Elongation Products Research Articles

Design of tri-phase lamellar architectures for enhanced ductility in ultra-strong steel

Achieving exceptional ductility in ultra-high strength steels has long been a formidable challenge, particularly when the yield strength reaches 2.0 GPa. In this study, we have designed an innovative tri-phase lamellar microstructure in medium Mn steel that successfully achieves both an ultrahigh yield strength of approximately 2.0 GPa and an impressive uniform elongation ranging from 22.5 % to 24.5 %. The ultra-high yield strength of this steel is primarily due to the ultrafine lamellar grain with high-density dislocations and HDI strengthening resulting from meticulously designed tri-phase lamellae. The remarkable ductility is attributed to the synergistic action of multiple plasticity mechanisms. The inherently excellent plasticity of the lamellar ferrite, in coordination with the lamellar martensite, generates significant HDI hardening, thereby suppressing the onset of necking in the early stages of deformation. During the mid-stage of deformation, high strain activates the transformation-induced plasticity effect in the highly stable austenite, which remains stable due to substantial HDI hardening and effectively mitigates strain localization. In the later stages of deformation, delamination cracking relieves stress accumulation at the interfaces, delaying material failure. These mechanisms elevate yield strength and uniform elongation product to 47.3 GPa·%, showcasing the tri-phase lamellar structure’s potential for ultrahigh-strength, high-ductility steels.

The influence of annealing temperature on the microstructure and mechanical properties of Fe-0.52 C-11Mn-5.14Al-1Cr lightweight steel

Steel used in the automotive industry must strike a delicate balance between strength and ductility to maintain the structural integrity of vehicles and achieve intricate designs. Traditional methods of reducing weight by using high-strength low-carbon steels have limitations. As a result, a new dual-phase lightweight steel with an austenite-ferrite structure and the composition Fe-0.52 C-11Mn-5.14Al-1Cr was developed. The relationship between the microstructure and mechanical properties of this lightweight steel, which underwent various annealing processes (700°C-1000°C) after cold rolling, was examined using specialized equipment like a universal testing machine, electron microscopy, and X-ray diffractometer. The findings reveal that the cold-rolled test steel (CR) exhibits high tensile strength (1500 MPa) but low elongation at break (3.9 %). The performance of the experimental steel post-annealing treatment has shown significant improvement, with the average grain size increasing with higher annealing temperatures. The γ phase generally shows an increasing trend, with finer grains post-annealing, and the distribution of the α phase displays a consistent pattern along γ boundaries. Additionally, a substantial number of annealing twins appear in the matrix. These twin boundaries absorb some dislocations, and slip leads to the movement of twin boundaries, effectively reducing stress concentration from deformation and enhancing the ability of twin boundaries to accommodate plastic strain, creating twin dislocation interaction. The interplay among dislocations, stacking faults, and twins regulates the balance between strength and plasticity. Following treatment at 850°C × 1 min + 500°C × 3 min, the steel displays excellent mechanical properties, including ultimate tensile strength (836 MPa), elongation (53 %), and strength-ductility product (43,723 MPa·%). This study identifies a specific heat treatment parameter that achieves a harmonious equilibrium between outstanding strength and plasticity (strength-ductility product) within the designed composition.

Life cycle assessment of n-caproic acid production via chain elongation from food waste: Comparison of shunting and staged technology

n-Caproic acid is a widely used biochemical that can be produced from organic waste through chain elongation technology. This study aims to evaluate the environmental impacts of n-caproic acid production through chain elongation by two processes (i.e., shunting and staged technology). The Open-life cycle assessment (LCA) model was used to calculate the environmental impacts of both technologies based on experimental data. Results showed that the shunting technology had higher environmental impacts than the staged technology. Water and electricity made bigger contribution to the environmental impacts of both technologies. Reusing chain elongation effluent substituting for water and using electricity produced by wind power could reduce the environmental impacts of water and electricity effectively. Using ethanol from food waste had higher global warming potential than fossil ethanol, which suggested that a cradle-to-grave LCA is needed to be carried out for specific raw materials and chain elongation products in the future.

