Fourier Transform Infrared Microscopy Research Articles

Fabrication of Antimicrobial Hydrogel Using Biodegradable Blended Materials for Skin Applications

Biodegradable polymers are very useful polymers in biomedical applications. In this research, several hydrogels were fabricated by using two polymers, Polyvinyl alcohol (PVA) and Chitosan (Chs) by the solvent casting method in order to use them for skin applications. Several tests were carried out on these membranes such as Agar diffusion method to examine their antimicrobial activities, Fourier transform infrared microscopy (FTIR) test to study the differences in their chemical structures. Uniaxial tensile test was performed to examine the mechanical characteristics of these membranes. In addition, the wettability test was used to investigate the hydrophobicity or hydrophilicity of the surfaces. The results showed that all membranes are hydrophilic, of which the contact angles are less than 90°. The membrane manufactured from 75:25 Chs-PVA is more hydrophobic (contact angle is 74°) than other membranes made of 50:50 Chs-PVA and 25:75 Chs-PVA as the contact angles were 59° and 61°, respectively. The tensile test results indicate that the membrane fabricated of the PVA and the membrane that was fabricated by 75% Chs and 25% PVA has the highest tensile strength of 17.9 MPa, 16.2 MPa and Young^’ s Modulus of 181.2 MPa and 7.18 MPa, respectively. The highest strain at break was observed by the membrane of 25:75 Chs-PVA which equals to 24.67%. Chitosan membranes showed inhibition zones of about 2.99 cm and 2.75 cm in length, and 75:25 Chs-PVA membranes showed 5.1 and 5.91 cm in length for E.coli. To sum up, this copolymer is considered as promising hydrogel for skin applications such as wound dressing.

Formulation and optimization of electrospun nanofiber films for ultrafast delivery of domperidone: In vitro and in-vivo characterization

Nanotechnology has significantly transformed drug delivery approaches by providing precise control of drug release kinetics and enhancing therapeutic effectiveness. Electrospun nanofiber films have unique features, including a significant surface-to-volume ratio and substantial porosity, resulting in enhanced patient adherence. The study was aimed at developing electrospun nanofiber films of domperidone for ultrafast release using polyvinyl alcohol (PVA). The nanofibers were prepared by electrospinning method and optimized using 32 factorial design. Electrospinning process parameters like feed rate, applied electric voltage, and tip-to-collector distance were optimized. The prepared nanofiber film was characterized using scanning electron microscopy, differential scanning calorimetry (DSC), Fourier transform infrared microscopy (FTIR), X ray diffraction (XRD), in-vitro diffusion, and permeation studies. The resultant domperidone-loaded nanofibers (diameters 280–565 nm) exhibited a uniform and highly porous structure. With an increase in applied voltage from 11 to 13 kV, entrapment efficiency increased, and fiber diameter decreased. DSC and XRD results confirmed the amorphous nature of the domperidone. The FTIR study confirmed the compatibility between domperidone and PVA. The wetting and disintegration times of nanofibers were 8 and 4 s, respectively. Due to their nanosize, small particles with an increased surface area resulted in improved drug delivery through nanofibers (93.36% release within 10 min). The nanofiber film had a higher Cmax (398.8 ng/mL) and AUC (2078.593 ± 17.71 ng/mL.h) than the commercial tablet formulation (186.6 ng/mL and 1875.619 ± 10.38). Thus, domperidone nanofibers would be a promising approach for enhancing therapeutic and biopharmaceutical properties by providing ultra-fast delivery.

