La Content Research Articles

The Global Regulator CcpA of Listeria monocytogenes Confers Sensitivity to Antimicrobial Fatty Acids.

Free fatty acids (FFAs) are known to exhibit antimicrobial and anti-virulent properties against bacterial pathogens. Specific FFAs, such as lauric acid (LA; C12:0), exert both effects against the foodborne pathogen Listeria monocytogenes: at low levels, LA acts to inhibit the activity of the virulence regulator PrfA, whereas at higher levels, LA inhibits bacterial growth. Deletion of prfA is known to promote tolerance toward antimicrobial FFAs, suggesting that the response of L. monocytogenes to anti-virulent and antimicrobial FFAs could be linked. In this study, we explored the response of L. monocytogenes toward antimicrobial FFAs holding an anti-virulence activity by isolating strains that can grow at high concentrations of LA. We found that LA-tolerant isolates carry mutations in the gene encoding the global regulator CcpA. Importantly, we discovered that mutation or deletion of ccpA protect L. monocytogenes against the antimicrobial activity of FFAs, whereas the ccpA mutants remain sensitive toward FFA’s PrfA inhibitory effect. A regulatory link involving CcpA, connecting the response toward the antimicrobial and anti-virulence activities of FFAs, is therefore unlikely. To further study how deletion of ccpA promotes FFA tolerance, we performed a transcriptomic analysis of the response to LA. Our data indicated that the FFA-tolerant phenotype of the ∆ccpA strain is not induced upon LA exposure but appears to be an inherent phenotypic trait of the ccpA deletion mutation. Interestingly, we found that the bacterial surface of L. monocytogenes becomes more hydrophilic upon deletion of ccpA, and we demonstrate that CcpA plays a role in the response of L. monocytogenes to other stress conditions, including low pH and antibiotics. Altogether, our study revealed that regulatory activities of CcpA lead to an increased hydrophobicity of the bacterial surface, which may confer sensitivity of L. monocytogenes against the antimicrobial activity of FFAs. Notably, CcpA is not involved in responding to the PrfA inhibitory effect of FFAs, showing that FFA-tolerant strains can still be targeted by the anti-virulent activity of FFAs.

Nanostructure evolution, thermal stability and hardness of amorphous Al–Cu-Y (Co, La) (at.%) alloys

Al alloys with nominal composition of Al86Cu6Y6Co2, Al86Cu6Y6La2 and Al84Cu6Co2Y6La2 (at.%) were studied in as- spun and annealed states using differential scanning calorimetry (DSC), field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) and microhardness. The effect of La and Co atoms and annealing temperature on enhancement of glass forming ability, thermal stability and hardness of Al–Cu–Y based alloys were investigated. The results show the amorphous Al84Cu6Co2Y6La2 alloy with higher RE (Y, La) contents and more elements is thermally stable up to 618±2 K while primary crystallization occurs. It also indicates the highest hardness of 378.1 ± 15.3 HV which enhances even more to 394.2 ± 16.8 HV after primary crystallization due to nano-sized α-Al crystals formation. The hardness of the alloy decreases to 340.3 ± 16.4 HV after the second crystallization reaction, possibly because of the presence of some weak intermetallic compound, growth of the α-Al and crystallization of the amorphous matrix.

Structure and electrical properties of BaCe1−xLaxO3−δ mixed conductors

In this study, BaCe1−xLaxO3−δ (x = 0.05, 0.10, 0.20, and 0.30) oxides synthesized using citrate–nitrate combustion method were calcined at 1100 °C for 5 h and subsequently sintered at 1550 °C for 5 h. Crystal structure, conductivity, and chemical properties were investigated via X-ray diffraction (XRD), alternating current (AC) impedance spectroscopy, and X-ray photoelectron spectroscopy (XPS). XRD analysis shows that all samples have orthorhombic perovskite-type structure, and lattice volume increases with increasing La content. XPS results show that Ba and La valence states are bivalent, and trivalent, respectively. Mixed Ce4+ and Ce3+ valence states can be identified in the samples. Furthermore, there are two types of O binding states in perovskite structure: (i) O–H groups/oxygen vacancies and (ii) lattice oxygen. AC impedance spectra reveal that all samples are proton–oxide ion–electron hole conductors at 400–800 °C in wet O2 atmosphere and proton–electron conductors at 400–800 °C in wet Ar atmosphere. Among these samples, BaCe0.90La0.10O3−δ and BaCe0.95La0.05O3−δ display the highest conductivities at temperatures below and above 500 °C, respectively. Furthermore, BaCe0.95La0.05O3−δ exhibits the highest total conductivity of 1.06 × 10−2 S cm−1 at 800 °C under PO2 ≈ 1 atm and PH2O = 0.006 atm.

