bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of triclosan on bacterial community composition and Vibrio populations in natural seawater microcosms
Authors: Lydon Keri Ann , Glinski Donna A. , Westrich Jason R. , Henderson W. Matthew , Lipp Erin K.
Published: May 2017

Pharmaceuticals and personal care products, including antimicrobials, can be found at trace levels in treated wastewater effluent. Impacts of chemical contaminants on coastal aquatic microbial community structure and pathogen abundance are unknown despite the potential for selection through antimicrobial resistance. In particular, Vibrio, a marine bacterial genus that includes several human pathogens, displays resistance to the ubiquitous antimicrobial compound triclosan. Here we demonstrated through use of natural seawater microcosms that triclosan (at a concentration of ~5 ppm) can induce a significant Vibrio growth response (68–1,700 fold increases) in comparison with no treatment controls for three distinct coastal ecosystems: Looe Key Reef (Florida Keys National Marine Sanctuary), Doctors Arm Canal (Big Pine Key, FL), and Clam Bank Landing (North Inlet Estuary, Georgetown, SC). Additionally, microbial community analysis by 16 S rRNA gene sequencing for Looe Key Reef showed distinct changes in microbial community structure with exposure to 5 ppm triclosan, with increases observed in the relative abundance of Vibrionaceae (17-fold), Pseudoalteromonadaceae (65-fold), Alteromonadaceae (108-fold), Colwelliaceae (430-fold), and Oceanospirillaceae (1,494-fold). While the triclosan doses tested were above concentrations typically observed in coastal surface waters, results identify bacterial families that are potentially resistant to triclosan and/or adapted to use triclosan as a carbon source. The results further suggest the potential for selection of Vibrio in coastal environments, especially sediments, where triclosan may accumulate at high levels.
Recurrent insulinoma in a 10-year-old boy with Down's syndrome
Authors: Ahmad Noman , Almutawa Abdulmonem Mohammed , Abubacker Mohamed Ziyad , Elzeftawy Hossam Ahmed , Bawazir Osama Abdullah
Published: May 2017

An insulinoma is a rare tumour with an incidence of four cases per million per year in adults. The incidence in children is not established. There is limited literature available in children with insulinoma, and only one case is reported in association with Down’s syndrome in adults. Insulinoma diagnosis is frequently missed in adults as well as in children. The Whipple triad is the most striking feature although it has limited application in young children. Hypoglycaemia with elevated insulin, C-peptide and absent ketones is highly suggestive of hyperinsulinism. We present a case of 10-year-old boy with Down’s syndrome with recurrent insulinoma. He was initially misdiagnosed as having an adrenal insufficiency and developed cushingoid features and obesity secondary to hydrocortisone treatment and excessive sugar intake. The tumour was successfully localised in the head of the pancreas with an MRI and octreotide scan on first presentation. Medical treatment with diazoxide and octreotide could not achieve normal blood glucose levels. The insulinoma was laparoscopically enucleated and pathological examination confirmed a neuroendocrine tumour. Subsequently, he had complete resolution of symptoms. He had a recurrence after 2 years with frequent episodes of hypoglycaemia. The biochemical workup was suggestive of hyperinsulinism. MRI and PET scan confirmed the recurrence at the same site (head of the pancreas). He had an open laparotomy for insulinoma resection. The pathology was consistent with benign insulinoma, and subsequently, he had complete resolution of symptoms.

Learning points:

Insulinoma is a very rare tumour in children; it should be considered in the differential diagnosis of hypoglycaemia with absent ketones.

Refractory neurological symptoms like seizure, migraine, mood changes and regression of learning abilities should suggest evaluation for hypoglycaemia.

MRI with contrast and PET scan would localise the majority of pancreatic beta islet cell lesions.

Medical treatment with diazoxide, octreotide and the addition of corn starch in feeds is not curative but can be supportive to maintain normoglycemia until the surgical resection.

Surgical resection is the only curative treatment. The surgical procedure of choice (laparoscopic/open laparotomy) depends on local expertise, preoperative localisation, tumour size and number.

Surgical treatment results in complete resolution of symptoms, but all cases should be closely followed up to monitor for recurrence. The recurrence rate is four times higher in MEN1 cases.
The interfaces between vitamin D, sleep and pain
Authors: de Oliveira Daniela Leite , Hirotsu Camila , Tufik Sergio , Andersen Monica Levy
Published: May 2017

The role of vitamin D in osteomineral metabolism is well known. Several studies have suggested its action on different biological mechanisms, such as nociceptive sensitivity and sleep–wake cycle modulation. Sleep is an important biological process regulated by different regions of the central nervous system, mainly the hypothalamus, in combination with several neurotransmitters. Pain, which can be classified as nociceptive, neuropathic and psychological, is regulated by both the central and peripheral nervous systems. In the peripheral nervous system, the immune system participates in the inflammatory process that contributes to hyperalgesia. Sleep deprivation is an important condition related to hyperalgesia, and recently it has also been associated with vitamin D. Poor sleep efficiency and sleep disorders have been shown to have an important role in hyperalgesia, and be associated with different vitamin D values. Vitamin D has been inversely correlated with painful manifestations, such as fibromyalgia and rheumatic diseases. Studies have demonstrated a possible action of vitamin D in the regulatory mechanisms of both sleep and pain. The supplementation of vitamin D associated with good sleep hygiene may have a therapeutic role, not only in sleep disorders but also in the prevention and treatment of chronic pain conditions.
BIOLOGICAL ASPECTS OF ANAEROBIC DIGESTION AND ITS KINETICS: AN OVERVIEW
Authors: Munisamy Prathaban , Ravichandran Mythili , Devi Natarajan Sharmila , Varadhaaraju Chandrasekar
Published: May 2017

