Large Molecular Weight Research Articles

INVESTIGATION OF THE EFFECTIVENESS OF USING WHEY POWDER TO REDUCE THE TOXICITY OF THE WATER/ALCOHOL MIXTURE

A promising way of reducing the toxicity of ethanol is purifying the water/alcohol mixture with sorbents. This paper proves the effectiveness of the method when prepared whey powder is used to remove toxic elements from a water/alcohol mixture. In the test samples, the mass concentration of toxic substances (methyl acetate, ethyl acetate, methanol) was determined by high-performance gas chromatography. It has been established how the effectiveness of purifying the alcohol/water mixture depends on the amount of the sorbent added and on the resting duration. The amount of the sorbent was 3–9 kg per 1000 dal, when calculated as whey powder, and the resting time was 1–5 hours. The maximum decrease in toxic substances was observed when prepared whey (whey powder equivalent) was added in the amount 6.0±1.0 kg per 1000 dal, with 3 hours’ resting. Under these purification conditions, the mass concentration of aldehydes in the water/alcohol mixture was reduced by 30%, the volume fraction of methanol by 27%, the mass concentration of esters by more than 70%, and the concentration of fusel oil did not exceed the detection threshold. The toxic substances decrease due to the coagulation of whey protein with quite a branched surface, which is accompanied by the sorption of toxic substances dissolved in the water/alcohol mixture, especially of those with a large molecular weight. These toxic components are the ones that can reduce the quality of raw materials and degrade the sensory properties. Purification of the water/alcohol mixture, when toxic compounds are removed with the help of prepared whey powder, improves the sensory characteristics. A sample purified with milk whey has a softer and more rounded flavour and a characteristic shine. The use of prepared whey as a sorbent to purify the water/alcohol mixture allows obtaining a low-toxic product with improved sensory properties.

The Role of CYP3A in Health and Disease.

CYP3A is an enzyme subfamily in the cytochrome P450 (CYP) superfamily and includes isoforms CYP3A4, CYP3A5, CYP3A7, and CYP3A43. CYP3A enzymes are indiscriminate toward substrates and are unique in that these enzymes metabolize both endogenous compounds and diverse xenobiotics (including drugs); almost the only common characteristic of these compounds is lipophilicity and a relatively large molecular weight. CYP3A enzymes are widely expressed in human organs and tissues, and consequences of these enzymes' activities play a major role both in normal regulation of physiological levels of endogenous compounds and in various pathological conditions. This review addresses these aspects of regulation of CYP3A enzymes under physiological conditions and their involvement in the initiation and progression of diseases.

Developing potent BTKC481S PROTACs for ibrutinib-resistant malignant lymphoma

Ibrutinib is a first-line treatment drug for B-cell malignancies. However, resistance to ibrutinib has been reported due to BTKC481S mutation. Although PROTAC strategy is expected to overcome this clinical resistance, it has limitations such as large molecular weight and moderate bioactivity, which restrict its potential clinical application. Herein, we report a new type of potent BTKC481S-targeting PROTAC degrader. Through design, computer-assisted optimization and SAR studies, we have developed a representative BTKC481S degrader L6 with a much smaller molecular weight and improved solubility. Notably, L6 demonstrates better BTK degrading activity and lower IC50 value in ibrutinib-resistant cell line than the first-generation BTK degrader P13I. Optimization strategy of L6 provides a general approach in the development of PROTACs targeting BTK and other proteins for future study.

Structural characterization and in vitro antioxidant and hypoglycemic activities of degraded polysaccharides from sweet corncob

Polysaccharides have received increasing attention due to their bioactivity. Sweet corncob is a subsidiary agricultural product, not widely utilized. Previous studies successfully isolated polysaccharides from sweet corncob (SCP). However, the large molecular weight limited their function. In the present study, degraded SCP with four different β-amylase concentrations (50, 100, 200, and 300 U/mL) was prepared by an ultrasonic-assisted degradation method and named DSCP1, DSCP2, DSCP3 and DSCP4. The results showed that the molecular weights were markedly reduced. Furthermore, the degraded polysaccharides were analyzed using ultraviolet spectroscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray diffraction analysis, Congo red test, scanning electron microscope analysis, and rheological test. It demonstrated minor changes in the glycosidic linkage, but the primary structure was not changed. In addition, the degraded polysaccharides showed better antioxidant and hypoglycemic activities in vitro, and the activity increased in four degraded polysaccharides compared to that of SCP. It can also be easily observed that DSCP3 showed the highest activity. Overall, this is a promising strategy to improve the biological activities of SCP, and DSCP3 can be used as a functional agent as a better antioxidant and glucose-reducing agent.

