Effect Of Strain Research Articles

Stacking-dependent structural and electronic properties of trilayer γ-graphyne: An approach for new 2D carbon allotropes.

Vertical stacks of two-dimensional (2D) materials with interlayer van der Waals (vdW) force have provided a versatile approach for creating hybrid materials and modulating various properties. In this work, the structural and electronic properties of trilayer γ-graphyne, involving different stacking patterns, have been investigated through first-principles approaches. The result indicates that a metal-to-semiconducting transition can be triggered simply by switching the stacking order of trilayer γ-graphyne. More interestingly, in addition to typical vdW homostructures, new 2D carbon allotropes with novel carbon networks can be achieved on the basis of trilayer γ-graphyne, arising from the absence of intralayer acetylene linkages during the structural relaxation. One of the new 2D carbon allotropes possesses an intrinsic semiconducting nature with a wide bandgap of 1.827 eV, coupled with superior structural stability beyond single-layer γ-graphyne. Moreover, the biaxial strain effect on the new 2D carbon allotrope, as well as the trilayer vdW stacks, has also been revealed in this work. Correspondingly, the in-plane tensile strain is demonstrated to further enlarge the electronic bandgaps in these carbon sheets. Therefore, the results of this work imply the great potential of few-layer graphyne in future carbon-based nanoelectronic devices, and simultaneously provide a new approach for developing and synthesizing novel 2D carbon allotropes via the vertical stacking of graphyne with inherent acetylene linkages.

Effects of Process Parameters on Microstructure Evolution of Pure Aluminum Target under Clock 135° Collaborative Hot Rolling: A Simulation Study

Based on the results of current research and experiments, clock 135° hot rolling has been widely considered to be the preferred method in target rolling. However, it has been found that the process parameters are of vital importance during the rolling. Therefore, this work focuses mainly on the investigation of the effects of the roll speed ratio and offset distance on the microstructure evolution of a pure aluminum (Al) target under clock 135° collaborative hot rolling. Taking the ultra-thick pure Al metal circular billet as a research object, firstly, the evolutionary behavior of the effective strain (ES) and grain refinement for a rolled piece under the clock counterclockwise 135° synchronous and asynchronous (the speed ratios between rollers are set to be 1:1.05, 1:1.1, 1:1.2, respectively) rolling modes has been comparatively studied based on numerical simulation by DEFORM-3D software. It has been shown that a large ES value of 5.835 mm/mm is obtained in the lower surface layer by counterclockwise 135° asynchronous rolling with a roll–speed ratio of 1:1.2. Meanwhile, the average grain size below 80 µm accounts for ~61.8% of the total grains. These results demonstrate that the clock counterclockwise 135° asynchronous rolling method with a roll speed ratio of 1:1.2 should be an ideal strategy in obtaining finer grains. Unfortunately, nevertheless, the maximum degree of the bad plate shape is generated after forging by clock asynchronous rolling with a speed ratio of 1:1.2. As a consequence, clock counterclockwise 135° snake rolling with a 30 mm offset distance was proposed on the basis of a rolling speed ratio of 1:1.2, which perfectly corrected the warping plate shape caused by clock asynchronous rolling. What is more important, the minimum damage value of 1.60 was achieved accordingly. Meanwhile, the ES value increased in the core of the plate for the clock counterclockwise 135° snake rolling with all of the four offset distances compared to clock synchronous rolling. This study should be significantly conducive to guidance on setting process parameters in the industrial production of hot rolling metal or alloy targets.

Enhanced Regulation of Selectivity by the Coupling Effects of Surface Acidity and Strain Effects via Precisely Controlling the Location of Pt.

