Growth Of LAB Research Articles

Effects of Dioscorea opposita mucilage addition on the physicochemical properties, texture, and stability of set-type yogurt

Dioscorea opposita mucilage (DOM), a polysaccharide-protein polymer with antioxidant activity, can be served as a natural ingredient in nutritional yogurts. The effects of DOM addition at different concentrations (2%, 4%, 6%, 8%, 10% and 12% w/w) on the total number of lactic acid bacteria, pH, titratable acidity, syneresis, viscosity, texture, color and sensory evaluations of full-fat yogurts and skimmed yogurts during 21 days storage at 4 °C were investigated. The results suggested that DOM could improve the growth of LAB, strengthen the network and gelation of yogurt, and thicken the dispersion, which led to the significant decrease in pH and cohesiveness, and drastic increase in the syneresis, firmness and adhesiveness. Additionally, sensory evaluation revealed that the overall liking scores of full-fat yogurts (8.1–8.7) were higher than those of skimmed yogurts (7.9–8.3), which exhibited strong correlations with firmness and viscosity of set-type yogurts. Although DOM addition affected the sensory undesirably, such as creaminess, the thickness and overall liking were improved, especially for the skimmed yogurts. In summary, 8% w/w DOM could effectively improve the texture, quality and stability of set-type yogurts. This study provides new applications in functional dairy products and promotes the value of the by-products of D. opposita.

Strategy to regulate fermentation rate of commercial cut cabbage kimchi by supercooling storage

Kimchi products are often discarded by burst package due to the excessive fermentation during long-term distribution. In this study, supercooling storage was approached to prevent deterioration during distribution by regulating fermentation rate and maintaining quality of products by lowering storage temperature. Herein, cut cabbage kimchi (CCK) products were stored in the supercooling condition by stepwise temperature control algorithm for 12 weeks. During storage, the temperature of CCK was strictly followed the algorithm, maintaining −3.5 °C at the lowest step without ice nucleation. The supercooled CCK were reduced in the LAB growth comparing to the refrigerated CCK, presenting superior quality. Further, heterofermentative LABs were dominant in supercooled CCK after 12 weeks, maintaining the earlier stage of fermentation. Reversely, homofermentative LABs were dominant in refrigerated CCK, meaning the latter stage of fermentation. Freezing suppressed the growth of aerobic bacteria and LAB in CCK and lost the physicochemical qualities by damages from freezing and thawing. Thus, supercooling storage could help maintain the original qualities of CCK to control fermentation rate at −3.5 °C for long-term storage in the static condition. Further studies can be conducted at −3.5 °C reflecting practical conditions.

Replacement of Cheesecloth with Polyamide Plastic Micro-filters in the Manufacturing of Fresh White Boiled Cheese and Pasteurized White Brined Cheese

Cheesecloth used in cheese manufacturing has technical problems; provides low cheese yield and is difficult to clean and disinfect. The present study investigated the effect of substituting cheesecloth with multiple artificial polyamide plastic micro-filters (PPMFs) on the properties of fresh white boiled cheeses (FWBC) and pasteurized white brined cheeses (PWBC) and their whey. Whey was strained by either traditional cheesecloth (control; C) or by one of the PPMFs with different pore sizes (PPMF10, PPMF20, PPMF40, PPMF57 and PPMF 75). The yields of FWBC were 19.46%, 17.13 %, and 14.98% for PPMF10, PPMF20, and PPMF40, respectively. Slightly lower yields were obtained for the PWBC, and the control had the lowest yield (~11.1%). Using PPMFs with increased pore size in both cheeses reduced the total solids, fat, and protein contents. In the whey, reversed trends in the relationship were observed, indicating a loss of solids as fat and protein during the straining. Microbial analysis showed that PPMF cheeses had lower mesophilic aerobes and LAB counts than those of the control. Yeasts, molds, and Staphylococcus aureus were not detected (˂10 log cfu/g) in treatments or the control. In general, FWBC maintained lower microbial counts than PWBC, which was associated with the final boiling step in the FWBC. Cheesecloth maintained the highest microbial counts which would be indicative of the protective effect of cheesecloth on the bacterial cells and their spores. The customary cleaning procedure was not sufficient to eliminate microbial cells from the cheesecloth therefore could represent a source of contamination for cheeses. Acidity (as lactic acid) resulted from the growth of LAB, and PPMFs produced similar or better cheeses in terms of sensory analysis attributes compared to the control.

