Variation Of Molecular Weight Research Articles

Modified acid polysaccharide derived from Salvia przewalskii with excellent wound healing and enhanced bioactivity

Acid polysaccharide was extracted from Salvia przewalskii root powders (PSP), purified by diethylaminoethyl cellulose column (DEAE-52) and molecular sieve (PSP2). PSPm1 was obtained by modifying PSP2 with nitrite and phosphoric acid. The chemical structure of PSP2 and PSPm1 exhibited notable distinctions, primarily due to the absence of arabinose and promotion of glucuronic acid (GlcA). The structure of PSPm1 was deduced through the utilization of 1H, 13C, and 2-D NMR. The main chain was linked by α-D-Galp(1 → 3)-α-Glcp-(1 → fragments and →6)-β-D-Galp fragments, with the presence of →4)-α-D-GlcpA-(1 → 6)-β-D-Galp-(1 → ， → 4)-α-D-GalAp-(1 → 2,4)-α-D-Rhap-(1 → fragments and →6)-α-Glcp-(1 → 2,4)-β-D-Manp-(1 → fragments. PSPm1 exhibited different immunoregulatory bioactivity in vitro, including haemostatic effects indicated by activated clotting time of 55.5 % reduction by the activated clotting time (ACT) test and wound healing function in vivo. PSPm1 also displayed better anti-tumor biological effects than unmodified. The structure-activity dissimilarity between PSP2 and PSPm1 primarily stems from variations in molecular weight (Mw), monosaccharide composition, and branching patterns. The modification of polysaccharides from the extract residues of Chinese medicinal materials may be a new form of drug supplements.

Effect of Poly(ethylene glycol)–Poly(propylene glycol) Triblock Copolymers on Autogenous Shrinkage and Properties of Cement Pastes

This study investigates the hydration, microstructure, autogenous shrinkage, electrical resistivity, and mechanical properties of Portland cement pastes modified with PEG-PPG triblock copolymers with varied molecular weights. The early age properties including setting time and hydration heat were examined using the Vicat test and isothermal calorimetry. The hydration products and pore size distribution were analyzed using thermogravimetric analysis (TGA) and nitrogen adsorption, respectively. Mechanical properties and electrical resistivity were evaluated using the compressive strength test and electrochemical impedance spectroscopy (EIS). It was shown that the addition of the copolymers reduced the surface tension of the cement paste pore solution due to the presence of a hydrophobic block (PPG) in the molecular structure of the copolymers. The setting time and hydration heat were relatively similar in the control paste as well as the pastes modified with the copolymers. The results showed that copolymers were able to reduce the autogenous shrinkage in the paste due primarily to a reduction in pore solution surface tension. TGA showed a slight increase in the hydration degree of the paste modified with the copolymers. The compressive strength was reduced in the pastes modified with the copolymers that showed an increased volume of air voids. The addition of copolymers did not affect the electrical resistivity of the pastes except in the case where there was a large volume of air voids, which acted as electrical insulators.

Polyhydroxyurethane and Poly(ethylene oxide) Multiblock Copolymer Networks: Crosslinking with Polysilsesquioxane, Reprocessing and Solid Polyelectrolyte Properties.

This contribution reports the synthesis of polyhydroxyurethane (PHU)-poly(ethylene oxide) (PEO) multiblock copolymer networks crosslinked with polysilsesquioxane (PSSQ). First, the linear PHU-PEO multiblock copolymers were synthesized via the step-growth polymerization of bis(6-membered cyclic carbonate) (B6CC) with α,ω-diamino-terminated PEOs with variable molecular weights. Thereafter, the PHU-PEO copolymers were allowed to react with 3-isocyanatopropyltriethoxysilane (IPTS) to afford the derivatives bearing triethoxysilane moieties, the hydrolysis and condensation of which afforded the PHU-PEO networks crosslinked with PSSQ. It was found that the PHU-PEO networks displayed excellent reprocessing properties in the presence of trifluoromethanesulfonate [Zn(OTf)2]. Compared to the PHU networks crosslinked via the reaction of difunctional cyclic carbonate with multifunctional amines, the organic-inorganic PHU networks displayed the decreased reprocessing temperature. The metathesis of silyl ether bonds is responsible for the improved reprocessing behavior. By adding lithium trifluoromethanesulfonate (LiOTf), the PHU-PEO networks were further transformed into the solid polymer electrolytes. It was found that the crystallization of PEO chains in the crosslinked networks was significantly suppressed. The solid polymer electrolytes had the ionic conductivity as high as 7.64 × 10-5 S × cm-1 at 300 K. More importantly, the solid polymer electrolytes were recyclable; the reprocessing did not affect the ionic conductivity.

