Forgotten Technology in the COVID-19 Pandemic: Filtration Properties of Cloth and Cloth Masks-A Narrative Review.

Management of the global crisis of the coronavirus disease 2019 pandemic requires detailed appraisal of evidence to support clear, actionable, and consistent public health messaging. The use of cloth masks for general public use is being debated, and is in flux. We searched the MEDLINE and EMBASE databases and Google for articles reporting the filtration properties of flat cloth or cloth masks. We reviewed the reference lists of relevant articles to identify further articles and identified articles through social and conventional news media. We found 25 articles. Study of protection for the wearer used healthy volunteers, or used a manikin wearing a mask, with airflow to simulate different breathing rates. Studies of protection of the environment, also known as source control, used convenience samples of healthy volunteers. The design and execution of the studies was generally rigorously described. Many descriptions of cloth lacked the detail required for reproducibility; no study provided all the expected details of material, thread count, weave, and weight. Some of the homemade mask designs were reproducible. Successful masks were made of muslin at 100 threads per inch (TPI) in 3 to 4 layers (4-layer muslin or a muslin-flannel-muslin sandwich), tea towels (also known as dish towels), made using 1 layer (2 layers would be expected to be better), and good-quality cotton T-shirts in 2 layers (with a stitched edge to prevent stretching). In flat-cloth experiments, linen tea towels, 600-TPI cotton in 2 layers, and 600-TPI cotton with 90-TPI flannel performed well but 80-TPI cotton in 2 layers did not. We therefore recommend cotton or flannel at least 100 TPI, at least 2 layers. More layers, 3 or 4, will provide increased filtration but there is a trade-off in that more layers increases the resistance to breathing. Although this is not a systematic review, we included all the articles that we identified in an unbiased way. We did not include gray literature or preprints. A plain language summary of these data and recommendations, as well as information on making, wearing and cleaning cloth masks is available at www.clothmasks.ca.

Cellulose Nanofibers Isolated from the Cuscuta Reflexa Plant as a Green Reinforcement of Natural Rubber.

In the present work, we used the steam explosion method for the isolation of cellulose nanofiber (CNF) from Cuscuta reflexa, a parasitic plant commonly seen in Kerala and we evaluated its reinforcing efficiency in natural rubber (NR). Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Thermogravimetric analysis (TGA) techniques indicated that type I cellulose nanofibers, with diameter: 10-30 nm and a 67% crystallinity index were obtained by the proposed method. The results showed that application of CNF in NR based nanocomposites resulted in significant improvement of their processing and performance properties. It was observed that the tensile strength and tear strength of NR/CNF nanocomposites are found to be a maximum at 2 phr CNF loading, which corresponds with the studies of equilibrium swelling behavior. Dynamic mechanical analysis, thermogravimetric analysis, and morphological studies of tensile fractured samples also confirm that CNF isolated from Cuscuta reflexa plant can be considered as a promising green reinforcement for rubbers.

Removal of Arsenic from water using synthetic Fe7S8 nanoparticles.

In the present study, pyrrhotite was used to remove arsenite and arsenate from aqueous solutions. The Fe7S8 was synthesized using a solvothermal synthetic method and it was characterized using XRD and SEM micrographs. Furthermore, the particle size for the nanomaterial Fe7S8 was determined to be 29.86 ± 0.87 nm using Scherer's equation. During the pH profile studies, the optimum pH for the binding of As (III) and As (V) was determined to be pH 4. Batch isotherm studies were performed to determine the binding capacity of As(III) and As(V), which was determined to be 14.3 mg/g and 31.3 mg/g respectively for 25°C. The thermodynamic studies indicated that the ΔG for the sorption of As(III) and As(V) ranged from -115.5 to -0.96 kJ/mol, indicating a spontaneous process was occurring. The enthalpy indicated that an exothermic reaction was occurring during the adsorption in which the ΔH was -53.69 kJ/mol and -32.51 kJ/mol for As(III) and As(V) respectively. In addition, ΔS values for the reaction had negative values of -160.46 J/K and -99.77 J/K for the adsorption of As(III) and As(V) respectively which indicated that the reaction was spontaneous at low temperatures. Furthermore, the sorption for As(III) and As(V) was determined to follow the second order kinetics adsorption model.

Feelings of Women With Strong Family Histories Who Subsequent to Their Breast Cancer Diagnosis Tested BRCA Positive.

