Microbial Density Research Articles

A Critical Review of Risk Assessment Models for Listeria monocytogenes in Meat and Meat Products.

A review of the published quantitative risk assessment (QRA) models of L. monocytogenes in meat and meat products was performed, with the objective of appraising the intervention strategies deemed suitable for implementation along the food chain as well as their relative effectiveness. A systematic review retrieved 23 QRA models; most of them (87%) focused on ready-to-eat meat products and the majority (78%) also covered short supply chains (end processing/retail to consumption, or consumption only). The processing-to-table scope was the choice of models for processed meats such as chorizo, bulk-cooked meat, fermented sausage and dry-cured pork, in which the effects of processing were simulated. Sensitivity analysis demonstrated the importance of obtaining accurate estimates for lag time, growth rate and maximum microbial density, in particular when affected by growth inhibitors and lactic acid bacteria. In the case of deli meats, QRA models showed that delicatessen meats sliced at retail were associated with a higher risk of listeriosis than manufacture pre-packed deli meats. Many models converged on the fact that (1) controlling cold storage temperature led to greater reductions in the final risk than decreasing the time to consumption and, furthermore, that (2) lower numbers and less prevalence of L. monocytogenes at the end of processing were far more effective than keeping low temperatures and/or short times during retail and/or home storage. Therefore, future listeriosis QRA models for meat products should encompass a processing module in order to assess the intervention strategies that lead to lower numbers and prevalence, such as the use of bio-preservation and novel technologies. Future models should be built upon accurate microbial kinetic parameters, and should realistically represent cross-contamination events along the food chain.

Biotrapping Ureolytic Bacteria on Sand to Improve the Efficiency of Biocementation.

Microbially induced calcium carbonate precipitation (MICP) has emerged as a novel technology with the potential to produce building materials through lower-temperature processes. The formation of calcium carbonate bridges in MICP allows the biocementation of aggregate particles to produce biobricks. Current approaches require several pulses of microbes and mineralization media to increase the quantity of calcium carbonate minerals and improve the strength of the material, thus leading to a reduction in sustainability. One potential technique to improve the efficiency of strength development involves trapping the bacteria on the aggregate surfaces using silane coupling agents such as positively charged 3-aminopropyl-methyl-diethoxysilane (APMDES). This treatment traps bacteria on sand through electrostatic interactions that attract negatively charged walls of bacteria to positively charged amine groups. The APMDES treatment promoted an abundant and immediate association of bacteria with sand, increasing the spatial density of ureolytic microbes on sand and promoting efficient initial calcium carbonate precipitation. Though microbial viability was compromised by treatment, urea hydrolysis was minimally affected. Strength was gained much more rapidly for the APMDES-treated sand than for the untreated sand. Three injections of bacteria and biomineralization media using APMDES-treated sand led to the same strength gain as seven injections using untreated sand. The higher strength with APMDES treatment was not explained by increased calcium carbonate accrual in the structure and may be influenced by additional factors such as differences in the microstructure of calcium carbonate bridges between sand particles. Overall, incorporating pretreatment methods, such as amine silane coupling agents, opens a new avenue in biomineralization research by producing materials with an improved efficiency and sustainability.

Effect of nira (Arenga pinnata Merr) tapping tools on the abudance and identification of microorganisms

Arenga trees are known to have economic value, especially its water, called nira. Nira contains sucrose with a neutral pH at the start of tapping, but after 4 hours, the quality of nira will decrease. This is due to the influence of air (aerobic), so that the presence of microbes in nira becomes abundant and causes the fermentation process to take place more quickly. The fermented nira is known as ‘tuak’, the traditional drink of Bataknese people. Batak people believe the benefits of drinking tuak for health. In this study, nira was collected using a simple tapping device (APUS) with the aim of minimizing contact between surrounding air and bunches. APUS was applied to Arenga bunches in Samosir. Nira from tapping with and without APUS will be observed for microbial abundance (its density). Furthermore, the microbes contained in nira will be identified based on their morphological characters (physically). Identification aims to determine the types of microbes that are present from a natural habitat. Next, the microbes are isolated and studied for their shape and properties, before the microbes are utilized further. The results of microscopic observations showed that the nira sample tapped without using APUS (sample A) had a higher and more turbid microbial density and showed non-uniform microbial size (from large to small, like powder), while nira sample tapped with APUS (sample B) showed almost uniform microbial size with cleaner looking spots. Furthermore, the microbes in sample B were isolated on specific media. Acquisition of colonies in the form of acetic acid bacteria (BAA), lactic acid bacteria (BAL), and yeast. BAA isolates showed a group of gram-negative bacteria that could not retain the crystal violet stain when rinsed with alcohol, because the peptidoglycan in gram-negative bacteria was thinner than gram-positive ones, while BAL isolates were the opposite. The measurement of the number of colonies was carried out using the TPC (Total Plate Count) method at 6 dilutions and obtained for BAL and yeast were 147 and 30 colonies respectively.

