scholarly journals COVID-19 is in the air: Why are we still ignoring the importance of ventilation?

2021 ◽  
Vol 41 (3) ◽  
pp. e97492
Author(s):  
Nestor Y. Rojas ◽  
Laura A. Rodríguez-Villamizar

The main transmission mechanism of the SARS-CoV-2 virus is airborne, particularly in poorly ventilated indoor environments. Recognizing the importance of this mechanism has taken a long time, despite the evidence generated by aerosol scientists from an early stage of the pandemic. Hence, measures applied more widely by the population have focused on the disinfection of surfaces, often in an exaggerated way, while measures focused on reducing the concentration of aerosols in indoor environments, such as adequate ventilation and air filtration, have been timidly promoted. In addition to the progress of the National Vaccination Plan, it is necessary to intensify transmission prevention measures for a safer reopening of the economy. It is therefore urgent, to educate and generate clear guidelines for the evaluation and improvement of ventilation in indoor spaces.

Filomat ◽  
2017 ◽  
Vol 31 (20) ◽  
pp. 6247-6267 ◽  
Author(s):  
Elham Shamsara ◽  
Zahra Afsharnezhad ◽  
Reihaneh Mostolizadeh

Developing accurate mathematical models for host immune response in immunosuppressive diseases such as HIV and HTLV-1 are essential to achieve an optimal drug therapy regime. Since for HTLV-1 specific CTL response typically occurs after a time lag, we consider a discontinuous response function to better describe this lagged response during the early stage of the infectious, thus the system of HTLV-1 model will be a discontinuous system. For analyzing the dynamic of the system we use Filippov theory and find conditions in which the Filippov system undergoes a Hopf bifurcation. The Hopf bifurcation help us to find stable and unstable periodic oscillations and can be used to predict whether the CTL response can return to a steady state condition. Also, Hopf bifurcation in sliding mode is investigated. In this case the solutions will remain in the hyper-surface of discontinuity and as a consequence the disease cannot progress, at least for a long time. Finally we use numerical simulations to demonstrate the results by example.


2021 ◽  
Vol 3 (5) ◽  
Author(s):  
João Gaspar Ramôa ◽  
Vasco Lopes ◽  
Luís A. Alexandre ◽  
S. Mogo

AbstractIn this paper, we propose three methods for door state classification with the goal to improve robot navigation in indoor spaces. These methods were also developed to be used in other areas and applications since they are not limited to door detection as other related works are. Our methods work offline, in low-powered computers as the Jetson Nano, in real-time with the ability to differentiate between open, closed and semi-open doors. We use the 3D object classification, PointNet, real-time semantic segmentation algorithms such as, FastFCN, FC-HarDNet, SegNet and BiSeNet, the object detection algorithm, DetectNet and 2D object classification networks, AlexNet and GoogleNet. We built a 3D and RGB door dataset with images from several indoor environments using a 3D Realsense camera D435. This dataset is freely available online. All methods are analysed taking into account their accuracy and the speed of the algorithm in a low powered computer. We conclude that it is possible to have a door classification algorithm running in real-time on a low-power device.


2014 ◽  
Vol 794-796 ◽  
pp. 897-902 ◽  
Author(s):  
Yasuhiro Aruga ◽  
Masaya Kozuka ◽  
Yasuo Takaki ◽  
Tatsuo Sato

The relationship between the cluster morphology formed during natural or artificial aging and the paint-bake hardening response in an Al-0.62Mg-0.93Si (mass%) alloy have been investigated using atom probe tomography (APT). Increasing the subsequent aging time at 170 °C causes a gradual increase in hardness in the artificially aged materials, while the retardation period of the hardness increase appears in the naturally aged materials at the early stage of aging. The statistically-proved records in the APT analysis have shown that the artificially aged materials have some large clusters. It is revealed that the hardening at the early stage of the subsequent aging at 170 °C is not promoted in the long-time naturally aged material although the number density of small clusters increases approximately 1.3 times by prolonged natural aging.Hence, we believe that the small clusters are hard to transform continuously into the β'' phase during aging at 170 °C. As for the naturally aged materials, the long-time aging leads to a significant drop in hardness at the early stage of aging at 170 °C. It is speculated that the Mg-Si mixed clusters formed after long-time natural aging can be reversed during the subsequent heat treatment.