Anaerobic digestion is an anoxic microbiological process occurring in natural environments. Though, the process is considered to be the oldest, its concept relies on the fourth generation biofuel for direct sequestration of carbon-di-oxide into methane. However, the process is successful in natural environments in the efficiency of methane yield with compared to pilot or industrial scale. An overview of an anaerobic digestion and its kinetics is detailed in this review for the successful digestion process, which includes microbiological process, methanogenic interactions, operational conditions of the digester, substrate requirements and its limitation, substrate enhancement by pretreatment and co-digestion process and other rate limiting parameters affecting the process in order to increase the efficiency of methane production.
POLYHYDROXYALKANOATES: BIOSYNTHESIS TO COMMERCIAL PRODUCTION- A REVIEW
Authors: Kaur Loveleen , Khajuria Robinka , Parihar Leena , Dimpal Singh G.
Published: May 2017

The global increase in petroleum prices and the growing concern about the harmful effects of petroleum based plastics has led to a shift from a petroleum based economy to a natural feedstock based economy. One of the major outcomes of this economy shift is the global acceptance of biobased plastics such as Polyhydroxyalkanoates (PHAs) as a replacement for traditional plastics. Even though PHAs have been described as useful polymers due to their intrinsic biodegradability and biocompatibility, the high price has limited their application significantly. The raw material cost has been known to contribute significantly to the manufacturing cost of PHA. Production of PHAs using agro-industrial residues offers an alternative use of low-cost feedstock to produce materials with appropriate physicochemical properties to be used in a broad range of applications. Therefore, much research has been carried out using renewable cheap raw materials such as molasses, lignocellulosic wastes, sewage, industrial by-products, whey etc. to replace the expensive commercial medium, which should reduce the overall production cost. This review highlights various microorganisms, substrates and fermentation strategies used for economical production of PHA.
ENZYMATIC CHARACTERIZATION OF YEAST STRAINS ORIGINATED FROM TRADITIONAL MIHALIC CHEESE
Authors: Karasu-Yalcin Seda , Senses-Ergul Sule , Yesim Ozbas Z.
Published: May 2017

Yeasts, associated with secondary flora of many cheese types, are important microorganisms for cheese ripening process. The aim of this study was to identify the yeasts isolated from traditional Mihalic cheese and to determine their enzymatic activities as a tool for their technological characteristics. Phenotypic identification was performed by using API ID 32C test system and some complementary morphological, physiological and biochemical tests. Enzyme profiles of the isolates were determined by using API-ZYM strips. In this study, 72 yeast isolates were obtained from 29 Mihalic cheese samples. Fifty-six (78%) of the isolates could be identified at species level, and one isolate at genus level. The identified yeast species belonged to three genera; Candida, Geotrichum and Trichosporon. It was determined that Candida famata var. famata was the dominant species in Mihalic cheese. The yeast isolates had variable enzyme activities including acid phosphatase, esterase, esterase lipase, lipase, β-galactosidase, leucine arylamidase, valine arylamidase and cysteine arylamidase, which could have important attributes during cheese ripening. C. famata var. famata M22, Candida guilliermondii var. membranefaciens M54 and Candida tropicalis M2 were selected to be superior strains on the basis of their enzyme profiles. Identification and enzymatic characterization of the yeasts originated from Mihalic cheese was performed for the first time in this study.
MICROBIOLOGICAL QUALITY OF MOROCCAN LABELED EUPHORBIA RESINIFERA HONEY
Authors: Moujanni Abdelkarim , Terrab Anass , Eddoha Rabiaa , Nasser Boubker , Benbachir Maryam , Eddine Chaouqy Nour , Bouzid Taoufiq , Khalid Essamadi Abdel
Published: May 2017

In the present work, microbiological profile of thirty-seven samples of labeled honey were collected in a Protected Geographical Indication “PGI” area of Tadla-Azilal region, which is an endemic zone of Euphorbia resinifera plant. A profile was assessed using conventional microbial methods, like enumeration, detection and/or germs identification, in accordance with ISO norms. This is the first study in which a honey with Moroccan “PGI” was tested, in order to assess its compliance with bacteriological recommendations. Coliforms (Total and fecal Coliforms), Salmonella spp., Shigella spp., Sporus of Bacillus cereus and Clostridium perfringens were not detected. The numbers of Standard Plate Count “SPC” were less than 102 CFU.g-1 for all samples. The molds and yeasts were found among samples and 32% and 40% of samples were positive, respectively. However, no samples showed a higher value than recommended limit [102 CFU.g-1]. We conclude that samples of labeled euphorbia honey of Tadla-Azilal analyzed present good commercial quality parameters (SPC, molds and yeasts “absence of unwanted fermentations”), a good sanitary quality (absence of coliforms and S. aureus) and are safe (Slam., Shig., Sporus of B. cereus and C. perf.). Standardization (regulation and specifications) and a rationalization of beekeeping techniques throughout Euphorbia “PGI” area studied may further sustainably improve the quality of this unique honey, and ensure it over the years.
IN VITRO ANTIOXIDANT EFFICACY OF EPS OBTAINED FROM MICROCOCCUS LUTEUS SNIST- CM 02: A BRIEF STUDY
Authors: Vinoshna Sama , Akula Manikanta , Mishra Bishwambhar
Published: May 2017

