Inherent Molecular Structure Research Articles

Sulfonated polyaniline/MXene composite electrode with high cycling stability for anti-freezing flexible supercapacitor

Polyaniline (PANi) is widely used in supercapacitors owing to its unique structural flexibility and redox behavior. However, due to the limitations of the inherent molecular structure, the expansion and contraction of the PANi skeleton will be triggered during the charging and discharging process, leading to decreased stability and rapid degradation. For this reason, we design a novel sulfonated polyaniline structure of aniline copolymerized with 2-aminobenzenesulfonic acid, thus immobilizing the sulfonic acid group (−SO3H) side chain onto the PANi main chain. The −SO3H acts as a proton reservoir to provide protons for PANi, accelerating the occurrence of redox reactions and providing pseudocapacitance, effectively suppressing the deprotonation phenomenon. Then SPANi is grown in-situ on the interlayers of MXene, which induces the disordered polymer to be ordered on the MXene substrate, forming a 3D interconnected network composite with both high specific capacitance and excellent stability. SPANi/MXene composite has an outstanding specific capacitance of 512.45 F g−1 at 1 A/g and retains up to 92.16 % of the initial capacitance after 10,000 cycles. Assembled with PHEAA-PAA-MXene double-crosslinked organogel electrolyte to form an anti-freezing device with a specific capacitance of 158.63 F g−1, it retains a high specific capacitance of 118.26 F g−1 even under the extreme conditions of −40 °C. The capacitance retention after 10,000 cycles is 95.2 % (20 °C) and 81.82 % (−40 °C), respectively. This work provides simple and effective methods to fabricate high-performance PANi-based electrodes and anti-freezing supercapacitors.

Self-healing and antistatic waterborne polyurethane hybrid coating resulting from hard but reversible Zr-O-Si networks

Robust, self-healing waterborne coatings have become the preferred choice in the field of flexible electronic devices owing to their outstanding compliance, restorability, and environmental friendliness. Nevertheless, most of the existing self-healing waterborne polymers exhibit viscoelasticity, irreversible fatigue damage, and the challenge of reconciling self-healing functions with mechanical properties, all stemming from inherent molecular structure contradictions between flexibility and rigidity. Here, we propose a novel strategy that utilizes a nanofiller with dynamic reversible bonds to overcome the self-healing limitations that theoretically demand flexible chain, for achieving both mechanical robustness and self-healing ability in the waterborne polyurethane (WPU) hybrid coating system. We modified tetrapropyl zirconate (TPOZ) with 3-aminopropyltriethoxysilane (APTES) to enhance compatibility between the matrix and inorganic particles, while the formation of dynamic reversible bonds through both condensation hydrolysis endows the self-healing abilities. The WPU hybrid coating was designed by covalently incorporating amino-modified TPOZ (A-ZrO2) into a glycinamide-functionalized WPU network, conferring excellent fracture energy (50.3 kJ/m2), elastic recovery, along with antistatic capability to the coating. Furthermore, the hybrid coating maintains a robust mechanical performance alongside 92.58 % of healing efficiency, exhibiting a potential for flexible electronics application. The hybridization strategy via incorporation of the nanofillers with hard but reversible covalent bond resolves the inherent robustness-healing trade-off, providing exciting thoughts to expand WPU applications.

Synthesis of sustainable curcumin based photo-crosslinkable benzoxazines: Thermal, hydrophobic and anti-corrosion properties