Enhancing Fertilizer Effect of Bioprocessed Brewers’ Spent Grain by Microbial Consortium Addition

Brewers’ spent grain (BSG) is primarily recycled as livestock feed due to its high fiber content, undegradable protein, and water-soluble vitamins. However, BSG composting represents a possible alternative to organic waste management. Adding a microbial consortium further enhances the agronomical properties of the compost intended for fertilizing applications. Microbial-based fertilizers (plant growth-promoting microorganisms, PGPM) are a means to mitigate the adverse environmental impacts of excessive or improper chemical fertilizer use, enhance the direct or indirect uptake of nutrients by plants, and add value to food waste. In a short-term pot experiment on iceberg lettuce (Lactuca sativa L.), this study assessed the effects of compost and pelletized compost from brewers’ spent grain, both enriched with a microbial consortium. In a randomized block experiment, this study compared four organic BSG fertilizers to chemical fertilizer (NPK) and an unfertilized control treatment. The investigation indicates that BSG compost and BSG pelleted compost, with and without bio-inoculum, in general, are comparable to mineral fertilizer treatment; lettuce fresh weight was higher in pots amended with bioprocessed BSG, associated with more significant growth of soil LAB, fungi, and actinomycetes. The investigation outcomes support composting as an alternative recycling process for producing PGM for agricultural applications.

Combined Effect of Acid Whey Addition and Ultrasonic Treatment on the Chemical and Microbiological Stability of Lamb Stuffing.

The microbiological and chemical stability of stuffing is crucial in meat processing. Small ruminant (lamb) meat has many nutritional advantages (fatty acid composition and ratio, high biological value of protein, source of zinc, and selenium) but is poorly utilized in processing. In this experiment, we determined the effects of physical (sonication), chemical (salt, curing salt, and air access), and microbiological (acid whey) factors on the microbiological and chemical stability of lamb meat stuffing. Proximate composition and fatty acids profile, pH, water activity, lipid oxidation, color parameters, and microbiology examinations were performed in fresh meat stuffing and on the fifth day of refrigerated storage. Ultrasound treatment of the meat with whey reduced its acidity and increased the oxidative stability of fats but did not modify the water activity and color of the stuffing. Stuffing sonication did not affect the growth of LAB but reduced the number of Entereobacteriace, especially in the presence of whey and salt. The treatment of lamb meat stuffing with low-frequency and medium-intensity ultrasound assisted by the addition of acid whey and salt is a technique conducive to reducing the use of nitrates in meat technology and their consumption by consumers.

Valorization of palm tree (Phoenix dactylifera L.) leaves from harsh weather climate by silage using endogenous lactic acid bacteria, and application of MALDI-TOF MS for study of populations dynamics

Preservation of green palm leaves by silage preserves them as green feed in addition to the added value of probiotics and prebiotics. In this work, the characterization of fresh palm tree leaves was performed. The isolation of local lactic acid bacteria allowed selection of 4 isolates for the silage of the palm tree leaves. Dairy feed was used to enrich the leaves silage with the necessary nutrients. Lactobacillus paracasei and Pediococcus acidilactici were found to be dominating their respectively inoculated silages. The high occurrence of LAB found in the spontaneous silages of the palm tree leaves mixed with dairy feed is a good indication that ensiling palm tree leaves can support the growth of LAB and produce good-quality silage. However, a combination of the process by following the population dynamics using MALDI-TOF MS allowed the selection of the appropriate LAB strain, which is a new approach for application of silage.

Cilia Stimulatory and Antibacterial Activities of T2R Bitter Taste Receptor Agonist Diphenhydramine: Insights into Repurposing Bitter Drugs for Nasal Infections.

