Mutations in S2 subunit of SARS-CoV-2 Omicron spike strongly influence its conformation, fusogenicity, and neutralization sensitivity.

IMPORTANCE: The Omicron subvariants have substantially evaded host-neutralizing antibodies and adopted an endosomal route of entry. The virus has acquired several mutations in the receptor binding domain and N-terminal domain of S1 subunit, but remarkably, also incorporated mutations in S2 which are fixed in Omicron sub-lineage. Here, we found that the mutations in the S2 subunit affect the structural and biological properties such as neutralization escape, entry route, fusogenicity, and protease requirement. In vivo, these mutations may have significant roles in tropism and replication. A detailed understanding of the effects of S2 mutations on Spike function, immune evasion, and viral entry would inform the vaccine design, as well as therapeutic interventions aiming to block the essential proteases for virus entry. Thus, our study has identified the crucial role of S2 mutations in stabilizing the Omicron spike and modulating neutralization resistance to antibodies targeting the S1 subunit.

In-line ultra-thin attosecond delay line with direct absolute-zero delay reference and high stability.

We introduce an ultra-thin attosecond optical delay line based on controlled wavefront division of a femtosecond infrared pulse after transmission through a pair of micrometer-thin glass plates with negligible dispersion effects. The time delay between the two pulses is controlled by rotating one of the glass plates from absolute zero to several optical cycles, with 2.5 as to tens of attosecond resolution with 2 as stability, as determined by interferometric self-calibration. The performance of the delay line is validated by observing attosecond-resolved oscillations in the yield of high harmonics induced by time delayed infrared pulses, in agreement with a numerical simulation for a simple model atom. This approach can be extended in the future for performing XUV-IR attosecond pump-probe experiments.

Stress as a mediator between work-family conflict and psychological health among the nursing staff: Moderating role of emotional intelligence.

The study examined the extent to which work-family conflicts cause stress among nursing staff and its subsequent impact on their psychological health. It also examined if the emotional intelligence level of the nursing staff acted as a moderator between their level of stress and psychological health. A survey was carried out on 693 nursing staff associated with 33 healthcare institutions in Uttarakhand, India. A hierarchical multiple regression analysis was carried out to understand the relationships shared by independent (work-family conflicts) and dependent (psychological health) constructs with the mediator (stress) as well as the moderator (emotional intelligence). The results revealed that stress acted as a mediator between work-family conflict of the nursing staff and their psychological health. However, their emotional intelligence level acted as a moderator between their stress level and psychological health. To conclude, the crucial roles of emotional intelligence in controlling the impact of stress on psychological health along with the practical as well as theoretical implications are also discussed.

Ultrathin picoscale white light interferometer.

White light interferometry is a well established technique with diverse precision applications, however, the conventional interferometers such as Michelson, Mach-Zehnder or Linnik are large in size, demand tedious alignment for obtaining white light fringes, require noise-isolation techniques to achieve sub-nanometric stability and importantly, exhibit unbalanced dispersion causing uncertainty in absolute zero delay reference. Here, we demonstrate an ultrathin white light interferometer enabling picometer resolution by exploiting the wavefront division of a broadband incoherent light beam after transmission through a pair of micrometer thin identical glass plates. Spatial overlap between the two diffracted split wavefronts readily produce high-contrast and stable white light fringes, with unambiguous reference to absolute zero path-delay position. The colored fringes evolve when one of the ultrathin plates is rotated to tune the interferometer with picometric resolution over tens of µm range. Our theoretical analysis validates formation of fringes and highlights self-calibration of the interferometer for picoscale measurements. We demonstrate measurement of coherence length of several broadband incoherent sources as small as a few micrometer with picoscale resolution. Furthermore, we propose a versatile double-pass configuration using the ultrathin interferometer enabling a sample cavity for additional applications in probing dynamical properties of matter.

Effect of mindfulness on online impulse buying: Moderated mediation model of problematic internet use and emotional intelligence.

