Light-absorption-driven photocatalysis and antimicrobial potential of PVP-capped zinc oxide nanoparticles.

Toxic dyes in water bodies and bacterial pathogens pose serious global challenges to human health and the environment. Zinc oxide nanoparticles (ZnO NPs) demonstrate remarkable photocatalytic and antibacterial potency against reactive dyes and bacterial strains. In this work, PVP-ZnO NPs have been prepared via the co-precipitation method using polyvinylpyrrolidone (PVP) as a surfactant. The NPs' microstructure and morphology were studied using X-ray diffraction (XRD), having a size of 22.13 nm. High-resolution transmission electron microscope (HR-TEM) and field emission scanning electron microscopy (FESEM) analysis showed spherical-shaped PVP-ZnO NPs with sizer ranging from 20 to 30 nm. Fourier Transform Infrared Spectroscopy (FT-IR) confirmed the hybrid nature of the NPs, and UV-Vis spectroscopy showed an absorption peak at 367 nm. The PVP-ZnO NPs exhibited high photocatalytic activity, achieving 88% and nearly 95% degradation of reactive red-141 azo dye with 10 mg and 20 mg catalyst dosages, respectively. The antibacterial properties of the NPs were demonstrated against Escherichia coli and Bacillus subtilis, with inhibition zones of 24 mm and 20 mm, respectively. These findings suggest that PVP-ZnO NPs can be effectively used for water treatment, targeting both dye and pathogenic contaminants.

Measuring the Impact of Augmented Reality in Flipped Learning Mode on Critical Thinking, Learning Motivation, and Knowledge of Engineering Students.

Digital electronics is a fundamental subject for engineering students, and it enables the students to learn design-based approaches and solve complex engineering problems. Students learn about minimization techniques for reducing the hardware components and size of the circuit by solving complex Boolean equations. The Karnaugh map (K-map) is one such technique utilized in digital electronics to solve complex Boolean equations and design AND-OR-INVERT (AOI) logical diagrams. The K-map technique involves several steps to solve the Boolean expression, and students often find it difficult to follow the K-map process. In this study, an AR-based learning system was developed using Unity 3D and Vuforia SDK that aimed to teach the students about the step-wise operation of the K-map technique. An experimental study was conducted with 128 undergraduate engineering students to determine the impact of the AR learning system on the critical thinking skills, learning motivation, and knowledge gain of students. The students were divided into two groups: experimental group (N = 64) and control group (N = 64). The AR learning system was implemented in flipped learning mode and utilized to provide in-class activities during the learning. The experimental group students utilized the AR learning system for in-class activities whereas control group students performed in-class activities using the traditional approach. The experimental outcomes indicate that the use of AR technology has a significant positive impact on the critical thinking skills, learning motivation, and knowledge gain of students. The study also found that critical thinking skills and learning motivation have a significant positive correlation with the knowledge gain of students in the experimental group.

ZnO and cobalt decorated ZnO NPs: Synthesis, photocatalysis and antimicrobial applications.

The rapid growth of pollutants, both biological and non-biological, puts environmental systems in jeopardy. In view of this, the current study demonstrates the synthesis of undoped and Cobalt-doped zinc oxide nanoparticles (Co doped ZnO NPs) via co-precipitation method. The confirmation of incorporation of the Co dopant into ZnO NPs was verified through various spectroscopic and microscopic techniques. UV-absorption spectra of cobalt-doped ZnO NPs revealed a red shift with change of absorption spectra from 356 nm to 377 nm as compared to undoped ZnO NPs. XRD studies inferred that the average crystallite size of 0.5% and 1% Co-doped ZnO powder was obtained to be ∼16 nm and 14 nm respectively. A drop in band gap value from 3.48 eV to 3.30 eV provided as substantive evidence of the successful integration of Co2+ ions inside the ZnO matrix. FESEM and HRTEM studies revealed that the obtained ZnO NPs are in narrow size distribution (15-20 nm) with a wurtzite crystal structure. The synthesized ZnO and Co-ZnO NPs showed excellent photocatalytic and antimicrobial potency towards reactive brown dye (RB-1) and two bacterial strains, respectively. 1% Co-doped ZnO demonstrated the maximum photocatalytic activity (∼95%), in contrast to 0.5% Co-doped ZnO and undoped ZnO. Thus, the findings of this work support the developed system has a dual role as the photocatalyst, and antibacterial agent for efficient environmental remediation.

Sustainable synthesis of biogenic ZnO NPs for mitigation of emerging pollutants and pathogens.

Groundwater pollution is mostly caused by overuse of fertilizers, pesticides, contemporary agricultural practices, anthropogenic activities, home waste disposal, and the rapid expansion of the chemical industry. Drinking tainted water on a regular basis can have detrimental consequences on human health as well on environment. Nanoparticles (NPs) based contaminants alleviation strategy found to be most efficient, cost-effective and reliable. In this study, ZnO NPs were synthesized via citrus limon leaves extract as a sustainable/cost-effective method. Diverse microscopic and spectroscopic studies confirmed the formation of spherical ZnO NPs with size range 15-25 nm. Reactive green-19 (RG-19) was degraded photocatalytically under direct solar irradiation (degradation efficiency âˆ¼ 92%, rate constant 0.03 min -1, 80 min) in the presence of ZnO NPs. These ZnO NPs also demonstrated highly substantial antibacterial action against two pathogenic Gram-positive (Bacillus subtilis, zone of clearance: 8.6 mm) and Gram-negative (Escherichia coli, zone of clearance: 9.8 mm) bacteria. Thus, the present study demonstrates the effective/sustainable NPs based platform for water remediation.