Study of the influence of nanoscale porosity on the microbial electroactivity between expanded graphite electrodes and Geobacter sulfurreducens biofilms.

Expanded graphite (EG) electrodes gather several advantages for their utilization in microbial electrochemical technologies (MET). Unfortunately, the low microbial electroactivity makes them non-practical for implementing them as electrodes. The objective of this work is to explore the enhancement of microbial electroactivity of expanded graphite (commercial PV15) through the generation of nanopores by CO2 treatment. The changes in properties were thoroughly analysed by TG, XRD, Raman, XPS, gas adsorption, SEM and AFM, as well as microbial electroactivity in the presence of Geobacter sulfurreducens. Nanopores remarkably enhance the microbially derived electrical current (60-fold increase). Given the inaccessibility of micron-sized bacteria to these nanopores, it is suggested that the electric charge exchanged by electroactive microorganisms might be greatly affected by the capability of the electrode to compensate these charges through ion adsorption. The increased microbial current density produced on activated PV15 opens the possibility of using such materials as promising electrodes in MET.

Composts Obtained by Mixing Hop Leaves with Wheat Straw or Farmyard Manure Improved Soil Properties and Increased Microbial Communities

Hop (Humulus lupulus L.) leaves are rich in nutrients, particularly nitrogen (N). After harvest, they can be recycled through composting for use as a soil amendment. In this study, we report the effect of composts obtained from mixtures of hop leaves with other organic materials (wheat straw, farmyard manure, and ash from hop stems) at different ratios on soil properties and microbial diversity. Data on total N, total organic carbon (TOC), microbial N (Mic-N), microbial C (Mic-C), soil basal respiration (SBR), metabolic quotient (qCO2), Mic-C/TOC ratio, acid phosphatase activity (APA), microbial density, and species identification were assessed after each one of the two growing seasons of potted lettuce (Lactuca sativa L.). The diversity of microbial species was evaluated using Simpson and Shannon diversity indexes, and the interactions between soil properties and the microbial community were explored. Higher microbial activity was found among the soils amended with leaves plus straw (HS), which exhibited higher levels of TOC, APA, Mic-N, and total N in the first growing cycle and higher levels of Mic-C, Mic-C/TOC, SBR, TOC, and Mic-N in the second growing cycle. Fungi identified belong to the Ascomycota and Zygomycota phyla, while bacteria belong to the Actinobacteria, Bacillota, Bacteroidetes, Firmicutes, and Proteobacteria phyla. Differences in the prevalent microbial genera were observed between compost treatments and growing cycles. Correlation analysis revealed significant relationship between soil bacteria and fungi abundance and higher levels of N and C in the soils, indicating the relevance of specific microbial genera, such Acrostalagmus, Doratomyces, Talaromyces, and Aspergillus fungi, as well as Gordonia and Bacillus bacteria. Overall, the results indicate that hop leaves-based compost, particularly with a higher proportion of leaves and straw, influenced the composition of the soil microbial community, ultimately enhancing soil N availability for plant development.

