Effectiveness Of Strains Research Articles

Determination of the radioprotective effectiveness of inactivated gamma-irradiated strains of microorganisms

Determination of the radioprotective effectiveness of inactivated gamma-irradiated strains of microorganisms

The effect of a movable headrest in shoulder assist device for overhead work.

Recently, many kinds of shoulder-support exoskeletons have been developed and some of them are commercially available. However, to the best of our knowledge, shoulder-support exoskeletons that have neck-support mechanism have not been found. During the overhead work, physical strain is added to not only upper limb and shoulder but also neck of workers since the workers work keeping their face raised. Therefore, in this study, to reduce the physical strain on the neck during the overhead work, a movable headrest that can be attached to the shoulder assist device was developed, which has reclining and slide functions of a head. The main purpose of this article was to evaluate usefulness of the proposed movable headrest. To this end, measurements of electromyogram were carried out under simulating an overhead work activity, and the reduction effect for physical strain of the neck was compared among three types of headrests: (a) slide-type headrest which can slide the head backward and forward, (b) reclining-type headrest which can recline the head, and (c) reclining and slide-type headrest which can recline and slide the head. In addition, usefulness of the shoulder assist device with the proposed headrest was evaluated for a realistic overhead work activity through measurements of muscular stiffness of neck and shoulder. The experimental results showed that the existence of the headrest in the shoulder assist device is effective to reduce the physical strain to the workers, and that (c) reclining and slide-type headrest is the most effective among these three types of headrests.

Determination of prophylactic and therapeutic effectiveness of probiotic strain Escherichia coli 39-SN.

At present, it is relevant to preserve and raise healthy, well-developed newborn animals adapted to new conditions, which form the basis for increasing the yield of animal husbandry. Gastrointestinal diseases cause the main losses of young animals. Acute gastrointestinal diseases of calves, lambs, piglets, and chickens are widespread in Kazakhstan. The study aims to develop a competitive treatment and prophylactic drug composition based on probiotic bacterial strains. Modern certified and standardized biochemical, microbiological, molecular biological studies were considered during the research. The morphological, cultural, and biochemical properties of the cultures were studied according to generally accepted schemes. Standard methods of finding averages and their mean errors were used for the mathematical processing of results. Antibiotics, sulfonamide, and nitrofuran drugs are the most common methods to combat diseases in young animals. However, the use of antibacterial agents often leads to the death of normal microflora, disrupting the microbiocenosis of the gastrointestinal tract, the appearance of microorganisms with resistance to drugs, and a decrease in product quality. In this regard, the direction of biotechnology involved in the development and creation of environmentally friendly microbial preparations with prophylactic effectiveness is very relevant. Data on the prophylactic and therapeutic efficacy of the probiotic strain of Escherichia coli 39-SN are presented.

Delayed Lysis Time at High Multiplicities of Particles in a Chlorovirus-<i>Chlorella</i> Interaction

When viruses infect microbial cells, their phenotypes depend on the host's genotype and on the environmental conditions. Here we describe such an effect in laboratory strains of the chlorovirus PBCV-1 and its algal host Chlorella variabilis. We studied the growth of six virus isolates, and found that the mean lysis time was 1.34±0.05 times longer at multiplicity of particles (MOP) 10 than at MOP 1. We could not detect any associated changes in burst size. This is a novel plastic trait for chloroviruses, and we hypothesize that it is caused by our specific laboratory algae.

The influence of strain hardening and surface flank angles on asperity flattening under subsurface deformation at low normal pressures

Characterisation of model asperity flattening under longitudinal subsurface elongation is presented with a variety of normal pressure, flank angle and strain hardening behaviour. A systematic investigation outlines an optimal specimen design to ensure a homogenous deformation field in the workpiece under stress-strain conditions, which are typical in sheet metal forming. Asperity flattening increases with normal pressure, and the longitudinal subsurface strain reduces the necessary yield pressure and promotes asperity flattening. When the flank angle is increased, the longitudinal stress component due to elongation gets smaller in the asperity, reducing the effect of longitudinal straining. Strain hardening decreases the asperity flattening rate as strain hardening extends the deformation field further into the underlying material, which results in less asperity flattening.