Excellent combination of strength and elongation of TZM alloys achieved by c-ZrO2 and single cross rolling

In this study, new TZM-xZrO2 (x = 0, 0.5, 1, 1.5) (wt%) alloys were designed by powder metallurgy solid-solid mixing method combined with single cross rolling. The results show that c-ZrO2 in TZM alloys was mainly spherical, and the average size of c-ZrO2 particle increases gradually from 1.28 μm to 1.71 μm with the increase of its content. c-ZrO2 can effectively refine the molybdenum grain and adsorb the free brittle element O in grain boundaries in the form of TiO2 layer. The interface was composed of three phase: c-ZrO2, Y2O3 and TiO2, with the presence of [0−11] c-ZrO2 ǁ [−11−2] Y2O3 ǁ [−10−3] TiO2 crystal relationship. The rolled plates mainly exist 〈100〉//ND and 〈111〉//ND two kinds of grain orientation, the addition of c-ZrO2 particles promote <100>//ND orientation ratio, thus weakening the texture strength (maximum pole density value from 8.34 to 5.39), conducive to the improvement of plasticity. When the c-ZrO2 content was 0.5 wt%, the best performance was achieved, with good strength and elongation (ultimate tensile strength: 958 MPa; Elongation: 17.3%), showing excellent strength and elongation product (16.6 GPa·%), 31% higher than TZM alloy, better than most reported molybdenum alloys. With the further increase of c-ZrO2 content, the particles gradually coarsened, the hindering effect on dislocations was weakened, and it was easy to become the nucleation site of main cracks, resulting in the decrease of strength and plasticity. Fine grain strengthening and dislocation strengthening were important factors to improve the strength. The excellent ductility was mainly due to the deflection mechanism of microcracks and the blocking effect of grain boundary enrichment on crack propagation.

Phosphoramidate Azole Oligonucleotides for Single Nucleotide Polymorphism Detection by PCR.

Detection of the Kirsten rat sarcoma gene (KRAS) mutational status is an important factor for the treatment of various malignancies. The most common KRAS-activating mutations are caused by single-nucleotide mutations, which are usually determined by using PCR, using allele-specific DNA primers. Oligonucleotide primers with uncharged or partially charged internucleotide phosphate modification have proved their ability to increase the sensitivity and specificity of various single nucleotide mutation detection. To enhance the specificity of single nucleotide mutation detection, the novel oligonucleotides with four types of uncharged and partially charged internucleotide phosphates modification, phosphoramide benzoazole (PABA) oligonucleotides (PABAO), was used to prove the concept on the KRAS mutation model. The molecular effects of different types of site-specific PABA modification in a primer or a template on a synthesis of full-length elongation product and PCR efficiency were evaluated. The allele-specific PCR (AS-PCR) on plasmid templates showed a significant increase in analysis specificity without changes in Cq values compared with unmodified primer. PABA modification is a universal mismatch-like disturbance, which can be used for single nucleotide polymorphism discrimination for various applications. The molecular insights of the PABA site-specific modification in a primer and a template affect PCR, structural features of four types of PABAO in connection with AS-PCR results, and improvements of AS-PCR specificity support the further design of novel PCR platforms for various biological targets testing.

Simultaneous medium chain carboxylic acids and 1,3-propanediol production in a bioaugmented lactate-based chain elongation induced with glycerol

The objective was to investigate the impact of the bioaugmentation on chain elongation process using glycerol, lactate and lactose as substrates in an open culture fermentation. In the batch trials the highest selectivity for chain elongation product, i.e. caproate, was observed in trials inoculated with co-culture of Megasphaera elsdenii and Eubacterium limosum grown on glycerol (28.6%), and in non-bioaugmented open culture run on lactose + lactate (14.8%). The results showed that E. limosum, out of two bioaugmented strains, was able to survive in the open culture. A continuous open culture fermentation of glycerol led to caproate and 1,3-propanediol (1,3-PDO) formation, while lactate addition led to 1,3-PDO and short chain carboxylates production. Moving the process into batch mode triggered even-carbon chain elongation. Presence of E. limosum promoted odd-carbon chain elongation and valerate production. Imaging flow cytometry combined with machine learning enabled the discrimination of Eubacterium cells from other microbial strains during the process.

