Flexible metal-semiconductor-metal device prototype on wafer-scale thick boron nitride layers grown by MOVPE.

PubMed

Li, Xin; Jordan, Matthew B; Ayari, Taha; Sundaram, Suresh; El Gmili, Youssef; Alam, Saiful; Alam, Muhbub; Patriarche, Gilles; Voss, Paul L; Paul Salvestrini, Jean; Ougazzaden, Abdallah

2017-04-11

Practical boron nitride (BN) detector applications will require uniform materials over large surface area and thick BN layers. To report important progress toward these technological requirements, 1~2.5 µm-thick BN layers were grown on 2-inch sapphire substrates by metal-organic vapor phase epitaxy (MOVPE). The structural and optical properties were carefully characterized and discussed. The thick layers exhibited strong band-edge absorption near 215 nm. A highly oriented two-dimensional h-BN structure was formed at the film/sapphire interface, which permitted an effective exfoliation of the thick BN film onto other adhesive supports. And this structure resulted in a metal-semiconductor-metal (MSM) device prototype fabricated on BN membrane delaminating from the substrate. MSM photodiode prototype showed low dark current of 2 nA under 100 V, and 100 ± 20% photoconductivity yield for deep UV light illumination. These wafer-scale MOVPE-grown thick BN layers present great potential for the development of deep UV photodetection applications, and even for flexible (opto-) electronics in the future.

Localization-delocalization transition of electrons at the percolation threshold of semiconductor GaAs1-xNx alloys: The appearance of a mobility edge

NASA Astrophysics Data System (ADS)

Alberi, K.; Fluegel, B.; Beaton, D. A.; Ptak, A. J.; Mascarenhas, A.

2012-07-01

Electrons in semiconductor alloys have generally been described in terms of Bloch states that evolve from constructive interference of electron waves scattering from perfectly periodic potentials, despite the loss of structural periodicity that occurs on alloying. Using the semiconductor alloy GaAs1-xNx as a prototype, we demonstrate a localized to delocalized transition of the electronic states at a percolation threshold, the emergence of a mobility edge, and the onset of an abrupt perturbation to the host GaAs electronic structure, shedding light on the evolution of electronic structure in these abnormal alloys.

Combined VIS-IR spectrometer with vertical probe beam

NASA Astrophysics Data System (ADS)

Protopopov, V.

2017-12-01

A prototype of a combined visible-infrared spectrometer with a vertical probe beam is designed and tested. The combined spectral range is 0.4-20 μ with spatial resolution 1 mm. Basic features include the ability to measure both visibly transparent and opaque substances, as well as buried structures, such as in semiconductor industry; horizontal orientation of a sample, including semiconductor wafers; and reflection mode of operation, delivering twice the sensitivity compared to the transmission mode.

Self-passivation rule and structure of CdTe Σ3 (112) grain boundaries

NASA Astrophysics Data System (ADS)

Liu, Cheng-yan; Zhang, Yue-yu; Hou, Yu-sheng; Chen, Shi-you; Xiang, Hong-jun; Gong, Xin-gao

2016-05-01

The theoretical study of grain boundaries (GBs) in polycrystalline semiconductors is currently stalemated by their complicated nature, which is difficult to extract from any direct experimental characterization. Usually, coincidence-site-lattice models are constructed simply by aligning two symmetric planes ignoring various possible reconstructions. Here, we propose a general self-passivation rule to determine the low-energy GB reconstruction and find new configurations for the CdTe Σ3 (112) GBs. First-principles calculations show that it has lower formation energies than the prototype GBs adopted widely in previous studies. Surprisingly, the reconstructed GBs show self-passivated electronic properties without deep-level states in the band gap. Based on the reconstructed configurations, we revisited the influence of CdC l2 post-treatment on the CdTe GBs and found that the addition of both Cd and Cl atoms in the GB improves the photovoltaic properties by promoting self-passivation and inducing n -type levels, respectively. The present study provides a new route for further studies of GBs in covalent polycrystalline semiconductors and highlights that previous studies on the GBs of multinary semiconductors, which are based on the unreconstructed prototype GB models, should be revisited.

Solar Energy Research Facility | Photovoltaic Research | NREL

Science.gov Websites

-efficiency crystalline solar cells. Laboratories in the center module are used to fabricate prototype solar cells and analyze the semiconductor material used to make solar cells, as well as to research hydrogen

Microplasma fabrication: from semiconductor technology for 2D-chips and microfluidic channels to rapid prototyping and 3D-printing of microplasma devices

NASA Astrophysics Data System (ADS)

Shatford, R.; Karanassios, Vassili

2014-05-01

Microplasmas are receiving attention in recent conferences and current scientific literature. In our laboratory, microplasmas-on-chips proved to be particularly attractive. The 2D- and 3D-chips we developed became hybrid because they were fitted with a quartz plate (quartz was used due to its transparency to UV). Fabrication of 2D- and 3D-chips for microplasma research is described. The fabrication methods described ranged from semiconductor fabrication technology, to Computer Numerical Control (CNC) machining, to 3D-printing. These methods may prove to be useful for those contemplating in entering microplasma research but have no access to expensive semiconductor fabrication equipment.

Localization-delocalization transition of electrons at the percolation threshold of semiconductor GaAs 1–xN x alloys: The appearance of a mobility edge

DOE PAGES

Alberi, K.; Fluegel, B.; Beaton, D. A.; ...

2012-07-09

Electrons in semiconductor alloys have generally been described in terms of Bloch states that evolve from constructive interference of electron waves scattering from perfectly periodic potentials, despite the loss of structural periodicity that occurs on alloying. Using the semiconductor alloy GaAs₁₋ xN x as a prototype, we demonstrate a localized to delocalized transition of the electronic states at a percolation threshold, the emergence of a mobility edge, and the onset of an abrupt perturbation to the host GaAs electronic structure, shedding light on the evolution of electronic structure in these abnormal alloys.

Efficiency of depleted UO2 based semiconductor neutron detectors in direct and indirect configuration—A GEANT4 simulation study

NASA Astrophysics Data System (ADS)

Parida, M. K.; Prabakar, K.; Sundari, S. T.

2018-03-01

In the present work, Monte Carlo simulations using GEANT4 are carried out to estimate the efficiency of semiconductor neutron detectors with depleted UO2 (DUO2) as converter material, in both planar (direct and indirect) and 3D geometry (cylindrical perforation and trenches structure) configurations. The simulations were conducted for neutrons of variable energy viz., thermal (25 meV) and fast (1 to 10 MeV) that were incident on varying thicknesses (0.25 μm to 1000 μm), diameters (1 μm to 9 μm) and widths (1 μm to 9 μm) along with depths (50 μm to 275 μm) of DUO2 for planar, cylindrical perforated and trench structures, respectively. In the case of direct planar detectors, efficiency was found to increase with the thickness of DUO2 and the rate at which efficiency increased was found to follow the macroscopic fission cross section at the corresponding neutron energy. In the case of indirect planar detector, efficiency was lower as compared to direct configuration and was found to saturate beyond a thickness of ~3 μm. This saturation is explained on the basis of mean free path of neutrons in the DUO2 material. For the 3D perforated silicon detectors of cylindrical (trench) geometry, backfilled with DUO2, the efficiency for detection of thermal neutrons ~25 meV and fast neutrons ~ typical energy of 10 MeV was found to be ~0.0159% (~0.0177%) and ~0.0088% (0.0098%), respectively. These efficiency values were two (one) order values higher than planar indirect detector for thermal (fast) neutrons. Histogram plots were also obtained from the GEANT4 simulations to monitor the energy distribution of fission products in planar (direct and indirect) and 3D geometry (cylindrical and trench) configurations. These plots revealed that, for all the detector configurations, the energy deposited by the fission products are higher as compared to the typical gamma ray background. Thus, for detectors with DUO2 as converter material, higher values of low level discriminator (LLD) can be set, so as to achieve good background discrimination.

The Si/CdTe semiconductor Compton camera of the ASTRO-H Soft Gamma-ray Detector (SGD)

NASA Astrophysics Data System (ADS)

Watanabe, Shin; Tajima, Hiroyasu; Fukazawa, Yasushi; Ichinohe, Yuto; Takeda, Shin`ichiro; Enoto, Teruaki; Fukuyama, Taro; Furui, Shunya; Genba, Kei; Hagino, Kouichi; Harayama, Atsushi; Kuroda, Yoshikatsu; Matsuura, Daisuke; Nakamura, Ryo; Nakazawa, Kazuhiro; Noda, Hirofumi; Odaka, Hirokazu; Ohta, Masayuki; Onishi, Mitsunobu; Saito, Shinya; Sato, Goro; Sato, Tamotsu; Takahashi, Tadayuki; Tanaka, Takaaki; Togo, Atsushi; Tomizuka, Shinji

2014-11-01

The Soft Gamma-ray Detector (SGD) is one of the instrument payloads onboard ASTRO-H, and will cover a wide energy band (60-600 keV) at a background level 10 times better than instruments currently in orbit. The SGD achieves low background by combining a Compton camera scheme with a narrow field-of-view active shield. The Compton camera in the SGD is realized as a hybrid semiconductor detector system which consists of silicon and cadmium telluride (CdTe) sensors. The design of the SGD Compton camera has been finalized and the final prototype, which has the same configuration as the flight model, has been fabricated for performance evaluation. The Compton camera has overall dimensions of 12 cm×12 cm×12 cm, consisting of 32 layers of Si pixel sensors and 8 layers of CdTe pixel sensors surrounded by 2 layers of CdTe pixel sensors. The detection efficiency of the Compton camera reaches about 15% and 3% for 100 keV and 511 keV gamma rays, respectively. The pixel pitch of the Si and CdTe sensors is 3.2 mm, and the signals from all 13,312 pixels are processed by 208 ASICs developed for the SGD. Good energy resolution is afforded by semiconductor sensors and low noise ASICs, and the obtained energy resolutions with the prototype Si and CdTe pixel sensors are 1.0-2.0 keV (FWHM) at 60 keV and 1.6-2.5 keV (FWHM) at 122 keV, respectively. This results in good background rejection capability due to better constraints on Compton kinematics. Compton camera energy resolutions achieved with the final prototype are 6.3 keV (FWHM) at 356 keV and 10.5 keV (FWHM) at 662 keV, which satisfy the instrument requirements for the SGD Compton camera (better than 2%). Moreover, a low intrinsic background has been confirmed by the background measurement with the final prototype.

A multi-level rapid prototyping drill guide template reduces the perforation risk of pedicle screw placement in the lumbar and sacral spine.

PubMed

Merc, Matjaz; Drstvensek, Igor; Vogrin, Matjaz; Brajlih, Tomaz; Recnik, Gregor

2013-07-01

The method of free-hand pedicle screw placement is generally safe although it carries potential risks. For this reason, several highly accurate computer-assisted systems were developed and are currently on the market. However, these devices have certain disadvantages. We have developed a method of pedicle screw placement in the lumbar and sacral region using a multi-level drill guide template, created with the rapid prototyping technology and have validated it in a clinical study. The aim of the study was to manufacture and evaluate the accuracy of a multi-level drill guide template for lumbar and first sacral pedicle screw placement and to compare it with the free-hand technique under fluoroscopy supervision. In 2011 and 2012, a randomized clinical trial was performed on 20 patients. 54 screws were implanted in the trial group using templates and 54 in the control group using the fluoroscopy-supervised free-hand technique. Furthermore, applicability for the first sacral level was tested. Preoperative CT-scans were taken and templates were designed using the selective laser sintering method. Postoperative evaluation and statistical analysis of pedicle violation, displacement, screw length and deviation were performed for both groups. The incidence of cortex perforation was significantly reduced in the template group; likewise, the deviation and displacement level of screws in the sagittal plane. In both groups there was no significantly important difference in deviation and displacement level in the transversal plane as not in pedicle screw length. The results for the first sacral level resembled the main investigated group. The method significantly lowers the incidence of cortex perforation and is therefore potentially applicable in clinical practice, especially in some selected cases. The applied method, however, carries a potential for errors during manufacturing and practical usage and therefore still requires further improvements.

Cameras for semiconductor process control

NASA Technical Reports Server (NTRS)

Porter, W. A.; Parker, D. L.

1977-01-01

The application of X-ray topography to semiconductor process control is described, considering the novel features of the high speed camera and the difficulties associated with this technique. The most significant results on the effects of material defects on device performance are presented, including results obtained using wafers processed entirely within this institute. Defects were identified using the X-ray camera and correlations made with probe data. Also included are temperature dependent effects of material defects. Recent applications and improvements of X-ray topographs of silicon-on-sapphire and gallium arsenide are presented with a description of a real time TV system prototype and of the most recent vacuum chuck design. Discussion is included of our promotion of the use of the camera by various semiconductor manufacturers.

Defect-driven interfacial electronic structures at an organic/metal-oxide semiconductor heterojunction.

PubMed

Winget, Paul; Schirra, Laura K; Cornil, David; Li, Hong; Coropceanu, Veaceslav; Ndione, Paul F; Sigdel, Ajaya K; Ginley, David S; Berry, Joseph J; Shim, Jaewon; Kim, Hyungchui; Kippelen, Bernard; Brédas, Jean-Luc; Monti, Oliver L A

2014-07-16

The electronic structure of the hybrid interface between ZnO and the prototypical organic semiconductor PTCDI is investigated via a combination of ultraviolet and X-ray photoelectron spectroscopy (UPS/XPS) and density functional theory (DFT) calculations. The interfacial electronic interactions lead to a large interface dipole due to substantial charge transfer from ZnO to 3,4,9,10-perylenetetracarboxylicdiimide (PTCDI), which can be properly described only when accounting for surface defects that confer ZnO its n-type properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chip-scale fluorescence microscope based on a silo-filter complementary metal-oxide semiconductor image sensor.

PubMed

Ah Lee, Seung; Ou, Xiaoze; Lee, J Eugene; Yang, Changhuei

2013-06-01

We demonstrate a silo-filter (SF) complementary metal-oxide semiconductor (CMOS) image sensor for a chip-scale fluorescence microscope. The extruded pixel design with metal walls between neighboring pixels guides fluorescence emission through the thick absorptive filter to the photodiode of a pixel. Our prototype device achieves 13 μm resolution over a wide field of view (4.8 mm × 4.4 mm). We demonstrate bright-field and fluorescence longitudinal imaging of living cells in a compact, low-cost configuration.

Endoluminal perforation of a magnetic antireflux device.

PubMed

Bauer, Margit; Meining, Alexander; Kranzfelder, Michael; Jell, Alissa; Schirren, Rebekka; Wilhelm, Dirk; Friess, Helmut; Feussner, Hubertus

2015-12-01

The history of surgical antireflux treatment is coined by the search for better alternatives to Nissen fundoplication. Implantable devices are one option, beginning with the "Angelchik" prosthesis 30 years ago. However, this procedure was left soon because of the high rate of foreign body connected problems (migration, perforation). A modern approach is a magnetic sphincter augmentation device (LINX Reflux Management System, Torax Medical, Shoreview, MN, USA), a magnetic chain which is implanted laparoscopically. Advantages reported are simplicity to apply and good results in reflux control, with up to now only rare complication rates as reported in the literature (Lipham et al. in Dis Esophagus, 2014). We report one case of erosion of the esophagus by a LINX system resulting in severe dysphagia. A complete endoluminal removal could be achieved by a prototype OTSC-clip remover. Complete remission could be achieved. The technique is presented in detail (video). In principle, total endoscopic removal of the LINX device is feasible in case of major erosion.

Plasmonic hole arrays for combined photon and electron management

DOE PAGES

Liapis, Andreas C.; Sfeir, Matthew Y.; Black, Charles T.

2016-11-14

Material architectures that balance optical transparency and electrical conductivity are highly sought after for thin-film device applications. However, these are competing properties, since the electronic structure that gives rise to conductivity typically also leads to optical opacity. Nanostructured metal films that exhibit extraordinary optical transmission, while at the same time being electrically continuous, offer considerable flexibility in the design of their transparency and resistivity. In this paper, we present design guidelines for metal films perforated with arrays of nanometer-scale holes, discussing the consequences of the choice of nanostructure dimensions, of the type of metal, and of the underlying substrate onmore » their electrical, optical, and interfacial properties. We experimentally demonstrate that such films can be designed to have broad-band optical transparency while being an order of magnitude more conductive than indium tin oxide. Finally, prototypical photovoltaic devices constructed with perforated metal contacts convert ~18% of the incident photons, compared to <1% for identical devices having contacts without the hole array.« less

Feasibility of a semiconductor dosimeter to monitor skin dose in interventional radiology.

PubMed

Meyer, P; Regal, R; Jung, M; Siffert, P; Mertz, L; Constantinesco, A

2001-10-01

The design and preliminary test results of a semiconductor silicon dosimeter are presented in this article. Use of this dosimeter is foreseen for real-time skin dose control in interventional radiology. The strong energy dependence of this kind of radiation detector is well overcome by filtering the silicon diode. Here, the optimal filter features have been calculated by numerical Monte Carlo simulations. A prototype has been built and tested in a radiological facility. The first experimental results show a good match between the filtered semiconductor diode response and an ionization chamber response, within 2% fluctuation in a 2.2 to 4.1 mm Al half-value layer (HVL) energy range. Moreover, the semiconductor sensor response is linear from 0.02 Gy/min to at least 6.5 Gy/min, covering the whole dose rate range found in interventional radiology. The results show that a semiconductor dosimeter could be used to monitor skin dose during the majority of procedures using x-rays below 150 keV. The use of this device may assist in avoiding radiation-induced skin injuries and lower radiation levels during interventional procedures.

Continuum and atomistic description of excess electrons in TiO2

NASA Astrophysics Data System (ADS)

Maggio, Emanuele; Martsinovich, Natalia; Troisi, Alessandro

2016-02-01

The modelling of an excess electron in a semiconductor in a prototypical dye sensitised solar cell is carried out using two complementary approaches: atomistic simulation of the TiO2 nanoparticle surface is complemented by a dielectric continuum model of the solvent-semiconductor interface. The two methods are employed to characterise the bound (excitonic) states formed by the interaction of the electron in the semiconductor with a positive charge opposite the interface. Density-functional theory (DFT) calculations show that the excess electron in TiO2 in the presence of a counterion is not fully localised but extends laterally over a large region, larger than system sizes accessible to DFT calculations. The numerical description of the excess electron at the semiconductor-electrolyte interface based on the continuum model shows that the exciton is also delocalised over a large area: the exciton radius can have values from tens to hundreds of Ångströms, depending on the nature of the semiconductor (characterised by the dielectric constant and the electron effective mass in our model).

Endoscopic removal of over-the-scope clips using a novel cutting device: a retrospective case series.

PubMed

Schmidt, Arthur; Riecken, Bettina; Damm, Michael; Cahyadi, Oscar; Bauder, Markus; Caca, Karel

2014-09-01

Over-the-scope clips (OTSCs; Ovesco Endoscopy, Tübingen, Germany) are extensively used for treatment of gastrointestinal perforations, leakages, fistulas, and bleeding. In this report, a new method of removing OTSCs using a prototype bipolar cutting device is described. A total of 11 patients underwent endoscopic removal of an OTSC. The OTSC was cut at two opposing sites by a prototype device (DC ClipCutter; Ovesco Endoscopy). The remaining clip fragments were extracted using a standard forceps. Mean procedure time was 47 minutes (range 35 - 75 minutes). Cutting of the OTSC at two opposing sites was successful in all cases (100 %). Complete retrieval of all clip fragments was possible in 10 patients (91 %). The overall success rate for cutting and complete removal of the clip was 91 %. No major complications were observed. Removal of OTSCs with the prototype device was feasible and effective. The device may be valuable for OTSC removal in emergency as well as elective indications. © Georg Thieme Verlag KG Stuttgart · New York.

Vacancy effects on the electronic and structural properties pentacene

NASA Astrophysics Data System (ADS)

Laraib, Iflah; Janotti, Anderson

Defects in organic crystals are likely to affect charge transport in organic electronic devices. Vacancies can create lattice distortions and modify electronic states associated with the molecules in its surrounding. Spectroscopy experiments indicate that molecular vacancies trap charge carriers. Experimental characterization of individual defects is challenging and unambiguous. Here we use density functional calculations including van der Waals interactions in a supercell approach to study the single vacancy in pentacene, a prototype organic semiconductor. We determine formation energies, local lattice relaxations, and discuss how vacancies locally distort the lattice and affect the electronic properties of the host organic semiconductor.

A prototype portable breath acetone analyzer for monitoring fat loss.

PubMed

Toyooka, Tsuguyoshi; Hiyama, Satoshi; Yamada, Yuki

2013-09-01

Acetone contained in our exhaled breath is a metabolic product of the breakdown of body fat and is expected to be a good indicator of fat-burning. Typically, gas chromatography or mass spectrometry are used to measure low-concentration compounds in breath but such large instruments are not suitable for daily use by diet-conscious people. Here, we prototype a portable breath acetone analyzer that has two types of semiconductor-based gas sensors with different sensitivity characteristics, enabling the acetone concentration to be calculated while taking into account the presence of ethanol, hydrogen, and humidity. To investigate the accuracy of our prototype and its application in diet support, experiments were conducted on healthy adult volunteers. Breath acetone concentrations obtained from our prototype and from gas chromatography showed a strong correlation throughout the experiments. Moreover, body fat in subjects with a controlled caloric intake and taking exercise decreased significantly, whereas breath acetone concentrations in those subjects increased significantly. These results prove that our prototype is practical and useful for self-monitoring of fat-burning at home or outside. Our prototype will help to prevent and alleviate obesity and diabetes.

Gaseous Effluent Treatment Using a Pulsed Corona Discharge

DTIC Science & Technology

1995-07-01

Air Products and Chemicals , Inc . 7201...Warfare Center, Air Products and Chemicals , Inc ., and Southwest Research Institute have investigated the abatement efficacy of a prototype coaxial PCR...NF3," NF3 Environmental Task Force, Air Products and Chemicals , Inc ., 1993. 2) P. Burggraaf, "Process Exhaust Treatment," Semiconductor

Insight into doping efficiency of organic semiconductors from the analysis of the density of states in n-doped C60 and ZnPc

NASA Astrophysics Data System (ADS)

Gaul, Christopher; Hutsch, Sebastian; Schwarze, Martin; Schellhammer, Karl Sebastian; Bussolotti, Fabio; Kera, Satoshi; Cuniberti, Gianaurelio; Leo, Karl; Ortmann, Frank

2018-05-01

Doping plays a crucial role in semiconductor physics, with n-doping being controlled by the ionization energy of the impurity relative to the conduction band edge. In organic semiconductors, efficient doping is dominated by various effects that are currently not well understood. Here, we simulate and experimentally measure, with direct and inverse photoemission spectroscopy, the density of states and the Fermi level position of the prototypical materials C60 and zinc phthalocyanine n-doped with highly efficient benzimidazoline radicals (2-Cyc-DMBI). We study the role of doping-induced gap states, and, in particular, of the difference Δ1 between the electron affinity of the undoped material and the ionization potential of its doped counterpart. We show that this parameter is critical for the generation of free carriers and influences the conductivity of the doped films. Tuning of Δ1 may provide alternative strategies to optimize the electronic properties of organic semiconductors.

Electrical Properties of Reactive Liquid Crystal Semiconductors

NASA Astrophysics Data System (ADS)

McCulloch, Iain; Coelle, Michael; Genevicius, Kristijonas; Hamilton, Rick; Heckmeier, Michael; Heeney, Martin; Kreouzis, Theo; Shkunov, Maxim; Zhang, Weimin

2008-01-01

Fabrication of display products by low cost printing technologies such as ink jet, gravure offset lithography and flexography requires solution processable semiconductors for the backplane electronics. The products will typically be of lower performance than polysilicon transistors, but comparable to amorphous silicon. A range of prototypes are under development, including rollable electrophoretic displays, active matrix liquid crystal displays (AMLCD's), and flexible organic light-emitting diode (OLED) displays. Organic semiconductors that offer both electrical performance and stability with respect to storage and operation under ambient conditions are required. This work describes the initial evaluation of reactive mesogen semiconductors, which can polymerise within mesophase temperatures, “freezing in” the order in crosslinked domains. These crosslinked domains offer mechanical stability and are inert to solvent exposure in further processing steps. Reactive mesogens containing conjugated aromatic cores, designed to facilitate charge transport and provide good oxidative stability, were prepared and their liquid crystalline properties evaluated. Both time-of-flight and field effect transistor devices were prepared and their electrical characterisation reported.

Lead Halide Perovskites as Charge Generation Layers for Electron Mobility Measurement in Organic Semiconductors.

PubMed

Love, John A; Feuerstein, Markus; Wolff, Christian M; Facchetti, Antonio; Neher, Dieter

2017-12-06

Hybrid lead halide perovskites are introduced as charge generation layers (CGLs) for the accurate determination of electron mobilities in thin organic semiconductors. Such hybrid perovskites have become a widely studied photovoltaic material in their own right, for their high efficiencies, ease of processing from solution, strong absorption, and efficient photogeneration of charge. Time-of-flight (ToF) measurements on bilayer samples consisting of the perovskite CGL and an organic semiconductor layer of different thickness are shown to be determined by the carrier motion through the organic material, consistent with the much higher charge carrier mobility in the perovskite. Together with the efficient photon-to-electron conversion in the perovskite, this high mobility imbalance enables electron-only mobility measurement on relatively thin application-relevant organic films, which would not be possible with traditional ToF measurements. This architecture enables electron-selective mobility measurements in single components as well as bulk-heterojunction films as demonstrated in the prototypical polymer/fullerene blends. To further demonstrate the potential of this approach, electron mobilities were measured as a function of electric field and temperature in an only 127 nm thick layer of a prototypical electron-transporting perylene diimide-based polymer, and found to be consistent with an exponential trap distribution of ca. 60 meV. Our study furthermore highlights the importance of high mobility charge transporting layers when designing perovskite solar cells.

Basic Performance Test of a Prototype PET Scanner Using CdTe Semiconductor Detectors

NASA Astrophysics Data System (ADS)

Ueno, Y.; Morimoto, Y.; Tsuchiya, K.; Yanagita, N.; Kojima, S.; Ishitsu, T.; Kitaguchi, H.; Kubo, N.; Zhao, S.; Tamaki, N.; Amemiya, K.

2009-02-01

A prototype positron emission tomography (PET) scanner using CdTe semiconductor detectors was developed, and its initial evaluation was conducted. The scanner was configured to form a single detector ring with six separated detector units, each having 96 detectors arranged in three detector layers. The field of view (FOV) size was 82 mm in diameter. Basic physical performance indicators of the scanner were measured through phantom studies and confirmed by rat imaging. The system-averaged energy resolution and timing resolution were 5.4% and 6.0 ns (each in FWHM) respectively. Spatial resolution measured at FOV center was 2.6 mm FWHM. Scatter fraction was measured and calculated in a National Electrical Manufacturers Association (NEMA)-fashioned manner using a 3-mm diameter hot capillary in a water-filled 80-mm diameter acrylic cylinder. The calculated result was 3.6%. Effect of depth of interaction (DOI) measurement was demonstrated by comparing hot-rod phantom images reconstructed with and without DOI information. Finally, images of a rat myocardium and an implanted tumor were visually assessed, and the imaging performance was confirmed.

Ultra-wideband microwave photonic filter with a high Q-factor using a semiconductor optical amplifier.

PubMed

Chen, Han

2017-04-01

An ultra-wideband microwave photonic filter (MPF) with a high quality (Q)-factor based on the birefringence effects in a semiconductor optical amplifier (SOA) is presented, and the theoretical fundamentals of the design are explained. The proposed MPF along orthogonal polarization in an active loop operates at up to a Ku-band and provides a tunable free spectral range from 15.44 to 19.44 GHz by controlling the SOA injection current. A prototype of the equivalent second-order infinite impulse response filter with a Q-factor over 6300 and a rejection ration exceeding 41 dB is experimentally demonstrated.

Strain Imaging of Nanoscale Semiconductor Heterostructures with X-Ray Bragg Projection Ptychography

NASA Astrophysics Data System (ADS)

Holt, Martin V.; Hruszkewycz, Stephan O.; Murray, Conal E.; Holt, Judson R.; Paskiewicz, Deborah M.; Fuoss, Paul H.

2014-04-01

We report the imaging of nanoscale distributions of lattice strain and rotation in complementary components of lithographically engineered epitaxial thin film semiconductor heterostructures using synchrotron x-ray Bragg projection ptychography (BPP). We introduce a new analysis method that enables lattice rotation and out-of-plane strain to be determined independently from a single BPP phase reconstruction, and we apply it to two laterally adjacent, multiaxially stressed materials in a prototype channel device. These results quantitatively agree with mechanical modeling and demonstrate the ability of BPP to map out-of-plane lattice dilatation, a parameter critical to the performance of electronic materials.

Semiconductor laser insert with uniform illumination for use in photodynamic therapy

NASA Astrophysics Data System (ADS)

Charamisinau, Ivan; Happawana, Gemunu; Evans, Gary; Rosen, Arye; Hsi, Richard A.; Bour, David

2005-08-01

A low-cost semiconductor red laser light delivery system for esophagus cancer treatment is presented. The system is small enough for insertion into the patient's body. Scattering elements with nanoscale particles are used to achieve uniform illumination. The scattering element optimization calculations, with Mie theory, provide scattering and absorption efficiency factors for scattering particles composed of various materials. The possibility of using randomly deformed spheres and composite particles instead of perfect spheres is analyzed using an extension to Mie theory. The measured radiation pattern from a prototype light delivery system fabricated using these design criteria shows reasonable agreement with the theoretically predicted pattern.

Changing profile of excimer laser coronary angioplasty: refinements in catheters

NASA Astrophysics Data System (ADS)

Bittl, John A.

1994-07-01

During more than five years of investigation with excimer laser angioplasty, several changes have been made in patient selection and laser catheters. It is unclear, however, whether these changes have improved the outcome of excimer laser angioplasty. A total of 2041 patients underwent treatment with excimer laser coronary angioplasty for 2324 lesions with clinical success in 89%, ischemic complications in 7.5%, and vessel perforation in 2.1%. When the entire 5-year period of investigation was divided into four discrete phases, as defined by the successive release of improved laser catheters (prototype, flexible, extremely flexible, and eccentric), clinical success was seen to improve from 86% to 95% (p<0.001) despite the increased incidence of advanced age (pequals0.01) and unstable angina (p<0.001). Multivariable analysis identified improved laser catheters, saphenous vein graft lesions, and unclarified stenoses as predictors of favorable outcome. Operator experience was associated with decreased complications. Reduced catheter size relative to vessel size was associated with decreased risk of vessel perforation. Thus, refinements in patient selection and in laser technique have been associated with enhanced safety and efficacy of excimer laser angioplasty.

Bioregenerative system components for microgravity

NASA Technical Reports Server (NTRS)

Nevill, Gale E., Jr.; Hessel, Michael I., Jr.

1992-01-01

The goal of the class was to design, fabricate, and test prototype designs that were independent, yet applicable to a Closed Loop Life Support System. The three prototypes chosen were in the areas of agar plant growth, regnerative filtration, and microgravity food preparation. The plant growth group designed a prototype agar medium growth system that incorporates nutrient solution replenishment and post-harvest refurbishment. In addition, the unit emphasizes material containment and minimization of open interfaces. The second project was a filter used in microgravity that has the capability to clean itself. The filters are perforated plates which slide through a duct and are cleaned outside of the flow with a vacuum system. The air in the duct is prevented from flowing outside of the duct by a network of sliding seals. The food preparation group developed a device which dispenses and mixes ingredients and then cooks the mixture in microgravity. The dry ingredients are dispensed from a canister by a ratchet-operated piston. The wet ingredients are dispensed from plastic bags through tubing attached to a syringe. Once inside the mixing chamber, the ingredients are mixed using a collapsible whisk and then pushed into the cooking device.

Photo-induced transformation process at gold clusters-semiconductor interface: Implications for the complexity of gold clusters-based photocatalysis

PubMed Central

Liu, Siqi; Xu, Yi-Jun

2016-01-01

The recent thrust in utilizing atomically precise organic ligands protected gold clusters (Au clusters) as photosensitizer coupled with semiconductors for nano-catalysts has led to the claims of improved efficiency in photocatalysis. Nonetheless, the influence of photo-stability of organic ligands protected-Au clusters at the Au/semiconductor interface on the photocatalytic properties remains rather elusive. Taking Au clusters–TiO2 composites as a prototype, we for the first time demonstrate the photo-induced transformation of small molecular-like Au clusters to larger metallic Au nanoparticles under different illumination conditions, which leads to the diverse photocatalytic reaction mechanism. This transformation process undergoes a diffusion/aggregation mechanism accompanied with the onslaught of Au clusters by active oxygen species and holes resulting from photo-excited TiO2 and Au clusters. However, such Au clusters aggregation can be efficiently inhibited by tuning reaction conditions. This work would trigger rational structural design and fine condition control of organic ligands protected-metal clusters-semiconductor composites for diverse photocatalytic applications with long-term photo-stability. PMID:26947754

Photo-induced transformation process at gold clusters-semiconductor interface: Implications for the complexity of gold clusters-based photocatalysis

NASA Astrophysics Data System (ADS)

Liu, Siqi; Xu, Yi-Jun

2016-03-01

The recent thrust in utilizing atomically precise organic ligands protected gold clusters (Au clusters) as photosensitizer coupled with semiconductors for nano-catalysts has led to the claims of improved efficiency in photocatalysis. Nonetheless, the influence of photo-stability of organic ligands protected-Au clusters at the Au/semiconductor interface on the photocatalytic properties remains rather elusive. Taking Au clusters-TiO2 composites as a prototype, we for the first time demonstrate the photo-induced transformation of small molecular-like Au clusters to larger metallic Au nanoparticles under different illumination conditions, which leads to the diverse photocatalytic reaction mechanism. This transformation process undergoes a diffusion/aggregation mechanism accompanied with the onslaught of Au clusters by active oxygen species and holes resulting from photo-excited TiO2 and Au clusters. However, such Au clusters aggregation can be efficiently inhibited by tuning reaction conditions. This work would trigger rational structural design and fine condition control of organic ligands protected-metal clusters-semiconductor composites for diverse photocatalytic applications with long-term photo-stability.

Power components for the Space Station 20-kHz power distribution system

NASA Technical Reports Server (NTRS)

Renz, David D.

1988-01-01

Since 1984, NASA Lewis Research Center was developing high power, high frequency space power components as part of The Space Station Advanced Development program. The purpose of the Advanced Development program was to accelerate existing component programs to ensure their availability for use on the Space Station. These components include a rotary power transfer device, remote power controllers, remote bus isolators, high power semiconductor, a high power semiconductor package, high frequency-high power cable, high frequency-high power connectors, and high frequency-high power transformers. All the components were developed to the prototype level and will be installed in the Lewis Research Center Space Station power system test bed.

Development of silicon carbide semiconductor devices for high temperature applications

NASA Technical Reports Server (NTRS)

Matus, Lawrence G.; Powell, J. Anthony; Petit, Jeremy B.

1991-01-01

The semiconducting properties of electronic grade silicon carbide crystals, such as wide energy bandgap, make it particularly attractive for high temperature applications. Applications for high temperature electronic devices include instrumentation for engines under development, engine control and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Discrete prototype SiC devices were fabricated and tested at elevated temperatures. Grown p-n junction diodes demonstrated very good rectification characteristics at 870 K. A depletion-mode metal-oxide-semiconductor field-effect transistor was also successfully fabricated and tested at 770 K. While optimization of SiC fabrication processes remain, it is believed that SiC is an enabling high temperature electronic technology.

Power components for the space station 20-kHz power distribution system

NASA Technical Reports Server (NTRS)

Renz, David D.

1988-01-01

Since 1984, NASA Lewis Research Center was developing high power, high frequency space power components as part of The Space Station Advanced Development program. The purpose of The Advanced Development program was to accelerate existing component programs to ensure their availability for use on the Space Station. These components include a rotary power transfer device, remote power controllers, remote bus isolators, high power semiconductor, a high power semiconductor package, high frequency-high power cable, high frequency-high power connectors, and high frequency-high power transformers. All the components were developed to the prototype level and will be installed in the Lewis Research Center Space Station power system test bed.

Frontiers of controlling energy levels at interfaces

NASA Astrophysics Data System (ADS)

Koch, Norbert

The alignment of electron energy levels at interfaces between semiconductors, dielectrics, and electrodes determines the function and efficiency of all electronic and optoelectronic devices. Reliable guidelines for predicting the level alignment for a given material combination and methods to adjust the intrinsic energy landscape are needed to enable efficient engineering approaches. These are sufficiently understood for established electronic materials, e.g., Si, but for the increasing number of emerging materials, e.g., organic and 2D semiconductors, perovskites, this is work in progress. The intrinsic level alignment and the underlying mechanisms at interfaces between organic and inorganic semiconductors are discussed first. Next, methods to alter the level alignment are introduced, which all base on proper charge density rearrangement at a heterojunction. As interface modification agents we use molecular electron acceptors and donors, as well as molecular photochromic switches that add a dynamic aspect and allow device multifunctionality. For 2D semiconductors surface transfer doping with molecular acceptors/donors transpires as viable method to locally tune the Fermi-level position in the energy gap. The fundamental electronic properties of a prototypical 1D interface between intrinsic and p-doped 2D semiconductor regions are derived from local (scanning probe) and area-averaged (photoemission) spectroscopy experiments. Future research opportunities for attaining unsurpassed interface control through charge density management are discussed.

Image-guided modified deep anterior lamellar keratoplasty (DALK) corneal transplant using intraoperative optical coherence tomography

NASA Astrophysics Data System (ADS)

Tao, Yuankai K.; LaBarbera, Michael; Ehlers, Justis P.; Srivastava, Sunil K.; Dupps, William J.

2015-03-01

Deep anterior lamellar keratoplasty (DALK) is an alternative to full-thickness corneal transplant and has advantages including the absence of allograft rejection; shortened duration of topical corticosteroid treatment and reduced associated risk of glaucoma, cataract, or infection; and enables use of grafts with poor endothelial quality. DALK begins by performing a trephination of approximately 80% stromal thickness, as measured by pachymetry. After removal of the anterior stoma, a needle is inserted into the residual stroma to inject air or viscoelastic to dissect Descemet's membrane. These procedures are inherently difficult and intraoperative rates of Descemet's membrane perforation between 4-39% have been reported. Optical coherence tomography (OCT) provides high-resolution images of tissue microstructures in the cornea, including Descemet's membrane, and allows quantitation of corneal layer thicknesses. Here, we use crosssectional intraoperative OCT (iOCT) measurements of corneal thickness during surgery and a novel micrometeradjustable biopsy punch to precision-cut the stroma down to Descemet's membrane. Our prototype cutting tool allows us to establish a dissection plane at the corneal endothelium interface, mitigates variability in cut-depths as a result of tremor, reduces procedure complexity, and reduces complication rates. iOCT-guided modified DALK procedures were performed on 47 cadaveric porcine eyes by non-experts and achieved a perforation rate of ~5% with a mean corneal dissection time <18 minutes. The procedure was also successful performed on a human donor eye without perforation. Our data shows the potential for iOCT-guided precision anterior segment surgery without variability as a result of tremor and improvements to standard clinical care.

Standard Spacecraft Interfaces and IP Network Architectures: Prototyping Activities at the GSFC

NASA Technical Reports Server (NTRS)

Schnurr, Richard; Marquart, Jane; Lin, Michael

2003-01-01

Advancements in fright semiconductor technology have opened the door for IP-based networking in spacecraft architectures. The GSFC believes the same signlJicant cost savings gained using MIL-STD-1553/1773 as a standard low rate interface for spacecraft busses cun be realized for highspeed network interfaces. To that end, GSFC is developing hardware and software to support a seamless, space mission IP network based on Ethernet and MIL-STD-1553. The Ethernet network shall connect all fright computers and communications systems using interface standards defined by the CCSDS Standard Onboard InterFace (SOIF) Panel. This paper shall discuss the prototyping effort underway at GSFC and expected results.

Sustained hole inversion layer in a wide-bandgap metal-oxide semiconductor with enhanced tunnel current

NASA Astrophysics Data System (ADS)

Shoute, Gem; Afshar, Amir; Muneshwar, Triratna; Cadien, Kenneth; Barlage, Douglas

2016-02-01

Wide-bandgap, metal-oxide thin-film transistors have been limited to low-power, n-type electronic applications because of the unipolar nature of these devices. Variations from the n-type field-effect transistor architecture have not been widely investigated as a result of the lack of available p-type wide-bandgap inorganic semiconductors. Here, we present a wide-bandgap metal-oxide n-type semiconductor that is able to sustain a strong p-type inversion layer using a high-dielectric-constant barrier dielectric when sourced with a heterogeneous p-type material. A demonstration of the utility of the inversion layer was also investigated and utilized as the controlling element in a unique tunnelling junction transistor. The resulting electrical performance of this prototype device exhibited among the highest reported current, power and transconductance densities. Further utilization of the p-type inversion layer is critical to unlocking the previously unexplored capability of metal-oxide thin-film transistors, such applications with next-generation display switches, sensors, radio frequency circuits and power converters.

Compact vacuum tubes with GaAs(Cs,O) photocathodes for studying spin-dependent phenomena

NASA Astrophysics Data System (ADS)

Alperovich, V. L.; Orlov, D. A.; Grishaev, V. G.; Kosolobov, S. N.; Jaroshevich, A. S.; Scheibler, H. E.; Terekhov, A. S.

2009-08-01

Compact proximity focused vacuum tubes with GaAs(Cs,O) photocathodes are used for experimental studying spindependent phenomena. Firstly, spin-dependent emission of optically oriented electrons from p-GaAs(Cs,O) into vacuum in a magnetic field normal to the surface was observed in a nonmagnetic vacuum diode. This phenomenon is explained by the jump in the electron g-factor at the semiconductor-vacuum interface. Due to this jump, the effective electron affinity on the semiconductor surface depends on the mutual direction of optically oriented electron spins and the magnetic field, resulting in the spin-dependent photoemission. It is demonstrated that the observed effect can be used for the determination of spin diffusion length in semiconductors. Secondly, we developed a prototype of a new spin filter, which consists of a vacuum tube with GaAs(Cs,O) photocathode and a nickel-covered venetian blind dynode. Preliminary results on spin-dependent reflection of electrons from the oxidized polycrystal nickel layer are presented.

Optical Absorption in Degenerately Doped Semiconductors: Mott Transition or Mahan Excitons?

NASA Astrophysics Data System (ADS)

Schleife, André; Rödl, Claudia; Fuchs, Frank; Hannewald, Karsten; Bechstedt, Friedhelm

2011-12-01

Electron doping turns semiconductors conductive even when they have wide fundamental band gaps. The degenerate electron gas in the lowest conduction-band states, e.g., of a transparent conducting oxide, drastically modifies the Coulomb interaction between the electrons and, hence, the optical properties close to the absorption edge. We describe these effects by developing an ab initio technique which captures also the Pauli blocking and the Fermi-edge singularity at the optical-absorption onset, that occur in addition to quasiparticle and excitonic effects. We answer the question whether free carriers induce an excitonic Mott transition or trigger the evolution of Wannier-Mott excitons into Mahan excitons. The prototypical n-type zinc oxide is studied as an example.

A modular optically powered floating high voltage generator.

PubMed

Antonini, P; Borsato, E; Carugno, G; Pegoraro, M; Zotto, P

2013-02-01

The feasibility of fully floating high voltage (HV) generation was demonstrated producing a prototype of a modular HV system. The primary power source is provided by a high efficiency semiconductor power cell illuminated by a laser system ensuring the floating nature of each module. The HV is then generated by dc-dc conversion and a HV multiplier. The possibility of series connection among modules was verified.

Development of a self-healing soft pneumatic actuator: a first concept.

PubMed

Terryn, Seppe; Mathijssen, Glenn; Brancart, Joost; Lefeber, Dirk; Assche, Guy Van; Vanderborght, Bram

2015-07-07

Inspired by the intrinsic softness and the corresponding embodied intelligence principles, soft pneumatic actuators (SPA) have been developed, which ensure safe interaction in unstructured, unknown environments. Due to their intrinsic softness, these actuators have the ability to resist large mechanical impacts. However, the soft materials used in these structures are in general susceptible to damage caused by sharp objects found in the unstructured environments. This paper proposes to integrate a self-healing (SH-) mechanism in SPAs, such that cuts, tears and perforations in the actuator can be self-healed. Diels-Alder (DA-) polymers, covalent polymer network systems based on the thermoreversible DA-reaction, were selected and their mechanical, as well as SH-properties, are described. To evaluate the feasibility of developing an SPA constructed out of SH-material, a single cell prototype, a SH-soft pneumatic cell (SH-SPC), was constructed entirely out of DA-polymers. Exploiting the SH-property of the DA-polymers, a completely new shaping process is presented in this paper, referred to as 'shaping through folding and self-healing'. 3D polygon structures, like the cubic SH-SPC, can be constructed by folding SH-polymer sheet. The sides of the structures can be sealed and made airtight using a SH-procedure at relatively low temperatures (<90 °C). Both the (thermo) mechanical and SH-properties of the SH-SPC prototype were experimentally validated and showed excellent performances. Macroscopic incisions in the prototype were completely healed using a SH-procedure (<70 °C). Starting from this single-cell prototype, it is straight-forward to develop a multi-cell prototype, the first SPA ever built completely out of SH-polymers.

Preliminary results for mask metrology using spatial heterodyne interferometry

NASA Astrophysics Data System (ADS)

Bingham, Philip R.; Tobin, Kenneth; Bennett, Marylyn H.; Marmillion, Pat

2003-12-01

Spatial heterodyne interferometry (SHI) is an imaging technique that captures both the phase and amplitude of a complex wavefront in a single high-speed image. This technology was developed at the Oak Ridge National Laboratory (ORNL) and is currently being implemented for semiconductor wafer inspection by nLine Corporation. As with any system that measures phase, metrology and inspection of surface structures is possible by capturing a wavefront reflected from the surface. The interpretation of surface structure heights for metrology applications can become very difficult with the many layers of various materials used on semiconductor wafers, so inspection (defect detection) has been the primary focus for semiconductor wafers. However, masks used for photolithography typically only contain a couple well-defined materials opening the doors to high-speed mask metrology in 3 dimensions in addition to inspection. Phase shift masks often contain structures etched out of the transparent substrate material for phase shifting. While these structures are difficult to inspect using only intensity, the phase and amplitude images captured with SHI can produce very good resolution of these structures. The phase images also provide depth information that is crucial for these phase shift regions. Preliminary testing has been performed to determine the feasibility of SHI for high-speed non-contact mask metrology using a prototype SHI system with 532 nm wavelength illumination named the Visible Alpha Tool (VAT). These results show that prototype SHI system is capable of performing critical dimension measurements on 400nm lines with a repeatability of 1.4nm and line height measurements with a repeatability of 0.26nm. Additionally initial imaging of an alternating aperture phase shift mask has shown the ability of SHI to discriminate between typical phase shift heights.

Development of Prototype Micro-Lidar using Narrow Linewidth Semiconductor Lasers for Mars Boundary Layer Wind and Dust Opacity Profiles

NASA Technical Reports Server (NTRS)

Menzies, Robert T.; Cardell, Greg; Chiao, Meng; Esproles, Carlos; Forouhar, Siamak; Hemmati, Hamid; Tratt, David

1999-01-01

We have developed a compact Doppler lidar concept which utilizes recent developments in semiconductor diode laser technology in order to be considered suitable for wind and dust opacity profiling in the Mars lower atmosphere from a surface location. The current understanding of the Mars global climate and meteorology is very limited, with only sparse, near-surface data available from the Viking and Mars Pathfinder landers, supplemented by long-range remote sensing of the Martian atmosphere. The in situ measurements from a lander-based Doppler lidar would provide a unique dataset particularly for the boundary layer. The coupling of the radiative properties of the lower atmosphere with the dynamics involves the radiative absorption and scattering effects of the wind-driven dust. Variability in solar irradiance, on diurnal and seasonal time scales, drives vertical mixing and PBL (planetary boundary layer) thickness. The lidar data will also contribute to an understanding of the impact of wind-driven dust on lander and rover operations and lifetime through an improvement in our understanding of Mars climatology. In this paper we discuss the Mars lidar concept, and the development of a laboratory prototype for performance studies, using, local boundary layer and topographic target measurements.

Soft gamma-ray detector for the ASTRO-H Mission

NASA Astrophysics Data System (ADS)

Watanabe, Shin; Tajima, Hiroyasu; Fukazawa, Yasushi; Blandford, Roger; Enoto, Teruaki; Kataoka, Jun; Kawaharada, Madoka; Kokubun, Motohide; Laurent, Philippe; Lebrun, François; Limousin, Olivier; Madejski, Greg; Makishima, Kazuo; Mizuno, Tsunefumi; Nakamori, Takeshi; Nakazawa, Kazuhiro; Mori, Kunishiro; Odaka, Hirokazu; Ohno, Masanori; Ohta, Masayuki; Sato, Goro; Sato, Rie; Takeda, Shin'ichiro; Takahashi, Hiromitsu; Takahashi, Tadayuki; Tanaka, Takaaki; Tashiro, Makoto; Terada, Yukikatsu; Uchiyama, Hideki; Uchiyama, Yasunobu; Yamada, Shinya; Yatsu, Yoichi; Yonetoku, Daisuke; Yuasa, Takayuki

2012-09-01

ASTRO-H is the next generation JAXA X-ray satellite, intended to carry instruments with broad energy coverage and exquisite energy resolution. The Soft Gamma-ray Detector (SGD) is one of ASTRO-H instruments and will feature wide energy band (60-600 keV) at a background level 10 times better than the current instruments on orbit. The SGD is complimentary to ASTRO-H’s Hard X-ray Imager covering the energy range of 5-80 keV. The SGD achieves low background by combining a Compton camera scheme with a narrow field-of-view active shield where Compton kinematics is utilized to reject backgrounds. The Compton camera in the SGD is realized as a hybrid semiconductor detector system which consists of silicon and CdTe (cadmium telluride) sensors. Good energy resolution is afforded by semiconductor sensors, and it results in good background rejection capability due to better constraints on Compton kinematics. Utilization of Compton kinematics also makes the SGD sensitive to the gamma-ray polarization, opening up a new window to study properties of gamma-ray emission processes. In this paper, we will present the detailed design of the SGD and the results of the final prototype developments and evaluations. Moreover, we will also present expected performance based on the measurements with prototypes.

Plasmon satellites in valence-band photoemission spectroscopy. Ab initio study of the photon-energy dependence in semiconductors

NASA Astrophysics Data System (ADS)

Guzzo, M.; Kas, J. J.; Sottile, F.; Silly, M. G.; Sirotti, F.; Rehr, J. J.; Reining, L.

2012-09-01

We present experimental data and theoretical results for valence-band satellites in semiconductors, using the prototypical example of bulk silicon. In a previous publication we introduced a new approach that allows us to describe satellites in valence photoemission spectroscopy, in good agreement with experiment. Here we give more details; we show how the the spectra change with photon energy, and how the theory explains this behaviour. We also describe how we include several effects which are important to obtain a correct comparison between theory and experiment, such as secondary electrons and photon cross sections. In particular the inclusion of extrinsic losses and their dependence on the photon energy are key to the description of the energy dependence of spectra.

The Operator Guide: An Ambient Persuasive Interface in the Factory

NASA Astrophysics Data System (ADS)

Meschtscherjakov, Alexander; Reitberger, Wolfgang; Pöhr, Florian; Tscheligi, Manfred

In this paper we introduce the context of a semiconductor factory as a promising area for the application of innovative interaction approaches. In order to increase efficiency ambient persuasive interfaces, which influence the operators' behaviour to perform in an optimized way, could constitute a potential strategy. We present insights gained from qualitative studies conducted in a specific semiconductor factory and provide a description of typical work processes and already deployed interfaces in this context. These findings informed the design of a prototype of an ambient persuasive interface within this realm - the "Operator Guide". Its overall aim is to improve work efficiency, while still maintaining a minimal error rate. We provide a detailed description of the Operator Guide along with an outlook of the next steps within a user-centered design approach.

Quantitative analysis of valence photoemission spectra and quasiparticle excitations at chromophore-semiconductor interfaces.

PubMed

Patrick, Christopher E; Giustino, Feliciano

2012-09-14

Investigating quasiparticle excitations of molecules on surfaces through photoemission spectroscopy forms a major part of nanotechnology research. Resolving spectral features at these interfaces requires a comprehensive theory of electron removal and addition processes in molecules and solids which captures the complex interplay of image charges, thermal effects, and configurational disorder. Here, we develop such a theory and calculate the quasiparticle energy-level alignment and the valence photoemission spectrum for the prototype biomimetic solar cell interface between anatase TiO(2) and the N3 chromophore. By directly matching our calculated photoemission spectrum to experimental data, we clarify the atomistic origin of the chromophore peak at low binding energy. This case study sets a new standard in the interpretation of photoemission spectroscopy at complex chromophore-semiconductor interfaces.

Spectrum of perforation peritonitis in delhi: 77 cases experience.

PubMed

Yadav, Dinesh; Garg, Puneet K

2013-04-01

Perforation peritonitis is the most common surgical emergency encountered by surgeons all over the world as well in India. The spectrum of etiology of perforation peritonitis in tropical countries continues to differ from its western counterpart. This study was conducted at Hindu Rao Hospital, Municipal Corporation of Delhi, New Delhi, India, designed to highlight the spectrum of perforation peritonitis in the eastern countries and to improve its outcome. This prospective study included 77 consecutive patients of perforation peritonitis studied in terms of clinical presentations, causes, site of perforation, surgical treatment, postoperative complications, and mortality at Hindu Rao Hospital, Delhi, from March 1, 2011 to December 1, 2011, over a period of 8 months. All patients were resuscitated and underwent emergency exploratory laparotomy. On laparotomy cause of perforation peritonitis was found and controlled. The most common cause of perforation peritonitis noticed in our series was perforated duodenal ulcer (26.4 %) and ileal typhoid perforation (26.4 %), each followed by small bowel tuberculosis (10.3 %) and stomach perforation (9.2 %), perforation due to acute appendicitis (5 %). The highest number of perforations was seen in ileum (39.1 %), duodenum (26.4 %), stomach (11.5 %), appendix (3.5 %), jejunum (4.6 %), and colon (3.5 %). Overall mortality was 13 %. The spectrum of perforation peritonitis in India continuously differs from western countries. The highest number of perforations was noticed in the upper part of the gastrointestinal tract as compared to the western countries where the perforations seen mostly in the distal part. The most common cause of perforation peritonitis was perforated duodenal ulcer and small bowel typhoid perforation followed by typhoid perforation. Large bowel perforations and malignant perforations were least common in our setup.

Design of an Inductive Adder for the FCC injection kicker pulse generator

NASA Astrophysics Data System (ADS)

Woog, D.; Barnes, M. J.; Ducimetière, L.; Holma, J.; Kramer, T.

2017-07-01

The injection system for a 100 TeV centre-of-mass collider is an important part of the Future Circular Collider (FCC) study. Due to issues with conventional kicker systems, such as self-triggering and long term availability of thyratrons and limitations of HV-cables, innovative design changes are planned for the FCC injection kicker pulse generator. An inductive adder (IA) based on semiconductor (SC) switches is a promising technology for kicker systems. Its modular design, and the possibility of an active ripple suppression are significant advantages. Since the IA is a complex device, with multiple components whose characteristics are important, a detailed design study and construction of a prototype is necessary. This paper summarizes the system requirements and constraints, and describes the main components and design challenges of the prototype IA. It outlines the results from simulations and measurements on different magnetic core materials as well as on SC switches. The paper concludes on the design choices and progress for the prototype to be built at CERN.

Spectrum of perforation peritonitis in Pakistan: 300 cases Eastern experience.

PubMed

Afridi, Shahida Parveen; Malik, Faiza; Ur-Rahman, Shafiq; Shamim, Shahid; Samo, Khursheed A

2008-11-08

Perforation peritonitis is the most common surgical emergency encountered by the surgeons all over the world as well in Pakistan. The spectrum of etiology of perforation peritonitis in tropical countries continues to differ from its western counter part. This study was conducted at Dow University of health sciences and Civil Hospital Karachi (DUHS & CHK) Pakistan, designed to highlight the spectrum of perforation peritonitis in the East and to improve its outcome. A prospective study includes three hundred consecutive patients of perforation peritonitis studied in terms of clinical presentations, Causes, site of perforation, surgical treatment, post operative complications and mortality, at (DUHS&CHK) Pakistan, from 1st September 2005 - 1st March 2008, over a period of two and half years. All patients were resuscitated underwent emergency exploratory laparotomy. On laparotomy cause of perforation peritonitis was found and controlled. The most common cause of perforation peritonitis noticed in our series was acid peptic disease 45%, perforated duodenal ulcer (43.6%) and gastric ulcer 1.3%. followed by small bowel tuberculosis (21%) and typhoid (17%). large bowel perforation due to tuberculosis 5%, malignancy 2.6% and volvulus 0.3%. Perforation due to acute appendicitis (5%). Highest number of perforations has seen in the duodenum 43.6%, ileum37.6%, and colon 8%, appendix 5%, jejunum 3.3%, and stomach 2.3%. Overall mortality was (10.6%). The spectrum of perforation peritonitis in Pakistan continuously differs from western country. Highest number of perforations noticed in the upper part of the gastrointestinal tract as compared to the western countries where the perforations seen mostly in the distal part. Most common cause of perforation peritonitis is perforated duodenal ulcer, followed by small bowel tuberculosis and typhoid perforation. Majority of the large bowel perforations are also tubercular. Malignant perforations are least common in our setup.

Prototyping and implementing flight qualifiable semicustom CMOS P-well bulk integrated circuits in the JPL environment

NASA Technical Reports Server (NTRS)

Olson, E. M.

1986-01-01

Presently, there are many difficulties associated with implementing application specific custom or semi-custom (standard cell based) integrated circuits (ICs) into JPL flight projects. One of the primary difficulties is developing prototype semi-custom integrated circuits for use and evaluation in engineering prototype flight hardware. The prototype semi-custom ICs must be extremely cost-effective and yet still representative of flight qualifiable versions of the design. A second difficulty is encountered in the transport of the design from engineering prototype quality to flight quality. Normally, flight quality integrated circuits have stringent quality standards, must be radiation resistant and should consume minimal power. It is often not necessary or cost effective, however, to impose such stringent quality standards on engineering models developed for systems analysis in controlled lab environments. This article presents work originally initiated for ground based applications that also addresses these two problems. Furthermore, this article suggests a method that has been shown successful in prototyping flight quality semi-custom ICs through the Metal Oxide Semiconductor Implementation Service (MOSIS) program run by the University of Southern California's Information Sciences Institute. The method has been used successfully to design and fabricate through the MOSIS three different semi-custom prototype CMOS p-well chips. The three designs make use of the work presented and were designed consistent with design techniques and structures that are flight qualifiable, allowing one hour transfer of the design from engineering model status to flight qualifiable foundry-ready status through methods outlined in this article.

Sustained hole inversion layer in a wide-bandgap metal-oxide semiconductor with enhanced tunnel current

PubMed Central

Shoute, Gem; Afshar, Amir; Muneshwar, Triratna; Cadien, Kenneth; Barlage, Douglas

2016-01-01

Wide-bandgap, metal-oxide thin-film transistors have been limited to low-power, n-type electronic applications because of the unipolar nature of these devices. Variations from the n-type field-effect transistor architecture have not been widely investigated as a result of the lack of available p-type wide-bandgap inorganic semiconductors. Here, we present a wide-bandgap metal-oxide n-type semiconductor that is able to sustain a strong p-type inversion layer using a high-dielectric-constant barrier dielectric when sourced with a heterogeneous p-type material. A demonstration of the utility of the inversion layer was also investigated and utilized as the controlling element in a unique tunnelling junction transistor. The resulting electrical performance of this prototype device exhibited among the highest reported current, power and transconductance densities. Further utilization of the p-type inversion layer is critical to unlocking the previously unexplored capability of metal-oxide thin-film transistors, such applications with next-generation display switches, sensors, radio frequency circuits and power converters. PMID:26842997

Endodontic applications of 3D printing.

PubMed

Anderson, J; Wealleans, J; Ray, J

2018-02-27

Computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies can leverage cone beam computed tomography data for production of objects used in surgical and nonsurgical endodontics and in educational settings. The aim of this article was to review all current applications of 3D printing in endodontics and to speculate upon future directions for research and clinical use within the specialty. A literature search of PubMed, Ovid and Scopus was conducted using the following terms: stereolithography, 3D printing, computer aided rapid prototyping, surgical guide, guided endodontic surgery, guided endodontic access, additive manufacturing, rapid prototyping, autotransplantation rapid prototyping, CAD, CAM. Inclusion criteria were articles in the English language documenting endodontic applications of 3D printing. Fifty-one articles met inclusion criteria and were utilized. The endodontic literature on 3D printing is generally limited to case reports and pre-clinical studies. Documented solutions to endodontic challenges include: guided access with pulp canal obliteration, applications in autotransplantation, pre-surgical planning and educational modelling and accurate location of osteotomy perforation sites. Acquisition of technical expertise and equipment within endodontic practices present formidable obstacles to widespread deployment within the endodontic specialty. As knowledge advances, endodontic postgraduate programmes should consider implementing 3D printing into their curriculums. Future research directions should include clinical outcomes assessments of treatments employing 3D printed objects. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

A novel hydrogel based piezoresistive pressure sensor platform for chemical sensing

NASA Astrophysics Data System (ADS)

Orthner, Michael P.

New hydrogel-based micropressure sensor arrays for use in the fields of chemical sensing, physiological monitoring, and medical diagnostics are developed and demonstrated. This sensor technology provides reliable, linear, and accurate measurements of hydrogel swelling pressures, a function of ambient chemical concentrations. For the first time, perforations were implemented into the pressure sensors piezoresistive diaphragms, used to simultaneously increase sensor sensitivity and permit diffusion of analytes into the hydrogel cavity. It was shown through analytical and numerical (finite element) methods that pore shape, location, and size can be used to modify the diaphragm mechanics and concentrate stress within the piezoresistors, thus improving electrical output (sensitivity). An optimized pore pattern was chosen based on these numerical calculations. Fabrication was performed using a 14-step semiconductor fabrication process implementing a combination of potassium hydroxide (KOH) and deep reactive ion etching (DRIE) to create perforations. The sensor arrays (2x2) measure approximately 3 x 5 mm2 and used to measure full scale pressures of 50, 25, and 5 kPa, respectively. These specifications were defined by the various swelling pressures of ionic strength, pH and glucose specific hydrogels that were targeted in this work. Initial characterization of the sensor arrays was performed using a custom built bulge testing apparatus that simultaneously measured deflection (optical profilometry), pressure, and electrical output. The new perforated diaphragm sensors were found to be fully functional with sensitivities ranging from 23 to 252 muV/V-kPa with full scale output (FSO) ranging from 5 to 80 mV. To demonstrate proof of concept, hydrogels sensitive to changes in ionic strength were synthesized using hydroxypropyl-methacrylate (HPMA), N,N-dimethylaminoethyl-methacrylate (DMA) and a tetra-ethyleneglycol-dimethacrylate (TEGDMA) crosslinker. This hydrogel quickly and reversibly swells when placed environments of physiological buffer solutions (PBS) with ionic strengths ranging from 0.025 to 0.15 M. Chemical testing showed sensors with perforated diaphragms have higher sensitivity than those with solid diaphragms, and sensitivities ranging from 53.3+/-6.5 to 271.47+/-27.53 mV/V-M, depending on diaphragm size. Additionally, recent experiments show sensors utilizing Ultra Violet (UV) polymerized glucose sensitive hydrogels respond reversibly to physiologically relevant glucose concentrations from 0 to 20 mM.

Determination of authenticity of brand perfume using electronic nose prototypes

NASA Astrophysics Data System (ADS)

Gebicki, Jacek; Szulczynski, Bartosz; Kaminski, Marian

2015-12-01

The paper presents the practical application of an electronic nose technique for fast and efficient discrimination between authentic and fake perfume samples. Two self-built electronic nose prototypes equipped with a set of semiconductor sensors were employed for that purpose. Additionally 10 volunteers took part in the sensory analysis. The following perfumes and their fake counterparts were analysed: Dior—Fahrenheit, Eisenberg—J’ose, YSL—La nuit de L’homme, 7 Loewe and Spice Bomb. The investigations were carried out using the headspace of the aqueous solutions. Data analysis utilized multidimensional techniques: principle component analysis (PCA), linear discrimination analysis (LDA), k-nearest neighbour (k-NN). The results obtained confirmed the legitimacy of the electronic nose technique as an alternative to the sensory analysis as far as the determination of authenticity of perfume is concerned.

MEDEA+ project 2T302 MUSCLE: masks through user's supply chain: leadership by excellence

NASA Astrophysics Data System (ADS)

Torsy, Andreas

2008-04-01

The rapid evolution of our information society depends on the continuous developments and innovations of semiconductor products. The cost per chip functionality keeps reducing by a factor of 2 every 18 month. However, this performance and success of the semiconductor industry critically depends on the quality of the lithographic photomasks. The need for the high quality of photomask drives lithography costs sensitively, which is a key factor in the manufacture of microelectronics devices. Therefore, the aim is to reduce production costs while overcoming challenges in terms of feature sizes, complexity and cycle times. Consequently, lithography processes must provide highest possible quality at reasonable prices. This way, the leadership in the lithographic area can be maintained and European chipmakers can stay competitive with manufacturers in the Far East and the USA. Under the umbrella of MEDEA+, a project called MUSCLE (<< Masks through User's Supply Chain: Leadership by Excellence >>) has been started among leading semiconductor companies in Europe: ALTIS Semiconductor (Project Leader), ALCATEL Vacuum, ATMEL, CEA/LETI, Entegris, NXP Semiconductors, TOPPAN Photomasks, AMTC, Carl ZEISS SMS, DMS, Infineon Technologies, VISTEC Semiconductor, NIKON Precision, SCHOTT Lithotec, ASML, PHOTRONICS, IMEC, DCE, DNP Photomask, STMicroelectronics, XYALIS and iCADA. MUSCLE focuses particularly on mask data flow, photomask carrier, photomask defect characterization and photomask data handling. In this paper, we will discuss potential solutions like standardization and automation of the photomask data flow based on SEMI P10, the performance and the impact of the supply chain parameter within the photomask process, the standardization of photomask defect characterization and a discussion of the impact of new Reticle Enhancement Technologies (RET) such as mask process correction and finally a generic model to describe the photomasks key performance indicators for prototype photomasks.

Spin Coherence at the Nanoscale: Polymer Surfaces and Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Epstein, Arthur J.

2013-09-10

Breakthrough results were achieved during the reporting period in the areas of organic spintronics. (A) For the first time the giant magnetic resistance (GMR) was observed in spin valve with an organic spacer. Thus we demonstrated the ability of organic semiconductors to transport spin in GMR devices using rubrene as a prototype for organic semiconductors. (B) We discovered the electrical bistability and spin valve effect in a ferromagnet /organic semiconductor/ ferromagnet heterojunction. The mechanism of switching between conducting phases and its potential applications were suggested. (C) The ability of V(TCNE)x to inject spin into organic semiconductors such as rubrene wasmore » demonstrated for the first time. The mechanisms of spin injection and transport from and into organic magnets as well through organic semiconductors were elucidated. (D) In collaboration with the group of OSU Prof. Johnston-Halperin we reported the successful extraction of spin polarized current from a thin film of the organic-based room temperature ferrimagnetic semiconductor V[TCNE]x and its subsequent injection into a GaAs/AlGaAs light-emitting diode (LED). Thus all basic steps for fabrication of room temperature, light weight, flexible all organic spintronic devices were successfully performed. (E) A new synthesis/processing route for preparation of V(TCNE)x enabling control of interface and film thicknesses at the nanoscale was developed at OSU. Preliminary results show these films are higher quality and what is extremely important they are substantially more air stable than earlier prepared V(TCNE)x. In sum the breakthrough results we achieved in the past two years form the basis of a promising new technology, Multifunctional Flexible Organic-based Spintronics (MFOBS). MFOBS technology enables us fabrication of full function flexible spintronic devices that operate at room temperature.« less

Prediction of weak topological insulators in layered semiconductors.

PubMed

Yan, Binghai; Müchler, Lukas; Felser, Claudia

2012-09-14

We report the discovery of weak topological insulators by ab initio calculations in a honeycomb lattice. We propose a structure with an odd number of layers in the primitive unit cell as a prerequisite for forming weak topological insulators. Here, the single-layered KHgSb is the most suitable candidate for its large bulk energy gap of 0.24 eV. Its side surface hosts metallic surface states, forming two anisotropic Dirac cones. Although the stacking of even-layered structures leads to trivial insulators, the structures can host a quantum spin Hall layer with a large bulk gap, if an additional single layer exists as a stacking fault in the crystal. The reported honeycomb compounds can serve as prototypes to aid in the finding of new weak topological insulators in layered small-gap semiconductors.

Charge-flow structures as polymeric early-warning fire alarm devices. M.S. Thesis; [metal oxide semiconductors

NASA Technical Reports Server (NTRS)

Sechen, C. M.; Senturia, S. D.

1977-01-01

The charge-flow transistor (CFT) and its applications for fire detection and gas sensing were investigated. The utility of various thin film polymers as possible sensing materials was determined. One polymer, PAPA, showed promise as a relative humidity sensor; two others, PFI and PSB, were found to be particularly suitable for fire detection. The behavior of the charge-flow capacitor, which is basically a parallel-plate capacitor with a polymer-filled gap in the metallic tip electrode, was successfully modeled as an RC transmission line. Prototype charge-flow transistors were fabricated and tested. The effective threshold voltage of this metal oxide semiconductor was found to be dependent on whether surface or bulk conduction in the thin film was dominant. Fire tests with a PFI-coated CFT indicate good sensitivity to smouldering fires.

Detection of fast neutrons from shielded nuclear materials using a semiconductor alpha detector.

PubMed

Pöllänen, R; Siiskonen, T

2014-08-01

The response of a semiconductor alpha detector to fast (>1 MeV) neutrons was investigated by using measurements and simulations. A polyethylene converter was placed in front of the detector to register recoil protons generated by elastic collisions between neutrons and hydrogen nuclei of the converter. The developed prototype equipment was tested with shielded radiation sources. The low background of the detector and insensitivity to high-energy gamma rays above 1 MeV are advantages when the detection of neutron-emitting nuclear materials is of importance. In the case of a (252)Cf neutron spectrum, the intrinsic efficiency of fast neutron detection was determined to be 2.5×10(-4), whereas three-fold greater efficiency was obtained for a (241)AmBe neutron spectrum. Copyright © 2014 Elsevier Ltd. All rights reserved.

The accuracy and safety of fluoroscopic-guided percutaneous pedicle screws in the thoracic and lumbosacral spine in the Asian population: A CT scan analysis of 1002 screws.

PubMed

Chiu, Chee Kidd; Chan, Chris Yin Wei; Kwan, Mun Keong

2017-01-01

This study investigates the safety and accuracy of percutaneous pedicle screws placed using fluoroscopic guidance in the thoracolumbosacral spine among Asian patients. Computerized tomography scans of 128 patients who had surgery using fluoroscopic-guided percutaneous pedicle screws were selected. Medial, lateral, superior, and inferior screw perforations were classified into grade 0 (no violation), grade 1 (<2 mm perforation), grade 2 (2-4 mm perforation), and grade 3(>4 mm perforation). Anterior perforations were classified into grade 0 (no violation), grade 1 (<4 mm perforation), grade 2 (4-6 mm perforation), and grade 3(>6 mm perforation). Grade 2 and grade 3 perforation were considered as "critical" perforation. In total, 1002 percutaneous pedicle screws from 128 patients were analyzed. The mean age was 52.7 ± 16.6. There were 70 male patients and 58 female patients. The total perforation rate was 11.3% (113) with 8.4% (84) grade 1, 2.6% (26) grade 2, and 0.3% (3) grade 3 perforations. The overall "critical" perforation rate was 2.9% (29 screws) and no complications were noted. The highest perforation rates were at T4 (21.6%), T2 (19.4%), and T6 (19.2%). The total perforation rate of 11.3% with the total "critical" perforation rate of 2.9% (2.6% grade 2 and 0.3% grade 3 perforations). The highest perforation rates were found over the upper to mid-thoracic region. Fluoroscopic-guided percutaneous pedicle screws insertion among Asians has the safety and accuracy comparable to the current reported percutaneous pedicle screws and open pedicle screws techniques.

F-16XL Ship #1 in flight - used for laminar airflow studies

NASA Technical Reports Server (NTRS)

1992-01-01

One of two F-16XL prototype aircraft, on loan from the Air Force, was used by NASA's Dryden Flight Research Center, Edwards, California, in a program to investigate laminar flow technology and help improve the flow of air over an aircraft's wing at sustained supersonic speeds. A small, perforated titanium wing glove with a turbo compressor was tested on the F-16XL to determine if air suction can remove a small part of the boundary-layer air flowing over the wing and thereby achieve laminar (smooth) flow over a portion of the wing. The flight research program on ship #1 ended in 1996. It was then conducted with NASA's two-seat F-16XL, ship #2 employing a larger glove.

Posterior repair with perforated porcine dermal graft.

PubMed

Taylor, G Bernard; Moore, Robert D; Miklos, John R; Mattox, T Fleming

2008-01-01

To compare postoperative vaginal incision separation and healing in patients undergoing posterior repair with perforated porcine dermal grafts with those that received grafts without perforations. Secondarily, the tensile properties of the perforated and non-perforated grafts were measured and compared. This was a non-randomized retrospective cohort analysis of women with stage II or greater rectoceles who underwent posterior repair with perforated and non-perforated porcine dermal grafts (Pelvicol(TM) CR Bard Covington, GA USA). The incidence of postoperative vaginal incision separation (dehiscence) was compared. A secondary analysis to assess graft tensile strength, suture pull out strength, and flexibility after perforation was performed using standard test method TM 0133 and ASTM bending and resistance protocols. Seventeen percent of patients (21/127) who received grafts without perforations developed vaginal incision dehiscence compared to 7% (5/71) of patients who received perforated grafts (p = 0.078). Four patients with vaginal incision dehiscence with non-perforated grafts required surgical revision to facilitate healing. Neither tensile strength or suture pull out strength were significantly different between perforated and non-perforated grafts (p = 0.81, p = 0.29, respectively). There was no difference in the flexibility of the two grafts (p = 0.20). Perforated porcine dermal grafts retain their tensile properties and are associated with fewer vaginal incision dehiscences.

Metal-oxide-metal point contact junction detectors. [detection mechanism and mechanical stability

NASA Technical Reports Server (NTRS)

Baird, J.; Havemann, R. H.; Fults, R. D.

1973-01-01

The detection mechanism(s) and design of a mechanically stable metal-oxide-metal point contact junction detector are considered. A prototype for a mechanically stable device has been constructed and tested. A technique has been developed which accurately predicts microwave video detector and heterodyne mixer SIM (semiconductor-insulator-metal) diode performance from low dc frequency volt-ampere curves. The difference in contact potential between the two metals and geometrically induced rectification constitute the detection mechanisms.

Experimental and Theoretical Study of the Temperature Performance of Type-II Quantum Well Lasers

DTIC Science & Technology

2007-05-31

performance of type-II Interband Cascade (IC) GaSb-based semiconductor lasers has been developed. The method includes comparing the temperature-concentration... dependence at the laser threshold with steady-state carrier heating characteristics. The number of cascades in prototype type-II IC lasers has been...Monroy, and R.L.Tober, "Wavelength Tuning of Interband Cascade Laser Based on the Stark Effect", in “Future Trends in Microelectronics” ed. by

Prototypical Organic–Oxide Interface: Intramolecular Resolution of Sexiphenyl on In 2O 3 (111)

DOE PAGES

Wagner, Margareta; Hofinger, Jakob; Setvin, Martin; ...

