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A gene coding for GH5 endoglucanase exploited from metagnomic DNA data of bacteria in Vietnamese goats’ rumen was modularity structure including a catalytic module, a fibronectin-3 like module and an X module. The recombinant enzyme was sucessfully expressed in E. coli and purified. To study the effect of some metal ions and chemicals on enzyme activity, in this study, we used some tools including Swiss-Prot, ProFunc, COFACTOR for prediction of enzyme structure and ligands interaction. The obtained results indicated that the most similar structure with enzyme had two conserved residues (Asp-190 và Asp-192) linked with Mn2+ within a radius of ~ 3.5 Å from the center of ion Mn2+ and enzyme molecule contained a disulphide bond. Experimental results for essessment of the effect of some metal ions (Ca2 +, Mn2 +, Mg2+, Ni2+, K+, Co2+, Cu2+, Zn2+, Fe3+) at the final concentration of 10 mM and of six common chemicals including SDS (1%), urea (1 µM), 2-mercaptoethanol (1 µM), EDTA (1 µM), tween 80 (1mM), triton X-100 (1 µM) showed that only Mn2+ increased enzyme activity slightly at concentration of 10 mM and two times at the concentration of 40 mM Mn2+. The Mn2+ has been identified as a specific binding agent may increase the stability and activity of endoglucanase GH5.

Objective: Fibronectin 3 (FN3) and immunoglobulin like modules (Ig) are usually collocated beside modular cellulase catalytic domains. However, very few researches have investigated the role of these modules. In a previous study, we have sequenced and analyzed bacterial metagenomic DNA in Vietnamese goats' rumen and found that cellulase-producing bacteria and cellulase families were dominant. In this study, the properties of modular cellulases and the role of a FN3 in unique endoglucanase belonging to glycosyl hydorlase (GH) family 5 were determined.Methods: Based on Pfam analysis, the cellulases sequences containing FN3, Ig modules were extracted from 297 complete open reading frames (ORFs). The alkaline, thermostability, tertiary structure of deduced enzymes were predicted by AcalPred, TBI software, Phyre2 and Swiss models. Then, whole and truncated forms of a selected gene were expressed in Escherichia coli and purified by His-tag affinity column for assessment of FN3 ability to enhance enzyme activity, solubility and conformation.Results: From 297 complete ORFs coding for cellulases, 148 sequences containing FN3, Ig were identified. Mostly FN3 appeared in 90.9% beta-glucosidases belonging to glycosyl hydrolase family 3 (GH3) and situated downstream of catalytic domains. The Ig was found upstream of 100% endoglucanase GH9. Rarely FN3 was seen to be situated downstream of X domain and upstream of catalytic domain endoglucanase GH5. Whole enzyme (called XFN3GH5 based on modular structure) and truncate forms FN3, XFN3, FN3GH5, GH5 were cloned in pET22b (+) and pET22SUMO to be expressed in single and fusion forms with a small ubiquitin-related modifier partner (S). The FN3, SFN3 increased GH5 solubility in FN3GH5, SFN3GH5. The SFN3 partly served for GH5 conformation in SFN3GH5, increased modules interaction and enzyme-soluble substrate affinity to enhance SXFN3GH5, SFN3GH5 activities in mixtures. Both SFN3 and SXFN3 did not anchor enzyme on filter paper but exfoliate and separate cellulose chains on filter paper for enzyme hydrolysis.Conclusion: Based on these findings, the presence of FN3 module in certain cellulases was confirmed and it assisted for enzyme conformation and activity in both soluble and insoluble substrate.

Three new bis-trinorcadalenes, bistrinorcadintermes A–C (1-3) along with seven known compounds, parvifloral D (4), parvifloral E (5), parvifloral C (6), hymexelsin (7), scopoletin (8), scopolin (9), and hibiscolactone A (10) were isolated from the aerial parts and radix of Decaschistia intermedia Craib. Their chemical structures were determined based on spectroscopic methods, including 1D, 2D NMR, MS, and experimental CD spectra. All compounds were evaluated for their α-glucosidase inhibitory effects. Compounds 1, 5, and 8 showed moderate α-glucosidase inhibitory activities with IC50 values of 45.6 ± 4.2, 43.7 ± 3.6, and 43.7 ± 3.6 μg/mL, respectively. Compounds 2-4 and 10 showed weak α-glucosidase inhibitory activities with IC50 values ranging from 87.5 ± 6.3 to 219.8 ± 4.9 μg/mL.

Two new cadinane sesquiterpenes, cadinoschanes A and B (1 and 2), one new norlignan, lignanoschane A (6) along with seven known compounds, hibiscone B (3), 7β-O-β-glucopyranosyl bombaxone (4), 2,7β,8β-trihydroxy trans-calamenene 7-O-β-D-glucopyranoside (5), clemastanin A (7), (−)-3,4,3′,4′-tetrahydroxy-9,7′β-epoxylignano-7β,9′-lactone (8), N-trans-feruloyl tyramine (9), and methyl (3R)-3-[(3R)-3-{(3R)-3-hydroxybutanoyloxy} butanoyloxy} butanoate (10) were isolated from Abelmoschus moschatus subsp. tuberosus (Span.) Borss. Waalk. Their structures were determined on the basis of extensive spectroscopic methods, including 1D, 2D NMR and MS data and comparing experimental CD with theoretical CD calculations. Compounds 3 and 9 showed significant α-glucosidase inhibitory activity with IC50 values of 121.7 ± 3.9 and 4.3 ± 0.5 μg/mL, respectively, compared to those of a positive control, acarbose with IC50 value of 183.5 ± 12.2 μg/mL.

This study suggested a new method to produce the in vitro cartilage tissues by cartilage differentiation in spheroids from adipose-derived stem cells on porous scaffolds. Adipose-derived stem cells (ADSCs) were used to produce spheroids by the hanging-drop method. The spheroids were then loaded into a porous scaffold and induced to differentiate into cartilage. To confirm the cartilage phenotype of the differentiated spheroids in the scaffold, the complex was evaluated for the expression of chondrogenic-related genes and proteins. The cartilagenous tissues formed from the spheroid-scaffold complexes were primarily checked for in vivo functioning by transplanting them into rat models of cartilage damage. The results showed that the spheroid-scaffold complexes displayed the cartilage phenotype after inducing chondrogenic differentiation. The complexes stained positive with safranin O, alcian blue and collagen 2, significantly expressed Sox9, Col2, and aggrecan genes compared with that before differentiation. In vivo, the differentiated spheroid-scaffold complexes formed mature cartilage that stained strongly positive with safranin O and fast red. These results suggest a promising strategy to produce cartilaginous microtissue for regenerative medicine.

