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1.
Langmuir ; 39(32): 11414-11425, 2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37527487

ABSTRACT

Ferroelectric materials have gained significant interest in various kinds of water splitting, but the study of ferroelectric materials for electrocatalytic water splitting is in its infancy. Ferroelectric materials have spontaneous polarization below their Curie temperature due to dipolar alignment, which results in surface charges. In 2D ferroelectric materials, spontaneous polarization depends on thickness. Herein, we report that thickness-dependent ferroelectric polarization in 2D nanosheets can also accelerate the oxygen evolution reaction (OER) along with the tailored active surface area of exposed crystalline facets, which improves the electrocatalytic activity relatively. Iron-substituted BiOCl nanosheets of varying thickness are fabricated by varying the pH using a facile coprecipitation method. The substituted iron enhances polarization and electrochemical active sites on the surface. The findings in this study show that the exposed (001) facet and higher thickness of the nanosheets have high ferroelectric polarization and, in turn, superior electrocatalytic activity and remarkable stability, requiring low overpotentials (348 mV and 270 mV at 100 mA/cm2 and 10 mA/cm2) in alkaline (1.0 M KOH) electrolyte. As the thickness of the nanosheets is decreased from 140 to 34 nm, the electrocatalytic performance of iron-substituted BiOCl nanosheets starts to reduce due to the lower Coulomb-Coulomb interaction and the increasing depolarization.

2.
ACS Appl Bio Mater ; 6(5): 1943-1952, 2023 05 15.
Article in English | MEDLINE | ID: mdl-37126316

ABSTRACT

Theranostic nanoparticulate systems (TNPs) have shown potential in addressing problems related to spatial localization and temporally controlled release of drugs with the capabilities of real-time imaging to evaluate the progress of therapy. The current study reports the ultrasonic atomization-led synthesis of in vitro and in vivo evaluations of ultrasmall chitosan-based theranostic nanohybrid formulations with encapsulated doxorubicin (DOX) and iron-oxide magnetic nanoparticles. The nanohybrid particles are characterized using transmission electron microscopy, powder X-ray diffraction, FTIR, DOX encapsulation efficiency, in vitro release, cellular uptake, and toxicity. These formulations were also tested for the capability of invivo tumor reduction and simultaneous magnetic resonance imaging using Swiss albino mice. Ultrasonic atomizer-led synthesis resulted in chitosan-magnetic nanohybrids (CMNPs) having sizes of 15 ± 3 nm which comprise MNP of 10 ± 3 nm. The encapsulation of DOX in CMNP was around 25%, resulting in an 80% sustained release over 10 days at pH 5 and 7. CMNP was also found to be an efficient DOX delivery vehicle tested on cancer cells (HeLa). The CMNPs were able to reduce the tumor volume by 60% in 15 days. The inherent magnetic property and nanoscale size of CMNPs also provided for enhanced contrast efficiency in magnetic resonance imaging of tumors. Thus, such multifunctional theranostic nanoparticles can be an efficient tool for targeted diagnostic and therapeutic success.


Subject(s)
Chitosan , Precision Medicine , Animals , Mice , Chitosan/chemistry , Ultrasonics , Drug Delivery Systems , Doxorubicin/chemistry , Magnetic Resonance Imaging
3.
Drug Deliv Transl Res ; 12(7): 1588-1604, 2022 07.
Article in English | MEDLINE | ID: mdl-34537930

ABSTRACT

The most challenging task in targeting the brain is trespassing the blood-brain barrier (BBB) which restricts the movement of about 98% small molecules. Targeting the central nervous system using magnetic nanoparticles may deliver the drug to the target site along with a contrast imaging property. The use of magnetic nanoparticles can become non-invasive drug targeting and a bio-imaging method for brain cancer. The strategy to apply polymeric nanoparticles as a carrier of magnetic iron oxide nanoparticles can be a promising tool as a multitherapeutic drug delivery approach involving delivery of chemotherapeutic drugs with a magnetic targeting approach, imaging, and hyperthermia. This review will highlight the existing difficulties/barriers in crossing the BBB, types of magnetic materials, polymeric carriers for functionalization of magnetic nanoparticles, and targeting strategies as therapeutic and imaging modalities. Utilization of polymeric magnetic nanoparticles as an efficient targeting platform for better drug delivery and imaging for brain cancer and future prospects are also discussed. Polymeric magnetic nanoparticles as a drug delivery and bio-imaging vehicle for brain cancer.