The polysaccharides biosynthesized by the microorganisms had emerged as an important class of bioactive compound from the last two decades. In the present study, an attempt was taken to evaluate the in vitro antioxidant activity of EPS produced by Micrococcus luteus SNIST-CM02. The scavenging assays involving 1, 1-diphenyl-2-picrylhydrazyl (DPPH), superoxide radicals, hydroxyl radicals, chelating ability and inhibition effect of lipid peroxidation, for the biosynthesized EPS were studied in order to evaluate the in vitro antioxidant activity. The EC50 value of EPS for DPPH, superoxide radicals and hydroxyl radicals was found to be 8.11 mg/mL, 8.00 mg/mL and 10.25 mg/mL respectively. The EPS had a lower inhibition effect of lipid peroxidation than that of ascorbic acid and butylated hydroxytoluene. At a concentration of 12.0 mg/mL, the inhibition was only 70.00%. These results suggest that the EPS synthesized by Micrococcus luteus SNIST- CM02 can be used as a good potential antioxidant and can be added to different types of food as a novel antioxidant.
MICROWAVE MUTAGENESIS OF BREVIBACILLUS PARABREVIS FOR ENHANCED CELLULASE PRODUCTION, AND INVESTIGATION ON THERMOSTABILITY OF THIS CELLULASE
Authors: Khambhala Pinakin , Paliwal Purva , Kothari Vijay
Published: May 2017

Microwave mutagenesis of Brevibacillus parabrevis for enhanced cellulase production was attempted. Though microwave treatment could alter the cellulase activity of the test bacterium, none of the mutants obtained were found to be genetically stable, indicating the reversible nature of microwave-induced mutation(s). Thermal stability of the B. parabrevis cellulase was also investigated. This enzyme was found to be capable of retaining its activity even after heat treatment (50-121ºC, for 30-60 min). Fluorescence spectrum revealed a red shift in the emission maxima of the heat-treated enzyme preparations, indicating some structural change upon heating, but no major loss of activity was observed. This enzyme was found to be active over a broad temperature range, with 90ºC as the optimum temp, which is interesting as the producing organism is a mesophile.
ANTIOXIDANT ACTIVITY OF PHENOLS AND FLAVONOIDS CONTENTS OF AQUEOUS EXTRACT OF PELARGONIUM GRAVEOLENS ORGIN IN THE NORTH-EAST MOROCCO
Authors: El Ouadi Y. , Bendaif H. , N. Mrabti H. , Elmsellem H. , Kadmi Y. , Shariati M.A. , Abdel-Rahman I. , Hammouti B. , Bouyanzer A.
Published: May 2017

The objective of this work is to characterize the phenols and flavonoids compounds of extracts of Pelargonium Graveolens from North-East Morocco (TAZA) in terms of antioxidant activity. The antioxidant activity of this aromatic plant was determined according to the DPPH radical scavenging assay to suggest it as a new potential source of natural antioxidants. The quantification of phenolics and flavonoids compounds of solvent extracts (diethyl ether and ethyl acetate) were determined spectrometrically. The DPPH scavenging activity of extracts increased in the order diethyl ether extract < ethyl acetate extract < ascorbic acid. Based on these results, we suggest that the phenols and flavonoids compounds of Pelargonium Graveolens have significant potential as a natural antioxidant.
PRESUPPOSITIONS OF (HUMAN MOVEMENT) SCIENCE
Authors: Woudenberg René Van
Published: May 2017

This paper argues that science, human movement science included, proceeds from many presuppositions. First, it explains what sorts of things presuppositions are. Next, it argues that science proceeds from metaphysical, epistemic, and normative presuppositions. The argument entails that neither scientism nor Naturalism is a presupposition of science.
Porous Silicon Multilayer Mirrors and Microcavity Resonators for Optoelectronic Applications
Authors: Chan S. , Tsybeskov L. , Fauchet P.M.
Published: May 2017

Porous silicon multilayer structures are easily manufactured using a periodic current density square pulse during the electrochemical dissolution process. The difference in porosity profile, corresponding to a variation in current density, is attributed to a difference in refractive index. Manipulating the difference in refractive index, high quality optical filters can be made with a maximum reflectivity peak ˜ 100%. The next logical step to further exploit these optical mirrors is to incorporate them into an LED device. The benefit of adding a multilayer mirror below a luminescent film of porous silicon is to significantly reduce the amount of light loss to the silicon substrate and increase the light output. However, oxidation is required to stabilize the as-anodized porous silicon film. This disrupts the overall index profile of the multilayer stack, causing the peak reflectance to blue shift. This phenomenon must be quantified and accounted before device implementation. We present a detailed study on the effects of oxidation temperature, gas environment, and annealing time of porous silicon multilayer structures in a
device configuration.
Silicon-Based UV Detector Prototypes Using Luminescent Poroussilicon Films
Authors: Peraza Limarix , Cruz Madeline , Estrada Angel , Navarro Carlos , Avalos Javier , Fonseca Luis F. , Resto Oscar , Weisz S. Z.
Published: May 2017

The luminescent properties of porous silicon (PSi) films in the visible region were used to improve the photoresponse of PSi/Si-wafer and PSi/Si p-n junctions UV detector prototypes in the region below 500nm. A luminescent PSi overlayer was formed on top of the Si wafers and p-n junctions by electrochemical anodization. These overlayers have emission spectra peaking close to 690nm. In the case of the PSi/Si wafer, the PSi film was produced with a high optical transparency above 600nm and highly absorbent below this value. With such characteristics, the incident UV radiation is partially absorbed and converted into visible radiation that can be highly transmitted through the PSi film and efficiently absorbed by the wafer or the junction. The UV measurements show enhancement of the photoresponse at 366nm as compared with control prototypes without PSi. Details about the enhancement process are discussed.
Integration of Multilayers in Er-Doped Porous Silicon Structures and Advances in 1.5 μm Optoelectronic Devices
Authors: Lopez H. A. , Chan S. , Tsybeskov L. , Koyama H. , Bondarenko V. P. , Fauchet P. M.
Published: May 2017

