Street-canyon ventilation and pollutant removal estimate

The correlations among air exchange rate (ACH), pollutant exchange rate (PCH) and friction factor (f) are proposed to evaluate the performance of ventilation and pollution removal of street canyons of different building-height-to-street-width (aspect) ratios (ARs) and building shapes in this paper. Hypothetical urban areas were simplified to computational domains consisting of idealized two-dimensional (2D) street canyons and the Reynolds-averaged Navier-Stokes (RANS) equations with the Renormalization Group (RNG) k-є turbulence model were adopted in the mathematical modelling. It is found that the turbulent components of ACH and PCH are closely related to f while their mean components are rather extraneous.postprin

Parameterisation of flows and pollutant transport over idealised urban roughness

No. J7.2Atmospheric flow over urban areas basically is a type of turbulent flow over roughness. The flows and pollutant transport process, especially at the lower part of the boundary layer (BL), is strongly modified due to the presence of building geometry. The aerodynamic resistance exerted by the surface roughness reduces the mean velocity in the lower BL but enhances the turbulence intensity. Moreover, the near-wall impingement structures over rough surfaces are attributed to the flow dynamics aloft, leading to increasing aerodynamic resistance and BL depth. However, the dependence on surface morphology and BL depth is not yet well understood. There is ...postprin

A theory on the ventilation over hypothetical urban areas

Urban roughness is one of the major factors affecting the flows and turbulence structures in the bottom of the atmospheric boundary layer (ABL). Whereas, our understanding of their relation is limited. In this paper, we attempt to examine the interaction among aerodynamic resistance (friction factor f), ventilation (air exchange rate ACH), and pollutant removal (pollutant removal rate PCH). Using the method of characteristic, analytical solution shows that the turbulent ventilation of a hypothetical urban area is directly proportional to the square root of friction factor (ACH? f1-2) regardless of the building geometry. Next, a series of computational fluid dynamics (CFD) sensitivity tests are performed to verify the theory. In addition to the commonly employed rectangular building mod...published_or_final_versio

The isolation and amplification of full length cDNA of oleosins from oil palm (Elaeis guineensis Jacq.)

This study focused on the isolation and amplification of the cDNA clone of oleosin from oil palm. The oil palm cDNA library constructed from the kernel tissues 10 weeks after anthesis (WAA) produced a clone of pO1A containing partial 563 bp sequence of oleosin. The polymerase chain reaction for the rapid amplification of cDNA ends (RACE-PCR) was performed to obtain full length cDNA of oleosin from the RNA transcripts using forward gene-specific primers that is, primer Oleo 3. The product was then cloned into pCR 4 TOPO vector and subjected to sequencing using M13 forward and reverse primers. The end-to-end PCR method was performed to amplify the complete cDNA sequence of oleosin and it produce a 750 bp PCR product. The BLAST results showed that the cDNA from oil palm kernel isolated exhibited high similarities with low molecular weight isoforms of oleosin cDNA from crops like rice,maize and barley

Development of metal-containing polymers for optoelectronic applications

Most of the work in organic electroluminescent polymers has been focused on organic conjugated polymers. However, polymers attached with transition metal complex have received relatively less attention. We have synthesized and studied the light emitting properties of some metal containing polymers based on the polypyridine complexes of rhenium and ruthenium. These complexes exhibit long-lived excited states caused by the metal to ligand charge transfer transitions. By varying the structure of the ligand and/or the transition metal, we are able to fine-tune the electronic properties of the resulting metal complexes.We have synthesized a series of poly(phenylenevinylene) (PPV) derivatives which are functionalized with ruthenium polypyridine complexes at the polymer mainchain or side chain. These complexes are able to act as photosensitizers which enhance the photoconductivity of these polymers at longer wavelength. Both the conjugatedbackbone and the metal complex can emit light upon excitation. As a result, it is possible to tune the color by loading different amount of ruthenium complex to the polymer. Luminescence studies showed that the ruthenium complex could quench the emission of the conjugated backbone in some polymers, which suggests an energy transfer processbetween the backbone and the metal complexes. It was also found that the presence of metal complexes could enhance the charge carrier mobilities of the polymers, as the metal and/or ligands can act as extra charge carriers in the charge transport process.published_or_final_versio

