Fourier Transform Infrared Results Research Articles

Low Dielectric Properties and Transmission Loss of Polyimide/Organically Modified Hollow Silica Nanofiber Composites.

In this study, a series of low dielectric constant and transmission loss of polyimide (PI)/organically modified hollow silica nanofiber (m-HSNF) nanocomposites were synthesized via two-step polymerization. Two different PIs were fabricated using two types of diamine monomers with or without fluorine-containing groups and biphenylene structure of dianhydride. The chemical structure and morphology of the fabricated composites were characterized using Nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and field-emission scanning electron microscopy (FESEM). The two-step polymerization process successfully manufactured and converted from polyamic acid to polyimide after thermal imidization was proved by the NMR and FTIR results. The FESEM and their related energy-dispersive X-ray spectroscopy (EDS) images of nanocomposites indicate that the m-HSNF is extremely dispersed into the polyimide matrix. The high-frequency dielectric constants of the nanocomposite materials decrease as the presence of fluorine-containing groups in diamine monomers and the loadings of the m-HSNF increase. These findings are probably attributed to the presence of the steric hindrance effect brought by trifluoromethyl groups, and the m-HSNF can disrupt the chain packing and increase the free volume, thus reducing the dielectric properties of polyimides. The transmission loss and its related uncertainty of fabricated composite materials contain excellent performance, suggesting that the fabricated materials could be used as substrate materials for 5G printed circuit board.

Microstructure and Antibacterial Properties of Chitosan-Fe3O4-AgNP Nanocomposite.

The goal of this research is to synthesize and characterize Fe3O4@Chitosan-AgNP nanocomposites in order to determine their antibacterial activity. The research methods include the synthesis of Fe3O4@Chitosan-AgNP nanocomposites, as well as the characterization of nanoparticles using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) analysis, and subsequent antibacterial activity tests. The study’s findings demonstrated the successful synthesis of Fe3O4@Chitosan-AgNP nanocomposites, followed by nanoparticle characterization using SEM, TEM, XRD, and FTIR. Based on the XRD results, the conjugation of Fe3O4@Chitosan-AgNP nanocomposites has been successfully formed, as evidenced by the appearance of characteristic peaks of Fe3O4, chitosan, and AgNPs. According to the FTIR results, the interaction between chitosan-AgNPs and conjugated Fe3O4 occurred via the N atom in the NH2 group and the O atom in the OH group, and C=O. The SEM and TEM images also show that the Fe3O4@Chitosan-AgNP conjugation is a nanoparticle-based composite material. The combination of nanocomposites Fe3O4@Chitosan-AgNPs has antibacterial activity, inhibiting the growth of bacteria such as Bacillus cereus and Escherichia coli.

SYNTHESIS, CHARACTERIZATION AND EQUILILBRIUM STUDY OF NITRIC ACID MODIFIED ACTIVATED CARBON ADSORBENT FROM BAMBOO CULMS

This study evaluated the synthesis of low cost activated carbon adsorbent from waste bamboo culms collected at a construction site around Auchi Polytechnic, modified with environmentally friendly nitric acid for enhanced pore structures and improved adsorption versatility. The material was characterized by Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET), energy dispersive X-ray (EDAX) and nickel adsorption. The FTIR result showed the characteristics O–H stretching of free hydroxyl and strong hydrogen bond group on the activated carbon surface. The BET surface area of the activated carbon displayed high specific surface area of 1.087 ×103 m2/g and 71.41% mesoporosity, despite the lower activation temperature of 600 oC. The maximum adsorption capacity of the activated carbon for nickel was 20.69 mmol/g. Freundlich isotherm model best explained the adsorption behavior, suggesting heterogeneous surface adsorption due to textural properties of the activated carbon or ionic interaction between nickel molecule and the functional groups. Nitric acid modified activated carbon is a promising adsorbent candidate for heavy metal removal. Keywords: Bamboo culms, nitric acid, adsorbent, modified, characteristics.

