High Molecular Weight Research Articles

Optimization and Techno-Economic analysis of catalytic gasification of wheat straw biomass using ASPEN PLUS model

Biomass gasification efficiently produces heat, electricity, and power. However, removing harmful contaminants from raw syngas is crucial. Tar production is a challenge due to blockage, plugging, and corrosion. Tar steam reforming (TSR) is the most promising technique, converting high molecular weight hydrocarbons into CO, CO2, H2, and CH4. In this study, a model of biomass gasification using wheat straw as biomass feedstock has been developed using Aspen Plus. The gasification flow sheet encompasses gasification, catalytic filter candle, gas cleaning, impurity removal reactor, separator, and subsequent sorbent reactors. Ni-based catalysts with Ni ratios (5%, 10%, and 15%) are used to simulate TSR reactions. Results show that the 15% Ni-Co-Al2O3 catalyst outperforms the 10% and 5% Ni-Co-Al2O3 catalysts. This study explores the impact of temperature, catalyst loadings, and steam-to-carbon (S/C) ratios on toluene conversion and hydrogen yield in catalytic steam reforming, along with temperature, steam-to-biomass ratios, and equivalence ratio on syngas fraction in gasification. It includes a techno-economic analysis of wheat straw gasification to improve syngas energy through efficient tar conversion.

Biodistribution of Native and Nanoformulated Innate Defense Regulator Peptide 1002.

Innate defense regulator-1002 (IDR-1002) is a synthetic peptide with promising immunomodulatory and antibiofilm properties. An appreciable body of work exists around its mechanism of action at the cellular and molecular level, along with its efficacy across several infection and inflammation models. However, little is known about its absorption, distribution, and excretion in live organisms. Here, we performed a comprehensive biodistribution assessment with a gallium-67 radiolabeled derivative of IDR-1002 using nuclear tracing techniques. Various dose levels of the radiotracer (2-40 mg/kg) were administered into the blood, peritoneal cavity, and subcutaneous tissue, or instilled into the lungs. The peptide was well tolerated at all subcutaneous and intraperitoneal doses, although higher levels were associated with delayed absorption kinetics and precipitation of the peptide within the tissues. Low intratracheal doses were rapidly absorbed systemically, and small increases in the dose level were lethal. Intravenous doses were rapidly cleared from the blood at lower levels, and upon escalation, were toxic with a high proportion of the dose accumulating within the lung tissue. To improve biocompatibility and prolong its circulation within the blood, IDR-1002 was further formulated onto high molecular weight hyperbranched polyglycerol (HPG) polymers. Constructs prepared at 5:1 and 10:1 peptide-to-polymer ratios were colloidally stable, maintained the biological profile of the peptide payload and helped reduce red blood cell lysis. The 5:1 construct circulated well in the blood, but higher peptide loading was associated with rapid clearance by the reticuloendothelial system. Many peptides face pharmacokinetic and biocompatibility challenges, but formulations such as those with HPG have the potential to overcome these limitations.

Structure, spectral properties and antioxidant activity of melanoidins extracted from high temperature sterilized lotus rhizome juice

Melanoidins are complex macromolecular compounds closely associated with the browning phenomenon in high-temperature sterilized lotus rhizome juice (HTSL). This study aimed to preliminarily investigate the structural properties of melanoidins extracted from HTSL. Results showed that the average molecular weight of HTSL melanoidins ranged from 1.48 to 41.40 kDa. Medium and high molecular weight melanoidins were the main contributors to the brown color of HTSL. Sugars, proteins, and phenolics were present in HTSL, among which sugar was the most abundant, with glucose being the predominant monosaccharide in acid degradation products of melanoidins. Through fluorescence and ultraviolet spectral analysis, we found that the melanoidins contained carboxyl and carbonyl compounds, as well as furan and pyran heterocyclic compounds. The infrared spectra and nuclear magnetic resonance spectra revealed a prominent sugar absorption peak, indicating that sugar was the main component of the melanoidins of HTSL. Furthermore, in vitro antioxidant experiments showed that the antioxidant activity of melanoidins was significantly positively correlated with phenolic compounds. Our results indicated that there were differences in the structural properties of melanoidins fractions with different molecular weights. MW-H fraction significantly impacted the color and antioxidant activity of HTSL.

