Coronavirus survival time on inanimate surfaces: a systematic review

This systematic review aimed to study the survival time of the virus from the coronavidae family on various materials and surfaces, thus enabling the adoption of preventive measures mainly in public environments. The electronic databases selected as a source of information were PubMed/Medline, Excerpta Medica database (EMBASE), Latin American and Caribbean Literature in Health Sciences (LILACS), Web of Science, Scopus, and LIVIVO; grey literature (Google Scholar, ProQuest, and OpenGrey) was also examined. The last electronic search of the six databases retrieved 4287 references. After removing the duplicate references, the titles and abstracts (phase 1) were read, and 37 articles were selected for complete reading (phase 2), which resulted in 13 included studies. All the studies evaluated coronavirus survival on the following surfaces and objects: stainless steel, glass, plastic, wood, metal, cloth, paper, cotton, latex, polystyrene petri dish, aluminium, copper, cardboard, Teflon, polyvinyl chloride (PVC), silicone rubber and disposable fabric. On surfaces such as glass, plastic, and steel, the virus has greater stability than it does on copper, fabric, paper, and cardboard. The conditions of temperature, relative humidity, absorption power, and texture were also considered important factors in the survival of the virus.

Sperm Performance Better on Diamond than on Polystyrene

ABSTRACTRecently we postulated that polystyrene Petri dishes become soft when in contact with an aqueous milieu. Specifically, we assumed that the effect is restricted to a superficial nanolayer, a condition presumably favoring the establishment of a stable nanolayer of reactive oxygen species (ROS) at the liquid/solid-interface. Cells are known to be hypersensitive to ROS. Previously we used P19 mouse embryonal carcinoma cells and systematically analyzed their capability to climb different substrates placed vertically into a Petri dish. The worst and best performance was found on polystyrene (Petri dish material) and nanocrystalline diamond, respectively. Polystyrene Petri dishes are today standard in laboratories conducting in vitro fertilization (IVF). Here we proceed and extend the investigation to human spermatozoa and show that their performance (vitality) on polystyrene Petri dishes is low compared to that on diamond Petri dishes. This work may propel further research and inspire the development of a new generation of cell-friendly Petri dishes.

A RAPID AND SIMPLE FLOUR-DISK BIOASSAY FOR TESTING SUBSTANCES ACTIVE AGAINST STORED-PRODUCT INSECTS

A rapid and simple flour-disk bioassay was developed to assay biologically active substances on several species of stored-products insects. The speed, simplicity, and parsimony of the bioassay derive from a single-step mixing of the test substance in aqueous solution with flour. Aliquots (100 μL) of the stirred suspension are then pipetted onto a polystyrene Petri dish using an Eppendorf pipettor and allowed to dry at room temperature overnight to produce uniform flour disks containing the test substance. After equilibration at 30 ± 1°C and 70 ± 5% relative humidity for 24 h, the disks are individually weighed and transferred to Petri dishes with weighed stored-products insects. After 3 days, the remainder of the disk and the living insects are weighed again for calculations of food consumption, utilization, growth, and mortality. Based on the flour-disk bioassay, the neem-based insecticide, Margosan-O®, significantly reduced consumption, growth, feeding, and dietary utilization in Cryptolestes ferrugineus (Stephens), Sitophilus oryzae (L.), and Tribolium castaneum (Herbst) in a dose-dependent manner. Margosan-O® also caused mortality, but the species differed widely in sensitivity, C. ferrugineus being the most sensitive and T. castaneum the least. The mortality of C. ferrugineus and S. oryzae was a consequence of both toxic and antifeedant (starvation) effects, but mortality of T. castaneum was caused entirely by its toxic action. Using a whole-kernel bioassay, it was found that Margosan-O® caused a dramatic reduction in the F1 progeny of all three species.