Infrared photoluminescence (PL) and electroluminescence (EL) from erbium-doped porous silicon (PSi) structures are studied. The PL and EL from the Er-doped PSi structures and the absence of silicon band edge recombination, point defect, and dislocation luminescence bands suggest that the Er-complex centers are the most efficient recombination sites. PSi multilayers with very high reflectivity (R ≥ 90%) in the 1.5 gim range have been incorporated in the structures resulting in a PL enhancement of over 100%. Stable and intense EL is obtained from the Er-doped structures. The EL spectrum is similar to that of the PL, but shifted towards higher energy. The unexpected shift in emission opens up the possibility for erbium related luminescence to encompass a larger part of the optimal wavelength window for fiber optic communications.
Enhancing the External Quantum Efficiency of Porous Silicon LEDs Beyond 1 % by a Post-Anodization Electrochemical Oxidation
Authors: Gelloz B. , Nakagawa T. , Koshida N.
Published: May 2017

External quantum efficiencies (EQEs) of electroluminescent devices based on porous silicon (PS) reported to date are still below the minimum requirements for practical applications such as display devices (1 %) and optical interconnection (10 %). Post-anodization anodic oxidation of PS to enhance the EQE of electroluminescence from devices based on a thin transparent indium tin oxide contact mounted on either porosified n+-type silicon or p+n+-type silicon has been investigated. Enhancement of EQE by more than 2 orders of magnitude has been achieved on our devices. CW EQE of 0.51% has been obtained by using a single anodically oxidized n+-type porous layer. The device based on the p+n+ substrate yielded a CW EQE of 1.1 %, with a power efficiency of 0.08%. It is the first time that EQE greater than 1% is obtained. Furthermore, anodically oxidized devices show better stability than non-oxidized devices. The anodic oxidation proceeds in such a way that it mainly decreases the size of nonconfined silicon in PS. The dramatic enhancement in EQE can therefore be explained by preferential reduction of leakage carrier flow through non-confined silicon.
Enhancement in Efficiency and Stability of Oxide-Free Blue Emission from Porous Silicon by Surface Passivation
Authors: Mizuno H. , Koshida N.
Published: May 2017

The establishment of tuning techniques of visible emission from porous silicon (PS) is very important from both physical and technological viewpoints. As previously reported that the photoluminescence (PL) spectra of PS can continuously be controlled from red to blue simply by postanodization illumination method without any growth of the surface oxide. Details of this oxide-free blue emission have been studied in terms of the PL decay dynamics and surface chemistry. We report here that post-preparation exposure of PS to hydrogen gas is very useful for improvement in efficiency and stability of blue PL. Based on this technique, it has become possible to get blue electroluminescence even at low bias voltages.
Plasmons on Luminescent Porous Silicon Prepared with Ethanol and Critical Point Drying
Authors: Resto O. , Fonseca L. F. , Weisz S. Z. , Many A. , Goldstein Y.
Published: May 2017

We investigated the plasmon characteristics on luminescent porous silicon using electron energy loss spectroscopy. The samples were prepared from p-type crystalline silicon, (100) face, using the conventional electrochemical etching technique with the usual solution of HF, ethanol and water, followed by a critical point drying process. The energy of the bulk plasmon was measured both before and after sputter cleaning the sample with argon-ion bombardment. We found that initially the plasmon energy was slightly higher, ∼18 eV, than the plasmon energy of crystalline silicon. After sputter cleaning the sample with 5 keV Ar+ ions, the plasmon energy increased to ∼20 eV. Exposure to the electron beam used for the measurements caused a slow upward shift of the plasmon energy as a function of time, toward a saturation energy of 22-23 eV, an energy close to the plasmon energy of SiC. Auger spectroscopy performed in parallel showed an increasing carbon coverage. We prepared also samples without ethanol in the etching solution and/or with no critical point drying. Samples that did not undergo the critical point drying process showed consistently a practically constant plasmon energy, with almost no change upon sputtering and/or exposure to the electron beam. On the other hand, samples that were prepared with or without ethanol but using the critical point drying process, showed an appreciable increase in the plasmon energy upon exposure to the electron beam.

We conclude that traces of CO2, used in the critical point drying process, are stored in the pores of the porous silicon surface and serve as a source of carbon. Apparently, upon activation by argon bombardment or by the electron beam, the carbon interacts with the porous Si surface forming a carbon-silicon compound, most probably SiC.
Optically Detected Magnetic Resonance and Double Beam Photoluminescence of CdS/HgS/CdS Nanoparticles
Authors: Porteanu H. , Glozman A. , Lifshitz E. , Eychmüller A. , Weller H.
Published: May 2017

CdS/HgS/CdS nanoparticles consist of a CdS core, epitaxially covered by one or two monolayers of HgS and additional cladding layers of CdS. The present paper describes our efforts to identify the influence of CdS/HgS/CdS interfaces on the localization of the photogenerated carriers deduced from the magneto-optical properties of the materials. These were investigated by the utilization of optically detected magnetic resonance (ODMR) and double-beam photoluminescence spectroscopy. A photoluminescence (PL) spectrum of the studied material, consists of a dominant exciton located at the HgS layer, and additional non-excitonic band, presumably corresponding to the recombination of trapped carriers at the interface. The latter band can be attenuated using an additional red excitation. The ODMR measurements show the existence of two kinds of electron-hole recombination. These electron-hole pairs maybe trapped either at a twin packing of a CdS/HgS interface, or at an edge dislocation of an epitaxial HgS or a CdS cladding layer.
Light Induced ESR Measurements on Microcrystalline Silicon with Different Crystalline Volume Fractions
Authors: Müller J. , Finger F. , Hapke P. , Wagner H.
Published: May 2017