Tracing the antioxidant effect of vitamin E on ultra-high molecular weight polyethylene

The antioxidant effect of vitamin E on ultra-high molecular weight polyethylene (UHMWPE) during radiation oxidation and post-irradiation oxidation process was investigated using electron paramagnetic resonance spectroscopy (EPR) and fourier transform infrared microscopy (FTIR). EPR results showed that the free radical concentration of UHMWPE induced by γ-rays irradiation decreased with increasing vitamin E content both in air and nitrogen atmosphere. FTIR results indicated that the irradiated samples underwent a continuous oxidation reaction, and the higher the vitamin E content, the lower the oxidation reaction. However, radiation oxidation also occurred inevitably to the vitamin E-stabilized UHMWPE indicating vitamin E could only partially prevent oxidation. Further investigation suggested that ozone can rapidly oxidize the vitamin E-stabilized UHMWPE, that is, vitamin E cannot prevent ozone from oxidizing UHMWPE. Then radiation oxidation schematic presentation of vitamin E-stabilized UHMWPE was described. This work would provide more comprehensive understanding on the radiation oxidation and post-irradiation oxidation of vitamin E-stabilized UHMWPE.

Poly(vinylidene fluoride) ultrafiltration membranes tailored with zirconium‐based MOF‐801 for water treatment applications

AbstractHighly hydrophilic and antifouling poly(vinylidene fluoride) (PVDF) ultrafiltration membranes are developed with excellent permeation using a zirconium‐based metal–organic framework (MOF‐801). MOF‐801 is synthesized by a solvothermal method using zirconium(IV) oxychloride octahydrate (ZrOCl2⋅8H2O) and fumaric acid. The chemical functionality of MOF‐801 is studied by Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) whereas surface morphology and elemental composition are probed by scanning electron microscopy (SEM)/energy‐dispersive X‐ray analysis (EDX). The PVDF/MOF‐801 membranes are characterized in terms of FTIR, XRD, FESEM/EDX and atomic force microscopy. The performance of the hybrid PVDF/MOF‐801 membranes in terms of pure water flux and antifouling ability is found to be improved compared with bare PVDF membranes. The wettability of the membranes is measured by water contact angle and found to be 76.7° for bare PVDF membrane, which decreases upon the addition of MOF‐801 to 55.1° due to the increase in surface hydrophilicity. A notable increase in roughness of 226.29 nm and a porosity of 67.91% is observed for the addition of 2 wt% MOF‐801 in PVDF membrane matrix. The flux recovery ratio of the hybrid membrane is increased from 66.4% to 89.6% and from 68.3% to 85.2% for bovine serum albumin (BSA) and humic acid (HA) separation, respectively. In addition, the reversible and irreversible fouling performance during the rejection of BSA (93%) and HA (88%) indicates the enhanced antifouling property of the PVDF/MOF‐801 membranes. A zone of inhibition test evidences the outstanding antibiofouling activity of the PVDF/MOF‐801 membranes against E. coli and S. aureus. Overall results demonstrated the suitability of hybrid PVDF/MOF‐801 membranes for water and wastewater treatment. © 2023 Society of Industrial Chemistry.

Hydrothermal as a synthesis method for characterization of structural, morphological and magnetic properties of Co–Al ferrite nanoparticles

This work provides a set of structural, morphological, and magnetic results for the CoFe2-xAlxO4 (x = 0.00, 0.25, 0.50, 0.75, 1.00 at %) ferrite nanoparticles synthesized by the hydrothermal route. X-ray diffraction analysis (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray Spectroscopy (EDAX), High Resolution Transmission Electron Microscopy (HRTEM), Selected Area Electron Diffraction (SAED) microscopy and Fourier-Transform Infrared Microscopy (FTIR) were used to characterize the structural and morphological features of the prepared magnetic nanoparticles. Rietveld refinement carried out by the Material Analyses Using Diffraction (MAUD) software confirmed the formation of a single-phase spinel structure with no trace of impurity phase. FESEM micrographs showed the appearance of the ferrite nanoparticles with a size distribution in agreement with the data reported by XRD. HRTEM analysis showed the formation of cubic-shaped nanoparticles with dimensions near to the data extracted from XRD. The formation of spinel structure was approved by the FTIR spectra. The magnetic measurements through VSM analysis showed that the incorporation of Al3+ cations into the cobalt ferrite lattices decreases the values of saturation magnetization from about 69 emu/g to near 26 emu/g, which was attributed to the none-magnetic nature of Al3+ cations. The values of the coercive field, on the other hand, indicate a fluctuating trend as a function of Al3+ doping. The coercivity behavior was mainly affected by cation distribution, the variation of anisotropy constant, and the size of crystallites. All the obtained data showed that the magnetic ferrite nanoparticles could be synthesized successfully through the hydrothermal method as a technique that has not been used previously to prepare Co–Al ferrite nanoparticles.

