Concentration Of Microorganisms Research Articles

ENTEROCOCCUS FAECALIS AS AN ETIOLOGICAL FACTOR OF PURULENT PROCESSES IN SURGICAL PATIENTS: ANALYSIS OF BACTERIOLOGICAL RESEARCH RESULTS

Introduction. Opportunistic infections are often caused by microorganisms that are part of the normal human body microflora. Studying the role of microbiota in infectious pathology and the mechanisms of interaction between opportunistic microorganisms in microbial associations is crucial. Enterococcus faecalis is one such microorganism found in bacterial associations. The purpose of this study was to investigate the frequency of detecting E. faecalis in monoculture and as part of associations, the qualitative and quantitative composition of these associations, and the analysis of the variability in the pathogen’s susceptibility to antibiotics. Results and discussion. Out of 123 samples studied, Enterococcus bacteria were cultured in 38 cases, accounting for 30.9%. E. faecalis was isolated in monoculture in only 24.2% of all cultures of this species. Moreover, it was isolated in clinically significant concentrations (≥105 bacterial cells per 1 ml of the studied material) in only four out of eight cases. There is a difference in the susceptibility of cultures for groups of isolates where the concentration of microorganisms in the test material is <105 and ≥105 microbial cells per 1 ml. Conclusion. E. faecalis was present in 26.8% of isolates obtained from patients in the surgical department with purulent-inflammatory diseases. E. faecalis is mainly found in microbial associations. The susceptibility of E. faecalis to most of the antibiotics used in the study is higher in the group of isolates where this species of microorganism was present in concentrations equal to or higher than 105 microbial cells per 1 ml of the test material.

Gyrotactic bio-magneto-convective combined impacts on magnetorheological hybrid nanoflow: Microbial life on surfaces’ application

Magnetorheological fluid with self-driven ubiquitous motile organisms was affected by various physical factors such as hydrodynamics, dispersion, and distribution of organisms. These fascinating properties attracted us to work on this paper, a Casson hybrid nanoflow model exploring the dynamic behavior of microorganisms along spongy extensible surfaces taking Ohmic heating and chemical reaction into account. Further, the heat transfer phenomena are analyzed in the presence of thermal radiation and space and time-dependent energy sources/sinks. The nanoflow has its base methanol and a mixture of iron and aluminum oxides is suspended. Flow obeying mathematical model is solved numerically using the Runge–Kutta–Fehlberg technique along with the shooting method after imposing self-similarity transformation. Results of various pertinent parameters on the flow characteristic quantities and engineering quantities are portrayed and presented through graphs and tables. Iron oxide methanol nanofluid shows supremacy over hybrid nanoflows as speed is considered, whilst the opposite phenomenon is observed in the case of energy. Hybrid nanoflow makes the surface friction-free. Microorganism concentration difference improvement also helps in the intensification of motile organism growth.

Effects of Speleotherapy on Aerobiota: A Case Study from the Sežana Hospital Cave, Slovenia

Speleotherapy is one of the non-pharmacological methods for the treatment and rehabilitation of patients with chronic respiratory diseases, especially those with chronic obstructive pulmonary disease (COPD) and asthma. On the one hand, one of the alleged main advantages of speleotherapeutic caves is the low microbial load in the air and the absence of other aeroallergens, but on the other hand, due to the lack of comprehensive air monitoring, there is little information on the pristine and human-influenced aerobiota in such environments. The aim of this study was to assess the anthropogenic effects of speleotherapy on the air microbiota and to investigate its potential impact on human health in Sežana Hospital Cave (Slovenia). From May 2020 to January 2023, air samples were collected in the cave before and after speleotherapeutic activities using two different volumetric air sampling methods—impaction and impingement—to isolate airborne microbiota. Along with sampling, environmental data were measured (CO2, humidity, wind, and temperature) to explore the anthropogenic effects on the aerobiota. While the presence of patients increased microbial concentrations by at least 83.3%, other parameters exhibited a lower impact or were attributed to seasonal changes. The structure and dynamics of the airborne microbiota are similar to those in show caves, indicating anthropization of the cave. Locally, concentrations of culturable microorganisms above 1000 CFU/m3 were detected, which could have negative or unpredictable effects on the autochthonous microbiota and possibly on human health. A mixture of bacteria and fungi typically associated with human microbiota was found in the air and identified by MALDI-TOF MS with a 90.9% identification success rate. Micrococcus luteus, Kocuria rosea, Staphylococcus hominis, and Staphylococcus capitis were identified as reliable indicators of cave anthropization.

