Nutrient L-Alanine-Induced Germination of Bacillus Improves Proliferation of Spores and Exerts Probiotic Effects in vitro and in vivo

As alternatives to antibiotics in feed, probiotic Bacillus carries multiple advantages in animal production. Spores undergo strain-related germination in the gastrointestinal tract, but it is still unknown whether the probiotic function of the Bacillus depends on the germination of spores in vivo. In this study, based on 14 potential probiotic Bacillus strains from fermented food and feed, we detected the germination response of these Bacillus spores in relation to different germinating agents. The results showed the germination response was strain-specific and germinant-related, and nutrient germinant L-alanine significantly promoted the growth of strains with germination potential. Two strains of Bacillus subtilis, S-2 and 312, with or without a high spore germination response to L-alanine, were selected to study their morphological and genic differences induced by L-alanine through transmission electron microscopy and comparative transcriptomics analysis. Consequently, after L-alanine treatment, the gray phase was largely increased under microscopy, and the expression of the germination response genes was significantly up-regulated in the B. subtilis S-2 spores compared to the B. subtilis 312 spores (p < 0.05). The protective effect of L-alanine-induced spore germination of the two strains was comparatively investigated both in the IPEC-J2 cell model and a Sprague–Dawley (SD) rat model challenged by enterotoxigenic Escherichia coli K99. The result indicated that L-alanine helped B. subtilis S-2 spores, but not 312 spores, to decrease inflammatory factors (IL-6, IL-8, IL-1 β, TNF-α; p < 0.05) and promote the expression of occludin in IPEC-J2 cells. Besides, supplement with L-alanine-treated B. subtilis S-2 spores significantly improved the growth of the SD rats, alleviated histopathological GIT lesions, and improved the ratio of jejunal villus length to crypt depth in comparison to the B. subtilis S-2 spores alone (p < 0.05). Improved species diversity and abundance of fecal microbiota were only observed in the group with L-alanine-treated S-2 spores (p < 0.05). The study demonstrates L-alanine works well as a probiotic Bacillus adjuvant in improving intestinal health, and it also provides a solution for the practical and accurate regulation of their use as antibiotic alternatives in animal production.

Firefighter Observations of “Surprising” Fire Behavior in Mountain Pine Beetle-Attacked Lodgepole Pine Forests

The recent mountain pine beetle outbreak affecting lodgepole pine forests in the Rocky Mountains has created a novel fire environment for wildland firefighters. This paper presents results from an examination of firefighters’ observations of fire behavior in post-outbreak lodgepole pine forests, with a focus on what they considered surprising from a fire behavior standpoint and how this in turn affected their suppression tactics. The surprises in fire behavior experienced by firefighters during the red phase of post-outbreak forests included an elevated level of fire spread and intensity under moderate weather and fuel moisture conditions, increased spotting, and faster surface-to-crown fire transitions with limited or no ladder fuels. Unexpectedly, during the gray phase in mountain pine beetle-attacked stands, crown ignition and crown fire propagation was observed for short periods of time. Firefighters are now more likely to expect to see active fire behavior in nearly all fire weather and fuel moisture conditions, not just under critically dry and windy situations, and across all mountain pine beetle attack phases, not just the red phase. Firefighters changed their suppression tactics by adopting indirect methods due to the potential fire behavior and tree-fall hazards associated with mountain pine beetle-attacked lodgepole pine forests.

Rare Earth Metal-Based Intermetallics Formation in Al–Cu–Mg and Al–Si–Cu–Mg Alloys: A Metallographic Study

This study was conducted on Al–Cu–Mg and Al–Si–Cu–Mg alloys containing either 5%La or 5%Ce. Two levels of Ti addition were examined, i.e., 0.05% and 0.15%. Thermal analysis was the only technique used to obtain castings, from which samples were then sectioned for metallographic examination. Based on the results obtained, the following points may be highlighted. Addition of a fairly large amount of RE metals (La or Ce) leads to the appearance of several peaks in the solidification curve between the precipitation of the primary α-Al phase and the (Al–Al2Cu) eutectic reaction. Although a significant drop in the eutectic temperature is caused by the addition of 5%La or Ce, the corresponding modification of the eutectic Si is marginal. Two main types of intermetallics were documented: a gray phase in the form of sludge with a fixed composition and a white phase in the shape of thin platelets. Due to the high affinity of RE to react with Si, Fe, and Cu, several compositions were obtained explaining the observed multiple peaks in the solidification curve. Judging by the morphology of the gray phase, it is assumed that this phase is precipitated in the liquid state and acts as a nucleation site for the white phase. Lanthanum and Ce can substitute each other.