Effect of Mycorrhizae, Azotobacter and Vermicompost Tea on Nitrogen, Phosphorus, and Potassium (NPK) Concentrations in Soil and Cucumber Plants (Cucumis sativus)

An experiment was carried out inside a greenhouse (sandy loam soil) at the College of Agriculture / University of Anbar to investigate the effect of Vesicular-Arbuscular Mycorrhizaee, Azotobacterchroococcum and Vermicompost tea on the concentration of NPK macronutrients in soil and cucumber plants. A factorial experiment consisting of two factors was designed for this purpose: the first factor is a combination of mycorrhizae (M) with 35 g plant−1, azotobacter (A) bacteria 16 ml plant−1 with a microbial density of 2.2 x 109 cfu ml−1 and phosphate Rock (R) with 40 g plant−1, added with half of the mineral fertilizer recommendation each individually with its interactions, the second factor is the addition of three concentrations (0, 5, 10%) of vermicompost tea sprayed on the plant. The experiment was designed with a completely randomized block design (RCBD) with three replications. Cucumber seeds were planted on 15/9/2022 and service operations were conducted for the crop and the experiment continued until 15/12/2022. The result showed highest percentage of phosphorus in the leaves (PIL) (0.40%), the highest potassium in the leaves (KL) (1.95%), followed by the treatment of adding mycorrhizae with phosphate Rock and half the mineral recommendation (MR) with vermicompost tea at a concentration of 10%, then the treatment of adding mycorrhizae with azotobacter bacteria with half the mineral recommendation (AR) with 10% of vermicompost tea, then the treatment of mycorrhizae with phosphate Rock plus half the fertilizer recommendation (MR) with 10% of vermicompost tea, then the treatment of mycorrhizae with azotobacter plus half of the fertilizer recommendation (MA) with 10% of vermicombe tea.

Assessing the Impacts of Lead Corrosion Control on the Microbial Ecology and Abundance of Drinking-Water-Associated Pathogens in a Full-Scale Drinking Water Distribution System.

Increases in phosphate availability in drinking water distribution systems (DWDSs) from the use of phosphate-based corrosion control strategies may result in nutrient and microbial community composition shifts in the DWDS. This study assessed the year-long impacts of full-scale DWDS orthophosphate addition on both the microbial ecology and density of drinking-water-associated pathogens that infect the immunocompromised (DWPIs). Using 16S rRNA gene amplicon sequencing and droplet digital PCR, drinking water microbial community composition and DWPI density were examined. Microbial community composition analysis suggested significant compositional changes after the orthophosphate addition. Significant increases in total bacterial density were observed after orthophosphate addition, likely driven by a 2 log 10 increase in nontuberculous mycobacteria (NTM). Linear effect models confirmed the importance of phosphate addition with phosphorus concentration explaining 17% and 12% of the variance in NTM and L. pneumophila density, respectively. To elucidate the impact of phosphate on NTM aggregation, a comparison of planktonic and aggregate fractions of NTM cultures grown at varying phosphate concentrations was conducted. Aggregation assay results suggested that higher phosphate concentrations cause more disaggregation, and the interaction between phosphate and NTM is species specific. This work reveals new insight into the consequences of orthophosphate application on the DWDS microbiome and highlights the importance of proactively monitoring the DWDS for DWPIs.

Characterizing the Influence of a Heterotrophic Bicosoecid Flagellate Pseudobodo sp. on the Dinoflagellate Gambierdiscus balechii.

Microbial interactions including competition, mutualism, commensalism, parasitism, and predation, which can be triggered by nutrient acquisition and chemical communication, are universal phenomena in the marine ecosystem. The interactions may influence the microbial population density, metabolism, and even their environmental functions. Herein, we investigated the interaction between a heterotrophic bicosoecid flagellate, Pseudobodo sp. (Bicoecea), and a dinoflagellate, Gambierdiscus balechii (Dinophyceae), which is a well-known ciguatera food poisoning (CFP) culprit. The presence of Pseudobodo sp. inhibited the algal proliferation and decreased the cardiotoxicity of zebrafish in the algal extract exposure experiment. Moreover, a significant difference in microbiome abundance was observed in algal cultures with and without Pseudobodo sp. Chemical analysis targeting toxins was performed by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with molecular networking (MN), showing a significant alteration in the cellular production of gambierone analogs and some super-carbon chain compounds. Taken together, our results demonstrated the impact of heterotrophic flagellate on the photosynthetic dinoflagellates, revealing the complex dynamics of algal toxin production and the ecological relationships related to dinoflagellates in the marine environment.

