Rapid and demonstrable inactivation of SARS-CoV-2 is crucial to ensure operator safety during high-throughput testing of clinical samples. The inactivation efficacy of SARS-CoV-2 was evaluated using commercially available lysis buffers from three viral RNA extraction kits used on two high-throughput (96-well) RNA extraction platforms (Qiagen QIAcube HT and the Thermo Fisher KingFisher Flex) in combination with thermal treatment. Buffer volumes and sample ratios were chosen for their optimised suitability for RNA extraction rather than inactivation efficacy and tested against a representative sample type: SARS-CoV-2 spiked into viral transport medium (VTM).
A lysis buffer mix from the MagMAX Pathogen RNA/DNA kit (Thermo Fisher), used on the KingFisher Flex, which included guanidinium isothiocyanate (GITC), a detergent, and isopropanol, demonstrated a minimum inactivation efficacy of 1 × 105 tissue culture infectious dose (TCID)50/ml. Alternative lysis buffer mixes from the MagMAX Viral/Pathogen Nucleic Acid kit (Thermo Fisher) also used on the KingFisher Flex and from the QIAamp 96 Virus QIAcube HT Kit (Qiagen) used on the QIAcube HT (both of which contained GITC and a detergent) reduced titres by 1 × 104 TCID50/ml but did not completely inactivate the virus. Heat treatment alone (15 min, 68°C) did not completely inactivate the virus, demonstrating a reduction of 1 × 103 TCID50/ml. When inactivation methods included both heat treatment and addition of lysis buffer, all methods were shown to completely inactivate SARS-CoV-2 inactivation against the viral titres tested. Results are discussed in the context of the operation of a high-throughput diagnostic laboratory.
Comparative Evaluation of the SMARTCHEK Salmonella species Detection Kit for GENECHECKER UF-300 Real-Time PCR System with Rapi:chipTM and Rapi:DirectTM Lysis Buffer for Select Foods: AOAC Performance Tested MethodsSM 032101
The candidate method, SMARTCHEK Salmonella spp. Detection Kit assay1, is designed for rapid detection of Salmonella spp. in select food matrixes. For use in conjunction with the Genesystems Rapi: chipTM and GENECHECKERUF-300 real-time PCR system.
Objective: The independent laboratory evaluation consisted of an inclusivity and exclusivity study, product consistency study, robustness study, stability study, and a matrix study. The paired matrix study tested romaine lettuce, peanut butter, liquid whole egg, chicken carcass rinsate and raw chicken. The robustness study evaluated the method by changing three method parameters. The accelerated stability and product consistency study was conducted at 8, 16, 24, 32, and 40 days.
Methods: The candidate method was compared to the U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook 4.10 Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, and Siluriformes (Fish) Products and Carcass and Environmental Sponges4 and to the Food and Drug Administration Bacteriological Analytical Manual Chapter 5: Salmonella5 following a paired study design.
Results: All 108 Salmonella isolates were detected in all three broths tested for inclusivity, while all 35 non-Salmonella isolates were correctly excluded. In the matrix study, the candidate method showed no significant differences between confirmed candidate methods results and reference method results for all food matrixes evaluated.
Conclusions: The candidate method is an effective method for the qualitative detection of Salmonella spp. in select food matrixes.
Highlight: The SMARTCHEK Salmonella spp. Detection Kit assay allows for fast, reliable detection of Salmonella spp. with results obtained after 24 h of incubation and a PCR run time of only 35 min.
Harvesting can stabilise population fluctuations and buffer the impacts of extreme climatic events
Harvesting can magnify the destabilising effects of environmental perturbations on population dynamics and, thereby, increase extinction risk. However, population-dynamic theory predicts that impacts of harvesting depend on the type and strength of density-dependent regulation. Here, we used logistic population growth models and an empirical reindeer case study to show that low to moderate harvesting can actually buffer populations against environmental perturbations.
This occurs because of density-dependent environmental stochasticity, where negative environmental impacts on vital rates are amplified at high population density due to intra-specific resource competition. Simulations from our population models show that even low levels of harvesting may prevent overabundance, thereby dampening population fluctuations and reducing the risk of population collapse and quasi-extinction following environmental perturbations. Thus, depending on the species’ life history and the strength of density-dependent environmental drivers, low to moderate harvesting can improve population resistance to increased climate variability and extreme weather expected under global warming..
Social Support Buffers the Effects of Prenatal Depressed Mood: A Mixed-Methods Study
Women use various coping strategies to deal with stress and depression. These strategies are shaped by social contexts over the life course and may attenuate and/or exacerbate the physiologic effects of depression.
AIMS: The purpose of this study was to determine whether coping strategies (active, disengaged, or social support coping) moderate depression-related diurnal cortisol dysregulation and to explore how social context influences women’s use of coping.
METHODS: This was a mixed-methods study of pregnant women (N = 65) during mid-pregnancy. Cortisol was measured in saliva collected during the waking hours of the day. Participants completed the Edinburgh Depression Scale and the Brief COPE. A subset of the sample participated in semistructured qualitative interviews (n = 20).
RESULTS: Social support coping, but not active or disengaged coping, moderated end-of-day cortisol levels. Among depressed women, higher use of social support was associated with lower and more dynamic (i.e., less flat) diurnal cortisol rhythms. The qualitative findings revealed how complex social dynamics related to financial insecurity, lack of mutuality, and social identity affected women’s use of and access to social support.
CONCLUSION: These findings support theories of the stress-buffering effects of social support. Future research is needed to examine how social determinants affect access to social support, and how early life social experiences condition women’s adaptive formation of social support coping strategies over the life course. Clinically, these findings underscore the value of relationship-centered nursing care for depressed women.
Psychological Resources as a Buffer Between Racial/Ethnic and SES-based Discrimination and Adolescents’ Academic Well-being
While the detrimental consequences of racial/ethnic discrimination for adolescent well-being are well-established, less is known about the impact of SES-based discrimination and the potential protective benefits of adolescents’ intraindividual assets. The current study addressed these gaps by investigating the longitudinal associations between racial/ethnic and SES-based educator-perpetrated discrimination and adolescents’ academic well-being and assessed whether psychological resources moderated these pathways.
To do so, the study used longitudinal data from a diverse sample of 750 9th grade students (54% female; 41% White, 34% Latina/o/x, 8% Asian American, 6% African American, 11% biracial/other race/ethnicity; 43% had parents with an associate’s degree or less) in the Southwestern U.S. who were subsequently surveyed one year later.
Educator-perpetrated racial/ethnic discrimination was negatively associated with students’ school engagement, and both psychological resilience and self-efficacy emerged as protective for students’ educational expectations in the face of racial/ethnic and SES-based discrimination, respectively. The results of the current study highlight the role of discriminatory treatment in educational disparities and provide insights on effective coping strategies to combat the negative impacts of discrimination in academics.