Effects of Co on the Solidification and Precipitation Behaviors of IN 718 Alloy

The effects of Co from 0 to 11.60 % (in mass fraction) on the solidification and precipitation behaviors of IN 718 alloy had been investigated. The results showed that the volume fraction of the dendrite core increased with the addition of Co. In the alloys with 0-5.84 %Co, the addition of Co could restrain the precipitation of blocky Laves phase and promoted the formation of eutectic Laves phase. In the alloys with 9.00-11.60 % Co, the eutectic gray phase and small blocky Laves phase precipitated in the interdendritic region. The eutectic gray phase increased and small blocky Laves phase decreased with increasing Co. The parallel lath-like δ-Ni3Nb phase was observed to precipitate in some interdendritic region without the formation of gray phase and Laves phase in the 9.00-11.60 % Co alloys. Further research found that Co slightly segregated in the dendrite core and markedly raised the solubility of element Mo in the dendrite core which resulted in reduced Mo in the residual liquid, and consequently, restrained Laves phase while promoted the precipitation of Mo-depleted gray phase and δ-Ni3Nb phase. Furthermore, Co was seemed to elevate the solidification point of the γ matrix while decrease that of the Laves phase.

Microstructure and Compound Developed from the Ce-As-Fe at 1173K

In this study, a certain amount of Cerium and Arsenic were closed in the barrel-shaped cylinder machined by H08 steel, heated to 1173 K for 50 h, and the interaction among the cerium, arsenic and iron in the barrel-shaped cylinder was studied by X-ray diffraction, optical microscopy and electronic probe microscopy analysis. The result shows that the gray phase is the ternary compound Ce12Fe57.5As41, and the ternary compound Ce12Fe57.5As41 is the main interaction product when the atomic ratio of Ce to As is 1:3. The eutectic compound Fe2As can be precipitated from ferrite with the temperature decreasing.

Microstructure and Compound Developed from La-As-Fe System at 1223K

The interaction among Lanthanum, Arsenic and Iron at 1223K were studied by means of electron probe microanalysis, optical microscopy and X-ray diffraction. The result shows that the gray phase might be a ternary compound La10Fe50As40, and the binary compound LaAs and the ternary compound La10Fe50As40 are the main interaction products when the atomic ratio of La to As is 1:3. The eutectic compound Fe2As can be precipitated from ferrite with the temperature decreasing.

Study on Interaction among Cerium-Arsenic-Iron

The interaction in the Cerium-Arsenic-Iron system at high temperature were studied by means of electron probe microanalysis, optical microscopy and X-ray diffraction. The results show that the CeAs is the main product when the atomic ratio of Cerium to Arsenic is 1:2, and a light gray phase in bright field might be a ternary compound Ce12Fe57.5As41. The diffusion coefficient of Arsenic in iron was calculated as 1.606×10-13m2/S.

Study on Interaction between Cerium and Arsenic

The interaction among Cerium, Arsenic and Iron at high temperature were studied by means of electron probe microanalysis, optical microscopy and X-ray diffraction. The result shows that the binary compound CeAs is the main interaction product when the atomic ratio of Ce to As is 1:2. The eutectic compound Fe2As can be precipitated from ferrite with the temperature decreasing, and the gray phase in bright field might be a ternary compound Ce12Fe57.5As41.

Orientation Imaging of A Nb-Ti-Si Directionally Solidified In-Situ Composite

In this paper we report on the microstructural characterization of a directionally solidified (DS) Nb-Ti-Si alloy. The solidified ingot had a nominal composition of Nb-33 at%Ti-16 at% Si and was grown using the Czochralski technique with growth rate of 5 mm/min. The as-solidified ingot was approximately 50 mm long with a 10 mm diameter. The microstructure was examined using backscatter electron imaging and the microtexture of each of the phases was determined using the Electron BackScattering Pattern (EBSP) technique for electron diffraction in the scanning electron microscope. The details of the experiments are similar to those we have reported previously. Automated EBSP scans were acquired in order to map the local texture (microtexture) over most of a transverse cross-section through the ingot.Figure 1 is a backscattered electron image (BEI) of a transverse section of the as-solidified microstructure. In this image, the bcc-Nb phase is the lighter gray phase and has a dendritic structure. The dark gray phase is (Nb,Ti)3Si having a Ti3P crystal structure. The silicide phase appears as both multiply-faceted dendrites and irregularly bounded grains. A pattern of shading, due to Ti segregation, can be seen in figure 1 and suggests a cellular solidification structure. Figure 2 is a BEI taken at higher magnification to show a region that was analyzed by automated-EBSP. Figure 3 contains orientation images generated from the automated-EBSP data set. In Figure 3a, the color black signifies positions for which no Nb diffraction patterns could be indexed and other shades of gray signify specific Nb orientations, as described by a set of Euler angles. A similarly generated orientation image for the silicide phase is shown in Figure 3b. The greyscale image presented here is actually a rendering of a truecolor image based on a RGB triplet using the Euler angles.