2018-03-28

The performance of an organic semiconductor device is critically determined by the geometric alignment, orientation, and ordering of the organic molecules. Although an organic multilayer eventually adopts the crystal structure of the organic material, the alignment and configuration at the interface with the substrate/electrode material are essential for charge injection into the organic layer. This work focuses on the prototypical organic semiconductor para-sexiphenyl (6P) adsorbed on In 2O 3(111), the thermodynamically most stable surface of the material that the most common transparent conducting oxide, indium tin oxide, is based on. The onset of nucleation and formation of the first monolayermore » are followed with atomically resolved scanning tunneling microscopy and noncontact atomic force microscopy (nc-AFM). Annealing to 200 °C provides sufficient thermal energy for the molecules to orient themselves along the high-symmetry directions of the surface, leading to a single adsorption site. The AFM data suggests an essentially planar adsorption geometry. With increasing coverage, the 6P molecules first form a loose network with a poor long-range order. Eventually, the molecules reorient into an ordered monolayer. In conclusion, this first monolayer has a densely packed, well-ordered (2 × 1) structure with one 6P per In 2O 3(111) substrate unit cell, that is, a molecular density of 5.64 × 10 13 cm –2.« less

Prototypical Organic–Oxide Interface: Intramolecular Resolution of Sexiphenyl on In 2O 3 (111)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, Margareta; Hofinger, Jakob; Setvin, Martin

The performance of an organic semiconductor device is critically determined by the geometric alignment, orientation, and ordering of the organic molecules. Although an organic multilayer eventually adopts the crystal structure of the organic material, the alignment and configuration at the interface with the substrate/electrode material are essential for charge injection into the organic layer. This work focuses on the prototypical organic semiconductor para-sexiphenyl (6P) adsorbed on In 2O 3(111), the thermodynamically most stable surface of the material that the most common transparent conducting oxide, indium tin oxide, is based on. The onset of nucleation and formation of the first monolayermore » are followed with atomically resolved scanning tunneling microscopy and noncontact atomic force microscopy (nc-AFM). Annealing to 200 °C provides sufficient thermal energy for the molecules to orient themselves along the high-symmetry directions of the surface, leading to a single adsorption site. The AFM data suggests an essentially planar adsorption geometry. With increasing coverage, the 6P molecules first form a loose network with a poor long-range order. Eventually, the molecules reorient into an ordered monolayer. In conclusion, this first monolayer has a densely packed, well-ordered (2 × 1) structure with one 6P per In 2O 3(111) substrate unit cell, that is, a molecular density of 5.64 × 10 13 cm –2.« less

Portable 4.6 Micrometers Laser Absorption Spectrometer for Carbon Monoxide Monitoring and Fire Detection

NASA Technical Reports Server (NTRS)

Briggs, Ryan M.; Frez, Clifford; Forouhar, Siamak; May, Randy D.; Ruff, Gary A.

2013-01-01

The air quality aboard manned spacecraft must be continuously monitored to ensure crew safety and identify equipment malfunctions. In particular, accurate real-time monitoring of carbon monoxide (CO) levels helps to prevent chronic exposure and can also provide early detection of combustion-related hazards. For long-duration missions, environmental monitoring grows in importance, but the mass and volume of monitoring instruments must be minimized. Furthermore, environmental analysis beyond low-Earth orbit must be performed in-situ, as sample return becomes impractical. Due to their small size, low power draw, and performance reliability, semiconductor-laser-based absorption spectrometers are viable candidates for this purpose. To reduce instrument form factor and complexity, the emission wavelength of the laser source should coincide with strong fundamental absorption lines of the target gases, which occur in the 3 to 5 micrometers wavelength range for most combustion products of interest, thereby reducing the absorption path length required for low-level concentration measurements. To address the needs of current and future NASA missions, we have developed a prototype absorption spectrometer using a semiconductor quantum cascade laser source operating near 4.6 micrometers that can be used to detect low concentrations of CO with a compact single-pass absorption cell. In this study, we present the design of the prototype instrument and report on measurements of CO emissions from the combustion of a variety of aerospace plastics.

Glove perforations during open surgery for gynaecological malignancies.

PubMed

Manjunath, A P; Shepherd, J H; Barton, D P J; Bridges, J E; Ind, T E J

2008-07-01

To audit glove perforations at laparotomies for gynaecological cancers. Gynaecological oncology unit, cancer centre, London. Prospective audit. Twenty-nine laparotomies for gynaecological cancers over 3 months. Gloves used during laparotomies for gynaecological cancer were tested for perforations by the air inflation and water immersion technique. Parameters recorded were: type of procedure, localisation of perforation, type of gloves, seniority of surgeon, operation time and awareness of perforations. Glove perforation rate. Perforations were found in gloves from 27/29 (93%) laparotomies. The perforation rate was 61/462 (13%) per glove. The perforation rate was three times higher when the duration of surgery was more than 5 hours. The perforation rate was 63% for primary surgeons, 54.5% for first assistant, 4.7% for second assistant and 40.5% for scrub nurses. Clinical fellows were at highest risk of injury (94%). Two-thirds of perforations were on the index finger or thumb. The glove on the nondominant hand had perforations in 54% of cases. In 50% of cases, the participants were not aware of the perforations. There were less inner glove perforations in double gloves compared with single gloves (5/139 versus 26/154; P = 0.0004, OR = 5.4, 95% CI 1.9-16.7). The indicator glove system failed to identify holes in 44% of cases. Glove perforations were found in most (93%) laparotomies for gynaecological malignancies. They are most common among clinical fellows, are often unnoticed and often not detected by the indicator glove system.

Optimizing time management after perforation by colonoscopy results in better outcome for the patients.

PubMed

Rumstadt, Bernhard; Schilling, Dieter

2008-01-01

Perforation during colonoscopy is a rare but severe complication. The aim of this study was to assess the time management and laparoscopic therapy of this complication and to evaluate patient outcomes. A retrospective analysis was done on 15 patients operated for a perforation from colonoscopy between January 2000 and December 2006. Three perforations occurred during diagnostic and 12 perforations during interventional colonoscopy. Two perforations occurred as transmural thermal injury to the colon wall. Peritonitis was found in 4 cases and significantly correlated with the mean time between perforation and operation. Twelve perforations were oversewn laparoscopically and 3 perforations were oversewn by laparotomy. After laparoscopic treatment, hospital stay was significantly shorter than after laparotomy. One patient had a postoperative wound infection, mortality was 0%. Laparoscopic oversewing is a safe and effective method in the treatment of perforation from colonoscopy. Optimizing the time range between perforation and laparoscopic therapy results in a better outcome for the patients.

Glove perforation rate in open lung surgery.

PubMed

Hollaus, P H; Lax, F; Janakiev, D; Wurnig, P N; Pridun, N S

1999-04-01

In open lung surgery the surgical access is encircled by the ribs, which should result in a high glove perforation rate compared with other surgical specialities. Prospectively the surgeon, first and second assistant and the scrub nurse wore double standard latex gloves during 100 thoracotomies. Parameters recorded were: procedure performed, number of perforations, localization of perforation, the seniority of the surgeon, manoeuvre performed at the moment of perforation, immediate cause of perforation, operation time, performance of rib resection during thoracotomy and time of occurrence of the first three perforations. One thousand, six hundred and seventy-three gloves (902 outer, 771 inner) were tested. In 78 operations perforations occurred. There were 150 outer glove perforations (8.9%, 0-8, mean 1.23), 19 inner glove perforations (1.13%, 0-2, mean 0.19). Cutaneous blood exposure was prevented in 78% of all operations and in 87% of all perforations. The perforation rate for the surgeon, the scrub nurse, the first and the second assistant were 61.2, 40.4, 9.7 and 3.1% of all operations, respectively. Rib resection and a duration of more than 2 h resulted in a significant rise of glove perforation rate (P<0.05). The personal experience of the surgeon and the type of operation did not correlate with glove perforation. The immediate cause leading to perforation was named in only 17 cases (13.7%) and comprised contact with bone (seven), a needle stitch (seven) and a production flaw (three). Leaks were localized mostly on the first finger (18%),second finger, (39%) palm and dorsum of the hand (16%). The average occurrence of all first perforations was 38.7 min (range 3-190) after the beginning of surgery, the second after 63.2 min (range 10-195). Fifty-four first perforations (50.5%) were found during the first 30 min of the operation. The reported perforation rate of 78% lies in the highest range of reported perforation rates in different surgical specialities. Double gloving effectively prevented cutaneous blood exposure and thus should become a routine for the thoracic surgeon to prevent transmission of infectious diseases from the patient to the surgeon.

Application of Posterior Thigh Three-Dimensional Profunda Artery Perforator Perforasomes in Refining Next-Generation Flap Designs: Transverse, Vertical, and S-Shaped Profunda Artery Perforator Flaps.

PubMed

Mohan, Anita T; Zhu, Lin; Sur, Yoo Joon; Morsy, Mohamed; Michalak, Gregory J; Lachman, Nirusha; Rammos, Charalambos K; Saint-Cyr, Michel

2017-04-01

This study aimed to delineate and compare the hot spots and three-dimensional vascular territories of dominant profunda artery perforators in the posterior thigh region, and modifications in flap design are discussed. Twenty-nine posterior thigh flaps were raised in fresh cadaveric specimens, and profunda artery perforators were documented. Dominant perforators were injected with iodinated contrast to assess perforasomes using computed tomographic angiography. Analysis with three-dimensional rendering and volume calculations of perfusion patterns was performed. In total, 316 perforators were mapped and 33 perforators were injected for analysis. The hot spot for dominant perforators was the proximal medial quadrant, 5 to 10 cm from the inferior gluteal crease, with two smaller hot spots in the upper lateral and distal posterior midline. Although 69 percent were musculocutaneous, distal perforators were predominantly septocutaneous in the posterior midline, 5 to 8 cm from the popliteal crease. Proximal perforators were classified into first (most proximal) and second perforators, and their median perforasome was 233 and 286.4 cm, respectively (p = 0.86). There were no significant differences between proximal and distal perforators in perforasome surface areas, percentage areas perfused, and perforasome volumes. Large linking vessel networks were attributed to a broader perforasome and greater overlap between adjacent or distal perforators. Dominant linking vessels and recurrent flow through the subdermal plexus contribute to the robust vascular supply of profunda artery perforator flaps. Posterior thigh region perforator hot spots and their perfusion characteristics can inform the potential limits, orientation, and modifications of flap or skin paddle designs.

Towards point of care testing for C. difficile infection by volatile profiling, using the combination of a short multi-capillary gas chromatography column with metal oxide sensor detection

NASA Astrophysics Data System (ADS)

McGuire, N. D.; Ewen, R. J.; de Lacy Costello, B.; Garner, C. E.; Probert, C. S. J.; Vaughan, K.; Ratcliffe, N. M.

2014-06-01

Rapid volatile profiling of stool sample headspace was achieved using a combination of short multi-capillary chromatography column (SMCC), highly sensitive heated metal oxide semiconductor sensor and artificial neural network software. For direct analysis of biological samples this prototype offers alternatives to conventional gas chromatography (GC) detectors and electronic nose technology. The performance was compared to an identical instrument incorporating a long single capillary column (LSCC). The ability of the prototypes to separate complex mixtures was assessed using gas standards and homogenized in house ‘standard’ stool samples, with both capable of detecting more than 24 peaks per sample. The elution time was considerably faster with the SMCC resulting in a run time of 10 min compared to 30 min for the LSCC. The diagnostic potential of the prototypes was assessed using 50 C. difficile positive and 50 negative samples. The prototypes demonstrated similar capability of discriminating between positive and negative samples with sensitivity and specificity of 85% and 80% respectively. C. difficile is an important cause of hospital acquired diarrhoea, with significant morbidity and mortality around the world. A device capable of rapidly diagnosing the disease at the point of care would reduce cases, deaths and financial burden.

Towards point of care testing for C. difficile infection by volatile profiling, using the combination of a short multi-capillary gas chromatography column with metal oxide sensor detection

PubMed Central

McGuire, N D; Ewen, R J; de Lacy Costello, B; Garner, C E; Probert, C S J; Vaughan, K.; Ratcliffe, N M

2016-01-01

Rapid volatile profiling of stool sample headspace was achieved using a combination of short multi-capillary chromatography column (SMCC), highly sensitive heated metal oxide semiconductor (MOS) sensor and artificial neural network (ANN) software. For direct analysis of biological samples this prototype offers alternatives to conventional GC detectors and electronic nose technology. The performance was compared to an identical instrument incorporating a long single capillary column (LSCC). The ability of the prototypes to separate complex mixtures was assessed using gas standards and homogenised in house ‘standard’ stool samples, with both capable of detecting more than 24 peaks per sample. The elution time was considerably faster with the SMCC resulting in a run time of 10 minutes compared to 30 minutes for the LSCC. The diagnostic potential of the prototypes was assessed using 50 C. difficile positive and 50 negative samples. The prototypes demonstrated similar capability of discriminating between positive and negative samples with sensitivity and specificity of 85% and 80% respectively. C. difficile is an important cause of hospital acquired diarrhoea, with significant morbidity and mortality around the world. A device capable of rapidly diagnosing the disease at the point of care would reduce cases, deaths and financial burden. PMID:27212803

Investigation on the Acoustic Absorption of Flexible Micro-Perforated Panel with Ultra-Micro Perforations

NASA Astrophysics Data System (ADS)

Li, Guoxin; Tang, Xiaoning; Zhang, Xiaoxiao; Qian, Y. J.; Kong, Deyi

2017-11-01

Flexible micro-perforated panel has unique advantages in noise reduction due to its good flexibility compared with traditional rigid micro-perforated panel. In this paper, flexible micro-perforated panel was prepared by computer numerical control (CNC) milling machine. Three kinds of plastics including polyvinylchloride (PVC), polyethylene terephthalate (PET), and polyimide (PI) were taken as the matrix materials to prepare flexible micro-perforated panel. It has been found that flexible micro-perforated panel made of PET possessing good porosity and proper density, elastic modulus and poisson ratio exhibited the best acoustic absorption properties. The effects of various structural parameters including perforation diameter, perforation ratio, thickness and air gap have also been investigated, which would be helpful to the optimization of acoustic absorption properties.

The three-dimensional simulation analysis of dynamic response on perforated strings

NASA Astrophysics Data System (ADS)

Li, M. F.; Liu, H. F.; Dou, Y. H.; Cao, L. H.; Liu, Y. X.

2018-06-01

It analyzes the dynamic response and stresses of perforating tubular string to detonating impact load in oil-gas well in ANSYS, obtains the response of vibration displacement, velocity and acceleration of perforating tubularstring caused by detonating impact load, finds the influence of the length and wall thickness of perforating tubular string to working stresses. The result shows that:when the detonating impact load exerts the perforating tubular string with compressive and tensile axial force alternatively;the vibration displacement, velocity and acceleration of perfora-ting tubular string change periodically at same cycle;the closer to the perforating gun, the larger the amplitude of vi-bration velocity and acceleration;the closer to the packer the smaller the vibration displacement, the larger the work-ing equivalent stress of perforating tubular string;the longer or the thicker the perforating tubular string, the smaller the working equivalent stress and the higher the strength safety. Therefore, it uses the damping tube between packer and perforating gun as well as thick walled tubing to increase the strength safety of perforating tubular string.

Research on the Perforating Algorithm Based on STL Files

NASA Astrophysics Data System (ADS)

Yuchuan, Han; Xianfeng, Zhu; Yunrui, Bai; Zhiwen, Wu

2018-04-01

In the process of making medical personalized external fixation brace, the 3D data file should be perforated to increase the air permeability and reduce the weight. In this paper, a perforating algorithm for 3D STL file is proposed, which can perforate holes, hollow characters and engrave decorative patterns on STL files. The perforating process is composed of three steps. Firstly, make the imaginary space surface intersect with the STL model, and reconstruct triangles at the intersection. Secondly, delete the triangular facets inside the space surface and make a hole on the STL model. Thirdly, triangulate the inner surface of the hole, and thus realize the perforating. Choose the simple space equations such as cylindrical and rectangular prism equations as perforating equations can perforate round holes and rectangular holes. Through the combination of different holes, lettering, perforating decorative patterns and other perforated results can be accomplished. At last, an external fixation brace and an individual pen container were perforated holes using the algorithm, and the expected results were reached, which proved the algorithm is feasible.

Synthesis, fabrication and characterization of Ge/Si axial nanowire heterostructure tunnel FETs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Picraux, Samuel T; Dayeh, Shadi A

2010-01-01

Axial Ge/Si heterostructure nanowires allow energy band-edge engineering along the axis of the nanowire, which is the charge transport direction, and the realization of asymmetric devices for novel device architectures. This work reports on two advances in the area of heterostructure nanowires and tunnel FETs: (i) the realization of 100% compositionally modulated Si/Ge axial heterostructure nanowires with lengths suitable for device fabrication and (ii) the design and implementation of Schottky barrier tunnel FETs on these nanowires for high-on currents and suppressed ambipolar behavior. Initial prototype devices resulted in a current drive in excess of 100 {micro}A/{micro}m (I/{pi}D) and 10{sup 5}more » I{sub on}/I{sub off} ratios. These results demonstrate the potential of such asymmetric heterostructures (both in the semiconductor channel and metal-semiconductor barrier heights) for low-power and high performance electronics.« less

A Knowledge Database on Thermal Control in Manufacturing Processes

NASA Astrophysics Data System (ADS)

Hirasawa, Shigeki; Satoh, Isao

A prototype version of a knowledge database on thermal control in manufacturing processes, specifically, molding, semiconductor manufacturing, and micro-scale manufacturing has been developed. The knowledge database has search functions for technical data, evaluated benchmark data, academic papers, and patents. The database also displays trends and future roadmaps for research topics. It has quick-calculation functions for basic design. This paper summarizes present research topics and future research on thermal control in manufacturing engineering to collate the information to the knowledge database. In the molding process, the initial mold and melt temperatures are very important parameters. In addition, thermal control is related to many semiconductor processes, and the main parameter is temperature variation in wafers. Accurate in-situ temperature measurment of wafers is important. And many technologies are being developed to manufacture micro-structures. Accordingly, the knowledge database will help further advance these technologies.

Uncertain behaviours of integrated circuits improve computational performance.

PubMed

Yoshimura, Chihiro; Yamaoka, Masanao; Hayashi, Masato; Okuyama, Takuya; Aoki, Hidetaka; Kawarabayashi, Ken-ichi; Mizuno, Hiroyuki

2015-11-20

Improvements to the performance of conventional computers have mainly been achieved through semiconductor scaling; however, scaling is reaching its limitations. Natural phenomena, such as quantum superposition and stochastic resonance, have been introduced into new computing paradigms to improve performance beyond these limitations. Here, we explain that the uncertain behaviours of devices due to semiconductor scaling can improve the performance of computers. We prototyped an integrated circuit by performing a ground-state search of the Ising model. The bit errors of memory cell devices holding the current state of search occur probabilistically by inserting fluctuations into dynamic device characteristics, which will be actualised in the future to the chip. As a result, we observed more improvements in solution accuracy than that without fluctuations. Although the uncertain behaviours of devices had been intended to be eliminated in conventional devices, we demonstrate that uncertain behaviours has become the key to improving computational performance.

An overview of silicon carbide device technology

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Matus, Lawrence G.

1992-01-01

Recent progress in the development of silicon carbide (SiC) as a semiconductor is briefly reviewed. This material shows great promise towards providing electronic devices that can operate under the high-temperature, high-radiation, and/or high-power conditions where current semiconductor technologies fail. High quality single crystal wafers have become available, and techniques for growing high quality epilayers have been refined to the point where experimental SiC devices and circuits can be developed. The prototype diodes and transistors that have been produced to date show encouraging characteristics, but by the same token they also exhibit some device-related problems that are not unlike those faced in the early days of silicon technology development. Although these problems will not prevent the implementation of some useful circuits, the performance and operating regime of SiC electronics will be limited until these device-related issues are solved.

Photoactivated and patternable charge transport materials and their use in organic light-emitting devices

NASA Astrophysics Data System (ADS)

Liu, Jie; Lewis, Larry N.; Duggal, Anil R.

2007-06-01

Organic light-emitting devices (OLEDs) usually employ at least one organic semiconductor layer that acts as a hole-injection material. The prototypical example is a conjugated polymer such as poly(3,4-ethylenedioxythiophene) heavily p doped with polystyrene sulfonic acid. Here, the authors describe a chemical doping strategy for hole injection material formulation that enables spatial patterning of the material conductivity through optical activation. The strategy utilizes an organic photoacid generator (PAG) dispersed in a polymeric organic semiconductor host. Upon UV irradiation, the PAG decomposes and generates a strong protonic acid that subsequently p dopes the host. The authors demonstrate an OLED made with such a light-activated hole-injection material and show that arbitrary emission patterning can be accomplished. This approach may provide a simple, low cost path toward specialty lighting and signage applications for OLED technology.

One-dimensional quantum matter: gold-induced nanowires on semiconductor surfaces

NASA Astrophysics Data System (ADS)

Dudy, L.; Aulbach, J.; Wagner, T.; Schäfer, J.; Claessen, R.

2017-11-01

Interacting electrons confined to only one spatial dimension display a wide range of unusual many-body quantum phenomena, ranging from Peierls instabilities to the breakdown of the canonical Fermi liquid paradigm to even unusual spin phenomena. The underlying physics is not only of tremendous fundamental interest, but may also have bearing on device functionality in future micro- and nanoelectronics with lateral extensions reaching the atomic limit. Metallic adatoms deposited on semiconductor surfaces may form self-assembled atomic nanowires, thus representing highly interesting and well-controlled solid-state realizations of such 1D quantum systems. Here we review experimental and theoretical investigations on a few selected prototypical nanowire surface systems, specifically Ge(0 0 1)-Au and Si(hhk)-Au, and the search for 1D quantum states in them. We summarize the current state of research and identify open questions and issues.

Bifacial PV cell with reflector for stand-alone mast for sensor powering purposes

NASA Astrophysics Data System (ADS)

Jakobsen, Michael L.; Thorsteinsson, Sune; Poulsen, Peter B.; Riedel, N.; Rødder, Peter M.; Rødder, Kristin

2017-09-01

Reflectors to bifacial PV-cells are simulated and prototyped in this work. The aim is to optimize the reflector to specific latitudes, and particularly northern latitudes. Specifically, by using minimum semiconductor area the reflector must be able to deliver the electrical power required at the condition of minimum solar travel above the horizon, worst weather condition etc. We will test a bifacial PV-module with a retroreflector, and compare the output with simulations combined with local solar data.

Analysis of a modular generator for high-voltage, high-frequency pulsed applications, using low voltage semiconductors (< 1 kV) and series connected step-up (1:10) transformers.

PubMed

Redondo, L M; Fernando Silva, J; Margato, E

2007-03-01

This article discusses the operation of a modular generator topology, which has been developed for high-frequency (kHz), high-voltage (kV) pulsed applications. The proposed generator uses individual modules, each one consisting of a pulse circuit based on a modified forward converter, which takes advantage of the required low duty cycle to operate with a low voltage clamp reset circuit for the step-up transformer. This reduces the maximum voltage on the semiconductor devices of both primary and secondary transformer sides. The secondary winding of each step-up transformer is series connected, delivering a fraction of the total voltage. Each individual pulsed module is supplied via an isolation transformer. The assembled modular laboratorial prototype, with three 5 kV modules, 800 V semiconductor switches, and 1:10 step-up transformers, has 80% efficiency, and is capable of delivering, into resistive loads, -15 kV1 A pulses with 5 micros width, 10 kHz repetition rate, with less than 1 micros pulse rise time. Experimental results for resistive loads are presented and discussed.

Quantum Confined Semiconductors for High Efficiency Photovoltaics

NASA Astrophysics Data System (ADS)

Beard, Matthew

2014-03-01

Semiconductor nanostructures, where at least one dimension is small enough to produce quantum confinement effects, provide new pathways for controlling energy flow and therefore have the potential to increase the efficiency of the primary photon-to-free energy conversion step. In this discussion, I will present the current status of research efforts towards utilizing the unique properties of colloidal quantum dots (NCs confined in three dimensions) in prototype solar cells and demonstrate that these unique systems have the potential to bypass the Shockley-Queisser single-junction limit for solar photon conversion. The solar cells are constructed using a low temperature solution based deposition of PbS or PbSe QDs as the absorber layer. Different chemical treatments of the QD layer are employed in order to obtain good electrical communication while maintaining the quantum-confined properties of the QDs. We have characterized the transport and carrier dynamics using a transient absorption, time-resolved THz, and temperature-dependent photoluminescence. I will discuss the interplay between carrier generation, recombination, and mobility within the QD layers. A unique aspect of our devices is that the QDs exhibit multiple exciton generation with an efficiency that is ~ 2 to 3 times greater than the parental bulk semiconductor.

Origin of spin gapless semiconductor behavior in CoFeCrGa: Theory and Experiment

DOE PAGES

Bainsla, Lakhan; Mallick, A. I.; Raja, M. Manivel; ...

2015-07-08

Despite a plethora of materials suggested for spintronic applications, a new class of materials has emerged, namely spin gapless semiconductors (SGS), which offers potentially more advantageous properties than existing ones. These magnetic semiconductors exhibit a finite band gap for one spin channel and a closed gap for the other. Supported by electronic-structure calculations, we report evidence of SGS behavior in equiatomic quaternary CoFeCrGa, having a cubic Heusler (prototype LiMgPdSn) structure but exhibiting chemical disorder (DO 3 structure). CoFeCrGa is found to transform from SGS to half-metallic phase under pressure, which is attributed to unique electronic-structure features. The saturation magnetization (Mmore » S) was obtained at 8K agrees with the Slater-Pauling rule and the Curie temperature (T C) is found to exceed 400K. Carrier concentration (up to 250K) and electrical conductivity are observed to be nearly temperature independent, prerequisites for SGS. The anomalous Hall coefficient is estimated to be 185S/cm at 5K. Considering the SGS properties and high T C, this material appears to be promising for spintronic applications.« less

Lack of utility of measuring serum bilirubin concentration in distinguishing perforation status of pediatric appendicitis.

PubMed

Bonadio, William; Bruno, Santina; Attaway, David; Dharmar, Logesh; Tam, Derek; Homel, Peter

2017-06-01

Pediatric appendicitis is a common, potentially serious condition. Determining perforation status is crucial to planning effective management. Determine the efficacy of serum total bilirubin concentration [STBC] in distinguishing perforation status in children with appendicitis. Retrospective review of 257 cases of appendicitis who received abdominal CT scan and measurement of STBC. There were 109 with perforation vs 148 without perforation. Although elevated STBC was significantly more common in those with [36%] vs without perforation [22%], the mean difference in elevated values between groups [0.1mg/dL] was clinically insignificant. Higher degrees of hyperbilirubinemia [>2mg/dL] were rarely encountered [5%]. Predictive values for elevated STBC in distinguishing perforation outcome were imprecise [sensitivity 38.5%, specificity 78.4%, PPV 56.8%, NPV 63.4%]. ROC curve analysis of multiple clinical and other laboratory factors for predicting perforation status was unenhanced by adding the STBC variable. Specific analysis of those with perforated appendicitis and percutaneously-drained intra-abdominal abscess which was culture-positive for Escherichia coli showed an identical rate of STBC elevation compared to all with perforation. The routine measurement of STBC does not accurately distinguish perforation status in children with appendicitis, nor discern infecting organism in those with perforation and intra-abdominal abscess. Copyright © 2017 Elsevier Inc. All rights reserved.

The rate of glove perforations in orthopaedic procedures: single versus double gloving. A prospective study.

PubMed

Chan, K Y; Singh, V A; Oun, B H; To, B H Se

2006-12-01

Glove perforation during surgery has always been a matter of concern as it increases the infection rate and the risk of transmission of blood borne diseases. To determine the common causes, the site and the awareness of glove perforations in orthopaedic surgery, a prospective study was conducted to assess the rate of glove perforation during 130 consecutive orthopaedic operations. All gloves worn by the surgical team were assessed after the surgery using the water-loading test. A total of 1452 gloves were tested, and the rate of perforation was 3.58%. Most of these perforations (61.5%) were unnoticed. The main surgeons had the most perforations (76.9%), followed by first assistants (13.5%) and second assistants (9.6%). Most perforations occurred at the non-dominant hand. The commonest site of perforation was the index finger followed by the thumb. Shearing force with instruments accounted for 45% of the noticed perforations. Majority of these occurred during nailing procedures (33%) and internal fixation without the use of wires (19%). Our rate of glove perforation is similar to other series. Most of them went unnoticed and were mainly due to shearing injuries rather than perforation by sharps. Therefore, there is an increased risk of contamination and break in asepsis during surgery.

[Microsurgical anatomy of the perforating arteries in the superior space of the internal carotid artery through a pterional approach].

PubMed

Qi, Song-tao; Huang, Chuan-ping; Lu, Yun-tao; Pan, Jun; Fan, Jun

2007-05-01

To study the microanatomy of the perforating arteries in the superior space of the internal carotid artery visualized through a pterional approach. Twelve (24 sides) perfused cadaver heads were dissected via the pterional approach, and the perforating arteries in the superior space of the internal carotid artery were studied under microscope. The diameter, course and distribution in the anterior perforated substance of the perforating arteries were recorded. All the perforating arteries exposed lied on the side of the brain tissue. The carotid bifurcation on 8 sides had perforating arteries, and 11 sides showed medial lenticulostriate artery of the middle cerebral arteries, with short course and overlapped with another perforating arteries upon entry into the anterior perforated substance. On 4 sides, the medial lenticulostriate artery coincided with the perforating arteries in A1. All 24 sides showed middle lenticulostriate artery and lateral lenticulostriate artery of the middle cerebral arteries. Most of the lenticulostriate arteries originated from the anterior segment of the bifurcation of the middle cerebral arteries. The earlier bifurcation occurred in M1 of the middle cerebral arteries, the more perforating arteries originated. On 22 sides, the anterior cerebral arteries had perforating arteries with many branches, and fewer perforating arteries in a main artery were associated with greater diameter of them. The superior space of the internal carotid artery allows a space for operation, and in some cases, part of the medial leticulostriate arteries and A1 perforating arteries can be severed to obtain larger space for the operation.

Differentiating perforated from non-perforated appendicitis on contrast-enhanced magnetic resonance imaging.

PubMed

Rosenbaum, Daniel G; Askin, Gulce; Beneck, Debra M; Kovanlikaya, Arzu

2017-10-01

The role of magnetic resonance imaging (MRI) in pediatric appendicitis is increasing; MRI findings predictive of appendiceal perforation have not been specifically evaluated. To assess the performance of MRI in differentiating perforated from non-perforated appendicitis. A retrospective review of pediatric patients undergoing contrast-enhanced MRI and subsequent appendectomy was performed, with surgicopathological confirmation of perforation. Appendiceal diameter and the following 10 MRI findings were assessed: appendiceal restricted diffusion, wall defect, appendicolith, periappendiceal free fluid, remote free fluid, restricted diffusion within free fluid, abscess, peritoneal enhancement, ileocecal wall thickening and ileus. Two-sample t-test and chi-square tests were used to analyze continuous and discrete data, respectively. Sensitivity and specificity for individual MRI findings were calculated and optimal thresholds for measures of accuracy were selected. Seventy-seven patients (mean age: 12.2 years) with appendicitis were included, of whom 22 had perforation. The perforated group had a larger mean appendiceal diameter and mean number of MRI findings than the non-perforated group (12.3 mm vs. 8.6 mm; 5.0 vs. 2.0, respectively). Abscess, wall defect and restricted diffusion within free fluid had the greatest specificity for perforation (1.00, 1.00 and 0.96, respectively) but low sensitivity (0.36, 0.25 and 0.32, respectively). The receiver operator characteristic curve for total number of MRI findings had an area under the curve of 0.92, with an optimal threshold of 3.5. A threshold of any 4 findings had the best ability to accurately discriminate between perforated and non-perforated cases, with a sensitivity of 82% and specificity of 85%. Contrast-enhanced MRI can differentiate perforated from non-perforated appendicitis. The presence of multiple findings increases diagnostic accuracy, with a threshold of any four findings optimally discriminating between perforated and non-perforated cases. These results may help guide management decisions as MRI assumes a greater role in the work-up of pediatric appendicitis.

A Novel Perforator Flap Training Model Using a Chicken Leg.

PubMed

Cifuentes, Ignacio J; Yañez, Ricardo A; Salisbury, Maria C; Rodriguez, José R; Varas, Julian E; Dagnino, Bruno L

2016-04-01

Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg. A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised. The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes. This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training.

Spontaneous Intrahepatic Type II Gallbladder Perforation: A Rare Cause of Liver Abscess – Case Report

PubMed Central

Singh, Kumkum; Singh, Amit; Vidyarthi, Shivaji H; Jindal, Satyaprakash; Thounaojam, Chandra Kumar

2013-01-01

A liver abscess formation is a rare complication of a gallbladder perforation, with a cholecystohepatic communication. Niemeier, in 1934, classified free gallbladder perforations and generalised biliary peritonitis as an acute or a Type I gallbladder perforation, a pericholecystic abscess and localised peritonitis as a subacute or a Type II gallbladder perforation, and cholecystoenteric fistulas as chronic or Type III gallbladder perforations. We are describing a 50–year–old male patient who presented with right upper quadrant pain and was found to have an intrahepatic perforation of the gallbladder. Our patient had a Type II perforation. We have discussed the diagnostic work-up and the management of this rare entity. Due to the high mortality that can be caused by a delay in making the correct diagnosis, a gallbladder perforation represents a special diagnostic and surgical challenge. PMID:24179927

Intercostal artery perforator propeller flap for reconstruction of trunk defects following sarcoma resection.

PubMed

Zang, Mengqing; Yu, Shengji; Xu, Libin; Zhao, Zhenguo; Zhu, Shan; Ding, Qiang; Liu, Yuanbo

2015-06-01

Trunk defects following soft tissue sarcoma resection are usually managed by myocutaneous flaps or free flaps. However, harvesting muscle will cause functional morbidities and some trunk regions lack reliable recipient vessels. The intercostal arteries give off multiple perforators, which distribute widely over the trunk and can supply various pedicle flaps. Our purpose is to use various intercostal artery perforator propeller flaps for trunk oncologic reconstruction. Between November 2013 and July 2014, nine intercostal artery perforator propeller flaps were performed in seven patients to reconstruct the defects following sarcoma resection in different regions of the trunk, including the back, lumbar, chest, and abdomen. Two perforators from intercostal arteries were identified for each flap using Doppler ultrasound probe adjacent to the defect. The perforator with visible pulsation was chosen as the pedicle vessel. An elliptical flap was raised and rotated in a propeller fashion to repair the defects. There were one dorsal intercostal artery perforator flap, four dorsolateral intercostal artery perforator flaps, three lateral intercostal artery perforator flaps, and one anterior intercostal artery perforator flap. The mean skin paddle dimension was 9.38 cm in width (range 6-14 cm) and 21.22 cm in length (range 13-28 cm). All intercostal artery perforator flaps survived completely, except for marginal necrosis in one flap harvested close to the previous flap donor site. The intercostal artery perforator propeller flap provides various and valuable options in our reconstructive armamentarium for trunk oncologic reconstruction. To our knowledge, this is the first case series of using intercostal artery perforator propeller flaps for trunk oncologic reconstruction and clinical application of dorsolateral intercostal artery perforator flaps. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

The Use of Magnetic Resonance Imaging in Planning a Pedicled Perforator Flap for Pressure Sores in the Gluteal Region.

PubMed

Park, Sun-June; Lee, Kyeong-Tae; Jeon, Byung-Joon; Woo, Kyong-Je

2018-04-01

Pedicled perforator flaps (PPFs) have been widely used to treat pressure sores in the gluteal region. Selection of a reliable perforator is crucial for successful surgical treatment of pressure sores using PPFs. In this study, we evaluate the role of magnetic resonance imaging (MRI) in planning PPF reconstruction of pressure sores in the gluteal region. A retrospective chart review was performed in patients who had undergone these PPF reconstructions and who had received preoperative MRI. Preoperatively, the extent of infection and necrotic tissue was evaluated using MRI, and a reliable perforator was identified, considering the perforator location in relation to the defect, perforator size, and perforator courses. Intraoperatively, the targeted perforator was marked on the skin at the locations measured on the MRI images, and the marked location was confirmed using intraoperative handheld Doppler. Superior gluteal artery, inferior gluteal artery, or parasacral perforators were used for the PPFs. Surgical outcomes were evaluated. A total of 12 PPFs were performed in 12 patients. Superior gluteal artery perforator flaps were performed in 7 patients, inferior gluteal artery perforator flaps were performed in 3 patients, and parasacral perforator flaps were performed in 2 patients. We could identify a reliable perforator on MRI, and it was found at the predicted locations in all cases. There was only one case of partial flap necrosis. There was no recurrence of the pressure sores during the mean follow-up period of 6.7 months (range = 3-15 months). In selected patients with gluteal pressure sores, MRI is a suitable means for not only providing information about disease extent and comorbidities but also for evaluating perforators for PPF reconstructions.

Paramuscular perforators in DIEAP flap for breast reconstruction.

PubMed

Pons, Gemma; Masia, Jaume; Sanchez-Porro, Lídia; Larrañaga, Jose; Clavero, Juan Angel

2014-12-01

One of the main steps in perforator flap surgery is to identify the dominant perforator. Using multidetector row computed tomography (MDCT) for the preoperative planning of deep inferior epigastric artery perforator (DIEAP) flap surgery, we identified a perforator with a large caliber, an excellent location in the middle abdominal region, and a totally extramuscular trajectory in a significant number of patients. We describe the frequency of this perforator and determine its characteristics. We conducted a retrospective study of 482 patients who underwent 526 DIEAP flaps for breast reconstruction from October 2003 to October 2011. Mean age at surgery was 51.3 years old. A preoperative MDCT of abdominal vascularization was performed in all patients. MDCT identified a dominant perforator with a paramuscular course in 12.4% of abdominal walls. In all cases, it was located in the midline and emerged directly from the deep inferior epigastric system. Its mean caliber was 1.9 mm. The flap was harvested based on this perforator in all these patients, and mean harvest time was 51 minutes. The characteristics of this perforator made dissection easier and reduced morbidity at the donor site. There were no flap losses and the only complications were minor. We located a paramuscular perforator in 12.4% of patients undergoing breast reconstruction with abdominal perforator flaps. Its morphological features and extramuscular course make it the perforator of choice in DIEAP flap surgery.

[Localization of perforators in the lower leg by digital antomy imaging methods].

PubMed

Wei, Peng; Ma, Liang-Liang; Fang, Ye-Dong; Xia, Wei-Zhi; Ding, Mao-Chao; Mei, Jin

2012-03-01

To offer both the accurate three-dimensional anatomical information and algorithmic morphology of perforators in the lower leg for perforator flaps design. The cadaver was injected with a modified lead oxide-gelatin mixture. Radiography was first performed and the images were analyzed using the software Photoshop and Scion Image. Then spiral CT scan was also performed and 3-dimensional images were reconstructed with MIMICS 10.01 software. There are (27 +/- 4) perforators whose outer diameter > or = 0.5 mm ( average, 0.8 +/- 0.2 mm). The average pedicle length within the superficial fascia is (37.3 +/- 18.6) mm. The average supplied area of each perforator is (49.5 +/- 25.5) cm2. The three-dimensional model displayed accurate morphology structure and three-dimensional distribution of the perforator-to- perforator and perforator-to-source artery. The 3D reconstruction model can clearly show the geometric, local details and three-dimensional distribution. It is a considerable method for the study of morphological characteristics of the individual perforators in human calf and preoperative planning of the perforator flap.

Multiple, Pan-Enteric Perforation Secondary to Intestinal Tuberculosis

PubMed Central

Masood, Irfan; Majid, Zain; Rafiq, Ali; Rind, Waqas; Zia, Aisha; Raza, Sajjad

2015-01-01

Free perforation is one of the most feared complications of the intestinal tuberculosis. The terminal ileum is the most common site of perforation, while the majority of (90%) perforations are solitary. Herein, we describe a case of a 25-year-old male who presented with generalized peritonitis requiring an emergency exploratory laparotomy, which revealed pan-enteric perforation characterized by multiple perforations of the small bowel extending 10–15 cm from the DJ flexure up to the terminal ileum. The perforations were primarily closed, while 6–8 cm of the diseased terminal ileum was resected and the two ends were brought out as double-barreled ostomy. To the best of our knowledge, such an extensive tuberculous perforation of the small bowel has not been previously reported in the literature before. PMID:26798540

Small Tympanic Membrane Perforations in the Inferior Quadrants Do Not Impact the Manubrium Vibration in Guinea Pigs

PubMed Central

Zhang, Xiuling; Dai, Yanhong; Zhang, Shuyi; She, Wandong; Du, Xiaoping; Shui, Xiuji

2012-01-01

Background It has been believed that location of the perforation has a significant impact on hearing loss. However, recent studies have demonstrated that the perforation sites had no impact on hearing loss. We measured the velocity and pattern of the manubrium vibration in guinea pigs with intact and perforated eardrum using a laser Doppler vibrometer in order to determine the effects of different location perforations on the middle ear transfer functions. Methods Two bullas from 2 guinea pigs were used to determine stability of the umbo velocities, and 12 bullas from six guinea pigs to determine the effects of different location perforations on sound transmission. The manubrium velocity was measured at three points on the manubrium in the frequencies of 0.5–8 kHz before and after a perforation was made. The sites of perforations were in anterior-inferior (AI) quadrants of left ears and posterior-inferior (PI) quadrants of right ears. Results The manubrium vibration velocity losses were noticed in the perforated ears only below 1.5 kHz. The maximum velocity loss was about 7 dB at 500 Hz with the PI perforation. No significant difference in the velocity loss was found between AI and PI perforations. The average ratio of short process velocity to the umbo velocity was approximately 0.5 at all frequencies. No significant differences were found before and after perforation at all frequencies (p>0.05) except 7 kHz (p = 0.004) for both AI and PI perforations. Conclusions The manubrium vibration velocity losses from eardrum perforation were frequency-dependent and the largest losses occur at low frequencies. Manubrium velocity losses caused by small acute inferior perforations in guinea pigs have no significant impact on middle ear sound transmission at any frequency tested. The manubrium vibration axis may be perpendicular to the manubrium below 8 kHz in guinea pigs. PMID:22238584

Insufficient Lymph Node Sampling in Patients with Colorectal Cancer Perforation is Associated with an Adverse Oncological Outcome.

PubMed

Sugawara, Kotaro; Kawaguchi, Yoshikuni; Nomura, Yukihiro; Koike, Daisuke; Nagai, Motoki; Tanaka, Nobutaka

2017-01-01

The impact of lymph node (LN) dissection on long-term outcomes for patients with colorectal cancer (CRC) perforation remains unclear. We aim to investigate factors associated with poor prognosis and recurrence in patients with CRC, with special reference to cancer perforation and LN dissection. The subjects comprised 550 patients who underwent colorectal surgery for CRC at Stage II or III (TNM classification) between February 2006 and November 2013. Short- and long-term outcomes of patients with or without CRC perforation were evaluated. We also sought risk factors on poor prognosis, focusing on LN dissection in patients with CRC perforation. A total of 508 underwent surgery for CRC without perforation (the non-perforation group) and 39 for CRC with perforation (the perforation group). Both overall survival and recurrence-free survival rates were significantly lower in the perforation group than in the non-perforation group (overall survival, P = 0.009; recurrence-free survival, P < 0.001). The relapse rates at the peritoneum (P = 0.002), lung (P = 0.007) and LNs (P = 0.021) were significantly higher in the perforation group than in the non-perforation group. Multivariable Cox proportional hazards model revealed that CRC perforation (hazard ratio [HR] 2.55, 95 % confidential interval [CI] 1.16-4.98, P = 0.022), LN dissection <12 (HR 1.83, 95 % CI 1.07-3.13, P = 0.027), and Stage III (HR 1.79, 95 % CI 1.06-3.08, P = 0.031) were significant and independent risk factors for poor prognosis. Conducting <12 LN dissections independently increased the risk of reduction in overall survival for patients with CRC perforation. Thus, radical LN dissections should be performed to improve patients' survival rates, when patients' general and surgical conditions allow.

Remarkable Enhancement of the Hole Mobility in Several Organic Small-Molecules, Polymers, and Small-Molecule:Polymer Blend Transistors by Simple Admixing of the Lewis Acid p-Dopant B(C6F5)3.

PubMed

Panidi, Julianna; Paterson, Alexandra F; Khim, Dongyoon; Fei, Zhuping; Han, Yang; Tsetseris, Leonidas; Vourlias, George; Patsalas, Panos A; Heeney, Martin; Anthopoulos, Thomas D

2018-01-01

Improving the charge carrier mobility of solution-processable organic semiconductors is critical for the development of advanced organic thin-film transistors and their application in the emerging sector of printed electronics. Here, a simple method is reported for enhancing the hole mobility in a wide range of organic semiconductors, including small-molecules, polymers, and small-molecule:polymer blends, with the latter systems exhibiting the highest mobility. The method is simple and relies on admixing of the molecular Lewis acid B(C 6 F 5 ) 3 in the semiconductor formulation prior to solution deposition. Two prototypical semiconductors where B(C 6 F 5 ) 3 is shown to have a remarkable impact are the blends of 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene:poly(triarylamine) (diF-TESADT:PTAA) and 2,7-dioctyl[1]-benzothieno[3,2-b][1]benzothiophene:poly(indacenodithiophene-co-benzothiadiazole) (C8-BTBT:C16-IDTBT), for which hole mobilities of 8 and 11 cm 2 V -1 s -1 , respectively, are obtained. Doping of the 6,13-bis(triisopropylsilylethynyl)pentacene:PTAA blend with B(C 6 F 5 ) 3 is also shown to increase the maximum hole mobility to 3.7 cm 2 V -1 s -1 . Analysis of the single and multicomponent materials reveals that B(C 6 F 5 ) 3 plays a dual role, first acting as an efficient p-dopant, and secondly as a microstructure modifier. Semiconductors that undergo simultaneous p-doping and dopant-induced long-range crystallization are found to consistently outperform transistors based on the pristine materials. Our work underscores Lewis acid doping as a generic strategy towards high performance printed organic microelectronics.

Intrauterine devices and risk of uterine perforation: current perspectives

PubMed Central

Rowlands, Sam; Oloto, Emeka; Horwell, David H

2016-01-01

Uterine perforation is an uncommon complication of intrauterine device insertion, with an incidence of one in 1,000 insertions. Perforation may be complete, with the device totally in the abdominal cavity, or partial, with the device to varying degrees within the uterine wall. Some studies show a positive association between lactation and perforation, but a causal relationship has not been established. Very rarely, a device may perforate into bowel or the urinary tract. Perforated intrauterine devices can generally be removed successfully at laparoscopy. PMID:29386934

[Preoperative CT angiography for planning free perforator flaps in breast reconstruction].

PubMed

Kuekrek, H; Müller, D; Paepke, S; Dobritz, M; Machens, H-G; Giunta, R E

2011-04-01

Preoperative Doppler ultrasonography for planning free perforator flaps is widely established to identify preoperatively perforators. The method allows one to localise the penetrating point of the perforator through the abdominal fascia. By this means it is not possible to see the intramuscular course or the position of the perforator in relation to the inferior epigastric artery. Lately the technique of computed tomographic angiography provides an opportunity for visualising the course of perforator vessels in these tissues. This paper summarises our experience with the preoperative CT angiography in our breast centre. Since spring 2009 we have reconstructed the breasts of 44 female patients by using free flaps from the lower abdominal wall. 6 of these were bilateral. In a total number of 50 breast reconstructions we used 23 deep inferior epigastric perforator (DIEP) flaps and 27 muscle-sparing transverse rectus abdominis muscle (TRAM) flaps. In addition to the preoperative ultrasonography, a CT angiography of the lower abdomen was conducted in 29 patients. On average they showed at least 2 perforators on the left as well as right abdominal sides, which could be used as flap vessels based on their signal intensity. Based on their estimated microsurgical dissection complexity, the perforator vessels could be classified into 3 groups: 1) direct perforators of category A with short intramuscular course (39%), 2) perforators with long intramuscular course of category B (50%) and 3) "turn around" perforators of category C, which pass medially around the rectus abdominis (11%). The technique of CT angiography permits a reliable preoperative visualisation of perforators in their entire course and facilitates the selection of the supplying perforator as well as the intraoperative procedure for the surgeon. The suggested classification of perforators into 3 groups simplifies the preoperative assessment of the microsurgical dissection effort. Compared to the commonly used Doppler ultrasonography there are disadvantages like the additional cost factor and the radiation exposure. However, in our experience the more detailed planning increases the safety of flap raising and reduces surgery time, so that we consider CT angiography a positive tool to facilitate free perforator flaps. © Georg Thieme Verlag KG Stuttgart · New York.

Glove perforation time and frequency in total hip arthroplasty procedures.

PubMed

Kaya, Ibrahim; Uğraş, Akin; Sungur, Ibrahim; Yilmaz, Murat; Korkmaz, Musa; Cetinus, Ercan

2012-01-01

The aim of the present study was to investigate glove perforation rate and time and evaluate the factors affecting glove perforation in total hip arthroplasty (THA). Nine hundred seventy-nine gloves used in 57 THA procedures were assessed according to the perforation. Forty-four (77.2%) procedures were primary THA and 13 (22.8%) were revision THA. Gloves were changed when perforated, become dirty with blood or blood products, and before bone cementing. All gloves were filled with water at the end of the operation and controlled for perforation. Two hundred and one surgical gloves used during scrubbing and removed after draping the patient were examined as the control group. The location (which finger), number and time of the perforation, surgery type and duration, and distribution of the perforation location according to the surgical team were assessed. Patients' mean age was 62.9 ± 14.6 (range: 33 to 97) years and the mean surgery duration was 162.9 ± 32.0 minutes. Thirty-two glove perforations were noted in 19 of the operations. Of these perforations, 28 belonged to the surgeons and first assistants. There was no significant difference between the dominant or non-dominant hand according to the location of perforations. Perforations in the first and second fingers of the gloves accounted for 81.3% of all perforations. There was no significant difference in terms of number of gloves used, perforation numbers and operation duration between the primary and revision THA procedures. Two perforated gloves (0.99%) were found in the control group and the difference between the number of perforations in the control and study groups was significant (p=0.048). We recommend the use of two pairs of gloves to avoid the risk of contamination and protect the surgical team from infectious disease in major surgeries like THA. Surgical gloves should be changed when they are excessively contaminated with surgical fluids and the surgeon and first assistant should also change their outer gloves at an average of every 90 minutes.

Low Noise Double-Sided Silicon Strip Detector for Multiple-Compton Gamma-ray Telescope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tajima, Hiroyasu

2002-12-03

A Semiconductor Multiple-Compton Telescope (SMCT) is being developed to explore the gamma-ray universe in an energy band 0.1-20 MeV, which is not well covered by the present or near-future gamma-ray telescopes. The key feature of the SMCT is the high energy resolution that is crucial for high angular resolution and high background rejection capability. We have developed prototype modules for a low noise Double-sided Silicon Strip Detector (DSSD) system which is an essential element of the SMCT. The geometry of the DSSD is optimized to achieve the lowest noise possible. A new front-end VLSI device optimized for low noise operationmore » is also developed. We report on the design and test results of the prototype system. We have reached an energy resolution of 1.3 keV (FWHM) for 60 keV and 122 keV at 0 C.« less

A Novel Perforator Flap Training Model Using a Chicken Leg

PubMed Central

Cifuentes, Ignacio J.; Yañez, Ricardo A.; Salisbury, Maria C.; Rodriguez, José R.; Varas, Julian E.; Dagnino, Bruno L.

2016-01-01

Introduction  Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg. Methods  A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised. Results  The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes. Conclusion  This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training. PMID:27616823

Acquired perforating dermatosis in a patient with chronic renal failure.

PubMed

Fernandes, Karen de Almeida Pinto; Lima, Lourenço de Azevedo; Guedes, Juliana Chaves Ruiz; Lima, Ricardo Barbosa; D'Acri, Antônio Macedo; Martins, Carlos José

2016-01-01

Perforating dermatoses are a group of skin diseases characterized by transepidermal elimination of dermal material. The disease is divided into two groups: the primary group and the secondary group. The classical or primary perforating dermatoses are subdivided into four types according to the eliminated dermal materials: Kyrle disease, perforating reactive collagenosis, elastosis perforans serpiginosa, and perforating folliculitis. The secondary form is known as acquired perforating dermatosis. The term was proposed in 1989 by Rapini to designate the perforating dermatoses affecting adult patients with systemic disease, regardless of the dermal materials eliminated. This report describes a case of the disease with elimination of collagen and elastic fibers in a patient with chronic renal failure.

Lumbar artery perforators: an anatomical study based on computed tomographic angiography imaging.

PubMed

Sommeling, Casper Emile; Colebunders, Britt; Pardon, Heleen E; Stillaert, Filip B; Blondeel, Phillip N; van Landuyt, Koenraad

2017-08-01

The free lumbar artery perforator flap has recently been introduced as a potentially valuable option for autologous breast reconstruction in a subset of patients. Up to date, few anatomical studies, exploring the lumbar region as a donor site for perforator- based flaps, have been conducted. An anatomical study of the position of the dominant lumbar artery perforator was performed, using the preoperative computed tomographic angiography images of 24 autologous breast reconstruction patients. In total, 61 dominant perforators were determined, 28 on the left and 33 on the right side. A radiologist defined the position of the perforator as coordinates in an xy-grid. Dominant perforators were shown to originate from the lumbar arteries at the level of lumbar vertebrae three or four. Remarkably, approximately 85% of these lumbar artery perforators enter the skin at 7-10 cm lateral from the midline (mean left 8.6 cm, right 8.2 cm). This study concludes a rather constant position of the dominant perforator. Therefore, preoperative-computed tomographic angiography is not always essential to find this perforator and Doppler ultrasound could be considered as an alternative, thereby carefully assessing all advantages and disadvantages inherent to either of these imaging methods.

Spectrum of perforation peritonitis in India--review of 504 consecutive cases.

PubMed

Jhobta, Rajender Singh; Attri, Ashok Kumar; Kaushik, Robin; Sharma, Rajeev; Jhobta, Anupam

2006-09-05

Perforation peritonitis is the most common surgical emergency in India. The spectrum of etiology of perforation in Tropical countries continues to be different from its Western counterpart. The objective of the study was to highlight the spectrum of perforation peritonitis as encountered by us at Government Medical College and Hospital (GMCH), Chandigarh. Five hundred and four consecutive cases of perforation peritonitis over a period of five years were reviewed in terms of clinical presentation, operative findings and postoperative course retrospectively at GMCH, Chandigarh. The most common cause of perforation in our series was perforated duodenal ulcer (289 cases) followed by appendicitis (59 cases), gastrointestinal perforation due to blunt trauma abdomen (45 cases), typhoid fever (41 cases) and tuberculosis (20 cases). Despite delay in seeking medical treatment (53%), the overall mortality (10%) was favourably comparable with other published series though the overall morbidity (50%) was unusually high. In contrast to western literature, where lower gastrointestinal tract perforations predominate, upper gastrointestinal tract perforations constitute the majority of cases in India. The increasing incidence of post-traumatic gastro-enteric injuries may be due to an increase in high speed motor vehicle accidents which warrant early recognition and prompt treatment to avoid serious complications and death.

Causes and Outcomes of Esophageal Perforation in Eosinophilic Esophagitis.

PubMed

Runge, Thomas M; Eluri, Swathi; Cotton, Cary C; Burk, Caitlin M; Woosley, John T; Shaheen, Nicholas J; Dellon, Evan S

2017-10-01

To characterize patients who suffer perforation in the context of eosinophilic esophagitis (EoE) and to identify predictors of perforation. Esophageal perforation is a serious complication of EoE. We conducted a retrospective cohort study of the University of North Carolina EoE clinicopathologic database from 2001 to 2014. Subjects were included if they had an incident diagnosis of EoE and met consensus guidelines, including nonresponse to a PPI trial. Patients with EoE who had suffered perforation at any point during their course were identified, and compared with EoE cases without perforation. Multiple logistic regression was performed to determine predictors of perforation. Out of 511 subjects with EoE, 10 (2.0%) had experienced an esophageal perforation. Although those who perforated tended to have a longer duration of symptoms before diagnosis (11.4 vs. 7.0 y, P=0.13), a history of food impaction (odds ratio, 14.9; 95% confidence interval, 1.7-129.2) and the presence of a focal stricture (odds ratio, 4.6; 95% confidence interval, 1.1-19.7) were the only factors independently associated with perforation. Most perforations (80%) occurred after a prolonged food bolus impaction, and only half of individuals (5/10) carried a diagnosis of EoE at the time of perforation; none occurred after dilation. Six patients (60%) were treated with nonoperative management, and 4 (40%) required surgical repair. Esophageal perforation is a rare but serious complication of eosinophilic esophagitis, occurring in ∼2% of cases. Most episodes are due to food bolus impaction or strictures, suggesting that patients with fibrostenotic disease due to longer duration of symptoms are at increased risk.

Bladder perforations in children.

PubMed

Bakal, U; Sarac, M; Tartar, T; Ersoz, F; Kazez, A

2015-01-01

Bladder perforations in children occur due to several different reasons. In this clinical series study, we focused on bladder perforations due to the pelvic injury, and our aim also was to create awareness for a rare type of bladder injuries. This was a retrospective study of the patients who were treated in our clinic for bladder perforation between 2006 and 2011. We reviewed the documents of childhood bladder perforations, and demographic and clinical characteristics of the patients were obtained. No statistical analyses were used because of the limited number of cases. There were ten patients who suffered from bladder perforation in 5-year period; 5 were male, and 5 were female. The mean age of the patients was 4.35 years. Four patients (40%) experienced iatrogenic perforation and six patients (60%) experienced perforation due to the accident. Common symptoms were hematuria, abdominal tenderness, and inability to urinate. Three patients were diagnosed via emergency laparotomy, without any radiological examinations performed before surgery. Four patients suffered from the intraperitoneal perforation, three patients suffered from extraperitoneal injury and three of them both of intraperitoneal and extraperitoneal injuries. Mean recovery time for patients was 15 days. One patient developed a urinary tract infection and one newborn died due to accompanying morbidities. Nine patients were discharged from the hospital. If the patients had a pelvic injury, surgeons must pay attention for the bladder perforation. Isolated bladder perforations are rare, and they are generally associated with iatrogenic injuries. Clinicians should pay attention to findings such as anuria, inability to insert a urinary catheter, and free fluid in the abdomen in order to diagnose the bladder perforation in newborns. Novice surgeons should pay more attention to avoid causing iatrogenic bladder perforation during inguinal hernia repair.

Optimal contact forces to minimize cardiac perforations before, during, and/or after radiofrequency or cryothermal ablations.

PubMed

Quallich, Stephen G; Van Heel, Michael; Iaizzo, Paul A

2015-02-01

Catheter perforations remain a major clinical concern during ablation procedures for treatment of atrial arrhythmias and may lead to life-threatening cardiac tamponade. Radiofrequency (RF) ablation alters the biomechanical properties of cardiac tissue, ultimately allowing for perforation to occur more readily. Studies on the effects of cryoablation on perforation force as well as studies defining the perforation force of human tissue are limited. The purpose of this study was to investigate the required force to elicit perforation of cardiac atrial tissue after or during ablation procedures. Effects of RF or cryothermal ablations on catheter perforation forces for both swine (n = 83 animals, 530 treatments) and human (n = 8 specimens, 136 treatments) cardiac tissue were investigated. Overall average forces resulting in perforation of healthy unablated tissue were 406g ± 170g for swine and 591g ± 240g for humans. Post-RF ablation applications considerably reduced these forces to 246g ± 118g for swine and 362 ± 185g for humans (P <.001). Treatments with cryoablation did not significantly alter forces required to induce perforations. Decreasing catheter sizes resulted in a reduction in forces required to perforate the atrial wall (P <.001). Catheter perforations occurred over an array of contact forces with a minimum of 38g being observed. The swine model likely underestimates the required perforation forces relative to those of human tissues. We provide novel insights related to the comparative effects of RF and cryothermal ablations on the potential for inducing undesired punctures, with RF ablation reducing perforation force significantly. These data are insightful for physicians performing ablation procedures as well as for medical device designers. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Reaction of the lateral periodontium of dogs' teeth to contaminated and noncontaminated perforations filled with mineral trioxide aggregate.

PubMed

Holland, Roberto; Bisco Ferreira, Luciana; de Souza, Valdir; Otoboni Filho, José Arlindo; Murata, Sueli Satomi; Dezan, Eloi

2007-10-01

It has been shown that the mineral trioxide aggregate (MTA) used to seal lateral/furcal perforations stimulates the deposition of newly formed cementum. Nevertheless, when the site of the perforation is contaminated, the healing process might occur under less favorable conditions. This study evaluated the repair healing process of noncontaminated and contaminated lateral perforations filled with MTA and the effect of previously filling the contaminated perforations with a bactericidal agent. Thirty lateral root perforations were prepared in endodontically treated dog's teeth, thus forming 3 groups with 10 specimens each. In group 1 the perforations were immediately sealed with MTA. In group 2 the perforations were left open for 7 days and thereafter sealed with MTA. In group 3 the perforations were left open for 7 days, filled temporarily with a calcium hydroxide-based paste for 14 days, and then sealed with MTA. The animals were killed after 90 days, and the pieces were prepared for histomorphologic and histomicrobiologic evaluations. The statistical analysis showed that group 1 had significantly better repair than groups 2 (P < .05) and 3 (P < .05), which validates the superior results obtained when MTA was immediately used to seal root perforations. Groups 2 and 3 had statistically similar repair to each other (P > .05). There were a larger number of cases of complete or partial biologic seal in group 1 compared with the contaminated groups. It might be concluded that the lateral root perforations sealed with MTA after contamination presented worse repair than the noncontaminated, immediately sealed perforations. The temporary filling with a bactericidal agent (calcium hydroxide-based paste) did not improve the repair of perforations exposed to contamination, and the contaminated groups presented similar results to each other.

Changes in the localization of perforated peptic ulcer and its relation to gender and age of the patients throughout the last 45 years.

PubMed

Wysocki, Andrzej; Budzyński, Piotr; Kulawik, Jan; Drożdż, Włodzimierz

2011-04-01

Throughout recent decades there has been noticeable change in the incidence of peptic ulcer disease and its complications. The aim of the present study was to determine the character of changes over the last 45 years in the localization of perforation, in patient age, and in patient gender. A group of 881 patients admitted to the Second Department of General Surgery in Krakow, Poland, from 1962 to 2006 were included in the study and constituted the material for the analysis. The study was divided into three time periods (1962-1976, 1977-1991, and 1992-2006) to allow statistical analysis of trends. The general incidence of perforations of peptic ulcer did not show changes; however, the percentage of women with perforated duodenal ulcer markedly increased. Patients with perforated stomach ulcer--regardless of gender--and females suffering from perforated duodenal ulcer were, on the average, about 10 years older than males with perforated duodenal ulcers. The mean age of male and female patients with perforated duodenal ulcer over the last 45 years showed an insignificant upward trend. (1) The percentage of women with perforated duodenal ulcer continuously and statistically significantly rose. (2) Men with perforated duodenal ulcer were significantly younger than other patients. (3) The mean ages of male and female patients with perforated duodenal ulcer over the last 45 years showed an insignificant upward trend.

Duodenal perforation: an unusual complication of sickle cell anemia.

PubMed

Acıpayam, Can; Aldıç, Güliz; Akçora, Bülent; Çelikkaya, Mehmet Emin; Aşkar, Hasan; Dorum, Bayram Ali

2014-01-01

Duodenal perforation in childhood is a rare condition with a high mortality rate if not treated surgically. Primary gastroduodenal perforation is frequently associated with peptic ulcer and exhibits a positive family history. Helicobacter pylorus is the most significant agent. Secondary gastroduodenal perforation may be a finding of specific diseases, such as Crohn disease, or more rarely may be associated with diseases such as cystic fibrosis or sickle cell anemia. A 14-year-old boy presented with abdominal and back pain. The patient was operated on for acute abdomen and diagnosed with duodenal perforation. Helicobacter pylorus was negative. There was no risk factor to account for duodenal perforation other than sickle cell anemia. Surgical intervention was successful and without significant sequelae. Duodenal perforation is a rare entity described in patients with sickle cell anemia. To our knowledge, this is the first report of duodenal perforation in a patient sickle cell anemia.

Duodenal perforation: an unusual complication of sickle cell anemia

PubMed Central

Acıpayam, Can; Aldıç, Güliz; Akçora, Bülent; Çelikkaya, Mehmet Emin; Aşkar, Hasan; Dorum, Bayram Ali

2014-01-01

Duodenal perforation in childhood is a rare condition with a high mortality rate if not treated surgically. Primary gastroduodenal perforation is frequently associated with peptic ulcer and exhibits a positive family history. Helicobacter pylorus is the most significant agent. Secondary gastroduodenal perforation may be a finding of specific diseases, such as Crohn disease, or more rarely may be associated with diseases such as cystic fibrosis or sickle cell anemia. A 14-year-old boy presented with abdominal and back pain. The patient was operated on for acute abdomen and diagnosed with duodenal perforation. Helicobacter pylorus was negative. There was no risk factor to account for duodenal perforation other than sickle cell anemia. Surgical intervention was successful and without significant sequelae. Duodenal perforation is a rare entity described in patients with sickle cell anemia. To our knowledge, this is the first report of duodenal perforation in a patient sickle cell anemia. PMID:25422692

Incidence and patterns of surgical glove perforations: experience from Addis Ababa, Ethiopia.

PubMed

Bekele, Abebe; Makonnen, Nardos; Tesfaye, Lidya; Taye, Mulat

2017-03-20

Surgical glove perforation is a common event. The operating staff is not aware of the perforation until the procedure is complete, sometimes in as high as 70% of the incidences. Data from Ethiopia indicates that the surgical workforce suffers from a very surgery related accidents, however there is paucity of data regarding surgical glove perforation. The main objective is to describe the incidence and patterns of surgical glove perforation during surgical procedures and to compare the rates between emergency and elective surgeries at one of the main hospitals in Addis Ababa Ethiopia. This is a prospective study, performed at the Minilik II referral hospital, Addis Ababa. All surgical gloves worn during all major surgical procedures (Emergency and Elective) from June 1-July 20, 2016 were collected and used for the study. Standardised visual and hydro insufflation techniques were used to test the gloves for perforations. Parameters recorded included type of procedure performed, number of perforations, localisation of perforation and the roles of the surgical team. A total of 2634 gloves were tested, 1588 from elective and 1026 from emergency procedures. The total rate of perforation in emergency procedures was 41.4%, while perforation in elective surgeries was 30.0%. A statistically significant difference (P < 0.05) was found in between emergency and elective surgeries. There were a very high rate of perforations of gloves among first surgeons 40.6% and scrub nurses 38.8% during elective procedures and among first surgeons (60.14%), and second assistants (53.0%) during emergency surgeries. Only 0.4% of inner gloves were perforated. The left hand, the left index finger and thumb were the most commonly perforated parts of the glove. Glove perforation rate was low among consultant surgeons than residents. Our reported perforation rate is higher than most publications, and this shows that the surgical workforce in Ethiopia is under a clear and present threat. Measures such as double gloving seems to have effectively prevented cutaneous blood exposure and thus should become a routine for all surgical procedures. Manufacturing related defects and faults in glove quality may also be contributing factors.

Immediate detection of endoscopic retrograde cholangiopancreatography-related periampullary perforation: Fluoroscopy or endoscopy?

PubMed Central

Motomura, Yasuaki; Akahoshi, Kazuya; Gibo, Junya; Kanayama, Kenji; Fukuda, Shinichiro; Hamada, Shouhei; Otsuka, Yoshihiro; Kubokawa, Masaru; Kajiyama, Kiyoshi; Nakamura, Kazuhiko

2014-01-01

AIM: To investigate the causes and intraoperative detection of endoscopic retrograde cholangiopancreatography (ERCP)-related perforations to support immediate or early diagnosis. METHODS: Consecutive patients who underwent ERCP procedures at our hospital between January 2008 and June 2013 were retrospectively enrolled in the study (n = 2674). All procedures had been carried out using digital fluoroscopic assistance with the patient under conscious sedation. For patients showing alterations in the gastrointestinal anatomy, a short-type double balloon enteroscope had been applied. Cases of perforation had been identified by the presence of air in or leakage of contrast medium into the retroperitoneal space, or upon endoscopic detection of an abdominal cavity related to the perforated lumen. For patients with ERCP-related perforations, the data on medical history, endoscopic findings, radiologic findings, diagnostic methods, management, and clinical outcomes were used for descriptive analysis. RESULTS: Of the 2674 ERCP procedures performed during the 71-mo study period, only six (0.22%) resulted in perforations (male/female, 2/4; median age: 84 years; age range: 57-97 years). The cases included an endoscope-related duodenal perforation, two periampullary perforations related to endoscopic sphincterotomy, two periampullary perforations related to endoscopic papillary balloon dilation, and a periampullary or bile duct perforation secondary to endoscopic instrument trauma. No cases of guidewire-related perforation occurred. The video endoscope system employed in all procedures was only able to immediately detect the endoscope-related perforation; the other five perforation cases were all detected by subsequent digital fluoroscope applied intraoperatively (at a median post-ERCP intervention time of 15 min). Three out of the six total perforation cases, including the single case of endoscope-related duodenal injury, were surgically treated; the remaining three cases were treated with conservative management, including trans-arterial embolization to control the bleeding in one of the cases. All patients recovered without further incident. CONCLUSION: ERCP-related perforations may be difficult to diagnose by video endoscope and digital fluoroscope detection of retroperitoneal free air or contrast medium leakage can facilitate diagnosis. PMID:25400465

Three-point bending of honeycomb sandwich beams with facesheet perforations

NASA Astrophysics Data System (ADS)

Su, Pengbo; Han, Bin; Zhao, Zhongnan; Zhang, Qiancheng; Lu, Tian Jian

2017-12-01

A novel square honeycomb-cored sandwich beam with perforated bottom facesheet is investigated under three-point bending, both analytically and numerically. Perforated square holes in the bottom facesheet are characterized by the area ratio of the hole to intact facesheet (perforation ratio). While for large-scale engineering applications like the decks of cargo vehicles and transportation ships, the perforations are needed to facilitate the fabrication process (e.g., laser welding) as well as service maintenance, it is demonstrated that these perforations, when properly designed, can also enhance the resistance of the sandwich to bending. For illustration, fair comparisons among competing sandwich designs having different perforation ratios but equal mass is achieved by systematically thickening the core webs. Further, the perforated sandwich beam is designed with a relatively thick facesheet to avoid local indention failure so that it mainly fails in two competing modes: (1) bending failure, i.e., yielding of beam cross-section and buckling of top facesheet caused by bending moment; (2) shear failure, i.e., yielding and buckling of core webs due to shear forcing. The sensitivity of the failure loads to the ratio of core height to beam span is also discussed for varying perforation ratios. As the perforation ratio is increased, the load of shear failure increases due to thickening core webs, while that of bending failure decreases due to the weakening bottom facesheet. Design of a sandwich beam with optimal perforation ratio is realized when the two failure loads are equal, leading to significantly enhanced failure load (up to 60% increase) relative to that of a non-perforated sandwich beam with equal mass.

The Heidelberg Appendicitis Score Predicts Perforated Appendicitis in Children.

PubMed

Boettcher, Michael; Günther, Patrick; Breil, Thomas

2017-10-01

In the future, surgical management of pediatric appendicitis might become limited to nonperforating appendicitis. Thus, it becomes increasingly important to differentiate advanced from simple appendicitis and to predict perforated appendicitis among a group of children with right-sided abdominal pain, which was the aim of this study. An institutionally approved, single-center retrospective analysis of all patients with appendectomy from January 2009 to December 2010 was conducted. All diagnostic aspects were evaluated to identify predictors and differentiators of perforated appendicitis. In 2 years, 157 children suffered from appendicitis. Perforation occurred in 47 (29.9%) of the patients. C-reactive protein (CRP) levels higher than 20 mg/dL ( P = .037) and free abdominal fluid on ultrasonography ( P = .031) are the most important features to differentiate perforated from simple appendicitis. Moreover, all children with perforation had a positive Heidelberg Appendicitis Score (HAS). A negative HAS excludes perforation in all cases (negative predictive value = 100%). Perforated appendicitis can be ruled out by the HAS. In a cohort with right-sided abdominal pain, perforation should be considered in children with high CRP levels and free fluids or abscess formation on ultrasound.

Reliable harvest of a dorsal scapular artery perforator flap by augmenting its perfusion.

PubMed

Kim, So-Young; Lee, Kyeong-Tae; Mun, Goo-Hyun

2016-02-01

Despite confirmation of a reliable perforasome in the dorsal scapular artery in an anatomic study, a true perforator flap has not been recommended in previous clinical studies because of concerns regarding insufficient perfusion in the distal region. In this report, we present two cases of reconstruction for occipital defects caused by tumor extirpation using pedicled dorsal scapular artery perforator flaps without a muscle component. To secure the perfusion of the dorsal scapular artery perforator flap, inclusion of an additional perforator was attempted for perfusion augmentation. The second dorsal scapular artery perforator was harvested in one case. In an additional case, the sixth dorsal intercostal artery perforator with a branch that directly connected with the dorsal scapular artery within the trapezius muscle was additionally harvested. The flaps survived without any perfusion-related complications, including tip necrosis, and no donor site morbidities were observed. We suggest that a perfusion augmented dorsal scapular artery perforator flap by harvesting multiple perforators could be a safe and useful alternative for reconstructive surgery of head and neck defects. © 2014 Wiley Periodicals, Inc.

Instrumental measurement of odour nuisance in city agglomeration using electronic nose

NASA Astrophysics Data System (ADS)

Szulczyński, Bartosz; Dymerski, Tomasz; Gębicki, Jacek; Namieśnik, Jacek

2018-01-01

The paper describes an operation principle of odour nuisance monitoring network in a city agglomeration. Moreover, it presents the results of investigation on ambient air quality with respect to odour obtained during six-month period. The investigation was carried out using a network comprised of six prototypes of electronic nose and Nasal Ranger field olfactometers employed as a reference method. The monitoring network consisted of two measurement stations localized in a vicinity of crude oil processing plant and four stations localized near the main emitters of volatile odorous compounds such as sewage treatment plant, municipal landfill, phosphatic fertilizer production plant. The electronic nose prototype was equipped with a set of six semiconductor sensors by FIGARO Co. and one PID-type sensor. The field olfactometers were utilized for determination of mean concentration of odorants and for calibration of the electronic nose prototypes in order to provide their proper operation. Mean monthly values of odour concentration depended on the site of measurement and on meteorological parameters. They were within 0 - 6.0 ou/m3 range. Performed investigations revealed the possibility of electronic nose instrument application as a tool for monitoring of odour nuisance.

Fabrication of all-inorganic nanocrystal solids through matrix encapsulation of nanocrystal arrays.

