Viable Load Research Articles

Quantifying quanta: Determining emission rates from clinical data

It is important to quantify uncertainty in the viable genomic material encapsulated in the respiratory particles emitted by infected people so that it can be converted into an emission rate as a function of respiratory and metabolic activities and used to estimate the probability of infection for an indoor scenario. Clinical measurements of viral loads for SARS-CoV-2 made using infection surveys, Gesundheit-II samplers, and human challenge studies are evaluated and a mathematical model is derived to estimate the quantum emission rate as a function of the genomic and viable viral loads. Modelled emission rates for SARS-CoV-2 agree with clinical data above detection limits. The viral load is found to vary over at least 6 orders of magnitude because it is person and time dependent, and contingent on many other factors that are difficult to quantify. It is similarly large for other respiratory pathogens. Therefore, the genomic and viable-virion emission rates display similar heterogeneity. When emission rates are used to estimate absolute infection risk using the Wells-Riley model, the predictions are so uncertain that they cannot be used in any meaningful way to provide useful quantitative guidance for designing indoor spaces.

Anti-Candida activity and biocompatibility of silver nanoparticles associated with denture glaze: a new approach to the management of denture stomatitis.

The association of silver nanoparticles (AgNps) to sealant agent Palaseal® can be a promising alternative for complete denture wearers who may develop denture stomatitis (DS). The study aimed to evaluate the anti-Candida and biocompatible potential of silver nanoparticles synthesized by three routes associated with denture glaze to prevent and/or treat oral candidiasis. Surface acrylic resin specimens were treated with different associations of glaze with AgNps (VER+AgUV, VER+AgTurk and VER+AgGm). As controls, specimens were treated with glaze+nystatin (VER+Nyst), glaze only (VER) or submerged in PBS (PBS). Afterwards, Candida albicans biofilm was developed for 24h, 15 d and 30 d. Subsequently, the biofilm was quantified by CFU/mL, XTT assay and confocal laser scanning microscopy. Fibroblasts were submitted to conditioned medium with the same associations for 24, 48 and 72h and LIVE/DEAD® viability test was carried out. Regardless of the period, there was a significant reduction (p < 0.01) of viable fungal cells load, as well as inhibition of fungal metabolic activity, in specimens treated with glaze+AgNps associations, compared to VER and PBS. The anti-Candida effects of the associations were similar to the VER+Nyst group, with emphasis on VER+AgGm, which showed the highest percentage values of non-viable fungal cells maintained over time. The associations did not prove toxicity to fibroblasts. The AgNps exerted antimicrobial activity against C. albicans biofilms and are biocompatible. The most effective results were achieved with the association of glaze+silver nanoparticles synthesized by the green chemistry method (AgGm), proving to be an innovative alternative in the management of DS.

Structural behaviour of asymptotic geodesic hybrid timber gridshells

Asymptotic geodesic gridshells are a novel structural system that is fabricated from straight and flat planks. The planks are elastically bent and twisted around their slender dimension to achieve the desired geometry, while the tall dimension creates structural stiffness. This system combines the geometric features of asymptotic and geodesic curves to create a hybrid tri-hex network on doubly curved surfaces, and provides a stable grid to resist its self-weight and external loads. To comprehensively explore the structural capabilities of asymptotic geodesic gridshells, a full-scale timber gridshell prototype was designed and built. Loading tests, including local and one shell asymmetrical loading, were carried out to examine the structural behaviour of the gridshell. A nonlinear finite-element model was developed and subsequently validated using experimental data. The evaluation of the timber gridshell revealed its high performance under uniformly distributed loads, and the simulation indicated a viable live load capacity of 7.0 kN/m². In a parametric study, the influence of the polar array layout, the joint rotation stiffness, and the support condition on the structural performance of the hybrid gridshell are analysed. Parameters influencing the achievable span are discussed regarding strength, stiffness and buckling behaviour for future design considerations.

