Search

Herbal bioactive compounds have captured pronounced attention considering their health-promoting effects as well as their functional properties. In this study, the binding mechanism between milk protein bovine β-lactoglobulin (β-LG), oleuropein (OLE) and safranal (SAF) found in olive leaf extract and saffron, respectively via spectroscopic and in silico studies. Fluorescence quenching information exhibited that interactions with both ligands were spontaneous and hydrophobic interactions were dominant. Also, the CD spectroscopy results demonstrated the increase in β-sheet structure and decrease in the α-helix content for both ligands. Size of β-LG-OLE complex was higher than β-LG-SAF due to the conformation and larger molecular size. Molecular docking and simulation studies revealed that SAF and OLE bind in the central calyx of β-LG and the surface of β-LG next to hydrophobic residues. Lastly, OLE formed a more stabilized complex compared to SAF based on the molecular dynamic simulation results.

The molecular size and shape for 27 diamondoids molecules (adamantanes and alkyladamantanes, diamantine and alkyldiamantanes) were calculated by computational quantum mechanical modeling method of dispersion correction B3LYP-D3/6-311+G**, in which the family of adamantanes presents molecular sizes in terms of width of 6.8–7.9 A, and for the family of diamantanes 6.8–7.4 A, in terms of length the size for adamantanes are 7.6–9.5 A and for diamantanes 9.3–10.0 A and in terms of height are rounded from 7.4 to 9.6 A for adamantanes and 7.4 to 8.5 A for diamantanes. This size depends on the alkyl substitution either in CH2 or CH bridgehead positions. A measure of spherical shape deviation in terms of ovality, (O = 1 for sphere shape) was calculated, in which for adamantane, methyladamantanes, dimethyladamantanes, and multi-substituted adamantanes, is 1.17, 1.21, 1.24, and 1.26–1.31, respectively and ovality value for diamantane is 1.20 and 1.22–1.27 for methyl substituted diamantanes. Ovality (shape) and molecular size differences between adamantane, methyladamantanes, dimethyladamantanes, multi-substituted adamantanes, and the corresponding diamantanes allow suggesting a dynamic model for separation from the linear alkanes in a mixture into a slit pore shape typical for microporous carbons.

Ozone is an interesting alternative for modifying starch, as it is considered an emerging and environmentally friendly technology. New applications for food ingredients are receiving attention, such as 3D printing. Consequently, the impact of emerging technologies on new applications must be understood. In this work, cassava starch was modified by ozone to evaluate its printability. Increasing ozonation time produced a starch with higher carbonyl and carboxyl contents, lower pH and molecular size, and gels with different behaviors (stronger and weaker than the native ones, as a function of processing time). The hydrogels obtained were evaluated in relation to pasting and gel properties, including their printability. The effects of starch concentration, gelatinization temperature and storage period were also evaluated. Starch ozonated for 30 min showed the lowest peak apparent viscosity at all the temperatures and starch concentrations evaluated, and provided the strongest gel. Gels produced by native starches and starches ozonated for 30 min showed good printability when the gelatinization temperature used was 65 °C, but up to this temperature, only starch ozonated for 30 min produced gels with good printability. This work highlights that, by using the ozone process to modify starch and varying the process conditions, it is possible to obtain hydrogels with enhanced pasting properties, gel texture, and printability, thereby expanding the potential of starch applications.

Confined fluids undergo substantial changes in terms of their physicochemical properties when the pore radius reduces to the nanometric scale and be comparable to the molecular size. Adsorptions, which are the corresponding changes in the concentration of a given fluid at the interface compared with the other contacting phase, strongly affect the vapour-liquid equilibrium (VLE), especially in nanopores. No published literature so far has been found to study the critical shifts of confined fluids with adsorptions in nanopores. In this study, first, the van der Waals (vdW) and Soave-Redlich-Kwong (SRK) equations of state (EOSs) are extended to calculate the VLE of confined fluids in nanopores. Second, a new empirical correlation is developed to calculate the fluid adsorption thickness in nanopores. Finally, two generalized analytical formulations, on a basis of the modified vdW and SRK EOSs, are initially proposed to calculate the shifts of critical temperatures and pressures by considering the fluid adsorptions in nanopores. All the extended EOSs, new adsorption correlation, and two generalized formulations have been validated to be accurate by comparing with the experimental or literature data. Overall, the critical properties of the confined fluids are found to shift more with adsorptions in nanopores. Moreover, the compressibility factors of the confined Lennard–Jones fluids are proven to be universal and independent of the pore radius effect.

Zeolites with ordered porous structure of molecular size are widely employed as commercial adsorbents and catalysts. On the other hand, the zeolite matrix is regarded as an ideal scaffold for hosting coordinatively unsaturated sites. Remarkable achievements have been made dealing with the construction, characterization and catalytic applications of coordinatively unsaturated sites in zeolite matrix. Herein, a literature overview of recent progresses on this important topic is presented from the specific view of coordination chemistry. Different strategies to construction coordinatively unsaturated sites in zeolite matrix, in zeolite framework or extraframework positions, are first introduced and their characteristics are compared. Then, spectroscopic techniques to determine the existing states of cation sites and their transformations in zeolite matrix are discussed. In the last section, the catalytic applications of coordinatively unsaturated sites in zeolite matrix for various important chemical transformations are summarized.