Effectiveness of chitosan nanohydrogel mediated encapsulation of EcR dsRNA against the whitefly, Bemisia tabaci Asia-I (Gennedius) (Hemiptera: Aleyordidae)

Bemisia tabaci is a global invasive pest causing substantial loss on several economically important crops and has developed a very high level of resistance to insecticides making current management practices ineffective. Thus, the novel pest management strategy like RNA interference (RNAi) has emerged as a potential molecular tool in the management of insect pests particularly B. tabaci. The present study investigated RNAi mediated silencing of the Ecdysone Receptor (EcR) gene in B. tabaci Asia-I using biodegradable Chitosan Nanoparticles (CNPs) hydrogel containing EcR dsRNA. The formation of nanohydrogel and dsRNA loading were characterized by gel retardation assay, scanning electron microscopy (SEM); transmission electron microscopy (TEM) and Fourier transform infrared microscopy (FTIR). The stability of CNPs/dsRNA was assessed by exposure to direct sunlight and UV light for different time periods. The CNPs/dsRNA exhibited increased stability over the untreated control and further confirmed by bioassay studies which yielded mortality over 80% and effectively down regulated the expression of the EcR gene as confirmed by qRT-PCR analysis. These investigations provide potential avenues for advancing innovative pest management strategies using biopolymer CNPs hydrogel, which can enhance the efficiency of dsRNA as a safe and targeted solution in the management of whiteflies.

Facile Extraction of Natural Hydroxyapatite (HA) from Biowaste and Its Characterizations

Natural Hydroxyapatite (HA) with chemical formula Ca10(PO4)6(OH)2 is a major mineral storage form of calcium and phosphorous in bone and it has been applied in many fields. In the present study, HA was extracted from biowaste; namely the buffalo bone by alkaline hydrolysis process followed by calcination at 900°C with holding time 6 hrs. in muffle furnace. The isolated material was analyzed by X-ray Diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR) and Field Emission Scanning Electron Microscopy (FESEM) etc. The SEM image suggested the isolated material had rod shaped and agglomerated. FTIR study indicated the phosphate and hydroxide were the major functional groups along with carbonate present in it. Further, XRD analysis inferred that the isolated material was only HA phased. The specific surface area of the isolated HA was determined by methylene blue adsorption method and it was found to be 141.12 m2 /g and pH point of zero charge (pHPZC) of the extracted biomaterial was determined to be 6.8 by pH the drift method. Thus the pure HA powder was synthesized by an environmentally friendly, cost effective method and may be applicable in many fields including waste water treatment and biomedicine etc.

AS1411aptamer conjugated liposomes for targeted delivery of arsenic trioxide in mouse xenograft model of melanoma cancer

Development of AS1411aptamer-conjugated liposomes for targeted delivery of arsenic trioxide is the primary goal of this study. AS1411aptamer was used as ligand to target nucleolin, which is highly expressed on the surface of melanoma cancer cells. The targeted liposomes were constructed by the thin film method, and arsenic trioxide was loaded as cobalt (II) hydrogen arsenite (CHA) to increase the loading efficiency and stability of the liposomes. The liposomal structure was characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and field emission scanning electron microscopy (FESEM). In addition, particle sizes and zeta potential of the CHA-loaded liposomes (CHAL) and aptamer-functionalized CHA-loaded liposomes (AP-CHAL) were determined. In vitro cytotoxicity of CHAL and AP-CHAL were evaluated using MTT assay in murine melanoma (B16) and mouse embryonic fibroblast (MEF) cell lines. The encapsulation efficiency of CHAL and AP-CHAL was reported as 60.2 ± 6.5% and 58.7 ± 4.2%, respectively. In vivo antitumor activity of CHAL and AP-CHAL in the B16 tumor-xenograft mouse model was dramatically observed. All mice of both groups survived until the end of treatment and showed body weight gain. The tumor protrusion completely disappeared in 50% of the mice in these groups. Furthermore, histopathology studies demonstrated that CHAL and AP-CHAL did not induce significant toxicity in healthy mice tissues. However, unlike the CHAL group, which showed an initial increase in tumor volume, a specific antitumor effect was observed in the AP-CHAL group from the beginning of treatment. The results showed that AP-CHAL can be used as an effective drug delivery system with high potential in the treatment of solid tumors.

