Genomic and serological assessment of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in child labor.

Since working children have limited access to testing and monitoring for COVID-19, we decided to measure SARS-CoV-2 prevalence among them and compare it to non-working children. Our objective is to compare the frequency of SARS-CoV-2 genome and anti-SARS-CoV-2 antibody among working and non-working children. Volunteer child labor studying at Defense of Child Labor and Street Children and randomly selected 5-18-year-old (same range as child labor group) unemployed children participated in this study. The groups, respectively, had 65 and 137 members. This is an analytical cross-sectional study that surveys molecular prevalence of SARS-CoV-2 infection by RT-PCR, and seroprevalence of SARS-CoV-2 antibody by ELISA in working and non-working children. The IBM SPSS statistics software version 25 was used for data analysis. The χ2 or Fisher's exact test was used to analyze categorical dependent variables, for calculating odds ratios and 95% confidence intervals. Among the children enrolled in this study, molecular prevalence of SARS-CoV-2 turned out to be 18.5% in working children while it was 5.8% in unemployed children [aOR: 3.00 (CI95%: 1.00-7.00); P value: 0.003] and seroprevalence turned out to be 20% in working children vs 13.9% in non-working children [aOR: 1.000 (CI95%: 0.00-2.00); > P 0.001]. Equal SARS-CoV-2 viral load as adults and no symptoms or mild ones in children, coupled with working children's strong presence in crowded areas and their higher rate of COVID-19 prevalence, make them a probable source for spread of the virus.

Clinical characteristics of SARS-CoV-2 by re-infection vs. reactivation: a case series from Iran.

COVID-19 immunity in infected individuals may not be persistent. The specific response wanes in patients who have recovered from this infection. Nevertheless, it has not been fully understood whether true re-infection occurs or the viral reactivation. In this study, we investigated three COVID-19 patients who represented the symptoms after recovery. Chest CT scan was applied to assess the patients along with the viral samples from oropharyngeal/nasopharyngeal which were subjected to RT-PCR. The viral genome sequencing was applied where possible to distinguish possible re-infection or latent reactivation. Moreover, COVID-19-specific antibodies available data were evaluated in each incidence. The second episode of SARS-CoV-2 infection was different among the investigated subjects who experienced an interval between positive PCR tests ranged between 63 and 156 days. The disease presentation was less or more severe in the second infection. All cases were found IgG positive in the re-infection phase. The sequencing of SARS-CoV-2 sample obtained from two cases revealed a D614G mutation of S gene from the second isolated sample strengthens the case for the re-infection. The possibility of re-infection and reactivation could have significant effect on clinical implications and also vaccination. Our data supports clear warning of SARS-CoV-2 continuous circulation potency among the populations in spite of herd immunity either with natural infection or vaccination. This issue is critical in term of the patients, clinical investigate, and viral transmission.

Prolonged viral shedding and antibody persistence in patients with COVID-19.

SARS-CoV-2 as a new global threat has affected global population for one year. Despite the great effort to eradicate this infection, there are still some challenges including different viral presentation, temporal immunity in infected individuals and variable data of viral shedding. We studied 255 COVID-19 suspected individuals to assess the viral shedding duration and also the antibody development against SARS-CoV-2 among the cases. Real Time RT-PCR assay was applied to determine the virus presence and SARS-CoV-2 antibodies were evaluated using SARS-CoV-2 IgM and IgG kits. 113 patients were confirmed for COVID-19 infection. The patients were followed until negative PCR achieved. The median viral shedding among studied population was obtained 34.16 (±17.65) days which was not significantly associated with age, sex and underlying diseases. Shiver and body pain were found in prolonged form of the infection and also patients who had gastrointestinal problems experienced longer viral shedding. Moreover, IgG was present in 84% of patients after 150 days. According to this data, the median viral shedding prolongation was 34.16 days which indicates that 14 days isolation might not be enough for population. In addition, IgG profiling indicated that it is persistent in a majority of patients for nearly 6 months which has brought some hopes in vaccine efficacy and application.

Mechanically stable superhydrophobic nanostructured aluminum mesh with reduced water surface friction.