This study investigated polycyclic aromatic hydrocarbons (PAHs) and soot formation characteristics in laminar jet flames fuelled by primary reference fuels (PRFs) at elevated pressures. Qualitative PAHs and quantitative soot profiles were acquired by using laser-induced fluorescence and laser-induced incandescence, respectively. The backpressure of flames ranged from 1 bar to 5 bar. Proper flames with the volume fraction of iso-octane in PRFs varying between 0% and 100% and flame equivalent ratio varying between 3.0 and 11.4 were stabilised in a pressurised chamber. The effects of backpressure, equivalent ratio and iso-octane ratio on PAHs and soot formation were evaluated. PAHs and soot formation can be promoted by increasing iso-octane ratio, equivalent ratio and backpressure. The data suggest that PAHs with large molecular size are more sensitive to the increase of backpressure compared with those with small molecular size. Backpressure played a positive role in the growth of PAHs size. The averaged soot volume fraction showed an approximate power-law relation with pressure. The measured averaged soot volume fraction was proportional to pn. Pressure exponent n was 1.34–2.17, 1.41–2.12 and 1.56–2.20 at equivalent ratios of 6.2, 8.5 and 11.4, respectively.

In this work, an accurate model is presented for predicting the hydrogen hydrate cage occupancies. This novel predictive method is based on the hydrate phase stability and hydrogen effective molecular size and configuration. The hydrogen-hydrogen interactions in a hydrate cage are calculated using the Kihara potential and the pairwise additivity rule. The accuracy and reliability of the proposed method are evaluated by comparison with various literature data. The model shows that the small cage double occupancy of structure II is possible if the volume expansion of the cages has been taken into account and a slight change in the volume of small cages leads to a considerable decrease in pressure required for double occupancy of small cages. The model also indicates that the large cages volume expansion has a weaker effect on the required pressure for quadruple occupancy in comparison with the case of double occupancy of small cages. The proposed model confirms the findings of most of the previous experimental observations and theoretical simulations.

Non-glutinous rice is always less sticky than glutinous rice. By soaking two non-glutinous rice (Jingmi and Xianmi) with different concentrations of NaOH solution, the stickiness of cooked non-glutinous rice is significantly increased, which is closely associated with the removal of surface proteins of these treated rice grains. By investigating starch leaching characteristics and the molecular structure of leached starch, we find: (i) total solids and amylopectin amount in the leached materials increase by raising NaOH concentration; (ii) the molecular size and chain-length distributions (CLDs) of leached starch significantly differ between samples with different soaking treatments; (iii) a strong correlation between stickiness of cooked rice and total amount of leached amylopectin is established. (iv) molecular causes for the increased stickiness of alkali-soaked rice are put forward to explain the above observations. This study could broaden the applications of non-glutinous rice by altering its stickiness attribute with alkali soaking.

Heparan sulfate (HS) and heparin, representative members of the glycosaminoglycans, possess distinct biological functions in terms of their specific interactions with hundreds of binding proteins. However, the structural properties of HS and heparin are complex due to their variable repeating motifs, different chain lengths and sulfation patterns. A concise chemoenzymatic approach has been developed to obtain well-defined low molecular weight (LMW) HS analogues. Pasteurella multocida heparosan synthase-2 (PmHS2) was utilized to fabricate the HS backbones with controllable chain lengths ranging from 14mer to 26mer. Moreover, regioselective and overall sulfation were conducted by chemical approach. The persulfated HS analogues exhibited more potent beta-site amyloid precursor protein (APP)-cleaving enzyme-1 (BACE-1) inhibitory activity than heparin and enoxaparin, and enhanced BACE-1 inhibitions were also found with the increasing molecular size of the HS analogues. This approach supplies the promising LMW HS analogues for the potential development of novel anti-Alzheimer's drugs.

The herbal medicines have been popularized throughout the globe since time immemorial. Several plant based therapeutic leads have been produced through integrated approaches. Many herbal bioactives have several health benefits but limited therapeutic potential due to short half-life and low bioavailability profile. Plant derived molecules are either hydrophilic or lipophilic in nature. Highly hydrophilic bioactives have poor absorption via lipid membrane which slows down their biological efficacy and pharmacokinetics. The large molecular size of the plant bioactive compounds also limited their therapeutic uses due to low membrane permeability. Nanocarriers have the ability to potentiate the efficacy of herbal bioactives by improving their solubility, absorption profile, minimizing dose and side effects. The nanoemulsions can channel the herbal bioactives to the particular target site and maintain blood-plasma concentration for longer periods. However, the conventional drug delivery system failed to achieve these specific requirements. Nanoemulsions are promising to improve solubility, stability, permeability and bioavailability of the herbal bioactives through encapsulation. The present review describes the importance of nanoemulsions for delivery of herbal bioactives and highlights the various aspects of its formulation consideration, challenges and future perspective for the development of herbal bioactives.

We perform single-molecule flow experiments using confocal microscopy and a microfluidic device for shear rates up to 20,000 s−1 and present results for the shear-induced unraveling and elongation of tethered von Willebrand factor (VWF) multimers. Further, we employ companion Brownian dynamics simulations to help explain details of our experimental observations using a parameterized coarse-grained model of VWF. We show that global conformational changes of tethered VWF can be accurately captured using a relatively simple mechanical model. Good agreement is found between experimental results and computational predictions for the threshold shear rate of extension, existence of nonhomogenous fluorescence distributions along unraveled multimer contours, and large variations in extensional response behaviors. Brownian dynamics simulations reveal the strong influence of varying chain length, tethering point location, and number of tethering locations on the underlying unraveling response. Through a complex molecule like VWF that naturally adopts a wide distribution of molecular size and has multiple binding sites within each molecule, this work demonstrates the power of tandem experiment and simulation for understanding flow-induced changes in biomechanical state and global conformation of macromolecules.