Bifunctional polybenzoxazines have been developed using sustainable bio-phenol curcumin, paraformaldehyde with varying nature of monofunctional amines through Mannich condensation. The molecular structure of synthesized benzoxazines were confirmed by ATR-FTIR, 1HNMR and 13CNMR and high-resolution mass spectroscopic (HRMS) analyses. DSC thermograms were used to ascertain the curing behaviour of curcumin-based monomers. Thermal curing of Cu-api occurs at 192 °C and that of Cu-aa undergoes dual curing at 177 °C and 209 °C due to its inherent molecular structure. The thermal stability of synthesized polybenzoxazines was studied using TGA, Cu-a exhibits higher char yield of 63% due to higher aromatic content than that of other polybenzoxazines. The occurrence of dimerization (2π+2π cycloaddition) of curcumin based benzoxazines proceeds through conjugation present in the main chain of curcumin when exposed to UV irradiation, and was monitored through UV–visible spectroscopy. All the synthesized benzoxazine monomers were excited within the wavelength of UV range with occurrence of photoluminescence behaviour in visible region ranges between 448 nm and 530 nm. The value of band gap calculated for the curcumin-based monomers ranged from 3.55 to 3.77 eV. The explicit character of curcumin based benzoxazines can be exploited in the field of optical applications. The hydrophobic behaviour of polybenzoxazines was also studied and the highest water interface angle value of 146° was observed for poly(Cu-tfma) due to the presence of fluorine groups. Furthermore, the Cu-tfma coated cotton fabric was tested for its durability and the results indicated that these materials coated cotton fabrics are better suitable for sustainable high performance hydrophobic applications. The anti-corrosion studies indicated that the poly(Cu-api) coated on mild steel exhibits greater resistance towards corrosion amongst the other polybenzoxazines which can be potentially employed as coating in marine environments.

Development of fluorochromic polymer doped materials as platforms for temperature sensing using three dansyl derivatives bearing a sulfur bridge

Three novel bis-dansyl derivatives bearing a sulfur bridge have been synthesized, fully characterized, and their photophysical characterization studied in solution, as well as, in the solid state. All compounds exhibit fluorescence emission with quantum yields up to 60%, which vary significantly depending on the solvent used, and the inherent molecular structure. Moreover, these compounds demonstrate positive solvatofluorochromic behaviour emitting from bluish-green to yellow. Kamlet-Taft studies were performed to better understand the solute–solvent interactions. Due to the intrinsic characteristics of the compounds, efforts were made to understand their potential usefulness for environmental remediation and thus metal ion sensing studies were investigated. Compounds L1 and L2 showed high sensitivity to Cu2+ and Hg2+ ions and were found to modulate their emission extensively, with L2 capable of detecting and quantifying up to 4 µM of Hg2+. Considering the solid-state emission of these compounds, the application towards temperature sensing was put forth. L3 was found to quench its emission in a linear relation with temperature up to 170 °C. Several doped polymer thin films were fabricated, which served as a platform to establish a linear relation with temperature beyond their melting point. Polymethylmetacrylate (PMMA) films emitted up to temperatures of 218 °C, which could be fully restored at room temperature. These results suggest the potential application of these bis-chromophoric compounds as molecular thermometers.

Guidelines for extraction and quantitative analysis of phytosterols and oxidation products

AbstractPhytosterols (PS) are widely distributed in the plant source foods, and research on their health benefits has become increasingly active. This article briefly outlines the main extraction processes of PS and instrumental analysis methods of PS in detail. The PS isolation technique depends on the nature of the matrix and the form of the PS (free, esterified, and glycosylated). Conventional extraction technologies for PS commonly used in practice were Soxhlet extraction and maceration method. Due to their inherent molecular structure, PS exhibits poor stability to heat, light, oxygen, pH, and metal ions. It is of great significance to find a reliable analytical technique to extract PS and oxidation products from food substances and an accurate detection method of PS in different foods due to the instability of plant sterol and the interference of complex plant‐based matrices. Generally, it is common to use GC–MS to determine the composition of total PS and their oxidation products, which requires standard monomer PS. It is desirable to use LC–MS to determine free PS in liquid samples. These methodologies could be meaningful in the quality assessment, health function evaluation, and applications and limitations of plant‐sourced foods.