Role of spt23 in Saccharomyces cerevisiae thermal tolerance

spt23 plays multiple roles in the thermal tolerance of budding yeast. spt23 regulates unsaturated lipid acid (ULA) content in the cell, which can then significantly affect cellular thermal tolerance. Being a Ty suppressor, spt23 can also interact with transposons (Tys) that are contributors to yeast’s adaptive evolution. Nevertheless, few studies have investigated whether and how much spt23 can exert its regulatory functions through transposons. In this study, expression quantitative trait loci (eQTL) analysis was conducted with thermal-tolerant Saccharomyces cerevisiae strains, and spt23 was identified as one of the most important genes in mutants. spt23-overexpression (OE), deletion (Del), and integrative-expressed (IE) strains were constructed. Their heat tolerance, ethanol production, the expression level of key genes, and lipid acid contents in the cell membranes were measured. Furthermore, LTR (long terminal repeat)-amplicon sequencing was used to profile yeast transposon activities in the treatments. The results showed the Del type had a higher survival rate, biomass, and ethanol production, revealing negative correlations between spt23 expression levels and thermal tolerance. Total unsaturated lipid acid (TULA) contents in cell membranes were lower in the Del type, indicating its negative association with spt23 expression levels. The Del type resulted in the lower richness and higher evenness in LTR distributions, as well as higher transposon activities. The intersection of 3 gene sets and regression analysis revealed the relative weight of spt23’s direct and TY-induced influence is about 4:3. These results suggested a heat tolerance model in which spt23 increases cell thermal tolerance through transcriptional regulation in addition to spt23-transposon triggered unknown responses.Key points• spt23 is a key gene for heat tolerance, important for LA contents but not vital.• Deletion of spt23 decreases in yeast’s LTR richness but not in evenness.• The relative weight of spt23’s direct and TY-induced influence is about 4:3.

Epitaxial growth and phase evolution of ferroelectric La-doped HfO2 films

Hafnium-oxide-based materials are considered a promising candidate for next-generation nonvolatile memory devices owing to their good CMOS compatibility and robust ferroelectricity at the nanoscale. In this work, we synthesize highly (111)-oriented La-doped HfO2 (HLO) ferroelectric thin films via pulsed laser deposition. Furthermore, the effect of La dopant concentration, thickness, and growth temperature on the ferroelectricity of HLO films is investigated in detail. A maximum remnant polarization of ∼9 μC/cm2 is achieved for only the 5-nm-thick 3 mol. % HLO films without a wake-up process. The 180° inversion of the domain, the butterfly-shaped capacitance–voltage curve, and typical ferroelectric displacement current curve further demonstrate the robust ferroelectricity at the nanoscale. Moreover, the phase evolves from the monoclinic to the orthorhombic and subsequently to the cubic phase with increasing La concentration, which is due to the combined action of oxygen vacancy, epitaxial strain, and chemical pressure. Additionally, in the interface configuration of HLO/La0.7Sr0.3MnO3 (LSMO), the MnO20.7− layer is substituted by the HLO layer on the MnO2-terminated surface of LSMO, which can be attributed to the fact that the HLO layer with higher electronegativity replaces the MnO20.7− layer with the same electronegativity in the HLO film. Therefore, this study provides a reliable pathway for directly obtaining a lightly doped HLO ferroelectric thin film, which can help to broaden the understanding of the ferroelectric physical mechanisms with element doping.