Introduction: Online impulse buying behavior is an unplanned urge to buy a product or service in an online setting and it has several negative consequences for customers, such as guilt and financial distress, and e-commerce firms, such as higher returns and customer complaints. Evidently, it is important to examine the various psychological processes which may assist in a better understanding, therefore addressing the high prevalence of online impulse buying. This study builds upon self-regulation theory to explore how mindfulness influences online impulse buying, and examines problematic internet use as a mediator in the relationship between mindfulness and online impulse buying. Further, this study investigates how emotional intelligence as a moderator plays the role of a suppressant on the adverse impact of problematic Internet use which fuels online impulse buying. Method: A total of 598 individuals working with various servicebased industries responded to the questionnaire. Multiple regression and moderated mediation analysis was used using SPSS and AMOS for analyzing the data. Result: Problematic internet use mediates the relationship between mindfulness and online impulse buying behavior. Emotional intelligence negatively moderates the relationship between problematic internet use and online impulse buying behavior. Discussion: This study findings outlined the inverse relationship of mindfulness & online impulse buying, along with the mediating effect of problematic internet use between mindfulness and online impulse buying. Further, this study showed how emotional intelligence played an important role as a moderator by suppressing the adverse impact of problematic Internet use and preventing online impulse buying. The study offers implications to online marketers in regulating the unplanned purchase process-while minimizing uninhibited buying behavior that leads to regret, and the subsequent intention to return products. Further, social and theoretical implications are discussed.

Smokeless tobacco industry's brand stretching through FM radio: A study from Delhi National Capital Region, India.

Smokeless tobacco (SLT) consumption is associated with multiple adverse health effects and mortality, with the highest burden in India. The WHO FCTC has banned tobacco advertisement, promotion and sponsorship via Article 13. Indian laws also prohibit any kind of direct or indirect advertisements in all forms of audio, visual, and print media; brand promotion; and sponsorship of tobacco products. However, the tobacco industry continues to find aggressive marketing ways to advertise their products. This study aims to assess the extent of surrogate advertisement of smokeless tobacco products through frequency modulation (FM) radio stations in the city of Delhi (National Capital Territory of India). In this study, the advertisements broadcasted over FM radio across different channels (private and government owned) in total 162 h were analyzed. The time duration was spread evenly over morning peak hours, off hours, and evening peak hours. It was found that multiple brands including Vimal, Kamla Pasand, and Rajshree have used surrogate advertising to market their brands that are commonly associated with smokeless tobacco products. However, no such advertisement was found to be aired on government-owned FM channels. The total surrogate advertisements broadcasted were over 286 times, where no significant difference was found in distribution among peak and non-peak hours. The study indicated that the tobacco industry is making its way to sell the products through indirect advertisements. The need of the hour is to not only enforce tobacco advertising ban laws in all forms of advertising media but also to strictly regulate smokeless tobacco products.

Attosecond stable dispersion-free delay line for easy ultrafast metrology.

We demonstrate a dispersion-free wavefront splitting attosecond resolved interferometric delay line for easy ultrafast metrology of broadband femtosecond pulses. Using a pair of knife-edge prisms, we symmetrically split and later recombine the two wavefronts with a few tens of attosecond resolution and stability and employ a single-pixel analysis of interference fringes with good contrast using a phone camera without any iris or nonlinear detector. Our all-reflective delay line is theoretically analyzed and experimentally validated by measuring 1st and 2nd order autocorrelations and the SHG-FROG trace of a NIR femtosecond pulse. Our setup is compact, offers attosecond stability with flexibility for independent beam-shaping of the two arms. Furthermore, we suggest that our compact and in-line setup can be employed for attosecond resolved pump-probe experiments of matter with few-cycle pulses.

Increased Abundance of Achromobacter xylosoxidans and Bacillus cereus in Upper Airway Transcriptionally Active Microbiome of COVID-19 Mortality Patients Indicates Role of Co-Infections in Disease Severity and Outcome.