Fine-tuning an aromatic ring-hydroxylating oxygenase to degrade high molecular weight polycyclic aromatic hydrocarbon

Rieske nonheme iron aromatic ring-hydroxylating oxygenases (RHOs) play pivotal roles in determining the substrate preferences of polycyclic aromatic hydrocarbon (PAH) degraders. However, their potential to degrade high molecular weight PAHs (HMW-PAHs) has been relatively unexplored. NarA2B2 is an RHO derived from a thermophilic Hydrogenibacillus sp. strain N12. In this study, we have identified four “hotspot” residues (V236, Y300, W316, and L375) that may hinder the catalytic capacity of NarA2B2 when it comes to HMW-PAHs. By employing structure-guided rational enzyme engineering, we successfully modified NarA2B2, resulting in NarA2B2 variants capable of catalyzing the degradation of six different types of HMW-PAHs, including pyrene, fluoranthene, chrysene, benzo[a]anthracene, benzo[b]fluoranthene, and benzo[a]pyrene. Three representative variants, NarA2B2W316I, NarA2B2Y300F-W316I, and NarA2B2V236A-W316I-L375F, not only maintain their abilities to degrade low molecular weight PAHs (LMW-PAHs), but also exhibited 2-4 times higher degradation efficiency for HMW-PAHs in comparison to another isozyme, NarAaAb. Computational analysis of the NarA2B2 variants predict that these modifications altering the size and hydrophobicity of the active site pocket making it more suitable for HMW-PAHs. These findings provide a comprehensive understanding of the relationship between three-dimensional structure and functionality, thereby opening up possibilities for designing improved RHOs that can be more effectively used in the bioremediation of PAHs.

Transglutaminase-mediated stiffening of the glomerular basement membrane mitigates pressure-induced reductions in molecular sieving coefficient by reducing compression

Proteinuria, the presence of high molecular weight proteins in the urine, is a primary indicator of chronic kidney disease. Proteinuria results from increased molecular permeability of the glomerular filtration barrier combined with saturation or defects in tubular protein reabsorption. Any solute that passes into the glomerular filtrate traverses the glomerular endothelium, the glomerular basement membrane, and the podocyte slit diaphragm. Damage to any layer from the filter has reciprocal effects on other layers to increase glomerular permeability. The GBM is thought to act as a compressible ultrafilter that has increased molecular selectivity with increased pressure due to compression that reduced the porosity of the GBM with increased pressure. In multiple forms of chronic kidney disease, crosslinking enzymes are upregulated and may act to increase GBM stiffness. Here we show that enzymatically crosslinking porcine GBM with transglutaminase increases the stiffness of the GBM and mitigates pressure-dependent reductions in molecular sieving coefficient. This was modeled mathematically using a modified membrane transport model accounting for GBM compression. Changes in the mechanical properties of the GBM may contribute to proteinuria through pressure-dependent effects on GBM porosity.

Analytical data of Acacia nilotica var. Nilotica gum

This study aimed to characterize the exudate gum from Acacia nilotica var. nilotica in Sudan and compare its physicochemical properties to Acacia seyal var. seyal and Acacia senegal var. senegal (gum Arabic). Samples were collected from six different states in Sudan over three seasons. The gum had a moisture content of 10.50%, ash content of 1.86%, pH value of 5.19, specific optical rotation of +94.70, intrinsic viscosity of 10.44 cm3 g-1, nitrogen content of 0.024%, protein content of 0.16%, acid equivalent weight of 1907.82, and total uronic acid content of 10.18%. Sugar content analysis revealed arabinose (41.20%), galactose (17.43%), and rhamnose (10.68%). Potassium was the predominant cation, followed by calcium, magnesium, sodium, lead, and iron. Acacia nilotica was classified as part of the Gummeferae series and exhibited a positive specific optical rotation. The Number average molecular weight (Mn) was estimated using osmometric measurements and gel permeation chromatography. The gum had a higher molecular weight and lower intrinsic viscosity compared to gum Arabic, suggesting a spheroidal shape of molecule. Amino acid analysis showed similarities with gum Arabic, with hydroxyproline and serine as principal amino acids. Variations in cationic composition were attributed to differences in soil type among collection locations. KEY WORDS: Physicochemical characterization, Acacia senegal var. senegal gum, Acacia seyal var. seyal gum, Acacia nilotica var. nilotica gum, gammiferae Bull. Chem. Soc. Ethiop. 2024, 38(4), 839-852. DOI: https://dx.doi.org/10.4314/bcse.v38i4.2

Discovery of a New Anti-Inflammatory Agent from Anemoside B4 Derivatives and Its Therapeutic Effect on Colitis by Targeting Pyruvate Carboxylase.

