Improving the safety efficacy ratio of existing drugs is a current challenge to be addressed rather than the development of novel drugs which involve much expense and time. The efficacy of drugs is affected by a number of factors such as their low aqueous solubility, unequal absorption along the gastrointestinal (GI) tract, risk of degradation in the acidic milieu of the stomach, low permeation of the drugs in the upper GI tract, systematic side effects, etc. This review aims to enlighten readers on the role of pH sensitive hydrogels in drug delivery, their mechanism of action, swelling, and drug release as a function of pH change along the GI tract. The basis for the selection of materials, their structural features, physical and chemical properties, the presence of ionic pendant groups, and the influence of their pK a and pK b values on the ionization, consequent swelling, and targeted drug release are also highlighted.

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Water pollution caused by heavy metal ions is becoming a serious threat to human and aquatic lives day by day.

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Injection molding of fiber-reinforced polymer composites is associated with the problem of fiber breakage. If the fiber length retained in the finish product is too short, it will limit the expected improvement in the property. Extrusion and pultrusion are two methods normally employed for the melt compounding of polymer composite feedstock for the injection molding and produced short- and long-fiber composites (SFCs and LFCs), respectively. In this work, short- and long-glass fiber-reinforced polyamide 6,6 composites were injection molded at different fiber loading and tested for the tensile properties, impact properties and fiber length characteristics. It was found that both tensile strength and tensile modulus of LFCs improved compared to the SFCs counterpart despite reduction in fracture strain, while pultrusion compounded composites also showed superior fiber characteristics, in terms of fiber length distribution, Ln, Lw, etc. compared to the extrusion compounded composites counterpart. Fiber length characteristics were also in agreement with the improvement in tensile strength and tensile modulus of LFCs over the SFCs. Impact properties of LFCs also show some improvement compared to the SFCs counterpart with equivalent composition, despite longer fiber retained in composites.

Pristine Mn2O3 and Ag-Mn2O3 composite thin films have been developed on fluorine doped tin oxide (FTO) coated glass substrates at 450 °C by aerosol assisted chemical vapor deposition (AACVD) using a methanol solution of a 1 : 2 mixture of acetatoargentate(i), Ag(CH3COO), and a newly synthesized manganese complex, [Mn(dmae)2(TFA)4] (1) (dmae = N,N-dimethylaminoethanolate, TFA = trifluoroacetate). The phase purity and stoichiometric composition of the films were investigated by X-ray diffraction (XRD) and Raman spectroscopy techniques. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses revealed a Ag to Mn ratio of 1 : 2 and further confirmed the uniform dispersion of Ag nanoparticles into the Mn2O3 structure. Optical studies showed a direct band gap of 2.0 eV for the pristine Mn2O3 film that was lowered to 1.8 eV for Ag-Mn2O3 due to the plasmonic interaction of Ag with Mn2O3. The Ag-Mn2O3 composite film displayed enhanced photocatalytic activity in photoelectrochemical (PEC) water splitting and yielded a photocurrent of 3 mA cm(-2) at 0.7 V versus Ag/AgCl which was 1.6 times higher than a pristine Mn2O3 film alone, under AM 1.5 G illumination (100 mW cm(-2)). The high PEC efficiency is mainly due to the plasmonic effect of Ag nanoparticles, which enhances the visible light absorption, efficient electron-hole separation and high carrier mobility of the Ag-Mn2O3 photoelectrode. The charge carrier density of Ag-Mn2O3 is two times higher than the pristine Mn2O3 as calculated by the Mott-Schottky plot. Based on the PEC studies a mechanism is proposed to elucidate the high activity of Ag-Mn2O3 in PEC water splitting.