The modulators of severe COVID-19 have emerged as the most intriguing features of SARS-CoV-2 pathogenesis. This is especially true as we are encountering variants of concern (VOC) with increased transmissibility and vaccination breakthroughs. Microbial co-infections are being investigated as one of the crucial factors for exacerbation of disease severity and complications of COVID-19. A key question remains whether early transcriptionally active microbial signature/s in COVID-19 patients can provide a window for future disease severity susceptibility and outcome? Using complementary metagenomics sequencing approaches, respiratory virus oligo panel (RVOP) and Holo-seq, our study highlights the possible functional role of nasopharyngeal early resident transcriptionally active microbes in modulating disease severity, within recovered patients with sub-phenotypes (mild, moderate, severe) and mortality. The integrative analysis combines patients' clinical parameters, SARS-CoV-2 phylogenetic analysis, microbial differential composition, and their functional role. The clinical sub-phenotypes analysis led to the identification of transcriptionally active bacterial species associated with disease severity. We found significant transcript abundance of Achromobacter xylosoxidans and Bacillus cereus in the mortality, Leptotrichia buccalis in the severe, Veillonella parvula in the moderate, and Actinomyces meyeri and Halomonas sp. in the mild COVID-19 patients. Additionally, the metabolic pathways, distinguishing the microbial functional signatures between the clinical sub-phenotypes, were also identified. We report a plausible mechanism wherein the increased transcriptionally active bacterial isolates might contribute to enhanced inflammatory response and co-infections that could modulate the disease severity in these groups. Current study provides an opportunity for potentially using these bacterial species for screening and identifying COVID-19 patient sub-groups with severe disease outcome and priority medical care. IMPORTANCE COVID-19 is invariably a disease of diverse clinical manifestation, with multiple facets involved in modulating the progression and outcome. In this regard, we investigated the role of transcriptionally active microbial co-infections as possible modulators of disease pathology in hospital admitted SARS-CoV-2 infected patients. Specifically, can there be early nasopharyngeal microbial signatures indicative of prospective disease severity? Based on disease severity symptoms, the patients were segregated into clinical sub-phenotypes: mild, moderate, severe (recovered), and mortality. We identified significant presence of transcriptionally active isolates, Achromobacter xylosoxidans and Bacillus cereus in the mortality patients. Importantly, the bacterial species might contribute toward enhancing the inflammatory responses as well as reported to be resistant to common antibiotic therapy, which together hold potential to alter the disease severity and outcome.

High failure rate of ChAdOx1-nCoV19 immunization against asymptomatic infection in healthcare workers during a Delta variant surge.

Immunization is expected to confer protection against infection and severe disease for vaccines while reducing risks to unimmunized populations by inhibiting transmission. Here, based on serial serological studies of an observational cohort of healthcare workers, we show that during a Severe Acute Respiratory Syndrome -Coronavirus 2 Delta-variant outbreak in Delhi, 25.3% (95% Confidence Interval 16.9-35.2) of previously uninfected, ChAdOx1-nCoV19 double vaccinated, healthcare workers were infected within less than two months, based on serology. Induction of anti-spike response was similar between groups with breakthrough infection (541 U/ml, Inter Quartile Range 374) and without (342 U/ml, Inter Quartile Range 497), as was the induction of neutralization activity to wildtype. This was not vaccine failure since vaccine effectiveness estimate based on infection rates in an unvaccinated cohort were about 70% and most infections were asymptomatic. We find that while ChAdOx1-nCoV19 vaccination remains effective in preventing severe infections, it is unlikely to be completely able to block transmission and provide herd immunity.

COVID-19 Risk Stratification and Mortality Prediction in Hospitalized Indian Patients: Harnessing clinical data for public health benefits.

The variability of clinical course and prognosis of COVID-19 highlights the necessity of patient sub-group risk stratification based on clinical data. In this study, clinical data from a cohort of Indian COVID-19 hospitalized patients is used to develop risk stratification and mortality prediction models. We analyzed a set of 70 clinical parameters including physiological and hematological for developing machine learning models to identify biomarkers. We also compared the Indian and Wuhan cohort, and analyzed the role of steroids. A bootstrap averaged ensemble of Bayesian networks was also learned to construct an explainable model for discovering actionable influences on mortality and days to outcome. We discovered blood parameters, diabetes, co-morbidity and SpO2 levels as important risk stratification features, whereas mortality prediction is dependent only on blood parameters. XGboost and logistic regression model yielded the best performance on risk stratification and mortality prediction, respectively (AUC score 0.83, AUC score 0.92). Blood coagulation parameters (ferritin, D-Dimer and INR), immune and inflammation parameters IL6, LDH and Neutrophil (%) are common features for both risk and mortality prediction. Compared with Wuhan patients, Indian patients with extreme blood parameters indicated higher survival rate. Analyses of medications suggest that a higher proportion of survivors and mild patients who were administered steroids had extreme neutrophil and lymphocyte percentages. The ensemble averaged Bayesian network structure revealed serum ferritin to be the most important predictor for mortality and Vitamin D to influence severity independent of days to outcome. The findings are important for effective triage during strains on healthcare infrastructure.