Effect of Water Soaking on the Microstructure and Spontaneous Combustion Characteristics of Bituminous Coal During Low−Temperature Oxidation

ABSTRACT The effects of water soaking on the microstructure and spontaneous combustion characteristics of coal samples were investigated by scanning electronic microscopy (SEM), Fourier transform infrared (FTIR) spectrometer, and temperature programmed testing system (TPTS). The SEM results showed that the pore structures on the surface of water−soaked coal were more developed than raw coal, the pores increased and enlarged, and the phenomenon of water absorption swelling occurred. At the same time, water soaking had a certain influence on the functional groups in coal. The results of FTIR clearly illustrated that the surface functional groups of water−soaked coal were more active, and the contents of functional groups such as hydroxyl, methylene, aliphatic ether and aromatic ether all increased to varying degrees. During the low−temperature oxidation process, the analysis results of TPTS indicated that the oxygen consumption rate and the production of CO, C2H4, and other gases of water−soaked coal were higher. Based on the analysis method of CO, CO/CO2 and C2H4 gas growth rate, the three peaks of the curve obtained correspond to the characteristic temperatures of each oxidation stage of the coal samples. The critical temperature, dry cracking temperature and fission temperature of water−soaked coal were 60 ± 10 ℃, 90 ± 10 ℃ and 120 ± 10 ℃, respectively, which was 10 ℃ lower than raw coal. The apparent activation energy (E a) of coal was calculated by the CO model and fitted in sections. It can be seen that the E a of water−soaked coal at different stages of low−temperature oxidation was lower, and the maximum difference was 2.1 kJ/mol. Therefore, from the above results, it inferred that the activity of bituminous coal became stronger after soaking in water, which may be due to the effect of soaking on the surface structure and active groups of coal, thus showing a higher risk of spontaneous combustion.

Biosynthesis of gold Nanoparticles by Lyngbya sp. Clone Zen / Mira 16S ribosomal RNA gene and its antibacterial activity

Different methods to biosynthesis of Gold nanoparticles was done with using cyanobacterium Lyngbya sp. , and salt gold (HAuCL4) and evaluate their antibacterial activity .Gold nanoparticles were prepared in different ways ,dry and fresh weight of this cyanobacterium to obtain aqueous extract. The synthesized nanoparticles were characterized using analytical techniques such as UV-Visible spectroscopy, SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared) and XRD (X-Ray Diffraction). UV-visible spectroscopy show a Surface Plasmon Resonance (SPR) peak at (532- 552) nm; confirmed by (SEM) image revealed the spherical shape and the size range from (39.1-61.9) and (59.4-84.0) nm for dry, wet aqueous extract respectively. FTIR result showed containing of ( phenol ,protein and carbonyl) as afunctional group. The crystalline nature of the nanoparticles was evident from Peaks in the (XRD) pattern. biosynthesis

Pengaruh Komposisi Kitosan Terhadap Sifat Fisis Dan Biodegradable Film Komposit Nanoserat Pinang Dengan Castor Oil Sebagai Plasticizer

Research has been carried out on the effect of chitosan composition on the physical and biodegradable properties of areca nut nanofiber composite films with castor oil as a plasticizer. Samples were made using the solution casting method. The variations of chitosan used were 0 g, 0.56 g, 0.7 g, 0.84 g, 1.4 g and one sample used starch with a variation of 0.84 g chitosan. The physical properties of the samples tested were thickness test, FTIR test and FESEM test. Mechanical properties tests include tensile strength, elongation, elasticity, and biodegradation tests. The samples were characterized using a Particle Size Analyzer (PSA) to determine the size of the nanofibers, a Field Emission Scanning Electron Microscope (FESEM) to determine the sample morphology and Fourier Transform Infrared (FTIR) to determine the functional groups. PSA results showed that the nanofibers had a diameter of (79-187) nm. The results of FESEM characterization obtained the shape of a hollow biodegradable plastic surface. The FTIR results indicate the presence of a C=O functional group and C-O is a hydrophilic functional group which indicates that biodegradable plastic is capable of being degraded. The best tensile strength results in the chitosan variation of 0.84 g without starch with a value of 20.04 MPa, the best elongation in the 0.7 g chitosan variation with a value of 138.56%, elasticity 198.66 MPa in the 0.84 g chitosan variation with the addition of starch, the average thickness is 0.25 mm. The higher the variation of chitosan, the thickness, tensile strength, elasticity, and biodegradation of biodegradable plastics increase, while elongation decreases