Subject(s)
Brain Neoplasms , Magnetite Nanoparticles , Nanoparticles , Blood-Brain Barrier , Brain/pathology , Brain Neoplasms/diagnostic imaging , Brain Neoplasms/drug therapy , Drug Carriers , Drug Delivery Systems/methods , Humans , Polymers
4.
Behav Anal Pract ; 14(4): 893-912, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34394851

ABSTRACT

Due to the coronavirus (COVID-19) pandemic, around the middle of March 2020, in-clinic intervention services based in applied behavior analysis provided to children had to be stopped abruptly in India. This qualitative and quantitative case study details how Behavior Momentum India (BMI), an organisation providing ABA-based interventions, transitioned services from in clinic to telehealth while continuing to target each student's skill acquisition goals in language and communication domains. A cohort of 92 students diagnosed with autism or other learning disabilities participated in this study; 51 therapists, 9 behavior supervisors, and a doctoral-level Board Certified Behavior Analyst collaborated with parents; 78% of the students and 82% of the therapists used smartphones; and only a few used iPads and laptops. Therapists conducted direct sessions and parent-mediated sessions with 82 students. With 10 students, behavior supervisors trained parents to implement interventions with their children. The critical transition decisions, logistics, and ethical challenges were identified using qualitative methods. Despite significantly reduced session durations, all students continued to acquire targeted skills, and 52% of the students acquired more skills in telehealth compared to in clinic. A parent satisfaction survey returned high ratings onour organization's initiative, and 72% of the parents reported that their familiarity and confidence with the science of applied behavior analysis had increased.

5.
Protein Expr Purif ; 186: 105929, 2021 10.
Article in English | MEDLINE | ID: mdl-34139322

ABSTRACT

Accumulation and exposure of organophosphate pesticides are of great concern today owing to their abundant usage and potential health hazards. Harmful effects of organophosphate pesticide exposure and limitations of the available treatment methods necessitate the development of reliable, selective, cost-effective, and sensitive methods of detection. We developed a novel biosensor based on the enzymatic action of recombinant organophosphorus hydrolase (OPH) expressed in E. coli. We report the development of colorimetric biosensors made of His-Nus-OPH as well as His-Nus-OPH loaded alginate microspheres. The colorimetric detection method developed using solution-phase and alginate-encapsulated His-Nus-OPH exhibited detection limits of 0.045 and 0.039 mM, respectively, for ethyl paraoxon, and 0.101 and 0.049 mM, respectively, for methyl parathion. Additionally, fluorescence measurement using pH-sensitive fluorescein isothiocyanate (FITC) was used to sense the quantity of organophosphorus pesticides. The fluorometric detection method using solution-phase His-Nus-OPH, with ethyl paraoxon and methyl parathion as the substrate, reveals the lower limit of detection as 0.014 mM and 0.044 mM, respectively. Our results demonstrate the viability of His-Nus-OPH for OP detection with good sensitivity, LOD, and linear range. We report the first use of N-terminal His-NusA-tagged OPH, which enhances solubility significantly and presents a significant advance for the scientific community.


Subject(s)
Aryldialkylphosphatase/genetics , Escherichia coli/genetics , Organophosphorus Compounds/analysis , Pesticides/analysis , Recombinant Proteins/genetics , Aryldialkylphosphatase/metabolism , Biosensing Techniques/methods , Escherichia coli/metabolism , Methyl Parathion/analysis , Recombinant Proteins/metabolism
6.
ACS Appl Bio Mater ; 4(7): 5627-5637, 2021 07 19.
Article in English | MEDLINE | ID: mdl-35006730

