Single-crystalline, wormlike hematite photoanodes for efficient solar water splitting

A hematite photoanode showing a stable, record-breaking performance of 4.32 mA/cm(2) photoelectrochemical water oxidation current at 1.23 V vs. RHE under simulated 1-sun (100 mW/cm(2)) irradiation is reported. This photocurrent corresponds to ca. 34% of the maximum theoretical limit expected for hematite with a band gap of 2.1 V. The photoanode produced stoichiometric hydrogen and oxygen gases in amounts close to the expected values from the photocurrent. The hematitle has a unique single-crystalline "wormlike" morphology produced by in-situ two-step annealing at 550 degrees C and 800 degrees C of beta-FeOOH nanorods grown directly on a transparent conducting oxide glass via an all-solution method. In addition, it is modified by platinum doping to improve the charge transfer characteristics of hematite and an oxygen-evolving co-catalyst on the surface.open2

Gene Expression of the Tumour Suppressor LKB1 Is Mediated by Sp1, NF-Y and FOXO Transcription Factors

The serine/threonine kinase LKB1 is a tumour suppressor that regulates multiple biological pathways, including cell cycle control, cell polarity and energy metabolism by direct phosphorylation of 14 different AMP-activated protein kinase (AMPK) family members. Although many downstream targets have been described, the regulation of LKB1 gene expression is still poorly understood. In this study, we performed a functional analysis of the human LKB1 upstream regulatory region. We used 200 base pair deletion constructs of the 5′-flanking region fused to a luciferase reporter to identify the core promoter. It encompasses nucleotides −345 to +52 relative to the transcription start site and coincides with a DNase I hypersensitive site. Based on extensive deletion and substitution mutant analysis of the LKB1 promoter, we identified four cis-acting elements which are critical for transcriptional activation. Using electrophoretic mobility shift assays as well as chromatin immunoprecipitations, we demonstrate that the transcription factors Sp1, NF-Y and two forkhead box O (FOXO) family members FOXO3 and FOXO4 bind to these elements. Overexpression of these factors significantly increased the LKB1 promoter activity. Conversely, small interfering RNAs directed against NF-Y alpha and the two FOXO proteins greatly reduced endogenous LKB1 expression and phosphorylation of LKB1's main substrate AMPK in three different cell lines. Taken together, these results demonstrate that Sp1, NF-Y and FOXO transcription factors are involved in the regulation of LKB1 transcription

OPTICAL DLTS MEASUREMENTS OF LOCALIZED STATES IN AMORPHOUS CHALCOGENIDE SEMICONDUCTORS

New combined optical/thermal method (optical DLTS) for the investigation of gap states is presented. The concentration and energy distribution of the gap states have been studied. The optical DLTS signal S(T) vs. temperature is calculated from the photoconductivity decay I(t,T). The effective levels and density of states for amorphous Se and As2Se3 films were obtained

PHOTO-INDUCED MICROCRYSTALLINE Inx(Si0.1Se0,9)1-x FILM-ITO SOLAR CELL

Ce papier décrit les propriétés électriques et optiques des couches Inx(Si0,1Se0,9)1-x et l'effet photovoltaïque de la structure ITO-Inx(Si0,1Se0,9)1-x - Au (0 ≤ x ≤ 0,5). Les couches photoinduites microcristallines In0,1(Si0,1Se0,9)0,9 déposées sur des supports ITO obtenus soit par évaporation soit par pulvérisation ont été examinées par microscopie électronique à balayage. Dans le cas d'ITO pulvérisés, la vitesse de cristallisation était plus grande et le rayon de la zone cristallisée plus petit que pour les ITO évaporés. La réponse spectrale du système avec x = 0,1 après recuit optique a mis en évidence une amélioration remarquable de la phototension de 3000 à 7000 Å et le rendement de conversion a atteint 3,53 % (12 mW/cm2)This paper describes the electrical and optical properties of Inx(Si0.1Se0.9)1-x films, and the photovoltaic effect for ITO - Inx(Si0.1Se0.9)1-x - Au structure (0 ≤ x ≤ 0.5). The photo-induced microcrystalline In0.1(Si0.1Se0,9)0,9 films deposited on both the evaporated and the sputtered ITO layers were examined by scanning electron microscopy (SEM). For the case of the sputtered ITO, the crystallization velocity was greater and the radius of the crystallized region was smaller than that for the evaporated ITO. The spectral response of the system with x = 0.1 after the optical annealing showed the remarkable enhancement of the photovoltage from 3000 to 7000 Å and the conversion efficiency reached 3.53 % (12 mW/cm2)

