Microwave-assisted ZnO-decorated carbon urchin resembling 'shish-kebab' morphology with self-healing and enhanced electromagnetic shielding properties.

Herein, inspired by Acacia auriculiformis fruit, the shish-kebab-like growth of ZnO on carbon urchin (ZnO@CU) was designed using microwave radiation, thus leading to a hierarchal 3D structure that can promote multiple internal reflections through polarization centers. This hierarchal structure was then dispersed in a designer polyetherimide (PEI) matrix containing dynamic covalent bonds that can undergo metathesis, triggered by temperature, to harness self-healing properties in the composite. Such key attributes are required for their potential use in EMI shielding applications where frequent repairs are indispensable. Morphological investigation revealed that the ZnO flower was periodically nucleated like 'shish-kebab' structures on CU surfaces. CU was designed from short carbon fibers using a facile modified method. The EMI shielding performance of the resulting composites was investigated in the X-band, illustrating a shielding effectiveness of -40.6 dB for 2 wt% of ZnO@CU loading, and the composite can be preserved after the self-healing procedure. The ZnO 'kebabs' on 'CU shish' facilitated multiple scattering and numerous polarization centers to improve the EMI shielding performances at extremely low filler contents. In addition, the mechanical and thermal properties of the composite showed improved structural integrity and superior resistance to extreme temperatures, respectively. Overall, the proposed ZnO@CU/PEI composite has great potential to fulfill the increasing demands for lightweight EMI shielding materials in many fields.

The FBXW7-NOTCH interactome: A ubiquitin proteasomal system-induced crosstalk modulating oncogenic transformation in human tissues.

BACKGROUND: Ubiquitin ligases or E3 ligases are well programmed to regulate molecular interactions that operate at a post-translational level. Skp, Cullin, F-box containing complex (or SCF complex) is a multidomain E3 ligase known to mediate the degradation of a wide range of proteins through the proteasomal pathway. The three-dimensional domain architecture of SCF family proteins suggests that it operates through a novel and adaptable "super-enzymatic" process that might respond to targeted therapeutic modalities in cancer. RECENT FINDINGS: Several F-box containing proteins have been characterized either as tumor suppressors (FBXW8, FBXL3, FBXW8, FBXL3, FBXO1, FBXO4, and FBXO18) or as oncogenes (FBXO5, FBXO9, and SKP2). Besides, F-box members like ßTrcP1 and ßTrcP2, the ones with context-dependent functionality, have also been studied and reported. FBXW7 is a well-studied F-box protein and is a tumor suppressor. FBXW7 regulates the activity of a range of substrates, such as c-Myc, cyclin E, mTOR, c-Jun, NOTCH, myeloid cell leukemia sequence-1 (MCL1), AURKA, NOTCH through the well-known ubiquitin-proteasome system (UPS)-mediated degradation pathway. NOTCH signaling is a primitive pathway that plays a crucial role in maintaining normal tissue homeostasis. FBXW7 regulates NOTCH protein activity by controlling its half-life, thereby maintaining optimum protein levels in tissue. However, aberrations in the FBXW7 or NOTCH expression levels can lead to poor prognosis and detrimental outcomes in patients. Therefore, the FBXW7-NOTCH axis has been a subject of intense study and research over the years, especially around the interactome's role in driving cancer development and progression. Several studies have reported the effect of FBXW7 and NOTCH mutations on normal tissue behavior. The current review attempts to critically analyze these mutations prognostic value in a wide range of tumors. Furthermore, the review summarizes the recent findings pertaining to the FBXW7 and NOTCH interactome and its involvement in phosphorylation-related events, cell cycle, proliferation, apoptosis, and metastasis. CONCLUSION: The review concludes by positioning FBXW7 as an effective diagnostic marker in tumors and by listing out recent advancements made in cancer therapeutics in identifying protocols targeting the FBXW7-NOTCH aberrations in tumors.

Morphological transitions of Bacillus subtilis in the presence of food-grade lipidic nanoemulsions.