ABSTRACT

The path to the discovery of anticancer drugs and investigating their potential activity has remained a quest for several decades. Suberoylanilide hydroxamic acid (SAHA), also known as "Vorinostat", is a well-known histone deacetylase inhibitor (HDACi) and has the potential to act as a therapeutic agent against tumorigenesis. Herein, we have fabricated SAHA incorporated into biocompatible and biodegradable poly(d,l-lactide-co-glycolide) PLGA nanoparticles (NPs) using a facile method of ultrasonic atomization and evaluated their anticancer property. We have explored their characteristics using dynamic light scattering (DLS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), encapsulation efficiency, and in vitro drug release and have investigated their efficacy on U87 glioblastoma (GBM) cells. SAHA-PLGA NPs synthesized were of average mean size of 80 ± 23 and 105 ± 6.0 nm observed through cryo-field-emission gun SEM and HR-TEM with a polydispersity index of 0.068 and a ζ-potential value of -13.26 mV. The encapsulation efficiency was 53%, with a sustained in vitro release up to 48 h. The in vitro assessment of SAHA-PLGA NPs for their anticancer activity on U87 GBM cells showed cellular cytotoxicity with an IC50 of 19.91 µM. SAHA-PLGA NP-treated cells also showed suppression in migration with 8.77 µM concentration, and cell growth inhibition was observed in the wound scratch assay for up to 24 h. The cellular uptake studies have been utilized by time-dependent experiments, revealing their cellular internalization. Taking this into account, our present experimental findings indicate that SAHA-PLGA NPs could play a significant role in enhancing the effectiveness and bioavailability and reducing adverse effects of cancer chemotherapy. It also highlights the inherent potential of these biocompatible entities for chemotherapeutic applications in biomedical and pharmaceutics.


Subject(s)
Brain Neoplasms , Glioblastoma , Brain Neoplasms/drug therapy , Glioblastoma/drug therapy , Humans , Nebulizers and Vaporizers , Polylactic Acid-Polyglycolic Acid Copolymer , Ultrasonics , Vorinostat/pharmacology
7.
Appl Microbiol Biotechnol ; 105(1): 389-400, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33191461

ABSTRACT

Indiscriminate use of organophosphorus (OP)-based insecticides is a great concern to human health because of bioaccumulation-induced health hazards. Potentially fatal consequences and limited treatment methods of OP poisoning necessitate the need for the development of reliable, selective, cost-effective, and sensitive methods of OP detection. To tackle this issue, the development of effective devices and methods is required to sensitively detect as well as degrade OPs. Enzymatic sensor systems have gained popularity due to high catalytic activity, enhanced detection limits, and high sensitivity with the environmentally benign operation. Organophosphorus acid anhydrolase (OPAA) from Alteromonas sp. JD6.5 is capable of hydrolyzing the P-F, P-O, P-S, and P-CN bonds, in OPs, including nerve agents of the G/V-series. Several mutants of OPAA are reported which have greater activity against various OPs. In this study, recombinant expression of the OPAA-FL variant in Escherichia coli was performed, purified, and subsequently tested for activity against ethyl paraoxon. OPAA-FL variant showed its optimum activity at pH 8.5 and 50 °C. Colorimetric and fluorometric assays were used for estimation of ethyl paraoxon based on p-nitrophenol and fluorescein isothiocyanate (FITC) fluorescence intensity, respectively. Colorimetric and fluorometric assay estimation indicates that ethyl paraoxon can be estimated in the linear range of 0.01 to 1 mM and 0.1 to 0.5 mM, with LOD values 0.04 mM and 0.056 mM, respectively. Furthermore, the OPAA-FL variant was immobilized into alginate microspheres for colorimetric detection of ethyl paraoxon and displayed a linear range of 0.025 to 1 mM with a LOD value of 0.06 mM. KEY POINTS: • Biosensing of paraoxon with purified and encapsulated OPAA-FL variant. • Colorimetric and fluorometric biosensing assay developed using OPAA-FL variant for paraoxon. • First report on alginate encapsulation of OPAA-FL variant for biosensing of paraoxon. Graphical abstract.