T2R bitter taste receptors in airway motile cilia increase ciliary beat frequency (CBF) and nitric oxide (NO) production. Polymorphisms in some T2Rs are linked to disease outcomes in chronic rhinosinusitis (CRS) and cystic fibrosis (CF). We examined the expression of cilia T2Rs during the differentiation of human nasal epithelial cells grown at air–liquid interface (ALI). The T2R expression increased with differentiation but did not vary between CF and non-CF cultures. Treatment with Pseudomonas aeruginosa flagellin decreased the expression of diphenhydramine-responsive T2R14 and 40, among others. Diphenhydramine increased both NO production, measured by fluorescent dye DAF-FM, and CBF, measured via high-speed imaging. Increases in CBF were disrupted after flagellin treatment. Diphenhydramine impaired the growth of lab and clinical strains of P. aeruginosa, a major pathogen in CF and CF-related CRS. Diphenhydramine impaired biofilm formation of P. aeruginosa, measured via crystal violet staining, as well as the surface attachment of P. aeruginosa to CF airway epithelial cells, measured using colony-forming unit counting. Because the T2R agonist diphenhydramine increases NO production and CBF while also decreasing bacterial growth and biofilm production, diphenhydramine-derived compounds may have potential clinical usefulness in CF-related CRS as a topical therapy. However, utilizing T2R agonists as therapeutics within the context of P. aeruginosa infection may require co-treatment with anti-inflammatories to enhance T2R expression.

Glutamate in the medium of Lactiplantibacillus plantarum FL-664 affects the production of IL-12(p40) on murine spleen cells.

Lactic acid bacteria (LAB) have been attracting attention for their effects on innate immunity, and therefore, it is required to develop an efficient culturing method while maintaining their functionality. In this study, first, we compared the growth and functionality of LAB cultured on food grade (FG) medium with those on standard LAB medium and found that LAB cultured in the FG medium were smaller in cell size with high yield and had a higher ability to induce IL-12(p40) production by murine spleen cells in vitro. Moreover, the higher the glutamate concentration in the medium, the smaller the cell size, and the higher the yield and the higher the ability to induce IL-12 production. Addition of glutamate to the culture medium changes the size of LAB and affects their ability to induce IL-12(p40) production. In conclusion, regulating the concentration of glutamate would be important in the efficient culturing of functional LAB.

In vitro Effects of Prebiotics and Synbiotics on Apis cerana Gut Microbiota.

This study aimed to investigate in vitro effects of the selected prebiotics alone, and in combination with two potential probiotic Lactobacillus strains on the microbial composition of Apis cerana gut microbiota and acid production. Four prebiotics, inulin, fructo-oligosaccharides, xylo-oligosaccharides, and isomalto-oligosaccharides were chosen, and glucose served as the carbon source. Supplementation of this four prebiotics increased numbers of Bifidobacterium and lactic acid bacteria while decreasing the pH value of in vitro fermentation broth inoculated with A. cerana gut microbiota compared to glucose. Then, two potential probiotics derived from A. cerana gut at different dosages, Lactobacillus helveticus KM7 and Limosilactobacillus reuteri LP4 were added with isomalto-oligosaccharides in fermentation broth inoculated with A. cerana gut microbiota, respectively. The most pronounced impact was observed with isomalto-oligosaccharides. Compared to isomalto-oligosaccharides alone, the combination of isomalto-oligosaccharides with both lactobacilli strains induced the growth of Bifidobacterium, LAB, and total bacteria and reduced the proliferation of Enterococcus and fungi. Consistent with these results, the altered metabolic activity was observed as lowered pH in in vitro culture of gut microbiota supplemented with isomalto-oligosaccharides and lactobacilli strains. The symbiotic impact varied with the types and concentration of Lactobacillus strains and fermentation time. The more effective ability was observed with IMO combined with L. helveticus KM7. These results suggested that isomalto-oligosaccharides could be a potential prebiotic and symbiotic with certain lactobacilli strains on A. cerana gut microbiota.

