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Spatial Distribution of Soil Organic Matter Using Geostatistics: A Key Indicator to Assess Soil Degradation Status in Central Italy

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Pedosphere 2012年第2期22卷 230-242页

作者： A.MArCHETTI C.PICCINI r.FrANCAVIGLIA L.MABIT research Centre for the Soil-Plant System CRA-RPS Via della Navicella 2-4 00184 Rome (Italy) Soil and Water Management & Crop Nutrition Laboratory FAO/IAEA Agriculture & Biotechnology Laboratory IAEA Laboratories Seibersdorf PO Box 100 Wagramerstrasse 5 A-1400 Vienna (Austria)

Soil organic matter (SOM) content is one of the main factors to be considered in the evaluation of soil health and fertility. As timing, human and monetary resources often limit the amount of available data, geostatistical techniques provide a valid scientific approach to cope with spatial variability, to interpolate existing data and to predict values at unsampled locations for accurate SOM status survey. Using geostatistical and geographic information system (GIS) approaches, the spatial variability of some physical and chemical soil parameters was investigated under Mediterranean climatic condition in the Abruzzo region of central Italy, where soil erosion processes accelerated by human induced factors are the main causes of soil degradation associated with low SOM content. Experimental semivariograms were established to determine the spatial dependence of the soil variables under investigation. The results of 250 soil sampling point data were interpolated by means of ordinary kriging coupled with a GIS to produce contour maps distribution of soil texture, SOM content related to texture, and C/N ratio. The resulting spatial interpolation of the dataset highlighted a low content of SOM in relation with soil texture in most of the surveyed area (87%) and an optimal C/N ratio for only half of the investigated surface area. Spatial location of degraded area and the assessment of its magnitude can provide decision makers with an accurate support to design appropriate soil conservation strategies and then facilitate a regional planning of agri-environmental measures in the framework of the European Common Agricultural Policy.

关键词： C/N ratio ordinary kriging soil organic carbon soil quality spatial variability

Sensitization of Hydrothermally Grown Single Crystalline TiO2 Nanowire Array with CdSeS Nanocrystals for Photovoltaic Applications

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Nano research 2011年第12期4卷 1181-1190页

作者： Akshay Kumar Kuan-teh Li Anuj r. Madaria Chongwu Zhou Department of Electrical Engineering and Center for Energy Nanoscience and Technology University of Southern California Los AngelesCA 90089 USA

An oriented array of electron transporting nanowires, grown directly on a transparent conductor constitutes an optimal architecture for efficient photovoltaic applications. In addition, semiconductor nanocrystals can work as efficient light absorbers because of their tunable optical properties. In this paper, we use an oriented array of TiO2 nanowires grown directly on a transparent conductive electrode and subsequently sensitized with colloidally grown CdSeS nanocrystal quantum dots （QDs）, using an efficient bi-linker assisted methodology, to demonstrate photovoltaic cells. Upon excitation with light, exciton dissociation takes place at the nanowire-nanocrystal interface, after which, electrons are transported to the fluorine-doped tin oxide （FTO） electrode via single-crystalline TiO2 nanowire channels. We demonstrate that an ex situ ligand exchange of QDs followed by sensitization on oxygen-plasma treated TiO2 nanowires results in enhanced loading of QDs, as compared to the in situ ligand exchange approach. An array of 1μm long TiO2 nanowire sensitized with CdSeS nanocrystals exhibits photovoltaic effects with a short-circuit current of 2-3 mA/cm2, an open circuit voltage of 0.6-0.7 V and a fill factor of 52-5%, resulting in devices with efficiencies of up to 0.6%.

关键词： TiO2 nanowire semiconductor nanocrystals solar cells hydrothermal growth

Study on Fluorescence Property of Sparfloxacin Derivatizing System and its Application

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Chinese Chemical Letters 2000年第3期11卷 255-258页

作者： Du, LM Zhou, J Xu, QQ Fan, ZF Yuan, r Shanxi Normal Univ Ctr Anal & Test Linfen 041004 Peoples R China

In acid medium, sparfloxacin is oxidized by nitrous acid, then reacts with hydrobromic acid to form a new fluorescence substance, which can emit the strong fluorescence. which is 151 fold more than that of sparfloxacin itself. By this, a new sensitive method for the determination of sparfloxacin in human urine by derivative-synchronous fluorescence is presented with good results.