Coreactant-free dual-emitting conjugated polymer for ratiometric electrochemiluminescence detection of SARS-CoV-2 RdRp gene

Constructing mono-luminophor-based electrochemiluminescence (ECL) ratio system is a great challenge due to the limitations of the luminescent species with dual-signal-output, luminescence efficiency and coreactant. This work developed carboxyl-functionalized poly[9,9-bis(3'-(N,N-dimethylamino) propyl)-2,7-fluorene]-alt-2,7-(9,9 dioctylfluorene)] nanoparticles(PFN NPs) as dual-emitting luminophors, which can synchronously output strong cathodic and anodic ECL signals without any exogenous coreactants. The inherent molecular structure enabled efficient intramolecular electron transfer between tertiary amine groups and backbone of PFN to generate strong cathodic and anodic ECL emission. Particularly, H+ in aqueous solution played an irreplaceable role for cathodic ECL emission. The silver nanoparticles (AgNPs) were developed as signal regulator because of their excellent hydrogen evolution reaction (HER) activity, which significantly quenched the cathodic signal while kept the anodic signal unchanged. The dual-emitting PFN NPs cleverly integrated signal regulator AgNPs and bicyclic strand displacement amplification (SDA) to construct a coreactant-free mono-luminophor-based ratiometric ECL sensing for SARS-CoV-2 RdRp gene assay. The strong dual-emitting of PFN NPs and excellent quenching effect of AgNPs on cathodic emission endowed the biosensor with a high detection sensitivity, and the detection limit was as low as 39 aM for RdRp gene. The unique dual-emitting properties of PFN NPs open up a new path to construct coreactant-free mono-luminophor-based ECL ratio platform, and excellent HER activity of AgNPs offers some new thoughts for realizing ECL signal changes.

Polyimide/crown ether composite film with low dielectric constant and low dielectric loss for high signal transmission.

Dielectric properties of polyimide (PI) are constrained by its inherent molecular structure and inter-chain packing capacities. The compromised dielectric properties of PI, however, could be rescued by introducing trifluoromethyl and forming a host-guest inclusion complex with the introduction of crown ethers (CEs). Herein, we report PI/crown ether composite films as a communication substrate that could be applied under high frequency circumstances. In this work, three kinds of bisphenol A-containing diamine (2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(2-methyl-4-aminophenoxy)phenyl]propane, and 2,2-bis[4-(2-trifluoro methyl-4-aminophenoxy)phenyl]propane) are synthesized and polymerized with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride to prepare low-dielectric PI films by means of thermal imidization. Crown ethers are introduced into the PI with different mass fractions to obtain three series of PI films. Following the combination of trifluoromethyl into the molecular chain of PI, high frequency dielectric loss of modified PI films can be effectively reduced. The properties of these materials (especially the dielectric properties) are thoroughly explored by crown ether addition. The results show that the crown ether addition process can offer crown ethers with increased free volume of PI matrix, thus allowing them to generate a special necklace-like supramolecular structure, which makes the crown ether disperse more uniformly in the PI matrix, resulting in improved dielectric properties. Importantly, the dielectric constant and dielectric loss of the composite films at high frequencies are remarkably reduced to 2.33 and 0.00337, respectively. Therefore, these composite films are expected to find extensive use as a 5G communication substrate at high frequencies in the future.

Hierarchical Nanowire Architectures Self‐Assembled from Ultra‐Deep‐Blue Fluorene‐Based Conjugated Molecules toward Organic Light‐Emitting Diodes with CIEy = 0.06

AbstractOrganic conjugated molecules with a rigid rod‐like π‐backbone structure automatically and easily self‐assemble into an anisotropic nanostructure. However, supersecondary structures obtained from the hierarchical secondary self‐assembly of nanostructures have rarely been reported for non‐amphiphilic conjugated molecules. Here, a nanowire architecture as a supersecondary structure from an ultra‐deep‐blue fluorene‐based conjugated molecule (FCz‐C8‐Am) to improve the emission efficiency and stability is reported. In significant contrast to the four reference molecules, the FCz‐C8‐Am molecules grow into soft nanowires and further self‐assemble into a series of nanowire architectures in the gelation process. This is associated with the synergistic effect of the hydrogen bonds among the amide units, pendant π–π stacking interactions between pendant Cz units, and appropriate soft steric interaction among side‐chains, which are the three design requirements for preparing these nanowire architectures. Interestingly, this supersecondary architecture of FCz‐C8‐Am has a stable ultra‐deep‐blue emission, with an efficiency of ≈77% and a Commission Internationale de L'Eclairage (CIE) value of (0.16, 0.06) in the solid state. These findings provide a profound understanding of the relationship between the inherent molecular structure, supramolecular interaction, and supersecondary nano‐architecture, offering useful information for the development of new functional optoelectronic materials.