Development of saga (Abrus precatorius) seed extract as a green corrosion inhibitor in API 5l Grade B under 1m HCL solutions

The critical role of newly green corrosion inhibitors shows the disruption of cathodic and anodic reactions at the metals and solution interface. The object of this study is the development of Saga as a corrosion inhibitor to mitigate the effect of corrosive HCl 1M оn mild steel. The inhibitor was extracted using methanol to prepare various concentrations. Fourier transform infrared (FTIR) spectroscopy was used to determine the functional group of the inhibitor. The electrochemical impedance spectroscopy aided by the potentiodynamic polarization was utilized to evaluate the inhibitor’s effectiveness. Optical emission spectroscopy (OES) was implemented to determine the percentage of elements in mild steel. Based on the FTIR results, C=O, -OH, C=C, benzene, and C-O are accountable for the inhibitor to donate its lone pair of an electron to the 3-d orbital of iron metal. Increasing the inhibitor concentration decreases the capacitive double layer to elevate the inhibitor resistance. The higher inhibitor resistance of 29.33 Ω cm-1 increases as the concentration increases due to the depression of Cdl 420.16 µF cm2 at 10 ml inhibitor solution. Parallelly, it increases the inhibition efficiency at 65.58 %, slightly lower than the PP measurement of nearly 88 %. The higher value of adsorption/desorption constant, Kads, at 2.9 L mol-1 shows the strength of the inhibitor, which lowers the value of Gibbs free energy (ΔGads). The Saga inhibitor is considered a chemisorption inhibitor ΔGads –36.87 kJ/mol. The value demonstrates the formation of dative covalent bonding, which promotes the transferred electron from the inhibitor to the substrate. On the other hand, the Saga inhibitor abides by the Langmuir adsorption isotherm as the R2 value is 0.99.

Salicylaldehydediol Grafted onto Chitosan: Characterization and Their Film Properties

The concentrations of linker group effect different physicochemical features of the biopolymer, including thermal stability, shape, swelling, and water solubility. Herein, three novel chitosan (CH) based films (CHSD1-3) have been prepared by a facile method for their film characteristics. Thus, amphiphilic salicylaldehydediol (SD) was synthesized from hydrophilic glycidol and salicylaldehyde in high yield and regioselectivity. CHSD1-3 films were prepared by the imine condensation reaction of polymeric chitosan backbone and various ratios of SD linker. The reaction takes place with high conversation and amazingly mechanically resistant thickness films without using any plasticizer that exhibits low water solubility and low swelling ratios at pH > 3, which can be suggested as thin layer protecting systems for medical devices. Chitosan-salicylaldehydediol biopolymer films were characterized by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) methods. The FT-IR, DSC, and XRD results show a clear linkage of the SD group to the chitosan backbone, high thermal stability of the films, and a change in the original nature of chitosan, respectively. Scanning Electron Microscopy (SEM) observations have also supported the successful grafting of the SD group onto the chitosan.

Morphological and Thermal Properties of Polystyrene/Poly (Vinyl Chloride) Blends

The present study investigated the morphological and thermal properties of polystyrene and polyvinyl chlorides blends (PS/PVC). The PS and PVC mixed by the solution casting by using cyclohexanone the ratios presented are 100/0,80/20,50/50,20/80 and 0/100 according to the weight of PS/PVC. Where the mixture formation is confirmed by Fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) respectively. The spectral FT-IR results showed that the blend of PS/PVC did not have molecular reactions. The thermal gravimetry was used to achieve the thermal stability of the polymer blends. Two degrees of glass transition temperature were observed for each mixture. The results of DSC supported the absence of miscibility in the blend. The distribution of the phases in the virgin and blends was studied through scanning electron microscopy (SEM).