Microcrystalline silicon with various crystalline volume fractions was prepared by plasma enhanced chemical vapour deposition. The material was studied by steady state and transient electron spin resonance in the dark and under light illumination. The observed resonances at g-values of 2.01, 2.0052, 2.0043, 1.998 can be attributed to the amorphous and microcrystalline constituents, and their respective intensities change as the ratio of amorphous to crystalline volume is varied. The origin of a fifth resonance at g = 1.995 remains unclear. Smaller crystalline volume fractions lead to lower spin densities and affect the recombination behaviour of photogenerated charge carriers. The recombination behaviour in highly crystalline material is also influenced by moderate Fermi level shifts, where differences show up between n-type (or undoped) and p-type samples. The differences are attributed to trapping of photo-generated holes in deep states within the disordered regions.
Light Emitting Micropatterns of Porous Semiconductors
Authors: Lockwood D. J. , Schmuki P. , Erickson L. E.
Published: May 2017

We report a principle that allows writing visible light emitting semiconductor patterns of arbitrary shape down to the sub-micrometer scale. We demonstrate that porous semiconductor growth can be electrochemically initiated preferentially at surface defects created in an n-type substrate by Si++ focused ion beam bombardment. For n-type material in the dark, the electrochemical pore formation potential (Schottky barrier breakdown voltage) is significantly lower at the implanted locations than for an unimplanted surface. This difference in the threshold voltages is exploited to achieve the selectivity of the pore formation process. Visible light emitting patterns of porous Si and GaAs have been created in this way. At present, the size of the structures is limited only by the diameter of the writing ion beam, and pattern diameters in the 50–200-nm range are possible.
VLS Growth of Si nanowhiskers on a H-terminated Si{111} surface
Authors: Ozaki N. , Ohno Y. , Takeda S. , Hirata M.
Published: May 2017

We have grown Si nanowhiskers on a Si{1111} surface via the vapor-liquid-solid (VLS) mechanism. The minimum diameter of the crystalline is 3nm and is close to the critical value for the effect of quantum confinement. We have found that many whiskers grow epitaxially or non-epitaxially on the substrate along the 〈112〉 direction as well as the 〈111〉 direction.

In our growth procedure, we first deposited gold on a H-terminated Si{111} surface and prepared the molten catalysts of Au and Si at 500°C. Under the flow of high pressure silane gas, we have succeeded in producing the nanowhiskers without any extended defects. We present the details of the growth condition and discuss the growth mechanism of the nanowhiskers extending along the 〈112〉 direction.
In-Situ X-ray Diffraction Study of Lithium Intercalation in Nanostructured Anatase Titanium dioxide
Authors: Krol R. Van de , Meulenkamp E. A. , Goossens A. , Schoonman J.
Published: May 2017

Electrochemical lithium intercalation in nanostructured anatase TiO2 is investigated with in-situ X-ray diffraction. A complete and reversible phase transformation from tetragonal anatase TiO2 to orthorhombic anatase Li0.5TiO2 is observed. The difference of the XRD spectra before and after insertion can be fitted with the lattice parameters of the two phases as fit parameters. The maximum amount of lithium that can be dissolved in anatase TiO2 before the phase transformation occurs is found to be very small.
Novel Electronic Conductance CO2 Sensors Based on Nanocrystalline Semiconductors
Authors: Baraton M.-I. , Merhari L. , Keller P. , Zweiacker K. , Meyer J.-U.
Published: May 2017

We have recently demonstrated that screen-printed sensors using a 20 nm- instead of microsized BaTiO3-CuO-additives powder exhibit up to one order of magnitude higher sensitivity to CO2. In this paper, we focus on both the surface chemistry of the nano-BaTiO3- CuO-additives powder (mix-BaTiO3) and electrical changes during O2 and CO2 adsorptions. We show by Fourier transform infrared (FTIR) spectrometry, thus without using electrodes, that the mix-BaTiO3 system behaves like a p-type semiconductor at the operating temperature. The variations of the electrical conductivity versus CO2 concentrations are followed in situ by FTIR spectrometry and prove to be dependent on the surrounding oxygen. These IR results are then correlated to the electrical measurements performed on the sensor. Preliminary electrical response modelling shows a good agreement with the surface barrier layer theory.
In Situ Diagnostics of Nanomaterial Synthesis by Laser Ablation: Time-resolved Photoluminescence Spectra and Imaging of Gas-Suspended Nanoparticles Deposited for Thin Films
Authors: Geohegan D. B. , Puretzky A. A. , Meldrum A. , Duscher G. , Pennycook S. J.
Published: May 2017