PubMed

Kinder, Erich; Moroz, Pavel; Diederich, Geoffrey; Johnson, Alexa; Kirsanova, Maria; Nemchinov, Alexander; O'Connor, Timothy; Roth, Dan; Zamkov, Mikhail

2011-12-21

A general strategy for low-temperature processing of colloidal nanocrystals into all-inorganic films is reported. The present methodology goes beyond the traditional ligand-interlinking scheme and relies on encapsulation of morphologically defined nanocrystal arrays into a matrix of a wide-band gap semiconductor, which preserves optoelectronic properties of individual nanoparticles while rendering the nanocrystal film photoconductive. Fabricated solids exhibit excellent thermal stability, which is attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells. © 2011 American Chemical Society

High-Speed Binary-Output Image Sensor

NASA Technical Reports Server (NTRS)

Fossum, Eric; Panicacci, Roger A.; Kemeny, Sabrina E.; Jones, Peter D.

1996-01-01

Photodetector outputs digitized by circuitry on same integrated-circuit chip. Developmental special-purpose binary-output image sensor designed to capture up to 1,000 images per second, with resolution greater than 10 to the 6th power pixels per image. Lower-resolution but higher-frame-rate prototype of sensor contains 128 x 128 array of photodiodes on complementary metal oxide/semiconductor (CMOS) integrated-circuit chip. In application for which it is being developed, sensor used to examine helicopter oil to determine whether amount of metal and sand in oil sufficient to warrant replacement.

Preliminary performances measured on a CMOS long linear array for space application

NASA Astrophysics Data System (ADS)

Renard, Christophe; Artinian, Armand; Dantes, Didier; Lepage, Gérald; Diels, Wim

2017-11-01

This paper presents the design and the preliminary performances of a CMOS linear array, resulting from collaboration between Alcatel Alenia Space and Cypress Semiconductor BVBA, which takes advantage of emerging potentialities of CMOS technologies. The design of the sensor is presented: it includes 8000 panchromatic pixels with up to 25 rows used in TDI mode, and 4 lines of 2000 pixels for multispectral imaging. Main system requirements and detector tradeoffs are recalled, and the preliminary test results obtained with a first generation prototype are summarized and compared with predicted performances.

Carbon p Electron Ferromagnetism in Silicon Carbide

PubMed Central

Wang, Yutian; Liu, Yu; Wang, Gang; Anwand, Wolfgang; Jenkins, Catherine A.; Arenholz, Elke; Munnik, Frans; Gordan, Ovidiu D.; Salvan, Georgeta; Zahn, Dietrich R. T.; Chen, Xiaolong; Gemming, Sibylle; Helm, Manfred; Zhou, Shengqiang

2015-01-01

Ferromagnetism can occur in wide-band gap semiconductors as well as in carbon-based materials when specific defects are introduced. It is thus desirable to establish a direct relation between the defects and the resulting ferromagnetism. Here, we contribute to revealing the origin of defect-induced ferromagnetism using SiC as a prototypical example. We show that the long-range ferromagnetic coupling can be attributed to the p electrons of the nearest-neighbor carbon atoms around the VSiVC divacancies. Thus, the ferromagnetism is traced down to its microscopic electronic origin. PMID:25758040

Long-Term Characterization of 6H-SiC Transistor Integrated Circuit Technology Operating at 500 C

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Chang, Carl W.; Beheim, Glenn M.; Okojie, Robert S.; Evans, Laura J.; Meredith Roger D.; Ferrier, Terry L.; Krasowski, Michael J.;

Carbon p electron ferromagnetism in silicon carbide

DOE PAGES

Wang, Yutian; Liu, Yu; Wang, Gang; ...

2015-03-11

Ferromagnetism can occur in wide-band gap semiconductors as well as in carbon-based materials when specific defects are introduced. It is thus desirable to establish a direct relation between the defects and the resulting ferromagnetism. Here, we contribute to revealing the origin of defect-induced ferromagnetism using SiC as a prototypical example. We show that the long-range ferromagnetic coupling can be attributed to the p electrons of the nearest-neighbor carbon atoms around the V SiV C divacancies. Thus, the ferromagnetism is traced down to its microscopic electronic origin.

Postoperative Gastric Perforation in a Newborn with Duodenal Atresia.

PubMed

Antabak, Anko; Bogović, Marko; Vuković, Jurica; Grizelj, Ruža; Babić, Vinka Barbarić; Papeš, Dino; Luetić, Tomislav

2016-01-01

Gastric perforation (GP) in neonates is a rare entity with high mortality. Although the etiology is not completely understood, it mostly occurs in premature neonates on assisted ventilation. Combination of duodenal atresia and gastric perforation is very rare. We present a case duodenal atresia who developed gastric perforation after operetion for duodenal atresia. Analysis of the patient medical record and histology report did not reveal the etiology of the perforation.

Delta neutrophil index: A reliable marker to differentiate perforated appendicitis from non-perforated appendicitis in the elderly.

PubMed

Shin, Dong Hyuk; Cho, Young Suk; Kim, Yoon Sung; Ahn, Hee Cheol; Oh, Young Taeck; Park, Sang O; Won, Moo-Ho; Cho, Jun Hwi; Kim, Young Myeong; Seo, Jeong Yeol; Lee, Young Hwan

2018-01-01

Delta neutrophil index (DNI) is a new inflammatory marker and the present study aimed to evaluate the predictive value of the DNI for the presence of a perforation in elderly with acute appendicitis. This retrospective observational study was conducted on 108 consecutive elderly patients (≥65 years old) with acute appendicitis treated over a 24-month period. Sixty-nine of the 108 patients (median, IQR: 72, 67-77 years) were allocated to the perforated appendicitis group (63.9%) and 39 to the non-perforated appendicitis group (36.1%). WBC, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and DNI were significantly higher in the perforated group. In multiple logistic regression analyses, initial DNI was the only independent marker that can significantly predict the presence of perforation in multiple regression [odds ratio 9.38, 95% confidence interval (2.51-35.00), P=.001]. Receiver operator characteristic curve analysis showed that DNI is a good predictor for the presence of appendiceal perforation at an optimal cut-off for DNI being 1.4% (sensitivity 67.7%, specificity 90.0%, AUC 0.807). Clinicians can reliably differentiate acute perforated appendicitis from non-perforated appendicitis by DNI level of 1.4 or more in elderly patients. © 2017 Wiley Periodicals, Inc.

Porcine experimental model for perforator flap raising in reconstructive microsurgery.

PubMed

González-García, José A; Chiesa-Estomba, Carlos M; Álvarez, Leire; Altuna, Xabier; García-Iza, Leire; Thomas, Izaskun; Sistiaga, Jon A; Larruscain, Ekhiñe

2018-07-01

Perforator free flap-based reconstruction of the head and neck is a challenging surgical procedure and needs a steep learning curve. A reproducible mammal large animal model with similarities to human anatomy is relevant for perforator flap raising and microanastomosis. The aim of this study was to assess the feasibility of a swine model for perforator-based free flaps in reconstructive microsurgery. Eleven procedures were performed under general anesthesia in a porcine model, elevating a skin flap vascularized by perforating musculocutaneous branches of the superior epigastric artery to evaluate the relevance of this model for head and neck reconstructive microsurgery. The anterior abdominal skin perforator-based free flap in a swine model irrigated by the superior epigastric artery was elevated in eleven procedures. In six of these procedures, we could perform an arterial and venous microanastomosis to the great vessels located in the base of the neck. The porcine experimental model of superior epigastric artery perforator-based free flap reconstruction offers relevant similarities to the human deep inferior epigastric artery perforator flap. We could demonstrate this model as acceptable for perforator free flap training due to the necessity of perforator and pedicle dissection and transfer to a distant area. Copyright © 2018 Elsevier Inc. All rights reserved.

Glove perforation in hip and knee arthroplasty.

PubMed

Demircay, Emre; Unay, Koray; Bilgili, Mustafa G; Alataca, Gulum

2010-11-01

The transmission of blood-borne pathogens during surgery is a major concern. Surgical gloves are the primary barrier between the surgeon and the patient. Surgical procedures that need manual handling of bony surfaces or sharp instruments have the highest risk of glove perforations. The frequencies and the sites of surgical glove perforations in arthroplasty procedures were assessed. We assessed the surgical glove perforations in total hip and knee arthroplasty procedures. Double standard latex gloves were used. A total of 983 outer and 511 inner gloves were tested. The gloves of all the surgical team members were tested for perforations during the first and second hours of surgery. There were 18.4% outer and 8.4% inner glove perforations. The most frequent site of perforation was the second digit of the nondominant hand (25.5%). We found that hip and knee arthroplasty had significantly more glove perforation risk for the surgeon in the first half of the operation rather than the second half, and 57.8% of the perforations were at the index finger and the thumb. Arthroplasty procedures still have high glove perforation rates despite the use of double gloving with frequent changes. Extra augmentation of the gloves in selected areas of the hand, in addition to double gloving, may be safer and more cost-effective than double gloving alone.

Intraabdominal contamination after gallbladder perforation during laparoscopic cholecystectomy and its complications.

PubMed

Kimura, T; Goto, H; Takeuchi, Y; Yoshida, M; Kobayashi, T; Sakuramachi, S; Harada, Y

1996-09-01

Gallbladder perforation often occurs during laparoscopic cholecystectomy. The frequency and causes of gallbladder perforation as well as the relevant clinical background factors were investigated in 110 patients undergoing laparoscopic cholecystectomy. We also evaluated intraperitoneal contamination by bacteria and gallstones at the time of gallbladder perforation and investigated whether perforation caused early or late postoperative complications. Intraoperative gallbladder perforation occurred in 29 of the 110 patients (26.3%). It was caused by injury with an electric knife during dissection of the gallbladder bed, injury during gallbladder retraction with grasping forceps, injury during gallbladder extraction from the abdomen, and slippage of cystic duct clips (potentially causing bile and stone spillage). Perforation was more frequent in patients with positive bile cultures and in those with pigment stones (p < 0.02), but not in patients with cholecystitis or cystic duct obstruction. The peritoneal cavity was contaminated by bacteria in 11/29 patients (37.9%) and by spilled stones in 3/29 patients (10.3%). There was no difference in the incidence of postoperative complications between the patients with and without perforation either in the early postoperative period or during follow-up for 24-42 months. Only one patient developed abdominal pain and fever in the early postoperative period, and they were probably related to perforation. Although gallbladder perforation is sometimes unavoidable during laparoscopic cholecystectomy, the risk of severe complications appears to be minimized by early closure of perforation, retrieval of as many of the spilled stones as possible, and intraperitoneal lavage.

Use of inferior gluteal artery and posterior thigh perforators in management of ischial pressure sores with limited donor sites for flap coverage.

PubMed

Unal, Cigdem; Ozdemir, Jale; Yirmibesoglu, Oktay; Yucel, Ergin; Agir, Hakan

2012-07-01

Reconstructive surgery for ischial pressure sore defects presents a challenge because of high rates of recurrence. The aim of this study was to describe the use of inferior gluteal artery (IGA) and posterior thigh perforators in management of ischial pressure sores with limited donor sites. Between September 2005 and 2009, 11 patients (9 male, 2 female) with ischial sores were operated by using IGA and posterior thigh perforator flaps. The data of patients included age, sex, cause of paraplegia, flap size, perforator of flap, previous surgeries, recurrences, complications, and postoperative follow-up. Nine IGA and 5 posterior thigh perforator flaps were used. Six patients presented with recurrent lesions, 5 patients were operated for sacral and contralateral ischial pressure sores previously. In 2 patients, IGA and posterior thigh perforator flaps were used in combination. Patients were followed for an average of 34.3 months. In 2 recurrent cases, readvancement of IGA perforator flap and gluteus maximus myocutaneous flap were treatment of choice. Treatment of patients with recurrent lesions or multiple pressure sores is challenging because of limited available flap donor sites. In this study, posterior thigh perforator flaps were preferred in patients in whom the previous donor site was the gluteal region. IGA perforator flaps were the treatment of choice in patients for whom posterior thigh region was previously used. Alternately, preserved perforators of previous conventional myocutaneous flaps enabled us to use these perforators in recurrences.

Comparison of the Multidetector-row Computed Tomographic Angiography Axial and Coronal Planes' Usefulness for Detecting Thoracodorsal Artery Perforators

PubMed Central

Kim, Jong Gyu

2012-01-01

Background During the planning of a thoracodorsal artery perforator (TDAP) free flap, preoperative multidetector-row computed tomographic (MDCT) angiography is valuable for predicting the locations of perforators. However, CT-based perforator mapping of the thoracodorsal artery is not easy because of its small diameter. Thus, we evaluated 1-mm-thick MDCT images in multiple planes to search for reliable perforators accurately. Methods Between July 2010 and October 2011, 19 consecutive patients (13 males, 6 females) who underwent MDCT prior to TDAP free flap operations were enrolled in this study. Patients ranged in age from 10 to 75 years (mean, 39.3 years). MDCT images were acquired at a thickness of 1 mm in the axial, coronal, and sagittal planes. Results The thoracodorsal artery perforators were detected in all 19 cases. The reliable perforators originating from the descending branch were found in 14 cases, of which 6 had transverse branches. The former were well identified in the coronal view, and the latter in the axial view. The location of the most reliable perforators on MDCT images corresponded well with the surgical findings. Conclusions Though MDCT has been widely used in performing the abdominal perforator free flap for detecting reliable perforating vessels, it is not popular in the TDAP free flap. The results of this study suggest that multiple planes of MDCT may increase the probability of detecting the most reliable perforators, along with decreasing the probability of missing available vessels. PMID:22872839

Risk factors associated with conversion of laparoscopic simple closure in perforated duodenal ulcer.

PubMed

Kim, Ji-Hyun; Chin, Hyung-Min; Bae, You-Jin; Jun, Kyong-Hwa

2015-03-01

Precise patient selection criteria are necessary to guide the surgeon in selecting laparoscopic repair for patients with perforated peptic ulcers. The aims of this study are to report surgical outcomes after surgery for perforated duodenal ulcers and identify risk factors for predicting failure of laparoscopic simple closure for perforated duodenal ulcer. In total, 77 patients who underwent laparoscopic simple closure for perforated duodenal ulcers from January 2007 to September 2013 were retrospectively analyzed. Patients were divided into totally laparoscopic and conversion groups. The characteristics of patients, intraoperative findings, postoperative complications, conversion rates and suture leakage rates of each group were investigated. Laparoscopic repair was completed in 69 (89.6%) of 77 patients, while 8 (10.4%) underwent conversion to open repair. Patients in the conversion group had longer perforation time, larger perforation size, more suture leakage, longer hospital stay, and higher 30-day mortality rate than those in the totally laparoscopic group. The size of perforation was the only risk factor for conversion in multivariable analysis. Patients with an ulcer perforation size of ≥9 mm or with perforation duration of ≥12.5 h had a significantly increased risk for conversion and suture leakage. Ulcer size of ≥9 mm is a significant risk factor for predicting conversion in laparoscopic simple closure. Suture leakage is associated with ulcer size (9 mm) and duration of perforation (12.5 h). Copyright © 2015 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Dye sensitized solar cell (DSSC) with natural dyes extracted from Jatropha leaves and purple Chrysanthemum flowers as sensitizer

NASA Astrophysics Data System (ADS)

Tahir, Dahlang; Satriani, Wilda; Gareso, P. L.; Abdullah, B.

2018-03-01

DSSC (Dye-Sensitized Solar Cell) prototype has been investigated using Jatropha leaves and purple Chrysanthemum flowers as natural dyes. DSSC consists of working electrode and counter electrode. A working electrode composed of semiconductor nanoparticles TiO2 that has been coated with dye molecules. Dye molecules serve as light photon catchers, while semiconductor nanoparticles TiO2 function to absorb and forward photons into electrons. In the electrode counter given catalyst carbon, serves to accelerate the reaction kinetics of triiodide reduction process on transparent conductive oxide (TCO). DSSC using TiO2 as a semiconductor material and natural dyes as sensitizer from Jatropha leaves and purple Chrysanthemum flowers are successful produced. The physical properties of the working electrode have been determined by using XRD and the chemical properties of the TiO2 powder and dye powder using FTIR and dye solution using UV-Vis. The resulted fabrications are also examined its I-V characteristics. The best performance is generated by mixed dye 1.91 x 10-3 % compared than those DSSC for dye extracted from Jatropha leaves or purple Chrysanthemum. The characterization results show that the higher of the absorption wavelength of the DSSC efficiency is high.

Designing solution-processable air-stable liquid crystalline crosslinkable semiconductors.

PubMed

McCulloch, Iain; Bailey, Clare; Genevicius, Kristijonas; Heeney, Martin; Shkunov, Maxim; Sparrowe, David; Tierney, Steven; Zhang, Weimin; Baldwin, Rodney; Kreouzis, Theo; Andreasen, Jens W; Breiby, Dag W; Nielsen, Martin M

2006-10-15

Organic electronics technology, in which at least the semiconducting component of the integrated circuit is an organic material, offers the potential for fabrication of electronic products by low-cost printing technologies, such as ink jet, gravure offset lithography and flexography. The products will typically be of lower performance than those using the present state of the art single crystal or polysilicon transistors, but comparable to amorphous silicon. A range of prototypes are under development, including rollable electrophoretic displays, active matrix liquid crystal (LC) displays, flexible organic light emitting diode displays, low frequency radio frequency identification tag and other low performance electronics. Organic semiconductors that offer both electrical performance and stability with respect to storage and operation under ambient conditions are required. This work describes the development of reactive mesogen semiconductors, which form large crosslinked LC domains on polymerization within mesophases. These crosslinked domains offer mechanical stability and are inert to solvent exposure in further processing steps. Reactive mesogens containing conjugated aromatic cores, designed to facilitate charge transport and provide good oxidative stability, were prepared and their liquid crystalline properties evaluated. The organization and alignment of the mesogens, both before and after crosslinking, were probed by grazing incidence wide-angle X-ray scattering of thin films. Both time-of-flight and field effect transistor devices were prepared and their electrical characterization reported.

Excitons and Davydov splitting in sexithiophene from first-principles many-body Green's function theory

NASA Astrophysics Data System (ADS)

Leng, Xia; Yin, Huabing; Liang, Dongmei; Ma, Yuchen

2015-09-01

Organic semiconductors have promising and broad applications in optoelectronics. Understanding their electronic excited states is important to help us control their spectroscopic properties and performance of devices. There have been a large amount of experimental investigations on spectroscopies of organic semiconductors, but theoretical calculation from first principles on this respect is still limited. Here, we use density functional theory (DFT) and many-body Green's function theory, which includes the GW method and Bethe-Salpeter equation, to study the electronic excited-state properties and spectroscopies of one prototypical organic semiconductor, sexithiophene. The exciton energies of sexithiophene in both the gas and bulk crystalline phases are very sensitive to the exchange-correlation functionals used in DFT for ground-state structure relaxation. We investigated the influence of dynamical screening in the electron-hole interaction on exciton energies, which is found to be very pronounced for triplet excitons and has to be taken into account in first principles calculations. In the sexithiophene single crystal, the energy of the lowest triplet exciton is close to half the energy of the lowest singlet one. While lower-energy singlet and triplet excitons are intramolecular Frenkel excitons, higher-energy excitons are of intermolecular charge-transfer type. The calculated optical absorption spectra and Davydov splitting are in good agreement with experiments.

[Pedicle flap of nasal septum-basis nasi and temporal muscucofascial flap to repair nasoseptal perforation].

PubMed

Yin, Xinghong; Hu, Wei; Zhang, Xinhai; Sun, Min

2014-10-01

To explore curative effect with pedicle flap of nasal septum-basis nasi and temporal muscucofascial flap to repair nasal septal perforation. Dissecting mucoperichondrium and mucoperioseptum around the perforation and taking dowm and out xia-ward to the floor of nasal cavity to make a inferior extremity pedicle flap. Then,the flap was tumbled and sutured onto raw surface of contralateral side through perforation. Reapplicating autoallergic temporal musculofascial flap to repair another side perforation. Repairing perforation Sin twelve cases were sucessfully healed in endoscope. The pedicle flap of nasal septum-basis nasi and temporal muscucofascial flap is easy to acquire and no rejection. The flap has good blood supplying, high survival rate and provides adequate transplantating materail to repair comparatively large perforation.

Postoperative Gastric Perforation in a Newborn with Duodenal Atresia

PubMed Central

Antabak, Anko; Bogović, Marko; Vuković, Jurica; Grizelj, Ruža; Babić, Vinka Barbarić; Papeš, Dino; Luetić, Tomislav

2016-01-01

Gastric perforation (GP) in neonates is a rare entity with high mortality. Although the etiology is not completely understood, it mostly occurs in premature neonates on assisted ventilation. Combination of duodenal atresia and gastric perforation is very rare. We present a case duodenal atresia who developed gastric perforation after operetion for duodenal atresia. Analysis of the patient medical record and histology report did not reveal the etiology of the perforation. PMID:27896170

Use of Continuous Integration Tools for Application Performance Monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vergara Larrea, Veronica G; Joubert, Wayne; Fuson, Christopher B

High performance computing systems are becom- ing increasingly complex, both in node architecture and in the multiple layers of software stack required to compile and run applications. As a consequence, the likelihood is increasing for application performance regressions to occur as a result of routine upgrades of system software components which interact in complex ways. The purpose of this study is to evaluate the effectiveness of continuous integration tools for application performance monitoring on HPC systems. In addition, this paper also describes a prototype system for application perfor- mance monitoring based on Jenkins, a Java-based continuous integration tool. The monitoringmore » system described leverages several features in Jenkins to track application performance results over time. Preliminary results and lessons learned from monitoring applications on Cray systems at the Oak Ridge Leadership Computing Facility are presented.« less

Tensor fascia lata flap versus tensor fascia lata perforator-based island flap for the coverage of extensive trochanteric pressure sores.

PubMed

Kim, Youn Hwan; Kim, Sang Wha; Kim, Jeong Tae; Kim, Chang Yeon

2013-06-01

Tensor fascia lata (TFL) musculocutaneous flaps often require a donor site graft when harvesting a large flap. However, a major drawback is that it also sacrifices the muscle. To overcome this disadvantage, we designed a TFL perforator-based island flap that was harvested from a site near the defect and involved transposition within 90 degrees without full isolation of the pedicles. We performed procedures on 17 musculocutaneous flaps and 23 perforator-based island flaps, and compared the outcomes of these surgeries. The overall complication rate was 27.5% (11 regions). There were 7 complications related to the musculocutaneous flaps and 4 complications related to the perforator flaps. Although there were no statistical differences between those groups, lower complication rates were associated with procedures involving perforator flaps. The TFL perforator procedure is a simple and fast operation that avoids sacrificing muscle. This decreases complication rates compared to true perforator flap techniques that require dissection around the perforator or pedicle.

[Reconstruction of ankle and foot with combination of free perforator flaps and skin graft].

PubMed

Yin, Lu; Gong, Ketong; Yin, Zhonggang; Zhang, Bo; Xu, Jianhua

2017-03-01

To evaluate the clinical outcomes of free perforator flaps combined with skin graft for reconstruction of ankle and foot soft tissue defects. Between June 2014 and October 2015, 20 cases of ankle and foot soft tissue defects were treated. There were 16 males and 4 females, aged from 19 to 61 years (mean, 43.3 years). Injury was caused by traffic accident in 7 cases, by crashing in 9 cases, and machine twist in 4 cases. The locations were the ankle in 6 cases, the heel in 3 cases, the dorsum pedis in 4 cases, and the plantar forefoot in 7 cases of avulsion injury after toes amputation. The size of wound ranged from 15 cm×10 cm to 27 cm×18 cm. The time from injury to treatment was from 11 to 52 days (mean, 27 days). The anterolateral thigh perforator flap was used in 11 cases, thoracodorsal antery perforator flap in 3 cases, medial sural artery perforator flap in 4 cases, deep inferior epigastric perforator flap in 1 case, and anteromedial thigh perforator flap in 1 case, including 5 chimeric perforator flaps, 5 polyfoliate perforator flaps, 3 flow-through perforator flaps, and 3 conjoined perforator flaps. The size of the perforator flap ranged from 10.0 cm×6.5 cm to 36.0 cm×8.0 cm, the size of skin graft from 5 cm×3 cm to 18 cm×12 cm. Venous crisis occurred in 2 flaps which survived after symptomatic treatment; 18 flaps survived successfully and skin grafting healed well. The follow-up time ranged 4-18 months (mean, 8.3 months). The flaps had good appearance, texture and color, without infection. The patients could walk normally and do daily activities. Only linear scars were observed at the donor sites. Free perforator flap can be used to reconstruct defects in the ankle and foot, especially in the weight-bearing area of the plantar forefoot. A combination of free perforator flap and skin graft is ideal in reconstruction of great soft tissue defects in the ankle and foot.

Skin-Inspired Hydrogel-Elastomer Composite with Application in a Moisture Permeable Prosthetic Limb Liner

NASA Astrophysics Data System (ADS)

Ruiz, Esteban

Recent advances in fields such as 3D printing, and biomaterials, have enabled the development of a moisture permeable prosthetic liner. This project demonstrates the feasibility of the invention by addressing the three primary areas of risk including the mechanical strength, the permeability, and the ability to manufacture. The key enabling technology which allows the liner to operate is the skin inspired hydrogel elastomer composite. The skin inspiration is reflected in the molecular arrangement of the double network of polymers which mimics collagen-elastin toughening in the natural epidermis. A custom formulation for a novel tough double network nanocomposite reinforced hydrogel was developed to improve manufacturability of the liner. The liner features this double network nanocomposite reinforced hydrogel as a permeable membrane which is reinforced on either side by perforated silicone layers manufactured by 3d printing assisted casting. Uniaxial compression tests were conducted on the individual hydrogels, as well as a representative sample of off the shelf prosthetic liners for comparison. Permeability testing was also done on the same set of materials and compared to literature values for traditional hydrogels. This work led to the manufacture of three generations of liner prototypes, with the second and third liner prototype being tested with human participants.

Glove Perforations During Interventional Radiological Procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leena, R. V., E-mail: leenarv_76@yahoo.co.uk; Shyamkumar, N. K.

2010-04-15

Intact surgical gloves are essential to avoid contact with blood and other body fluids. The objective of this study was to estimate the incidence of glove perforations during interventional radiological procedures. In this study, a total of 758 gloves used in 94 interventional radiological procedures were examined for perforations. Eleven perforations were encountered, only one of which was of occult type. No significant difference in the frequency of glove perforation was found between the categories with varying time duration.

Novel pulsed switched power supply for a fast field cycling NMR spectrometer.

PubMed

Sousa, D M; Fernandes, P A L; Marques, G D; Ribeiro, A C; Sebastião, P J

2004-01-01

In this paper, we outline the operating principles of a pulsed switched power supply for a fast field-cycling nuclear magnetic resonance spectrometer. The power supply uses a variant of a four-quadrant chopper with a duty cycle that defines the average output current. With this topology only two semiconductors are necessary to drive hundreds of amperes with an output power of several kilowatts. The output current ripple has a well-defined shape that can be reduced to acceptable values by a careful design of the semiconductors' controlling circuits and drivers. A power supply prototype was tested with a home build air-core magnet operating with fields between 0 and 0.21 T. The system is computer controlled using pulse generator and data acquisition PC cards, and specific user-friendly home-developed software. A comparative proton relaxometry study in two well-known liquid crystal compounds 5CB and MBBA was performed to check the reproducibility of the T1 measurements.

Enhanced photocatalytic CO₂-reduction activity of electrospun mesoporous TiO₂ nanofibers by solvothermal treatment.

PubMed

Fu, Junwei; Cao, Shaowen; Yu, Jiaguo; Low, Jingxiang; Lei, Yongpeng

2014-06-28

Photocatalytic reduction of CO2 into renewable hydrocarbon fuels using semiconductor photocatalysts is considered as a potential solution to the energy deficiency and greenhouse effect. In this work, mesoporous TiO2 nanofibers with high specific surface areas and abundant surface hydroxyl groups are prepared using an electrospinning strategy combined with a subsequent calcination process, followed by a solvothermal treatment. The solvothermally treated mesoporous TiO2 nanofibers exhibit excellent photocatalytic performance on CO2 reduction into hydrocarbon fuels. The significantly improved photocatalytic activity can be attributed to the enhanced CO2 adsorption capacity and the improved charge separation after solvothermal treatment. The highest activity is achieved for the sample with a 2-h solvothermal treatment, showing 6- and 25-fold higher CH4 production rate than those of TiO2 nanofibers without solvothermal treatment and P25, respectively. This work may also provide a prototype for studying the effect of solvothermal treatment on the structure and photocatalytic activity of semiconductor photocatalysts.

Imaging exciton–polariton transport in MoSe2 waveguides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, F.; Luan, Y.; Scott, M. E.

The exciton polariton (EP), a half-light and half-matter quasiparticle, is potentially an important element for future photonic and quantum technologies1-4. It provides both strong light-matter interactions and long-distance propagation that is necessary for applications associated with energy or information transfer. Recently, strongly-coupled cavity EPs at room temperature have been demonstrated in van der Waals (vdW) materials due to their strongly-bound excitons5-9. Here we report a nano-optical imaging study of waveguide EPs in MoSe2, a prototypical vdW semiconductor. The measured propagation length of the EPs is sensitive to the excitation photon energy and reaches over 12 μm. The polariton wavelength canmore » be conveniently altered from 600 nm down to 300 nm by controlling the waveguide thickness. Furthermore, we found an intriguing back-bending polariton dispersion close to the exciton resonance. The observed EPs in vdW semiconductors could be useful in future nanophotonic circuits operating in the near-infrared to visible spectral regions.« less

Imaging exciton–polariton transport in MoSe2 waveguides

DOE PAGES

Hu, F.; Luan, Y.; Scott, M. E.; ...

2017-05-08

The exciton polariton (EP), a half-light and half-matter quasiparticle, is potentially an important element for future photonic and quantum technologies1-4. It provides both strong light-matter interactions and long-distance propagation that is necessary for applications associated with energy or information transfer. Recently, strongly-coupled cavity EPs at room temperature have been demonstrated in van der Waals (vdW) materials due to their strongly-bound excitons5-9. Here we report a nano-optical imaging study of waveguide EPs in MoSe2, a prototypical vdW semiconductor. The measured propagation length of the EPs is sensitive to the excitation photon energy and reaches over 12 μm. The polariton wavelength canmore » be conveniently altered from 600 nm down to 300 nm by controlling the waveguide thickness. Furthermore, we found an intriguing back-bending polariton dispersion close to the exciton resonance. The observed EPs in vdW semiconductors could be useful in future nanophotonic circuits operating in the near-infrared to visible spectral regions.« less

Stoichiometric and Oxygen-Deficient VO2 as Versatile Hole Injection Electrode for Organic Semiconductors.

PubMed

Fu, Keke; Wang, Rongbin; Katase, Takayoshi; Ohta, Hiromichi; Koch, Norbert; Duhm, Steffen

2018-03-28

Using photoemission spectroscopy, we show that the surface electronic structure of VO 2 is determined by the temperature-dependent metal-insulator phase transition and the density of oxygen vacancies, which depends on the temperature and ultrahigh vacuum (UHV) conditions. The atomically clean and stoichiometric VO 2 surface is insulating at room temperature and features an ultrahigh work function of up to 6.7 eV. Heating in UHV just above the phase transition temperature induces the expected metallic phase, which goes in hand with the formation of oxygen defects (up to 6% in this study), but a high work function >6 eV is maintained. To demonstrate the suitability of VO 2 as hole injection contact for organic semiconductors, we investigated the energy-level alignment with the prototypical organic hole transport material N, N'-di(1-naphthyl)- N, N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB). Evidence for strong Fermi-level pinning and the associated energy-level bending in NPB is found, rendering an Ohmic contact for holes.

Mixing-Induced Anisotropic Correlations in Molecular Crystalline Systems: Rationalizing the Behavior of Organic Semiconductor Blends

NASA Astrophysics Data System (ADS)

Broch, Katharina; Aufderheide, Antje; Novak, Jiri; Hinderhofer, Alexander; Gerlach, Alexander; Banerjee, Rupak; Schreiber, Frank

2013-03-01

Binary mixtures of organic semiconductors (OSCs) have recently become an important field of research, as they find applications in opto-electronic devices. In these systems, the mixing (intermixing vs. phase separation) and ordering behavior is crucial, since it affects the optical and electronic properties. We present a comprehensive study of binary mixtures of the three prototypical OSCs pentacene (PEN), perfluoropentacene (PFP) and diindenoperlyene (DIP) in all possible combinations. Using X-ray reflectivity and grazing incidence X-ray diffraction we investigate the stuctural properties of the mixed films as well as their impact on the optical spectra obtained by spectroscopic ellipsometry. For PEN:DIP we find an anisotropic ordering behavior, comparable to that observed in some liquid crystals, which is fundamentally new for OSCs. The influence of sterical compatibility and the strength of the intermolecular interactions on the mixing and ordering behavior in the different blends will be discussed by extending a conventional mean-field model. Finally, we discuss general rules for the targeted preparation of blends of OSCs.

Note: A disposable x-ray camera based on mass produced complementary metal-oxide-semiconductor sensors and single-board computers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoidn, Oliver R.; Seidler, Gerald T., E-mail: seidler@uw.edu

We have integrated mass-produced commercial complementary metal-oxide-semiconductor (CMOS) image sensors and off-the-shelf single-board computers into an x-ray camera platform optimized for acquisition of x-ray spectra and radiographs at energies of 2–6 keV. The CMOS sensor and single-board computer are complemented by custom mounting and interface hardware that can be easily acquired from rapid prototyping services. For single-pixel detection events, i.e., events where the deposited energy from one photon is substantially localized in a single pixel, we establish ∼20% quantum efficiency at 2.6 keV with ∼190 eV resolution and a 100 kHz maximum detection rate. The detector platform’s useful intrinsic energymore » resolution, 5-μm pixel size, ease of use, and obvious potential for parallelization make it a promising candidate for many applications at synchrotron facilities, in laser-heating plasma physics studies, and in laboratory-based x-ray spectrometry.« less

Semiconductor activated terahertz metamaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Hou-Tong

Metamaterials have been developed as a new class of artificial effective media realizing many exotic phenomena and unique properties not normally found in nature. Metamaterials enable functionality through structure design, facilitating applications by addressing the severe material issues in the terahertz frequency range. Consequently, prototype functional terahertz devices have been demonstrated, including filters, antireflection coatings, perfect absorbers, polarization converters, and arbitrary wavefront shaping devices. Further integration of functional materials into metamaterial structures have enabled actively and dynamically switchable and frequency tunable terahertz metamaterials through the application of external stimuli. The enhanced light-matter interactions in active terahertz metamaterials may result inmore » unprecedented control and manipulation of terahertz radiation, forming the foundation of many terahertz applications. In this paper, we review the progress during the past few years in this rapidly growing research field. We particularly focus on the design principles and realization of functionalities using single-layer and few-layer terahertz planar metamaterials, and active terahertz metamaterials through the integration of semiconductors to achieve switchable and frequency-tunable response.« less

Semiconductor activated terahertz metamaterials

DOE PAGES

Chen, Hou-Tong

2014-08-01

Metamaterials have been developed as a new class of artificial effective media realizing many exotic phenomena and unique properties not normally found in nature. Metamaterials enable functionality through structure design, facilitating applications by addressing the severe material issues in the terahertz frequency range. Consequently, prototype functional terahertz devices have been demonstrated, including filters, antireflection coatings, perfect absorbers, polarization converters, and arbitrary wavefront shaping devices. Further integration of functional materials into metamaterial structures have enabled actively and dynamically switchable and frequency tunable terahertz metamaterials through the application of external stimuli. The enhanced light-matter interactions in active terahertz metamaterials may result inmore » unprecedented control and manipulation of terahertz radiation, forming the foundation of many terahertz applications. In this paper, we review the progress during the past few years in this rapidly growing research field. We particularly focus on the design principles and realization of functionalities using single-layer and few-layer terahertz planar metamaterials, and active terahertz metamaterials through the integration of semiconductors to achieve switchable and frequency-tunable response.« less

Spontaneous acalculous gallbladder perforation in a man secondary to chemotherapy and radiation: A rare case report.

PubMed

Zhang, Jungang; Shen, Guoliang; Shi, Ying; Zhang, Chengwu; Hong, Defei; Jin, Li; Yang, Hongguo; Sun, Wei; Cai, Hanhui; Hu, Zhiming; Wu, Weiding

2018-05-01

Gallbladder perforation is a serious clinical condition and associated with high morbidity and mortality. A definitive diagnosis is contentious before surgery. We herein report a case of perforation of the gallbladder neck secondary to chemotherapy and radiation for nasopharyngeal carcinoma patient. Gallbladder perforation secondary to chemotherapy and radiation. To decrease the mortality associated with gallbladder perforation, Laparoscopic cholecystectomy and peritoneal lavage were performed followed for gallbladder perforation patient because of chemotherapy and radiation. The patient recovered fully without serious complication and discharged on the 10th postoperative day. A pathological examination of the resected gallbladder revealed cholecystitis in the thinning of the neck. Early diagnosis and surgical intervention of gallbladder perforation in relation to asopharyngeal carcinoma chemotherapy and radiation are of prime importance. The laparoscopic procedure is safe and feasible in the selected patients.

[Liver Abscess Secondary to Perforation after Duodenal Endoscopic Resection].

PubMed

Choi, Seung Ho; Kim, Su Jin; Kang, Dae Hwan; Kim, Hyung Wook; Choi, Cheol Woong; Kim, Tae Un; Lee, Jeong Seok; Ko, Ji Hwan

2018-05-25

Duodenal perforation is a complication of endoscopic mucosal resection. Liver abscess secondary to iatrogenic perforation is extremely rare. A 43-year-old female visited the hospital to remove a sub-epithelial tumor on the duodenal bulb. After endoscopic mucosal resection with band ligation, duodenal perforation occurred. Endoscopic closure was performed successfully using a clipping device to manage duodenal perforation. After 4 weeks, the patient visited our outpatient clinic due to abdominal pain and fever. Abdominal computed tomography showed liver abscess that involved segment three. Liver abscess was resolved with a 10-week antibiotic treatment. To the best of our knowledge, no case of liver abscess secondary to duodenal perforation by endoscopic resection was reported to date in Korea. Here, we report a case of liver abscess caused by a duodenal perforation after endoscopic mucosal resection.

[Morphological reasoning of the resected tissue volume by the perforated ulcer of the duodenum].

PubMed

Vachev, A N; Kozlov, A A; Sukhachev, P A; Dergal', S V; Larina, T V

2011-01-01

102 tissue samples, resected during treatment of the perforated duodenal ulcers. The most pronounced fibroplastic and acute inflammatory tissue changes were registered in the immediate perforation zone and 0,5 sm above. At a distance of 1,0 sm these changes become less evident. Therefore, in patients with the perforated duodenal ulcer and palpable surrounding infiltrate less than 3,0 sm in diameter, the resection line should be no shorter than 1,0 sm away from the perforation.

Iatrogenic Aortic Valve Perforation after Ventricular Septal Defect Repair

PubMed Central

Ren, Chonglei; Wang, Mingyan; Wang, Yao; Gao, Changqing

2017-01-01

Iatrogenic aortic valve (AV) perforation during non-aortic cardiac operations is a rare complication. The suture-related inadvertent injury to an AV leaflet can produce leaflet perforation with aortic regurgitation after ventricular septal defect repair (VSDR). We report three consecutive patients who had iatrogenic aortic leaflet perforation during VSDR in other hospitals and referred to our hospital for reoperation. In all three cases, the perforated AV leaflets were preserved and repaired by autologous pericardial patch or direct local closure. PMID:29057770

Low-energy plasma-cathode electron gun with a perforated emission electrode

NASA Astrophysics Data System (ADS)

Burdovitsin, Victor; Kazakov, Andrey; Medovnik, Alexander; Oks, Efim; Tyunkov, Andrey

2017-11-01

We describe research of influence of the geometric parameters of perforated electrode on emission parameters of a plasma cathode electron gun generating continuous electron beams at gas pressure 5-6 Pa. It is shown, that the emission current increases with increasing the hole diameters and decreasing the thickness of the perforated emission electrode. Plasma-cathode gun with perforated electron can provide electron extraction with an efficiency of up to 72 %. It is shown, that the current-voltage characteristic of the electron gun with a perforated emission electrode differs from that of similar guns with fine mesh grid electrode. The plasma-cathode electron gun with perforated emission electrode is used for electron beam welding and sintering.

Optimal conditions for tissue perforation using high intensity focused ultrasound

NASA Astrophysics Data System (ADS)

Mochizuki, Takashi; Kihara, Taizo; Ogawa, Kouji; Tanabe, Ryoko; Yosizawa, Shin; Umemura, Shin-ichiro; Kakimoto, Takashi; Yamashita, Hiromasa; Chiba, Toshio

2012-10-01

To perforate tissue lying deep part in body, a large size transducer was assembled by combining four spherical-shaped transducers, and the optimal conditions for tissue perforation have studied using ventricle muscle of chicken as a target. The ex vivo experiments showed that ventricle muscle was successfully perforated both when it was exposed to High Intensity Focused Ultrasound (HIFU) directly and when it was exposed to HIFU through atrial muscle layer. Moreover, it was shown that calculated acoustic power distributions are well similar to the perforation patterns, and that the acoustic energy distributes very complexly near the focus. Lastly, perforation on the living rabbit bladder wall was demonstrated as a preliminary in vivo experiment.

A case report of esophageal perforation: Complication of nasogastric tube placement

PubMed Central

Isik, Arda; Firat, Deniz; Peker, Kemal; Sayar, Ilyas; Idiz, Oguz; Soytürk, Mehmet

2014-01-01

Patient: Male, 70 Final Diagnosis: Esophageal perforation Symptoms: Abdominal pain • nausea • vomiting Medication: — Clinical Procedure: — Specialty: Surgery Objective: Unusual clinical course Background: Esophageal perforation is a well-defined and severe clinical condition. There are several etiologies of esophagus perforation. Case Report: We report the case of a 70-year-old Caucasian man who underwent an emergency cholecystectomy due to acute cholecystitis. Two days after surgery, his condition deteriorated. Thorax computerized tomography revealed an esophageal perforation. Conclusions: Esophageal perforation due to nasogastric application is relatively rare but the consequences are potentially serious. The anatomy of the upper gastrointestinal system should be understood by all healthcare professionals involved in the treatment. PMID:24803977

Design and exploration of semiconductors from first principles: A review of recent advances

NASA Astrophysics Data System (ADS)

Oba, Fumiyasu; Kumagai, Yu

2018-06-01

Recent first-principles approaches to semiconductors are reviewed, with an emphasis on theoretical insight into emerging materials and in silico exploration of as-yet-unreported materials. As relevant theory and methodologies have developed, along with computer performance, it is now feasible to predict a variety of material properties ab initio at the practical level of accuracy required for detailed understanding and elaborate design of semiconductors; these material properties include (i) fundamental bulk properties such as band gaps, effective masses, dielectric constants, and optical absorption coefficients; (ii) the properties of point defects, including native defects, residual impurities, and dopants, such as donor, acceptor, and deep-trap levels, and formation energies, which determine the carrier type and density; and (iii) absolute and relative band positions, including ionization potentials and electron affinities at semiconductor surfaces, band offsets at heterointerfaces between dissimilar semiconductors, and Schottky barrier heights at metal–semiconductor interfaces, which are often discussed systematically using band alignment or lineup diagrams. These predictions from first principles have made it possible to elucidate the characteristics of semiconductors used in industry, including group III–V compounds such as GaN, GaP, and GaAs and their alloys with related Al and In compounds; amorphous oxides, represented by In–Ga–Zn–O transparent conductive oxides (TCOs), represented by In2O3, SnO2, and ZnO; and photovoltaic absorber and buffer layer materials such as CdTe and CdS among group II–VI compounds and chalcopyrite CuInSe2, CuGaSe2, and CuIn1‑ x Ga x Se2 (CIGS) alloys, in addition to the prototypical elemental semiconductors Si and Ge. Semiconductors attracting renewed or emerging interest have also been investigated, for instance, divalent tin compounds, including SnO and SnS; wurtzite-derived ternary compounds such as ZnSnN2 and CuGaO2; perovskite oxides such as SrTiO3 and BaSnO3; and organic–inorganic hybrid perovskites, represented by CH3NH3PbI3. Moreover, the deployment of first-principles calculations allows us to predict the crystal structure, stability, and properties of as-yet-unreported materials. Promising materials have been explored via high-throughput screening within either publicly available computational databases or unexplored composition and structure space. Reported examples include the identification of nitride semiconductors, TCOs, solar cell photoabsorber materials, and photocatalysts, some of which have been experimentally verified. Machine learning in combination with first-principles calculations has emerged recently as a technique to accelerate and enhance in silico screening. A blend of computation and experimentation with data science toward the development of materials is often referred to as materials informatics and is currently attracting growing interest.

Knitted outer gloves in primary hip and knee arthroplasty.

PubMed

Tanner, J; Wraighte, P; Howard, P

2006-01-01

A randomised trial was carried out to determine the rate of perforation to inner gloves when comparing latex with knitted gloves during hip and knee arthroplasty. Members of the surgical team were randomised to wear either two pairs of latex gloves (standard double gloving) or a knitted glove on top of a latex glove. In addition, participants completed a visual analogue assessment of their overall satisfaction with the gloves. A total of 406 inner gloves were tested for perforations over a four-month period: 23% of inner gloves were perforated when latex outer gloves were used and 6% of inner gloves were perforated when knitted outer gloves were used. In total, there were 64 perforations to the inner gloves; only one of these perforations was detected by the glove wearer. Wearing knitted outer gloves during hip and knee arthroplasty statistically significantly reduces the risk of perforation to inner latex gloves (p<0.0001).

Gallbladder perforation complicating typhoid fever: report of two cases.

PubMed

Gali, B M; Ali, N; Agbese, G O; Duna, V D; Dawha, S D; Ismai, G I; Mohammed, M

2011-01-01

Gallbladder perforation (GBP) is rare and as a complication of typhoid fever is extremely rare. We present two consecutive patients with GBP diagnosed incidentally at laparotomy. Information on the management of two patients with gallbladder perforation seen at Federal Medical Centre Azare in June and October 2008 was extracted from their case records. The two patients were both males aged 13 years and 16 years. They both presented with high fever of more than 2 weeks duration; and abdominal pain and distension. Both patients had features of generalised peritonitis. Pre-operative diagnoses of typhoid enteric perforation were made based on a positive Widal test. Intra-operative findings however, were that of bile peritonitis and gallbladder perforation. Both had cholecystectomy. Culture of the bile aspirate yielded Salmonella typhi. Gallbladder perforation secondary to typhoid fever should be considered as a differential diagnosis in patients with suspected typhoid enteric perforation in typhoid fever endemic region.

Inflow performance relationship for perforated wells producing from solution gas drive reservoir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sukarno, P.; Tobing, E.L.

1995-10-01

The IPR curve equations, which are available today, are developed for open hole wells. In the application of Nodal System Analysis in perforated wells, an accurate calculation of pressure loss in the perforation is very important. Nowadays, the equation which is widely used is Blount, Jones and Glaze equation, to estimate pressure loss across perforation. This equation is derived for single phase flow, either oil or gas, therefore it is not suitable for two-phase production wells. In this paper, an IPR curve equation for perforated wells, producing from solution gas drive reservoir, is introduced. The equation has been developed usingmore » two phase single well simulator combine to two phase flow in perforation equation, derived by Perez and Kelkar. A wide range of reservoir rock and fluid properties and perforation geometry are used to develop the equation statistically.« less

The value of dynamic infrared thermography (DIRT) in perforatorselection and planning of free DIEP flaps.

PubMed

de Weerd, Louis; Weum, Sven; Mercer, James B

2009-09-01

The aim of this paper is to evaluate dynamic infrared thermography (DIRT) as a technique to assist in preoperative perforator selection and planning of free deep inferior epigastric perforator (DIEP) flaps. Twenty-seven patients, scheduled for secondary autologous breast reconstruction with either a free DIEP flap or superficial inferior epigastric artery flap, were included in this prospective clinical study. Preoperative mapping of perforators was performed with a hand-held Doppler and DIRT. A multidetector computer tomography scan was additionally carried out in the last 8 patients. In 23 patients a DIEP flap was used. The perforator as selected from DIRT was a suitable perforator in all DIEP flaps. The location and quality of the selected perforator from DIRT corresponded well with the multidetector computer tomography scan results. Preoperative perforator selection and planning of DIEP flaps is facilitated with the use of DIRT. The technique is noninvasive and easy to use.

Dimensions of stabident intraosseous perforators and needles.

PubMed

Ramlee, R A; Whitworth, J

2001-09-01

Problems can be encountered inserting intraosseous injection needles through perforation sites. This in vitro study examined the variability and size compatibility of Stabident intraosseous injection components. The diameters of 40 needles and perforators from a single Stabident kit were measured in triplicate with a toolmakers microscope. One-way ANOVA revealed that mean needle diameter (0.411 mm) was significantly narrower than mean perforator diameter (0.427 mm) (p < 0.001). A frequency distribution plot revealed that needle diameter followed a normal distribution, indicating tight quality control during manufacture. The diameter of perforators was haphazardly distributed, with a clustering of 15% at the lower limit of the size range. However on no occasion was the diameter of a perforator smaller than that of an injection needle. We conclude that components of the Stabident intraosseous anaesthetic system are size-compatible, but there is greater and more haphazard variability in the diameter of perforators than injection needles.

Application of Layered Perforation Profile Control Technique to Low Permeable Reservoir

NASA Astrophysics Data System (ADS)

Wei, Sun

2018-01-01

it is difficult to satisfy the demand of profile control of complex well section and multi-layer reservoir by adopting the conventional profile control technology, therefore, a research is conducted on adjusting the injection production profile with layered perforating parameters optimization. i.e. in the case of coproduction for multi-layer, water absorption of each layer is adjusted by adjusting the perforating parameters, thus to balance the injection production profile of the whole well section, and ultimately enhance the oil displacement efficiency of water flooding. By applying the relationship between oil-water phase percolation theory/perforating damage and capacity, a mathematic model of adjusting the injection production profile with layered perforating parameters optimization, besides, perforating parameters optimization software is programmed. Different types of optimization design work are carried out according to different geological conditions and construction purposes by using the perforating optimization design software; furthermore, an application test is done for low permeable reservoir, and the water injection profile tends to be balanced significantly after perforation with optimized parameters, thereby getting a good application effect on site.

A Five-Year Review of Perforated Peptic Ulcer Disease in Irrua, Nigeria.

PubMed

Dongo, A E; Uhunmwagho, O; Kesieme, E B; Eluehike, S U; Alufohai, E F

2017-01-01

Peptic ulcer perforation is a common cause of emergency admission and surgery. This is the first study that documents the presentation and outcome of management in Irrua, Nigeria. This is a prospective study of all patients operated on for perforated peptic ulcer between April 1, 2010, and March 31, 2015. A structured questionnaire containing patients' demographics, operation findings, and outcome was filled upon discharge or death. There were 104 patients. 81 males and 23 females (M : F = 3.5 : 1). The age range was between 17 years and 95 years. The mean age was 48.99 years ± SD 16.1 years. The ratio of gastric to duodenal perforation was 1.88 : 1. Perforation was the first sign of peptic ulcer disease in 62 (59.6%). Pneumoperitoneum was detectable with plain radiographs in 95 (91%) patients. 72 (69.2%) had Graham's Omentopexy. Death rate was 17.3%. We note that gastric perforation is a far commoner disease in our environment. Perforation is often the first sign of peptic ulcer disease. We identify fasting amongst Christians as a risk factor for perforation.

Intestinal perforation secondary to ingested foreign bodies: a single-center experience with 38 cases.

PubMed

Lin, Xiao-Kun; Wu, Da-Zhou; Lin, Xiao-Fang; Zheng, Na

2017-05-01

The aim of this study is to report our experience with patients with intestinal perforation secondary to ingested foreign bodies (FBs) who were treated surgically at our institution. Between 2001 and 2015, a total of 38 pediatric patients with the diagnosis of intestinal perforation secondary to FBs were retrospectively reviewed. The series comprised 22 males and 16 females. The average age of the patients was 1.9 years. A definitive preoperative history of the ingestion of FBs was obtained for only eight patients. Crying and abdominal pain were the main clinical manifestations. Perforation repair was performed in 29 patients (76.3%), while enterostomy was utilized in five patients (13.2%) and enterectomy in four patients (10.5%). Five perforations occurred in the large intestine, and 33 perforations occurred in the small intestine with the most common site being the distal ileum. Of the 38 FBs recovered, 26 were food objects, while non-food objects were found in 12 patients. All patients recovered well, except one patient with an intestinal obstruction from adhesions that occurred approximately 1 month after discharge. Clinical performance of intestinal perforation secondary to FBs in children is atypical. Most perforations occur in the small intestine. Primary perforation repair is safe and effective, and better outcomes can be achieved.

[The risk of surgical glove perforations].

PubMed

Hagen, Gerd Ødegård; Arntzen, Halvard

2007-03-29

The increasing prevalence of blood-borne viral diseases has drawn attention to the barrier between the surgical personnel's hands and the patients body fluids during surgery. At present, the typical practice is to use double gloving in orthopaedic surgery, and single gloving in other types of surgery. The main purpose of our study was to estimate and compare the perforation risk in different categories of surgery. In a series of 655 surgical operations covering 5 main categories of surgery, all detected glove perforations were recorded and analysed. Perforations were found in 203 out of 655 operations (31%). The observed perforation frequency was 44.5% in gastrointestinal surgery, 34.7% in orthopaedic surgery, 31.1% in gynaecology, 18.6% in vascular surgery and 9.2% in general surgery. In some subcategories, the frequencies were even higher. In several categories of surgery, we found high perforation frequencies. Perforations in single gloves are often not detected during operations. This may increase the risk of transmission of blood-borne infections, particularly because the time of exposure may be long. Double indicator gloves make the intra-operative detection of perforations easier. Also double gloving is known to significantly reduce the perforation risk. The use of double indicator gloves is recommended in all categories of surgery.

Reconstruction of cubital fossa skin necrosis with radial collateral artery perforator-based propeller flap (RCAP).

PubMed

Chaput, B; Gandolfi, S; Ho Quoc, C; Chavoin, J-P; Garrido, I; Grolleau, J-L

2014-02-01

In recent years, perforator flaps have become an indispensable tool for the reconstruction process. Most recently, "propeller" perforator flaps allow each perforator vessels to become a flap donor site. Once the perforator of interest is identified by acoustic Doppler, the cutaneous or fascio-cutaneous island is designed and then customized according to the principle of "perforasome". So, the flap can be rotated such a propeller, up to 180°. Ideally the donor site is self-closing, otherwise it can be grafted at the same time. Through a skin necrosis secondary to a contrast medium extravasation of the cubital fossa in a 47-year-old man, we describe the use of propeller perforator flap based on a perforator of the radial collateral artery (RCAP). The perforator was identified preoperatively by acoustic Doppler then the flap was adapted bespoke to cover the loss of substance. Ultimately, the result was very satisfying. Well experienced for lower-extremity reconstruction, perforator-based propeller flap are still few reported for upper limb. It is likely that in the future, propeller flap supersede in many indication not only free flaps and locoregional flaps but also, leaving no room for uncertainties of the vascular network, the classic random flaps. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Peritonitis: 10 years' experience in a single surgical unit.

PubMed

Agarwal, Nitin; Saha, Sudipta; Srivastava, Anurag; Chumber, Sunil; Dhar, Anita; Garg, Sanket

2007-01-01

Peritonitis secondary to gut perforation is still one of the commonest surgical emergencies in India and is associated with high morbidity and mortality. The present study examines the aetiology and outcome of peritonitis cases operated on in our surgical unit, and compares our findings with those of previous studies performed between 1981 and 1991. A retrospective study of 260 peritonitis patients operated on in a single surgical unit from 1995 to 2006 was done and data involving clinical presentation, operative findings and post-operative course were studied and analysed. Causes of peritonitis were small bowel perforation (96 ileal, 17 jejunal), peptic perforation (45 duodenal, 16 gastric), appendicular perforation (36), primary peritonitis (8), and others (42). The incidence of major complications was 25% (burst-11%, leak-5%, intraabdominal abscess-5%, multi-organ failure-6.5%). The overall mortality was 10%. High mortality was observed in jejunal, gall bladder and liver abscess perforation cases (> 20%). Histopathological evaluation (143 specimens) revealed tuberculosis in 42 (mostly small bowel), malignancy in 8, and inflammation in the rest. Comparisons with a similar study carried out in the same unit and published in 1995 revealed similar demographic features and mortality, but a change in the most common cause (peptic ulcer perforation to small bowel perforation), and an increased performance of enterostomy compared with primary repair in small bowel perforation and a decrease in the leak rate (13% to 4%). Small bowel perforation is the commonest form of perforation and the mortality rate associated with peritonitis remains unchanged.

Colonic perforation with peritonitis in amoebiasis: a tropical disease with high mortality.

PubMed

Jain, Bhupendra Kumar; Garg, Pankaj Kumar; Kumar, Anjay; Mishra, Kiran; Mohanty, Debajyoti; Agrawal, Vivek

2013-01-01

Invasive colonic amoebiasis presents primarily with dysentery; colonic perforation occurs rarely. Cases of amoebic colonic perforations have been reported sporadically over the past 20 years. A retrospective study was done in the surgical unit of a tertiary care hospital in North India. The case records of those patients were reviewed who underwent exploratory laparotomy from January 2011 to September 2012 and were diagnosed with amoebic colonic perforation on histopathological examination. Details concerning the clinical presentation, investigations, intraoperative findings, operative procedures, and postoperative outcomes were retrieved. Amongst, a total of 186 emergency exploratory laparotomies carried out during the study, 15 patients of amoebic colonic perforation were identified. The median age of the patients was 42 years (IQR 32.0-58.0) and the male to female ratio was 13:2. Previous history of colitis was present in only 1 patient. The preoperative diagnosis was perforation peritonitis in 12 patients; and intussusception, intestinal obstruction and ruptured liver abscess in 1 patient each. Ten patients had single perforation while 5 had multiple colonic perforations. All the patients except one had perforations in the right colon. Bowel resection was performed depending upon the site and extent of the colon involved-right hemicolectomy (8), limited ileocolic resection (6) and sigmoidectomy (1). Bowel continuity could be restored only in 2 of the 15 patients and a stoma was constructed in the remaining 13 patients. The overall mortality rate was found to be 40% (6/15). Amoebic colonic perforation is associated with unusually high mortality.

Preoperative color Doppler assessment in planning of gluteal perforator flaps.

PubMed

Isken, Tonguc; Alagoz, M Sahin; Onyedi, Murat; Izmirli, Hakki; Isil, Eda; Yurtseven, Nagehan

2009-02-01

Gluteal artery perforator flaps have gained popularity due to reliability, preservation of the muscle, versatility in flap design without restricting other flap options, and low donor-site morbidity in ambulatory patients and possibility of enabling future reconstruction in paraplegic patients. But the inconstant anatomy of the vascular plexus around the gluteal muscle makes it hard to predict how many perforators are present, what their volume of blood flow and size are, where they exit the overlying fascia, and what their course through the muscle will be. Without any prior investigations, the reconstructive surgeon could be surprised intraoperatively by previous surgical damage, scar formation, or anatomic variants.For these reasons, to confirm the presence and the location of gluteal perforators preoperatively we have used color Doppler ultrasonography. With the help of the color Doppler ultrasonography 26 patients, 21 men and 5 women, were operated between the years 2002 and 2007. The mean age of patients was 47.7 (age range: 7-77 years). All perforator vessels were marked preoperatively around the defect locations. The perforator based flap that will allow primary closure of the donor site and the defect without tension was planned choosing the perforator that showed the largest flow in color Doppler ultrasonography proximally. Perforators were found in the sites identified with color Doppler ultrasonography in all other flaps. In our study, 94.4% flap viability was ensured in 36 perforator-based gluteal area flaps. Mean flap elevation time was 31.9 minutes. We found that locating the perforators preoperatively helps to shorten the operation time without compromising a reliable viability of the perforator flaps, thus enabling the surgeon easier treatment of pressure sores.

Clinical applications of perforator-based propeller flaps in upper limb soft tissue reconstruction.

PubMed

Ono, Shimpei; Sebastin, Sandeep J; Yazaki, Naoya; Hyakusoku, Hiko; Chung, Kevin C

2011-05-01

A propeller flap is an island flap that moves from one orientation to another by rotating around its vascular axis. The vascular axis is stationary, and flap movement is achieved by revolving on this axis. Early propeller flaps relied on a thick, subcutaneous pedicle to maintain vascularity, and this limited the flap rotation to 90°. With increasing awareness of the location and the vascular territory perfused by cutaneous perforators, it is now possible to design propeller flaps based on a single perforator, so-called "perforator-based propeller flaps." These flaps permit flap rotation up to 180°. We present the results of upper limb soft tissue reconstruction using perforator-based propeller flaps. We constructed a treatment strategy based on the location of the soft tissue defect and the perforator anatomy for expedient wound coverage in 1 stage. All perforator-based propeller flaps derived from 3 institutions that were used for upper limb soft tissue reconstruction were retrospectively analyzed. The parameters studied included the size and location of the defect, the perforator that was used, the size and shape of the flap, the direction (ie, clockwise or counter-clockwise) of flap rotation, the degree of twisting of the perforator, the management of the donor site (ie, linear closure or skin grafting), and flap survival (recorded as the percentage of the flap area that survived). Twelve perforator-based propeller flaps were used to reconstruct upper limb soft tissue defects in 12 patients. Six different perforators were used as vascular pedicles. The donor defects of 11 flaps could be closed primarily. One flap was partially lost in a patient with electrical burns. Perforator-based propeller flaps provide a reliable option for covering small- to medium-size upper limb soft tissue defects. Copyright © 2011 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Cost effective management of duodenal ulcers in Uganda: interventions based on a series of seven cases.

PubMed

Nzarubara, Gabriel R

2005-03-01

Our understanding of the cause and treatment of peptic ulcer disease has changed dramatically over the last couple of decades. It was quite common some years ago to treat chronic ulcers surgically. These days, the operative treatment is restricted to the small proportion of ulcer patients who have complications such as perforation. The author reports seven cases of perforated duodenal ulcers seen in a surgical clinic between 1995 and 2001. Recommendations on the criteria for selecting the appropriate surgical intervention for patients with perforated duodenal ulcer are given. To decide on the appropriate surgical interventions for patients with perforated duodenal ulcer. These are case series of 7 patients who presented with perforated duodenal ulcers without a history of peptic ulcer disease. Seven patients presented with perforated duodenal ulcer 72 hours after perforation in a specialist surgical clinic in Kampala were analyzed. Appropriate management based on these patients is suggested. These patients were initially treated in upcountry clinics for acute gastritis from either alcohol consumption or suspected food poisoning. There was no duodenal ulcer history. As a result, they came to specialist surgical clinic more than 72 hours after perforation. Diagnosis of perforated duodenal ulcer was made and they were operated using the appropriate surgical intervention. Diagnosis of hangovers and acute gastritis from alcoholic consumption or suspected food poisoning should be treated with suspicion because the symptoms and signs may mimic perforated peptic ulcer in "silent" chronic ulcers. The final decision on the appropriate surgical intervention for patients with perforated duodenal ulcer stratifies them into two groups: The previously fit patients who have relatively mild physiological compromise imposed on previously healthy organ system by the perforation can withstand the operative stress of definitive procedure. The Second category includes patients who are critically ill, who poorly tolerate any operation and hence poor surgical risks. These require urgent, adequate resuscitation and simple suture with omental patch.

Clinical Tests Combined with Color Doppler Versus Color Doppler Alone in Identifying Incompetent Perforator Veins of the Lower Limb: A Prospective Analytical Study.

PubMed

Sureshkumar, Sathasivam; Vignesh, Narayan; Venkatachalam, J; Vijayakumar, Chellappa; Sudharsanan, Sundaramurthi

2018-01-05

Background The color Doppler, a better investigation to identify the perforators objectively has replaced the clinical examination for the same. However, this has led to a significant number of negative explorations and cosmetic disfigurement. Objective To compare the efficacy of the clinical tests combined with the color Doppler versus color Doppler alone to identify the perforator incompetence during the surgery for primary varicose veins of the lower limb. Methods This was a prospective analytical study, including 61 lower limb varicose vein patients who belonged to the Clinical-Etiology-Anatomy-Pathophysiology (CEAP) class four-six, planned for the surgical treatment for perforator incompetence, excluding those requiring additional vascular or nonvascular procedure, recurrent varicose veins and those who had injection sclerotherapy prior to the surgery. The clinical tests, including Trendelenburg's test, multiple tourniquet tests and, the Fegan's tests were performed and incompetent perforators were marked on a template as 'C' to indicate the clinically positive perforator incompetence. The patients were then examined with the color Doppler ultrasound and the pathological incompetent perforators were marked as 'D'. The surgical management of the perforator incompetence was done by stab ligation. The incision was made in the color Doppler 'D' marked sites as it has been the standard protocol. The number of incompetent perforators identified during the surgical exploration were categorized as 'D' positive or 'C' and 'D' positive and were recorded in the specified proforma. Results It was found that the mean number of the perforator incompetence identified by the color Doppler alone was 8.2 whereas during the surgery, only a mean of six perforators was identified, leading to 20 unnecessary explorations per 10 patients (8.2 vs. 6; mean difference 2.229; P <0.001). The mean number of the perforator incompetence identified by the color Doppler combined with the clinical tests was 4.5 and during the surgery, a mean of four perforators was identified (4.5 vs. 4; mean difference 0.377; P <0.001). The color Doppler combined with the clinical examination lead to only four unnecessary explorations per 10 patients. Conclusion A combination of both the clinical tests and the color Doppler ultrasound has a higher accuracy in detecting perforator incompetence and can reduce the number of negative explorations by the rate of 16 unnecessary explorations per 10 patients.

Tympanic membrane perforation after combat blast exposure in Iraq: a poor biomarker of primary blast injury.

PubMed

Harrison, Corey D; Bebarta, Vikhyat S; Grant, Gerald A

2009-07-01

The US military has reported over 10,000 improvised explosive device attacks attributing to over 400 deaths in Iraq in 2005. Otologic blast injury and tympanic membrane (TM) perforation have traditionally been used as a predictor, or biomarker, of serious or occult primary blast injury (PBI). Although combat injuries from the US-Iraq conflict have been described, the utility of TM perforation as a marker of PBI has not. The objective of this study is to determine the incidence of tympanic perforation in patients subject to blast exposures and describe its utility as a biomarker of more serious primary barotrauma, as observed at a US military hospital in Iraq. In our institutional review board-approved study, all patients during a 30-day period who arrived at a tertiary US military hospital in Iraq were evaluated. All patients with blast injures were identified on arrival to the hospital emergency department and were followed up through their hospital course and evacuation to the United States to assure they received proper otolaryngology evaluation and follow-up. Demographic data and manifestations of PBI (TM perforation, pneumothorax, pulmonary contusion, nonpenetrating facial sinus injury, and bowel perforation) and other combat injuries were recorded. The diagnostic tests and clinical examination findings used to identify these complications were also recorded. One hundred sixty-seven patients were enrolled over 30 days. All blast exposures resulted from primary or secondary explosions from munitions used in combat. This included both combatants and civilians. All patients were men. The mean patient age was 28 years (range, 12-55 years). Sixteen percent (27 of 167) of blast-exposed patients had TM perforation. Thirteen of 27 patients with perforations had bilateral perforations. Twelve of 167 patients (7%) had PBI. Six of 12 patients (50%) with PBI had TM perforation. The use of TM perforation as a biomarker for PBI resulted in a sensitivity of 50% (95% CI, 22-78%) and specificity of 87% (95% CI, 81-92%). Both TM perforation and PBI are rare with improvised explosive devices and other explosive devices in the current Iraqi-US conflict. Contrary to previous belief and management guidelines, TM perforation had low sensitivity for serious or occult PBI and was not a good biomarker. On the basis of the findings of this study, the absence of TM perforation does not appear to exclude other serious PBI.

Caliste 64: detection unit of a spectro imager array for a hard x-ray space telescope

NASA Astrophysics Data System (ADS)

Limousin, O.; Meuris, A.; Lugiez, F.; Gevin, Olivier; Pinsard, F.; Blondel, C.; Le Mer, I.; Delagnes, E.; Vassal, M. C.; Soufflet, F.; Bocage, R.; Penquer, A.; Billot, M.

2017-11-01

In the frame of the hard X-ray Simbol-X observatory, a joint CNES-ASI space mission to be flown in 2014, a prototype of miniature Cd(Zn)Te camera equipped with 64 pixels has been designed. The device, called Caliste 64, is a spectro-imager with high resolution event timetagging capability. Caliste 64 integrates a Cd(Zn)Te semiconductor detector with segmented electrode and its front-end electronics made of 64 independent analog readout channels. This 1 × 1 × 2 cm3 camera, able to detect photons in the range from 2 keV up to 250 keV, is an elementary detection unit juxtaposable on its four sides. Consequently, large detector array can be made assembling a mosaic of Caliste 64 units. Electronics readout module is achieved by stacking four IDeF-X V1.1 ASICs, perpendicular to the detection plane. We achieved good noise performances, with a mean Equivalent Noise Charge of 65 electrons rms over the 64 channels. For the first prototypes, we chose Pt//CdTe//Al/Ti/Au Schottky detectors because of their very low dark current and excellent spectroscopic performances. Recently a Caliste 64 prototype has been also equipped with a 2 mm thick Au//CdZnTe//Au detector. This paper presents the performances of these four prototypes and demonstrates spectral performances better than 1 keV fwhm at 59.54 keV when the samples are moderately cooled down to -10°C.

[Iatrogen perforation of the rectum after colon radiography].

PubMed

Eggum, R; Kressner, U; Haffner, J

1998-05-10

Perforation of the rectum following barium enema is relatively rare, occurring in 1 of 3,000 procedures. Colorectal perforation is a serious condition and early diagnosis is of paramount importance in order to avoid any delay in treating the patient. Direct suture of the perforation, lavage, presacral drainage and stomia are the preferred methods of primary surgical treatment.

Esophageal stent placement as a therapeutic option for iatrogenic esophageal perforation in children.

PubMed

Ahmad, Alsafadi; Wong Kee Song, Louis M; Absah, Imad

2016-01-01

Iatrogenic esophageal perforation (IEP) is a potentially serious adverse event of interventional endoscopy. The approach to IEP varies from surgical repair for large perforations to conservative treatment for small contained perforations. We report a case of an 18-month-old girl with congenital esophageal stenosis suffering a large esophageal perforation after a trial of stricture dilatation, which was successfully managed by the placement of fully covered stent. Hence, in selected cases, esophageal stent placement is a feasible alternative to invasive surgery in managing IEP.

Conservative Management of an Epicardial Collateral Perforation During Retrograde Chronic Total Occlusion Percutaneous Coronary Intervention.

PubMed

Ngo, Christian; Christopoulos, George; Brilakis, Emmanouil S

2016-01-01

Coronary artery perforation is a highly feared complication of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) and can lead to pericardial effusion, tamponade, and, rarely, emergent cardiac surgery. Perforation of epicardial collaterals during retrograde CTO-PCI may be particularly challenging to treat, as embolization from both sides of the perforation may be required to control the bleeding. However, conservative measures can occasionally be effective. We present a case of epicardial collateral vessel perforation that was managed conservatively with anticoagulation reversal.

Malignant gastric lymphoma with spontaneous perforation.

PubMed

Shimada, Satoko; Gen, Tokichi; Okamoto, Hiroyuki

2013-01-17

Malignant gastric lymphoma, accounting only for 1% of primary gastric carcinoma, is usually a diffuse large B-cell lymphoma. Toyota et al reported that 37% of gastric perforations involved malignancy, generally gastric carcinoma. Fukuda et al found that less than 5% of malignant gastric lymphomas perforate. While it is relatively well known that perforations often take place during chemotherapy, they are rare in patients not receiving chemotherapy. To our knowledge, spontaneous perforation is rare in gastric malignant lymphoma, having been reported in the Japanese literature only 26 times, including this case, in the last 25 years.

Laparoscopic pyloroplasty for perforated peptic ulcer.

PubMed

Grišin, Edvard; Mikalauskas, Saulius; Poškus, Tomas; Jotautas, Valdemaras; Strupas, Kęstutis

2017-09-01

Peptic ulcer is a common disease affecting millions of people every year. Despite improved understanding and treatment of the disease, the number of patients admitted with duodenal peptic ulcer perforation has not decreased. Deaths from peptic ulcer disease overcome other common emergency situations. Laparoscopic repair of the perforated peptic ulcer (PPU) is the gold standard approach for simple perforation. However, in patients with large perforated chronic ulcers laparotomy with pyloroplasty is the standard treatment. It is generally accepted to perform open surgery in PPU emergencies because of the greater knowledge and experience gathered over the past decades and less potential harm for the patient or surgical complications. We present a case of successful laparoscopic pyloroplasty of a perforated duodenal ulcer with stenosis.

Giant trochanteric pressure sore: Use of a pedicled chimeric perforator flap for cover

PubMed Central

Mehrotra, Sandeep

2009-01-01

Pressure sores are increasing in frequency commensurate with an ageing population with multi-system disorders and trauma. Numerous classic options are described for providing stable wound cover. With the burgeoning knowledge on perforator anatomy, recent approaches focus on the use of perforator-based flaps in bedsore surgery. A giant neglected trochanteric pressure sore in a paraplegic is presented. Since conventional options of reconstruction appeared remote, the massive ulcer was successfully managed by a chimeric perforator-based flap. The combined muscle and fasciocutaneous flaps were raised as separate paddles based on the anterolateral thigh perforator branches and provided stable cover without complications. Perforators allow versatility in managing complex wounds without compromising on established principles. PMID:19881035

Laparoscopic pyloroplasty for perforated peptic ulcer

PubMed Central

Mikalauskas, Saulius; Poškus, Tomas; Jotautas, Valdemaras; Strupas, Kęstutis

2017-01-01

Peptic ulcer is a common disease affecting millions of people every year. Despite improved understanding and treatment of the disease, the number of patients admitted with duodenal peptic ulcer perforation has not decreased. Deaths from peptic ulcer disease overcome other common emergency situations. Laparoscopic repair of the perforated peptic ulcer (PPU) is the gold standard approach for simple perforation. However, in patients with large perforated chronic ulcers laparotomy with pyloroplasty is the standard treatment. It is generally accepted to perform open surgery in PPU emergencies because of the greater knowledge and experience gathered over the past decades and less potential harm for the patient or surgical complications. We present a case of successful laparoscopic pyloroplasty of a perforated duodenal ulcer with stenosis. PMID:29062455

Clinical findings and results of diagnostic imaging in 82 dogs with gastrointestinal ulceration.

PubMed

Fitzgerald, E; Barfield, D; Lee, K C L; Lamb, C R

2017-04-01

To describe clinical and imaging findings in dogs with confirmed gastrointestinal ulceration, to compare findings in dogs with perforated and non-perforated ulcers and to estimate the sensitivities of radiography, ultrasonography and computed tomography (CT) for gastrointestinal ulceration and perforation. Retrospective review of medical records of 82 dogs that had a macroscopic ulcer in the gastric or intestinal mucosa diagnosed directly at endoscopy, surgery or necropsy and had survey radiography, ultrasonography or a CT scan of the abdomen during the same period of hospitalisation. The most frequent clinical signs were vomiting in 88% dogs, haematemesis in 32%, melaena in 31% and weight loss in 7%. The most frequent imaging findings in dogs with non-perforated ulcers were gastrointestinal mural lesion in 56%, mucosal defect compatible with an ulcer in 44% and peritoneal fluid in 21%. In dogs with perforated ulcers the most frequent imaging findings were peritoneal fluid in 83%, gastrointestinal mural lesion in 48%, peritoneal gas in 31% and mucosal defect compatible with an ulcer in 29%. Sensitivities of radiography, ultrasonography and CT were 30, 65 and 67% in dogs with non-perforated ulcers and 79, 86 and 93% in dogs with perforated ulcers, respectively. In dogs with non-perforated ulcers, survey radiography was usually negative whereas ultrasonography and CT frequently enabled detection of the site of the ulcer; in dogs with perforated ulcers, radiography was frequently positive for peritoneal gas and CT was a sensitive modality for both the ulcer and signs of perforation. © 2017 British Small Animal Veterinary Association.

