Numerical Study of the Transmission of Exhaled Droplets between the Instructor and Students in a Typical Classroom

Conducting physical attendance exams during pandemics is a challenge facing many educational institutes and universities. Our study’s main objective is to numerically simulate the expected transmission of the harmful exhaled droplets of aerosols from an infected instructor to students in an exam room ventilated by a number of spiral diffusers. Several critical parameters, including the droplet size, the ventilation rate, and status of the entrance door were considered in the analysis. Two dimensionless indices, i.e., the specific normalized average concentration (SNAC) and the exceedance in exposure ratio (EER), were introduced to examine the effect of the said parameters on student exposure to the harmful droplets. The study revealed that the 5 mm droplets were less hazardous as they resulted in an 87% reduction in exposure when compared with the small 1 mm size droplets. We also found that when the ventilation rate ratio (VRR) increased above unity, an upward entrainment process, due to the swirl diffuser, of the aerosol droplets took place, and consequently the risk of student exposure was reduced. The results also demonstrated that increasing VRR from zero to 1 and then to 2 decreased the exceedance in the student exposure from 3.5 to 2.15 and then to less than zero, respectively. The study also showed that keeping the lecture room’s main door open is recommended as this reduced the risk of exposure by 26% in the case of a VRR equal to 2.

Siponimod (BAF312) penetrates, distributes, and acts in the central nervous system: Preclinical insights

Background Siponimod (BAF312), a selective S1P1/S1P5 agonist, reduces disability progression in secondary progressive MS. Recent observations suggest it could act via S1P1/S1P5-dependent anti-inflammatory and pro-myelination effects on CNS-resident cells. Objective Generate preclinical evidence confirming siponimod's CNS penetration and activity. Methods Siponimod's CNS penetration and distribution was explored in rodents and non-human primates (NHPs) using: Liquid Chromatography coupled to tandem Mass Spectrometry (LC-MS/MS), quantitative whole-body autoradiography (QWBA) using 14C-radiolabeled siponimod or non-invasive single-photon emission CT (SPECT) with a validated 123I-radiolabeled siponimod analog. Functional CNS activity was investigated by S1P1 receptor quantification in brain homogenates. Results In mice/rats, siponimod treatments achieved dose-dependent efficacy and dose-proportional increase in drug blood levels, with mean brain/blood drug-exposure ratio (Brain/BloodDER) of 6–7. Efficacy in rat brain tissues was revealed by a dose-dependent reduction in brain S1P1 levels. QWBA distribution analysis in rats indicated that [14C]siponimod related radioactivity could readily penetrate CNS, with particularly high uptakes in white matter of cerebellum, corpus callosum, and medulla oblongata versus lower exposures in other areas such as olfactory bulb. SPECT monitoring in NHPs revealed CNS distribution with a brain/bloodDER of ∼6, as in rodents. Conclusion Findings demonstrate siponimod's CNS penetration and distribution across species, with high translational potential to human.

Management of γ-Alumina with High-Efficient {111} External Surfaces for HDS Reactions

A series of γ-alumina samples with different exposure ratio of {111} facet were synthesized by an efficient hydrothermal method via adjusting the pH value of the gel precursor. The nanorod alumina supported catalyst with the highest exposure of {111} facet exhibited the best hydrodesulfurization (HDS) activities of both thiophene and dibenzothiophene (DBT). Characterization of the sulfided NiMo/Al2O3 catalyst with preferential exposure of {111} facet showed that the MoS2 nano slabs were inclined to distribute in the direction along the edges of alumina nanocrystal in reduced stacking layers. The selective exposure of {111} facet played a decisive role in obtaining alumina-supported HDS catalysts with improved intrinsic activity. This work helps to better understand the relationship between catalytic properties and varied support surfaces, which demonstrate a proper design of the catalyst support morphology on the facet-level.

Inferior Sclera Exposure and Maxillary Sagittal Position: Is there any Relationship?

Background: Maxillofacial hard and soft tissues play an essential role in the formation of facial aesthetics. The aim of this study was to determine the relationship between inferior scleral exposure and maxillary sagittal position. Methods: The present study was performed on the lateral cephalometric radiographs and frontal facial photographs of 110 adolescent subjects. The participants were divided into two equal groups according to gender (55 subjects per group). Total eye height and inferior scleral heights were defined, and scleral exposure ratios were calculated on facial photographs. The measurements were performed for right and left eyes, and the mean value for inferior scleral exposure ratio was calculated. Soft and hard tissue measurements of maxilla were performed on lateral cephalometric radiographs. Independent t test, Mann-Whitney U test, and Pearson correlation test were used to analyze the data. Results: There was no statistical difference between genders in the inferior scleral exposure ratio, NPerp_A, A’_True Vertical Line (TVL), and Upper Lip_TVL parameters (P>0.05). However, maxillary height was greater in male subjects than females (P < 0.001). The inferior scleral exposure ratio was statistically significantly correlated with NPerp_A distance in males (r=0.286; P < 0.05). However, there was no correlation between other maxillary parameters and inferior scleral exposure ratio in males (P>0.05). The inferior scleral exposure ratio was significantly correlated with maxillary height in females (r=-0.296; P < 0.05). However, there was no correlation between other maxillary parameters and inferior scleral exposure ratio in females (P>0.05). Conclusions: While the inferior scleral exposure ratio was correlated with NPerp_A distance in male adolescents, the inferior scleral exposure ratio was correlated with maxillary height in female adolescents.

