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Enhanced electrogastrography: A realistic way to salvage a promise that was never kept?

world Journal of Gastroenterology 2017年第25期23卷 4517-4528页

作者： Michael d Poscente martin P Mintchev department of Electrical and Computer Engineering University of Calgary

To enhance the clinical utility of electrogastrography (EGG), which has been recorded since 1922, but is clinically unutilized. METHOdSAn innovative method to salvage the promise of EGG is proposed by introducing a preliminary procedure, while maintaining the electrodes, standardized equipment, and signal processing utilized in the well-established EGG testing of today. The proposed enhanced EGG (EEGG) protocol involves swallowing an ingestible capsule containing miniature electronic oscillator embedded in an expandable, self-disintegratable, biocompatible pseudobesoar residing in the stomach for the duration of the test. The benefits of the proposed approach are outlined, tested and discussed in details. RESULTSExperiments were performed on eight mongrel dogs (6F, 4M, 23.8 ± 3.3 kg). Four were administered an active EEGG capsule, while the rest were given a deactivated (battery removed) capsule. Pharmacologically facilitated gastric motility revealed a significant (P ween gastric motility indices obtained by force transducers implanted directly on the stomach, and the motility indices obtained by EEGG. A particular emphasis was made on preserving standard EGG-related hardware and software in order to facilitate the introduction of the proposed EEGG in environments which already utilize standard EGG testing. The expanded intragastric pseudobezoar containing the miniature electronic oscillator was retained during the tests, and could be disintegrated on demand. CONCLUSIONEnhancing standard EGG by an ingestible, self-expanding and self-disintegrating pseudobesoar containing a miniature electronic oscillator can be an important avenue for clinical applicability of this test.

关键词： Electrogastrography Functional dyspepsia Gastroparesis Ingestible oscillator Pseudobesoar

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Seamless and non-repetitive 4d texture variation synthesis and real-time rendering for measured optical material behavior

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Computational Visual Media 2019年第2期5卷 161-170页

作者： martin Ritz Simon Breitfelder Pedro Santos Arjan Kuijper dieter w. Fellner Fraunhofer IGd Darmstadt64283Germany TU darmstadt Darmstadt64289Germany TU Graz Graz8010Austria

we show how to overcome the single weakness of an existing fully automatic system for acquisition of spatially varying optical material behavior of real object surfaces. while the expression of spatially varying material behavior with spherical dependence on incoming light as a 4d texture(an ABTF material model) allows flexible mapping onto arbitrary 3d geometry, with photo-realistic rendering and interaction in real time,this very method of texture-like representation exposes it to common problems of texturing, striking in two disadvantages. Firstly, non-seamless textures create visible artifacts at boundaries. Secondly, even a perfectly seamless texture causes repetition artifacts due to their organised placement in large numbers over a 3d surface. we have solved both problems through our novel texture synthesis method that generates a set of seamless texture variations randomly distributed over the surface at shading time. when compared to regular 2d textures, the inter-dimensional coherence of the 4d ABTF material model poses entirely new challenges to texture synthesis, which includes maintaining the consistency of material behavior throughout the 4d space spanned by the spatial image domain and the angular illumination hemisphere. In addition, we tackle the increased memory consumption caused by the numerous variations through a fitting scheme specifically designed to reconstruct the most prominent effects captured in the material model.

关键词： optical material behavior reflectance modeling 4d texture synthesis texturing

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Successful endoscopic treatment of colonic gallstone ileus using electrohydraulic lithotripsy

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world Journal of Gastroenterology 2010年第12期16卷 1533-1536页

作者： martin d Zielinski Lincoln E Ferreira Todd H Baron division of Trauma Critical Care and General Surgery department of Medicine Federal University of Juiz de Fora department of Gastroenterology and Hepatology

The surgical management of gallstone ileus is complex and potentially highly *** management requires enterolithotomy and is generally followed by fistula resection at a later *** have been reports of gallstone extraction using various endoscopic modalities to relieve the obstruction,however,to date,there has never been a published case of endoscopic stone extraction from the colon using electrohydraulic *** this report,we present the technique employed to successfully perform an electrohydraulic lithotripsy for removal of a large gallstone impacted in the sigmoid colon.A cavity was excavated in an obstructing 4.1 cm lamellated stone in the sigmoid colon using electrohydraulic lithotripsy.A screw stent retractor and stent extractor bored a larger lumen which allowed for guidewire advancement and stone fracture via serial pneumatic balloon *** stone fragments were *** lithotripsy is a safe and effective method to treat colonic obstruction in the setting of gallstone ileus.