Loading a sensitizer and constructing a rational nanostructure have been reported to be effective approaches for enhancing the catalytic/sensing performance. However, the impact of the precise loading position on the catalytic/sensing performance is always overlooked. Here, we discovered that precisely changing the location of Pt clusters from the outside of Al2O3-ZnO nanocoils (O-PtAlZnNCs) to the inner side of the nanocoils (I-PtAlZnNCs) could change the sensing performance of the sensor from H2S to acetone. Furthermore, precisely loading Pt inside of the confined space led to a high sensing performance and reduced the limit of detection (LOD) of acetone by a factor of 50 times (from 100 to 2 ppb). Combining X-ray photoelectron spectroscopy (XPS), NH3-diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), in situ X-ray absorption spectroscopy (XAS), and density functional theory (DFT) simulations, the enhancement of sensitivity and regulation of sensing selectivity are attributed to the coupling effects from enrichment of confined space and Al2O3 acid-base active sites as well as the regulation of electronic structure by location-dominated strain effects. This work not only provides a novel sight to precisely regulate the selectivity and obtain ultrasensitive materials but also serves as a useful instruction for further understanding and precisely designing specific sensors and catalysts with high performance.

Protective Effects of Lactobacillus Strains Against Oxidative Stress and Immune Suppression in Mice Receiving Aflatoxin-Contaminated Diet.

Mycotoxins like aflatoxins pose a significant threat to the health of both people and animals because of their deadly effects. This study aimed to investigate the potential of Lactobacillus strains in reducing the toxicity caused by aflatoxins in mice receiving a diet contaminated with aflatoxins. The mice were split up into various treatment groups, including a control group, an aflatoxin-treated group, and groups treated with the aflatoxin-contaminated diet along with Lactobacillus strains. Various parameters, including liver enzymes, blood parameters, malondialdehyde (MDA) levels, morphometric analysis of ileum, and gene expression, were analyzed to assess the effectiveness of the Lactobacillus strains in mitigating aflatoxins toxicity. Results showed that mice in the aflatoxin-treated group had increased MDA levels, indicating oxidative stress. Alternatively, the Lactobacillus cocktail treatment group showed a decreasing trend in MDA levels, suggesting a reduction in lipid peroxidation. The morphometric analysis of ileum tissue demonstrated that the Lactobacillus-treated group exhibited improved structural integrity compared to the aflatoxin-treated group. Additionally, gene expression analysis revealed that the Lactobacillus treatment attenuated the downregulation of SOD gene expression and mitigated the upregulation of iNOS gene expression induced by aflatoxins. These findings suggest that Lactobacillus strains have the potential to reduce aflatoxin-induced toxicity by alleviating oxidative stress, preserving intestinal tissue integrity, and modulating gene expression associated with antioxidant defense and inflammation. This study provides evidence for the beneficial effects of Lactobacillus strains in reducing aflatoxin toxicity in mice. The findings obtained may contribute to the development of preventive or therapeutic strategies against mycotoxin-induced toxicity.

Cu−based bimetallic sites' p-d orbital hybridization promotes CO asymmetric coupling conversion to C2 products

Hampered by sluggish C−C coupling kinetics, the low selectivity and efficiency have limited industrial applications of CO2 reduction into valuable multi-carbon products. A direct coupling of CO molecules or their coupling after hydrogenation, followed by the final synthesis of C2 products, can help to overcome these limitations potentially. In this study, a detailed high-throughput screening of bimetallic site catalysts comprising copper (Cu) and 28 other metal (M) atoms was conducted. The metal atoms Cu and M were anchored on a carbon nanotube (CNT) with six nitrogen (N6) defects (CuMN6@CNT), which possesses effective dual active sites for C−C coupling. The calculated results demonstrate that the CuGaN6@CNT catalyst exhibited favorable selectivity, with low theoretical overpotentials of −0.23 and −0.34 eV for ethanol and ethylene, respectively, surpassing most reported catalysts. The synergistic effect of Ga and Cu sites, along with their p-d states hybridization, results in an enhancement of Cu's d state dispersion and energy barriers reduction for C−C coupling. Additionally, the strain effect of the substrate CNT exhibits a direct correlation with the catalytic performance of CuGaN6@CNT by adjusting the d-band center of the Cu site and p-band center of the Ga site. These findings provide a novel insights into the electrocatalytic reduction of CO into valuable C2 products using bimetallic single atom catalyst, offering significant guidance for future research endeavors in this field.

The Effect of Lacticaseibacillus rhamnosus, Lacticaseibacillus paracasei, and Bifidobacterium animalis ssp. lactis on the Prevention of Asthma in an Animal Model.