Ce site dilution effects in the antiferromagnetic heavy fermion CeIn3

La-doped intermetallic single crystals of ${{\mathrm{Ce}}_{1}}_{\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{In}}_{3}$ were synthesized via an In self-flux method throughout the entire range $(x=0--1)$. The prototypical heavy-fermion compound ${\mathrm{CeIn}}_{3}$ shows an antiferromagnetic phase transition at 10.1 K and becomes superconducting near a critical pressure where ${T}_{N}$ is completely suppressed. As the La concentration increases, Ce moments are diluted, and the lattice constant increases linearly, satisfying Vegard's law. The electrical resistivity of the high-quality single crystals of ${{\mathrm{Ce}}_{1}}_{\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{In}}_{3}$ shows a gradual suppression of ${T}_{N}$ to 0 K at approximately ${x}_{c}=0.65$. The sign of the slope of the low-temperature resistivity vs temperature changes from positive to negative in the vicinity of the critical concentration ${x}_{c}$, indicating a change in the Kondo ground states from the Kondo lattice to the Kondo impurity state. In the Kondo lattice state $(x<{x}_{c})$, the coherence temperature $(=50\phantom{\rule{0.16em}{0ex}}\mathrm{K})$ assigned as the peak in the resistivity is almost independent of the La concentration. In the Kondo impurity state $(x>{x}_{c})$, on the other hand, a kinklike feature in the resistivity appears at $\ensuremath{\sim}50\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and persists up to $x=0.97$, indicating a change of the Kondo scattering owing to the crystalline electric field effects. These results suggest that the critical concentration is closely connected to the emergence of the Kondo coherence state.

Enhancement in room temperature ammonia sensing performance of the La substituted SnO2 (La:SnO2) thin films developed using spray pyrolysis technique

In this report, pristine SnO2 and La doped SnO2 (La:SnO2) thin films were synthesized using the spray pyrolysis technique and their gas sensing performance operated at room temperature in the presence of ammonia (50 to 250 ppm) were analyzed. The La:SnO2 thin films were developed in four different La concentration like 0, 1, 3 & 5% in SnO2. All the prepared thin film samples were characterized using different analytical techniques for analyzing their properties. The XRD result shows the prepared La:SnO2(0, 1, 3 & 5%) thin films exhibits a tetragonal rutile structure of SnO2 without any secondary impurities according the JCPDS data (41–1445). Also, the crystallite size increases with the La doping concentration at 1% and decreases with further increase in La concentration (3 & 5%) could due to the deterioration of the grain growth of the Sn-O lattice. The scanning electron microscope (SEM) results shows the La:SnO2 thin films possess a tetragonal structures with different nano size particles and the energy dispersive x-ray analysis (EDX) confirms the presence of Sn, O & La elements. The optical results suggest that the transparency increases with the introduction of the La dopants slightly shifted towards the blue region. The bandgap of the samples increases with the increase in La concentration which is according to the Moss- Burstein effect. The photoluminescence (PL) studies confirms the 1% La:SnO2 thin films has higher defect sites due to the presence of oxygen vacancies. Finally, the gas sensing properties of the samples shows that the 1% La:SnO2 exhibits high response of 128% for 250 ppm of ammonia gas at room temperature. Also, 1% La:SnO2 possess stable current value for the fixed concentration of ammonia (250 ppm) during five cycles. This results suggests that the fabricated 1% La:SnO2 thin film sensor can be better suited for the commercial gas sensing application.

Electrical transport properties of La doped BiFeO3-NaNbO3 composite

ABSTRACT The composites, (1−x)(BiFe1-yLayO3)– xNaNbO3 with x = 0.25, 0.45 and y = 0.10, 0.20, are prepared by mixed oxide method. XRD analysis shows rhombohedral (hexagonal) structure at room temperature. The properties such as dielectric loss (tanδ) and dielectric constant (ϵr ) of all the samples are studied. A significant improvement in dielectric constants has been observed with the rise of Lanthanum (La) content. A dielectric anomaly above 350°C is observed for all the studied materials. Further, it is observed that ac conductivity (σ ac) spectrum obeys universal Jonscher’s power law. The variation of σ ac with inverse of temperature for all the samples is found to obey the Arrhenius equation. The formation of loop in polarisation verses electric field curve establishes the ferroelectric (FE) nature of all the studied samples. Current (I)-Electric Field (E) loops is studied to show the behaviour of domain switching.