Introduction: Helicobacter pylori and Candida albicans are classified as the most common pathogenic agents in humans. H. pylori is responsible for gastroduodenal diseases and greatly associated with gastric carcinogenesis, while C. albicans is the main cause of fungal urinary tract, genital yeast, and fungal skin infections. The increasing appearance of drug-resistant strains of H. pylori and C. albicans has made the treatment of the infections more serious. Hydrosols from plant steam distillation have been traditionally used in medicine, cosmetics, and culinary uses. They have been recently suggested as antimicrobial agents owing to their safety and ability to reduce the potential of resistance. The aim of the present study is to assess antibacterial and antifungal activities of hydrosols extracted from the fresh fruits of Litsea cubeba against H. pylori and C. albicans. Methods: The L. cubeba fruit hydrosol was obtained by steam distillation method. Evaluation of the growth-inhibiting and microbicidal effects of the hydrosol towards the H. pylori ATCC 43504 and C. albicans ATCC 10231 was determined through MIC (minimal inhibitory concentration), MBC (minimal bactericidal concentration), and MFC (minimal fungicidal concentration) measurements using broth dilution assays. Compositions of the dissolved essential oil (dEO) from the hydrosol were analyzed by GC-MS (gas chromatography-mass spectrometry). Results: The results indicated that the L. cubeba fruit hydrosol exhibited strong antimicrobial ability towards the bacterium H. pylori (MIC of 10%, MBC of 30%) and the yeast C. albicans (MIC of 10%, MFC of 40%). The cells of H. pylori and C. albicans were killed completely after 24 and 18 hours of treatment with 30% and 40% of the hydrosol, respectively. The major constituents of the dEO were geranial (32.92%), neral (27.12%), p-menthan-8-yl acetate (8.45%), 2-cyclopropyl-2-methylspiro[2.2]pentane-1-carboxylic acid (8.09%), linalool (4.24%), and methyl heptenone (4.15%). Conclusion: The results of the study suggest that L. cubeba fruit hydrosols could be used as potent natural antibacterial and antifungal preparations in the global effort to discover safe alternatives to toxic antimicrobial agents.

Nattokinase is an enzyme with a strong fibrinolytic activity that can be used for preventing thrombolytic diseases. The fibrinolytic activity of the Nattokinase in dietary supplements is determined by spectrophotometric method. In this study, the conditions of the assay were examined and finally optimized as pH: 8.5, reaction temperature: 40oC, and reaction time: 60 minutes. The proposed method was validated and successfully applied to determine the Nattokinase activity in 10 dietary supplements. The results showed that the proportion of measured activity compared to label product activity were within in the range 79.1 - 98.0%. The effect of herbal compounds and excipients on Nattokinase activity were also surveyed. From the evaluated results and application to commercial samples, this method will be a valuable contribution to quality control of dietary supplement products containing Nattokinase. &nbsp

Introduction: Cartilage damage is one of the injuries that is difficult for the human body to self-repair due to the avascular and completely mature tissue with only few stem or progenitor cells present. Recently, some studies showed that engineered cartilage tissues could be used to treat or improve this injury. This study aimed to produce the cartilage microtissues from the differentiation of scaffold-free spheroids composed of human adipose-derived stem cells. Methods: Human adipose-derived stem cells (ADSCs) were isolated and expanded following the previously published study. They were then cultured in the non-adherent condition to produce spheroids. The spheroids of the ADSCs were collected and induced into cartilage microtissues in the inducible medium for 21 days. The cartilage microtissue was characterized by some cartilage phenotype markers, including the accumulation of extracellular matrix proteins (aggrecan, glycosaminoglycan, and type II collagen), and the expression of certain genes specific to chondrocytes (Sox9, Col2, Col1, and Acan). Results: The results showed that the expression of chondrocyte-specific genes gradually increased during the 21 days of culture for differentiation. On day 21, the microtissues expressed aggrecan, glycosaminoglycan, and type II collagen proteins. Conclusion: This study demonstrated that cartilage microtissues could easily be produced from scaffold-free spheroids from ADSCs. Thus, cartilage microtissues can be produced in this manner for in vivo transplantation to promote cartilage regeneration, or to produce cartilage tissues for in vitro studies.

This paper reports a tunable luminescence of europium (Eu 3+) doped zirconia (ZrO2) nanoparticles as a function of hydrothermal temperature, europium concentrations, time and pH value. The nano-sized Eu doped ZrO2 (Eu:ZrO2) particle was synthesized by hydrothermal method at the temperature of 200 °C and time up to 48 h. The nano-sized Eu:ZrO2 particles have a diameter of about 10 nm. The luminescent properties of nano-sized Eu:ZrO2 particle was enhanced in the sample when high temperature, high Eu 3+ concentration and prolonging hydrothermal time were used at pH 7. These results suggest the use of Eu:ZrO2 nanoparticles followed by thermal annealing in tuning the luminescence of Eu:ZrO2 nanoparticles which have potential applications as phosphors in solid state lighting.

Anaerobic co-digestion of primary sludge with two types of drinking water treatment sludge (DWTS), namely iron- or aluminum-rich DWTS (Fe- or Al-DWTS) were systematically evaluated by biochemical methane potential tests, kinetic modelling, downstream process parameters and microbial community analysis. Specific methane yields decreased approximately 19% to 123 mL·g−1 VS, while the hydrolysis constant kh decreased from 0.21 d−1 to 0.18 d−1 for Fe-DWTS at 10% to 40% dosages. On the contrary, specific methane yields decreased 45–55% for Al-DWTS, and kh decreased to 0.14 d−1 at 40% dosage. Significant removals (>95%) of phosphate and hydrogen sulfide were observed for Fe- and Al-DWTS additions at 40% dosage. Microbial community analysis revealed that Al-DWTS increased the abundance of most hydrogenotrophic methanogens, while Fe-DWTS increased the abundance of acetoclastic methanogens. Kinetic modelling further revealed that Fe- and Al-DWTS additions affected the hydrolysis and methanogenesis process kinetics and the methane yield differently.