A PHOTO-INDUCED MEMORY EFFECT OBSERVED ON In-Si-Se SYSTEM

Un effet mémoire photo-induit (phénomène similaire à la photoconductivité persistante) a été trouvé dans des couches polycristallines photo-induites du système In-Si-Se. Le processus polycristallin photo-induit a été obtenu en irradiant l'échantillon (intensité lumineuse de 6 mW/cm2) à 70°C. La conductivité augmente fortement après irradiation par lumière pulsée (intensité de 20 µW/cm2) à basse température (153 K) et un effet mémoire apparaît. En augmentant la température au-dessus d'un point critique (T=263 K), la conductivité revient à sa valeur première. Comme l'effet mémoire photo-induit est reproductible, il peut être considéré comme un phénomène électrique et paraît s'expliquer par un modèle de barrière tenant compte des inhomogénéités diverses des couches polycristallines.A photo-induced memory effect (a phenomenon similar to the persistent photoconductivity) was found in the photo-induced polycrystalline films of the In-Si-Se system. The photo-induced polycrystalline process was performed by irradiating the specimen (the light intensity is 6 mW/cm2) at temperature 70°C. The conductivity drastically increased by irradiation of the light pulse (its intensity is 20 µW/cm2) at low temperature (153 K) and entered a memory state. With increasing the temperature above a critical point (T=263 K), the conductivity returned to the original value. As the photo-induced memory effect is a reproducible phenomenon, it may be considered as an electronic effect and seems to be explained by the barrier model with various inhomogeneities in the polycrystalline films

INITIAL CHECKOUT RESULTS OF THE COMPACT INFRARED CAMERA (CIRC) FOR EARTH OBSERVATION

Compact Infrared Camera (CIRC) is a technology-demonstration instrument equipped with an uncooled infrared array detector (microbolometer) for space application. CIRC is the first microbolometer sensor without a calibration function in orbit, like a shutter system or an onboard blackbody. The main objective of the CIRC is to detect wildfires, which are major and chronic disasters affecting various countries of Southeast Asia, particularly considering the effects of global warming and climate change. The CIRC achieves a small size (approximately 200 mm), light mass (approximately 3 kg), and low electrical power consumption (<20 W) by employing athermal optics and a shutterless system. The CIRC can be consequently mounted on multiple satellites to enable highfrequency observation. Installation of CIRCs on the ALOS-2 and on the JEM/CALET is expected to increase observation frequency. We present the initial check-out results of the CIRC onboard ALOS-2. Since the initial check-out phase (July 4&ndash;14, 2014), the CIRC has acquired the images of Earth. CIRC was demonstrated to function according to its intended design. After the early calibration validation phase, which confirmed the temperature accuracy of observed data, CIRC data has been available to the public January 2015 onward. We also introduce a few observational results about wildfire, volcanoes, and heat-island

Cleavage of Peptides from Amphibian Skin Revealed by Combining Analysis of Gland Secretion and in Situ MALDI Imaging Mass Spectrometry

Peptides from skin secretions of amphibians are considered important components of their immune system and also play a relevant role in their defense mechanism against predators. Herein, by using mass spectrometry (MS), we characterize the sequence of 13 peptides from the gland secretion of the hylid tree frog, Boana punctata. Using in situ matrix-assisted laser desorption ionization imaging MS of a transverse section of the skin tissue, we show that some peptides are stored as longer molecules that are cleaved after being secreted, whereas others do not undergo any modification. Sequence comparison with peptides from other Boana species and analysis of the three-dimensional theoretical structure indicate that this cleavage depends on both the presence of a specific sequence motif and the secondary structure. The fact that peptides undergo a rapid cleavage upon secretion suggests that stored and secreted peptides may have distinct roles for anuran survival, including defense against pathogens and predators.Fil: Brunetti, Andrés Eduardo. Universidade de Sao Paulo; Brasil. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Marani, Mariela Mirta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Soldi, Rafael A.. Universidade de Sao Paulo; BrasilFil: Mendonça, Jacqueline Nakau. Universidade de Sao Paulo; BrasilFil: Faivovich, Julián. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Cabrera, Gabriela Myriam. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Lopes, Norberto P.. Universidade de Sao Paulo; Brasi