Use of Antibiotics and Probiotic Lactobacilli in the Treatment of Preterm Premature Rupture of Membranes: a Review

ABSTRACT To review the current evidence of the potential use of antibiotics and probiotics Lactobacillus in preterm premature rupture of membranes cases and to see the effect on microorganism concentrations especially Streptococcus agalatiae and Lactobacillus. This review used several databases (Google Scholar, Pubmed, and Science Direct) and searched for English and Indonesian articles in the last ten years. Articles were received in the form of case reports, observational studies and clinical trials that discussed the use of antibiotics and probiotic Lactobacillus in premature rupture of membranes especially in preterm pregnancy. After searching the database and eliminating duplicates and articles unrelated to the topic, we included some articles in this review. Prophylactic antibiotics are also expected to prolong the latent phase, thereby reducing the risk of fetomaternal morbidity and mortality. Penicillin is often recommended in preterm PROM, because broad-spectrum antibiotics are better as infection prophylaxis. Providing alternative therapy with lactobacillus probiotics is believed to prevent preterm birth and has the benefit of being a safe and effective therapy in restoring normal vaginal microflora and preventing vaginal infections during pregnancy. However, further research is needed to see the effectiveness of lactobacillus probiotics and look at the concentration of microbes, especially Streptococcus agalctiae and Lactobacillus. Keywords: Preterm Premature Rupture of Membranes, Antibiotics, Probiotics Lactobacillus, Streptococcus Agalactiae

A semi-analytical strategy for mixed convection non-Newtonian nanofluid flow on a stretching surface using Cattaneo-Christov model

This study investigates flow of non-Newtonian fluid containing nano particles and gyrotactic micro-organisms on stretching surface considering magnetic factor and thermal radiations. Cattaneo-Christov model is employed to analyze flow characteristics. The governing Partial Differential Equations (PDEs) along with associated boundary conditions describing the model are converted into Ordinary Differential Equations (ODEs) by suitable transformations. Homotopy Analysis Method (HAM), a semi-analytic solution technique is employed to obtain the solutions. The inspiration of important embedding variables on velocity, temperature, and concentration profiles are presented in tabular and graphical form to elaborate flow properties. It is deduced that the convective parameter and Weissenberg number, both have positive effect on dimensionless velocity whereas buoyancy ratio factor, bio-convective Rayleigh number, and magnetic force have inverse relationship with velocity profile. The presence of radiations and Brownian motion parameter boost energy transfer while it diminishes for higher Prandtl number values and mixed convection factor. Concentration intensifies for larger Prandtl number, activation energy, and thermophoresis parameters whereas it decreases for increasing temperature difference, Brownian motion, Schmidt number, and mixed convection factor. Bio-convective Peclet number, Lewis number, and microorganism concentration gradient factor, all depreciate microorganism concentration panel.

Uncontrolled Post-Industrial Landfill-Source of Metals, Potential Toxic Compounds, Dust, and Pathogens in Environment-A Case Study.

The aim of this case study was the evaluation of the selected metals' concentration, potential toxic compound identification, cytotoxicity analysis, estimation of the airborne dust concentration, biodiversity, and number of microorganisms in the environment (leachate, soil, air) of the biggest uncontrolled post-industrial landfills in Poland. Based on the results obtained, preliminary solutions for the future management of post-industrial objects that have become an uncontrolled landfill were indicated. In the air, the PM1 fraction dominated, constituting 78.1-98.2% of the particulate matter. Bacterial counts were in the ranges of 9.33 × 101-3.21 × 103 CFU m-3 (air), 1.87 × 105-2.30 × 106 CFU mL-1 (leachates), and 8.33 × 104-2.69 × 106 CFU g-1 (soil). In the air, the predominant bacteria were Cellulosimicrobium and Stenotrophomonas. The predominant fungi were Mycosphaerella, Cladosporium, and Chalastospora. The main bacteria in the leachates and soils were Acinetobacter, Mortierella, Proteiniclasticum, Caloramator, and Shewanella. The main fungi in the leachates and soils were Lindtneria. Elevated concentrations of Pb, Zn, and Hg were detected. The soil showed the most pronounced cytotoxic potential, with rates of 36.55%, 63.08%, and 100% for the A-549, Caco-2, and A-549 cell lines. Nine compounds were identified which may be responsible for this cytotoxic effect, including 2,4,8-trimethylquinoline, benzo(f)quinoline, and 1-(m-tolyl)isoquinoline. The microbiome included bacteria and fungi potentially metabolizing toxic compounds and pathogenic species.