关键词： sparfloxacin nitrous acid derivative-synchronous fluorescence human urine

Myelin-based inhibitors of oligodendrocyte myelination: clues from axonal growth and regeneration

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Neuroscience Bulletin 2013年第2期29卷 177-188页

作者： Feng Mei S.Y.Christin Chong Jonah r.Chan Department of Neurology Program in Neuroscience and the MS Research GroupUniversity of California

The differentiation of and myelination by oligodendrocytes （OLs） are exquisitely regulated by a series of intrinsic and extrinsic mechanisms. As each OL can make differing numbers of myelin segments with variable lengths along similar axon tracts, myelination can be viewed as a graded process shaped by inhibitory/ inductive cues during development. Myelination by OLs is a prime example of an adaptive process determined by the microenvironment and architecture of the central nervous system （CNS）. In this review, we discuss how myelin formation by OLs may be controlled by the heterogeneous microenvironment of the CNS. Then we address recent findings demonstrating that neighboring OLs may compete for available axon space, and highlight our current understanding of myelin-based inhibitors of axonal regeneration that are potentially responsible for the reciprocal dialogue between OLs and determine the numbers and lengths of myelin internodes. Understanding the mechanisms that control the spatiotemporal regulation of myelinogenic potential during development may provide valuable insight into therapeutic strategies for promoting remyelination in an inhibitory microenvironment.

关键词： differentiation myelin nogo-A LINGO-l semaphorin ephrin netrin-1

Electrochemical drag effect on grain boundary motion in ionic ceramics

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npj Computational Materials 2020年第1期6卷 305-311页

作者： K.S.N.Vikrant Wolfgang rheinheimer r.Edwin García School of Materials Engineering Purdue UniversityWest LafayetteIN 47907USA

The effects of drag imposed by extrinsic ionic species and point defects on the grain boundary motion of ionic polycrystalline ceramics were quantified for the generality of electrical,chemical,or structural driving *** the absence of,or for small driving forces,the extended electrochemical grain boundary remains pinned and symmetrically distributed about the structural *** the grain boundary begins to move,charged defects accumulate unsymmetrically about the structural grain boundary *** the critical driving force for motion,grain boundaries progressively shed individual ionic species,from heavier to lighter,until they display no interfacial electrostatic charge and zero Schottky *** p-n junction moving grain boundaries that induce a finite electrostatic potential difference across entire grains are identified for high velocity *** developed theory is demonstrated for Fe-doped SrTiO_(3).The increase in average Fe concentration and grain boundary crystallographic misorientation enhances grain boundary core segregation and results in thick space charge layers,which leads to a stronger drag force that reduces the velocity of the *** developed theory sets the stage to assess the effects of externally applied fields such as temperature,electromagnetic fields,and chemical stimuli to control the grain growth for developing textured,oriented microstructures desirable for a wide range of applications.

关键词： grain boundary ceramics

Idiopathic chronic pancreatitis:Beyond antioxidants

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World Journal of Gastroenterology 2021年第43期27卷 7423-7432页

作者： rajiv M Mehta Stephen J Pandol Prachi r Joshi Department of Gastroenterology Surat Institute of Digestive Science(SIDS)Hospital and Research CentreSurat 395002GujaratIndia Department of Medicine Cedars-Sinai Medical CenterLos AngelesCA 90048United States Department of Gastroenterology and Clinical research SIDS Hospital and Research CentreSurat 395002GujaratIndia

Chronic pancreatitis(CP)is a complex disease associated with gene-gene or geneenvironment *** incidence of idiopathic CP has shown an increasing trend,withits phenotypeshaving changed considerably in the last two *** diseaseitself can be regulated before it reaches the stage of established CP;however,the etiopathogenesis underlying idiopathic CP remains to be established,making the condition difficult to ***,there also remains a lack of consensus regarding the beneficial effects of antioxidant therapiesfor *** is known that antioxidant therapy does not reduce inflammatory and fibrotic cytokines,making it unlikely that they could modulate the disease *** antioxidants are safe,very few studies to date have reported the long-term beneficial effects in patients with ***,studies are being performed to identify drugs that can improve symptoms and alter the natural history of ***,with their numerous pleiotropic effects,may play a role in the treatment of CP,butin 2006,their use was found to be associated with the undesirable side effect of promoting *** studies showed favourable effects of statins in CP,highlighting the particular benefits of lipophilic statins,such as lovastatin and simvastatin,over the hydrophilic statins,such as ***,studies to repurpose N-acetylcysteine as a CP therapy areyielding very promising results.

