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Average Thickness (average + thickness)
Selected AbstractsRetinal nerve fibre layer of perimetrically unaffected eyes of glaucoma patients: an optical coherence tomography studyCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 2 2009Stefano Da Pozzo MD PhD Abstract Purpose:, The aim of this study is to evaluate whether optical coherence tomography (StratusOCT) may detect early changes in perimetrically unaffected (PU) fellow eyes of glaucomatous patients by assessing retinal nerve fibre layer (RNFL) thickness parameters. Methods:, Thirty-seven glaucomatous patients with unilateral field loss and 34 age-matched controls were recruited. In glaucoma patients, PU and perimetrically affected fellow eyes were analysed separately. For each group, mean values (±SD) of RNFL thickness parameters were calculated and comparisons between fellow eyes of glaucoma patients and between healthy and PU eyes of glaucoma patients conducted with paired t -test and Mann,Whitney U -test, respectively. Proportion of clock-hour sectors flagged with probability <5% or <1% was collected and differences between healthy and PU eyes were evaluated on Fisher exact test. Results:, Global (Average Thickness) and sectoral parameters (Inferior and Nasal Average), Maximum thickness,minimum thickness (Max-min), as well as 2-o'clock (nasal side) and 6-o'clock sectors resulted significantly thinner in PU eyes than in control group. Proportion of eyes with clock-hour position flagged with probability <5% or <1% was not significantly different between healthy and PU eyes. Conclusion:, Despite a standard automated perimetry within normal limits, the StratusOCT detected both localized and diffuse RNFL thinning in PU eyes of glaucoma patients. These eyes should be considered at risk of developing functional damage over time and consequently require thorough monitoring for detecting any sign of progression. [source] Contribution of deep-seated bedrock landslides to erosion of a glaciated basin in southern AlaskaEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2005Ann M. Arsenault Abstract Landslides represent a key component of catchment-scale denudation, though their relative contribution to the erosion of glaciated basins is not well known. Bedrock landslide contribution was investigated on the surface of one of eleven glaciers on a glaciated ridge in the Chugach-St Elias Range of southern Alaska, where the debris from four major landslides is easily distinguished from moraines and other supraglacial material. A series of aerial and satellite photos from 1972 to 2000 and field observations in 2001 and 2002 indicate that three of four landslides have fallen onto the surface of the glacier since about 1978. The landslides, which originated from the steeply dipping (60,70°) bedrock walls, were deposited onto the glacier in the ablation zone and are currently being transported downstream supraglacially. Individual glacial valleys with topographic relief of ,400 m are cut into high-grade metamorphic rock characterized by a steep north-dipping foliation and fractured by numerous large joints. Measurements of landslide area and average thickness obtained from high-resolution survey data indicate a total landslide volume of ,2·3 × 105 m3. This volume suggests a basin-averaged erosion rate from landslides of 0·48 mm a,1. An overall basin-scale erosion rate of 0·7 to 1·7 mm a,1 can be inferred, but depends on the percentage of the total-basin sediment yield contributed by supraglacial sources. A mean rockwall retreat rate of 6·7 mm a,1 is calculated and is considerably higher than published rates, which range from 0·04 to 4·0 mm a,1. Controls on landslide generation include seismicity, freeze,thaw processes, topography, rock strength, and debuttressing. It is likely all of these factors contribute to failure, although the primary controls for the landslides in this study are thought to be rock strength and topography. The absence of landslides on ten of the eleven glaciers on this ridge is attributed to landslide magnitude,frequency relationships and short temporal scale of this study. Large-volume bedrock landslides (>100 000 m3) may have low frequency, occurring less than once in a 55-year time frame. Copyright © 2005 John Wiley & Sons, Ltd. [source] Fabrication and Characterization of DNA/QPVP-Os Redox-Active Multilayer FilmELECTROANALYSIS, Issue 23 2004Jianyun Liu Abstract Calf thymus DNA was immobilized on functionalized glassy carbon, gold and quartz substrates, respectively, by the layer-by-layer (LBL) assembly method with a polycation QPVP-Os, a quaternized poly(4-vinylpyridine) partially complexed with osmium bis(2,2,-bipyridine) as counterions. UV-visible absorption and surface plasmon resonance spectroscopy (SPR) showed that the resulting film was uniform with the average thickness 3.4,nm for one bilayer. Cyclic voltammetry (CV) showed that the total surface coverage of the polycations increases as each QPVP-Os/DNA bilayer added to the electrode surface, but the surface formal potential of Os-centered redox reaction shifts negatively, which is mainly attributed to the intercalation of redox-active complex to DNA chain. The electron transfer kinetics of electroactive QPVP-Os in the multilayer film was investigated by electrochemical impedance experiment for the first time. The permeability of Fe(CN) in the solution into the multilayer film depends on the number of bilayers in the film. It is worth noting that when the multilayer film is up to 4 bilayers, the CV curves of the multilayer films display the typical characteristic of a microelectrode array. The nanoporous structure of the multilayer film was further confirmed by the surface morphology analysis