Analysis of FTIR Spectra, Flavonoid Content and Anti-Tyrosinase Activity of Extracts and Lotion from Garcinia schomburgkiana by Multivariate Method

In this study, fourier transform infrared (FTIR) study, total flavonoid content and anti-tyrosinase activity of leaf, seed and flesh extracts of Garcinia schomburgkiana and lotion formulation from the extracts were carried out. Additionally, a relationship among FTIR spectra, total flavonoid content and anti-tyrosinase activity was analysed by partial least squares structural equation modelling (PLS-SEM) and principal component analysis (PCA) analysis. The result indicated that the highest total flavonoid content was found in leaf ethanol extract (214.00 ± 7.32 mg rutin equivalent per mg extract). For lotion samples, lotion containing leaf ethanol extract revealed the strongest level of total flavonoid content (5.51 ± 0.04 mg rutin equivalent per mL lotion). Moreover, anti-tyrosinase activity was observed in lotion containing the extracts (1/EC50 ranged from 0.0063 to 7.2334) higher than that of aqueous, ethanol and propanediol extracts (1/EC50 ranged from 0.0099 to 0.5319). The FTIR result confirmed the presence of various function groups in different parts of G. schomburgkiana and lotion samples, which involved the structure of flavonoids namely O-H stretch, C=O bending vibrations, unsaturation bonds, phenol or tertiary alcohol (O-H bend), C-O-H deformation and C-O stretching vibrations of aromatic ethers. The PLS-SEM analysis indicated a moderate positive relationship between the total flavonoid content and FTIR data, significantly (β = 0.502, t = 2.239, p-value < 0.05). The FTIR and subsequent PCA analysis could differentiate of aqueous, ethanol and propanediol extracts and lotion samples.
 HIGHLIGHTS
 
 FTIR data positively correlated with total flavonoid content
 Extract and lotion samples revealed total flavonoid content and anti-tyrosinase activity
 The PLS-SEM analysis showed significantly positive relationship between the total flavonoid content and FTIR data
 FTIR and subsequent PCA analysis differentiated extracts and lotions
 
 GRAPHICAL ABSTRACT

Enzyme activity inhibition properties of new cellulose nanocrystals from Citrus medica L. pericarp: A perspective of cholesterol lowering.

As a waste material, the amazing potential of cellulose nanocrystals (CNCs) isolated from Citrus medica L. pericarp in being a natural resource of lingo-cellulosic products has never been investigated before. In the present study, an alkaline pretreatment and a two-step bleaching procedure were applied to conduct the desired acid hydrolysis by the usage of 64% sulfuric acid at 50°C for 105 min. The extracted CNCs were distinguished through the means of transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), atomic force microscopy (AFM), Fourier-transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), zeta potential, and energy-dispersive X-ray spectroscopy (EDX). The elimination of peaks, which were accountable for the inducement of hemicelluloses and lignin, was confirmed by the FTIR results and were also validated by the outcomes of XRD that proved the gentle removal of non-cellulosic components. The morphology and size of CNCs were indicated through the FESEM and TEM results. In addition, the spherical forms of synthesized CNCs were observed with a diameter of 46 nm throughout the FESEM images, while displaying a value of 42.54nm as well due to TEM micrographs. The obtained zeta potential displayed a reasonable negative surface charge for CNCs. Furthermore, the cytotoxicity assessment of this product on fibroblast cells was performed to study their susceptibility for bio-medical and cosmetic industrial applications, which resulted in the lack of exhibiting any cytotoxic effects. In conformity to the outcomes of TEM and FESEM, the results of AFM revealed a fine dispersion and spherical form of cellulose nanoparticles. The interaction between HMG-CoA reductase and CNC was studied by the usage of multi-spectroscopic methods and enzyme kinetics to explore the binding mechanism of HMG-CoA reductase-CNC system. Reduced catalytic activity of the occurrence of changes in the secondary structure of HMG-CoA reductase was as a result of interacting with CNC causing a reduction in its catalytic activity.

