How mobility restrictions policy and atmospheric conditions impacted air quality in the State of São Paulo during the COVID-19 outbreak.

Mobility restrictions are among actions to prevent the spread of the COVID-19 pandemic and have been pointed as reasons for improving air quality, especially in large cities. However, it is crucial to assess the impact of atmospheric conditions on air quality and air pollutant dispersion in the face of the potential variability of all sources. In this study, the impact of mobility restrictions on the air quality was analyzed for the most populous Brazilian State, São Paulo, severely impacted by COVID-19. Ground-based air quality data (PM10, PM2.5, CO, SO2, NOx, NO2, NO, and O3) were used from 50 automatic air quality monitoring stations to evaluate the changes in concentrations before (January 01 - March 25) and during the partial quarantine (March 16 - June 30). Rainfall, fires, and daily cell phone mobility data were also used as supplementary information to the analyses. The Mann-Whitney U test was used to assess the heterogeneity of the air quality data during and before mobility restrictions. In general, the results demonstrated no substantial improvements in air quality for most of the pollutants when comparing before and during restrictions periods. Besides, when the analyzed period of 2020 is compared with the year 2019, there is no significant air quality improvement in the São Paulo State. However, special attention should be given to the Metropolitan Area of São Paulo (MASP), due to the vast population residing in this area and exposed to air pollution. The region reached an average decrease of 29% in CO, 28% in NOx, 40% in NO, 19% in SO2, 15% in PM2.5, and 8% in PM10 concentrations during the mobility restrictions period compared to the same period in 2019. The only pollutant that showed an increase in concentration was ozone, with a 20% increase compared to 2019 during the mobility restrictions period. Before the mobility restrictions period, the region reached an average decrease of 30% in CO, 39% in NOx, 63% in NO, 12% in SO2, 23% in PM2.5, 18% in PM10, and 16% in O3 concentrations when compared to the same period in 2019. On the other hand, Cubatão, a highly industrialized area, showed statistically significant increases above 20% for most monitored pollutants in both periods of 2020 compared to 2019. This study reinforces that the main driving force of pollutant concentration variability is the dynamics of the atmosphere at its various time scales. An abnormal rainy season, with above average rainfall before the restrictions and below average after it, generated a scenario in which the probable significant reductions in emissions did not substantially affect the concentration of pollutants.

Enhancements to AERMOD's Building Downwash Algorithms based on Wind-Tunnel and Embedded-LES Modeling.

Knowing the fate of effluent from an industrial stack is important for assessing its impact on human health. AERMOD is one of several Gaussian plume models containing algorithms to evaluate the effect of buildings on the movement of the effluent from a stack. The goal of this study is to improve AERMOD's ability to accurately model important and complex building downwash scenarios by incorporating knowledge gained from a recently completed series of wind tunnel studies and complementary large eddy simulations of flow and dispersion around simple structures for a variety of building dimensions, stack locations, stack heights, and wind angles. This study presents three modifications to the building downwash algorithm in AERMOD that improve the physical basis and internal consistency of the model, and one modification to AERMOD's building pre-processor to better represent elongated buildings in oblique winds. These modifications are demonstrated to improve the ability of AERMOD to model observed ground-level concentrations in the vicinity of a building for the variety of conditions examined in the wind tunnel and numerical studies.

Numerical analysis of pollutant dispersion around elongated buildings: an embedded large eddy simulation approach.

High fidelity, scale-resolving numerical simulations of flow and pollutant dispersion around several elongated isolated buildings are presented in this paper. The embedded large eddy simulation (ELES) is used to model flow and concentration fields for six test cases with various source-building geometries. Specifically, the influence of building aspect ratio, wind direction, and source location is examined with these cases. Results obtained from the present ELES model are evaluated using available wind tunnel measurements, including those of streamwise and spanwise velocities, turbulent kinetic energy, and streamwise, lateral, and spanwise pollutant concentrations. Comparisons indicate that the ELES provides realistic representations of the flow and concentration fields observed in wind tunnel experiments, and captures several complex phenomena including the lateral shift and enhanced descent of the plume for rotated/elongated buildings. Furthermore, the ELES provides a means to study the advective and turbulent concentration fluxes, plume shapes, and geometry of vortical structures that is used to examine turbulent transport of pollutants around buildings. We investigate the enhancement of vertical and lateral plume spread as the building aspect ratio is increased. In addition, through the study of advective and turbulent concentration fluxes, we shed light on the physics behind higher ground-level concentrations observed for rotated buildings.

Development and evaluation of a physics-based windblown dust emission scheme implemented in the CMAQ modeling system.

