Antimicrobial Ionic Liquid-Based Materials for Biomedical Applications

Excessive and unwarranted administration of antibiotics has invigorated the evolution of multidrug-resistant microbes. There is, therefore, an urgent need for advanced active compounds. Ionic liquids with short-lived ion-pair structures are highly tunable and have diverse applications. Apart from their unique physicochemical features, the newly discovered biological activities of ionic liquids have fascinated biochemists, microbiologists, and medical scientists. In particular, their antimicrobial properties have opened new vistas in overcoming the current challenges associated with combating antibiotic-resistant pathogens. Discussions regarding ionic liquid derivatives in monomeric and polymeric forms with antimicrobial activities are presented here. The antimicrobial mechanism of ionic liquids and parameters that affect their antimicrobial activities, such as chain length, cation/anion type, cation density, and polymerization, are considered. The potential applications of ionic liquids in the biomedical arena, including regenerative medicine, biosensing, and drug/biomolecule delivery, are presented to stimulate the scientific community to further improve the antimicrobial efficacy of ionic liquids.     

POSS nanocrosslinked poly (ethylene glycol) hydrogel as hybrid material support for silver nanocatalyst

Silver nanoparticles supported on polyhedral oligomeric silsesquioxane (OA‐POSS) nanocrosslinked poly (ethylene glycol)‐based hydrogels (PEG₆₀₀‐POSS/Ag NPs) as novel nanohybrid catalysts were synthesized for the first time. The as‐prepared nanohybrid hydrogels were fully characterized by FT‐IR, SEM, EDX, XRD, TEM and TGA. PEG₆₀₀‐POSS/Ag NPs exhibited excellent catalytic performance for the reduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) in water at room temperature in the presence of borohydride.     

Mixed convection due to a rotating cylinder in a 3D corrugated cavity filled with single walled CNT-water nanofluid

Journal of Thermal Analysis and Calorimetry - Analysis of mixed convection due to a rotating inner cylinder in a corrugated three-dimensional cavity filled with carbon nanotube-water nanofluid was...     

Aluminum dodecatungstophosphate (AlPW12O40) as an efficient heterogeneous inorganic catalyst for the chemoselective synthesis of geminal diacetates (acylals) under solvent-free conditions

An efficient and chemoselective preparation of acylals from structurally different aldehydes in the presence of AlPW₁₂O₄₀ and acetic anhydride was achieved easily in high yields at room temperature under solvent-free conditions.     

Microwave-assisted synthesis of α-aminophosphinic acids from hypophosphorus acid salts under solvent free conditions

A simple, efficient, and general method has been developed for the synthesis of α-aminophosphinic acids from hypophosphorus salts under solvent-free conditions using microwave irradiation. α-Aminophosphinic acids were obtained in high yield under mild conditions by reaction of the amine salts of hypophosphorus acid with aldehydes in the presence of microwave irradiation.     

Aluminumdodecatungstophosphate (AlPW12O40) as a reusable Lewis acid catalyst: Facile regioselective ring opening of epoxides with alcohols, acetic acid and thiols

AlPW₁₂O₄₀ as a recyclable Lewis acid and stable solid compound was introduced for efficient ring opening of different epoxides with thiols, acetic acid, and primary, secondary, and tertiary alcohols. These processes were carried out at room temperature with high regio- and stereoselectivity.     

A note on De Vylder's method of estimation of IBNR claims

De Vylder's method of estimation of IBNR claims precludes consideration of independently established trends. A modification of this method is suggested by means of which an actuary would, in certain cases, combine a suspected trend with the available data to estimate IBNR claims. A numerical example is provided to demonstrate this modification.     

Lifshitz integral in closed forms

Closed forms of them-fold Lifshitz integral are given in terms of the hypergeometric function₂ F ₁ and in its arguments. The applicability of each form is discussed.On Sabbatical leave at Institute of Theoretical Physics, Johannes Kepler University, Linz, A-4040 Linz-Auhof, Austria.     