Deciphering the role of fungus in degradation of polypropylene from hospital waste.

Health and environmental consequences are unavoidable when it comes to management of hospital waste (HW) disposables. In order to eradicate the HW, this study isolated a novel fungus SPF21 from a hospital dumping yard to degrade Polypropylene (PP). We measured the attributes of PP inoculated with fungus using mass loss, Fourier trans-form infrared (FTIR), contact angle (CA), and scanning electron microscopy (SEM). The weight of PP exposed to SPF21 was reduced by 25% in 90 days. The SEM images reveal that there are pores all over the sample surface; they alsocaused voids during the biodegradation of PP. FTIR analysis indicates that the spectra of treated mask pieces show the absence of peak at 1746cm-1 and the appearance of a new peak at 1643cm-1 . A period of 90-day exposure to the fungal isolate SPF21 reduced the CA of PP by 44.8% when compared to the nonexposed PP samples, suggesting that the surface of PP turned more hydrophilic after exposure. Moreover, our study on PP degradation by the fungus Ascotricha sinuosa SPF21 appears to be promising from the perspective of environmental, health, and economic hazards. Our results indicate that biodegradation greatly facilitates fungus deposition and changes PP film morphology and hydrophilicity.

Novel Bone Void Filling Cement Compositions Based on Shell Nacre and Siloxane Methacrylate Resin: Development and Characterization.

Shell nacre from Pinctada species has been extensively researched for managing bone defects. However, there is a gap in the research regarding using shell nacre powder as a cement with improved biological and physicochemical properties. To address this, bone void filling cement was formulated by incorporating shell nacre powder and an organically modified ceramic resin (ormocer). The shell nacre powder was specifically processed from the shells of Pinctada fucata and analysed using thermogravimetric analysis (TGA), X-ray diffraction spectroscopy, Fourier transform infrared (FTIR), and Raman spectroscopy, confirming the presence of organic constituents and inorganic aragonite. Trace element analysis confirmed the eligibility of shell nacre powder for biomedical applications. Next, the ormocer SNLSM2 was synthesized through a modified sol-gel method. FTIR, Raman, TGA, and transmission electron microscopy studies revealed the presence of a ladder-structured siloxane backbone and methacrylate side chain. To develop chemical curable composite shell nacre cement (SNC), different amounts of shell nacre (24%, 48%, and 72%) were added to the SNLSM2 resin, and the impact on the physicochemical properties of the cement was studied. Among the compositions, SNC 72 exhibited significantly lower linear polymerization shrinkage (0.4%) and higher compressive (>100 MPa) and flexural strength (>35 MPa). SNC 72 was radiopaque, and the exotherm generated during the cement curing was minimal. Cytotoxicity studies with L929 cells revealed the non-cytotoxic nature of the cement. Overall, the findings of this study prove that the shell nacre cement is a promising candidate for managing bone voids.