Identification of a cross-talk between EGFR and Wnt/beta-catenin signaling pathways in HepG2 liver cancer cells.

EGFRis a transmembrane receptor tyrosine kinase involved in regulating cell proliferation, differentiation and survival. EGFR is actively pursued as a therapeutic target because its aberrant expression or activity has been reported in several cancers. Several studies have reported the nuclear localization of the EGFR in various cell types, however, its exact nuclear functions are not clear yet. In this study, we have generated GFP fusion constructs of EGFR and its mutants to analyze their subcellular localizationin normal and cancer cells and impact of its sub-cellular location on its various activities using immunoblotting, confocal microscopy, reporter assays, loss-of-function EGFR mutants, and EGFR specific small molecule inhibitors. We show that EGFR is involved in modulating TCF dependent ß-catenin transcriptional activity in HepG2 cells in a similar fashion as IGF1R tyrosine kinase. Moreover, we show that cytoplasmic and nuclear functions are two independent activities of EGFR.

Combined Parietal-Insular-Striatal Cortex Stroke with New-Onset Hallucinations: Supporting the Salience Network Model of Schizophrenia.

Brain imaging studies have identified multiple neuronal networks and circuits in the brain with altered functioning in patients with schizophrenia. These include the hippocampo-cerebello-cortical circuit, the prefrontal-thalamic-cerebellar circuit, functional integration in the bilateral caudate nucleus, and the salience network consisting of the insular cortex, parietal anterior cingulate cortex, and striatum, as well as limbic structures. Attributing psychotic symptoms to any of these networks in schizophrenia is confounded by the disruption of these networks in schizophrenic patients. Such attribution can be done with isolated dysfunction in any of these networks with concurrent psychotic symptoms. We present the case of a patient who presents with new-onset hallucinations and a stroke in brain regions similar to the salience network (insular cortex, parietal cortex, and striatum). The implication of these findings in isolating psychotic symptoms of the salience network is discussed.

Identification of a unique loss-of-function mutation in IGF1R and a crosstalk between IGF1R and Wnt/ß-catenin signaling pathways.

IGF1R is a ubiquitous receptor tyrosine kinase that plays critical roles in cell proliferation, growth and survival. Clinical studies have demonstrated upregulation of IGF1R mediated signaling in a number of malignancies including colon, breast, and lung cancers. Overexpression of the IGF1R in these malignancies is associated with a poor prognosis and overall survival. IGF1R specific kinase inhibitors have failed in multiple clinical trials partly because of the complex nature of IGF1R signaling. Thus identifying new binding partners and allosteric sites on IGF1R are emerging areas of research. More recently, IGF1R has been shown to translocate into the nucleus and perform many functions. In this study, we generated a library of IGF1R deletion and point mutants to examine IGF1R subcellular localization and activation of downstream signaling pathways. We show that the nuclear localization of IGF1R is primarily defined by its cytoplasmic domain. We identified a cross-talk between IGF1R and Wnt/ß-catenin signaling pathways and showed, for the first time, that IGF1R is associated with upregulation of TCF-mediated ß-catenin transcriptional activity. Using loss-of-function mutants, deletion analysis and IGF1R specific inhibitor(s), we show that cytoplasmic and nuclear activities are two independent functions of IGF1R. Furthermore, we identified a unique loss-of-function mutation in IGF1R. This unique loss-of-function mutant retains only nuclear functions and sits in a pocket, outside ATP and substrate binding region, that is suited for designing allosteric inhibitors of IGF1R.

Terminal regions of ß-catenin are critical for regulating its adhesion and transcription functions.

ß-Catenin, the central molecule of canonical Wnt signaling pathway, has multiple binding partners and performs many roles in the cell. Apart from being a transcriptional activator, ß-catenin acts as a crucial effector component of cadherin/catenin complex to physically interact with actin cytoskeleton along with α-catenin and E-cadherin for regulating cell-cell adhesion. Here, we have generated a library of ß-catenin point and deletion mutants to delineate regions within ß-catenin that are important for α-catenin-ß-catenin interaction, nuclear localization, and transcriptional activity of ß-catenin. We observed a unique mechanism for nuclear localization of ß-catenin and its mutants and show that N-terminal exon-3 region and C-terminal domain of ß-catenin are critical for this activity of ß-catenin. Furthermore, we show HepG2 cells have high ß-catenin mediated transcriptional activity due to the presence of an interstitial deletion at the N-terminal region of ß-catenin. Due to this deletion mutant (hereupon called TM), GSK3ß and HDAC inhibitors failed to show any impact whereas curcumin significantly inhibited ß-catenin mediated transcriptional activity reiterating that TM is primarily responsible for the high transcriptional activity of HepG2 cells. Moreover, we show the recombinant TM does not physically interact with α-catenin, localizes predominantly in the nucleus, and has nearly two-fold higher transcriptional activity than the wildtype ß-catenin.