Anatomical study of the popliteal artery perforator-based propeller flap and its clinical application.

PubMed

Onishi, Tadanobu; Shimizu, Takamasa; Omokawa, Shohei; Sananpanich, Kanit; Kido, Akira; Mahakkanukrauh, Pasuk; Tanaka, Yasuhito

2018-05-30

There is lack of anatomical information regarding cutaneous perforator of the popliteal artery and its connections with the descending branch of the inferior gluteal and profunda femoris arteries. We aimed to evaluate the anatomical basis of popliteal artery perforator-based propeller flap from the posterior thigh region and to demonstrate our experience utilizing this flap. Ten fresh cadaveric lower extremities were dissected following injection of a silicone compound into the femoral artery. We investigated the number, location, length, and diameter of cutaneous perforators of the popliteal artery. Based on the results, we treated three cases with a large soft tissue defect around the knee using popliteal artery perforator-based propeller flap. We found a mean of 1.9 cutaneous perforators arising from the popliteal artery with a mean pedicle length of 6 cm and a mean arterial internal diameter of 0.9 mm, which were located at an average of 4 cm proximal to the bicondylar line. The most distal perforator consistently arose along the small saphenous vein and connected proximally with concomitant artery of the posterior femoral cutaneous nerve, forming a connection with perforating arteries of the profunda femoris artery. A mean of 4.5 cutaneous perforators branched from the arterial connection sites. All clinical cases healed without any complications. The popliteal artery perforator-based propeller flap is reliable for reconstruction of soft tissue defects around the knee. The flap should include the deep fascia and concomitant artery along with the posterior femoral cutaneous nerve for maintaining the blood supply.

Parasacral Perforator Flaps for Reconstruction of Sacral Pressure Sores.

PubMed

Lin, Chin-Ta; Chen, Shih-Yi; Chen, Shyi-Gen; Tzeng, Yuan-Sheng; Chang, Shun-Cheng

2015-07-01

Despite advances in reconstruction techniques, pressure sores continue to present a challenge to the plastic surgeon. The parasacral perforator flap is a reliable flap that preserves the entire contralateral side as a future donor site. On the ipsilateral side, the gluteal muscle itself is preserved and all flaps based on the inferior gluteal artery are still possible. We present our experience of using parasacral perforator flaps in reconstructing sacral defects. Between August 2004 and January 2013, 19 patients with sacral defects were included in this study. All the patients had undergone surgical reconstruction of sacral defects with a parasacral perforator flap. The patients' sex, age, cause of sacral defect, flap size, flap type, numbers of perforators used, rotation angle, postoperative complications, and hospital stay were recorded. There were 19 parasacral perforator flaps in this series. All flaps survived uneventfully except for 1 parasacral perforator flap, which failed because of methicillin-resistant Staphylococcus aureus infection. The overall flap survival rate was 95% (18/19). The mean follow-up period was 17.3 months (range, 2-24 months). The average length of hospital stay was 20.7 days (range, 9-48 days). No flap surgery-related mortality was found. Also, there was no recurrence of sacral pressure sores or infected pilonidal cysts during the follow-up period. Perforator-based flaps have become popular in modern reconstructive surgery because of low donor-site morbidity and good preservation of muscle. Parasacral perforator flaps are durable and reliable in reconstructing sacral defects. We recommend the parasacral perforator flap as a good choice for reconstructing sacral defects.

Terahertz Absorption and Circular Dichroism Spectroscopy of Solvated Biopolymers

NASA Astrophysics Data System (ADS)

Xu, Jing; Plaxco, Kevin; Allen, S. James

2006-03-01

Biopolymers are expected to exhibit broad spectral features in the terahertz frequency range, corresponding to their functionally relevant, global and sub-global collective vibrational modes with ˜ picosecond timescale. Recent advances in terahertz technology have stimulated researchers to employ terahertz absorption spectroscopy to directly probe these postulated collective modes. However, these pioneering studies have been limited to dry and, at best, moist samples. Successful isolation of low frequency vibrational activities of solvated biopolymers in their natural water environment has remained elusive, due to the overwhelming attenuation of the terahertz radiation by water. Here we have developed a terahertz absorption and circular dichroism spectrometer suitable for studying biopolymers in biologically relevant water solutions. We have precisely isolated, for the first time, the terahertz absorption of solvated prototypical proteins, Bovine Serum Albumin and Lysozyme, and made important direct comparison to the existing molecular dynamic simulations and normal mode calculations. We have also successfully demonstrated the magnetic circular dichroism in semiconductors, and placed upper bounds on the terahertz circular dichroism signatures of prototypical proteins in water solution.

Compact lidar system using laser diode, binary continuous wave power modulation, and an avalanche photodiode-based receiver controlled by a digital signal processor

NASA Astrophysics Data System (ADS)

Ardanuy, Antoni; Comerón, Adolfo

2018-04-01

We analyze the practical limits of a lidar system based on the use of a laser diode, random binary continuous wave power modulation, and an avalanche photodiode (APD)-based photereceiver, combined with the control and computing power of the digital signal processors (DSP) currently available. The target is to design a compact portable lidar system made all in semiconductor technology, with a low-power demand and an easy configuration of the system, allowing change in some of its features through software. Unlike many prior works, we emphasize the use of APDs instead of photomultiplier tubes to detect the return signal and the application of the system to measure not only hard targets, but also medium-range aerosols and clouds. We have developed an experimental prototype to evaluate the behavior of the system under different environmental conditions. Experimental results provided by the prototype are presented and discussed.

A high temperature hybrid photovoltaic-thermal receiver employing spectral beam splitting for linear solar concentrators

NASA Astrophysics Data System (ADS)

Mojiri, Ahmad; Stanley, Cameron; Rosengarten, Gary

2015-09-01

Hybrid photovoltaic/thermal (PV-T) solar collectors are capable of delivering heat and electricity concurrently. Implementing such receivers in linear concentrators for high temperature applications need special considerations such as thermal decoupling of the photovoltaic (pv) cells from the thermal receiver. Spectral beam splitting of concentrated light provides an option for achieving this purpose. In this paper we introduce a relatively simple hybrid receiver configuration that spectrally splits the light between a high temperature thermal fluid and silicon pv cells using volumetric light filtering by semi-conductor doped glass and propylene glycol. We analysed the optical performance of this device theoretically using ray tracing and experimentally through the construction and testing of a full scale prototype. The receiver was mounted on a commercial parabolic trough concentrator in an outdoor experiment. The prototype receiver delivered heat and electricity at total thermal efficiency of 44% and electrical efficiency of 3.9% measured relative to the total beam energy incident on the primary mirror.

Comparison of technologies for nano device prototyping with a special focus on ion beams: A review

NASA Astrophysics Data System (ADS)

Bruchhaus, L.; Mazarov, P.; Bischoff, L.; Gierak, J.; Wieck, A. D.; Hövel, H.

2017-03-01

Nano device prototyping (NDP) is essential for realizing and assessing ideas as well as theories in the form of nano devices, before they can be made available in or as commercial products. In this review, application results patterned similarly to those in the semiconductor industry (for cell phone, computer processors, or memory) will be presented. For NDP, some requirements are different: thus, other technologies are employed. Currently, in NDP, for many applications direct write Gaussian vector scan electron beam lithography (EBL) is used to define the required features in organic resists on this scale. We will take a look at many application results carried out by EBL, self-organized 3D epitaxy, atomic probe microscopy (scanning tunneling microscope/atomic force microscope), and in more detail ion beam techniques. For ion beam techniques, there is a special focus on those based upon liquid metal (alloy) ion sources, as recent developments have significantly increased their applicability for NDP.

Down to 2 nm Ultra Shallow Junctions : Fabrication by IBS Plasma Immersion Ion Implantation Prototype PULSION registered

DOE Office of Scientific and Technical Information (OSTI.GOV)

Torregrosa, Frank; Etienne, Hasnaa; Mathieu, Gilles

Classical beam line implantation is limited in low energies and cannot achieve P+/N junctions requirements for <45nm node. Compared to conventional beam line ion implantation, limited to a minimum of about 200 eV, the efficiency of Plasma Immersion Ion Implantation (PIII) is no more to prove for the realization of Ultra Shallow Junctions (USJ) in semiconductor applications: this technique allows to get ultimate shallow profiles (as implanted) thanks to no lower limitation of energy and offers high dose rate. In the field of the European consortium NANOCMOS, Ultra Shallow Junctions implanted on a semi-industrial PIII prototype (PULSION registered ) designedmore » by the French company IBS, have been studied. Ultra shallow junctions implanted with BF3 at acceleration voltages down to 20V were realized. Contamination level, homogeneity and depth profile are studied. The SIMS profiles obtained show the capability to make ultra shallow profiles (as implanted) down to 2nm.« less

Perforating arteries originating from the posterior communicating artery: a 7.0-Tesla MRI study.

PubMed

Conijn, Mandy M A; Hendrikse, Jeroen; Zwanenburg, Jaco J M; Takahara, Taro; Geerlings, Mirjam I; Mali, Willem P Th M; Luijten, Peter R

2009-12-01

The aim of this study was to investigate the ability of time-of-flight (TOF) magnetic resonance (MR) angiography at 7.0 Tesla to show the perforating branches of the posterior communicating artery (PCoA), and to investigate the presence of such visible perforating branches in relation to the size of the feeding PCoA. The secondary aim was to visualise and describe the anterior choroidal artery and the perforating branches of the P1-segment of posterior cerebral artery (P1). Forty-six healthy volunteers underwent TOF MR angiography at 7.0 Tesla. With 7.0-Tesla imaging, we visualised for the first time perforating arteries originating from the PCoA in vivo without the use of contrast agents. A perforating artery from the PCoA was found in a large proportion of the PCoAs (64%). The presence was associated with a larger diameter of the underlying PCoA (1.23 versus 1.06 mm, P = 0.03). The anterior choroidal artery was visible bilaterally in all participants. In 83% of all P1s, one or two perforating branches were visible. Non-invasive assessment of the perforating arteries of the PCoA together with the anterior choroidal artery and the perforating arteries of the P1 may increase our understanding of infarcts in the deep brain structures supplied by these arteries.

Bowel perforation detection using metabolic fluorescent chlorophylls

NASA Astrophysics Data System (ADS)

Han, Jung Hyun; Jo, Young Goun; Kim, Jung Chul; Choi, Sujeong; Kang, Hoonsoo; Kim, Yong-Chul; Hwang, In-Wook

2016-03-01

Thus far, there have been tries of detection of disease using fluorescent materials. We introduce the chlorophyll derivatives from food plants, which have longer-wavelength emissions (at >650 nm) than those of fluorescence of tissues and organs, for detection of bowel perforation. To figure out the possibility of fluorescence spectroscopy as a monitoring sensor of bowel perforation, fluorescence from organs of rodent models, intestinal and peritoneal fluids of rodent models and human were analyzed. In IVIS fluorescence image of rodent abdominal organ, visualization of perforated area only was possible when threshold of image is extremely finely controlled. Generally, both perforated area of bowel and normal bowel which filled with large amount of chlorophyll derivatives were visualized with fluorescence. The fluorescence from chlorophyll derivatives penetrated through the normal bowel wall makes difficult to distinguish perforation area from normal bowel with direct visualization of fluorescence. However, intestinal fluids containing chlorophyll derivatives from food contents can leak from perforation sites in situation of bowel perforation. It may show brighter and longer-wavelength regime emissions of chlorophyll derivatives than those of pure peritoneal fluid or bioorgans. Peritoneal fluid mixed with intestinal fluids show much brighter emissions in longer wavelength (at>650 nm) than those of pure peritoneal fluid. In addition, irrigation fluid, which is used for the cleansing of organ and peritoneal cavity, made of mixed intestinal and peritoneal fluid diluted with physiologic saline also can be monitored bowel perforation during surgery.

CMOS Time-Resolved, Contact, and Multispectral Fluorescence Imaging for DNA Molecular Diagnostics

PubMed Central

Guo, Nan; Cheung, Ka Wai; Wong, Hiu Tung; Ho, Derek

2014-01-01

Instrumental limitations such as bulkiness and high cost prevent the fluorescence technique from becoming ubiquitous for point-of-care deoxyribonucleic acid (DNA) detection and other in-field molecular diagnostics applications. The complimentary metal-oxide-semiconductor (CMOS) technology, as benefited from process scaling, provides several advanced capabilities such as high integration density, high-resolution signal processing, and low power consumption, enabling sensitive, integrated, and low-cost fluorescence analytical platforms. In this paper, CMOS time-resolved, contact, and multispectral imaging are reviewed. Recently reported CMOS fluorescence analysis microsystem prototypes are surveyed to highlight the present state of the art. PMID:25365460

Polymeric metallic electrodes for rechargeable battery applications

NASA Technical Reports Server (NTRS)

Somoano, R.

1982-01-01

A review is presented on the status of plastic metal electrodes, emphasizing the use of polyacetylene as a prototype polymeric material. The electrochemical characteristics of polyacetylene are examined; and the potential use of this material, as well as other types of plastic metal electrodes, in batteries is evaluated. Several problem areas which must be solved before polyacetylene can be widely used in battery applications are discussed, including the problem of electrolyte stability, the problem that the depth of discharge and the energy density is limited by the metal-semiconductor transition, and also the poor electrochemical performance of impure material.

Ultrasensitive biomolecular assays with amplifying nanowire FET biosensors

NASA Astrophysics Data System (ADS)

Chui, Chi On; Shin, Kyeong-Sik; Mao, Yufei

2013-09-01

In this paper, we review our recent development and validation of the ultrasensitive electronic biomolecular assays enabled by our novel amplifying nanowire field-effect transistor (nwFET) biosensors. Our semiconductor nwFET biosensor platform technology performs extreme proximity signal amplification in the electrical domain that requires neither labeling nor enzymes nor optics. We have designed and fabricated the biomolecular assay prototypes and developed the corresponding analytical procedures. We have also confirmed their analytical performance in quantitating key protein biomarker in human serum, demonstrating an ultralow limit of detection and concurrently high output current level for the first time.

A Five-Year Review of Perforated Peptic Ulcer Disease in Irrua, Nigeria

PubMed Central

Uhunmwagho, O.; Eluehike, S. U.; Alufohai, E. F.

2017-01-01

Background Peptic ulcer perforation is a common cause of emergency admission and surgery. This is the first study that documents the presentation and outcome of management in Irrua, Nigeria. Patients and Method This is a prospective study of all patients operated on for perforated peptic ulcer between April 1, 2010, and March 31, 2015. A structured questionnaire containing patients' demographics, operation findings, and outcome was filled upon discharge or death. Results There were 104 patients. 81 males and 23 females (M : F = 3.5 : 1). The age range was between 17 years and 95 years. The mean age was 48.99 years ± SD 16.1 years. The ratio of gastric to duodenal perforation was 1.88 : 1. Perforation was the first sign of peptic ulcer disease in 62 (59.6%). Pneumoperitoneum was detectable with plain radiographs in 95 (91%) patients. 72 (69.2%) had Graham's Omentopexy. Death rate was 17.3%. Conclusion We note that gastric perforation is a far commoner disease in our environment. Perforation is often the first sign of peptic ulcer disease. We identify fasting amongst Christians as a risk factor for perforation. PMID:28656171

Semiconductor Reference Oscillator Development for Coherent Detection Optical Remote Sensing Applications

NASA Technical Reports Server (NTRS)

Tratt, David M.; Mansour, Kamjou; Menzies, Robert T.; Qiu, Yueming; Forouhar, Siamak; Maker, Paul D.; Muller, Richard E.

2001-01-01

The NASA Earth Science Enterprise Advanced Technology Initiatives Program is supporting a program for the development of semiconductor laser reference oscillators for application to coherent optical remote sensing from Earth orbit. Local oscillators provide the frequency reference required for active spaceborne optical remote sensing concepts that involve heterodyne (coherent) detection. Two recent examples of such schemes are Doppler wind lidar and tropospheric carbon dioxide measurement by laser absorption spectrometry, both of which are being proposed at a wavelength of 2.05 microns. Frequency-agile local oscillator technology is important to such applications because of the need to compensate for large platform-induced Doppler components that would otherwise interfere with data interpretation. Development of frequency-agile local oscillator approaches has heretofore utilized the same laser material as the transmitter laser (Tm,Ho:YLF in the case of the 2.05-micron wavelength mentioned above). However, a semiconductor laser-based frequency-agile local oscillator offers considerable scope for reduced mechanical complexity and improved frequency agility over equivalent crystal laser devices, while their potentially faster tuning capability suggest the potential for greater scanning versatility. The program we report on here is specifically tasked with the development of prototype novel architecture semiconductor lasers with the power, tunability, and spectral characteristics required for coherent Doppler lidar. The baseline approach for this work is the distributed feedback (DFB) laser, in which gratings are etched into the semiconductor waveguide structures along the entire length of the laser cavity. However, typical DFB lasers at the wavelength of interest have linewidths that exhibit unacceptable growth when driven at the high currents and powers that are required for the Doppler lidar application. Suppression of this behavior by means of corrugation pitch-modulation (using a detuned central section to prevent intensity peaking in the center of the cavity) is currently under investigation to achieve the required performance goals.

Remarkable Enhancement of the Hole Mobility in Several Organic Small‐Molecules, Polymers, and Small‐Molecule:Polymer Blend Transistors by Simple Admixing of the Lewis Acid p‐Dopant B(C6F5)3

PubMed Central

Panidi, Julianna; Paterson, Alexandra F.; Khim, Dongyoon; Fei, Zhuping; Han, Yang; Tsetseris, Leonidas; Vourlias, George; Patsalas, Panos A.; Heeney, Martin

2017-01-01

Abstract Improving the charge carrier mobility of solution‐processable organic semiconductors is critical for the development of advanced organic thin‐film transistors and their application in the emerging sector of printed electronics. Here, a simple method is reported for enhancing the hole mobility in a wide range of organic semiconductors, including small‐molecules, polymers, and small‐molecule:polymer blends, with the latter systems exhibiting the highest mobility. The method is simple and relies on admixing of the molecular Lewis acid B(C6F5)3 in the semiconductor formulation prior to solution deposition. Two prototypical semiconductors where B(C6F5)3 is shown to have a remarkable impact are the blends of 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl)anthradithiophene:poly(triarylamine) (diF‐TESADT:PTAA) and 2,7‐dioctyl[1]‐benzothieno[3,2‐b][1]benzothiophene:poly(indacenodithiophene‐co‐benzothiadiazole) (C8‐BTBT:C16‐IDTBT), for which hole mobilities of 8 and 11 cm2 V−1 s−1, respectively, are obtained. Doping of the 6,13‐bis(triisopropylsilylethynyl)pentacene:PTAA blend with B(C6F5)3 is also shown to increase the maximum hole mobility to 3.7 cm2 V−1 s−1. Analysis of the single and multicomponent materials reveals that B(C6F5)3 plays a dual role, first acting as an efficient p‐dopant, and secondly as a microstructure modifier. Semiconductors that undergo simultaneous p‐doping and dopant‐induced long‐range crystallization are found to consistently outperform transistors based on the pristine materials. Our work underscores Lewis acid doping as a generic strategy towards high performance printed organic microelectronics. PMID:29375962

A Case of Stercoral Perforation Detected on CT Requiring Proctocolectomy in a Heroin-Dependent Patient

PubMed Central

Alam, Fahreyar; Planner, Andy; Alexander, Roderick J.

2016-01-01

Stercoral perforation of the colon is rare but carries with it significant morbidity and mortality. Stercoral perforation usually occurs in elderly, immobile patients with chronic constipation. In this manuscript, we report the case of stercoral perforation in a patient due to chronic heroin dependence. We report the case of a 56-year-old male patient with stercoral perforation, diagnosed by computed tomography, secondary to heroin dependence, requiring proctocolectomy and an end ileostomy. There are very few reports in the literature describing cases of stercoral perforation and questions have been asked about the importance of preoperative cross-sectional imaging. In our case, the diagnosis of stercoral perforation was made only on CT. Although this is not the first such case to be reported, it is significant as preoperative CT imaging was influential not only in determining the aetiology of the abdominal distension seen on the plain film, but also in detecting the pneumoperitoneum which was not evident clinically or on plain radiographs. PMID:27830103

A Case of Stercoral Perforation Detected on CT Requiring Proctocolectomy in a Heroin-Dependent Patient.

PubMed

Seligman, William H; Alam, Fahreyar; Planner, Andy; Alexander, Roderick J

2016-01-01

Stercoral perforation of the colon is rare but carries with it significant morbidity and mortality. Stercoral perforation usually occurs in elderly, immobile patients with chronic constipation. In this manuscript, we report the case of stercoral perforation in a patient due to chronic heroin dependence. We report the case of a 56-year-old male patient with stercoral perforation, diagnosed by computed tomography, secondary to heroin dependence, requiring proctocolectomy and an end ileostomy. There are very few reports in the literature describing cases of stercoral perforation and questions have been asked about the importance of preoperative cross-sectional imaging. In our case, the diagnosis of stercoral perforation was made only on CT. Although this is not the first such case to be reported, it is significant as preoperative CT imaging was influential not only in determining the aetiology of the abdominal distension seen on the plain film, but also in detecting the pneumoperitoneum which was not evident clinically or on plain radiographs.

Clinical features and outcomes of delayed perforation after endoscopic submucosal dissection for early gastric cancer.

PubMed

Hanaoka, N; Uedo, N; Ishihara, R; Higashino, K; Takeuchi, Y; Inoue, T; Chatani, R; Hanafusa, M; Tsujii, Y; Kanzaki, H; Kawada, N; Iishi, H; Tatsuta, M; Tomita, Y; Miyashiro, I; Yano, M

2010-12-01

Perforation is a major complication of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC). However, there have been no reports on delayed perforation after ESD for EGC. We aimed to elucidate the incidence and outcomes of delayed perforation after ESD. Clinical courses in 1159 consecutive patients with 1329 EGCs who underwent ESD were investigated. Delayed perforation occurred in six patients (0.45 %). All these patients had complete en bloc resection without intraoperative perforation during ESD. Five of six perforations were located in the upper third of the stomach, while one lesion was found in the middle third. Symptoms of peritoneal irritation with rebound tenderness presented within 24 h after ESD in all cases. One patient did not require surgery because the symptoms were localized, and recovered with conservative antibiotic therapy by nasogastric tube placement. The remaining five patients required emergency surgery. There was no mortality in this case series. © Georg Thieme Verlag KG Stuttgart · New York.

Neonatal gastric perforation.

PubMed

Kuremu, R T; Hadley, G P; Wiersma, R

2004-01-01

Gastric perforation in neonates is a catastrophe associated with high morbidity. Most are due to underlying primary pathology. To review the management of gastric perforation in neonates in Kwa Zulu-Natal, South Africa. Retrospective study of consecutive complete data sets of neonates presenting with gastric perforation. Department of Paediatric Surgery, Nelson R. Mandela School of Medicine, University of Natal, Durban, South Africa. Eight neonates treated for gastric perforation between January 1998 and April 2003. Morbidity and mortality. There was an equal number of males and females. Median birth weight was 2.0 kg with a range of 1.4 to 3.2 kg. Five of the eight neonates were premature. Primary pathologies were associated with perforation in seven of the eight neonates. Prematurity, low birth weight and pneumonia were contributing factors to the poor outcome. Sepsis was a complication in seven of the eight neonates leading to their death (88% mortality). Active perinatal management, early treatment of primary pathologies, and protection of the stomach against distension in neonates at risk are essential in the management of neonatal gastric perforation.

Management of ileal perforation due to typhoid fever.

PubMed Central

Kim, J P; Oh, S K; Jarrett, F

1975-01-01

The results of the surgical management of 161 cases of ileal perforation due to typhoid fever are presented. Most were seen after an illness of 2-4 weeks, and because of delays in seeking hospital admission, more than half were explored more than 24 hours after their perforation occurred. All patients were prepared for operation with nasogastric suction, intravenous fluids, and antibiotics. At laparotomy, 80% had considerable quantities of pus and small bowel contents in the peritoneal cavity and the remainder had localized abscesses; there were no instances of localization of the perforation. One hundred three of these patients underwent simple closure of their perforations, while 43 underwent small bowel resection, usually because of multiple perforations. Exteriorization or drainage were performed only in patients too sick to tolerate a more appropriate procedure. The overall mortality was 9.9%. The authors believe that typhoid perforations can best be dealt with at operation. Delay in operative intervention adversely affects the survival rate after surgery. Chloramphenicol is used as the drug of choice. PMID:1119873

Laparoscopic repair of perforated peptic duodenal ulcer.

PubMed

Busić, Zeljko; Servis, Draien; Slisurić, Ferdinand; Kristek, Jozo; Kolovrat, Marijan; Cavka, Vlatka; Cavka, Mislav; Cupurdija, Kristijan; Patrlj, Leonardo; Kvesić, Ante

2010-03-01

Although prevalence of peptic ulcer is decreasing, the number of peptic ulcer perforations appears to be unchanged. This complication of peptic ulcer is traditionally surgically treated. In recent years, a number of papers have been published where the authors managed perforated duodenal peptic ulcer in selected patients using laparoscopic approach. Laparoscopic treatment of perforated duodenal ulcer has been described as safe and advantageous compared to open technique but advantages are still not clear due to small number of cases in published studies. Based on these recommendations we decided to establish our own protocol for laparoscopic treatment of perforated peptic duodenal ulcer. In this prospective study we evaluated the first 10 patients in whom we performed laparoscopic repair of perforated duodenal ulcer. There were no conversions to open procedure and no early postoperative complications. The patients were contacted by phone a year after the operation, and all were satisfied with the operation and the appearance of postoperative scars. We regard laparoscopic repair of selected patients with perforated duodenal ulcer as a safe and preferable treatment.

A prototype small CdTe gamma camera for radioguided surgery and other imaging applications.

PubMed

Tsuchimochi, Makoto; Sakahara, Harumi; Hayama, Kazuhide; Funaki, Minoru; Ohno, Ryoichi; Shirahata, Takashi; Orskaug, Terje; Maehlum, Gunnar; Yoshioka, Koki; Nygard, Einar

2003-12-01

Gamma probes have been used for sentinel lymph node biopsy in melanoma and breast cancer. However, these probes can provide only radioactivity counts and variable pitch audio output based on the intensity of the detected radioactivity. We have developed a small semiconductor gamma camera (SSGC) that allows visualisation of the size, shape and location of the target tissues. This study is designed to characterise the performance of the SSGC for radioguided surgery of metastatic lesions and for other imaging applications amenable to the smaller format of this prototype imaging system. The detector head had 32 cadmium telluride semiconductor arrays with a total of 1,024 pixels, and with application-specific integrated circuits (ASICs) and a tungsten collimator. The entire assembly was encased in a lead housing measuring 152 mmx166 mmx65 mm. The effective visual field was 44.8 mmx44.8 mm. The energy resolution and imaging aspects were tested. Two spherical 5-mm- and 15-mm-diameter technetium-99m radioactive sources that had activities of 0.15 MBq and 100 MBq, respectively, were used to simulate a sentinel lymph node and an injection site. The relative detectability of these foci by the new detector and a conventional scintillation camera was studied. The prototype was also examined in a variety of clinical applications. Energy resolution [full-width at half-maximum (FWHM)] for a single element at the centre of the field of view was 4.2% at 140 keV (99mTc), and the mean energy resolution of the CdTe detector arrays was approximately 7.8%. The spatial resolution, represented by FWHM, had a mean value of 1.56 +/- 0.05 mm. Simulated node foci could be visualised clearly by the SSGC using a 15-s acquisition time. In preliminary clinical tests, the SSGC successfully imaged diseases in a variety of tissues, including salivary and thyroid glands, temporomandibular joints and sentinel lymph nodes. The SSGC has significant potential for diagnosing diseases and facilitating subsequent radioguided surgery.

How do tympanic-membrane perforations affect human middle-ear sound transmission?

PubMed

Voss, S E; Rosowski, J J; Merchant, S N; Peake, W T

2001-01-01

Although tympanic-membrane (TM) perforations are common sequelae of middle-ear disease, the hearing losses they cause have not been accurately determined, largely because additional pathological conditions occur in these ears. Our measurements of acoustic transmission before and after making controlled perforations in cadaver ears show that perforations cause frequency-dependent loss that: (1) is largest at low frequencies; (2) increases as perforation size increases; and (3) does not depend on perforation location. The dominant loss mechanism is the reduction in sound-pressure difference across the TM. Measurements of middle-ear air-space sound pressures show that transmission via direct acoustic stimulation of the oval and round windows is generally negligible. A quantitative model predicts the influence of middle-ear air-space volume on loss; with larger volumes, loss is smaller.

Effects of Perforation on Rigid PU Foam Plates: Acoustic and Mechanical Properties

PubMed Central

Lin, Jia-Horng; Chuang, Yu-Chun; Li, Ting-Ting; Huang, Chen-Hung; Huang, Chien-Lin; Chen, Yueh-Sheng; Lou, Ching-Wen

2016-01-01

Factories today are equipped with diverse mechanical equipment in response to rapid technological and industrial developments. Industrial areas located near residential neighborhoods cause massive environmental problems. In particular, noise pollution results in physical and psychological discomfort, and is a seen as invisible and inevitable problem. Thus, noise reduction is a critical and urgent matter. In this study, rigid polyurethane (PU) foam plates undergo perforation using a tapping machine. The mechanical and acoustic properties of these perforated plates as related to perforation rate and perforation depth are evaluated in terms of compression strength, drop-weight impact strength, and sound absorption coefficient. Experimental results indicate that applying the perforation process endows the rigid PU foaming plates with greater load absorption and better sound absorption at medium and high frequencies. PMID:28774119

Effects of Perforation on Rigid PU Foam Plates: Acoustic and Mechanical Properties.

PubMed

Lin, Jia-Horng; Chuang, Yu-Chun; Li, Ting-Ting; Huang, Chen-Hung; Huang, Chien-Lin; Chen, Yueh-Sheng; Lou, Ching-Wen

2016-12-09

Factories today are equipped with diverse mechanical equipment in response to rapid technological and industrial developments. Industrial areas located near residential neighborhoods cause massive environmental problems. In particular, noise pollution results in physical and psychological discomfort, and is a seen as invisible and inevitable problem. Thus, noise reduction is a critical and urgent matter. In this study, rigid polyurethane (PU) foam plates undergo perforation using a tapping machine. The mechanical and acoustic properties of these perforated plates as related to perforation rate and perforation depth are evaluated in terms of compression strength, drop-weight impact strength, and sound absorption coefficient. Experimental results indicate that applying the perforation process endows the rigid PU foaming plates with greater load absorption and better sound absorption at medium and high frequencies.

Surgical Scales: Primary Closure versus Gastric Resection for Perforated Gastric Ulcer - A Surgical Debate.

PubMed

Gachabayov, Mahir; Babyshin, Valentin; Durymanov, Oleg; Neronov, Dmitriy

2017-01-01

Perforated gastric ulcer is one of the most life-threatening complications of peptic ulcer disease with high morbidity and mortality rates. The surgical strategy for gastric perforation in contrast with duodenal perforations often requires consilium and intraoperative debates. The subject of the debate is a 59-year-old male patient who presented with perforated giant gastric ulcer complicated by generalized peritonitis and severe sepsis. The debate is based on a systematized table dividing all factors into three groups and putting them on surgical scales. Pathology-related factors influencing the decision-making are size and site of perforation, local tissue inflammation, signs of malignancy, simultaneous complications of peptic ulcer, peritonitis, and sepsis. Besides these factors, patient- and healthcare-related factors should also be considered.

Surgical Scales: Primary Closure versus Gastric Resection for Perforated Gastric Ulcer - A Surgical Debate

PubMed Central

Gachabayov, Mahir; Babyshin, Valentin; Durymanov, Oleg; Neronov, Dmitriy

2017-01-01

Perforated gastric ulcer is one of the most life-threatening complications of peptic ulcer disease with high morbidity and mortality rates. The surgical strategy for gastric perforation in contrast with duodenal perforations often requires consilium and intraoperative debates. The subject of the debate is a 59-year-old male patient who presented with perforated giant gastric ulcer complicated by generalized peritonitis and severe sepsis. The debate is based on a systematized table dividing all factors into three groups and putting them on surgical scales. Pathology-related factors influencing the decision-making are size and site of perforation, local tissue inflammation, signs of malignancy, simultaneous complications of peptic ulcer, peritonitis, and sepsis. Besides these factors, patient- and healthcare-related factors should also be considered. PMID:28584503

Endoluminal laser delivery mode and wavelength effects on varicose veins in an ex vivo model.

PubMed

Massaki, Ane B M N; Kiripolsky, Monika G; Detwiler, Susan P; Goldman, Mitchel P

2013-02-01

Endovenous laser ablation (EVLA) has been shown to be effective for the elimination of saphenous veins and associated reflux. Mechanism is known to be heat related, but precise way in which heat causes vein ablation is not completely known. This study aimed to determine the effects of various endovenous laser wavelengths and delivery modes on ex vivo human vein both macroscopically and microscopically. We also evaluated whether protected-tip fibers, consisting of prototype silica fibers with a metal tube over the distal end, reduced vein wall perforations compared with non-protected-tip fibers. An ex vivo EVLA model with human veins harvested during ambulatory phlebectomy procedures was used. Six laser fiber combinations were tested: 810 nm continuous wave (CW) diode laser with a flat tip fiber, 810 CW diode laser with a protected tip fiber, 1,320 nm pulsed Nd:YAG laser, 1,310 nm CW diode laser, 1,470 nm CW diode laser, and 2,100 nm pulsed Ho:YAG laser. Perforation or full thickness necrosis of a portion of the vein wall was observed in 5/11 (45%), 0/11 (0%), 3/22 (14%), 7/11 (64%), 4/6 (67%), and 5/10 (50%) of cross-sections of veins treated with the 810 nm CW diode laser with a flat tip fiber, the 810 CW diode laser with a protected tip fiber, the 1,320 nm pulsed Nd:YAG laser, the 1,310 nm CW diode laser, the 1,470 nm CW diode laser, and the 2,100 nm pulsed Ho:YAG laser, respectively. Our results have shown that the delivery mode, pulsed Nd:YAG versus CW, may be just as important as the wavelength. Therefore, the 1,310 nm CW laser may not be equivalent to the 1,320 nm pulsed laser. In addition, protected 810 nm fibers may be less likely to yield wall perforations than their non-protected counterparts. Copyright © 2012 Wiley Periodicals, Inc.

Design and fabrication of vertically-integrated CMOS image sensors.

PubMed

Skorka, Orit; Joseph, Dileepan

2011-01-01

Technologies to fabricate integrated circuits (IC) with 3D structures are an emerging trend in IC design. They are based on vertical stacking of active components to form heterogeneous microsystems. Electronic image sensors will benefit from these technologies because they allow increased pixel-level data processing and device optimization. This paper covers general principles in the design of vertically-integrated (VI) CMOS image sensors that are fabricated by flip-chip bonding. These sensors are composed of a CMOS die and a photodetector die. As a specific example, the paper presents a VI-CMOS image sensor that was designed at the University of Alberta, and fabricated with the help of CMC Microsystems and Micralyne Inc. To realize prototypes, CMOS dies with logarithmic active pixels were prepared in a commercial process, and photodetector dies with metal-semiconductor-metal devices were prepared in a custom process using hydrogenated amorphous silicon. The paper also describes a digital camera that was developed to test the prototype. In this camera, scenes captured by the image sensor are read using an FPGA board, and sent in real time to a PC over USB for data processing and display. Experimental results show that the VI-CMOS prototype has a higher dynamic range and a lower dark limit than conventional electronic image sensors.

MIXS on BepiColombo and its DEPFET based focal plane instrumentation

NASA Astrophysics Data System (ADS)

Treis, J.; Andricek, L.; Aschauer, F.; Heinzinger, K.; Herrmann, S.; Hilchenbach, M.; Lauf, T.; Lechner, P.; Lutz, G.; Majewski, P.; Porro, M.; Richter, R. H.; Schaller, G.; Schnecke, M.; Schopper, F.; Soltau, H.; Stefanescu, A.; Strüder, L.; de Vita, G.

2010-12-01

Focal plane instrumentation based on DEPFET Macropixel devices, being a combination of the Detector-Amplifier structure DEPFET with a silicon drift chamber (SDD), has been proposed for the MIXS (Mercury Imaging X-ray Spectrometer) instrument on ESA's Mercury exploration mission BepiColombo. MIXS images X-ray fluorescent radiation from the Mercury surface with a lightweight X-ray mirror system on the focal plane detector to measure the spatially resolved element abundance in Mercury's crust. The sensor needs to have an energy resolution better than 200 eV FWHM at 1 keV and is required to cover an energy range from 0.5 to 10 keV, for a pixel size of 300×300μm2. Main challenges for the instrument are radiation damage and the difficult thermal environment in the mercury orbit. The production of the first batch of flight devices has been finished at the MPI semiconductor laboratory. Prototype modules have been assembled to verify the electrical properties of the devices; selected results are presented here. The prototype devices, Macropixel prototypes for the SIMBOL-X focal plane, are electrically fully compatible, but have a pixel size of 0.5×0.5 mm2. Excellent homogeneity and near Fano-limited energy resolution at high readout speeds have been observed on these devices.

Design and Fabrication of Vertically-Integrated CMOS Image Sensors

PubMed Central

Skorka, Orit; Joseph, Dileepan

2011-01-01

Technologies to fabricate integrated circuits (IC) with 3D structures are an emerging trend in IC design. They are based on vertical stacking of active components to form heterogeneous microsystems. Electronic image sensors will benefit from these technologies because they allow increased pixel-level data processing and device optimization. This paper covers general principles in the design of vertically-integrated (VI) CMOS image sensors that are fabricated by flip-chip bonding. These sensors are composed of a CMOS die and a photodetector die. As a specific example, the paper presents a VI-CMOS image sensor that was designed at the University of Alberta, and fabricated with the help of CMC Microsystems and Micralyne Inc. To realize prototypes, CMOS dies with logarithmic active pixels were prepared in a commercial process, and photodetector dies with metal-semiconductor-metal devices were prepared in a custom process using hydrogenated amorphous silicon. The paper also describes a digital camera that was developed to test the prototype. In this camera, scenes captured by the image sensor are read using an FPGA board, and sent in real time to a PC over USB for data processing and display. Experimental results show that the VI-CMOS prototype has a higher dynamic range and a lower dark limit than conventional electronic image sensors. PMID:22163860

Approximate Computing Techniques for Iterative Graph Algorithms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panyala, Ajay R.; Subasi, Omer; Halappanavar, Mahantesh

Approximate computing enables processing of large-scale graphs by trading off quality for performance. Approximate computing techniques have become critical not only due to the emergence of parallel architectures but also the availability of large scale datasets enabling data-driven discovery. Using two prototypical graph algorithms, PageRank and community detection, we present several approximate computing heuristics to scale the performance with minimal loss of accuracy. We present several heuristics including loop perforation, data caching, incomplete graph coloring and synchronization, and evaluate their efficiency. We demonstrate performance improvements of up to 83% for PageRank and up to 450x for community detection, with lowmore » impact of accuracy for both the algorithms. We expect the proposed approximate techniques will enable scalable graph analytics on data of importance to several applications in science and their subsequent adoption to scale similar graph algorithms.« less

Frequency-selective surfaces for infrared imaging

NASA Astrophysics Data System (ADS)

Lesmanne, Emeline; Boulard, François; Espiau Delamaestre, Roch; Bisotto, Sylvette; Badano, Giacomo

2017-09-01

Bayer filter arrays are commonly added to visible detectors to achieve multicolor sensitivity. To extend this approach to the infrared range, we present frequency selective surfaces that work in the mid-infrared range (MWIR). They are easily integrated in the device fabrication process and are based on a simple operating principle. They consist of a thin metallic sheet perforated with apertures filled with a high-index dielectric material. Each aperture behaves as a separate resonator. Its size determines the transmission wavelength λ. Using an original approach based on the temporal coupled mode theory, we show that metallic loss is negligible in the infrared range, as long as the filter bandwidth is large enough (typically <λ/10). We develop closed-form expressions for the radiative and dissipative loss rates and show that the transmission of the filter depends solely on their ratio. We present a prototype infrared detector functionalized with one such array of filters and characterize it by electro-optical measurements.

Development of the sonic pump levitation

NASA Technical Reports Server (NTRS)

Dunn, S. A.

1984-01-01

A prototype levitating/positioning device termed the Sonic Pump Levitator was designed, built and successfully tested in full gravity and in the reduced gravity of the parabolic flight regime of the KC-135. Positioning is achieved by timely and appropriate application of gas momentum from one or more of six sonic pumps. The sonic pumps, which are arranged orthogonally in opposed pairs about the levitation region, are activated by an electro-optical, computer controlled, feedback system. The sonic pump is a transducer which is capable of converting sound energy into a directed flow of gas. It consists of a loudspeaker whose face is sealed by a closure perforated by one or more orifices. The diaphragm of the loudspeaker is the only moving part of the sonic pump, no valves being needed. This very low inertia electromechanical device was developed to provide the short response time necessary to keep pace with the demands of computerized position keeping.

Aortic Pseudoaneurysm Secondary to Mediastinitis due to Esophageal Perforation

PubMed Central

Zuluaga, Claudia Patricia; Aluja Jaramillo, Felipe; Velásquez Castaño, Sergio Andrés; Rivera Bernal, Aura Lucía; Granada, Julio Cesar; Carrillo Bayona, Jorge Alberto

2016-01-01

Esophageal perforation is a condition associated with high morbidity and mortality rates; it requires early diagnosis and treatment. The most common complication of esophageal rupture is mediastinitis. There are several case reports in the literature of mediastinitis secondary to esophageal perforation and development of aortic pseudoaneurysm as a complication. We report the case of a patient with an 8-day history of esophageal perforation due to foreign body (fishbone) with mediastinitis and aortic pseudoaneurysm. The diagnosis was made using Computed Tomography (CT) with intravenous and oral water-soluble contrast material. An esophagogastroduodenoscopy did not detect the perforation. PMID:26977330

Perforated Sigmoid Diverticular Disease: a Management Protocol

PubMed Central

Moin, Thajammul

2008-01-01

Background: To develop an evidence-based protocol for the management of perforated sigmoid diverticular disease. Methods: A search of the literature was undertaken. All publications pertaining to perforated sigmoid diverticular disease were analyzed and then categorized according to their level of evidence. Recommendations were then made on the basis of this. Results: Multiple case reports suggest that primary closure of perforation of sigmoid diverticula is safe in the absence of peritoneal contamination. Conclusions: A 2-stage laparoscopic approach incorporating the principles of damage limitation surgery may be a safe strategy in the management of perforated diverticular disease. PMID:18435896

Analysis of colonoscopic perforations at a local clinic and a tertiary hospital.

PubMed

Sagawa, Toshihiko; Kakizaki, Satoru; Iizuka, Haruhisa; Onozato, Yasuhiro; Sohara, Naondo; Okamura, Shinichi; Mori, Masatomo

2012-09-21

To define the clinical characteristics, and to assess the management of colonoscopic complications at a local clinic. A retrospective review of the medical records was performed for the patients with iatrogenic colon perforations after endoscopy at a local clinic between April 2006 and December 2010. Data obtained from a tertiary hospital in the same region were also analyzed. The underlying conditions, clinical presentations, perforation locations, treatment types (operative or conservative) and outcome data for patients at the local clinic and the tertiary hospital were compared. A total of 10  826 colonoscopies, and 2625 therapeutic procedures were performed at a local clinic and 32  148 colonoscopies, and 7787 therapeutic procedures were performed at the tertiary hospital. The clinic had no perforations during diagnostic colonoscopy and 8 (0.3%) perforations were determined to be related to therapeutic procedures. The perforation rates in each therapeutic procedure were 0.06% (1/1609) in polypectomy, 0.2% (2/885) in endoscopic mucosal resection (EMR), and 3.8% (5/131) in endoscopic submucosal dissection (ESD). Perforation rates for ESD were significantly higher than those for polypectomy or EMR (P < 0.01). All of these patients were treated conservatively. On the other hand, three (0.01%) perforation cases were observed among the 24  361 diagnostic procedures performed, and these cases were treated with surgery in a tertiary hospital. Six perforations occurred with therapeutic endoscopy (perforation rate, 0.08%; 1 per 1298 procedures). Perforation rates for specific procedure types were 0.02% (1 per 5500) for polypectomy, 0.17% (1 per 561) for EMR, 2.3% (1 per 43) for ESD in the tertiary hospital. There were no differences in the perforation rates for each therapeutic procedure between the clinic and the tertiary hospital. The incidence of iatrogenic perforation requiring surgical treatment was quite low in both the clinic and the tertiary hospital. No procedure-related mortalities occurred. Performing closure with endoscopic clipping reduced the C-reactive protein (CRP) titers. The mean maximum CRP titer was 2.9 ± 1.6 mg/dL with clipping and 9.7 ± 6.2 mg/dL without clipping, respectively (P < 0.05). An operation is indicated in the presence of a large perforation, and in the setting of generalized peritonitis or ongoing sepsis. Although we did not experience such case in the clinic, patients with large perforations should be immediately transferred to a tertiary hospital. Good relationships between local clinics and nearby tertiary hospitals should therefore be maintained. It was therefore found to be possible to perform endoscopic treatment at a local clinic when sufficient back up was available at a nearby tertiary hospital.

Clinical Tests Combined with Color Doppler Versus Color Doppler Alone in Identifying Incompetent Perforator Veins of the Lower Limb: A Prospective Analytical Study

PubMed Central

Vignesh, Narayan; Venkatachalam, J; Vijayakumar, Chellappa; Sudharsanan, Sundaramurthi

2018-01-01

Background The color Doppler, a better investigation to identify the perforators objectively has replaced the clinical examination for the same. However, this has led to a significant number of negative explorations and cosmetic disfigurement. Objective To compare the efficacy of the clinical tests combined with the color Doppler versus color Doppler alone to identify the perforator incompetence during the surgery for primary varicose veins of the lower limb. Methods This was a prospective analytical study, including 61 lower limb varicose vein patients who belonged to the Clinical-Etiology-Anatomy-Pathophysiology (CEAP) class four-six, planned for the surgical treatment for perforator incompetence, excluding those requiring additional vascular or nonvascular procedure, recurrent varicose veins and those who had injection sclerotherapy prior to the surgery. The clinical tests, including Trendelenburg’s test, multiple tourniquet tests and, the Fegan’s tests were performed and incompetent perforators were marked on a template as ‘C’ to indicate the clinically positive perforator incompetence. The patients were then examined with the color Doppler ultrasound and the pathological incompetent perforators were marked as ‘D’. The surgical management of the perforator incompetence was done by stab ligation. The incision was made in the color Doppler ‘D’ marked sites as it has been the standard protocol. The number of incompetent perforators identified during the surgical exploration were categorized as ‘D’ positive or ’C’ and ‘D’ positive and were recorded in the specified proforma. Results It was found that the mean number of the perforator incompetence identified by the color Doppler alone was 8.2 whereas during the surgery, only a mean of six perforators was identified, leading to 20 unnecessary explorations per 10 patients (8.2 vs. 6; mean difference 2.229; P <0.001). The mean number of the perforator incompetence identified by the color Doppler combined with the clinical tests was 4.5 and during the surgery, a mean of four perforators was identified (4.5 vs. 4; mean difference 0.377; P <0.001). The color Doppler combined with the clinical examination lead to only four unnecessary explorations per 10 patients. Conclusion A combination of both the clinical tests and the color Doppler ultrasound has a higher accuracy in detecting perforator incompetence and can reduce the number of negative explorations by the rate of 16 unnecessary explorations per 10 patients. PMID:29531879

Use of Computed Tomography to Determine Perforation in Patients With Acute Appendicitis.

PubMed

Gaskill, Cameron E; Simianu, Vlad V; Carnell, Jonathan; Hippe, Daniel S; Bhargava, Puneet; Flum, David R; Davidson, Giana H

Urgent appendectomy has long been the standard of care for acute appendicitis. Six randomized trials have demonstrated that antibiotics can safely treat appendicitis, but approximately 1 in 4 of these patients eventually requires appendectomy. Overall treatment success may be limited by complex disease including perforation. Patients׳ success on antibiotic therapy may depend on preoperative identification of complex disease on imaging. However, the effectiveness of computed tomography (CT) in differentiating complex disease including perforated from nonperforated appendicitis remains to be determined. The purpose of this study was to assess the preoperative diagnostic accuracy of CT in determining appendiceal perforation in patients operated for acute appendicitis. We performed a retrospective review of pathology and radiology reports from consecutive patients who presented to the emergency department with suspicion for acute appendicitis between January 2012 and May 2015. CT scans were re-reviewed by abdominal imaging fellowship-trained radiologists using standardized criteria, and the radiologists were blinded to pathology and surgical findings. Radiologists specifically noted presence or absence of periappendiceal gas, abscess, appendicolith, fat stranding, and bowel wall thickening. The overall radiologic impression as well as these specific imaging findings was compared to results of pathology and operative reports. Pathology reports were considered the standard for diagnostic accuracy. Eighty-nine patients (65% male, average age of 34 years) presenting with right lower quadrant pain underwent CT imaging and prompt appendectomy. Final pathology reported perforation in 48% (n = 43) of cases. Radiologic diagnosis of perforation was reported in 9% (n = 8), correctly identifying perforation in 37.5% (n = 3), and incorrectly reporting perforation in 62.5% of nonperforated cases per pathology. Radiology missed 93% (n = 40) of perforations postoperatively diagnosed by pathology. There was no secondary finding (fat stranding, diameter >13mm, abscess, cecal wall thickening, periappendiceal gas, simple fluid collection, appendicolith, and phlegmon) with a clinically reliable sensitivity or specificity to predict perforated appendicitis. Surgeon׳s report of perforation was consistent with the pathology report of perforation in only 28% of cases. The usefulness of a CT for determining perforation in acute appendicitis is limited, and methods to improve precision in identifying patients with complicated appendicitis should be explored as this may help for improving risk prediction for failure of treatment with antibiotic therapy and help guide patients and providers in shared decision-making for treatment options. Copyright © 2017 Elsevier Inc. All rights reserved.

New diluted ferromagnetic semiconductor with Curie temperature up to 180 K and isostructural to the '122' iron-based superconductors.

PubMed

Zhao, K; Deng, Z; Wang, X C; Han, W; Zhu, J L; Li, X; Liu, Q Q; Yu, R C; Goko, T; Frandsen, B; Liu, Lian; Ning, Fanlong; Uemura, Y J; Dabkowska, H; Luke, G M; Luetkens, H; Morenzoni, E; Dunsiger, S R; Senyshyn, A; Böni, P; Jin, C Q

2013-01-01

Diluted magnetic semiconductors have received much attention due to their potential applications for spintronics devices. A prototypical system (Ga,Mn)As has been widely studied since the 1990s. The simultaneous spin and charge doping via hetero-valent (Ga(3+),Mn(2+)) substitution, however, resulted in severely limited solubility without availability of bulk specimens. Here we report the synthesis of a new diluted magnetic semiconductor (Ba(1-x)K(x))(Zn(1-y)Mn(y))(2)As(2), which is isostructural to the 122 iron-based superconductors with the tetragonal ThCr(2)Si(2) (122) structure. Holes are doped via (Ba(2+), K(1+)) replacements, while spins via isovalent (Zn(2+),Mn(2+)) substitutions. Bulk samples with x=0.1-0.3 and y=0.05-0.15 exhibit ferromagnetic order with T(C) up to 180 K, which is comparable to the highest T(C) for (Ga,Mn)As and significantly enhanced from T(C) up to 50 K of the '111'-based Li(Zn,Mn)As. Moreover, ferromagnetic (Ba,K)(Zn,Mn)(2)As(2) shares the same 122 crystal structure with semiconducting BaZn(2)As(2), antiferromagnetic BaMn(2)As(2) and superconducting (Ba,K)Fe(2)As(2), which makes them promising for the development of multilayer functional devices.

The first perforating branch of the deep femoral artery: A reliable recipient vessel for vascularized fibular grafts: An anatomical study.

PubMed

Sur, Yoo Joon; Morsy, Mohamed; Mohan, Anita T; Zhu, Lin; Lachman, Nirusha; Saint-Cyr, Michel

2016-03-01

Although the perforating branches of the deep femoral artery have been introduced as recipient vessels for vascularized fibular grafts in the treatment of osteonecrosis of the femoral head, comprehensive knowledge of the related anatomy is deficient. The aims of this study were to provide detailed anatomical data for the perforating branches of the deep femoral artery and validate their usefulness as recipient vessels for vascularized fibular grafts. Anatomical dissection was performed on 11 fresh human cadaveric lower extremities. The number, locations, and diameters of the perforating branches were documented. The topographic relationships with the vastus ridge and the tendinous insertion of the gluteus maximus were clarified. The diameters of the perforating branches were compared with those of the ascending branch of the lateral circumflex femoral and the peroneal arteries. The mean number of perforating branches was 3.5. The mean distances from the vastus ridge to the first, second, and third perforating branches were 8.1, 13.7, and 20.4 cm, respectively. The first perforating branch was always located medial to the tendinous insertion of the gluteus maximus, whereas the second perforating branch was always located distal to the gluteus maximus. The mean diameters of the first, second, third, and fourth perforating branches were 3.1, 2.3, 1.6, and 1.2 mm, respectively. The mean diameters of the ascending branch of the lateral circumflex femoral and the peroneal arteries were 2.0 and 3.6 mm, respectively. The first perforating branch of the deep femoral artery is an appropriate alternative recipient vessel for vascularized fibular grafts in the treatment of osteonecrosis of the femoral head. It has a very consistent anatomy with a suitable location and diameter for anastomosis of the peroneal artery. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

A comparison of the surgical mortality due to colorectal perforation at different hospitals with data from 10,090 cases in the Japanese National Clinical Database.

PubMed

Ohki, Takeshi; Yamamoto, Masakazu; Miyata, Hiroaki; Sato, Yasuto; Saida, Yoshihisa; Morimoto, Tsuyoshi; Konno, Hiroyuki; Seto, Yasuyuki; Hirata, Koichi

2017-01-01

Colorectal perforation has a high rate of mortality. We compared the incidence and fatality rates of colorectal perforation among different hospitals in Japan using data from the nationwide surgical database.Patients were registered in the National Clinical Database (NCD) between January 1st, 2011 and December 31st, 2013. Patients with colorectal perforation were identified from surgery records by examining if acute diffuse peritonitis (ADP) and diseases associated with a high probability of colorectal perforation were noted. The primary outcome measures included the 30-day postsurgery mortality and surgical mortality of colorectal perforation. We analyzed differences in the observed-to-expected mortality (O/E) ratio between the two groups of hospitals, that is, specialized and non-specialized, using the logistic regression analysis forward selection method.There were 10,090 cases of disease-induced colorectal perforation during the study period. The annual average postoperative fatality rate was 11.36%. There were 3884 patients in the specialized hospital group and 6206 in the non-specialized hospital group. The O/E ratio (0.9106) was significantly lower in the specialized hospital group than in the non-specialized hospital group (1.0704). The experience level of hospitals in treating cases of colorectal perforation negatively correlated with the O/E ratio.We conducted the first study investigating differences among hospitals with respect to their fatality rate of colorectal perforation on the basis of data from a nationwide database. Our data suggest that patients with colorectal perforation should choose to be treated at a specialized hospital or a hospital that treats five or more cases of colorectal perforation per year. The results of this study indicate that specialized hospitals may provide higher quality medical care, which in turn proves that government policy on healthcare is effective at improving the medical system in Japan.

Gallbladder perforation: case series and systematic review.

PubMed

Date, Ravindra S; Thrumurthy, Sri G; Whiteside, Sigrid; Umer, Mohammed A; Pursnani, Kishore G; Ward, Jeremy B; Mughal, M Muntzer

2012-01-01

Gallbladder perforation is a serious complication of acute cholecystitis. Its management has evolved considerably since its classification by Niemeier in 1934. This review summarises the evidence surrounding the natural progression of this condition and potential problems with Niemeier's classification, and proposes a management algorithm for the more complex type II perforation. Data from a retrospective case series and a systematic review were combined. The case series included all patients with gallbladder perforations from 2004 to 2008 at a British teaching hospital. The systematic review searched for gallbladder perforation using the MEDLINE, Embase, Web of Science and Cochrane Library (2011 Issue 4) databases, as well as recent conference abstracts. The outcome data were analysed using SPSS version 15. No adjustments were made for multiple testing. 198 patients (including 19 patients from the present series) with a mean age of 62.1+/-9.7 years and male gender proportion of 55.4% (range 33.3-76.7%) were included. The most common gallbladder perforations were type II (median 46.2%, range 7.4-83.3%), followed by type I (median 40.6%, range 16.7-70.0%) and type III (median 10.1%, range 0-48.1%). Perforation was associated with cholelithiasis in 86.6% (range 78.9-90.6%) of patients, and the overall median mortality rate was 10.8% (range 0-12.5%). Male gender was weakly associated with mortality (p = 0.089) but age (p = 0.877) and cholelithiasis (p = 0.425) were not. Mortality did not vary significantly with perforation type. Gallbladder perforation should be reported according to the original Neimeier's classification to avoid heterogeneity in data (e.g. varying rates of perforation types). The algorithm proposed in this study aims to guide the management of complex type II gallbladder perforations to minimise subsequent morbidity and mortality. Copyright © 2012 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Perforated marginal ulcers after laparoscopic gastric bypass.

PubMed

Felix, Edward L; Kettelle, John; Mobley, Elijah; Swartz, Daniel

2008-10-01

Perforated marginal ulcer (PMU) after laparoscopic Roux-en-Y gastric bypass (LRYGB) is a serious complication, but its incidence and etiology have rarely been investigated. Therefore, a retrospective review of all patients undergoing LRYGB at the authors' center was conducted to determine the incidence of PMU and whether any causative factors were present. A prospectively kept database of all patients at the authors' bariatric center was retrospectively reviewed. The complete records of patients with a PMU were examined individually for accuracy and analyzed for treatment, outcome, and possible underlying causes of the marginal perforation. Between April 1999 and August 2007, 1% of the patients (35/3,430) undergoing laparoscopic gastric bypass experienced one or more perforated marginal ulcers 3 to 70 months (median, 18 months) after LRYGB. The patients with and without perforation were not significantly different in terms of mean age (37 vs 41 years), weight (286 vs 287 lb), body mass index (BMI) (46 vs 47), or female gender (89% vs 83%). Of the patients with perforations, 2 (6%) were taking steroids, 10 (29%) were receiving nonsteroidal antiinflammatory drugs (NSAIDs) at the time of the perforation, 18 (51%) were actively smoking, and 6 of the smokers also were taking NSAIDs. Eleven of the patients (31%) who perforated did not have at least one of these possible risk factors, but 4 (36%) of the 11 patients in this group had been treated after bypass for a marginal ulcer. Only 7 (20%) of the 35 patients who had laparoscopic bypass, or 7 (0.2%) in the entire group of 3,430 patients, perforated without any warning. There were no deaths, but three patients reperforated. The incidence of a marginal ulcer perforating after LRYGB was significant (>1%) and appeared to be related to smoking or the use of NSAIDs or steroids. Because only 0.2% of all patients acutely perforated without some risk factor or warning, long-term ulcer prophylaxis or treatment may be necessary for only a select group of high-risk patients.

Influence of national centralization of oesophagogastric cancer on management and clinical outcome from emergency upper gastrointestinal conditions.

PubMed

Markar, S R; Mackenzie, H; Wiggins, T; Askari, A; Karthikesalingam, A; Faiz, O; Griffin, S M; Birkmeyer, J D; Hanna, G B

2018-01-01

In England in 2001 oesophagogastric cancer surgery was centralized. The aim of this study was to evaluate whether centralization of oesophagogastric cancer to high-volume centres has had an effect on mortality from different emergency upper gastrointestinal conditions. The Hospital Episode Statistics database was used to identify patients admitted to hospitals in England (1997-2012). The influence of oesophagogastric high-volume cancer centre status (20 or more resections per year) on 30- and 90-day mortality from oesophageal perforation, paraoesophageal hernia and perforated peptic ulcer was analysed. Over the study interval, 3707, 12 441 and 56 822 patients with oesophageal perforation, paraoesophageal hernia and perforated peptic ulcer respectively were included. There was a passive centralization to high-volume cancer centres for oesophageal perforation (26·9 per cent increase), paraoesophageal hernia (19·5 per cent increase) and perforated peptic ulcer (23·0 per cent increase). Management of oesophageal perforation in high-volume centres was associated with a reduction in 30-day (HR 0·58, 95 per cent c.i. 0·45 to 0·74) and 90-day (HR 0·62, 0·49 to 0·77) mortality. High-volume cancer centre status did not affect mortality from paraoesophageal hernia or perforated peptic ulcer. Annual emergency admission volume thresholds at which mortality improved were observed for oesophageal perforation (5 patients) and paraoesophageal hernia (11). Following centralization, the proportion of patients managed in high-volume cancer centres that reached this volume threshold was 88·0 per cent for oesophageal perforation, but only 30·3 per cent for paraoesophageal hernia. Centralization of low incidence conditions such as oesophageal perforation to high-volume cancer centres provides a greater level of expertise and ultimately reduces mortality. © 2017 BJS Society Ltd Published by John Wiley & Sons Ltd.

Pedicle Perforation While Inserting Screws Using O-Arm Navigation During Surgery for Adolescent Idiopathic Scoliosis: Risk Factors and Effect of Insertion Order.

PubMed

Oba, Hiroki; Ebata, Shigeto; Takahashi, Jun; Koyama, Kensuke; Uehara, Masashi; Kato, Hiroyuki; Haro, Hirotaka; Ohba, Tetsuro

2018-06-11

Observational cohort study. To compare the rate of pedicle perforation while inserting screws (PS) using O-arm navigation during surgery for scoliosis with that reported previously, and to determine risk factors specific to O-arm navigation. O-arm navigation provides intraoperative three-dimensional fluoroscopic imaging with an image quality similar to that of computed tomography. Surgeons have started using O-arm navigation in treatment of adolescent idiopathic sclerosis (AIS). However, there are few reports of the perforation rate when using O-arm navigation to insert pedicle screws for AIS. To our knowledge, no information has been published regarding risk factors for pedicle perforation by PS when using O-arm navigation during surgery for AIS. We retrospectively reviewed the cases of 23 consecutive patients with AIS (all female; mean age 15.4 years, range 12-19 years) who had all undergone PS fixation under O-arm navigation. There were 11 major pedicle perforations (Grade 2 or 3) by the 404 screws (2.7%). For both Grade 1-3 and Grade 2 or 3 perforations, the pedicle perforation rate by the ninth or subsequent screws was significantly higher than that for the other two groups (screws 1-4, 5-8) (P < 0.01). Grade 1-3, Grades 2 or 3, and Grade 3 perforation rates after a previous perforation were significantly higher than those in patients without a previous perforation (P < 0.01). The rate of screw deviation can increase significantly to 12.2% after insertion of 8. The rate of major perforation of pedicles after inserting PS using O-arm navigation during surgery for AIS is relatively low. However, we recommend caution using intraoperative navigation after inserting 8 pedicle screws because after this, the trajectory deviation rate can increase significantly. 3.

Perforator flap based on the third perforator of the profunda femoris artery (PFA)-assisted closure of the free vertical posteromedial thigh (vPMT) flap donor site.

PubMed

Scaglioni, Mario F; Barth, Andrè A; Chen, Yen-Chou

2018-06-19

The primary closure of the vertical posteromedial thigh (vPMT) free flap donor site is very important to minimize donor site morbidity and maximize cosmetic appearance. However, sometimes due to the dimension of the defect, a vPMT flap is wider than the 8-10 cm requirement. The authors report their experience with the third perforator of the profunda femoris artery (PFA) during the vPMT free flap donor-site closure. Between January 2016 and December 2017, 5 patients underwent reconstruction of lower extremity (2 pts.) and head and neck (3 pts.) area with the free vPMT flaps. Attempts to close the vPMT free flap donor site directly failed due to the flaps' width (average: 11 cm) and pedicled perforator flaps based on the third perforator of the PFA at the distal thigh were harvested to close the defect primary without the use of a skin graft. The size of perforator flap based on 3rd perforator of PFA was on average 6 cm × 4 cm (ranged: 4-8 cm × 3-6 cm). In all patients, the third perforator of the PFA was identified and the perforator diameter was on average 2.0 mm (range, 1.8-2.2 mm). All perforators were musculocutaneous and single. The dimensions of the flaps were on average 6 cm × 4 cm (range: 4 to 8 cm × 3 to 6 cm). All flaps healed uneventfully without complications and the patients were satisfied with cosmetic and functional results at 6 months follow-up. The third perforator of the PFA may be an option to ensure primary closure of the PMT flap donor site, when a larger flap for reconstruction is needed with subsequent impossibility to achieve primary closure of the donor site. © 2018 Wiley Periodicals, Inc.

Microvascular anatomy of the cerebellar parafloccular perforating space.

PubMed

Sosa, Pablo; Dujovny, Manuel; Onyekachi, Ibe; Sockwell, Noressia; Cremaschi, Fabián; Savastano, Luis E

2016-02-01

The cerebellopontine angle is a common site for tumor growth and vascular pathologies requiring surgical manipulations that jeopardize cranial nerve integrity and cerebellar and brainstem perfusion. To date, a detailed study of vessels perforating the cisternal surface of the middle cerebellar peduncle-namely, the paraflocculus or parafloccular perforating space-has yet to be published. In this report, the perforating vessels of the anterior inferior cerebellar artery (AICA) in the parafloccular space, or on the cisternal surface of the middle cerebellar peduncle, are described to elucidate their relevance pertaining to microsurgery and the different pathologies that occur at the cerebellopontine angle. Fourteen cadaveric cerebellopontine cisterns (CPCs) were studied. Anatomical dissections and analysis of the perforating arteries of the AICA and posterior inferior cerebellar artery at the parafloccular space were recorded using direct visualization by surgical microscope, optical histology, and scanning electron microscope. A comprehensive review of the English-language and Spanish-language literature was also performed, and findings related to anatomy, histology, physiology, neurology, neuroradiology, microsurgery, and endovascular surgery pertaining to the cerebellar flocculus or parafloccular spaces are summarized. A total of 298 perforating arteries were found in the dissected specimens, with a minimum of 15 to a maximum of 26 vessels per parafloccular perforating space. The average outer diameter of the cisternal portion of the perforating arteries was 0.11 ± 0.042 mm (mean ± SD) and the average length was 2.84 ± 1.2 mm. Detailed schematics and the surgical anatomy of the perforating vessels at the CPC and their clinical relevance are reported. The parafloccular space is a key entry point for many perforating vessels toward the middle cerebellar peduncle and lateral brainstem, and it must be respected and protected during surgical approaches to the cerebellopontine angle.

Evaluation of three-dimensional computed tomography processing for deep inferior epigastric perforator flap breast reconstruction.

PubMed

Teoh, Raymond; Johnson, Raleigh F; Nishino, Thomas K; Ethridge, Richard T

2007-01-01

The deep inferior epigastric perforator flap procedure has become a popular alternative for women who require breast reconstruction. One of the difficulties with this procedure is identifying perforator arteries large enough to ensure that the harvested tissue is well vascularized. Current techniques involve imaging the perforator arteries with computed tomography (CT) to produce a grid mapping the locations of the perforator arteries relative to the umbilicus. To compare the time it takes to produce a map of the perforators using either two-dimensional (2D) or three-dimensional (3D) CT, and to see whether there is a benefit in using a 3D model. Patient CT abdomen and pelvis scans were acquired from a GE 64-slice scanner. CT image processing was performed with the GE 3D Advantage Workstation v4.2 software. Maps of the perforators were generated both as 2D and 3D representations. Perforators within a region 5 cm rostral and 7 cm caudal to the umbilicus were measured and the times to perform these measurements using both 2D and 3D images were recorded by a stopwatch. Although the 3D method took longer than the 2D method (mean [+/- SD] time 1:51+/-0:35 min versus 1:08+/-0:16 min per perforator artery, respectively), producing a 3D image provides much more information than the 2D images alone. Additionally, an actual-sized 3D image can be printed out, removing the need to make measurements and producing a grid. Although it took less time to create a grid of the perforators using 2D axial CT scans, the 3D reconstruction of the abdomen allows the plastic surgeons to better visualize the patient's anatomy and has definite clinical utility.

Gastro-intestinal tract perforation in neonates.

PubMed

Kuremu, R T; Hadley, G P; Wiersma, R

2003-09-01

Gastro-intestinal tract (GIT) perforation in neonates is a serious problem associated with high mortality due to resulting sepsis. Co-morbid factors, eg. prematurity, respiratory problems, low birth weight, and nutritional factors, negatively affect the outcome. To review the management outcome of gastro-intestinal tract perforation in neonates in KwaZulu-Natal and identify factors that require attention for better survival of neonates with GIT perforation. Retrospective study of consecutive complete data sets of patients presenting with a diagnosis of GIT perforation. Department of Paediatric Surgery, Nelson R. Mandela School of Medicine, University of Natal, Durban, South Africa. Fifty four neonates treated for gastro-intestinal tract perforation between January 1998 and January 2003. Morbidity as determined by complications and mortality. More males (69%) were affected than females (31%). The median birth weight was 2.3 kg and median age at presentation was four days. Eighty nine percent were referred from peripheral hospitals. Abdominal distension was the leading symptom and sign (74%). Co-morbid factors were present in 89%, with prematurity as the leading factor (52%). Necrotising enterocolitis (NEC) was the main cause of perforation (33%) and the terminal ileum was the most common site. Most (56%) were treated by excision and primary repair of perforations. Sepsis was the leading complication (44%) and major cause of death (72%). Mortality was highest (56%) in perforations due to other primary pathology followed by NEC (53%). Overall mortality was 46%. It is essential to prevent secondary perforations by early recognition and management of primary pathology. Management of pneumoperitoneum in neonates with respiratory difficulties should be included in resuscitation before transfer. Rectal temperature monitoring and herbal enemas should be strongly discouraged.

Evaluation of dynamic infrared thermography as an alternative to CT angiography for perforator mapping in breast reconstruction: a clinical study.

PubMed

Weum, Sven; Mercer, James B; de Weerd, Louis

2016-07-15

The current gold standard for preoperative perforator mapping in breast reconstruction with a DIEP flap is CT angiography (CTA). Dynamic infrared thermography (DIRT) is an imaging method that does not require ionizing radiation or contrast injection. We evaluated if DIRT could be an alternative to CTA in perforator mapping. Twenty-five patients scheduled for secondary breast reconstruction with a DIEP flap were included. Preoperatively, the lower abdomen was examined with hand-held Doppler, DIRT and CTA. Arterial Doppler sound locations were marked on the skin. DIRT examination involved rewarming of the abdominal skin after a mild cold challenge. The locations of hot spots on DIRT were compared with the arterial Doppler sound locations. The rate and pattern of rewarming of the hot spots were analyzed. Multiplanar CT reconstructions were used to see if hot spots were related to perforators on CTA. All flaps were based on the perforator selected with DIRT and the surgical outcome was analyzed. First appearing hot spots were always associated with arterial Doppler sounds and clearly visible perforators on CTA. The hot spots on DIRT images were always slightly laterally located in relation to the exit points of the associated perforators through the rectus abdominis fascia on CTA. Some periumbilical perforators were not associated with hot spots and showed communication with the superficial inferior epigastric vein on CTA. The selected perforators adequately perfused all flaps. This study confirms that perforators selected with DIRT have arterial Doppler sound, are clearly visible on CTA and provide adequate perfusion for DIEP breast reconstruction. Retrospectively registered at ClinicalTrials.gov with identifier NCT02806518 .

The use of a surgical assist device to reduce glove perforations in postdelivery vaginal repair: a randomized controlled trial.

PubMed

Bebbington, M W; Treissman, M J

1996-10-01

Our purpose was to compare the effectiveness of a surgical assist device, SutureMate, to decrease glove perforations during postdelivery vaginal repair. This was a prospective randomized trial. After delivery surgeons who needed to perform vaginal repair were randomized to use the surgical assist device or to perform the repair in the usual fashion. After the repair, gloves were collected and the operator was asked to complete a standardized data form that was submitted with the gloves. The gloves were tested for perforations within 24 hours by the Food and Drug Administration-approved hydrosufflation technique. Comparisons were made with chi(2) statistics with p < 0.01 taken as being statistically significant with the use of a Bonferoni adjustment for multiple comparisons. A total of 476 glove sets were evaluated. The use of the surgical assist device significantly reduced the overall glove perforation rate from 28.3% in the control arm to 8.4% in the study arm (p = 0.0001). Rates of perforation varied with level of training and expertise but fell in all groups that used the device. Family physicians had the highest perforation rate in the control arm and benefited most from the device. A total of 76% of perforations were located in the thumb, index, and second fingers of the nondominant hand. Perforations were recognized in only 16% of the glove sets. The level of satisfaction with the device was mixed, but overall 50% of operators indicated that they were either satisfied or very satisfied with the device. The rate of glove perforation in postdelivery vaginal repair is high. The surgical assist device significantly reduced the rate of glove perforations.

Incidence of Cardiac Perforation With Conventional and With Leadless Pacemaker Systems: A Systematic Review and Meta-Analysis.

PubMed

Vamos, Mate; Erath, Julia W; Benz, Alexander P; Bari, Zsolt; Duray, Gabor Z; Hohnloser, Stefan H

2017-03-01

Two leadless pacemaker (PM) systems were recently developed to avoid pocket- and lead-related complications. As leadless PMs are implanted with a large delivery catheter, cardiac perforation remains a major safety concern. We aimed to provide a literature review on incidence of cardiac perforation with conventional and with leadless PM systems. A systematic review over the last 25 years for studies reporting data on PM lead perforation was performed. Findings were synthesized descriptively. Where control groups were available, data were meta-analyzed to identify important clinical risk factors. A total of 28 studies comprising 60,744 patients undergoing conventional PM implantation were analyzed. The incidence of lead perforation ranged from 0% to 6.37% (mean 0.82%, weighted mean 0.31%, median of 0.40%). There was no significant difference in perforation risk between atrial and ventricular electrodes (POR 0.72, 95% confidence interval [CI], 0.28-1.87, P = 0.50) and between MRI conditional and conventional leads (POR 5.93, 95% CI, 0.72-48.76, P = 0.10). The use of active fixation leads (POR 4.25, 95% CI, 1.00-17.95, P = 0.05) and utilization of DDD versus VVI PM systems (POR 3.50, 95% CI, 1.48-8.28, P < 0.01) were associated with higher rates of perforation. In the 2 leadless PM studies, the incidence of cardiac perforation was 1.52% for each. PM lead perforation rates vary in individual studies with an overall low incidence. Leadless PMs seem to be associated with a slightly higher perforation risk, most likely reflecting a learning curve effect of this novel technology. © 2016 Wiley Periodicals, Inc.

Perforated Duodenal Ulcer in High Risk Patients: Is Percutaneous Drainage Justified?