Anemoside B4 (AB4), a triterpenoidal saponin from Pulsatilla chinensis, shows significant anti-inflammatory activity, and may be used for treating inflammatory bowel disease (IBD). Nevertheless, its application is limited due to its high molecular weight and pronounced water solubility. To discover new effective agents for treating IBD, we synthesized 28 AB4 derivatives and evaluated their cytotoxic and anti-inflammatory activities in vitro. Among them, A3-6 exhibited significantly superior anti-inflammatory activity compared to AB4. It showed a significant improvement in the symptoms of DSS-induced colitis in mice, with a notably lower oral effective dose compared to AB4. Furthermore, we discovered that A3-6 bound with pyruvate carboxylase (PC), then inhibited PC activity, reprogramming macrophage function, and alleviated colitis. These findings indicate that A3-6 is a promising therapeutic candidate for colitis, and PC may be a potential new target for treating colitis.

Thorough Validation of Optimized Size Exclusion Chromatography-Total Organic Carbon Analysis for Natural Organic Matter in Fresh Waters.

Size exclusion chromatography with total organic carbon detection (HPSEC-TOC) is a widely employed technique for characterizing aquatic natural organic matter (NOM) into high, medium, and low molecular weight fractions. This study validates the suitability of HPSEC-TOC for a simplified yet efficient routine analysis of freshwater and its application within drinking water treatment plants. The investigation highlights key procedural considerations for optimal results and shows the importance of sample preservation by refrigeration with a maximum storage duration of two weeks. Prior to analysis, the removal of inorganic carbon is essential, which is achieved without altering the NOM composition through sample acidification to pH 6 and subsequent N2-purging. The chromatographic separation employs a preparative TSK HW-50S column to achieve a limit of detection of 19.0 µgC dm-3 with an injection volume of 1350 mm-3. The method demonstrates linearity up to 10,000 µgC dm-3. Precision, trueness and recovery assessments are conducted using certified reference materials, model compounds, and real water samples. The relative measurement uncertainty in routine analysis ranges from 3.22% to 5.17%, while the measurement uncertainty on the bias is 8.73%. Overall, the HPSEC-TOC represents a reliable tool for NOM fractions analysis in both treated and untreated ground and surface water.

ASSESSMENT OF HIGH MOLECULAR WEIGHT PROTEINS IN SELECTED INDIGENOUS BREAD WHEAT VARIETIES OF PAKISTAN

Higher molecular weight gluten subunits (HMW-GS) articulate variation in allelic frequency, reflecting a strong correlation with bread quality. In order to determine this quality trait, 23 different Pakistani indigenous wheat varieties were screened that may be used as selection criteria in a breeding program. For detecting variations in HMW-GS, sodium dodecyl sulfate acrylamide gel electrophoresis was used. In all, 77 Glu-1 were identified including 25 at Glu-A1, 26 at Glu-B1 and 26 at Glu-D1. Alleles at Glu-1 were 2* with a frequency of 53.3% and N with 60% frequency at Glu-A1, 6+8 with 60%, 17+18 with 45 % at Glu-B1 and 5+10 with 60% and 72% at Glu-D1. The highest frequency of subunits 20 and 5+10 were found at Glu-B1-e and Glu-D1 (a), followed by a frequency of 2* and Null at Glu-A1 (b, c), which is then followed by 2+12 at GluD-1 (a). The lowest frequency of 13+16, 17+18 and 6+8 were observed at Glu-B1 (f, i, d), respectively. Glu-A1, Glu-B1, and Glu-D1 alleles showed genetic index (i.e. 0.587, 0.54), (0.587. 0.065 and 0.48, 0.39, respectively) with an average of 0.55 and 0.37. The glu-D1 locus has a lower genetic index comparatively. The composition N, 20, 5+10 was found in maximum number (4) in Fakhr-e-Sarhad, Pasban, Pirsabak-2004 and Tatara genotypes, followed by the composition of 2*, 20, 2+12 in one check (Marvi-2000) and two varieties i.e. Chakwal-97 and Bakhtawar-92. The results describing the allelic frequency and composition of bread wheat would benefit further breeding plans for wheat to select good quality parameters.