Effect of La on microstructure, mechanical properties and fracture behavior of Al/Mg bimetallic interface manufactured by compound casting

• Effect of La on microstructure and mechanical properties of Al/Mg interface was studied. • RE precipitates were preferentially precipitated at the interface with La addition. • Eutectic structure and primary γ dendrites at the interface were refined obviously. • Interface was strengthened under refinement and precipitation strengthening. • Shear strength of the Al/Mg bimetal increased by 30.95% with La addition. To improve the Al/Mg bimetallic interface, La was added into the Al/Mg bimetallic interface manufactured by a compound casting process. The effect of La addition on the microstructure, mechanical properties and fracture behavior of the Al/Mg bimetallic interface and the formation mechanism of the interface were studied in detail. Al 11 La 3 , Al 8 Mn 4 La, Al 20 Ti 2 La, and other rare earth precipitates (RE precipitates) preferentially precipitated at the interface with La addition, while the number of the Al 11 La 3 and Al 8 Mn 4 La located in eutectic structure area ( E area) gradually increased and aggregated in the interface with the increase of the La content. Besides, the matrix structure in different areas of the Al/Mg interface changed in different degrees, and the eutectic structure and primary γ (Mg 17 Al 12 ) dendrites in the E area were refined, but the intermetallic compounds area (IMC area) had no obvious change. With the addition of the La, the interface was strengthened under the comprehensive effect of refinement strengthening and precipitation strengthening from the E area. When the La content increased to 1.0%, the shear strength of the Al/Mg bimetal reached the maximum of 51.54 MPa, which was 30.95% higher than the group without La addition. However, with the further increase of the La content, the large area aggregation of the Al 11 La 3 and Al 8 Mn 4 La occurred in the interface, leading to the separation of the matrix structure of the E area and the decrease of the shear strength of the Al/Mg interface.

Controlled growth of Bi-Functional La doped CeO2 nanorods for photocatalytic H2 production and supercapacitor applications

The rapid increase in energy consumption has severely rehabilitated human life urging to develop reliable and environmental friendly energy storage devices. Target oriented, systematic approach has been adopted to synthesis La doped CeO 2 nanostructures with percentage as La x Ce 1-x O 2 (X = 0,1,3,5,7) for potential super capacitors applications. Morphological doping impact on H 2 production, electrochemical and optical properties are thoroughly investigated. XRD studies revealed the crystalline phase purity and attained approximately 35 nm average crystallite size. The SEM images exposed that primary morphology nano-particles has been tuned into nanorods by increasing the La concentration in CeO 2 with size range 40∼60 nm. CV graphs depicted that the prepared electrodes obey the pseudo capacitive faradaic reactions behavior in nature. Maximum capacitance (925 F g -1 ) has been achieved by La 0·05 Ce 0·95 O 2 which is better than numerous reported materials. The La 0·05 Ce 0·95 O 2 also exhibited excellent GCD stability with 87.8% retention exhibiting it suitability for supercapacitor applications. Furthermore, the La 0·05 Ce 0·95 O 2 showed the significantly higher H 2 (9 μmol h −1 g −1 ) production rate as compared to undoped CeO 2 and La 0·01 Ce 0·99 O 2, La 0·03 Ce 0·97 O 2 samples. This higher production is attributed to the recombination rate and have strong substantial correlation with optical characteristics. • La doped CeO 2 nanorods successfully synthesized by hydrothermal method. • Specific capacitance 925 F g -1 has been achieved for La 0·05 Ce 0·95 O 2 nanorods. • More than 87% cyclic stability was achieved for La 0·05 Ce 0·95 O 2 nanorods. • The La 0·05 Ce 0·95 O 2 showed the significantly H 2 production rate (9 μmol h −1 g −1 ).

