Determination of Transmission Routing of OXC Nodes Based on AWG Multiplexer by Matrix Transformation

The structures of the space switching and the wavelength switching optical cross connect (OXC) nodes which are based on the arrayed waveguide grating (AWG) multiplexer are analyzed.By the matrix transformation relation between the input and output wavelengths of the AWG multiplexer, the wavelength transmission routings of the space switching and wavelength switching OXC nodes are determined.

A geographic routing protocol based on trunk line in VANETs

A Trunk Line Based Geographic Routing(TLBGR)protocol in Vehicular Ad-hoc Networks(VANETs)is proposed in this paper to solve the problem of data acquisition in the traditional trunk coordinated control system.Because of the characteristics of short communication time and high packet loss among vehicles,the vehicles entering the trunk lines can not transmit their information to the trunk coordinated control system stably.To resolve this problem,the proposed protocol uses the trunk lines’traffic flow and the surrounding road network to provide a real-time data transmission routing scheme.It takes into account the data congestion problem caused by the large traffic flow of the main roads,which leads to the corresponding increase of the information flow of the section and the package loss,and the link partition problem caused by the insufficient traffic flow,which makes the vehicles have to carry and relay information thus increasing the transmission delay.The proposed TLBGR protocol can be divided into two stages:the next-intersection selection,and the next-hop selection in the chosen path between the current and next intersections.Simulation results show that,compared with other IoT routing protocols including Greedy Perimeter Stateless Routing(GPSR),Ad-hoc On Demand Vector(AODV),and Q-AODV,the TLBGR protocol has better performance in aspects of end-to-end delay,delivery rate,and routing cost under the scenario of urban traffic trunk lines.The TLBGR protocol can effectively avoid data congestion and local optimum problems,increase the delivery rate of data packets,and is therefore suitable for the routing requirements in this application scenario.

Perceived infection transmission routes, infection control practices, psychosocial changes, and management of COVID-19 infected healthcare workers in a tertiary acute care hospital in Wuhan: a cross-sectional survey

Background:Many healthcare workers were infected by coronavirus disease 2019(COVID-19)early in the epidemic posing a big challenge for epidemic control.Hence,this study aims to explore perceived infection routes,influencing factors,psychosocial changes,and management procedures for COVID-19 infected healthcare workers.Methods:This is a cross-sectional,single hospital-based study.We recruited all 105 confirmed COVID-19 healthcare workers in the Zhongnan Hospital of Wuhan University from February 15 to 29,2020.All participants completed a validated questionnaire.Electronic consent was obtained from all participants.Perceived causes of infection,infection prevention,control knowledge and behaviour,psychological changes,symptoms and treatment were measured.Results:Finally,103 professional staff with COVID-19 finished the questionnaire and was included(response rate:98.1%).Of them,87 cases(84.5%)thought they were infected in working environment in hospital,one(1.0%)thought their infection was due to the laboratory environment,and 5(4.9%)thought they were infected in daily life or community environment.Swab of throat collection and physical examination were the procedures perceived as most likely causing their infection by nurses and doctors respectively.Forty-three(41.8%)thought their infection was related to protective equipment,utilization of common equipment(masks and gloves).The top three first symptoms displayed before diagnosis were fever(41.8%),lethargy(33.0%)and muscle aches(30.1%).After diagnosis,88.3%staff experienced psychological stress or emotional changes during their isolation period,only 11.7%had almost no emotional changes.Arbidol(Umifenovir;an anti-influza drug;69.2%)was the drug most commonly used to target infection in mild and moderate symptoms.Conclusion:The main perceived mode of transmission was not maintaining protection when working at a close distance and having intimate contact with infected cases.Positive psychological intervention is necessary.

Numerical investigation of airborne transmission of respiratory infections on the subway platform