Shelf-life extension of vacuum packed emulsion-type sausage using combination of natural antimicrobials

The aim of the present study was to investigate the effect of natural antimicrobials: nisin, cinnamon essential oil (CEO), ethylenediaminetetraacetate (EDTA) and their combinations, on the shelf-life of emulsion-type cooked cured sausage stored under vacuum packaging, at 10 °C for a period of 42 days. The treatments of emulsion-type sausage were as the following: nisin 10 mg/kg (N), cinnamon essential oil 500 mg/kg (C), EDTA 300 mg/kg (E), nisin 10 mg/kg + cinnamon essential oil 500 mg/kg (N + C), EDTA 300 mg/kg + cinnamon essential oil 500 mg/kg (E + C), nisin 10 mg/kg + EDTA 300 mg/kg + cinnamon essential oil 500 mg/kg (N + E + C) and finally control (non-treated) sample. All samples were examined at days 1, 14, 28, 35 and 42 of storage for total count, LAB count, pH, sensory characteristics and objective color. The results showed that nisin and CEO treatments, increased sausages shelf life for 14 and 7 days respectively, whereas N + C and N + E + C treatments were not effective to extend shelf-life more than 7 and 14 days respectively, compared to the control samples. Although the EDTA alone was ineffective in inhibiting growth of LAB and total bacteria, shelf-life of the sausages treated with E + C and N + E were extended from 14 (control samples) to 35 days. This study indicated that combinations of natural antimicrobials were significantly effective on extension of product shelf-life.

A dry film technology for the manufacturing of 3-D multi-layered microstructures and buried channels for lab-on-chip

The development of innovative and reliable techniques for devices miniaturization are enabling the massive growth of lab on chip (LOC) applications. In this article, we briefly review the technological options for LOC microfabrication, then we present the optimization of a process for the realization of tridimensional multi-layered structures and buried channels in a microfluidic network using a photo-patternable dry film, with a potential for LOC manufacturing. The tuning of all the fabrication parameters is widely discussed and micrographs and optical profiler images are reported to show fabrication results. The fabrication process is used for a Split-flow-thin (SPLITT) fractionation cell configuration. SPLITT is a particle fractionation technique based on the combined effect of two laminar streams (the sample containing the particles and a carrier) flowing inside a thin microchannel and the action of a vertical driving force for particle displacement. Since the SPLITT implemented in this work is electrically driven, patterned electrodes (thickness: 100 nm) are also integrated in the flow cell walls. The functionality of the cell was tested first verifying the presence of proper flow conditions for microfluidic SPLITT (absence of mixing between the streams) and then proving electrical fractionation with two different proteins (BSA and β-lactoglobulin) at different levels of ionic strength. The flow of the streams within the microfluidic channel was also simulated by a numerical 2-D model exactly reproducing the cell geometry, with a good accordance with experimental results.

Microbiota of sliced cooked ham packaged in modified atmosphere throughout the shelf life: Microbiota of sliced cooked ham in MAP

Fourteen lots of cooked ham in modified atmosphere packaging (CH) were analyzed within a few days from packaging (S) and at the end of the shelf-life (E), after storage at 7 °C to simulate thermal abuse. Five more lots, rejected from the market because spoiled (R), were included in the study. Quality of the products was generally compromised during the shelf life, with only 4 lots remaining unaltered. Analysis of 16S rRNA gene amplicons resulted in 801 OTUs. S samples presented a higher diversity than E and R ones. At the beginning of the shelf life, Proteobacteria and Firmicutes dominated the microbiota, with Acinetobacter, Brochothrix, Carnobacterium, Lactobacillus, Prevotella, Pseudomonas, Psychrobacter, Weissella, Vibrio rumoiensis occurring frequently and/or abundantly.E and R samples were dominated by Firmicutes mostly ascribed to Lactobacillales. It is noteworthy the appearance of abundant Leuconostoc, negligible in S samples, in some E and R samples, while in other LAB were outnumbered by V. rumoiensis or Brochothrix thermosphacta. The microbiota of spoiled and R samples could not be clustered on the basis of specific defects (discoloration, presence of slime, sourness, and swollen packages) or supplemented additives. LAB population of S samples, averaging 2.9 log10(cfu/g), increased to 7.7 log10(cfu/g) in the E and R samples. Dominant cultivable LAB belonged to the species Lactobacillus sakei and Leuconostoc carnosum. The same biotypes ascribed to different species where often found in the corresponding S and R samples, and sometime in different batches provided from the same producer, suggesting a recurrent contamination from the plant of production. Consistently with growth of LAB, initial pH (6.26) dropped to 5.74 in E samples. Volatiles organic compound (VOCs) analysis revealed that ethanol was the major metabolite produced during the shelf life. The profile of volatile compounds got enriched with other molecules (e.g. 2-butanone, ethyl acetate, acetic acid, acetoin, butanoic acid, ethyl ester, butanoic acid, and 2,3-butanediol) mainly ascribed to microbial metabolism.