Morphological, optical, structural, mechanical, and radiation-shielding properties of borosilicate glass–ceramic system

This study explores the morphological, optical, structural, mechanical, and radiation-shielding properties of borosilicate glass–ceramic samples modified with titanium oxide and various ratios of barium oxide. The morphology of the glass–ceramic system was investigated using scanning electron microscopy (SEM). The mechanical properties, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) were used to identify the fabricated sample structures. The optical properties were calculated to define the refractive index and band gap (Eg). The shielding properties were obtained by Monte Carlo simulation (MC) and compared with XCOM software data. Glass samples were converted to glass–ceramic samples at 800 °C for 6 h, and the GC25 and GC30 samples were converted to completely crystalline phases as illustrated by the XRD, FTIR, and Raman results, unlike the GC15 and GC20 samples. The XRD results showed the trigonal structure of BaB2TiO6 with the R-3 space group for the GC25 and GC30 samples and the tetragonal phase of TiO2 with the P42/mnm space group for the GC15 and GC20 samples. The sharp FTIR and Raman spectrum peaks affirm the crystal phase for G25 and G30 samples. The parent glass of the GC20 sample showed the highest mechanical moduli (Young's, bulk, shear, and longitudinal) and Poisson ratio. Concurrently, the addition of BaO instead of B2O3 caused a gradual reduction in the packing factor, dissociation energy, and microhardness. The Phy-X program was used to theoretically assess the shielding properties. The obtained results showed the highest compatibility between the Monte Carlo N-particle (MCNP) and XCOM software results, and the GC30 sample displayed the highest shielding properties due to adding BaO instead of B2O3. The crystalline phase and shielding features of the samples were improved by increasing the BaO ratio, indicating that the current samples are suitable for radiation-shielding applications.

Comparison of fast Fourier transform infrared spectroscopy biotyping with whole genome sequencing-based genotyping in common nosocomial pathogens

Early detection of bacterial transmission and outbreaks in hospitals is important because nosocomial infections can result in health complications and longer hospitalization. Current practice to detect outbreaks uses genotyping methods amplified fragment length polymorphism (AFLP) and whole genome sequencing (WGS), which are not suitable methods for real-time transmission screening of both susceptible and resistant bacteria. The aim was to assess the typing technique Fourier transform infrared (FTIR) spectroscopy as real-time screening method to discriminate large amounts of susceptible and resistant bacteria at strain level when there is no evident outbreak in comparison with the WGS reference. Isolates of past hospital outbreak strains of Acinetobacter baumannii/calcoaceticus complex (n = 25), Escherichia coli (n = 31), Enterococcus faecium (n = 22), Staphylococcus aureus (n = 37) and Pseudomonas aeruginosa (n = 30) were used for validation of FTIR. Subsequently, Enterococcus faecalis (n = 106) and Enterococcus faecium (n = 104) isolates from weekly routine screening samples when no potential outbreak was present were analysed. FTIR showed reproducibility and congruence of cluster composition with WGS for A. baumannii/calcoaceticus complex and E. faecium outbreak isolates. The FTIR results of E. faecalis and E. faecium isolates from routine samples showed reproducibility, but the congruence of cluster composition with WGS was low. For A. baumannii/calcoaceticus complex and E. faecium outbreak isolates, FTIR appears to be a discriminatory typing tool. However, our study shows the discriminatory power is too low to screen real-time for transmission of E. faecium and E. faecalis at patient wards based on isolates acquired in routine surveillance cultures when there is no clear suspicion of an ongoing outbreak.

High-Efficient Dust Trapping Performance of AES/Polyacrylamide Strengthen Foam Based on the Structure Stability and Dust Wettability.

The atmospheric dust has a great negative impact on the societal harmonious development that starves for an efficient dust suppressant. This paper proposes a novel AES/polyacrylamide strengthen foam (APSF) to improve the dust trapping effectiveness. The APSF structure property and dust suppression capacity are studied and evaluated through the molecular dynamics simulation and experimental tests. The results express that APSF exhibits the stronger structure stability, superior water retention, and slower drainage performance than the traditional water-based foam (WBF). APSF dynamic simulation is studied by the relative concentration, radial distribution function, head group orientation, and mean square displacement. Research shows that APSF introduces water to thicken the hydration layer. The interaction strength between water and surfactant head groups is enhanced by 22.62 and 31.37% in the first and second hydrated water shells. APSF improves the sodium fatty alcohol ether sulfate (AES) orientation and weakens the diffusion of water molecules, which favors the foam stability. APSF exerts a better wettability on the coal dust through the wet settlement and contact angle tests. The APSF liquid film thickness reduces to 58.05 from 64.80 μm that is 3.14 times of WBF according to the foam liquid film decay experiment. Fourier transform infrared (FTIR) spectroscopy analysis indicates that there is an evident reinforcement on the coal surface absorption peak intensity of hydroxyl- and oxygen-containing functional groups treated by APSF. FTIR results are further determined by energy-dispersion spectrum analysis.