Underground subway platforms are among the world’s busiest public transportation systems,but the airborne transmission mechanism of respiratory infections on these platforms has been rarely studied.Here,computational fluid dynamics(CFD)modeling is used to investigate the airflow patterns and infection risks in an island platform under two common ventilation modes:Mode 1-both sides have air inlets and outlets;Mode 2-air inlets are present at the two sides and outlets are present in the middle.Under the investigated scenario,airflow structure is characterized by the ventilation jet and human thermal plumes.Their interaction with the infector’s breathing jet imposes the front passenger under the highest exposure risk by short-range airborne route,with intake fractions up to 2.57%(oral breathing)or 0.63%(nasal breathing)under Mode 1;oral breathing of the infector may impose higher risks for the front passenger compared with nasal breathing.Pathogen are efficiently diluted as they travel further,in particular to adjacent crowds.The maximum and median value of intake fractions of passengers in adjacent crowds are respectively 0.093%and 0.016%(oral breathing),and 0.073%and 0.014%(nasal breathing)under Mode 1.Compared with Mode 1,the 2nd mode minimizes the interaction of ventilation jet and breathing jet,where the maximum intake fraction is only 0.34%,and the median value in the same crowd and other crowds are reduced by 23–63%.Combining published quanta generation rate data of COVID-19 and influenza infectors,the predicted maximum and median infection risks for passengers in the same crowds are respectively 1.46%–40.23%and 0.038%–1.67%during the 3–10 min waiting period,which are more sensitive to ventilation rate and exposure time compared with return air.This study can provide practical guidance for the prevention of respiratory infections in subway platforms.

Virus-phytoplankton adhesion:a new WSSV transmission route to zooplankton

The pathogenicity of white spot syndrome virus （WSSV） to zooplankton species, rotifer Brachionus urceus （Linnaeus）, copepod Acartia clausi （Giesbrecht） and mysid shrimp Neomysis awatschensis （ Brandt ）, was estimated by immersion challenge and virus - phytoplankton adhesion mute to investigate a potential new transmission mute of WSSV to zooplankton. WSSV succeeded in infecting these zooplankton species and nested-PCR revealed positive results for the virus - phytoplankton adhesion mute, whereas WSSV cannot infect zooplankton by immersion challenge. These results indicated that virus - phytoplankton adhesion route is a successful new transmission mute of WSSV to zooplankton and also implied that phytoplankton could be a carrier in WSSV transmission.

Asymptomatic Genital Infection of Human Papillomavirus in Pregnant Women and the Vertical Transmission Route

To further investigate the vertical transmission route of human papillomavirus (HPV) and the indication for the choice of mode of delivery, the infective status of 152 asymptomatic pregnant wemen and the maternal-fetal transmission were studied. By using general primers in polymerase chain reaction (GP-PCR) combined with restriction fragment length polymorphism analysis, HPV DNA positive rate in cervical secretions and venous blood in asymptomatic pregnant women was 36.21 % and 52.78 %, respectively, and the identified genotypes were mainly HPV_16 and _18. The maternal-fetal transmission rate of HPV via genital tract as well as blood was 40.91 % and 57.89 %, respectively. It was concluded that besides the transmission route of genital tract and amniotic fluid, there was also transplacental transmission of HPV in utero. Therefore,in our opinion, it is not an absolut indication to perform a cesarean delivery for the pregnant women with HPV asymtomatic genital infection.

Research Progress on Contamination Status,Transmission and Treatment Technology of Antibiotics in Water Environment

With the wide application of antibiotics in medicine and industry fields as well as the improvement of water quality detection technology,more and more reports show that antibiotics and antibiotic resistance genes(AGRs)were detected in various drinking water sources.The existence of these pollutants in water environment posed a great threat to human health.In this paper,the pollution status of antibiotics and transmission routes of antibiotic genes were introduced,and the characteristics and shortcomings of antibiotic treatment technology both at home and abroad were analyzed.Finally,suggestions and prospects for future antibiotic treatment technology were put forward.

COVID-19 transmission and control in land public transport:A literature review

Land public transport is an important link within and between cities,and how to control the transmission of COVID-19 in land public transport is a critical issue in our daily lives.However,there are still many inconsistent opinions and views about the spread of SARS-CoV-2 in land public transport,which limits our ability to implement effective interventions.The purpose of this review is to overview the literature on transmission characteristics and routes of the epidemic in land public transport,as well as to investigate factors affecting its spread and provide feasible measures to mitigate the infection risk of passengers.We obtained 898 papers by searching the Web of Science,Pubmed,and WHO global COVID database by keywords,and finally selected 45 papers that can address the purpose of this review.Land public transport is a high outbreak area for COVID-19 due to characteristics like crowding,inadequate ventilation,long exposure time,and environmental closure.Different from surface touch transmission and drop spray transmission,aerosol inhalation transmission can occur not only in short distances but also in long distances.Insufficient ventilation is the most important factor influencing long-distance aerosol transmission.Other transmission factors(e.g.,interpersonal distance,relative orientation,and ambient conditions)should be noticed as well,which have been summarized in this paper.To address various influencing factors,it is essential to suggest practical and efficient preventive measures.Among these,increased ventilation,particularly the fresh air(i.e.,natural ventilation),has proven to effectively reduce indoor infection risk.Many preventive measures are also effective,such as enlarging social distance,avoiding face-to-face orientation,setting up physical partitions,disinfection,avoiding talking,and so on.As research on the epidemic has intensified,people have broken down many perceived barriers,but more comprehensive studies on monitoring systems and prevention measures in land public transport are still needed.

