FTIR Peaks Research Articles

CNT-TiO2 nanocomposite thin films enhanced photocatalytic degradation of methylene blue

CNT-TiO2 nanocomposite thin films were deposited on quartz glass substrates using sol-gel spin coating and tested the photocatalytic degradation of methylene blue (MB) under the irradiation of the solar spectrum. The absence of any sharp peak in the XRD pattern confirmed the amorphous nature of the films. The bandgap, Eg, decreased from 3.94 to 3.70 eV as the concentration of CNT increased from 0 to 3 mg. The FTIR peak detected at 1040 cm−1 indicated the vibrations of the chemical bond Ti–O–C. The photocatalytic degradation of MB rose up to 83% (CNT@2 mg) owing to charge carrier separation between TiO2 and CNT.

Microplastics weaken the exoskeletal mechanical properties of Pacific whiteleg shrimp Litopenaeus vannamei

The ubiquitous presence of microplastics (MPs) in aquatic environments poses a significant threat to crustaceans. Although exoskeleton quality is critical for crustacean survival, the impact of MPs on crustacean exoskeletons remains elusive. Our study represents a pioneering effort to characterize the effects of MPs exposure on crustacean exoskeletons. In this study, the mechanical properties of whiteleg shrimp Litopenaeus vannamei exoskeletons were analyzed after exposure to environmentally realistic levels of MPs. Nanoindentation data demonstrated that MPs exposure significantly increased the hardness and modulus of both the carapace and abdominal segments of L. vannamei. Moreover, fractures and embedded MPs were detected on the exoskeleton surface using SEM-EDS analysis. Further analysis demonstrated that the degree of chitin acetylation (DA) in the shrimp exoskeleton, as indicated by FTIR peaks, was reduced by MPs exposure. In addition, exposure to MPs significantly inhibited the muscle Ca2+-ATPase activity and hemolymph calcium levels. Transcriptome and metabolome analyses revealed that the expression levels of genes encoding key enzymes and metabolites in the chitin biosynthetic pathway were significantly affected by MPs exposure. In conclusion, MPs at environmentally relevant concentrations may affect the exoskeletal mechanical properties of L. vannamei through a comprehensive mechanism involving the disruption of the crystalline structure of chitin, assimilation into the exoskeleton, and dysregulation of exoskeleton biosynthesis-related pathways.

Green and environmentally friendly synthesis of silver nanoparticles with antibacterial properties from some medicinal plants

Recently there have been a variety of methods to synthesize silver nanoparticles, among which the biosynthesis method is more noticeable due to features like being eco-friendly, simple, and cost-efficient. The present study aims for the green synthesis of silver nanoparticles from the extract of the three plants A. wilhelmsi, M. chamomilla, and C. longa; moreover, it pledges to measure the antibacterial activity against some variants causing a skin rash. The morphology and size of the synthesized silver nanoparticles were evaluated by UV.vis, XRD, SEM, and FTIR analyses. Then results showed a color alteration from light yellow to dark brown and the formation of silver nanoparticles. The absorption peak with the wavelength of approximately 450 nm resulting from the Spectrophotometry analysis confirmed the synthesis of silver nanoparticles. The presence of strong and wide peaks in FTIR indicated the presence of OH groups. The SEM results showed that most synthesized nanoparticles had a spherical angular structure and their size was about 10 to 20 nm. The highest inhibition power was demonstrated by silver nanoparticles synthesized from the extract combined from all three species against Gram-positive bacteria Staphylococcus aureus and Staphylococcus epidermidis (23 mm) which had a performance far more powerful than the extract. Thus, it can be understood that the nanoparticles synthesized from these three species can act as potential environment-friendly alternatives to inhibit some variations causing skin disorders; an issue that calls for further clinical studies.

Characterization of Microcrystalline Cellulose Isolated from Paper Sludge

The large amount of paper sludge generated from wastepaper industries emphasizes the importance of developing green waste management. The study aimed to characterize microcrystalline cellulose from paper sludge using different acid concentrations. The properties of chemical composition, morphological, thermal, reflectance, and crystallinity index were accessed. The disappearance of peaks in FTIR was related to the removal of amorphous structure. SEM confirmed the reduction in diameter with the decomposed temperature of 266°C. 3.0 M reflects the highest UVB at 28% and UVA at 39% due to the highest crystallinity index of 31%, which is possible for reinforcement application in film packaging.

