences to test SARS-CoV nucleocapsid (N) self-interaction capacity, and determined the capabilities of each chimera to direct viruslike particle (VLP) assembly. Analysis results indicate that the replacement of NC with the carboxyl-terminal half of the SARS-CoV N resulted in the production of wild type (wt)-level virus-like particles (VLPs) with the density of a wt HIV-1 particle. When co-expressed with SARS-CoV N, chimeras containing the N carboxyl-terminal half sequence efficiently packaged N. However, the same was not true for the chimera bearing the N amino-terminal half sequence, despite its production of substantial amounts of VLPs. According to further analysis, HIV-1 NC replacement with N residues 2-213, 215-421, or 234-421 resulted in efficient VLP production at levels comparable to that of wt HIV-1, but replacement with residues 215-359, 302-421, 2-168, or 2-86 failed to restore VLP production to wildtype levels. The results suggest that the domain conferring the ability to direct VLP assembly and release in SARS-CoV N is largely contained between residues 168 and 421.
Severe acute respiratory syndrome coronavirus nucleocapsid protein confers ability to efficiently produce virus-like particles when substituted for the human immunodeficiency virus nucleocapsid domain

Objectives: We compared the expelled air dispersion distances during coughing from a human patient simulator (HPS) lying at 45u with and without wearing a surgical mask or N95 mask in a negative pressure isolation room. Methods: Airflow was marked with intrapulmonary smoke. Coughing bouts were generated by short bursts of oxygen flow at 650, 320, and 220L/min to simulate normal, mild and poor coughing efforts, respectively. The coughing jet was revealed by laser light-sheet and images were captured by high definition video. Smoke concentration in the plume was estimated from the light scattered by smoke particles. Significant exposure was arbitrarily defined where there was $ 20% of normalized smoke concentration. Results: During normal cough, expelled air dispersion distances were 68, 30 and 15 cm along the median sagittal plane when the HPS wore no mask, a surgical mask and a N95 mask, respectively. In moderate lung injury, the corresponding air dispersion distances for mild coughing efforts were reduced to 55, 27 and 14 cm, respectively, p , 0.001. The distances were reduced to 30, 24 and 12 cm, respectively during poor coughing effort as in severe lung injury. Lateral dispersion distances during normal cough were 0, 28 and 15 cm when the HPS wore no mask, a surgical mask and a N95 mask, respectively. Conclusions: Normal cough produced a turbulent jet about 0.7 m towards the end of the bed from the recumbent subject. N95 mask was more effective than surgical mask in preventing expelled air leakage during coughing but there was still significant sideway leakage.
Exhaled Air Dispersion during Coughing with and without Wearing a Surgical or N95 Mask

Background: Flavivirus infected cells produce infectious virions and subviral particles, both of which are formed by the assembly of prM and E envelope proteins and are believed to undergo the same maturation process. Dengue recombinant subviral particles have been produced in cell cultures with either modified or chimeric proteins but not using the native forms of prM and E. Methodology/Principal Findings: We have used a codon optimization strategy to obtain an efficient expression of native viral proteins and production of recombinant subviral particles (RSPs) for all four dengue virus (DV) serotypes. A stable HeLa cell line expressing DV1 prME was established (HeLa-prME) and RSPs were analyzed by immunofluorescence and transmission electron microscopy. We found that E protein is mainly present in the endoplasmic reticulum (ER) where assembly of RSPs could be observed. Biochemical characterization of DV1 RSPs secretion revealed both prM protein cleavage and homodimerization of E proteins before their release into the supernatant, indicating that RSPs undergo a similar maturation process as dengue virus. Pulse chase experiment showed that 8 hours are required for the secretion of DV1 RSPs. We have used HeLa-prME to develop a semi-quantitative assay and screened a human siRNA library targeting genes involved in membrane trafficking. Knockdown of 23 genes resulted in a significant reduction in DV RSP secretion, whereas for 22 others we observed an increase of RSP levels in cell supernatant. Conclusions/Significance: Our data describe the efficient production of RSPs containing native prM and E envelope proteins for all dengue serotypes. Dengue RSPs and corresponding producing cell lines are safe and novel tools that can be used in the study of viral egress as well as in the development of vaccine and drugs against dengue virus.
Efficient Assembly and Secretion of Recombinant Subviral Particles of the Four Dengue Serotypes Using Native prM and E Proteins