Bio-Based Adhesives for Orthopedic Applications: Sources, Preparation, Characterization, Challenges, and Future Perspectives

Bone fracture healing involves complex physiological processes that require biological events that are well coordinated. In recent decades, the process of fracture healing has been upheld through various treatments, including bone implants and bio-adhesive utilization. Bio-adhesion can be interpreted as the process in which synthetic or natural materials adhere to body surfaces. Bio-based adhesives have superiority in many value-added applications because of their biocompatibility, biodegradability, and large molecular weight. The increased variety and utilization of bio-based materials with strong adhesion characteristics provide new possibilities in the field of orthopedics in terms of using bio-based adhesives with excellent resorbability, biocompatibility, ease of use, and low immunoreactivity. The aim of this review is to provide comprehensive information and evaluation of the various types of bio-based adhesives used clinically with a specific focus on their application in orthopedics. The main properties of bio-based adhesives, their benefits, and challenges compared with the traditional bio-based materials in orthopedics, as well as the future perspectives in the field, have also been outlined and discussed.

Speciation analysis and formation mechanism of iron-phosphorus compounds during chemical phosphorus removal process

Iron (Fe) salt was applied extensively to remove phosphorus (P) in wastewater treatment plants (WWTPs). Exploring the formation mechanism of iron-phosphorus compounds (FePs) during the chemical P removal (CPR) process is beneficial to P recovery. In this study, the performance of P removal, FePs speciation analysis and the kinetics of P removal under different conditions (pH, Fe/P molar ratio (Fe/Pmol), type of Fe salt, dissolved organic matters) were comprehensively investigated. More than 95% of P was removed under the optimal conditions with pH = 4.7, Fe/Pmol = 2, FeCl3 or polymeric ferric sulfate (PFS) as the coagulant. The FePs formation mechanism was considerably influenced by reaction conditions. Iron-phosphate compounds were the dominant FePs species (>76%) at pH < 6.2, while more iron oxides were formed at pH ≥ 6.2 with decreased P removal efficiency. When the initial Fe/Pmol was 2, iron-phosphate compound was the only product that was formed by the reaction between PO43− and Fe(III) or Fe(II) ions directly. More iron oxides were generated when the initial Fe/Pmol was 1 or 3. At Fe/Pmol = 1, the Fe(III) was hydrolyzed to form iron oxides and trapped PO43−, while at Fe/Pmol = 3, iron-phosphate compounds were produced firstly and the remaining Fe(III) was hydrolyzed to form iron oxides. The pseudo-second-order kinetic model simulated the chemical P removal process well. The reaction rate of P with Fe(II) was slower than that with Fe(III), but complete removal was still achieved when the reaction time was more than 30 min. Poly-Fe salt exhibited a fast P removal rate, while the removal efficiency depended on its iron content. Organic matters in wastewater with large molecular weight and multiple functional groups (such as humic acids) inhibited P removal rate but hardly affect the removal amount. This study provides an insight into CPR by Fe salts and is beneficial for P recovery in WWTPs.

Linear viscoelastic shear and bulk relaxation moduli in poly(tetramethylene oxide) (PTMO) using united-atom molecular dynamics

A quantitative understanding and prediction of the viscoelastic relaxation behavior of polymer melts is required to build up predictive multiscale models, which can be utilized for the practical design of viscoelastic materials. We report the application of the Green–Kubo method to compute the common shear relaxation modulus and the rarely reported bulk relaxation modulus for a realistic united atom model of poly(tetramethylene oxide) (PTMO), which is one key components of the segmented polyurethane (PU) elastomers. The temperature and molecular weight dependent viscoelastic behavior is investigated in detail by computing the bulk relaxation modulus K(t) along with shear relaxation modulus G(t). Our results provide new rheological data for PTMO melt based on the united atom model, which incorporates the chemical details of the polymer backbone. The predicted stress relaxation are mapped onto master curves using the time–temperature superposition principle with horizontal and vertical shift factors. The computed shift factors agree with the Williams–Landel–Ferry equation and appear to be similar for the shear and bulk relaxation modulus. The underlying dynamics for the shear and bulk relaxation modulus appear to stem from the same mechanistic origin as both processes seem to sample similar kinetic signature of the reference time scale of the underlying thermally activated processes in the liquid. Our results demonstrate furthermore, that MD simulations with the chemical details beyond coarse-grained models can sample the Rouse dynamics and the transitions towards entanglement, which is evident by the emergence of a plateau in shear relaxation modulus and scaling relations in the diffusion behavior of the monomer at larger molecular weights.