Effect of pineapple core powder on white finger millet vegan probiotic beverage: Nutrition, sensory and storage

The present study aims to develop, optimize, and evaluate the effective incorporation of pineapple core powder (PCP) in plant-based probiotic beverages using Lactocaseibacillus rhamnosus (LGG). The optimization was carried out using pH, viscosity, and LGG viable load as response variables in the d-optimal mixer design. In optimized products, the changes in pH, titratable acidity (TA), and LGG viable load are observed during fermentation and storage conditions. The optimum condition for developing PCP-added white finger millet probiotic beverage (PAMPB) was 14:5:2:2 for white finger millet, sugar, PCP, and LGG inoculums, respectively. A PAMPB provided a higher LGG viable load of 11.34 log (CFU/mL) within 6 h of fermentation time. The PCP effectively increases the physiochemical properties like total phenolic count (17.64 mg GAE/g), total antioxidant activity, total flavonoid count (8.59 mg QE/g), and water holding capacity (41.52 %) of the PAMPB. In addition, the different sugar profiles and new pineapple aroma compounds like ethyl hexanoate and methyl hexanoate are identified in PAMPB. During the storage of PAMPB at 4⁰C for 21 days, the reduction in LGG viable count was observed from 11.54 to 9.39 log (CFU/mL). Incorporating PCP in millet beverages provides a positive result by increasing nutritional quality.

Physicochemical, sugar profile, probiotic viability, and E-nose aroma profile of probiotic beverage enriched with pineapple pomace

The present study aims to develop, optimize, and evaluate the effective incorporation of pineapple pomace powder (PPP) in millet probiotic beverages. The Lactocaseibacillus rhamnosus (LGG) was used as a microbial culture for the fermentation process. Based on the PPP and LGG combination nine sample mixes were selected and optimized based on the response variables such as pH, titratable acidity (TA), probiotic LGG load, and viscosity using a D-optimal mixer design. The optimized condition for the development of PPP added millet probiotic beverage (PPB) was 14:5:3:1 (sample mix S33) of white finger millet (WFM), sugar, PPP, and LGG inoculums, respectively. The PPB provided a higher LGG viable load of 11.20 log (CFU/mL). The PPP effectively enhance the functional and physiochemical property of the probiotic beverage. The TPC was found to be 18.63 mg GAE/g of a sample, TFC of 7.24 mg QE/g of a sample, DPPH of 72.46%, and ABTS of 71.52%. The different sugar profiles and pineapple aroma compounds are identified in PPB, also they have a higher sensory score. During the storage of PPB at 4⁰C for 21 days, the reduction in LGG viable count was observed from 11.54 to 10.25 log (CFU/mL). These findings may be used to enhance the properties of millet probiotic beverages by adding PPP and usage of PPP as a prebiotic source in the beverages.

Comparison of peroxyacetic acid and acidified sodium chlorite at reducing natural microbial contamination on chicken meat pieces

The spin-chill process at poultry processing plants involves the immersion of chicken carcasses in cold water (<5°C) often containing sodium hypochlorite which significantly contributes to the reduction of bacterial loads. Cutting carcasses into pieces, however, has been linked with increases in Campylobacter and Salmonella counts. Here, the efficacy of PAA and ASC on reducing bacteria on skin-on, bone-in thigh cuts was investigated. Three concentrations of ASC (60, 112, and 225 ppm) and PAA (50, 75, 100 ppm) were used. Thighs were dipped into sanitizer and tested for total viable bacterial counts, Campylobacter load, and prevalence of Salmonella. The efficacy of PAA and ASC was also compared with chlorine (8 ppm). All sanitizers exhibited a greater log reduction compared with water. PAA at both 75 and 100 ppm resulted in significantly higher log reductions compared with the water only. PAA at 100 ppm and 225 ppm ASC were the most effective at reducing Campylobacter. All wash treatments reduced the proportion of Salmonella positive samples, but the greatest reduction was observed for 225 ppm ASC. Both concentrations of ASC resulted in a greater reduction in total viable counts compared with chlorine.

Unlocking environmental contamination of animal tuberculosis hotspots with viable mycobacteria at the intersection of flow cytometry, PCR, and ecological modelling

Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex (MTBC), circulates in multi-host mammal communities. While interactions between different host species are mainly indirect, current knowledge postulates interspecific transmission is favored by animal contact with natural substrates contaminated with droplets and fluids from infected animals. However, methodological constraints have severely hampered monitoring of MTBC outside its hosts and the subsequent validation of this hypothesis.In this work, we aimed to evaluate the extent to which environmental contamination with M. bovis occurs in an endemic animal TB setting, taking advantage of a new real-time monitoring tool we recently developed to quantify the proportion of viable and dormant MTBC cell fractions in environmental matrices. Sixty-five natural substrates were collected nearby the International Tagus Natural Park region, in the epidemiological TB risk area in Portugal. These included sediments, sludge, water, and food deployed at unfenced feeding stations. The tripartite workflow included detection, quantification, and sorting of different M. bovis cell populations: total, viable, and dormant. Real-time PCR targeting IS6110 to detect MTBC DNA was performed in parallel. The majority of samples (54 %) contained metabolically active or dormant MTBC cells. Sludge samples had a higher burden of total MTBC cells and a high concentration of viable cells (2.3 × 104 cells/g). Ecological modelling informed by climate, land use, livestock and human disturbance data suggested eucalyptus forest and pasture cover as potential major factors affecting the occurrence of viable MTBC cells in natural matrices.Our study demonstrates, for the first time, the widespread environmental contamination of animal TB hotspots with viable MTBC bacteria and with dormant MTBC cells that are able to recover metabolic activity. Further, we show that viable MTBC cell load in natural substrates is superior to the estimated minimum infective dose, providing real-time insights into the potential magnitude of environmental contamination for indirect TB transmission.

Attempts to limit sporulation in the probiotic strain Bacillus subtilis BG01-4TM through mutation accumulation and selection.

The use of bacterial spores in probiotics over viable loads of bacteria has many advantages, including the durability of spores, which allows spore-based probiotics to effectively traverse the various biochemical barriers present in the gastrointestinal tract. However, the majority of spore-based probiotics developed currently aim to treat adults, and there is a litany of differences between the adult and infant intestinal systems, including the immaturity and low microbial species diversity observed within the intestines of infants. These differences are only further exacerbated in premature infants with necrotizing enterocolitis (NEC) and indicates that what may be appropriate for an adult or even a healthy full-term infant may not be suited for an unhealthy premature infant. Complications from using spore-based probiotics for premature infants with NEC may involve the spores remaining dormant and adhering to the intestinal epithelia, the out-competing of commensal bacteria by spores, and most importantly the innate antibiotic resistance of spores. Also, the ability of Bacillus subtilis to produce spores under duress may result in less B. subtilis perishing within the intestines and releasing membrane branched-chain fatty acids. The isolate B. subtilis BG01-4TM is a proprietary strain developed by Vernx Biotechnology through accumulating mutations within the BG01-4TM genome in a serial batch culture. Strain BG01-4TM was provided as a non-spore-forming B. subtilis , but a positive sporulation status for BG01-4TM was confirmed through in vitro testing and suggested that selection for the sporulation defective genes could occur within an environment that would select against sporulation. The durability of key sporulation genes was ratified in this study, as the ability of BG01-4TM to produce spores was not eliminated by the attempts to select against sporulation genes in BG01-4TM by the epigenetic factors of high glucose and low pH. However, a variation in the genes in isolate BG01-4-8 involved in the regulation of sporulation is believed to have occurred during the mutation selection from the parent strain BG01-4TM. An alteration in selected sporulation regulation genes is expected to have occurred from BG01-4TM to BG01-4-8, with BG01-4-8 producing spores within 24 h, ~48 h quicker than BG01-4TM.

In vivo effect of mouthwashes on viable viral load of SARS-CoV-2 in saliva: a pilot study

ABSTRACT Current data on the efficacy of antiseptic mouthwashes to reduce viral load are contradictory. Firstly, in vitro data indicate very strong virucidal effects that are not replicated in clinical studies. Secondly, most clinical studies identify a limited effect, do not include a control/placebo group, or do not evaluate viral viability in an infection model. In the current manuscript, we perform a double-blind, randomized clinical trial where salivary viral load was measured before and after the mouthwash, and where saliva samples were also cultured in an in vitro infection model of SARS-CoV-2 to evaluate the effect of mouthwashes on viral viability. Our data show a 90–99% reduction in SARS-CoV-2 salivary copies with one of the tested mouthwashes, although we show that the remaining viruses are mostly viable. In addition, our data suggest that the active ingredient concentration and the overall excipients’ formulation can play an important role; and most importantly, they indicate that the effect is not immediate, being significant at 15 min and having maximum effectiveness after 1 h. Thus, we show that some oral mouthwashes can be useful in reducing viral transmission, although their efficacy must be improved through refined formulations or revised protocols.