关键词： Gallstone ileus Endoscopy Electrohydraulic lithotripsy Bowel obstruction Colon

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direct LEd writing of submicron resist patterns： Towards the fabrication of individually-addressable InGaN sub-micron stripe-shaped LEd arrays

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Nano Research 2014年第12期7卷 1849-1860页

作者： Zheng Gong Benoit Guilhabert Zhitao Chen martin d. dawson Institute of Photonics University of Strathclyde Wolfson Centre 106 Rottenrow Glasgow G40NW UK Guangdong General Research Institute for Industrial Technology 363 Changxin Road Tianhe District Guangzhou 510650 China

Submicron stripe-shaped InGaN light-emitting diode （LEd） arrays with individually addressable capabilities are demonstrated. The critical submicron- stripe metallic electrodes, which define the emission pattern, are formed by direct LEd writing in a mask-free manner. The individually addressable submicron-stripe LEds show excellent performance in terms of their electrical characteristics （with typical turn-on voltage of 3 V, operational stability and power output up to 28 ~w at 3 mA）. Unlike conventional broad-sized LEds, the efficiency droop of the submicron-stripe LEd is significantly suppressed--in fact, there is no efficiency droop for current densities up to 100 A/cm^2. Furthermore, the submicron-stripe LEd shows a lower temperature-dependent shift of the emission wavelength. The lateral emission width is increased with increasing injection current, resulting in a wider lateral emission size than the metallic submicron-stripe electrode. The underlying physics of these phenomena are analysed. Such submicron-stripe LEd arrays open up promising applications in nanophotonics and bio-sensing.

关键词： direct writing light-emitting diodes electroluminescence efficiency droop mask-free lithography

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Comparative analysis of different static mixers performance by CFd technique:An innovative mixer

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Chinese Journal of Chemical Engineering 2020年第3期28卷 672-684页

作者： M.M.Haddadi S.H.Hosseini d.Rashtchian martin Olazar Chemical and Petroleum Engineering department Sharif University of TechnologyTehranIran department of Chemical Engineering.Ilam University llam 69315-516Iran department of Chemical Engineering University of the Basque Country(UPV/EHU)Sarriena s/nLeioaSpain

The flow and mixing behavior of two miscible liquids has been studied in an innovative static mixer by using CFd,with Reynolds numbers ranging from 20 to *** performance of the new mixer is compared with those of Kenics,SMX,and Komax static *** pressure drop ratio(Z-factor),coefficient of variation(CoV),and extensional efficiency(α)features have been used to evaluate power consumption,distributive mixing,and dispersive mixing performances,respectively,in all *** model is firstly validated based on experimental data measured for the pressure drop ratio and the coefficient of *** results are consistent with measured data and those obtained by available correlations in the *** new mixer shows a superior mixing performance compared to the other mixers.

关键词： CFd New static mixer Coefficient of variation Pressure drop ratio

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Fracture initiation and propagation in intact rock—A review

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Journal of Rock Mechanics and Geotechnical Engineering 2014年第4期6卷 287-300页

作者： E.Hoek C.d.martin west Vancouver British Columbia V7V 0B3 Canada department of Civil & Environmental Engineering University of Alberta Edmonton Alberta T6G 2W2 Canada

The initiation and propagation of failure in intact rock are a matter of fundamental importance in rock engineering. At low confining pressures, tensile fracturing initiates in samples at 40%-60% of the uniaxial compressive strength and as loading continues, and these tensile fractures increase in density, ultimately coalescing and leading to strain localization and macro-scale shear failure of the samples. The Griffith theory of brittle failure provides a simplified model and a useful basis for discussion of this process. The Hoek-Brown failure criterion provides an acceptable estimate of the peak strength for shear failure but a cutoff has been added for tensile conditions. However, neither of these criteria adequately explains the progressive coalition of tensile cracks and the final shearing of the specimens at higher confining stresses. Grain-based numerical models, in which the grain size distributions as well as the physical properties of the component grains of the rock are incorporated, have proved to be very useful in studying these more complex fracture processes.

关键词： Tensile failure Crack propagation Griffith theory Hoek-Brown criterion Tension cutoff Crack coalescence Numerical models

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A numerical investigation into key factors controlling hard rock excavation via electropulse stimulation

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第4期12卷 793-801页

作者： daniel Vogler Stuart dCwalsh martin OSaar Geothermal Energy and Geofluids Institute of GeophysicsETH ZurichZurichSwitzerland department of Civil Engineering Monash UniversityMelbourneAustralia department of Earth and Environmental Sciences University of MinnesotaMinneapolisUSA

Electropulse stimulation provides an energy-efficient means of excavating hard rocks through repeated application of high voltage pulses to the rock *** such,it has the potential to confer significant advantages to mining and drilling operations for mineral and energy ***,before these benefits can be realized,a better understanding of these processes is required to improve their deployment in the *** this paper,we employ a recently developed model of the grain-scale processes involved in electropulse stimulation to examine excavation of hard rock under realistic operating *** that end,we investigate the maximum applied voltage within ranges of 120e600 kV,to observe the onset of rock *** further study the effect of grain size on rock breakage,by comparing fine(granodiorite)and coarse grained(granite)***,the pore fluid salinity is investigated,since the electric conductivity of the pore fluid is shown to be a governing factor for the electrical conductivity of the modeled *** study demonstrates that all investigated factors are crucial to the efficiency of rock fragmentation by electropulsing.