Alzheimer’s Disease as a potential diabetes type III: Pilot Study of comorbidities related to AD

AbstractBackgroundAlzheimer’s disease (AD) is the most prevalent cause of dementia in the elderly population. It is a multifactorial disease in which metabolic dysregulation and glucose metabolism impairment plays a major role in the etiopathogenesis. In this research, we evaluate the comorbidities in a clinical trial for the novel biomarker Alz‐tau®, based on platelet tau, in cognitive healthy controls, mild‐cognitive impairment (MCI) and AD patients, in particular TII diabetes. Alterations in this biomarker appear to indicate high risk of developing AD, as demonstrated in previous clinical trials.MethodsFrom a cohort of 111 subjects, neuropsychology tests were performed to assign the respective group (control, MCI or AD). In addition, a health questionnaire to evaluate comorbidities. For the Alz‐tau® biomarker, platelets were obtained from plasma by centrifugation, lysed to obtain platelet protein extracts (containing tau) and further processed for a western blot analysis. The immuno‐ detection was performed with our novel monoclonal antibody tau51, which detects two variants of tau protein: a high molecular weight variant (HMW) and a low molecular weight variant (LMW). The results obtained were subjected to a densitometric analysis with ImageJ and the algorithm HWM/LMW was obtained.ResultFrom 111 patients, 17 presented diabetes type 2 as a comorbidity (15,3%). Out of them, 11 were cognitive healthy subjects (64.7%), 4 EA patients (23.5%) and 2 MCI (11.8%). Out of the control patients, 6 have the Alz‐tau® biomarker altered (54.5%), which was similar to what was observed in the EA patients (2 patients, 50%) and the MCI (1 patient, 50%). Of the 17 patients with diabetes, 53% presented an altered Alz‐tau® biomarker (cut‐off 1.2 algorithm), which is considered a risk factor for AD. It should be considered that the area under the curve (AUC) of this novel biomarker Alz‐tau® is 0.69, appropriate for a novel technique.ConclusionHere, we discovered that this early detection biomarker is correlated with the high‐risk factor of having AD in the future, since non‐symptomatic subjects exhibited an altered biomarker. Moreover, more than 50% of the TII diabetic positive cognitive healthy controls, exhibit an altered biomarker, sustaining our hypothesis of the correlation between glucose‐metabolism impairment, AD and oligomeric tau.

Intermediate Polymer Relaxation Explains the Anomalous Rheology of Nanocomposites with Ultrasmall Attractive POSS Nanoparticles.

The rheological properties of entangled polymers loaded with very small, strongly attractive polyhedral oligomeric silsesquioxane (POSS) fillers differ from that of nanocomposites with larger fillers by (1) the shorter breadth of the entanglement plateau and (2) the relatively unchanged terminal viscosity with increasing POSS loading. Although such anomalous rheological properties can rewrite the property-processing map of materials (e.g., high glass transition temperature and low viscosity), their mechanism remains unclear. In this study, we report that polymer relaxations on intermediate time scales between α and entire-chain relaxation, so-called "slower processes", are responsible for this unusual rheological behavior of poly(2-vinylpyridine)/octa(aminophenyl)silsesquioxane (P2VP/OAPS) nanocomposites. To uncover the effects of entanglements on the nanocomposite dynamics, rheometry is used for variable matrix molecular weights. Results show a systematic change in the rheological response, which is independent of the molecular weight, and in turn, the presence of entanglements. This supports a physical interpretation that a slower process dominates the rheological response of the material at intermediate frequencies on length scales larger than the segment length or the OAPS diameter, while the underlying physical time scales associated with the entanglement relaxation remain unchanged. Such insights are anticipated to assist the future rational design of other highly attractive and ultrasmall nanoparticles that enable a fine-tuned rheological response of nanocomposites across multiple length scales.