关键词： Chronic pancreatitis Simvastatin Antioxidants Quality of life Nacetylcysteine Acute pancreatitis

Structure of Some 4f rare Earth Liquid Metals --A Charged Hard Sphere Approach

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Communications in Theoretical Physics 2006年第2X期46卷 337-342页

作者： P.B. Thakor P.N. Gajjar A.r. Jani Department of Physics Veer Nazmad South Gujarat University Udhana Magdalla Road Surat 395 007 Gujarat India Department of Physics Oujarat University Ahmedabd Oujarat India Department of Physics Sardar Patel University Vallabh Vidyanagar 388 120 Gujarat India

A well-established pseodopotential is used to study the structure of some 4f rare earth liquid metals （Ce, Pr, Eu, Gd, Tb, and Yb）. The structure factor S（q）, pair distribution function g（r）, interatomic distance r1, and coordination number n1 are calculated using Charged Hard Sphere （CHS） reference system. To introduce the exchange and correlation effects, the local field correction due to Sarkar et al. （S） is applied. The present investigation is successful in generating the structural information of Ce, Pr, Eu, Gd, Tb, and Yb 4f rare earth liquid metals.

关键词： pseudopotential structure factor pair distribution function interatomic distance

Surgical management of esophagogastric junction tumors

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World Journal of Gastroenterology 2006年第41期12卷 6608-6613页

作者： Burkhard HA von rahden Hubert J Stein J rüdiger Siewert Department of Surgery Technical University MunichMunichGermany Department of SurgeryUniversity Hospital SalzburgSalzburgAustria Department of Surgery University Hospital SalzburgSalzburgAustria Department of Surgery Technical University MunichMunichGermany

Surgical resection with lymphadenectomy is the mainstay of treatment for all resectable esophagogastric junction tumors, prior to systemic generalization of the disease. This makes accurate pre-treatment staging and classification of the tumors most demanding. A well-established and internationally accepted classification for adenocarcinomas of the esophagogastric junction （AEG） helps to choose the appropriate surgical approach and to make results from different institutions comparable. Distal esophageal adenocarcinomas （AEGⅠ） are distinguished from true cardia carcinomas （AEGⅡ） and subcardiac gastric cancers （AEGⅢ）. Substantial advancements in this surgical field during the preceding decades have clearly revealed that individualization of the surgical strategy is the key to successfully approaching these entities. In this review we discuss the surgical management of esophagogastric junction tumors with a tailored surgical strategy.

关键词： Adenocarcinoma junction Esophageal cancer resection of the esophagogastric Gastric cancer Surgical

Graphene-platinum nanocomposite as a sensitive and selective voltammetric sensor for trace level arsenic quantification

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International Journal of Smart and Nano Materials 2014年第1期5卷 17-32页

作者： r.Kempegowda D.Antony P.Malingappa Department of Chemistry Bangalore UniversityCentral College CampusBangalore 560001India raman research Institute C.V.Raman AvenueBangalore 560080India

A simple protocol for the chemical modification of graphene with platinum nanoparticles and its subsequent electroanalytical application toward sensitive and selective determination of arsenic has been *** modification was carried out by the simultaneous and sequential chemical reduction of graphene oxide and hexachloroplatinic acid in the presence of ethylene glycol as a mild reducing *** synthesized graphene-platinum nanocomposite(Gr-nPt)has been characterized through infrared spectroscopy,x-ray diffraction study,field emission scanning electron microscopy and cyclic voltammetry(CV)*** and square-wave anodic stripping voltammetry have been used to quantify *** proposed nanostructure showed linearity in the concentration range 10-100 nM with a detection limit of 1.1 *** proposed sensor has been successfully applied to measure trace levels of arsenic present in natural sample matrices like borewell water,polluted lake water,agricultural soil,tomato and spinach leaves.

关键词： arsenic graphene-platinum nanocomposite chemical modification square-wave anodic stripping voltammetry spinach leaves