INTRODUCTION After injuries, the cartilage healing capacity is limited owing to its nature as a particular connective tissue without blood vessels, lymphatics, or nerves. The creation of artificial cartilage tissue mimics the biological properties of native cartilage and can reduce the need for donated tissue. Fibrin is a type of biodegradable scaffold that has great potential in tissue engineering applications. It can become good material for cell adhesion and proliferation in vitro. Therefore, this study aimed to create a cartilage tissue in vitro using umbilical cord-derived mesenchymal stem cells (UCMSC) and growth factor-rich fibrin (GRF) scaffolds. METHODS UCMSCs were isolated and expanded, and platelet-rich plasma (PRP) preparations were performed following previously published protocols. PRP was activated (aPRP) by a 0.45-μm syringe filter to release growth factors inside the platelets. Each 2.105 of the UCMSCs were suspended in 2 ml of aPRP to make the mixture of MSC and PRP (MSC-PRP). Then, Ca2+ solution was added to this mixture to produce the fibril scaffold with UCMSCs inside. UCMSCs' adhesion and proliferation inside the scaffold were evaluated by observation under inverted microscopy, H-E staining, MTT assays, and scanning electron microscopy (SEM). The fibril structure containing UCMSCs was cultured, and chondrogenesis was induced using commercial chondrogenesis media for 21 days (iMSC-GRF). The differentiation in efficacy toward cartilage was evaluated based on the accumulation of aggrecan (acan), glycosaminoglycans (GAGs), and collagen type II (Col II). RESULTS The results showed that we successfully created a cartilage tissue with some characteristics that mimic the properties of natural cartilage. The engineered cartilage tissue was positive with some cartilage protein, such as acan, GAG, and Coll II. In vitro cartilage presented some natural chondrocyte-like cells. The artificial cartilage tissue was positive for CD14, CD34, CD90, CD105, and HLA-DR and negative for CD44, CD45, and CD73. CONCLUSION These results showed that using UCMSCs and growth factor-rich fibril from platelet-rich plasma was feasible to produce engineered cartilage tissue for further experiments or clinical usage.

The distribution of sodium and diffusion mechanism in sodium-silicate melt with various compositions are investigated via molecular dynamics simulation. The microstructure and dynamical characteristic have been studied with the help of Voronoi polyhedron, simplex and Si-O subnet, oxygen-cluster. The simulation results reveal that Na atoms tend to be in the O polyhedrons and not in Si ones. Moreover, the Na atoms are mainly located in non-bridging oxygen (NBO) and free oxygen (FO) polyhedrons. The Voronoi volume of bridging oxygen (BO) or NBO weakly depends on the number of Na located in polyhedron which indicates the strong Si-O bond compared to Na-O bond. The structure of sodium silicate melt consists of two separate regions: the Na-poor regions of Si-BO subnets and a Na-rich region of NBO-FO cluster. The density of sodium in the NBO-FO cluster is by 3–6 times larger than the one of Si-O subnets. This largest NBO-FO cluster represents a diffusion channel for sodium in sodium-silicate. Furthermore, we find that each BO polyhedron contains 0 or 1 Na atom meanwhile each NBO polyhedron contains 1 or 2 Na atoms. Thereby, the BO and NBO polyhedron contains 1 and 2 sites, respectively. The energy for Na atom located in BO site is larger than that in NBO site. The transition energy for Na atom moving from present site to neighboring NBO site is smaller than that to neighboring BO site. So, Na atoms move frequently to neighboring polyhedrons of NBO, and rarely to the BO ones.

In this study, ex-situ Cu-TiC nanocomposites of 1, 3 and 5 vol. % TiC and in-situ Cu-TiH2-C nanocomposites (corresponding to 5 vol. % TiC) were prepared using ball milling and spark plasma sintering methods. Powder mixtures were milled for 4 h at 400 rpm. As-milled Cu-TiC composite powders were consolidated under an applied pressure of 70 MPa. The phase composition, and microstructure of the composite samples were characterized by X-ray diffraction, and scanning electron microscope and transmission electron microscope techniques, respectively. With the increasing TiC content from 1 to 5 vol. %, the hardness of the ex-situ composites when sintered at 600 &deg, C changed between 161.4 and 178.5 HV and the electrical conductivity decreased from 52.1 to 47.6 % IACS. In-situ Cu-TiH2-C nanocomposite sintered at 950 &deg, C had higher hardness and electrical conductivity than ex-situ Cu-TiC composite due to having a homogenous distribution of nano reinforcement particles and dense structure.

Silver nanoparticles (AgNPs) are now being widely used as antibacterial agents due to their strong bactericidal properties and low toxicity on mammalian cells. In this study, γ-rays irradiation method was used to synthesize AgNPs from silver nitrate (AgNO3) solution and to graft acrylic acid (AAc) onto porous polypropylene (PP). Porous PP grafted with AAc (PP-g-AAc) was then immobilized with AgNPs for preparing the antimicrobial materials (PP-g-AAc/AgNPs). The results demonstrated that the grafting yield of AAc onto PP increased by the increasing of irradiation dose as well as AAc concentration. The PP-g-AAc samples with grafting degrees from 1.2 to 29.8% were immobilized with AgNPs (d ~ 10 nm, 500 ppm) to obtain antimicrobial properties. The immobilized Ag contents were from 132 to 392 ppm and corresponded to the PP-g-AAc samples at grafting degrees from 1.2 to 29.8%. The in vitro antibacterial properties of PP-g-AAc/AgNPs materials on E. coli were evaluated and the results indicated that the bactericidal efficiency (η) increased by the increase of Ag contents in the tested materials. The germicidal activities against E. coli of PP-g-AAc/AgNPs containing 363 ppm Ag were found to be nearly 100% after treating in 30 min. In addition, the inhibition zone of this PP-g-AAc/AgNPs on E. coli was also found up to 28 mm in diameter. Thus, γ-rays radiation demonstrated a strong capability in grafting functional groups (AAc) onto porous PP. Furthermore, the porous PP grafted with AAc and immobilized with AgNPs might potentially be used for elimination of bacteria in water filtering.