The purpose of this study was to characterise the production of exopolysaccharide (EPS) by indigenous lactic acid bacteria (LAB) isolated from traditional Algerian dairy products and to evaluate their possible use in agri-foods. Among the collection of isolated strains, the strain Weissella confusa (W4) was selected for its ability to produce EPS once exposed to a sucrose culture medium. EPS produced were first isolated with a standardised method and further characterised in terms of molecular size, antioxidant activity, and rheological properties. Its direct implication in the texture and syneresis of acid milk gel was evaluated offering interesting industrial applications for its use during processes dealing with dairy products.

Graphite has been currently considered as a promising cathode material in dual ion batteries (DIBs) due to its unique features of sp2 hybridized carbon and stacked two-dimensional layered structures. However, unexpected volume/thickness changes in the graphite cathodes, induced by the intercalation/deintercalation of anions with large molecular size have been known to be a critical problem in designing DIB cells. To understand the volume/thickness changes in the DIB electrodes, in operando optical observing apparatus has been employed to observe the cross-section view of a graphite-based cathode upon cycles in the present work. The observation suggests that the cathode initially presented a huge irreversible thickness change (60%), and such thickness variation was prone to reduce and remain

It is well known that natural organic matter (NOM) is the major precursor of disinfection by-products (DBPs) when inadequately removed NOM reacts with the disinfectant during chlorination and chloramination. Special interest in the DBP precursors is justified as it is essential to understand the reactivity and character of the precursors responsible for the formation of DBPs. This is vital in order to develop processes that will enhance precursor removal during drinking water treatment. The aim of this study was to investigate the impact of the characteristics of NOM within an oligotrophic water source on the formation of trihalomethanes (THMs) during drinking water treatment at Rand Water. Specific ultraviolet absorbance (SUVA) and molecular size distribution (MSD) were the main NOM characterisation techniques utilised during this study. The MSD was investigated by making use of high-performance size-exclusion chromatography (HPSEC). The MSD results showed a significant correlation between the high-molecular-weight (HMW) fraction of NOM and TTHM formation, specifically during the summer months. The positive correlation existing between SUVA and full scale NOM removal indicates that SUVA can be used to indicate NOM treatability during water treatment. A link between chloroform formation and the HMW fraction of NOM was also observed; however, the formation of bromodichloromethane (BDCM) was not due to the HWM fraction, as indicated by a weak regression coefficient. The results displayed are an indication that the aromatic fraction of NOM was the main precursor to TTHM formation, more prominently during summer.

Effects of ultrasound treatment (20 kHz, 41–45 W cm−2, 0, 20, 40 or 60 min) on the physicochemical, functional properties and elements of the secondary structure of transglutaminase (TGase)-crosslinked whey protein isolate (WPI) exposed to prior thermal treatment (75 °C, 15 min) were investigated. The largest molecular size of proteins in the TGase-crosslinked WPI was observed after the ultrasound and thermal pre-treatment (HU-WPI-TGase). HU-WPI-TGase had the maximum intrinsic fluorescence intensity, with highest loss of free amino groups. Ultrasound-treated WPI (U-WPI) showed more (13%) emulsifying activity and more (63%) foaming ability than untreated WPI, but HU-WPI-TGase had higher foam stability and lower emulsifying activity than U-WPI. FTIR analysis indicated that ultrasound, heat treatment and TGase cross-linking had effects on the β-sheet, β-turn and random coil of WPI. The outcomes from this study show a potential application in providing novel functional ingredients for the dairy industry.

[EN] Extra-large pore zeolites are a small subset (21) among the whole list of 253 zeolites available. The discovery of new low-glycemic sugars is very attractive as new healthy additives in the food field. This is the case of the 6-kestose. In the present case, it appears in a mixture in aqueous solution together with sucrose, the separation of the mixture being necessary. For this, we have focused on using certain zeolites with adequate pore sizes that allow the separation of this mixture, considering that since the molecular size of 6-kestose is greater than sucrose, it is necessary to promote the sorption of the latter, so that the first can be purified. After a computational screening of micropores of the 253 IZA zeolites, 11 zeolites were selected. Of these, 3 extra-large pore zeolites (AET, DON, ETR) have been proposed, which were analyzed in-depth through a molecular dynamics study considering the external surface. The results show that DON presents the most promising theoretical results for a selective sucrose/6-kestose separation., We thank MICINN of Spain for funding through projects RTI2018101784-B-I00, RTI2018-101033-B-I00, SEV-2016-0683 as well as ASICUPV and CESGA for computational facilities. IBL and PGI gratefully acknowledge CSIC for a JAE-Intro fellowship. AM thanks Generalitat Valenciana for the predoctoral fellowship GRISOLIAP/2019/084.

Impact of extrusion pretreatment (50, 70, 90, 110 and 130 °C) on physicochemical, emulsifying properties and water holding capacity (WHC) of transglutaminase (TGase) cross-linked whey protein isolate (WPI) were investigated in this study. The results of molecular size distribution and SDS-PAGE proved that there were more macromolecular polymers formed in TGase cross-linked WPI after extrusion pretreatment (E-WPI-TGase) and the consumption of free amino groups for E-WPI-TGase was the largest at the extrusion temperature of 50 °C and 70 °C. As the extrusion temperature increased from 90 °C to 130 °C, particle size of WPI after extrusion pretreatment (E-WPI) was not changed significantly, compared with that of E-WPI-TGase (p > 0.05). In addition, the emulsifying properties, surface hydrophobicity and WHC of E-WPI-TGase were higher than those of WPI cross-linked by TGase (WPI-TGase) (p

White wheat salted noodles containing oats have a slower digestion rate those without oats, with potential health benefits. Oat β-glucan may play an important role in this. Effects of sheeting and shearing during noodle-making and subsequent cooking on β-glucan concentration, solubility, molecular size and starch digestibility were investigated. The levels of β-glucan were reduced by 16% after cooking, due to the loss of β-glucan into the cooking water. Both the noodle-making process and cooking increased the solubility of β-glucan but did not change its average molecular size. Digestion profiles show that β-glucan in wholemeal oat flour did not change starch digestion rates compared with isolated starch, but reduced the starch digestion rate of oat-fortified wheat noodles compared to the control (wheat noodles). Confocal laser scanning microscopy suggests that interaction between β-glucan and protein contributes to the starch-protein matrix and changes noodle microstructure, and thus alters their digestibility.