Effects of physicochemical and structural properties of single and double feedstuffs derived from different botanic sources on in vitro starch digestion and glucose release kinetics.

Starch is the largest constituent in animal diets. The aims of this study were as follows: (a) to assess the variability of basic physicochemical properties and in vitro starch digestion of starchy feedstuffs and investigate relationship between physicochemical properties and starch digestion of the feedstuffs, and (b) to explore the effects of different sources of starchy feedstuffs on starch digestion and glucose release. In this study, we determined the inherent molecular structure and granular structure of starch and chemical compositions of seven starchy feedstuffs, as well as starch digestion in single feedstuff and different feedstuffs combined with corn. Scanning electron microscope (SEM) results revealed significant difference between granule shape and size of starch of different feedstuffs. Fourier transforms infrared (FTIR) spectra for barley and wheat had lower (p<0.05) absorbance band at areas A_860 and A_928 than other feedstuffs, yet rice starch had the lowest value for ratio (R) (1047/1022). Moreover, digestion rate ranged from 0.0157/min for resistant starch (sorghum) to 0.029/min for rapidly starch (broken rice). The principle component analysis (PCA) showed that predicted glycaemic index (pGI) was positively related to A_1022, glucose and rapidly (RDS) content and negatively related to A_995, A_1047, R (1047/1022), resistant starch (RS) and amylose content. Most of the feedstufss with corn combination had no effect on rate of starch digestion. In addition, different starchy feeds and corn combination changed the rate of starch digestion, when barley, however, sorghum combined with corn seemed to affect rate of starch digestion. To sum up, different sources differed in basic physicochemical and structural properties, which would influence the digestion rate of starch and the release of glucose. Combination of different feedstuffs particular sorghum with corn has interactive effect on starch digestion and the release of glucose.

Comparative study on the removal of different-type organic pollutants on hierarchical tetragonal bismutite microspheres: Adsorption, degradation and mechanism

Abstract By selecting three typical dyes with different charge properties as model pollutants, the inherent roles of adsorption, degradation pathways and mechanism of using bismutite (Bi2O2CO3) photocatalyst to remove organic pollutants from aqueous solution were systematically studied. Bismutite can effectively degrade dyestuffs [e.g., anionic dye methyl orange (MO), amphoteric dye rhodamine B (RhB), cationic dye methylene blue (MB), and their mixed solutions]. Degradation kinetics are diverse when treating different types of dyes, which is possibly because of their significantly different adsorption behavior on bismutite. The inherent molecular structure, charge properties of dyes, and attraction between dye and bismutite may particularly dominate degradation efficiency. Moreover, h+ and · O2− were main active species for MO and RhB degradation, whereas rich adsorption of MB on bismutite significantly inhibited the separation of electron-hole pairs and thus · OH was dominant for MB degradation. According to the intermediates generated during the reaction, the degradation pathways of three dyes were proposed. This study revealed the adsorption and photocatalytic behavior of different-type dyes on the tetragonal bismutite catalyst, which facilitates in understanding the degradation processes and mechanism of different-type organic pollutants and promotes the practical application of bismutite in complex wastewater purification.

A novel organic-inorganic hybrid complex based on Cissus quadrangularis plant extract and zirconium acetate as a green inhibitor for mild steel in 1 M HCl solution