The increase in the prevalence of asthma, particularly in urban communities, has encouraged investigations into preventive strategies. The hygiene theory proposes that early exposure to infections and unhygienic conditions during childhood influences immune system development, potentially protecting against allergic diseases. The mechanisms involved are related to alterations in the intestinal microbiota, such as with probiotics. This study aimed to evaluate the preventive effect of Lacticaseibacillus rhamnosus, Lacticaseibacillus paracasei, and Bifidobacterium animalis ssp. lactis, administered isolated or in combination, at various concentrations, on asthma in an animal model. Mice received two concentrations (1 × 109 and 1 × 1010CFU/ml) of three probiotics, isolated and in combination, over 26 consecutive days, initiating 10days before sensitizing and challenging with ovalbumin. In vivobronchial hyperresponsiveness and airway and lung inflammation were assessed. The administration of L. paracasei, L. rhamnosus, and B. animalis spp. lactis in different concentrations, isolated or in combination, did not reduce hyperresponsiveness and airway and lung inflammation. As probiotic effects are strain and dose-dependents, specific studies are necessary to assess the effect of different probiotic strains, doses, and regimes.

Bending deformation effects on the optoelectronic performance of flexible GaInP/GaAs/InGaAs triple junction solar cells

To achieve genuine carbon neutrality, PV-powered vehicles show promise for future automotive development. However, the impact of curved surfaces on flexible solar cell module performance remains uncertain. This study specifically focuses on newly-designed flexible GaInP/GaAs/InGaAs triple junction solar cells, which have the highest potential output efficiency. A computational model was developed to analyze the electrical performance of curved solar cells, and variations in short-circuit current (Isc) and open-circuit voltage (Voc) with bending angles were determined to closely match experimental data. The effects of incident light intensity, angle, and bending strain on solar cell performance were analyzed to explain the observed Isc and Voc trends. This method can be applied to other III-V group solar cells, providing theoretical support for accurately calculating the performance of curved solar cell modules.

Grain refinement and mechanical properties improvement of additively manufactured Al-Cu alloy through pre-deformation in thermo-mechanical treatment

Inferior mechanical properties induced by porosity and coarse grains of wire-arc additively manufactured Al-Cu alloy restrict its industrial application. The inter-layer cold rolling, conventional heat treatment (T6) and thermo-mechanical heat treatment (T8) was applied to Al-Cu alloy, and the effect of pre-stretched strain in T8 treatment was investigated. The pre-stretched strain induces equal increments of hardness and YS for both the as-deposited and cold-rolled conditions before aging treatment, while the increments for cold-rolled samples are larger after aging treatment. The cold-rolled sample shows better tensile properties than the as-deposited sample with the same pre-stretched strain in T8 treatment, proving that T8 treatment further increased the strengths compared to the T6 treatment. It shows the best tensile properties with the pre-stretched strain of 5 %, exceeding the properties of 2219-T87 plate. With the increased pre-stretched strain, the density of the θ′ phases significantly increases; while further increase to 10 % pre-stretched strain induces severe coarsening of θ′ phases. Therefore, an optimized pre-stretched strain leads to high-density and tiny dispersed θ′ phases, thus resulting in the best tensile properties. Grain refinement induced by inter-layer cold rolling and uniformly precipitated phases resulted from proper pre-stretched strain both contribute to the strengths enhancement. The strengthening mechanism of hybrid additive manufacturing and inter-layer cold rolling followed by T8 treatment was discussed.

Ab initio study of highly tunable charge transfer in β−RuCl3 /graphene heterostructures

Heterostructures of graphene in proximity to magnetic insulators open the possibility to investigate exotic states emerging from the interplay of magnetism, strain and charge transfer between the layers. Recent reports on the growth of self-integrated atomic wires of β−RuCl3 on graphite suggest these materials as versatile candidates to investigate these effects. Here we present detailed first-principles calculations on the charge transfer and electronic structure of β−RuCl3/graphene heterostructures and provide a comparison with the work function analysis of the related honeycomb family members α−RuX3 (X = Cl,Br,I). We find that proximity of the two layers leads to a hole-doped graphene and electron-doped RuX3 in all cases, which is sensitively dependent on the distance between the two layers. Furthermore, strain effects due to lattice mismatch control the magnetization which itself has a strong effect on the charge transfer. Charge accumulation in β−RuCl3 strongly drops away from the chain making such heterostructures suitable candidates for sharp interfacial junctions in graphene-based devices. Published by the American Physical Society 2024

Boosting Acidic Hydrogen Evolution Kinetics Induced by Weak Strain Effect in PdPt Alloy for Proton Exchange Membrane Water Electrolyzers.