Preparation and evaluation of a functional effervescent powder based on inclusion complexes of orange oil and β-cyclodextrin derivatives

Flavoured functional effervescent powders are becoming increasingly popular by consumers due to their health benefits and easy dissolution. In present study, orange flavoured effervescent powders having functional properties were prepared. Orange oil (O) was blended with different essential oils (EOs) that have high antioxidant activity. The orange oil and the O-EOs blends were subjected to odour sensory evaluation, gas chromatography-mass spectrometry (GC-MS) analysis and evaluation of radical scavenging activity. Combinations of two water soluble β-cyclodextrin polymers, 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) and epichlorohydrin-β-cyclodextrin (EPI-β-CD), were prepared at different molar ratios (3:1 and 1:3, F1 and F2, respectively). The O-EOs blends that showed the highest antioxidant activities and best odour qualities were encapsulated with F1 and F2, separately. The orange flavoured inclusion complexes were prepared by freeze drying method. The particle sizes of the inclusion complex powders were in the nanoscale. Characterization of the inclusion complexes nanoparticles was performed by scanning electron microscopy (SEM), and fourier transform infrared microscopy (FT-IR). The results confirmed the successful formation of the inclusion complexes. However, inclusion complex of O-EOs (300 mg) blend with F1 (OF1cIC) showed the smallest particle size (113.90±15.90 nm), the more negative zeta potential (−27.10±1.27 mV), the highest encapsulation efficiency (95.51%) and best odour quality. Therefore, it was mixed with an effervescent powder having high acceptable characteristics. The orange flavoured effervescent powder showed superior flowability.

Mechanism of Insoluble Aggregate Formation in a Reconstituted Solution of Spray-Dried Protein Powder

BackgroundSpray-drying is considered a promising alternative drying method to lyophilization (freeze-drying) for therapeutic proteins. Particle counts in reconstituted solutions of dried solid dosage forms of biologic drug products are closely monitored to ensure product quality. We found that high levels of particles formed after reconstitution of protein powders that had been spray-dried under suboptimal conditions.MethodsVisible and subvisible particles were evaluated. Soluble proteins in solution before spray-drying and in the reconstituted solution of spray-dried powder were analyzed for their monomer content levels and melting temperatures. Insoluble particles were collected and analyzed by Fourier transform infrared microscopy (FTIR), and further analyzed with hydrogen-deuterium exchange (HDX).ResultsParticles observed after reconstitution were shown not to be undissolved excipients. FTIR confirmed their identity as proteinaceous in nature. These particles were therefore considered to be insoluble protein aggregates, and HDX was applied to investigate the mechanism underlying aggregate formation. Heavy-chain complementarity-determining region 1 (CDR-1) in the aggregates showed significant protection by HDX, suggesting CDR-1 was critical for aggregate formation. In contrast, various regions became more conformationally dynamic globally, suggesting the aggregates have lost protein structural integrity and partially unfolded after spray-drying.DiscussionThe spray-drying process could have disrupted the higher-order structure of proteins and exposed the hydrophobic residues in CDR-1 of the heavy chain, contributing to the formation of aggregate through hydrophobic interactions upon reconstitution of spray-dried powder. These results can contribute to efforts to design spray-dry resilient protein constructs and improve the robustness of the spray-drying process.

Nickel Supported on MIL-96(Al) as an Efficient Catalyst for Biodiesel and Green Diesel Production from Crude Palm Oil
 

heterogeneous catalyst in the form of metal-organic frameworks (MOFs), namely Material of Institute Lavoisier-96(Al), which is called MIL-96(Al), was employed for the production of biodiesel and green diesel. The synthesis of MIL-96(Al) was conducted via a hydrothermal method at 210 °C for 4 hours with dimethylformamide (DMF) as an assisting agent. The Ni was loaded into MIL-96(Al) via incipient wetness impregnation method with variations 3, 5, and 10 wt.% to form Ni/MIL-96(Al). Based on X-Ray diffraction (XRD) analysis, the obtained material has good crystallinity with characteristic peaks observed at 2? = 5.8°; 7.8°, and 9.1°. Fourier Transform Infrared (FTIR) analysis demonstrated an essential shift from 1715 cm-1 to 1666 cm-1, indicating the coordination of the carboxylate group with Al3+ metal ions. Moreover, MIL-96(Al) is stable up to 390 °C according to the thermogravimetric analysis (TGA). Based on structural and morphological analysis (using XRD, FTIR, and Scanning Electron Microscope (SEM)), the loading of Ni into MIL-96(Al) does not change the basic structure of MIL-96(Al). However, the pore diameter of MIL-96(Al) decreased from 5.7 nm to 1.4 nm after the Ni was embedded in the structure. The largest surface area was obtained from 10% Ni/MIL-96(Al) (up to 595.5 m2/g). The catalytic test exhibits that 3% Ni/MIL-96(Al) could attain an optimum yield of up to 85.24% of biodiesel, while in the case of hydrodeoxygenation (HDO) reaction, the optimum catalyst shown by 10% Ni/MIL-96(Al) with conversion and selectivity of C16 up to 90.70% and 55.22%, respectively.