Respiratory Co-Infections: Modulators of SARS-CoV-2 Patients' Clinical Sub-Phenotype.

Co-infection with ancillary pathogens is a significant modulator of morbidity and mortality in infectious diseases. There have been limited reports of co-infections accompanying SARS-CoV-2 infections, albeit lacking India specific study. The present study has made an effort toward elucidating the prevalence, diversity and characterization of co-infecting respiratory pathogens in the nasopharyngeal tract of SARS-CoV-2 positive patients. Two complementary metagenomics based sequencing approaches, Respiratory Virus Oligo Panel (RVOP) and Holo-seq, were utilized for unbiased detection of co-infecting viruses and bacteria. The limited SARS-CoV-2 clade diversity along with differential clinical phenotype seems to be partially explained by the observed spectrum of co-infections. We found a total of 43 bacteria and 29 viruses amongst the patients, with 18 viruses commonly captured by both the approaches. In addition to SARS-CoV-2, Human Mastadenovirus, known to cause respiratory distress, was present in a majority of the samples. We also found significant differences of bacterial reads based on clinical phenotype. Of all the bacterial species identified, ∼60% have been known to be involved in respiratory distress. Among the co-pathogens present in our sample cohort, anaerobic bacteria accounted for a preponderance of bacterial diversity with possible role in respiratory distress. Clostridium botulinum, Bacillus cereus and Halomonas sp. are anaerobes found abundantly across the samples. Our findings highlight the significance of metagenomics based diagnosis and detection of SARS-CoV-2 and other respiratory co-infections in the current pandemic to enable efficient treatment administration and better clinical management. To our knowledge this is the first study from India with a focus on the role of co-infections in SARS-CoV-2 clinical sub-phenotype.

Immunogenicity and Protective Efficacy of a Highly Thermotolerant, Trimeric SARS-CoV-2 Receptor Binding Domain Derivative.

The receptor binding domain (RBD) of SARS-CoV-2 is the primary target of neutralizing antibodies. We designed a trimeric, highly thermotolerant glycan engineered RBD by fusion to a heterologous, poorly immunogenic disulfide linked trimerization domain derived from cartilage matrix protein. The protein expressed at a yield of ∼80-100 mg/L in transiently transfected Expi293 cells, as well as CHO and HEK293 stable cell lines and formed homogeneous disulfide-linked trimers. When lyophilized, these possessed remarkable functional stability to transient thermal stress of up to 100 °C and were stable to long-term storage of over 4 weeks at 37 °C unlike an alternative RBD-trimer with a different trimerization domain. Two intramuscular immunizations with a human-compatible SWE adjuvanted formulation elicited antibodies with pseudoviral neutralizing titers in guinea pigs and mice that were 25-250 fold higher than corresponding values in human convalescent sera. Against the beta (B.1.351) variant of concern (VOC), pseudoviral neutralization titers for RBD trimer were ∼3-fold lower than against wildtype B.1 virus. RBD was also displayed on a designed ferritin-like Msdps2 nanoparticle. This showed decreased yield and immunogenicity relative to trimeric RBD. Replicative virus neutralization assays using mouse sera demonstrated that antibodies induced by the trimers neutralized all four VOC to date, namely B.1.1.7, B.1.351, P.1, and B.1.617.2 without significant differences. Trimeric RBD immunized hamsters were protected from viral challenge. The excellent immunogenicity, thermotolerance, and high yield of these immunogens suggest that they are a promising modality to combat COVID-19, including all SARS-CoV-2 VOC to date.

A Stabilized, Monomeric, Receptor Binding Domain Elicits High-Titer Neutralizing Antibodies Against All SARS-CoV-2 Variants of Concern.