Oxygen availability regulates the quality of soil dissolved organic matter by mediating microbial metabolism and iron oxidation

Dissolved organic matter (DOM) plays a vital role in biogeochemical processes and in determining the responses of soil organic matter (SOM) to global change. Although the quantity of soil DOM has been inventoried across diverse spatio-temporal scales, the underlying mechanisms accounting for variability in DOM dynamics remain unclear especially in upland ecosystems. Here, a gradient of SOM storage across 12 croplands in northeast China was used to understand links between DOM dynamics, microbial metabolism, and abiotic conditions. We assessed the composition, biodegradability, and key biodegradable components of DOM. In addition, SOM and mineral-associated organic matter (MAOM) composition, soil enzyme activities, oxygen availability, soil texture, and iron (Fe), Fe-bound organic matter, and nutrient concentrations were quantified to clarify the drivers of DOM quality (composition and biodegradability). The proportion of biodegradable DOM increased exponentially with decreasing initial DOM concentration due to larger fractions of depolymerized DOM that was rich in small-molecular phenols and proteinaceous components. Unexpectedly, the composition of DOM was decoupled from that of SOM or MAOM, but significantly related to enzymatic properties. These results indicate that microbial metabolism exhibited a dominant role in DOM generation. As DOM concentration declined, increased soil oxygen availability regulated DOM composition and enhanced its biodegradability mainly through mediating microbial metabolism and Fe oxidation. The oxygen-induced oxidation of Fe(II) to Fe(III) removed complex DOM compounds with large molecular weight. Moreover, increased oxygen availability stimulated oxidase-catalyzed depolymerization of aromatic substances, and promoted production of protein-like DOM components due to lower enzymatic C/N acquisition ratio. As global changes in temperature and moisture will have large impacts on soil oxygen availability, the role of oxygen in regulating DOM dynamics highlights the importance of integrating soil oxygen supply with microbial metabolism and Fe redox status to improve model predictions of soil carbon under climate change.

A label-free fluorescent biosensor for amplified detection of T4 polynucleotide kinase activity based on rolling circle amplification and catalytic hairpin assembly

T4 polynucleotide kinase (PNK) plays a key role in maintaining genome integrity and repairing DNA damage. In this paper, we proposed a label-free fluorescent biosensor for amplified detection of T4 PNK activity based on rolling circle amplification (RCA) and catalytic hairpin assembly (CHA). Firstly, we designed a padlock probe with a 5′-hydroxyl terminus for phosphorylation reaction, a complementary sequence of the primer for initiating RCA, and a complementary sequence of the trigger for triggering CHA. T4 PNK catalyzed the phosphorylation reaction by adding a phosphate group to the 5′-hydroxyl terminus of padlock probe, generating a phosphorylated padlock probe. Then it hybridized with the primer to generate a circular probe under the action of ligase. Subsequently, the primer initiated an RCA reaction along the circular probe to synthesize a large molecular weight product with repetitive trigger sequences. The triggers then triggered the cyclic assembly reactions between hairpin probe 1 and hairpin probe 2 to generate a large amount of complexes with free G-rich sequences. The free G-rich sequences folded into G-quadruplex structures, and the N-methylmesoporphyrin IXs were inserted into them to produce an amplified fluorescent signal. Benefiting from high amplification efficiency of RCA and CHA, this fluorescent biosensor could detect T4 PNK as low as 6.63 × 10−4 U mL−1, and was successfully applied to detect its activity in HeLa cell lysates. Moreover, this fluorescent biosensor could effectively distinguish T4 PNK from other alternatives and evaluate the inhibitory effect of inhibitor, indicating that it had great potential in drug screening and disease treatment.