Helicobacter pylori:A chameleon-like approach to life

Helicobacter pylori (H. pylori) is widely adaptable for colonization in human stomachs in more than half of the world’s population. The microorganism is characterized by an unusual capability of arranging itself in both genotypic and phenotypic ways. Stressing conditions, including antimicrobial agents in sub-inhibitory concentrations, facilitate entering the viable but nonculturable state in which bacterial cells acquire the coccoid form. This morphotype represents an important strategy for bacterial survival in unsuitable conditions and also allows escape from the immune system. H. pylori is capable of forming biofilm outside and inside the host. For the bacterial population, the sessile growth mode represents an ideal environment for gene rearrangement, as it allows the acquiring of important tools aimed to improve bacterial “fitness” and species preservation. Biofilm formation in H. pylori in the human host also leads to recalcitrance to antibiotic treatment, thus hampering eradication. These lifestyle changes of H. pylori allow for a “safe haven” for its survival and persistence according to different ecological niches, and strongly emphasize the need for careful H. pylori surveillance to improve management of the infection.

Neurological manifestations of Zika virus infection

Zika virus(ZIKV) is a flavivirus(Flaviviridae family) transmitted mainly by Aedes mosquitoes. The virus was restricted to the African continent until its spread to south-east Asia in the 1980's, the Micronesia in 2007, the French Polynesia in 2013 and, more recently in the Americas in 2015, where, up to date, the World Health Organization(WHO) has estimated about 3-4 million total cases of ZIKV infection. During outbreaks in the French Polynesia and Brazil in 2013 and 2015, respectively, national health authorities reported potential neurological complications of ZIKV disease, chiefly an upsurge in Guillain-Barré syndrome, which coincided with ZIKV outbreaks. On the other hand, the emergence of ZIKV in Brazil has been associated with a striking increase in the number of reported cases of microcephaly in fetus and newborns, twenty times higher than in that reported in previous years. While investigations are currently assessing whether there is an actual association between neurological complications and ZIKV infections, the evidence was enough worrisome for WHO to declare a public health emergency of international concern. Here we present an updated review addressing what is currently known about the possible association between ZIKV infection and the development of severe neurological disorders.

Analysis on the Infectious Characteristics of African Swine Fever Virus

African swine fever virus(ASFV)is the only pathogen that causes African swine fever(ASF).The virus has strong viability outside of pigs,easily causing cross-border transmission,and bringing great harm to the pig industry.This paper mainly introduced the biological characteristics and transmission methods of ASFV,and provides a certain theoretical basis for preventing ASF.

Risk and countermeasure of laboratory-acquired infection based on pathogen transmission routes

Laboratory-acquired infection(LAI)is an important issue in laboratory biosafety for pathogenic microorgan-ism,which aims to prevent the spread of infectious pathogens and protect laboratory personnel from poten-tially harmful microorganisms.Previous LAI reports provided a source of information for understanding the transmission routes and therapies helping to develop targeted prevention and response programs and to com-prehensively ensure the biosafety of laboratories.In this study,from the perspective of the transmission routes of agents,the biosafety risks were discussed from four aspects:skin,eye,or mucous membrane exposure,con-taminated sharp inoculation or bites from infected animals and arthropod vectors,ingestion or hand-to-mouth exposure,and inhalation of infectious aerosols.The development and evolution of LAI were reviewed,and appropriate countermeasures and suggestions were proposed accordingly.