Subject(s)
Alteromonas , Biosensing Techniques , Pesticides , Aryldialkylphosphatase/genetics , Colorimetry , Organophosphorus Compounds , Paraoxon , Pesticides/analysis
8.
J Genet Eng Biotechnol ; 18(1): 40, 2020 Aug 10.
Article in English | MEDLINE | ID: mdl-32776183

ABSTRACT

BACKGROUND: Tricholepis roylei Hook. f. is a bushy annual shrub of the Asteraceae family and point endemic species of the Western Himalaya. T. roylei is a critically endangered species and factors like poor seed germination and habitat destruction are further rendering the species towards extinction. Therefore, the present investigation was designed to document the seed germination potential of the species and to establish a reproducible in vitro propagation and mass multiplication protocol for the ex situ conservation of T. roylei germplasm. RESULTS: Seeds of T. roylei were collected from Sangdha, Himachal Pradesh, India, and were sown in different substrates under open and controlled conditions. Though the overall seed germination potential of the species was reported to be very low and maximum 45% germination was observed in cocopeat substrate after 26 days of incubation. Half-strength Murashige and Skoog (MS) medium enriched with 6-benzylaminopurine (4.4 µM l-1) and naphthalene acetic acid (1.0 µM l-1) was observed to be the optimum medium for shoot induction in shoot tip explants of T. roylei. Maximum 98.89% shoot formation was observed with 28.42 shoots per culture and 4.4-cm shoot length, respectively. The healthy shoots (4.0 cm) were transferred onto rooting media (1/4, 1/2 and full MS) and roots were developed after 8 weeks of incubation in the half-strength MS medium. Half MS augmented with 4.9 µM l-1 indole butyric acid was observed to be optimum for the root development and an average of 10.2 roots per shoot with 4.0-cm length was obtained. Rooted plantlets were successfully acclimatized under greenhouse conditions and subsequently established in the field, with a recorded survival rate of 90%. The plants acclimatized to the open environment were also planted in the wild under the habitat rehabilitation and species recovery programme. CONCLUSION: The seed germination study envisages that the seed germination potential of the species is very poor and might be one of the probable factors responsible for the shrinkage of T. roylei population in the wild. The standardized micropropagation protocol can be helpful for the ex situ conservation of germplasm and rehabilitation of species in the wild. Moreover, the study could be helpful in elucidating the phytochemical and molecular analysis of species.

9.
Adv Mater ; 32(2): e1905028, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31747097

ABSTRACT

Supersonic cold spraying is an emerging technique for rapid deposition of films of materials including micrometer-size and sub-micrometer metal particles, nanoscale ceramic particles, clays, polymers, hybrid materials composed of polymers and particulates, reduced graphene oxide (rGO), and metal-organic frameworks. In this method, particles are accelerated to a high velocity and then impact a substrate at near ambient temperature, where dissipation of their kinetic energy produces strong adhesion. Here, recent progress in fundamentals and applications of cold spraying is reviewed. High-velocity impact with the substrate results in significant deformation, which not only produces adhesion, but can change the particles' internal structure. Cold-sprayed coatings can also exhibit micro- and nanotextured morphologies not achievable by other means. Suspending micro- or nanoparticles in a liquid and cold-spraying the suspension produces fine atomization and even deposition of materials that could not otherwise be processed. The scalability and low cost of this method and its compatibility with roll-to-roll processing make it promising for many applications, including ultrathin flexible materials, solar cells, touch-screen panels, nanotextured surfaces for enhanced heat transfer, thermal and electrical insulation films, transparent conductive films, materials for energy storage (e.g., Li-ion battery electrodes), heaters, sensors, photoelectrodes for water splitting, water purification membranes, and self-cleaning films.

10.
Sci Rep ; 9(1): 18361, 2019 12 04.
Article in English | MEDLINE | ID: mdl-31797981

ABSTRACT

Malformation of mango inflorescences (MMI) disease causes severe economic losses worldwide. Present research investigates the underlying causes of MMI. Results revealed significantly higher levels of cyanide, a by-product of ethylene biosynthesis, in malformed inflorescences (MI) of mango cultivars. There was a significant rise in ACS transcripts, ACS enzyme activity and cyanide and ethylene levels in MI as compared to healthy inflorescences (HI). Significant differences in levels of methionine, phosphate, S-adenosyl-L-methionine, S-adenosyl-L-homocysteine, ascorbate and glutathione, and activities of dehydroascorbate reductase and glutathione reductase were seen in MI over HI. Further, a lower expression of ß-cyanoalanine synthase (ß-CAS) transcript was associated with decreased cellular ß-CAS activity in MI, indicating accumulation of unmetabolized cyanide. TEM studies showed increased gum-resinosis and necrotic cell organelles, which might be attributed to unmetabolized cyanide. In field trials, increased malformed-necrotic-inflorescence (MNI) by spraying ethrel and decreased MNI by treating with ethylene inhibitors (silver and cobalt ions) further confirmed the involvement of cyanide in MMI. Implying a role for cyanide in MMI at the physiological and molecular level, this study will contribute to better understanding of the etiology of mango inflorescence malformation, and also help manipulate mango varieties genetically for resistance to malformation.