Effects of preheating-ultrasonic synergistic on the microstructure and strength-ductility of 24CrNiMoY alloy steel by laser directed energy deposition

Laser additive manufacturing alloy steel with good strength-ductility has important application prospects in the manufacturing of critical equipment parts. However, the poor matching of strength-ductility caused by high tensile strength and low elongation is a bottleneck problem that restricts the laser directed energy deposition (LDED) technology application. In this paper, based on the previous research on single physical field treatment, a new method to prepare alloy steel samples with better strength-ductility match by using compound physical field treatment (preheating/ultrasonic dual-field) to assist LDED alloy steel is proposed, thus solving the technical bottleneck problem of poor strength-ductility. The results show that the dual-field synergy has a more significant modulating effect on the densities, phase composition ratio, grain size, and strength-ductility matching properties of 24CrNiMoY alloy steel than the single field assistance by LDED. The density of the sample prepared with dual-field assistance was as high as 99.9%, and the phase compositions were ultra-fine crystalline lower bainite, granular bainite and residual austenite, with the average grain size refined from 0.46 μm to 0.26 μm. The ultimate tensile strength, elongation and strength-plastic product at break of the sample prepared by 360 W and 100 °C were (1058 ± 4.2) MPa, (13.8 ± 0.9)% and (14.6 ± 3.7) GPa%, respectively. A remarkable improvement of 12.3% in the strength-plastic product at break was achieved compared with the single ultrasonicated sample. The dual-field synergistic mechanism is the sufficient heterogeneous nucleation and cooling rate, which promoted the transformation of bainite morphology from lath to granular. The combined effect of the two aspects resulted in a satisfactory strength-ductility matching of the prepared alloy steel. This study will provide a promising theoretical and practical reference for the preparation of better strength-ductility matching alloy steel by dual-field-assisted LDED.

Evolution of Microstructures and Mechanical Properties of Nb-V Alloyed Ultra-High Strength Hot Stamping Steel in Austenitizing Process.

Clarifying the influence of Nb and V microalloying on the ultra-high strength hot stamping steel (UHSHSS) and exploring appropriate process parameters are the basis for effectively regulating properties of the final product. In this study, the effects of different austenitizing temperatures and holding times on the phase transitions, grain sizes and mechanical properties of 22MnB5NbV with Nb and V alloyed are studied by using JMatPro thermodynamic calculations and experiments. By comparing with 22MnB5 without Nb and V alloyed, the effects of Nb and V elements on quenching microstructures, grain sizes and mechanical properties of UHSHSS are analyzed. The suitable austenitizing process parameters of 22MnB5NbV have been obtained. The results show that the grain size of Nb-V-alloyed UHSHSS grows with the increase in the austenitizing temperature and holding time. The 22MnB5NbV steel can be completely austenitized while the austenitizing temperatures ≥870 °C and holding time ≥3 min. Combined with the actual production process, the best austenitizing temperature and holding time are 930 °C and 3 min. Under these conditions, the average grain size is 7.7 μm, the tensile strength, elongation and strength-ductility product are 1570.8 MPa, 6.6% and 10.4 GPa·%, respectively. With the addition of Nb and V elements, the nanoscale precipitates lead to the refinement of the quenched structure and grain size, and the comprehensive properties of UHSHSS have been effectively promoted, in which the elongation and strong-plastic products are increased by ~0.6% and ~1.2 GPa·%, respectively.

Effect of Microstructure Morphology of Q&amp;P Steel on Carbon and Manganese Partitioning and Stability of Retained Austenite

In this study, we used 0.2C-1.7Si-1.9Mn wt% cold-rolled sheet as the experimental material to prepare the Q&amp;P sample with blocky microstructures and the QQ&amp;P sample with lath-shaped microstructures through the Q&amp;P and QQ&amp;P processes, respectively. The partitioning behavior of carbon and manganese in the two samples after intercritical annealing and partitioning were studied. During the intercritical annealing, the partitioning of carbon and manganese in the Q&amp;P and the QQ&amp;P samples occurred, resulting in the contents of carbon and manganese being significantly higher than those in the ferrite. Meanwhile, due to the migration of the ferrite–austenite interface during the formation of the austenite, the distributions of carbon and manganese in the lath-shaped and blocky austenite were both homogenous. The morphology of the microstructures had little influence on the distribution of carbon and manganese in metastable austenite during intercritical annealing. In the partitioning, the migration of the ferrite–austenite interface and diffusion of manganese can be ignored. Carbon first diffuses from the ferrite grains to the ferrite–austenite interface and then diffuses in the austenite grains. The morphology of the microstructures has a great effect on the homogenization of carbon in austenite grains. Compared with coarse blocky austenite, lath-shaped austenite can shorten the diffusion path of carbon in austenite grains and increase the homogeneity of carbon in austenite grains, thereby improving the thermal stability of lath-shaped austenite. Compared with the Q&amp;P sample, the QQ&amp;P sample has higher content of retained austenite (14.74% vs. 13.96%), better elongation (25.9% vs. 19.2%), and higher product of strength and elongation (27.5 GPa% vs. 24.4 GPa%).