Characterisation and energy storage performance of 3D printed-photocurable resin/microencapsulated phase change material composite

The 3D fabrication of microencapsulated phase change material (MEPCM) doped resin polymer composites enables the creation of complex shapes and customized designs, opening doors for many applications in fields. This investigation fabricated a range of resin/MEPCM (20 %, 30 %, and 40 % by volume) composites using a mechanical mixing technique. This study investigates how the addition of MEPCM impacts resin matrix composite's mechanical strength, latent heat storage characteristics, and ability to regulate temperature effectively. With a 40 % MEPCM additive ratio, a pure resin porosity value of approximately 0.4 % increased to around 17 %. Thanks to the production of homogeneously dispersed MEPCM added resins with production with stereolithography (SLA), 40 % MEPCM additive enabled characteristic FTIR peaks of both MEPCM and resin to appear and, melting and solidification enthalpy values reached 87.15 j/g and 86.25 j/g, respectively. MEPCM addition enhanced the thermoregulatory properties of resin by absorbing or releasing heat during temperature fluctuations. On hotter days, 8 mm-thick composites create temperature differences exceeding 11 °C, while this difference exceeds 6 °C in the room center case. The produced 3D printed MEPCM/resin composite can be a potential material to effectively regulate the temperature of electronic devices, food packets, building materials, and electronic devices and automotive components.

In vitro analysis of tantalum-containing mesoporous bioactive glass fibres for haemostasis

Haemorrhage is the leading cause of battlefield deaths and second most common cause for civilian mortality worldwide. Biomaterials-based haemostatic agents are used to aid in bleeding stoppage; mesoporous bioactive glasses (MBGs) are candidates for haemostasis. Previously made Tantalum-containing MBG (Ta-MBG) powders’ compositions were fabricated as electrospun fibres for haemostatic applications in the present study. The fibres were fabricated to address the challenges associated with the powder form: difficult to compress without gauze, getting washed away in profuse bleeding, generating dust in the surgical environment, and forming thick callus-difficult to remove for surgeons and painful for patients. Ta-MBGs were based on (80-x)SiO2-15CaO-5P2O5-xTa2O5 mol% compositions with x = 0 (0Ta), 0.5 (0.5Ta), 1 (1Ta), and 5 (5Ta) mol%. The present study details the fibres’ in vitro analyses, elucidating their cytotoxic effects, and haemostatic capabilities and relating these observations to fibre chemistry and previously fabricated powders of the same glasses. As expected, when Ta addition is increased at the expense of silica, a new FTIR peak (non-bridging oxygen-silicon, Si-NBO) develops and Si-O-Si peaks become wider. Compared to 0Ta and 1Ta fibres, 0.5Ta show Si-O peaks with reduced intensity. The fibres had a weaker intensity of Si-NBO peaks and release fewer ions than powders. A reduced ion profile provides fibres with a stable matrix for clot formation. The ion release profile for 1Ta and 5Ta fibres was significantly lower than 0Ta and 0.5Ta fibres. Ta-MBGs were not found to be cytotoxic to primary rat fibroblasts using a methyl thiazolyl tetrazolium (MTT) assay. Furthermore, a modified activated partial thromboplastin time assay analysing the fibrin absorbance showed that the absorption increases from physiological clotting < 0Ta < 0.5Ta < 5Ta < commercial haemostat, Surgical SNoWTM, Ethicon, USA < 1Ta. Higher absorption signifies a stronger clot. It is concluded that Ta-MBG fibres can provide stable matrix for clot formation and 1Ta can potentially enhance clotting best among other Ta-MBGs.

