Pick-up and assembling of chemically sensitive van der Waals heterostructures using dry cryogenic exfoliation.

Assembling atomic layers of van der Waals materials (vdW) combines the physics of two materials, offering opportunities for novel functional devices. Realization of this has been possible because of advancements in nanofabrication processes which often involve chemical processing of the materials under study; this can be detrimental to device performance. To address this issue, we have developed a modified micro-manipulator setup for cryogenic exfoliation, pick up, and transfer of vdW materials to assemble heterostructures. We use the glass transition of a polymer PDMS to cleave a flake into two, followed by its pick-up and drop to form pristine twisted junctions. To demonstrate the potential of the technique, we fabricated twisted heterostructure of Bi2Sr2CaCu2O8+x (BSCCO), a van der Waals high-temperature cuprate superconductor. We also employed this method to re-exfoliate NbSe2 and make twisted heterostructure. Transport measurements of the fabricated devices indicate the high quality of the artificial twisted interface. In addition, we extend this cryogenic exfoliation method for other vdW materials, offering an effective way of assembling heterostructures and twisted junctions with pristine interfaces.

Community Pharmacist's Awareness, Knowledge and Attitude Towards use of Vitamin Supplements in Pimpri-Chinchwad Municipal Corporation (PCMC) Area of Pune, India: A Descriptive Cross Sectional Study.

Background: US FDA defines: dietary supplements is a product that intended to supplement a person's diet, it's generally consist of at least one or more of the following dietary ingredients, vitamin, minerals, a herb or other botanical and amino acid by increasing the daily consumptions of an extract metabolite concentration, constitute or combinations of these medication. Excessive and inappropriate use of medicines has been recognised as a public health problem resulting in increased likelihood of adverse drug event, drug interaction, and inappropriate drug prescribing and increased cost. Material and Methods: This was the cross-sectional study conducted in year 2022 at Pimpri Chinchwad (Pune). The total 250 questionaires are distributed and from that 226 response were received. Target population consist of community pharmacists working in the drug store in this area (n=226). Results: Data was represented in three domains of study i. e. awareness, knowledge and attitude. Correlation coefficient using Pearson's method were determined to evaluate strength of correlation between awareness-knowledge, Knowledge-attitude and awareness-attitude. Correlation coefficient were calculated by comparing most relevant and equal number of questions. Conclusion: The study demonstrated positive attitude among surveyed community pharmacists in Pune, India. There is lacuna in accurate and adequate awareness, knowledge and attitude of vitamin deficiency, efficiency, recommended daily allowance (RDA), toxicity and interactions among pharmacist as one of the stakeholders of healthcare in India. Few of the remedies viz. framing of guidelines, inclusion in formal education syllabus, continuous education, updation exams etc. may be of use.

Multilayer WS2 for low-power visible and near-infrared phototransistors.

Mechanically exfoliated multilayer WS2 flakes are used as the channel of field effect transistors for low-power photodetection in the visible and near-infrared (NIR) spectral range. The electrical characterization as a function of the temperature reveals devices with n-type conduction and slightly different Schottky barriers at the drain and source contacts. The WS2 phototransistors can be operated in self-powered mode, yielding both a current and a voltage when exposed to light. The spectral photoresponse in the visible and the NIR ranges shows a high responsivity (4.5 µA/W) around 1250 nm, making the devices promising for telecommunication applications.

High-temperature Josephson diode.

Many superconducting systems with broken time-reversal and inversion symmetry show a superconducting diode effect, a non-reciprocal phenomenon analogous to semiconducting p-n-junction diodes. While the superconducting diode effect lays the foundation for realizing ultralow dissipative circuits, Josephson-phenomena-based diode effect (JDE) can enable the realization of protected qubits. The superconducting diode effect and JDE reported thus far are at low temperatures (~4 K), limiting their applications. Here we demonstrate JDE persisting up to 77 K using an artificial Josephson junction of twisted layers of Bi2Sr2CaCu2O8+δ. JDE manifests as an asymmetry in the magnitude and distributions of switching currents, attaining the maximum at 45° twist. The asymmetry is induced by and tunable with a very small magnetic field applied perpendicular to the junction and arises due to interaction between Josephson and Abrikosov vortices. We report a large asymmetry of 60% at 20 K. Our results provide a path towards realizing superconducting Josephson circuits at liquid-nitrogen temperature.