The dynamics of nanoparticle formation by laser ablation into background gases are revealed by gated-ICCD photography of photoluminescence (PL) and Rayleigh-scattering (RS) from gas-suspended nanoparticles. These techniques, along with gated-spectroscopy of PL from isolated, gassuspended nanoparticles, permit fundamental investigations of nanomaterial growth, doping, and luminescence properties prior to deposition for thin films. Using the time-resolved diagnostics, particles unambiguously formed in the gas phase were collected on TEM grids. Silicon nanoparticles, 1-10 nm in diameter, were deposited following laser ablation into 1-10 TorrAror He. Three in situ PL bands (1.8, 2.6, 3.2 eV) similar to oxidized porous silicon were measured, but with a pronounced vibronic structure. Structureless photoluminescence bands were reproduced in the films (2.1, 2.7, 3.2 eV) only after standared annealing. The ablation of metal zinc into Ar/02 is also reported for the preparation of < 10 nm diameter hexagonal zincite nanocrystals, The particles were analyzed by bright field and Z-contrast TEM and high resolution EELS.
Microstructure and Sensing Properties of Cryosol Derived Nanocrystalline Tin Dioxide
Authors: Kudryavtseva S. M. , Vertegel A. A. , Kalinin S. V. , Kheifets L. I. , Landuyt J. Van , Meshkov L. L. , Nesterenko S. N. , Rembeza E. S. , Gaskov. A. M.
Published: May 2017

The powders of nanocrystalline tin dioxide were prepared by two different methods: conventional hydrolysis of SnCl4 in aqueous solution and novel cryosol technique. The microstructure, composition, and electrical properties of the samples were investigated. The sintered pellets obtained by means of the cryosol method are characterized by significantly higher values of electrical resistance as compared to those prepared by conventional technique. A significant effect of the microstructure on the sensing properties of nanocrystalline SnO2 has been found. The sensitivity to H2S of the samples synthesized by cryosol method was shown to be higher than that of the samples obtained by traditional precipitation.
Characterization of ZnSe Nanoparticles Prepared Using Ultrasonic Radiation Method
Authors: Xu Jianfeng , Ji Wei , Tang Sing-Hai , Huang Wei
Published: May 2017

ZnSe nanoparticles with an average size of 15 nm were prepared using the ultrasonic radiation method. The characterization was carried out by means of XRD, TEM, XPS and Raman scattering spectroscopy. The experimental results indicate that the as-prepared powders are composed of ZnSe with zinc-blende structure. The high purity of ZnSe particles was confirmed by XPS analysis. In the Raman spectra, TO and LO phonon modes were observed at 205 and 257 cm−1 in the ZnSe nanoparticles.
Surface Stoichiometry of CdSe Nanocrystals
Authors: Taylor Jason , Kippeny Tadd , Bennett Jonathan C. , Huang Mengbing , Feldman Leonard C. , Rosenthal Sandra J.
Published: May 2017

Rutherford backscattering spectroscopy (RBS) has been applied to determine the constitution of prototypical CdSe nanocrystals synthesized by the high temperature pyrolysis of organometallics in trioctylphosphine oxide (TOPO). The diameter of the nanocrystals was varied from 22 Å to 58 Å. For all nanocrystal sizes the nanocrystals are Cd rich with an average Cd:Se ratio of 1.2 ± 0.1. The Cd:Se stoichiometery is independent of the starting Cd:Se ratio used for nanocrystal preparation, indicating the excess Cd is not associated with the initial abundance but is an intrinsic property of nanocrystals prepared by this method. The size dependence of excess Cd indicates the extra Cd is on the surface of the crystallite. The coverage of the surface passivating TOPO ligands has also been determined and is larger than reported in previous X-ray photoelectron spectroscopy (XPS) studies of Bowen Katari et al. The origin and structural implications of non-stoichoimetric Cd are discussed.
Structural and Electronic Properties of Laser Crystallized Silicon Films
Authors: Sameshima T.
Published: May 2017

Fundamental properties of silicon films crystallized by a 30-ns-pulsed XeCI excimer laser were discussed. Although crystallization of 50-nm thick silicon films formed on quartz substrates occurred through laser hearing at the crystalline threshold energy density of 160 mJ/cm2, a higher laser energy density at 360 mJ/cm2 was necessary to crystallize silicon films completely. Analyses of free carrier optical absorption revealed that phosphorus-doped silicon films with a carrier density about 2×1020 cm−3 had a high carrier mobility of 20 cm2/Vs for irradiation at the crystallization threshold energy density, while Hall effect measurements gave a carrier mobility of electrical current traversing grain boundaries of 3 cm2/Vs. This suggested that the crystalline grains had good electrical properties. As the laser energy density increased to 360 mJ/cm2 and laser pulse number increased to 5, the carrier mobility obtained by the Hall effect measurements markedly increased to 28 cm2/Vs because of improvement of grain boundary properties, while the carrier mobility obtained by analysis of free carrier absorption increased to 40 cm2/Vs. A post annealing method at 190°C with high-pressure H2O vapor was developed to reduce the density of defect states. Increase of carrier mobility to 500 cm2/Vs was demonstrated in the polycrystalline silicon thin film transistors fabricated in laser crystallized silicon films.
Phase Segregation in Sipos: Formation of Si Nanocrystals
Authors: Vilà A. , Morante J. R. , Caussat B. , Barathieu P. , Scheid E.
Published: May 2017

A characterization of Semi-insulating Polycrystalline Silicon (SIPOS) layers deposited from SiH4 on SiO2 is presented, as a function of growth and annealing conditions (time and temperature), in order to better understand the processes involved in nucleation of silicon nanocrystals. Correlation between optical and XPS measurements allows determination of the starting composition of the amorphous material. After annealing, Fourier transform infrared (FTIR), ultraviolet-visible and Raman spectroscopies have been used to determine the structural and optical characteristics of the resulting material. Thermal treatment promotes a phase separation, modifying the layer properties and degrading the electrical insulation characteristics. Concentration of the silicon dioxide phase increases, whereas elemental silicon precipitates into nanocrystals which nucleate near the interface with the underneath SiO2. Their density depends of the initial silicon content in the SIPOS layer, and some directions such as <1I1> and <220> grow preferentially whereas other directions such as <311> show a slower growth. As the percentage of oxygen increases, the formation of precipitates is less marked.
Electron Beam Excited Plasma CVD for Silicon Growth
Authors: Okitsu'l K. , Imaizumi M. , Ito T. , Yamaguchi K. , Yamaguchi M. , Hara T. , Ban M. , Tokai M. , Kawamura K.
Published: May 2017