Spatial optimization of nutrient recovery from dairy farms to support economically viable load reductions in the Chesapeake Bay Watershed

Spatial optimization of nutrient recovery from dairy farms to support economically viable load reductions in the Chesapeake Bay Watershed

A REVIEW OF CURRENT KNOWLEDGE ON AIRBORNE TRANSMISSION OF COVID-19 AND THEIR RELATIONSHIP WITH ENVIRONMENT

Background: SARS-CoV-2 is considered the critical health pandemic of 21st century. Due to their extremely high rate of transmission people are more susceptible to viral infection. The airborne transmission considered to be the dominant over other route of transmissions. Viral RNA affiliated with droplets smaller than 5 micro meters has been detected in air and the virus has been shown to preserve infectivity in droplets of this size. Mechanism: The modes of transmissions of virus is through direct contact and through inhaling aerosols. Transmission of SARS-CoV 2 could be directed not only by temperature and humidity but also by water and sewage, among other perspective factors. Airborne or aerosol transmission occurs by the direct spray of large droplets onto conjunctiva or mucous membranes. The optimum temperature and humidity for the survival of SARS-CoV-2 in vitro were 4 degree Celsius and 20-80% resp. 1-10 um aerosol particles are sufficiently large to carry a viable viral particle load. Under optimal conditions of humidity &amp; temperature, the aerosol droplets of all sizes can travel up to 7-8 m. As the size of aerosol decrease, their ability to disperse in air increase. Discussion: . The effect of transmission or spreadness of this virus is in a very sudden manner. The review of few studies shows that the behavior or mode of action of SARS-CoV-2 virus has been remarkable or unique with more survival rate and viable rates in the air and believed to remain in the air for extended period. This study is exploratory in nature and aims to carry out the nature of transmission of virus as a airborne transmission and their relationship with the environment.

Developing Stable Freeze-Dried Functional Ingredients Containing Wild-Type Presumptive Probiotic Strains for Food Systems

Designing stable dried functional food ingredients and foods containing live probiotic cultures maintaining high viable cell loads at the time of consumption is a challenge for the industry. The aim of the present study was the development of stable freeze-dried functional food ingredients with enhanced shelf-life during long storage. Zea flakes, pistachios, and raisins were used as immobilization supports for the wild-type presumptive probiotic strains Pediococcus acidilactici SK and Lactiplantibacillus plantarum F4, while L. plantarum B282 was used as a reference strain. Cell survival was monitored during storage at room and refrigerated temperatures for up to 6 months. Levels of freeze-dried cultures were maintained up to 7.2 logcfu/g after 6 months storage at room temperature and up to 8.5 logcfu/g at refrigerator temperature, in contrast to free cell levels that ranged &lt;7 logcfu/mL, suggesting the positive effects of immobilization and freeze-drying on cell viability. Of note, levels of freeze-dried immobilized P. acidilactici SK cells on zea flakes and pistachios remained stable after 6 months of storage at 4 °C, ranging 8.1–8.5 logcfu/g (survival rates 98.2 and 99.7%, respectively). The technology developed presents important advantages for the maintenance of cell viability during storage, assuring stability of ready-to-use functional food ingredients that could be directly incorporated in food systems.

Monitoring monkeypox virus in saliva and air samples in Spain: a cross-sectional study

The transmission of monkeypox virus occurs through direct contact, but transmission through saliva or exhaled droplets and aerosols has not yet been investigated. We aimed to assess the presence of monkeypox virus DNA and infectious virus in saliva samples and droplets and aerosols exhaled from patients infected with monkeypox virus. We did a cross-sectional study in patients with monkeypox confirmed by PCR who attended two health centres in Madrid, Spain. For each patient, we collected samples of saliva, exhaled droplets within a mask, and aerosols captured by air filtration through newly developed nanofiber filters. We evaluated the presence of monkeypox virus in the samples by viral DNA detection by quantitative PCR (qPCR) and isolation of infectious viruses in cell cultures. Between May 18 and July 15, 2022, 44 patients with symptomatic monkeypox attended two health centres in Madrid and were included in the study. All were cisgender men, with a median age of 35·0 years (IQR 11·3). We identified high loads of monkeypox virus DNA by qPCR in 35 (85%) of 41 saliva samples. Infectious monkeypox virus was recovered from 22 (67%) of 33 saliva samples positive for monkeypox virus DNA. We also found a significant association between the number of affected cutaneous areas or general symptoms and the viral load present in saliva samples. Droplets exhaled from patients with monkeypox, detected inside a mask, contained monkeypox virus DNA in 32 (71%) of 45 samples, with two of the 32 positive samples showing the presence of the infectious virus. Monkeypox virus DNA in aerosols, collected from the medical consultation room, were detected in 27 (64%) of 42 samples, despite patients wearing an FFP2 mask during the visit. Infectious virus was not recovered from aerosol samples. High levels of monkeypox virus DNA were identified in aerosols collected from a hospital isolation room housing a patient with monkeypox. The identification of high viable monkeypox virus loads in saliva in most patients with monkeypox and the finding of monkeypox virus DNA in droplets and aerosols warrants further epidemiological studies to evaluate the potential relevance of the respiratory route of infection in the 2022 monkeypox virus outbreak. EU, Consejo Superior de Investigaciones Científicas, and Ciberinfec.