PubMed Central

Saber, Aly; Gad, Mohammad A; Ellabban, Gouda M

2012-01-01

Background: Conservative treatment was recommended as the treatment of choice in perforated acute peptic ulcer. Here, we adjunct percutaneous peritoneal drainage with nonoperative conservative treatment in high risk elderly patients with perforated duodenal ulcer. Aim: The work was to study the efficacy of percutaneous peritoneal drainage under local anesthesia supported by conservative measures in high risk elderly patients, according to the American Society of Anesthesiologists grading, with perforated duodenal ulcer. Patients and Methods: Twenty four high risk patients with age >65 years having associated medical illness with evidence of perforated duodenal ulcer. Results: The overall morbidity and mortality were comparable with those treated by conservative measures alone. Conclusion: In high risk patients with perforated peptic ulcer and established peritonitis, percutaneous peritoneal drainage under local anesthesia seems to be effective with least operative trauma and mortality rate. PMID:22393546

Perforated peptic ulcer in Tikur Anbessa Hospital: a review of 74 cases.

PubMed

Ersumo, Tessema; W/Meskel, Yidnekachew; Kotisso, Berhanu

2005-01-01

Little is known on the pattern of perforated peptic ulcer in Ethiopia. To evaluate the early, outcome of management, a five-year retrospective analysis of 74 operated cases of perforated peptic ulcer was undertaken. Perforated peptic ulcer accounted for 3.4% of the adult emergency surgical procedures. The mean age was 32.6 years, with a male to female ratio of 7.2 to 1.0. Fifty-six percent of the cases were unmarried. In nearly 22.0% of the patients, no previous history of peptic ulcer disease was documented. Delay in diagnosis was noted in 95% of the cases. Most patients had duodenal ulcer perforation, and about 78% had purulent peritonitis at laparotomy. Fourteen died in hospital. Early presentation of patients to surgical care facilities may reduce morbidity and mortality in cases of peptic ulcer perforation.

Boerhaave's syndrome in a patient with an upside down stomach: A case report.

PubMed

Saito, Shin; Hosoya, Yoshinori; Kurashina, Kentaro; Matsumoto, Shiro; Kanamaru, Rihito; Ui, Takashi; Haruta, Hidenori; Kitayama, Joji; Lefor, Alan K; Sata, Naohiro

2016-01-01

Spontaneous esophageal perforation, or Boerhaave's syndrome, is a life-threating condition which usually requires emergent surgery. An upside down stomach is defined as a gastric volvulus in a huge supradiaphragmatic sac. In general, this condition can result in ischemia and perforation of the stomach. This is the first report of a patient with Boerhaave's syndrome and an upside down stomach. A 79-year-old woman presented with sudden epigastric pain following hematemesis. Evaluation of the patient showed both an esophageal perforation and an upside down stomach. Surgical drainage and irrigation of the mediastinum and pleural cavities were undertaken emergently. Due to the concurrent gastric volvulus, a gastrostomy was placed to fix and decompress the stomach. The patient had an uneventful hospital course and was discharged. Boerhaave's syndrome is a rare but severe complication caused by excessive vomiting, due to a sudden elevation in intraluminal esophageal pressure resulting in esophageal perforation. Acute gastric volvulus can result in ischemia and perforation of the stomach, but has not previously been reported with esophageal perforation. The most likely mechanism associating an upside down stomach with Boerhaave's syndrome is acute gastric outlet obstruction resulting in vomiting, and subsequent esophageal perforation. Perforation of the esophagus as well as perforation of the stomach must be considered in patients with an upside down stomach although both upside down stomach and Boerhaave's syndrome are rare clinical entities. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Preoperative factors influencing mortality and morbidity in peptic ulcer perforation.

PubMed

Sivaram, P; Sreekumar, A

2018-04-01

Perforated peptic ulcer is one of the most common surgical emergencies worldwide. With the improvement in medical therapy for peptic ulcers, the number of elective surgical procedures has come down. However, the incidence of perforated peptic ulcer is still increasing and remains as a substantial health problem with significant postoperative morbidity and mortality. This study aimed to find out the association between various preoperative and intraoperative factors with the postoperative mortality and morbidity in patients operated for peptic ulcer perforation. This prospective observational study had a time based sample of 101 perforation peritonitis cases admitted to the surgical wards of a tertiary care center from February 2015 to January 2016 who underwent laparotomy, diagnosed to have peptic ulcer perforation and underwent simple closure with an omental patch. Data regarding age, gender, presenting complaints, time elapsed from the onset of symptoms to surgery, physical examination findings, comorbid diseases, laboratory and imaging findings, intraoperative findings, length of hospital stay, postoperative morbidity, and mortality were recorded and analyzed. Female gender, older age group, perforation surgery interval more than 36 h, and size of perforation more than 1 cm 2 were found to be significant factors influencing postoperative mortality and morbidity. Postoperative morbidity was also associated with comorbid diseases. Abnormal renal function on presentation was identified as an additional risk factor for postoperative morbidity and longer hospital stay. An understanding of these factors, identification of patients at risk and early intervention can help in reducing the postoperative morbidity and mortality in peptic ulcer perforation.

A Study of 4-level DC-DC Boost Inverter with Passive Component Reduction Consideration

NASA Astrophysics Data System (ADS)

Kasiran, A. N.; Ponniran, A.; Harimon, M. A.; Hamzah, H. H.

2018-04-01

This study is to analyze design principles of boost inductor and capacitor used in the 4-level DC-DC boost converter to realize size reduction of passive component referring to their attributes. The important feature of this circuit is that most of the boost-up energy is transferred from the capacitor-clamped to the output side which the small inductance can be used at the input side. The inductance of the boost inductor is designed by referring the inductor current ripple. On the other hand, the capacitance of the capacitor-clamped is designed by considering voltage stress on semiconductor devices and also the used switching frequency. Besides that, according to the design specifications, the required inductance in 4-level DC-DC boost converter is decreased compared to a conventional conventional DC-DC boost converter. Meanwhile, voltage stress on semiconductor device is depending on the maximum voltage ripple of the capacitor-clamped. A 50 W 4-level DC-DC boost converter prototype has been constructed. The results show that the inductor current ripple was 1.15 A when the inductors, 1 mH and 0.11 mH were used in the conventional and 4-level DC-DC boost converters, respectively. Thus, based on the experimental results, it shows that the reduction of passive components by referring to their attributes in 4-level DC-DC boost converter is achieved. Moreover, the decreasing of voltage stress on the semiconductor devices is an advantage for the selection of low ON-resistance of the devices which will contribute to the reduction of the semiconductor conduction loss. The integration result of boost converter and H-bridge inverter is also shown.

Perforations and angulations of 324 cervical medial cortical pedicle screws: a possible guide to avoid lateral perforations with use of pedicle screws in lower cervical spine.

PubMed

Mahesh, Bijjawara; Upendra, Bidre; Vijay, Sekharappa; Arun, Kumar; Srinivasa, Reddy

2017-03-01

More than half of the perforations reported with usage of cervical pedicle screws (CPS) are lateral perforations, endangering the vertebral artery. The medial cortical pedicle screw (MCPS) technique with partial drilling of the medial cortex shifts the trajectory of pedicle screws medially, decreasing the lateral perforations. To evaluate the decrease in lateral perforations of CPS with use of MCPS technique, in relation to medial angulation. Retrospective analysis and technical report of the MCPS technique and its safety. A total of 58 patients operated on between December 2011 and May 2015 with insertion of pedicle screws from C3 to C7 were included in the study. Axial reconstructed computed tomography (CT) scan images of the inserted screws were evaluated for placement, perforations, and transverse plane angulations using the Surgimap software (Surgimap Spine 1.1.2.271 Intl. 2009 Nemaris LLC). The angulations of screws were analyzed by the type and level of placement through unpaired t test and analysis of variance test. A total of 58 patients operated on between December 2011 and May 2015 with insertion of pedicle screws from C3 to C7 were included in the study. There were 49 males and 9 females. Thirty-seven patients had cervical trauma, 17 had cervical spondylotic myelopathy, two had tumors, and two had ankylosing spondylitis. The average age was 49 years (range 18 to 80 years). The screws were inserted using the MCPS technique. All patients underwent postoperative CT scans with GE Optima CT540 16 slice CT scanner (GE Healthcare Chalfont St. Giles, Buckinghamshire, UK). Axial reconstructed images along the axis of the inserted screws were evaluated for placement and perforations. Further, all the screws were evaluated for transverse plane angulations using the Surgimap software. The angulations of screw were analyzed by the type and level of placement through unpaired t test and analysis of variance test. No funds were received by any of the authors for the purpose of the present study. A total of 324 screws were assessed with postoperative CT scans. Two hundred fifty-six were found to be placed within the pedicle and 68 (20.98%) screws were found to have perforations. Forty screws (12.34%) had grade I medial perforations, 14 screws (4.32%) had grade I lateral perforations, 10 screws (3.08%) had grade II medial perforations, and 4 screws (1.23%) had grade IIlateral perforations. The average angulation of the nonperforated screws (n=256) was 28.6° (43°-17°), that of laterally perforated screws was 20.33° (13°-24°), and that of the medially perforated screws was 34.94° (45°-20°). On statistical analysis with each series, the 99% CI range for the in-screw angles was 27.91° to 29.34°; for the laterally perforated screw series, it was 18.42° to 22.23°; and that for the medially perforated screw series was 32.97° to 36.9°. The MCPS technique represents a shift in the concept of placement of CPS from the cancellous core to the medial cortex, avoiding screw deflection laterally by the thick proximal medial cortex. The present study shows that the lateral perforations can be consistently avoided, with a medial angulation of more than 27.91°, which is the primary concern with the use of pedicle screws in lower cervical spine. Further, the MCPS technique reduces the lateral perforations at a lesser insertion angle, which is technically desirable. Copyright © 2016 Elsevier Inc. All rights reserved.

Laparoscopic removal of an intra-abdominal intrauterine device: case and systematic review.

PubMed

Gill, Richdeep S; Mok, Dereck; Hudson, Matthew; Shi, Xinzhe; Birch, Daniel W; Karmali, Shahzeer

2012-01-01

Uterine perforation by intrauterine devices (IUDs) is a rare but well recognized complication. In the past, the presence of adhesions and perforation of viscera often resulted in the need for a laparotomy to remove the IUD. However, advances in laparoscopic technique have allowed surgeons to safely retrieve perforated IUDs. In this review, we analyze uterine perforation by an IUD and assess laparoscopic vs. open methods for removal of a perforated IUD. A systematic search strategy was applied to several electronic bibliographic databases: Medline/Pubmed, Embase, Cochrane Library, and OCLC PapersFirst. Key words used were IUD, laparoscopy, and uterine perforation. One hundred seventy-nine cases of attempted laparoscopic removal of perforated IUDs were identified in the English literature between 1970 and 2009. Patient age ranged from 17 to 49 years. Diagnostic laparoscopy was performed in all 179 cases reported. Laparoscopic removal of perforated IUDs was achieved successfully in 64.2% (115/179) of cases. This systematic review highlights how advances in laparoscopic technique and skill have allowed surgeons to safely retrieve IUDs without laparotomy. We recommend an attempt at laparoscopic removal as first-line treatment in symptomatic patients and as a reasonable treatment option in asymptomatic patients. Copyright © 2012 Elsevier Inc. All rights reserved.

Influence of operating microscope in the sealing of cervical perforations.

PubMed

Schmidt, Bruna Schwingel; Zaccara, Ivana Maria; Reis Só, Marcus Vinícius; Kuga, Milton Carlos; Palma-Dibb, Regina Guenka; Kopper, Patrícia Maria Poli

2016-01-01

Accidental root canal perforations are among the main complications of endodontic treatment. This study evaluated the influence of operating microscope (OM) in the marginal adaptation of mineral trioxide aggregate (MTA) (Angelus(®)) and glass ionomer (Vitremer) inserted into cervical perforations. Perforations were made in the cervical third of the buccal wall of the root canal in mandibular incisors. Next, the teeth were divided into four groups (N = 10): MG - MTA without OM; VG - Vitremer without OM; MOMG - MTA with OM; VOMG - Vitremer with OM. The perforations were sealed according to the group and the teeth were prepared for analysis by confocal laser scanning microscope. Images of perforation region (1,024×) were made and the gap presented by the materials was measured using the Image J program. LEXT OLS4100 three dimensional (3D) measuring laser microscope measured the volumetric misfit. Data of gap were analyzed by Kruskal-Wallis and Dunn's tests. Analysis of variance (ANOVA) and Tukey's tests compared the volumetric misfits. The results showed lower volume and gap in the interface dentin/material in VOMG compared to the other groups (P < 0.05). The use of OM improved the quality of cervical perforations sealed with Vitremer, being indicated in clinical situations of iatrogenic cervical perforations.

Assessment of Tissue Perfusion Following Conventional Liposuction of Perforator-Based Abdominal Flaps

PubMed Central

Saçak, Bülent; Yalçın, Doğuş; Pilancı, Özgür; Tuncer, Fatma Betül; Çelebiler, Özhan

2017-01-01

Background The effect of liposuction on the perforators of the lower abdominal wall has been investigated in several studies. There are controversial results in the literature that have primarily demonstrated the number and patency of the perforators. The aim of this study was to determine the effect of liposuction on the perfusion of perforator-based abdominal flaps using a combined laser–Doppler spectrophotometer (O2C, Oxygen to See, LEA Medizintechnik). Methods Nine female patients undergoing classical abdominoplasty were included in the study. Perforators and the perfusion zones of the deep inferior epigastric artery flap were marked on the patient's abdominal wall. Flap perfusion was quantitatively assessed by measuring blood flow, velocity, capillary oxygen saturation, and relative amount of hemoglobin for each zone preoperatively, after tumescent solution infiltration, following elevation of the flap on a single perforator, and after deep and superficial liposuction, respectively. Results The measurements taken after elevation of the flap were not significantly different than measurements taken after the liposuction procedures. Conclusions The liposuction procedure does not significantly alter the perfusion of perforator-based abdominal flaps in the early period. The abdominal tissue discarded in a classic abdominoplasty operation can be raised as a perforator flap and has been demonstrated to be a unique model for clinical research. PMID:28352599

Small bowel perforation without tumor recurrence after radiotherapy for cervical carcinoma: report of seven cases.

PubMed

Yamashita, Hideomi; Nakagawa, Keiichi; Tago, Masao; Igaki, Hiroshi; Shiraishi, Kenshirou; Nakamura, Naoki; Sasano, Nakashi; Yamakawa, Sen; Ohtomo, Kuni

2006-04-01

We describe the clinical presentation, evaluation, management and outcome of patients experiencing small bowel perforation following radiation therapy for cervical cancer. A database consisting of 95 Japanese women with stage 0-4 A cervix cancer treated between 1991 and 2004 contained seven patients (7.4%) with small bowel perforation. The median age at the time of perforation was 72.5 years (range 62-78). The median time from completion of radiotherapy to perforation was 6 months (range 2-58). Surgery (one small bowel resection and anastomosis with diversion; six small bowel resection and anastomosis) was performed immediately in all seven patients. One of seven patients died of small bowel perforation (i.e. mortality rate was 14%). Bowel adhesion was detected during the operation in only three cases (43%). Signs of peritonitis were absent in six cases (86%). Severe abdominal pain was seen in all seven patients. The perforation site was ileum in all seven cases. In all patients, pathological changes were compatible with postirradiation injury of the gastrointestinal tract. The presenting complaints of patients with bowel perforation following radiotherapy vary, and signs of peritonitis may be absent. Emergency physicians must be alert for these complications in patients who have been treated with radiotherapy.

[Clinical application of self-made drainage tube with balloon for iatrogenic colonic perforation].

PubMed

Liu, Bing-rong; Li, Hui; Zhao, Li-xia; Song, Ji-tao; Wang, Yan-jun; Chen, Jing; Liu, Wei

2012-07-01

To investigate the clinical efficacy of colonic bypass drainage by self-made drainage tube with balloon for iatrogenic colonic perforation. A retrospective analysis of 8 patients with iatrogenic colonic perforations from January 2009 to March 2011 was performed. Self-made drainage tubes with balloon were placed in the bowel lumen endoscopically after perforations were closed with endoclips or endoloops under endoscope. The inflatable balloon at the front-end of the tube was fixed at the mouth side of colonic perforation to achieve continuous drainage of stool and intestinal juice. Endoscopic bypass continuous drainage by using self-made drainage tube with balloon was successfully carried out in all the 8 patients. All the perforations healed and no surgical intervention required. Bypass drainage continued for 3-10 days(mean 7.6 days). One patient received colonoscopy 3 days after the procedure, and displacement of the drainage tube was noticed requiring endoscopic adjustment. All the drainage tubes were removed uneventfully, and no ulceration or perforation occurred at balloon fixed site after removal. After follow up ranging from 12 to 36 months, no chronic fistula, adhesive obstruction, or abdominal infection occurred. Colonic bypass drainage by self-made drainage tube with balloon for iatrogenic colonic perforation is simple, feasible, safe and reliable.

Safe procedure in endoscopic submucosal dissection for colorectal tumors focused on preventing complications

PubMed Central

Yoshida, Naohisa; Yagi, Nobuaki; Naito, Yuji; Yoshikawa, Toshikazu

2010-01-01

Endoscopic submucosal dissection (ESD) is efficient for en bloc resection of large colorectal tumors. However, it has several technical difficulties, because the wall of the colon is thin and due to the winding nature of the colon. The main complications of ESD comprise postoperative perforation and hemorrhage, similar to endoscopic mucosal resection (EMR). In particular, the rate of perforation in ESD is higher than that in EMR. Perforation of the colon can cause fatal peritonitis. Endoscopic clipping is reported to be an efficient therapy for perforation. Most cases with perforation are treated conservatively without urgent surgical intervention. However, the rate of postoperative hemorrhage in ESD is similar to that in EMR. Endoscopic therapy including endoscopic clipping is performed and most of the cases are treated conservatively without blood transfusion. In blood examination, some degree of inflammation is detected after ESD. For the standardization of ESD, it is most important to decrease the rate of perforation. Adopting a safe strategy for ESD and a suitable choice of knife are both important ways of preventing perforation. Moreover, appropriate training and increasing experience can improve the endoscopic technique and can decrease the rate of perforation. In this review, we describe safe procedures in ESD to prevent complications, the complications of ESD and their management. PMID:20379999

Penetration and perforation of skin by bullets and missiles. A review of the literature.

PubMed

DiMaio, V J

1981-06-01

A review of the literature on perforation of skin by bullets and missiles indicates that there is a range of velocity below which a missile cannot perforate the skin. Velocities of between 38.1 and 61.6 meters/second (125 and 202 ft./second) will produce at least minimal damage to the surface of the skin, though without perforation. In order for a missile to perforate the skin and enter the underlying subcutaneous tissue and muscle, a minimum velocity in the order of 70 meters/second (230 ft./second) is necessary with an energy/area of presentation of approximately 2.1 m-kg/cm2.

Delayed lead perforation: a disturbing trend.

PubMed

Khan, Mohammed N; Joseph, George; Khaykin, Yaariv; Ziada, Khaled M; Wilkoff, Bruce L

2005-03-01

Delayed lead perforation (occurring more than 1 month after implantation) is a rare complication. Its pathophysiology and optimal management are currently unclear. Three cases of delayed lead perforation (6-10 month) were identified in patients with low-profile active fixation leads. All cases presented in a subacute fashion with pleuritic chest pain with confirmatory chest x-ray and device interrogation. Given the potential complications of a perforated lead, all cases had the lead extracted under TEE observation with cardiac surgery backup in the operating room. All patients tolerated extraction without complication. Based on these cases, we recommend a management scheme for patients who present with delayed lead perforation.

[Experitoneal bladder perforation due to in-dwelling urethral catheter successfully treated by urethral drainage: a case report].

PubMed

Okuda, Hidenobu; Tei, Norihide; Shimizu, Kiyonori; Imazu, Tetsuo; Yoshimura, Kazuhiro; Kiyohara, Hisakazu

2008-07-01

Perforation of the bladder related to long-term indwelling urethral catheter is a rare and serious complication. A 85-year-old man with an indwelling urethral catheter presented severe hematuria, abdominal pain with rebound tenderness and muscular tension over the suprapubic area after the exchange of the urethral catheter. Computed tomography and cystogram revealed experitoneal bladder perforation due to indwelling catheter. Three weeks after the indwelling urethral catheter had been placed, the perforation was closed. In most cases, laparotomy and suprapubic cystostomy are performed. We describe the case of experitoneal bladder perforation successfully treated by urethral drainage.

Quasi-steady acoustic response of wall perforations subject to a grazing-bias flow combination

NASA Astrophysics Data System (ADS)

Tonon, D.; Moers, E. M. T.; Hirschberg, A.

2013-04-01

Well known examples of acoustical dampers are the aero-engine liners, the IC-engine exhaust mufflers, and the liners in combustion chambers. These devices comprise wall perforations, responsible for their sound absorbing features. Understanding the effect of the flow on the acoustic properties of a perforation is essential for the design of acoustic dampers. In the present work the effect of a grazing-bias flow combination on the impedance of slit shaped wall perforations is experimentally investigated by means of a multi-microphone impedance tube. Measurements are carried out for perforation geometries relevant for in technical applications. The focus of the experiments is on the low Strouhal number (quasi-steady) behavior. Analytical models of the steady flow and of the low frequency aeroacoustic behavior of a two-dimensional wall perforation are proposed for the case of a bias flow directed from the grazing flow towards the opposite side of the perforated wall. These theoretical results compare favorably with the experiments, when a semi-empirical correction is used to obtain the correct limit for pure bias flow.

Microstructure based model for sound absorption predictions of perforated closed-cell metallic foams.

PubMed

Chevillotte, Fabien; Perrot, Camille; Panneton, Raymond

2010-10-01

Closed-cell metallic foams are known for their rigidity, lightness, thermal conductivity as well as their low production cost compared to open-cell metallic foams. However, they are also poor sound absorbers. Similarly to a rigid solid, a method to enhance their sound absorption is to perforate them. This method has shown good preliminary results but has not yet been analyzed from a microstructure point of view. The objective of this work is to better understand how perforations interact with closed-cell foam microstructure and how it modifies the sound absorption of the foam. A simple two-dimensional microstructural model of the perforated closed-cell metallic foam is presented and numerically solved. A rough three-dimensional conversion of the two-dimensional results is proposed. The results obtained with the calculation method show that the perforated closed-cell foam behaves similarly to a perforated solid; however, its sound absorption is modulated by the foam microstructure, and most particularly by the diameters of both perforation and pore. A comparison with measurements demonstrates that the proposed calculation method yields realistic trends. Some design guides are also proposed.

The effect of perforations on the ballistics of a flare-stabilized projectile

NASA Astrophysics Data System (ADS)

Mermagen, W. H.; Yalamanchili, R. J.

Flight tests of two 35/105 mm flare stabilized projectile configurations were conducted. The projectiles were fired from the M68 tank cannon at Mach 4.0 using a standard M735 sabot. Flight data were obtained with a doppler velocimeter. The perforated flare projectiles showed a reduced drag for M greater than 1.7, which increased significantly at velocities below M 1.7, while the solid flare rounds had a slightly higher drag above Mach 1.7. Below Mach 1.7, the solid flare rounds had less drag than the perforated flare round. Both solid and perforated flare projectiles had a maximum range of less than 8.0 kilometers. The effects of the perforations on the flight performance were small. The flight data are compared to previous tests of the German-made 'LKL' projectile. The differences in flight performance between solid flares, flares with perforations, and the LKL-perforated flare rounds were small and of no practical consequence. Dispersion tests of the solid-flare stabilized projectiles were conducted at one, two, and three kilometers with excellent results. Very low dispersions were observed at all ranges.

Definitive or conservative surgery for perforated gastric ulcer?--An unresolved problem.

PubMed

Sarath Chandra, Sistla; Kumar, S Siva

2009-04-01

Gastric ulcer perforation has not been the focus of many studies. In addition there is a need to analyze the results of gastric perforation separately and not along with duodenal perforations, to identify the factors influencing the outcome and to develop strategies for its management. Retrospective analysis of 54 patients presenting with gastric perforation. Mean age of the patients was 44.5 years with male preponderance. Morbidity following Closure of the perforation, acid reduction surgery and resection was not significantly different. Overall mortality was 16.6% with highest mortality 24.1% following simple closure. Mortality following simple closure and definitive surgery was not significantly different. Univariate analysis revealed preoperative shock, associated medical illness and surgical delay to be significant factors for mortality whereas on multivariate analysis, preoperative shock was the only independent predictor of mortality. Mortality increased with increasing Boey score but the association between the type of surgery and probability of survival was not statistically significant. Boey risk score is useful in predicting the outcome of surgical treatment for gastric perforation. Definitive surgery is not associated with greater morbidity or mortality compared to simple closure.

Cyclopentadithiophene-Benzothiadiazole Donor-Acceptor Polymers as Prototypical Semiconductors for High-Performance Field-Effect Transistors.

PubMed

Li, Mengmeng; An, Cunbin; Pisula, Wojciech; Müllen, Klaus

2018-05-15

Donor-acceptor (D-A) conjugated polymers are of great interest as organic semiconductors, because they offer a rational tailoring of the electronic properties by modification of the donor and acceptor units. Nowadays, D-A polymers exhibit field-effect mobilities on the order of 10 -2 -10 0 cm 2 V -1 s -1 , while several examples showed a mobility over 10 cm 2 V -1 s -1 . The development of cyclopentadithiophene-benzothiadiazole (CDT-BTZ) copolymers one decade ago represents an important step toward high-performance organic semiconductors for field-effect transistors. The significant rise in field-effect mobility of CDT-BTZ in comparison to the existing D-A polymers at that time opened the door to a new research field with a large number of novel D-A systems. From this point, the device performance of CDT-BTZ was gradually improved by a systematic optimization of the synthesis and polymer structure as well as by an efficient solution processing into long-range ordered thin films. The key aspect was a comprehensive understanding of the relation between polymer structure and solid-state organization. Due to their fundamental role for the field of D-A polymers in general, this Account will for the first time explicitly focus on prototypical CDT-BTZ polymers, while other reviews provide an excellent general overview on D-A polymers. The first part of this Account discusses strategies for improving the charge carrier transport, focusing on chemical aspects. Improved synthesis as an essential stage toward high purity, and high molecular weight is a prerequisite for molecular order. The modification of substituents is a further crucial feature to tune the CDT-BTZ packing and self-assembly. Linear alkyl side chains facilitate intermolecular π-stacking interactions, while branched ones increase solubility and alter the polymer packing. Additional control over the supramolecular organization of CDT-BTZ polymers is introduced by alkenyl substituents via their cis-trans isomerization. The last discussed chemical concept is based on heteroatom variation within the CDT unit. The relationships found experimentally for CDT-BTZ between polymer chemical structure, solid-state organization, and charge carrier transport are explained by means of theoretical simulations. Besides the effects of molecular design, the second part of this Account discusses the processing conditions from solution. The film microstructure, defined as a mesoscopic domain organization, is critically affected by solution processing. Suitable processing techniques allow the formation of a long-range order and a uniaxial orientation of the CDT-BTZ chains, thus lowering the trapping density of grain boundaries for charge carriers. For instance, alignment of the CDT-BTZ polymer by dip-coating yields films with a pronounced structural and electrical anisotropy and favors a fast migration of charge carriers along the conjugated backbones in the deposition direction. By using film compression with the assistance of an ionic liquid, one even obtains CDT-BTZ films with a band-like transport and a transistor hole mobility of 10 cm 2 V -1 s -1 . This device performance is attributed to large domains in the compressed films being formed by CDT-BTZ with longer alkyl chains, which establish a fine balance between polymer interactions and growth kinetics during solvent evaporation. On the basis of the prototypical semiconductor CDT-BTZ, this Account provides general guidelines for achieving high-performance polymer transistors by taking into account the subtle balance of synthetic protocol, molecular design, and processing.

Perforated Appendicitis After Colonoscopy

PubMed Central

Johnston, Paul

2008-01-01

Background: Acute appendicitis is a rare complication of colonoscopy that has been reported only 12 times in the English-language literature and is usually associated with obstruction of the appendiceal lumen with fecal matter during colonoscopy. None of the previous reports have described findings of perforation of the appendix within 24 hours of colonoscopy. Methods: We present the case report of a patient who underwent urgent laparotomy within 16 hours of colonos-copy for findings of free intraabdominal air and peritonitis from acute perforated appendicitis. Results: Laparoscopy confirmed 2 perforations of the appendix and diffuse peritonitis. Laparotomy was necessary to perform appendectomy, exclude a right colonic injury, and control intraabdominal sepsis. Conclusion: In patients with abdominal pain who have had a recent colonoscopy, a high index of suspicion is necessary for accurate diagnosis of perforated appendicitis. Perforation can occur hours after colonoscopy even when a biopsy is not performed. PMID:18765066

Active Control of Liner Impedance by Varying Perforate Orifice Geometry

NASA Technical Reports Server (NTRS)

Ahuji, K. K.; Gaeta, R. J., Jr.

2000-01-01

The present work explored the feasibility of controlling the acoustic impedance of a resonant type acoustic liner. This was accomplished by translating one perforate over another of the same porosity creating a totally new perforate that had an intermediate porosity. This type of adjustable perforate created a variable orifice perforate whose orifices were non-circular. The key objective of the present study was to quantify, the degree of attenuation control that can be achieved by applying such a concept to the buried septum in a two-degree-of-freedom (2DOF) acoustic liner. An additional objective was to examine the adequacy of the existing impedance models to explain the behavior of the unique orifice shapes that result from the proposed silding perforate concept. Different orifice shapes with equivalent area were also examined to determine if highly non-circular orifices had a significant impact on the impedance.

[An Analysis of Perforated Gastric Cancer with Acute Peritonitis in Our Hospital].

PubMed

Adachi, Shinichi; Endo, Shunji; Chinen, Yoshinao; Itakura, Hiroaki; Takayama, Hirotoshi; Tsuda, Yujiro; Ueda, Masami; Nakashima, Shinsuke; Ohta, Katsuya; Ikenaga, Masakazu; Yamada, Terumasa

2018-01-01

Perforated gastric cancer is relatively rare and the incidence is reported about 1% of all the cases of gastric cancer. We retrospectively analyzed the clinical data of the consecutive 12 patients with perforated gastric cancer who underwent operation in our hospital between January 2005 and December 2016. There were 5 men and 7 women, with an average age of 65.8 years old(34-87). Perforated gastric cancer occurred in the region U(1 cases), M(6 cases), L(5 cases). There were 11 cases with distant metastasis. We could successfully diagnosed as perforated gastric cancer in 8 cases before emergency operation. Gastrectomy was performed in 5 cases. However, the curative resection was performed only 1 case. Prognosis of perforated gastric cancer is poor. We considered as an appropriate two-step surgical strategy that the first step of surgery is an acute peritonitis treatment followed by radical gastrectomy with lymphadenectomy.

Successful Deep Inferior Epigastric Perforator Flap Harvest despite Preoperative Therapeutic Subcutaneous Heparin Administration into the Abdominal Pannus.

PubMed

Duncumb, Joseph W; Miyagi, Kana; Forouhi, Parto; Malata, Charles M

2016-01-01

Abdominal free flaps for microsurgical breast reconstruction are most commonly harvested based on the deep inferior epigastric vessels that supply skin and fat via perforators through the rectus muscle and sheath. Intact perforator anatomy and connections are vital for subsequent optimal flap perfusion and avoidance of necrosis, be it partial or total. The intraflap vessels are delicate and easily damaged and it is generally advised that patients should avoid heparin injection into the abdominal pannus preoperatively as this may compromise the vascular perforators through direct needle laceration, pressure from bruising, haematoma formation, or perforator thrombosis secondary to external compression. We report three cases of successful deep inferior epigastric perforator (DIEP) flap harvest despite patients injecting therapeutic doses of low molecular weight heparin into their abdomens for thrombosed central venous lines (portacaths™) used for administering primary chemotherapy in breast cancer.

Successful Deep Inferior Epigastric Perforator Flap Harvest despite Preoperative Therapeutic Subcutaneous Heparin Administration into the Abdominal Pannus

PubMed Central

Miyagi, Kana; Forouhi, Parto

2016-01-01

Abdominal free flaps for microsurgical breast reconstruction are most commonly harvested based on the deep inferior epigastric vessels that supply skin and fat via perforators through the rectus muscle and sheath. Intact perforator anatomy and connections are vital for subsequent optimal flap perfusion and avoidance of necrosis, be it partial or total. The intraflap vessels are delicate and easily damaged and it is generally advised that patients should avoid heparin injection into the abdominal pannus preoperatively as this may compromise the vascular perforators through direct needle laceration, pressure from bruising, haematoma formation, or perforator thrombosis secondary to external compression. We report three cases of successful deep inferior epigastric perforator (DIEP) flap harvest despite patients injecting therapeutic doses of low molecular weight heparin into their abdomens for thrombosed central venous lines (portacaths™) used for administering primary chemotherapy in breast cancer. PMID:27651974

Perforated peptic ulcer (PPU) in pregnancy during Ramadan fasting.

PubMed

Gali, B M; Ibrahim, A G; Chama, C M; Mshelia, H B; Abubakar, A; Takai, I U; Takie, U; Bwala, S

2011-01-01

Perforated Peptic Ulcer (PPU) is extremely rare in pregnancy. We report a case of perforated peptic ulcer in pregnancy during Ramadan fasting. The patient is a 16 years old primigravida who presented with features of peritonitis at 28weeks of gestation while fasting during Ramadan. Ultrasound scan reported a singleton live fetus at 28 weeks gestation. At laparotomy via upper midline incision; a 1 cm roundish perforation located on the duodenum anteriorly was found with about a litre of gastric juice mixed with blood and food particles in the peritoneal cavity. The perforation was close transversely with omental patch (Modified Graham's patch) and peritoneal lavage done with warm saline. She had a preterm delivery of a 1 kg baby 3 days post-operatively by a spontaneous vaginal delivery, but the baby died 3 days later. Perforated Peptic Ulcer(PPU) though rare in pregnancy can occur and fasting can be a risk factor.

Giant perforated marginal ulcer after laparoscopic Roux-en-Y gastric bypass.

PubMed

Wang, Edward; Blackham, Ruth; Tan, Jeremy; Hamdorf, Jeffrey

2017-04-11

Perforation of a marginal ulcer (MU) is a complication of Roux -en-Y gastric bypass that can be life-threatening. We report a case of a perforated MU that presented 7 months after surgery with several interesting points for discussion. Firstly, the presentation of the ulcer was cryptic with unreliable investigations. Secondly, the ulcer presented again even after anastomotic revision surgery. Finally, the ulcer and the sepsis associated with perforation presented after months of poor nutritional intake with profound hypoalbuminaemia. Perforated MUs causing malnutrition pose clinicians with the difficult decision of which operation to offer; patch repair, revision of the anastomosis or reversal surgery. This case illustrates that primary reversal surgery for a perforated recurrent MU may be the most appropriate surgical management in this clinical situation. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Risk factors affecting human traumatic tympanic membrane perforation regeneration therapy using fibroblast growth factor-2.

PubMed

Lou, Zhengcai; Yang, Jian; Tang, Yongmei; Xiao, Jian

2015-01-01

The use of growth factors to achieve closure of human traumatic tympanic membrane perforations (TMPs) has recently been demonstrated. However, pretreatment factors affecting healing outcomes have seldom been discussed. The objective of this study was to evaluate pretreatment factors contributing to the success or failure of healing of TMPs using fibroblast growth factor-2 (FGF-2). A retrospective cohort study of 99 patients (43 males, 56 females) with traumatic TMPs who were observed for at least 6 months after FGF-2 treatment between March 2011 and December 2012. Eleven factors considered likely to affect the outcome of perforation closure were evaluated statistically using univariate and multivariate logistic regression analysis. Each traumatic TMP was treated by direct application of FGF-2. Complete closure versus failure to close. In total, 99 patients were analyzed. The total closure rate was 92/99 (92.9%) at 6 months; the mean closure time was 10.59 ±  6.81 days. The closure rate did not significantly differ between perforations with or without inverted edges (100.0% vs. 91.4%, p = 0.087), among different size groups (p = 0.768), or among different periods of exposure to injury (p = 0.051). However, the closure rate was significantly different between the high- and low-dose FGF-2 groups (85.0% vs. 98.3%, p = 0.010) and between perforations where the umbo or malleus was or was not involved in perforation (85.4% vs. 98.3%, p = 0.012). Additionally, univariate logistic regression analysis tests showed that it was difficult to achieve healing of these perforations with a history of chronic otitis media or residual TM calcification (p = 0.006), the umbo or malleus was involved in perforation (p = 0.038), and with a high dose of FGF-2 (p = 0.035) compared with control groups. Multivariate logistic regression analysis showed that only a history of chronic otitis media and residual TM calcification and perforation close to the umbo or malleus were associated with non-healing of the TM perforation (p = 0.03 and p = 0.017, respectively) with relative risk factors. Direct application of FGF-2 can be used in all traumatic TMPs, the size of the perforation and inverted edges did not affect the closure rate, and the most beneficial dose was sufficient to keep the residual eardrum environment moist, but without adding liquid. Additionally, multivariate logistic regression analysis revealed that a large perforation was not a major risk factor for nonhealing of TM perforations. However, a history of chronic otitis media, residual TM calcification and involvement of the umbo or malleus in perforation were significant risk factors.

An Experimentally Validated Numerical Modeling Technique for Perforated Plate Heat Exchangers

PubMed Central

Nellis, G. F.; Kelin, S. A.; Zhu, W.; Gianchandani, Y.

2010-01-01

Cryogenic and high-temperature systems often require compact heat exchangers with a high resistance to axial conduction in order to control the heat transfer induced by axial temperature differences. One attractive design for such applications is a perforated plate heat exchanger that utilizes high conductivity perforated plates to provide the stream-to-stream heat transfer and low conductivity spacers to prevent axial conduction between the perforated plates. This paper presents a numerical model of a perforated plate heat exchanger that accounts for axial conduction, external parasitic heat loads, variable fluid and material properties, and conduction to and from the ends of the heat exchanger. The numerical model is validated by experimentally testing several perforated plate heat exchangers that are fabricated using microelectromechanical systems based manufacturing methods. This type of heat exchanger was investigated for potential use in a cryosurgical probe. One of these heat exchangers included perforated plates with integrated platinum resistance thermometers. These plates provided in situ measurements of the internal temperature distribution in addition to the temperature, pressure, and flow rate measured at the inlet and exit ports of the device. The platinum wires were deposited between the fluid passages on the perforated plate and are used to measure the temperature at the interface between the wall material and the flowing fluid. The experimental testing demonstrates the ability of the numerical model to accurately predict both the overall performance and the internal temperature distribution of perforated plate heat exchangers over a range of geometry and operating conditions. The parameters that were varied include the axial length, temperature range, mass flow rate, and working fluid. PMID:20976021

A shovel with a perforated blade reduces energy expenditure required for digging wet clay.

PubMed

Harivanam, Sridhar; Marklin, Richard W; Papanek, Paula E; Cariapa, Vikram

2010-08-01

A shovel with a blade perforated with small holes was tested to see whether a worker would use less whole-body energy to dig wet clay than with a shovel with an opaque blade. A perforated shovel is hypothesized to require less whole-body energy on the basis of adhesion theory; a smaller surface area would require less physical effort to dig and release soil from the blade. The study involved 13 workers from an electric utility who dug wet clay with two 1.5-m long-handled point shovels, which differed only in blade design (perforated and opaque). Oxygen consumption was measured with a portable system while each worker dug wet clay at a self-regulated pace for 10 min. There was no significant difference in number of scoops dug during the 10-min sessions, but workers dug 9.5% more weight of clay with the perforated shovel than with the conventional shovel (404 kg vs. 369 kg, respectively). Furthermore, stable oxygen uptake normalized to weight of participant and to the weight of clay dug revealed that participants expended 11.7% less relative energy per kilogram of clay dug with the perforated shovel. A point shovel with a perforated blade is recommended for digging and shoveling wet clay. However, the extra weight that workers chose to dig with the perforated shovel may increase the loading on the spine and may offset the metabolic advantages. Manual shoveling is a common task, and workers may experience less whole-body and muscle fatigue when using a perforated shovel.

An Experimentally Validated Numerical Modeling Technique for Perforated Plate Heat Exchangers.

PubMed

White, M J; Nellis, G F; Kelin, S A; Zhu, W; Gianchandani, Y

2010-11-01

Cryogenic and high-temperature systems often require compact heat exchangers with a high resistance to axial conduction in order to control the heat transfer induced by axial temperature differences. One attractive design for such applications is a perforated plate heat exchanger that utilizes high conductivity perforated plates to provide the stream-to-stream heat transfer and low conductivity spacers to prevent axial conduction between the perforated plates. This paper presents a numerical model of a perforated plate heat exchanger that accounts for axial conduction, external parasitic heat loads, variable fluid and material properties, and conduction to and from the ends of the heat exchanger. The numerical model is validated by experimentally testing several perforated plate heat exchangers that are fabricated using microelectromechanical systems based manufacturing methods. This type of heat exchanger was investigated for potential use in a cryosurgical probe. One of these heat exchangers included perforated plates with integrated platinum resistance thermometers. These plates provided in situ measurements of the internal temperature distribution in addition to the temperature, pressure, and flow rate measured at the inlet and exit ports of the device. The platinum wires were deposited between the fluid passages on the perforated plate and are used to measure the temperature at the interface between the wall material and the flowing fluid. The experimental testing demonstrates the ability of the numerical model to accurately predict both the overall performance and the internal temperature distribution of perforated plate heat exchangers over a range of geometry and operating conditions. The parameters that were varied include the axial length, temperature range, mass flow rate, and working fluid.

Analysis of series resonant converter with series-parallel connection

NASA Astrophysics Data System (ADS)

Lin, Bor-Ren; Huang, Chien-Lan

2011-02-01

In this study, a parallel inductor-inductor-capacitor (LLC) resonant converter series-connected on the primary side and parallel-connected on the secondary side is presented for server power supply systems. Based on series resonant behaviour, the power metal-oxide-semiconductor field-effect transistors are turned on at zero voltage switching and the rectifier diodes are turned off at zero current switching. Thus, the switching losses on the power semiconductors are reduced. In the proposed converter, the primary windings of the two LLC converters are connected in series. Thus, the two converters have the same primary currents to ensure that they can supply the balance load current. On the output side, two LLC converters are connected in parallel to share the load current and to reduce the current stress on the secondary windings and the rectifier diodes. In this article, the principle of operation, steady-state analysis and design considerations of the proposed converter are provided and discussed. Experiments with a laboratory prototype with a 24 V/21 A output for server power supply were performed to verify the effectiveness of the proposed converter.

Brief Report: Risk of Gastrointestinal Perforation Among Rheumatoid Arthritis Patients Receiving Tofacitinib, Tocilizumab, or Other Biologic Treatments.

PubMed

Xie, Fenglong; Yun, Huifeng; Bernatsky, Sasha; Curtis, Jeffrey R

2016-11-01

To evaluate gastrointestinal (GI) perforation in rheumatoid arthritis (RA) patients receiving tofacitinib, tocilizumab, or other biologic agents. Using health plan data from 2006 through 2014, RA patients without prior GI perforation were identified. Those in whom treatment with tofacitinib or a biologic agent was being initiated were followed up for incident GI perforation with hospitalization. Crude incidence rates were calculated by exposure. Adjusted Cox proportional hazards models were used to evaluate the association between GI perforation and exposures. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated. A cohort of 167,113 RA patients was analyzed. Among them, 4,755 began treatment with tofacitinib, 11,705 with tocilizumab, 115,047 with a tumor necrosis factor inhibitor (TNFi), 31,214 with abatacept, and 4,392 with rituximab. Compared to TNFi recipients, abatacept recipients were older, tofacitinib and rituximab recipients were younger, and tocilizumab recipients were similar in age. Patients beginning treatment with a non-TNFi agent were more likely to have previously received biologic agents than patients beginning treatment with a TNFi. The incidence of GI perforation per 1,000 patient-years was 0.86 (tofacitinib), 1.55 (tocilizumab), 1.07 (abatacept), 0.73 (rituximab), and 0.83 (TNFi). Most perforations occurred in the lower GI tract: the incidence of lower GI tract perforation per 1,000 patient-years was 0.86 (tofacitinib), 1.26 (tocilizumab), 0.76 (abatacept), 0.48 (rituximab), and 0.46 (TNFi). Lower GI tract perforation risk was significantly elevated with tocilizumab treatment, and numerically elevated with tofacitinib treatment, versus treatment with TNFi. Adjusted HRs were 2.51 (95% CI 1.31-4.80) for tocilizumab and 1.94 (95% CI 0.49-7.65) for tofacitinib. Older age (HR 1.16 per 5 years [95% CI 1.10-1.22]), diverticulitis/other GI conditions (HR 3.25 [95% CI 1.62-6.50]), and prednisone use at >7.5 mg/day (HR 2.29 [95% CI 1.39-3.78]) were associated with lower GI tract perforation. The incidence of upper GI tract perforation was similar among all drug exposures. The risk of lower GI tract perforation associated with tocilizumab treatment, and possibly tofacitinib treatment, is elevated compared to that associated with TNF blockade. © 2016, American College of Rheumatology.

Peritonitis Following Duodenal Ulcer Perforation in a Newborn: A Case Report.

PubMed

Amouei, Abdolhamid; Ehsani, Fatemeh; Zarch, Mojtaba Babaei; Tabatabaei, Seyed Mostafa; Ghodratipour, Zahra

2016-11-01

Duodenal ulcer is an uncommon condition in children, that is why it is not usually considered as the differential diagnosis unless it presents with complications including perforation and haemorrhage. Moreover, duodenal ulcer perforation is an uncommon entity in paediatric age group. Early diagnosis and treatment is crucial in order to improve survival. A three-day-old male neonate was admitted to our hospital because of abdominal distension. The neonate was lethargic. He underwent laparotomy. There was a perforated ulcer, 5×5mm in size, on the anterior aspect of the first part of the duodenum. The perforated ulcer was closed with a single layer. Six-month follow-up revealed no abnormality.

Intestinal volvulus and perforation caused by multiple magnet ingestion: report of a case.

PubMed

Ilçe, Zekeriya; Samsum, Hakan; Mammadov, Emil; Celayir, Sinan

2007-01-01

Ingested magnets can cause intestinal fistulas, perforation, and obstruction. There have been reports of magnet ingestion causing intestinal volvulus, but multiple magnet ingestion causing perforation and intestinal volvulus in a child is very unusual. We report the case of a 4-year-old girl, who ingested four magnets she acquired as toys, which caused intestinal volvulus and perforation as a result of pressure necrosis, several days after ingestion. At surgery we repaired two perforations, but additional bowel resection was not required. The patient was discharged on postoperative day 10. If multiple magnet ingestion is suspected in a child, the child must be monitored carefully. If there are signs of obstruction, emergency surgery is mandatory.

Material development for laminar flow control wing panels

NASA Technical Reports Server (NTRS)

Meade, L. E.

1977-01-01

The absence of suitable porous materials or techniques for the economic perforation of surface materials has previously restricted the design of laminar flow control (LFC) wing panels to a consideration of mechanically slotted LFC surfaces. A description is presented of a program which has been conducted to exploit recent advances in materials and manufacturing technology for the fabrication of reliable porous or perforated LFC surface panels compatible with the requirements of subsonic transport aircraft. Attention is given to LFC design criteria, surface materials, surface concepts, the use of microporous composites, perforated composites, and perforated metal. The described program was successful in that fabrication processes were developed for producing predictable perforated panels both of composite and of metal.

Colonic perforation in the first few hours of life associated with rhizomelic chondrodysplasia punctata.

PubMed

Fairbanks, Timothy; Emil, Sherif

2005-08-01

Rhizomelic chondrodysplasia punctata (RCP), a rare autosomal recessive disease characterized by a disorder of peroxisome metabolism, has been shown to affect multiple organ systems. A neonate presenting with a colonic perforation in the first few hours of life was subsequently diagnosed with RCP. A literature search revealed no previous reports of intestinal perforation associated with RCP. Intestinal perforation should be added to the list of medical complications associated with RCP.

Risk of surgical glove perforation in oral and maxillofacial surgery.

PubMed

Kuroyanagi, N; Nagao, T; Sakuma, H; Miyachi, H; Ochiai, S; Kimura, Y; Fukano, H; Shimozato, K

2012-08-01

Oral and maxillofacial surgery, which involves several sharp instruments and fixation materials, is consistently at a high risk for cross-contamination due to perforated gloves, but it is unclear how often such perforations occur. This study aimed to address this issue. The frequency of the perforation of surgical gloves (n=1436) in 150 oral and maxillofacial surgeries including orthognathic surgery (n=45) was assessed by the hydroinsufflation technique. Orthognathic surgery had the highest perforation rate in at least 1 glove in 1 operation (91.1%), followed by cleft lip and palate surgery (55.0%), excision of oral soft tumour (54.5%) and dental implantation (50.0%). The perforation rate in scrub nurses was 63.4%, followed by 44.4% in surgeons and first assistants, and 16.3% in second assistants. The odds ratio for the perforation rate in orthognathic surgery versus other surgeries was 16.0 (95% confidence interval: 5.3-48.0). The protection rate offered by double gloving in orthognathic surgery was 95.2%. These results suggest that, regardless of the surgical duration and blood loss in all fields of surgery, orthognathic surgery must be categorized in the highest risk group for glove perforation, following gynaecological and open lung surgery, due to the involvement of sharp objects. Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Peroneal perforator pedicle propeller flap for lower leg soft tissue defect reconstruction: Clinical applications and treatment of venous congestion

PubMed Central

Liu, Yiyang; Zhang, Chun; Guo, Qiaofeng; Huang, Wenhua; Wong, Kelvin Kian Loong; Chang, Shimin

2017-01-01

Objective To describe the characteristics of the perforator vessel in the peroneal artery of the lower leg and to explore the use of perforator pedicle propeller flaps to repair soft tissue defects in the lower leg, heel and foot. Methods This retrospective study enrolled patients with soft tissue defects of the distal lower leg, heel and foot who underwent surgery using peroneal perforator-based propeller flaps. The peroneal artery perforators were identified preoperatively by colour duplex Doppler ultrasound. The flap was designed based on the preoperatively-identified perforator location, with the posterior border of the fibula employed as an axis, and the perforator vessel as the pivot point of rotation. Patients were followed-up to determine the outcomes. Results The study analysed 36 patients (mean age, 39.7 years). The majority of the soft tissue defects were on the heel (20; 55.6%). The donor-site of the flap was closed in 11 patients by direct suturing and skin grafting was undertaken in 25 patients. Postoperative complications included venous congestion (nine patients), which was managed with delayed wound coverage and bleeding therapy. All wounds were eventually cured and the flaps were cosmetically acceptable. Conclusions The peroneal perforator pedicle propeller flap is an appropriate choice to repair soft tissue defects of the distal limbs. PMID:28345420

Peroneal perforator pedicle propeller flap for lower leg soft tissue defect reconstruction: Clinical applications and treatment of venous congestion.

PubMed

Shen, Lifeng; Liu, Yiyang; Zhang, Chun; Guo, Qiaofeng; Huang, Wenhua; Wong, Kelvin Kian Loong; Chang, Shimin

2017-06-01

Objective To describe the characteristics of the perforator vessel in the peroneal artery of the lower leg and to explore the use of perforator pedicle propeller flaps to repair soft tissue defects in the lower leg, heel and foot. Methods This retrospective study enrolled patients with soft tissue defects of the distal lower leg, heel and foot who underwent surgery using peroneal perforator-based propeller flaps. The peroneal artery perforators were identified preoperatively by colour duplex Doppler ultrasound. The flap was designed based on the preoperatively-identified perforator location, with the posterior border of the fibula employed as an axis, and the perforator vessel as the pivot point of rotation. Patients were followed-up to determine the outcomes. Results The study analysed 36 patients (mean age, 39.7 years). The majority of the soft tissue defects were on the heel (20; 55.6%). The donor-site of the flap was closed in 11 patients by direct suturing and skin grafting was undertaken in 25 patients. Postoperative complications included venous congestion (nine patients), which was managed with delayed wound coverage and bleeding therapy. All wounds were eventually cured and the flaps were cosmetically acceptable. Conclusions The peroneal perforator pedicle propeller flap is an appropriate choice to repair soft tissue defects of the distal limbs.

Laparoscopic endoloop technique - A novel approach of managing iatrogenic caecal perforation and literature review.

PubMed

Merali, N; Hussain, A

2015-01-01

An iatrogenic caecal perforation is rare, but a serious complication associated with significant morbidity and mortality. We present a 4min and 50s video on a new improvisation undertaken during laparoscopic management of post-polypectomy caecal perforation. Our patient presented with an acute abdomen following endoscopic polypectomy. At surgery, the site of caecal perforation was close to the appendicular base with devitalization tissue, secondary to diathermy usage. The hallmark of safety within this novel technique included fresh healthy tissue margins within the endoloop (detachable snare ligation) and ensuring no ischemic tissue was gathered. Complete freeing of the appendix and meso-appendicular base was required and securing three endoloops proximal to the site of perforation. The post-operative course was uneventful. The World Society of Emergency Surgery (WSES) 2013 guidelines suggested an early laparoscopic approach is a safe and effective treatment for colonoscopy-related colonic perforation. There are no national guidelines and the management is dictated by the clinical condition of the patient, co-morbidity, size and site of perforation as well as the scale of bowel preparation, and surgical experience. The endoloop technique described, undertaken during a laparoscopy is a novel approach. It is a simple and effective method, reminding clinicians to adapt techniques when necessary. Nevertheless, it is only limited to perforations around the appendicular base. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Laparoscopic endoloop technique – A novel approach of managing iatrogenic caecal perforation and literature review

PubMed Central

Merali, N.; Hussain, A.

2015-01-01

Introduction An iatrogenic caecal perforation is rare, but a serious complication associated with significant morbidity and mortality. We present a 4 min and 50 s video on a new improvisation undertaken during laparoscopic management of post-polypectomy caecal perforation. Presentation of case Our patient presented with an acute abdomen following endoscopic polypectomy. At surgery, the site of caecal perforation was close to the appendicular base with devitalization tissue, secondary to diathermy usage. The hallmark of safety within this novel technique included fresh healthy tissue margins within the endoloop (detachable snare ligation) and ensuring no ischemic tissue was gathered. Complete freeing of the appendix and meso-appendicular base was required and securing three endoloops proximal to the site of perforation. The post-operative course was uneventful. Discussion The World Society of Emergency Surgery (WSES) 2013 guidelines suggested an early laparoscopic approach is a safe and effective treatment for colonoscopy-related colonic perforation. There are no national guidelines and the management is dictated by the clinical condition of the patient, co-morbidity, size and site of perforation as well as the scale of bowel preparation, and surgical experience. Conclusion The endoloop technique described, undertaken during a laparoscopy is a novel approach. It is a simple and effective method, reminding clinicians to adapt techniques when necessary. Nevertheless, it is only limited to perforations around the appendicular base. PMID:25723744

Perforated duodenal ulcer at seven years after heart-renal transplantation: a case report.

PubMed

Naritaka, Yoshihiko; Ogawa, Kenji; Shimakawa, Takeshi; Wagatsuma, Yoshihisa; Konno, Soichi; Katsube, Takao; Miyamoto, Reiko; Hamaguchi, Kanako; Hosokawa, Toshihiko

2004-01-01

We experienced a rare case of perforated duodenal ulcer that occurred at seven years after heart-kidney transplantation. This patient is reported here together with a discussion of the etiology, the selection of treatment, and perioperative management. The patient was a 46-year-old man who presented with precordial pain. In 1995, he had undergone simultaneous heart and kidney transplantation in the United States and had been on long-term immunosuppressive and corticosteroid therapy. His precordial pain started from May 24, 2002. He was examined at our hospital on May 27 and underwent emergency surgery with a diagnosis of upper gastrointestinal perforation. A 4-mm perforation was observed on the anterior wall of the duodenal bulb and panperitonitis was also present. Patch closure of the perforation was performed by pulling the omentum over the defect. Perioperative management consisted of his usual immunosuppressants together with antacid therapy. The postoperative course was good and he was discharged on hospital day 15. In this patient, the mechanism of perforation was assumed to involve sudden irritation combined with poor circulation in the duodenum and tissue ischemia, as well as a decrease of mucosal protective factors based on long-term corticosteroid therapy. Perforated duodenal ulcer is a rare problem after heart transplantation. Because the time that elapses after perforation is an important determinant of the prognosis, early diagnosis and appropriate surgical repair are essential.

Frequency of glove perforation and the protective effect of double gloves in gynecological surgery.

PubMed

Murta, Eddie F C; Silva, Cléber S; Júnior, Odilon R A

2003-06-01

The purposes of this prospective study were to verify the frequency of glove perforation during gynecological operations and to evaluate the efficacy of double gloving in preventing damage to the inner glove. From May 2000 to May 2001, three house staff and 12 residents were asked to place their used gloves in bags labeled with the following information: procedure performed, presence of a recognized glove perforation, and role in operating team (surgeon, first or second assistant, and instrumentalist). All glove sets were tested using the method of water pression. Damaged gloves were excluded from that analysis. In all, 35 and 51 operations were utilized with single and double gloves, respectively. There were 240 single gloves and 792 double gloves tested. Perforation occurred in 10.4% of the single gloves and 9.8% of the outer double gloves. There were no cases of perforation in the inner double gloves. In cases of operating time that lasted more than 2 h, 56% of the surgeries that used single gloves had perforation vs 58.5% of the double gloves. The first assistant had the major risk for glove perforation with the use of single or double gloves. The indicator finger of the non-dominant hand was the major risk for perforation. In conclusion, we recommend double gloving in all gynecological surgery to reduce the risk of contracting blood-borne diseases.

Transparent Oxide Thin-Film Transistors: Production, Characterization and Integration

NASA Astrophysics Data System (ADS)

Barquinha, Pedro Miguel Candido

This dissertation is devoted to the study of the emerging area of transparent electronics, summarizing research work regarding the development of n-type thin-film transistors (TFTs) based on sputtered oxide semiconductors. All the materials are produced without intentional substrate heating, with annealing temperatures of only 150-200 °C being used to optimize transistor performance. The work is based on the study and optimization of active semiconductors from the gallium-indium-zinc oxide system, including both the binary compounds Ga2O3, In2O3 and ZnO, as well as ternary and quaternary oxides based on mixtures of those, such as IZO and GIZO with different atomic ratios. Several topics are explored, including the study and optimization of the oxide semiconductor thin films, their application as channel layers on TFTs and finally the implementation of the optimized processes to fabricate active matrix backplanes to be integrated in liquid crystal display (LCD) prototypes. Sputtered amorphous dielectrics with high dielectric constant (high-kappa) based on mixtures of tantalum-silicon or tantalum-aluminum oxides are also studied and used as the dielectric layers on fully transparent TFTs. These devices also include transparent and highly conducting IZO thin films as source, drain and gate electrodes. Given the flexibility of the sputtering technique, oxide semiconductors are analyzed regarding several deposition parameters, such as oxygen partial pressure and deposition pressure, as well as target composition. One of the most interesting features of multicomponent oxides such as IZO and GIZO is that, due to their unique electronic configuration and carrier transport mechanism, they allow to obtain amorphous structures with remarkable electrical properties, such as high hall-effect mobility that exceeds 60 cm2 V -1 s-1 for IZO. These properties can be easily tuned by changing the processing conditions and the atomic ratios of the multicomponent oxides, allowing to have amorphous oxides suitable to be used either as transparent semiconductors or as highly conducting electrodes. The amorphous structure, which is maintained even if the thin films are annealed at 500 °C, brings great advantages concerning interface quality and uniformity in large areas. A complete study comprising different deposition conditions of the semiconductor layer is also made regarding TFT electrical performance. Optimized devices present outstanding electrical performance, such as field-effect mobility (muFE) exceeding 20 cm2 V -1 s-1, turn-on voltage (Von) between -1 and 1 V, subthreshold slope (S) lower than 0.25 V dec-1 and On-Off ratio above 107 . Devices employing amorphous multicomponent oxides present largely improved properties when compared with the ones based on polycrystalline ZnO, mostly in terms of muFE. Within the compositional range where IZO and GIZO films are amorphous, TFT performance can be largely adjusted: for instance, high indium contents favor large mu FE but also highly negative Von, which can be compensated by proper amounts of zinc and gallium. Large oxygen concentrations during oxide semiconductor sputtering are found to be deleterious, decreasing muFE, shifting Von towards high values and turning the devices electrically unstable. It is also shown that semiconductor thickness (ds) has a very important role: for instance, by reducing ds to 10 nm it is possible to produce TFTs with Von≈0 V even using deposition conditions and/or target compositions that normally yield highly conducting films. Given the low ds of the films, this behavior is mostly related with surface states existent at the oxide semiconductor air-exposed back-surface, where depletion layers that can extend towards the dielectric/semiconductor interface are created due to the interaction with atmospheric oxygen. Different passivation layers on top of this air-exposed surface are studied, with SU-8 revealing to be to most effective one. Other important topics are source-drain contact resistance assessment and the effect of different annealing temperatures ( TA), being the properties of the TFTs dominated by TA rather than by the deposition conditions as TA increases. Fully transparent TFTs employing sputtered amorphous multicomponent dielectrics produced without intentional substrate heating present excellent electrical properties, that approach those exhibited by devices using PECVD SiO2 produced at 400 °C. Gate leakage current can be greatly reduced by using tantalum-silicon or tantalum-aluminum oxides rather than Ta2O5. A section of this dissertation is also devoted to the analysis of current stress stability and aging effects of the TFTs, being found that optimal devices exhibit recoverable threshold voltage shifts lower than 0.50 V after 24 h stress with constant drain current of 10 muA, as well as negligible aging effects during 18 months. The research work of this dissertation culminates in the fabrication of a backplane employing transparent TFTs and subsequent integration with a LCD frontplane by Hewlett-Packard. The successful operation of this initial 2.8h prototype with 128x128 pixels provides a solid demonstration that oxide semiconductor-based TFTs have the potential to largely contribute to a novel electronics era, where semiconductor materials away from conventional silicon are used to create fascinating applications, such as transparent electronic products.

Prospective study of glove perforation in obstetrical and gynecological operations: are we safe enough?

PubMed

Malhotra, Monika; Sharma, Jai Bhagwan; Wadhwa, Leena; Arora, Raksha

2004-08-01

To assess the glove perforation rate, efficacy of double gloving, effect of duration of surgery, expertise of surgeon and operative urgency on the glove perforation rate in obstetrical and gynecologic operations. From February to September 2002, double glove protocol was made necessary for all major obstetrical and gynecologic procedures. The operating surgeon, first and second assistant were included in the study. Gloves damage was noted (overt by inspection, occult by hydroinsufflation technique). Of the 156 procedures included in study, 32 procedures were performed (all emergency operations) single-gloved because surgeons found double gloving clumsy (56%), made it difficult to tie knots due to lack of dexterity (24%), or were too tight (20%). One thousand one hundred and twenty single gloves were examined after each procedure by hydroinsufflation. The overall perforation rate was 13.6% (single versus double outer gloves, 13.8% versus l3.2%, P > 0.05). Matching perforations were found in six cases (4.6%). Thus, the protection offered by double gloves was 95.4% even if the outer gloves were perforated. Four inner gloves had preexisting perforations. Sixty unused gloves checked similarly revealed a perforation rate of 1.6%. Emergency cases had higher perforation rate compared to elective surgeries (16.6% versus 10.8%, P < 0.00 1). Surgeries lasting for more than 40 min had a higher perforation rate compared to those finished in less than or equal to 40 min (18.6% versus 7.6%, P < 0.001). The middle finger of the left hand was the most commonly involved. The surgeon, first assistant and second assistant were involved in 73.6, 23.3 and 3.2% cases, respectively. Double gloving offers considerable protection against exposure to contaminants in the blood and body fluids of the patient and should be made routine, especially in developing countries where HIV, hepatitis B and C are widely prevalent. Double gloving should be made mandatory in emergency procedures, which have a higher perforation rate due to operative urgency, and gloves should be changed in operations lasting for more than 40 min to ensure integrity of barrier.

Computed tomography assessment of lateral pedicle wall perforation by free-hand subaxial cervical pedicle screw placement.

PubMed

Wang, Yingsong; Xie, Jingming; Yang, Zhendong; Zhao, Zhi; Zhang, Ying; Li, Tao; Liu, Luping

2013-07-01

To present the technique of free-hand subaxial cervical pedicle screw (CPS) placement without using intra-operative navigating devices, and to investigate the crucial factors for safe placement and avoidance of lateral pedicle wall perforation, by measuring and classifying perforations with postoperative computed tomography (CT) scan. The placement of CPS has generally been considered as technically demanding and associated with considerable lateral wall perforation rate. For surgeons without access to navigation systems, experience of safe free-hand technique for subaxial CPS placement is especially valuable. A total of 214 consecutive traumatic or degenerative patients with 1,024 CPS placement using the free-hand technique were enrolled. In the operative process, the lateral mass surface was decorticated. Then a small curette was used to identify the pedicle entrance by touching the cortical bone of the medial pedicle wall. It was crucial to keep the transverse angle and make appropriate adjustment with guidance of the resistance of the thick medial cortical bone. The hand drill should be redirected once soft tissue breach was palpated by a slim ball-tip prober. With proper trajectory, tapping, repeated palpation, the 26-30 mm screw could be placed. After the procedure, the transverse angle of CPS trajectory was measured, and perforation of the lateral wall was classified by CT scan: grade 1, perforation of pedicle wall by screw placement, with the external edge of screw deviating out of the lateral pedicle wall equal to or less than 2 mm and grade 2, critical perforation of pedicle wall by screw placement, large than 2 mm. A total of 129 screws (12.64 %) were demonstrated as lateral pedicle wall perforation, of which 101 screws (9.86 %) were classified as grade 1, whereas 28 screws (2.73 %) as grade 2. Among the segments involved, C3 showed an obviously higher perforating rate than other (P < 0.05). The difference between the anatomical pedicle transverse angle and the screw trajectory angle was higher in patients of grade 2 perforation than the others. In the 28 screws of grade 2 perforation verified by axial CT, 26 screws had been palpated as abnormal during operation. However, only 19 out of the 101 screws of grade 1 perforation had shown palpation alarming signs during operation. The average follow-up was 36.8 months (range 5-65 months). There was no symptom and sign of neurovascular injuries. Two screws (0.20 %) were broken, and one screw (0.10 %) loosen. Placement of screw through a correct trajectory may lead to grade 1 perforation, which suggests transversal expansion and breakage of the thinner lateral cortex, probably caused by mismatching of the diameter of 3.5 mm screws and the tiny cancellous bone cavity of pedicle. Grade 1 perforation is deemed as relatively safe to the vertebral artery. Grade 2 perforation means obvious deviation of the trajectory angle of hand drill, which directly penetrates into the transverse foramen, and the risk of vertebral artery injury (VAI) or development of thrombi caused by the irregular blood flow would be much greater compared to grade 1 perforation. Moreover, there are two crucial maneuvers for increasing accuracy of screw placement: identifying the precise entry point using a curette or hand drill to touch the true entrance of the canal after decortication, and guiding CPS trajectory on axial plane by the resistant of thick medial wall.

A method of sealing perforated sinus membrane and histologic finding of bone substitutes: a case report.

PubMed

Shin, Hong-In; Sohn, Dong-Seok

2005-12-01

To augment the atrophic posterior maxilla, a sinus bone graft has been widely used for sinus floor augmentation. Various bone substitutes have been developed and grafted in the maxillary sinus with and without membranes perforation, although autogenous bone is recommended as a gold standard of grafting materials. Membrane perforation is the most common complication associated with sinus bone graft. To repair a perforation, various methods have been developed. This case report is focused on histologic findings of 1 bovine hydroxyapatite (Bio-Oss; Geistlich Pharma AG, Wolhusen, Switzerland) and 2 kinds of human mineral allograft- Tutoplast cancellous microchips (TutoGen Medical GmbH, Neunkirchen am. Brand Germany), and irradiated allogeniccancellous bone and marrow (ICB; Rocky Mountain Tissue Bank, Aurora, CO) used for sinus graft in the same patient with membrane perforation after various healing periods. Mineral allograft showed favorable new bone regeneration with the repair of membrane perforation. This case report also describes a technique regarding how to repair completely perforated sinus membrane after the removal of a mucocele using human collagen membrane (Tutoplast pericardium; TutoGen Medical GmbH) and fibrin adhesive (Greenplast; Green Cross Co., Youngin, Korea) to stabilize collagen membrane.

Methods for Solving Gas Damping Problems in Perforated Microstructures Using a 2D Finite-Element Solver

PubMed Central

Veijola, Timo; Råback, Peter

2007-01-01

We present a straightforward method to solve gas damping problems for perforated structures in two dimensions (2D) utilising a Perforation Profile Reynolds (PPR) solver. The PPR equation is an extended Reynolds equation that includes additional terms modelling the leakage flow through the perforations, and variable diffusivity and compressibility profiles. The solution method consists of two phases: 1) determination of the specific admittance profile and relative diffusivity (and relative compressibility) profiles due to the perforation, and 2) solution of the PPR equation with a FEM solver in 2D. Rarefied gas corrections in the slip-flow region are also included. Analytic profiles for circular and square holes with slip conditions are presented in the paper. To verify the method, square perforated dampers with 16–64 holes were simulated with a three-dimensional (3D) Navier-Stokes solver, a homogenised extended Reynolds solver, and a 2D PPR solver. Cases for both translational (in normal to the surfaces) and torsional motion were simulated. The presented method extends the region of accurate simulation of perforated structures to cases where the homogenisation method is inaccurate and the full 3D Navier-Stokes simulation is too time-consuming.

Augmented reality and dynamic infrared thermography for perforator mapping in the anterolateral thigh.

PubMed

Cifuentes, Ignacio Javier; Dagnino, Bruno Leonardo; Salisbury, María Carolina; Perez, María Eliana; Ortega, Claudia; Maldonado, Daniela

2018-05-01

Dynamic infrared thermography (DIRT) has been used for the preoperative mapping of cutaneous perforators. This technique has shown a positive correlation with intraoperative findings. Our aim was to evaluate the accuracy of perforator mapping with DIRT and augmented reality using a portable projector. For this purpose, three volunteers had both of their anterolateral thighs assessed for the presence and location of cutaneous perforators using DIRT. The obtained image of these "hotspots" was projected back onto the thigh and the presence of Doppler signals within a 10-cm diameter from the midpoint between the lateral patella and the anterior superior iliac spine was assessed using a handheld Doppler device. Hotspots were identified in all six anterolateral thighs and were successfully projected onto the skin. The median number of perforators identified within the area of interest was 5 (range, 3-8) and the median time needed to identify them was 3.5 minutes (range, 3.3-4.0 minutes). Every hotspot was correlated to a Doppler sound signal. In conclusion, augmented reality can be a reliable method for transferring the location of perforators identified by DIRT onto the thigh, facilitating its assessment and yielding a reliable map of potential perforators for flap raising.

Fatigue response of perforated titanium for application in laminar flow control

NASA Technical Reports Server (NTRS)

Johnson, W. Steven; Miller, Jennifer L.; Newman, Jr., James

1996-01-01

The room temperature tensile and fatigue response of non-perforated and perforated titanium for laminar flow control application was investigated both experimentally and analytically. Results showed that multiple perforations did not affect the tensile response, but did reduce the fatigue life. A two dimensional finite element stress analysis was used to determine that the stress fields from adjacent perforations did not influence one another. The stress fields around the holes did not overlap one another, allowing the materials to be modeled as a plate with a center hole. Fatigue life was predicted using an equivalent MW flow size approach to relate the experimental results to microstructural features of the titanium. Predictions using flaw sizes ranging from 1 to 15 microns correlated within a factor of 2 with the experimental results by using a flow stress of 260 MPa. By using two different flow stresses in the crack closure model and correcting for plasticity, the experimental results were bounded by the predictions for high applied stresses. Further analysis of the complex geometry of the perforations and the local material chemistry is needed to further understand the fatigue behavior of the perforated titanium.

Hollow organ perforation in blunt abdominal trauma: the role of diagnostic peritoneal lavage.

PubMed

Wang, Yu-Chun; Hsieh, Chi-Hsun; Fu, Chih-Yuan; Yeh, Chun-Chieh; Wu, Shih-Chi; Chen, Ray-Jade

2012-05-01

With recent advances in radiologic diagnostic procedures, the use of diagnostic peritoneal lavage (DPL) has markedly declined. In this study, we reviewed data to reevaluate the role of DPL in the diagnosis of hollow organ perforation in patients with blunt abdominal trauma. Adult patients who had sustained blunt abdominal trauma and who were hemodynamically stable after initial resuscitation underwent an abdominal computed tomographic (CT) scan. Diagnostic peritoneal lavage was performed for patients who were indicated to receive nonoperative management and where hollow organ perforation could not be ruled out. During a 60-month period, 64 patients who had received abdominal CT scanning underwent DPL. Nineteen patients were diagnosed as having a positive DPL based on cell count ratio of 1 or higher. There were 4 patients who sustained small bowel perforation. The sensitivity and specificity of the cell count ratio for a hollow organ perforation in this study were 100% and 75%, respectively. No missed hollow organ perforations were detected. For patients with blunt abdominal trauma and hemoperitoneum who plan to receive nonoperative management, DPL is still a useful tool to exclude hollow organ perforation that is undetected by CT. Copyright © 2012 Elsevier Inc. All rights reserved.

Perforated peptic ulcer following gastric bypass for obesity.

PubMed

Macgregor, A M; Pickens, N E; Thoburn, E K

1999-03-01

Peptic ulcer in the excluded segment of a gastric bypass performed in the management of morbid obesity has only rarely been reported in the literature. The purpose of this study is to review our experience with the condition in a series of 4300 patients who underwent gastric-restrictive surgery between 1978 and 1997. Eleven patients presented with acute perforation of a peptic ulcer in the excluded gastric segment. Nine ulcers were duodenal, one was gastric, and one patient had both gastric and duodenal perforations. The time between primary gastric-restrictive surgery and ulcer perforation varied from 20 days to 12 years. All patients presented with upper abdominal pain. The classical radiological sign of perforated peptic ulcer, free air under the diaphragm, did not occur in any patient. Nine patients were initially treated by primary closure of the perforation with subsequent definitive ulcer therapy by vagotomy, pyloroplasty, or gastrectomy. One case, initially treated elsewhere, was managed by placement of a Malecot catheter through the duodenal perforation, gastrostomy, and peritoneal drainage. One recent case remains symptom-free on H2 blockers after simple closure. There was no mortality. Six cases were previously reported in the literature with a 33 per cent mortality rate.

Perforating Thin Metal Sheets

NASA Technical Reports Server (NTRS)

Davidson, M. E.

1985-01-01

Sheets only few mils thick bonded together, punched, then debonded. Three-step process yields perforated sheets of metal. (1): Individual sheets bonded together to form laminate. (2): laminate perforated in desired geometric pattern. (3): After baking, laminate separates into individual sheets. Developed for fabricating conductive layer on blankets that collect and remove ions; however, perforated foils have other applications - as conductive surfaces on insulating materials; stiffeners and conductors in plastic laminates; reflectors in antenna dishes; supports for thermal blankets; lightweight grille cover materials; and material for mockup of components.

Pre-operative CT angiography and three-dimensional image post processing for deep inferior epigastric perforator flap breast reconstructive surgery.

PubMed

Lam, D L; Mitsumori, L M; Neligan, P C; Warren, B H; Shuman, W P; Dubinsky, T J

2012-12-01

Autologous breast reconstructive surgery with deep inferior epigastric artery (DIEA) perforator flaps has become the mainstay for breast reconstructive surgery. CT angiography and three-dimensional image post processing can depict the number, size, course and location of the DIEA perforating arteries for the pre-operative selection of the best artery to use for the tissue flap. Knowledge of the location and selection of the optimal perforating artery shortens operative times and decreases patient morbidity.

Iatrogenic perforation of perivaterian duodenal diverticulum: report of a case

PubMed Central

Cavanagh, James E.