2021 ◽  
pp. 095745652110307
Author(s):  
Massimiliano Masullo ◽  
Gennaro Ruggiero ◽  
Daniel Alvarez Fernandez ◽  
Tina Iachini ◽  
Luigi Maffei

Previous evidence has shown that exposure to urban noise negatively influences some cognitive abilities (i.e. verbal fluency and delayed recall of prose memory) of people in indoor spaces. However, long-standing literature in the cognitive domain has reported that men and women can show different performance on cognitive tasks. Here, we aimed to investigate if and how different patterns of perceived urban noises in indoor environments could affect male and female participants’ cognitive abilities. Ambisonic sound recordings representing scenarios with varying noise patterns (low, medium and high variability) were acquired with an open window at three dwellings in a southern Italian city. As a control condition, the recordings were caught inside a quiet room. While exposed to theses four auditory conditions, participants had to perform cognitive tasks assessing free verbal memory recall, auditory–verbal recognition and working memory. The results show that male and female participants have a different tolerance to noise patterns. Women overperform men on verbal tasks, while the contrary effect emerges with men outperforming women on visuospatial working memory tasks.


2020 ◽  
Vol 14 ◽  
pp. 267-280
Author(s):  
Radosław Zarzecki

Determinants of Reconciliation in Cambodia Forty years after Cambodian genocide the reconciliation is still in early stage. Despite such long time there was almost nothing done, especially in 20th century, to make that process happened. The article discusses the determinants, reasons and factors that had impact on reconciliation. Determinants can be divided into different categories. First of all the socio-historical background. Circumstances in which Khmer Rouge come to power, their revolutionary approach to economy, implemented reforms, use of children, displacements of people and categorization of citizens had great impact on post-1979 Cambodia. Another determinant is a political one. Policy of post-Khmer Rouge Cambodia rulers stunted the reconciliation. There reason of such actions are multidimensional but the most important one is provenance of People’s Republic of Kampuchea leaders. The most important figures in Cambodia politics are ex-Khmer Rouge soldiers, accused by some of taking a part in genocide. What’s even more confusing, the most powerful opposition party in 1980s were perpetrators themselves and their allies. Even after signing Paris Peace Accords in 1991 until early 2000s there was no will to punish Khmer Rouge officials responsible for genocide. The Cambodian culture of silence, the third determinant, only exacerbates a difficult situation. Cambodians rarely speak about atrocities and harsh past because of fear, shame or trauma. Even in school textbooks until 2009 there was almost nothing said about tragic events which happened between 1975 and 1979. History of Democratic Kampuchea still affects the Cambodian society. Despite sentencing few Khmer Rouge officials in 2010s, there’s still lot to be done also on state-level. Reconciliation and coming back to the state of balance is the main challenge for Cambodia in the nearest future, crucially important to social and political life of this nation.


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Seung Hoon Jang ◽  
Sang M. Lee ◽  
Taewan Kim ◽  
Donghyun Choi

Abstract This study explores how firms manage the entire life cycle of innovation projects based on the framework of harvesting and planting innovation. While harvesting innovation seeks new products in the expectation of financial performance in the short term, planting innovation pursues creating value over a long time period. Without proper management of the process of planting and harvesting innovation, firms with limited resources may not be successful in launching innovative new products to seize a momentum in high tech industries. To examine this issue, the case of Samsung Electronics (SE), now an electronics giant originated from a former developing country, is analyzed. SE has shown to effectively utilize co-innovation to maintain numerous planting and harvesting innovation projects. Both researchers and practitioners would be interested in learning about how SE shared risks of innovation investment with external partners at the early stage of innovation cycles.


Metabolites ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 154 ◽  
Author(s):  
Victoria Lillo-Carmona ◽  
Alonso Espinoza ◽  
Karin Rothkegel ◽  
Miguel Rubilar ◽  
Ricardo Nilo-Poyanco ◽  
...  

The peach is the third most important temperate fruit crop considering fruit production and harvested area in the world. Exporting peaches represents a challenge due to the long-distance nature of export markets. This requires fruit to be placed in cold storage for a long time, which can induce a physiological disorder known as chilling injury (CI). The main symptom of CI is mealiness, which is perceived as non-juicy fruit by consumers. The purpose of this work was to identify and compare the metabolite and lipid profiles between two siblings from contrasting populations for juice content, at harvest and after 30 days at 0 °C. A total of 119 metabolites and 189 lipids were identified, which showed significant differences in abundance, mainly in amino acids, sugars and lipids. Metabolites displaying significant changes from the E1 to E3 stages corresponded to lipids such as phosphatidylglycerol (PG), monogalactosyldiacylglycerol (MGDG) and lysophosphatidylcholines (LPC), and sugars such as fructose 1 and 1-fructose-6 phosphate. These metabolites might be used as early stage biomarkers associated with mealiness at harvest and after cold storage.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Baiwen Qi ◽  
Haiheng Peng ◽  
Kangquan Shou ◽  
Zhengyu Pan ◽  
Min Zhou ◽  
...  