Predicting of corrosion inhibition potential of organic compounds from the outcomes of experimental and computational studies is gaining meticulous interest. A proper understanding of substituents or electronic effect helps in designing of successful inhibitors before their experimental trials and expensive as well as hazardous syntheses. Recently, worldwide research in corrosion science is intended for the designing of such effective molecules based on the knowledge derived from previously published reports. Addition of polar substituents in the molecular structure of organic compounds enhances their hydrophilicity thereby the corrosion inhibition potential. Nevertheless, despite of their solubility enhancement property, some of the substituents, especially electron withdrawing (EW) substituents, decrease the corrosion inhibition potential. Generally, the addition of polar substituents brings two types of effect, namely, electronic or substituents effect that concerns the change in electron density at donor sites and molecular size effect which talks about the effect of molecular size on metal surface coverage capabilities. The present review article is intended to describe in what conditions electronic effect and/or molecular size effect will operate. The effect on solubility, orientation and hydrophilicity/ hydrophobicity of organic corrosion inhibitors is described herein in association with their corrosion inhibition performance.

Structural descriptors take the central place in the digitalization of chemical reactions. Information entropy is one of such descriptors that has been a seminal for numerous derivative indices. Previously, we have studied the rules of calculating information entropies of molecular ensembles based on the corresponding values of constituting molecules and found that the complexity of the ensemble has the contributions from the molecular structure and the size of the molecules. Considering chemical reaction as the conversion of one molecular ensemble to another allows calculating the change in information entropy as well as its components associated with molecular-structure and molecular-size changes. We demonstrate that both total information entropy change and its contributions are characteristic for the selected classes of chemical reactions and exemplify this approach with the cycloaddition and exchange reactions widespread in organic chemistry.

Tailoring porosity of pitch-based activated carbons (PACs) on a large scale is of high importance and usually achieved by introducing additives or templates and adjusting activation conditions. Since pitch is a kind of extraordinarily complex mixtures, it is highly necessary to investigate the effect of pitch composition on pore structure of PACs. Herein, a coal-tar pitch was subdivided by solvent fractionation into toluene-soluble (TS), pyridine-soluble (PS), quinoline-soluble (QS), and quinoline-insoluble (QI) fractions followed by activation using KOH or steam, respectively, to obtain PACs. It is found that the formation of pores in PACs is significantly dependent on pitch composition and activation methods. The light fractions (TS and PS) are more favorable for pore development in the KOH-activated carbons, whereas pores in the H2O-activated carbons are easily achieved by using the heavy fractions (QS and QI). The possible pore-formation mechanisms were also proposed, which indicates that the big differences intrinsically originate from the chemical properties (such as molecular size, structures, reactivity with activation agents and rheological behaviors of the molecular aggregations) of pitch compositions. When commercial pitches are employed for the precursors, a synergistic effect on pore development occurs both in KOH- and H2O-activated PACs seriously depending on their mass percentages of light or heavy fractions. It suggests that the mass percentage can be an index to foresee the porous properties of PACs. These findings open up a significantly important and more practical approach applicable to tailor the pores in PACs on an industrial scale just through adjusting pitch compositions.

Fundamental knowledge of physicochemical properties of polymeric food materials is of practical importance in food and pharmaceutical industry. Effects of water, molecular weight, and lactose addition on glass transition temperature (Tg), α-relaxations, and relaxation time (τ) of amorphous poly (vinyl pyrrolidone) (PVP) and maltodextrin (MD) were studied at various aw and 25 °C. Water sorption behaviour of amorphous PVP and MD was Mwavg–dependent at aw ≤ 0.44, whereas the molecular size effects dominated the sorption process of MD at aw ≥ 0.56 and 25 °C. Fractional water sorption was confirmed in studied polymers/lactose mixtures at aw ≤ 0.44 in molecular scale, whilst collapsed structure of above mixtures were observed at aw ≥ 0.44 during storage up to 20 days at 25 °C. Despite of the calorimetric onset Tg of amorphous polymers/lactose mixtures showed a composition-independent at aw ≤ 0.44, Tg, α-relaxation, and τ of PVP and MD were disturbed by water, molecular weight and size, and adding lactose. Structural strength (S) of PVP was determined by its molecular weight at aw ≤ 0.44, whereas molecular size dominated the S of MD at 0.44 ≤ aw ≤ 0.76 due to water migration. The changes of aw and lactose addition significantly disturbed the S of studied polymers. Moreover, a combined use of water sorption isotherm and the relationship of S and aw gave a quantitative measurement of compositional effects and could be used to control the physicochemical properties of amorphous food polymers, such as collapse.

Pyrodextrins were prepared by heating waxy maize starch at 170°C and pH 3.0 for 0.5, 1, 2, 3 and 4h. Structural changes of pyrodextrins were determined by gel permeation chromatography and 1H NMR. Gelatinization and retrogradation of pyrodextrins were measured by differential scanning calorimetry. The water solubility of pyrodextrins increased from 48.9 to 99.4% as heating time increased from 0.5 to 4h. The molecular size, melting enthalpy of pyrodextrin, and the degree of retrogradation decreased as pyrodextrin solubility increased. The level of 1,6-anhydro-β-d-glucopyranose increased from 2.6 to 4.0% as the heating time increased from 0.5 to 4h. The degree of branching (DB) of pyrodextrins was increased from 8.8 to 14.4%, and the average chain length (CL) reduced from 7.2 to 4.6. The increased level of new bonds and DB combined with reduced CL during the dextrinization explained the reduced extent of retrogradation of the pyrodextrin.

