Zinc oxide-nickel cermet selective coatings obtained by sequential electrodeposition

The investigation of pulse electrodepositing modes influence on crystal structure, morphology and optical properties of ZnO has revealed the conditions in which quasi-one-dimensional (1D) ZnO nanorod arrays are formed as separate nanorods. Due to a sufficiently high resistance of zinc oxide, the electrodeposition of nickel on the fluorine doped tin oxide (FTO)/ZnO surfaces carried out in space between the ZnO nanorods. An incomplete filling of the gaps between nanorods by the nickel nanoparticles through subsequent Ni electrodeposition ensured the creation of ZnO–Ni graded cermets. The cermets, in which electrochemical filling of the spaces between ZnO nanorods by Ni, was performed in the pulse mode. It provided higher absorption of visible and near IR light. It was shown that the manufactured ZnO–Ni graded cermets have high light absorption combined with comparatively low thermal losses, so these cermets are promising cheap and affordable selective coatings for solar heat collectors

Structure, optical, electrical and thermoelectric properties of solution-processed Li-doped NiO films grown by SILAR

The article presents a new facial synthesis of Li-doped NiO films (NiO:Li) via an easy and cost-effective method Successive Ionic Layer Adsorption and Reaction (SILAR) with the processing of the obtained NiO films in a lithium-containing aqueous solution for their transformation after annealing into NiO:Li layers. Comparative analysis of crystal structure, optical, electrical and thermoelectric properties of the obtained NiO and NiO:Li 420-1050 nm thick films have reveiled a cubic rock-salt NiO structure, at that, NiO:Li samples are nanocrystalline single phased Li-NiO solid solutions. The fabricated NiO and NiO:Li films are p-type semiconductors with activation energy Ea = 0.1 eV and Ea = 0.25‒0.31 eV, respectively. The obtained in-plane Seebeck coefficients Z are in the range 0.20–0.33 mV/К. Notwithstanding the fact that the maximum values of the thermoelectric power factors P=2.2 μW/K2·m, are rather small, they were achieved if the hot end of the NiO:Li film was heated only to 115 °C. Thus, the produced in this work new low cost thermoelectric thin film material is suitable for a production of electrical energy for low-power devices due to absorption of low-potential heat