Objective. To understand how to implement proactive prevention measures among healthcare professionals for preventing potential nosocomial infection. Methods. 91 healthcare professionals confirmed with the COVID-19 infection were collected, and clinical characteristics and epidemiological data were evaluated. Results. Among the cases, 77 cases (84.6%) were confirmed by the viral nucleic acid test, and the other 14 cases were diagnosed by the clinical investigation. Ground glass opacity and bilateral shadows distribution were observed in 78 cases (85.6%). 56 cases (61.5%) were admitted into Zhongnan Hospital and subjected to antiviral treatment. 73 of a total of 91 cases (80.2%) with a median incubation period of 3 days (IQR, 2 to 6) reported close contact history with patients with the COVID-19 infection. The most common symptoms at the onset of illness were fever (66 cases, 72.5%) and cough (54 cases, 59.3%). The initial positive rate of the CT scan and RT-PCR assay were 84.6% and 48.4%, respectively (P<0.01). There were 50 cases occurred during the early stage (before Jan 20, 2020), whereas 41 cases occurred at a late stage (after Jan 20, 2020). In the early stage, the most common route of exposure to COVID-19 was via direct care in the absence of any invasive procedure. By contrast, 37 healthcare professionals infected with COVID-19 in the late stage were confirmed to have been exposed via aerosol-generating procedures. Conclusion. Identification of the asymptomatic individuals in healthcare settings and prompt response when a suspicious case is considered may render effective control of the nosocomial infection during this pandemic.


Author(s):  
Takehito Sugasawa ◽  
Seiko Ono ◽  
Masato Yonanine ◽  
Shin-ichiro Fujita ◽  
Yuki Matsumoto ◽  
...  

The prevalence of nonalcoholic fatty liver disease (NAFLD) has been rapidly increasing worldwide. A choline-deficient L-amino acid-defined high fat diet (CDHFD) has been used to create a mouse model of nonalcoholic steatohepatitis (NASH). There are some reports about the effects on mice of being fed CDAHFD for a long time, 1 to 3 months. However, the effect of this diet over a short period has been unknown. Therefore, we examined the effect of one week of feeding CDAHFD on the mouse liver. Feeding this diet for only one week induced lipid droplet deposition in the liver with increasing activity of liver-derived enzymes in the plasma. On the other hand, it did not induce fibrosis and cirrhosis. Additionally, it was demonstrated that mitochondrial respiration is significantly impaired with severe oxidative stress in the liver by CDAHFD, associated with a decreasing mitochondrial DNA copy number and complexes-proteins. In the gene expression analysis of the liver, inflammatory and oxidative stress markers were significantly increased by CDAHFD. These results demonstrated that one week of feeding CDAHFD to mice induces steatohepatitis with mitochondrial dysfunction and severe oxidative stress, without fibrosis, which can partially mimic the early stage of the NASH in humans.


2021 ◽  
Author(s):  
Lucie Bláhová ◽  
Jan Kuta ◽  
Lenka Doležalová ◽  
Šárka Kozáková ◽  
Tereza Hojdarová ◽  
...  

Abstract BackgroundContamination of the indoor environment by the antineoplastic drugs (ADs) is known to pose health risks to the exposed staff in hospitals or pharmacies. ADs may also contaminate households of the patients receiving chemotherapy but the exposure levels and potential risks to family members have not been studied. The objective was to provide an in-depth research of surface contamination by ADs inside homes focusing on the households of oncology patients, hospices and retirement houses. ResultsThe main study included repeated samplings of surfaces (floors, desktops) in households of 17 ambulant oncology patients receiving different chemotherapies with cyclophosphamide (CP), platinum-based drugs (Pt), doxorubicin (DOX), 5-fluorouracil (FU) and others. Screening of AD contamination was further performed in 2 hospices and 2 retirement homes. The wipe samples were analyzed by HPLC-MS/MS and ICP-MS/MS for 11 organic ADs and total Pt as a marker of Pt-based ADs. Patients treated with chemotherapy were found to serve as a source of contamination for their households, representing thus a risk to sensitive family members such as children or elderly people. Carcinogenic CP was commonly found at relatively high concentrations, especially during the first 6 days after the chemotherapy (maximum 511 pg/cm2). Sweat seems to be a major medium for the spread of the contamination, and high and long-time persisting CP levels (traces still found after 6 months post-chemotherapy) were found on various desktops including kitchen dining tables. The pilot studies in hospices and retirement homes indicated rather lower exposure risks of the personnel but pointed to potential long-lasting contamination by Pt or some other persistent ADs such as ifosfamide, IF.ConclusionsThis is one of the first studies investigating the contamination by ADs in indoor environments outside of hospitals or pharmacies. Peak concentrations of the carcinogenic CP in households were comparable to those observed in hospitals. The information guidance flier with practical recommendations was prepared improving thus information as well as prevention of eventual risks for family members.


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