Subject(s)
Amino Acid Oxidoreductases/genetics , Lyases/genetics , Mangifera/genetics , Plant Diseases/genetics , Cyanides/metabolism , Ethylenes/metabolism , Fusarium/genetics , Fusarium/pathogenicity , Gene Expression Regulation, Plant , Inactivation, Metabolic/genetics , Inflorescence/growth & development , Inflorescence/microbiology , Mangifera/growth & development , Mangifera/microbiology , Methionine/metabolism , Phosphates/metabolism , Plant Diseases/microbiology , S-Adenosylmethionine/metabolism
11.
Mol Cell Biochem ; 461(1-2): 23-36, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31309409

ABSTRACT

Antibiotics are the front-line treatment against many bacterial infectious diseases in human. The excessive and long-term use of antibiotics in human cause several side effects. It is important to understand the underlying molecular mechanisms of action of antibiotics in the host cell to avoid the side effects due to the prevalent uses. In the current study, we investigated the crosstalk between mitochondria and lysosomes in the presence of widely used antibiotics: erythromycin (ERM) and clindamycin (CLDM), which target the 50S subunit of bacterial ribosomes. We report here that both ERM and CLDM induced caspase activation and cell death in several different human cell lines. The activity of the mitochondrial respiratory chain was compromised in the presence of ERM and CLDM leading to bioenergetic crisis and generation of reactive oxygen species. Antibiotics treatment impaired autophagy flux and lysosome numbers, resulting in decreased removal of damaged mitochondria through mitophagy, hence accumulation of defective mitochondria. We further show that over-expression of transcription factor EB (TFEB) increased the lysosome number, restored mitochondrial function and rescued ERM- and CLDM-induced cell death. These studies indicate that antibiotics alter mitochondria and lysosome interactions leading to apoptotsis and may develop a novel approach for targeting inter-organelle crosstalk to limit deleterious antibiotic-induced side effects.


Subject(s)
Apoptosis/drug effects , Clindamycin/pharmacology , Erythromycin/pharmacology , Lysosomes/metabolism , Mitochondria/metabolism , Organelle Biogenesis , Anti-Bacterial Agents/pharmacology , Autophagosomes/drug effects , Autophagosomes/metabolism , Autophagy/drug effects , Cell Line , Humans , Lysosomes/drug effects , Membrane Fusion/drug effects , Mitochondria/drug effects , Mitophagy/drug effects , Models, Biological , Reactive Oxygen Species/metabolism , Ribosome Subunits, Large, Bacterial/metabolism
12.
Sci Rep ; 9(1): 5029, 2019 03 22.
Article in English | MEDLINE | ID: mdl-30903010

ABSTRACT

Near infrared (NIR) fluorophores like Pt-porphyrin along with analyte specific enzymes require co-encapsulation in biocompatible and biodegradable carriers in order to be transformed into implantable biosensors for efficient and continuous monitoring of analytes in patients. The main objective of this research is to develop natural, biodegradable, biocompatible and a novel co-encapsulated system of Pt-porphyrin encapsulated polymeric nanoparticle and nano-micro hybrid carriers. A sequential emulsification-solvent evaporation and an air driven atomization technique was used for developing above matrices and testing them for fluorescence based oxygen and glucose biosensing. The results indicate Pt-porphyrin can be efficiently encapsulated in Poly-lactic acid (PLA) nanoparticles and PLA-alginate nano-micro particles with sizes ~450 nm and 10 µm, respectively. Biosensing studies have showed a linear fluorescent response in oxygen concentrations ranging from of 0-6 mM (R2 = 0.992). The Oxygen sensitivity was transformed into a linear response of glucose catalytic reaction in the range of 0-10 mM (R2 = 0.968) with a response time of 4 minutes and a stability over 15 days. We believe that the investigated NIR fluorophores like Pt-Porphyrin based nano/nano-micro hybrid carrier systems are novel means of developing biocompatible biodegradable carriers for developing implantable glucose biosensors which can efficiently manage glucose levels in diabetes.