1996-01-01

The author reports a case of iatrogenic perforation of a duodenal diverticulum, an extremely rare occurrence, during percutaneous radiologic extraction of a retained common-bile-duct stone. Perforation was related to the perivaterian location of the duodenal diverticulum. Because an inflammatory reaction was present, tube duodenostomy was chosen over excision, closure and drainage to prevent the complication of lateral duodenal fistula and sepsis. Whenever iatrogenic duodenal perforation is suspected, prompt radiologic documentation and early surgical consultation should be sought. PMID:8697327

Processor architectures utilizing magnetic bubble and semi-conductor memories. [for the Omega navigation system

NASA Technical Reports Server (NTRS)

Parrish, E. A., Jr.; Aylor, J. H.

1975-01-01

To aid work being conducted on the feasibility of a low cost Omega navigational receiver, a control panel was designed and constructed according to supplied specifications. Since the proposed Omega receiver is designed around a microprocessor, software engineering necessary for control panel operation is included in the design. The control panel is to be used as an operational model for use in the design of a prototype receiver. A detailed description of the hardware design is presented along with a description of the software needed to operate the panel. A complete description of the operating procedures for the panel are also included.

Associative Pattern Recognition In Analog VLSI Circuits

NASA Technical Reports Server (NTRS)

Tawel, Raoul

1995-01-01

Winner-take-all circuit selects best-match stored pattern. Prototype cascadable very-large-scale integrated (VLSI) circuit chips built and tested to demonstrate concept of electronic associative pattern recognition. Based on low-power, sub-threshold analog complementary oxide/semiconductor (CMOS) VLSI circuitry, each chip can store 128 sets (vectors) of 16 analog values (vector components), vectors representing known patterns as diverse as spectra, histograms, graphs, or brightnesses of pixels in images. Chips exploit parallel nature of vector quantization architecture to implement highly parallel processing in relatively simple computational cells. Through collective action, cells classify input pattern in fraction of microsecond while consuming power of few microwatts.

Diagnostic accuracy of cone-beam computed tomography scans with high- and low-resolution modes for the detection of root perforations.

PubMed

Shokri, Abbas; Eskandarloo, Amir; Norouzi, Marouf; Poorolajal, Jalal; Majidi, Gelareh; Aliyaly, Alireza

2018-03-01

This study compared the diagnostic accuracy of cone-beam computed tomography (CBCT) scans obtained with 2 CBCT systems with high- and low-resolution modes for the detection of root perforations in endodontically treated mandibular molars. The root canals of 72 mandibular molars were cleaned and shaped. Perforations measuring 0.2, 0.3, and 0.4 mm in diameter were created at the furcation area of 48 roots, simulating strip perforations, or on the external surfaces of 48 roots, simulating root perforations. Forty-eight roots remained intact (control group). The roots were filled using gutta-percha (Gapadent, Tianjin, China) and AH26 sealer (Dentsply Maillefer, Ballaigues, Switzerland). The CBCT scans were obtained using the NewTom 3G (QR srl, Verona, Italy) and Cranex 3D (Soredex, Helsinki, Finland) CBCT systems in high- and low-resolution modes, and were evaluated by 2 observers. The chi-square test was used to assess the nominal variables. In strip perforations, the accuracies of low- and high-resolution modes were 75% and 83% for NewTom 3G and 67% and 69% for Cranex 3D. In root perforations, the accuracies of low- and high-resolution modes were 79% and 83% for NewTom 3G and was 56% and 73% for Cranex 3D. The accuracy of the 2 CBCT systems was different for the detection of strip and root perforations. The Cranex 3D had non-significantly higher accuracy than the NewTom 3G. In both scanners, the high-resolution mode yielded significantly higher accuracy than the low-resolution mode. The diagnostic accuracy of CBCT scans was not affected by the perforation diameter.

Perforator chimerism for the reconstruction of complex defects: A new chimeric free flap classification system.

PubMed

Kim, Jeong Tae; Kim, Youn Hwan; Ghanem, Ali M

2015-11-01

Complex defects present structural and functional challenges to reconstructive surgeons. When compared to multiple free flaps or staged reconstruction, the use of chimeric flaps to reconstruct such defects have many advantages such as reduced number of operative procedures and donor site morbidity as well as preservation of recipient vessels. With increased popularity of perforator flaps, chimeric flaps' harvest and design has benefited from 'perforator concept' towards more versatile and better reconstruction solutions. This article discusses perforator based chimeric flaps and presents a practice based classification system that incorporates the perforator flap concept into "Perforator Chimerism". The authors analyzed a variety of chimeric patterns used in 31 consecutive cases to present illustrative case series and their new classification system. Accordingly, chimeric flaps are classified into four types. Type I: Classical Chimerism, Type II: Anastomotic Chimerism, Type III: Perforator Chimerism and Type IV Mixed Chimerism. Types I on specific source vessel anatomy whilst Type II requires microvascular anastomosis to create the chimeric reconstructive solution. Type III chimeric flaps utilizes the perforator concept to raise two components of tissues without microvascular anastomosis between them. Type IV chimeric flaps are mixed type flaps comprising any combination of Types I to III. Incorporation of the perforator concept in planning and designing chimeric flaps has allowed safe, effective and aesthetically superior reconstruction of complex defects. The new classification system aids reconstructive surgeons and trainees to understand chimeric flaps design, facilitating effective incorporation of this important reconstructive technique into the armamentarium of the reconstruction toolbox. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Non-ossicular signal transmission in human middle ears: Experimental assessment of the “acoustic route” with perforated tympanic membranes

PubMed Central

Voss, Susan E.; Rosowski, John J.; Merchant, Saumil N.; Peake, William T.

2008-01-01

Direct acoustic stimulation of the cochlea by the sound-pressure difference between the oval and round windows (called the “acoustic route”) has been thought to contribute to hearing in some pathological conditions, along with the normally dominant “ossicular route.” To determine the efficacy of this acoustic route and its constituent mechanisms in human ears, sound pressures were measured at three locations in cadaveric temporal bones [with intact and perforated tympanic membranes (TMs)]: (1) in the external ear canal lateral to the TM, PTM; (2) in the tympanic cavity lateral to the oval window, POW; and (3) near the round window, PRW. Sound transmission via the acoustic route is described by two concatenated processes: (1) coupling of sound pressure from ear canal to middle-ear cavity, HPCAV≡PCAV/PTM, where PCAV represents the middle-ear cavity pressure, and (2) sound-pressure difference between the windows, HWPD≡(POW−PRW)/PCAV. Results show that: HPCAV depends on perforation size but not perforation location; HWPD depends on neither perforation size nor location. The results (1) provide a description of the window pressures based on measurements, (2) refute the common otological view that TM perforation location affects the “relative phase of the pressures at the oval and round windows,” and (3) show with an intact ossicular chain that acoustic-route transmission is substantially below ossicular-route transmission except for low frequencies with large perforations. Thus, hearing loss from TM perforations results primarily from reduction in sound coupling via the ossicular route. Some features of the frequency dependence of HPCAV and HWPD can be interpreted in terms of a structure-based lumped-element acoustic model of the perforation and middle-ear cavities. PMID:17902851

Predictors of appendiceal perforation in an equal access system.

PubMed

Walker, Avery; Hatch, Quinton; Drake, Thurston; Nelson, Daniel W; Fitzpatrick, Emilie; Bingham, Jason; Black, George; Maykel, Justin A; Steele, Scott R

2014-07-01

Discrepancies in socioeconomic factors have been associated with higher rates of perforated appendicitis. As an equal-access health care system theoretically removes these barriers, we aimed to determine if remaining differences in demographics, education, and pay result in disparate outcomes in the rate of perforated appendicitis. All patients undergoing appendectomy for acute appendicitis (November 2004-October 2009) at a tertiary care equal access institution were categorized by demographics and perioperative data. Rank of the sponsor was used as a surrogate for economic status. A multivariate logistic regression model was performed to determine patient and clinical characteristics associated with perforated appendicitis. A total of 680 patients (mean age 30±16 y; 37% female) were included. The majority were Caucasian (56.4% [n=384]; African Americans 5.6% [n=38]; Asians 1.9% [n=13]; and other 48.9% [n=245]) and enlisted (87.2%). Overall, 6.4% presented with perforation, with rates of 6.6%, 5.8%, and 6.7% (P=0.96) for officers, enlisted soldiers, and contractors, respectively. There was no difference in perforation when stratified by junior or senior status for either officers or enlisted (9.3% junior versus 4.40% senior officers, P=0.273; 6.60% junior versus 5.50% senior enlisted, P=0.369). On multivariate analysis, parameters such as leukocytosis and temperature, as well as race and rank were not associated with perforation (P=0.7). Only age had a correlation, with individuals aged 66-75 y having higher perforation rates (odds ratio, 1.04; 95% confidence interval, 1.02-1.05; P<0.001). In an equal-access health care system, older age, not socioeconomic factors, correlated with increased appendiceal perforation rates. Published by Elsevier Inc.

Candidiasis, A Rare Cause of Gastric Perforation: A Case Report and Review of Literature

PubMed Central

Ukekwe, FI; Nwajiobi, C; Agbo, MO; Ebede, SO; Eni, AO

2015-01-01

Fungi are unusually rare causes of gastric perforation, with most cases of gastric perforation occurring as complications of peptic ulcer disease (PUD), nonsteroidal anti-inflammatory drugs (NSAIDs) and gastric neoplasms. Here, we report the case of a 70-year-old Nigerian male who presented with severe epigastric pain, with no associated history of PUD, NSAIDs use or gastric neoplasm. An emergency exploratory laparotomy was performed and a gastric perforation was discovered and repaired. Histopathological examination of the gastric perforation edge biopsy revealed an intense Candida growth consisting of numerous fungal spores and hyphae invading and destroying the gastric wall. He was subsequently treated with fluconazole antifungal and discharged home after an uneventful postoperative period. PMID:26229723

Candidiasis, A Rare Cause of Gastric Perforation: A Case Report and Review of Literature.

PubMed

Ukekwe, F I; Nwajiobi, C; Agbo, M O; Ebede, S O; Eni, A O

2015-01-01

Fungi are unusually rare causes of gastric perforation, with most cases of gastric perforation occurring as complications of peptic ulcer disease (PUD), nonsteroidal anti-inflammatory drugs (NSAIDs) and gastric neoplasms. Here, we report the case of a 70-year-old Nigerian male who presented with severe epigastric pain, with no associated history of PUD, NSAIDs use or gastric neoplasm. An emergency exploratory laparotomy was performed and a gastric perforation was discovered and repaired. Histopathological examination of the gastric perforation edge biopsy revealed an intense Candida growth consisting of numerous fungal spores and hyphae invading and destroying the gastric wall. He was subsequently treated with fluconazole antifungal and discharged home after an uneventful postoperative period.

Bayesian characterization of micro-perforated panels and multi-layer absorbers

NASA Astrophysics Data System (ADS)

Schmitt, Andrew Alexander Joseph

First described by the late acoustician Dah-You Maa, micro-perforated panel (MPP) absorbers produce extremely high acoustic absorption coefficients. This is done without the use of conventional fibrous or porous materials that are often used in acoustic treatments, meaning MPP absorbers are capable of being implemented and withstanding critical situations where traditional absorbers do not suffice. The absorption function of a micro-perforated panel yields high yet relatively narrow results at certain frequencies, although wide-band absorption can be designed by stacking multiple MPP absorbers comprised of different characteristic parameters. Using Bayesian analysis, the physical properties of panel thickness, pore diameter, perforation ratio, and air depth are estimated inversely from experimental data of acoustic absorption, based on theoretical models for design of micro-perforated panels. Furthermore, this analysis helps to understand the interdependence and uncertainties of the parameters and how each affects the performance of the panel. Various micro-perforated panels are manufactured and tested in single- and double-layer absorber constructions.

Comparison of Thermal Performances between Low Porosity Perforate Plate and Flat Plate Solar Air Collector

NASA Astrophysics Data System (ADS)

Chan, Hoy-Yen; Vinson, A. A.; Baljit, S. S. S.; Ruslan, M. H.

2018-04-01

Flat plate solar air collector is the most common collector design, which is relatively simpler to fabricate and lower cost. In the present study, perforated plate solar collector was developed to improve the system thermal performance. A glazed perforated plate of 6mm holes diameter with square geometry was designed and installed as the absorber of the collector. The influences of solar radiation intensity and mass flow rate on the thermal performance were investigated. The perforated collector was compared with the flat plate solar collector under the same operating conditions. The highest values of thermal efficiency in this study for the perforated plate (PP) and the flat plate (FP) solar collectors were 59% and 36% respectively, at solar radiation intensity of 846 Wm-2 and mass flow rate of 0.02 kgs-1. Furthermore, PP collector gave better thermal performance compared to FP collector; and compared to previous studies, the present perforated design was compatible with the flat plate with double pass designs.

Liver Parenchyma Perforation following Endoscopic Retrograde Cholangiopancreatography.

PubMed

Kayashima, Hiroto; Ikegami, Toru; Kasagi, Yuta; Hidaka, Gen; Yamazaki, Koji; Sadanaga, Noriaki; Itoh, Hiroyuki; Emi, Yasunori; Matsuura, Hiroshi; Okadome, Kenichiro

2011-05-01

Although endoscopic retrograde cholangiopancreatography (ERCP) is an effective modality for the diagnosis and treatment of biliary and pancreatic diseases, it is still related with several severe complications. We report on the case of a female patient who developed liver parenchyma perforation following ERCP. She underwent ERCP with sphincterotomy and extraction of a common bile duct stone. Shortly after ERCP, abdominal distension was identified. Abdominal computed tomography revealed intraabdominal air leakage and leakage of contrast dye penetrating the liver parenchyma into the space around the spleen. Since periampullary perforation related to sphincterotomy could not be denied, she was referred for immediate surgery. Obvious perforation could not be found at surgery. Cholecystectomy, insertion of a T tube into the common bile duct, placement of a duodenostomy tube and drainage of the retroperitoneum were performed. She did well postoperatively and was discharged home on postoperative day 28. In conclusion, as it is well recognized that perforation is one of the most serious complication related to ERCP, liver parenchyma perforation should be suspected as a cause.

Evolution of imaging for abdominal perforation

PubMed Central

Singh, JP; Steward, MJ; Booth, TC; Mukhtar, H; Murray, D

2010-01-01

INTRODUCTION Gastrointestinal (GI) perforation is a common surgical presentation. In recent years, computed tomography (CT) has been shown to be accurate for predicting the site of GI perforation, and has become the investigation of choice. However the signs may be subtle or only indirectly related to the site or aetiology of perforation. SUBJECTS AND METHODS A MEDLINE and PubMed search was performed for journals before June 2009 with MeSH major terms ‘CT’ and ‘perforation’. Non-English speaking literature was excluded. RESULTS Examples of GI perforation of various aetiologies are reviewed (inflammatory, neoplastic, traumatic and iatrogenic) high-lighting characteristic CT appearances as well as pitfalls in diagnosis. Features of perforation include the presence of free gas or fluid within the supra- and/or inframesocolic compartments, segmental bowel wall thickening, bowel wall discontinuity, stranding of the mesenteric fat and abscess formation. CONCLUSIONS These differentiating features facilitate accurate multidisciplinary pre-operative evaluation, necessary to plan patient management and potential surgical approach. PMID:20412668

Management of necrotising appendicitis associated with widespread necrotising enterocolitis of the small and large bowel and perforated duodenal ulcer.

PubMed

Gupta, Vaibhav; Zani, Augusto; Jackson, Paul; Singh, Shailinder

2015-06-08

A 7-year-old boy presented in septic shock secondary to appendicitis with generalised peritonitis. Following crystalloid resuscitation, he underwent surgery. Faecopurulent contamination and free air were found. This was secondary to a perforated and gangrenous appendix, multiple large and small bowel segments with perforations, patches of necrosis, interspersed with healthy bowel and segments of questionable viability. There was also a perforated duodenal ulcer. Necrotic segments were resected using a 'clip-and-drop' technique to shorten operative duration and guide resection to preserve bowel length. After six laparotomies and multiple bowel resections, the child was discharged home with an ileostomy that was subsequently reversed. He is currently on a normal diet and pursuing all activities appropriate for his age. Perforated appendicitis can be associated with widespread bowel necrosis and multiple perforations. A conservative damage limitation approach using the 'clip-and-drop' technique and relook laparotomies is useful in the management of extensive bowel necrosis in children. 2015 BMJ Publishing Group Ltd.

Ten-Year Experience of Managing Giant Duodenal Ulcer Perforations with Triple Tube Ostomy at Tertiary Hospital of North India.

PubMed

Ali, Wasif Mohammad; Ansari, M M; Rizvi, Syed Amjad Ali; Rabb, A Z; Mansoor, Tariq; Harris, Syed Hassan; Akhtar, Mohd Sadiq

2018-02-01

Duodenal ulcer perforations have been known since 1600 AD. It is a common surgical emergency and every surgeon will encounter it. The perforation size of >2 cm has been used as the criteria for defining Giant duodenal ulcers. The management of giant duodenal perforations in hemodynamically unstable patient with comorbid condition is taxing because of high incidence of the postoperative leak and mortality. We have used the simple technique of Triple Tube Ostomy after the primary closure of the defect with encouraging results. It is a retrospective study done at the J. N medical college AMU Aligarh from May 2005 to May 2015. Hemodynamically unstable patients who have presented to the emergency with preoperative diagnoses of giant duodenal ulcer perforation and had undergone triple tube ostomy with primary repair of the perforation were included in the study. There were 34 patients of giant duodenal perforation who presented in shock. All of them underwent triple-tube-ostomy after primary repair of the duodenum. Thirty-two patients recovered with two mortalities (5.8 %). Several definite surgical techniques have been described for the management of giant duodenal ulcer perforation but they are complex, have very high morbidity and mortality rate and require an expert surgeon. A close retrospective scrutiny of the patients suggests that simple triple-tube-ostomy technique which is based on the principle of damage control surgery has good postoperative results Therefore, we recommend it as the procedure of choice in these patients.

The incidence of maxillary sinus membrane perforation during endoscopically assessed crestal sinus floor elevation: a pilot study.

PubMed

Garbacea, Antoanela; Lozada, Jaime L; Church, Christopher A; Al-Ardah, Aladdin J; Seiberling, Kristin A; Naylor, W Patrick; Chen, Jung-Wei

2012-08-01

Transcrestal sinus membrane elevation is a surgical procedure performed to increase the bone volume in the maxillary sinus cavity. Because of visual limitations, the potential for maxillary sinus membrane perforations may be greater than with the lateral approach technique. The aim of this study was to macroscopically investigate ex vivo the occurrence of sinus membrane perforation during surgery using 3 transcrestal sinus floor elevation methods. Twenty fresh human cadaver heads, with 40 intact sinuses, were used for simultaneous sinus membrane elevation, placement of graft material, and dental implants. Real-time sinus endoscopy, periapical digital radiographs, and cone-beam computerized tomography (CBCT) images were subsequently used to evaluate the outcome of each surgical procedure. Perforation rates for each of the 3 techniques were then compared using a significance level of P < .05. No statistically significant differences in the perforation rate (P = .79) were found among the 3 surgical techniques. Although the sinus endoscope noted a higher frequency of perforations at the time of implant placement as compared with instrumentation or graft insertion, the difference was not statistically significant (P = .04). The CBCT readings were judged to be more accurate for identifying evidence of sinus perforations than the periapical radiographs when compared with the direct visualization with the endoscope. This pilot study demonstrated that a sinus membrane perforation can occur at any time during the sinus lift procedure, independent of the surgical method used.

Mortality risk factor analysis in colonic perforation: would retroperitoneal contamination increase mortality in colonic perforation?

PubMed

Yoo, Ri Na; Kye, Bong-Hyeon; Kim, Gun; Kim, Hyung Jin; Cho, Hyeon-Min

2017-10-01

Colonic perforation is a lethal condition presenting high morbidity and mortality in spite of urgent surgical treatment. This study investigated the surgical outcome of patients with colonic perforation associated with retroperitoneal contamination. Retrospective analysis was performed for 30 patients diagnosed with colonic perforation caused by either inflammation or ischemia who underwent urgent surgical treatment in our facility from January 2005 to December 2014. Patient characteristics were analyzed to find risk factors correlated with increased postoperative mortality. Using the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM) audit system, the mortality and morbidity rates were estimated to verify the surgical outcomes. Patients with retroperitoneal contamination, defined by the presence of retroperitoneal air in the preoperative abdominopelvic CT, were compared to those without retroperitoneal contamination. Eight out of 30 patients (26.7%) with colonic perforation had died after urgent surgical treatment. Factors associated with mortality included age, American Society of Anesthesiologists (ASA) physical status classification, and the ischemic cause of colonic perforation. Three out of 6 patients (50%) who presented retroperitoneal contamination were deceased. Although the patients with retroperitoneal contamination did not show significant increase in the mortality rate, they showed significantly higher ASA physical status classification than those without retroperitoneal contamination. The mortality rate predicted from Portsmouth POSSUM was higher in the patients with retroperitoneal contamination. Patients presenting colonic perforation along with retroperitoneal contamination demonstrated severe comorbidity. However, retroperitoneal contamination was not found to be correlated with the mortality rate.

Increased risk of cardiovascular perforation during ECMO with a bicaval, wire-reinforced cannula.

PubMed

Johnson, Sidney M; Itoga, Nathan; Garnett, Gwendolyn M; Kilcommons, Melody; Puapong, Devin P; Woo, Russell K

2014-01-01

Cardiac or major vascular perforation is a rare but serious risk of ECMO. We sought to determine if perforation rates are related to cannula design. We utilized three methods to evaluate perforation on ECMO. 1. The ELSO registry was queried to establish the historical rate of hemorrhagic pericardial tamponade. 2. ELSO centers were surveyed regarding cannula related perforation events and brands of cannulas used over a four year time period (January 2008-March 2012). 3. The FDA's MAUDE database was reviewed looking for adverse events related to ECMO cannulas. The historical rate of hemorrhagic pericardial tamponade in the ELSO registry was 0.53% (~1985-2010, ELSO registry). In the survey there were eleven reports of cannula-related perforation, 0.74% (11/1482 p-value=0.29) at 7 different ELSO centers with 23 ELSO centers responding (17% response rate). The incidence of perforation was much higher for the wire-reinforced bicaval design 3.6% (10/279) as compared to catheters designed for the atrial position, 0.1% (1/1203, p-value<0.0001). Review of the FDA's MAUDE database revealed 19 adverse events related to the bicaval cannula design, 16 of which were hemorrhagic pericardial effusions or tamponade. These findings suggest a relatively high rate of cardiac perforation associated with the dual lumen bicaval cannula. This may be related to inherent differences in cannula design or the IVC positioning required by the design. © 2014.

Accuracy of CT chest without oral contrast for ruling out esophageal perforation using fluoroscopic esophagography as reference standard: a retrospective study.

PubMed

Awais, Muhammad; Qamar, Saqib; Rehman, Abdul; Baloch, Noor Ul-Ain; Shafqat, Gulnaz

2018-02-26

Esophageal perforation has a high mortality rate. Fluoroscopic esophagography (FE) is the procedure of choice for diagnosing esophageal perforation. However, FE can be difficult to perform in seriously ill patients. We retrospectively reviewed charts and scans of all patients who had undergone thoracic CT (TCT) without oral contrast and FE for suspicion of esophageal perforation at our hospital between October, 2010 and December, 2015. Scans were interpreted by a single consultant radiologist having > 5 years of relevant experience. Statistical analysis was performed using SPSS version 20. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of TCT were computed using FE as reference standard. Of 122 subjects, 106 (83%) were male and their median age was 42 [inter-quartile range (IQR) 29-53] years. Esophageal perforation was evident on FE in 15 (8%) cases. Sensitivity, specificity, PPV and NPV of TCT for detecting esophageal perforation were 100, 54.6, 23.4 and 100%, respectively. When TCT was negative (n = 107), an alternative diagnosis was evident in 65 cases. Thoracic computed tomography (TCT) had 100% sensitivity and negative predictive value for excluding esophageal perforation. FE may be omitted in patients who have no evidence of mediastinal collection, pneumomediastinum or esophageal wall defect on TCT. However, in the presence of any of these features, FE is still necessary to confirm or exclude the presence of an esophageal perforation.

Bowel perforation in type IV vascular Ehlers-Danlos syndrome. A systematic review.

PubMed

El Masri, H; Loong, T-H; Meurette, G; Podevin, J; Zinzindohoue, F; Lehur, P-A

2018-05-01

Spontaneous gastrointestinal (GI) perforation is a well-known complication occurring in patients suffering from Type IV vascular Ehlers-Danlos syndrome (EDS IV). The aim of the present study was to review the current literature on spontaneous GI perforation in EDS IV and illustrate the surgical management and outcome when possible. A systematic review of all the published data on EDS IV patients with spontaneous GI perforation between January 2000 and December 2015 was conducted using three major databases PUBMED, EMBASE, and Cochrane Central Register of Controlled Trails. References of the selected articles were screened to avoid missing main articles. Twenty-seven published case reports and four retrospective studies, including 31 and 527 cases, respectively, matched the search criteria. A case from our institution was added. Mean age was 26 years (range 6-64 years). The most frequent site of perforation was the colon, particularly the sigmoid, followed by small bowel, upper rectum, and finally stomach. The majority of cases were initially managed with Hartmann's procedure. In recurrent perforations, total colectomy was performed. The reperforation rate was considerably higher in the "partial colectomy with anastomosis" group than in the Hartmann group. Colonic perforation is the most common spontaneous GI perforation in EDS IV patients. An unexpected fragility of the tissues should raise the possibility of a connective tissue disorder and prompt further investigation with eventual management of these high-risk patients with a multidisciplinary team approach in dedicated centres. In the emergency setting, a Hartmann procedure should be performed.

Scalariform-to-simple transition in vessel perforation plates triggered by differences in climate during the evolution of Adoxaceae

PubMed Central

Lens, Frederic; Vos, Rutger A.; Charrier, Guillaume; van der Niet, Timo; Merckx, Vincent; Baas, Pieter; Aguirre Gutierrez, Jesus; Jacobs, Bart; Chacon Dória, Larissa; Smets, Erik; Delzon, Sylvain; Janssens, Steven B.

2016-01-01

Background and Aims Angiosperms with simple vessel perforations have evolved many times independently of species having scalariform perforations, but detailed studies to understand why these transitions in wood evolution have happened are lacking. We focus on the striking difference in wood anatomy between two closely related genera of Adoxaceae, Viburnum and Sambucus, and link the anatomical divergence with climatic and physiological insights. Methods After performing wood anatomical observations, we used a molecular phylogenetic framework to estimate divergence times for 127 Adoxaceae species. The conditions under which the genera diversified were estimated using ancestral area reconstruction and optimization of ancestral climates, and xylem-specific conductivity measurements were performed. Key Results Viburnum, characterized by scalariform vessel perforations (ancestral), diversified earlier than Sambucus, having simple perforations (derived). Ancestral climate reconstruction analyses point to cold temperate preference for Viburnum and warm temperate for Sambucus. This is reflected in the xylem-specific conductivity rates of the co-occurring species investigated, showing that Viburnum lantana has rates much lower than Sambucus nigra. Conclusions The lack of selective pressure for high conductive efficiency during early diversification of Viburnum and the potentially adaptive value of scalariform perforations in frost-prone cold temperate climates have led to retention of the ancestral vessel perforation type, while higher temperatures during early diversification of Sambucus have triggered the evolution of simple vessel perforations, allowing more efficient long-distance water transport. PMID:27498812

Surgical management of perforated duodenal ulcer: the changing scene.

PubMed

Plummer, J M; McFarlane, M E C; Newnham

2004-12-01

To determine the management of perforated duodenal ulcer at the University Hospital of the West Indies (UHWI) in this era of Helicobacter pylori, the medical records of all patients seen at the UHWI during the period July 1997 to June 2002 with an intra-operative diagnosis of perforated peptic ulcer were reviewed The records were analyzed for the following: age, gender, duration of symptoms, non-steroidal anti-inflammatory drug (NSAID) use, smoking status, operative repair duration of hospitalization, Helicobacter pylori status and medical therapy, peri-operative complications, mortality and recurrence. Ninety per cent of the cases were males. All females in whom perforation occurred were age 50 years and older compared to males where 58% of cases presented before age 50 years. Perforations in acute ulcers occurred in 80% of cases. The majority of patients were male smokers. Non-steroidal anti-inflammatory drug use was also an important risk factor in elderly females. Simple surgical closure and standard triple therapy antibiotics to eradicate Helicobacter pylori was the most common treatment offered. Mortality was one per cent and follow-up poor but 11% of patients had documented recurrent peptic ulceration. In this study population, perforated duodenal ulcer occured overwhelmingly in males less than 50 years of age. There is a trend towards exclusive simple surgical closure and H pylori eradication at the UHWI for patients with perforated duodenal ulcer but this needs to be supported by documentation of H pylori prevalence in the population of patients presenting with perforated peptic ulcers.

Analysis of risk factors for postoperative morbidity in perforated peptic ulcer.

PubMed

Kim, Jae-Myung; Jeong, Sang-Ho; Lee, Young-Joon; Park, Soon-Tae; Choi, Sang-Kyung; Hong, Soon-Chan; Jung, Eun-Jung; Ju, Young-Tae; Jeong, Chi-Young; Ha, Woo-Song

2012-03-01

Emergency operations for perforated peptic ulcer are associated with a high incidence of postoperative complications. While several studies have investigated the impact of perioperative risk factors and underlying diseases on the postoperative morbidity after abdominal surgery, only a few have analyzed their role in perforated peptic ulcer disease. The purpose of this study was to determine any possible associations between postoperative morbidity and comorbid disease or perioperative risk factors in perforated peptic ulcer. In total, 142 consecutive patients, who underwent surgery for perforated peptic ulcer, at a single institution, between January 2005 and October 2010 were included in this study. The clinical data concerning the patient characteristics, operative methods, and complications were collected retrospectively. The postoperative morbidity rate associated with perforated peptic ulcer operations was 36.6% (52/142). Univariate analysis revealed that a long operating time, the open surgical method, age (≥60), sex (female), high American Society of Anesthesiologists (ASA) score and presence of preoperative shock were significant perioperative risk factors for postoperative morbidity. Significant comorbid risk factors included hypertension, diabetes mellitus and pulmonary disease. Multivariate analysis revealed a long operating time, the open surgical method, high ASA score and the presence of preoperative shock were all independent risk factors for the postoperative morbidity in perforated peptic ulcer. A high ASA score, preoperative shock, open surgery and long operating time of more than 150 minutes are high risk factors for morbidity. However, there is no association between postoperative morbidity and comorbid disease in patients with a perforated peptic ulcer.

Towards real-time VMAT verification using a prototype, high-speed CMOS active pixel sensor.

PubMed

Zin, Hafiz M; Harris, Emma J; Osmond, John P F; Allinson, Nigel M; Evans, Philip M

2013-05-21

This work investigates the feasibility of using a prototype complementary metal oxide semiconductor active pixel sensor (CMOS APS) for real-time verification of volumetric modulated arc therapy (VMAT) treatment. The prototype CMOS APS used region of interest read out on the chip to allow fast imaging of up to 403.6 frames per second (f/s). The sensor was made larger (5.4 cm × 5.4 cm) using recent advances in photolithographic technique but retains fast imaging speed with the sensor's regional read out. There is a paradigm shift in radiotherapy treatment verification with the advent of advanced treatment techniques such as VMAT. This work has demonstrated that the APS can track multi leaf collimator (MLC) leaves moving at 18 mm s(-1) with an automatic edge tracking algorithm at accuracy better than 1.0 mm even at the fastest imaging speed. Evaluation of the measured fluence distribution for an example VMAT delivery sampled at 50.4 f/s was shown to agree well with the planned fluence distribution, with an average gamma pass rate of 96% at 3%/3 mm. The MLC leaves motion and linac pulse rate variation delivered throughout the VMAT treatment can also be measured. The results demonstrate the potential of CMOS APS technology as a real-time radiotherapy dosimeter for delivery of complex treatments such as VMAT.

A Compact Operational Amplifier with Load-Insensitive Stability Compensation for High-Precision Transducer Interface.

PubMed

Yu, Zhanghao; Yang, Xi; Chung, SungWon

2018-01-29

High-resolution electronic interface circuits for transducers with nonlinear capacitive impedance need an operational amplifier, which is stable for a wide range of load capacitance. Such operational amplifier in a conventional design requires a large area for compensation capacitors, increasing costs and limiting applications. In order to address this problem, we present a gain-boosted two-stage operational amplifier, whose frequency response compensation capacitor size is insensitive to the load capacitance and also orders of magnitude smaller compared to the conventional Miller-compensation capacitor that often dominates chip area. By exploiting pole-zero cancellation between a gain-boosting stage and the main amplifier stage, the compensation capacitor of the proposed operational amplifier becomes less dependent of load capacitance, so that it can also operate with a wide range of load capacitance. A prototype operational amplifier designed in 0.13-μm complementary metal-oxide-semiconductor (CMOS) with a 400-fF compensation capacitor occupies 900- μ m 2 chip area and achieves 0.022-2.78-MHz unity gain bandwidth and over 65 ∘ phase margin with a load capacitance of 0.1-15 nF. The prototype amplifier consumes 7.6 μ W from a single 1.0-V supply. For a given compensation capacitor size and a chip area, the prototype design demonstrates the best reported performance trade-off on unity gain bandwidth, maximum stable load capacitance, and power consumption.

Initial steps toward the realization of large area arrays of single photon counting pixels based on polycrystalline silicon TFTs

NASA Astrophysics Data System (ADS)

Liang, Albert K.; Koniczek, Martin; Antonuk, Larry E.; El-Mohri, Youcef; Zhao, Qihua; Jiang, Hao; Street, Robert A.; Lu, Jeng Ping

2014-03-01

The thin-film semiconductor processing methods that enabled creation of inexpensive liquid crystal displays based on amorphous silicon transistors for cell phones and televisions, as well as desktop, laptop and mobile computers, also facilitated the development of devices that have become ubiquitous in medical x-ray imaging environments. These devices, called active matrix flat-panel imagers (AMFPIs), measure the integrated signal generated by incident X rays and offer detection areas as large as ~43×43 cm2. In recent years, there has been growing interest in medical x-ray imagers that record information from X ray photons on an individual basis. However, such photon counting devices have generally been based on crystalline silicon, a material not inherently suited to the cost-effective manufacture of monolithic devices of a size comparable to that of AMFPIs. Motivated by these considerations, we have developed an initial set of small area prototype arrays using thin-film processing methods and polycrystalline silicon transistors. These prototypes were developed in the spirit of exploring the possibility of creating large area arrays offering single photon counting capabilities and, to our knowledge, are the first photon counting arrays fabricated using thin film techniques. In this paper, the architecture of the prototype pixels is presented and considerations that influenced the design of the pixel circuits, including amplifier noise, TFT performance variations, and minimum feature size, are discussed.

Design of power electronics for TVC EMA systems

NASA Technical Reports Server (NTRS)

Nelms, R. Mark

1993-01-01

The Composite Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. This report presents the results of an investigation into the applicability of two new technologies, MOS-controlled thyristors (MCT's) and pulse density modulation (PDM), to the control of brushless dc motors in EMA systems. MCT's are new power semiconductor devices, which combine the high voltage and current capabilities of conventional thyristors and the low gate drive requirements of metal oxide semiconductor field effect transistors (MOSFET's). The commanded signals in a PDM system are synthesized using a series of sinusoidal pulses instead of a series of square pulses as in a pulse width modulation (PWM) system. A resonant dc link inverter is employed to generate the sinusoidal pulses in the PDM system. This inverter permits zero-voltage switching of all semiconductors which reduces switching losses and switching stresses. The objectives of this project are to develop and validate an analytical model of the MCT device when used in high power motor control applications and to design, fabricate, and test a prototype electronic circuit employing both MCT and PDM technology for controlling a brushless dc motor.

Mass sensing AlN sensors for waste water monitoring

NASA Astrophysics Data System (ADS)

Porrazzo, R.; Potter, G.; Lydecker, L.; Foraida, Z.; Gattu, S.; Tokranova, N.; Castracane, J.

2014-08-01

Monitoring the presence of nanomaterials in waste water from semiconductor facilities is a critical task for public health organizations. Advanced semiconductor technology allows the fabrication of sensitive piezoelectric-based mass sensors with a detection limit of less than 1.35 ng/cm2 of nanomaterials such as nanoparticles of alumina, amorphous silica, ceria, etc. The interactions between acoustic waves generated by the piezoelectric sensor and nanomaterial mass attached to its surface define the sensing response as a shift in the resonant frequency. In this article the development and characterization of a prototype AlN film bulk acoustic resonator (FBAR) are presented. DC reactive magnetron sputtering was used to create tilted c-axis oriented AlN films to generate shear waves which don't propagate in liquids thus minimizing the acoustic losses. The high acoustic velocity of AlN over quartz allows an increase in resonance frequency in comparison with a quartz crystal microbalance (QCM) and results in a higher frequency shift per mass change, and thus greater sensitivity. The membrane and electrodes were fabricated using state of the art semiconductor technology. The device surface functionalization was performed to demonstrate selectivity towards a specific nanomaterial. As a result, the devices were covered with a "docking" layer that allows the nanomaterials to be selectively attached to the surface. This was achieved using covalent modification of the surface, specifically targeting ZnO nanoparticles. Our functionalization approach was tested using two different types of nanoparticles, and binding specificity was confirmed with various analytical techniques.

Photovoltaic and photoelectrochemical conversion of solar energy.

PubMed

Grätzel, Michael

2007-04-15

The Sun provides approximately 100,000 terawatts to the Earth which is about 10000 times more than the present rate of the world's present energy consumption. Photovoltaic cells are being increasingly used to tap into this huge resource and will play a key role in future sustainable energy systems. So far, solid-state junction devices, usually made of silicon, crystalline or amorphous, and profiting from the experience and material availability resulting from the semiconductor industry, have dominated photovoltaic solar energy converters. These systems have by now attained a mature state serving a rapidly growing market, expected to rise to 300 GW by 2030. However, the cost of photovoltaic electricity production is still too high to be competitive with nuclear or fossil energy. Thin film photovoltaic cells made of CuInSe or CdTe are being increasingly employed along with amorphous silicon. The recently discovered cells based on mesoscopic inorganic or organic semiconductors commonly referred to as 'bulk' junctions due to their three-dimensional structure are very attractive alternatives which offer the prospect of very low cost fabrication. The prototype of this family of devices is the dye-sensitized solar cell (DSC), which accomplishes the optical absorption and the charge separation processes by the association of a sensitizer as light-absorbing material with a wide band gap semiconductor of mesoporous or nanocrystalline morphology. Research is booming also in the area of third generation photovoltaic cells where multi-junction devices and a recent breakthrough concerning multiple carrier generation in quantum dot absorbers offer promising perspectives.

[Spontaneous perforation of the hepatic duct during biliary lithiasis complicated by acute pancreatitis].

PubMed

Assadourian, R; Chometowski, S; Bourde, J; Poitout, D; Lamy, J

1975-10-01

The association of perforation of the common bile duct, cholecystitis and acute pancreatitis, should be emphasized. Physiopathology of perforation of the bile duct may be compared with that of pancreatitis. Repair of the bile duct may be delicate requiring hepatico-jejunostomy on an isolated loop.

Pre-expanded Intercostal Perforator Super-Thin Skin Flap.

PubMed

Liao, Yunjun; Luo, Yong; Lu, Feng; Hyakusoku, Hiko; Gao, Jianhua; Jiang, Ping

2017-01-01

This article introduces pre-expanded super-thin intercostal perforator flaps, particularly the flap that has a perforator from the first to second intercostal spaces. The key techniques, advantages and disadvantages, and complications and management of this flap are described. At present, the thinnest possible flap is achieved by thinning the pre-expanded flap that has a perforator from the first to second intercostal spaces. It is used to reconstruct large defects on the face and neck, thus restoring function and cosmetic appearance. Copyright © 2016 Elsevier Inc. All rights reserved.

Invading of intrauterine contraceptive device into the sigmoid colon through uterine perforation caused by a blunt trauma.

PubMed

Davoodabadi, Abdoulhossein; Mohammadzadeh, Mahdi; Amirbeigi, Mahdieh; Jazayeri, Hoda

2015-01-01

Intrauterine contraceptive device (IUCD) is relatively safe but still with some serious risks. Uterus perforation is rare and would be fatal. A case of Cu-7 IUCD invading into the sigmoid colon through uterine perforation caused by a pelvic blunt trauma was presented. Our case showed that uterus perforation by an IUCD could induce utero-sigmoid fistula which is likely to be missed. Imaging is required when the patients with IUCD present abdominal pain, particularly with a history of trauma.

Stercoral perforation of the colon proximal to an end colostomy.

PubMed Central

Serpell, J. W.; Sen, M.; Giddins, G.; Nicholls, R. J.; Bradfield, W. J.

1991-01-01

Stercoral perforation of the colon is rare, and has not previously been reported as a postoperative complication, proximal to an end colostomy. Two such cases are reported; in addition in one the stercoral perforation was recurrent, emphasizing the multifocal nature of the disease. Both cases demonstrate the failure of standard techniques to deal with scybala in the loaded proximal colon. It is, therefore, suggested that intra-operative orthograde colonic lavage is indicated to protect a terminal colostomy from the risk of stercoral perforation in such cases. PMID:2062783

Pneumatosis cystoides intestinalis associated with massive free air mimicking perforated diffuse peritonitis.

PubMed

Sakurai, Yoichi; Hikichi, Masahiro; Isogaki, Jun; Furuta, Shinpei; Sunagawa, Risaburo; Inaba, Kazuki; Komori, Yoshiyuki; Uyama, Ichiro

2008-11-21

While pneumatosis cystoides intestinalis (PCI) is a rare disease entity associated with a wide variety of gastrointestinal and non-gastrointestinal disorders, PCI associated with massive intra- and retroperitoneal free air is extremely uncommon, and is difficult to diagnose differentially from perforated peritonitis. We present two cases of PCI associated with massive peritoneal free air and/or retroperitoneal air that mimicked perforated peritonitis. These cases highlight the clinical importance of PCI that mimics perforated peritonitis, which requires emergency surgery. Preoperative imaging modalities and diagnostic laparoscopy are useful to make an accurate diagnosis.

Perforated duodenal ulcer -a rare cause of acute abdomen in pregnancy.

PubMed

Goel, Bharti; Rani, Jyotsna; Huria, Anju; Gupta, Pratiksha; Dalal, Usha

2014-09-01

Acute abdomen during pregnancy is a medico-surgical emergency demanding concerted, synchronized specialties approach of obstetrician, surgeon and gastroenterologist. Duodenal perforation is one of the rarer causes of acute abdomen in pregnancy. Here, we report a case of duodenal perforation with peritonitis in third trimester of pregnancy requiring surgical management. Our aim of reporting this case is to stress the physicians to keep the differential of duodenal perforation also in mind while dealing with cases of acute abdomen in pregnancy and to proceed with multidisciplinary approach for better feto-maternal outcome.

[Surgical tactics at "difficult" perforative duodenal ulcers].

PubMed

Kolosovych, I V; Bezrodnyĭ, B H; Chemodanov, P V; Sysak, O M

2013-09-01

Bacteriological research of abdominal cavities exsudate is conducted to 264 patients on perforative duodenal ulcers and the dynamics of peritonitis motion is studied in a postoperative period. It is set that already hour-long after the perforation of duodenal ulcer, according to information of peritoneal maintenance pH-metry and it's bacteriologic research, the optimum conditions for progress of inflammatory and infectious factors are created in an abdominal cavity. Therefore a formal term from the moment of perforation can not be the index of degree of inflammation (bacterial contamination) of peritoneum. The methods of duodenoplasty are improved at the giant perforative ulcers of duodenum and ulcers, combined with tubular stenosis of duodenum, allowed to avoid development of purulent-septic postoperative complications through insolvency of stitches and severe motor function disturbances.

Augmented reality and dynamic infrared thermography for perforator mapping in the anterolateral thigh

PubMed Central

Cifuentes, Ignacio Javier; Dagnino, Bruno Leonardo; Salisbury, María Carolina; Perez, María Eliana; Ortega, Claudia; Maldonado, Daniela

2018-01-01

Dynamic infrared thermography (DIRT) has been used for the preoperative mapping of cutaneous perforators. This technique has shown a positive correlation with intraoperative findings. Our aim was to evaluate the accuracy of perforator mapping with DIRT and augmented reality using a portable projector. For this purpose, three volunteers had both of their anterolateral thighs assessed for the presence and location of cutaneous perforators using DIRT. The obtained image of these “hotspots” was projected back onto the thigh and the presence of Doppler signals within a 10-cm diameter from the midpoint between the lateral patella and the anterior superior iliac spine was assessed using a handheld Doppler device. Hotspots were identified in all six anterolateral thighs and were successfully projected onto the skin. The median number of perforators identified within the area of interest was 5 (range, 3–8) and the median time needed to identify them was 3.5 minutes (range, 3.3–4.0 minutes). Every hotspot was correlated to a Doppler sound signal. In conclusion, augmented reality can be a reliable method for transferring the location of perforators identified by DIRT onto the thigh, facilitating its assessment and yielding a reliable map of potential perforators for flap raising. PMID:29788686

Suitability of hair type for dermatophytes perforation and differential diagnosis of T. mentagrophytes from T. verrucosum.

PubMed

Al-Janabi, Ali Abdul Hussein S; Ai-Tememi, Nabaa N; Ai-Shammari, Rabab A; Ai-Assadi, Abdul Hadi A

2016-04-01

Most of the dermatophyte species have the ability to perforate hair structure and consume its contents of keratin through secretion of keratinase enzyme. Two clinical isolated species of dermatophytes were diagnosed as Trichophyton mentagrophytes var. granulosum and Trichophyton verrucosum. To determine the perforation ability, the isolated fungi were incubated with the hair of four different animals (rabbit, rat, cow and cat) and human hairs with three different colours (black, albino and bleached yellow) for different periods. Variable perforating ability of T. mentagrophytes was shown in rat hair and all types of human hair after 15 days, while other mammalian hairs exhibited resistance to this fungal activity. On the other hand, T. verrucosum was revealed a slow perforating ability, which needed a long time (60 days) for most of tested hairs. Perforation of human black hair could be considered a diagnostic test for differentiation between T. mentagrophytes and T. verrucosum. In conclusion, the treated or untreated human hair was considered more suitable to use as a source of keratin for the growth of dermatophytes than animal hairs. The human black hair was a best type of hair to use in the perforating test for differentiation between T. mentagrophytes and T. verrucosum. © 2016 Blackwell Verlag GmbH.

Behavior of poly(glycerol sebacate) plugs in chronic tympanic membrane perforations.

PubMed

Sundback, C A; McFadden, J; Hart, A; Kulig, K M; Wieland, A M; Pereira, M J N; Pomerantseva, I; Hartnick, C J; Masiakos, P T

2012-10-01

The tympanic membrane (TM), separating the external and middle ear, consists of fibrous connective tissue sandwiched between epithelial layers. To treat chronic ear infections, tympanostomy drainage tubes are placed in surgically created holes in TMs which can become chronic perforations upon extrusion. Perforations are repaired using a variety of techniques, but are limited by morbidity, unsatisfactory closure rates, or minimal regeneration of the connective tissue. A more effective, minimally-invasive therapy is necessary to enhance the perforation closure rate. Current research utilizing decellularized or alignate materials moderately enhance closure but the native TM architecture is not restored. Poly(glycerol sebacate) (PGS) is a biocompatible elastomer which supports cell migration and enzymatically degrades in contact with vascularized tissue. PGS spool-shaped plugs were manufactured using a novel process. Using minimally invasive procedures, these elastomeric plugs were inserted into chronic chinchilla TM perforations. As previously reported, effective perforation closure occurred as both flange surfaces were covered by confluent cell layers; >90% of perforations were closed at 6-week postimplantation. This unique in vivo environment has little vascularized tissue. Consequently, PGS degradation was minimal over 16-week implantation, hindering regeneration of the TM fibrous connective tissue. PGS degradation must be enhanced to promote complete TM regeneration. Copyright © 2012 Wiley Periodicals, Inc.

The Lumbar Artery Perforator Flap: 3-Dimensional Anatomical Study and Clinical Applications.

PubMed

Bissell, Mary Beth; Greenspun, David T; Levine, Josh; Rahal, William; Al-Dhamin, Ammar; AlKhawaji, Ali; Morris, Steven F

2016-10-01

The lumbar region is a potential donor site for perforator-based rotational or free flaps or as a recipient site for free flaps to obtain coverage for deficits in the sacral region. Because of the lack of consensus regarding the microvascular anatomy of this potential flap site, a robust investigation of the anatomy of this region is required. Three-dimensional reconstructions (n = 6) of the microvasculature of the lumbar region were generated using MIMICS software (Materialise, Belgium) for each of the four paired lumbar vessels. Diameter, course, and pedicle length were recorded for all lumbar artery (LA) perforators. Statistical analysis was performed using SigmaStat 4.0 and graphs were generated using GraphPad Prism 6 Software. Perforators arising from the first pair of LAs are reliably detected along the inferior margin of the 12th rib, extending inferiorly and laterally from the midline while perforators arising from the fourth pair of LA perforate the fascia along a horizontal plane connecting the posterior iliac crests. There are significantly more cutaneous perforators arising from the first (L1) and fourth (L4) pairs of LA than from the second (L2) and third (L3) (mean ± SD: L1, 5.5 ± 1.2; L2, 1.4 ± 0.7; L3, 1.3 ± 0.7; L4, 4.8 ± 1.0; P < 0.05). The average perforator diameter arising from L1 is greater than those arising from L4 (diameter ± SD: L1, 1.2 mm ± 0.2 >L4, 0.8 mm ± 0.2; P < 0.0001). L1 and L4 perforators have longer pedicle lengths than those arising from L2 and L3 (length ± SD: L1, 98.2 mm ± 57.8; L4, 106.1 mm ± 23.3 >L2, 67.5 mm ± 27.4; L3, 78.5 mm ± 30.3; P < 0.05). Perforators arising from the first and fourth LAs arise in a predictable fashion, have adequate pedicle lengths, and are of suitable diameter to support a perforator flap. We present a case to support the potential use of this flap for microvascular breast reconstruction.

Novel sensor for color control in solid state lighting applications

NASA Astrophysics Data System (ADS)

Gourevitch, Alex; Thurston, Thomas; Singh, Rajiv; Banachowicz, Bartosz; Korobov, Vladimir; Drowley, Cliff

2010-02-01

LED wavelength and luminosity shifts due to temperature, dimming, aging, and binning uncertainty can cause large color errors in open-loop light-mixing illuminators. Multispectral color light sensors combined with feedback circuits can compensate for these LED shifts. Typical color light sensor design variables include the choice of light-sensing material, filter configuration, and read-out circuitry. Cypress Semiconductor has designed and prototyped a color sensor chip that consists of photodiode arrays connected to a I/F (Current to Frequency) converter. This architecture has been chosen to achieve high dynamic range (~100dB) and provide flexibility for tailoring sensor response. Several different optical filter configurations were evaluated in this prototype. The color-sensor chip was incorporated into an RGB light color mixing system with closed-loop optical feedback. Color mixing accuracy was determined by calculating the difference between (u',v') set point values and CIE coordinates measured with a reference colorimeter. A typical color precision ▵u'v' less than 0.0055 has been demonstrated over a wide range of colors, a temperature range of 50C, and light dimming up to 80%.

Proximal Corporal Perforation During Penile Prosthesis Surgery: Prevention, Recognition, and Review of Historical and Novel Management Strategies.

PubMed

Pearlman, Amy M; Terlecki, Ryan P

2018-05-02

Proximal corporal perforation at time of dilation, although rare, may occur due to factors related to patient anatomy, presence of intra-cavernosal fibrosis, and/or surgical technique. To describe tools and techniques designed to prevent and identify proximal corporal perforation, and maneuvers to minimize the risk of subsequent cylinder migration once proximal perforation has been recognized, such that the operation may proceed and result in an acceptable outcome. We discuss tips for prevention, recognition, and management of proximal corporal perforation by presenting a review of the literature as well as our preferences based on a high-volume experience with penile prosthesis surgery. Described techniques aim to minimize risk of cylinder migration in the absence of true proximal repair. Although proximal perforation may be obvious at times, particularly with a sudden loss of resistance during dilation, discrepant corporal measurements and/or dissimilar proximal deflection of the dilator should also increase the index of suspicion. Numerous techniques have been employed to theoretically reduce the risk of cylinder migration in the setting of proximal corporal perforation. These include formal corporal repair (historical), windsock repairs with non-absorbable grafts, absorbable plugs, and suture fixation of the rear tip extender or shod material covering implant tubing. Intra-operative recognition of proximal corporal perforation, coupled with understanding of surgical strategies to minimize the risk of future device migration, may allow completion of an operation that still results in an optimal outcome. Techniques described to prevent proximal migration are not strongly evidence-based, but rooted in logic and supported by high-volume implanters. Intra-operative perforation of the proximal corpora, although rare, can threaten the success of penile implant surgery, though the techniques described herein have been developed to mitigate the potential for subsequent device migration, allowing surgery to proceed and to achieve the desired clinical result. Pearlman AM, Terlecki RP. Proximal Corporal Perforation During Penile Prosthesis Surgery: Prevention, Recognition, and Review of Historical and Novel Management Strategies. J Sex Med 2018;XX:XXX-XXX. Copyright © 2018 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Calf Perforator Flaps: A Freestyle Solution for Oral Cavity Reconstruction.

PubMed

Molina, Alexandra R; Citron, Isabelle; Chinaka, Fungayi; Cascarini, Luke; Townley, William A

2017-02-01

Reconstruction of oral cavity defects requires a thin, pliable flap for optimal functional results. Traditional flap choices are imperfect: the anterolateral thigh flap is excessively thick, whereas the radial forearm flap has a poor donor site. The authors therefore favor calf perforator flaps such as the medial sural artery perforator flap to provide thin tissue with an acceptable donor site. This two-part study aims to demonstrate their suitability for intraoral reconstruction. In the radiologic part of the study, the authors compared thigh and calf tissue thickness by examining lower limb computed tomographic scans of 100 legs. For their clinical study, they collected data prospectively on 20 cases of oral cavity reconstruction using calf perforator flaps. The mean thickness of the calf tissue envelope was significantly less than that of the thigh (8.4 mm compared with 17 mm) based on computed tomographic analysis. In the clinical study, a medial sural artery perforator was used in the majority of cases (17 of 20). The mean pedicle length was 10.2 cm and the mean time to raise a flap was 85 minutes. There were no flap losses. One patient was returned to the operating room for management of late hematoma and wound dehiscence. Calf perforator flaps provide ideal tissue for intraoral reconstruction and are significantly thinner than anterolateral thigh flaps. In addition to medial sural artery perforator flaps, the authors raised both sural and soleal artery perforator flaps in this series. Opportunistic use of the calf donor site allows the harvest of thin tissue with minimal donor-site morbidity. Therapeutic, IV.

Mucosal Perforation During Laparoscopic Heller Myotomy Has No Influence on Final Treatment Outcome.

PubMed

Salvador, Renato; Spadotto, Lorenzo; Capovilla, Giovanni; Voltarel, Guerrino; Pesenti, Elisa; Longo, Cristina; Cavallin, Francesco; Nicoletti, Loredana; Ruol, Alberto; Valmasoni, Michele; Merigliano, Stefano; Costantini, Mario

2016-12-01

The aims of the study were (a) to examine the final outcome in patients experiencing accidental mucosal perforation during laparoscopic Heller myotomy with Dor fundoplication (LHD) and (b) to evaluate whether perforation episodes might influence the way in which surgeons subsequently approached the LHD procedure. We studied all consecutive patients that underwent LHD between 1992 and 2015. Patients were divided into two main groups: those who experienced an intraoperative mucosal perforation (group P) and those whose LHD was uneventful (group NP). Two additional groups were compared: group A, which consisted of patients operated by a given surgeon immediately before a perforation episode occurred, and group B, which included those operated immediately afterwards. Eight hundred seventy-five patients underwent LHD; a mucosal perforation was detected in 25 patients (2.9 %), which was found unrelated to patients' symptom's score and age, radiological stage, manometric pattern, or the surgeon's experience. The median postoperative symptom score was similar for the two groups as the failure rate: 92 failures in group NP (10.8 %) and 4 in group P (16 %) (p = 0.34); moreover, symptoms recurred in 2 patients of group A (10 %) and 3 patients of group B (15 %) (p = 0.9). Accidental perforation during LHD is infrequent and impossible to predict on the grounds of preoperative therapy or the surgeon's personal experience. Despite a longer surgical procedure and hospital stay, the outcome of LHD is much the same as for patients undergoing uneventful myotomy. A recent mucosal perforation does not influence the surgeon's subsequent performance.

The anatomical (angiosome) and clinical territories of cutaneous perforating arteries: development of the concept and designing safe flaps.

PubMed

Taylor, G Ian; Corlett, Russell J; Dhar, Shymal C; Ashton, Mark W

2011-04-01

Island "perforator flaps" have become state of the art for free-skin flap transfer. Recent articles by Saint-Cyr et al. and Rozen et al. have focused on the anatomical and the clinical territories of individual cutaneous perforating arteries in flap planning, and it is timely to compare this work with our angiosome concept. The angiosome concept, published in 1987, was reviewed and correlated with key experimental and clinical work by the authors, published subsequently at different times in different journals. In addition, new data are introduced to define these anatomical and clinical territories of the cutaneous perforators and to aid in the planning of safe skin flaps for local and free-flap transfer. The anatomical territory of a cutaneous perforator was defined in the pig, dog, guinea pig, and rabbit by a line drawn through its perimeter of anastomotic vessels that link it with adjacent perforators in all directions. The safe clinical territory of that perforator, seen not only in the same range of animals but also in the human using either the Doppler probe or computed tomography angiography to locate the vessels, was found reliably to extend to include the anatomical territory of the next adjacent cutaneous perforator, situated radially in any direction. The data provided by Saint-Cyr et al. and Rozen et al., coupled with the authors' own original work on the vascular territories of the body and their subsequent studies, reinforce the angiosome concept and provide the basis for the design of safe flaps for patient benefit.

Video Capture of Perforator Flap Harvesting Procedure with a Full High-definition Wearable Camera

PubMed Central

2016-01-01

Summary: Recent advances in wearable recording technology have enabled high-quality video recording of several surgical procedures from the surgeon’s perspective. However, the available wearable cameras are not optimal for recording the harvesting of perforator flaps because they are too heavy and cannot be attached to the surgical loupe. The Ecous is a small high-resolution camera that was specially developed for recording loupe magnification surgery. This study investigated the use of the Ecous for recording perforator flap harvesting procedures. The Ecous SC MiCron is a high-resolution camera that can be mounted directly on the surgical loupe. The camera is light (30 g) and measures only 28 × 32 × 60 mm. We recorded 23 perforator flap harvesting procedures with the Ecous connected to a laptop through a USB cable. The elevated flaps included 9 deep inferior epigastric artery perforator flaps, 7 thoracodorsal artery perforator flaps, 4 anterolateral thigh flaps, and 3 superficial inferior epigastric artery flaps. All procedures were recorded with no equipment failure. The Ecous recorded the technical details of the perforator dissection at a high-resolution level. The surgeon did not feel any extra stress or interference when wearing the Ecous. The Ecous is an ideal camera for recording perforator flap harvesting procedures. It fits onto the surgical loupe perfectly without creating additional stress on the surgeon. High-quality video from the surgeon’s perspective makes accurate documentation of the procedures possible, thereby enhancing surgical education and allowing critical self-reflection. PMID:27482504

Peritonitis secondary to spontaneous perforation of a primary gastrointestinal stromal tumour of the small intestine: A case report and a literature review.

PubMed

Alessiani, Mario; Gianola, Marco; Rossi, Sabina; Perfetti, Vittorio; Serra, Piero; Zelaschi, Daniela; Magnani, Enzo; Cobianchi, Lorenzo

2015-01-01

A few cases of acute abdomen caused by perforation of small-intestinal gastrointestinal stromal tumours (GISTs) have been reported in the literature. Together with a review of the published cases, here we report a case of an elderly patient with peritonitis due to spontaneous perforation of a GIST of the jejunum. An 82-year-old man was admitted to the emergency unit of our hospital with fever and severe abdominal pain. An abdominal enhanced computed tomography scan detected a 6cm solid mass in the left upper quadrant adherent to a jejunal loop and surrounded by free fluid and free air. Due to the radiological features of the mass, the diagnosis of a perforation of a GIST arising from the jejunum wall was suspected. The patient underwent emergency laparotomy. Intraoperative findings confirmed diffuse peritonitis secondary to jejunal tumour perforation. A segmental resection of the jejunum containing the mass was performed followed by a mechanical end-to-side anastomosis. The histopathologic examination of the mass confirmed the diagnosis of a perforated GIST of the small intestine (high-risk category). The post-operative course was uneventful and the patient was treated with adjuvant imatinib therapy. Twenty-one other cases of spontaneous perforation of small intestine GISTs are reported in the literature and are summarized in the present review. The described case is the tip of the iceberg and spontaneous rupture or perforation of GISTs are a far more frequent first presentation of this rare tumour. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Factors related to persisting perforations after ventilation tube insertion.

PubMed

O'Connell Ferster, Ashley P; Tanner, April Michelle; Karikari, Kodjo; Roberts, Christopher; Wiltz, Derek; Carr, Michele M

2016-02-01

Over a million ventilation tubes are placed annually in the United States, making this one of the most commonly performed procedures in the field of medicine. Certain factors increase the risk of persistent tympanic membrane perforation following the extrusion of short term ventilation tubes. Persistent perforations may fail to heal on their own, necessitating surgical closure to avoid conductive hearing loss. It is important to detect factors that may predict children who are at increased risk for persistent perforations. This study was a retrospective chart review that involved 757 patients between 2003 and 2008. The patients studied were within the age of 2 months-17 years, and all had short term tubes placed. The chart data also included demographic information, comorbidities, and information related to tube insertion and follow-up care. Chi-square, t-test, and multivariate logistic regression were conducted to compare variables between patients with perforations and those without. Data from 757 patients was analyzed, showing that perforation rate is associated with rhinorrhea, operative tube removal, aural polyps, and otorrhea (OR 1.72, 8.16, 4.69, and 1.72 respectively). The absence of otorrhea decreased the likelihood of TM perforations and no significant differences were found in gender, total number of sets of tubes, type of tube, use of nasal steroids, adenoidectomy, or nasal congestion. Our findings suggest that children with rhinorrhea, otorrhea, aural polyps, or prolonged intubation requiring operative tube removal should be identified clinically as children at risk of persisting perforation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Surgical therapies for corneal perforations: 10 years of cases in a tertiary referral hospital

PubMed Central

Yokogawa, Hideaki; Kobayashi, Akira; Yamazaki, Natsuko; Masaki, Toshinori; Sugiyama, Kazuhisa

2014-01-01

Purpose To report surgical therapies for corneal perforations in a tertiary referral hospital. Methods Thirty-one eyes of 31 patients (aged 62.4±18.3 years) with surgically treated corneal perforations from January 2002 to July 2013 were included in this study. Demographic data such as cause of corneal perforation, surgical procedures, and visual outcomes were retrospectively analyzed. Results The causes of corneal perforation (n=31) were divided into infectious (n=8, 26%) and noninfectious (n=23, 74%) categories. Infectious causes included fungal ulcer, herpetic stromal necrotizing keratitis, and bacterial ulcer. The causes of noninfectious keratopathy included corneal melting after removal of a metal foreign body, severe dry eye, lagophthalmos, canaliculitis, the oral anticancer drug S-1, keratoconus, rheumatoid arthritis, neurotrophic ulcer, atopic keratoconjunctivitis, and unknown causes. Initial surgical procedures included central large corneal graft (n=17), small corneal graft (n=7), and amniotic membrane transplantation (n=7). In two cases the perforation could not be sealed during the first surgical treatment and required subsequent procedures. All infectious keratitis required central large penetrating keratoplasty to obtain anatomical cure. In contrast, several surgical options were used for the treatment of noninfectious keratitis. After surgical treatment, anatomical cure was obtained in all cases. Mean postoperative best corrected visual acuity was better at 6 months (logMAR 1.3) than preoperatively (logMAR 1.8). Conclusion Surgical therapies for corneal perforations in our hospital included central large lamellar/penetrating keratoplasty, small peripheral patch graft, and amniotic membrane transplantation. All treatments were effective. Corneal perforation due to the oral anticancer drug S-1 is newly reported. PMID:25378903

Costs of treating bleeding and perforated peptic ulcers in The Netherlands.

PubMed

de Leest, Helena; van Dieten, Hiske; van Tulder, Maurits; Lems, Willem F; Dijkmans, Ben A C; Boers, Maarten

2004-04-01

Gastrointestinal toxicity of nonsteroidal antiinflammatory drugs includes perforations and bleeds. Several preventive strategies are being tested for cost-effectiveness, but little is known about the costs of the complications they are trying to prevent. We estimated the direct costs of hospital treatment of bleeding and perforated ulcers in a university hospital, from data in discharge letters and the hospital management information system. Eligible patients had been treated in the VU University Medical Center between January 1997 and August 2000 for an ulcer bleed or perforation (International Classification of Diseases code 531-4). Resource use comprised hospitalization days and diagnostic and therapeutic interventions. Insurance claim prices determined the costs from the payers' perspective. In a secondary analysis we excluded resource use that was clearly related to the treatment of comorbid illness. Fifty-three patients with a bleeding (n = 35) or perforated ulcer (n = 15) or both (n = 3) were studied, including 14 with comorbidity; 22 complications occurred in the stomach, 29 in the duodenum, one in both stomach and duodenum, and one after partial gastrectomy. A simultaneous bleed and perforation was most expensive (26,000 euro), followed by perforation (19,000 euro) and bleeding (12,000 euro). A bleed in the duodenum was more expensive than in the stomach (13,000 euro vs 10,000 euro), while the opposite was seen for perforations (13,000 euro vs 21,000 euro). Comorbidity increased costs substantially: even after correction for procedures unrelated to the ulcer complication, comorbidity more than doubled the costs of treatment. Treatment of complicated ulcers is expensive, especially in patients with comorbid conditions.

Analysis of Risk Factors for Postoperative Morbidity in Perforated Peptic Ulcer

PubMed Central

Kim, Jae-Myung; Jeong, Sang-Ho; Park, Soon-Tae; Choi, Sang-Kyung; Hong, Soon-Chan; Jung, Eun-Jung; Ju, Young-Tae; Jeong, Chi-Young; Ha, Woo-Song

2012-01-01

Purpose Emergency operations for perforated peptic ulcer are associated with a high incidence of postoperative complications. While several studies have investigated the impact of perioperative risk factors and underlying diseases on the postoperative morbidity after abdominal surgery, only a few have analyzed their role in perforated peptic ulcer disease. The purpose of this study was to determine any possible associations between postoperative morbidity and comorbid disease or perioperative risk factors in perforated peptic ulcer. Materials and Methods In total, 142 consecutive patients, who underwent surgery for perforated peptic ulcer, at a single institution, between January 2005 and October 2010 were included in this study. The clinical data concerning the patient characteristics, operative methods, and complications were collected retrospectively. Results The postoperative morbidity rate associated with perforated peptic ulcer operations was 36.6% (52/142). Univariate analysis revealed that a long operating time, the open surgical method, age (≥60), sex (female), high American Society of Anesthesiologists (ASA) score and presence of preoperative shock were significant perioperative risk factors for postoperative morbidity. Significant comorbid risk factors included hypertension, diabetes mellitus and pulmonary disease. Multivariate analysis revealed a long operating time, the open surgical method, high ASA score and the presence of preoperative shock were all independent risk factors for the postoperative morbidity in perforated peptic ulcer. Conclusions A high ASA score, preoperative shock, open surgery and long operating time of more than 150 minutes are high risk factors for morbidity. However, there is no association between postoperative morbidity and comorbid disease in patients with a perforated peptic ulcer. PMID:22500261

Simple patch closure for perforated peptic ulcer in children followed by helicobacter pylori eradication.

PubMed

Yildiz, Turan; Ilce, Huri Tilla; Ceran, Canan; Ilce, Zekeriya

2014-05-01

Peptic ulcer disease in children is rare. Therefore, the diagnosis can be missed until complications such as perforation or hemorrhage occur. Few reports have investigated the procedures and outcomes of children who have undergone operations for perforated duodenal ulcers. We report our experience with the modified Graham technique for perforated duodenal ulcers in nine children and review the literature. Methods : The records of patients operated on for a perforated duodenal ulcer in the last 8 years in two pediatric surgery centers were evaluated retrospectively. Patient demographics, symptoms, time to admission to hospital, operative findings, and postoperative clinical course were evaluated. Results : Nine children (mean age 13.2 years, range 6-170 years) were included. All patients were admitted in the first six hours after their abdominal pain started. In three patients, there was free air on plain x-rays, while the x-rays were normal in six. All perforations were located on the anterior surface of the first part of the duodenum and repaired with primary suturing and Graham patch omentoplasty. The recovery was uneventful in all patients. In five patients, urea breath tests were performed postoperatively for Helicobacter Pylori, and the results were positive. All patients underwent triple therapy with lansoprazole, amoxicillin, and clarithromycin. The mean follow-up time was 58 (range 3-94) months. Conclusions : Peptic ulcer perforation should be suspected in children who have acute abdominal pain and peritoneal signs, especially when their suffering is intense. The simple patch repair and postoperative triple therapy for Helicobacter Pylori are safe and satisfactory for treating peptic ulcer perforation in children.

7 CFR 52.1845 - Sizes of seedless raisins.

Code of Federal Regulations, 2013 CFR

2013-01-01

... percent, by weight, of all the raisins will pass through round perforations 22/64-inch in diameter, but not more than 10 percent, by weight, of all the raisins may pass through round perforations 20/64-inch... will pass through round perforations 24/64-inch in diameter, and not less than 70 percent, by weight...

7 CFR 52.1845 - Sizes of seedless raisins.

Code of Federal Regulations, 2014 CFR

2014-01-01

... percent, by weight, of all the raisins will pass through round perforations 22/64-inch in diameter, but not more than 10 percent, by weight, of all the raisins may pass through round perforations 20/64-inch... will pass through round perforations 24/64-inch in diameter, and not less than 70 percent, by weight...

Laparoscopic repair of perforated peptic ulcer-technical tip.

PubMed

Jayanthi, Naga Venkatesh Gupta

2013-08-01

Increasing number of gastrointestinal emergencies are managed laparoscopically. Laparoscopic repair of a perforated peptic ulcer remains contentious. Fashioning an omental patch is a crucial and an essential part of this repair, whether it is performed open or laparoscopically. This article describes a technique to fashion an adequate omental patch over the perforated peptic ulcer.

Effects of nasal septum perforation repair surgery on three-dimensional airflow: an evaluation using computational fluid dynamics.

PubMed

Nomura, Tsutomu; Ushio, Munetaka; Kondo, Kenji; Yamasoba, Tatsuya

2015-11-01

The purpose of this research is to determine the cause of nasal perforation symptoms and to predict post-operative function after nasal perforation repair surgery. A realistic three-dimensional (3D) model of the nose with a septal perforation was reconstructed using a computed tomography (CT) scan from a patient with nasal septal defect. The numerical simulation was carried out using ANSYS CFX V13.0. Pre- and post-operative models were compared by their velocity, pressure gradient (PG), wall shear (WS), shear strain rate (SSR) and turbulence kinetic energy in three plains. In the post-operative state, the crossflows had disappeared, and stream lines bound to the olfactory cleft area had appeared. After surgery, almost all of high-shear stress areas were disappeared comparing pre-operative model. In conclusion, the effects of surgery to correct nasal septal perforation were evaluated using a three-dimensional airflow evaluation. Following the surgery, crossflows disappeared, and WS, PG and SSR rate were decreased. A high WS.PG and SSR were suspected as causes of nasal perforation symptoms.

Perforation and bacterial contamination of microscope covers in lumbar spinal decompressive surgery.

PubMed

Osterhoff, Georg; Spirig, José; Klasen, Jürgen; Kuster, Stefan P; Zinkernagel, Annelies S; Sax, Hugo; Min, Kan

2014-01-01

To determine the integrity of microscope covers and bacterial contamination at the end of lumbar spinal decompressive surgery. A prospective study of 25 consecutive lumbar spinal decompressions with the use of a surgical microscope was performed. For detection of perforations, the microscope covers were filled with water at the end of surgery and the presence of water leakage in 3 zones (objective, ocular and control panel) was examined. For detection of bacterial contamination, swabs were taken from the covers at the same locations before and after surgery. Among the 25 covers, 1 (4%) perforation was observed and no association between perforation and bacterial contamination was seen; 3 (4%) of 75 smears from the 25 covers showed post-operative bacterial contamination, i.e. 2 in the ocular zone and 1 in the optical zone, without a cover perforation. The incidence of microscope cover perforation was very low and was not shown to be associated with bacterial contamination. External sources of bacterial contamination seem to outweigh the problem of contamination due to failure of cover integrity. © 2014 S. Karger AG, Basel.

Reconstruction of lower face defect or deformity with submental artery perforator flaps.

PubMed

Shi, Cheng-li; Wang, Xian-cheng

2012-07-01

Reconstruction of lower face defects or deformity often presents as a challenge for plastic surgeons. Many methods, including skin graft, tissue expander, or free flap are introduced. Submental artery perforator flaps have been used in the reconstruction of defects or deformities of the lower face. Between August 2006 and December 2008, 22 patients with lower face defects or deformity underwent reconstruction with pedicled submental artery perforator flaps. Their age ranged between 14 and 36 years. The perforator arteries were detected and labeled with a hand-held Doppler flowmeter. The size of flaps ranged from 4 × 6 to 6 × 7 cm, and the designed flaps included the perforator artery. All the flaps survived well, except 1 flap which resulted in partial necrosis in distal region and healed after conservative therapy. No other complication occurred with satisfactory aesthetic appearance of the donor site. The submental artery perforator flap is a thin and reliable flap with robust blood supply. This flap can reduce donor-site morbidity significantly and is a good choice for reconstructive surgery of lower face.

Perforated Meckel's diverticulitis complicating active Crohn's ileitis: a case report.

PubMed

Schwenter, Frank; Gervaz, Pascal; de Saussure, Philippe; McKee, Thomas; Morel, Philippe

2009-01-13

In Crohn's disease, the extension of active terminal ileitis into a Meckel's diverticulum is possible, but usually has no impact on clinical decision-making. We describe an original surgical approach in a young woman presenting with a combination of perforated Meckel's diverticulitis and active Crohn's ileitis. We report the case of a 22-year-old woman with Crohn's disease, who was admitted for abdominal pain, fever and diarrhoea. CT scan demonstrated active inflammation of the terminal ileum, as well as a fluid collection in the right iliac fossa, suggesting intestinal perforation. Laparoscopy was performed and revealed, in addition to extensive ileitis, a 3 x 3 cm abscess in connection with perforated Meckel's diverticulitis. It was therefore possible to avoid ileocaecal resection by only performing Meckel's diverticulectomy; pathological examination of the surgical specimen revealed the presence of transmural inflammation with granulomas and perforation of the diverticulum at its extremity. Crohn's disease of the ileum may be responsible for Meckel's diverticulitis and cause perforation which, in this case, proved to be a blessing in disguise and spared the patient an extensive small bowel resection.