PSI-8 Effect of Monensin Withdrawal on the Rumen Prokaryote Microbiome in Bos Indicus and Bos Taurus Steers Consuming Bermudagrass Hay

Abstract Monensin, a carboxylic polyether ionophore, is commonly added to ruminant diets as a strategy for improving animal production by altering ruminal fermentation. However, research concerning the effect of monensin withdrawal is limited. Therefore, the effect of monensin withdrawal and the subspecies of cattle on the rumen prokaryote microbiome was evaluated using ruminally cannulated steers (5 Bos indicus, BI and 5 Bos taurus, BT; 398 kg BW) consuming bermudagrass hay (13.7% CP). Subspecies were concurrently subjected to a two period, two treatment crossover design. Each 70-d period consisted of a 42 d adaptation phase with treatments including 0 (CON) or 200 (MON) mg·animal-1 monensin (Rumensin 90; Elanco Animal Health, Greenfield, IN) fed in 0.91 kg dried distillers grains with solubles daily. Withdrawal of monensin was then evaluated for a 28-d phase following adaptation. Rumen fluid was collected via suction strainer from the dorsal and ventral sacs of the rumen at feeding on d 1, 7, 14, 21, and 28 of the withdrawal phase and frozen until further analysis. Upon completion of the trial, samples were thawed and analyzed for microbial populations using massively parallel sequencing. The V4 region of the 16S rRNA gene was sequenced to analyze and compare rumen prokaryotic microbes within treatment groups and subspecies. Sequences were processed using QIIME 2 (q2) version 2021.2 and imported into R v4.1 for statistical analysis and graphical displays. Bray Curtis-based principle coordinate analysis (PCoA) provided visualization of microbial community clustering by monensin treatment and subspecies, facilitating identification of microbial community shifts resulting from treatments or subspecies. No monensin×subspecies×day interaction (P = 0.96) was observed. However, an effect of monensin (P = 0.01), subspecies (P ≤ 0.01), and day (P = 0.017) on the microbiome was present. The changes in microbial density that were observed with monensin withdrawal help to provide insight into the mode of action of monensin and its impact on potential methane mitigation in cattle.

Advantages of using a carbon-rich substrate in a constructed wetland for agricultural water treatment: Carbon availability and biota development

Proper bed substrate selection is essential for the growth of microorganisms and plants, which are key elements in constructed wetlands (CWs) performance. This is even more important in CWs that treat irrigated agricultural drainage water characterised by a high nitrogen (N), but low carbon (C) and phosphorus (P) concentration. This nutrient imbalance compromises biota activity and limits water treatment processes. Three substrates were tested in a CW field-scale pilot plant for 2 years: gravel (100%) and two mixed substrates, gravel + 30% natural wetland soil and gravel + 10% biochar. While gravel is one of the most commonly used substrates in subsurface flow CWs, soil has hardly been employed, and field-scale biochar application studies are scarce. We analysed the effect of adding a C-rich substrate to gravel on both nutrient imbalance correction and the biotic performance of CWs. Adding natural soil or biochar increased P availability in beds. However, the dissolved organic C concentration in interstitial water was only enhanced by soil addition. Unlike gravel, microbial density and activity, and Phragmites australis plant growth, were higher in beds with soil, followed by those with biochar. A similar pattern was observed for plant tissue quality. Although biochar proved positive for biota, it had a short-term effect as a source of C and P. Therefore, employing a suitable gravel-soil mixture provides notable advantages for the irrigated agricultural water treatment challenge. Even after considering some limitations, our results represent an important step to design CWs that treat this wastewater type and for eutrophication control in sustainable agroecosystems.