Strain engineering is an effective strategy for manipulating the electronic structure of active sites and altering the binding strength toward adsorbates during the hydrogen evolution reaction (HER). However, the effects of weak and strong strain engineering on the HER catalytic activity have not been fully explored. Herein, the core-shell PdPt alloys with two-layer Pt shells (PdPt2L) and multi-layer Pt shells (PdPtML) is constructed, which exhibit distinct lattice strains. Notably, PdPt2L with weak strain effect just requires a low overpotential of 18mV to reach 10mA cm-2 for the HER and shows the superior long-term stability for 510h with negligible activity degradation in 0.5M H2SO4. The intrinsic activity of PdPt2L is 6.2 and 24.5 times higher than that of PdPtML and commercial Pt/C, respectively. Furthermore, PdPt2L||IrO2 exhibits superior activity over Pt/C||IrO2 in proton exchange membrane water electrolyzers and maintains stable operation for 100h at large current density of 500mA cm-2. In situ/operando measurements verify that PdPt2L exhibits lower apparent activation energy and accelerated ad-/desorption kinetics, benefiting from the weak strain effect. Density functional theory calculations also reveal that PdPt2L displays weaker H* adsorption energy compared to PdPtML, favoring for H* desorption and promoting H2 generation.

Local Strain Effects on Lattice Defect Dynamics and Interstitial Dislocation Loop Formation in Irradiated Tungsten-Molybdenum Alloys: A Molecular Dynamics Study.

In this study, molecular dynamics (MD) simulations were used to investigate how alloying tungsten (W) with molybdenum (Mo) and local strain affect the primary defect formation and interstitial dislocation loops (IDLs) in W-Mo alloys. While the number of Frenkel pairs (FPs) in the W-Mo alloy is similar to pure W, it is half that of pure Mo. The W-20% Mo alloy, chosen for further analysis, showed minimal FP variance after collision cascades induced by primary knock-on atoms (PKAs) at 10 to 80 keV. The research examined hydrostatic strains from -1.4% to 1.6%, finding that higher strains correlated with increased FP counts and cluster formation, including IDLs. The following two types of IDLs were identified: majority ½ <111> loops as well as <100> IDLs that formed within the initial picoseconds of the simulations under higher tensile strain (1.6%) and larger PKA energies (80 keV). The strain effects also correlated with changes in threshold displacement energy (TDE), with higher FP formation under tensile strain. This study highlights the impact of strain and alloying on radiation damage, particularly in low-temperature, high-energy environments.

Effects of Stress and Strain on the Optic Nerve Head on the Progression of Glaucoma.

In primary open-angle glaucoma, the rate of retinal nerve fiber layer thickness decrease was negatively correlated with lamina cribrosa strain, which was associated with intraocular pressure and optic nerve head geometric factors. We hypothesized that the biomechanical deformation of the optic nerve head (ONH) contributes to the progression of primary open-angle glaucoma (POAG). This study investigated the biomechanical stress and strain on the ONH in patients with POAG using computer simulations based on finite element analysis (FEA) and analyzed its association with disease progression. We conducted a retrospective analysis that included patients diagnosed with early-to-moderate stage POAG. The strains and stresses on the retinal nerve fiber layer (RNFL) surface, prelaminar region, and lamina cribrosa (LC) were calculated using computer simulations based on FEA. The correlations between the rate of RNFL thickness decrease and biomechanical stress and strain were investigated in both the progression and non-progression groups. The study included 71 and 47 patients in the progression and non-progression groups, respectively. In the progression group, the factors exhibiting negative correlations with the RNFL thickness decrease rate included the maximum and mean strain on the LC. In multivariate analysis, the mean strain on the LC was associated with optic disc radius, optic cup deepening, axial length, and mean intraocular pressure (IOP), whereas the maximum strain was only associated with mean IOP. In early-to-moderate stage POAG, the rate of RNFL thickness decrease was influenced by both the mean and maximum strain on the LC. Strains on the LC were associated with mean IOP, optic disc radius, axial length, and optic cup deepening. These results suggest that not only IOP but also ONH geometric factors are important in the progression of glaucoma.