АНТИОТРАЖАЮЩИЕ ПОКРЫТИЯ ИЗ ЭЛЕКТРООСАЖДЕННЫХ МАССИВОВ ОКСИДА ЦИНКА ДЛЯ СОЛНЕЧНЫХ ЭЛЕМЕНТОВ

Surfaces of current photovoltaic devices are characterized by a high refractive index, so they tend to significant reflection of light. This explains the need for an antireflective coating (AR). In this paper, for the first time we demonstrate the possibility of creating the AR in the form of nano-scale zinc oxide array with a parabolic profile by its pulse electrodeposition from aqueous electrolytes. The study of the influence of the zinc oxide deposition mode on their optical properties such as transparency and reflection in the visible region at different angles of radiation, the optical band gap and Urbach energy were performed using a spectrophotometer SF-2000 equipped with specular and diffuse reflection attachment SFO-2000. Structural characteristics, namely, lattice parameters, microstrains, residual stress and texture were analyzed by X-ray diffractometry. Morphology of the grown arrays was investigated by intermittent-contact atomic force microscopy (AFM) using a NanoLaboratory Ntegra Prima NT-MDT setup. Optimization of the pulse electrodeposition mode allowed to adjust the size of parabolic nipples and thus to create AR moth-eye structure based on the electrodeposited zinc oxide arrays, which is suitable for use in photovoltaic devices. Bibliography. 7, Table. 1, Fig. 5.Поверхности современных фотоэлектрических преобразователей характеризуются довольно высоким коэффициентом преломления, поэтому им свойственно значительное отражение света, для устранения которого прибегают к нанесению антиотражающих покрытий (АП). В данной работе впервые показана возможность создания АП в виде наноразмерных массивов оксида цинка с параболическим профилем методом импульсного электрохимического осаждения из водных электролитов. Исследование влияния режимов осаждения массивов оксида цинка на такие его оптические свойства как прозрачность и отражение в видимой области при различных углах облучения, на оптическую ширину запрещенной зоны и на энергию Урбаха выполняли с помощью спектрофотометра СФ-2000, оснащенного приставкой зеркального и диффузного отражения СФО-2000. Структурные характеристики, а именно, параметры кристаллической решетки, микронапряжения, остаточные напряжения и текстура анализировались по данным рентген-дифрактометрических исследований. Морфологию выращиваемых массивовисследовали полуконтактным методом атомной силовой микроскопии (АСМ) на установке «НаноЛаборатория Нтегра Прима NT-MDT». Оптимизация режимов импульсного электроосаждения позволила скорректировать размеры параболических нановыступов и таким образом обеспечить создание на основе электроосажденных массивов оксида цинка пригодного для использования в фотоэлектрических преобразователях АП с эффектом глаза ночной бабочки. Библ. 7, табл. 1, рис. 5.Поверхні сучасних фотоелектричних перетворювачів характеризуються досить високим коефіцієнтом заломлення, тому їм властиво значне відображення світла, для усунення якого вдаються до нанесення антивідбиваючих покриттів (АП). У даній роботі вперше показана можливість створення АП у вигляді нанорозмірних масивів оксиду цинку з параболічним профілем методом імпульсного електрохімічного осадження з водних електролітів. Дослідження впливу режимів осадження масивів оксиду цинку на такі його оптичні властивості як прозорість і відображення у видимій області при різних кутах опромінення, на оптичну ширину забороненої зони та на енергію Урбаха виконували за допомогою спектрофотометра СФ-2000, оснащеного приставкою дзеркального і дифузного віддзеркалення СФО-2000 . Структурні характеристики, а саме, параметри кристалічної решітки, мікронапруги, залишкові напруги і текстура аналізувалися за даними рентген-дифрактометричних досліджень. Морфологію вирощуваних масивів досліджували напівконтактним методом атомної силової мікроскопії (АСМ) на установці «НаноЛабораторія Нтегра Прима NT-MDT». Оптимізація режимів імпульсного електроосадження дозволила скорегувати розміри параболічних нановиступов і таким чином забезпечити створення на основі електроосадженних масивів оксиду цинку придатного для використання в фотоелектричних перетворювачах АП з ефектом ока нічного метелика. Бібл. 7, табл. 1, мал. 5

Telescoped approach to aryl hydroxymethylation in the synthesis of a key pharmaceutical intermediate

An efficient synthetic approach leading to introduction of the hydroxymethyl group to an aryl moiety via combination of the Bouveault formylation and hydride reduction has been optimized using a rational, mechanistic-based approach. This approach enabled telescoping of the two steps into a single efficient process, readily amenable to scaleup

Mitochondrial ROS control neuronal excitability and cell fate in frontotemporal dementia.

INTRODUCTION: The second most common form of early-onset dementia-frontotemporal dementia (FTD)-is often characterized by the aggregation of the microtubule-associated protein tau. Here we studied the mechanism of tau-induced neuronal dysfunction in neurons with the FTD-related 10+16 MAPT mutation. METHODS: Live imaging, electrophysiology, and redox proteomics were used in 10+16 induced pluripotent stem cell-derived neurons and a model of tau spreading in primary cultures. RESULTS: Overproduction of mitochondrial reactive oxygen species (ROS) in 10+16 neurons alters the trafficking of specific glutamate receptor subunits via redox regulation. Increased surface expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors containing GluA1 and NR2B subunits leads to impaired glutamatergic signaling, calcium overload, and excitotoxicity. Mitochondrial antioxidants restore the altered response and prevent neuronal death. Importantly, extracellular 4R tau induces the same pathological response in healthy neurons, thus proposing a mechanism for disease propagation. DISCUSSION: These results demonstrate mitochondrial ROS modulate glutamatergic signaling in FTD, and suggest a new therapeutic strategy

Solution-processed flexible broadband ZnO photodetector modified by Ag nanoparticles