Design and development of donepezil hydrochloride loaded nanostructured lipid carriers for efficient management of Alzheimer's disease.

OBJECTIVE: The primary objective of this study was to develop nanostructured lipid carriers of donepezil hydrochloride (DNZ HCl) for effective management of Alzheimer's disease (AD). SIGNIFICANCE: Intranasal administration of DNZ NLC containing Nigella sativa (NS) oil as a liquid lipid may significantly improve nasal penetration and deliver the drug directly to the brain avoiding blood brain barrier (BBB). METHOD: High pressure homogenization was used to prepare nanostructured lipid carriers (NLCs), followed by ultrasonication. Glyceryl monostearate (GMS), Tween 80, and Poloxamer 407 were used as solid lipid, surfactant and co-surfactant respectively, whereas, Nigella sativa oil was used as a liquid lipid. RESULT: The particle size, polydispersity index and zeta potential were found to be 107.4 ± 2.64 nm, 0.25 ± 0.04 and -41.7 mV. The entrapment efficiency and drug content were found to be 70.20% and 89.05% respectively. After intranasal administration of Donepezil hydrochloride (DNZ HCl) loaded NLC's, the maximum concentrations (Cmax) of 4.597 µg/mL in brain and 2.2583 µg/mL in blood was achieved after 1 h (Tmax). CONCLUSION: The formulated DNZ HCl loaded NLCs significantly improved nasal penetration and enhanced drug distribution in brain resulting in a potentially effective intranasal drug delivery system for the effective management of Alzheimer's disease.

Determination of Acephate, Dinotefuran, and Emamectin Benzoate in a Pesticide Formulation: A Single-Laboratory Validation.

BACKGROUND: The advantage of simultaneous separation and quantification is the reduction of analysis time and consumption of solvents and reagents. OBJECTIVE: The objective of the present investigation was to optimize and validate a novel, rapid, and simple reverse-phase high-performance liquid chromatographic method for the simultaneous determination of acephate, dinotefuran, and emamectin benzoate in a pesticide formulation. METHOD: The chromatographic separation and quantification were accomplished by using Kromasil CN column (250 mm × 4.6 mm; 5 µm) with a mobile phase consisting of acetonitrile and water [0.1% (v/v) triethylamine, pH 2.7 with 10% (v/v) orthophosphoric acid] in the ratio of 50:50 (v/v) with a flow rate of 1.0 mL/min and diode array detection at the wavelength of (215 nm and 245 nm). RESULTS: The HPLC method was able to separate and quantify all the actives in the formulation by isocratic elution within 10 min. The method was fully validated in accordance with the SANCO and Collaborative International Pesticide Analytical Council guidelines concerning system suitability, specificity, linearity, precision, accuracy, and robustness. All the analytical parameters are within the range of acceptable limits in the guidelines. CONCLUSIONS: The validated method was successfully applied to a pesticide formulation. HIGHLIGHTS: The novelty of the current research work lies in the development of the simple and rapid HPLC method for simultaneous determination of acephate, dinotefuran, and emamectin benzoate in wettable granular formulation.

A novel validated simple derivatization liquid chromatographic method with diode array detection for the simultaneous determination of mancozeb, azoxystrobin and difenoconazole in pesticide dosage form.