An organic-inorganic hybrid complex based on Cissus quadrangularis (CQ) plant extract and zirconium acetate (CQ-ZrAc) was synthesized, characterized and studied as a novel green inhibitor against mild steel corrosion in 1 M HCl solution using gravimetric analysis, potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The corrosion inhibition effect of the complex was also compared with CQ. GC–MS and FTIR studies were conducted to assess the active organic species and the functional group present in the extract which caused its adsorption on the mild steel surface and lead to complex formation with ZrAc. The gravimetric parameters revealed that inhibition efficiency depends both on the temperature of corrosive solution and inhibitors concentration. Adsorption of both CQ and CQ-ZrAc follow Langmuir adsorption isotherm. PDP analysis suggests that both compounds act as a mixed type of inhibitor. EIS data revealed the formation of a protective film by the adsorption of active species present in the extract. SEM images show better morphology in presence of CQ-ZrAc complex as compared to CQ. UV–visible and FTIR results indicate a good interaction between inhibitors and mild steel surface. Density functional theory has been carried out to correlate the inhibition efficiency with inherent molecular structure and parameters. Analysis of variance statistically compare the difference existing between inhibition efficiencies from gravimetric, PDP and EIS technique and suggests that they are not significantly different.

Protein molecular structure in relation to predicted biodegradation and nutrient supply of feedstocks and co-products from bio-oil processing with CNCPS system: Comparison Crusher Plants within Canada and within China as well as between Canada and China

Recently, rapid non-invasive advanced vibrational molecular spectroscopy has been developed to detect tissue inherent molecular structure. However, this advanced technique is seldom known by animal scientists and seldom used to study feed molecular structure in relation to nutrient utilization and availability in animals. The objectives of this study were to 1) detect the interactive association between the processing-induced protein molecular structure changes and biodegradation and intestinal digestion in ruminants using advanced vibrational molecular spectroscopy, and 2) develop a model to predict protein and carbohydrate degradation and digestions based on feed inherent protein molecular structure. The feed used for this study were various sources of feedstock (oil seeds) and co-products (canola meal, canola pellets) from ten different crushing plants in Canada and China with multi-source samples from each crushing plant. The predictable protein and carbohydrate degradable sub-fractions and nutrient supply of sub-fractions to dairy cows were evaluated with the updated Cornell Net Carbohydrate and Protein System (CNCPS 6.5). The protein molecular structure was revealed using advanced vibrational molecular spectroscopy (FT/IR-ATR). The molecular structure spectral analyses were carried out using uni- and multi-variate molecular spectral analyses. The model variable selection was carried out using SAS with a Stepwise option. The results showed that protein molecular structure spectral characteristics could be used to predict CNCPS protein and carbohydrate nutrient supply to dairy cows. Strong positive correlation was found in canola meal between rumen degraded PA2 and amide I area (r = 0.67, P < 0.001), amide I height (r = 0.73, P < 0.001), and α-helix height (r = 0.83, P < 0.001). RDPB2 was negatively correlated with α-helix height (r = −0.69, P < 0.001). Moreover, TRDC was negatively correlated with amide I area (r=-0.64, P < 0.001), amide I height (r = −0.65, P < 0.001), and α-helix height (r = −0.62, P < 0.001). It was concluded that protein and carbohydrate degradable and undegradable sub-fractions had interactive associations with the processing-induced protein molecular structure changes in co-products from bio-oil processing.

Molecular Structure of Feeds in Relation to Nutrient Utilization and Availability in Animals: A Novel Approach

Abstract The invention and development of new research concepts, novel methodologies, and novel bioanalytical techniques are essential in advancing the animal sciences, which include feed and nutrition science. This article introduces a novel approach that shows the potential of advanced synchrotron-based bioanalytical technology for studying the effects of molecular structural changes in feeds induced by various treatments (e.g., genetic modification, gene silencing, heat-related feed processing, biofuel processing) in relation to nutrient digestion and absorption in animals. Advanced techniques based on synchrotron radiation (e.g., synchrotron radiation infrared microspectroscopy (SR-IMS) and synchrotron radiation X-ray techniques) have been developed as a fast, noninvasive, bioanalytical technology that, unlike traditional wet chemistry methods, does not damage or destroy the inherent molecular structure of the feed. The cutting-edge and advanced research tool of synchrotron light (which is a million times brighter than sunlight) can be used to explore the inherent structure of biological tissue at cellular and molecular levels at ultra-high spatial resolutions. In conclusion, the use of recently developed bioanalytical techniques based on synchrotron radiation along with common research techniques is leading to dramatic advances in animal feed and nutritional research.