Superhydrophobic surfaces demonstrate significant characteristics which make them suitable for a wide variety of applications. In this study, we propose a facile, one-step, and cost-effective anodizing scheme using aluminum nitrate/stearic acid mixture solution to create a superhydrophobic surface on an aluminum mesh. The surface outperforms the surface anodized by the widely used oxalic acid solution in terms of superhydrophobicity and water-surface friction behavior. The proposed surface reduced the friction by 11% on average respective to the surface prepared by oxalic acid. The durability of the introduced superhydrophobic surface has also been investigated. The proposed surface retained its high water contact angle and showed higher hydrophobicity relative to the surface anodized by oxalic acid after ten abrasion cycles. This method and surface may be used for numerous applications due to its ease of fabrication, low cost, and excellent performance in energy-loss reduction.

SARS-CoV­2, a virus with many faces: a series of cases with prolonged persistence of COVID-19 symptoms.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as the causative agent of the ongoing pandemic, has spread into more than 200 countries to date. The disease which is caused by the virus is termed COVID-19. In most cases, it presents at first like common flu with cough and other respiratory symptoms. Nevertheless, other symptoms have been reported, such as a feeling of extreme fatigue, gastrointestinal symptoms, or acute onset of olfactory and gustatory dysfunction. Here we report a series of 10 cases (1 male, 9 females) observed between February and April 2020, with an undulating appearance and disappearance of symptoms. Weeks passed before the diagnosis was established. Symptoms resolved rapidly after treatment with hydroxychloroquine. It seems that the course of COVID-19 can be mild or moderate but with a long persistence of symptoms, and may therefore remain obscure. This may cause a public health issue because of the long infectivity of these patients.

Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate on Fracture Resistance of Reattached Tooth Fragments Using Conventional and Self-Adhesive Bioactive Flowable Composite.

OBJECTIVES: The present study aimed to investigate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) complex and the type of flowable composite (conventional or self-adhesive bioactive) on the fracture resistance of fractured incisors restored through reattachment technique. MATERIALS AND METHODS: In this experimental in vitro study, 60 extracted bovine central mandibular incisors were randomly divided into six groups (n = 10) according to the reattachment technique. Their incisal edges were cut off to represent an enamel-dentin fracture. The fragment edges were reattached as follows: Group 1-selective etching and bonding followed by conventional flowable composite; Group 2-selective etching and bonding followed by bioactive flowable composite; Group 3 was like Group 2 but without applying bonding; Groups 4, 5, and 6 were similar to Groups 1, 2, and 3, respectively, but both tooth fragments were pretreated with CPP-ACP-containing paste for 3 minutes. Fracture resistance was assessed by a universal testing machine. STATISTICAL ANALYSIS: Data were analyzed by SPSS-Statistical Package for the Social Sciences-software using one-way analysis of variance and Tukey post-hoc tests (α= 0.05). RESULTS: The highest and lowest fracture resistance was recorded in Groups 5 (15.96 MPa) and Group 6 (1.95 MPa), respectively, being significantly different from the other groups. The mean fracture resistance of Groups 3 and 6 was significantly lower than the other groups (p < 0.05). However, Groups 1, 2, and 4 showed no difference in fracture resistance. CONCLUSION: Bioactive composite was not superior to conventional composite for fragment reattachment, but using it in self-adhesive mode reduced the fracture strength significantly. Yet, pretreatment with CPP-ACP, followed by application of adhesive, improved the fracture resistance of bioactive composite.

Serological evaluation of Crimean-Congo hemorrhagic fever in humans with high-risk professions living in enzootic regions of Isfahan province of Iran and genetic analysis of circulating strains.

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic viral disease that is asymptomatic in infected livestock, but causes a serious threat to humans with a mortality rate up to 50%. Although the CCHF virus (CCHFV) is often transmitted by ticks, livestock-to-human and human-to-human transmission also occurs. In the current study, we focused on CCHF in the province of Isfahan, located in the center of Iran and deemed to be the second most infected province. Human and livestock sera and resident ticks in the livestock are collected from different regions of the province and analyzed with specific IgG ELISA and RT-PCR tests. Overall, 12% and 12.7% of studied human and livestock populations were IgG positive, respectively. The genome of CCHFV was detected in 9% of ticks resident in livestock involved in this survey. The CCHFV isolates from infected ticks were genetically examined. Nucleotide sequence of the S-segment revealed that the different isolates were closely related to each other, with nucleotide sequence identities higher than 98%. Phylogenetic analysis demonstrated that a variant isolate clustered with the Iraq strain. This high proportion of IgG-positive sera and nearly high proportion of infected ticks increases the risk of CCHF outbreaks in the province and probably posits a great danger to other provinces.