The present study aims to study the antibacterial activity of food-grade lipidic nanoemulsion (noncationized/cationized) against Bacillus subtilis (BS). Bactericidal activity was ascertained by studying the morphological transitions on BS using transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Morphological changes were witnessed by cell wall breakage, oozing out of cellular contents, loss of cell turgidity and contour. Furthermore, aggregation of cationic nanoemulsion (CaNM) was preferentially observed at apical side of BS construing comparatively more electrostatic attraction between electronegative apical side and CaNM. Resistance response of BS exhibited by apical cell-wall thickening was not able to protect the bacteria due to leakage of cellular content. AFM corroborated its importance in bacteriology, wherein the fragmented cell wall can be "piece-by-piece" identified and sutured back to its appropriate vacant places, thereby, completing the cell wall contour of the ghost cell. Such postmortem analysis of bacterial cell using AFM studies can throw light toward mechanism of cell fragmentation of bacterial cells. SEM study also demonstrated the deformed, fragmented, and amorphous nature of BS construing the bactericidal effect of prepared nanoemulsion.

Optimizing photon upconversion by decoupling excimer formation and triplet triplet annihilation.

Perylene is a promising annihilator candidate for triplet-triplet annihilation photon upconversion, which has been successfully used in solar cells and in photocatalysis. Perylene can, however, form excimers, reducing the energy conversion efficiency and hindering further development of TTA-UC systems. Alkyl substitution of perylene can suppress excimer formation, but decelerate triplet energy transfer and triplet-triplet annihilation at the same time. Our results show that mono-substitution with small alkyl groups selectively blocks excimer formation without severly compromising the TTA-UC efficiency. The experimental results are complemented by DFT calculations, which demonstrate that excimer formation is suppressed by steric repulsion. The results demonstrate how the chemical structure can be modified to block unwanted intermolecular excited state relaxation pathways with minimal effect on the preferred ones.

Norbornadiene-Based Photoswitches with Exceptional Combination of Solar Spectrum Match and Long-Term Energy Storage.

Norbornadiene-quadricyclane (NBD-QC) photoswitches are candidates for applications in solar thermal energy storage. Functionally, they rely on an intramolecular [2+2] cycloaddition reaction, which couples the S0 landscape on the NBD side to the S1 landscape on the QC side of the reaction and vice-versa. This commonly results in an unfavourable correlation between the first absorption maximum and the barrier for thermal back-conversion. This work demonstrates that this correlation can be counteracted by using steric repulsion to hamper the rotational motion of the side groups along the back-conversion path. It is shown that this modification reduces the correlation between the effective back-conversion barrier and the first absorption maximum and also increases the back-conversion entropy. The resulting molecules exhibit exceptionally long half-lives for their metastable forms without significantly affecting other properties, most notably solar spectrum match and storage density.

Evaluation of phenolic composition, antioxidant, anti-inflammatory and anticancer activities of Polygonatum verticillatum (L.).

OBJECTIVE: Polygonatum verticillatum (L.) All. (Ruscaceae), one of the Ashtawarga plants, is widely used for treatment of various ailments. The present study was undertaken to determine the phenolic composition, antioxidant, anti-inflammatory and anticancer activities of several extracts (petroleum ether, dichloromethane, chloroform, ethanol, and aqueous) from the rhizomes of the plant. METHODS: Coarsely powdered dry rhizome was successively extracted with different solvents of increasing polarity (petroleum ether, dichloromethane, chloroform, ethanol and water). The phenolic compositions, in terms of total phenolic content (TPC), total flavonoid content (TFC) and total condensed tannin content (TTC), were evaluated with the Folin-Ciocalteu assay, aluminum chloride colorimetric assay and vanillin spectrophotometric assay, respectively. Total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays were used to assess the antioxidant potential of each extract. A protein denaturation model and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay were used to evaluate in vitro anti-inflammatory and anticancer activities, respectively. Gas chromatography-mass spectrometry (GC/MS) analysis was carried out to demonstrate various phytoconstituents in each extract. Correlation studies were also performed between phenolic composition (TPC, TFC and TTC) and different biological activities. RESULTS: Ethanol extract showed maximum TPC (0.126 mg/g, gallic acid equivalent in dry sample), TFC (0.094 mg/g, rutin equivalent in dry sample) and TTC (29.32 mg/g, catechin equivalent in dry sample), as well as antioxidant and anti-inflammatory properties. Chloroform extract exhibited the strongest cytotoxicity against the human breast cancer cell line, MCF-7. GC/MS analysis revealed the presence of 90 different phytoconstituents among the extracts. Antioxidant and anti-inflammatory activities had a positive correlation with TPC, TFC and TTC. However, the anticancer activity showed a negative correlation with TPC, TFC and TTC. CONCLUSION: From the present study, it can be concluded that P. verticillatum possessed remarkable antioxidant, anti-inflammatory, and anticancer activities, which could be due to different secondary metabolites of the plant. Phenolic compounds are likely responsible for antioxidant and anti-inflammatory activities. However, flavonoids and other compounds might contribute to the anticancer potential of the plant.