Methane production of rare earth element‐rich Dicranopteris dichotoma and effects of La(III) on anaerobic digestion performance of lignocellulose

AbstractBACKGROUNDPhytoremediation by hyperaccumulators (such as Dicranopteris dichotoma) is widely used for the remediation of rare earth tailings in China. Accordingly, a large amount of rare earth‐rich plant residues is produced. Anaerobic digestion could convert biomass into energy. In this study, the anaerobic digestion performance of D. dichotoma, which is rich in rare earth elements (REEs), was investigated. Cellulose, xylan, and glucose served as the model substrates to explore the effects of La(III) on hydrolysis and methane production using batch anaerobic digestion.RESULTSThe results indicated that the La(III) concentration of 500 mg/L inhibited methane production from cellulose with the reduciton of 20%. Inversely, no significant difference was found in the cumulative methane yield from glucose with different La(III) concentrations. The microbial community results showed that the lack of cellulose hydrolyzing bacteria, such as Clostridium III and Clostridium XlVa, may be the main reason for the inhibition of methane production. Furthermore, the methane yield of REE‐rich D. dichotoma was 181.5 ± 14.6 mL/g VS and the La(III) concentration of luquid digestate was only 2.20 mg/L.CONCLUSIONThe inhibition of La(III) on anaerobic digestion of lignocellulose was mainly in the hydrolysis process of cellulose, while the inhibition of xylan hydrolysis was relatively weak, and it had no significant effect on methanogenesis process of glucose. La(III) showed a small effect on the methane production of REE‐rich D. dichotoma due to a small amount of release into the liquid digestate. Anaerobic digestion may be a feasible way for treating lignocellulose plants contaminated with rare‐earth minerals. © 2022 Society of Chemical Industry (SCI).

Comparative Study of the Effects of La-Substituted Ca in (Bi, Pb):2212 and (Bi, Pb):2223 Superconductors

We report here a comparative study of the effects of La-substituted Ca on (Bi, Pb):2212 and (Bi, Pb):2223 superconductors with various La content (0.00 ≤ x ≤ 0.30). Regardless of the effects of La, it is evident that the superconducting volume fraction, excess of oxygen, critical concentration for quenching superconductivity, Vickers hardness, anisotropy, interlayer coupling, critical magnetic fields, and critical current were higher for the 2212 series than the 2223 series. In contrast, orthorhombic distortion, c-parameter, crystallite diameter, doping distance, distance between two Cu atoms, hole carrier/Cu ion ratio, melting temperature Tm, critical temperature Tc, onset of diamagnetic TcM, surface energy, elastic component, resistance pressure, and c-axis coherence length were higher for the 2223 series than the 2212 series. An inverse linear relationship between Tm and Tc was estimated for both series, and for room-temperature (RT) bismuth–strontium–calcium–copper–oxide (BSCCO) superconductors, the required Tm values should be 1048.03°C for the 2223 series and 784.48°C for the 2212 series. Surprisingly, the difference in temperature between zero resistivity and diamagnetic onset |TcM − TcR| for La = 0.30 samples is 30 K. In the critical field region (CFR), the exponents of order parameters (OPD) are two-dimensional (2D), but their values were higher for the 2212 series than the 2223 series. Further, they became three-dimensional (3D) as La increased to 0.30 due to the reduced effective length in highly substituted samples. Our results were discussed with the help of the differences in the physical parameters between the considered series. These findings revealed that the 2212 series is more suitable for applications that need higher hardness and critical fields and currents. In contrast, the 2223 series is more suitable for research for higher Tc and altering plastic deformation. To our knowledge, the present systematic investigation has not been reported elsewhere, which highlights the present work.

Effects of Lactic Acid Bacteria and Molasses Additives on Dynamic Fermentation Quality and Microbial Community of Native Grass Silage.

Ensiling native grass is an effective method to protect the nutritional quality of forage and alleviate feed shortages in the cold winter of the Inner Mongolian Plateau. To improve the usability of native grass resources as feed in China, the effects of lactic acid bacteria and molasses additions on the microbial population, fermentation quality, and nutritional quality of native grass during silage were investigated. Treatments were a control treatment with no additive (CK), lactic acid bacteria (L), molasses (M), and lactic acid bacteria in combination with molasses (L+M), all of which were stored at ambient temperature (17–28°C) for 7, 14, 30, and 60 days. The results showed that all additives improved nutritional value and fermentation quality with low pH and ammonia nitrogen (NH3–N) and high crude protein (CP) and water soluble carbohydrate (WSC) than control silage over the ensiling period. Compared with L or M silage, the L+M silage combination improved fermentability, as evidenced by higher LA content and a faster pH drop during the first 7 days of ensiling. With prolonged ensiling time, the combined addition of L and M could increase the count of desirable Lactobacillus, decrease microbial diversity, and inhibit the growth of undesirable microorganism, such as Clostridia, Escherichia, and Enterobacter abundance compared with silage treated with CK, L. or M. Application of L together with M could further improve the silage quality of native grass by altering bacterial community structure. In summary, the addition of lactic acid bacteria and molasses increased the relative abundance of Lactobacillus of native grass silage and improved fermentation quality.