Role of Al element in tailoring the austenite mechanical stability and tensile properties of medium Mn steels

Al is generally employed as a key alloying element to tailor the austenite mechanical stability and mechanical properties in medium Mn TRIP steels. However, the effect of Al on the austenite stability has been limitedly studied, leaving contradictory results without a self-consistent explanation. This study addressed this issue through a systematic study of medium Mn TRIP steels with compositions of 0.2C–8Mn-0/1.5/3Al (wt.%), while providing new insights into the factors influencing austenite stability and mechanical properties. It was found that the variation of the Mn distribution in austenite from non-equilibrium to near-equilibrium state and the weakened strain incompatibility between phases due to sufficient recovery of tempered martensite can be achieved with the addition of Al, which contributed to slowed strain-induced martensite transformation (SIMT) and improved austenite stability in the experimental steels annealed at low temperatures in the two-phases region, resulting in a decrease in ultimate tensile strength (UTS) and an increase in total elongation (TE). Furthermore, fully recovered tempered martensite with the hardness much lower than that of austenite was obtained in the 3Al steel annealed at a high temperature in the two-phase region, which led to a significant reduction in yield strength and thus low UTS. Meanwhile, heterogeneous strain distribution was induced by the remarkable gap in hardness between the two phases, which can be responsible for the relatively high austenite mechanical stability. The varying strain states and variation of Mn distribution in austenite can be achieved for the medium Mn TRIP steels with different Al contents, contributing to a wide range of UTS&TE combination with high strength and elongation product (≥40 GPa·%). And the elucidation of the effect of different strain states also opens a new window to adjust the austenite stability and mechanical properties of medium Mn TRIP steels.

Comparative study on microstructures and mechanical properties of Q&P steels prepared with hot-rolled and cold-rolled C–Si–Mn sheets

In this study, we investigate the microstructures and mechanical properties of quenching and partitioning (Q&P) steels prepared with hot-rolled (HR) and cold-rolled (CR) sheets at different annealing temperatures (partial austenitisation). The ferrite and retained austenite are present in laths and blocks in HR-Q&P samples but are mainly blocky in CR-Q&P samples. Compared with CR-Q&P, the HR-Q&P samples have higher content of retained austenite, better elongation and higher product of strength and elongation (PSE). The lath-shaped retained austenite in HR-Q&P samples with a higher ratio of surface to volume is conducive to homogenization of carbon in austenite grains, thus improving the thermal stability and content of retained austenite. The lath-shaped retained austenite transforms into martensite obviously until the strain exceeds 5% and exhibits higher mechanical stability than coarse blocky retained austenite. When annealed at 810 °C, HR-Q&P and CR-Q&P samples present best PSEs. Indeed, the PSE of HR-810°C-Q&P sample is 62.8% higher than that of CR%-810°C-Q&P. The better elongation and higher PSE possessed by HR-810°C-Q&P sample are linked with the higher content of retained austenite and the presence of two kinds of retained austenite with different mechanical stability. The retained austenite with different mechanical stability in HR-810°C-Q&P sample, contributes to continuous transformation during tensile deformation, thereby improving the elongation. Meanwhile, the lath-shaped structures can delay the formation of voids and microcracks, thereby improving the elongation.

Sensitive naked-eye detection of telomerase activity based on exponential amplification reaction and lateral flow assay.

Telomerase is a promising diagnostic and prognostic biomarker for cancers. Sensitive, simple, and reliable telomerase activity detection is vital for cancer diagnosis. Herein, we developed an ultrasensitive visualized assay for telomerase activity that combined the exponential amplification reaction (EXPAR) and lateral flow assay for easy and quick signal readout, which we termed as a lateral flow readout-EXPAR (LFR-EXPAR) assay. In the LFR-EXPAR assay, telomerase elongation products initiate the exponential amplification reaction, the generated trigger hybridizes with the reporter to form the recognition site of the nicking enzyme, and the nicking enzyme cuts the reporter strand. The degradation of the reporter can be detected with a universal lateral flow dipstick and read out with the naked eye. After conducting a series of proof-of-concept investigations, the LFR-EXPAR assay was found to achieve a sensitivity comparable to that of a TRAP (telomere repeat amplification protocol) assay. The LFR-EXPAR assay can be used to realize ultrasensitive and point-of-care detection of telomerase without requiring specialized instruments, holding great promise for early cancer diagnosis.