Perforated Meckel's diverticulitis complicating active Crohn's ileitis: a case report

PubMed Central

2009-01-01

Introduction In Crohn's disease, the extension of active terminal ileitis into a Meckel's diverticulum is possible, but usually has no impact on clinical decision-making. We describe an original surgical approach in a young woman presenting with a combination of perforated Meckel's diverticulitis and active Crohn's ileitis. Case presentation We report the case of a 22-year-old woman with Crohn's disease, who was admitted for abdominal pain, fever and diarrhoea. CT scan demonstrated active inflammation of the terminal ileum, as well as a fluid collection in the right iliac fossa, suggesting intestinal perforation. Laparoscopy was performed and revealed, in addition to extensive ileitis, a 3 × 3 cm abscess in connection with perforated Meckel's diverticulitis. It was therefore possible to avoid ileocaecal resection by only performing Meckel's diverticulectomy; pathological examination of the surgical specimen revealed the presence of transmural inflammation with granulomas and perforation of the diverticulum at its extremity. Conclusion Crohn's disease of the ileum may be responsible for Meckel's diverticulitis and cause perforation which, in this case, proved to be a blessing in disguise and spared the patient an extensive small bowel resection. PMID:19144118

Finite element modeling of sound transmission with perforations of tympanic membrane

PubMed Central

Gan, Rong Z.; Cheng, Tao; Dai, Chenkai; Yang, Fan; Wood, Mark W.

2009-01-01

A three-dimensional finite element (FE) model of human ear with structures of the external ear canal, middle ear, and cochlea has been developed recently. In this paper, the FE model was used to predict the effect of tympanic membrane (TM) perforations on sound transmission through the middle ear. Two perforations were made in the posterior-inferior quadrant and inferior site of the TM in the model with areas of 1.33 and 0.82 mm2, respectively. These perforations were also created in human temporal bones with the same size and location. The vibrations of the TM (umbo) and stapes footplate were calculated from the model and measured from the temporal bones using laser Doppler vibrometers. The sound pressure in the middle ear cavity was derived from the model and measured from the bones. The results demonstrate that the TM perforations can be simulated in the FE model with geometrical visualization. The FE model provides reasonable predictions on effects of perforation size and location on middle ear transfer function. The middle ear structure-function relationship can be revealed with multi-field coupled FE analysis. PMID:19603881

Experimental and Theoretical Analysis of Sound Absorption Properties of Finely Perforated Wooden Panels.

PubMed

Song, Boqi; Peng, Limin; Fu, Feng; Liu, Meihong; Zhang, Houjiang

2016-11-22

Perforated wooden panels are typically utilized as a resonant sound absorbing material in indoor noise control. In this paper, the absorption properties of wooden panels perforated with tiny holes of 1-3 mm diameter were studied both experimentally and theoretically. The Maa-MPP (micro perforated panels) model and the Maa-Flex model were applied to predict the absorption regularities of finely perforated wooden panels. A relative impedance comparison and full-factorial experiments were carried out to verify the feasibility of the theoretical models. The results showed that the Maa-Flex model obtained good agreement with measured results. Control experiments and measurements of dynamic mechanical properties were carried out to investigate the influence of the wood characteristics. In this study, absorption properties were enhanced by sound-induced vibration. The relationship between the dynamic mechanical properties and the panel mass-spring vibration absorption was revealed. While the absorption effects of wood porous structure were not found, they were demonstrated theoretically by using acoustic wave propagation in a simplified circular pipe with a suddenly changed cross-section model. This work provides experimental and theoretical guidance for perforation parameter design.

Perforation and Bacterial Contamination of Microscope Covers in Lumbar Spinal Decompressive Surgery

PubMed Central

Osterhoff, Georg; Spirig, José; Klasen, Jürgen; Kuster, Stefan P.; Zinkernagel, Annelies S.; Sax, Hugo; Min, Kan

2014-01-01

Objective To determine the integrity of microscope covers and bacterial contamination at the end of lumbar spinal decompressive surgery. Materials and Methods A prospective study of 25 consecutive lumbar spinal decompressions with the use of a surgical microscope was performed. For detection of perforations, the microscope covers were filled with water at the end of surgery and the presence of water leakage in 3 zones (objective, ocular and control panel) was examined. For detection of bacterial contamination, swabs were taken from the covers at the same locations before and after surgery. Results Among the 25 covers, 1 (4%) perforation was observed and no association between perforation and bacterial contamination was seen; 3 (4%) of 75 smears from the 25 covers showed post-operative bacterial contamination, i.e. 2 in the ocular zone and 1 in the optical zone, without a cover perforation. Conclusions The incidence of microscope cover perforation was very low and was not shown to be associated with bacterial contamination. External sources of bacterial contamination seem to outweigh the problem of contamination due to failure of cover integrity. PMID:24903448

Management of nontraumatic corneal perforation with tectonic drape patch and cyanoacrylate glue.

PubMed

Khalifa, Yousuf M; Bailony, M Rami; Bloomer, Michele M; Killingsworth, Daniel; Jeng, Bennie H

2010-10-01

To report a case of nontraumatic corneal perforation managed with a tectonic drape patch. Interventional case report. A 60-year-old patient with a corneal scar in his left eye likely secondary to herpes simplex virus interstitial keratitis underwent laser peripheral iridotomy for narrow angles. He developed progressive thinning of the cornea overlying the scar that led to a descemetocele and then ultimately a 1.2- × 1.7-mm perforation. Intraoperatively, several attempts were made to seal the perforation with cyanoacrylate glue, but the wound continued to leak. Sterile plastic drape that was on the surgical field was fashioned into a 2-mm-diameter patch, and the peripheral edge of the tectonic drape patch was glued over the perforation, successfully sealing the cornea. One week later, the drape patch was intact without leak, and a penetrating keratoplasty was carried out without complication. Tectonic drape patch technique for nontraumatic corneal perforations in which there is tissue loss is a viable temporizing option when cyanoacrylate glue alone fails and when there is no corneal tissue or amniotic membrane available to close the wound.

Endoscopic duodenal perforation: surgical strategies in a regional centre

PubMed Central

2014-01-01

Background Duodenal perforation is an uncommon complication of endoscopic retrograde cholangio-pancreatography (ERCP) and a rare complication of upper gastrointestinal endoscopy. Most are minor perforations that settle with conservative management. A few perforations however result in life-threatening retroperitoneal necrosis and require surgical intervention. There is a relative paucity of references specifically describing the surgical interventions required for this eventuality. Methods Five cases of iatrogenic duodenal perforation were ascertained between 2002 and 2007 at Cairns Base Hospital. Clinical features were analyzed and compared, with reference to a review of ERCP at that institution for the years 2005/2006. Results One patient recovered with conservative management. Of the other four, one died after initial laparotomy. The other three survived, undergoing multiple procedures and long inpatient stays. Conclusions Iatrogenic duodenal perforation with retroperitoneal necrosis is an uncommon complication of endoscopy, but when it does occur it is potentially life-threatening. Early recognition may lead to a better outcome through earlier intervention, although a protracted course with multiple procedures should be anticipated. A number of surgical techniques may need to be employed according to the individual circumstances of the case. PMID:24461069

Trans-anal barotrauma by compressed air leading to sigmoid perforation due to a dangerous practical joke

PubMed Central

Pahwa, Harvinder Singh; Kumar, Awanish; Srivastava, Rohit; Rai, Anurag

2012-01-01

To present a case report of trans-anal barotrauma by high-pressure compressed air jet as a dangerous practical joke, that is, playful insufflation of high-pressure air jet through the anal orifice resulting in sigmoid perforation. The patient presented to emergency a day later with complaints of severe pain in the abdomen and abdominal distension following insufflation of high-pressure air jet through the anus. On examination, he had signs suggestive of perforation peritonitis and x-ray of the abdomen showed gas under the diaphragm. An emergency exploratory laparotomy was performed which revealed a 4-cm perforation in the sigmoid colon. Resection of the segment containing perforation along with the surrounding devitalised part was done with double-barrel colostomy. Reversal of colostomy was done after 8 weeks. Follow-up was uneventful. PMID:22854240

Trans-anal barotrauma by compressed air leading to sigmoid perforation due to a dangerous practical joke.

PubMed

Pahwa, Harvinder Singh; Kumar, Awanish; Srivastava, Rohit; Rai, Anurag

2012-08-01

To present a case report of trans-anal barotrauma by high-pressure compressed air jet as a dangerous practical joke, that is, playful insufflation of high-pressure air jet through the anal orifice resulting in sigmoid perforation. The patient presented to emergency a day later with complaints of severe pain in the abdomen and abdominal distension following insufflation of high-pressure air jet through the anus. On examination, he had signs suggestive of perforation peritonitis and x-ray of the abdomen showed gas under the diaphragm. An emergency exploratory laparotomy was performed which revealed a 4-cm perforation in the sigmoid colon. Resection of the segment containing perforation along with the surrounding devitalised part was done with double-barrel colostomy. Reversal of colostomy was done after 8 weeks. Follow-up was uneventful.

Nasal septum perforation of welders.

PubMed

Lee, Choong Ryeol; Yoo, Cheol In; Lee, Ji ho; Kang, Seong Kyu

2002-07-01

During the periodic physical checkups in 1997-2000, the authors have found eleven cases of nasal septum perforation among 2,869 welders in Ulsan, Korea. They have not suffered from diseases and conditions that could cause septum perforation such as tuberculosis, syphilis, and long-term use of topical corticosteroids. And also they did not have trauma history and surgical experiences on their nasal septum. To investigate the cause of septum perforation we reviewed the past history of pre-employment, the results of annual working environment survey and the material safety data sheets of welding rods and steels with which they have dealt. We also analyzed the concentration of several metals of welding fume and the concentration of blood and urinary chromium. In the result, we assumed that the nasal septum perforation of welders was due to chronic exposure to low-level hexavalent chromium.

New devices and techniques for endoscopic closure of gastrointestinal perforations

PubMed Central

Li, Yue; Wu, Jian-Hua; Meng, Yan; Zhang, Qiang; Gong, Wei; Liu, Si-De

2016-01-01

Gastrointestinal perforations, which need to be managed quickly, are associated with high morbidity and mortality. Treatments used to close these perforations range from surgery to endoscopic therapy. Nowadays, with the development of new devices and techniques, endoscopic therapy is becoming more popular. However, there are different indications and clinical efficacies between different methods, because of the diverse properties of endoscopic devices and techniques. Successful management also depends on other factors, such as the precise location of the perforation, its size and the length of time between the occurrence and diagnosis. In this study, we performed a comprehensive review of various devices and introduced the different techniques that are considered effective to treat gastrointestinal perforations. In addition, we focused on the different methods used to achieve successful closure, based on the literature and our clinical experiences. PMID:27672268

A case of perforating injury of eyeball and traumatic cataract caused by acupuncture.

PubMed

Shuang, Han; Yichun, Kong

2016-04-01

Perforating globe injury is the leading cause of monocular blindness and vision loss. A 58-year-old male was injured by acupuncture needle during acupuncture treatment for his cerebral infarction. To the best of our knowledge, this is the first case report of perforating injury of the eyeball and traumatic cataract caused by acupuncture. The patient was hospitalized due to diagnosis of perforating ocular injury, traumatic cataract, and corneal and iris perforating injury. Moreover, he had to accept treatments of phacoemulsification, anterior vitrectomy along with intraocular lens implantation in the sulcus to improve his visual acuity. As acupuncture therapy has been widely performed for various diseases and achieved highly approval, the aim of this report is to remind acupuncturists operating accurately to avoid unnecessary injury during the treatment process, or the cure can also become the weapon.

Fouling resilient perforated feed spacers for membrane filtration.

PubMed

Kerdi, Sarah; Qamar, Adnan; Vrouwenvelder, Johannes S; Ghaffour, Noreddine

2018-04-24

The improvement of feed spacers with optimal geometry remains a key challenge for spiral-wound membrane systems in water treatment due to their impact on the hydrodynamic performance and fouling development. In this work, novel spacer designs are proposed by intrinsically modifying cylindrical filaments through perforations. Three symmetric perforated spacers (1-Hole, 2-Hole, and 3-Hole) were in-house 3D-printed and experimentally evaluated in terms of permeate flux, feed channel pressure drop and membrane fouling. Spacer performance is characterized and compared with standard no perforated (0-Hole) design under constant feed pressure and constant feed flow rate. Perforations in the spacer filaments resulted in significantly lowering the net pressure drop across the spacer filled channel. The 3-Hole spacer was found to have the lowest pressure drop (50%-61%) compared to 0-Hole spacer for various average flow velocities. Regarding permeate flux production, the 0-Hole spacer produced 5.7 L m -2 .h -1 and 6.6 L m -2 .h -1 steady state flux for constant pressure and constant feed flow rate, respectively. The 1-Hole spacer was found to be the most efficient among the perforated spacers with 75% and 23% increase in permeate production at constant pressure and constant feed flow, respectively. Furthermore, membrane surface of 1-Hole spacer was found to be cleanest in terms of fouling, contributing to maintain higher permeate flux production. Hydrodynamic understanding of these perforated spacers is also quantified by performing Direct Numerical Simulation (DNS). The performance enhancement of these perforated spacers is attributed to the formation of micro-jets in the spacer cell that aided in producing enough unsteadiness/turbulence to clean the membrane surface and mitigate fouling phenomena. In the case of 1-Hole spacer, the unsteadiness intensity at the outlet of micro-jets and the shear stress fluctuations created inside the cells are higher than those observed with other perforated spacers, resulting in the cleanest membrane surface. Copyright © 2018 Elsevier Ltd. All rights reserved.

Early appendectomy shortens antibiotic course and hospital stay in children with early perforated appendicitis.

PubMed

Tsai, Hsin-Yu; Chao, Hsun-Chin; Yu, Wan-Ju

2017-10-01

The optimal management of perforated appendicitis in the pediatric population has been controversial. This study aimed to compare the therapeutic efficacy between conservative treatment (CS) and early appendectomy (EA) in pediatric perforated appendicitis, and to determine whether surgical intervention is an optimal treatment modality for early perforated appendicitis in children. Patients treated between January 2012 and April 2014, aged 0-18 years, with an imaging-based diagnosis of perforated appendicitis were retrospectively reviewed. Patients were classified into nonabscess and abscess groups by image findings, and were further categorized into CS and EA groups by treatment modality. Early perforated appendicitis was defined as having duration of symptoms≤7 days, C-reactive protein level≤200 mg/L, maximum abscess diameter≤5 cm, and absence of general peritonitis, and unstable vital signs. The clinical features and therapeutic outcomes were compared between CS and EA in each group. A total of 326 patients had confirmed appendicitis, including 116 patients with an image diagnosis of perforation. The CS group had a significantly longer duration of symptoms, larger abscesses, and higher serum C-reactive protein levels at presentation (all p<0.05). Patients in the EA group had a shorter antibiotic course and length of hospitalization, and a lower rate of antibiotic escalation than those in the CS group (p<0.001, p<0.001, and p<0.05, respectively). In patients with early perforated appendicitis, the CS and EA groups showed no difference in baseline disease severity. Patients in the EA group also had a shorter antibiotic course and length of hospitalization than those in the CS group (p<0.001 and p<0.001, respectively). Compared with CS, EA shortens the antibiotic course and hospital stay in pediatric early perforated appendicitis, even in the presence of small abscesses. Copyright © 2017. Published by Elsevier B.V.

Neurodevelopmental Outcomes of Extremely Low Birth Weight Infants with Spontaneous Intestinal Perforation or Surgical Necrotizing Enterocolitis

PubMed Central

Wadhawan, Rajan; Oh, William; Hintz, Susan R; Blakely, Martin L; Das, Abhik; Bell, Edward F.; Saha, Shampa; Laptook, Abbot R.; Shankaran, Seetha; Stoll, Barbara J.; Walsh, Michele C.; Higgins, Rosemary D.

2013-01-01

Objective To determine if extremely low birth weight infants with surgical necrotizing enterocolitis have a higher risk of death or neurodevelopmental impairment and neurodevelopmental impairment among survivors (secondary outcome) at 18–22 months corrected age compared to infants with spontaneous intestinal perforation and infants without necrotizing enterocolitis or spontaneous intestinal perforation. Study Design Retrospective analysis of the Neonatal Research Network very low birth weight registry, evaluating extremely low birth weight infants born between 2000–2005. The study infants were designated into 3 groups: 1) Spontaneous intestinal perforation without necrotizing enterocolitis; 2) Surgical necrotizing enterocolitis (Bell's stage III); and 3) Neither spontaneous intestinal perforation nor necrotizing enterocolitis. Multivariate logistic regression analysis was performed to evaluate the association between the clinical group and death or neurodevelopmental impairment, controlling for multiple confounding factors including center. Results Infants with surgical necrotizing enterocolitis had the highest rate of death prior to hospital discharge (53.5%) and death or neurodevelopmental impairment (82.3%) compared to infants in the spontaneous intestinal perforation group (39.1% and 79.3%) and no necrotizing enterocolitis/no spontaneous intestinal perforation group (22.1% and 53.3%; p<0.001). Similar results were observed for neurodevelopmental impairment among survivors. On logistic regression analysis, both spontaneous intestinal perforation and surgical necrotizing enterocolitis were associated with increased risk of death or neurodevelopmental impairment (adjusted OR 2.21, 95% CI: 1.5, 3.2 and adjusted OR 2.11, 95% CI: 1.5, 2.9 respectively) and neurodevelopmental impairment among survivors (adjusted OR 2.17, 95% CI: 1.4, 3.2 and adjusted OR 1.70, 95% CI: 1.2, 2.4 respectively). Conclusions Spontaneous intestinal perforation and surgical necrotizing enterocolitis are associated with a similar increase in the risk of death or neurodevelopmental impairment and neurodevelopmental impairment among extremely low birth weight survivors at 18–22 months corrected age. PMID:24135709

Pathophysiological Factors Associated with Left Ventricular Perforation in Transcatheter Aortic Valve Implantation by Transfemoral Approach.

PubMed

Owais, Tamer; El Garhy, Mohammad; Fuchs, Jürgen; Disha, Kushtrim; Elkaffas, Sameh; Breuer, Martin; Lauer, Bernward; Kuntze, Thomas

2017-07-01

Left ventricular (LV) perforation is one of the rare and most serious complications of transcatheter aortic valve implantation (TAVI). The study aim was to determine the pathophysiological factors associated with this serious complication. A retrospective study was conducted of pathophysiological factors shown in echocardiograms and computed tomography angiograms performed preoperatively in patients who developed LV perforation during transfemoral TAVI (study group) with regards to anatomic and functional variables. Results were then compared with data acquired from a randomly selected sample of patients without perforation (control group). Among 963 TAVI cases, LV perforation occurred in 11 patients (three males, eight females; mean age 79 years). These patients showed complications of LV perforation that required emergency sternotomy and repair of injury to the left ventricle. Ten patients were rescued by the procedure, but one patient died during surgery. Focus on preoperative factors and intraoperative steps was established in favor to identify possible predictors of LV perforation. A LV cavity size <4.2 cm and a hypercontractile ventricle were identified in 10 patients (90%). Only one patient had a dilated cardiomyopathic left ventricle, with a cavity size of 6.1 cm and an ejection fraction of 10%. The present study results revealed other specific patient-related factors, namely a narrow aorto-mitral angle and a thin ventricular muscular wall despite long-standing aortic stenosis. All 11 patients had an average mid-LV muscular wall thickness of 5 mm. An inverse proportional relationship between the aorto-mitral angle and the incidence of perforation was noted, where in all 11 patients the wire had directed itself towards the anterior free wall of the left ventricle, where it induced injury. A small LV cavity, a hypercontractile state, a thin muscular wall, and a narrow aorto-mitral angle may be considered potential predictors of the occurrence of LV perforation during TAVI.

The Supraclavicular Artery Perforator Flap: A Comparative Study of Imaging Techniques Used in Preoperative Mapping.

PubMed

Sheriff, Hemin Oathman; Mahmood, Kawa Abdullah; Hamawandi, Nzar; Mirza, Aram Jamal; Hawas, Jawad; Moreno, Esther Granell; Clavero, Juan Antonio; Hankins, Christopher; Masia, Jaume

2018-05-18

 The supraclavicular artery flap is an excellent flap for head and neck reconstruction. The aim of this study is to assess imaging techniques to define the precise vascular boundaries of this flap.  Six imaging techniques were used for supraclavicular artery mapping in 65 cases; handheld Doppler, triplex ultrasound, computed tomography angiography, magnetic resonance angiography, digital subtraction angiography, and indocyanine green angiography. We checked the site of the perforators, the course of a supraclavicular artery, and anatomical mapping of the supraclavicular artery.  Handheld Doppler identified perforators' sites in 80% of the cases but showed no results for the course of the vessel. Triplex ultrasound identified the site of perforators in 52.9%, and partial mapping of the course of a supraclavicular artery in 64.7% of the cases. Computerized tomography angiography showed the site of perforators in 60%, and the course of supraclavicular artery completely in 45%, and partially in an additional 30%of the cases examined. Magnetic resonance angiography showed negative results for all parameters. Digital subtraction angiography showed the partial course of a supraclavicular artery in 62.5%, but showed no perforators. Indocyanine green angiography showed the site of perforators in 60% and a partial course of supraclavicular artery distal to perforators in 60%.Anatomical mapping of the vessel was possible with computerized tomography angiogram completely in 45%, and partially in 30%, and was also possible with indocyanine green angiography partially in 60%.  Computerized tomography angiography showed best results in the mapping of the supraclavicular artery, but with an inability to define the perforator perfusion territories, and also with risks of irradiation, while indocyanine green angiography is a good alternative as it could precisely map the superficial course of the artery and angiosomes, with no radiation exposure. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Long-term observation of endodontic surgical intervention to treat root perforation and apical periodontitis: a case report of an amalgam-restored tooth.

PubMed

Tsurumachi, Tamotsu; Hayashi, Makoto

2003-10-01

A case of crestal root perforation and periapical lesion in a maxillary left lateral incisor is reported. Teeth with root perforation present technical difficulties in their clinical management because of their complex defects. In the present case, surgical endodontic treatment was chosen. The apical and lateral pathology was curetted, the tooth root was resected, and a retrograde root restoration of amalgam was placed in a root-end cavity and perforation site. A 10-year follow-up clinical and radiographic examination showed an asymptomatic tooth with osseous healing proceeding.

Osteonecrosis related to intraosseous anesthesia: report of a case.

PubMed

Woodmansey, Karl F; White, Robert K; He, Jianing

2009-02-01

Intraosseous anesthesia is an effective and increasingly used technique with few reported complications. The technique uses a specialized drill to perforate the osseous cortex where local anesthetic can then be deposited to anesthetize teeth. It has been reported that separation of the perforation drills from their plastic bases can occur because of the friction generated during osseous perforation. Prolonged rotation of the perforator drills in the bone can also cause excessive heat, which can lead to bone necrosis. This report describes a case of focal osteonecrosis subsequent to intraosseous anesthesia and discusses possible etiologies of this sequela.

Role of over the scope clips in the management of iatrogenic gastrointestinal perforations

PubMed Central

Changela, Kinesh; Virk, Muhhamad A; Patel, Niravkumar; Duddempudi, Sushil; Krishnaiah, Mahesh; Anand, Sury

2014-01-01

Advances in endoscopic and surgical techniques have increased the frequency and complexity of these procedures and associated complications such as gastrointestinal perforation. With the advancements in the field of gastroenterology, the promising use of an over the scope clips (OTSC) has fulfilled the unmet need for a reliable endoscopic devise in approximation of gastrointestinal perforation. This novel approach has raised the level of confidence in endoscopist in dealing with this serious complication during endoscopy. Here we have shared our experience with OTSC to evaluate its efficacy and safety in managing iatrogenic gastrointestinal perforations during endoscopy. PMID:25170237

Localized intestinal perforations as a potential complication of brain hypothermic therapy for perinatal asphyxia.

PubMed

Nishizaki, Naoto; Maiguma, Atsuko; Obinata, Kaoru; Okazaki, Tadaharu; Shimizu, Toshiaki

2016-01-01

Brain hypothermic therapy (BHT) is becoming a frequently used standard of care for perinatal asphyxia. Although cardiovascular side effects, coagulation disorders, renal impairment, electrolyte abnormalities, impaired liver function, opportunistic infections, and skin lesions are well-known adverse effects of BHT in newborns, little information is available on the clinical features of intestinal perforation-related BHT. We herein report a case of therapeutic brain cooling for perinatal asphyxia complicated by localized intestinal perforation. In practice, the neonatologist should be aware that intestinal perforation in an infant with perinatal asphyxia is possible, particularly following BHT.

Role of over the scope clips in the management of iatrogenic gastrointestinal perforations.

PubMed

Changela, Kinesh; Virk, Muhhamad A; Patel, Niravkumar; Duddempudi, Sushil; Krishnaiah, Mahesh; Anand, Sury

2014-08-28

Advances in endoscopic and surgical techniques have increased the frequency and complexity of these procedures and associated complications such as gastrointestinal perforation. With the advancements in the field of gastroenterology, the promising use of an over the scope clips (OTSC) has fulfilled the unmet need for a reliable endoscopic devise in approximation of gastrointestinal perforation. This novel approach has raised the level of confidence in endoscopist in dealing with this serious complication during endoscopy. Here we have shared our experience with OTSC to evaluate its efficacy and safety in managing iatrogenic gastrointestinal perforations during endoscopy.

A rare case of duodenal ulcer perforation accompanied by Boerhaave syndrome

PubMed Central

Rokicki, Wojciech; Rokicki, Marek

2015-01-01

Esophageal perforation is the fastest progressing and the most life-threatening disruption of gastrointestinal tract continuity. It must be regarded as an emergency condition that requires early diagnosis as well as very aggressive and rapid implementation of treatment in order to avoid serious complications and death. Methods of treatment for spontaneous esophageal perforation continue to be a matter of controversy. However, all authors emphasize that ultimate success depends largely on the time taken to establish the diagnosis. The authors of this study describe a rare case of duodenal ulcer perforation accompanied by Boerhaave syndrome. PMID:26702287

[Development of a perforated peptic ulcer in a child during high dose prednisolone treatment].

PubMed

Moll Harboe, Kirstine; Midtgaard, Helle; Wewer, Vibeke; Cortes, Dina

2012-09-24

Since perforated peptic ulcer is uncommon in children proton pump inhibitor prophylaxis is not routinely recommended when children are treated with high dose steroids. We describe a case of perforated ulcer in a six-year-old patient with nephrotic syndrome treated with high dose prednisolone. Initially, ulcer was not suspected due to uncharacteristic symptoms. The child developed peritoneal signs and surgery revealed a perforated peptic ulcer in the stomach. We recommend treatment with proton pump inhibitors if children, who are treated with high dose steroids develop abdominal symptoms, which can be caused by an ulcus.

Impact of nasal septal perforations of varying sizes and locations on the warming function of the nasal cavity: A computational fluid-dynamics analysis of 5 cases.

PubMed

Li, Lifeng; Han, Demin; Zhang, Luo; Li, Yunchuan; Zang, Hongrui; Wang, Tong; Liu, Yingxi

2016-09-01

Patients with a nasal septal perforation often exhibit symptoms associated with disturbed airflow, which can have an adverse effect on the warming function of the nasal cavity. The impact of this effect is not fully understood. The warming function is an important factor in the maintenance of nasal physiology. We conducted a study to investigate the impact of septal perforations of various sizes and locations on the warming function during inspiration in 5 patients-3 men and 2 women, aged 25 to 47 years. Three-dimensional computed tomography and computational fluid dynamics were used to model the flux of communication and temperature, and differences among patients were compared. All 5 patients exhibited an impairment of their nasal warming function. As the size of the perforation increased, the flux of communication increased and the warming function decreased. Perforations located in an anterior position were associated with greater damage to the warming function than those in a posterior position. In patients with a large or anteriorly located perforation, airflow temperature in the nasopharynx was decreased. Our findings suggest that septal perforations not only induce airflow disturbance, but they also impair the nasal warming function. Further analysis of warming function is necessary to better explore flow mechanisms in patients with structural abnormalities.

Validation of Boey's score in predicting morbidity and mortality in peptic perforation peritonitis in Northwestern India.

PubMed

Agarwal, Abhishek; Jain, Sanchit; Meena, L N; Jain, Sumita A; Agarwal, Lakshman

2015-01-01

The major complications of peptic ulcer are hemorrhage, perforation and gastric outlet obstruction with perforation occurring in about 2-10% of patients. Patients with perforated peptic ulcer still have a high rate of morbidity and mortality and to improve the outcomes it is important to stratify the patients into different categories. To evaluate the accuracy of Boey scoring system in predicting postoperative morbidity and mortality in patients operated for peptic perforation. It was a prospective observational single centre study conducted at SMS Medical College and Hospital, Jaipur, from October 2011 to October 2012 on 180 patients undergoing open surgery for peptic ulcer perforation. Postoperative outcomes in terms of recovery and complications were studied. For prediction of morbidity and mortality by Boey risk stratification, the odds ratio (OR) and 95% confidence interval (95% CI) of each risk score were compared with the outcomes of "0" risk score. The mortality rate increased progressively with increasing numbers of the Boey score: 1.9%, 7.1%, 31.7% and 40% for 0, 1, 2, and 3 scores, respectively (p < 0.001). The morbidity rates for 0, 1, 2, and 3 Boey scores were 13%, 45.7%, 70.7% and 73.3% respectively (p < 0.001). Boey score is a useful tool for assessing the prognosis of operated cases of peptic perforation and helps in the assessment of mortality and morbidity of these patients.

Involvement of intracellular Zn2+ signaling in LTP at perforant pathway-CA1 pyramidal cell synapse.

PubMed

Tamano, Haruna; Nishio, Ryusuke; Takeda, Atsushi

2017-07-01

Physiological significance of synaptic Zn 2+ signaling was examined at perforant pathway-CA1 pyramidal cell synapses. In vivo long-term potentiation (LTP) at perforant pathway-CA1 pyramidal cell synapses was induced using a recording electrode attached to a microdialysis probe and the recording region was locally perfused with artificial cerebrospinal fluid (ACSF) via the microdialysis probe. Perforant pathway LTP was not attenuated under perfusion with CaEDTA (10 mM), an extracellular Zn 2+ chelator, but attenuated under perfusion with ZnAF-2DA (50 μM), an intracellular Zn 2+ chelator, suggesting that intracellular Zn 2+ signaling is required for perforant pathway LTP. Even in rat brain slices bathed in CaEDTA in ACSF, intracellular Zn 2+ level, which was measured with intracellular ZnAF-2, was increased in the stratum lacunosum-moleculare where perforant pathway-CA1 pyramidal cell synapses were contained after tetanic stimulation. These results suggest that intracellular Zn 2+ signaling, which originates in internal stores/proteins, is involved in LTP at perforant pathway-CA1 pyramidal cell synapses. Because the influx of extracellular Zn 2+ , which originates in presynaptic Zn 2+ release, is involved in LTP at Schaffer collateral-CA1 pyramidal cell synapses, synapse-dependent Zn 2+ dynamics may be involved in plasticity of postsynaptic CA1 pyramidal cells. © 2017 Wiley Periodicals, Inc.

The Anterior Interosseus Artery Perforator Flap: Anatomical Dissections and Clinical Study.

PubMed

Panse, Nikhil S; Joshi, Sheetal B; Sahasrabudhe, Parag B; Bahetee, B; Gurude, Pradnya; Chandanwale, Ajay

2017-05-01

Reconstruction of upper extremity deformities continues to be a challenge to the reconstructive surgeon. Various loco regional, distant and free flaps are available for reconstruction. However, each has its own set of advantages and disadvantages. Of the commonly performed local flaps, radial artery forearm flap, and the posterior interosseus artery flap stand out prominently. Recently, perforator propeller flaps have been used for resurfacing the upper extremity. The anterior interosseus artery perforator flap is an uncommonly used and described flap. This study was divided into anatomical study and clinical application in a IV level of evidence. In the anatomical study, five upper extremities were studied. Clinically, 12 patients underwent reconstruction using the anterior interosseus artery perforator flap. Flaps were performed by a single surgeon. A retrospective review of these cases from November 2008 to May 2014 is presented. The anterior interosseus artery perforator was identified in four out of five cadaver limbs. The septocutaneous perforator was in the fifth extensor compartment around 4 cm proximal to the wrist joint. Of the twelve flaps, there was complete necrosis in one flap, and partial necrosis in one flap. The patient with complete necrosis underwent skin grafting at a later date. The wound healed secondarily in case of partial flap necrosis. Anterior interosseus artery perforator flap must be considered as an important reconstructive option in the armamentarium of the plastic surgeon, while managing hand and wrist defects.

Simultaneous non-traumatic perforation of the right hepatic duct and gallbladder: an atypical occurrence.

PubMed

Garg, Pankaj Kumar; Jain, Bhupendra Kumar; Pandey, Satya Deo; Rathi, Vinita; Puri, Amarendra Singh

2012-07-01

Simultaneous non-traumatic perforation of the extrahepatic bile duct and the gallbladder is an uncommon occurrence that has been infrequently reported. We describe a patient with a spontaneous perforation of both the extrahepatic bile duct and the gallbladder. A contrast-enhanced computed tomography (CECT) scan of the abdomen and endoscopic retrograde cholangiopancreatography (ERCP) demonstrated a perforation of the gallbladder and a free leak from the right hepatic duct, respectively. Endoscopic biliary drainage following a sphincterotomy and biliary stent placement led to a dramatic improvement in the patient's general condition. He was subsequently scheduled to undergo an elective cholecystectomy. Repeat ERCP performed at 4 weeks after the initial stenting showed a normal cholangiogram and a distally migrated stent, which was there after removed. However, early stent removal led to re-perforation of hepatic duct and gallbladder. A repeat endoscopic biliary drainage did not help, and the patient developed biliary peritonitis. Surgical exploration revealed a perforation at the fundus of the gallbladder, 400 ml of biliopurulent collection and a frozen Calot's triangle. A subtotal cholecystectomy, gall stone removal, and a thorough peritoneal lavage were undertaken. The patient improved postoperatively. The second biliary stent was removed after 4 months. This case report highlights the role of endoscopic biliary drainage in the management of an extrahepatic bile duct perforation and warns against the early removal of a biliary stent.

Colorectal cancer with intestinal perforation - a retrospective analysis of treatment outcomes.

PubMed

Banaszkiewicz, Zbigniew; Woda, Łukasz; Tojek, Krzysztof; Jarmocik, Paweł; Jawień, Arkadiusz

2014-01-01

Colorectal cancer (CRC) is one of the leading cause of death in European population. It progresses without any symptoms in the early stages or those clinical symptoms are very discrete. The aim of this study was a retrospective analysis of treatment outcomes in patients with colorectal cancer complicated with intestinal perforation. A retrospective analysis of patients urgently operated upon in our Division of General Surgery, because of large intestine perforation, from February 1993 to February 2013 has been made. Results were compared with a group of patients undergoing the elective surgery for colorectal cancer in the same time and Division. Intestinal perforation occurred more often in males (6.52% vs. 6.03%), patients with mucous component in histopathological examination (9.09% vs. 6.01%) and with clinicaly advanced CRC. Patients treated because of perforation had a five-fold higher 30 day mortality rate (9.09% vs. 1.83%), however long-term survival did not differ significantly in both groups. After resectional surgery in 874 patients an intestinal anastomosis was made. Anastomotic leakage was present in 23 (2.6%) patients. This complication occurred six-fold more frequently in a group of patients operated upon because of intestinal perforation (12.20% vs. 2.16%). In patients with CRC complicated with perforation of the colon in a 30-day observation significantly higher rate of complications and mortality was shown, whereas there was no difference in distant survival rates.

Endoscopic closure of septal perforations.

PubMed

Alobid, Isam

The management of septal perforations is a challenge for the surgeon. A wide variety of surgical techniques have been described, with different approaches. There is no scientific evidence to support a particular approach. The objective of this review is to present a practical guide on the technique of choice for each case of septal perforation. Inspection of the nasal mucosa, the size of the perforation, the location and especially the osteo-cartilaginous support, are the pillars of a successful surgery. For the sliding or rotating flaps of the mucosa of the septum it is essential to know in advance if the elevation of the mucopericondrio or mucoperiosteo of the septum is possible, otherwise the use of these flaps would not be indicated. The flaps of the lateral wall or nasal floor are the alternative. The pericranial flap may be indicated in total or near total perforations. The remnant of the nasal septum and status of osteo-cartilaginous support are the determining factors in the management of septal perforations. Each case should be evaluated individually and the approach chosen according to the size and location of the perforation, mucosal quality, personal history, previous surgery and the experience of the surgeon. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Intestinal perforation that developed after chemotherapy in a patient diagnosed with non-Hodgkin lymphoma: A case report and review of literature.

PubMed

Tatar, Cihad; Yavas, Mazlum; Akkus, Onder; Tapkan, Bahaeddin; Batikan, Oguz Kagan; Bayrak, Savas; Arikan, Soykan

2017-01-01

Non-Hodgkin Lymphomas (NHL) appear with the malign transformation of mature lymphocytes. Intestinal perforations are one of the most well-known complications of NHLs. In this review, a 29-year-old male patient who was diagnosed with NHL with gastrointestinal involvement that developed intestinal perforation after chemotherapy is presented. A 29-year-old male patient who received systemic chemotherapy in another healthcare center due to Major B-Cell Lymphoma was examined because he had stomachache after the treatment. The patient was urgently taken to operation. In the exploration, there were partly mass lesions in all small intestine segments. It was determined that one of the lesion was perforated. Small intestine resection was applied. The pathology report on resection material was reported as High Grade Major B-Cell Lymphoma. In the treatment of Lymphoma with intestinal B-Cells, there is no consensus because this disease is rarely observed. Perforation may appear as a complication of the chemotherapy. Depending on the steroids given to the patient, perforation may develop, and the clinical symptoms may be masked. It must be born in mind that there may be intestinal involvement in patients diagnosed with NHL, and intestinal perforation may develop due to chemotherapy. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Spontaneous asymptomatic gallbladder perforation

PubMed Central

Seçil, Mustafa

2014-01-01

Gallstone disease is common. However, a proportion of patients are asymptomatic and remain undiagnosed until the occurrence of complications. Common complications include acute cholecystitis, biliary obstruction, acute pancreatitis and cholangitis. Severe complications include gallbladder perforation, Mirizzi syndrome and fistula formation are usually associated with significant morbidity and mortality. We report a case of asymptomatic spotaneous gallbladder perforation due to acute cholecystitis. PMID:24914424

Dimensional scaling for impact cratering and perforation

NASA Technical Reports Server (NTRS)

Watts, Alan; Atkinson, Dale; Rieco, Steve

1993-01-01

This report summarizes the development of two physics-based scaling laws for describing crater depths and diameters caused by normal incidence impacts into aluminum and TFE Teflon. The report then describes equations for perforations in aluminum and TFE Teflon for normal impacts. Lastly, this report also studies the effects of non-normal incidence on cratering and perforation.

Prosthetic Management of Hard Palate Perforation in a Child with Acute Lymphoblastic Leukemia

PubMed Central

Chouksey, Gunjan C; Dholam, Kanchan P

2017-01-01

Palatal perforation is an uncommon complication seen in children with acute lymphoblastic leukemia undergoing chemotherapy. This may impact basic functions, such as speech, swallowing, chewing, affecting the quality of life (QOL). Prosthetic rehabilitation of the palatal perforation with obturator can optimally restore function, thereby improving and enhancing the QOL of these patients. PMID:28900336

Use of prototype two-channel endoscope with elevator enables larger lift-and-snare endoscopic mucosal resection in a porcine model

PubMed Central

Atkinson, Matthew; Chukwumah, Chike; Marks, Jeffrey; Chak, Amitabh

2014-01-01

Background: Flat and depressed lesions are becoming increasingly recognized in the esophagus, stomach, and colon. Various techniques have been described for endoscopic mucosal resection (EMR) of these lesions. Aims: To evaluate the efficacy of lift-grasp-cut EMR using a prototype dual-channel forward-viewing endoscope with an instrument elevator in one accessory channel (dual-channel elevator scope) as compared to standard dual-channel endoscopes. Methods: EMR was performed using a lift-grasp-cut technique on normal flat rectosigmoid or gastric mucosa in live porcine models after submucosal injection of 4 mL of saline using a dual-channel elevator scope or a standard dual-channel endoscope. With the dual-channel elevator scope, the elevator was used to attain further lifting of the mucosa. The primary endpoint was size of the EMR specimen and the secondary endpoint was number of complications. Results: Twelve experiments were performed (six gastric and six colonic). Mean specimen diameter was 2.27 cm with the dual-channel elevator scope and 1.34 cm with the dual-channel endoscope (P = 0.018). Two colonic perforations occurred with the dual-channel endoscope, vs no complications with the dual-channel elevator scope. Conclusions: The increased lift of the mucosal epithelium, through use of the dual-channel elevator scope, allows for larger EMR when using a lift-grasp-cut technique. Noting the thin nature of the porcine colonic wall, use of the elevator may also make this technique safer. PMID:24760237

Endoscopic observation of different repair patterns in human traumatic tympanic membrane perforations.

PubMed

Huang, Peng; Zhang, Shujun; Gong, Xinhong; Wang, Xuesong; Lou, Zi-Han

2017-08-03

In the last decade, there has been an increasing use of biomaterial patches in the regeneration of traumatic tympanic membrane perforations. The major advantages of biomaterial patches are to provisionally restore the physiological function of the middle ear, thereby immediately improving ear symptoms, and act as a scaffold for epithelium migration. However, whether there are additional biological effects on eardrum regeneration is unclear for biological material patching in the clinic. This study evaluated the healing response for different repair patterns in human traumatic tympanic membrane perforations by endoscopic observation. In total, 114 patients with traumatic tympanic membrane perforations were allocated sequentially to two groups: the spontaneous healing group (n=57) and Gelfoam patch-treated group (n=57). The closure rate, closure time, and rate of otorrhea were compared between the groups at 3 months. Ultimately, 107 patients were analyzed in the two groups (52 patients in the spontaneous healing group vs. 55 patients in the Gelfoam patch-treated group). The overall closure rate at the end of the 3 month follow-up period was 90.4% in the spontaneous healing group and 94.5% in the Gelfoam patch-treated group; the difference was not statistically significant (p>0.05). However, the total average closure time was significantly different between the two groups (26.8±9.1 days in the spontaneous healing group vs. 14.7±9.1 days in the Gelfoam patch-treated group, p<0.01). In addition, the closure rate was not significantly different between the spontaneous healing group and Gelfoam patch-treated group regardless of the perforation size. The closure time in the Gelfoam patch-treated group was significantly shorter than that in the spontaneous healing group regardless of the perforation size (small perforations: 7.1±1.6 days vs. 12.6±3.9, medium-sized perforations: 13.3±2.2 days vs. 21.8±4.2 days, and large perforations: 21.2±4.7 days vs. 38.4±5.7 days; p<0.01). In the regeneration of traumatic tympanic membrane perforations, Gelfoam patching not only plays a scaffolding role for epithelial migration, it also promotes edema and hyperplasia of granulation tissue at the edges of the perforation and accelerates eardrum healing. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Reconstruction of totally degloved fingers: a novel application of the bilobed spiraled innervated radial artery superficial palmar branch perforator flap design provides for primary donor-site closure.

PubMed

Chi, Zhenglin; Yang, Peng; Song, Dajiang; Li, Zan; Tang, Liang; Gao, Weiyang; Song, Yonghuan; Chu, Tingang

2017-05-01

To investigate the results of resurfacing completely degloved digits using bilobed innervated radial artery superficial palmar branch (RASPB) perforator flap in a spiral fashion. A detailed anatomic study on 30 adult fresh frozen cadavers preinjected with silicone rubber compound to demarcate arterial anatomy documented locations, numbers, and diameters of arteries and skin perforators with surrounding nerves. The flap-raising procedure was performed using four fresh cadaver specimen. We reviewed the reconstruction of 12 digits by using a bilobed spiraled innervated RASPB free perforator flap after non-replantable degloving injury. Two skin paddles were marked out using standard points of reference. At least two separate cutaneous perforator vessels were identified using a hand-held Doppler and were dissected back to the RASPB in retrograde fashion. The skin paddles were then divided between the two cutaneous perforators to provide two separate paddles with a common vascular supply. The skin paddles were stacked in a spiral fashion on the flap inset, effectively increasing the width of the flap to cover the totally degloved finger while still allowing closure of the primary donor-site. The RASPB was present within the flap in all cadavers. The direct perforator and the musculocutaneous perforator were available in 93.33 and 76.67 %, respectively, with neither of them in 6.67 % of the cases. The constantly present two perforators allowed the design of a new bilobed spiraled innervated radial artery superficial palmar branch perforator flap. We used the proposed flap to reconstruct completely degloved digits in 12 patients (mean age 28.6 years; range 17-35 years). With our proposed flap, no flap failure or re-exploration occurred and the donor site was closed primarily in all cases. All the flaps survived uneventfully. Total active motion ranged from 92° to 140° and 111° to 155° in the cases with and without metacarpophalangeal joint involvement, respectively. The static 2 point discrimination test varied from 6 to 11 mm. All the patients were satisfied with the overall results. The bilobed flap is large enough to cover totally degloved finger defects and contain direct skin perforators, provides a bespoke cover for complex soft tissue defects of completely degloved digits while also improving morbidity and cosmesis of the donor site. Level IV, retrospective series.

Impact of Right-Sided Aneurysm, Rupture Status, and Size of Aneurysm on Perforator Infarction Following Microsurgical Clipping of Posterior Communicating Artery Aneurysms with a Distal Transsylvian Approach.

PubMed

Tanabe, Jun; Ishikawa, Tatsuya; Moroi, Junta; Sakata, Yoshinori; Hadeishi, Hiromu

2018-03-01

Posterior communicating artery (PCoA) aneurysms are among the most common aneurysms. Because blockage of the PCoA and perforators can cause adverse outcomes, occlusion of these arteries by surgical clipping should be avoided. The impact of factors on PCoA perforator infarction when using a distal transsylvian approach for PCoA aneurysms was examined. A total of 183 patients underwent PCoA aneurysm clipping, excluding application of fenestrated clips. Patients were divided into 2 groups: patients with PCoA perforator infarction (infarction group) and patients without infarction (noninfarction group). Multiple factors were analyzed in the 2 groups. Twenty-two of the 183 patients (12.0%) showed perforator infarction, mainly on magnetic resonance imaging evaluation, resulting in permanent deficits in 2 patients (1.1%). The proportion of right-sided operations (86.4% vs. 53.4%; P = 0.005) and surgery for rupture (90.9% vs. 55.9%; P = 0.002) were significantly higher in the infarction group than in the noninfarction group. Aneurysms were significantly larger in the infarction group (8.4 ± 3.8 mm) than in the noninfarction group (6.3 ± 3.0 mm; P = 0.02). Ruptured status (odds ratio [OR], 7.35; P = 0.01), right side (OR, 5.19; P = 0.01), and aneurysm size (OR, 1.18; P = 0.02) remained independent predictors of perforator infarction on multivariate logistic regression analysis. Ruptured status, right side, and large PCoA aneurysm were independent predictors of PCoA perforator infarction. Symptoms due to PCoA perforating infarction were mostly transient and rarely affected outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

In vitro evaluation of the human gingival fibroblast/gingival mesenchymal stem cell dynamics through perforated guided tissue membranes: cell migration, proliferation and membrane stiffness assay.

PubMed

Gamal, A Y; Al-Berry, N N; Hassan, A A; Rashed, L A; Iacono, V J

2017-06-01

Migration of gingival fibroblasts/gingival mesenchymal stem cells through macro-perforated barrier membranes may allow them to participate positively in periodontal regeneration. The optimal guided tissue membrane perforation diameter that could favor maximum cell migration into the defect area and at the same time act as an occlusive barrier for gingival epithelium and its associated gingival extracellular matrix component is not yet identified. Cultured human gingival fibroblasts/gingival mesenchymal stem cells were placed in the upper chambers of 12-well collagen-coated polytetrafluoroethylene transwells, which were manually perforated with 0.2, 0.4 and 0.7 mm sized pores. The lower chambers of the transwells received blood clot as an attraction medium. The number of cells that have migrated to the lower chambers was calculated. Proliferation of these cells was evaluated using MTT assay. Scanning electron microscopy images were obtained for the lower surfaces of the transwell membranes. Perforated bovine collagen membranes (Tutopatch ® ) were subjected to mechanical testing to determine the tensile strength and modulus of elasticity. Group 3 (0.7 mm) showed significantly higher values for cell migration and proliferation. All groups showed a small degree of extracellular matrix migration through membrane perforations. Scanning electron microscopy evaluation revealed variable numbers of cells in fibrin matrices located mainly around the pore edges. There were non-significant differences between groups regarding mechanical properties. The present study demonstrated that macro-membrane perforations of 0.2, 0.4 and 0.7 mm are suitable pore diameters that could maintain membrane stiffness and allow for cellular migration. However, these membrane perforation diameters did not allow for total gingival connective tissue isolation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A comparative study of the incidence of Schneiderian membrane perforations during maxillary sinus augmentation with a sonic oscillating handpiece versus a conventional turbine handpiece.

PubMed

Geminiani, Alessandro; Weitz, Daniel S; Ercoli, Carlo; Feng, Changyong; Caton, Jack G; Papadimitriou, Dimitrios E V

2015-04-01

Sonic instruments may reduce perforation rates of the schneiderian membrane during lateral window sinus augmentation procedures. This study compares the incidence of membrane perforations using a sonic handpiece with an oscillating diamond insert versus a turbine handpiece with a conventional rotary diamond stone during lateral window sinus augmentation procedures. A retrospective chart analysis identified all lateral window sinus augmentation procedures done during a defined period. Among these procedures, those performed with a sonic handpiece and an oscillating diamond insert (experimental) and those performed with a conventional turbine and rotary diamond stone (conventional) were selected for this study. Reported occurrences of sinus membrane perforations during preparation of the osteotomy and elevation of the sinus membrane, as well as postoperative complications, were recorded and compared between treatment groups. Ninety-three consecutive patients were identified for a total of 130 sinus augmentation procedures (51 conventional, 79 experimental). Schneiderian membrane perforations were noted during preparation of the lateral window osteotomy in 27.5% of the sinuses in the conventional group and 12.7% of sinuses in the experimental group. During membrane elevation, perforations were noted in 43.1% of the sinuses in the conventional group and 25.3% of sinuses in the experimental group. Both differences in perforation rates were statistically significant (p < .05). There was no statistically significant difference in postoperative complications. In this study, the use of a sonic instrument to prepare the lateral window osteotomy during sinus elevation procedures resulted in a reduced perforation rate of the Schneiderian membrane compared with the conventional turbine instrument. © 2013 Wiley Periodicals, Inc.

Bilirubin provides perforator flap protection from ischaemia-reperfusion injury in a rat model: a preliminary result.

PubMed

Kim, Sung Young; Rah, Dong Kyun; Chong, Yosep; Lee, Song Hyun; Park, Tae Hwan

2016-10-01

The use of bilirubin, a well-known and powerful antioxidant, has gained popularity in recent years because of its role in the prevention of ischaemic heart disease in patients with Gilbert's syndrome. We investigate the effects of bilirubin on ischaemia-reperfusion (I/R) injury using a rat perforator flap model. Forty-eight rats were randomly divided into two groups: experimental (bilirubin) group (n = 24) and control group (n = 24). In each group, elevated bilateral deep inferior epigastric perforator (DIEP) flaps were created. The right (no ischaemia side) and left (ischaemia side) DIEP flaps were separated according to the presence of ischaemia induction. Ischaemia was induced in anaesthetised rats by perforator clamping for 15 or 30 minutes. After surgery, the flap survival was assessed daily on postoperative days 0 to 5, and overall histological changes of DIEP flaps above the perforator were analysed at postoperative day 5. The flap survival rate in the bilirubin group was significantly higher than that in the control group at the ischaemia side following perforator clamping for 15 or 30 minutes (93·42 ± 4·48% versus 89·63 ± 3·98%, P = 0·002; and 83·96 ± 4·23% versus 36·46 ± 6·38%, P < 0·001, respectively). The difference in flap survival between the two groups was the most prominent on the ischaemic side following 30 minutes of perforator clamping. From a morphologic perspective, pre-treatment with bilirubin was found to alleviate perforator flap necrosis caused by I/R injury in this experimental rat model. © 2015 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Exercise training prevents skeletal muscle damage in an experimental sepsis model

PubMed Central

Coelho, Carla Werlang; Jannig, Paulo R; de Souza, Arlete B; Fronza, Hercilio; Westphal, Glauco A; Petronilho, Fabricia; Constantino, Larissa; Dal-Pizzol, Felipe; Ferreira, Gabriela K; Streck, Emilio E; Silva, Eliezer

2013-01-01

OBJECTIVE: Oxidative stress plays an important role in skeletal muscle damage in sepsis. Aerobic exercise can decrease oxidative stress and enhance antioxidant defenses. Therefore, it was hypothesized that aerobic exercise training before a sepsis stimulus could attenuate skeletal muscle damage by modulating oxidative stress. Thus, the aim of this study was to evaluate the effects of aerobic physical preconditioning on the different mechanisms that are involved in sepsis-induced myopathy. METHODS: Male Wistar rats were randomly assigned to either the untrained or trained group. The exercise training protocol consisted of an eight-week treadmill program. After the training protocol, the animals from both groups were randomly assigned to either a sham group or a cecal ligation and perforation surgery group. Thus, the groups were as follows: sham, cecal ligation and perforation, sham trained, and cecal ligation and perforation trained. Five days after surgery, the animals were euthanized and their soleus and plantaris muscles were harvested. Fiber cross-sectional area, creatine kinase, thiobarbituric acid reactive species, carbonyl, catalase and superoxide dismutase activities were measured. RESULTS: The fiber cross-sectional area was smaller, and the creatine kinase, thiobarbituric acid reactive species and carbonyl levels were higher in both muscles in the cecal ligation and perforation group than in the sham and cecal ligation and perforation trained groups. The muscle superoxide dismutase activity was higher in the cecal ligation and perforation trained group than in the sham and cecal ligation and perforation groups. The muscle catalase activity was lower in the cecal ligation and perforation group than in the sham group. CONCLUSION: In summary, aerobic physical preconditioning prevents atrophy, lipid peroxidation and protein oxidation and improves superoxide dismutase activity in the skeletal muscles of septic rats. PMID:23420166

Utility of Immature Granulocyte Percentage in Pediatric Appendicitis

PubMed Central

Mathews, Eleanor K.; Griffin, Russell L.; Mortellaro, Vincent; Beierle, Elizabeth A.; Harmon, Carroll M.; Chen, Mike K.; Russell, Robert T.

2014-01-01

Background Acute appendicitis is the most common cause of abdominal surgery in children. Adjuncts are utilized to help clinicians predict acute or perforated appendicitis, which may affect treatment decisions. Automated hematologic analyzers can perform more accurate automated differentials including immature granulocyte percentages (IG%). Elevated IG% has demonstrated improved accuracy for predicting sepsis in the neonatal population than traditional immature to total neutrophil count (I/T) ratios. We intended to assess the additional discriminatory ability of IG% to traditionally assessed parameters in the differentiation between acute and perforated appendicitis. Materials and Methods We identified all patients with appendicitis from July 2012 to June 2013 by ICD-9 code. Charts were reviewed for relevant demographic, clinical, and outcome data, which were compared between acute and perforated appendicitis groups using Fischer’s exact and t-test for categorical and continuous variables, respectively. We utilized an adjusted logistic regression model utilizing clinical lab values to predict the odds of perforated appendicitis. Results 251 patients were included in the analysis. Those with perforated appendicitis had a higher white blood cell (WBC) count (p=0.0063), C-reactive protein (CRP) (p<0.0001), and IG% (p=0.0299). In the adjusted model, only elevated CRP (OR 3.46, 95% CI 1.40-8.54) and presence of left shift (OR 2.66, 95% CI 1.09-6.46) were significant predictors of perforated appendicitis. The c-statistic of the final model was 0.70, suggesting fair discriminatory ability in predicting perforated appendicitis. Conclusions IG% did not provide any additional benefit to elevated CRP and presence of left shift in the differentiation between acute and perforated appendicitis. PMID:24793450

Coronary Perforation Complicating Percutaneous Coronary Intervention in Patients With a History of Coronary Artery Bypass Surgery: An Analysis of 309 Perforation Cases From the British Cardiovascular Intervention Society Database.

PubMed

Kinnaird, Tim; Anderson, Richard; Ossei-Gerning, Nick; Cockburn, James; Sirker, Alex; Ludman, Peter; de Belder, Mark; Johnson, Thomas W; Copt, Samuel; Zaman, Azfar; Mamas, Mamas A

2017-09-01

The evidence base for coronary perforation (CP) occurring during percutaneous coronary intervention in patients with a history of coronary artery bypass surgery (PCI-CABG) is limited and the long-term effects unclear. Using a national PCI database, the incidence, predictors, and outcomes of CP during PCI-CABG were defined. Data were analyzed on all PCI-CABG procedures performed in England and Wales between 2005 and 2013. Multivariate logistic regressions and propensity scores were used to identify predictors of CP and its association with outcomes. During the study period, 309 CPs were recorded during 59 644 PCI-CABG procedures with the incidence rising from 0.32% in 2005 to 0.68% in 2013 ( P <0.001 for trend). Independent associates of perforation in native vessels included age, chronic occlusive disease intervention, rotational atherectomy use, number of stents, hypertension, and female sex. In graft PCI, predictors of perforation were history of stroke, New York Heart Association class, and number of stents used. In-hospital clinical complications including Q-wave myocardial infarction (2.9% versus 0.2%; P <0.001), major bleeding (14.0% versus 0.9%; P <0.001), blood transfusion (3.7% versus 0.2%; P <0.001), and death (10.0% versus 1.1%; P <0.001) were more frequent in patients with CP. A continued excess mortality occurred after perforation, with an odds ratio for 12-month mortality of 1.35 for perforation survivors compared with matched nonperforation survivors without a CP ( P <0.0001). CP is an infrequent event during PCI-CABG but is closely associated with adverse clinical outcomes. A legacy effect of perforation on 12-month mortality was observed. © 2017 American Heart Association, Inc.

Endovenous laser ablation of varicose perforating veins with the 1470-nm diode laser using the radial fibre slim.

PubMed

Zerweck, Christof; von Hodenberg, Eva; Knittel, Matthias; Zeller, Thomas; Schwarz, Thomas

2014-02-01

Endovenous Laser Ablation (EVLA) is one of the most accepted treatment options for varicose veins. The aim of this study was to investigate the efficacy and safety of the new radial fiber slim (ELVeS-radial-slim kit™) for the 1470 nm diode laser in perforator veins with a 1 month follow-up. Our prospective observational cohort study comprised 69 perforating veins in 55 patients. Ninety percent of all patients were in the CEAP-stage C3-C6. The radial fiber slim was used to occlude the perforating vein and the great or small saphenous vein in the same procedure. The primary efficacy endpoint of the study was ultrasonographically proven elimination of venous reflux in the perforating vein after at least one month. Secondary efficacy and further safety end points after one month were as follows: (1) sonographic exclusion of recanalization of the treated vein segments, (2) deep vein thrombosis (DVT), clinical pulmonary embolism (PE), or superficial vein thrombosis (SVT) as defined by objective testing, (3) death from any cause, (4) persistent clinical complaints such as pain and paresthesia. Follow-up could be completed in all patients. In all treated perforating varicose veins, occlusion with elimination of reflux could be demonstrated immediately after the procedure. After one month 95.6% of the treated veins were still occluded (67/69). During follow-up, we did not diagnose any DVT, PE or SVT in the area related to the treated perforating vein. No patient died. One patient reported paresthesia distally of the puncture site. Endovenous laser treatment of varicose perforating veins with 1470 nm diode laser using the radial fiber slim is effective and safe with low recanalization rates during 1-month follow-up.

A Prospective Study in Comparison of Ambulatory Phlebectomy and Duplex Guided Foam Sclerotherapy in the Management of Varicosities with Isolated Perforator Incompetence.

PubMed

Kishore, R; Sankar, T Bavani; Anandi, A; Nedunchezhian, S; Murugan, Valarmathy

2016-10-01

Perforators are those which connect the superficial and deep venous system either directly to main veins or indirectly through the muscular and soleal venous plexus. The emergence of minimally invasive techniques like ambulatory phlebectomy (AP) and foam sclerotherapy (FS) has led to increasing interest about the appropriate therapy for the treatment of isolated perforator incompetence. There have been no studies which have compared the effectiveness of these in-office procedures in isolated perforator incompetence due to the low prevalence of cases. The primary goal of this study is to compare the clinical parameters (return to normal activity, primary symptom relief), functional parameters (procedure time, change in disease severity, course of venous ulcer), and duplex parameters (recurrence in treated veins, complete occlusion of treated veins) in the management of leg varicosities having isolated primary perforator incompetence by ambulatory phlebectomy and duplex guided foam sclerotherapy. Though the procedure time was shorter with FS than AP, the other parameters of primary symptom relief such as change in disease severity, faster healing of venous ulcer, complete occlusion of treated veins in follow-up duplex examination, and lower recurrence of treated veins are better with AP than FS. In conclusion, the interruption of perforators is effective in decreasing the symptoms of chronic venous insufficiency and for the rapid healing of ulcers. The interruption of the incompetent perforating veins appears to be essential to decrease ambulatory venous hypertension. It is apparent from this study that ambulatory phlebectomy stands distinct with enormous benefits and serves as a superior alternative to foam sclerotherapy in treating patients with isolated perforator incompetence.

Quantitative analysis of tympanic membrane perforation: a simple and reliable method.

PubMed

Ibekwe, T S; Adeosun, A A; Nwaorgu, O G

2009-01-01

Accurate assessment of the features of tympanic membrane perforation, especially size, site, duration and aetiology, is important, as it enables optimum management. To describe a simple, cheap and effective method of quantitatively analysing tympanic membrane perforations. The system described comprises a video-otoscope (capable of generating still and video images of the tympanic membrane), adapted via a universal serial bus box to a computer screen, with images analysed using the Image J geometrical analysis software package. The reproducibility of results and their correlation with conventional otoscopic methods of estimation were tested statistically with the paired t-test and correlational tests, using the Statistical Package for the Social Sciences version 11 software. The following equation was generated: P/T x 100 per cent = percentage perforation, where P is the area (in pixels2) of the tympanic membrane perforation and T is the total area (in pixels2) for the entire tympanic membrane (including the perforation). Illustrations are shown. Comparison of blinded data on tympanic membrane perforation area obtained independently from assessments by two trained otologists, of comparative years of experience, using the video-otoscopy system described, showed similar findings, with strong correlations devoid of inter-observer error (p = 0.000, r = 1). Comparison with conventional otoscopic assessment also indicated significant correlation, comparing results for two trained otologists, but some inter-observer variation was present (p = 0.000, r = 0.896). Correlation between the two methods for each of the otologists was also highly significant (p = 0.000). A computer-adapted video-otoscope, with images analysed by Image J software, represents a cheap, reliable, technology-driven, clinical method of quantitative analysis of tympanic membrane perforations and injuries.

[The sural medial perforator flap: Anatomical bases, surgical technique and indications in head and neck reconstruction].

PubMed

Struk, S; Schaff, J-B; Qassemyar, Q

2018-04-01

The medial sural artery perforator (MSAP) flap is defined as a thin cutaneo-adipose perforator flap harvested on the medial aspect of the leg. The aims of this study were to describe the anatomical basis as well as the surgical technique and discuss the indications in head and neck reconstructive surgery. We harvested 10 MSAP flap on 5 fresh cadavers. For each case, the number and the location of the perforators were recorded. For each flap, the length of pedicle, the diameter of source vessels and the thickness of the flap were studied. Finally, we performed a clinical application of a MSAP flap. A total of 23 perforators with a diameter superior than 1mm were dissected on 10 legs. The medial sural artery provided between 1 and 4 musculocutaneous perforators. Perforators were located in average at 10.3cm±2cm from the popliteal fossa and at 3.6cm±1cm from the median line of the calf. The mean pedicle length was 12.1cm±2.5cm. At its origin, the source artery diameter was 1.8mm±0.25mm and source veins diameters were 2.45mm±0.9mm in average. There was no complication in our clinical application. This study confirms the reliability of previous anatomical descriptions of the medial sural artery perforator flap. This flap was reported as thin and particularly adapted for oral cavity reconstruction and for facial or limb resurfacing. Sequelae might be reduced as compared to those of the radial forearm flap with comparable results. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

PRESENTATION AND MANAGEMENT OF PERFORATED PEPTIC ULCER DISEASE IN A TERTIARY CENTRE IN SOUTH SOUTH NIGERIA.

PubMed

Dodiyi-Manuel, A; Wichendu, P N; Enebeli, V C

2015-01-01

Perforations of the stomach and duodenum are common complications of peptic ulcer disease (PUD), abuse of non steroidal anti inflammatory drugs (NSAIDS) and gastric cancer. Being a life threatening complication of PUD, it needs special attention with prompt resuscitation and appropriate surgical management if morbidity and mortality are to be avoided. To determine the pattern and management outcome of perforated peptic ulcer disease PUD as seen in University of Port Harcourt Teaching Hospital (UPTH), Port Harcourt, Rivers State, Nigeria). All the patients with perforated PUD that were managed at UPTH between January 2006 and December 2014 were studied. Relevant data were extracted from the case notes and analysed using the Statistical Package for Social Sciences (SPSS) version 17. Thirty six patients with perforated PUD were evaluated consisting of 28 males and 8 females with a male to female ratio of 3.5:1. Their ages ranged from 24 to 65 years with a mean of 42.1± 12.3 years and the peak age was at the third decade. After adequate resuscitation, all the patients had exploratory laparotomy. In 26 (72.2%) patients, the perforation was in the duodenum while in 10 (27.8%), it was in the stomach. Thirty two (88.9%) patients had Graham's omental patch repair of the perforation while simple closure only was done in 4 (11.1%) patients. Surgical site infection was the commonest post operative complication which was seen in 7 (19.4%) patients while 4 patients died giving a mortality rate of 11.1%. Perforated peptic ulcer predominantly affected young males and Graham's omental patch followed by Helicobacter pylori eradication was an effective treatment modality.

Ultrasound and Perforated Viscus; Dirty Fluid, Dirty Shadows, and Peritoneal Enhancement.

PubMed

Shokoohi, Hamid; S Boniface, Keith; M Abell, Bruce; Pourmand, Ali; Salimian, Mohammad

2016-01-01

Early detection of free air in the peritoneal cavity is vital in diagnosis of life-threatening emergencies, and can play a significant role in expediting treatment. We present a series of cases in which bedside ultrasound (US) in the emergency department accurately identified evidence of free intra-peritoneal air and echogenic (dirty) free fluid consistent with a surgical final diagnosis of a perforated hollow viscus. In all patients with suspected perforated viscus, clinicians were able to accurately identify the signs of pneumoperitoneum including enhanced peritoneal stripe sign (EPSS), peritoneal stripe reverberations, and focal air collections associated with dirty shadowing or distal multiple reflections as ring down artifacts. In all cases, hollow viscus perforation was confirmed surgically. It seems that, performing US in patients with suspected perforated viscus can accurately identify presence of intra-peritoneal echogenic or "dirty" free fluid as well as evidence of free air, and may expedite patient management.

Enhancement of local piezoelectric properties of a perforated ferroelectric thin film visualized via piezoresponse force microscopy

NASA Astrophysics Data System (ADS)

Ivanov, M. S.; Sherstyuk, N. E.; Mishina, E. D.; Khomchenko, V. A.; Tselev, A.; Mukhortov, V. M.; Paixão, J. A.; Kholkin, A. L.

2017-10-01

The local piezoresponse in a Ba0.8Sr0.2TiO3 epitaxial ferroelectric film perforated by cylindrical channels has been investigated experimentally by means of piezoresponse force microscopy (PFM). A large enhancement of the effective values for both lateral and vertical components of piezoelectric tensor was experimentally detected in the perforated film as compared to non-perforated structure—by a factor of 8 for the lateral and by a factor 2 for the vertical piezoresponse. This result is consistent with the previously reported enhancement of the optical second harmonic generation over perforated films observed in macroscopic experiments. We assume that a possible mechanism for the increased PFM response is due to reduction of stress and clamping in the film imposed by the substrate. The obtained insight is critical for understanding nanoscale piezo- and ferroelectric responses in photonic crystals fabricated by focused ion beam milling.

Acoustic impedance of micro perforated membranes: Velocity continuity condition at the perforation boundary.

PubMed

Li, Chenxi; Cazzolato, Ben; Zander, Anthony

2016-01-01

The classic analytical model for the sound absorption of micro perforated materials is well developed and is based on a boundary condition where the velocity of the material is assumed to be zero, which is accurate when the material vibration is negligible. This paper develops an analytical model for finite-sized circular micro perforated membranes (MPMs) by applying a boundary condition such that the velocity of air particles on the hole wall boundary is equal to the membrane vibration velocity (a zero-slip condition). The acoustic impedance of the perforation, which varies with its position, is investigated. A prediction method for the overall impedance of the holes and the combined impedance of the MPM is also provided. The experimental results for four different MPM configurations are used to validate the model and good agreement between the experimental and predicted results is achieved.

Two cases of bowel perforation associated with sunitinib treatment for renal cell carcinoma.

PubMed

Hoshino, Yoshinori; Hasegawa, Hirotoshi; Ishii, Yoshiyuki; Endo, Takashi; Ochiai, Hiroki; Okabayashi, Koji; Kaneko, Gou; Mikami, Shuji; Mukai, Makio; Oya, Mototsugu; Kitagawa, Yuko

2012-08-01

Sunitinib, a multitargeted tyrosine kinase inhibitor, is widely used in the treatment of carcinoma. Adverse events associated with this treatment, including fatigue, diarrhea, and hematotoxicity, have been reported in clinical trials. Bowel perforation is a surgical emergency that requires immediate treatment depending on the location and progression of the tumor. We report 2 cases of bowel perforation during sunitinib treatment. The patients presented with diffuse peritonitis, and emergency exploratory laparotomy was performed. We speculate that the underlying mechanisms were decrease in capillary density of the normal mucosa in case 1 and tumor shrinkage because of sunitinib treatment in case 2. To the best of our knowledge, this is the first study to report the pathological findings implicating bowel perforation due to sunitinib treatment. Further investigations are needed to clarify the risk factors for intestinal perforations associated with sunitinib treatment.

A case of perforating injury of eyeball and traumatic cataract caused by acupuncture

PubMed Central

Shuang, Han; Yichun, Kong

2016-01-01

Perforating globe injury is the leading cause of monocular blindness and vision loss. A 58-year-old male was injured by acupuncture needle during acupuncture treatment for his cerebral infarction. To the best of our knowledge, this is the first case report of perforating injury of the eyeball and traumatic cataract caused by acupuncture. The patient was hospitalized due to diagnosis of perforating ocular injury, traumatic cataract, and corneal and iris perforating injury. Moreover, he had to accept treatments of phacoemulsification, anterior vitrectomy along with intraocular lens implantation in the sulcus to improve his visual acuity. As acupuncture therapy has been widely performed for various diseases and achieved highly approval, the aim of this report is to remind acupuncturists operating accurately to avoid unnecessary injury during the treatment process, or the cure can also become the weapon. PMID:27221689

Corneal perforation after conductive keratoplasty with previous refractive surgery.

PubMed

Kymionis, George D; Titze, Patrik; Markomanolakis, Marinos M; Aslanides, Ioannis M; Pallikaris, Ioannis G

2003-12-01

A 56-year-old woman had conductive keratoplasty (CK) for residual hyperopia and astigmatism. Three years before the procedure, the patient had arcuate keratotomy, followed by laser in situ keratomileusis 2 years later for high astigmatism correction in both eyes. During CK, a corneal perforation occurred in the right eye; during the postoperative examination, an iris perforation and anterior subcapsule opacification were seen beneath the perforation site. The perforation was managed with a bandage contact lens and an antibiotic-steroid ointment; it had a negative Seidel sign by the third day. The surgery in the left eye was uneventful. Three months after the procedure, the uncorrected visual acuity was 20/32 and the best corrected visual acuity 20/20 in both eyes with a significant improvement in corneal topography. Care must be taken to prevent CK-treated spots from coinciding with areas in the corneal stroma that might have been altered by previous refractive procedures.

4H-SiC JFET Multilayer Integrated Circuit Technologies Tested Up to 1000 K

NASA Technical Reports Server (NTRS)

Spry, D. J.; Neudeck, P. G.; Chen, L.; Chang, C. W.; Lukco, D.; Beheim, G. M.

2015-01-01

Testing of semiconductor electronics at temperatures above their designed operating envelope is recognized as vital to qualification and lifetime prediction of circuits. This work describes the high temperature electrical testing of prototype 4H silicon carbide (SiC) junction field effect transistor (JFET) integrated circuits (ICs) technology implemented with multilayer interconnects; these ICs are intended for prolonged operation at temperatures up to 773K (500 C). A 50 mm diameter sapphire wafer was used in place of the standard NASA packaging for this experiment. Testing was carried out between 300K (27 C) and 1150K (877 C) with successful electrical operation of all devices observed up to 1000K (727 C).

Development of Scanning Ultrafast Electron Microscope Capability.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, Kimberlee Chiyoko; Talin, Albert Alec; Chandler, David W.

Modern semiconductor devices rely on the transport of minority charge carriers. Direct examination of minority carrier lifetimes in real devices with nanometer-scale features requires a measurement method with simultaneously high spatial and temporal resolutions. Achieving nanometer spatial resolutions at sub-nanosecond temporal resolution is possible with pump-probe methods that utilize electrons as probes. Recently, a stroboscopic scanning electron microscope was developed at Caltech, and used to study carrier transport across a Si p-n junction [ 1 , 2 , 3 ] . In this report, we detail our development of a prototype scanning ultrafast electron microscope system at Sandia National Laboratoriesmore » based on the original Caltech design. This effort represents Sandia's first exploration into ultrafast electron microscopy.« less

Integration of ZnO and CuO nanowires into a thermoelectric module

PubMed Central

Dalola, Simone; Faglia, Guido; Comini, Elisabetta; Ferroni, Matteo; Soldano, Caterina; Ferrari, Vittorio; Sberveglieri, Giorgio

2014-01-01

Summary Zinc oxide (ZnO, n-type) and copper oxide (CuO, p-type) nanowires have been synthesized and preliminarily investigated as innovative materials for the fabrication of a proof-of-concept thermoelectric device. The Seebeck coefficients, electrical conductivity and thermoelectric power factors (TPF) of both semiconductor materials have been determined independently using a custom experimental set-up, leading to results in agreement with available literature with potential improvement. Combining bundles of ZnO and CuO nanowires in a series of five thermocouples on alumina leads to a macroscopic prototype of a planar thermoelectric generator (TEG) unit. This demonstrates the possibility of further integration of metal oxide nanostructures into efficient thermoelectric devices. PMID:24991531

Integration of ZnO and CuO nanowires into a thermoelectric module.

PubMed

Zappa, Dario; Dalola, Simone; Faglia, Guido; Comini, Elisabetta; Ferroni, Matteo; Soldano, Caterina; Ferrari, Vittorio; Sberveglieri, Giorgio

2014-01-01

Zinc oxide (ZnO, n-type) and copper oxide (CuO, p-type) nanowires have been synthesized and preliminarily investigated as innovative materials for the fabrication of a proof-of-concept thermoelectric device. The Seebeck coefficients, electrical conductivity and thermoelectric power factors (TPF) of both semiconductor materials have been determined independently using a custom experimental set-up, leading to results in agreement with available literature with potential improvement. Combining bundles of ZnO and CuO nanowires in a series of five thermocouples on alumina leads to a macroscopic prototype of a planar thermoelectric generator (TEG) unit. This demonstrates the possibility of further integration of metal oxide nanostructures into efficient thermoelectric devices.

First Dark Matter Constraints from SuperCDMS Single-Charge Sensitive Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agnese, R.; et al.