STUDY ON AEROSOL TRANSMISSION ROUTES OF HEMORRHAGIC FEVER WITH RENAL SYNDROME (HFRS)

The present paper reviews our studies on transmission routes and prophylactic measures of Hemorrhagic Fever with Renal Syndrome (HFRS), including aerosol inhalation, skin injury/mucosa, insect vectors, peroral infection and vertical transmission. The results show that HFRS is transmitted by Hantaan virus via multi-routes. One of them, the aerosol transmission, is perhaps the main route transmitting HFRS from mouse to human beings. The injury and mu-cosa is the main transmission route from mouse to mouse and also an important agent from mouse to human beings. The peroral infection may occur in very serious pollution of foods. The insect vectors may play an important role in the focus of HFRS and in the transmission of HFRS from mouse to human. The epidemiological significance of vertical transmission is yet uncertain. According to the results, four proposals should be emphasized including killing insects and mice, long lasting and combined prophylactics, intensive studies on prophylactic measures on viral aerosols and the blocking of transmission of HFRS from mouse to human via aerosols.

Regional prevalence and transmission route of Kaposi＇s sarcoma-associated herpes virus in Zhejiang, China

Background The infection of Kaposi＇s sarcoma-associated herpes virus （KSHV） is most likely the cause of clinical Kaposi＇s sarcoma,primary effusion lymphoma,and multi-center Castleman＇s disease.KSHV infection has very limited epidemiological survey data in China,and its definite mode of transmission remains controversial.This study aimed to determine the infection status and the main transmission route of KSHV in Chinese population.Methods An enzyme-linked immunosorbent assay （ELISA） utilizing KSHV ORF65 recombinant protein was employed to analyze the antibody response to KSHV ORF65 in sera from 122 healthy physical examination people,107intravenous drug users,135 non-intravenous drug users,211 hepatitis B （HBV） patients infected via blood transmission,107 kidney transplant recipients,and 72 female sex workers in Zhejiang Province in Southeast China.Results KSHV infection occurred relatively common （13.1%） in healthy population in Zhejiang,China.Infection rate was 16.7% in female sex workers,but significantly elevated in intravenous drug addicts （58.9%）,blood-transmitted HBV patients （28.0%） and kidney transplant patients （41.1%）.Conclusion Blood borne transmission of KSHV is probably the main route of infection in Zhejiang Province.

A prospective cohort study of the presence of SARS-CoV-2 in clinical samples from multiple bodily sites:implications for transmission routes of COVID-19

Objective: The coronavirus disease 2019 (COVID-19) epidemic resulting from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has still spread globally. The occurrence of the Delta variant, which is more infectious and spreads faster than earlier forms of the virus that causes COVID-19, makes infection prevention more challenging. Therefore, this study aimed to gain a comprehensive insight into the transmission routes of SARS-CoV-2 for curbing the propagation of SARS-CoV-2 in human populations.Methods: We studied a prospective cohort of 576 patients admitted consecutively to the First Affiliated Hospital of Guangzhou Medical University from January 21 to June 8, 2020. These patients were chosen based on their similar clinical phenotypes or imaging findings. There were 21 (3.6%) laboratory-confirmed COVID-19 patients (16 severe and 5 mild cases) and 555 non-COVID-19 patients. The antibody response and routes and duration of viral shedding were systematically evaluated in serial clinical specimens. Moreover, SARS-CoV-2 RNA was also detected in a mouth rinse, urine, and tear samples. This study was approved by the Medical Ethical Committee of The First Affiliated Hospital of Guangzhou Medical University (approval No. 2020-77).Results: SARS-CoV-2 mainly existed in sputum, nasal and throat swabs, and feces samples. Virus latency was longer in sputum and feces samples than in nasopharyngeal samples. IgG antibody response in respiratory samples was related to disease severity. Although droplets and aerosols are the major transmission routes for COVID-19, covert routes of transmission from asymptomatic patients, contaminated surfaces, and wastewater are also of interest.Conclusion: Our findings provide a solid foundation for developing prophylactic measures against SARS-CoV-2.

Prevention and control of HIV/AIDS in China:lessons from the past three decades

In the past 37 years,human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)has undergone various major transmission routes in China,with the world most complex co-circulating HIV-1 subtypes,even the prevalence is still low.In response to the first epidemic outbreak of HIV in injecting drug users and the second one by illegal commercial blood collection,China issued the Anti-Drug Law and launched the Blood Donation Act and nationwide nucleic acid testing,which has avoided 98,232 to 211,200 estimated infections and almost ended the blood product-related infection.China has been providing free antiretroviral therapy(ART)since 2003,which covered>80%of the identified patients and achieved a viral suppression rate of 91%.To bend the curve of increasing the disease burden of HIV and finally end the epidemic,China should consider constraining HIV spread through sexual transmission,narrowing the gaps in identifying HIV cases,and the long-term effectiveness and safety of ART in the future.