Molecular and Signaling Mechanisms for Docosahexaenoic Acid-Derived Neurodevelopment and Neuroprotection.

The neurodevelopmental and neuroprotective actions of docosahexaenoic acid (DHA) are mediated by mechanisms involving membrane- and metabolite-related signal transduction. A key characteristic in the membrane-mediated action of DHA results from the stimulated synthesis of neuronal phosphatidylserine (PS). The resulting DHA-PS-rich membrane domains facilitate the translocation and activation of kinases such as Raf-1, protein kinase C (PKC), and Akt. The activation of these signaling pathways promotes neuronal development and survival. DHA is also metabolized in neural tissues to bioactive mediators. Neuroprotectin D1, a docosatriene synthesized by the lipoxygenase activity, has an anti-inflammatory property, and elovanoids formed from DHA elongation products exhibit antioxidant effects in the retina. Synaptamide, an endocannabinoid-like lipid mediator synthesized from DHA in the brain, promotes neurogenesis and synaptogenesis and exerts anti-inflammatory effects. It binds to the GAIN domain of the GPR110 (ADGRF1) receptor, triggers the cAMP/protein kinase A (PKA) signaling pathway, and activates the cAMP-response element binding protein (CREB). The DHA status in the brain influences not only the PS-dependent signal transduction but also the metabolite formation and expression of pre- and post-synaptic proteins that are downstream of the CREB and affect neurotransmission. The combined actions of these processes contribute to the neurodevelopmental and neuroprotective effects of DHA.

The effect of camelina oil on vascular function in essential hypertensive patients with metabolic syndrome: a randomized, placebo-controlled, double-blind study

The effects of a dietary supplementation with the vegetable ω-3 α-linolenic acid (ALA) on cardiovascular homeostasis are unclear. In this context, it would be interesting to assess the effects of camelina oil. This study aimed to assess the cardiovascular and metabolic effects of camelina oil in hypertensive patients with metabolic syndrome. In a double-blind, placebo-controlled randomized study, treated essential hypertensive patients with metabolic syndrome received, during 6 mo, either cyclodextrin-complexed camelina oil containing≈1.5g ALA/d (n=40) or an isocaloric placebo (n=41), consisting of the same quantity of cyclodextrins and wheat starch. Anthropometric data, plasma lipids, glycemia, insulinemia, creatininemia, TBARs, high-sensitivity C-reactive protein, and n-3, n-6, and n-9 fatty acids in erythrocyte membranes were measured. Peripheral and central blood pressures, arterial stiffness, carotid intima-media thickness, and brachial artery endothelium-dependent flow-mediated dilatation (FMD) and endothelium-independent dilatation were assessed. Compared with placebo, camelina oil increased ALA (mean±SD: 0±0.04 compared with 0.08±0.06%, P<0.001), its elongation product EPA (0±0.5 compared with 0.16±0.65%, P<0.05), and the n-9 gondoic acid (GA; 0±0.04 compared with 0.08±0.04%, P<0.001). No between-group difference was observed for cardiovascular parameters. However, changes in FMD were associated with the magnitude of changes in EPA (r=0.26, P=0.03). Compared with placebo, camelina oil increased fasting glycemia (-0.2±0.6 compared with 0.3±0.5mmol/L, P<0.001) and HOMA-IR index (-0.8±2.5 compared with 0.5±0.9, P<0.01), without affecting plasma lipids, or inflammatory and oxidative stress markers. Changes in HOMA-IR index were correlated with the magnitude of changes in GA (r=0.32, P<0.01). Nutritional intake remained similar between groups. ALA supplementation with camelina oil did not improve vascular function but adversely affected glucose metabolism in hypertensive patients with metabolic syndrome. Whether this adverse effect on insulin sensitivity is related to GA enrichment, remains to be elucidated.

Phosphoryl guanidine oligonucleotides as primers for RNA-dependent DNA synthesis using murine leukemia virus reverse transcriptase.