Electron beam excited plasma (EBEP) CVD is a novel fabrication route for poly Si. Deposition was carried out on Si and SiO2 layer from pure SiH4 without hydrogen dilution. Crystalline silicon (μc-Si:H) films were made with electron acceleration voltage, discharge current, source gas flow rate, chamber presser, substrate temperature varied systematically. Average grain size was about 10 nm. Crystalline ratio was up to 0.7 at the maximum. The films contain about 19 at% hydrogen in spite of no dilution. It is considered that EBEP supplies much about atomic hydrogen due to the high decomposability of the source gas.
Light Emitting Nanostructures in Implanted Silicon Layers
Authors: Plugaru R. , Piqueras J. , mendez B. , Craciun G. , Nastase N.
Published: May 2017

Structural changes in amorphous silicon layers have been investigated as a process route to obtain light emitting silicon nanostructures. The optical emission of the layers was studied by cathodoluminescence (CL). Under 1013 -1014 boron ions/cm2 implantation, nanosized crystalline structures grow in the amorphous matrix. A dominant emission band, centered at 400 nm, appears in the catodoluminescence spectrum of the low dose implanted film, while spectra with a 400 nm intense band and 480–500 nm and 650 weak bands are characteristic of higher dose implanted and anodized layers. The structural changes are correlated with the emission properties in the 400–650 nm range.
Porosity-Induced Optical Phonon Engineering in III-V Compounds
Authors: Tiginyanu I. M. , Irmer G. , Monecke J. , Hartnagel H. L. , Vogt A. , Schwab C. , Grob J.-J.
Published: May 2017

New possibilities for modifying the phonon spectra of III-V compounds are evidenced by micro-Raman analysis of porous layers prepared by electrochemical anodization of (111 )Aoriented n-GaP substrates. In particular, a surface-related vibrational mode along with a porosity-induced decoupling between the longitudinal optical (LO) phonon and plasmon are observed. We prove that filling in the pores with other materials (aniline as a first approach) is a promising tool for controlling the surface phonon frequency.
FIRST RECORD OF EIGHTBAR GROUPER, Epinephelus octofasctafus GRIFFIN, 1926 (PERCIFORMES: SERRANIDAE) FROM INDONESIA
Authors: Peristiwady Teguh
Published: May 2017

Three specimens were collected by market collection at Winenet and Girian Market, Bitung, North Sulawesi, lndonesia on January until March 2008.
Delayed Intervention of Small Renal Masses on Active Surveillance
Authors: Gupta Mohit , Blute, Jr. Michael L. , Su Li-Ming , Crispen Paul L.
Published: May 2017

Although surgical excision is the standard of therapy for small renal masses (SRMs), there is a growing recognition of active surveillance as an option in select patients who are poor surgical candidates or who have shorter life expectancy. A number of patients on expectant management, however, subsequently advance to definitive therapy. In this study, we systematically reviewed the literature and performed a pooled analysis of active surveillance series to evaluate the rate and indications for definitive treatment after initiating a period of active surveillance. Fourteen clinical series (1245 patients; 1364 lesions) met our selection criteria. Mean lesion size at presentation was 2.30 ± 0.40 cm with a mean follow-up of 33.6 ± 16.9 months. Collectively, 34.0% of patients underwent delayed intervention, which ranged in individual series from 3.6% to 70.3%. Of patients undergoing delayed intervention, the average time on active surveillance prior to definitive treatment was 27.8 ± 10.6 months. A pooled analysis revealed that 41.0% of patients underwent therapy secondary to tumor growth rate and 51.9% secondary to patient or physician preference in the absence of clinical progression. Overall, 1.1% of all patients progressed to metastatic disease during the average follow-up period. Thus, active surveillance may be an appropriate option for carefully selected patients with SRMs. However, delayed treatment is pursued in a significant percentage of patients within 3 years. Prospective registries and clinical trials with standardized indications for delayed intervention are needed to establish true rates of disease progressions and recommendations for delayed intervention.
SENSITIVITY TO ENVIRONMENTAL STRESS OF PRATA,JAPIRA AND VITÓRIA BANANA CULTIVARS PROVEN BY CHLOROPHYLL a FLUORESCENCE
Authors: SANTOS PRISCILA NOBRES DOS , SILVA DIOLINA MOURA , GALLON CAMILLA ZANOTTI , VENTURA JOSÉ AIRES
Published: May 2017