In this work, we present flexible broadband photodetectors (PDs) fabricated by a deposition of nanostructured zinc oxide (ZnO) films on polyimide (PI) substrates by using cheap and scalable aqueous method Successive Ionic Layer Adsorption and Reaction (SILAR). In order to increase the long-wavelength absorption of the nanostructured ZnO layer, we created its intrinsic defects, including oxygen vacancies by post-treatment at 300 °C in vacuum and thus the light-sensitive material ZnO/PI was obtained. Then we applied silver nanoparticles (Ag NPs) from a silver sol onto a nanostructured ZnO film, which were visualized using SEM in the form of spheres up to 100 nm in size that increased the photocurrent and figures of merit of thus obtained light-sensitive material ZnO_Ag/PI due to localized surface plasmon resonance and double Schottky barriers at the Ag-ZnO interface. To fabricate photodetectors based on a photoconductive effect, these ZnO/PI and ZnO_Ag/PI materials were equipped with ohmic aluminum contacts. The spectral responsivity (Rλ up to 275 A/W to UV light) of solution-processed flexible broadband photodetector based on ZnO_Ag/PI material at different wavelengths of light and light power densities is better than Rλ of the ZnO/PI photodetector, and at least an order of magnitude higher than Rλ of photodetectors based on nanostructured zinc oxide described in recent articles. The external quantum efficiency (EQE) of both PDs in this study in UV–Vis-NIR spectra is very high in the range from 1∙102 to 9∙104 % and is better or of the same order of magnitude as the EQE data of modern flexible broadband high-sensitivity PDs based on nanostructured heterostructures containing ZnO. The specific detectivity in UV–Vis-NIR spectra is large for ZnO/PI (from 3.5∙1010 to 1∙1012 Jones) and especially for ZnO_Ag/PI (from 1.6∙1011 to 8.6∙1013 Jones), which indicates the ability of the PDs based on light-sensitive materials ZnO/PI and ZnO_Ag/PI to recognize a very weak light signal

The History of Flow Chemistry at Eli Lilly and Company

Flow chemistry was initially used for speed to early phase material delivery in the development laboratories, scaling up chemical transformations that we would not or could not scale up batch for safety reasons. Some early examples included a Newman Kwart Rearrangement, Claisen rearrangement, hydroformylation, and thermal imidazole cyclization. Next, flow chemistry was used to enable safe scale up of hazardous chemistries to manufacturing plants. Examples included high pressure hydrogenation, aerobic oxidation, and Grignard formation reactions. More recently, flow chemistry was used in Small Volume Continuous (SVC) processes, where highly potent oncolytic molecules were produced by fully continuous processes at about 10 kg/day including reaction, extraction, distillation, and crystallization, using disposable equipment contained in fume hoods