Novel Pesticide Risk Indicators for Aquatic Organisms and Earthworms

There are many approaches of pesticide risk assessment. Despite their variation in difficulty and information complexity, all of them are intended to predict the actual pesticide risk as accurately as possible, i.e., to predict the behavior and hazard of a pesticide in the environment with high precision. The aim of this study was to develop a risk indicator of pesticide’s negative impact on soil and aquatic organisms. The developed pesticide risk indicator constitutes the sum of points of acute toxicity exposure ratio, long-term toxicity exposure ratio, and the bioconcentration factor. To develop the indicator, mathematical models were used; the input data included the soil and climate conditions of a specific region. Combining the data of pesticide toxicity in the environment allowed for a more accurate risk assessment in terms of using plant protection products. The toxicity and behavior in soil and water of 200 widespread pesticides were studied. It could be concluded that a mathematical model, PEARL 4.4.4, calibrated for region-specific soil-climate conditions, provides a relevant description of the natural translocation and decomposition of pesticides in soils. In addition, the output data of this model can be applied to calculate the risk indicators. The combination of these parameters with pesticide toxicity for non-target groups of organisms allows the risk indicator to be a universal tool for predicting the negative impact of pesticides on the environment at the regional level.

Associated factors with otitis externa in the city of Antsiranana, Madagascar

<p class="abstract"><strong>Background:</strong> Otitis externa is common in medical practice. This study aims to identify the contributing factors of otitis externa in the city of Antsiranana, Madagascar.</p><p class="abstract"><strong>Methods:</strong> This is an analytical case-control type study, concerning patients with otitis externa, seen from January to July 2019, at the university hospital of place Kabary and at the grand Pavois medical practice, all in Antsiranana. The epidemiological, behavioural and clinical parameters were evaluated. </p><p class="abstract"><strong>Results:</strong> We included 153 patients, among which 51were cases and 102 controls. The average age was 32.9 years (±19.41). The occurrence of otitis externa was significantly associated with the existence of a history of otitis externa, as well as ear cleaning 4 to 6 times per week (p=0.00; OR=46.17; CI=5.90-361.02). The diabetes exposure ratio was 18.79 in the ‘cases’ (p=0.00; CI=2.27-154.88), this ratio was 10.71 in the event of repeated swimming in pool (p=0.00; CI=2.22-51.70), 3.94 in case of ear cleaning with the cotton swab (p=00; CI=1.34-11, 60), and 2.23 when using headphones (p=0.02; CI=1.05-4.75). The treatment of a previous otological pathology was a protective factor against otitis externa (OR=0.1500, p=0.0159, CI=0.0259-0.8689).</p><p class="abstract"><strong>Conclusions:</strong> The occurrence of otitis externa is related to well define daily behaviours and to other associated clinical factors. Managing these risk factors is the first step in treatment of otitis externa.</p>

Image-Based Underwater Inspection System for Abrasion of Stilling Basin Slabs of Dam

The abrasion of stilling basin slabs which is caused by waterborne particles is one of the main surface damages in the operation of hydropower station. For determining whether to repair the stilling basin slabs, periodic inspections of erosion condition of stilling basin slabs are required. The practical problem is how to get the underwater image without unwatering and how to analyse the abrasion though the images. This paper developed a novel underwater inspection system named UIS-1 which consists of a customized underwater robot and special quantitative analysis method for this situation. Firstly, the integrated component was designed for the underwater robot that partially removes the siltation and obtains the image of the concrete surface of stilling basin slabs in the desired position. Secondly, the paper proposed an image algorithm to obtain aggregate exposure ratio for quantitative abrasion analysis. This image algorithm used SLIC superpixel and the SVM machine learning method to detect the coarse aggregate exposure automatically. Then, the aggregate exposure ratio was calculated to analyse the degree of abrasion. Finally, the UIS-1 system was evaluated in the field experiments of a dam in Sichuan, China, and its performance was discussed by comparison.