ABSTRACT This study aimed to evaluate the physiological responses to environmental stress during pre- and post-harvest of the following banana cultivars: Prata (AAB), Japira (AAAB) and Vitoria (AAAB). Analyses were carried out on young plants at vegetative stage (daughter-plant) and adult plants at reproductive stage (motherplant). The experimental design was completely randomized. In the in vivo pre-harvest analysis were used seven replications, in a factorial scheme (3x2x2), three cultivars and two stages (vegetative and reproductive) and two collection periods (March and June). For the analysis of post-harvest quality were used five replications in a factorial design (3x2x5), corresponding to three cultivars, two development stages and five periods of post-harvest analysis, carried out every two days from stage 4 of fruit ripening. The chlorophyll a fluorescence emission kinetics showed low photochemical performance of the three cultivars in June, a period characterized by lower temperatures and water deficit. Prata was the cultivar with the lowest tolerance to abiotic physiological behavior changes, which also reflected in fruit quality, because there was a change in physical and physicochemical parameters. Japira and Vitoria cultivars showed similar physiological responses in the pre- and post-harvest periods, according to their phylogenetic proximity. The total performance index, i.e., the conservation of energy absorbed by PSII up to the reduction of the final PSI acceptors (PItotal) and the di-malonic aldehyde (MDA) content were significantly higher in Japira and Vitoria cultivars compared to Prata cultivar in the reproductive phase. There was no significant change in the potential quantum efficiency of PSII (FV / FM = jP0) among the three cultivars. It was concluded that Japira and Vitoria cultivars showed greater plasticity to tolerate or even adapt to abiotic variations keeping higher fruit yield. PItotal is the most sensitive parameter during the banana life cycle and important tool for distinguishing different cultivars yields.
Bacterial culture and antibiotic sensitivity from the ocular conjunctiva of horses
Authors: Ferreira Ana Raquel de Araújo , Santana Alana Fontenele , Almeida Ana Carolina da Veiga Rodarte de , Sousa Renan Fiel , Perecmanis Simone , Galera Paula Diniz
Published: May 2017

ABSTRACT: The aim of this study was to identify the conjunctival bacterial flora of healthy horses in Brasilia (Distrito Federal, Brazil), and to evaluate the antimicrobial susceptibility of the isolated strains. We examined 200 eyes of 100 healthy adult horses without any eye problems, belonging to the 1st Regiment of the Cavalry Guard (RCG) of the Brazilian Army in Brasilia. Samples were collected from the inferior conjunctival fornix of both eyes. Drug sensitivity test was performed with the antibiotics gentamicin (10µg), tobramycin (10µg), chloramphenicol (30µg) and ciprofloxacin (5µg). Of the 200 samples collected, 131 (65.5%) were considered positive for bacterial growth. A total of 208 bacterial strains belonging to 19 genera were isolated, where there was prevalence of gram-positive bacteria (65%), with Staphylococcus sp. being the species of greatest incidence. It was observed that 94, 85, 81 and 68% of the isolates were sensitive to ciprofloxacin, gentamicin, chloramphenicol and tobramycin, respectively. These results can guide the empirical selection antimicrobial therapy for infections of the ocular surface of horses, pending the identification of the etiologic agent.
BRAZILIAN EFL LEARNERS’ AWARENESS ABOUT L2 PHONES: IS MALL PRONOUNCED AS ‘MAL’?
Authors: Souza Hanna Kivistö-de
Published: May 2017

ABSTRACT The aim of this paper was to examine the extent of non-verbalizable knowledge L1 Brazilian Portuguese (BP) learners of English possess about the segmental inventory of the L2. The study had two aims: i) to determine to what extent L1 BP EFL learners are aware of contrastive and non-contrastive L2 segments, ii) to determine which type of segments present the lowest level of awareness. To the date, little research has been carried out about the non-verbalizable aspect of L2 phonological awareness, most studies having relied on participants’ verbalization of the acquired knowledge (e.g., KENNEDY & TROFIMOVICH, 2010; WREMBEL, 2011). Whereas language learners are frequently taught grammar explicitly, pronunciation of the L2 is rarely addressed in the foreign language classroom. Moreover, phonology is in nature less susceptible to conscious processing than other aspects of L2 learning, making the noticing, and especially the explicit explanation, of phonological aspects difficult. Nevertheless, high L2 phonological awareness is beneficial for L2 pronunciation (KIVISTÖ-DE SOUZA, 2015), making its examination a priority in the foreign language classroom context. The participants of the study were 71 advanced EFL learners and 18 native speakers of American English. Participants performed a perception test which presented English segments spoken by native and non-native speakers. The ability to identify pronunciation deviations in the non-native speaker trials was taken as a measure for phonological awareness. The results showed that the L1 BP participants manifested a significantly lower sensitivity to English segmental phonology than the native English speakers (F[1, 87] = 40.56, p <.001, η2=.31). Pronunciation deviations involving consonants were identified to the greatest extent (52%), whereas the trials involving short-lag VOTs were identified the poorest (33%). The results reveal a need for explicit pronunciation instruction and the employment of consciousness-raising activities in the Brazilian EFL classroom.
DISCURSOS (RE)VELADOS: UMA ANÁLISE DIALÓGICA DAS NOVAS DIRETRIZES PARA FORMAÇÃO DOCENTE
Authors: Nunes Jozanes Assunção
Published: May 2017

RESUMO Em julho de 2015, o Ministério da Educação aprovou as novas Diretrizes Curriculares Nacionais para a Formação Inicial e Continuada dos Profissionais do Magistério da Educação Básica, revogando as Diretrizes de 2002, instituídas pela Resolução CNE/CP n. 01/2002. Sob a perspectiva da teoria dialógica bakhtiniana, este artigo analisa as relações dialógicas que se engendram no Parecer CNE/CP n. 2/2015, que apresenta as novas Diretrizes, focalizando o posicionamento valorativo dos enunciadores com relação ao discurso da formação para as competências. Examina as relações que o Parecer CNE/CP n. 2/2015 estabelece no diálogo com o Parecer CNE/CP n. 009/2001 - que fundamentou as Diretrizes revogadas, e com os discursos oficiais que tratam da formação para as competências, mobilizados no texto. A análise evidencia que ao mesmo tempo em que o discurso do Parecer CNE/CP n. 2/2015 tenta negar vinculação com o modelo de formação baseado em competências - apagando e substituindo termos a ele relacionados - apresenta grande convergência com as diretrizes revogadas, que tomaram o conceito de competências como nuclear para a formação de professores.