Medically important bacteria isolated from commercial herbal medicines in Kampala city indicate the need to enhance safety frameworks

The high global bacterial infection burden has created need to investigate the neglected potential drivers of pathogenic bacteria, to inform disease prevention. Kampala is facing a proliferation of herbalists, selling herbal medicine (HM), of largely unregulated microbiological quality. We evaluated the bacterial contamination burden in HM sold in Kampala, to support evidence-based redress. The total viable loads (TVL), total coliform counts (TCC), E. coli counts, and prevalence of selected bacterial strains in 140 HM were examined using conventional culture, following the guidelines of World Health Organization (WHO), and Uganda National Drug Authority (NDA). Data were analyzed using D'Agostino-Pearson test, frequencies, proportions, Chi-square, and Mann–Whitney U test with STATA version-15.0. Fifty (35.7%), fifty-nine (42.1%), and twelve (8.6%) HM were unsafe for human use because they exceeded WHO’s permissible limits for TVL, TCC, and E. coli counts respectively. Solids had significantly higher mean TVL than liquids. Violation of NDA’s guidelines was significantly associated with high TVL. Fifty-nine bacteria, viz., Klebsiella pneumoniae (n = 34; 57.6%), Escherichia. coli (12; 20.3%), Staphylococcus aureus (7; 11.9%), Klebsiella oxytoca (3; 5.1%), Bacillus cereus, Pseudomonas aeruginosa, and Enterobacter spp. (1; 1.7% each), were isolated from 45 (32.1%) samples. These bacteria can cause severe clinical diseases, and promote deterioration of HM potency.

Synthesis and Evaluation of a Silver Nanoparticle/Polyurethane Composite That Exhibits Antiviral Activity against SARS-CoV-2.

In this proof-of-concept study, we aim to produce a polyurethane (PU)-based composite that can reduce the amount of viable SARS-CoV-2 virus in contact with the surface of the polymeric film without further interventions such as manual cleaning. Current protocols for maintaining the hygiene of commonly used touchpoints (door handles, light switches, shop counters) typically rely on repeated washing with antimicrobial products. Since the start of the SARS-CoV-2 pandemic, frequent and costly surface sanitization by workers has become standard procedure in many public areas. Therefore, materials that can be retrofitted to touchpoints, yet inhibit pathogen growth for extended time periods are an important target. Herein, we design and synthesise the PU using a one-pot synthetic procedure on a multigram scale from commercial starting materials. The PU forms a robust composite thin film when loaded with 10 wt% silver nanoparticles (AgNPs). The addition of AgNPs increases the ultimate tensile strength, modules of toughness and modulus of elasticity at the cost of a reduced elongation at break when compared to the pristine PU. Comparative biological testing was carried out by the addition of pseudotyped virus (PV) bearing the SARS-CoV-2 beta (B.1.351) VOC spike protein onto the film surfaces of either the pristine PU or the PU nanocomposite. After 24 h without further human intervention the nanocomposite reduced the amount of viable virus by 67% (p = 0.0012) compared to the pristine PU treated under the same conditions. The significance of this reduction in viable virus load caused by our nanocomposite is that PUs form the basis of many commercial paints and coatings. Therefore, we envisage that this work will provide the basis for further progress towards producing a retrofittable surface that can be applied to a wide variety of common touchpoints.