SYNTHESIS OF ACRYLIC ACID-BASED ZINC OXIDE NANOCOMPOSITE WITH ANTICANCER APPLICATION

The zinc oxide nanoparticles were synthesized using Brassia actinophylla (B. actinophylla)flower extract. The ZnO nanoparticles were introduced into TDA hydrogel (T-tartaric acid, D-diethylene glycol, A-acrylic acid) to form the TDA-ZnO nanocomposite. The UV-peak was observed at 280 nm and the FT-IR peak was obtained at 685 cm1confirming the presence of nanoparticles in the hydrogel. The nanoparticle's size was confirmed by TEM and SEM analysis. The anticancer activity of polymer nanocomposites was performed against the A549 lung cancer cell line and the results have been recorded and compared.

Synthesis, characterization, and application of N-CNT/1-(2-Hydroxyethyl)-3-methylimidazolium dicyanamide as a green nanocatalyst for the sulfur removal from light oils

Adsorptive desulfurization of light fuels is sustainable due to its ambient operation and reusability of exhausted adsorbents. In this study, 1-(2-hydroxyethyl)-3-methylimidazolium dicyanamide [HEMIM][DCA] IL was synthesized and utilized to modify N-doped carbon nanotubes (CNTs) to produce N-CNT/[HEMIM][DCA] as a green hybrid adsorbent. The adsorbent was characterized using XRD, FE-SEM, FTIR, BET, and TGA. It was indicated that the N-CNT treatment with [HEMIM][DCA] IL resulted in decreased crystallinity with the cubic and rod-shaped morphology and harsh surfaces and curved edges. The absence of shifts or variations in FTIR peaks of starting materials and N-CNT/[HEMIM][DCA] suggested that neither component was affected by chemical interactions. The adsorption capacity of N-CNT and N-CNT/[HEMIM][DCA] was 54.3 mg/g and for 83.6 mg/g for 50 ppm BT, respectively. Saturated with BT, the adsorbent's performance was decreased at high BT concentrations. The adsorption isotherms provided an understanding of interactions of BT with sorbent surface which follows the Langmuir model for N-CNT/[HEMIM][DCA] and N-CNT. The kinetics of BT adsorption on N-CNT/[HEMIM][DCA] was fitted with second-order kinetic model with the decreased adsorption ratio over time due to pore saturation. 25 % reduction of the adsorption capacity was obtained after two recycling cycles of the adsorbent (62.5 mg/g). N-CNT/[HEMIM][DCA] showed good recyclability and potential as a promising BT adsorbent.

Natural Green Synthesis of Silver Nanoparticles using Leaf Extract of Guazuma Ulmifolia Lam and Analysis of its Antimicrobial Property

Abstract: In the field of life science, nanoparticles are one of the leading adverse technologies. Here, the particles are seen in nanometers of 1–100 nm. In small-size particles, many useful applications are seen in the fields of medicine, pharma, agriculture, and many more industry sectors. In the present study, Guazuma ulmifolia, a member of the Malvavceae family, was a test plant. In this study, silver nanoparticles were synthesised from plant extract. Characterization using SEM, XRD, FTIR, and UV spectra confirmed the presence of nanoparticles. Silver nanoparticle sizes were measured using SEM, and the sizes ranged from 132nm to 352 nm. The XRD size of silver nanoparticles calculated using Debye-Scherrer’s equation was found to be 15.31 nm. Four drop-down FT-IR peaks were observed, which are 3369.60, 2162.44, 1643.53, and 635.04. N-H and C-I bonds were observed, and UV-Vis nanoparticles synthesised showed maximum absorptions between 300 nm to 700 nm. The sharp bands of silver nitrate nanoparticles were around 535nm for fresh leaves. The antimicrobial activity of synthesised nanoparticles against bacterial test pathogens, viz., Escherichia coli, Salmonella typhi, Bacillus subtilis, and Staphylococcus aureus, showed significant antibacterial activity. The average percentage of inhibition of bacteria is 38.83%, 0%, 10%, and 18.5%. Antifungal activity was also observed against Aspergillus niger, Fusarium oxysporum, Penicillium atramentosum, Aspergillus flavus, and Alternaria solani. The average percentage of inhibition in fungi is 15.68%, 58.53%, 0%, 32%, and 22.2%.