Air Microbial Contamination and Risk of Respiratory Exposure of Workers in Chicken Farms

Animal farms are important sources of microbial contamination in the air environment. However, there are few reports on the time-regularity characteristics of airborne microbial contamination in farms. In the context of this situation, a study was conducted for more than 80 weeks using 16S rRNA gene amplicon sequencing to characterize the bacterial distribution and respiratory exposure in the farm air and fecal environment, respectively, taking a layer farm as an example. The results showed that 16S rRNA concentrations in air and manure samples ranged from 6.08×105-4.90×106 copies·m-3 and 4.27×108-1.15×1010 copies·g-1, respectively. The mean values of airborne bacterial concentrations were significantly higher in winter than in summer, whereas the biodiversity showed the opposite trend. The dominant bacterial phylum in both air and manure in the layer farm was Firmicutes. During the investigated time, the top three dominant genera in the air were relatively stable, in the order of Lactobacillus, Bacteroides, and Faecalibacterium, whereas the dominant genera in feces fluctuated with the increase in breeding time. The correlation between the community structure of bacteria and pathogenic bacteria in both air and manure was not significant, but the concentrations of both target microorganisms in different media were significantly correlated. The bioaerosolization index of bacteria in manure showed an increasing trend with increasing breeding time, whereas the opposite trend was observed for pathogenic bacteria. In this case, [Ruminococcus]_torques_group, Bacteroides, and Faecalibacterium were the top three pathogenic genera that were the most prone to aerosolization. There were seasonal differences in bacterial respiratory exposures of chicken farm workers, with mean intake values of 2.54×107 copies·d-1 and 2.87×105 copies·d-1 for bacteria and pathogenic bacteria, respectively. The results of this study will provide a scientific basis for systematically assessing the contamination characteristics and potential health risks of airborne microorganisms on farms and for developing corresponding industry standards for occupational exposure and prevention and control measures.

Air quality assessment in (semi) liquid food packaging environments

This study aimed to assess the prevalence of airborne microorganisms within the packaging areas of (semi) liquid food product facilities, considering the impact of outdoor microbiological air, seasonal fluctuations, rural-urban differences and environmental parameters such as temperature and relative humidity. Additionally, the effectiveness of both natural ventilation and air handling units were evaluated against total viable and non-viable particulate matter.Air samples were collected from the packaging areas of fourteen diverse (semi) liquid food producers and the outdoor environment in Flanders, Belgium, over the course of four separate days from January to September 2022. Airborne microorganisms, including total mesophilic plate count (TMPC) and yeast and mould (Y&M) count, were sampled using impaction and settle plate methods on Plate Count Agar and Rose Bengal Chloramphenicol agar, respectively. Simultaneously, a laser particle counter was used to collect and categorise particles into six size-based channels, while environmental parameters were monitored using a hygrometer.The study revealed a wide range of concentrations of airborne microorganisms across various companies (indoor TMPC ranging from 1.35 ± 0.65 log cfu/m3 to 3.42 ± 0.16 log cfu/m3 and Y&M count ranging from 1.22 ± 0.65 log cfu/m3 to 3.10 ± 0.08 log cfu/m3), irrespective of outdoor air quality. Neither relative humidity nor temperature exhibited any influence on TMPC and Y&M count. Companies equipped with high-efficiency filter air handling unit showed decreased concentrations of airborne microorganisms, although this trend did not align with their total particle counts. Moreover, no correlation was observed between total particle count and either TMPC or Y&M count. Additionally, impaction and sedimentation methods demonstrated a strong correlation.In conclusion, the diversity in airborne microorganism concentrations within food packaging areas is influenced by multiple factors, with air handling unit filters playing a pivotal role. High-efficiency filters were found to reduce microorganism levels, but their impact on total particle counts was less pronounced.