Dynamics of GFP-Fusion p110α and p110ß Isoforms of PI3K Signaling Pathway in Normal and Cancer Cells.

Cancer therapeutics is a hot subject and PI3K class 1A isoforms (p110α and p110ß) are pursued as major targets. Genetic analysis, biochemical approaches, and structural studies have demonstrated crucial roles for these isoforms in several physiological processes. p110α is critical for insulin signaling, whereas p110ß is essential for the growth and differs from p110α in many ways. Here, we have generated GFP-fusion clones of wildtype and mutant version of p110α and p110ß and expressed them in HEK293 and cancer cells to examine their subcellular localization and their impact on downstream signaling. In HEK293 cells, p110ß GFP-fusion protein is translocated into the nucleus, whereas p110α-GFP stays exclusively in the cytoplasm. This study demonstrates that p110α and p110ß oncogenecity, kinase activity, and interaction with p85 regulatory subunit does not have any impact on their subcellular localization. PI3K pathway specific inhibitor, LY294002, abrogated PI3K signaling by reducing pAkt levels, however, the subcellular localization of p110α and p110ß remained unchanged. Furthermore, we analyzed the expression of recombinant p110α and p110ß in a panel of human cancer cells and observed remarkable differences in their expression levels. The differential expression of recombinant p110α and p110ß was observed to be mainly regulated by the endogenous levels of pAkt. Unlike in HEK293, p110α showed nuclear localization in cancer cells in a similar fashion to p110ß. Moreover, we observed the PI3K signaling activities in low pAkt expressing cells are mediated by PDK1 and S6K proteins. Finally, p110α and p110ß were seen to play an essential role in promoting the cell cycle progression in MCF-7 and HCT-116 cells. J. Cell. Biochem. 117: 2864-2874, 2016. © 2016 Wiley Periodicals, Inc.

Antioxidant and antimicrobial properties of the essential oil and extracts of Zanthoxylum alatum grown in north-western Himalaya.

The essential oil obtained from the fresh leaves of Zanthoxylum alatum was analysed by gas chromatography/mass spectrometry (GC/MS). Fourteen components were identified, and linalool (30.58%), 2-decanone (20.85%), ß -fenchol (9.43%), 2-tridecanone (8.86%), ß -phellandrene (5.99%), Sabinene (4.82%), and α -pinene (4.11%) were the main components. The EO and methanolic extract of Z. alatum exhibited potent antifungal activity against Alternaria alternata, Alternaria brassicae, and Curvularia lunata. The EO also showed significant antibacterial activity against Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, and Escherichia coli. Further, antimicrobial constituents of the EO were isolated by bioautography and preparative thin layer chromatography (PTLC) and identified as ß -fenchol and linalool using GC/MS analysis. In addition to this, the free radical scavenging activity and antioxidant potential of EO and methanolic extract/fractions of Z. alatum were also investigated using in vitro assays including scavenging ability against DPPH(•), reducing power and chelating ability on Fe(2+) ions. Our results demonstrate that Z. alatum could be used as a resource of antioxidant and antimicrobial compounds which may find applications in food and pesticide industries.

Antioxidant activity and protective effect against plasmid DNA strand scission of leaf, bark, and heartwood extracts from Acacia catechu.

UNLABELLED: The antioxidant activity of methanol extract/fractions of leaf, bark, and heartwood of Acacia catechu was evaluated by various antioxidant assays, including free radical, superoxide and hydroxyl radical, reducing power, metal ion chelation, as well as hydroxyl radical induced DNA strand scission. The leaf, bark, and heartwood powder was extracted in methanol and the lyophilized methanol extract was fractionated with different solvents in the order of increasing polarity. The results indicate that ethyl acetate fraction of heartwood has the highest antioxidant capacities, presenting lower EC(50) values particularly in free radical scavenging activity, including DPPH radicals (4.76 ± 0.14 µg/mL), superoxide anions (26.21 ± 0.79 µg/mL), and hydroxyl radicals (33.69 ± 1.42 µg/mL), in direct assay systems. Reducing power was also highest in ethyl acetate fraction of heartwood (EC(50) of 79.05 ± 1.02 µg/mL). As for the chelating power on ferrous ions, leaf extract was more effective than bark and heartwood extracts. Furthermore, the ethyl acetate and acetone fractions of heartwood significantly protected pBR322 supercoiled plasmid DNA against strand scission induced by hydroxyl radicals in a Fenton's reaction mixture. PRACTICAL APPLICATION: The present investigation suggests that the three organs of A. catechu differ significantly in their antioxidant potential as seen in the DPPH radical scavenging assay, reducing power assay, metal ion chelating assay, superoxide radical scavenging assay and hydroxyl radical scavenging assay. Further, our results showed that crude methanol extract and ethyl acetate fraction of heartwood of A. catechu might have a good potential as a source for natural health products due to its antioxidant and DNA protective activities.