We present the first limits on inelastic electron-scattering dark matter and dark photon absorption using a prototype SuperCDMS detector having a charge resolution of 0.1 electron-hole pairs (CDMS HVeV, a 0.93 gram CDMS HV device). These electron-recoil limits significantly improve experimental constraints on dark matter particles with masses as low as 1 MeV/more » $$\\mathrm{c^2}$$. We demonstrate a sensitivity to dark photons competitive with other leading approaches but using substantially less exposure (0.49 gram days). These results demonstrate the scientific potential of phonon-mediated semiconductor detectors that are sensitive to single electronic excitations.« less

CO2 Sensors Based on Nanocrystalline SnO2 Doped with CuO

NASA Technical Reports Server (NTRS)

Xu, Jennifer C.; Hunter, Gary W.; Liu, Chung Chiun; Ward, Benjamin J.

2008-01-01

Nanocrystalline tin oxide (SnO2) doped with copper oxide (CuO) has been found to be useful as an electrical-resistance sensory material for measuring the concentration of carbon dioxide in air. SnO2 is an n-type semiconductor that has been widely used as a sensing material for detecting such reducing gases as carbon monoxide, some of the nitrogen oxides, and hydrocarbons. Without doping, SnO2 usually does not respond to carbon dioxide and other stable gases. The discovery that the electrical resistance of CuO-doped SnO2 varies significantly with the concentration of CO2 creates opportunities for the development of relatively inexpensive CO2 sensors for detecting fires and monitoring atmospheric conditions. This discovery could also lead to research that could alter fundamental knowledge of SnO2 as a sensing material, perhaps leading to the development of SnO2-based sensing materials for measuring concentrations of oxidizing gases. Prototype CO2 sensors based on CuO-doped SnO2 have been fabricated by means of semiconductor-microfabrication and sol-gel nanomaterial-synthesis batch processes that are amendable to inexpensive implementation in mass production.

Inkjet-printing of non-volatile organic resistive devices and crossbar array structures

NASA Astrophysics Data System (ADS)

Sax, Stefan; Nau, Sebastian; Popovic, Karl; Bluemel, Alexander; Klug, Andreas; List-Kratochvil, Emil J. W.

2015-09-01

Due to the increasing demand for storage capacity in various electronic gadgets like mobile phones or tablets, new types of non-volatile memory devices have gained a lot of attention over the last few years. Especially multilevel conductance switching elements based on organic semiconductors are of great interest due to their relatively simple device architecture and their small feature size. Since organic semiconductors combine the electronic properties of inorganic materials with the mechanical characteristics of polymers, this class of materials is suitable for solution based large area device preparation techniques. Consequently, inkjet based deposition techniques are highly capable of facing preparation related challenges. By gradually replacing the evaporated electrodes with inkjet printed silver, the preparation related influence onto device performance parameters such as the ON/OFF ratio was investigated with IV measurements and high resolution transmission electron microscopy. Due to the electrode surface roughness the solvent load during the printing of the top electrode as well as organic layer inhomogeneity's the utilization in array applications is hampered. As a prototypical example a 1diode-1resistor element and a 2×2 subarray from 5×5 array matrix were fully characterized demonstrating the versatility of inkjet printing for device preparation.

CMOS Optoelectronic Lock-In Amplifier With Integrated Phototransistor Array.

PubMed

An Hu; Chodavarapu, Vamsy P

2010-10-01

We describe the design and development of an optoelectronic lock-in amplifier (LIA) for optical sensing and spectroscopy applications. The prototype amplifier is fabricated using Taiwan Semiconductor Manufacturing Co. complementary metal-oxide semiconductor 0.35-μm technology and uses a phototransistor array (total active area is 400 μm × 640μm) to convert the incident optical signals into electrical currents. The photocurrents are then converted into voltage signals using a transimpedance amplifier for subsequent convenient signal processing by the LIA circuitry. The LIA is optimized to be operational at 20-kHz modulation frequency but is operational in the frequency range from 13 kHz to 25 kHz. The system is tested with a light-emitting diode (LED) as the light source. The noise and signal distortions are suppressed with filters and a phase-locked loop (PLL) implemented in the LIA. The output dc voltage of the LIA is proportional to the incident optical power. The minimum measured dynamic reserve and sensitivity are 1.31 dB and 34 mV/μW, respectively. The output versus input relationship has shown good linearity. The LIA consumes an average power of 12.79 mW with a 3.3-V dc power supply.

Quantum interference measurement of spin interactions in a bio-organic/semiconductor device structure

DOE PAGES

Deo, Vincent; Zhang, Yao; Soghomonian, Victoria; ...

2015-03-30

Quantum interference is used to measure the spin interactions between an InAs surface electron system and the iron center in the biomolecule hemin in nanometer proximity in a bio-organic/semiconductor device structure. The interference quantifies the influence of hemin on the spin decoherence properties of the surface electrons. The decoherence times of the electrons serve to characterize the biomolecule, in an electronic complement to the use of spin decoherence times in magnetic resonance. Hemin, prototypical for the heme group in hemoglobin, is used to demonstrate the method, as a representative biomolecule where the spin state of a metal ion affects biologicalmore » functions. The electronic determination of spin decoherence properties relies on the quantum correction of antilocalization, a result of quantum interference in the electron system. Spin-flip scattering is found to increase with temperature due to hemin, signifying a spin exchange between the iron center and the electrons, thus implying interactions between a biomolecule and a solid-state system in the hemin/InAs hybrid structure. The results also indicate the feasibility of artificial bioinspired materials using tunable carrier systems to mediate interactions between biological entities.« less

Density functional calculations of multiphonon capture cross sections at defects in semiconductors

NASA Astrophysics Data System (ADS)

Barmparis, Georgios D.; Puzyrev, Yevgeniy S.; Zhang, X.-G.; Pantelides, Sokrates T.

2014-03-01

The theory of electron capture cross sections by multiphonon processes in semiconductors has a long and controversial history. Here we present a comprehensive theory and describe its implementation for realistic calculations. The Born-Oppenheimer and the Frank-Condon approximations are employed. The transition probability of an incoming electron is written as a product of an instantaneous electronic transition in the initial defect configuration and the line shape function (LSF) that describes the multiphonon processes that lead to lattice relaxation. The electronic matrix elements are calculated using the Projector Augmented Wave (PAW) method which yields the true wave functions while still employing a plane-wave basis. The LSF is calculated by employing a Monte Carlo method and the real phonon modes of the defect, calculated using density functional theory in the PAW scheme. Initial results of the capture cross section for a prototype system, namely a triply hydrogenated vacancy in Si are presented. The results are relevant for modeling device degradation by hot electron effects. This work is supported in part by the Samsung Advanced Institute of Technology (SAIT)'s Global Research Outreach (GRO) Program and by the LDRD program at ORNL.

Perforator Peroneal Artery Flap for Tongue Reconstruction.

PubMed

Chauhan, Shubhra; Chavre, Sachin; Chandrashekar, Naveen Hedne; B S, Naveen

2017-03-01

Reconstruction has evolved long way from primary closure to flaps. As time evolved, better understanding of vascularity of flap has led to the development of innovative reconstructive techniques. These flaps can be raised from various parts of the body for reconstruction and have shown least donor site morbidity. We use one such peroneal artery perforator flap for tongue reconstruction with advantage of thin pliable flap, minimal donor site morbidity and hidden scar. Our patient 57yrs old lady underwent wide local excision with selective neck dissection. Perforators are marked about 10 and 15 cm inferiorly from the fibular head using hand held Doppler. Leg is positioned in such a way to give better exposure during dissection of the flap and flap is harvested under a tourniquet with pressure kept 350 mm Hg. The perforator is kept at the eccentric location, so as to gain length of the pedicle. Skin incison is placed over the peroneal muscle and deepened unto the deep facia, then the dissection is continued over the muscle and the perforator arising from the lateral septum. The proximal perforator about 10 cm from the fibular head is a constant perforator and bigger one, which is traced up to the peroneal vessel. We could get a 6 cm of pedicle length. Finally the flap is islanded on this perforator and the pedicle is ligated and flap harvested. Anastamosis was done to the ipsilateral side to facial vessels. The donor site is closed primarily and in the upper half one can harvest 5 cm width flap without requiring a skin graft along with a length of 8 to 12 cm. Various local and free flap has been used for reconstruction of partial tongue defects with its obvious donor site problems, like less pliable skin and not so adequate tissue from local flaps and sacrificing a important artery as in radial forearm flap serves as the work horse in reconstruction of partial tongue defects, Concept of super microsurgery was popularized by Japanese in 1980s and the concept of angiosome proposed by Taylor paved the way for development of new flaps. True perforator flaps are those where the source vessel is left undisturbed and overlying skin flap is raised. Yoshimura proposed cutaneous flap could be raised from peroneal artery (Br J Plast Surg 42:715-718, 1989). Wolff et al. (Plast Reconstr Surg 113:107-113, 2004) first used perforator based peroneal artery flap for oral reconstruction. Location of perforators vary, hence pre operative localisation can be done by ultrasound doppler, CT angio or MR angiography. Disadvantages over radial flap include varying anatomic location of perforators, need for imaging and difficult dissection of delicate vessels through muscles and hence a learning curve. Our patient had an arterial thrombus within few hours post-operatively which was successfully salvaged with immediate re-exploration and re-anastomosis of artery. Post-operative healing was uneventful and donor site was closed primarily without the need for graft. Perforator peroneal flap serves as a useful armamentarium for reconstruction of moderate size defects of tongue, buccal mucosa and floor of mouth with advantages of thin pliable flap, minimal donor site morbidity and hidden scar.

High power laser perforating tools and systems

DOEpatents

Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

2014-04-22

ystems devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser perforation of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to perforate such boreholes.

Perforated-Layer Implementation Of Radio-Frequency Lenses

NASA Technical Reports Server (NTRS)

Dolgin, Benjamin P.

1996-01-01

Luneberg-type radio-frequency dielectric lenses made of stacked perforated circular dielectric sheets, according to proposal. Perforation pattern designed to achieve required spatial variation of permittivity. Consists of round holes distributed across face of each sheet in "Swiss-cheese" pattern, plus straight or curved slots that break up outer parts into petals in "daisy-wheel" pattern. Holes and slots made by numerically controlled machining.

Acute gall bladder perforation--a dilemma in early diagnosis.

PubMed Central

Ong, C L; Wong, T H; Rauff, A

1991-01-01

Gall bladder perforation is a rare complication of cholecystitis. A definitive diagnosis is uncommon before surgery and the morbidity and mortality associated with this condition are high. We report six patients with gall bladder perforation to show the difficulty of making an early diagnosis. The history and the clinical findings of these patients are reviewed to highlight diagnostic pitfalls. PMID:1885081

Migration of a Central Venous Catheter in a Hemodialysis Patient Resulted in Left Atrial Perforation and Thrombus Formation Requiring Open Heart Surgery.

PubMed

Wong, Kevin; Marks, Barry A; Qureshi, Anwer; Stemm, Joseph J

2016-07-01

Central venous catheterization is widely used in patients on hemodialysis. A rare complication associated with the clinical use of central venous catheters is perforation of the heart or major vessels. We report a case of inadvertent perforation of the left atrium and thrombosis after the placement of a hemodialysis catheter in the right internal jugular vein. In such cases, surgical removal of the central venous catheter from perforation sites in the heart and vessel walls poses anesthetic challenges because of the high risk of pneumothorax, hemorrhage, arrhythmias, thrombosis, and death.

Reconstruction of pressure sores with perforator-based propeller flaps.

PubMed

Jakubietz, Rafael G; Jakubietz, Danni F; Zahn, Robert; Schmidt, Karsten; Meffert, Rainer H; Jakubietz, Michael G

2011-03-01

Perforator flaps have been successfully used for reconstruction of pressure sores. Although V-Y advancement flaps approximate debrided wound edges, perforator-based propeller flaps allow rotation of healthy tissue into the defect. Perforator-based propeller flaps were planned in 13 patients. Seven pressure sores were over the sacrum, five over the ischial tuberosity, and one on the tip of the scapula. Three patients were paraplegic, six were bedridden, and five were ambulatory. In three patients, no perforators were found. In 10 patients, propeller flaps were transferred. In two patients, total flap necrosis occurred, which was reconstructed with local advancement flaps. In two cases, a wound dehiscence occurred and had to be revised. One hematoma required evacuation. No further complications were noted. No recurrence at the flap site occurred. Local perforator flaps allow closure of pressure sores without harvesting muscle. The propeller version has the added benefit of transferring tissue from a distant site, avoiding reapproximation of original wound edges. Twisting of the pedicle may cause torsion and venous obstruction. This can be avoided by dissecting a pedicle of at least 3 cm. Propeller flaps are a safe option for soft tissue reconstruction of pressure sores. © Thieme Medical Publishers.

Reconstruction of Heel With Propeller Flap in Postfasciotomy and Popliteal Artery Revascularization State.

PubMed

Kang, Jin Seok; Choi, Hwan Jun; Tak, Min Sung

2016-06-01

Free flaps are still the gold standard for large defects of the lower limb, but propeller perforator flaps have become a simpler and faster alternative to free flaps because of some advantages such as reliable vascular pedicle, wide mobilization and rotation, great freedom in design, low donor site morbidity, and easy harvest with no requirement for anastomosis. But when the vessels show insufficient findings in preoperative evaluation using a Doppler probe or the vessel is injured, the surgeon should avoid performing free flap surgery to prevent flap failure and should select a propeller perforator flap as an alternative method on the condition that more than one perforator is intact. In this study, we report reconstruction of soft tissue defects of the heel with a pedicled propeller flap in postfasciotomy and popliteal artery revascularization state by making an incision on the central portion above the Achilles tendon, which can be covered by the posterior tibial artery perforator or the peroneal artery perforator based flaps. In conclusion, we showed that although the popliteal artery was injured, the soft tissue defect can be reconstructed using a perforator propeller flap if intact distal flow in the anastomosis site was confirmed. © The Author(s) 2015.

Experimental and Theoretical Analysis of Sound Absorption Properties of Finely Perforated Wooden Panels

PubMed Central

Song, Boqi; Peng, Limin; Fu, Feng; Liu, Meihong; Zhang, Houjiang

2016-01-01

Perforated wooden panels are typically utilized as a resonant sound absorbing material in indoor noise control. In this paper, the absorption properties of wooden panels perforated with tiny holes of 1–3 mm diameter were studied both experimentally and theoretically. The Maa-MPP (micro perforated panels) model and the Maa-Flex model were applied to predict the absorption regularities of finely perforated wooden panels. A relative impedance comparison and full-factorial experiments were carried out to verify the feasibility of the theoretical models. The results showed that the Maa-Flex model obtained good agreement with measured results. Control experiments and measurements of dynamic mechanical properties were carried out to investigate the influence of the wood characteristics. In this study, absorption properties were enhanced by sound-induced vibration. The relationship between the dynamic mechanical properties and the panel mass-spring vibration absorption was revealed. While the absorption effects of wood porous structure were not found, they were demonstrated theoretically by using acoustic wave propagation in a simplified circular pipe with a suddenly changed cross-section model. This work provides experimental and theoretical guidance for perforation parameter design. PMID:28774063

Experimental Studies on Wave Interactions of Partially Perforated Wall under Obliquely Incident Waves

PubMed Central

Lee, Jong-In; Kim, Young-Taek; Shin, Sungwon

2014-01-01

This study presents wave height distribution in terms of stem wave evolution phenomena on partially perforated wall structures through three-dimensional laboratory experiments. The plain and partially perforated walls were tested to understand their effects on the stem wave evolution under the monochromatic and random wave cases with the various wave conditions, incident angle (from 10 to 40 degrees), and configurations of front and side walls. The partially perforated wall reduced the relative wave heights more effectively compared to the plain wall structure. Partially perforated walls with side walls showed a better performance in terms of wave height reduction compared to the structure without the side wall. Moreover, the relative wave heights along the wall were relatively small when the relative chamber width is large, within the range of the chamber width in this study. The wave spectra showed a frequency dependency of the wave energy dissipation. In most cases, the existence of side wall is a more important factor than the porosity of the front wall in terms of the wave height reduction even if the partially perforated wall was still effective compared to the plain wall. PMID:25254260

Experimental studies on wave interactions of partially perforated wall under obliquely incident waves.

PubMed

Lee, Jong-In; Kim, Young-Taek; Shin, Sungwon

2014-01-01

This study presents wave height distribution in terms of stem wave evolution phenomena on partially perforated wall structures through three-dimensional laboratory experiments. The plain and partially perforated walls were tested to understand their effects on the stem wave evolution under the monochromatic and random wave cases with the various wave conditions, incident angle (from 10 to 40 degrees), and configurations of front and side walls. The partially perforated wall reduced the relative wave heights more effectively compared to the plain wall structure. Partially perforated walls with side walls showed a better performance in terms of wave height reduction compared to the structure without the side wall. Moreover, the relative wave heights along the wall were relatively small when the relative chamber width is large, within the range of the chamber width in this study. The wave spectra showed a frequency dependency of the wave energy dissipation. In most cases, the existence of side wall is a more important factor than the porosity of the front wall in terms of the wave height reduction even if the partially perforated wall was still effective compared to the plain wall.

Coagulation syndrome: Delayed perforation after colorectal endoscopic treatments

PubMed Central

Hirasawa, Kingo; Sato, Chiko; Makazu, Makomo; Kaneko, Hiroaki; Kobayashi, Ryosuke; Kokawa, Atsushi; Maeda, Shin

2015-01-01

Various procedure-related adverse events related to colonoscopic treatment have been reported. Previous studies on the complications of colonoscopic treatment have focused primarily on perforation or bleeding. Coagulation syndrome (CS), which is synonymous with transmural burn syndrome following endoscopic treatment, is another typical adverse event. CS is the result of electrocoagulation injury to the bowel wall that induces a transmural burn and localized peritonitis resulting in serosal inflammation. CS occurs after polypectomy, endoscopic mucosal resection (EMR), and even endoscopic submucosal dissection (ESD). The occurrence of CS after polypectomy or EMR varies according previous reports; most report an occurrence rate around 1%. However, artificial ulcers after ESD are largely theoretical, and CS following ESD was reported in about 9% of cases, which is higher than that for CS after polypectomy or EMR. Most cases of post-polypectomy syndrome (PPS) have an excellent prognosis, and they are managed conservatively with medical therapy. PPS rarely develops into delayed perforation. Delayed perforation is a severe adverse event that often requires emergency surgery. Since few studies have reported on CS and delayed perforation associated with CS, we focused on CS after colonoscopic treatments in this review. Clinicians should consider delayed perforation in CS patients. PMID:26380051

Percutaneous drainage in conservative therapy for perforated gastroduodenal ulcers.

PubMed

Oida, Takatsugu; Kano, Hisao; Mimatsu, Kenji; Kawasaki, Atsushi; Kuboi, Youichi; Fukino, Nobutada; Kida, Kazutoshi; Amano, Sadao

2012-01-01

The management of peptic ulcers has dramatically changed and the incidence of elective surgery for gastroduodenal peptic ulcers has markedly decreased; hence, the incidence of emergency surgery for perforated peptic ulcers has slightly increased. In select cases, conservative therapy can be used as an alternative for treating perforated gastroduodenal ulcers. In this study, we evaluated the efficacy of percutaneous abdominal drainage for the conservative treatment of perforated gastroduodenal ulcers. We retrospectively studied 51 patients who had undergone conservative therapy for perforated gastroduodenal ulcers. These patients were divided into 2 groups on the basis of the initial treatment with conservative therapy with or without percutaneous drainage: group PD included patients who had undergone percutaneous drainage and group NPD, patients who had undergone non-percutaneous drainage. In the PD group, 14.3% (n=3) of the patients did not respond to conservative therapy, while this value was 43.3% (n=13) in the NPD group. The 2 groups differed significantly with respect to conversion from conservative therapy to surgery (p<0.0352). Conservative therapy for perforated gastroduodenal ulcers should be performed only in the case of patients meeting the required criteria; its combination with percutaneous intraperitoneal drainage is effective as initial conservative therapy.

Perforated peptic ulcer disease in Zewditu Hospital.

PubMed

Asefa, Zelalem; G/eyesus, Awetash

2012-04-01

Peptic ulcer perforation is a serious complication of peptic ulcer disease with a significant morbidity and mortality. To evaluate 76 patients operated for peptic ulcer perforation and analyse the associated factors in Zewditu Memorial Hospital, Addis Ababa from September 2006 to August 2008. A retrospective analysis of medical records of 76 patients who were operated up on for perforated peptic ulcer over a two year period (2006-2008). The male to female ratio was 6.6:1 with a mean age being 31.5 years. The most common presenting symptom was abdominal pain in 76 (100%) patients. History of smoking and khat chewing was documented in 53/64 (82.8%) and 48/64 (75%) of the patients respectively. Twenty five per cent of the patients gave no history of previous peptic ulcer disease. Seventy patients (92.1%) presented after 48 hours of their illness. The mean hospital stay was 14.5 days. Leucocytosis was found in 31.6% of the cases. Sixty five (85.5%) patients had duodenal ulcer perforation. Postoperative complications occurred in 24 (31.6%) patients. Twelve (15.8%) patients died in the hospital. Early presentation of patients and change in life style may reduce morbidity and mortality in patients with peptic ulcer perforation.

Skull reconstruction after resection of bone tumors in a single surgical time by the association of the techniques of rapid prototyping and surgical navigation.

PubMed

Anchieta, M V M; Salles, F A; Cassaro, B D; Quaresma, M M; Santos, B F O

2016-10-01

Presentation of a new cranioplasty technique employing a combination of two technologies: rapid prototyping and surgical navigation. This technique allows the reconstruction of the skull cap after the resection of a bone tumor in a single surgical time. The neurosurgeon plans the craniotomy previously on the EximiusMed software, compatible with the Eximius Surgical Navigator, both from the company Artis Tecnologia (Brazil). The navigator imports the planning and guides the surgeon during the craniotomy. The simulation of the bone fault allows the virtual reconstruction of the skull cap and the production of a personalized modelling mold using the Magics-Materialise (Belgium)-software. The mold and a replica of the bone fault are made by rapid prototyping by the company Artis Tecnologia (Brazil) and shipped under sterile conditions to the surgical center. The PMMA prosthesis is produced during the surgical act with the help of a hand press. The total time necessary for the planning and production of the modelling mold is four days. The precision of the mold is submillimetric and accurately reproduces the virtual reconstruction of the prosthesis. The production of the prosthesis during surgery takes until twenty minutes depending on the type of PMMA used. The modelling mold avoids contraction and dissipates the heat generated by the material's exothermic reaction in the polymerization phase. The craniectomy is performed with precision over the drawing made with the help of the Eximius Surgical Navigator, according to the planned measurements. The replica of the bone fault serves to evaluate the adaptation of the prosthesis as a support for the perforations and the placement of screws and fixation plates, as per the surgeon's discretion. This technique allows the adequate oncologic treatment associated with a satisfactory aesthetic result, with precision, in a single surgical time, reducing time and costs.

Perforator and secondary branch origin in relation to the neck of saccular, cerebral bifurcation aneurysms.

PubMed

Pritz, Michael B

2014-11-01

Perforator and secondary branch origin in relation to the neck of cerebral, saccular bifurcation aneurysms were analyzed. These two features were considered important for treatment. From a series of microsurgically clipped saccular cerebral aneurysms, 142 bifurcation aneurysms had detailed imaging studies and operative records that could be analyzed. The incidence of perforator origin from the aneurysm neck was as follows: basilar, 1/15 (7%); internal carotid artery bifurcation, 4/23 (17%); main stem of the middle cerebral artery/secondary branch of the middle cerebral artery, 6/52 (12%); anterior communicating artery region, 5/46 (11%); and distal bifurcation vessels, 0/6 (0%). Aneurysms arising from the anterior communicating artery between the anterior cerebral arteries had a high incidence of perforator origin from the aneurysm neck. The location of secondary branch origin from the aneurysm neck varied depending on the aneurysm group. Perforator origin from the aneurysm neck was infrequent. A subgroup of anterior communicating artery region aneurysms had a high incidence of perforator origin from the aneurysm neck. Although protection of these neck perforators will be difficult, their identification may be even more challenging. Secondary branch origin from the aneurysm neck varied depending on the aneurysm group. Advanced endovascular techniques are needed to obliterate aneurysms in which the secondary branch(es) arise from the aneurysm neck. If this is not possible, craniotomy and clip ligation will be required if complete aneurysm obliteration is the goal. Copyright © 2014 Elsevier Inc. All rights reserved.

The Anterior Interosseus Artery Perforator Flap: Anatomical Dissections and Clinical Study

PubMed Central

Panse, Nikhil S; Joshi, Sheetal B; Sahasrabudhe, Parag B; Bahetee, B; Gurude, Pradnya; Chandanwale, Ajay

2017-01-01

BACKGROUND Reconstruction of upper extremity deformities continues to be a challenge to the reconstructive surgeon. Various loco regional, distant and free flaps are available for reconstruction. However, each has its own set of advantages and disadvantages. Of the commonly performed local flaps, radial artery forearm flap, and the posterior interosseus artery flap stand out prominently. Recently, perforator propeller flaps have been used for resurfacing the upper extremity. The anterior interosseus artery perforator flap is an uncommonly used and described flap. METHODS This study was divided into anatomical study and clinical application in a IV level of evidence. In the anatomical study, five upper extremities were studied. Clinically, 12 patients underwent reconstruction using the anterior interosseus artery perforator flap. Flaps were performed by a single surgeon. A retrospective review of these cases from November 2008 to May 2014 is presented. RESULTS The anterior interosseus artery perforator was identified in four out of five cadaver limbs. The septocutaneous perforator was in the fifth extensor compartment around 4 cm proximal to the wrist joint. Of the twelve flaps, there was complete necrosis in one flap, and partial necrosis in one flap. The patient with complete necrosis underwent skin grafting at a later date. The wound healed secondarily in case of partial flap necrosis. CONCLUSION Anterior interosseus artery perforator flap must be considered as an important reconstructive option in the armamentarium of the plastic surgeon, while managing hand and wrist defects. PMID:28713704

[Perforated peptic ulcer: is the form of methamphetamine known as "crystal meth" a new risk factor?].

PubMed

Martínez-Aguirre, A E; Romero-Mejía, C; Chacón-Cruz, E

2012-01-01

The emergence of new synthetic drugs related to peptic ulcer perforation has been reported. Recently an increase in the use of inhaled methamphetamine has been observed and we have described an association of frequent use with peptic disease symptomatology and perforation. To determine whether methamphetamine use is a factor related to peptic acid disease and perforation and to establish its demographic variables. A retrospective, comparative, descriptive, and observational study was carried out through the evaluation of medical records of patients admitted to the Surgery Service with perforated ulcer, within the time frame of January 2002 to March 2005. A descriptive analysis was carried out, along with the Z test, odds ratio, confidence interval, p value and the Student's t test. Forty-two patients were divided into 2 groups: methamphetamine users (n=25) and nonusers (n=17). There was a statistically significant difference in relation to age, which was lower in the methamphetamine user group (38,7 years vs 58,88 years, p=0.0001). In addition, there was a trend in the user group to develop peptic ulcer perforation at earlier ages compared with the nonuser group (p=0.0001). There were no statistically significant differences between the two groups in regard to clinical presentation. Methamphetamine use is related to ulcer perforation in age groups of younger patients when compared with nonuser patients. Copyright © 2011. Published by Masson Doyma México S.A.

Colorectal cancer with intestinal perforation – a retrospective analysis of treatment outcomes

PubMed Central

Woda, Łukasz; Tojek, Krzysztof; Jarmocik, Paweł; Jawień, Arkadiusz

2014-01-01

Aim of the study Colorectal cancer (CRC) is one of the leading cause of death in European population. It progresses without any symptoms in the early stages or those clinical symptoms are very discrete. The aim of this study was a retrospective analysis of treatment outcomes in patients with colorectal cancer complicated with intestinal perforation. Material and methods A retrospective analysis of patients urgently operated upon in our Division of General Surgery, because of large intestine perforation, from February 1993 to February 2013 has been made. Results were compared with a group of patients undergoing the elective surgery for colorectal cancer in the same time and Division. Results Intestinal perforation occurred more often in males (6.52% vs. 6.03%), patients with mucous component in histopathological examination (9.09% vs. 6.01%) and with clinicaly advanced CRC. Patients treated because of perforation had a five-fold higher 30 day mortality rate (9.09% vs. 1.83%), however long-term survival did not differ significantly in both groups. After resectional surgery in 874 patients an intestinal anastomosis was made. Anastomotic leakage was present in 23 (2.6%) patients. This complication occurred six-fold more frequently in a group of patients operated upon because of intestinal perforation (12.20% vs. 2.16%). Conclusions In patients with CRC complicated with perforation of the colon in a 30-day observation significantly higher rate of complications and mortality was shown, whereas there was no difference in distant survival rates. PMID:25784840

Safely combining abdominoplasty with aggressive abdominal liposuction based on perforator vessels: technique and a review of 300 consecutive cases.

PubMed

Smith, Lane F; Smith, Lane F

2015-05-01

There continues to be controversy about performing abdominoplasty concurrently with abdominal liposuction. The concern is that liposuction on the already vascularly compromised abdominal flap will lead to increased complications and flap necrosis. The central abdomen is supplied by the epigastric system. If perforator vessels from this system are spared, the blood supply to the abdomen can be spared and liposuction should be able to be safely performed on the elevated abdominal flap. The purpose of this study was to evaluate the safety of abdominoplasty with concurrent abdominal liposuction when a perforator vessel is spared. A standard abdominoplasty was performed, sparing one or two perforator vessels from the deep superior epigastric artery system. A retrospective chart review of 300 consecutive patients who underwent abdominoplasty surgery combined with concurrent abdominal liposuction was performed. Complications, total volume of abdominal liposuction, and results were reviewed. The overall complication rate was 17.3 percent (52 patients). Sixteen percent (48 patients) suffered minor complications and 1.3 percent (four patients) suffered major complications. Abdominoplasty can be combined safely with concurrent abdominal liposuction when a perforator vessel is spared. The combination of concurrent liposuction with abdominoplasty showed no increase in complication rates when a perforator vessel was spared. The perforator vessels are located consistently in a 2-cm radius located 4 cm from the midline and 6 cm from the subcostal margin. The potential advantages of abdominoplasty with concurrent liposuction include a better postoperative cosmetic result. Therapeutic, IV.

Endothelial reaction to perforating and non-perforating excimer laser excisions in rabbits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koch, J.W.; Lang, G.K.; Naumann, G.O.

1991-05-01

With an ArF excimer laser (193 nm, 750 mJ/cm2, 20 Hz) and a special slit-mask system, perforating and non-perforating linear keratectomies were performed in 55 rabbit corneas with a follow-up from 1 hour to 6 months. Varying the pulse number according to ablation rate (0.8 micron/pulse) and corneal thickness, four linear radial excisions (3 mm length, 70 microns width) of increasing depth (70%, 80%, 90%, 100% perforation) were produced. The corneas were processed for light microscopy, scanning and transmission electron microscopy, and vital staining of the endothelium. Except for mild cell contact alterations and discrete single cell damage in themore » 90% deep excisions, no endothelial damage could be detected after non-perforating keratectomies. Minute (less than 20 microns) and small (20 to 100 microns maximal diameter) perforations induced cell enlargement, formation of pseudopodia, rosette-like figures, multi-nucleated giant cells, and ultimately uniform reformation of the cell pattern (1 hour to 7 days postoperatively). Larger excimer laser defects of Descemet's membrane (greater than 100 microns) were overgrown by dedifferentiated endothelial cells producing a new PAS-positive basement membrane. Vital staining revealed the complete and stable reorganization of the endothelium over these lesions within 6 months. The authors observations are similar to those reported on the endothelial repair process following other surgical manipulations (knife incisions, direct Nd:YAG-laser trauma) and support the applicability of excimer lasers for corneal trephination in patients.« less

Fast track pathway for perforated appendicitis.

PubMed

Frazee, Richard; Abernathy, Stephen; Davis, Matthew; Isbell, Travis; Regner, Justin; Smith, Randall

2017-04-01

Perforated appendicitis is associated with an increased morbidity and length of stay. "Fast track" protocols have demonstrated success in shortening hospitalization without increasing morbidity for a variety of surgical processes. This study evaluates a fast track pathway for perforated appendicitis. In 2013, a treatment pathway for perforated appendicitis was adopted by the Acute Care Surgery Service for patients having surgical management of perforated appendicitis. Interval appendectomy was excluded. Patients were treated initially with intravenous antibiotics and transitioned to oral antibiotics and dismissed when medically stable and tolerating oral intake. A retrospective review of patients managed on the fast track pathway was undertaken to analyze length of stay, morbidity, and readmissions. Thirty-four males and twenty-one females with an average age of 46.8 years underwent laparoscopic appendectomy for perforated appendicitis between January 2013 and December 2014. Pre-existing comorbidities included hypertension 42%, diabetes mellitus 11%, COPD 5% and heart disease 2%. No patient had conversion to open appendectomy. Average length of stay was 2.67 days and ranged from 1 to 12 days (median 2 days). Postoperative morbidity was 20% and included abscess (6 patients), prolonged ileus (3 patients), pneumonia (1 patient), and congestive heart failure (1 patient). Five patients were readmitted for abscess (3 patients), congestive heart failure (1 patient), and pneumonia (1 patient). A fast track pathway for perforated appendicitis produced shorter length of stay and acceptable postoperative morbidity and readmission. This offers the potential for significant cost savings over current national practice patterns. Copyright © 2016 Elsevier Inc. All rights reserved.

Management of Pediatric Perforated Appendicitis: Comparing Outcomes Using Early Appendectomy Versus Solely Medical Management.

PubMed

Bonadio, William; Rebillot, Katie; Ukwuoma, Onyinyechi; Saracino, Christine; Iskhakov, Arthur

2017-10-01

There is controversy regarding whether children with perforated appendicitis should receive early appendectomy (EA) versus medical management (MM) with antibiotics and delayed interval appendectomy. The objective of this study was to compare outcomes of children with perforated appendicitis who receive EA versus MM. Case review of consecutive children <18 years of age with perforated appendicitis who received either EA or MM during an 8-year period. Criteria for hospital discharge included patient being afebrile for at least 24 hours, pain-free and able to tolerate oral intake. Of 203 patients diagnosed with perforated appendicitis, 122 received EA and 81 received MM. All received parenteral antibiotic therapy initiated in the emergency department and continued during hospitalization. There were no significant differences between groups in mean patient age, mean complete blood count total white blood cells count, gender distribution, rates of emergency department fever or rates of intra-abdominal infection (abscess or phlegmon) identified on admission. Compared with patients receiving MM, those receiving EA experienced significantly fewer (1) days of hospitalization, parenteral antibiotic therapy and in-hospital fever; (2) radiographic studies, percutaneous drainage procedures and placement of central venous catheters performed; (3) post admission intra-abdominal complications and (4) unscheduled repeat hospitalizations after hospital discharge. Only 1 EA-managed patient developed a postoperative wound infection. Children with perforated appendicitis who receive EA experience significantly less morbidity and complications versus those receiving MM. The theoretical concern for enhanced morbidity associated with EA management of perforated appendicitis is not supported by our analysis.

Study of multipactor suppression of microwave components using perforated waveguide technology for space applications

NASA Astrophysics Data System (ADS)

Ye, Ming; Li, Yun; He, Yongning; Daneshmand, Mojgan

2017-05-01

With the development of space technology, microwave components with increased power handling capability and reduced weight have been urgently required. In this work, the perforated waveguide technology is proposed to suppress the multipactor effect of high power microwave components. Meanwhile, this novel method has the advantage of reducing components' weight, which makes it to have great potential in space applications. The perforated part of the waveguide components can be seen as an electron absorber (namely, its total electron emission yield is zero) since most of the electrons impacting on this part will go out of the components. Based on thoroughly benchmarked numerical simulation procedures, we simulated an S band and an X band waveguide transformer to conceptually verify this idea. Both electron dynamic simulations and electrical loss simulations demonstrate that the perforation technology can improve the multipactor threshold at least ˜8 dB while maintaining the acceptable insertion loss level compared with its un-perforated components. We also found that the component with larger minimum gap is easier to achieve multipactor suppression. This effect is interpreted by a parallel plate waveguide model. What's more, to improve the multipactor threshold of the X band waveguide transformer with a minimum gap of ˜0.1 mm, we proposed a perforation structure with the slope edge and explained its mechanism. Future study will focus on further optimization of the perforation structure, size, and distribution to maximize the comprehensive performances of microwave components.

Risk factors associated with oroantral perforation during surgical removal of maxillary third molar teeth.

PubMed

Hasegawa, Takumi; Tachibana, Akira; Takeda, Daisuke; Iwata, Eiji; Arimoto, Satomi; Sakakibara, Akiko; Akashi, Masaya; Komori, Takahide

2016-12-01

The relationship between radiographic findings and the occurrence of oroantral perforation is controversial. Few studies have quantitatively analyzed the risk factors contributing to oroantral perforation, and no study has reported multivariate analysis of the relationship(s) between these various factors. This retrospective study aims to fill this void. Various risk factors for oroantral perforation during maxillary third molar extraction were investigated by univariate and multivariate analysis. The proximity of the roots to the maxillary sinus floor (root-sinus [RS] classification) was assessed using panoramic radiography and classified as types 1-5. The relationship between the maxillary second and third molars was classified according to a modified version of the Archer classification. The relative depth of the maxillary third molar in the bone was classified as class A-C, and its angulation relative to the long axis of the second molar was also recorded. Performance of an incision (OR 5.16), mesioangular tooth angulation (OR 6.05), and type 3 RS classification (i.e., significant superimposition of the roots of all posterior maxillary teeth with the sinus floor; OR 10.18) were all identified as risk factors with significant association to an outcome of oroantral perforation. To our knowledge, this is the first multivariate analysis of the risk factors for oroantral perforation during surgical extraction of the maxillary third molar. This RS classification may offer a new predictive parameter for estimating the risk of oroantral perforation.

Primary Report of Totally Tubeless Percutaneous Nephrolithotomy Despite Pelvi-calyceal Perforations.

PubMed

Aghamir, Seyed Mohammad Kazem; Salavati, Alborz; Hamidi, Morteza; FallahNejad, Asghar

2017-07-02

Nephrostomy tube insertion and/or a ureteral stent placement is advised when pelvi-calyceal perforations are encountered during percutaneous nephrolithotomy (PNL) nevertheless totally tubeless PNL is a possible exit strategy in percutaneous renal surgery therefore case series on the short term clinical outcomes of noninvasive management of iatrogenic pelvicalyceal perforations encountered during PNL is presented. During retrospective analysis of 1271 PNL procedures, 25 incidents of accidental ureteral catheter/ jj stent dislodgement during first 24 post-operative hours were identified in patient who had pelvi calyceal perforations and had no nephrostomy tube (tubeless). Thirteen patients could not be re-stented nor a nephrostomytube could have been placed for them mainly due to patient refusal or comorbid conditions. The main outcome was rate of successful noninvasive management. Eighteen Patients bearing mucosal tears (grade I trauma) or visible peri-pelvic fat (grade II) successfully recovered without need for ureteral stenting or nephrostomy (72.0%). In seven (28.0%) cases of extension of the perforation into the peri-pelvic fat (grade III), either nephrostomy insertion or JJ stenting was needed for resolution of fever and urinoma. The major limitation was the necessity to exclude patients and manage them in the standard fashion according to clinical guidelines. Iatrogenic perforations of the collecting system are quite diverse in terms of severity that result in different natural histories and not all might need urinary diversion via nephrostomy or ureteral stenting.Low grade perforations may be successfully managed in totally tubeless fashion nevertheless further prospective investigations seem warranted.

Therapeutic management of perforated gastro-duodenal ulcer: literature review.

PubMed

Mouly, C; Chati, R; Scotté, M; Regimbeau, J-M

2013-11-01

Management of perforated gastro-duodenal ulcer (GDU) is not consensual, from no operative treatment to surgery by simple closure, gastrectomy and vagotomy. The purpose of this study is to report results of the literature concerning management of perforated GDU. Two authors, identified in the databases Pubmed and Embase studies, related to the therapeutic management of perforated GDU. The data were extracted from articles published between 1940 and 2012. Non-operative treatment is feasible for patients in good general condition and in good local circumstances without evolved peritonitis with a success rate more than 50%. Simple closure is the standard method. Laparoscopy is a safe and feasible method for patient with delay of treatment less than 24 hours and without associated complications with a success (meaning non conversion) of 80% and a mortality less than 1%. Rate of conversion is 7.9%, and increases in case of ulcer size >6 mm, frail ulcer edges, bleeding associated, unusual location and septic shock. Helicobacter pylori eradication is essential. Gastric tube, abdominal irrigation and drainage are still debated. Two-stage treatment for perforated gastric carcinoma, which represents 10 to 16% of gastric perforation, is a good option for frail patients with resectable tumors. Management of perforated GDU is still a subject of debate without guidelines but with several possibilities of treatment depending of local circumstances of peritonitis and size of defect >20 mm, general conditions, surgeon patterns and experience. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Effect of packaging conditions on the growth of micro-organisms and the quality characteristics of fresh mushrooms (Agaricus bisporus) stored at inadequate temperatures.

PubMed

González-Fandos, E; Giménez, M; Olarte, C; Sanz, S; Simón, A

2000-10-01

Mushrooms were packed in two polymeric films (perforated and non-perforated PVC) and stored at 17 degrees C and 25 degrees C. The carbon dioxide and oxygen content inside the packages, aerobic mesophiles, Pseudomonas spp., faecal coliforms, Escherichia coli, anaerobic spores and major sensory factors (colour, texture, development stage and presence of moulds) were determined. The non-perforated packages had the highest contents of CO2 (6-7%), the lowest contents of O2 (0.013-0.17%) and the most desirable quality parameters (texture, development stage and absence of moulds). Pseudomonas spp. counts were around 1 logarithmic unit lower in mushrooms packaged in non-perforated film as the O2 concentrations were lower than in perforated film. The mushrooms themselves were inoculated with an enterotoxin A-producing strain of Staphylococcus aureus, packaged in overwrapped trays and stored at 17 and 25 degrees C. Staphylococcus aureus did not grow in the samples stored at 17 degrees C. Only slight growth was observed in mushrooms packaged with non-perforated film after 1 day at 25 degrees C. No enterotoxin was detected in any package. Faecal coliform counts were <2 log cfu g(-1). Escherichia coli was not isolated in any of the samples. At 25 degrees C, counts of anaerobic spores of around 2 log cfu g(-1) were detected in those mushrooms packaged in non-perforated film.

Malignant lymphoma incidentally diagnosed due to the perforation of the small intestine caused by a fish bone: A case report.

PubMed

Hiraki, Masatsugu; Miyoshi, Atsushi; Anegawa, Go; Kubo, Hiroshi; Ikeda, Osamu; Ohira, Keiichi; Azama, Shinya; Kido, Shinichi; Mori, Daisuke; Aibe, Hitoshi; Tanaka, Toshiya; Kitahara, Kenji; Sato, Seiji

2017-01-01

The ingestion of a foreign body is relatively common. However, it rarely results in the perforation of gastrointestinal tract. We herein report an unusual case of malignant lymphoma incidentally diagnosed after the perforation of the small intestine by a fish bone. A 90-year-old woman was admitted to our hospital because of abdominal pain and vomiting. Abdominal computed tomography demonstrated free air and ascites in the abdominal cavity. In the pelvic cavity, a radiopaque linear shadow about 35mm in diameter was shown in the small intestine, and the stricture was exposed to the abdominal cavity. Therefore, a diagnosis of perforation of the small intestine due to ingestion of a foreign body and panperitonitis was made. Emergent laparotomy was performed. The intraoperative findings revealed perforation of the small intestine with a fish bone in the jejunum. Local inflammation at the perforation site was seen, and circulated wall thickness was observed at the distal side of the jejunum. Partial resection of the jejunum and anastomosis of jejuno-jejunostomy was performed. A pathological examination and immunohistochemical study of the resected specimen resulted in a diagnosis of malignant lymphoma of follicular lymphoma Grade 1. It is very difficult to identify the existence malignancy accompanied with gastrointestinal perforation with ingestion of a foreign body. In cases suspected of involving malignancy, careful observation during surgery is needed in order to avoid missing the accompanying malignancy. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Cause rare d'une perforation de la cloison nasale

PubMed Central

Jahidi, Ali; Hemmaoui, Bouchaïb; Itoua, Wulfran Rosaire; Errami, Noureddine; Benariba, Fouad

2014-01-01

Les perforations de la cloison nasale constituent une pathologie fréquente en ORL. Leurs causes sont multiples et restent dominées par les traumatismes chirurgicaux. Les étiologies infectieuses et notamment la tuberculose sont rares. Nous présentons le cas d'une patiente ayant bénéficié d'une méatotomie bilatérale et chez laquelle une perforation de la cloison nasale a été découverte lors d'un examen systématique à un an de son intervention. D'abord considérée comme une complication de la chirurgie, la biopsie des berges de la perforation a permis de déterminer son origine tuberculeuse. La présentation clinique des perforations de la cloison nasale n'est pas spécifique. Elles sont souvent asymptomatiques et de découverte fortuite. Les traumatismes notamment chirurgicaux sont le plus siuvent en cause. L′orogine tuberculeuse resta très rare. Le diagnostic de certitude de tuberculose repose sur la biopsie des berges de cette perforation. Le but de ce travail est de mettre en avant l'intérêt de la biopsie dans le diagnostic de la tuberculose de la cloison nasale. Cette biopsie doit être systématique même en cas d'antécédents de chirurgie endonasale qui est le plus souvent en cause dans les perforations de la cloison nasale. PMID:24932334

High throughput wafer defect monitor for integrated metrology applications in photolithography

NASA Astrophysics Data System (ADS)

Rao, Nagaraja; Kinney, Patrick; Gupta, Anand

2008-03-01

The traditional approach to semiconductor wafer inspection is based on the use of stand-alone metrology tools, which while highly sensitive, are large, expensive and slow, requiring inspection to be performed off-line and on a lot sampling basis. Due to the long cycle times and sparse sampling, the current wafer inspection approach is not suited to rapid detection of process excursions that affect yield. The semiconductor industry is gradually moving towards deploying integrated metrology tools for real-time "monitoring" of product wafers during the manufacturing process. Integrated metrology aims to provide end-users with rapid feedback of problems during the manufacturing process, and the benefit of increased yield, and reduced rework and scrap. The approach of monitoring 100% of the wafers being processed requires some trade-off in sensitivity compared to traditional standalone metrology tools, but not by much. This paper describes a compact, low-cost wafer defect monitor suitable for integrated metrology applications and capable of detecting submicron defects on semiconductor wafers at an inspection rate of about 10 seconds per wafer (or 360 wafers per hour). The wafer monitor uses a whole wafer imaging approach to detect defects on both un-patterned and patterned wafers. Laboratory tests with a prototype system have demonstrated sensitivity down to 0.3 µm on un-patterned wafers and down to 1 µm on patterned wafers, at inspection rates of 10 seconds per wafer. An ideal application for this technology is preventing photolithography defects such as "hot spots" by implementing a wafer backside monitoring step prior to exposing wafers in the lithography step.

A Compact Operational Amplifier with Load-Insensitive Stability Compensation for High-Precision Transducer Interface

PubMed Central

Yang, Xi

2018-01-01

High-resolution electronic interface circuits for transducers with nonlinear capacitive impedance need an operational amplifier, which is stable for a wide range of load capacitance. Such operational amplifier in a conventional design requires a large area for compensation capacitors, increasing costs and limiting applications. In order to address this problem, we present a gain-boosted two-stage operational amplifier, whose frequency response compensation capacitor size is insensitive to the load capacitance and also orders of magnitude smaller compared to the conventional Miller-compensation capacitor that often dominates chip area. By exploiting pole-zero cancellation between a gain-boosting stage and the main amplifier stage, the compensation capacitor of the proposed operational amplifier becomes less dependent of load capacitance, so that it can also operate with a wide range of load capacitance. A prototype operational amplifier designed in 0.13-μm complementary metal–oxide–semiconductor (CMOS) with a 400-fF compensation capacitor occupies 900-μm2 chip area and achieves 0.022–2.78-MHz unity gain bandwidth and over 65∘ phase margin with a load capacitance of 0.1–15 nF. The prototype amplifier consumes 7.6 μW from a single 1.0-V supply. For a given compensation capacitor size and a chip area, the prototype design demonstrates the best reported performance trade-off on unity gain bandwidth, maximum stable load capacitance, and power consumption. PMID:29382183

Double gloving to reduce surgical cross-infection.

PubMed

Tanner, J; Parkinson, H

2002-01-01

The invasive nature of surgery, with its increased exposure to blood, means that during surgery there is a high risk of transfer of pathogens. Pathogens can be transferred through contact between surgical patients and the surgical team, resulting in post-operative or blood borne infections in patients or blood borne infections in the surgical team. Both patients and the surgical team need to be protected from this risk. This risk can be reduced by implementing protective barriers such as wearing surgical gloves. Wearing two pairs of surgical gloves, as opposed to one pair, is considered to provide an additional barrier and further reduce the risk of contamination. The primary objective of this review was to determine if double gloving (wearing two pairs of gloves), rather than single gloving, reduces the number of post-operative or blood borne infections in surgical patients or blood borne infections in the surgical team. The secondary objective of this review was to determine if double gloving, rather than single gloving, reduces the number of perforations to the innermost pair of surgical gloves. The innermost gloves (next to skin) compared with the outermost gloves are considered to be the last barrier between the patient and the surgical team. The reviewers searched the Cochrane Wounds Group Specialised Trials Register, MEDLINE, CINAHL, EMBASE and the Cochrane Controlled Trials Register. Glove manufacturing companies and professional organisations were also contacted. Randomised controlled trials involving: single gloving, double gloving, glove liners or coloured puncture indicator systems. Both reviewers independently assessed the relevance and quality of each trial. Trials to be included were cross checked and authenticated by both reviewers. Data was extracted by one reviewer and cross checked for accuracy by the second reviewer. Two trials were found which addressed the primary outcome. A total of 18 randomised controlled trials which measured glove perforations were identified and included in the review. DOUBLE GLOVING (wearing two pairs of latex gloves). Nine trials compared single latex gloves versus double latex gloves. These found no difference in the number of perforations between the single latex gloves and the outermost pair of the double latex gloves, but the number of perforations to the double latex-innermost glove was significantly reduced when two pairs of latex gloves were worn. ORTHOPAEDIC GLOVES (thicker than standard latex gloves). One trial compared single latex orthopaedic gloves with double latex gloves. This showed there was no difference in the number of perforations to the innermost gloves when wearing double latex gloves compared with a single pair of latex orthopaedic gloves. INDICATOR GLOVES (coloured latex gloves worn underneath latex gloves). Three trials compared double latex gloves versus double latex indicator gloves. These trials showed similar numbers of perforations to both the innermost and the outermost gloves for both gloving groups. Perforations to the outermost gloves were detected more easily when double latex indicator gloves were worn. Wearing double latex indicator gloves did not increase the detection of perforations to the innermost gloves. GLOVE LINERS (an insert worn between two pairs of latex gloves). Two trials compared double latex gloves versus double latex gloves with liners. These trials showed a significant reduction in the number of perforations to the innermost glove when a glove liner was worn between two pairs of latex gloves. CLOTH GLOVES (cloth gloves worn on top of latex gloves). Two trials compared double latex gloves versus latex inner with cloth outer gloves. These trials showed that wearing a cloth outer glove significantly reduced the number of perforations to the innermost latex glove. STEEL WEAVE GLOVES (steel weave gloves worn on top of latex gloves). One trial compared double latex gloves versus latex inner with steel weave outer gloves. This trial showed no reduction in the number of perforations to the innermost glove when wearing a steel weave outer glove. Wearing two pairs of latex gloves significantly reduces the number of perforations to the innermost glove. This evidence comes from trials undertaken in 'low risk' surgical specialties, that is specialties which did not include orthopaedic joint surgery. Wearing two pairs of latex gloves does not cause the glove wearer to sustain more perforations to their outermost glove. Wearing double latex indicator gloves enables the glove wearer to detect perforations to the outermost glove more easily than when wearing double latex gloves. However wearing a double latex indicator system will not assist with the detection of perforations to the innermost glove, nor reduce the number of perforations to either the outermost or the innermost glove. Wearing a glove liner between two pairs of latex gloves to undertake joint replacement surgery significantly reduces the number of perforations to the innermost glove compared with double latex gloves only. Wearing cloth outer gloves to undertake joint replacement surgery significantly reduces the number of perforations to the innermost glove compared with wearing double latex gloves. Wearing steel weave outer gloves to undertake joint replacement surgery does not reduce the number of perforations to innermost gloves compared with double latex gloves.

Spontaneous Caecal Perforation Associated with Ogilvie's Syndrome Following Vaginal Delivery - A Case Report.

PubMed

E, Harish; Vk, Sundeep; Kola, Sivasai Krishnaprasad; Kg, Dharma Kumar

2014-06-01

Acute pseudo-obstruction of the large bowel, Ogilvie's syndrome, can occur in the postpartum period following caesarean section which can result in caecal dilatation and may progress to perforation. This is quiet rare following normal vaginal delivery. Only two previous reports have been found in the English literature. We report a case of Ogilvie's syndrome with caecal perforation following normal vaginal delivery.

Subcutaneous Emphysema Mimicking Gas Gangrene Following Perforation of the Rectum: A Case Report

PubMed Central

Moon, Eun-Sun; Jung, Sung-Taek; Seo, Hyoung-Yeon

2004-01-01

We report a case of extensive subcutaneous emphysema of the lower extremity mimicking gas gangrene following perforation of the rectum in a 38-yr-old man. Subcutaneous emphysema of the leg may rarely occur secondary to perforation of the gastrointestinal tract and has often created serious diagnostic problems and high mortality rates. Therefore, prompt diagnosis and aggressive treatment is imperative. PMID:15483358

Deliverable 2.4.4 -- Evaluation and single-well models for the demonstration wells, Class 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deo, Milind; Morgan Craig D.

2000-07-12

Two single-well models were developed for Michelle Ute and Malnar Pike wells. The perforated intervals span thousands of feet in both the wells. Geological properties were calculated for all the perforated beds. The information was used to develop models for these two wells. These were comprehensive models since they took into account all the perforated beds.

Scoping a perforated bleeding peptic ulcer: learning points.

PubMed

Wani, Abdul Majid; Hussain, Waleed Mohd; AlMiamini, Wail; Khoujah, Amer M; Diari, Mohd S; Akhtar, Mubeena; Alharbi, Zeyad S

2011-03-24

Peptic ulcer perforation and haemorrhage is not unusual as a complication of peptic ulcer disease. In the older patientspresentation can be dramatic and atypical. The authors are presenting a case of duodenal ulcer perforation and haemorrhage which was misdiagnosed as a gastric malignancy and thus failure to have Helicobacter pylori eradication, recurrence with complication and hesitancy in surgical intervention due to initial label of malignancy.

Development of the technology for the fabrication of reliable laminar from control panels

NASA Technical Reports Server (NTRS)

Meade, L. E.; Kays, A. O.; Ferrill, R. S.; Young, H. R.

1977-01-01

Materials were assessed and fabrication techniques were developed for use in the manufacture of wing surface materials compatible with the application of both aluminum alloys and nonmetallic composites. The concepts investigated included perforations and slots in the metallic test panels and microporosity and perforations in the composite test panels. Perforations were produced in the metallic test panels by the electron beam process and slots were developed by controlled gaps between the metal sheets. Microporosity was produced in the composite test panels by the resin bleed process, and perforations were produced by the fugitive fiber technique. Each of these concepts was fabricated into test panels, and air flow tests were conducted on the panels.

Cell perforation mediated by plasmonic bubbles generated by a single near infrared femtosecond laser pulse.

PubMed

Boutopoulos, Christos; Bergeron, Eric; Meunier, Michel

2016-01-01

We report on transient membrane perforation of living cancer cells using plasmonic gold nanoparticles (AuNPs) enhanced single near infrared (NIR) femtosecond (fs) laser pulse. Under optimized laser energy fluence, single pulse treatment (τ = 45 fs, λ = 800 nm) resulted in 77% cell perforation efficiency and 90% cell viability. Using dark field and ultrafast imaging, we demonstrated that the generation of submicron bubbles around the AuNPs is the necessary condition for the cell membrane perforation. AuNP clustering increased drastically the bubble generation efficiency, thus enabling an effective laser treatment using low energy dose in the NIR optical therapeutical window. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Successful management of grade III coronary perforation after percutaneous angioplasty in a high-risk patient: a case report.

PubMed

Coloma Araniya, Ricardo; Beas, Renato; Maticorena-Quevedo, Jesús; Anduaga-Beramendi, Alexander; Pastrana Castillo, Marco Antonio

2016-03-03

Coronary perforation is a rare complication in patients undergoing percutaneous coronary angioplasty. The mortality of this complication varies depending on factors related to the patient and the procedure performed, reaching 44% in patients with Ellis type III perforation. We report the case of an 81 year old male with multiple cardiovascular risk factors, who underwent percutaneous angioplasty for unstable angina management. The patient developed grade III coronary perforation in the anterior descending artery, which was successfully managed with balloon inflation to 6 atmospheres for 10 minutes twice in the affected area, with an interval of 5 minutes between each dilatation. The patient improved and was discharged.

Dynamic Analysis of Irradiation of High Intensity Focused Ultrasound (HIFU) to Achieve a Living Tissue Perforation

NASA Astrophysics Data System (ADS)

Mochizuki, Takashi; Kitazumi, Gontaro; Katsuike, Yasumasa; Hotta, Sayo; Maruyama, Hirotaka; Chiba, Toshio

2010-03-01

It is well known that tissue perforation is performed by the shock waves generated by the collapse of micro bubbles due to HIFU irradiation. However, the angle-dependency between the HIFU irradiation beam and the tissue membrane has not been studied in detail so far. The objective of this study was to investigate the HIFU parameters which were the most effective in perforating the tissues with the heart beating, especially the angle dependency of the beam with the observation using high speed video camera. The result shows that the ultrasound beam should be at right angle to the membrane to perforate the tissue membrane effectively.

Videothoracoscopic management of a perforated central vein and pleura after ultrasound-guided internal jugular vein cannulation: a case report

PubMed Central

Kim, Jeong-Eun; Jeon, Joon-Pyo; Kim, Yongsuk; Jeong, Su Ah

2014-01-01

A 23-year-old male underwent a left internal jugular vein catheterization during extended surgery for treatment of multiple fractures due to a traffic accident. Although the catheterization was performed under ultrasound (US) guidance, iatrogenic perforation of the central vein and pleura occurred. The catheter was removed, and the perforated site was addressed under thoracoscopy rather than an open thoracotomy. This case suggests that using US does not completely guarantee a complication-free outcome, and that catheter placement should be carefully confirmed. In addition, this case suggests that thoracoscopy may be an ideal method of resolving a perforation of the central vein and pleura. PMID:24851167

Esophageal Perforation After Transesophageal Echocardiogram.

PubMed

Shapira, Michael Y.; Hirshberg, Boaz; Agid, Ronit; Zuckerman, Elena; Caraco, Yoseph

1999-02-01

Esophageal rupture after transesophageal echocardiogram (TEE) is a rare but life-threatening complication. Risk factors for perforation include spasm or hypertrophy of the cricopharyngeal sphincter, cervical arthritis, forward and left lateral bending of the distal esophagus, and esophageal disease such as inflammation or neoplasm. We present the case of a 80-year-old woman who developed perforation of her esophagus after TEE. Prior irradiation to the chest due to treatment for breast cancer and subsequent fibrosis probably contributed to this complication. Physicians referring patients for a TEE and physicians performing this procedure should be aware for the risk of perforation. The identification of risk factors and gentle maneuvering of the probe may prevent this severe, life-threatening complication.

Recurrent gastric perforation as a late complication of radiotherapy for mucosa-associated lymphoid tissue lymphoma of the stomach.

PubMed

Otsuka, Taiga; Noda, Takahiro; Yokoo, Masako; Ibaraki, Kazuo

2008-01-01

Radiation therapy can be used to treat Helicobacter pylori-negative or eradication-refractory extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) of the stomach. We report a case of gastric perforation which occurred more than 1 year after the completion of radiotherapy for H. pylori eradication-refractory gastric MALT lymphoma, and then recurred shortly afterwards. This was considered to be a late complication of radiation toxicity. Although gastric perforation due to radiotherapy has been reported very rarely in the past, even in advanced disease, this case shows that perforation can develop in patients with superficial disease and can relapse.

Two cases of corneal perforation after oral administration of nonsteroidal anti-inflammatory drugs: oral NSAID-induced corneal damage.

PubMed

Masuda, Ikuya; Matsuo, Toshihiko; Okamoto, Kazuo; Matsushita, Kyoko; Ohtsuki, Hiroshi

2010-01-01

To report 2 cases of corneal perforation associated with the use of oral nonsteroidal anti-inflammatory drugs (NSAIDs). In a 62-year-old woman and a 79-year-old woman, corneal perforation occurred after 7 days and 5 months of oral NSAIDs administration, respectively. After NSAIDs were discontinued, the cornea epithelialized and the anterior chamber formed within 14 and 10 days, respectively. It is well known that topical NSAIDs cause corneal perforation. Observations in the present cases suggest that the oral administration of NSAIDs may also cause corneal damage, and hence, medical professionals should consider the risk of damage to the cornea when administering these drugs orally.

The Clinical Importance of Perforator Preservation in Intracranial Aneurysm Surgery: An Overview with a Review of the Literature.

PubMed

Joo, Sung-Pil; Kim, Tae-Sun

2017-01-01

Clipping for intracranial aneurysms is done to achieve complete occlusion of the aneurysm without a remnant sac. Despite modern advancements of neurosurgical techniques, morbidity related to the clipping of intracranial aneurysms still exists. Clip occlusion of a parent artery or small hidden perforators commonly leads to permanent neurological deficits, and is a serious and unwanted complication. Thus, preserving blood flow in the branches and perforators of a parent artery is very important for successful surgery without postoperative morbidity and mortality. The aim of this review article is to discuss the consequences of perforator injury and how to avoid this phenomenon in aneurysm surgeries using intraoperative monitoring devices.

[Conversion Therapy of Initially Unresectable Rectal Cancer with Perforation via FOLFOX4 Chemotherapy].

PubMed

Yamada, Chizu; Ishikawa, Fumihiko; Nitta, Hiroshi; Fujita, Yoshihisa; Omoto, Hideyuki; Kamata, Shigeyuki; Ito, Hiroshi

2015-11-01

We describe a case of perforated rectal cancer that became curatively resectable after FOLFOX4 chemotherapy. An 81- year-old woman was transferred to our hospital with a diagnosis of bowel perforation. She underwent emergency transverse colostomy, peritoneal lavage, and the insertion of indwelling drainage tubes, because the perforated rectal cancer was considered unresectable. After recuperation, she received chemotherapy consisting of FOLFOX4 and bevacizumab. Owing to a good response to the treatment after 4 months, rectal resection was achieved curatively. Wound dehiscence occurred as a postoperative complication. The patient chose not to receive adjuvant chemotherapy. Currently, she has been alive for more than 1 year 3 months after resection without recurrence.

Heat transfer and flow friction correlations for perforated plate matrix heat exchangers

NASA Astrophysics Data System (ADS)

Ratna Raju, L.; Kumar, S. Sunil; Chowdhury, K.; Nandi, T. K.

2017-02-01

Perforated plate matrix heat exchangers (MHE) are constructed of high conductivity perforated plates stacked alternately with low conductivity spacers. They are being increasingly used in many cryogenic applications including Claude cycle or Reversed Brayton cycle cryo-refrigerators and liquefiers. Design of high NTU (number of (heat) transfer unit) cryogenic MHEs requires accurate heat transfer coefficient and flow friction factor. Thermo-hydraulic behaviour of perforated plates strongly depends on the geometrical parameters. Existing correlations, however, are mostly expressed as functions of Reynolds number only. This causes, for a given configuration, significant variations in coefficients from one correlation to the other. In this paper we present heat transfer and flow friction correlations as functions of all geometrical and other controlling variables. A FluentTM based numerical model has been developed for heat transfer and pressure drop studies over a stack of alternately arranged perforated plates and spacers. The model is validated with the data from literature. Generalized correlations are obtained through regression analysis over a large number of computed data.

Management of nasal septal perforation using silicone nasal septal button

PubMed Central

Mullace, M; Gorini, E; Sbrocca, M; Artesi, L; Mevio, N

2006-01-01

Summary Nasal septal perforation may present with various symptoms: epistaxis, crusting, secondary infection, whistling and nasal obstruction. Perforation may be treated by conservative pharmacological treatment or closed by surgical approach. A useful alternative is mechanical obturation, achieved inserting a prosthesis. The present report refers to a study on 15 patients (10 male, 5 female, mean age 38.5 years) treated by insertion of a one-piece or two-piece silicone septal button (Xomed). In the follow-up period, insertion of the nasal button reduced epistaxis, eliminated whistling during inspiration, and reduced nasal obstruction and crusting around the margin of the perforation. Contraindications are presence of acute infection with osteitis, chronic septal disease (Wegener), neoplasia and extremely large perforations. The latest buttons appear to be superior to the conventional type on account of plasticity and adaptability which offer greater conformity to the septum. This study also reveals that the new septal button is well tolerated by patients. PMID:18236638

Experimental investigation of sound absorption properties of perforated date palm fibers panel

NASA Astrophysics Data System (ADS)

Elwaleed, A. K.; Nikabdullah, N.; Nor, M. J. M.; Tahir, M. F. M.; Zulkifli, R.

2013-06-01

This paper presents the sound absorption properties of a natural waste of date palm fiber perforated panel. A single layer of the date palm fibers was tested in this study for its sound absorption properties. The experimental measurements were carried out using impedance tube at the acoustic lab, Faculty of Engineering, Universiti Kebangsaan Malaysia. The experiment was conducted for the panel without air gap, with air gap and with perforated plate facing. Three air gap thicknesses of 10 mm, 20 mm and 30 mm were used between the date palm fiber sample and the rigid backing of the impedance tube. The results showed that when facing the palm date fiber sample with perforated plate the sound absorption coefficient improved at the higher and lower frequency ranges. This increase in sound absorption coincided with reduction in medium frequency absorption. However, this could be improved by using different densities or perforated plate with the date palm fiber panel.

Laparoscopic management of duodenal ulcer perforation: is it advantageous?

PubMed

Palanivelu, C; Jani, Kalpesh; Senthilnathan, P

2007-01-01

Surgery is the mainstay of treatment of patients with peptic duodenal perforation. With the advent of minimal access techniques, laparoscopy is being used for the treatment of this condition. Retrospective analysis of 120 consecutive patients (mean age 44.5 years; 111 men) with duodenal ulcer perforation who had undergone laparoscopic surgery. 87 patients had history of tobacco consumption, 12 were chronic NSAID users, 72 had Helicobacter pylori infection and 36 had a co-morbid condition. The mean time to surgery from onset of symptoms was 28.4 hours. The median operating time was 46 minutes. All patients underwent laparoscopic closure of the perforation with Graham's patch omentopexy; 12 patients underwent additional definitive ulcer surgery. The morbidity rate was 7.5%; no patient needed conversion to open surgery or died. The mean postoperative hospital stay was 5.8 days. Results of laparoscopic management of perforated peptic ulcer are encouraging, with no conversion to open surgery, low morbidity and no mortality.

Oblique Wave-Induced Responses of A VLFS Edged with A Pair of Inclined Perforated Plates

NASA Astrophysics Data System (ADS)

Cheng, Yong; Ji, Chun-yan; Zhai, Gang-jun; Oleg, Gaidai

2018-03-01

This paper is concerned with the hydroelastic responses of a mat-like, rectangular very large floating structure (VLFS) edged with a pair of horizontal/inclined perforated anti-motion plates in the context of the direct coupling method. The updated Lagrangian formulae are applied to establish the equilibrium equations of the VLFS and the total potential formula is employed for fluids in the numerical model including the viscous effect of the perforated plates through the Darcy's law. The hybrid finite element-boundary element (FE-BE) method is implemented to determine the response reduction of VLFS with attached perforated plates under various oblique incident waves. Also, the numerical solutions are validated against a series of experimental tests. The effectiveness of the attached perforated plates in reducing the deflections of the VLFS can be significantly improved by selecting the proper design parameters such as the porous parameter, submergence depth, plate width and inclination angle for the given sea conditions.

Real scale experimental study for performance evaluation of unidirectional air diffuser perforated panels

NASA Astrophysics Data System (ADS)

Tăcutu, Laurenţiu; Nastase, Ilinca; Iordache, Vlad; Catalina, Tiberiu; Croitoru, Cristiana Verona

2018-02-01

Nowadays, there is an increasing emphasis on indoor air quality due to technological evolution and the fact that people spend most of the time in enclosed spaces. Also, energy efficiency is another related factor that gains more and more attention. Improving air distribution in an enclosure can lead to achieve these goals. This improvement can be done by adjustingthe air terminals position, theredimensions or the air diffuser perforations. The paper presents the study of 8 types of panels with different perforations shapes. The systems were characterized by flow, pressure loss and noise. Usualand special geometries were chosen, all having the same flowsurface. The perforated panels were mounted in a unidirectional air flow (UAF)diffuser, also called a laminar air flow (LAF)diffuser, that is placed in a real scale operating room (OR) in our laboratory.The purpose of this study is to determine whether changing the shape in the perforated panels can improve the technical parameters of the diffuser.

[Meta-analysis of laparoscopic and open repair of perforated peptic ulcer].

PubMed

Ding, Jie; Liao, Guo-qing; Zhang, Zhong-min; Pan, Yang; Li, Dong-miao; Wang, Run-hua; Xu, Kai-sheng; Yang, Xiao-fei; Yuan, Ping; Wang, Shao-yong

2011-10-01

To assess the safety and feasibility of laparoscopic and open repair of perforated peptic ulcer. Studies on comparison between laparoscopic repair(LR) and open repair(OR) of perforated peptic ulcer were collected. Data of operating time, blood loss, time to first flatus, postoperative hospital stay, postoperative complications and mortality between LR group and OR group were meta-analyzed using fixed effect model and random effect model. Nineteen studies including 1507 patients were selected for this study,including laparoscopic surgery(n=673) and open surgery(n=834). There were significant differences in blood loss, time to first flatus, postoperative hospital stay, wound infection rate and mortality between LR group and OR group. However, no significant differences existed in operative time, postoperative sepsis, pulmonary infection, abdominal abscess, and suture leakage between the two groups. Laparoscopic repair of perforated peptic ulcer is associated with improved outcomes in terms of less blood loss, quicker recovery, and lower rates of wound infection and mortality. Laparoscopic repair of perforated peptic ulcer is safe and feasible.

Perforated peptic ulcer associated with abdominal compartment syndrome.

PubMed

Lynn, Jiun-Jen; Weng, Yi-Ming; Weng, Chia-Sui

2008-11-01

Abdominal compartment syndrome (ACS) is defined as an increased intra-abdominal pressure with adverse physiologic consequences. Abdominal compartment syndrome caused by perforated peptic ulcer is rare owing to early diagnosis and management. Delayed recognition of perforated peptic ulcer with pneumoperitoneum, bowel distension, and decreased abdominal wall compliance can make up a vicious circle and lead to ACS. We report a case of perforated peptic ulcer associated with ACS. A 74-year-old man with old stroke and dementia history was found to have distended abdomen, edema of bilateral legs, and cyanosis. Laboratory tests revealed deterioration of liver and kidney function. Abdominal compartment syndrome was suspected, and image study was arranged to find the cause. The study showed pneumoperitoneum, contrast stasis in heart with decreased caliber of vessels below the abdominal aortic level, and diffuse lymphedema at the abdominal walls. Emergent laparotomy was performed. Perforated peptic ulcer was noted and the gastrorrhaphy was done. The symptoms, and liver and kidney function improved right after emergent operation.

Harvesting solar energy by means of charge-separating nanocrystals and their solids.

PubMed

Diederich, Geoffrey; O'Connor, Timothy; Moroz, Pavel; Kinder, Erich; Kohn, Elena; Perera, Dimuthu; Lorek, Ryan; Lambright, Scott; Imboden, Martene; Zamkov, Mikhail

2012-08-23

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials offering a superior control over the spatial distribution of charge carriers across material interfaces. As this study demonstrates, a combination of donor-acceptor nanocrystal (NC) domains in a single nanoparticle can lead to the realization of efficient photocatalytic materials, while a layered assembly of donor- and acceptor-like nanocrystals films gives rise to photovoltaic materials. Initially the paper focuses on the synthesis of composite inorganic nanocrystals, comprising linearly stacked ZnSe, CdS, and Pt domains, which jointly promote photoinduced charge separation. These structures are used in aqueous solutions for the photocatalysis of water under solar radiation, resulting in the production of H2 gas. To enhance the photoinduced separation of charges, a nanorod morphology with a linear gradient originating from an intrinsic electric field is used. The inter-domain energetics are then optimized to drive photogenerated electrons toward the Pt catalytic site while expelling the holes to the surface of ZnSe domains for sacrificial regeneration (via methanol). Here we show that the only efficient way to produce hydrogen is to use electron-donating ligands to passivate the surface states by tuning the energy level alignment at the semiconductor-ligand interface. Stable and efficient reduction of water is allowed by these ligands due to the fact that they fill vacancies in the valence band of the semiconductor domain, preventing energetic holes from degrading it. Specifically, we show that the energy of the hole is transferred to the ligand moiety, leaving the semiconductor domain functional. This enables us to return the entire nanocrystal-ligand system to a functional state, when the ligands are degraded, by simply adding fresh ligands to the system. To promote a photovoltaic charge separation, we use a composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells.

[Esophageal perforation and mediastinitis caused by fishbone ingestion: report of 3 cases].

PubMed

Vásquez, Julio C; Montesinos, Efraín; Castillo, Luis; Rojas, Luis; Peralta, Julio

2006-01-01

We present 3 consecutive cases of fishbone perforation of the esophagus that resulted in acute mediastinitis. All patients were successfully managed with drainage and debridement of the mediastinum and pleural cavity. However, temporary exclusion with external ligation of the esophagus was also performed in one patient, with spontaneous recanalization two weeks later. We discuss the possible role of this surgical maneuver in the management of esophageal perforation.

Application of a new laser Doppler imaging system in planning and monitoring of surgical flaps

NASA Astrophysics Data System (ADS)

Schlosser, Stefan; Wirth, Raphael; Plock, Jan A.; Serov, Alexandre; Banic, Andrej; Erni, Dominique

2010-05-01

There is a demand for technologies able to assess the perfusion of surgical flaps quantitatively and reliably to avoid ischemic complications. The aim of this study is to test a new high-speed high-definition laser Doppler imaging (LDI) system (FluxEXPLORER, Microvascular Imaging, Lausanne, Switzerland) in terms of preoperative mapping of the vascular supply (perforator vessels) and postoperative flow monitoring. The FluxEXPLORER performs perfusion mapping of an area 9×9 cm with a resolution of 256×256 pixels within 6 s in high-definition imaging mode. The sensitivity and predictability to localize perforators is expressed by the coincidence of preoperatively assessed LDI high flow spots with intraoperatively verified perforators in nine patients. 18 free flaps are monitored before, during, and after total ischemia. 63% of all verified perforators correspond to a high flow spot, and 38% of all high flow spots correspond to a verified perforator (positive predictive value). All perfused flaps reveal a value of above 221 perfusion units (PUs), and all values obtained in the ischemic flaps are beneath 187 PU. In summary, we conclude that the present LDI system can serve as a reliable, fast, and easy-to-handle tool to detect ischemia in free flaps, whereas perforator vessels cannot be detected appropriately.