Toward well-defined colloidal particles: Efficient fractionation of lignin by a multi-solvent strategy

Colloidal lignin particles (CLPs) have sparked various intriguing insights toward bio-polymeric materials and triggered many lignin-featured innovative applications. Here, we report a multi-solvent sequential fractionation methodology integrating green solvents of acetone, 1-butanol, and ethanol to fractionate industrial lignin for CLPs fabrication. Through a rationally designed fractionation strategy, multigrade lignin fractions with variable hydroxyl group contents, molecular weights, and high purity were obtained without altering their original chemical structures. CLPs with well-defined morphology, narrow size distribution, excellent thermal stability, and long-term colloidal stability can be obtained by rational selection of lignin fractions. We further elucidated that trace elements (S, N) were reorganized onto the near-surface area of CLPs from lignin fractions during the formation process in the form of -SO42− and -NH2. This work provides a sustainable and efficient strategy for refining industrial lignin into high-quality fractions and an in-depth insight into the CLPs formation process, holding great promise for enriching the existing libraries of colloidal materials.

Experimental and theoretical study of PEG/natural clay-based hybrids properties: Role of molecular weight

The present study in this article is designed firstly for a physicochemical and mineralogical characterization of a clay mineral from the Meknes region. The natural clay was first crushed (agate mortar), sieved (63μm) and purified, then characterized to determine the different physicochemical parameters as well as the minerals it contains. Secondly, hybrids based on this natural clay and the polymer (Polyethylene glycol: PEG) were produced using the direct intercalation process. In our study, we were interested in elucidating the role of the PEG molecular weight variation on the final product. These composites were observed using different techniques at different scales for a multi-scale characterization of their microstructure. The obtained results indicate a homogeneous mineralogical composition characterized by the predominance of clay minerals (smectite, kaolinite, and illite) associated with other minerals such as quartz and calcite. Moreover, the measurements of the physico-chemical parameters show an average cation exchange capacity (29mequi/100g) and a specific surface of about 204m2/g. The transmission electron microscopy confirms the formation of the intercalated structures by insertion of PEG chains in good conformity with the X-ray diffraction (XRD) findings. Fourier transform infrared (FTIR) analysis reports the presence of new PEG-related vibrational bands in the hybrids, this confirms the adsorption of PEG chains. We find that there is a consensus that HPEG8000 hybrids are more suitable and stable and that 8000g/mol is the optimal molecular weight. Finally, the XRD results were used to follow the inter-layer distance of the phases versus the molecular weight of PEG. These results show a very good agreement with the theory developed by using the De Gennes scaling laws.

Engineering internal nanostructure in 3D‐printed materials via polymer molecular weight distribution

AbstractThe distribution of molecular weights in polymers, known as the molecular weight distribution (MWD), plays a significant role in dictating the behavior of polymer self‐assembly and influencing the characteristics of the resulting materials. This study investigates how MWD of macromolecular chain‐transfer agents (macroCTAs) impact internal nanostructures in materials prepared by polymerization‐induced microphase separation (PIMS) 3D printing. In the aim of elucidating this relationship, the study initially harnessed the precision offered by narrow‐MWD macroCTAs, which provide precise control over phase separation, as assessed by atomic force microscopy (AFM) and small‐angle X‐ray scattering (SAXS) measurements. Through systematic variation of macroCTA molecular weights, the dimensions of the distinct domains were precisely tuned from 10 to 90 nanometers and a decrease of materials stiffness was observed with increased domain size. In contrast, the utilization of a broader MWD, achieved by blending two distinct macroCTAs, resulted in increased domain size dispersity and reduced interface sharpness, without significantly affecting the mechanical properties of the 3D‐printed materials. Overall, this approach expands the strategies for manipulating the nanoscale architecture of 3D‐printed PIMS materials, opening new possibilities for printing advanced engineering materials with tailorable properties.

