Radiation‐Grafted Polymerization from a Gas Phase to Form Polymeric Layers on Metal Surfaces

Summary: Experimentally it is shown that, under irradiation in an atmosphere of non‐saturated vinylidene chloride vapors, a polymeric layer is formed on the surface of oxidized titanium samples. The thickness of this layer increases with the increase of thickness of the oxide film. Such a dependence corresponds to the current understanding of the mechanism of formation and migration of the active excited centers that initiate grafted polymerization.

Wide range XPS spectra of oxidized titanium samples after PVDC grafting from a gas phase.     

Phosphine-free Suzuki cross-coupling reaction: a mild and selective method for the carbon–carbon bond formation in aqueous tea extract

A mild and selective protocol has been developed for the palladium-catalyzed phosphine-free Suzuki cross-coupling reaction of aryl bromides with arylboronic acids in aqueous tea extract at room temperature. It is noteworthy that the aqueous tea extract plays an important role in the reaction, and various functional groups are tolerated under the optimized conditions. The reactions proceeded with very good chemoselectivity in favor of the bromo instead of the chloro group even at higher temperatures. Furthermore, this protocol could be applied to the cross-coupling of 4-bromoindole without protecting the base sensitive amine group with arylboronic acids in moderate to excellent yields.     

Regularity of a boundary point for quasilinear elliptic systems of the second order

There is considered a quasilinear elliptic system of the divergence type. There are obtained continuity conditions for a general solution and its gradient at a boundary point. These conditions depend on the geometry of the domain and also on the sparseness of eigenvalues of the coefficient matrix of the system.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 5, pp. 590–596, May, 1991.     

An efficient and one-pot synthesis of imidazolines and benzimidazoles via anaerobic oxidation of carbon-nitrogen bonds in water

The system, I₂/KI/K₂CO₃/H₂O, oxidizes carbon-nitrogen bonds for the synthesis of imidazolines and benzimidazoles from aldehydes and diamines under anaerobic conditions in water at 90 °C with excellent yields. The process is green, mild and inexpensive.     

Application of radioisotope XRF for the determination of noble metals in aqueous solutions

Radiometric methods of determination of platium and palladium (0.1 to 5% of Pt and 0.1 to 2% of Pd), gold and indium (0.01 to 1% of Au and 1 to 4 g In/l) and of platinum and rhodium (0.1 to 9% of Pt and 0.05 to 1% of Rh) in aqueous solution has been worked out. A suitable measuring device has been designed and constructed. The methods are based on the measurement of characteristic radiation of the L_α line for gold and platinum and of the K-series for indium, palladium and rhodium, as well as on the measurement of scattered radiation from a²³⁸Pu source. The r.m.s. error of the determination varies from 0.01 to 0.10% of Pt, 0.002 to 0.01% of Au and 0.01 to 0.15% of Pd depending on the concentration. In the case of Rh and In the errors are 0.008% and 0.04 g In/l, respectively.     

A Class of Subdifferential Inclusions for Elastic Unilateral Contact Problems

We consider a class of stationary subdifferential inclusions in a reflexive Banach space. We reformulate the problem in terms of a variational inequality with multivalued term and prove an existence result using the Kakutani-Fan-Glicksberg fixed point theorem. This approach allows to consider, in a natural way, a dual variational formulation of the problem. Next, we study the link between the primal and dual formulations and provide an equivalence result. Then, we consider a new mathematical model which describes the contact of an elastic body with a foundation. We apply the abstract formalism to derive the primal and the dual variational formulations of the problem, in terms of displacement and stress, respectively. Finally, we present existence and equivalence results in the study of this contact model.     

Engineering Design,Implementation, and Sensing Mechanisms of Wearable Bioelectronic Sensors in Clinical Settings

Wearable sensing devices have transformed the hourly analysis of events such as body signals and environmental risks into real-time monitoring in minutes or seconds. Wearable sensors have facilitated the ability to obtain useful data by monitoring the physiological parameters and activities of an aided and a healthy individual. Wearable devices employ detectable biomarkers in the human body, such as in tears, saliva, interstitial fluid, sweat, and so on. These can deliver relevant information on human health, online activity monitoring, and therapeutic treatments. This section outlines the significance of sample types and associated biomarkers as indicators in the development and manufacturing of wearable biosensors. We have emphasized the most recent advances of wearables based on skin-like and textile, giving attention to personalized health monitoring to record signals of motion and physiological and body fluid investigation. Furthermore, this review categorizes wearable biosensors based on the sensing mechanism, electrochemical, optical, and mechanical. Additionally, the recent wearables related to the detection of the newly havoc-causing pandemic, COVID-19, and the future perspective for the development of much more advanced and potent wearable biosensors have been highlighted. The final section highlights unmet difficulties and gaps in wearable sensors in personalized therapy.     

Hydrous zinc halide-catalyzed aminosulfonation of hydrocarbons

Benzylic and allylic hydrocarbons are selectively converted to the corresponding sulfonamides by a ZnBr(2)-H(2)O-catalyzed reaction with PhI[double bond, length as m-dash]NTs; saturated adamantane is aminosulfonated at the tertiary C-H bond.     

Sheet-forming abiotic hetero foldamers

Abiotic hetero oligomers, adopting a well-defined extended self-assembled sheet-like structure, derived from conformationally constrained aliphatic and aromatic amino acid residues repeating at regular intervals are reported.