Fabrication of Noncoplanar Molecule Aggregates with Inherent Porous Structures for Electrochemiluminescence Signal Amplification.

A simple and time-saving strategy was developed for the amplification of electrochemiluminescence (ECL) by dropping the noncoplanar tetraphenylethylene (TPE) solution on the surface of gold electrode. The self-assembled TPE aggregates exhibited inherent porous structures, endowing them with high specific surface area and oxygen adsorption capability. Therefore, the fabricated porous structures could lead to a 50-fold increase in the ECL signal of luminol in neutral aqueous solution, in comparison to that on the bare electrode. In contrast, the aggregates of the two typical coplanar polycyclic aromatic hydrocarbons (PAHs), perylene and pyrene, gave a weaker ECL enhancement, owing to their disc-like molecular structure and densely packed layers under aggregated conditions. The proposed ECL system has been successfully applied for the detection of hydrogen peroxide (H2O2) in the linear range of 0.25-1000 μM with a detection limit (S/N = 3) of 0.1 μM. Our findings provide inspiration for revealing the role of inherent molecular structure in the aggregate configuration, and they provide attractive perspectives for the usage of noncoplanar molecules in analytical applications.

Detect unique molecular structure associated with physiochemical properties in CDC varieties of oat grain with unique nutrient traits [Feed Type vs. Milling Type] in comparison with barley grain using advanced molecular spectroscopy as a non-destructive biological tool

The objective of this study was to determinate grain unique protein inherent molecular structure that are related physiochemical and nutrient profiles in CDC developed oat varieties [CDC Nasser (Feed Type) and CDC Seabiscuit (Milling Type)] grown in cool climate condition in western Canada in comparison with conventional barley variety of CDC Meredith as a control using advanced molecular spectroscopy. Multivariate analyses, including an agglomerative hierarchical cluster analysis (CLA) and principal component analysis (PCA), were performed to identify protein molecular structural differences among the grains. The results revealed that CDC Seabiscuit contained greater (P < 0.05) protein structural Amide I and II than CDC Nasser and CDC Meredith, while the greater (P < 0.005) structural Amide I to II area and height ratios was detected in CDC Meredith. New oat grains had greater (P < 0.05) β-sheet height than barley grains, however, there was no difference in α-helix to β-sheet ratio values among the varieties. In conclusion, CDC Nasser and CDC Meredith had no difference in protein molecular structural features, while CDC Seabiscuit contains different protein structural characteristics as compared to CDC Meredith grain. The molecular structure features are highly associated with physiochemical and nutrient profiles in grains, which indicate that it also affect nutrient utilization and availability.

On a molecular basis pelleting-induced changes on carbohydrate structure of co-products from bio-oil production revealed with vibrational molecular spectroscopy plus chemometrics: Sensitivity and response to conditioning temperature and time

Molecular structure changes are closely related to nutrient utilization and availability. However, so far little research was found to determine the processing induced changes on carbohydrate structure in co-products from bio-oil processing. The objectives of this study were to investigate synergistic effects of conditioning temperature (70, 80 and 90°C) and time (50 and 75 s) during the pelleting process on carbohydrate structure profile of the co-products from bio-oil processing (canola meal). The vibrational molecular spectroscopy (ATR-VMS) with chemometrics was used to determine the impact of pelleting at different conditions on the inherent molecular structure changes. The molecular spectral analyses, Univariate and Multivariate spectral analyses, were used in this study. Multivariate spectral analyses included cluster analysis and principal analysis. The chemical functional groups mainly associated with carbohydrate structure profile in this lipid-free co-products (or with very little lipid) included cellulosic compounds (CEL, ranged at ca. 1302-1186 cm −1 ), structural CHO (SCHO, ranged at ca. 1488- 1186 cm −1 ) and total CHO (TCHO, ranged at ca. 1193-879 cm −1 ). The results showed that the pelleting process was able to alter inherent structures of CHO functional groups in the co-products from bio-oil processing. The univariate molecular analysis indicated that spectral intensities of CHO functional groups in the co-products were significantly affected by the pelleting process in the current study ( P< 0.05). Altering processing conditions resulted changes in molecular structure features of CHO functional groups except TCHO. The results of multivariate spectral analysis of CHO indicated that inherent CHO structural characteristics of all functional groups were not fully distinguished. This study demonstrated that the pelleting process under the conditions investigated caused partial changes in carbohydrate structures in terms of the spectral features of specific functional groups. These changes were not sufficient enough to make the entire spectral region of CHO functional groups become fully distinguishable. Future research is needed to investigate the interactive relationships between the absorption intensities of carbohydrate functional groups (TCHO, SCHO, CEL) and biodegradation and digestion of the co-products in order to reveal how carbohydrate molecular structure changes induced by processing affect nutritive availability.