Effect of human reovirus strain R-92 on tumor cell lines

Background. Among all the new methods and approaches, virotherapy with oncolytic viruses, both in combination with immunotherapy and without it, shows high efficiency in various phases of clinical trials and good tolerance by patients.Aim. To study the sensitivity of some immortalized cancer cell lines to the R-92 strain of human reovirus with cell characteristics at the ultrastructural level.Materials and methods. The study was carried out on cell lines of HeLa, A549, U87MG. Cells were planted in an amount of 15 thousand per well of a 96-well plate and after adhesion, the virus was inoculated by adding a medium containing virus particles in 4 tenfold dilutions (approximately 10 9 –106 particles per ml). Next, the cells were cultured for 24 h, after which the number of living cells in the wells was determined indirectly using the methyl tetrazolium test, which was carried out according to standard methods. To study the ultrastructure of infected cells, cells were seeded into a T25 flask and inoculated with the virus at the maximum concentration. After 24 h of cultivation, the cells were fixed in a 2.5 % glutaraldehyde solution in phosphate buffer for 1 h, after which they were washed three times in phosphate buffer and samples were processed for TEM according to standard methods.Results. Diluting the virus 1000 times led to a decrease in the cytostatic effect in all three cultures to a level practically no different from the control. HeLa turned out to be the most sensitive culture to reovirus. In the experiment, the number of living cells decreased to 60.4 ± 10.2 % compared to the control during incubation with the maximum number of viral particles and to 63.7 ± 16.2 % with a tenfold dilution of the virus. This indicator was significantly lower than in the other two studied cultures under these cultivation conditions (p &lt;0.001).In addition, at the maximum virus concentration, the A549 culture was less sensitive than the U87MG culture (p &lt;0.01). At lower concentrations of viral particles, the average viability of the studied cell lines did not differ significantly from each other. Analysis of electron diffraction patterns showed that the virus successfully replicates in the cytoplasm of the studied cultures, but is not released from the cell, which is apparently due to the short incubation period. TEM also showed cell damage characteristic of apoptosis or necroptosis, uniformly expressed in all studied cultures.Conclusion. Cell lines A549, HeLa and U87MG, according to the results of the methyl tetrazolium test, demonstrate different sensitivity to the human reovirus strain P-92. The TEM picture of cells from infected cultures showed signs of the development of apoptosis or necroptosis.

Improving Catalytic Performance via the Synergy of Tensile Lattice Strain and Plasmonic Enhancement in Defective AuPd@Pd Short Nanowires.

The synthesis of bimetallic nanocatalysts with strained crystal lattices has attracted considerable interest. This is because, beyond the electronic structure modifications realized through elemental doping, the strain effect offers an extra mechanism to fine-tune the electronic structures, thereby possibly improving the catalytic performances. We present a method for constructing defective AuPd@Pd short nanowires, achieved through a controlled galvanic replacement reaction between short AuCu nanowires and Pd precursors. Advanced structural analyses using spherical aberration-corrected transmission electron microscopy (AC-TEM) validated the expanded crystal lattice on the nanowire surface and also demonstrated pronounced plasmonic absorption in the UV-vis region. Leveraging both plasmonic absorption and strain effects, the AuPd@Pd short nanowires displayed a higher apparent rate constant compared to Pd nanoparticles. Integrating molecular dynamic simulations with density functional theory calculations revealed that the tensile strain on AuPd@Pd short nanowires benefited the catalytic activity by elevating the d-band center, thereby intensifying the adsorption of p-nitrophenol. The current research introduces a unique method for synthesizing noble metal nanocrystals with specific dimensions and elucidates the rational development of high-performance plasmonic nanocatalysts through synergistic exploitation of the beneficial strain effect.