Coadministration of ginger extract-Lactobacillus acidophilus (cobiotic) reduces gut inflammation and oxidative stress via downregulation of COX-2, i-NOS, and c-Myc.

Aim of the study was to evaluate a combination of ginger extract (GE; antioxidant, anti-inflammatory) and Lactobacillus acidophilus (LAB; probiotic), in DMH-DSS-induced inflammation-driven colon cancer, in Wistar rats. Effect of varying GE concentration on growth of LAB was assessed in vitro. Colonic histology and permeability, oxidative stress, serum proinflammatory cytokines, expression of selected genes, gut bacteria, and SCFA determination of gut content was monitored after treatment with agents alone or in combination, postdisease induction. Significant increase in LAB CFU was observed following 48 and 96hr of incubation with GE; 0.4% w/v GE showed the best results and was used in the cobiotic. Cobiotic administration significantly reversed the DMH-DSS-induced colonic histological alterations. Significant (p<.05) reduction in lipid peroxidation and increase in antioxidant levels (catalase and SOD) was observed in cobiotic group, whereas individual agents did not show any effect. Restoration of colonic permeability, decrease in serum inflammatory burden, and downregulation of COX-2, iNOS, and c-Myc expression on treatment with cobiotic was significantly (p<.05) better than individual agents. Neither LAB nor cobiotic administration produced any change in gut bacteria nor SCFA levels, probably due to loss of LAB viability under adverse gut conditions. Study concludes that presented cobiotic has a promising therapeutic potential, which can be improved by a smartly designed formulation.

Isolat Bakteri Asam Laktat Sebagai Probiotik dengan Vaksinasi AI dan ND dalam Pembentukan Titer Antibodi Dan Bobot Badan Ayam Jantan Tipe Medium

Isolates of Lactic Acid Bacteria isolates assembled into a mixture of LAB as probiotics . LAB probiotic drops introduced through the mouth with the aim of suppressing pathogens and is expected to improve the health status of rooster type of medium . Isolates in the digestive tract will undergo adaptation by temperature , acidity and pH changes in the gut . The health status of the chicken can be expressed as growth to form the body weight , and the growth of LAB . In addition , AI and ND vaccination in healthy chickens conditions will produce antibodies to both . The success of vaccination can be evaluated from the results of the formation of chicken blood serum titre of research . Analysis of descriptive data on the dynamics of the growth of LAB , the formation of antibody titer and body weight gain 24-31 day old chickens . Based on the results of this study revealed that isolates of LAB can be used simultaneously in bercoccidiostat feed . LAB isolates may develop in the digestive tract rooster medium type as probiotics. The dynamics of the growth of a population produces a mixture of isolates of LAB isolates (mixture of B1, B3, B4, B5 as probiotics) in the highest reaches of the ilium and jejunum 14.00 x 10-6 13.5 x 10-6 CFU/ml. Test isolates viability of probiotic candidates in all isolates produced distilled water medium can live up to 72 hours of incubation . In addition, there is a synergy results in the formation of antibody titers ND uniform T3 treatment. T3 treatment is given probiotics 2x chicken every week for 3 weeks . In AI vaccination resulted in antibody titers are not uniform. Body weight gain reached the age of 24-31 days in a row 75.83 g, 76.54 g, 81.58 g, 87.04 g. Weight age of 31 days the average value obtained successively from the highest 329.16 g, 328.54 g, 325.54 g and 324.08 g lowest . Keywords; isolates LAB, probiotics, antibody titers, rooster layer medium type.