Subject(s)
Biosensing Techniques/methods , Glucose/chemistry , Nanoparticles/chemistry , Oxygen/chemistry , Platinum/chemistry , Polymers/chemistry , Porphyrins/chemistry , Animals , Biocompatible Materials/chemistry , Biocompatible Materials/metabolism , Biocompatible Materials/pharmacology , Biosensing Techniques/instrumentation , Cell Line , Cell Survival/drug effects , Drug Carriers/chemistry , Drug Compounding , Fluorescent Dyes/chemistry , Fluorescent Dyes/metabolism , Glucose/metabolism , Humans , Mice , Microscopy, Electron , Nanoparticles/ultrastructure , Oxygen/metabolism , Particle Size , Polyesters/chemistry , Polymers/metabolism , Spectrometry, Fluorescence
13.
Nanoscale ; 10(20): 9720-9728, 2018 May 24.
Article in English | MEDLINE | ID: mdl-29762621

ABSTRACT

Charge recombination in CuO photocathodes inhibits efficient electron flow and limits the photo-electrochemical performance of these cathodes for solar water splitting. To circumvent this shortcoming, we introduce highly conductive Ni/CuO core-shell structured fibers. The photocurrent density (PCD) achieved with these core-shell fibers exceeded that of fibers without a Ni core by a factor of 2.6. The PCD enhancement arises from increased acceptor concentration and electron-hole recombination time, as measured by electrochemical impedance spectroscopy. These core-shell nanofibers were fabricated via electrospinning and electroplating. First, a polyacrylonitrile fiber was electrospun and then seeded with metal via sputtering. Second, electroplating was used to encase and metalize the fiber with Ni and Cu. Finally, the outermost Cu shell was oxidized to CuO, which is an effective photocathode for solar water splitting. The Ni-CuO, core-shell layers were characterized by scanning electron microscopy, elemental mapping, X-ray diffraction, and X-ray photoelectron spectroscopy. The core Ni content and number of core-shell fibers per area were optimized through parametric studies.

14.
ACS Appl Mater Interfaces ; 8(14): 9446-53, 2016 Apr 13.
Article in English | MEDLINE | ID: mdl-26999581

ABSTRACT

Here, we demonstrate the production of electrospun SnO(x)-ZnO polyacrylonitrile (PAN) nanofibers (NFs) that are flexible, freestanding, and binder-free. This NF fabric is flexible and thus can be readily tailored into a coin for further cell fabrication. These properties allow volume expansion of the oxide materials and provide shortened diffusion pathways for Li ions than those achieved using the nanoparticle approach. Amorphous SnO(x)-ZnO particles were uniformly dispersed in the carbon NF (CNF). The SnO(x)-ZnO CNFs with a Sn:Zn ratio of 3:1 exhibited a superior reversible capacity of 963 mA·h·g(-1) after 55 cycles at a current density of 100 mA·g(-1), which is three times higher than the capacity of graphite-based anodes. The amorphous NFs facilitated Li2O decomposition, thereby enhancing the reversible capacity. ZnO prevented the aggregation of Sn, which, in turn, conferred stable and high discharge capacity to the cell. Overall, the SnO(x)-ZnO CNFs were shown to exhibit remarkably high capacity retention and high reversible and rate capacities as Li ion battery anodes.

15.
Chemphyschem ; 16(16): 3450-7, 2015 Nov 16.
Article in English | MEDLINE | ID: mdl-26332269

ABSTRACT

We fabricated films of cubic indium oxide (In2O3) by chemical bath deposition (CBD) for solar water splitting. The fabricated films were characterized by X-ray diffraction analysis, Raman scattering, X-ray photoelectron spectroscopy, and scanning electron microscopy, and the three-dimensional microstructure of the In2O3 cubes was elucidated. The CBD deposition time was varied, to study its effect on the growth of the In2O3 microcubes. The optimal deposition time was determined to be 24 h, and the corresponding film exhibited a photocurrent density of 0.55 mA cm(-2). Finally, the film stability was tested by illuminating the films with light from an AM 1.5 filter with an intensity of 100 mW cm(-2).