Modeling the effects of initial grain size, martensitic transformation induced dynamic grain refinement, phases, and texture on strength of a high entropy alloy using crystal plasticity

Microstructurally flexible high entropy alloys (HEAs) can be tailored for strength via dual-phase strengthening mechanisms, which originate from the strain-induced phase transformation microstructural phenomena. One such alloy is a recently synthesized Fe42Mn28Co10Cr15Si5 (at%) HEA consisting of metastable gamma austenite (γ), stable epsilon martensite (ε), and stable sigma (σ) phases. In this work, a crystal plasticity homogenization incorporating a physically based phase transformation and hardening models is used to interpret and better understand the effects of strain induced phase transformation phenomena on the overall hardening response of the alloy. The transformation model is conceived based on the grain-scale stress sensitive motion of partial dislocations forming shear bands, while the hardening model is an extended Kocks-Mecking-type dislocation density-based formulation sensitive to grain size and shape. The deformation of constituent grains per phase in the alloy is modeled as a combination of anisotropic elasticity, crystallographic glide, and γ→ε phase transformation. Parameters of the hardening and transformation models within the homogenization are calibrated and validated on a suite of data including flow stress curves and phase fractions measured under compression, while the corresponding texture evolution data is used solely for verification. Good predictions of the model elucidate that the transformation induced dynamic Hall-Petch-type barrier effect is the primary origin of strain hardening along with the increase in the ε-phase fraction and dislocation density, while the individual strength of the phases gives rise to the overall strength. The modeling framework described in the present work is expected to be applicable to other HEA systems.

Charge density waves and the effects of uniaxial strain on the electronic structure of 2H-NbSe2

Interplay of superconductivity and density wave orders has been at the forefront of research of correlated electronic phases for a long time. 2H-NbSe2 is considered to be a prototype system for studying this interplay, where the balance between the two orders was proven to be sensitive to band filling and pressure. However, the origin of charge density wave in this material is still unresolved. Here, by using angle-resolved photoemission spectroscopy, we revisit the charge density wave order and study the effects of uniaxial strain on the electronic structure of 2H-NbSe2. Our results indicate previously undetected signatures of charge density waves on the Fermi surface. The application of small amount of uniaxial strain induces substantial changes in the electronic structure and lowers its symmetry. This, and the altered lattice should affect both the charge density wave phase and superconductivity and should be observable in the macroscopic properties.

Strain effect on the electronic and optical characteristics of FAGeX3 (X=Cl, Br, and I) perovskite materials: DFT analysis

This study investigates the electronic and optical properties of a perovskite material known as Formamidinium Germanium Halide (FAGeX3), where X represents the elements Chlorine (Cl), Bromine (Br), and Iodine (I). We explore the bandgap, density of state (DOS), and partial density of state (PDOS) to understand their electronic properties. We use two methods, PBE and HSE-06, to determine the bandgap. Further, we investigate the optical properties by investigating the real and imaginary functions of the dielectric constant, refractive index, electron energy loss function, and absorption coefficient. Our research extends to the impact of biaxial strain, both tensile and compressive, in the −6% to +6 % range. Without strain, the materials exhibit direct bandgaps at the R point, with FAGeCl3 showing the highest bandgap (2.1359 eV), followed by FAGeBr3 (1.7325 eV), and FAGeI3 with the lowest (1.2581 eV). Our results reveal that applying tensile strain increases the bandgap and induces a blueshift, shifting the optical responses to shorter wavelengths, while compressive strain reduces the bandgap and causes a redshift, enhancing longer wavelength responses. Our findings demonstrate that FAGeX3 perovskites exhibit highly tunable electronic and optical properties under strain, making them exceptional candidates for advanced optoelectronic applications.