Integration of LC/MS-based molecular networking and molecular docking allows in-depth annotation and prediction of the metabolome: A study of Salvia miltiorrhiza Bunge

Plant secondary metabolites play essential roles in plant-environment interactions and biological communication. Although untargeted metabolomics is widely used in plant research, it suffers from limited annotated metabolites and relatively poor reliability. Herein, we report a technical route of untargeted metabolomics that involves using MS-DAIL to preprocess the data, using Cytoscape to construct a molecular network and quickly expand secondary metabolites annotation, using SIRIUS4 to construct a mass spectrum tree and summarize the fragmentation rules, and using bioinformatics analysis and molecular docking to predict the latent effect of new compounds. The new method annotates metabolites and finds new substances according to mass spectrometry similarity, and predicts its potential application value before separating new substances. 34 tanshinones and 31 phenolic acids were rapidly annotated by the technical route, and the structures of two new salvianolic acids with large molecular weights were deduced by the summarized mass spectrometry fragmentation rules. The results of molecular docking indicated that the two new substances may act on aldose reductase and plasminogen . The new technical route established in this study is helpful for the identification of plant secondary metabolites and the prediction of potential application value of new compounds. The method established in this study is helpful to promote plant metabolomics studies. • A new technical route for rapid compound annotation is proposed. • The method identified two new phenolic acid compounds in Salvia miltiorrhiza. • Molecular docking methods are used to predict the potential activity of novel compounds.

The effect of substrate consumption on the increasing of biofloculans productivity and activity of cultivation by Alcaligenes latus

The efficient technology cultivation is developed as a respond to the emergence of clean technology trend issue to produce biogically degraded product. This research aims to review the effect of sweet potato hydrolysis concentration on biofloculan cultivation productivity and its effect on flocculation activity. Cultivation starts from cell refreshment to propagation and inoculation into cultivation medium which has been sterilized. Enzymatically, the sweet potato starch hydrolyzate supernatant usage (S) as a cultivation medium is expected can substitute glucose (G) synthetic medium and able to increase bioflocculant activity and bioabsorbent formation, while the Nitrogen substrate usage from CSL (C) and yeast extract (Y) into the medium. Cultivation of Alcaligenes latus can stimulate the formation of acid biopolymers which have large molecular weights. Furthermore, made a notation like SC-10 which is a medium of glucose supernatant factor with Corn steep liquor (CSL) with an initial sugar concentration level of 10 g/l. Control process including the analysis of reduced sugar (RS) and nitrogen, viscosity, pH, measurement of dry cell weight (DC), and flocculation activity (AF) is conducted during cultivation. The research results indicates the usage of sweet potato supernatan hydrolysate is to subsitute the synthetic mediums due to its ability to increase biofloculan activity. The best medium for biofloculan cultivation is SC-10 with kinetic parameter μ, 0,0834 hours-1; Xmax,12,54 g/l; m, 0,641 and n, 0,0105 g product/g biomass/hours; α, 0,409 and β, 0,0006 g biomass/g substrate/ hours; Yp/s, 68%; Yx/s, 97%. There is no significant viscosity changes during cultivation so that it can not be used as a production index. Flocculation Activity resulting from the cultivation of SC-10 medium is the strongest process in forming flok-flok while SC-30 medium is the least.

Transformation of dissolved organic matter in landfill leachate during a membrane bioreactor treatment

In this study, a cutting-edge mass spectrometry (MS) technique, Orbitrap fusion MS with ultrahigh resolution, was used to analyze the molecular composition, chemical properties, formation mechanism, and environmental impact of refractory dissolved organic matter (rDOM) in leachate. The results showed that the bioavailable DOM (bDOM) and rDOM constituents varied substantially during the biological treatment of landfill leachate. Compared with bDOM, the rDOM in leachate had a higher degree of unsaturation, aromaticity, and oxidation, and a larger molecular weight, and contained more organic matter with benzene ring and biphenyl structures. Using high-throughput 16S rRNA sequencing, metagenomics, the Kendrick mass defect (KMD), and a mass difference network (MDiN), it was found that rDOM in leachate is generated through carboxylation (+COO), dehydro-oligomerization (-H2), and chain scission (-CH2) pathways due to the activity of microbes such as Patescibacteria, Chloroflexi, and Proteobacteria. Compared with Suwannee River fulvic acid (SRFA), the rDOM in leachate contained more organics with nitrogen, sulfur, benzene rings, and biphenyls. If the rDOM in leachate enters the environment it will affect the composition of the original organic matter, and its biogeochemical transformation and environmental fate will then need to be monitored and may require special attention.