Review on microbial production of exopolysaccharides and its applications

Exopolysaccharides (EPS) are bio-molecules produced by variety of microorganisms by both eukaryotes and prokaryotic. EPS are high molecular weight molecules available in both homopolysaccharide and heteropolysaccharide. Plants are the primary source of exopolysaccharides (EPS); however, microbiological EPS have a diverse range of structures and functions that enable them to endure harsh environmental conditions. Studying the structure and composition of exopolysaccharides is crucial for understanding their beneficial functions and potential applications in different fields such as food, dairy, medical, pharmaceutical, cosmetics and other industries. This review briefly describes how extremities trigger microbes to produce EPS with unique properties. In addition, it covers optimization and strain improvement methods to increase the productivity of microbes, extraction and purification methods. Similarities and differences of solid-state fermentation and submerged fermentation for EPS production from Bacteria and Fungi are sighted in this review. Applications of EPS in different fields owing to their various physicochemical properties are also discussed in this review. This review provides explanations with respect to microbial habitats, fermentation scales, purification methods and recent research on their potential applications.

Effect of Lactiplantibacillus plantarum CNPC003 and milk pasteurization on artisanal goat coalho cheese characteristics

This study evaluated the effect of adding Lactiplantibacillus plantarum CNPC003 (LP) and applying milk pasteurization on the microbiological, technological, and physicochemical characteristics and protein profile of artisanal goat coalho cheese during 60 days of ripening. Four types of cheese were produced, including cheeses made with raw and pasteurized goat milk and with and without LP (RC, PC, RCLP, and PCLP). All cheeses were safe for consumption and maintained high lactic acid bacteria counts (above 8 log CFU mL−1) at the end of the ripening period. RC and RCLP showed higher hardness and lower chewiness than cheeses made with pasteurized milk (PC and PCLP) after 60 days of ripening. As expected, there was a reduction in lactose content with a simultaneous increase in acidity and syneresis for all cheeses over the 60 days of ripening, with no significant change in the other evaluated physicochemical parameters. Proteolysis rates increased in all cheeses up to 60 days of ripening, aligning with elevated levels of soluble protein and free amino acids. After 60 days of ripening, PC showed a higher extent of proteolysis index, higher amount of high molecular weight peptides, higher number of identified proteins, and lower content of free amino acids. RCLP showed a higher depth of proteolysis index, higher free amino acids amount (1583 ± 3.95 mg 100 g−1), and fewer identified proteins. Among the peptides identified, it was possible to define 30 potential bioactive peptides according to the bioactivity score (>0.5), where both cheeses added with LP had 18 of these peptides, mostly potentially ACE inhibition sequences. The addition of LP and the pasteurization of milk positively affected the microbiological safety of ripened coalho goat cheeses, primarily contributing to the differentiation of their texture and protein and bioactivity profile.

Sliding mass floor system for seismic response control

A new concept of small sliding mass blocks as distributed bi-directional friction tuned mass dampers (TMD) is developed and tested for seismic response control of a framed building model. The proposed distributed TMD system can be accommodated within a depth of 10 cm at each floor of the building and does not require any specialized tools and is suitable for enhancing seismic performance of existing buildings as well. An analytical model has been developed for the modelling of distributed friction TMDs and the model has been validated by comparing predicted response with the experimental observations during a shake table test for a steel portal frame with distributed friction TMDs. It is found that the proposed distributed friction TMDs can reduce the seismic response by as much as 60% for mass ratio of 8% and tuning ratio of 0.9 with respect to the first normal mode of the building. A parametric study using different earthquake ground motions suggests that the coefficient friction of 0.2 has the most robust performance. The interface between ultra high molecular weight polyethylene (UHMWPE) and steel provides the desired coefficient of friction. This pair of sliding interfaces is also desirable from the point of view of durability as UHMWPE is highly abrasion resistant and is widely used in orthopedic implants. The proposed arrangement of distributed friction TMDs readily allows for the possibility of each mass block to be used as bi-directional TMD and tuned to different mode of vibration, if required. These distributed TMDs are also found to be very effective in greatly reducing the storey drifts in buildings on hill slopes. The results suggest that it is possible to achieve the immediate occupancy performance objectives even during extreme (MCE) level events with the help of proposed distributed friction TMDs.