Study of the interaction between caesium bromide and kaolinite by differential thermal analysis

The reaction occurring during the wet grinding of kaolinite with CsBr was studied by simultaneous Differential Thermal Analysis -Thermogravimetry (DTA-TG), supplemented by infrared spectroscopy of isothermally treated CsBr disks. The DTA and TG curves were compared with those of untreated kaolinite and of kaolinite mixed or air ground with different alkali halides. A new endothermic DTA peak at 75–115°, accompanied by weight loss, is due to the desorption of surface and interparticle water located mainly at the interface between the mineral and the salt. A second endothermic peak at about 500° represents the simultaneous dehydroxylation of the clay and thermal hydrolysis of CsBr. The presence of a separate CsBr phase was identified from two endothermic peaks which characterize melting and boiling of the salt; only mixtures with more than 140 mmol CsBr per 100 g kaolinite show the presence of this phase. All of the CsBr below this concentration occurs in the CsBrHOH-kaolinite intercalation complex. This degree of saturation is smaller than that obtained previously for CsCl.

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Zusammenfassung Mittels simultaner DTA-TG wurde die sich während des Naßmahlens von Kaolinit mit CsBr stattfindende Reaktion untersucht, ergänzt durch IR-spektroskopische Untersuchungen von isotherm wärmebehandelten CsBr-Plättchen. Die DTA und TG Kurven wurden mit denen von unbehandeltem Kaolinit und von Kaolinit, vermischt oder an Luft gemahlen mit verschiedenen Alkalihalogeniden. Ein neuer endothermer DTA-Peak bei 75–115°C., begleitet von einem Gewichtsverlust, wird der Desorption von Oberflächen- oder interpartikelgebundenem Wasser zugeschrieben, das hauptsächlich an den Übergangsflächen Mineral/Salz lokalisiert ist. Ein zweiter endothermer Peak bei 500°C steht für die gleichzeitige Dehydroxylierung der Tonerde und die thermische Hydrolyse von CsBr. Aus zwei für Schmelzen und Sieden des Salzes charakteristischen endothermen Peaks konnte auf eine separate CsBr-Phase geschlossen werden; nur Gemische mit mehr als 141 mmol CsBr pro 100 g Kaolinit zeigen die Gegenwart einer solchen Phase. Unterhalb dieser Konzentrationsgrenze ist alles CsBr in CsBr-HOH-Kaolinit Durchdringungskomplexen vorhanden. Dieser Sättigungsgrad ist niedriger als der für CsCl.

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Dedicated to Professor Dr. H. J. Seifert on the occasion of his 60^th birthday

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S. Y. and A. N. are grateful to the Internal Fund of the Hebrew University of Jerusalem for financial support.     

Antioxidant activity of phenolic compounds from extracts of Eucalyptus globulus and Melaleuca styphelioides and their protective role on D-glucose-induced hyperglycemic stress and oxalate stress in NRK-49Fcells

Phytochemicals serve as potential therapeutic agents for the prevention and treatment of diseases. In this study, we elucidate the renoprotective activity of compounds isolated from Eucalyptus globulus and Melaleuca styphelioides extracts in glucose- and oxalate-challenged NRK-49F cell model. The antioxidant potential of isolated compounds was evaluated based on their effect on antioxidant enzyme activities and lipid peroxidation levels. The results demonstrated that exposure of NRK-49F cells to glucose and oxalate stress augmented cell damage and attenuated antioxidant enzyme activities. The phytochemicals 2,2,8-trimethyl-6-formyl-chrom-3-ene-7-O-β-D-glucopyranoside, Cornusiin B and tellimagrandin I treatment restored antioxidant enzyme activity, significantly lowered lipid peroxidation levels and effectively protected cells from glucose and oxalate stress equivalent to the known antioxidant, N-acetyl cysteine. Pterocarinin A significantly reversed cellular damage owing to glucose stress. In conclusion, the compounds isolated from E. globulus and M. styphelioides showed potential cytoprotective and anti-oxidative property against glucose- and oxalate-induced oxidative stress in NRK-49F cells.