Trans-Purification of spent carbide via pressure pot into reusable limes: An economical approach

About 20-30 kg of spent carbides is averagely generated per panel beater daily in Nigeria (West Africa). In this study, pure limes (quicklime and slaked lime) from spent carbide were obtained via lime cycle – calcination/ hydration. The spent carbide (wet) was collected from the panel beater's workshop at Yaba College of Technology, Lagos, Nigeria. 400 g to 600 g from these sieved particles were subjected to calcination at temperature ranges 950℃ and 1000℃. Slaking or hydration of 20 g of the calcined spent carbide was conducted in a pressure pot by varying water to sample ratio at separate times (30, 60, and 90 minutes). The obtained limes, CaO were characterized only by FTIR, and Ca (OH)2 was characterized by XRD and FTIR. The XRD spectrum of the synthesized slaked limes showed major peaks around 18o to 71.8o (2θ) with a dominant peak (011) plane at 34.1o (2θ). The crystallite size was found to be 56.55 nm, 56.56 nm, and 42.42 nm for samples A90, A60, and A30, respectively. FTIR spectroscopy of prepared samples (A30 and A60) showed sharp peaks viz-a-viz sample A90 at wave number 3637 cm-1 which is assigned to the presence of O―H stretching. The observed FTIR peak bands of the synthesized CaO at temperatures of 950oC (B950) and 1000oC (B1000) were found between the range of 1401.47 cm-1 and 998.92 cm-1, the presence of water molecules on the surface of the powder this also noticed in commercial CaO.

Investigating the mechanisms of hydraulicity regeneration in pure C3S paste

The study introduces a technique to regenerate hydraulicity in C3S by thermally treating powders from crushed hydrated alite cubes at various temperatures (ranging from 400 °C to 800 °C). Several characterization techniques, including XRD, FTIR, 29Si-NMR, SEM, and helium pycnometer were used to comprehend the mechanisms behind hydraulicity regeneration. XRD analysis showed anhydrous binder powders with β-C2S, Calcite, and calcium oxide phases after heat treatment, with β-C2S appearing at 600 °C. Hydration of regenerated binders resulted in Portlandite and Calcite phases, and the amorphous phase increased with curing due to the C-S-H formation confirmed by FTIR peaks. NMR analysis revealed distinct characteristics in TP800's C-S-H compared to the original C3S paste, primarily due to shorter chain lengths.

Machine learning-based performance evaluation and sludge characterization studies of oxidized starch-aluminum electrode assisted by direct current treatment of dye laden wastewater

The performance evaluation, sludge characterization and bi-optimization of treating dye-laden wastewater using oxidized starch-aluminum electrode assisted by direct current was investigated. Variables considered are current density (CD), wastewater pH, oxidized starch (OS) dosage and electrode inter-distance. Electrocoagulation batch reactor incorporated with jar test module was used for the experiment. FTIR, XRD and SEM were conducted to investigate structure, composition and morphology of starch and generated sludge. Sludge settling characteristics and filterability were studied. Response surface methodology (RSM) and artificial neural network (ANN) approach were used to optimize the process. The FTIR peaks revealed alcohol and carboxylic OH groups, while atomic structure indicated partly crystalline pattern. The results showed 96.22 % color removal using 6.6 mA/cm2 CD, 1.0 g/L OS, 4 cm inter-distance, and wastewater pH 4; 100 % COD removal using 4.4 mA/cm2 CD, 1.0 g/L OS, and 3 cm inter-distance at pH 7; and 99.99 % phosphate removal applying 2.2 mA/cm2 CD, 1.0 g/L OS, and 4 cm between electrode at pH 7. The sludge settling indicated lag, hindered, transition and compression zones, while sludge volume indices were less than 80 mg/g. The ANOVA revealed significant models with Prob > F < 0.0001 for color, COD and phosphate with R2 of 0.9741, 0.9819, and 0.9311, respectively. The ANN with superior R2 > 0.99 for all the response variables, indicated better optimization approach. From the forgoing, the use of combined technology; electro and chemical coagulation is beneficial toward achieving better result in the treatment of dye laden wastewater.