(Invited) Efficient Electrocatalysts for Alcohol Oxidation and Oxygen Reduction in Alkaline Solutions

Alkaline fuel cells have some advantages as compared with conventional acid fuel cells. Our research group has investigated the possibility of alkaline fuel cells using anion-exchange membrane as an electrolyte. In the presentation, I would like to introduce and discuss about some topics relating to alkaline fuel cells as follows: 1) Direct oxidation fuels: alcohols We have been focusing on ethylene glycol as a direct fuel in anion-exchange membrane fuel cells (AEMFCs). Ethylene glycol has superior energy density (7.56 kWh dm−3) and higher boiling point (471 K) than some typical alcohol fuels such as methanol and ethanol. The oxidation of ethylene glycol in alkaline medium is faster than that in acid medium. And, surprisingly, ethylene glycol provides larger oxidation currents than methanol and polyols such as glycerol, erythritol, and xylitol in alkaline solutions. Thus, ethylene glycol is a promising fuel for AEMFCs, which overcomes a conventional direct methanol fuel cell (DMFC). Ethylene glycol has the above-mentioned advantageous features as DAFCs’ fuel, but it has a crucial problem derived from its inherent molecular structure. Ethylene glycol is a C2 molecule having a C−C bond in its structure. C−C bond is a stumbling block for electroorganic chemists since thus C−C bond is comparatively strong and cannot be easily cleaved. As well as ethanol oxidation, ordinal Pt catalyst cannot achieve the complete oxidation of ethylene glycol, and leaves some intermediate products. Therefore, in order to increase the efficiency of fuel utilization, active catalysts, having sufficient ability to break C−C bond in ethylene glycol, are strongly required. To our best knowledge, there is no available literature concerning the oxidation of ethylene glycol to CO2from an electrocatalytical view point. Here we introduce an effective C−C bond cleavage electrocatalyst for ethylene glycol. 2) Oxygen reduction catalysts: non-precious metal catalysts Electrochemically reduction of oxygen is an essential reaction involving in fuel cells. Among the various kinds of electrocatalysts, Pt, Pt-alloy, Ag are known to be fairly active for oxygen reduction in alkaline solutions. Precious metals, however, have some serious problems to be overcome before worldwide spread of fuel cells, such as economical cost, reproducibility and limited resources. These problems motivated many researchers to study for alternative catalysts besides a standard catalyst of Pt/C. Among proposed alternative catalysts, perovskite-type oxide is one of the promising candidates as a non-precious metal catalyst. Since Meadowcroft pointed out the catalytic activity of lanthanum-cobalt oxide for oxygen reduction, perovskite-type oxides become attractive materials as electrocatalysts for many electrochemists. However, the detailed mechanism for oxygen reduction on perovskite-type oxide electrodes has not been fully clear yet. We investigated the oxygen reduction on perovskite-type oxides using thin film electrodes and single crystal electrodes, and shed lights on the catalytic roles of oxides and carbon additives.