Effect of La addition on Ag-rich phase formation and mechanical properties of Cu-2Ag alloys

A series of novel Cu-2Ag-xLa alloys with reinforced mechanical properties and enhanced electrical conductivities are developed. The effects of La addition on the microstructural features and mechanical properties of as-cast and solution treated Cu-2Ag alloys are systematically investigated. The yielding strength of as-cast Cu-2Ag alloys with 0.02La and 0.07La (wt.%) is considerably reinforced by relative amounts of 55.56% and 30.16%, respectively. The strengthening mechanism for such increased yielding strength is mainly related to the shifting of interfacial relation between matrix and Ag-rich phase from original semi-coherent type to non-coherent type with La doping. Consequently, the interface barrier strength is enhanced by the non-coherent interface, and contributes to the increased yielding strength. Meanwhile, the strengthening effect from La addition closely depends on the exact contents of La element. As La content increases from 0.02 to 0.07 (wt.%), the strengthening effect becomes weaker because of the increased space of Ag-rich phases leading to an 16.33% decrease in yield strength. Additionally, La has dual effects on the dissolution of Ag-rich phases and precipitation of new La-rich phase in the as-cast alloys during solution treatment. Simultaneously, the precipitation of the La-rich phase abnormally enhances the electrical conductivity of the solution La-containing alloys when the solution time exceeds 24 h.

The formation mechanism of Al-RE tubular phase in AZ80-Ce magnesium alloy by La doping

In this paper, the effect of La addition on the Al-RE phase in Mg-Al-Zn-Ce magnesium alloy was studied. Melting method was used to prepare AZ80-Ce magnesium alloys with different La content, and the morphological transformation mechanism of Al-RE phase was proposed by XRD, SEM, EPMA, TEM and extraction. The results show that the Al11RE3 phase can be formed by adding RE (Ce/La) into AZ80 magnesium alloy. With the increase of La, the morphology of Al11RE3 phase in the alloy changes from acicular to tubular. La replaces part of Ce in the Al11Ce3 cell and the Al11Ce3 phase is transformed into Al11RE3 phase based on Al11RE3 cell when La is added. In the Al11RE3 phase, the doping of La will cause lattice distortion in the crystal, which increases the surface energy on the growth surface of the Al11RE3 phase and accelerates its growth rate in (001) direction, resulting in the formation of tubular Al11RE3 phase. After forming the tubular structure, the growing process of Al11RE3 phase is divided into three stages owing to different control factors.

Dual Roles of Coconut Oil and Its Major Component Lauric Acid on Redox Nexus: Focus on Cytoprotection and Cancer Cell Death.