Initial stage degradation of GFRP bars based on functional group ratio change using FTIR in high temperature and alkaline solution

Although extensive research has been conducted on the use of glass fibre-reinforced polymer (GFRP) bars in concrete, one factor that hinders their widespread use in civil engineering is the lack of prediction of degradation properties in concrete for long-term applications. This paper presents the tensile strength (TS) retention and microstructure evolution of GFRP bars in high-temperature and alkaline solutions by Fourier transform infrared (FTIR) spectroscopy. The test results indicated that with TS retention above 70%, the main reason for the mechanical property loss was resin degradation. Significant chemical degradation of the rod surface, namely, the breaking of ester bonds and the formation of carboxylates, was observed by FTIR and scanning electron microscopy (SEM). However, when the TS retention was less than 70%, damage to the bars was induced by debonding of the resin/fibre and localized damage to the resin and fibres. Finally, the relationship between the functional group ratio change and TS retention of GFRP was established using FTIR, revealing a linear relationship and introducing a coefficient k for modification. This can provide a scientific basis for the subsequent method to predict the degree of mechanical property degradation of GFRP bars by FTIR monitoring of the functional group ratio change.

The applicability of Fourier transform infrared microspectroscopy for correction against matrix effects in X-ray fluorescence microimaging of tissues

X-ray fluorescence (XRF) and Fourier transform infrared (FTIR) microscopy techniques are now considered popular for rapid and label-free complementary spectrochemical analysis of chemical elements and molecular systems in biological specimens. The morphological heterogeneity but also the inhomogeneities associated with the thickness/density of biological samples demonstrate challenges for the quantitative XRF microimaging. Therefore, in the present work, we proposed for the first time the application of the total absorbance under the FTIR spectra as a mass surface correction procedure for two-dimensional (2D) XRF microimaging of tissues. We also evaluated the equivalence of the developed correction method based on total absorbance of FTIR spectra with the proposed approaches based on incoherent scattering of primary X-rays as well as on the membrane Si–Kα transmission signal, on the example of selected rat organ tissues. Thin cryo-sections taken from various organs of Wistar rats were deposited on silicon nitride membranes (Si3N4). The FTIR microscopy studies were performed to collect infrared absorption spectra, used then for the determination of total absorbance values in the selected areas of tissue samples. In turn, hard X-ray imaging based on synchrotron radiation allowed the determination of characteristic radiation intensities of the elements detectable from the tissue, as well as the characteristic radiation of the membrane Si and incoherently scattered X-ray photons (Compton scattering). The latter served as correction factors for the surface mass of the sample alongside the FTIR total absorbance. The qualitative and quantitative analyses showed a high agreement between the results of elemental surface mass correction using total absorbance under FTIR spectra of tissues with those obtained using surface mass correction factors determined directly from XRF spectra. Therefore, the proposed procedure is a good alternative in cases where the surface mass effect of the sample cannot be eliminated based on the information provided directly by the XRF spectrum, as in the case of using polymer films as sample support. We have also proposed a procedure for synchronizing SRXRF and FTIR images, not limited to visual inspection of imaging/mapping data, but also enabling quantitative analysis. We found that the total absorbance determined from FTIR spectra can be successfully used as a correction factor for eliminating the surface mass effect in XRF microimaging of thin freeze-fried tissues and therefore to obtain the surface mass-independent elemental quantities. The proposed approach for 2D-FTIR-XRF analysis can also be a powerful and versatile tool for fostering a correlation and co-localization analysis to search for common distribution patterns between molecular arrangements and chemical elements.