Effect of Mycorrhizae, Azotobacter and Vermicompost tea on Nitrogen, Phosphorus, and Potassium (NPK) Concentrations in Soil and Cucumber Plants (Cucumis sativus)

An experiment was carried out inside a greenhouse (sandy loam soil) at the College of Agriculture / University of Anbar to investigate the effect of Vesicular-Arbuscular Mycorrhizaee, Azotobacterchroococcum and Vermicompost tea on the concentration of NPK macronutrients in soil and cucumber plants. A factorial experiment consisting of two factors was designed for this purpose: the first factor is a combination of mycorrhizae (M) with 35 g plant-1, azotobacter (A) bacteria 16 ml plant-1 with a microbial density of 2.2 x 109 cfu ml-1 and phosphate Rock (R) with 40 g plant-1, added with half of the mineral fertilizer recommendation each individually with its interactions, The second factor is the addition of three concentrations (0, 5, 10%) of vermicompost tea sprayed on the plant. The experiment was designed with a completely randomized block design (RCBD) with three replications. Cucumber seeds were planted on 15/9/2022 and service operations were conducted for the crop and the experiment continued until 15/12/2022. Concentrations of nutrients were measured in the soil after harvesting the crop as well as in the leaves of the plant. The results of the research proved that the use of mycorrhizae, azotobacter bacteria and phosphate Rock with half the mineral recommendation (MAR) and spraying vermicompost tea at a concentration of 10% are the best in increasing the concentration of nutrients in the soil and plant and revealed significant differences compared to mycorrhizae or azotobacter or vermicompost tea individually, so this treatment gave the highest concentration of available nitrogen (AN) (56.37 mg kg-1 soil), the highest available phosphorus (AP) (16.34 mg kg-1 soil), the highest available potassium (230.3 mg kg-1 soil), and gave the highest percentage of nitrogen in the leaves (NIL) (2.80%), The highest percentage of phosphorus in the leaves (PIL) (0.40%), the highest potassium in the leaves (KL) (1.95%), followed by the treatment of adding mycorrhizae with phosphate Rock and half the mineral recommendation (MR) with vermicompost tea at a concentration of 10%, then the treatment of adding mycorrhizae with azotobacter bacteria with half the mineral recommendation (AR) with 10% of vermicompost tea, then the treatment of mycorrhizae with phosphate Rock plus half the fertilizer recommendation (MR) with 10% of vermicompost tea, then the treatment of mycorrhizae with azotobacter plus half of the fertilizer recommendation (MA) with 10% of vermicombe tea. Then the two treatments of mycorrhizae (M) and azotobacter (A) separately, while finally came the treatment of chemical fertilization (S), which gave the lowest values to the mentioned properties in the soil and plants.

The Improvement of Fluorescence In Situ Hybridization Technique Based on Explorations of Symbionts in Cicadas.

Fluorescence in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes is widely used for the identification of microbes in complex samples, but it suffers from some limitations resulting in the weak or even absence of fluorescence signals of microbe(s), which may lead to the underestimation or misunderstanding of a microbial community. Herein, we explored symbionts in the bacteriomes and fat bodies of cicadas using modified FISH, aiming to improve this technique. We initially revealed that the probes of Candidatus Sulcia muelleri (Sulcia) and the yeast-like fungal symbiont (YLS) are suitable for detection of these symbionts in all cicadas and some other species of Auchenorrhyncha, whereas the probe of Candidatus Hodgkinia cicadicola (Hodgkinia) is only suitable for detection of Hodgkinia in a few cicada species. The fluorescence signal of Sulcia, Hodgkinia and YLS exhibited weak intensity without the addition of unlabeled oligonucleotides (helpers) and heat shock in some cicadas; however, it can be significantly improved by the addition of both helpers and heat shock. Results of this study suggest that heat shock denaturing rRNA and proteins of related microbe(s) together with helpers binding to the adjacent region of the probe's target sites prevent the re-establishment of the native secondary structure of rRNA; therefore, suitable probe(s) can more easily access to the probe's target sites of rRNA. Our results provide new information for the significant improvement of hybridization signal intensities of microbes in the FISH experiment, making it possible to achieve a more precise understanding of the microbial distribution, community and density in complex samples.

Numerical Investigation of Radiative Hybrid Nanofluid Flows over a Plumb Cone/Plate

Non-Newtonian fluids play a crucial role in applications involving heat transfer and mass transfer. The inclusion of nanoparticles in these fluids improves the efficiency of heat and mass transfer processes. This study employs a numerical solution approach to examine the flow of non-Newtonian hybrid nanofluids over a plumb cone/plate surface, considering the effects of magnetohydrodynamics (MHD) and thermal radiation. Additionally, we investigate how heat and mass transfer are affected by a fluid containing microorganisms. The governing nonlinear partial differential equations are transformed into nonlinear ordinary differential equations using a similarity transformation to simplify this complex system. We then use the Keller-box finite-difference method to solve these equations. Along with a table presenting the results for skin friction, Nusselt number, Sherwood number, and microbe density number, we present graphical representations of velocity, temperature, concentration, and microorganism diffusion behavior. Our results indicate that the addition of MHD and thermal radiation improves the diffusion of microorganisms, thereby enhancing the rates of heat and mass transfer. Through a comparative analysis with prior research, we demonstrate the reliability of our conclusions.