A novel, rapid and simple reverse-phase high performance liquid chromatography (RP-HPLC) method for the simultaneous determination of three pesticides - mancozeb, azoxystrobin and difenoconazole by derivatization with ethyl iodide is presented. Analysis was performed on a C18 column (Agilent Eclipse plus, 150 mm × 4.6 mm; 5 µ) with the mobile phase consisting of acetonitrile + methanol (90 + 10 v/v) - water (0.1% v/v trifluoroacetic acid) (60 : 40, v/v) pumped isocratically at a flow rate of 1.0 mL min-1 and detection wavelength of 205 nm and 272 nm. The factors affecting the derivatization reaction and separation conditions were carefully evaluated and optimized. The method was linear over the concentration range of 3.50 mg L-1 to 31.48 mg L-1 for mancozeb, 0.32 mg L-1 to 2.85 mg L-1 for azoxystrobin and 0.32 mg L-1 to 2.89 mg L-1 for difenoconazole. The new method was successfully applied for the analysis of mancozeb, azoxystrobin and difenoconazole in the pesticide formulation with range recoveries of 99.46% to 100.76%, 99.07% to 101.09% and 98.59% to 101.59%, respectively. The present method is suitable and favorable for the simultaneous separation and analysis of tertiary mixture analytes on account of its sensitivity, rapidity and cost-effectiveness. In addition, it could have excellent application prospects for the simultaneous determination of all three pesticides in other formulated products.

A simple derivatization RP-HPLC method for the simultaneous determination of zineb and hexaconazole in pesticide formulation using a PDA detector.

A simple derivatization reverse-phase high performance liquid chromatographic method for the simultaneous analysis (separation and quantification) of zineb and hexaconazole has been optimized and validated. The method was carried out on an Agilent Eclipse plus C18 column (150 × 4.6 mm; 5 µm), with a mobile phase comprising acetonitrile + methanol (80 + 20 v/v): water (0.1% v/v trifluoroacetic acid) (60 : 40 v/v) at a flow rate of 1.0 mL minute-1, and the quantification was achieved at 272 nm and 205 nm. The retention times of zineb and hexaconazole were found to be 6.4 min and 7.6 min, respectively. The performance of the method was validated according to the SANCO, CIPAC and ICH guidelines for specificity, selectivity, linearity, precision, accuracy, limit of detection, limit of quantification and robustness. The developed method was successfully applied for the estimation of zineb and hexaconazole in a pesticide dosage form.

Purely Spin-Vibronic Coupling Assisted Triplet to Singlet Up-Conversion for Real Deep Blue Organic Light-Emitting Diodes with Over 20% Efficiency and y Color Coordinate of 0.05.

Finding narrow-band, ultrapure blue thermally activated delayed fluorescence (TADF) materials is extremely important for developing highly efficient organic light-emitting diodes (OLEDs). Here, spin-vibronic coupling (SVC)-assisted ultrapure blue emitters obtained by joining two carbazole-derived moieties at a para position of a phenyl unit and performing substitutions using several blocking groups are presented. Despite a relatively large singlet-triplet gap (∆EST ) of >0.2 eV, efficient triplet-to-singlet crossover can be realized, with assistance from resonant SVC. To enhance the spin crossover, electronic energy levels are fine-tuned, thereby causing ∆EST to be in resonance with a triplet-triplet gap (∆ETT ). A sizable population transfer between spin multiplicities (>103 s-1 ) is achieved, and this result agrees well with theoretical predictions. An OLED fabricated using a multiple-resonance-type SVC-TADF emitter with CIE color coordinates of (0.15, 0.05) exhibits ultrapure blue emissions, with a narrow full-width-at-half-maximum of 21 nm and a high external quantum efficiency of 23.1%.

High mobility field-effect transistors based on MoS2crystals grown by the flux method.