Comprehensive analysis of properties of green diesel enhanced by fatty acid methyl esters.

This study systematically investigates the lubricating properties of bio-hydrogenated diesel (BHD), a synthetic diesel produced through biomass hydrogenation of vegetable oil. Despite having similar chemical properties to petroleum diesel, BHD has poor lubricating properties due to the removal of sulfur and oxygenated compounds during the hydrogenation process, which could damage the engine. To address this issue, fatty acid methyl esters (FAME) was added as an additive to BHD to enhance its fuel and lubricating properties. FAME is a polar molecule with good lubricating properties that adsorb on the surface to protect against wear. The study found that adding as little as 5% FAME significantly improved the lubricating properties of BHD. The wear scar diameter (WSD) decreased from 609 μm to 249 μm, and the average film was 94% with an average coefficient of friction of 0.138 by only 5% FAME addition investigated by High Frequency Reciprocating Rig with ISO 12156-1: 2018. This shows that blending FAME with BHD could reduce engine wear and improve its lubricating properties. Disc samples were analyzed using a Scanning Electron Microscope (SEM), OLS5100 3D laser microscopy, and Fourier Transform Infrared Microscopy (FTIR) to examine the worn surface both physically and chemically. An increase in the percentage of FAME addition to BHD resulted in a smoother worn surface, exhibiting reduced delamination and debris compared to pure BHD. This effect was attributed to the protective film formed by FAME. The study highlights the potential of FAME as an additive to enhance the lubricating properties of BHD and reduce engine wear.

Preparation of Composite Films of Sodium Alginate-Based Extracted from Seaweeds Macrocystis pyrifera and Lessonia trabeculata Loaded with Aminoethoxyvinylglycine

Composite films are an alternative in the replacement of synthetic polymers. These films can be prepared from polysaccharides and used to store various drugs to be applied in different areas. In addition, aminoethoxyvinylglycine (AVG) is an ethylene inhibitor that prolongs shelf life of food. For this reason, this research aimed to take advantage of the brown algae Macrocystis pyrifera and Lessonia trabeculata to extract sodium alginate and produce films composed of sodium alginate/ kappa-carrageenan/iota-carrageenan, which were plasticized with glycerol and polyethylene glycol 400 and loaded with aminoethoxyvinylglycine. The extracted sodium alginate was characterized by 1 H and 13C nuclear magnetic resonance (NMR), size exclusion chromatography coupled with multi-angle light scattering (SEC-MALS), thermogravimetry (TG/DTG), Fourier transform infrared (FTIR), and X-ray diffraction (XRD); and the composite films were characterized by FTIR, XRD, TG/DTG, and scanning electron microscopy (SEM). Then, the drug release kinetics were investigated using Higuchi and Korsmeyer-Peppas kinetic models. The extracted alginates obtained were of low molecular weight, and the films showed desirable properties for AVG release. Furthermore, drug release profiles revealed that AVG release is governed by Fick’s Law, and this is favored at low temperatures. In summary, sodium alginate allows the preparation of composite films, which can replace synthetic polymers to be used in the loading and releasing of drugs.

Effect of Vacuum Heat Treatment on Larch Earlywood and Latewood Cell Wall Properties

The aim of this study was to evaluate the hygroscopicity and nanomechanics of earlywood (EW) and latewood (LW) larch after thermal modification under vacuum conditions. Wood samples were heat-treated in a vacuum atmosphere at 180–220 °C for 6 h, then their cell wall properties were observed using dynamic water vapor sorption (DVS), imaging Fourier-transform infrared (FTIR) microscopy, and nanoindentation. The results showed that the vacuum heat treatment reduced the hygroscopicity of EW and LW and increased hysteresis between the adsorption and desorption branches of the isotherm. Compared with EW, the treatment temperature had a more pronounced influence on the hygroscopicity of LW. The Hailwood-Horrobin model was found to accurately fit the experimental data. Imaging FTIR microscopy revealed degradation of hemicellulose, cross-linking, condensation reactions, and redistribution of lignin in the cell wall. The elastic modulus for the heat-treated EW and LW cell walls increased at first and then decreased as the treatment temperature increased; the increase in LW was more intense than that in EW. Cell wall hardness also markedly increased after heat treatment. Our analysis suggests that vacuum heat treatment decreases hygroscopicity and alters the chemical composition distribution of cell walls, thus improving wood cell wall mechanics.