Eradication therapy of helicobacteriosis with probiotics, problems, and prospects

Currently, there is an urgent question of optimizing the treatment of stomach diseases associated with Helicobacter pylori, due to the increasing resistance of the pathogen to antibiotics and the presence of side effects of standard therapy. To optimize it, it is proposed to use probiotics as an additional or monotherapy. The review presents the results of studies of anti-helicobacter activity by in vitro and in vivo systems, as well as an assessment of the clinical effectiveness of various probiotic strains of microorganisms in eradication therapy. Several mechanisms of action of probiotics in the treatment of HP-related diseases are discussed. The problems and prospects of using personalized therapy of helicobacteriosis with probiotics and autoprobiotics, based on strains obtained from the gastrointestinal tract, are indicated.

Gold-Specific Biosensor for Monitoring Wastewater Using Genetically Engineered Cupriavidus metallidurans CH34.

Transcription factor-based whole-cell biosensors have recently become promising alternatives to conventional analytical methods due to their advantage of simplicity, cost-effectiveness, and environmental friendliness. In this study, we used genetic engineering to develop a whole-cell biosensor based on the activation of promoters by CupR via interactions with gold ions, leading to the expression of reporter genes that yield output signals. Altering the promoter sequences was shown to significantly improve the performance of the biosensor strain in terms of gold-specificity. The detection sensitivity of our engineered strains was 42-fold higher than that of wild-type strains. The linear range of the purposed sensor was 125-1000 nM with a limit of detection at 46.5 nM. The effectiveness of the sensor strain was verified in wastewater samples.

Variation in porous media compositions influence the co-transport behavior of ZnO and FexOy mixed nanoparticles

The objective of this study is to evaluate the effect of porous media compositions on the co-transport behavior of nZnO-nFexOy-mix suspension. To achieve this objective, porous media compositions are altered by coating the natural sediment granule with humic acid (HA), nFexOy, and kaolin-clay particles. The nZnO-nFexOy-mix suspension is then injected through a series of a column packed with natural sediment and modified sand at pH 8 and in the presence of HA. The alteration in surface morphology after modification of sediment surface and deposition of ENPs is assessed using Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). The results indicate that significant amount of nZnO and nFexOy get transported through natural sediment when injected as ENP-mix (C/C0 = 0.57 and 0.66) or as individual entity (C/C0 = 0.65 and 0.70). However, a decrease in the transport of nZnO and nFexOy is observed when transported through HA-containing, nFexOy-containing and clay-containing sand packed column. The high retention of nZnO and nFexOy particles in those media is attributed to the combined effects of extensive straining and deposition. AFM and SEM image confirm more ENPs deposition on the collector surface when the sand is modified with HA-, nFexOy- and clay-containing sand. Charge screening and occurrence of homo and hetero-aggregation are the major attributing factors for enhanced deposition. In all the cases, pore-blocking due to the formation of a cluster like aggregates on the sand surface has resulted in enhanced straining. Whereas, for the case of clay-containing sand, straining is further enhanced due to a reduction in porosity. Overall, it can be concluded that there is a risk of groundwater contamination by nZnO and nFexOy when transported through natural sediment; however, the presence of natural organic matter, metal oxide nanoparticles, and clay in the natural soil can reduce the risk of contamination.

Effects of thermal expansion, strain rate, and gravity force on the steady propagation of a premixed flame in semi-closed channels

The flame dynamics of steady propagation of a premixed flame in semi-closed channels is investigated. The hydrodynamic model takes into account impacts of channel width, thermal expansion, straining effect, and downward gravity force on the flame front. The steady flame shape and its velocity field could be determined by numerical iteration of a weakly nonlinear front equation and linearized governing equations with Fourier transform, respectively. Results reveal that the introduction of thermal expansion and gravity force enhance the flame curvature and increase the burning velocity, while the straining effect suppresses the flame bending processes. In addition, a non-monotonic dependence of the burning velocity on the Peclet number is further demonstrated. It reveals that the thermal expansion and strain effect would have impacts on the burning velocity as well.

In Vitro Evaluation of the Effect of Oral Probiotic Weissella cibaria on the Formation of Multi-Species Oral Biofilms on Dental Implant Surfaces.