Monitoring autochthonous lung tumors induced by somatic CRISPR gene editing in mice using a secreted luciferase

BackgroundIn vivo gene editing of somatic cells with CRISPR nucleases has facilitated the generation of autochthonous mouse tumors, which are initiated by genetic alterations relevant to the human disease and progress along a natural timeline as in patients. However, the long and variable, orthotopic tumor growth in inner organs requires sophisticated, time-consuming and resource-intensive imaging for longitudinal disease monitoring and impedes the use of autochthonous tumor models for preclinical studies.MethodsTo facilitate a more widespread use, we have generated a reporter mouse that expresses a Cre-inducible luciferase from Gaussia princeps (GLuc), which is secreted by cells in an energy-consuming process and can be measured quantitatively in the blood as a marker for the viable tumor load. In addition, we have developed a flexible, complementary toolkit to rapidly assemble recombinant adenoviruses (AVs) for delivering Cre recombinase together with CRISPR nucleases targeting cancer driver genes.ResultsWe demonstrate that intratracheal infection of GLuc reporter mice with CRISPR-AVs efficiently induces lung tumors driven by mutations in the targeted cancer genes and simultaneously activates the GLuc transgene, resulting in GLuc secretion into the blood by the growing tumor. GLuc blood levels are easily and robustly quantified in small-volume blood samples with inexpensive equipment, enable tumor detection already several months before the humane study endpoint and precisely mirror the kinetics of tumor development specified by the inducing gene combination.ConclusionsOur study establishes blood-based GLuc monitoring as an inexpensive, rapid, high-throughput and animal-friendly method to longitudinally monitor autochthonous tumor growth in preclinical studies.

A PMAxxTM qPCR Assay Reveals That Dietary Administration of the Microalgae Tetraselmis chuii Does Not Affect Salmonella Infantis Caecal Content in Early-Treated Broiler Chickens.

Simple SummarySalmonella enterica subsp. enterica serovar Infantis (S. Infantis) has emerged as a relevant serovar commonly reported in poultry products, which represents a potential public threat. Microalgae synthesize molecules that exert positive effects both on chicken performance and health. Tetraselmis chuii produces fermentable polysaccharides capable of influencing caecal diversity. We tested if the administration of T. chuii could alter caecal microbiota in favor of a reduced S. Infantis load. Animals were fed a microalgae-based diet and challenged with bacteria on day 4. Two days after infection, caecal samples were taken and the viable load of S. Infantis was estimated utilizing a PMAxxTM-based qPCR method, which was developed and tested for assessing the differences between groups. Dietary inclusion of the chlorophyte did not alter bacterial viable load; however, the method proved to be efficient, sensitive, and repeatable. Certainly, the approach used herein could be applied in studies evaluating the effects of different treatments on Salmonella caecal colonization.Salmonella enterica serovars cause infections in humans. S. enterica subsp. enterica serovar Infantis is considered relevant and is commonly reported in poultry products. Evaluating innovative approaches for resisting colonization in animals could contribute to the goal of reducing potential human infections. Microalgae represent a source of molecules associated with performance and health improvement in chickens. Tetraselmis chuii synthesizes fermentable polysaccharides as part of their cell wall content; these sugars are known for influencing caecal bacterial diversity. We hypothesized if its dietary administration could exert a positive effect on caecal microbiota in favor of a reduced S. Infantis load. A total of 72 one-day-old broiler chickens (COBB 500) were randomly allocated into three groups: a control, a group infected with bacteria (day 4), and a group challenged with S. Infantis but fed a microalgae-based diet. Caecal samples (n = 8) were collected two days post-infection. A PMAxxTM-based qPCR approach was developed to assess differences regarding bacterial viable load between groups. The inclusion of the microalga did not modify S. Infantis content, although the assay proved to be efficient, sensitive, and repeatable. The utilized scheme could serve as a foundation for developing novel PCR-based methodologies for estimating Salmonella colonization.

Pandemic Preparedness and Response: A Foldable Tent to Safely Remove Contaminated Dental Aerosols—Clinical Study and Patient Experience

The D-DART (Droplet and Aerosol Reducing Tent) is a foldable design that can be attached to the dental chair to prevent the spread of contaminated dental aerosols. The objective of this study was to evaluate the ability of the D-DART to reduce spread of aerosols generated during dental treatment. Thirty-two patients (sixteen per group) undergoing deep ultrasonic scaling were recruited and randomly allocated to groups D-DART or Control (no D-DART). After 20 min from the start of the treatment, the clinician’s face shield and dental chair light were swabbed and the viable microbial load was quantified (ATP bioluminescence analysis, blinded operator). Statistical analyses were performed with Tukey’s Honest Test with a level of significance pre-set at 5%. There were significant increases in ATP values obtained from the operator’s face shield and dental chair light for the Control compared with baseline (31.3 ± 8.5 and fold increase). There was no significant change in microbial load when the D-DART was used compared with baseline (1.5 ± 0.4 fold increase). The D-DART contained and prevented the spread of aerosols generated during deep scaling procedures.