This article introduces the steps of constructing and using probe to exploit the gene encoding pectinesterase from metagenome DNA sequencing data by next generation gene sequencing tools. Probe was used to exploit and select the gene encoding for pectinesterase from the metagenome DNA sequences of bacteria in goat rumen and thereby select a sequence to express in E. coli. According to the CAZy classification system, pectinesterase belongs to the family of carbohydrates esterases CE8 is an enzyme that has many applications in the food processing industry, environmental treatment, animal feed processing and medicine. As the results, 3 sequences of CE8 was retrieved from CAZy database and one probe was designed, this probe length was 367 amino acids contained all the conserved amino acid residues: 200 conserved residues in all sequence, 72 residues similar in almost sequences and residues conserved in many sequences and homologus; choosed highest alkalinity index. Using the probe designed, we filtered four coding sequences for pectinesterase from metagenome DNA sequencing data of bacteria in goat rumen. Spatial structure estimation with Phyre2 has only one sequencing (code 46301) with 100% sequence identity and 90% query coverage with pectinesterase. A artificial gene were synthesized and inserted into the vector pET22b (+) at the NcoI, XhoI to co-express with chaperone pG-KJE8 in E. coli. The recombinant pectinesterase enzyme is expressed in soluble form and has a pectin substrate biodegradation activity. The results demonstrate that using probe for gene extraction is feasible.

The microstructure of lead silicate melt (Pb2SiO4) and its change under high pressure are investigated by molecular dynamics simulation. The models are constructed at temperature of 3000 K and in the 0–50 GPa pressure range. The microstructural correlate of pair radial distribution functions is clarified. Short range order (SRO) and intermediate range order (IRO) are investigated via topology analysis of SiOx units and SiOx-clusters. Microstructural analysis, cluster-analysis and visualization techniques are applied to clarify the characteristics of -Si-O- network structure. The local environment around Pb+2, Si+4 and O−2 ions, incorporation mechanism of Pb2+ cations into -Si-O- network, the microphase separation under compression have been clarified. Specially, the storage mechanism of hazardous metal ions (heavy metal ions in industrial and nuclear wastes) in silica-based multicomponent oxide systems is also discussed in detail.

Although diurnal variations have been observed in tear film parameters in various species, the molecular mechanisms that control circadian tear secretion remain unclear. The aim of our study was to evaluate the role of clock genes in the lacrimal gland (LG) in regulation of tear secretion. Tear volume was measured by cotton thread test in core clock genes deficient (Cry1−/− Cry2−/−-) mice which are behaviorally arrhythmic. Real-time quantitative RT-PCR was used to examine expression profiles of core clock genes in the LG including Per1, Per2, Per3, Clock, Bmal1. All experiments were performed under a 12 h of light and 12 h of darkness (LD) and constant dark (DD) conditions. Under both LD and DD conditions, diurnal and circadian rhythms were observed in tear secretion of wild-type mice with tear volume increased in the objective and subjective night while disruption in diurnal and circadian variations of tear secretion were found in Cry1−/− Cry2−/−-mice. In wild-type mice, the expression level of major clock genes in the LG showed oscillatory patterns under both LD and DD conditions. In contrast, expression clock genes in the lacrimal gland of Cry1−/− Cry2−/−- mice showed complete loss of oscillation regardless of environmental light conditions. These findings confirmed the presence of diurnal and circadian rhythms of tear secretion and provided evidences supporting a critical role for the clock in the control of tear secretion.

In this paper, selective laser sintering (SLS) was applied to join two materials by printing Ti–6Al–4V powder on a Ti substrate without any support parts. The characteristics of the interface between the as-built Ti–6Al–4V sample and the substrate were investigated. The analysis indicates that a heat-affected zone (HAZ) and the fish-scale type were formed at the joining area. The combination of smaller grains, acicular [Formula: see text] martensite, and lamellar [Formula: see text] structures was observed inside the interface zone. The hardness value at the interface area was measured by about 320 HV which is higher than 280 HV of the substrate and smaller than 369 HV of the as-built sample. The results predict that the SLS process is a promising method for manufacturing of hybrid materials.

Anaerobic digestion technology (biogas) has been used to treat husbandry wastes in the Mekong Delta of Vietnam for more than 30 years. However, biogas applications are limited. One major barrier is lack of input material for biogas digesters, because husbandry is normally conducted at the household scale. In contrast, rice straw (RS) is available in huge quantities in the Mekong Delta, but it is seldom put to use. This study tested the suitability and efficiency of anaerobic co-digestion of RS and pig manure (PM) to produce biogas. The study used 21-L lab-scale batches of anaerobic co-digestion of PM and RS, testing different sizes of RS. The mixing ratio for co-digestion was 50:50 based on organic dry matter values of input materials. The results showed that temperature, pH, alkalinity, and redox potential of almost all RS sizes were in the suitable range for activities of methanogenic microorganisms. The biogas yields per kilogram of fermented organic dry matter for the treatments were, for 1.0 cm RS, 691.05 L; 10.0 cm, 687.79 L; 20.0 cm, 685.08 L; and original RS size (uncut), 680.44 L. These values did not significantly differ from that of the 100% PM treatment. The methane content tended to increase with time, starting with the second week, and was well qualified for energy use. Our results strongly confirm that RS can be added to PM to produce biogas and that chopping RS is unnecessary.

