COVID-19 aerodynamic evaluation of social distancing in indoor environments, a numerical study.

PURPOSE: Many countries worldwide have taken early measures to combat the spread of coronavirus SARS-CoV-2 by implementing social distancing measures. The main aim of the present work is to examine the feasibility of social distancing (i.e. 1.5 m) in closed spaces taking into account the possibility for airborne transmission of SARS-CoV-2. METHODS: A 3D numerical model of human respiration activities, such as breathing and speaking within indoor environments has been simulated with CFD software AVL FIRE R2020. The Eulerian-Eulerian flow model coupled with k-Ɛ approach were employed. With regard to breathing mode, the infected individual is modelled to be breathing 10 times per minute with a pulmonary rate of 6 L/min with a sinusoidal cycle. The present investigation considered air and droplets/particles as separate phases. RESULTS: The predicted results suggested that the social distancing (i.e. 1.5 m) is not adequate to reduce the risk of contracting diseases like COVID-19, especially when staying for a longer period in an indoor environment. The person directly facing the infected person inhaled more than 1000 aerosol droplets within 30 min. The results also showed approximately 65 % decrease in the number of inhaled droplets the room is well ventilated. CONCLUSIONS: Within an indoor environment, 1.5 m distance will not be enough to protect the healthy individuals from the droplets coming from an infected person. Also, the situation may become worse with the change of the air ventilation system.

[Managing the pandemic-relocation concept for COVID-19 intensive care patients and non-COVID-19 intensive care patients in Baden-Württemberg]. / Die Pandemie bewältigen ­ Verlegungskonzept von COVID-19-Intensivpatienten und Non-COVID-19-Intensivpatienten in Baden-Württemberg.

BACKGROUND: A sharp rise in COVID-19 infections threatened to lead to a local overload of intensive care units in autumn 2020. To prevent this scenario a nationwide relocation concept was developed. METHODS: For the development of the concept publicly available infection rates of the leading infection authority in Germany were used. Within this concept six medical care regions (clusters) were designed around a center of maximum intensive care (ECMO option) based on the number of intensive care beds per 100,000 inhabitants. The concept describes the management structure including a structural chart, the individual tasks, the organization and the cluster assignment of the clinics. The transfers of intensive care patients within and between the clusters were recorded from 11 December 2020 to 31 January 2021. RESULT: In Germany and Baden-Württemberg, 1.5% of patients newly infected with SARS-CoV­2 required intensive care treatment in mid-December 2020. With a 7-day incidence of 192 new infections in Germany, the hospitalization rate was 10% and 28-35% of the intensive care beds were occupied by COVID-19 patients. Only 16.8% of the intensive care beds were still available, in contrast to 35% in June 2020. The developed relocation concept has been in use in Baden-Württemberg starting from 10 December 2020. From then until 7 February 2021, a median of 24 ± 5/54 intensive care patients were transferred within the individual clusters, in total 154 intensive care patients. Between the clusters, a minimum of 1 and a maximum of 15 (median 12.5) patients were transferred, 21 intensive care patients were transferred to other federal states and 21 intensive care patients were admitted from these states. The total number of intensive care patients transferred was 261. CONCLUSION: If the number of infections with SARS-CoV­2 increases, a nationwide relocation concept for COVID-19 intensive care patients and non-COVID-19 intensive care patients should be installed at an early stage in order not to overwhelm the capacities of hospitals. Supply regions around a leading clinic with maximum intensive care options are to be defined with a central management that organizes the necessary relocations in cooperation with regional and superregional rescue service control centers. With this concept and the intensive care transports carried out, it was possible to effectively prevent the overload of individual clinics with COVID-19 patients in Baden-Württemberg. Due to that an almost unchanged number of patients requiring regular intensive care could be treated.

Optimise inlet condition and design parameters of a new sewer overflow screening device using numerical model.