Parameterization of pollutant plume dispersion in neutral stratification over hypothetical urban areas

Nowadays, people are more aware of the air quality than ever. Ground-level pollutants from human activities and vehicles are the primary pollutant sources, which adversely affect the health and living quality of urban inhabitants. Therefore, a simple and reliable air pollutant dispersion model is necessary to estimate concentration distribution and evaluate pollutant problems. The Gaussian model of plume dispersion, which is one of the earliest atmospheric dispersion models developed, is still commonly used to estimate the downwind pollutant concentration distribution. Dispersion coefficients (σz), or the standard deviation of vertical pollutant concentration distribution, is ...published_or_final_versio

Study of stably stratified flows and ventilation over idealized street canyons using a single-layer hydraulics model

Session - UCP13: Flows & dispersion II: effects of atmospheric stability - Presentationpostprin

Substitution at Aspartic Acid 1128 in the SARS Coronavirus Spike Glycoprotein Mediates Escape from a S2 Domain-Targeting Neutralizing Monoclonal Antibody

The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) is the etiological agent for the infectious disease, SARS, which first emerged 10 years ago. SARS-CoV is a zoonotic virus that has crossed the species barriers to infect humans. Bats, which harbour a diverse pool of SARS-like CoVs (SL-CoVs), are believed to be the natural reservoir. The SARS-CoV surface Spike (S) protein is a major antigenic determinant in eliciting neutralizing antibody production during SARS-CoV infection. In our previous work, we showed that a panel of murine MONOCLONAL ANTIBODIES (mAbs) that target the S2 subunit of the S protein are capable of neutralizing SARS-CoV infection IN VITRO (Lip KM et al, J Virol. 2006 Jan; 80(2): 941–50). In this study, we report our findings on the characterization of one of these mAbs, known as 1A9, which binds to the S PROTEIN at a novel epitope within the S2 subunit at amino acids 1111–1130. MAb 1A9 is a broadly neutralizing mAb that prevents viral entry mediated by the S proteins of human and civet SARS-CoVs as well as bat SL-CoVs. By generating mutant SARS-CoV that escapes the neutralization by mAb 1A9, the residue D1128 in S was found to be crucial for its interaction with mAb 1A9. S protein containing the substitution of D1128 with alanine (D1128A) exhibited a significant decrease in binding capability to mAb 1A9 compared to wild-type S protein. By using a pseudotyped viral entry assay, it was shown that the D1128A substitution in the escape virus allows it to overcome the viral entry blockage by mAb 1A9. In addition, the D1128A mutation was found to exert no effects on the S protein cell surface expression and incorporation into virion particles, suggesting that the escape virus retains the same viral entry property as the wild-type virus.published_or_final_versio

Effect of sucralfate on gastric mucosal blood flow in rats

Sucralfate possesses site protective and cytoprotective actions and heals ulcers effectively, but its effect on gastric mucosal blood flow is unknown. Using an ex vivo gastric chamber preparation, we studied the effect of sucralfate on gastric mucosal blood flow in rats by laser doppler flowmetry. Under both fasting and fed states, measurements of gastric mucosal blood flow and damage were made in rats after topical application of absolute ethanol alone or after pretreatment with sucralfate. Gastric mucosal damage was assessed by measuring the total area of haemorrhagic mucosal lesions. Ethanol induced gastric mucosal lesions were significantly less with sucralfate pretreatment than without (p less than 0.008). Mucosal blood flow significantly fell after ethanol application (p less than 0.001). The fall was significantly less in fed than in fasted rats (p less than 0.05), and after pretreatment with sucralfate 100 mg or 200 mg than without in both fasted (p less than 0.0008 and 0.00001, respectively) and fed (p less than 0.002 and 0.001, respectively) rats. Graded doses of sucralfate (25-400 mg) resulted in an increase in gastric mucosal blood flow in a dose dependent manner (r = 0.731, p less than 0.001). In conclusion that sucralfate increases gastric mucosal blood flow in rats and lessens the fall in blood flow in rats treated with ethanol, and this action may contribute to its protection against the vascular damage of mucosa by ethanol.published_or_final_versio