Scope Resveratrol is a natural occurring polyphenol with several health promoting activities, including anticancer potential. Here, we analyzed the cytotoxic effects of resveratrol against malignant cells characterized by aberrant activation of the Janus kinase 2 (JAK2). Methods and results Cell-cycle analysis, proliferation, apoptosis, and Western blotting assays were performed to study the effect of resveratrol on malignant cells exhibiting an excessive activation of the JAK2 pathway secondary to the JAK2V617F mutation. Resveratrol inhibited proliferation and induced apoptosis in JAK2V617F mutant tumor cells and its selectivity was 1.5–6.9 times greater than that observed in other tumor cells without the JAK2V617F mutation. In addition, resveratrol inhibited the phosphorylation of JAK1, JAK2, and Tyk2 and their downstream mediators, including STAT3 and STAT5. In primary cultures, resveratrol treatment inhibited erythroid progenitor colony formation in blood samples obtained from JAK2V617F polycythemia vera patients. Moreover, resveratrol synergized with the selective JAK2 inhibitor ruxolitinib, eliminating tumor cells with the JAK2 mutation. Conclusion Resveratrol may have therapeutic potential against myeloproliferative neoplasms associated with the aberrant activation of the JAK2 pathway.

In this study, a segmented p-type leg of doped misfit-layered cobaltite Ca_(2.8)Lu_(0.15)Ag_(0.05)Co_4O_(9+δ) and half-Heusler Ti_(0.3)Zr_(0.35)Hf_(0.35)CoSb_(0.8)Sn_(0.2) alloy was fabricated and characterized. The thermoelectric properties of single components, segmented leg, and the electrical contact resistance of the joint part were measured as a function of temperature. The output power generation characteristics of segmented legs were characterized in air under various temperature gradients, ΔT, with the hot side temperature up to 1153 K. At ΔT ≈ 756 K, the maximum conversion efficiency reached a value of ∼5%, which is about 65% of that expected from the materials without parasitic losses. The long-term stability investigation for two weeks at the hot and cold side temperatures of 1153/397 K shows that the segmented leg has good durability as a result of stable and low electrical resistance contacts.

Self-assembly of Aβ peptides into amyloid aggregates has been suggested as the major cause of Alzheimer's disease (AD). Nowadays, there is no medication for AD, but experimental data indicate that reversion of the process of amyloid aggregation reduces the symptoms of disease. In this paper, all 8000 tripeptides were studied for their ability to destroy Aβ fibrils. The docking method and the more sophisticated MM-PBSA (molecular mechanics Poisson-Boltzmann surface area) method were employed to calculate the binding affinity and mode of tripeptides to Aβ fibrils. The ability of these peptides to depolymerize Aβ fibrils was also investigated experimentally using atomic force microscopy and fluorescence spectroscopy (Thioflavin T assay). It was shown that tripeptides prefer to bind to hydrophobic regions of 6Aβ9-40 fibrils. Tripeptides WWW, WWP, WPW and PWW were found to be the most potent binders. In vitro experiments showed that tight-binding tripeptides have significant depolymerizing activities and their DC50 values determined from dose-response curves were in micromolar range. The ability of nonbinding (GAM, AAM) and weak-binding (IVL and VLA) tripeptides to destroy Aβ fibrils was negligible. In vitro data of tripeptide depolymerizing activities support the predictions obtained by molecular docking and all-atom simulation methods. Our results suggest that presence of multiple complexes of heterocycles forming by tryptophan and proline residues in tripeptides is crucial for their tight binding to Aβ fibrils as well as for extensive fibril depolymerization. We recommend PWW for further studies as it has the lowest experimental binding constant.

The scarcity of enzymes having an optimal activity in lignocellulose deconstruction is an obstacle for industrial-scale conversion of cellulosic biomass into biofuels. With the aim of mining novel lignocellulolytic enzymes, a ~9 Gb metagenome of bacteria in Vietnamese native goats’ rumen was sequenced by Illumina platform. From the data, 821 ORFs encoding carbohydrate esterases (CEs) and polysaccharide lyases (PLs) serving for lignocellulose pre-treatment, 816 ORFs encoding 11 glycoside hydrolase families (GHs) of cellulases, and 2252 ORFs encoding 22 GHs of hemicellulases, were mined. The carbohydrate binding module (CBM) was also abundant with 763 ORFs, of which 480 ORFs are located with lignocellulolytic enzymes. The enzyme modularity analysis showed that CBMs are usually present in endoglucanase, endo 1,3-beta-D-glucosidase, and endoxylanase, whereas fibronectin 3-like module (FN3) mainly represents in GH3 and immunoglobulin-like domain (Ig) was located in GH9 only. Every domain located in each ORF was analyzed in detail to contribute enzymes’ modularity which is valuable for modelling, to study the structure, and for recombinant production. With the aim of confirming the annotated results, a mined ORF encoding CBM63 was highly expressed in E. coli in soluble form. The purified recombinant CBM63 exhibited no cellulase activity, but enhanced a commercial cellulase activity in the destruction of a paper filter.

Fourier transform large amplitude alternating current voltammetry (FTACV) studies are reported on an electrocatalytic (EC') mechanistic system which exhibits split wave behavior on both macro- and micro-size working electrodes. The electrochemical characteristics of the EC' mechanism were analysed using the fundamental to fourth harmonic components deduced by the Fourier transform algorithm. The effects of the sinusoidal frequencies of the applied potential, electrode geometry and substrate concentrations are investigated. The split wave phenomenon was observed and explored particularly.

Al-Fe-Y amorphous alloys of Al84Fe16, Al82Fe18 and Al82Fe16Y2 composition were prepared by mechanical alloying in a planetary ball mill P100. A nearly complete amorphization could be achieved for the Al84Fe16, Al82Fe18 and Al82Fe16Y2 powder alloys after 100h of milling at a rotational speed of 350 rpm in hexane medium. Differential scanning calorimetry (DSC) analyses revealed three-stage crystallization processes for Al82Fe18 and Al82Fe16Y2 alloys and four-stage crystallization processes for Al84Fe16 alloy, respectively. Taking into account the DSC data, the thermal stability increased in the order of Al84Fe16, Al82Fe18, and Al82Fe16Y2 composition. The Al82Fe16Y2 alloy exhibited a relatively better thermal stability than the other two alloys.

A dense yttria stabilized zirconia (YSZ)-carbonate membrane that was impermeable to gas at low temperature became highly permeable to CO2 at temperature above the melting point of the carbonate. The CO2 permeance across the YSZ-molten carbonate dual-phase membrane was observed to be higher than 0.1 × 10−8 mol/m2/Pa/s at temperature >650 °C. The movement of ions was promoted at high temperature as YSZ and molten carbonate became highly conductive to oxygen ions and carbonate species, respectively. Addition of poly(methyl methacrylate) (PMMA) during preparation of macroporous YSZ support created interconnected pore structures that were found conducive for carbonate infiltration and integration with the membrane materials.