ЭЛЕКТРООСАЖДЕННЫЕ ПЛЕНОЧНЫЕ КОМПОЗИЦИИ ДЛЯ ПРЕКУРСОРОВ КЕСТЕРИТНЫХ СОЛНЕЧНЫХ ЭЛЕМЕНТОВ

A comparative analysis of structure andsurface morphology of copper, tin, zinc films andfilm stacks madeby electrochemicaldepositionin galvanostaticsteady-state conditions, in galvanostatic modewith ultrasonicagitationof electrolytes,in the forwardpulse andreversepulse modeswith a rectangularpulses has been shown.The influence of themodesof electrodepositionon the structure, optical properties and surface morphology of theamorphous and crystalline selenium films presented.By sequentialelectrochemical deposition the film stacks Cu/Zn/Sn/Se andCu/Sn/Zn/Se were obtained, which are models ofkesterite precursors.Theseprecursorsafter theirconversion intoCu2ZnSnSe4 semiconductorsbysubsequent annealingwill be used asbase layers ofcheap and efficientthin film solar cellsof the new generation.Bibliography.10, Tab. 4, Fig.4.Представлены результаты сравнительного анализа структуры и морфологии поверхности пленок меди, олова, цинка и их слоевых композиций, изготовленных путем электрохимического осаждения в гальваностатическом стационарном режиме, в гальваностатическом режиме с ультразвуковым перемешиванием электролитов, в прямом импульсном и реверсивном импульсном режимах с прямоугольной формой импульсов потенциала. Изучено влияние режимов электроосаждения на структуру, оптические свойства и морфологию поверхности аморфных и кристаллических пленок селена. Путем последовательного электрохимического осаждения изготовлены пленочные композиции Cu/Zn/Sn/Se и Cu/Sn/Zn/Se, являющиеся моделями прекурсоров кестерита. Такие прекурсоры после их преобразования путем последующих отжигов в полупроводниковый материалCu2ZnSnSe4 будут использованы в качестве базовых слоев дешевых и эффективных тонкопленочных солнечных элементов нового поколения. Библ. 10, табл. 4, рис. 4.Представлены результаты сравнительного анализа структуры и морфологии поверхности пленок меди, олова, цинка и их слоевых композиций, изготовленных путем электрохимического осаждения в гальваностатическом стационарном режиме, в гальваностатическом режиме с ультразвуковым перемешиванием электролитов, в прямом импульсном и реверсивном импульсном режимах с прямоугольной формой импульсов потенциала. Изучено влияние режимов электроосаждения на структуру, оптические свойства и морфологию поверхности аморфных и кристаллических пленок селена. Путем последовательного электрохимического осаждения изготовлены пленочные композиции Cu/Zn/Sn/Se и Cu/Sn/Zn/Se, являющиеся моделями прекурсоров кестерита. Такие прекурсоры после их преобразования путем последующих отжигов в полупроводниковый материалCu2ZnSnSe4 будут использованы в качестве базовых слоев дешевых и эффективных тонкопленочных солнечных элементов нового поколения. Библ. 10, табл. 4, рис. 4

Variation of electric shielding on virtual Frisch-grid detectors

Because of the low mobility of holes, CdZnTe (CZT) detectors operate as electron-transport-only type devices whose particular geometrical parameters and contacts configurations are specially chosen to minimize the contribution of uncollected holes into the output signal amplitudes (induction effect). Several detector configurations have been proposed to address this problem. One of them employs a large geometrical aspect ratio, parallelepiped-shaped crystal with two planar contacts on the top and bottom surfaces (anode and cathode) and an additional shielding electrode placed on a crystal\u27s side to create the virtual Frisch-grid effect. We studied the effect of the shielding electrode length, as well as its location, on the responses of 6 x 6 x 15 mm(3) virtual Frisch-grid detectors. We found that the length of the shielding electrode placed next to the anode can be reduced to 5 mm with no adverse effects on the device performance. Meanwhile, this allows for charge loss correction by reading the cathode signal

Protein aggregation and calcium dysregulation are hallmarks of familial Parkinson's disease in midbrain dopaminergic neurons

Mutations in the SNCA gene cause autosomal dominant Parkinson’s disease (PD), with loss of dopaminergic neurons in the substantia nigra, and aggregation of α-synuclein. The sequence of molecular events that proceed from an SNCA mutation during development, to end-stage pathology is unknown. Utilising human-induced pluripotent stem cells (hiPSCs), we resolved the temporal sequence of SNCA-induced pathophysiological events in order to discover early, and likely causative, events. Our small molecule-based protocol generates highly enriched midbrain dopaminergic (mDA) neurons: molecular identity was confirmed using single-cell RNA sequencing and proteomics, and functional identity was established through dopamine synthesis, and measures of electrophysiological activity. At the earliest stage of differentiation, prior to maturation to mDA neurons, we demonstrate the formation of small β-sheet-rich oligomeric aggregates, in SNCA-mutant cultures. Aggregation persists and progresses, ultimately resulting in the accumulation of phosphorylated α-synuclein aggregates. Impaired intracellular calcium signalling, increased basal calcium, and impairments in mitochondrial calcium handling occurred early at day 34–41 post differentiation. Once midbrain identity fully developed, at day 48–62 post differentiation, SNCA-mutant neurons exhibited mitochondrial dysfunction, oxidative stress, lysosomal swelling and increased autophagy. Ultimately these multiple cellular stresses lead to abnormal excitability, altered neuronal activity, and cell death. Our differentiation paradigm generates an efficient model for studying disease mechanisms in PD and highlights that protein misfolding to generate intraneuronal oligomers is one of the earliest critical events driving disease in human neurons, rather than a late-stage hallmark of the disease