关键词： Electropulse stimulation High voltage breakdown Numerical modeling drilling Thermo-mechanics

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Bacterial Sample Concentration and Culture Monitoring Using a PEG-Based Osmotic System with Inline Impedance and Voltammetry Measurements

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Journal of Analysis and Testing 2019年第2期3卷 166-174页

作者： martin K.Kimani John Mwangi Edgar d.Goluch department of Chemical Engineering Northeastern UniversityBostonMA 02115USA department of Bioengineering Northeastern UniversityBostonMA 02115USA

Impedance measurements using graphite electrodes were used to detect the increase in culture medium conductivity due to bacteria growth in real time along with simultaneous voltammetric monitoring of pyocyanin *** methods were compared to conventional continuous monitoring of bacterial cultures using turbidity measurement at an optical density of 600 nm(Od600).A practical osmotic system was further designed for concentrating bacterial cultures during growth to enable earlier detection using the electrochemical *** cultures,starting from an initial culture density of 1×10^(8) cells/mL,were grown inside a sealed cellulose ester dialysis membrane,while polyethylene glycol in LB medium was used as the draw solution outside the membrane to gradually concentrate the growing cultures.0.7-mm-diameter graphite for mechanical pencils was utilized as working and counter electrodes with a platinum wire reference electrode for electrochemical measurements with and without the osmotic *** the absence of forward osmosis,impedance meas-urements detected culture growth~1 h faster than conventional *** osmosis showed a twofold decrease in the time to detect pyocyanin production as an indicator for bacterial *** impedance monitoring,removal of water by osmosis was conflated with the impedance decrease due to cell growth;however,the results show a promising ability to detect bacteria growth via an observed shift in osmotic impedance profile when bacteria are present in a *** monitoring the deviation in the impedance profile,a threefold improvement in detection time was achieved when compared to conventional Od600 measurements.

关键词： Osmotic concentration Pseudomonas aeruginosa Bacterial growth detection Impedance electrochemical monitoring Forward osmosis

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Honeycomb-like MXene/NiFeP_(x)–NC with“continuous”single-crystal enabling high activity and robust durability in electrocatalytic oxygen evolution reactions

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Journal of Advanced Ceramics 2023年第3期12卷 553-564页

作者： Xiaojun Zeng Yifei Ye Yongqing wang Ronghai Yu martin Moskovits Galen d.Stucky Advanced Ceramic Materials Research Institute School of Materials Science and EngineeringJingdezhen Ceramic UniversityJingdezhen 333403China School of Materials Science and Engineering Beihang UniversityBeijing 100191China department of Chemistry and Biochemistry University of California Santa BarbaraCA 93106USA

The development of low-cost,stable,and robust non-noble metal catalysts for water oxidation is a pivotal challenge for sustainable hydrogen production through electrocatalytic water ***,such catalysts suffer from high overpotential and sluggish kinetics in oxygen evolution reactions(OERs).Herein,we report a“continuous”single-crystal honeycomb-like MXene/NiFeP_(x)–N-doped carbon(NC)heterostructure,in which ultrasmall NiFeP_(x)nanoparticles(NPs)encapsulated in the NC are tightly anchored on a layered ***,this MXene/NiFeP_(x)–NC delivers outstanding OER catalytic performance,which stems from“continuous”single-crystal characteristics,abundant active sites derived from the ultrasmall NiFeP_(x)NPs,and the stable honeycomb-like heterostructure with an open *** experimental results are rationalized theoretically(by density functional theory(dFT)calculations),which suggests that it is the unique MXene/NiFeP_(x)–NC heterostructure that promotes the sluggish OER,thereby enabling superior durability and excellent activity with an ultralow overpotential of 240 mV at a current density of 10 mA×cm^(−2).

关键词： layered MXene ultrasmall NiFePx nanoparticles(NPs) “continuous”single-crystal honeycomb-like heterostructure oxygen evolution reaction(OER)activity

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Plant xylem hydraulics:what we understand,current research,and future challenges

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Journal of Integrative Plant Biology 2017年第6期59卷 356-389页

作者： martin d. Venturas John S. Sperry Uwe G. Hacke department of Biology University of Utah257 S 1400ESalt Lake CityUT 84112USA department of Renewable Resources University of AlbertaEdmontonAB T6G 2E3Canada

Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. we explain the physics of water transport in plants and the limits of this transport system, highlighting the relationships between xylem structure and function. we describe the great variety of techniques existing for evaluating xylem resistance to cavitation. we address several methodological issues and their connec- tion with current debates on conduit refilling and exponentially shaped vulnerability curves. we analyze the trade-offs existing between water transport safety and efficiency. we also stress how little information is available on molecular biology of cavitation and the potential role of aquaporins in conduit refilling. Finally, we draw attention to how plant hydraulic traits can be used for modeling stomatal responses to environmental variables and climate change, including drought mortality.

关键词： william J. Lucas, University of California, davis, USAReceived Jan. 10,2017 Accepted Mar. 9,2017 Online on Mar. 14,2017

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