Evaluation of wear test on functionally graded metal-polymer tri-laminate composite interfaces of cooling-assisted friction stir additive manufacturing

In this study, a new friction stir welding (FSW) based additive manufacturing (AM) process called "cooling-assisted friction stir additive manufacturing (CA-FSAM)" was introduced to join sheets of metal-polymer hybrid structures (MPHS). Dry ice was introduced as the coolant. Thickness variations of the raw high-density polyethylene (HDPE) and 5083 aluminum alloy (Al5083) sheets were functionally graded at a rate of 0.75 mm from the former layer. The arrangement of layers in terms of thickness was arranged in the order of 3, 2.25, and 1.5 mm. Functionally graded metal-polymer tri-laminate composite fabricated with CA-FSAM technology was investigated using the pin-on-disk wear test. The results showed that mechanical locking between the layers affected the bond strength. Cross-sectional morphology examination revealed defect-free, strong joints. X-ray diffraction (XRD) results confirmed the formation of Mg2Si; however, the XRD peak was low, indicating a slight effect on the interface properties. Thermal gravimetric analysis (TGA)-Fourier transform infrared spectroscopy (FT-IR) characterization highlighted that the main evolved products during tri-laminate composite joining were CO, CC, CH3, CH2, and CH2. Oxidation occurred in the FTIR peak in the absorption band (1029.92 cm−1 to 1370.63 cm−1). Disk loading resulted in the buildup of an internal drag force that caused the dislocation/rupture of the CC or CH bonds. Defects, such as deep grooves, pits, and delamination at the interface, were observed in the composite specimen. The wear path was not visible in the worn composite material. The wear rate at 4 kg load on Al5083, HDPE, and metal-polymer tri-laminate composite specimens was 3.15 ± 0.22, 4.72 ± 0.36, and 3.42 ± 0.18 × 10−6 mm3/N. m, respectively.

Biodiesel production from microalgal biomass by Lewis acidic deep eutectic solvent catalysed direct transesterification

Traditional two steps biodiesel production process generally involves corrosive sulfuric acid in the transesterification step, which is not environmentally benign. In this work, a novel procedure was presented for the direct production of biodiesel using Lewis acid deep eutectic solvent (LADES) to avoid using sulfuric acid. Synergy between the Lewis site of the LADES catalyst and the Brønsted site from biomass pretreated by Brønsted acidic deep eutectic (BADES) has resulted in the development of a bifunctional medium considered to be appropriate for high biodiesel formation and increase the FAMEs weight. The mechanism of biodiesel formation was anticipated through the experimental and computational studies of Lewis and/or Brönsted acid sites in the reaction process. The potential interference factors of the extraction process such as time of reaction, temperature, LADES catalyst concentration in methanol, and solvent volume were further optimized experimentally, followed by the Box–Behnken method. The highest amount (39.86 mg/g) of fatty acid methyl esters (FAMEs) was obtained from Chlorella pyrenoidosa biomass at 120 °C for 90 min, 5 mL solvent volume, and 5% concentration of LADES (ChCl-CrCl3.6 H2O) catalyst in methanol. The predominant FAMEs were C16:0 (9.47 mg/g), C18:2 (12.42 mg/g), and C18:3 (8.68 mg/g), and obtained biodiesel qualities meet international standards. The recyclability of LADES was tested, and satisfactory results of FAME weight were observed up to three cycles, and the FTIR peaks of LADES catalyst after four cycles of reusing have shown the structure of DES remain stable. Despite the existence of sustainable, efficient, and less toxic ways for microalgae transesterification, further investigation is required to assess the scalability of these methods for large-scale use.

Detection and quantification of dicyandiamide (DCD) adulteration in milk using infrared spectroscopy: A rapid and cost-effective screening approach