It has been reported that coconut oil supplementation can reduce neuroinflammation. However, coconut oils are available as virgin coconut oil (VCO), crude coconut oil (ECO), and refined coconut oil (RCO). The impact of coconut oil extraction process (and its major fatty acid component lauric acid) at cellular antioxidant level, redox homeostasis and inflammation in neural cells is hitherto unexplained. Herein, we have shown the antioxidant levels and cellular effect of coconut oil extracted by various processes in human neuroblastoma cells (SH-SY5Y) cultured in vitro. Results indicate VCO and ECO treated cells displayed better mitochondrial health when compared to RCO. Similar trend was observed for the release of reactive oxygen species (ROS), key oxidative stress response genes (GCLC, HO-1, and Nqo1) and inflammatory genes (IL6, TNFα, and iNOS) in SH-SY5Y cells. Our results signified that both VCO and ECO offer better neural health primarily by maintaining the cellular redox balance. Further, RCO prepared by solvent extraction and chemical refining process lacks appreciable beneficial effect. Then, we extended our study to find out the reasons behind maintaining the cellular redox balance in neuroblastoma cells by VCO and ECO. Our GC-MS results showed that lauric acid (C14:0) (LA) content was the major difference in the fatty acid composition extracted by various processes. Therefore, we evaluated the efficacy of LA in SH-SY5Y cells. The LA showed dose-dependent effect. At IC50 concentration (11.8 μM), LA down regulated the oxidative stress response genes and inflammatory genes. The results clearly indicate that the LA inhibited the neuroinflammation and provided an efficient cellular antioxidant activity, which protects the cells. The efficiency was also evaluated in normal cell line such as fibroblasts (L929) to cross-validate that the results were not false positive. Different concentration of LA on L929 cells showed high compatibility. From our observation, we conclude that VCO and ECO offers better cellular protection owing to their powerful antioxidant system. Therefore, we advocate the inclusion of either VCO and/or ECO in the diet for a healthy lifestyle.

Comparison of the Effect of Synthetic (Tannic Acid) or Natural (Oak Bark Extract) Hydrolysable Tannins Addition on Fatty Acid Profile in the Rumen of Sheep.

Simple SummaryTannins are known as water-soluble polyphenols with the ability to form complexes with macromolecules of dietary and endogenous origin. Thus, they are becoming increasingly popular among scientists as an invaluable “tool” for targeted modification of digestive processes in the rumen. The aim of the study was to compare the effect of tannins of various origin—oak bark extract (natural) vs. tannic acid (synthetic) on the fatty acid composition in the ruminal fluid of sheep. It was shown that both sampling time and animal diet had a significant effect on tested parameters, but this effect was varied. The addition of tannic acid to sheep diet had a greater influence on the fatty acid profile in the rumen than oak bark extract. Differences in the effects of tested additives may arise from the presence of various types of tannins in oak bark extract. Increased concentrations of C18:2 c9c12 and C18:3 c9c12c15 in sheep fed diet with tannic acid addition may suggest inhibition of the initial stage of fatty acid biohydrogenation. These promising results may increase knowledge about the action of such compounds on lipid metabolism in the rumen, and provide the basis for further research on health-promoting properties of ruminant products.The aim of the study was to compare two sources of tannins on fatty acids (FA) composition in rumen. Treatments were (g tannins/kg diet as-feed-basis) as follows: (1) no supplemental tannin addition (CON), (2) addition of 13 g of oak bark extract (OAK), and (3) 4 g of tannic acid (TAN). The basal diet contained 55:45 forage to concentrate ratio. Net consumption of tannins (g/d) was 4 g for both tannins sources. The study was performed on three Polish Mountain ewes fitted with rumen cannulas, and was divided into three experimental periods (I, II, and III). Both sampling time and animal diet had a significant effect on FA profile in the rumen fluid. In general, FA concentrations were higher before feeding in comparison to samples collected 2 and 4 h after feeding. In terms of dietary effect, it was shown that TAN addition had a greater influence on FA profile in the ruminal fluid than the OAK diet. Briefly, in the TAN group significantly increased concentrations of C18:2 c9c12 (linoleic acid, LA) 8 h after feeding (vs. control, CON and OAK), C18:3 c9c12c15 (α-linolenic acid, LNA) 4 h after feeding (vs. OAK), C20:3 n-6 before feeding (vs. CON), C20:4 before feeding (vs. CON and OAK) and 8 h after feeding (vs. OAK) were recorded. In contrast, OAK addition significantly reduced C20:3 n-6 concentration 2 h after feeding (vs. CON). In conclusion, increased concentrations of both LA and LNA in the rumen indicated that supplemental tannic acid may inhibit the initial stage of FA biohydrogenation in the rumen.