Octenylsuccinate starches were obtained by combining esterification reaction and β-amylase hydrolysis treatment with (HOSE) and without (OSE) acid pretreatment. In the present study, the emulsions stabilized by gum Arabic (GA), OSE and HOSE starches were systematically compared in terms of molecular structure and emulsion properties. The molecular structure of three emulsifiers was analyzed using size exclusion chromatography, showing that the GA had a relative smaller molecular size distribution compared to OSE and HOSE starches. Emulsifying activity index (EAI), emulsifying stability index (ESI), droplet size (d4,3) of emulsions at different emulsifier to oil ratios were determined to evaluate the emulsion properties of three emulsifiers under a wide range of pH and NaCl concentration. The GA stabilized emulsion showed the lowest droplet size at high emulsifier concentrations, but clear phase separation was observed after 7 days of storage at relatively low emulsifier concentrations (1:9 and 0.5:9.5). The emulsions stabilized by the HOSE starch showed excellent emulsion stability under a wide range of pH and NaCl concentration, and produced the small droplets with better storage stability, particularly at relatively low emulsifier concentrations (1:9 and 0.5:9.5).

Large-scale, functional collective motions of proteins and their supra-molecular assemblies occur in a physiological solvent environment at finite temperatures. The solution of these motions with standard molecular dynamics algorithms is computationally hardly possible when considering macromolecules. Much research has focused on alternative approaches that use coarse-graining to model proteins, but mostly in vacuum. In this paper, we incorporate realistically the physical effects of solvent damping into the finite element model of proteins. The proposed framework is based on Brownian dynamics and shown to be effective. An important advantage of the approach is that the computational cost is not dependent on the molecular size, which makes the long-time simulation of macromolecules possible. Using the proposed procedure, we demonstrate the analysis of a macromolecule in solvent—an analysis that has not been achieved before and could not be performed with a molecular dynamics algorithm.

Current therapy for ovarian cancer typically involves indiscriminate chemotherapies that can have severe off target effects on healthy tissue and are still plagued by aggressive recurrence. Recent shifts towards targeted therapies offer the possibility of circumventing the obstacles experienced by these traditional treatments. While antibodies are the pioneering agents in targeted therapies, clinical experience has demonstrated that their antitumor efficacy is limited due to their high immunogenicity, large molecular size, and costly and laborious production. In contrast, nucleic acid based chemical antibodies, also known as aptamers, are ideal for this application given their small size, lack of immunogenicity and in vitro production. As aptamers have begun to demonstrate their promise through targeting Epithelial Cell Adhesion Molecule (EpCAM), as well as a number of ovarian cancer biomarkers, in in vivo and in vitro models, their clinical applicability is slowly being realised. This review explores some of the current progress of aptamers targeting cancer biomarkers and their potential role as ovarian cancer therapeutics.

Herein, the Keggin structural phosphotungstic acid (HPW) has been successfully encapsulated within hollow microporous polymer nanospheres (H-MPNs) by a “ship-in-bottle” approach. The H-MPNs are formed by self-assembly induced by hyper-crosslinking of polylactide-b-polystyrene (PLA-b-PS). The obtained catalysts (HPW@H-MPNs) exhibit more sustainable availability than the previously reported HPW-supported catalysts in esterification reaction. This excellent sustainability can be attributed to the stable microporous channels in H-MPNs which are smaller than the molecular size of HPW, thereby effectively preventing the HPW from leaking out. Moreover, such catalysts also perform well in terms of catalytic activity and universality because of the combination of a hollow structure in the interior and permeable pore channels in the shells. This type of polymer carrier and general encapsulation method may provide a new strategy for developing more sustainable catalysts for various chemical reactions.

Graphene nanosheets (GNS) such as graphenes and graphene oxides (GOs) have been widely investigated as next-generation adsorbents in both water and wastewater treatment processes due to their unique physicochemical properties and their affinity towards different classes of organic contaminants (OCs). In the last five years, more than 40 articles investigating adsorption of different classes of OCs by graphene and GO were published in peer-reviewed journals. Adsorption mechanisms were controlled by molecular properties of OCs (e.g., aromatic vs aliphatic, molecular size and hydrophobicity), characteristics of adsorbents (e.g., surface area, pore size distribution, and surface functional groups), and background solution properties (e.g., pH, ionic strength, surfactants, NOM, and temperature). This literature survey includes: (i) a summary of adsorption of OCs by GNS, (ii) a comprehensive discussion of the mechanisms and factors controlling the adsorption of OCs by GNS and a comparison of their adsorption behaviors with those of CNT. This literature survey also identifies future research needs and challenges on the adsorption of OCs by GNS.

The structure features (both molecular size and chain-length distribution) of leached starch during rice cooking are of prime importance to the stickiness of cooked rice. In the present study, the effects of cooking temperature (thermodynamic effects) and cooking time (kinetic effects) during rice cooking on the structural features of leached starch are explored using different rice varieties in terms of amylose content. We show that (i) the molecular sizes of the leached starch at varying conditions are mainly distributed between 1 and 100 nm, while the chain-length distribution of leached starch at varying conditions are ranged at DP 1–1000, displaying significantly different structural features with the starch in the whole grain; (ii) the effects of cooking temperature on these structural features are cultivar-specific, and much more significant than the effects of cooking time, indicating that the molecular size and chain-length distribution of leached starch during rice cooking are controlled by thermodynamic effects, rather than kinetic effects; (iii) the leached amylose content of non-waxy rice varieties increase with the cooking temperature increasing, revealing that it is small amylopectin easier to leach out of rice kernel, instead of amylose. These molecular structural characterizations provide new understandings of starch leaching and leached starch in terms of improving the cooking and eating quality of cooked rice.