Oral probiotics are beneficial bacteria that can help prevent periodontal disease. However, little is known about the effects of oral probiotics on the formation of implant biofilms. This study aimed to evaluate the effects of oral probiotics Weissella cibaria CMU and CMS1 in an in vitro complex biofilm model on titanium implant surfaces. First, it was identified through colony biofilm assay that W. cibaria CMU and CMS1 inhibit the formation of multi-species biofilms formed by eight types of bacteria. Two types of saliva-coated titanium discs inoculated with early (Streptococcus gordonii, Streptococcus oralis, Streptococcus sanguinis, Actinomyces naeslundii, and Veillonella parvula), secondary (Fusobacterium nucleatum and Prevotella intermedia), and late (Porphyromonas gingivalis) colonizers were treated with the oral probiotics and then incubated anaerobically for three days. The effects of oral probiotics on titanium disc biofilm formation were analyzed using culture methods, quantitative polymerase chain reaction (qPCR), and microscopic analysis. Both probiotics significantly inhibited the formation of biofilm, and all eight bacterial species were significantly reduced. The effectiveness of both probiotic strains was confirmed by all the methods used. Oral probiotics may have dramatically reduced the biofilm formation of secondary colonizers that act as bridges, thus inhibiting biofilm formation on the titanium surface. Our results suggest that the probiotic W. cibaria offers new possibilities for the prevention of peri-implant mucositis.

Isolation of Photosynthetic Bacteria from Coal Mining Site Having Potential for Nitrate Removal

Wastewater is untreated water that has high amount of nutrients such as nitrate, phosphate, ammonium and chemical oxygen demand (COD). When it is discharged into watercourse, it affects human and aquatic biota. The application of photosynthetic bacteria is considered bio-friendly system than the conventional one. Hence, the present study investigates the effectiveness of robust strain of photosynthetic bacteria for nitrate removal under different concentrations of 85, 135, 190, 235 and 320 mg/L. Serial dilution techniques was used for the isolation of the bacteria. The results showed that three bacterial isolate were obtained and were both screened for nitrate reduction ability. The isolate was able to remove 91, 90, 71, 67 and 55% of nitrate at 85, 135, 190, 235 and 320 mg/L respectively. The bacteriochlorophyll of the isolate was detected at peak range between 689-710 nm. The morphological, physiological and biochemical characterization showed that the isolate was identified as Rhodopseudomonas sp. The nutrient removal yield of the nitrate under different concentrations was found to be at range of 0.01- 0.033 g-1 DCW g-1 NO3.- This study suggested that the strain could be used as an efficient bacterial candidate for the treatment of wastewater containing high amount of nitrate.

Mortalitas dan bobot badan tiga strain ayam broiler pada kepadatan kandang yang berbeda

The aim of this study was to analyze the effects of strain, density and their interaction on mortality and body weight of broiler chicken raised in the closed houses. The data was obtained from 60 broiler farms in the Central Java province. Three strains were Cobb, CP 707, and Loghman. The density level was classified into three groups: £10, >10 to <15, and ³ 15 birds/m2. Parameters observed were mortality and body weight in the first week to the fifth week (M1, M2, M3, M4, and M5) and (BB1, BB2, BB3, BB4 dan BB5), respectively. Test of significance effect for strain and density was performed using Mixed procedure of Statistical Analysis System (SAS) University Edition V.6p.2. software. The results showed that density was significant (P<0,01) on the first week (M1), their interaction was (P<0,01) on M1 and (P<0,05) on the fourth week (M4), but not significant on body weight. The conclusion from this study there was an interaction between genetic and environment on mortality one week after chick in and nearly harvesting.

Does Family Economic Strain Reduce Child Educational Achievement? A Longitudinal Assessment Using the Great Recession in Ireland

Abstract Although the association between family social position and children’s educational achievement has been repeatedly shown, evidence of what explains this association has been more elusive. We put forward two broad theories which have come to dominate the literature: the ‘family investments model’ (FIM) and the ‘family stress model’ (FSM). Using longitudinal cohort data from Growing Up in Ireland, a nationally representative cohort study of young people and propensity score methods to adjust for selection bias, we show that a family’s experience of economic strain can significantly reduce child attainment in state exams at age 15. Together, FIM and FSM measures explain between 36 per cent and 47 per cent of the effect of change in economic strain, but the variables associated with FSM explain more of the effect for economic strain than change in the variables associated with FIM. These results add to mounting evidence that psycho-social processes are at least as important, if not more important than human capital processes in explaining the effects of low resources on child health, education, and social development.