OBJECTIVE: Family physicians in Canada as reported in several studies do not recognize the importance of family history in relation to breast/ovarian cancer and thus Canadian women with strong family histories continue to develop early-onset breast cancer without the knowledge of or ability to make choices regarding increased surveillance or preventative strategies. This study explored the feelings of women who learned about their hereditary risk only after their diagnosis younger than 52 years and who eventually tested positive for a BRCA gene mutation. METHODS: Thirty-four such women were mailed an invitation to participate in this research including a letter of information, consent form, and discussion prompts for their written narrative response. Rigorous mixed method analyses were performed using Charmaz-based qualitative analyses as well as quantitative analyses. RESULTS: Thirteen women (38.2%) responded with narratives for qualitative analysis from which 4 themes were coconstructed as follows: I, types of emotions; II, emotional response; III, coping with emotions; and IV, advice to women at similar risk. Women felt they should have learned about their hereditary risk from their family physician and through public education before their diagnosis. Although not experienced at the time of diagnosis, anger, frustration, and regret were experienced after receiving their BRCA results. These emotions arose from our research participants' lack of opportunity for prior genetic counseling and testing opportunity for genetic counseling and testing. CONCLUSIONS: With increased public and physician education, it is hoped that women with significant family histories of breast/ovarian cancer will be identified before diagnosis and given options regarding cancer surveillance and risk reduction strategies.

Nematodes infect, but do not manipulate digging by, sand crabs, Lepidopa benedicti.

We examined sand crabs (Lepidopa benedicti) for endoparasites, and found the only parasite consistently infecting the studied population were small nematodes. Because many nematodes have complex life cycles involving multiple hosts, often strongly manipulating their hosts, we hypothesized that nematodes alter the behavior of their sand crab hosts. We predicted that more heavily infected crabs would spend more time above sand than less heavily infected crabs. Our data indicate infection by nematodes was not correlated with duration of time crabs spent above sand. We also suggest that organisms living in sandy beaches may benefit from relatively low parasite loads due to the low diversity of species in the habitat.

Cadmium (Cd(2+)) removal by nano zerovalent iron: surface analysis, effects of solution chemistry and surface complexation modeling.

Nano zerovalent iron (nZVI) is an effective remediant for removing various organic and inorganic pollutants from contaminated water sources. Batch experiments were conducted to characterize the nZVI surface and to investigate the effects of various solution properties such as pH, initial cadmium concentration, sorbent dosage, ionic strength, and competitive ions on cadmium removal by nZVI. Energy-dispersive X-ray and X-ray photoelectron spectroscopy results confirmed removal of Cd(2+) ions by nZVI through adsorption. Cd(2+) adsorption decreased in the presence of competitive cations in the order: Zn(2+) > Co(2+) > Mg(2+) > Mn(2+) = Cu(2+) > Ca(2+) > Na(2+) = K(+). Higher concentrations of Cl(-) significantly decreased the adsorption. Cadmium removal increased with solution pH and reached a maximum at pH 8.0. The effects of various solution properties indicated Cd(2+) adsorption on nZVI to be a chemisorption (inner-sphere complexation) process. The three surface complexation models (diffuse layer model, constant capacitance model, and triple layer model) fitted well to the adsorption edge experimental data indicating the formation of nZVI-Cd bidentate inner-sphere surface complexes. Our results suggest that nZVI can be effectively used for the removal of cadmium from contaminated water sources with varying chemical conditions.

Kinetics and thermodynamics of cadmium ion removal by adsorption onto nano zerovalent iron particles.

Nano zerovalent iron (nZVI) is an effective adsorbent for removing various organic and inorganic contaminants. In this study, nZVI particles were used to investigate the removal of Cd(2+) in the concentration range of 25-450 mg L(-1). The effect of temperature on kinetics and equilibrium of cadmium sorption on nZVI particles was thoroughly examined. Consistent with an endothermic reaction, an increase in the temperature resulted in increasing cadmium adsorption rate. The adsorption kinetics well fitted using a pseudo second-order kinetic model. The calculated activation energy for adsorption was 54.8 kJ mol(-1), indicating the adsorption process to be chemisorption. The intraparticle diffusion model described that the intraparticle diffusion was not the only rate-limiting step. The adsorption isotherm data could be well described by the Langmuir as well as Temkin equations. The maximum adsorption capacity of nZVI for Cd(2+) was found to be 769.2 mg g(-1) at 297 K. Thermodynamic parameters (i.e., change in the free energy (ΔG(o)), the enthalpy (ΔH(o)), and the entropy (ΔS(o))) were also evaluated. The overall adsorption process was endothermic and spontaneous in nature. EDX analysis indicated the presence of cadmium ions on the nZVI surface. These results suggest that nZVI could be employed as an efficient adsorbent for the removal of cadmium from contaminated water sources.