Modern approaches to the detection and analysis of low-copy-number RNAs are often based on the use of RNA-dependent DNA polymerases, for example, in reverse-transcription PCR. The accuracy and eff iciency of cDNA synthesis in the reverse-transcription reaction catalyzed by reverse transcriptase (RNA-dependent DNA polymerase) signif icantly affect the correctness of the results of PCR diagnostic assays and/or RNA sequencing. In this regard, many studies are focused on the optimization of the reverse-transcription reaction, including the search for more perfect primers necessary to obtain a full-length DNA copy of RNA under study. The best-known completely uncharged analogs of oligonucleotides – morpholine oligonucleotides and peptide nucleic acids – cannot be substrates for enzymes that process nucleic acids. The aim of this work was to conduct a pilot study of uncharged phosphoryl guanidine oligodeoxyribonucleotides (PGOs) as primers for mouse leukemia virus reverse transcriptase (MMLV H-). Specif ic features of elongation of partially and completely uncharged PGO primers were investigated. It was demonstrated that PGOs can be elongated eff iciently, e. g., in the presence of a fragment of human ribosomal RNA having complex spatial structure. It was shown that the proportion (%) of abortive elongation products of a PGO primer depends on buffer ionic strength, nucleotide sequence of the primer, and the presence and location of phosphoryl guanidine groups in the primer. The results indicate the suitability of PGOs, including completely electroneutral ones, as primers for reverse-transcription PCR, thereby opening up new prospects for the creation of experimental models for the analysis of highly structured RNA.

Dietary novel oils modulate neural function and preserve locomotor response in gilthead sea bream (Sparus aurata) juveniles by regulating synthesis and contents of fatty acids in brain

N-3 long-chain polyunsaturated fatty acids (LC-PUFA), particularly docosahexaenoic acid (22:6n-3, DHA), are the most important fatty acids with physiological significance in brain function of all vertebrates. Recently, novel lipid sources are available for the industry, including products obtained from microorganisms. Dietary fatty acid profiles may affect tissue composition and cell functioning. To determine the effect of novel lipid sources on behaviour and neural function in gilthead sea bream (Sparus aurata), juveniles were fed three isoproteic and isoenergetic diets containing either (FO), a microalgae oil combined with poultry oil (DD) or only poultry oil (PO). Behaviour response, brain fatty acid composition and relative expression of neurogenesis and neural activity related-genes in telencephalon were evaluated during 5 months of feeding with the experimental diets. Brain of sea bream fed diet PO showed the highest DHA content as well as increased desaturation and elongation products, contrary to the dietary pattern. This, together with an increased telencephalic fads2 expression denoted the effective activation of LC-PUFA synthesis and retention as a compensatory mechanism for a dietary deficiency. Furthermore, neurod6, bdnf and nos1 were proportionally upregulated in relation to the neural DHA content. Locomotor performance during cruising and escape responses was not affected by the experimental diets. However, there was a tendency for escape latency to be longest in fish fed PO and DD diets, and a relationship between escape latency and brain n-6 docosapentaenoic acid (DPA) contents was suggested. Indeed, the relation of n-6 DPA with behavioural deficits was shown previously in mammals and might deserve further attention and corroboration in fish as well in the future.

Eicosapentaenoic acid membrane incorporation stimulates ABCA1-mediated cholesterol efflux from human THP-1 macrophages

A high intake in polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA) (C20:5 n-3), is cardioprotective. Dietary PUFAs incorporate into membrane phospholipids, which may modify the function of membrane proteins. We investigated the consequences of the membrane incorporation of several PUFAs on the key antiatherogenic ABCA1-mediated cholesterol efflux pathway. Human THP-1 macrophages were incubated with EPA, arachidonic acid (AA) (C20:4 n-6) or docosahexaenoic acid (DHA) (C22:6 n-3) for a long time to mimic a chronic exposure. EPA 70 μM, but not AA 50 μM or DHA 15 μM, increased ABCA1-mediated cholesterol efflux to apolipoprotein (apo) AI by 28% without altering aqueous diffusion. No variation in ABCA1 expression or localization was observed after EPA treatment. EPA incorporation did not affect the phenotype of THP-1 macrophages. The membrane phospholipids composition of EPA cells displayed higher levels of both EPA and its elongation product docosapentaenoic acid, which was associated with drastic lower levels of AA. Treatment by EPA increased the ATPase activity of the transporter, likely through a PKA-dependent mechanism. Eicosanoids were not involved in the stimulated ABCA1-mediated cholesterol efflux from EPA-enriched macrophages. In addition, EPA supplementation increased the apo AI binding capacity from macrophages by 38%. Moreover, the increased apo AI binding in EPA-enriched macrophages can be competed. In conclusion, EPA membrane incorporation increased ABCA1 functionality in cholesterol-normal human THP-1 macrophages, likely through a combination of different mechanisms. This beneficial in vitro effect may partly contribute to the cardioprotective effect of a diet enriched with EPA highlighted by several recent clinical trials.