Investigation of Bacterial Load and Their Antimicrobial Susceptibility in an Artisanal Refining Environment

Background: Bacteria present in the atmosphere often show predicable patterns across space and time. and these patterns and properties of the bacteria can be affected by presence of soot which is generated by artisanal refining and excessive burning of fossil fuel. These bacteria are being inhaled by humans on daily basis and this can have detrimental effects on human health and the environment.&#x0D; Aim: This work was carried out to investigate the microbial load and antimicrobial susceptibility of an environment associated with artisanal refining activities.&#x0D; Methodology: The eight samples were taken randomly from four different locations in a high artisanal refining state Rivers State (Ojoto Roundabout, Nembe Waterside, Rumuokalagbor Village, Rivers State University Teaching Hospital (RSUTH), Rivers State University Microbiology laboratory and Mile 1 Park) all in Port Harcourt, Rivers State and compared to two locations from another state Kano state (No. 33 Lamido Crescent and God is Good Motors Park, Kano State) without artisanal refining activities all in Nigeria and tested for viable bacteria load. The six test and two control samples were collected on prepared dry nutrient agar exposed to free air for a period of five (5) minutes and were covered properly and transferred to the laboratory and incubated at 37OC for 24 hours. The isolates were morphologically and biochemically determined and identified.&#x0D; Results: The Total Heterotrophic count indicates that samples from Rumuokalagbor village have a high number of bacteria growth colonies with a colony forming unit of 1.43 x 106 while sample from Rivers State University Teaching Hospital had lesser colony forming unit of 7.5 x 105,. However, the Total Heterotrophic Bacteria Count from our control is seen to be very low with 3.2 x 105 and 2.8 x 105 respectively. Microorganisms such as Staphylococcus aureus, Bacillus species and Staphylococcus species. were identified from the various locations. Few isolates were gotten from the entire laboratory with a total of 22 isolates, 18 Bacillus species (77), 3 Staphylococcus species (18%) and 1 Staphylococcus aureus (5%). The antimicrobial sensitivity results revealed Ciprofloxacin (77%) having higher sensitivity followed by Levofloxacin (66.6%). Norfloxacin (0%), Rifampicin (0%) and Ampiclox (0%) were seen to be highly resistant to the bacteria isolated.&#x0D; Conclusion: This work was able to identify Bacillus species,Staphylococcus species and Staphylococcus aerues. as bacteria associated with artisanal refining at the different sampled sites. Strict implementation on stopping artisanal refining in our communities is recommended to reduce the public health risk posed by soot inhalation.

Introducing seasonal snow memory into the RUSLE

PurposeThe sediment supply to rivers, lakes, and reservoirs has a great influence on hydro-morphological processes. For instance, long-term predictions of bathymetric change for modeling climate change scenarios require an objective calculation procedure of sediment load as a function of catchment characteristics and hydro-climatic parameters. Thus, the overarching objective of this study is to develop viable and objective sediment load assessment methods in data-sparse regions.MethodsThis study uses the Revised Universal Soil Loss Equation (RUSLE) and the SEdiment Delivery Distributed (SEDD) model to predict soil erosion and sediment transport in data-sparse catchments. The novel algorithmic methods build on free datasets, such as satellite and reanalysis data. Novelty stems from the usage of freely available datasets and the introduction of a seasonal snow memory into the RUSLE. In particular, the methods account for non-erosive snowfall, its accumulation over months as a function of temperature, and erosive snowmelt months after the snow fell.ResultsModel accuracy parameters in the form of Pearson’s r and Nash–Sutcliffe efficiency indicate that data interpolation with climate reanalysis and satellite imagery enables viable sediment load predictions in data-sparse regions. The accuracy of the model chain further improves when snow memory is added to the RUSLE. Non-erosivity of snowfall makes the most significant increase in model accuracy.ConclusionThe novel snow memory methods represent a major improvement for estimating suspended sediment loads with the empirical RUSLE. Thus, the influence of snow processes on soil erosion and sediment load should be considered in any analysis of mountainous catchments.