Carbohydrate-based nanostructured catalysts: applications in organic transformations

The requirement of green and sustainable materials to prepare heterogeneous catalysts has intensified for practical reasons over the past few decades. Carbohydrates are possibly the most plentiful and renewable organic materials in nature with inimitable physiochemical properties, plausible low-cost and large-scale production, and sustainability features could be exploited in the generation of nanostructured heterogeneous catalysts. This review article outlines the organic transformations catalyzed by diverse carbohydrate-based nanostructured catalysts in greener and environmentally friendly processes. Selected examples are highlighted for a variety of organic reactions exploiting the proposed catalysts’ reactivity and reusability, and interactions with the intrinsic nature of the applied carbohydrate supports; advantages and speculated challenges of the introduced catalysts are deliberated as well.     

A Novel Bacterial Route to Synthesize Cu Nanoparticles and Their Antibacterial Activity

Journal of Cluster Science - This report focuses on a facile and one-pot way to synthesize stable Cu nanoparticles (NPs) through a bacterial approach using an inexpensive and non-toxic copper salt...     

Direct effect of nanoparticles on the thermal conductivity of CuO-water nanofluid in a phase transition phenomenon using molecular dynamics simulation

Journal of Thermal Analysis and Calorimetry - The thermal behavior of CuO-water nanofluid is examined on an aluminum surface. The dimensions of simulation boxes are...     

Synthesis and in vitro antibacterial evaluation of 6-substituted 4-amino-pyrazolo[3,4-<Emphasis Type="Italic">d</Emphasis>]pyrimidines

Pyrazolo[3,4-d]pyrimidines are one of the most important classes of fused heterocyclic compounds which exhibit a broad range of biological and medicinal properties. They are known as anticancer, antifungal, antibacterial, antiviral and anti-inflammatory agents. In this study, some new 6-substituted 4-amino-pyrazolo[3,4-d]pyrimidine derivatives were prepared via reaction of 5-amino-3-methyl-1-phenyl-1H-pyrazole-4-carbonitrile with various nitriles in the presence of sodium ethoxide as catalyst. The inhibitory properties of synthesized compounds were studied according to CLSI guidelines against some pathogenic bacteria including four gram-positive strains (Streptococcus pyogenes, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis subsp. spizizenii) and three gram-negative strains (Pseudomonas aeruginosa, Shigella flexneri and Salmonella enterica subsp. enterica). The antibacterial effects of all derivatives were compared with those of antibiotics belonging to different classes. The values were reported as inhibition zone diameter (IZD), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The effect of substituents on the biological activity of derivatives was discussed as well. The inhibitory effect of compound 6a, was shown to be the most, with MIC values in the range of 32–4096 μg/mL. Since most of the synthesized compounds were effective against Streptococcus pyogenes and Pseudomonas aeruginosa, they can be considered as inhibitors of these two bacteria.     

Alkanol-based supramolecular solvent microextraction of organophosphorus pesticides and their determination using high-performance liquid chromatography

A sensitive method for extraction and determination of three organophosphorus pesticides (chlorpyrifos, diazinon, phosalone) using a supramolecular solvent (SUPRAS) made of inverted hexagonal aggregates of alkanol and high-performance liquid chromatography with ultraviolet detection (HPLC–UV) was developed. The studied factors were alkanol amount, THF percentage (v/v), pH and vortex time. According to the full factorial design results, the effective parameters were alkanol amount, THF percentage (v/v) and pH. Then, a CCF was applied to obtain optimal conditions. The optimized conditions were obtained at 100 mg of alkanol, 5% of THF and pH 3.9. The limits of detection of pesticides were 0.5–1.3 ng/mL. The linearity was 1.6–500.0 ng/mL for different pesticides. Relative standard deviations for intra- and inter-day extraction of pesticides were 3.3–5.0 and 5.1–6.3, respectively, for five measurements. The method was also successfully applied for the determination of the pesticides in fruit juice and tap water samples.     

Coating Cellulosic Material with Ag Nanowires to Fabricate Wearable IR-Reflective Device for Personal Thermal Management: The Role of Coating Method and Loading Level

Textiles coated with silver nanowires (AgNWs) are effective at suppressing radiative heat loss without sacrificing breathability. Many reports present the applicability of AgNWs as IR-reflective wearable textiles, where such studies partially evaluate the parameters for practical usage for large-scale production. In this study, the effect of the two industrial coating methods and the loading value of AgNWs on the performance of AgNWs-coated fabric (AgNWs-CF) is reported. The AgNWs were synthesized by the polyol process and applied onto the surface of cotton fabric using either dip- or spray-coating methods with variable loading levels of AgNWs. X-ray diffraction, scanning electron microscopy (SEM), infrared (IR) reflectance, water vapor permeability (WVP), and electrical resistance properties were characterized. The results report the successful synthesis of AgNWs with a 30 μm length. The results also show that the spray coating method has a better performance for reflecting the IR radiation to the body, which increases with a greater loading level of the AgNWs. The antibacterial results show a good inhibition zone for cotton fabric coated by both methods, where the spray-coated fabric has a better performance overall. The results also show the coated fabric with AgNWs maintains the level of fabric breathability similar to control samples. AgNWs-CFs have potential utility for cold weather protective clothing in which heat dissipation is attenuated, along with applications such as wound dressing materials that provide antibacterial protection.     

Different binders in FCC catalyst preparation: impact on catalytic performance in VGO cracking

Research on Chemical Intermediates - In the present study, four different binders including two synthesized alumina-silica sol and two commercially available binders comprising LUDOX AS-30...     

Investigation and comparison of biological effects of regioselectively synthesized thiazole derivatives

In this study, anticancer, antibacterial (against hospital-isolated antibiotic-resistant Escherichia coli strains), antifungal, and antioxidant effects of synthesized heterocyclic compounds 5 and 7 containing thiazole core were examined. Cytotoxicity testing was utilized against MCF-7 breast cancer cells via MTT cell viability assay. Antibacterial and antifungal activities were checked out according to Clinical and Laboratory Standards Institute (CLSI) guidelines, and antioxidant properties were evaluated through scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals. Results showed the viability of breast cancer cell lines was reliant on concentration of heterocycles and time of incubation. Synthetic compounds exhibited excellent antibacterial and antifungal properties base on their minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) values as well as high antioxidant activities according to their IC₅₀ values. Higher anticancer and antibacterial properties were observed with compound 7; on the contrary, thiazole 5 had better antioxidant effects. They can be introduced as potent antimicrobial, antioxidant, and anticancer agents.     

Design and fabrication of a Fourier transform spectrometer by means of thermally actuated tunable grating

In this article, the design and fabrication of a Fourier transform spectrometer, based on a thermally actuated tunable grating, are presented. Grooves of a binary grating are filled with nitrobenzene, the refractive index of which highly depends on temperature. Through the application of heat, the temperature of the nitrobenzene is changed, which in turn changes the efficiency of the grating. To measure the spectrum of a light beam, the light under inspection is first passed through the grating and the intensity of the zero order of diffraction is recorded as a function of temperature. Next, the Fourier transform of the measured data is calculated. The resolution of the spectrometer is also discussed. Finally, a micro-spectrometer that is based on a thermally actuated grating is proposed.