While polysaccharides are the most abundant biomacromolecules widely distributed in nature, little is known in their chemical structures and functional mechanism. Compared with DNA and protein, polysaccharides possess more complex structures and composition with various molecular size, conformational shape and charge characteristic. Currently, the lack of a uniform and clear consensus of polysaccharide purity leads to low accuracy of structural analysis. In the present study, a new theory on polysaccharide purification named as “relative ordered structure” was proposed, which was used to purify the water-extracted polysaccharides from Hypsizygus marmoreus (SHMP), successfully giving five purified sub-fractions. Results showed that their major chemicals were similar, while molecular weights, monosaccharide compositions, surface morphology, solution properties as well as their structural features enormously varied. Methylation and 1D/2D NMR analysis indicated the presence of α-glucans, fucomannogalactans and galactoglucan in SHMP, further confirming the feasibility of this theory in isolation and purification of natural polysaccharides. Based on the results and previous reports, this work aims to introduce and generalize the “relative ordered structure” theory. Altogether, structural characterization of polysaccharides cannot simply “copy” the techniques on protein, more theories and methodology applicable to polysaccharide itself should be established.

Graphene quantum dots (GQDs) are emerging zero-dimensional materials promising a spectrum of novel applications, for example, for bioimaging owing to their desirable properties including tunable photoluminescence, high photostability, good biocompatibility, and molecular size. In this study, carboxylated single-crystalline GQDs with high brightness are synthesized using a bottom-up approach. And for the first time, GQDs are conjugated with monosaccharide moieties and employed to reveal the distribution and dynamic trafficking of carbohydrate receptors on live cells.

Carbohydrates and ginsenosides in ginseng are biologically interrelated. Their synchronous analysis is therefore essential in chemical research on ginseng to characterize its "holistic" quality. Here we investigated the processing chemistry of red ginseng (RG), a ginseng product processed by water-steaming, for which both carbohydrates and ginsenosides were qualitatively and quantitatively determined through multiple analytical techniques. Results revealed that the steam-processing not only qualitatively and quantitatively altered the ginsenosides but also affected the polymeric carbohydrates via changing their physiochemical parameters, i.e. water-solubility, molecular size, types and ratios of constituent monosaccharides. Potential mechanisms involved in the transformation of ginseng chemicals are proposed and discussed, including hydrolysis (deglycosylation, demalonylation, deacetylation), dehydration, polymerization, volatilization, reduction and the Maillard reaction. The study strengthens the research on the processing chemistry of RG, and therefore should be helpful for elucidating the scientific basis of RG preparation and application.

The objective of this study is mainly to investigate the interaction between CRM and asphalt binder in asphalt mixtures added with CRM in dry process during the time period after mixing and before paving, including the storage in silo. High pressure-gel permeation chromatographic (HP-GPC) and Fourier transform infrared spectroscopy (FTIR) tests were used on extracted binders from the asphalt mixtures stored in the oven at four time phases of 0, 30, 60, 90 min at the temperature of 160 °C. The results showed that (1) the percentage of the large molecular size (LMS) from GPC test increased as the storage time of the mixtures in dry process increased, and could reach that from wet process; (2) the ratio of bonding at C O, an aging index from FTIR, had a sharp increase from storage time 0–30 min, and kept less change for further storage; (3) increase in LMS as storage time increase could be mainly caused by the interaction of CRM with the asphalt, not by aging.

This study evaluated the effectiveness of antioxidant (AO) on retarding aging of asphalt mixture using the large molecular size (LMS) of gel-permeation chromatogram (GPC) technique. A polymer stabilizer (designated as KL) and a hydrated lime (HL) were used for preparing dense-graded asphalt (DGA) mixes to examine the effect of the AOs on age retardation. The asphalt mixtures prepared with and without AO were aged artificially in two stages; the short-term aging (SA) for one hour at 160 °C and the long-term aging (LA) for one week at 76 °C. The LMS values were used in the statistical test for estimation of age retardation effect of the AOs and for predicting absolute viscosity. It was found that the KL and HL were effective for inducing reduction of aging significantly at α = 0.05 after SA and LA. Therefore, it was found that the LMS, which was obtained by GPC test, was a dependable variable that can be used for evaluation of age retardation. It was also observed that the KL and HL did apparently have an effect of reducing the AV, predicted by LMS, after SA and LA.

The combination of ZIFs with semiconductor materials is expected to get multi-functional hybrid materials with synergistic effects of the individual components. ZnO/ZIF-8 composites with blocklike structure were synthesized via a hydrothermal method. The dark and illuminated current density of the ZnO/ZIF-8 photoelectrodes is greatly decreased compared with pure ZnO. Opposite changes of photocurrent response are observed with addition of hole scavengers with different sizes, which verifies the molecular size selectivity of photoelectrochemical (PEC) response of ZnO/ZIF-8 composite. This novel composite may be potentially developed into a new-type of PEC sensors with molecular size selectivity.

Mobilities of polyatomic molecule ions in helium gas were measured at 85 K and room temperature using a low-temperature drift tube. They differed from the typical behavior shown by atomic or small molecular ions in helium owing to the influence of attractive interactions among the molecular ions and also their size and shape. To investigate the relationship between ion size and mobility, we measured the mobilities of CH 3 O + , C 2 H 5 O + , and C 3 H 7 O + .