Continuous dynamic analysis: evolution of elastic properties with strain

Abstract

Molecular spectroscopic investigation on fractionation-induced changes on biomacromolecule of co-products from bioethanol processing to explore protein metabolism in ruminants

Fractionation processing is an efficient technology which is capable to redesign/redevelop a new food or feed product with a specified chemical and nutrient profile. This processing technique was able to produce four different fractions (called “A”, “B”, “C”, “D” fractions/treatments) with different nutrient profile form a co-product of bioethanol processing [wheat dried distillers grains with soluble (DDGS)]. To date, there is no study on the effect of fractionation processing on inherent molecular structure of different fractions and how the processing-induced structural change affect the metabolic characteristics of protein and nutrient availability. The objectives of this experiment were to: (1) investigate the effect of fractionation processing on changes of protein functional groups (amide I, amide II, and their ratio) and molecular structure (modeled α-helix, β-sheet, and their ratio), and (2) study the relationship between the fractionation processing-induced changes of protein molecular structure and nutrients availability as well as the metabolic characteristics of protein. The hypothesis of this study was that the fractionation processing changes the molecular structure and such changes affect the metabolic characteristics of protein. The protein molecular structure spectral profile of the fractions A, B, C and D were identified by Fourier-transform infrared attenuated total reflection spectroscopy (FT/IR-ATR). The results showed that the fractionation processing significantly affected the protein molecular spectral profiles. The differences in amide I to amide II peak area and height ratios were strongly significant (P<0.01) among the treatment fractions, ranging from 4.98 to 6.33 and 3.28 to 4.00, respectively. The difference in the modeled protein α-helix to β-sheet ratio was also strongly significant (P<0.01) among the treatment fractions. Multivariate molecular spectral analysis with cluster (CLA) and principal component analyses (PCA) showed that there are no clear distinguished clusters and ellipses among the fractions (A, B, C and D) in the protein amide I and II region ca. 1726–1485cm−1. The correlation study showed that the modeled α-helix to β-sheet ratio tended to have a negative correlation with truly absorbed rumen undegraded protein (ARUPDVE: r=−0.944, P=0.056<0.10) and total truly absorbed protein in the small intestine (DVE: r=−0.946, P=0.054<0.10), but there was no correlation between the α-helix to β-sheet ratio and the degraded protein balance (DPBOEB: P=0.267<0.10). In conclusion, the fractionation processing changed the molecular structural spectral profiles in terms of amide I to II ratio and α-helix to β-sheet ratio. These changes negatively affected the metabolic characteristics of protein and true protein supply. These results indicated that spectral features of different fractions could be used as a potential tool to predict true protein nutritive value.

Using Synchrotron Radiation-Based Infrared Microspectroscopy to Reveal Microchemical Structure Characterization: Frost Damaged Wheat vs. Normal Wheat

This study was conducted to compare: (1) protein chemical characteristics, including the amide I and II region, as well as protein secondary structure; and (2) carbohydrate internal structure and functional groups spectral intensities between the frost damaged wheat and normal wheat using synchrotron radiation-based Fourier transform infrared microspectroscopy (SR-FTIRM). Fingerprint regions of specific interest in our study involved protein and carbohydrate functional group band assignments, including protein amide I and II (ca. 1774–1475 cm−1), structural carbohydrates (SCHO, ca. 1498–1176 cm−1), cellulosic compounds (CELC, ca. 1295–1176 cm−1), total carbohydrates (CHO, ca. 1191–906 cm−1) and non-structural carbohydrates (NSCHO, ca. 954–809 cm−1). The results showed that frost did cause variations in spectral profiles in wheat grains. Compared with healthy wheat grains, frost damaged wheat had significantly lower (p < 0.05) spectral intensities in height and area ratios of amide I to II and almost all the spectral parameters of carbohydrate-related functional groups, including SCHO, CHO and NSCHO. Furthermore, the height ratio of protein amide I to the third peak of CHO and the area ratios of protein amide (amide I + II) to carbohydrate compounds (CHO and SCHO) were also changed (p < 0.05) in damaged wheat grains. It was concluded that the SR-FTIR microspectroscopic technique was able to examine inherent molecular structure features at an ultra-spatial resolution (10 × 10 μm) between different wheat grains samples. The structural characterization of wheat was influenced by climate conditions, such as frost damage, and these structural variations might be a major reason for the decreases in nutritive values, nutrients availability and milling and baking quality in wheat grains.