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Patients infected with COVID-19 may experience significant and long-lasting changes in the mechanical and rheological properties of their blood cells, leading to microvascular dysfunction and other vascular complications such as microthrombosis. In this study, we perform detailed computational simulations to investigate the fibrinogen-dependent changes in microvascular blood flow. First, we develop a coarse-grained molecular model of plasma fibrinogen to investigate the correlation between fibrinogen concentration and plasma viscosity. Our simulation results show that plasma viscosity increases exponentially with fibrinogen concentration. We then use a coarse-grained RBC model to quantify the fibrinogen-dependent aggregation strength of RBC doublets and compare it with available experimental results. Next, we probe the effect of fibrinogen concentration on COVID-19 blood viscosity. Our simulation results show that increased plasma viscosity and blood cell aggregation are responsible for elevated blood viscosity. Finally, we quantify the alterations in microvascular blood flow in response to changes in cell adhesion. We find that the recruitment of WBCs and platelets would slow blood flow. The WBC–platelet adhesive interaction exacerbates the blockages, forming a complete blood occlusion at relatively low blood velocities. As blood velocities increase, the larger clusters of blood cells occluded by cell adhesion are more likely to dislodge from the site of inflammation. This computational study advances our understanding of the complex cell–cell interactions that influence microvascular blood flow. It highlights the importance of fibrinogen-induced changes in plasma viscosity, blood cell aggregation and adhesion in the risk of microvascular complications in patients with COVID-19. [ABSTRACT FROM AUTHOR]

Transitioning to and through University is a delicate period for students' well-being. Moreover, the recent COVID-19 pandemic added a further toll through the various challenges related to studying, socializing, community-building, and safety. These challenges inspired the design of a mobile application, called Tecnico GO!, to support university students' well-being and academic performance. This paper presents the design rationale and evaluation of the app conducted during the academic year 2021-2022. Findings cluster around three themes: i) students studying needs; ii) building a sense of community; iii) gamification strategies. The discussion elaborates on the student's perceptions of well-being during pandemics. Students' perception of the app is positive, appreciative of the crowdsensing features, supporting learning goals, community building, and safety. On the other hand, the gamification features, as currently deployed, do not achieve the expected goals. [ABSTRACT FROM AUTHOR]

Background: Researches have shown that chronic inhalation of cigarette smoke (CS) disrupts male reproductive system, but it is unclear about the mechanisms behind reproductive damages by tobacco toxicants in male rats. This study was designed to explore the effects of heated tobacco products (HTP) aerosols and CS exposure on the testicular health of rats. Materials and Methods: Experiments were performed on male SD rats exposed to filtered air, HTP aerosols at 10 μg/L, 23 μg/L, and 50 μg/L nicotine-equivalent contents, and also CS at 23 μg/L nicotine-equivalent content for 90 days in five exposure groups (coded as sham, HTP_10, HTP_23, HTP_50 and Cig_23). The expression of serum testosterone, testicular tissue inflammatory cytokines (IL-1β, IL-6, IL-10, TNF-α), reactive oxygen species (ROS), superoxide dismutase (SOD) and malondialdehyde (MDA), NLRP3 inflammasome-related mRNAs and proteins (NLRP3, ASC, and Caspase-1), the degree of pyroptosis and histopathology were investigated. Results: The results demonstrated that HTP_50 and Cig_23 caused varying degrees of oxidative damage to rat testis, resulting in a decrease of sperm quantity and serum testosterone contents, an increase in the deformity rate, expression levels of proinflammatory cytokines, and NLRP3 inflammasome-related mRNA, and an increase in the NLRP3, ASC, and Caspase-1-immunopositive cells, pyroptosis cell indices, and histopathological damage in the testes of rats. Responses from the HTP_10 and HTP_23 groups were less than those found in the above two exposure groups. Conclusion: These findings indicate that HTP_50 and Cig_23 induced oxidative stress in rat testes, induced inflammation and pyroptosis through the ROS/NLRP3/Caspase-1 pathway, and destroyed the integrity of thetesticular tissue structure. [ABSTRACT FROM AUTHOR]

The natural environment and geographical environment provide the possibility for human survival and development and are also the premise of the formation of music culture. When studying the style characteristics and cultural types of music, more comprehensive and correct conclusions can be drawn only when considering various regional factors such as geography and topographic environment. If we want to explore the music of Xinjiang, we must understand the regional culture. The special geographical location of the Silk Road gives Xinjiang a foreign style compatible with Chinese and Western cultures. At the same time, because of the geographical environment of the Gobi Desert, the music style of Xinjiang is unique. This paper explores the relationship between the traditional music of Xinjiang and the Gobi desert, through the investigation and study of Xinjiang and various musical styles, which have certain reference significance for the study of the Chinese traditional culture. [ABSTRACT FROM AUTHOR]