Adsorption equilibria of imidazolium-based ionic liquids (ILs), [Omim]Cl, [Hmim]Cl and [Bmim]Cl, onto activated carbon from aqueous solutions were measured using a dynamic fixed-bed method at temperatures from 303 to 323 K. The measured amount of adsorbed IL increased with an increase in alkyl chain length of cation as [Omim]Cl > [Hmim]Cl > [Bmim]Cl, and this trend can be explained by hydrophobicity of the IL. The amount of adsorbed ILs decreased with an increase in temperature and ranged from 0.70 to 0.61 mmol/g-adsorbent at a concentration of 1.2 mol/m3 for the case of [Omim]Cl. Fitting parameters in the Dubinin-Astakhov (DA) equation determined with correlation of the experimental data, E (interaction energy between IL and adsorbent) and q0 (saturated adsorption amount of IL), increased with an increase in the alkyl chain length of cation, and that could be clearly related to the physicochemical properties of the IL such as hydrophobicity and molecular size. Analysis of adsorption equilibrium data with the DA equation allows design of adsorption processes for ILs.

This study aimed to assess solar photocatalytic activity of Fe-doped TiO2 specimens for the degradation of natural organic matter (NOM) represented by a model humic acid (HA). Fe-doped TiO2 specimens (P-25 and UV-100) were prepared by a wet impregnation method. Humic acid (molecular size

Nowadays there is a great interest in investigating the effect of particular hyaluronan fragments in the biomedical field and in cosmeceutical applications. Literature has reported that very low molecular weight HA (Mw&nbsp

The content and composition of rice kernels are closely related to the textural properties of cooked rice. In this study, the mechanistic explanations of textural changes were linked to proton mobility, leaching behavior, and the molecular features of rice components during cooking. The decreasing trend of hardness and the formation of stickiness was mainly determined by the molecular mobility of components. The molecular weight (Mw) of starch and protein in leached solids increased with the leaching at 70–100 °C. The Mw of rice kernels at different cooking temperatures and times was similar, but the molecular size and volume varied at different stages of cooking. The dismission of the crystalline structure, C1 resonance, and lamellar structures after cooking at 100 °C for 10 min indicated that the structural evolution of starch in rice kernels was time- and temperature-dependent. These results provide a promising foundation for developing strategies to control rice cooking.

Chalcone [(E)-1,3-diphenyl-2-propene-1-one], a small molecule with α, β unsaturated carbonyl group is a precursor or component of many natural flavonoids and isoflavonoids. It is one of the privileged structures in medicinal chemistry. It possesses a wide range of biological activities encouraging many medicinal chemists to study this scaffold for its usefulness to oncology, infectious diseases, virology and neurodegenerative diseases including Alzheimer’s disease (AD). Small molecular size, convenient and cost-effective synthesis, and flexibility for modifications to modulate lipophilicity suitable for blood brain barrier (BBB) permeability make chalcones a preferred candidate for their therapeutic and diagnostic potential in AD. This review summarizes and highlights the importance of chalcone and its analogs as single target small therapeutic agents, multi-target directed ligands (MTDLs) as well as molecular imaging agents for AD. The information summarized here will guide many medicinal chemist and researchers involved in drug discovery to consider chalcone as a potential scaffold for the development of anti-AD agents including theranostics.

Rice milling is a very common process to improve rice edible quality. In this study, the effects of the degree of milling (DOM) on starch leaching characteristics and its relation to rice stickiness were investigated. As DOM increased, the whiteness of rice grains and rice stickiness increase, while the protein and lipid content of rice grains decreases. By examining the starch leaching characteristics during rice cooking, it shows that i) increasing DOM significantly increases the total solids and leached starch content while decreases the leached protein content; ii) the molecular size and chain-length distribution (CLD) of leached starch are not significantly varied between rice samples with different DOM, but are significantly different from that of native starch; iii) a significant correlation between rice stickiness and leached amylopectin amount is established; iv) the molecular mechanism for the increased stickiness as affected by DOM is also proposed. The improved understanding of rice processing obtained in this study may allow a better control of rice eating quality.

This study investigated the physicochemical and functional characteristics of citric acid (CA)-treated whey protein isolate (WPI) by dynamic high-pressure homogenization (DHPH) at different pressure levels (0, 25, 50, 75, and 100 MPa, 3 cycles). The number of macromolecular polymers increased in CA-treated WPI with DHPH at 0–100 MPa by the analysis of molecular size distributions. DHPH can reduce the particle size of WPI and CA-treated WPI. Additionally, the content of free sulfhydryl groups and surface hydrophobicity of WPI and CA-treated WPI increased after DHPH treatment (p

Previous studies have suggested that water-soluble polysaccharides from fermented carrot pulp (WSP-p) have stronger anti-diabetic effects than those from un-fermented carrot pulp (WSP-n). This study aimed to improve understanding of these functional differences by comparing their molecular structures. Weight-average molecular weights of WSP-p fractions were lower than those of the corresponding WSP-n fractions. While both WSPs had similar functional groups, more fragmented particles were observed on the surface of large particles of WSP-n than WSP-p. Monosaccharide composition and methylation analysis confirmed that both WSP-p and WSP-n were pectic polysaccharides, containing rhamnogalacturonan-I-type polysaccharides with 1,4-linked α-d-galacturonic acid residues and homogalacturonan regions with 1,4-GalpA linkages. 1H and 13C NMR showed that they had similar linkage patterns. These findings suggested that probiotic fermentation of WSP mainly cleaved the linkages between repeating units, and resulted in less polydisperse molecular size distributions.