Structure and emulsifying properties of unprecedent glucomannan oligo- and polysaccharides from Amazonia Acrocomia aculeata palm fruit

Acrocomia aculeata fruit pulp contains oil (4.1–82.8 % fresh matter) and carbohydrates (6.6–98.0 % fresh matter). To date, only the oil fraction is valorized because very little is known about the nature of carbohydrates. This study explores new ways of adding value to this pulp by developing simple and efficient extraction processes for its carbohydrate components and characterizing their structure and physicochemical properties over two harvest periods. A water-soluble monosaccharide fraction F1 (solubility limit (SL): 98.5–99.3 g/L) (yield: 21 % dry pulp (DP)), a water-soluble polysaccharide fraction F2 (SL: 93.3–95.3 g/L) (yield: 26 % DP) and two additional water-insoluble polysaccharide fractions F3 and F4 (SL: <8 g/L) (yields: 10 and 19 % DP, respectively) were isolated. NMR structural characterizations of fraction F2 revealed it to be a linear glucomannan with β-(1 → 4) osidic linkages between d-Manp and d-Glcp residues. F2 is unique for its d-Manp/d-Glcp ratio of 3:1 and the position of its acetyl group (13–14 %, C-2 d-Manp). Finally, the polysaccharide showed a molecular weight (Mw) variation ranging from 8.2 × 104 to 1.1 × 103 Da over the two harvest periods, with remarkable emulsifying properties associated with a low Mw of F2 (stability >6 months, 1 % w/v in a water-in-oil emulsion).

Nitrosamine acceptable intakes should consider variation in molecular weight: The implication of stoichiometric DNA damage

N-nitrosamines (NAs) are a class of compounds of which many, especially of the small dialkyl type, are indirect acting DNA alkylating mutagens. Their presence in pharmaceuticals is subject to very strict acceptable daily intake (AI) limits, which are traditionally expressed on a mass basis. Here we demonstrate that AIs that are not experimentally derived for a specific compound, but via statistical extrapolation or read across to a suitable analog, should be expressed on a molar scale or corrected for the target substance's molecular weight. This would account for the mechanistic aspect that each nitroso group can, at maximum, account for a single DNA mutation and the number of molecules per mass unit is proportional to the molecular weight (MW). In this regard we have re-calculated the EMA 18 ng/day regulatory default AI for unknown nitrosamines on a molar scale and propose a revised default AI of 163 pmol/day. In addition, we provide MW-corrected AIs for those nitrosamine drug substance related impurities (NDSRIs) for which EMA has pre-assigned AIs by read-across. Regulatory acceptance of this fundamental scientific tenet would allow one to derive nitrosamine limits for NDSRIs that both meet the health-protection goals and are technically feasible.

Cellulose-Reinforced Polylactic Acid Composites for Three-Dimensional Printing Using Polyethylene Glycol as an Additive: A Comprehensive Review.

Growing concerns about environmental issues and global warming have garnered increased attention in recent decades. Consequently, the use of materials sourced from renewable and biodegradable origins, produced sustainably, has piqued the interest of scientific researchers. Biodegradable and naturally derived polymers, such as cellulose and polylactic acid (PLA), have consistently been the focus of scientific investigation. The objective is to develop novel materials that could potentially replace conventional petroleum-based polymers, offering specific properties tailored for diverse applications while upholding principles of sustainability and technology as well as economic viability. Against this backdrop, the aim of this review is to provide a comprehensive overview of recent advancements in research concerning the use of polylactic acid (PLA) and the incorporation of cellulose as a reinforcing agent within this polymeric matrix, alongside the application of 3D printing technology. Additionally, a pivotal additive in the combination of PLA and cellulose, polyethylene glycol (PEG), is explored. A systematic review of the existing literature related to the combination of these materials (PLA, cellulose, and PEG) and 3D printing was conducted using the Web of Science and Scopus databases. The outcomes of this search are presented through a comparative analysis of diverse studies, encompassing aspects such as the scale and cellulose amount added into the PLA matrix, modifications applied to cellulose surfaces, the incorporation of additives or compatibilizing agents, variations in molecular weight and in the quantity of PEG introduced into the PLA/cellulose (nano)composites, and the resulting impact of these variables on the properties of these materials.