Spin-polarized density functional theory studies of hydrogen sulfide (H2S) adsorption and decomposition on Ni(100) and Ni3Al(100) surfaces were conducted to understand the aluminum (Al) alloying effect on H2S dissociation. For such purpose, we first determined the near surface structure of fully ordered Ni3Al alloy along the [100] direction by calculating the Al segregation energy to the surface and then examined the adsorption energies of the adsorbates (H2S, HS, S, and H) and the activation barriers for the H2S and HS decomposition by using Climbing Image-Nudged Elastic Band method. We found that regardless of the way to terminate the surface, Al atom in bimetallic Ni3Al(100) tends to exist in the first surface layer, rather than in the second or third layer, and the Ni3Al(100) surface can substantially retard the H2S decomposition by reducing the adsorption energy of sulfur compounds compared to the pure Ni(100) case. Finally, we presented how the Al in Ni3Al modifies the activity of surface Ni atoms toward the sulfur compounds by calculating the local density of states and charge distribution in alloying components. This work hints the importance of knowing how to properly tailor the reactivity of Ni based materials to enhance the resistance for sulfur poisoning.

The self-assembly of the amyloid beta (Aβ) peptides into senile plaques is the hallmark of Alzheimer's disease. Recent experiments have shown that the English familial disease mutation (H6R) speeds up the fibril formation process of alloforms Aβ40 and Aβ42 peptides altering their toxicity to cells. We used all-atom molecular dynamics simulations at microsecond time scales with the OPLS-AA force field and TIP4P explicit water model to study the structural dynamics of the monomer and dimer of H6R sequences of both peptides. The reason behind the self-assembly acceleration is common that upon mutation the net charge is reduced leading to the weaker repulsive interaction between chains that facilitates the peptide association. In addition, our estimation of the solvation free energy shows that the mutation enhances the hydrophobicity of both peptides speeding up their aggregation. However, we can show that the acceleration mechanisms are different for different peptides: the rate of fibril formation of Aβ42 increases due to increased β-structure at the C-terminal in both monomer and dimer and enhanced stability of salt bridge Asp23-Lys28 in monomer, while the enhancement of turn at residues 25-29 and reduction of coil in regions 10-13, 26-19, and 30-34 would play the key role for Aβ40. Overall, our study provides a detailed atomistic picture of the H6R-mediated conformational changes that are consistent with the experimental findings and highlights the important role of the N-terminal in Aβ peptide aggregation.

The influence of water models SPC, SPC/E, TIP3P, and TIP4P on ligand binding affinity is examined by calculating the binding free energyΔGbindof oseltamivir carboxylate (Tamiflu) to the wild type of glycoprotein neuraminidase from the pandemic A/H5N1 virus.ΔGbindis estimated by the Molecular Mechanic-Poisson Boltzmann Surface Area method and all-atom simulations with different combinations of these aqueous models and four force fields AMBER99SB, CHARMM27, GROMOS96 43a1, and OPLS-AA/L. It is shown that there is no correlation between the binding free energy and the water density in the binding pocket in CHARMM. However, for three remaining force fieldsΔGbinddecays with increase of water density. SPC/E provides the lowest binding free energy for any force field, while the water effect is the most pronounced in CHARMM. In agreement with the popular GROMACS recommendation, the binding score obtained by combinations of AMBER-TIP3P, OPLS-TIP4P, and GROMOS-SPC is the most relevant to the experiments. For wild-type neuraminidase we have found that SPC is more suitable for CHARMM than TIP3P recommended by GROMACS for studying ligand binding. However, our study for three of its mutants reveals that TIP3P is presumably the best choice for CHARMM.

Recent experiments have shown that the mutation Tottori (D7N) alters the toxicity, assembly and rate of fibril formation of the wild type (WT) amyloid beta (Aβ) Aβ40 and Aβ42 peptides. We used all-atom molecular dynamics simulations in explicit solvent of the monomer and dimer of both alloforms with their WT and D7N sequences. The monomer simulations starting from a random coil and totaling 3 μs show that the D7N mutation changes the fold and the network of salt bridges in both alloforms. The dimer simulations starting from the amyloid fibrillar states and totaling 4.4 μs also reveal noticeable changes in terms of secondary structure, salt bridge, and topology. Overall, this study provides physical insights into the enhanced rate of fibril formation upon D7N mutation and an atomic picture of the D7N-mediated conformational change on Aβ40 and Aβ42 peptides.

Nickel aluminum (Ni–Al) alloy anodes have become the preferred choice in anode material and have received widespread attention in molten carbonate fuel cell (MCFC) research due to their high durability and effectiveness in resisting creep of stack loadings. They are, however, susceptible to hydrogen sulfide (H2S) poisoning, which results in pore compression and rapid reduction of active sites for the electro-catalytic reaction. In this work, iron is introduced into a conventional Ni–Al anode to improve the creep resistance and tolerance to H2S. Anodes containing 30 wt.% Fe have a low creep strain of ca. 3%, but their creep resistance is much better than that of standard anodes. Single cells operated stably over 1000 h with a low voltage loss of ca. 5 mV. When exposed to H2S, the modified anode exhibited excellent recovery from the poisoning effect.

International audience; The cavitation of gas bubbles in liquids has been applied to different disciplines in life and natural sciences, and in technologies. To obtain an appropriate theoretical description of effects induced by the bubble cavitation, we develop an all-atom nonequilibrium molecular-dynamics simulation method to simulate bubbles undergoing harmonic oscillation in size. This allows us to understand the mechanism of the bubble cavitation-induced liquid shear stress on surrounding objects. The method is then employed to simulate an A beta fibril model in the presence of bubbles, and the results show that the bubble expansion and contraction exert water pressure on the fibril. This yields to the deceleration and acceleration of the fibril kinetic energy, facilitating the conformational transition between local free energy minima, and leading to the dissociation of the fibril. Our work, which is a proof-of-concept, may open a new, efficient way to dissociate amyloid fibrils using the bubble cavitation technique, and new venues to investigate the complex phenomena associated with amyloidogenesis. Published by AIP Publishing.