Enhanced Aerosol Source Identification by Utilizing High Molecular Weight Signals in Aerosol Mass Spectra

Enhanced Aerosol Source Identification by Utilizing High Molecular Weight Signals in Aerosol Mass Spectra

Bioavailability enhancement of coenzyme Q10: An update of novel approaches.

Coenzyme Q10 (CoQ10) is an essential, lipid-soluble vitamin involved in electron transport in the oxidoreductive reactions of the mitochondrial respiratory chain. Structurally, the quinone ring is connected to an isoprenoid moiety, which has a high molecular weight. Over the years, coenzyme Q10 has become relevant in the treatment of several diseases, like neurodegenerative disorders, coronary diseases, diabetes, hypercholesterolemia, cancer, and others. According to studies, CoQ10 supplementation might be beneficial in the treatment of CoQ10 deficiencies and disorders associated with oxidative stress. However, the water-insoluble nature of CoQ10 is a major hindrance to successful supplementation. So far, many advancements in CoQ10 bioavailability enhancement have been developed using novel drug carriers such as solid dispersion, liposomes, micelles, nanoparticles, nanoemulsions, self-emulsifying drug systems, or various innovative approaches (CoQ10 complexation with proteins). This article aims to provide an update on methods to improve CoQ10 solubility and bioavailability.

Polyaminated, acetylated and stop codon readthrough of recombinant Francisella tularensis universal stress protein in Escherichia coli.

Recombinant Francisella tularensis universal stress protein with a C-terminal histidine-tag (rUsp/His6) was expressed in Escherichia coli. Endogenous F. tularensis Usp has a predicted molecular mass of 30 kDa, but rUsp/His6 had an apparent molecular weight of 33 kDa based on Western blot analyses. To determine the source of the higher molecular weight for rUsp/His6, post translational modifications were examined. Tryptic peptides of purified rUsp/His6 were subjected to liquid chromatography tandem mass spectrometry (LC-MS/MS) and fragmentation spectra were searched for acetylated lysines and polyaminated glutamines. Of the 24 lysines in rUsp/His6, 10 were acetylated (K63, K68, K72, K129, K175, K201, K208, K212, K233, and K238) and three of the four glutamines had putrescine, spermidine and spermine adducts (Q55, Q60 and Q267). The level of post-translational modification was substoichiometric, eliminating the possibility that these modifications were the sole contributor to the 3 kDa extra mass of rUsp/His6. LC-MS/MS revealed that stop codon readthrough had occurred resulting in the unexpected addition of 20 extra amino acids at the C-terminus of rUsp/His6, after the histidine tag. Further, the finding of polyaminated glutamines in rUsp/His6 indicated that E. coli is capable of transglutaminase activity.

Characteristics of VE/HXLPE wear particle morphology: A comparative analysis with UHMWPE in an in vitro artificial tibial insert simulation test

Particle generation from artificial knee prostheses is a leading cause of artificial joint failures. Vitamin E stabilized highly cross-linked polyethylene (VE/HXLPE) is known for its antioxidant properties and minimal wear characteristics. However, research on the wear behavior of VE/HXLPE is limited. This study aims to compare wear debris from VE/HXLPE with the conventional material Ultra High Molecular Weight Polyethylene (UHMWPE) under identical in vitro test conditions. Specifically, Principal Component Analysis (PCA) was employed to morphologically categorize particles, resulting in four distinct groups for VE/HXLPE and five for UHMWPE. Notably, 68 % of VE/HXLPE particles exhibited small-sized spheroidal morphology, while UHMWPE mainly produced elongated bioactive particles. Key particle attributes were then assessed, including 'equivalent circle diameter (ECD)', 'aspect ratio (AR)', and 'roundness (R) ', and presented as frequency distributions. The morphological analysis revealed that VE/HXLPE particles displayed various shapes, such as spheroidal, flakes, bulks, rods, and fibrils, and their formation mechanism was discussed. Additionally, the Functional Biological Activity (FBA) of VE/HXLPE wear particles was calculated. The results demonstrated differences in particle sizes, shape distributions, and bioactivity between VE/HXLPE and UHMWPE, which indicates that VE/HXLPE particles had a lower likelihood of inducing osteolysis. This study holds promise for gaining deeper insights into the mechanical properties and the potential for bioactivity in VE/HXLPE as an artificial joint material.