Poly(propylene glycol)‐Based Non‐Isocyanate Polyurethane Ionenes: Thermal, Morphological and Conductive Properties

AbstractThe synthesis and characterization of a series of polyurethane ionenes using a non‐isocyanate approach is disclosed. Imidazole‐capped, urethane‐containing prepolymers are prepared by first reacting carbonyl diimidazole (CDI) with several poly(propylene glycol) (PPG) diols with variable molecular weight, followed by subsequent reaction with 3‐aminopropylimidazole (API). Polymerization with 1,4‐dibromomethylbenzene followed by anion exchange resulted in the desired polyurethane ionenes bearing the [NTf2] counteranion as a series of viscous liquids. NMR and FTIR spectroscopy are used to characterize the intermediates and final ionenes, including molecular weight determination by end‐group analysis. A single glass transition temperature (Tg), as determined by differential scanning calorimetry (DSC), is observed for each ionene (−38 to −64 °C) with the Tg decreasing with increasing PPG molecular weight. Thermogravimetric analysis (TGA) indicated a two‐step decomposition for each ionene, with the first being degradation of the PPG segment, followed by the urethane/ionic segment. Microphase separation is observed from x‐ray scattering profiles with Bragg distances that increased with increasing PPG molecular weight. Ionic conductivity is found to be inversely dependent upon DSC Tg at lower temperatures (RT and below); however, at higher temperatures, conductivity appears to be more dependent upon the ability of ionic aggregates caused by phase separation to interact.

Implications of Particle Size in the Extraction of Cellulose from the Calamagrostis Intermedia Species

This research aimed to elucidate the implications of particle size on cellulose extraction from the species Calamagrostis intermedia, endemic to Ecuador. Within the versatile cellulose extraction and trade industry, using timber sources results in a relentless environmental impact, mainly when no resource rationing occurs during the washing or bleaching phases. The investigation incorporated a sample pretreatment encompassing a drying, grinding, and sieving study, followed by an alkaline extraction. The study found that particle size significantly affected the quantity of fiber and cellulose pulp extracted from samples previously dried at 65°C with particle sizes of 300 and 106 μm. Characterization tests revealed variations in the color and texture of the extracted cellulose, attributable to an ineffective delignification stage within the fiber bleaching process. Variations in molecular weight corresponding to 126.32 x 103 g/mol were identified among samples, and FTIR analysis presented a syringyl ring and lignin stretching. Optical microscopy exposed the absence of well-defined regions in the fibers and a readily observable crystalline network. In conclusion, particle size critically influences cellulose extraction from Calamagrostis intermedia, impacting the yield and properties of the resultant product, indicating that further optimization of the extraction and delignification process is required to enhance the quality of the extracted cellulose. Keywords: Calamagrostis intermedia; Particle Size; Cellulose Extraction

Micro-characterization of the adhesion properties and mechanisms at the asphalt-silica aggregate interface under combined thermal-oxygen aging and chloride salt erosion

In this investigation, various Atomic Force Microscopy (AFM) probes were used to characterize changes in the adhesion properties of aged asphalt under different concentrations of chloride salt. The characterization included analyzing the surface morphology, roughness parameters, height-height correlation function (HHCF), and force-distance curves of the asphalt. Additionally, Molecular Dynamics (MD) simulation was employed to reveal the underlying mechanisms that govern changes in adhesion properties between aged asphalt and aggregate when subjected to chloride salt erosion. Interfacial erosion and internal erosion models were constructed to facilitate a comprehensive analysis from multiple perspectives. The results demonstrate that chloride salts interact with the interface between asphalt and silica aggregates, engaging in competitive adsorption with the asphalt. The strength of this competitive adsorption is influenced by the constituents of the asphalt and the concentration gradient of chloride salts both within and outside the asphalt matrix. Under this concentration gradient, polar components are attracted to the asphalt surface by chloride ions, forming triangular adsorption structures with water molecules and aggregates such as asphaltene. Components with lower polarity exhibit distinct distributions and diffusion states due to variations in molecular weight and spatial configuration. As the concentration of chloride salts increases, the concentration gradient intensifies, resulting in enhanced transformations, migrations, and dissolutions of asphalt components. Consequently, the micro-morphology of the asphalt tends to smoothen, the HHCF undergoes significant modifications, roughness decreases, and the adhesion performance between asphalt and aggregate weakens. Moreover, at higher concentrations, the formation of precipitated chloride salt crystals disrupts the continuity of the asphalt, further compromising interfacial adhesion performance. This study is expected to provide theoretical guidance for the modification of asphalt and the improvement of asphalt pavement lifespan in complex service environments.