Prevalence and Concentration of Airborne Microorganisms Isolated from Domestic Toilets in Port Harcourt, Rivers State, Nigeria

Introduction: Microorganisms are ubiquitous in nature and transient airborne microorganisms have been shown to constitute major health hazards.
 Aim: This study was carried out to assess the microbial air quality in ten (10) domestic toilets located in mile-3, Alakahia, Choba, Ada-George and Rumuokwuta, Port Harcourt, Rivers state, Nigeria.
 Methodology: Microbial air quality was sampled using sedimentation techniques. Freshly prepared Nutrient Agar, MacConkey and Sabouraud Dextrose Agar (SDA) plates were placed one meter above the floor of the toilets for 1 hours at different sections of each toilet exposed to an open air. The agar plates were closed and transported to the Laboratory were incubation took place at 37°C for 24 hours and 25°C for 3-5 days for growth of bacteria and fungi respectively. Isolates were characterized and identified by standard microbiological methods.
 Results: The bacteria isolated were Staphylococcus species 22(22.45%), Bacillus species 20 (20.41%), Enterococcus species 20(20.41%), Escherichia coli 16(16.32%), Micrococcus species 15 (15.31%), Klebsiella species 3(3.06%), and Proteus species 2(2.04%) while Aspergillus species 14(27.45%), Penicillium species 16(23.53%), Fusarium species 10(19.60%), Mucor species 8(15.69%), and Rhizopus species 7(13.73%) were the fungi identified. The highest bacteria colony count before and after flushing were 52.380×103CFU/m3/hr & 67.261× 103CFU/m3/ hrrespectively while the lowest bacteria counts observed before and after flushing 19.047× 103CFU/m3/hr & 39.286×103CFU/m3/hr while the highest and lowest fungal count before and after flushing were 10.119×103CFU/m3/hr & 13.690×103CFU/m3/hr and 5.952×103CFU/m3/hr & 5.953×103CFU/m3/hr respectively.
 Conclusion: This study shows that considerable numbers of both pathogenic bacteria and fungi particles were released into the air in higher quantity after flushing domestic toilets when compared to air quality before flushing. These organisms have been implicated in major and minor infectious diseases. Inhalation or contact may easily lead to infection especially in immunocompromised individuals and the older adults. To maintain the health of users, it is necessary to carefully manage the environmental factors that promote the growth and multiplication of microorganisms in domestic toilet environment.

From remote to urbanized: Dispersal of antibiotic-resistant bacteria under the aspect of anthropogenic influence

Antibiotic resistance is a growing global concern, but our understanding of the spread of resistant bacteria in remote regions remains limited. While some level of intrinsic resistance likely contributes to reduced susceptibility to antimicrobials in the environment, it is evident that human actions, particularly the (mis)use of antibiotics, play a significant role in shaping the environmental resistome, even in seemingly distant habitats like glacier ice sheets.Our research aims to bridge this knowledge gap by investigating the direct influence of human activities on the presence of antibiotic-resistant bacteria in various habitats. To achieve a comprehensive assessment of anthropogenic impact across diverse and seemingly isolated sampling sites, we developed an innovative approach utilizing Corine Land Cover data and heatmaps generated from sports activity trackers. This method allowed us to make meaningful comparisons across relatively pristine environments.Our findings indicate a noteworthy increase in culturable antibiotic-resistant bacteria with heightened human influence, as evidenced by our analysis of glacier, snow, and lake water samples. Notably, the most significant concentrations of antibiotic-resistant and multidrug-resistant microorganisms were discovered in two highly impacted sampling locations, namely the Tux Glacier and Gas Station Ellmau.

Comparison of the bioaccumulation and biosorption of copper ions by Rhizopus delemar and Candida lipolytica