Carrageenan xanthate as an environmental-friendly depressant in the flotation of Pb–Zn sulfide and its underlying mechanism

Carrageenan xanthate, a new reagent, produced by reacting carrageenan with NaOH and CS2, was used for the first time as a flotation separation depressant for sphalerite and galena. A variety of techniques were used to investigate the depressive effectiveness and mechanism of carrageenan xanthate, including micro-flotation tests, zeta potential, adsorption measurements, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopic (XPS) analysis, and time of flight secondary ion mass spectrometry (ToF-SIMS). The flotation results demonstrated that galena could be effectively separated from sphalerite by using 40 mg/L carrageenan xanthate as a depressant. Studies of zeta potential and adsorption revealed that carrageenan xanthate adsorbed on both mineral surfaces, however, the adsorption on the galena surface was less than that on sphalerite, and may have been replaced by xanthate. The FTIR and XPS results confirmed that carrageenan xanthate formed new chemical bonds by adsorbing on the surface of sphalerite. According to the surface analysis of high-precision ToF-SIMS, –CSS– in the structure of carrageenan xanthate can interact with active zinc atoms to adsorb onto the surface of sphalerite.

Effective Absorption Mechanism of SO2 and NO2 in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents.

Simultaneous capture of SO2 and NOx from flue gas is critical for coal-fired power generation. In this study, environmentally friendly and high-performance deep eutectic solvents based on ethylene glycol and ammonium bromide were designed to capture SO2 and NO2 simultaneously. The SO2 and NO2 absorption performances and absorption mechanisms were systematically investigated by 1H NMR and Fourier transform infrared (FT-IR) spectroscopy in combination with ab initio calculations using Gaussian software. The results showed that EG-TBAB DESs can absorb low concentrations of SO2 and NO2 from the flue gas simultaneously at low temperatures (≤50 °C). 1H NMR, FT-IR, and simulation results indicate that SO2 and NO2 are absorbed by forming EG-TBAB-SO2–NO2 complexes, Br– is the main active site for NO2 absorption, and NO2 is more active in an EG-TBAB-NO2–SO2 complex than SO2. EG-TBAB DESs exhibit outstanding regeneration capability, and absorption capacities remain unchanged after five absorption–desorption cycles. The fundamental understanding of simultaneous capture of SO2 and NO2 from this study enables DES structures to be rationally designed for efficient and low-cost desulfurization and denitrification reagents.

ENHANCEMENT OF SOLUBILITY OF POORLY SOLUBLE DRUG LANSOPRAZOLE

Objective: To improve the solubility of lansoprazole with solid dispersion (SD) method by using hydrophilic polymer PEG 6000, PEG 15000 and amphiphilic polymer solupus. Methods: Solid dispersions of lansoprazole were prepared with polymers PEG 6000, PEG 15000 and amphiphilic polymer soluplus, using three methods of preparation–1) solvent melting 2) solvent evaporation and 3) microwave heating method along with different drug: carrier ratios. Performance of the prepared formulations were evaluated for solubility, fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC) parameters. Results: All SDs showed enhancement in solubility of lansoprazole. Solubility and also carrier concentration showed a positive effect on solubility. The lansoprazole-soluplus solid dispersion 1:3 in concentration showed enhanced aqueous solubility when formulated with a solvent melting procedure. Conclusion: The studies indicated that PEG 6000, PEG 15000 and Soluplus inhibite crystallization of lansoprazole, subsequently form amorphous state in solid dispersion, which is, confirmed via FTIR and DSC results of lansoprazole solid dispersion.

Changes on the conformational and functional properties of soybean protein isolate induced by quercetin.