The effects of beta-sheet breaker peptides KLVFF and LPFFD on the oligomerization of amyloid peptides were studied by all-atom simulations. It was found that LPFFD interferes the aggregation of Aβ(16-22) peptides to a greater extent than does KLVFF. Using the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method, we found that the former binds more strongly to Aβ(16-22). Therefore, by simulations, we have clarified the relationship between aggregation rates and binding affinity: the stronger the ligand binding, the slower the oligomerization process. The binding affinity of pentapeptides to full-length peptide Aβ(1-40) and its mature fibrils has been considered using the Autodock and MM-PBSA methods. The hydrophobic interaction between ligands and receptors plays a more important role for association than does hydrogen bonding. The influence of beta-sheet breaker peptides on the secondary structures of monomer Aβ(1-40) was studied in detail, and it turns out that, in their presence, the total beta-sheet content can be enhanced. However, the aggregation can be slowed because the beta-content is reduced in fibril-prone regions. Both pentapeptides strongly bind to monomer Aβ(1-40), as well as to mature fibrils, but KLVFF displays a lower binding affinity than LPFFD. Our findings are in accord with earlier experiments that both of these peptides can serve as prominent inhibitors. In addition, we predict that LPFFD inhibits/degrades the fibrillogenesis of full-length amyloid peptides better than KLVFF. This is probably related to a difference in their total hydrophobicities in that the higher the hydrophobicity, the lower the inhibitory capacity. The GROMOS96 43a1 force field with explicit water and the force field proposed by Morris et al. (Morris et al. J. Comput. Chem. 1998, 19, 1639 ) were employed for all-atom molecular dynamics simulations and Autodock experiments, respectively.

Since March 2009, the rapid spread of infection during the recent A/H1N1 swine flu pandemic has raised concerns of a far more dangerous outcome should this virus become resistant to current drug therapies. Currently oseltamivir (tamiflu) is intensively used for the treatment of influenza and is reported effective for 2009 A/H1N1 virus. However, as this virus is evolving fast, some drug-resistant strains are emerging. Therefore, it is critical to seek alternative treatments and identify roots of the drug resistance. In this paper, we use the steered molecular dynamics (SMD) approach to estimate the binding affinity of ligands to the glycoprotein neuraminidase. Our idea is based on the hypothesis that the larger is the force needed to unbind a ligand from a receptor the higher its binding affinity. Using all-atom models with Gromos force field 43a1 and explicit water, we have studied the binding ability of 32 ligands to glycoprotein neuraminidase from swine flu virus A/H1N1. The electrostatic interaction is shown to play a more important role in binding affinity than the van der Waals one. We have found that four ligands 141562, 5069, 46080, and 117079 from the NSC set are the most promising candidates to cope with this virus, while peramivir, oseltamivir, and zanamivir are ranked 8, 11, and 20. The observation that these four ligands are better than existing commercial drugs has been also confirmed by our results on the binding free energies obtained by the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method. Our prediction may be useful for the therapeutic application.

Kinetic measurement of protein folding is limited by the method used to trigger folding. Traditional methods, such as stopped flow, have a long mixing dead time and cannot be used to monitor fast folding processes. Here, we report a compound, 4-(bromomethyl)6,7-dimethoxycoumarin, that can be used as a ‘‘photolabile cage’’ to study the early stages of protein folding. The folding process of a protein, RD1, including kinetics, enthalpy, and volume change, was studied by the combined use of a phototriggered caging strategy and time-resolved photoacoustic calorimetry. The cage caused unfolding of the photolabile protein, and then a pulse UV laser (� 10 29 s) was used to break the cage, leaving the protein free to refold and allowing the resolving of two folding events on a nanosecond time scale. This strategy is especially good for monitoring fast folding proteins that cannot be studied by traditional methods.

Recently, mid-infrared free-electron laser technology has been developed to dissociate amyloid fibrils. Here, we present a theoretical framework for this type of experiment based on laser-induced nonequilibrium all-atom molecular dynamics simulations. We show that the fibril is destroyed due to the strong resonance between its amide I vibrational modes and the laser field. The effects of laser irradiation are determined by a balance between fibril formation and dissociation. While the overall rearrangements of the fibril finish over short time scales, the interaction between the peptides and the solvent continues over much longer times indicating that the waters play an important role in the dissociation process. Our results thus provide new insights into amyloid fibril dissociation by laser techniques and open up new venues to investigate the complex phenomena associated with amyloidogenesis.

The main concerns of biomolecular dynamics simulations are the convergence of the conformational sampling and the dependence of the results on the force fields. While the first issue can be addressed by employing enhanced sampling techniques such as simulated tempering or replica exchange molecular dynamics, repeating these simulations with different force fields is very time consuming. Here, we propose an automatic method that includes different force fields into a single advanced sampling simulation. Conformational sampling using three all-atom force fields is enhanced by simulated tempering and by formulating the weight parameters of the simulated tempering method in terms of the energy fluctuations, the system is able to perform random walk in both temperature and force field spaces. The method is first demonstrated on a 1D system and then validated by the folding of the 10-residue chignolin peptide in explicit water.

Self-assembled functional peptide biomaterials are emerging with a wide range of envisioned applications in the field of nanotechnology. Currently, methods and tools have been developed to control and manipulate as well as to explore new properties of self-assembled structures. However, considerably fewer studies are being devoted to developing efficient methods to degrade or recycle such extremely stable biomaterials. With this in mind, here we suggest a theoretical framework, inspired by the recent developed mid-infrared free-electron laser pulse technology, to dissociate peptide nanotubes. Adopting a diphenylalanine channel as a prototypical example, we find that the primary step in the dissociation process occurs due to the strong resonance between the carboxylate bond vibrations of the diphenylalanine peptides and the tuned laser frequencies. The effects of laser irradiation are determined by a balance between tube formation and dissociation. Our work shows a proof of concept and should provide a motivation for future experimental developments with the final aim to open a new and efficient way to cleave or to recycle bio-inspired materials.