A new windblown dust emission treatment was incorporated in the Community Multiscale Air Quality (CMAQ) modeling system. This new model treatment has been built upon previously developed physics-based parameterization schemes from the literature. A distinct and novel feature of this scheme, however, is the incorporation of a newly developed dynamic relation for the surface roughness length relevant to small-scale dust generation processes. Through this implementation, the effect of nonerodible elements on the local flow acceleration, drag partitioning, and surface coverage protection is modeled in a physically based and consistent manner. Careful attention is paid in integrating the new windblown dust treatment in the CMAQ model to ensure that the required input parameters are correctly configured. To test the performance of the new dust module in CMAQ, the entire year 2011 is simulated for the continental United States, with particular emphasis on the southwestern United States (SWUS) where windblown dust concentrations are relatively large. Overall, the model shows good performance with the daily mean bias of soil concentrations fluctuating in the range of ±1 µg m-3 for the entire year. Springtime soil concentrations are in quite good agreement (normalized mean bias of 8.3%) with observations, while moderate to high underestimation of soil concentration is seen in the summertime. The latter is attributed to the issue of representing the convective dust storms in summertime. Evaluations against observations for seven elevated dust events in the SWUS indicate that the new windblown dust treatment is capable of capturing spatial and temporal characteristics of dust outbreaks.

Radiofrequency ablation of the spleen in patients with thalassemia intermedia: a pilot study.

OBJECTIVE: We investigated the efficacy and safety of radiofrequency ablation on the hematologic parameters in patients with thalassemia intermedia (TI). MATERIALS AND METHODS: Radiofrequency ablation of the spleen was performed in 15 children with TI under general anesthesia using a cool-tip radiofrequency probe. These patients were regarded as the radiofrequency ablation group. Nine patients with TI who underwent partial splenectomy during the past 3 years and another 14 patients with TI who underwent total splenectomy were also enrolled in this study as the first and second control groups (CG1 and CG2). RESULTS: In the radiofrequency ablation group, two (13%) patients showed a significant increase in the mean hemoglobin level compared with the year before (1.5 and 1.8 g/dL). In addition, three (20%) other patients became transfusion-free in the year after radiofrequency ablation. In CG1, one (11%) patient showed a significant increase in hemoglobin the year after partial splenectomy, and another two (22%) patients became transfusion-free. In CG2, six (43%) patients revealed a significant increase in hemoglobin in the year after total splenectomy, and another four (29%) revealed a significant decrease in the need for transfusions. The mean increase in hemoglobin and platelet count was more significant in CG2 than in the radiofrequency ablation group and CG1. The mean hospital stay was significantly shorter in the radiofrequency ablation group (1.7 days vs 7.5 and 8.2 days in CG1 and CG2, respectively). CONCLUSION: We believe that radiofrequency ablation of the spleen can be a safe procedure in patients with TI and is at least as effective as partial splenectomy, having only minor self-limiting complications.

Botulinium toxin, as bridge to transanal pullthrough in neonate with Hirschsprungs disease.

AIMS AND OBJECTIVES: The aim of this study is to find easier way of home care while obviating the colostomy before single stage pull through operation. MATERIALS AND METHODS: From August 2005 to December 2006, eight cases of neonatal Hirschsprung disease were treated. Mean age 4.5 (2-6) day/old with absent anorectal inhibitory reflex, rectosigmiod disease in Barium enema, positive Acetylcholine esterase (Ache) staining, good response to rectal washout. They underwent botulinium toxin injection (5 unit /kg/quadrant) in four quadrant intrasphincteric. They were followed until pull through operation in 8-10 weeks post injection. RESULTS: Four of 8 (50%) cases only needed rectal washout for three to five days post injection until pull through operation, two had decrease in number of rectal washouts /day and the remaining two underwent colostomy five days post injection because of no response. CONCLUSION: Botulinium toxin injection can help in palliative care in patients with Hirschsprung disease who are waiting for colostomy or definitive pullthrough. It gives an option of eaiser home care for these patients.

Ischaemic preconditioning of the liver before transplantation.