Charge transport and structure in semimetallic polymers.

Owing to changes in their chemistry and structure, polymers can be fabricated to demonstrate vastly different electrical conductivities over many orders of magnitude. At the high end of conductivity is the class of conducting polymers, which are ideal candidates for many applications in low-cost electronics. Here, we report the influence of the nature of the doping anion at high doping levels within the semi-metallic conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) on its electronic transport properties. Hall effect measurements on a variety of PEDOT samples show that the choice of doping anion can lead to an order of magnitude enhancement in the charge carrier mobility > 3 cm2/Vs at conductivities approaching 3000 S/cm under ambient conditions. Grazing Incidence Wide Angle X-ray Scattering, Density Functional Theory calculations, and Molecular Dynamics simulations indicate that the chosen doping anion modifies the way PEDOT chains stack together. This link between structure and specific anion doping at high doping levels has ramifications for the fabrication of conducting polymer-based devices. © 2017 The Authors. Journal of Polymer Science Part B: Polymer Physics Published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 97-104.

Experimental design-based optimization of lipid nanocarrier as delivery system against Mycobacterium species: in vitro and in vivo evaluation.

The study aimed to optimize self-nanoemulsifying drug delivery system using experimental design using excipients holding innate anti-mycobacterium activities followed with characterizations for responses such as optical clarity (Y1), zone of inhibition (ZOI) against Mycobacterium smegmatis strains (Y2, Y3), and globular size (Y4). The optimized formulations (OF1-OF3) were further characterized for responses and evaluated for zeta potential, minimum inhibition concentration (MIC) against non-pathogenic and tubercular strains, morphological (electron microscopy and atomic force microscopy), and confocal laser scanning microscopy (CLSM) studies. The desirability analysis suggested that the predicted values of the OF1 for the responses Y1, Y2, Y3, and Y4 were 0.137, 22.77 mm, 21.9 mm, and 191.11 nm, respectively. The morphological assessment confirmed the in vitro studies and established the inhibition mechanism as evidenced with oozing, ablation, and cell-wall fragmentation followed with cell disruption. The OF1, OF2, and OF3 showed an MIC value at 8.8 ± 0.56 mg/ml, 12.5 ± 0.22 mg/ml, and 15.0 ± 0.4 mg/ml, respectively, corroborating effectiveness against tubercular strain. CLSM studies revealed 75.1, 80.3, and 88.7% as an intense fluorescence intensity of OF1, OF2, and OF3, respectively, as compared with dye solution (∼53%). Conclusively, it can be inferred that the delivery of anti-tubercular drugs might be reassessed using excipients with inherent anti-mycobacterium activities.

Huntington's disease: an update of therapeutic strategies.

Huntington's disease (HD) is an autosomal dominant triplet repeat genetic disease, which results in progressive neuronal degeneration in the neostriatum and neocortex, and associated functional impairments in motor, cognitive, and psychiatric domains. Although the genetic mutation caused by abnormal CAG expansion within the htt gene on chromosome 4p16.3 is identified, the mechanism by which this leads to neuronal cell death and the question of why striatal neurones are targeted both remain unknown. Patients manifest a typical phenotype of sporadic, rapid, involuntary control of limb movement, stiffness of limbs, impaired cognition and severe psychiatric disturbances. There have been a number of therapeutic advances in the treatment of HD, such as fetal neural transplantation, RNA interference (RNAi) and transglutaminase inhibitors (Tgasei). Although there is intensive research into HD and recent findings seem promising, effective therapeutic strategies may not be developed until the next few decades.