Metallic Porphyrazine Networks: Synthesis, as Well as Thermal and Optical Properties for Accelerating the Oxidation of Thiols to Their Disulfides

A condensation reaction of 2,3,5,6-tetraamino-1,4-benzoquinone 1 with 4,5-Dichloro-3,6-dihydroxy-phthalonitrile 2 produced p-benzoquinone [2,3-b:2,3-b]bis[(5,8-dihydroxybenzopyrazine)-6,7-dinitrile] 3. Utilizing acetic acid with lithium/pentanol, the tetra-nitrile monomer was cyclo-tetramerized, yielding the matching network polymer, tetra p-benzoquinone[2,3-b:2,3-b]. bis[(5,8-dihydroxybenzopyrazino) porphyrazine (2H-Pz) 4a. The equivalent tetra p-benzoquinone[2,3-b:2,3-b]bis[(5,8-dihydroxybenzopyrazino) metallic porphyrazine networks (M-Pz) M = Zn 4b or Ni 4c, were obtained by cyclo-tetramerizing the tetra-nitril monomer 3 using metal salt and quinoline. The synthesized molecules’ elemental analytical results, as well as their IR and NMR spectral data, are consistent with their assigned structures. The prepared compounds have large molecular weights and metal content, indicating that reactions of tetramerization, polymerization, and chelation were all productive. The synthesized porphyrazines were proved to be excellent substrates for oxidizing thiophenol and benzyl thiol to their respective disulfides in atmospheric oxygen. The maximal production of the corresponding disulfides after 15 min was 96 percent for thiophenol and 93 percent for benzyl thiol, respectively.

Non-invasive, targeted, and non-viral ultrasound-mediated brain-derived neurotrophic factor plasmid delivery for treatment of autism in a rat model.

Autism has clinical manifestations such as social interaction disorder, speech and intellectual development disorder, narrow interest range, and stereotyped and repetitive behavior, all of which bring considerable economic and mental burden to society and families, and represent a public health problem requiring urgent attention. Brain-derived neurotrophic factor (BDNF) plays an important role in supporting survival, differentiation, growth, and synapse formation of neurons and participates in the plasticity of nerves. However, it is difficult for BDNF to penetrate the blood-brain barrier (BBB) due to its large molecular weight. Low-frequency focused ultrasound (FUS) combined with microbubbles (MBs) has been demonstrated to be a promising method for opening the BBB non-invasively, transiently, and locally. Here, we studied the therapeutic effect of FUS combined with BDNF plasmid-loaded cationic microbubbles (BDNFp-CMBs) in a rat model of autism. BDNF-CMBs were prepared and the transfection efficiency of FUS combined with BDNF-CMBs was tested in vitro. A rat model of autism was established from the juvenile male offspring of Sprague-Dawley (SD) pregnant rats treated with sodium valproate (VPA) solution through intraperitoneal injection. The autism rats were randomized into three groups: the VPA group, which received no treatment, the BDNFp group, which was treated by injection of BDNFp, and the FUS + BDNFp-CMBs group, which was administered FUS combined with BDNFp-CMBs. Age-matched normal rats served as the control group (Con). Following treatment, stereotyped, exploratory, and social–behavioral tests were performed on the animals in each group. The rat brains were then collected for subsequent histological examination, and the changes in synaptic structures in the prefrontal cortex (PFC) were detected under transmission electron microscopy. The results showed that the constructed BDNFp could be loaded onto CMBs with high loading efficiency. The BDNFp-CMBs prepared in this study showed good stability in vivo. FUS combined BDNFp-CMBs could effectively and non-invasively open the BBB of rats. The stereotyped, exploratory, and social behaviors of the FUS + BDNFp-CMBs group were significantly improved. Compared to the VPA group, the abnormality of neuronal morphology and number in the PFC of the FUS + BDNFp-CMBs was alleviated to a certain extent and was accompanied by restoration of the damaged synapses in the encephalic region. Our work demonstrates the positive therapeutic effect of BDNF delivered by FUS non-invasively across the BBB into the PFC in a rat model of autism, offering a potential strategy for treating autism.