Dicyandiamide (DCD) has been identified as a potential adulterant in milk. This study presents the development of a convenient, fast, and cost-effective FTIR-based screening method that considers both DCD tautomeric structures, given their relative stability in the ground state (with an energy difference of 288.68 kJ/mol between the two tautomers). The study identifies the 2200 cm−1 and 2160 cm−1 FTIR peaks of DCD as the most promising non-interfering peaks for calibration plots, effectively eliminating interference from the medium and possible adulterants. Density Functional Theory (DFT) studies using the B3LYP/6–31 G (d) method confirm that these two peaks correspond to N-C-N bond stretching in two DCD tautomers. Developed calibration plots for the 2160 cm−1 and 2200 cm−1 peak intensities and the integrated peak area versus DCD concentration show a strong positive linear relationship (2200 cm−1 = 0.9952, 2160 cm−1 = 0.9959, Area = 0.9981). This study highlights the utilization of the Area under the peak for both N-C-N stretching peaks, considering both tautomer structures. The novel FTIR-associated DCD detection method is grounded in simple linear regression theories and has been rigorously verified as an accurate, rapid, and cost-effective technique for screening DCD-adulterated milk samples using FTIR spectroscopy.

Preparation and Characterization of GX-50 and Vitamin C Co-encapsulated Microcapsules by a Water-in-Oil-in-Water (W1/O/W2) Double Emulsion-Complex Coacervation Method.

Co-encapsulated xanthoxylin (GX-50) and vitamin C (Vc) microcapsules (GX-50-Vc-M) were prepared by the combination of a water-in-oil-in-water (W1/O/W2) double emulsion with complex coacervation. The W1/O/W2 double emulsion was prepared by two-step emulsification, and it has a uniform particle size of 8.388 μm and high encapsulation efficiencies of GX-50 (85.95%) and Vc (67.35%) under optimized process conditions. Complex coacervation occurs at pHs 4.0-4.7, which has the highest encapsulation efficiency of GX-50 and Vc at pH 4.5. The complex coacervate with tannic acid solidifying (namely, wet microcapsules) has better mechanical properties and also enhances the ability of co-encapsulation of active ingredients. The resulting microcapsules by freeze-drying of wet microcapsules were characterized by UV-vis absorbance spectroscopy (UV-vis), Fourier infrared spectroscopy (FI-IR), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), X-ray diffraction (XRD), 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging, and in vitro permeation measurements. Under optimal conditions, the encapsulation efficiency and drug loading of GX-50-Vc-M for GX-50 and Vc are, respectively, 78.38 ± 0.51 and 59.34 ± 0.56%, and 35.6 ± 0.68 and 29.8 ± 0.92%. A slight shift in the FTIR peak between single GX-50 or Vc and GX-50-Vc-M confirmed the successful co-encapsulation of GX-50 and Vc in microcapsules. GX-50-Vc-M has bridged irregular spherical aggregates, while GX-50 and Vc are, respectively, encapsulated in hydrophobic and hydrophilic cavities of microcapsules in an amorphous dissolved state. GX-50-Vc-M has the highest DPPH· radical scavenging rate of 62.51%, and the scavenging process of GX-50-Vc-M on DPPH· radicals is more in line with the pseudo-second-order kinetic equation model. Moreover, the in vitro permeation of GX-50 and Vc in GX-50-Vc-M can reach maximum values of 40 and 60%, respectively. This concludes that GX-50-Vc-M is a promising delivery system for the penetration of the antioxidant into the deeper layers of the skin for the antioxidant effect.

Statistical glass structure gene modeling on liquidus temperature of high level waste glasses

Statistical glass structure gene modeling (GSgM) on liquidus temperature (TL) of simulated high level waste (HLW) glass is detailed in this article. TL values of a set of HLW borosilicate glasses were experimentally determined by x-ray diffraction (XRD) method with 24 h heat-treated glass in gradient temperature furnace, and the primary crystalline phase was CaMoO4. Integral peak areas obtained from the FTIR peak fitting were used as the structural data, and the statistical TL-structure model was first established. The S-P (TL) model was shown to have a high accuracy, i.e., R2 0.978, P value 0.0009 and RMSE 7.6 °C. Model validation showed the predicted and measured TL values were 960.4 °C and 965 °C, respectively. Model iteration further reduced P value to 0.0001 and RMSE to 7 °C. Relationship between composition (C) and the glass network structure (S) was then simulated, and composition-FTIR structure-TL analysis indicated that SiO2, ZnO, rB3+, MoO3, ZrO2, B2O3 and rare earth affect TL by influence the structural units Si–O–Si rocking vibrations, νs (Si–O–Si) in [SiO4] and νs ([BO3] or BO2O−). Results showed that GSgM offers an alternative approach to simulate TL of complex glass with limited experimental data, providing a plausible linkage between composition, structure and property.