In this study, the bioaccumulation of Cu(II) ion by Rhizopus delemar and Candida lipolytica was investigated and the bioaccumulation and biosorption of Cu(II) ions by Candida lipolytica compared. The specific growth rate and the maximum microorganism concentration of both microorganisms increased with increasing initial molasses concentration whereas decreased with increasing initial Cu(II) ion concentrations up to 250 mg/L. Accoding to Monod equation, the maximum specific growth rate and saturation constant for C. lipolytica and R. delemar were determined as 0.335 h−1-32.330 g/L and 0.406 h−1-24.182 g/L, respectively. The bioaccumulation efficiencies of R. delemar and C. lipolytica were determined as 74.18% and 67.30% in the presence of 50 mg/L Cu(II), respectively. At pH 4.0, the maximum biosorption rate (4.72 mg/g min) and the biosorbed Cu(II) ion concentration (49.0 mg/L) were obtained for C. lipolytica and these values increased with increasing Cu(II) concentration. Cu(II) biosorption by C. lipolytica fitted well to the Langmuir isotherm model and pseudo-second-order kinetic model and maximum adsorption capacity was found as 114.942 mg/g. The bioaccumulated Cu(II) was found to be 21.5 mg/g whereas the amounts of biosorbed Cu(II) were calculated as 53 mg/g by C. lipolytica at a concentration of 100 mg/L of Cu(II).

Numerical study of hydromagnetic bioconvection flow of micropolar nanofluid past an inclined stretching sheet in a porous medium with gyrotactic microorganism

The present article centers on the examination of novel bioconvection phenomena involving gyrotactic microorganisms and a micropolar nanofluid model with hydro-magnetic flow. The flow traversed a stretchable inclined plate within the permeable medium. Heat absorption and thermal radiation are considered. The objective of this study is to assess the rate of heat transfer exhibited by nanofluid when unicellular microorganisms are present. Mathematical complex flow model is converted to nonlinear dimensional less system of differential equation through adopting the appropriate similarity variables. For the non-linear nanofluid problem, the (FDM) finite difference method (Lobatto IIIA) is applied with a range of collocation sites and an accuracy of order 4–5. (Lobatto IIIA) excels in solving coupled differential equations, even those with high nonlinearities. Nanofluid containing gyrotactic microbes is highly applicable in bioscience, geoscience and eco science. The effects of dimensional less parameters on flow field, energy distribution, nanofluid concentration and density of microorganism concentration profiles analyzed through the graphical and tabulation representation. This basic research will aid scientists and engineers in controlling fluid flow and improving complex systems that make use of it.

Stabilization of biomass in manure effluent using the thermophilic-aerobic process

Aerobic-thermophilic stabilization of biomass is crucial in improving the processing processes of manure. This method makes it possible to achieve effective and stable processing of organic materials contained in manure using aerobic microorganisms and elevated temperatures. The aerobic-thermophilic process includes the action of oxygen and high temperature, which contribute to the active decomposition of organic substances in manure runoff. The increased temperature helps to create optimal conditions for the action of thermophilic bacteria, which accelerates the process of biological decomposition. Studies show that aerobic-thermophilic treatment of manure effluents helps to reduce the concentration of pathogenic microorganisms and ammonia. This contributes to obtaining cleaner and environmentally safe manure suitable for use in agriculture. Advantages of aerobic-thermophilic stabilization: Faster recycling process compared to traditional methods. Reduction of odors and risk of pathogen contamination. High quality and efficiency of produced manure. Aerobic-thermophilic stabilization of biomass in manure processing is a promising direction in improving modern waste treatment technologies. Its implementation contributes to improving the quality and safety of manure and the effective use of these resources in agriculture. Research and development of this method are essential for achieving sustainable and ecologically clean agricultural production. It has been established that liquid manure of enterprises with intensive milk and pork production technologies with hydraulic manure removal systems with a humidity of 92–96 % should be subjected to aerobic fermentation in an auto thermal mode, as a result of which products are obtained that are safe from a sanitary and hygienic point of view. In addition, the loss of nutrients is reduced. which determines the quality of organic fertilizers. Established that liquid manure businesses for technology-intensive milk production and pig manure removal by hydraulic systems with humidity 92–96 % of it are advisable to expose aerobic biofermentatsiyi in autothermal mode, which allows you to get the products in a safe sanitary and hygienic attitude and reduce the loss of nutrients that determine the quality of organic fertilizers.