Vitamin A deficiency is one of the major nutritional deficiencies in Vietnam. the first survey, conducted in 1985–1988 showed that the prevalence of severe xerophthalmia was seven times higher than the cutoff point established by the World Health Organization (WHO) to define vitamin A deficiency as a public health problem. the result of this survey strongly convinced the government to launch a program to control vitamin A deficiency, which started in 1988. the program strategies included nutrition education, universal distribution of high-dose vitamin A capsules to children aged 6 to 36 months in combination with national immunization days, and promotion of production and consumption of vitamin A–rich foods at the family level. the implementation network was set up based on the existing preventive health structure at all administrative levels. Organizations such as the women's union and other social sectors have participated actively in the program. Surveys conducted in 1994 and 1998 showed that the prevalence of clinical xerophthalmia was significantly lower than that identified in the baseline survey and below the WHO criteria for a public health problem. the achievements of our program have demonstrated that an effective vitamin A supplementation program can be implemented successfully by the preventive health network with active community participation. in the coming years, it will be important for our program to develop approaches other than vitamin A supplementation in order to maintain the past achievements.

Centre of Pharmaceutical Research-Training, Vietnam Military Medical University, 160 Phung Hung, Hadong, Hanoi, Vietnam College of Pharmacy, Catholic University of Daegu, Gyeongbuk 712-702, Korea. E-mail: bsmin@cu.ac.kr Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Caugiay, Hanoi, Vietnam Deparment of Pharmacognosy, Hanoi University of Pharmacy, 15 Le Thanh Tong, Hoankiem, Hanoi, Vietnam Faculty of Food Science and Biotechnology, Pukyung National University, Busan 608-737, Korea College of Pharmacy, Kyungpook National University, Daegu 702-701, Korea Received November 14, 2013, Accepted November 27, 2013

Recent experiments have shown that the Taiwan mutation (D7H) slows the fibril formation of amyloid peptides Aβ40 and Aβ42. Motivated by this finding, we have studied the influence of D7H mutation on structures of Aβ peptide monomers using the replica exchange molecular dynamics simulations with OPLS force field and implicit water model. Our study reveals that the mechanism behind modulation of aggregation rates is associated with decrease of β-content and dynamics of the salt bridge D23-K28. Estimating the bending free energy of this salt bridge, we have found that, in agreement with the experiments, the fibril formation rate of both peptides Aβ40 and Aβ42 is reduced about two times by mutation.

A new alkenylphenol, bavinol A (1), together with six known compounds (2–7) were isolated from the aerial parts of Piper bavinum (Piperaceae). The chemical structures of these compounds were determined by spectroscopic analyses including 2D NMR spectroscopy. The anti-Alzheimer effects of compounds 1–7 were evaluated from acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity assays. Bavinol A (1), ampelopsin (3), and violanthin (4) exhibited AChE inhibitory activities with IC50 values of 29.80, 59.47 and 79.80 μM. Compound 1 also showed the most potent BChE inhibitory activity with an IC50 value of 19.25 μM.

By the virtual screening method we have screened out Dihydrochalcone as a top-lead for the Alzheimer's disease using the database of about 32364 natural compounds. The binding affinity of this ligand to amyloid beta (Aβ) fibril has been thoroughly studied by computer simulation and experiment. Using the Thioflavin T (ThT) assay we have obtained the inhibition constant IC50 μM. This result is in good agreement with the estimation of the binding free energy obtained by the molecular mechanic-Poisson Boltzmann surface area method and all-atom simulation with the force field CHARMM 27 and water model TIP3P. Cell viability assays indicated that Dihydrochalcone could effectively reduce the cytotoxicity induced by Aβ. Thus, both in silico and in vitro studies show that Dihydrochalcone is a potential drug for the Alzheimers disease.

Solid oxide fuel cells (SOFCs) with lanthanum strontium cobalt ferrite (LSCF) cathodes often employ a samaria-doped or gadolinia-doped ceria (SDC or GDC, respectively) barrier layer between the cathode and the yttria-stabilized zirconia (YSZ) electrolyte to inhibit Sr from migrating to the YSZ surface where it reacts to form electrically-resistive strontium zirconate during cathode sintering. Because the SDC must be sintered at limited temperatures (generally ≤1200°C) to avoid forming a CeO2-ZrO2 solid solution that has significantly lower ionic conductivity, screen printed barrier layers are often porous after firing. Electrochemical tests of cells with dense, continuous pulsed laser deposited (PLD) SDC found that these cells exhibited significantly higher performance than those with the conventional screen-printed porous SDC layers. Thus, PNNL began investigating the fabrication of dense, continuous SDC barrier layers using cost-effective deposition by screen printing which is amenable to industrial production of SOFCs. Many approaches to improve the SDC density have been explored including the use of powder with reduced particle sizes, inks with increased solids loading, and doping with sintering aids. While some of these tests were successful in enhancing the density of the SDC, the stresses induced by constrained sintering on the surface of previously-fired YSZ caused cracks and discontinuities in the SDC barrier layer. These results together with steps that have been taken to address the constrained sintering issue will be presented.

Effects of amyloid beta (Aβ) peptide Aβ(40) on secondary structures of Aβ(42) are studied by all-atom simulations using the GROMOS96 43a1 force field with explicit water. It is shown that in the presence of Aβ(40) the beta-content of monomer Aβ(42) is reduced. Since the fibril-prone conformation N∗ of full-length Aβ peptides has the shape of beta strand-loop-beta strand this result suggests that Aβ(40) decreases the probability of observing N∗ of Aβ(42) in monomer state. Based on this and the hypothesis that the higher is the population of N∗ the higher fibril formation rates, one can expect that, in agreement with the recent experiment, Aβ(40) inhibit fibril formation of Aβ(42). It is shown that the presence of Aβ(40) makes the salt bridge D23-K28 and fragment 18-33 of Aβ(42) more flexible providing additional support for this experimental fact. Our estimation of the binding free energy by the molecular mechanics-Poisson-Boltzmann surface area method reveals the inhibition mechanism that Aβ(40) binds to Aβ(42) modifying its morphology.