Effect of Fruit Pectin on Growth of Lactic Acid Bacteria

The concept of modulating gut health through diet is not new and dates back to at least the beginning of the 20th century. However, it is only recently that sound scientific rationales have been proposed and investigated. Three microflora modulation tools have emerged, the addition of exogenous living microorganisms to foods (i.e., probiotics), the selective stimulation of the growth and activity of beneficial microorganisms indigenous to the gut (i.e., prebiotics), and a combination of both approaches (i.e., synbiotics). Fruit wastes which are highly perishable and seasonal, is a problem to the processing industries and pollution monitoring agencies. A valuable byproduct that can be obtained from fruit wastes is pectin. An effort was taken to extract pectin from different fruit waste (Musa sp. and Citrus limetta and rind of Citrullus lanatus and putrefied fruits of Solanum lycopersicum and Psidium guajava). An attempt was made to observe the enhancement of growth of Lactic Acid Bacteria (LAB-Lactobacillus casei, L. acidophilus, Bifidobacterium bifidum) by introducing the pectin samples from the above fruit waste. It was observed that pectin was able to enhance the growth of the bacteria and the titrable acidity considerably. Hence it can be concluded that pectin that is extracted from fruit waste can be used to enhance the growth of LAB. The current study aims to prove pectin as a potential prebiotic.

Nutritional, chemical and microbiological changes during fermentation of tarhana formulated with different flours.

BackgroundTarhana is a fermented cereal product that is used for the preparation of one of the favourite soups in Turkish cuisine. Tarhana is a mixture of wheat flour, yoghurt, baker’s yeast, salt, and various vegetables, spices and seasonings. It is obtained by mixing all ingredients in the recipe and afterwards the mixture is let to ferment at room temperature. Following fermentation tarhana is dried or frozen for long term storage. In this study, to improve the nutritional benefits of tarhana, whole wheat and chickpea flours were used as the sole source of flour. The changes in the phytic acid content, proteins and fermentation products were investigated in addition to some microbiological and chemical characteristics.ResultsThe effect of flour type on the phytic acid content was significant. No differences were observed in the glutenin band patterns of the wheat and whole wheat flours and their tarhana samples. Conversely, for the gliadin fractions, the bands of the wheat and whole wheat flours were more intense than their tarhana samples. The changes in the glutelin and prolamin fractions of the chickpea flour and the resultant tarhana dough were similar to the glutenin and gliadin fractions of wheat and whole wheat flours and their tarhana samples. In all samples, the yeasts displayed an undulant growth pattern and the effect of flour type and fermentation time on yeast growth was significant (P < 0.01). The effect of flour type (P < 0.01) and fermentation time (P < 0.05) on mesophilic LAB was significant. Similar behaviours were observed with the mesophilic LAB in all samples and their numbers remained closed to their initial numbers. The growth of thermophilic LAB was not influenced by the flour type, but the effect of fermentation time was significant (P < 0.01).ConclusionsThe whole wheat and chickpea tarhana are found to be good alternatives to classical tarhana with their higher nutritional benefits but further investigations are needed for the assessment of their sensory properties.

Growth and design of LaB6microcrystals by aluminum melt reaction method

In this work, lanthanum hexaboride (LaB6) microcrystals were prepared by using the aluminum melt reaction method. The morphology evolution of LaB6 microcrystals was investigated by field-emission scanning electron microscopy (FESEM), and its growth mechanism was also discussed. As {111} planes have the highest growth rate, LaB6 crystals tend to form “perfect cubes” (equilibrium crystal morphology) with minimum total surface free energy. In Al melt with 3% of LaB6, the intrinsic preferential growth dominates and LaB6 microcrystals eventually grow into the “perfect cubes”, through a series of intermediate products, including “octa-pods” and “imperfect cubes”. By adjusting the concentration of reactants, polyhedral and dendritic LaB6 microcrystals were designed and prepared. The formation of these two non-equilibrium crystal morphologies is caused by a reduced growth rate of the preferential growth direction and the effect of constitution undercooling, respectively. Furthermore, the effect of LaB6 on the high temperature tensile strength of Al–Si alloy was also studied.