Two-dimensional (2D) molybdenum disulphide (MoS2) transition metal dichalcogenides (TMDs) have great potential for use in optical and electronic device applications; however, the performance of MoS2is limited by its crystal quality, which serves as a measure of the defects and grain boundaries in the grown material. Therefore, the high-quality growth of MoS2crystals continues to be a critical issue. In this context, we propose the formation of high-quality MoS2crystals via the flux method. The resulting electrical properties demonstrate the significant impact of crystal morphology on the performance of MoS2field-effect transistors. MoS2made with a relatively higher concentration of sulphur (a molar ratio of 2.2) and at a cooling rate of 2.5 °C h-1yielded good quality and optimally sized crystals. The room-temperature and low-temperature (77 K) electrical transport properties of MoS2field-effect transistors (FETs) were studied in detail, with and without the use of a hexagonal boron nitride (h-BN) dielectric to address the mobility degradation issue due to scattering at the SiO2/2D material interface. A maximum field-effect mobility of 113 cm2V-1s-1was achieved at 77 K for the MoS2/h-BN FET following high-quality crystal formation by the flux method. Our results confirm the achievement of large-scale high-quality crystal growth with reduced defect density using the flux method and are key to achieving higher mobility in MoS2FET devices in parallel with commercially accessible MoS2crystals.

Strategic Synchronization of 7,7-Dimethyl-5,7-dihydroindeno[2,1-b]carbazole for Narrow-Band, Pure Violet Organic Light-Emitting Diodes with an Efficiency of > 5% and a CIE y Coordinate of < 0.03.

A novel violet emitter, 1,3-bis[10,10-dimethyl-10H-indeno[2,1-b]]indolo[3,2,1-jk]indolo[1',2',3':1,7]indolo[3,2-b]carbazole (m-FLDID), was designed and synthesized by meta-oriented bis-fusion of two 7,7-dimethyl-5,7-dihydroindeno[2,1-b]carbazole (DMID) subunits for use in a pure violet organic light-emitting diode (OLED). Incorporation of the DMID subunits effectively reduced the nonradiative recombination rate, improving the photoluminescence quantum yield of the m-FLDID emitter. The meta-oriented bis-fusion of the two DMID subunits not only triggered an alternative distribution of the frontier orbitals but also effectively locked the π-conjugation chain, which ultimately resulted in a narrow-band, pure violet emission of the m-FLDID emitter. Doped m-FLDID devices possessed an external quantum efficiency (EQE) of > 5%, pure violet emission with a maximum at 407 nm, a narrow full width at half-maximum of 17 nm, and a Commission Internationale de l'éclairage y coordinate of less than 0.03. This is the first work reporting an EQE of > 5% and an extremely narrow emission spectrum for a pure violet emitter.

m-CPBA Mediated Metal Free, Rapid Oxidation of Aliphatic Amines to Oximes.

An efficient, rapid oxidation of various aliphatic amines to oximes using m-CPBA as an oxidant in ethyl acetate is described. High conversion (100%) with >90% oxime selectivity is achieved at room temperature under catalyst-free conditions. Mild reaction conditions along with an easy work up procedure offer lower byproduct formation and high selectivity for oximes in good yield and purity.

Steric-Hindrance-Induced Regio- and Chemoselective Oxidation of Aromatic Amines.

Unusual regio- and chemoselective oxidation of aromatic amines hindered with ortho substituents (except -NH2, -NHCH3, and -OH) to the corresponding nitro compounds is described by use of nonanebis(peroxoic acid). The mechanistic investigation for selective oxidation of amines ortho-substituted with -NH2 or -OH showed the involvement of H-bonding between the ortho hydrogen of the adjacent -XH group (where X = NH, NR, or O) and an oxygen atom from the diperoxy acid. Various mono- and diamines are oxidized into corresponding mononitro derivatives in high yield and purity without employing any protection strategies. The protocol was also found to successful on the gram scale.

Nonanebis(peroxoic acid): a stable peracid for oxidative bromination of aminoanthracene-9,10-dione.

A new protocol for the oxidative bromination of aminoanthracene-9,10-dione, which is highly deactivated towards the electrophilic substitution is investigated. The peracid, nonanebis(peroxoic acid), possesses advantages such as better stability at room temperature, it is easy to prepare and non-shock sensitiv as compared to the conventional peracids. The present protocol has a broad scope for the bromination of various substituted and unsubstituted aminoanthracene-9,10-diones.