using atomic force microscopy (AFM). [source] Controlled Synthesis of Cobalt Flowerlike Architectures by a Facile Hydrothermal RouteEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2008Ya-jing Zhang Abstract Cobalt flowerlike architectures composed of hexagonal nanoplatelets have been synthesized by a simple hydrothermal reduction method. The architectures are fabricated by the reaction of CoCl2 with NaOH at 140,180 °C in the presence of sodium dodecyl benzenesulfonate (SDBS), with NaH2PO2·H2O as reducing agent. The diameters of the flowers range from 8 to 10 ,m, and the average thickness of the hexagonal sheets is about 100 nm. Higher reaction temperatures and the proper concentration of sodium hydroxide (NaOH) are key requirements for the fabrication of the flowerlike architectures. A growth mechanism for these architectures is proposed on the basis of the characterization by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The magnetic hysteresis loops at 5 K and 295 K of the cobalt flowerlike architectures show ferromagnetic characteristics with coercivities of 371 Oe and 197 Oe, respectively. Our work may shed light on the designed fabrication of complex 3D architectures of other materials.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Geophysical exploration for interlayer slip breccia gold deposits: example from Pengjiakuang gold deposit, Shandong Province, ChinaGEOPHYSICAL PROSPECTING, Issue 2 2004Z. Qingdong ABSTRACT Interlayer slipping breccia-type gold deposit , a new type of gold deposit, defined recently in the northern margin of the Jiaolai Basin, Shandong Province, China , occurs in interlayer slip faults distributed along the basin margin. It has the features of large orebody thickness (ranging from 14 m to 46 m, with an average thickness of 30 m), shallow embedding (0,50 m thickness of cover), low tenor of gold ore (ranging from 3 g/t to 5 g/t), easy mining and ore dressing. This type of gold deposit has promising metallogenic forecasting and potential for economic exploitation. A ground gamma-ray survey in the Pengjiakuang gold-ore district indicates that the potassium/thorium ratio is closely related to the mineralization intensity, i.e. the larger the potassium/thorium ratio, the higher the mineralization. The gold mineralized alteration zone was defined by a potassium/thorium ratio of 0.35. A seismic survey confirms the location of the top and bottom boundaries and images various features within the Pengjiakuang gold mineralization belt. The gold-bearing shovel slipped belt dips to the south at an angle of 50,55° at the surface and 15,20° at depth. The seismic profile is interpreted in terms of a structural band on the seismic section characterized by a three-layered model. The upper layer is represented by weakly discontinuous reflections that represent the overlying conglomerates. A zone of stronger reflections representing the interlayer slip fault (gold-bearing mineralized zone) is imaged within the middle of the section, while the strongest reflections are in the lower part of the section and represent metamorphic rocks at depth. At the same time, the seismic reflection survey confirms the existence of a granite body at depth, indicating that ore-forming fluids may be related to the granite. A CSAMT survey showed that the gold-bearing mineralized zone is a conductive layer and contains a low-resistivity anomaly ranging from 2 ,m to 200 ,m. [source] Poly(1,3-propylene glycol-hexanedioic acid) grafted hydroxyl multiwall carbon nanotubesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Qing-Jie Meng Abstract Poly(1,3-propylene glycol-hexanedioic acid) grafted hydroxyl multiwall carbon nanotube (PHHCNT) was fabricated in the presence of butyl titanate using 1,3-propylene glycol, hexanedioic acid, and hydroxyl multiwall carbon nanotubes as reactants. The hydroxyl groups at carbon nanotubes reacted with hexanedioic acid and a small amount of carboxyl groups reacted with 1,3-propylene glycol, resulting in the PGHA grafted on the carbon nanotubes. The carbon nanotubes surrounded by the PGHA chains with an average thickness of , 2 nm. The polycondensation reactions can be controlled by the feed contents of HCNTs and the catalyst concentration in the reactants. The content of HCNTs in PHHCNT rises with an increase of the feed contents of HCNTs. In addition, the content of HCNTs in PHHCNT is higher than the feed contents of HCNTs in the reactants. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source] Synthesis and characterization of catalytic nanoporous carbon membranesAICHE JOURNAL, Issue 1 2001Michael S. Strano A method is reported for the synthesis of nobel catalyic nanoporous carbon membranes. Defect-free, nanoporous carbon films of 12.5,,m average thickness containing a dispersion of Ptx were synthesized on macroporous stainless-steel supports. Ideal gas selectivities for the catalytic membranes were simliar to those of inert nanoporous carbon membranes with He,N2=58.6 and O2N2=4.9. The selective hydrogenation of monoolefins (propylen, l-buiene, isobutylene) was used to probe the shape-selective catalytic proerties nad the transport selectivities of the membranes. The results were modeled using the linear regime of coupled sdsorption, transport and rection in the membrane. Model regression yielded 14.9, 19.7. and 18.4 kJ/mol for the activation energies of permeation for propylene, isobutylene, and l-butene, respectively. The system demonstrated selective reaction and transport favoring propane production with selectiveity ratios of 28.9:3.2.I for propane:n-butane:isobutane at 125°C. [source] Carbon-nitrogen-phosphorus removal and biofilm growth characteristics in an integrated wastewater treatment system involving a rotating biological contactorASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Angelo H. Cabije Abstract A new rotating biological contactor-packed media technology (RBC-PMT) is locally innovated using light polyethylene Amazon screen material as disc media. A single-stage co-current fed of this type, which is connected with a series of equalization tanks as an integrated wastewater treatment system (IWWTS), showed good carbon-nitrogen-phosphorus (C-N-P) removal and unveiled biofilm growth characteristics noteworthy for treating pollutants in wastewater. The equalization tanks approached facultative anaerobic conditions while the RBC-PMT exhibited a completely aerated system, both with a slightly alkaline pH, whose temperatures are ranging from 21 to 24 °C, and both performed as biological nutrient removal systems. The combined nutrient removal efficiency at high organic loading rate (HOLR) and low organic loading rate (LOLR) showed fair chemical oxygen demand (COD) removal at 65.68 and 67.89%, respectively. Nitrate-nitrogen removal demonstrated good removal at 79.17% at HOLR and 83.43% at LOLR. There was excellent phosphate-phosphorus removal determined at 91.64 and 94.35% at high and low OLRs, respectively. This indicates that increasing the organic loading rate decreases the C-N-P removal in the IWWTS. Biofilm growth was characterized by the selection and survival of microorganisms present under aerobic environmental conditions in the RBC-PMT system and their respective metabolism in removing C-N-P substrates. Yeasts, coliform bacteria particularly E. coli, Cyanobacteria, and benthic diatoms were dominant microorganisms found upon oil-immersion microscopy. Protozoans and algae including Chlorococcum, Chlorella, Diatoma, Tribonema, Oscillatoria, Euglena, and other motile rotifiers were also dominantly found in the biofilm samples. Biofilm growth is observed and its average thickness was measured to be 7.71 µm at HOLR and 2.81 µm at LOLR. Thicker biofilm at HOLR has caused the reduced rate of diffusion of the microorganisms and their metabolic products as manifested by the low C-N-P removal during HOLR. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Selective sweat gland removal with minimal skin excision in the treatment of axillary hyperhidrosis: a retrospective clinical and histological review of 15 patientsBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2006C.M. Lawrence Summary Background, Limited axillary skin excision and selective sweat gland removal from adjacent skin (Shelley's procedure) is currently rarely used for hyperhidrosis. Objectives, To determine whether this technique is a good way of permanently reducing axillary sweating. Methods, This was a prospective, open, nonrandomized trial of the therapy, conducted in a university dermatology department. A small skin ellipse, parallel to the skin crease lines, was excised from the centre of the area of maximal sweating. The wound edges were undermined to the extent of maximal sweating and the skin reflected. Large visible sweat glands attached to the undersurface of the adjacent skin could be readily identified and were snipped off using scissors. We treated 15 axillae in eight patients with axillary hyperhidrosis. Sweat reduction was assessed by the patients who estimated the percentage reduction in sweating postoperatively. The scar appearance was graded by the surgeon. Haematoxylin and eosin-stained transverse sections of eight axillary skin ellipses from five subjects were examined histologically to establish the size, position and depth of the sweat gland tissue. Results, All of the patients responded to treatment: mean sweat reduction was 65% (range 40,90%). Mean follow up was 1·3 years (range 0·1,6) and sweat reduction was maintained over this period. Histological material was available from five patients: sweat glands lay slightly deeper than hair follicles; glandular tissue occupied an average thickness of 3·5 mm in the 5-mm thick piece of skin. Apocrine gland lobules were more numerous and larger than eccrine gland lobules. Both gland types were in close apposition and did not occupy distinctly different depths within the skin. Conclusions, Local surgery using limited axillary skin excision and selective sweat gland removal remains one of the safest ways of permanently reducing axillary sweating. [source] A high-resolution relative time scale for the Viséan Stage (Carboniferous) of the Kulm Basin (Rhenish Mountains, Germany)GEOLOGICAL JOURNAL, Issue 3 2009Dieter Korn Abstract The Viséan (Carboniferous) sedimentary succession of the basinal Kulm facies (Rhenish Mountains) was investigated in detail in order to achieve a high-resolution stratigraphic subdivision and correlation. Additionally, the ranges of fossil index taxa (ammonoids), fossil marker beds, volcaniclastic horizons and sedimentary features (e.g. colour changes) were integrated in the correlation. As a result, a comprehensive database was compiled, which contains 190 stratigraphic events of the Viséan interval of this area. Several sections are almost completely composed of shales, which are regarded to represent a slow but constant basinal background sedimentation of the Kulm facies. The thickness of lithological homogeneous sections thus indicates an approximately linear record of time and the average thicknesses of biozones and positions of stratigraphic events can easily be calculated from the compiled database. The result is an approximately time-linear biostratigraphic scale for the Viséan Stage of the Kulm Basin. Given a numerical length of the Viséan Stage of ca. 19,Ma, 190 stratigraphic events give a mean resolution of 100,000 years. This is unique in Palaeozoic stratigraphy. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||||||||