Growth of a Simulation Lab: Engaging the Learner Is Key to Success

igh-fidelity simulation (HFS) is an important adjunct to clinical training for eaching health care workers. Currently, the American College of Surgeons as created a multilevel certification for surgical simulation centers. The merican Society of Anesthesiologists Workgroup on Simulation Education as begun to characterize simulation centers for the purposes of “approval” s a site to provide continuing medical education credits. The Accreditation ouncil for Graduate Medical Education Residency Review Committee for mergency Medicine has determined that simulation may serve as an adjunct or the documentation of competencies. The Society for Academic Emerency Medicine’s Simulation Academy has recently made recommendations or accreditation and programmatic benchmarks for emergency medicine imulation. Since 2006, HFS has become increasingly integrated into ndergraduate and graduate medical educational curricula. The primary benefit of using HFS is that learners can practice medical ecision-making and procedures skills on simulated patients in an environent where the risk of error will not harm an actual patient. These echnologies were developed to practice skills without incurring risk: in the ilitary for war games exercises, in the aerospace industry for flight training f pilots and astronauts, and in the nuclear power industry to train personnel. ridging the gap between other industries and medicine, Gaba and DeAnda ioneered the use of simulation in anesthesia to train anesthesiologists. Simulation has also received favorable reviews as an effective model for eaching medicine because of its ability to allow learners of all levels to

Optimum conditions for combined application of Leuconostoc sp. and Saccharomyces sp. to sourdough

Investigation of the optimum conditions for the combined application of Saccharomyces sp. (yeast) and Leuconostoc sp. (lactic acid bacteria, LAB) isolated in a previous study to the development of novel sourdough was carried out by response surface analysis. First, the cell growth conditions were analyzed. LAB showed good proliferation under conditions of 30–35°C, low pH, and high acidity, whereas the growth of yeast was inhibited. The growth of yeast was optimum at 25°C for 24 h. Based on these results, analysis of sourdough was carried out by varying the LAB population, temperature, and time after fixing the number of yeast. It was determined by response surface analysis that the optimal conditions for fermentation are LAB population of 105 CFU/mL, temperature of 25°C, and reaction time of 24 h. From these results, the growth of LAB should be constantly maintained, and an appropriate pH that does not inhibit the growth of yeast due to the presence of generated organic acid is required to allow for the unique properties of sourdough. This study could give useful information for the development of novel sourdough.

Buffer-layer-enhanced growth of a single-domain LaB 6 (1 0 0) epitaxial thin film on a MgO (1 0 0) substrate via pulsed laser deposition

Epitaxial growth of LaB 6 (1 0 0) thin films was examined on MgO (1 0 0) and sapphire (α-Al 2O 3) (0 0 0 1) substrates with insertion of a 2–3 nm-thick epitaxial SrB 6 buffer layer by pulsed laser deposition in ultra-high vacuum. Reflection high-energy electron diffraction, X-ray diffraction, and the Raman scattering spectroscopy measurements proved that the heteroepitaxial structure of the LaB 6 (1 0 0)/SrB 6 (1 0 0)/MgO (1 0 0) substrate has a single-domain, while and that of the LaB 6 (1 0 0)/SrB 6 (1 0 0)/sapphire (0 0 0 1) substrate have three domains. LaB 6 thin films grown without the buffer layer were not epitaxial; instead, they developed as polycrystalline films with a random in-plane configuration. The buffer layer greatly affected the initial growth of the LaB 6 thin films. Epitaxial LaB 6 thin films exhibited metallic behavior with almost constant resistivities in the temperature range 12–300 K. At room temperature, the resistivities of single-domain LaB 6 (1 0 0) epitaxial thin films on MgO substrates were about 5 times smaller than those of the three-domain LaB 6 (1 0 0) epitaxial thin films on the sapphire substrates.