Compost and humic acid amendments are a practicable solution to rehabilitate weak arid soil for higher winter field pea production

Arid soils are often weak, low in fertility, and lack essential plant nutrients. Organic amendments might be a feasible solution to counter the detrimental impact and rehabilitate weak arid soil for the growth of legumes. The study aimed to investigate how organic amendments of compost and humic acid may affect winter field pea productivity in arid soil. Over 2 years of field experiments, a range of treatments were applied, including different amounts of compost and humic acid. The results showed higher microbial carbon (C), and nitrogen (N) biomass, root length, shoot length, grains pod−1, and grain yield of pea, gained from the collective application of 8 Mg ha−1 compost and 15 kg ha−1 humic acid compared to all other treatments. Organic amendments increased soil microbial C density by 67.0 to 83.0% and N biomass by 46.0 to 88.0% compared with the control. The combined application of compost and humic acid increased soil microbial N biomass by 57.0 to 60.0% compared to the sole applications of compost-only and humic acid-only. It was concluded that organic amendments of 8 Mg ha−1 compost and 15 kg ha−1 humic acid in arid soil modulated microbial density, resulting in improved winter field pea productivity. This study suggests organic amendments of compost and humic acid might be a practicable solution to rehabilitate weak arid soil to grow legumes.

Exploring dose–response relationships in Aedes aegypti survival upon bacteria and arbovirus infection

A detailed understanding of how host fitness changes in response to variations in microbe density (an ecological measure of disease tolerance) is an important aim of infection biology. Here, we applied dose–response curves to study Aedes aegypti survival upon exposure to different microbes. We challenged female mosquitoes with Listeria monocytogenes, a model bacterial pathogen, Dengue 4 virus and Zika virus, two medically relevant arboviruses, to understand the distribution of mosquito survival following microbe exposure. By correlating microbe loads and host health, we found that a blood meal promotes disease tolerance in our systemic bacterial infection model and that mosquitoes orally infected with bacteria had an enhanced defensive capacity than insects infected through injection. We also showed that Aedes aegypti displays a higher survival profile following arbovirus infection when compared to bacterial infections. Here, we applied a framework for investigating microbe-induced mosquito mortality and details how the lifespan of Aedes aegypti varies with different inoculum sizes of bacteria and arboviruses.

Radiative ternary nanoliquid flow over an exponentially stretching sheet with motile oxytactic microorganisms

This article examines the mixed convection ternary nanoliquid flow containing a suspension of oxytactic microorganisms under the impact of nonlinear thermal radiation. The potential applications include microbiology, biotechnology, biosensors, cell therapy, medication release system, and protein expression. The governing equations that handle the problem are partial differential equations, they are dimensional, nonlinear in nature, and are nondimensionalized by using nonsimilar transformations. Further, for the computation of mathematical analysis, the Quasilinearization technique and numerical method such as the implicit finite difference scheme are used. The impacts of varying relevant factors on velocity, temperature, and microbe density are thoroughly examined. Results designate that the radiation factor favorably affects the velocity and temperature profiles. The rate of mass transport of liquid oxygen rises by about 45% when the Schmidt number grows from 1 to 2. The coefficient of skin friction is found to be more for ternary nanofluid than hybrid nanoliquid and nanoliquid. The current analysis compares the solution to earlier literature and finds that there is a good agreement.