ANTIMICROBIAL PROPERTIES OF LIGNINE AS A NATURAL BIOCIDE FOR TEXTILE PROTECTION

The functionalization of antibacterial drugs is one of the important areas of research in the textile industry. It uses traditional antimicrobial agents of synthetic or natural origin, and generates new biopolymers with useful properties. Some of them, such as lignin and pectin, have good biocompatibility, antioxidant and antimicrobial properties, but the domestic market uses them mainly in the construction and food industries, respectively. The antimicrobial activity of sodium lignosulfonate, apple pectin and their mixture against gram-positive bacteria (Staphylococus aureus) and gram-negative strains (Escherichia coli, Pseudomonas aeruginosa) was studied. Experimental results have shown that lignin exhibits slightly higher antibacterial activity compared to pectin and is more effective against Staphylococcus aureus in terms of minimal bactericidal and minimal inhibitory concentrations. Determination of cytotoxicity of sodium lignosulfonate by MTT showed the non-toxicity of this biocide for human cells. It was found that the antimicrobial behavior of lignosulfonates, pectins and their mixtures differs in relation to gram-positive and gram-negative strains of bacteria. It appeared that the most vulnerable to bactericides are gram-positive strains of Staphylococcus aureus due to the possible absence of double-membrane wall cells. In addition, the simultaneous use of lignin and pectin as a synergistic mixture showed an increase in antibacterial action against all microorganisms by 2-4 times. The antimicrobial effect of the studied biocides was compared to the traditional antimicrobial drug argent nitrate, which is widely used in various industries, including textile production. It was found that lignin and pectin in amounts of 1-5 мг/см3 have the same antimicrobial effect for gram-positive strains and 10-20 мг/cм3 – for gram-negative bacteria, as a solution of AgNO3 with a concentration of 0.2 мг/см3. Higher concentrations of lignin and pectin can be offset by significantly lower prices compared to argentum salts, as well as greater environmental and medical safety for human health. In addition, lignin is potentially available in large quantities as a by-product from the pulp industry and lignocellulosic bioprocessing plants. This piece of work may be useful in future when creating antimicrobial compositions for textiles.

First-principles investigation on electronic structure, magnetic states and optical properties of Mn-doped SnS2 monolayer via strain engineering

Two-dimensional magnetic materials are high desirable for realizing advanced optoelectronic and spintronic devices. In this paper, we report systematic studies the effects of strain on the electronic structure, magnetic states and optical properties of Mn-doped SnS2 monolayer (ML) by means of first-principles calculations. Ab-initio molecular dynamics simulations and formation energy reveal that the Mn-doped SnS2 ML is stable at 500 K and can be fabricated under the S-rich condition. The substitution of a Mn for a Sn atom induces 3 μB magnetic moment in nonmagnetic SnS2 ML, which is consistent with the Hund's rule and Aufbau principle. Based on classical Heisenberg model and mean-field approximation the Curie temperature is calculated to be 476.13 K. Due to symmetry reserved crystal structure, the net magnetic moment of Mn-doped SnS2 ML is robust even if considerable strains (−10 to 10%) are applied. The blue-shift and red-shift of the absorption peaks are observed in the optical spectrum by biaxial compressive and tensile strains. The biaxial strain effectively improves the optical properties of Mn-doped SnS2 ML, particularly in the visible light region. This study provide useful guidance for practical application in magnetic and optoelectronic devices.

The determination of effective concentration of acethonilic Ipomoea cairica leaves extract against laboratory and field strains of Aedes albopictus and Aedes aegypti mosquito larvae.

Inundated with escalating dengue outbreaks, there is an urgent call to find alternate potential vector control methods as the currently employed method fails to curb the expanding of dengue virus transmission in Malaysia. Supported by this aim, we are interested in exploiting the potential of Ipomoea cairica leaves extract towards primary and secondary vectors of dengue fever, Aedes aegypti and Aedes albopictus. To assess the effectiveness of this plant extracts towards Aedes larvae, we carried out two complementary analyses. First, we observed the comparative effectiveness of larvicidal activity I. cairica extract against the laboratory and field strains of Ae. aegypti and Ae. albopictus. Then, we determined the effective lethal dose of this plant extract against Aedes larvae using log-probit regression analysis of the SPSS 20.0 programme. Results from bioassay demonstrated that I. cairica leaves extract was highly effective to induce larvicidal mortality of Ae. albopictus and Ae. aegypti within 24 and 48 hours post-treatment. Results from the factorial analysis of variance (ANOVA) also indicated that there were significant differences in larvicidal activity between species and strains used (P<0.05). It is interesting to notify that the sequence of effectiveness for the larvicidal activities of I. cairica acethonilic leaves extract is in the manner; Ae. albopictus field strain > Ae. aegypti laboratory strain > Ae. aegypti field strain > Ae. albopictus laboratory strain. The I. cairica leaves extract displayed high larvicidal activity against Ae. albopictus as compared to Ae. aegypti. This is the first evaluation involving the comparison of I. cairica leaves extract effects for the laboratory strain and field strain of Ae. albopictus and Ae. Aegypti.