Electrochemical treatment for leachate membrane retentate: Performance comparison of electrochemical oxidation and electro-coagulation technology.

With the widespread use of membrane in advanced treatment of leachate, China produces a large amount of leachate membrane retentate (LMR) (≈23.4 million tons) annually, which is usually treated by incineration or recirculation in engineering, but these technologies have many drawbacks. LMR is suitable for electrochemical treatment due to its high electrical conductivity. This study compared the performances of electrochemical oxidation (EO) and electro-coagulation (EC) technology on LMR treatment under different experimental conditions, including anode material, current density, initial pH and reaction time. We found that EO optimal conditions achieved 70.1%, 83.1%, 78.7%, 98.7%, and 69.7% removal of total organic carbon (TOC), UV absorption (at 254nm), chromaticity, ammonia nitrogen (NH3-N), and total nitrogen (TN), respectively. Compared with EO, EC exhibited a similar removal ability for orgainics and better removals of chroma, but much less performance for removing nitrogen pollutants in the same reaction time, that is, removals of NH3-N and TN were only 31.5% and 36.2%, respectively. Meanwhile, EC showed much higher instantaneous current efficiency of COD than EO under its optimal reaction time (120min). In addition, the UV-Vis spectra and 3D fluorescence spectra indicated that EO exhibited relatively outstanding performance in decomposing dissolved organic matter (DOM) with rather complicated structures than EC. Also, the flow field-flow fractionation technique demonstrated that EO preferentially destroy humic-like, large molecular weight DOM, and converting them to smaller molecules, which resulted in more volatile organic compounds in EO samples than EC samples. While EC had little selectivity in the removal of organics, except humic-like DOM with relative small molecular. These findings can provide a theoretical basis for the electrochemical treatment of LMR.

Study of Properties of Local Polypropylene Compared to International Standard Properties

This study was conducted in the Khartoum refinery in Algylee to study the properties of polypropylene (grade 113 &amp;114) which are produced by the addition technique; they used refined propylene from Liquefied Petroleum Gas and Ziegler-Natta catalyst. The samples were taken from samples which are produced in (1-15)/08/2010 in three features (powder, granulates, and specimens). Both grades are homopolymer and isotactic polypropylene. They checked the component of liquefied petroleum gas by using a gas chromatography instrument and determination of thermal, mechanical, and physical properties. From the result, both grades differed in their properties according to molecular weight. Grade 113 has a large molecular weight which is suitable for the extrusion process while grade 114 has a small molecular weight which is suitable for the injection molding process. Each grade of polypropylene is within the standard range but they contain a slight amount (˂0.5ppm) of sulfur and moisture (49.1ppm) which are affecting product quality. However, if there is no separation unit the product will become yellowish and toxic.

Performance and mechanisms of enhanced hydrolysis acidification by adding different iron scraps: Microbial characteristics and fate of iron scraps.

HA, as one of low-carbon pre-treatment technology could be enhanced by packing of iron or iron oxide powder for enhancing the transformation of large molecular weight to generate volatile fatty acids (VFAs) for fuel production. However, the controversy of iron strengthening the HA and inherent drawbacks of iron oxide, such as poor mass transfer, and difficult recovery, limit this pretreatment technology. Clean and rusty iron scraps were packed into an HA system to address these issues while focusing on the system performance and the response of core bacterial and fungal microbiomes to iron scrap exposure. Results showed that clean and rusty iron scraps can significantly improve the HA performance while considering hydrolysis efficiency (HE), acidification efficiency (AE) and VFAs production, given that VFAs ratios (Cacetate: Cpropionate: Cbutyrate) were changed from the 14:5:1 to 14:2:1 and 29:4:1, respectively, and the obtained VFAs ratios in iron scraps addition systems were more closely to the optimal VFAs ratio for lipids production. Redundant and molecular ecological network analyses indicated that iron scraps promote the system stability and acidogenesis capacity by boosting the complexity of microbes’ networks and enriching core functional microbes that show a positive response to HA performance, among which the relative abundance of related bacterial genera was promoted by 19.71 and 17.25% for RRusty and RClean systems. Moreover, except for the differences between the control and iron scraps addition systems, the findings confirmed that the RRusty system is slightly different from the RClean one, which was perhaps driven by the behavior of 6.20% of DIRB in RRusty system and only 1.16% of homoacetogens in RClean system when considering the microbial community and fate of iron scraps. Totally, the observed results highlight the application potential of the iron scrap-coupled HA process for the generation of VFAs and provide new insights into the response of different iron scraps in microbes communities.