16.
ACS Appl Mater Interfaces ; 7(38): 21619-25, 2015 Sep 30.
Article in English | MEDLINE | ID: mdl-26340310

ABSTRACT

A Cu(InGa)Se2 film was modified with CdS/ZnO for application to solar water splitting. Platinum was electrodeposited on the ZnO layer as a hydrogen evolution catalyst. The effects of the electroplating time and acidity level of the electrolyte on the photocurrent density were studied. The highest photocurrent density of -32.5 mA/cm(2) under 1.5 AM illumination was achieved with an electroplating time of 30 min at a pH of 9. This photocurrent density is higher than those reported in previous studies. The markedly high performance of the CIGS/CdS/ZnO photocathode was rationalized in terms of its type II cascade structure that facilitated efficient charge separation at the interface junction.

17.
J Int Oral Health ; 6(5): 36-41, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25395791

ABSTRACT

BACKGROUND: Skeletal maturation is an integral part of individual pattern of growth and development and is a continuous process. Peak growth velocity in standing height is the most valid representation of the rate of overall skeletal growth. Ossification changes of hand wrist and cervical vertebrae are the reliable indicators of growth status of individual. The objective of this study was to compare skeletal maturation as measured by hand wrist bone analysis and cervical vertebral analysis. MATERIALS AND METHODS: Hand wrist radiographs and lateral cephalograms of 72 subjects aged between 7 and 16 years both male and female from the patients visiting Department of Orthodontics and Dentofacial Orthopedics, R.V. Dental College and Hospital. The 9 stages were reduced to 5 stages to compare with cervical vertebral maturation stage by Baccetti et al. The Bjork, Grave and Brown stages were reduced to six intervals to compare with cervical vertebral maturational index (CVMI) staging by Hassel and Farman. These measurements were then compared with the hand wrist bone analysis, and the results were statistically analyzed using the Mann-Whitney test. RESULTS: There was no significant difference between the hand wrist analysis and the two different cervical vertebral analyses for assessing skeletal maturation. There was no significant difference between the two cervical vertebral analyses, but the CVMI method, which is visual method is less time consuming. CONCLUSION: Vertebral analysis on a lateral cephalogram is as valid as the hand wrist bone analysis with the advantage of reducing the radiation exposure of growing subjects.

18.
ACS Appl Mater Interfaces ; 5(4): 1232-9, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23347600

ABSTRACT

Electrospinning is a simple and highly versatile method for the large-scale fabrication of polymeric nanofibers. Additives or fillers can also be used to functionalize the nanofibers for use in specific applications. Herein, we demonstrate a novel and efficient way to fabricate superhydrophobic to hydrophilic tunable mats with the combined use of electrospinning and electrospraying that may be suitable for mass production on the merits of rapid deposition. The tunable nanocomposite mats were comprised of hydrophobic polystyrene nanofibers and hydrophilic titania nanoparticles. When the electrical conductivity of the electrospinning solution was increased, the surface morphology of the mats changed noticeably from a bead-on-string structure to an almost bead-free structure. Polystyrene (PS)-titania nanocomposite mats initially yielded a static water contact angle as high as 140° ± 3°. Subsequently exposing these mats with relatively weak ultraviolet irradiation (λ = 365 nm, I = 0.6 mW/cm²) for 2 h, the unique 3D suspension of the photoactive titania nanoparticles maximized the hydrophilic performance of the mats, reducing the static water contact angle to as low as 26° ± 2°. The tunable mats were characterized by scanning electron microscopy (SEM), static water contact angle (WCA) measurements, and energy-dispersive X-ray spectroscopy (EDX). Our findings confirmed that the tunable mats fabricated by the simultaneous implementation of electrospraying and electrospinning had the most efficient ultraviolet (UV)-driven wettability control in terms of cost-effectiveness. Well-controlled tunable hydrophobic and hydrophilic mats find potential applications in functional textiles, environmental membranes, biological sensors, scaffolds, and transport media.


Subject(s)
Metal Nanoparticles , Nanofibers , Polystyrenes/chemistry , Titanium/chemistry , Wettability , Spectrometry, X-Ray Emission , Ultraviolet Rays
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