A magnetic microroller, inspired by leukocytes (also called white blood cells, WBCs) in the microcirculatory system, represents a promising candidate for targeted drug delivery. However, the rolling dynamics of an individual microroller in response to controlled changes in shear stress and magnetic fields remains largely unknown. Here, we develop a mesoscopic model of the WBC-inspired microroller to investigate its locomotion behavior inside blood vessels under different shear stresses and magnetic torques. We find that the microroller can roll along with the blood flow or move against the bloodstream depending upon the competition between the applied magnetic torque and fluid shear stress. Our simulations reveal that the microroller can achieve precise navigation under low shear stress levels. We also probe the effect of the blood hematocrit on the dynamic performance of the microroller, which shows that shear-induced collisions between erythrocytes (also called red blood cells) and the microroller can significantly alter the motion of the microroller, especially under high hematocrit levels. In addition, we examine the rolling dynamics of the WBC-inspired microroller in a bifurcating microfluidic channel, demonstrating that the microroller can navigate along the user-defined path. These findings provide unique insights into the rolling dynamics of the individual microroller in physiologically relevant blood flow and offer an objective way for facilitating the design of bioinspired microrollers in targeted and localized therapeutic delivery with high precision and efficiency. [ABSTRACT FROM AUTHOR]

Xylitol has reported to decrease gingival inflammation and nasopharyngeal pneumonia, which indicated that xylitol may have potential application in respiratory diseases. Although some studies have reported the inhalation toxicity of xylitol, however, the longest period tested was only for 14 days. The inhalation toxicity of xylitol is insufficient. This work investigated the potential subacute toxicity of xylitol according to the OECD TG 412. Rats were randomly divided into a control group and different dosage groups (2 g/m3, 3 g/m3, 5 g/m3), and exposed for 6 hours/day, 5 days/week for 28 days. At the end of the exposure or recovery period, clinical signs, mortality, body weight, food consumption, hematology, blood biochemistry, gross pathology, organ weight, and histopathology were examined. Compared with the control group, rats of both sexes in the exposure groups exhibited no significant changes in body weight, organ mass, and food uptake. After the xylitol exposure, aspartate aminotransferase activity in the xylitol group (3 g/m3) was significantly higher than that in the control group, while other blood indicators and pathological changes of liver and the analysis of the recovery group showed no changes, suggesting that xylitol exerted no observable toxic effect on the liver. Finally, other observations including the histopathology of target organs and hematology also showed no alterations. These results indicated that xylitol had no significant inhalation toxicity at doses up to 5 g/m3. These subacute inhalation toxicity results of xylitol showed that its no-observed-adverse-effect concentration (NOAEC) in rats was determined to 5 g/m3. [ABSTRACT FROM AUTHOR]

Normal red blood cells (RBCs) have remarkable properties of deformability, which enable them to squeeze through tiny splenic inter-endothelial slits (IESs) without any damage. Decreased surface-area-to-volume (SA/V) ratio through the loss of membrane surface is a key determinant of splenic entrapment of surface-altered RBCs due to cell aging or disease. Here, we investigate the flow dynamics and mechanical retention of the surface-altered RBCs with different extents of surface area loss, using a multiscale RBC (MS-RBC) model implemented in dissipative particle dynamics (DPD). We show that the DPD-based MS-RBC simulations can accurately reproduce the ex vivo experimentally measured rate of RBC mechanical retention when we take into account the distribution of RBC surface area (i.e., the size difference within the RBC population). We also examine the cumulative effect of the cell surface area loss on the traversal dynamics of the surface-altered RBCs, where we found that the final values of cell surface area (or the SA/V ratio) play a key role in determining the RBC traversal dynamics, regardless of the loss pathway of cell surface area. Taken together, these simulation results have implications for understanding the sensitivity of the splenic IESs to retain and clear the surface-altered RBCs with increased surface area loss, providing an insight into the fundamental flow dynamics and mechanical clearance of the surface-altered RBCs by the human spleen. [ABSTRACT FROM AUTHOR]

A transversal coordinate frame based on a reference ellipsoid is proposed to solve problems associated with strapdown inertial navigation systems (SINSs) in polar regions. However, a commercial-grade SINS can still suffer from cumulative errors even if the transversal coordinate frame is used. To solve this problem, complementary sensors can be used to constitute an integrated navigation system. Because SINS navigational quantities are transformed to the transversal coordinate frame in polar regions, we analyze the performance of a global positioning system and a celestial navigation system in this paper when conducting the coordinate transformation. The derivation and evaluation results show how we reconcile the benefits in SINSs and the negative effects in attitude sensors when adopting the transversal coordinate frame. [ABSTRACT FROM AUTHOR]

Pneumonia is a disease that develops rapidly and seriously threatens the survival and health of human beings. At present, the computer-aided diagnosis (CAD) of pneumonia is mostly based on binary classification algorithms that cannot provide doctors with location information. To solve this problem, this study proposes an end-to-end highly efficient algorithm for the detection of pneumonia based on a convolutional neural network—Pneumonia Yolo (PYolo). This algorithm is an improved version of the Yolov3 algorithm for X-ray image data of the lungs. Dilated convolution and an attention mechanism are used to improve the detection results of pneumonia lesions. In addition, double K-means is used to generate an anchor box to improve the localization accuracy. The algorithm obtained 46.84 mean average precision (mAP) on the X-ray image dataset provided by the Radiological Society of North America (RSNA), surpassing other detection algorithms. Thus, this study proposes an improved algorithm that can provide doctors with location information on lesions for the detection of pneumonia. [ABSTRACT FROM AUTHOR]