Influence of Nanoparticle Size Distributions on the (in)Stability and Rheology of Colloidal SiO2 Dispersions and HPAM/SiO2 Nanofluid Hybrids

This study investigated the relationship between variations in the size distribution and the specific surface area of SiO2 nanoparticles and the in(stability) and rheology of their colloidal dispersions and their resulting silica-poly(acrylamide) hybrids. Thus, SiO2 nanoparticles with size distribution in the range 40-173 nm, corresponding to 70-26 m2/g of specific surface area, were used in the studies. The results show a correlation between the average particle size distribution/the specific surface area of silica nanoparticles with the in(stability) and the rheology of their dispersions, such that an increase in the particle size distribution from 40 to 173 nm corresponds to a decrease in dispersion instability index from 0.913 to 0.112. However, in the silica-poly(acrylamide) hybrids, a change in the particle size distribution from 40 to 173 nm corresponds to an increase in the nanofluid instability index from 0.1913 to 0.929. In the hybrid materials, interactions between polymer chains and nanoparticles lead to size-induced stability and rheological behaviour, such that the broadening of the FTIR peak around 1,000 cm-1 in the nanohybrids was related to an Si-O-H bending vibration that arose because of dominating hydrogen bonding arising from the interaction of the hydroxyl groups and the amide groups in the polymer. The rheological characteristics of the hybrid nanofluids show that the relative viscosity and shear sensitivity of the colloidal dispersions or their hybrids can be tailored by the average particle size distribution of the nanoparticles.

Preparation of bacterial cellulose-based antibacterial membranes with prolonged release of drugs: Emphasis on the chemical structure of drugs

Bacterial cellulose (BC) based antibacterial membranes were synthesized, including BC-cefoperazone (BC-CEF) and BC-cefoperazone sodium (BC-CEF/Na). To examine the various drug loading processes, the structure, morphology, and physical-chemical characteristics of membranes were evaluated. Results demonstrated that both types of medicines were successfully absorbed into membranes, and membranes displayed identical morphology and FT-IR peaks. BC-CEF showed lower crystalline of XRD, which was likely caused by the combination of carboxyl and hydroxyl. However, there were no drug peaks seen in the membranes, indicating no alteration of ribbon crystallization of BC. Two types of antibacterial membranes have significantly distinct drug-loading traits and drug-releasing profiles. The drug loading rate of CEF (46.4 mg/g) was significantly greater than CEF/Na (30.3 mg/g). The cumulative drug-releasing profiles showed that only BC-CEF continues to release drugs for a lengthy period up to 48 h and exhibited good antimicrobial activity against S. aureus and E. coli until 48 h. The cytotoxicity assay demonstrated the great biocompatibility of all membranes. Findings indicated that BC-CEF has the potential use as a prolonged biocide in the biomedical. The idea that BC membranes can naturally incorporate the carboxyl groups from antibiotics is also innovative and can be useful in developing of drug delivery systems.

Effect of different boron sources on the copper borates in solid-state synthesis

Abstract The copper borate of CuB2O4 in tetragonal form was successfully synthesized as a single-phase by using a solid-state method without using any modifying agent. For the designed experimental procedure, the optimized reaction conditions were estimated as a reaction temperature of 950 °C, reaction time of 240 min, argon atmosphere and Cu:B ratio of 1:5. The possible reaction mechanism estimated for both boron sources of boric acid and boron oxide. In both sets, the lower ratios of Cu:B supported CuB2O4 formation. In the use of boric acid as a boron source, higher reaction yield percentages (98 %) and lower particle sizes were determined. The micron-scale rounded particles were observed in morphological analyses and the particles were shaped in homogeneity in the use of boron oxide as a boron source. The specific FT-IR peaks were observed at the band values of 1190, 1035, 988, 945, 890, 695, 631, 540 and 479 cm−1. The experimental results highlighted the probable use of solid-state in the copper borate synthesis.