Structure and microbial-modulating evaluation of a sulfhydryl-modified pectin

In this study, we synthesized a modified form of pectin know as sulfhydryl group (-SH) modified pectin (PSH) by linking cysteine's amino groups and pectin's carboxyl group through amide bonds. The -SH amounts varied from 517 μmol/g to 732 μmol/g. Pectin (PEC) modified with -SH groups showed no significant alteration in chain structure, monosaccharide composition and molecular weight. Compared to PEC, PSH had a stronger interaction with mucus, and the strength of this interaction increased with the -SH amounts. In vitro fermentation indicated that PSH was fermentable by human fecal microbiota, and the -SH modified can prolong the overall fermentation time of PEC from 48 h to 72 h, as evidenced by the variations in pH values, total sugar, molecular weight, monosaccharide consumption and short-chain fatty acids production. Furthermore, microbial analysis revealed that PSH significantly increased the abundance of Faecalibacterium and Bifidobacterium while decreasing the abundance of Klebsiella and Collinsella. These results provided a solid foundation for the potential use of -SH modified PEC as a mucoadhesive material for delivering active substances and regulating the effect of PEC on gut microbiota.

Impact of pendant substituents on post-polymerization functionalization and electronic properties in stereoregular non-conjugated pendant electroactive polymers

Recent reports on non-conjugated pendant electroactive polymers (NCPEPs) have demonstrated the significance of altering structural variables specifically the stereoregularity, the nature of the pendant group and the length of the spacer connecting that group to the backbone for tuning of their optoelectronic properties. The only synthetic approach that allows for selectively studying the effects of tuning these variables without additional superimposed effects of varied molecular weights and tacticities is the post-polymerization functionalization methodology in which parent polymers are synthesized first and then functionalized with the respective pendant groups and spacers. However, specifically for tuning of the pendant group itself, the scope of such post-polymerization functionalization methods remains largely underexplored. Here, the compatibility of the established photochemical thiol-ene post-polymerization method with various pendant groups is investigated for functionalization of stereoregular and stereorandom poly(allyl methacrylates) made via anionic polymerization using an organolithium initiator. Carbazole and a family of four 3,6-disubstituted carbazoles with phenyl, methoxy, nitrile and t-butyl substituents were investigated as the respective pendant groups. With the phenyl, methoxy and nitrile substituted pendant groups limitations of the scope of the thiol-ene methodology due to limited solubility and vulnerability to photochemical side reactions could be demonstrated. In contrast, t-butyl substituents did not impede the post-polymerization functionalization. The corresponding functionalized NCPEPs were characterized and effects of substitution of the carbazole pendant group with t-butyl groups on the optoelectronic properties of the polymers are discussed. Overall, this work demonstrates critical limitations of the thiol-ene functionalization method as well as their origin when applied to differently substituted pendant groups.

Investigation of pressure-controlled injection molding on the mechanical properties and embodied energy of recycled high-density polyethylene

Manufacturing with secondary feedstock has been identified as an effective strategy to improve plastic circularity. However, product quality inconsistencies arise due to variations in molecular weight, rheology, and mechanical properties. This work evaluates the processing of recycled high-density polyethylene using pressure-controlled injection molding with a focus on processing behavior and energy consumption. The effects of injection velocity, packing pressure, and transfer position are benchmarked against a conventional velocity-controlled process. The experimental results show that the novel process control strategy significantly affects the mechanical properties, in-mold rheology, and energy consumption. Parts fabricated using pressure-controlled injection molding showed higher tensile properties due to increased macromolecular orientation. Additionally, reduced energy was used due to lower melt pressures required to completely replicate the cavity geometry. The results demonstrate the potential of the technology to support increased utilization of secondary feedstock and reduced carbon footprint.