Assessing effectiveness of Komagataeibacter strains for producing surface-microstructured cellulose via guided assembly-based biolithography

In this study, a medical device made of surface microstructured bacterial cellulose was produced using cellulose-producing acetic acid bacteria wild-type strains in combination with guided assembly-based biolithography. The medical device aims at interfering with the cell's focal adhesion establishment and maturation around implantable devices placed in soft tissues by the symmetrical array on its surface. A total of 25 Komagataeibacter strains was evaluated over a three-step selection. In the first step, the ability of strains to produce a suitable bacterial cellulose layer with high production yield was examined, then nine strains, with a uniform and smooth layer of bacterial cellulose, were cultured in a custom-made silicone bioreactor and finally the characteristics of the symmetrical array of topographic features on the surface were analysed. Selected strains showed high inter and intra species variability in bacterial cellulose production. The devices obtained by K2G30, K1G4, DSM 46590 (Komagataeibacter xylinus), K2A8 (Komagataeibacter sp.) and DSM 15973T (Komagataeibacter sucrofermentas) strains were pouched-formed with hexagonal surface pattern required for reducing the formation of fibrotic tissue around devices, once they are implanted in soft tissues. Our findings revealed the effectiveness of the selected Komagataeibacter wild-type strains in producing surface microstructured bacterial cellulose pouches for making biomedical devices.

Reassessment of modeling turbulence via Reynolds averaging: A review of second-moment transport strategy

This paper examines the evolution of closing the Reynolds-averaged Navier–Stokes equations by approximating the Reynolds stresses via the second-moment transport equations themselves. This strategy first proposed by Rotta is markedly in contrast to the more usual approach of computing an effective “turbulent viscosity” to deduce the turbulent stresses as in a Newtonian fluid in laminar motion. This paper covers the main elements in the development of this approach and shows examples of applications in complex shear flows that collectively include the effects of three-dimensional straining, force fields, and time dependence that affect the flow evolution in ways that cannot be readily mimicked with an eddy viscosity model.

Inbreeding effects in Drosophila congenic strains: the influence of genetic background of different origin

Aim. To compare reproductive indices and stress resistance of Drosophila at outbreeding and inbreeding. Methods. Drosophila melanogaster congenic strains with incomplete development of the radial wing vein – radius incompletus – were used: the laboratory one and the strain, in which the mutation was placed into the genetic background of wild type strain, which originates from the natural population from radiation contaminated territory. Before the experiment strains have passed 65 generations of inbreeding. Viability (number of individuals, pupa stage mortality), dominant lethal mutations frequency and life span of imago at starvation were analysed. Results. After inbreeding, there was a decrease in the frequency of dominant lethal mutations and an increase in viability of the strain, which originates from the natural population, and a decrease of mortality at the pupal stage in both strains. Decreased life span of imago at starvation has been shown only for the inbred strain, which originates from the natural population. Conclusions. Inbreeding for 65 generations has no significant negative effect on reproductive indices; reduction of stress resistance during inbreeding has been shown only for the strain, which originates from the radiation contaminated territory. &#x0D; Keywords: Drosophila, viability, dominant lethal mutations, life span of imago at starvation, inbreeding.

Complete Replacement of Nitrite With a Lactobacillus fermentum on the Quality and Safety of Chinese Fermented Sausages.

This study investigated the positive effects of complete replacement of nitrite with a Lactobacillus fermentum on the quality and safety of Chinese fermented sausages, and evaluated the risk of this strain. The effects of the strain on pH, color, nitrite, thiobarbituric acid reactive substances (TBARS), total volatile basenitrogen (TVB-N), metmyoglobin (Met-Mb), biological amines, free amino acid content, and sensory index have been studied. The results revealed that the strain reduced the pH of the sausages, which reduced the risk of food-borne pathogens, and accelerated the acidification and gelation process. The inoculation of the strain produced pink color similar to 50 mg/kg nitrite, significantly reducing the residual risk of nitrite in the sausages. In addition, the strain effectively improved quality and nutrition of the sausages through preventing fat oxidation, protein decomposition, and myoglobin oxidation and increasing free amino acid content. The harmful biogenic amines species of the treated sample were reduced, although the tyramine contents were higher than the control, and the contents of the two groups were all far below the specified limit (800 mg/kg). The sensory analysis showed that the strain enhanced the taste, flavor, sourness, and overall acceptability of the sample sausages. Therefore, replacing nitrite completely with the strain L. fermentum could be a potential strategy to produce healthier and safer acceptable sausages through decreasing the risk of nitrite and improving nutrition and quality of the sausages.