Growth Promoting Characteristics of Bacillus amyloliquefaciens GZA69 and Its Biocontrol Potential Against Soft Rot of Amorphophallus konjac

Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria colonizing the plant rhizosphere and can promote plant growth. PGPR have important application potential in the field of microbial fertilizers. This study isolated and characterized a PGPR strain GZA69 from konjac rhizosphere soil collected from Damogu Village, Luliang County, Qujing City, Yunnan Province, China. The strain was identified as Bacillus amyloliquefaciens. GZA69 showed diverse plant growth-promoting abilities, including nitrogen fixation, phosphorus solubilization, siderophore production, and indole-3-acetic acid (IAA) production. Tomato was used as an indicator crop to evaluate its growth-promoting effect, two GZA69 suspension concentrations (A1, OD600 = 0.3 and A2, 0.6) were used to treat tomato seeds and seedlings. Plate confrontation assay and konjac corm tissue inoculation were conducted to identify the antagonistic effect of GZA69 strain on the pathogen of konjac soft rot disease. The results showed that, both GZA69 concentrations significantly promoted tomato seed germination (A) and seedling growth, with growth increased of 8.2% and 9.66% in height, 20.87% and 22.77% in root length, and 90% and 130% in fresh weight, respectively. Additionally, GZA69 demonstrated a significant inhibitory effect on the konjac soft rot pathogen, with an inhibition zone of 1.47±0.07 cm. Furthermore, GZA69 effectively reduced disease incidence in inoculated corm tissues, with disease index decreased by 8.00%, 16.23%, 24.80% in co-inoculated with different concentrations of GZA69 suspensions (solution of soft rot pathogen and GZA69 bacterial at ratios of 1:1, 1:2, and 1:3, respectively) comparted to the control (sterile water). In summary, the B. amyloliquefaciens GZA69 screened from konjac rhizosphere soil has various plant growth promoting characteristics and has the potential to prevent and control konjac soft rot disease, which has important application value for developing konjac microbial fertilizers.

Operator-independent assessment of bread spoilage profiles caused by Bacillaceae reveals a high degree of inter- and intraspecies heterogeneity

Ropy bread spoilage caused by aerobic spore-forming bacteria (ASF) is characterized by discoloration, sticky and stringy crumb degradation, and a fruity odor due to the release of volatile organic compounds (VOCs). Previous studies employing model experiments have demonstrated strain-specific spoilage potential. However, to gain a deeper understanding, it is essential to study rope spoilage within baked bread. This study aimed to objectively evaluate the effect of different ASF strains on bread quality. 82 strains were subjected to a comprehensive evaluation, including proteotypic and genotypic fingerprinting, and 13 were selected for further analysis, where ASF endospore-spiked dough samples were baked and incubated. Physical changes in crumb texture, discoloration, and VOC production were quantified using texture analysis, color measurements, and headspace solid-phase microextraction gas chromatography-mass spectrometry. The high intraspecies diversity was reflected in strain-specific variations in rope spoilage profiles. A significant reduction in crumb firmness and increased discoloration, as well as the development of high levels of relative acetoin, were associated with rope spoilage. While color measurements could not detect early-stage spoilage, changes in crumb texture and VOC development were detectable after 24 h of baking. Even low levels of contamination (10^1 spores/g) could cause potential spoilage detectable by texture analysis, although not visible to the naked eye. This study provides an unbiased framework for future research and may help develop early detection tools for improved bread spoilage management.

Effect of bacterial fermentation on the ability of myofibrillar proteins to bind esters and its potential mechanism: Based on protein metabolism and structural changes

The effect of fermentation strains (Lactiplantibacillus plantarum CQ01107 and Staphylococcus simulans CD207) on the binding properties of porcine myofibrillar proteins (MPs) to esters was investigated from two perspectives: metabolism degree and structural alterations. Results demonstrated that S. simulans could reduce the particle size and α-helix content of MPs, while simultaneously increasing the absolute zeta potential and active sulfhydryl content. This process decreased protein aggregation and facilitated the unfolding of MPs, thereby enhancing their binding to esters. Conversely, L. plantarum showed limited promotion, which might be related to its robust acid production and protein hydrolysis capacities. In addition, ethyl octanoate, with a longer carbon chain length, was found to have the highest binding capacity to MPs (28.38 %–41.59 %). Molecular docking results further revealed that the binding of the four esters to MPs was spontaneous, with ethyl octanoate exhibiting the lowest binding energy to MPs (−5.635 kcal/mol). The primary forces involved in the binding of the four selected esters to MPs were hydrophobic interactions, hydrogen bonding, and van der Waals forces. These findings can provide new insights into the mechanisms by which fermentation strains influence flavor formation in fermented foods.