Establishment of a human cell line with a surface display system for screening and optimizing Na+-taurocholate cotransporting polypeptide-binding peptides.

One of the most desirable targets for HBV medications is the sodium taurocholate cotransporting polypeptide (NTCP), an entry receptor for the hepatitis B virus (HBV). N-myristoylated preS1 2–48 (Myrcludex B or Hepcludex), an NTCP-binding peptide from the large surface protein of HBV, has been developed as the first-in-class entry inhibitor. However, its relatively large molecular weight contributes to increased immunogenicity and antibody production. As a result, it is preferable to look for an NTCP-binding peptide with a smaller size. To do this, we developed a human cell surface display strategy and screened peptides based on preS1-21. PreS1-21 (genotype D) was extended by 7 random amino acids and fused with mCherry and FasL transmembrane domain. The pooled constructs were transfected into HEK293 cells by using the transposon/transposase system to create a library displaying various peptides on the cell surface with red fluorescence. On the other hand, we expressed NTCP protein fused with EGFP on HEK293 and used the membrane lysate containing NTCP-GFP as the bait protein to select peptides with increased NTCP affinity. After 7 cycles of selection, the deep sequencing results revealed that some polypeptides were more than 1,000 times enriched. Further screening of the mostly enriched 10 peptides yields the peptide preS1-21-pep3. Replacing the preS1-21 sequence of preS1-21-pep3 with those from different genotypes demonstrated that the consensus sequence of genotype A–F had the best performance. The peptide (Myr-preS1-21-pep3) was synthesized and tested on the HepG2-NTCP cell model. The results showed that Myr-preS1-21-pep3 is approximately 10 times more potent than the initial peptide Myr-preS1-21 in preventing HBV infection. In conclusion, we developed a new strategy for screening peptides binding to membrane proteins and identified a new NTCP-binding peptide with a much smaller size than Hepcludex.

In Vivo Degradation Studies of PGA-PLA Block Copolymer and Their Histochemical Analysis for Spinal-Fixing Application.

Polylactic acid (PLA) and polyglycolic acid (PGA) are well-known medical-implant materials. Under the consideration of the limitations of degradable polymeric materials, such as weak mechanical strength and by-product release through the biodegradation process under in vivo environments, PLA–PGA block copolymer is one of the effective alternative implant materials in the clinical field. In our previous study, two types of extremely effective PGA–PLA copolymers (multi/tri-block PGA–PLA copolymers) were synthesized. These synthesized block copolymers could overcome aforementioned issues and also showed good biocompatibility. In this study, the PGA–PLA block copolymers with large molecular weight were synthesized under the same chemical scheme, and their bio durability was confirmed through the in vivo degradation behavior and histochemical analyses (by hematoxylin and eosin and immune staining) in comparison with commercial PLGA random copolymer (medical grade). Specimens for the degradation test were investigated by SEM and X-ray diffractometer (XRD). As a result, the synthesized PGA–PLA block copolymer showed good biocompatibility and had a controlled biodegrading rate, making it suitable for use in resorbable spinal-fixation materials.

Lignin molecular design to transform green manufacturing

<h2>Summary</h2> Lignin is the most abundant phenolic biopolymer on earth, representing an abundant feedstock for green manufacturing. Nevertheless, the diverse chemical linkages, heterogeneous functional groups, variable molecular weights, and amphiphilic structures all prevent the synthesis of fungible materials from lignin, leaving it as a predominantly low-value resource. On the basis of structure-property relationship, we synergistically overcome these challenges by chemical design of a type of lignin, high-molecular weight esterified linkage lignin (HiMWELL), with more uniform esterified linkages, larger molecular weight, and much lower OH group content via interunit substucture replacement. HiMWELL transforms lignin into a precursor for manufacturing renewable materials with drastically improved properties and functionality. The HiMWELL-based carbon fiber achieved a record tensile strength and better mechanical properties than the control polyacrylonitrile carbon fiber. HiMWELL also uniquely improved mechanical properties of the recyclable polymer blends and achieved UV-shading effects.