The occurrence and ecology of microbial chain elongation of carboxylates in soils

Chain elongation is a growth-dependent anaerobic metabolism that combines acetate and ethanol into butyrate, hexanoate, and octanoate. While the model microorganism for chain elongation, Clostridium kluyveri, was isolated from a saturated soil sample in the 1940s, chain elongation has remained unexplored in soil environments. During soil fermentative events, simple carboxylates and alcohols can transiently accumulate up to low mM concentrations, suggesting in situ possibility of microbial chain elongation. Here, we examined the occurrence and microbial ecology of chain elongation in four soil types in microcosms and enrichments amended with chain elongation substrates. All soils showed evidence of chain elongation activity with several days of incubation at high (100 mM) and environmentally relevant (2.5 mM) concentrations of acetate and ethanol. Three soils showed substantial activity in soil microcosms with high substrate concentrations, converting 58% or more of the added carbon as acetate and ethanol to butyrate, butanol, and hexanoate. Semi-batch enrichment yielded hexanoate and octanoate as the most elongated products and microbial communities predominated by C. kluyveri and other Firmicutes genera not known to undergo chain elongation. Collectively, these results strongly suggest a niche for chain elongation in anaerobic soils that should not be overlooked in soil microbial ecology studies.

Effects of Al addition on microstructure and mechanical properties of extruded Mg–3Bi alloy

Effects of Al addition to a Mg–Bi binary alloy on its microstructural characteristics and tensile properties after extrusion are investigated via extrusion of Mg–3Bi–xAl (x = 0, 1, and 2 wt%) billets and analysis of the extruded materials. The Al addition negligibly affects the second-phase particles of the extruded alloy; however, an increase in the Al content causes significant decreases in the average grain size and maximum texture intensity of the extruded material owing to an increase in the area fraction of dynamically recrystallized (DRXed) grains. The Al addition improves the strength of the extruded alloy; this improvement is attributed to the enhanced grain-boundary hardening and solid-solution hardening effects induced by grain refinement and Al solute atoms, respectively. As the Al content increases from 0 wt% to 1 wt% and 2 wt%, the tensile elongation increases substantially from 2.8% to 9.4% and 16.9%, respectively. The reduction in the number and size of unDRXed grains with increasing Al content suppresses the formation and coalescence of cracks in the unDRXed grains during tension, which results in a significant improvement in the tensile ductility of the extruded material. During tensile deformation, large undesirable twins that act as crack initiation sites are locally formed in the unDRXed grains of the Mg–3Bi alloy, whereas relatively smaller twins are uniformly formed in both the DRXed and the unDRXed grains of the Mg–3Bi–2Al alloy. Consequently, the extruded Mg–3Bi–2Al alloy has a substantially higher tensile yield strength–elongation product (2924 MPa%) than the extruded Al-free B3 alloy (381 MPa%).

Do Eicosapentaenoic Acid and Docosahexaenoic Acid Have the Potential to Compete against Each Other?

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are n-3 polyunsaturated fatty acids (PUFAs) consumed in low abundance in the Western diet. Increased consumption of n-3 PUFAs may have beneficial effects for a wide range of physiological outcomes including chronic inflammation. However, considerable mechanistic gaps in knowledge exist about EPA versus DHA, which are often studied as a mixture. We suggest the novel hypothesis that EPA and DHA may compete against each other through overlapping mechanisms. First, EPA and DHA may compete for residency in membrane phospholipids and thereby differentially displace n-6 PUFAs, which are highly prevalent in the Western diet. This would influence biosynthesis of downstream metabolites of inflammation initiation and resolution. Second, EPA and DHA exert different effects on plasma membrane biophysical structure, creating an additional layer of competition between the fatty acids in controlling signaling. Third, DHA regulates membrane EPA levels by lowering its rate of conversion to EPA’s elongation product n-3 docosapentaenoic acid. Collectively, we propose the critical need to investigate molecular competition between EPA and DHA in health and disease, which would ultimately impact dietary recommendations and precision nutrition trials.