AS1411aptamer conjugated liposomes for targeted delivery of arsenic trioxide in mouse xenograft model of melanoma cancer

Development and characterizing of AS1411aptamer conjugated liposomes for targeted delivery of arsenic trioxide is the primary goal of this study to increase the drug safety and efficacy in the treatment of solid tumors. The targeted liposomes were constructed by the thin film method, and arsenic trioxide was loaded as cobalt (II) hydrogen arsenite (CHA). The liposomal structure was examined by Fourier Transform Infra-red Spectroscopy and field emission scanning electron microscopy. In addition, particle sizes and zeta potential of the CHA-loaded liposomes (CHAL) and aptamer-functionalized CHA-loaded liposomes (AP-CHAL) were determined. An atomic absorption spectrometer was used to quantify the encapsulation efficiency and in vitro drug release. In vitro cytotoxicity of CHAL and AP-CHAL were evaluated using MTT assay in Murine melanoma (B16) and Mouse Embryonic Fibroblast cell lines. The encapsulation efficiency of CHAL and AP-CHAL was reported as 60.2 ± 6.5 % and 58.7 ± 4.2 %, respectively. The enhanced cellular uptake of aptamer-conjugated liposomes was displayed by Fluorescence imaging. In vivo antitumor activity of CHAL and AP-CHAL in the B16 tumor-xenograft mouse model was dramatically observed. All mice in the CHAL group survived to the end of treatment and showed body weight gain. However, the distinct antitumor effect was observed in the AP-CHAL-treated group, and the tumor protrusion completely disappeared in 50 % of the mice. The inhibition rate of tumor growth of CHAL and AP-CHAL was 92.73 % and 97.67 %, respectively. Furthermore, histopathology studies demonstrated that CHAL and AP-CHAL did not induce significant toxicity in mice tissues. AP-CHAL can be used as an effective drug delivery system with high potential in treating solid tumors.

Synthesis and evaluation of amino acid modified polyepoxysuccinic acid as inhibitor of calcium carbonate scale

Abstract Amino acid (AA) was used as a green grafting agent to functionalize polyepoxysuccinic acid (PESA), and three AA-modified PESA (AA-PESA) CaCO3 scale inhibitors were obtained to change the structural singleness of PESA and further improve its comprehensive properties. The structures of AA-PESA were characterized by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance hydrogen (1HNMR) spectroscopy. The molecular weights of AA-PESA were analyzed by gel permeation chromatography (GPC). The synthesis technology of AA-PESA was optimized by single-factor and orthogonal experiments. The CaCO3 scale inhibition performance of AA-PESA was studied by the static scale-inhibition method, and the scale inhibition mechanism was analyzed. Results showed that AA-PESAs had the same synthesis process: n(PESA):n(AA) = 1:0.625, reaction temperature of 95 °C, and reaction time of 2 h. In the water system with pH 7.0–8.5, agent concentration of 8–10 mg/L, action period of 10–14 h, ambient temperature <80 °C, and ρ(Ca2+) < 250 mg/L, the inhibition rate of the three AA-PESAs on CaCO3 could reach 100%, and GIN was preferred for the graft modification of PESA. FTIR, X-ray diffraction (XRD), and scanning electron microscopy (SEM) results showed that the addition of AA-PESA could control the nucleation sites of CaCO3 crystals, had important influence on the growth of calcite (104) crystal planes, and had a good inhibitory effect on the CaCO3 scale.