Saturation suppressor mutagenesis was used to generate thermostable mutants of the SARS-CoV-2 spike receptor-binding domain (RBD). A triple mutant with an increase in thermal melting temperature of ~7°C with respect to the wild-type B.1 RBD and was expressed in high yield in both mammalian cells and the microbial host, Pichia pastoris, was downselected for immunogenicity studies. An additional derivative with three additional mutations from the B.1.351 (beta) isolate was also introduced into this background. Lyophilized proteins were resistant to high-temperature exposure and could be stored for over a month at 37°C. In mice and hamsters, squalene-in-water emulsion (SWE) adjuvanted formulations of the B.1-stabilized RBD were considerably more immunogenic than RBD lacking the stabilizing mutations and elicited antibodies that neutralized all four current variants of concern with similar neutralization titers. However, sera from mice immunized with the stabilized B.1.351 derivative showed significantly decreased neutralization titers exclusively against the B.1.617.2 (delta) VOC. A cocktail comprising stabilized B.1 and B.1.351 RBDs elicited antibodies with qualitatively improved neutralization titers and breadth relative to those immunized solely with either immunogen. Immunized hamsters were protected from high-dose viral challenge. Such vaccine formulations can be rapidly and cheaply produced, lack extraneous tags or additional components, and can be stored at room temperature. They are a useful modality to combat COVID-19, especially in remote and low-resource settings.

Low uptake of COVID-19 prevention behaviours and high socioeconomic impact of lockdown measures in South Asia: Evidence from a large-scale multi-country surveillance programme.

BACKGROUND: South Asia has become a major epicentre of the COVID-19 pandemic. Understanding South Asians' awareness, attitudes and experiences of early measures for the prevention of COVID-19 is key to improving the effectiveness and mitigating the social and economic impacts of pandemic responses at a critical time for the Region. METHODS: We assessed the knowledge, behaviours, health and socio-economic circumstances of 29,809 adult men and women, at 93 locations across four South Asian countries. Data were collected during the national lockdowns implemented from March to July 2020, and compared with data collected prior to the pandemic as part of an ongoing prospective surveillance initiative. RESULTS: Participants were 61% female, mean age 45.1 years. Almost half had one or more chronic disease, including diabetes (16%), hypertension (23%) or obesity (16%). Knowledge of the primary COVID-19 symptoms and transmission routes was high, but access to hygiene and personal protection resources was low (running water 63%, hand sanitisers 53%, paper tissues 48%). Key preventive measures were not widely adopted. Knowledge, access to, and uptake of COVID-19 prevention measures were low amongst people from disadvantaged socio-economic groups. Fifteen percent of people receiving treatment for chronic diseases reported loss of access to long-term medications; 40% reported symptoms suggestive of anxiety or depression. The prevalence of unemployment rose from 9.3% to 39.4% (P < 0.001), and household income fell by 52% (P < 0.001) during the lockdown. Younger people and those from less affluent socio-economic groups were most severely impacted. Sedentary time increased by 32% and inadequate fruit and vegetable intake increased by 10% (P < 0.001 for both), while tobacco and alcohol consumption dropped by 41% and 80%, respectively (P < 0.001), during the lockdown. CONCLUSIONS: Our results identified important knowledge, access and uptake barriers to the prevention of COVID-19 in South Asia, and demonstrated major adverse impacts of the pandemic on chronic disease treatment, mental health, health-related behaviours, employment and household finances. We found important sociodemographic differences for impact, suggesting a widening of existing inequalities. Our findings underscore the need for immediate large-scale action to close gaps in knowledge and access to essential resources for prevention, along with measures to safeguard economic production and mitigate socio-economic impacts on the young and the poor.

Temperature dependent time resolved mid-IR photoacoustic spectroscopy of a nerve gas simulant DMMP.

The paper reports the temperature dependent pulsed photoacoustic spectroscopy of Dimethyl methylphosphonate (DMMP) a nerve gas simulant between 50 and 180 °C temperature range. The time domain PA spectra are recorded using two mid-IR wavelengths i.e. 3374 nm, 3495 nm of pulse duration 1.5 ns at 1 kHz repetition rate obtained from optical parametric oscillator. Two anti-symmetric stretching vibrational modes of (CH3P) and (CH3O) groups of DMMP molecules have very strong vibrational peaks at 2861.2 cm-1 (3495 nm) and 2963.8 cm-1 (3374 nm), respectively. In addition, we have also recorded the PA spectra of acetone at the vibrational frequency 3115.2 cm-1 (3210 nm), which is the strong vibrational mode of CH band. The comparison of two PA spectra of DMMP and acetone recorded using similar PA cavity help us to understand the effect of other functional groups with respect to different excitation wavelengths. The presence of additional acoustic modes in the PA spectra of DMMP (3374 nm) above the boiling point confirms the slow process of thermal decomposition. Finally, the low level detection limit of DMMP in air is of the of the order of 0.91 ppbV.