Novel Bayesian distributed adaptive neural structure for titanium and aluminium alloy nanofluidic model with gyrotactic microorganisms

The purpose of this research study is to evaluate the solutions of Titanium and Aluminum alloy nanofluidic model with gyrotactic microorganisms (TAA-NFMGM) by applying stupendous knacks of Bayesian distributed adaptive neural structure (BDANS). The use of nanofluids containing gyrotactic microorganisms in combination with titanium and aluminum alloys have potential applications in diverse fields, including engineering, bioremediation, biomedical devices, biotechnology, and research depending on different factors like design of the system and use of certain microorganism. A dataset for BDANS is generated for the eight different events with Adam numerical technique for TAA-NFMGM by varying Prandtl number (Pr), mixed convection parameter (λ), microorganisms concentration parameter (Ω), bioconvection peclet number (Pe), and bioconvection Lewis number (Lb). The reference data set generated with Adam numerical technique is utilized for numerical calculation of different parameters on TAA-NFMGM by employing the artificial intelligence based BDANS. The accuracy and justification of the performance of BDANS is efficaciously substantiated through negligible level of MSE around 10–10 to 10–13, calculation of regression metrics and distribution of instances of error on histograms with values 10–04 to 10–09 near to reference line.

Growth Response of Mucuna bracteata with the Application of Local Micro Organisms (LMO) of Banana Weevil

This research aims to determine the effect of concentration and duration immersion giving LOM banana weevil against the gowth of Mucuna bracteata. The research was conducted in the garden of Jalan Setia Bangun Pasar III, Sei Beras Sekata, Kecamatan sunggal, Kabupaten Deli Serdang, Sumatra utara and continued in the laboratory of the Indonesian Oil Palm Research Institute (IOPRI). This research was started in April-June 2020. This study used a randomized complete block design (RCBD) factorial. The first factor was the concentration of local microorganisms (LMO) of Banana Weevil consisting of 4 levels, namely: Without treatment, 15%, 30%, 45%. The second factor. The duration of immersion consists of 4 levels, namely: No immersion time, 15 minutes, 30 minutes, 45 minutes. Observation data were analyzed usingDuncan's Multiple Range Test with a significant 5%. The results showed that the LMO concentration of banana weevil was effective in increasing the gowth of the number of leaves 39.77, tendril length 83.14 cm, shoot fresh weight 28.54 g, and shoot dry weight 6.03 g. The duration of soaking had a significant effect on the highest number of leaves at week 3 (9.63 pieces). The interaction application of banana weevil concentration and soaking time affected the number of root nodules (40.50 gains) and root dry weight (0.73) g of theplant Mucuna bracteata.

Identification of Airborne Aerobic Bacteria in the Intensive Care Room using MALDI-TOF MS

Introduction: Indoor air quality can affect the spread of airborne microorganisms which can lead to healthcare-associated infections (HAIs). The quality and quantity of airborne microorganisms are responsible for mortality and morbidity in infection-prone hosts such as patients admitted to the intensive care unit (ICU). The research aims to determine the quality of microorganisms in the air, identify the types of aerobic bacteria, and assess the physical parameters of the air in the ICU. Methods: This study was a cross-sectional study with a descriptive observational method. Air specimens were collected using the MAS-100 NT tool with blood agar plate solid culture media, which then incubated in an aerobic atmosphere for 24 hours at 37±2°C. Observation and measurement of air microbiological quality was by counting the number of microorganisms in CFU/m3 and identification of bacteria using MALDI-TOF MS. Results and Discussion: The maximum concentration of microorganisms in the air exceeds the standard value, and the average value of the concentration of microorganisms in the air is 736 CFU/m3. The most common types of aerobic bacteria in the air were Bacillus sp. (n=12), Coagulase-negative Staphylococci (n=5), and Staphylococcus aureus (n=5). There was an increase in physical parameters in the form of average temperature (26.24°C) and humidity (70%) with a ventilation system and air regulation using mechanical ventilation sourced from a split air conditioner with an exhaust fan without a high-efficiency particulate-absorbing (HEPA) filter. Conclusion: Low indoor air quality has the potential to increase the concentration of microorganisms and bacterial findings in the air

Magnetohydrodynamic thermo-bioconvective flow of 3D rotating Williamson nanofluid with Arrhenius activation energy in a Darcy–Forchheimer medium over an exponentially stretching Surface