Oxygen-initiated radical ring-opening polymerization of macrocyclic allylic sulfides under ambient conditions

Although radical ring-opening polymerization (ROP) is a powerful approach for synthesizing polymers with diverse backbone structures, the intrinsic oxygen sensitivity of radicals challenges the ability to perform these polymerizations under air conditions. Here, we reported a novel oxygen-initiated radical ROP of macrocyclic allylic sulfides that can efficiently proceed under an air atmosphere, enabling the construction of sulfur-containing polymers with moderate to high molecular weights. The versatility of this approach was further demonstrated by copolymerizing macrocyclic allylic sulfides with vinyl monomers to create degradable vinyl polymers under ambient conditions. Density functional theory calculations revealed that the quenching of radicals by oxygen in the chain-growth process was kinetically disfavored, thereby allowing the polymerization to be compatible with oxygen. This work will further advance applications of radical ROP in diverse fields by enhancing its tolerance towards oxygen.

Encapsulation of probiotic Lacticaseibacillus casei with whey protein isolate/soybean hull polysaccharide enhances cell viability in harsh conditions

Whey protein isolate (WPI)-soybean hull polysaccharide (SHP) Maillard reaction conjugates were used to encapsulate Lacticaseibacillus casei and determine the effect of encapsulation on bacterial viability during freeze drying, simulated pasteurization simulated gastrointestinal digestion and storage. The WPI-SHP conjugates were characterized by degree of conjugation, size-exclusion chromatography, infrared and fluorescence spectroscopy and other analyses. The degree of conjugation, the formation of Maillard reaction products and the content of high molecular weight conjugates increased with reaction time. The emulsification capacity and glass transition temperature (Tg) of the WPI-SHP conjugates peaked after 4 days of reaction, at a Tg of 140.51 ± 2.76 °C, an emulsification activity index of 9.12 m2/g and emulsion stability index of 87.01%. WPI-SHP4d had the best protection effect of probiotics under freeze drying, simulated pasteurization and gastrointestinal digestion. These findings provide valuable insights into the selection of encapsulating agents to improve probiotic viability in functional foods.

Improved Yield of SPRI Beads–Based Size Selection in the Very High Molecular Weight Range

Improved Yield of SPRI Beads–Based Size Selection in the Very High Molecular Weight Range

DNA Quantity and Quality Comparisons between Cryopreserved and FFPE Tumors from Matched Pan-Cancer Samples

Personalized cancer care requires molecular characterization of neoplasms. While the research community accepts frozen tissues as the gold standard analyte for molecular assays, the source of tissue for testing in clinical cancer care comes almost universally from formalin-fixed, paraffin-embedded tissue (FFPE). As newer technologies emerge for DNA characterization that requires higher molecular weight DNA, it was necessary to compare the quality of DNA in terms of DNA length between FFPE and cryopreserved samples. We hypothesized that cryopreserved samples would yield higher quantity and superior quality DNA compared to FFPE samples. We analyzed DNA metrics by performing a head-to-head comparison between FFPE and cryopreserved samples from 38 human tumors representing various cancer types. DNA quantity and purity were measured by UV spectrophotometry, and DNA from cryopreserved tissue demonstrated a 4.2-fold increase in DNA yield per mg of tissue (p-value < 0.001). DNA quality was measured on a fragment microelectrophoresis analyzer, and again, DNA from cryopreserved tissue demonstrated a 223% increase in the DNA quality number and a 9-fold increase in DNA fragments > 40,000 bp (p-value < 0.0001). DNA from the cryopreserved tissues was superior to the DNA from FFPE samples in terms of DNA yield and quality.