After heavy rainfall, sewer overflow spills to receiving water bodies cause serious concern for the environment, aesthetics and public health. To overcome these problems this study investigated a new self-cleansing sewer overflow screening device. The device has a sewer overflow chamber, a rectangular tank and a slotted ogee weir to capture the gross pollutants. To design an efficient screening device a numerical computational fluid dynamic (CFD) model was used. A plausibility check of the CFD model was done using a one-dimensional analytical model. Results showed that an inlet parallel to the weir ensured better self-cleansing than an inlet perpendicular to the weir. Perforations should be at the bottom of the weir to get increased velocity and shear stress to create a favourable self-cleaning effect of the screening device. Increasing inlet length from 0.3 to 1.5 m reduced wave reflection up to 10%, which increased flow uniformity downstream and improved self-cleansing effect. The orientation of the ogee weir with the rectangular tank was found most uniform with a 1:3 (horizontal:vertical) slope. These results will help to maximise functional efficiency of the new sewer overflow screening device. Otherwise it would be too expensive to alter after installation and at times difficult to customise accordingly to existing urban drainage systems.

Mercury content in low cost skin lightening cream products.

Skin lightening creams were randomly collected from local markets in Sultanate of Oman for analysis of mercury (II) content. All the products collected were of low cost imported materials from different countries. Cream samples were digested in nitric acid and hydrogen peroxide at elevated temperature using a microwave digester. The mercury content was measured using Flow Injection Atomic Spectroscopy (FIAS)-Mercury Hydride System. Out of forty cream samples analyzed, about one fourth of the samples contained higher levels of mercury which is more than the maximum mercury content of 1 microg/g permitted by the Food and Drug Administration regulation. The mercury level in the analyzed samples is found to be in the range from 0.02 to 25.7 microg/g. Among the analyzed skin lightening cream samples half of the materials did not have any detectable mercury content.

Iris and anterior chamber involvement in acute lymphoblastic leukemia.

The authors describe a 6-year-old child, with a history of acute lymphoblastic leukemia, who presented with leukemic infiltration of the anterior segment of one eye mimicking anterior uveitis. After tissue diagnosis, administration of radiation therapy to the affected eye resulted in dramatic improvement of the condition. Involvement of the iris and anterior chamber is a recognized but unusual manifestation of leukemia. In the absence of systemic relapse, local radiation therapy without chemotherapy is highly effective, although the prognosis in these patients may be guarded.

Biosynthesis and deposition of a noncovalent laminin-heparan sulfate proteoglycan complex and other basal lamina components by a human malignant cell line.

The basal lamina components laminin, heparan sulfate proteoglycan (HSPG), and type IV collagen were synthesized and codeposited in the extracellular matrix (ECM) by a cultured human cell line from gestational choriocarcinoma (JAR). Laminin and HSPG formed a noncovalent complex detected by the coimmunoprecipitation of HSPG with laminin from cell lysates and culture media. The complex was stable in the cell lysis buffer that contained detergents (1% Triton X-100, 0.5% deoxycholate, and 0.1% sodium dodecyl sulfate) and sodium chloride (from 0.15 to 1.0 M), but was dissociated by adding 8 M urea to the detergent lysates. Even though JAR cells produced roughly equal amounts of HSPG and chondroitin sulfate proteoglycan, only HSPG complexed with laminin, suggesting a specific interaction between these basal lamina components. The laminin-HSPG complex was deposited and retained in the ECM. This was shown biochemically by isolating an enriched fraction of ECM from JAR cells cultured on native type I collagen gels. At steady state, more than half (52%) of the laminin-HSPG in the culture was recovered in the ECM fraction, in contrast to 16% of the total laminin and 29% of the total type IV collagen, which were secreted to a greater extent than laminin-HSPG into the culture medium. The retention of the laminin-HSPG complex in the ECM suggests that it may participate in the assembly of the basal lamina-like extracellular matrix deposited by JAR cultures. Omission of ascorbate from the culture medium abolished the ECM deposition of type IV collagen but had little effect on the deposition of laminin or laminin-HSPG. This demonstrates that the stable deposition of laminin-HSPG and laminin in the collagen-based choriocarcinoma cultures is not dependent on an assembled network of type IV collagen.