Whereas non-extractable residue (NER) formation is recognized as an important process affecting the ecological risk of organic contaminants in soils, it is commonly neglected in regional-scale multi-media models assessing chemical environmental fate and risk. We used a combined field and modeling study to elucidate the relative importance of NER formation to the reduction in available organic contaminants compared with fate processes commonly considered in risk assessment models (volatilization, leaching, and biodegradation). Specifically, four polycyclic aromatic hydrocarbons (PAHs), i.e., phenanthrene (Phe), pyrene (Pyr), benzo[a]pyrene (BaP), and benzo[ghi]perylene (BghiP), were spiked and measured in a one-year field pot experiment at four sites with diverse environmental conditions on the eastern Tibetan Plateau. The rate of NER formation was derived as the difference between the overall rate of decline in total-extractable PAH concentrations, obtained by fitting a biphasic first-order model to the measured concentrations, and the sum of the calculated rates of volatilization, leaching, and biodegradation. Our work shows that the total-extractable PAH concentration undergoes a rapid decline and a slow decline, with shorter overall half-lives (especially for BaP and BghiP) than those observed in earlier studies. Generally, NER formation was assessed to be the dominant contributor (64 ± 33%) to the overall decline of PAHs, followed by biodegradation (35 ± 32%); volatilization and leaching were the smallest contributors. In particular, heavier PAHs (i.e. BaP and BghiP) tend to have shorter half-lives in the rapid and the overall decline phase, indicating that the erroneous estimation of environmental fate and risks might be more pronounced for organic contaminants with a large molecular size. The trend of overall decline rates of PAHs displayed a combined effect of NER formation and biodegradation. This work indicates the need to consider NER formation as a process in multi-media models of chemical fate and risk.

Screening of potential hydrate promoter/inhibitor species is essential in the investigation of clathrate hydrates in many areas of industrial interest. However, experimental analyses do not yield sufficient information to determine whether molecular size, dipole moment, molecular mass, or any other parameters influence the thermodynamic stability of clathrate hydrates in general. The present contribution employs a mutual information-based nonparametric statistical analysis to identify trends in a multivariate data set for 21 clathrate hydrate formers. It is showed through the introduction of a simple correlation that prediction of the heat of dissociation of a clathrate hydrate may be sufficient to predict the entire phase equilibrium curve above the ice point. The dipole moment and molecular volume of hydrate forming species influence the dissociation pressure curve, and distinctive behaviours may be observed for cyclic gas species as compared to non-cyclic species.

Few studies have been conducted to examine the spatial heterogeneity of riverine sediment organic matter (SOM) at the molecular level. The present study explored the chemical and molecular heterogeneity of alkaline-extractable SOM from riverine sediments via multiple analytical tools including molecular composition, absorption and fluorescence spectra, and molecular size distributions. The riverine SOM revealed complex and diverse characteristics, exhibiting a great number of non-redundant formulas and high spatial variations. The molecular diversity was more pronounced for the sediments affected by a higher degree of anthropogenic activities. Unlike the cases of aquatic dissolved organic matter, highly-unsaturated structures with oxygen (HUSO) of SOM were more associated with the spectral and size features of humic-like (or terrestrial) substances than aromatic molecules were, cautioning the interpretation of the SOM molecules responsible for apparent indicators. Noting that a higher detection rate (DR) produces fewer common molecules, the common molecules of 23 different SOMs were determined at a reasonable DR value of 0.35, which accounted for a small portion (5.8%) of all detected molecules. They were mainly CHO compounds (>98%), which positively correlated with spectral indicators of biological production. Despite the low abundance, however, the ratios of aromatic to aliphatic substances could be indexed to classify the common molecules into several geochemical molecular groups with different degrees of the associations with the apparent spectral and size indicators.

This research aimed to investigate fine structural changes and pasting properties of isolated rice starches during pre-germination. Three stages of pre-germinated brown rice (PGBR) and flour were prepared from three different Thai paddy cultivars. Changes in α-amylase activities of flour were determined. Starch was isolated from the flour by alkali extraction. The molecular size distributions, amylopectin branch chain length distributions, and pasting properties of three-stage PGBR starches were compared to ungerminated brown rice (UGBR) starches. During pre-germination, the α-amylase activities of PGBR flour from all rice cultivars were increased. Isolated UGBR starches from the three rice cultivars had higher starch yields than three-stage PGBR starches. HPSEC-RI results showed different molecular size distributions; the amylose contents of KDML105 and RD31were reduced from 15.5 to 12.7% and 18.6 to 15.8% at the 1st and 2nd stages of pre-germination, respectively. HPAEC-PAD results indicated that isolated three-stage PGBR starches from three rice cultivars had lower short A chains amylopectin branch chains than their UGBR starches. Pre-germination affected pasting properties in which the peak viscosities changed at the 1st stage of pre-germination for RD6 (3662 cP) and the 2nd stage of pre-germination for KDML105 (3860 cP) and RD31 (2279 cP) cultivars.

In the 1940s, research by Baker established fundamental aspects of the breadmaking process while Finney showed that differences of quality resided in the gluten proteins of flour. Different lipid components have been found to affect loaf volume and texture but variation in lipid composition of current wheat varieties does not account for significant quality differences. Fundamental studies by Tipples and Kilborn showed that optimum dough development had two requirements – a critical mixing intensity and a critical amount of imparted energy. Expansion of a fermenting dough depends on two stabilizing mechanisms resulting from the gluten/starch matrix and the liquid lamellae surrounding the gas bubbles. In the 1970s, wheat cultivars were developed with poor baking properties, related to a dearth of insoluble protein, shown to comprise glutenins of large molecular size. Research by Payne and co-workers revealed that dough strength could be related to glutenin subunits and the genes controlling their synthesis. This has opened up new directions for determining composition-quality relationships and, in turn, has enabled strategies to be devised for improving quality based on wheat genetic composition.