Impact of La on Structural, Morphological and Magnetic Properties of NiCoFe2O4 Nano Ferrites

Abstract: Ni0.2Co0.8Fe2-xLaxO4 (x = 0.02, 0.06, 0.10) nano ferrites have been synthesized by Sol-gel auto combustion method using urea as a fuel. The sample calcinations have been performed at 800 oC for 4 hours. The synthesized samples were subjected to study X-ray diffraction spectroscopy (XRD) for structural investigations. All the samples were found to constitute Face Centered Cubic (FCC) spinel structure belonging to the Fd3m space group. The XRD results show the single cubical phase formation in the heated samples. Energy-dispersive X-ray spectra confirmed the presence of Ni, Co, La Fe and O elements with no existence of any impurity. The average crystallite size was decreased by varying the concentration of La from 10 to 8 nm. The Field Emission Gun Scanning Electron microscopy (FEG-SEM) and Field Emission Gun transmission electron microscopy (FEG-TEM) have given the morphological study of the samples. It is also found that the value of the lattice constant decreases with increases in La concentration. The magnetic properties of the samples were investigated by using a vibrating sample magnetometer (VSM). The results obtained from VSM show that the value of both magnetization (Ms) and coercivity (Hc) decreases with an increase in diamagnetic La concentration. Keywords: Spinel ferrites, Sol-gel, SEM, TEM, VSM.

Enhanced hard-magnetic properties and thermal stability of nanocrystalline Ce-rich Ce-Fe-B alloys by combining La substitution and Si addition

To balance the utilization of rare-earth resource, Ce and La have been proposed to be employed in RE2Fe14B-type magnetic materials to produce fully high abundance rare-earth magnets. In this work, the effects of La on the phase constitution, microstructure and magnetic properties of melt spun (Ce1-xLax)17Fe78B6 alloys and (Ce1-yLay)17Fe75Si3B6 alloys have been systematically investigated. La effectively inhibits the formation of CeFe2 phase and increases the volume fraction of 2:14:1 phase. The TEM results indicate that La prefers to enter into intergranular phase and form bulk aggregations. La-substitution improves the remanence Jr, the maximum energy product (BH)max, curie temperature Tc and thermal stability, but reduces the coercivity Hc. Si modified (Ce1-yLay)17Fe75Si3B6 alloys exhibit better demagnetization curve squareness and superior magnetic properties than (Ce1-xLax)17Fe78B6 alloys due to the refined microstructure. In addition, Si-doped alloys show better thermal stability due to the enhanced curie temperature Tc. The results indicate that higher La content can be employed in Si doped Ce-Fe-B-based alloys for improved properties. The best combination of magnetic properties with (BH)max = 6.5 MGOe, Hc = 336 kA/m, Jr = 0.60 T and coercivity coefficient |β|=0.324 %/℃ is obtained in (Ce0.6La0.4)17Fe75Si3B6 alloy. The current work suggests that Ce-La-Fe-B alloys are potential to fabricate the so-called ‘Gap Magnets’, however, the composition modification is also required in order to improve their performance.

Impact of La engineered stable phase mixed precursors on physico-chemical features of Cu- based catalysts for conversion of CO2 rich syngas to methanol

The conversion of carbon oxides (CO + CO2) to methanol is promising enough in concomitant decrease in greenhouse effect along with the mitigation of energy crisis. However, the process still confronts low levels of CO2 conversion and development of highly efficient catalyst is a bid challenge. In the present work, a syngas feed rich in CO2 was employed to produce methanol over a streak of La promoted Cu/ZnO/MgO catalysts where a harmonized synergy between the La and active Cu sites as a function of La content is reported. XRD analysis of Cu/ZnO/MgO/La2O3 precursors indicated the relative concentration of aurichalcite or malachite galleries. The optimized catalyst (2.5 mol% La) demonstrated the amplified population of malachite phase whereas suppression in aurichalcite phase. Presence of mixed phase precursor reflected well in Cu dispersion, small sized stable Cu particles and improved methanol synthesis activity with marginal deterioration in catalytic efficiency over 60 h on stream. A thorough investigation revealed that introducing La not only generated the required moderate basic sites but also enriched the catalytic surface with active Cu. XPS results indicated that La regulates interaction between Cu2+ and La3+ species, ultimately modifying the surface Cu/Zn ratio. CZ-M17.5La2.5 catalyst showed the highest carbon conversion with a methanol selectivity of 72.2% at 260 °C. This proves that La plays a crucial role towards methanol synthesis when blend of CO/CO2 is used as a feed.