This paper aims to analyze the heat and mass transfer characteristics of the 3D thermo-bioconvective flow of rotating Williamson nanofluid over an exponentially stretching vertical sheet. The flow distribution considers the influence of nonlinear thermal radiation, Hall and ion-slip currents, joule heating, coupled effects of Dufour and Soret diffusion, internal heat generation, Arrhenius activation energy, Brownian, and thermophoresis diffusion in a Darcy–Forchheimer porous medium. The modeled partial differential equations (PDE) in terms of continuity, momentum, energy, concentration, and density of motile microorganisms are reformed into ordinary differential equations (ODE) forms employing similarity variables. The resulting equations are solved numerically using the spectral local linearization method (SLLM). The successive over-relaxation technique is applied to accelerate and enhance the convergence of the method. The obtained results are graphically and tabularly represented and numerically explored for the effects of pertinent parameters on the velocity, temperature, nanoparticle concentration, and motile microorganism concentration profiles. The rotation and mixed convection parameters dropped the primary velocity curve, while the Williamson and heat source parameters uplifted the microbes density distributions. The temperature field rises with an increase in radiation and microbes Brownian motion and declines with an increase in Hall and ion-slip numbers. Furthermore, with the increase in activation energy from 0.5 to 2 and the mixed convection parameter from 0.6 to 1.3, we observe a respective 3.93% rise and 8.30% fall in mass transfer rates. The current investigation has broad applications, including MHD accelerators, biotechnology, the formation of elastic sheets, the production of polymer solutions, and the synthesis of nanoparticles through microbial processes.

Residence time and the concentration of microorganism in the ozone contactor: a CFD simulation on chamber deflectors.

Disinfection is an important step in deep drinking water treatment technology. This study applies computational fluid dynamics to investigate and optimize the hydrodynamics inside the ozone contactor. ANSYS Fluent was used to solve all the control equations. A step method is used to simulate the residence time distribution. The mean residence time is simulated under the Eulerian framework. The deflectors are installed in chambers to direct flow. The deflectors allow for a more uniform flow and a longer mean residence time within the contactor. The baffling factor showed that the deflectors could reduce the short-circuit effect in the contactor and improve the disinfection efficiency by 34.6% compared to the original reactor. The Morrill factor coefficient is improved by 22.8% compared to the original reactor. According to the Aral-Demirel index, contactors with deflectors are significantly better than other baffle-type contactors. The presence of the deflectors increased the microbial inactivation efficiency from 95.3 to 96.5%. The optimal deflector height should be controlled between 30 and 60 mm.

Bioconvection in a Porous Medium Saturated with a Casson Nanofluid

The bio-convective heat transfer of an incompressible, viscous, electrically conducting Casson nanofluid past a wedge has been analyzed. Furthermore, using a similarity variable, the governing flow equations are transformed to non-linear coupled differential equations corresponding to a two-point boundary value problem, which is solved numerically. A comparison of the solution technique is carried out with previous work and the results are found to be in good agreement. Numerical results for the coefficient of skin friction, Nusselt number, Sherwood number, micro-organism flux as well as the velocity, temperature, nanoparticles and micro-organisms concentration profiles are presented for different physical parameters. The analysis of the obtained results shows that the field of flow is significantly influenced by these parameters.

Efeito do óleo essencial de Mentha piperita na conservação de carne refrigerada do peixe híbrido tambatinga

Abstract The search for safer foods has led to increased research attention to discover natural alternatives to synthetic additives that are used in the food industry. Natural preservatives, such as essential oils (EOs) from plants, could increase fish conservation and even positively affect human health. Therefore, the objective of the study was to evaluate the effect of Mentha piperita EO on the physicochemical characteristics and concentration of microorganisms in chilled tambatinga (Colossoma macropomum × Piaractus brachypomum) meat. Mentha piperita EO was prepared at three concentrations (0%, 0.25% and 0.50%) in a solution containing distilled water, propylene glycol and Tween. The meat samples remained immersed in this solution for 60 min; then, they were packed in plastic packages and stored under refrigeration (± 0.4 °C) for 14 days. During this storage, pH, total volatile nitrogenous bases (TVB-N), peroxides, thiobarbituric acid reactive substances (TBARS) and counts of strict and facultative aerobic mesophilic microorganisms were determined. The major constituents found in M. piperita EO were geranial (32.28%), neral (18.64%) and geranic acid (6.98%). None of the EO concentrations affected TVB-N, but there were some changes to the pH. Both 0.25% and 0.50% EO reduced the formation of peroxides and TBARS. The growth of microorganisms was reduced by treatment with 0.50% EO. Based on the findings, 0.50% EO was more effective in reducing the deterioration of meat kept refrigerated for up to 14 days.