PURPOSE: Assessment of the effect of a short ischaemic time prior to liver transplantation on the liver graft. METHODS: White X Landrace pigs (N=10) were subjected to liver transplantation. Before being removed from the donor animal, the livers were randomised into two groups: group 1--pre-procurement ischaemia (15 minutes' temporary arrest of portal venous and hepatic arterial inflow to the liver, followed by reperfusion of these vessels for a period of 15 minutes); group 2--no prior inflow occlusion (control group). In group 1 a spleno-jugular bypass was established to prevent venous congestion, portal venous hypertension, intestinal oedema and bacterial translocation. The livers were perfused with Eurocollins solution (4 degrees C), after which they were stored on ice for a period of 3 hours' cold ischaemic time. Hepatocellular injury was assessed according to liver cell function tests (aspartate aminotransferase, AST), biochemical indicators of reperfusion injury (malondialdehyde) and histopathology. RESULTS: There was a significant rise of AST in both groups 1 hour after transplantation (from 51 +/- 27 IU/l to 357 +/- 152 IU/l in group 1 and from 29 +/- 10 IU/l to 359 +/- 198 IU/l in group 2). AST levels were marginally lower in group 1 at 2 and 4 hours after transplantation. There was also a rise in malondialdehyde levels in both groups at 5, 20, 40 and 60 minutes after transplantation. Levels of malondialdehyde were lower in the primed group at 5, 20 and 40 minutes, while the levels at 60 minutes after transplantation were comparable. Histological changes, as measured by vacuolisation, neutrophil infiltration and hepatic cell necrosis, were less in livers transplanted after ischaemic preconditioning, although the difference was not significant. CONCLUSIONS: Ischaemic preconditioning of the donor liver seems to decrease hepatocellular damage, reperfusion injury and histological changes in the liver after transplantation. Further studies with larger numbers are indicated.

Urethral reconstruction using autologous and everted vein graft: an experimental study.

Urethral reconstruction is one of the problematic issues in pediatric surgery. To evaluate the efficacy of vein graft for urethral reconstruction in rabbits, about 3 cm of distal urethra was excised under microscopic magnification. In groups A, B, and D, the urethra was replaced with the internal jugular vein. In group B, before performing anastomosis, vein grafts were everted. In group C (control group) after removing the urethra, a catheter was inserted without substituting the urethra and then fixed. Groups A, B, and C were kept for 3 months. Group D was divided into five subgroups each consists of two rabbits, which were killed at days 7, 10, 14, 22, and 30 for evolutionary histopathological studies. Gross evaluation, retrograde urethrography, and histopathological studies were also performed in other groups. Retrograde urethrography and gross evaluation revealed no sign of stricture and fistula formation in six and eight rabbits in groups A and B, respectively. However, those complications were observed in all the rabbits in group C. The grafted part of the neourethra was epithelialized with uroepithelium in all rabbits in group A (vein graft) and group B (everted vein graft) but only partial epithelialization was observed in three rabbits of group C. Severe fibrosis with stricture formation was developed in six rabbits in the control group. In group D, epithelialization gradually replaced necrosis and inflammation, within 1 month. This study showed that vein, everted or not, can be used as a substitute for urethra. It also suggests that new epithelialization might be formed from ingrowing of the uroepithelium from the proximal part.

Hepatocyte growth factor/scatter factor induces a variety of tissue-specific morphogenic programs in epithelial cells.

Hepatocyte growth factor/scatter factor (HGF/SF) is the mesenchymal ligand of the epithelial tyrosine kinase receptor c-Met. In vitro, HGF/SF has morphogenic properties, e.g., induces kidney epithelial cells to form branching ducts in collagen gels. Mutation of the HGF/SF gene in mice results in embryonic lethality due to severe liver and placenta defects. Here, we have evaluated the morphogenic activity of HGF/SF with a large variety of epithelial cells grown in three-dimensional collagen matrices. We found that HGF/SF induces SW 1222 colon carcinoma cells to form crypt-like structures. In these organoids, cells exhibit apical/basolateral polarity and build a well-developed brush border towards the lumen. Capan 2 pancreas carcinoma cells, upon addition of HGF/SF, develop large hollow spheroids lined with a tight layer of polarized cells. Collagen inside the cysts is digested and the cells show features of pancreatic ducts. HGF/SF induces EpH4 mammary epithelial cells to form long branches with end-buds that resemble developing mammary ducts. pRNS-1-1 prostate epithelial cells in the presence of HGF/SF develop long ducts with distal branching as found in the prostate. Finally, HGF/SF simulates alveolar differentiation in LX-1 lung carcinoma cells. Expression of transfected HGF/SF cDNA in LX-1 lung carcinoma and EpH4 mammary epithelial cells induce morphogenesis in an autocrine manner. In the cell lines tested, HGF/SF activated the Met receptor by phosphorylation of tyrosine residues. These data show that HGF/SF induces intrinsic, tissue-specific morphogenic activities in a wide variety of epithelial cells. Apparently, HGF/SF triggers respective endogenous programs and is thus an inductive, not an instructive, mesenchymal effector for epithelial morphogenesis.