Multidrug-Resistant Biofilm, Quorum Sensing, Quorum Quenching, and Antibacterial Activities of Indole Derivatives as Potential Eradication Approaches.

Challenges encountered in relapse of illness caused by resistance of microorganisms to antimicrobial agents (drugs) are due to factors of severe stress initiated by random use of antibiotics and insufficient beneficial approaches. These challenges have resulted to multiple drug resistance (MDR) and, subsequently, biofilm formation. A type of intercellular communication signal called quorum sensing (QS) has been studied to cause the spread of resistance, thereby enabling a formation of stable community for microorganisms. The QS could be inhibited using QS inhibitors (QSIs) called quorum-quenching (QQ). The QQ is an antibiofilm agent. Indole derivatives from plant sources can serve as quorum-quenching eradication approach for biofilm, as well as a promising nontoxic antibiofilm agent. In other words, phytochemicals in plants help to control and prevent biofilm formation. It could be recommended that combination strategies of these indoles' derivatives with antibiotics would yield enhanced results.

Inorganic Pb(II)-P and Pb(II)-S Complexes as Photosensitizers from Primary and Secondary Amines in Dyes-Sensitized Solar Cells.

Pb(II) complexes of bis(N-1,4-phenyl-N-(4-morpholinedithiocarbamato)) as Pb(II)-S and bis(N-diisopropyl-N-octyldithiocarbamato) as Pb(II)-P were prepared and characterized by optical, structural, morphological, and electrochemical techniques. The scanning electron microscopy analysis of Pb(II)-P and Pb(II)-S complexes consists of cubic crystals. X-ray diffraction and high-resolution transmission electron microscopy spectral studies revealed that the diameter increases in length for alkyl chain groups. This study demonstrates that the cubic shape of Pb(II) complexes can be synthesized from aromatic and aliphatic dithiocarbamate ligands. Photoluminescence analysis of both complexes fell within the blue shift region. The CV curve for Pb(II)-S revealed redox curves and the box-like shape as an indicative of a capacitive behavior, signifying limited catalytic redox activity. The J-V results for both sensitizers displayed satisfactory conversion efficiency (% η) between 3.77 and 3.96%.

Electrochemistry of Inorganic OCT-PbS/HDA and OCT-PbS Photosensitizers Thermalized from Bis(N-diisopropyl-N-octyldithiocarbamato) Pb(II) Molecular Precursors.

Inorganic nanocrystal solar cells have been tagged as the next generation of synthesizers that have the potential to break new ground in photovoltaic cells. This synthetic route offers a safe, easy and cost-effective method of achieving the desired material. The present work investigates the synthesis of inorganic PbS sensitizers through a molecular precursor route and their impact on improving the conversion efficiency in photovoltaic cells. PbS photosensitizers were deposited on TiO2 by direct deposition, and their structure, morphologies and electrocatalytic properties were examined. The X-ray diffraction (XRD) confirms PbS nanocrystal structure and the atomic force microscopy (AFM) displays the crystalline phase of uniform size and distribution of PbS, indicating compact surface nanoparticles. The electrocatalytic activity by lead sulfide, using N-di-isopropyl-N-octyldithiocarbamato (OCT) without hexadecylamine (HDA) capping (OCT-PbS) was very low in HI-30 electrolyte, due to its overpotential, while lead sulfide with OCT and HDA-capped (OCT-PbS/HDA) sensitizer exhibited significant electrocatalytic activity with moderate current peaks due to a considerable amount of reversibility. The OCT-PbS sensitizer exhibited a strong resistance interaction with the electrolyte, indicating very poor catalytic activity compared to the OCT-PbS/HDA sensitizer. The values of the open-circuit voltage (VOC) were ~0.52 V, with a fill factor of 0.33 for OCT-PbS/HDA. The better conversion efficiency displayed by OCT-PbS/HDA is due to its nanoporous nature which improves the device performance and stability.

Electrochemical Performance of Photovoltaic Cells using HDA Capped-SnS Nanocrystal from bis (N-1,4-Phenyl-N-Morpho-Dithiocarbamato) Sn(II) Complexes.

Great consideration is placed on the choice of capping agents' base on the proposed application, in order to cater to the particular surface, size, geometry, and functional group. Change in any of the above can influence the characteristics properties of the nanomaterials. The adoption of hexadecylamine (HDA) as a capping agent in single source precursor approach offers better quantum dots (QDs) sensitizer materials with good quantum efficiency photoluminescence and desirable particles size. Structural, morphological, and electrochemical instruments were used to evaluate the characterization and efficiency of the sensitizers. The cyclic voltammetry (CV) results display both reduction and oxidation peaks for both materials. XRD for SnS/HDA and SnS photosensitizers displays eleven peaks within the values of 27.02° to 66.05° for SnS/HDA and 26.03° to 66.04° for SnS in correlation to the orthorhombic structure. Current density-voltage (I-V) results for SnS/HDA exhibited a better performance compared to SnS sensitizers. Bode plot results indicate electrons lifetime (τ) for SnS/HDA photosensitizer have superiority to the SnS photosensitizer. The results connote that SnS/HDA exhibited a better performance compared to SnS sensitizers due to the presence of HDA capping agent.

The Frontiers of Nanomaterials (SnS, PbS and CuS) for Dye-Sensitized Solar Cell Applications: An Exciting New Infrared Material.

To date, extensive studies have been done on solar cells on how to harness the unpleasant climatic condition for the binary benefits of renewable energy sources and potential energy solutions. Photovoltaic (PV) is considered as, not only as the future of humanity's source of green energy, but also as a reliable solution to the energy crisis due to its sustainability, abundance, easy fabrication, cost-friendly and environmentally hazard-free nature. PV is grouped into first, second and third-generation cells. Dye-sensitized solar cells (DSSCs), classified as third-generation PV, have gained more ground in recent times. This is linked to their transparency, high efficiency, shape, being cost-friendly and flexibility of colour. However, further improvement of DSSCs by quantum dot sensitized solar cells (QDSSCs) has increased their efficiency through the use of semiconducting materials, such as quantum dots (QDs), as sensitizers. This has paved way for the fabrication of semiconducting QDs to replace the ideal DSSCs with quantum dot sensitized solar cells (QDSSCs). Moreover, there are no absolute photosensitizers that can cover all the infrared spectrum, the infusion of QD metal sulphides with better absorption could serve as a breakthrough. Metal sulphides, such as PbS, SnS and CuS QDs could be used as photosensitizers due to their strong near infrared (NIR) absorption properties. A few great dependable and reproducible routes to synthesize better QD size have attained much ground in the past and of late. The injection of these QD materials, which display (NIR) absorption with localized surface plasmon resonances (SPR), due to self-doped p-type carriers and photocatalytic activity could enhance the performance of the solar cell. This review will be focused on QDs in solar cell applications, the recent advances in the synthesis method, their stability, and long term prospects of QDSSCs efficiency.

Impact of Molybdenum Compounds as Anticancer Agents.

The aim of this mini review was to report the molybdenum compound intervention to control cancer disease. The intervention explains its roles and progress from inorganic molybdenum compounds via organomolybdenum complexes to its nanoparticles to control oesophageal cancer and breast cancer as case studies. Main contributions of molybdenum compounds as anticancer agents could be observed in their nanofibrous support with suitable physicochemical properties, combination therapy, and biosensors (biomarkers). Recent areas in anticancer drug design, which entail the uses of selected targets, were also surveyed and proposed.