Evaluating the applications and effectiveness of magnetic nanoparticle-based hyperthermia for cancer treatment: A systematic review

Magnetic nanoparticle-based hyperthermia as a new cancer treatment technology has been applied for some kinds of tumors. To review the different applications and effectiveness of this new cancer treatment technique, PubMed, Science Direct, Web of Science, and Google Scholar databases were explored up to November 2022, using the following keywords combined in different ways: “Magnetic Nanoparticles Based Hyperthermia”, “Magnetic Nanoparticles” AND “Hyperthermia” AND “Cancer”. The obtained results were screened for the title and abstract and the relevant papers were reviewed for further details. Finally, 24 papers were included in the study. These papers have evaluated the application of magnetic nanoparticle-based hyperthermia for treating different cancers including breast, liver, prostate, pancreas, colon, brain, lung, and stem cell. Various nanoparticles including Iron Oxide (Fe2O3, Fe3O4), Dextran Spermine, Iron Chloride, Magnetic nanoparticles conjugated with Liposomes (MCLs), and Variable Molecular Weight Nanoparticles (VMWNPs) were used in different reviewed studies. The results of reviewed studies revealed that the nanoparticle-based hyperthermia technique as a new progressive modality can significantly improve treatment outcomes for some special cancers. Increasing life expectancy by up to 30% using Iron Oxide magnetic nanoparticle-based hyperthermia for pancreatic cancer and increasing tumor ablation by about 33% for other cancers were reported in reviewed articles. However, further studies are required to extend this new treatment technique to other cancers and for providing more accurate information on nanoparticle-based hyperthermia's effectiveness as a complementary technique in cancer treatment.

The immunomodulatory activity of levan in RAW264.7 macrophage varies with its molecular weights

Levan is a fructose homopolymer obtained from both plants and microorganisms. Microbial levan is typically produced in a variety of molecular weights (MW). Previous studies have shown that different MW of levan exhibit different biological activities. Though levan was reported for its immunomodulatory effect by increasing nitric oxide (NO) production in RAW264.7 macrophage cells, whether its MW can affect this activity remains unknown. In this study, the effect of different levan MW from Bacillus subtilis on its immunoregulatory properties was investigated. B. subtilis was cultivated using various cultivation parameters to obtain levan of different MW. Three weight average MW of levan, >8 × 105 Da (M1), 1.5 × 104 Da (M2) and 3.7 × 103 Da (M3), were selected to test for their effect on modulating NO levels in RAW264.7 cells. Our results showed that M2 increased NO production in a dose-dependent manner, and more effectively than that of M1 and M3. Consistent with these findings, M2 significantly stimulated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) protein expression, while less pronounced effects were observed in the cells treated with M1 and M3. Therefore, our results demonstrate that various MW of levan have varying effects on its immunoregulatory activities in RAW264.7 cells. Furthermore, our findings suggest that the size of levan should be taken into account when employing levan as one of the active ingredients in functional foods and immunomodulatory products.

SAR-AD Method to Characterize Eight SARA Fractions in Various Vacuum Residues and Follow Their Transformations Occurring during Hydrocracking and Pyrolysis

Model compounds were used to provide some chemical boundaries for the eight-fraction SAR-ADTM characterization method for heavy oils. It was found that the Saturates fraction consists of linear and highly cyclic alkanes; the Aro-1 fraction consists of molecules with a single aromatic ring; the Aro-2 fraction consists of mostly 2 and 3-ring fused aromatic molecules, the pericondensed 4-ring molecule pyrene, and molecules with 3–5 rings that are not fused; and the Aro-3 fraction consists of 4-membered linear and catacondensed aromatics, larger pericondensed aromatics, and large polycyclic aromatic hydrocarbons. The Resins fraction consists of mostly fused aromatic ring systems containing polar functional groups and metallated polar vanadium oxide porphyrin compounds, and the Asphaltene fraction consists of both island- and archipelago-type structures with a broad range of molecular weight variation, aromaticity, and heteroatom contents. The behavior of the eight SAR-ADTM fractions during hydrocracking and pyrolysis was investigated, and quantitative relations were established. Intercriteria analysis and evaluation of SAR-ADTM data of hydrocracked vacuum residue and sediment formation rate in commercial ebullated bed vacuum residue hydrocracking were performed. It showed that total asphaltene content, toluene-soluble asphaltenes, and colloidal instability index contribute to sediment formation, while Resins and Cyclohexane-soluble asphaltenes had no statistically meaningful relation to sediment formation for the studied range of operation conditions.