The conformational changes and functional properties of SPI induced by quercetin was investigated via fourier transform infrared (FTIR) spectroscopy, fluorescence spectroscopy, circular dichroism (CD) spectroscopy and molecular docking. A decrease in the fluorescence intensity and a blue shift in the maximum wavelength were observed due to the binding process with fluorescent residues. The analysis of Stern-Volmer equation showed that the fluorescence quenching induced by quercetin took the form of static quenching, and the binding stoichiometry between SPI and quercetin was 1:1. The values of ΔH and ΔS were both positive illustrating that hydrophobic interaction was the primary binding force between quercetin and SPI. Results of FTIR and CD indicated that the binding with quercetin changed the secondary structure of SPI, resulting in a partially unfolded and more flexible structure. SDS-PAGE confirmed there was no covalent interaction between the two constituents. Molecular docking demonstrated that there were stable configurations and high matching degrees in both 11S and 7S proteins with quercetin via hydrogen bonds and hydrophobic interactions. Meanwhile, modification by quercetin enhanced the foaming and emulsifying capacities of SPI. These findings might provide theory reference for elucidation the mechanism of polyphenols-proteins interaction and development of related food additive products in future.

Adsorption of nitrate from interflow by the Mg/Fe calcined layered double hydroxides.

Nitrate loss in interflow caused serious nitrate pollution of neighboring water bodies in the purple soil region of China's Sichuan Province. In this study, Mg/Fe(Al)-calcined layered double hydroxides (Mg/Fe(Al)-CLDHs) with varied Mg/Fe(Al) ratios were synthesized for nitrate removal from interflow, and 3:1 Mg/Fe CLDH exhibited the best adsorption performance. The effects of initial pH, adsorbent dosage and co-existing anions on the adsorption performance were investigated by batch experiments. The best-fitting kinetic and isothermal models for nitrate adsorption were the pseudo-second-order model and Freundlich model, respectively, indicating that the adsorption process was a physical-chemical multilayer process. The maximum adsorption capacity of nitrate was 73.36 mg/g, which was higher than that of many other commonly used adsorbents. The adsorbents were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) techniques, and the XRD and FT-IR results revealed that the adsorption mechanism involved original layered structure reconstruction and ion-exchange interaction. Under the coexistence of SO42- and Cl-, 75.63% nitrate in interflow could be removed after 6 h of adsorption. Overall, the synthesized Mg/Fe CLDH is an effective and low-cost nitrate adsorbent for in-situ nitrate removal.

Biodegradation of Gramineous Lignocellulose by Locusta migratoria manilensis (Orthoptera: Acridoidea)

Exploring an efficient and green pretreatment method is an important prerequisite for the development of biorefinery. It is well known that locusts can degrade gramineous lignocellulose efficiently. Locusts can be used as a potential resource for studying plant cell wall degradation, but there are few relative studies about locusts so far. Herein, some new discoveries were revealed about elucidating the process of biodegradation of gramineous lignocellulose in Locusta migratoria manilensis. The enzyme activity related to lignocellulose degradation and the content of cellulose, hemicellulose, and lignin in the different gut segments of locusts fed corn leaves were measured in this study. A series of characterization analyses were conducted on corn leaves and locust feces, which included field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction pattern (XRD), and thermogravimetric (TG) analysis. These results showed that the highest activities of carboxymethyl cellulase (CMCase), filter paper cellulase (FPA), and xylanase were obtained in the foregut of locusts, which strongly indicated that the foregut was the main lignocellulose degradation segment in locusts; furthermore, the majority of nutritional components were absorbed in the midgut of locusts. The activity of CMCase was significantly higher than that of xylanase, and manganese peroxidase (MnPase) activity was lowest, which might be due to the basic nutrition of locusts being cellulose and hemicellulose and not lignin based on the results of FE-SEM, FTIR, XRD, and TG analysis. Overall, these results provided a valuable insight into lignocellulosic degradation mechanisms for understanding gramineous plant cell wall deconstruction and recalcitrance in locusts, which could be useful in the development of new enzymatic pretreatment processes mimicking the locust digestive system for the biochemical conversion of lignocellulosic biomass to fuels and chemicals.