Homotopic simulation of MHD bioconvective flow of water-based hybrid nanofluid over a thermal convective exponential stretching surface

PurposeWhilst a modest number of investigations have been undertaken concerning nanofluids (NFs), the exploration of fluid flow under exponentially stretching velocities using NFs remains comparatively uncharted territory. This work presents a distinctive contribution through the comprehensive examination of heat and mass transfer phenomena in the NF ND–Cu/H2O under the influence of an exponentially stretching velocity. Moreover, the investigation delves into the intriguing interplay of gyrotactic microorganisms and convective boundary conditions within the system.Design/methodology/approachSimilarity transformations have been used on PDEs to convert them into dimensionless ODEs. The solution is derived by using the homotopy analysis method (HAM). The pictorial notations have been prepared for sundry flow parameters. Furthermore, some engineering quantities are calculated in terms of the density of motile microbes, Nusselt and Sherwood numbers and skin friction, which are presented in tabular form.FindingsThe mixed convection effect associated with the combined effect of the buoyancy ratio, bioconvection Rayleigh constant and the resistivity due to the magnetization property gives rise to attenuating the velocity distribution significantly in the case of hybrid nanoliquid. The parameters involved in the profile of motile microorganisms attenuate the profile significantly.Practical implicationsThe current simulations have uncovered fascinating discoveries about how metallic NFs behave near a stretched surface. These insights give us valuable information about the characteristics of the boundary layer close to the surface under exponential stretching.Originality/valueThe novelty of the current investigation is the analysis of NF ND–Cu/H2O along with an exponentially stretching velocity in a system with gyrotactic microorganisms. The investigation of fluid flow at an exponentially stretching velocity using NFs is still relatively unexplored.

Analysis of activation energy and microbial activity on couple stress nanofluid with heat generation

This investigation includes the performance of the Couple Stress Nanofluid with microbial activity, activation energy incorporation of thermal conductivity, heat generation, variable viscosity and other parameters. We used some suitable similarity transformations to convert the governing partial differential equations and the initial boundary conditions of our model into the coupled structure of ordinary differential equations and final boundary conditions. Furthermore, the Spectral Quasi Linearization Method (SQLM) was used to numerically solve these ordinary differential equations with boundary conditions, generating the reassuring impacts of various parameters taken in our model. The graphical representation for the flow, temperature, solute and microbial distribution was analyzed with activation energy, heat generation and other interesting parameters. The impact of variable viscosity and thermal conductivity with the Prandtl number for the local skin friction, Nusselt, Sherwood, and the microbial density numbers was included and reflects the favorable results. The comparison table is also included to validate our model. The rising values of the activation energy parameter enhances the solute and microbe profiles, while rising of bio-convection Rayleigh number and Reynolds numbers discriminates the heat profiles, but enhances the solute profile. The microbial profile of the model falls for the rising values of the microbe reaction parameter.

63 Effect of elexacaftor-ivacaftor-tezacaftor on microbial density and microbiome composition in children with cystic fibrosis

63 Effect of elexacaftor-ivacaftor-tezacaftor on microbial density and microbiome composition in children with cystic fibrosis

Bioconvective periodic MHD Eyring-Powell fluid flow around a rotating cone: Influence of multiple diffusions and oxytactic microorganisms

Investigating the effects of periodic magnetic field and triple diffusion on bioconvection flow through a rotating cone populated by oxytactic bacteria and an Eyring-Powell fluid is innovative and significant. The magneto-bioconvection flow of an Eyring-Powell multi-diffusive fluid across a spinning cone is investigated in this paper, considering the effect of oxytactic microorganisms. The non-similar technique is used in the mathematical analysis of the flow over a spinning cone. The flow under consideration contains two diffusive species: liquid hydrogen and liquid oxygen. In light of the periodic magnetic field, the surface gradients, notably skin friction, exhibit wavy effects in the boundary layer domain. The governing equations for the fluid flow in the current flow problem, accompanied by heat diffusion, species diffusion, rotation, bioconvection, and periodic magnetic, are highly coupled nonlinear PDEs dependent on the proper initial and boundary conditions. Mangler's transformations convert them into non-dimensional forms, and numerical non-similar solutions are produced using implicit finite difference approximation and quasi-linearisation. The enriching values of bioconvective Rayleigh number Rb decline the velocity F, as a result, lessen the friction between the surrounding fluid and the cone's surface. The improving Peclet number Pe and microbial density difference σ reduced the microorganism density profile and heightened the microorganism density number Re-1/2Nn.