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Useful Technique (useful + technique)
Selected AbstractsGaleal Hinge Flaps: A Useful Technique for Immediate Repair of Scalp Defects Extending to PeriosteumDERMATOLOGIC SURGERY, Issue 1 2009MATTHEW HALPERN MD First page of article [source] Spark Plasma Sintering as a Useful Technique to the Nanostructuration of Piezo-Ferroelectric Materials,ADVANCED ENGINEERING MATERIALS, Issue 8 2009Teresa Hungría Abstract This review gathers detail on the processing of piezo-ferroelectric ceramic materials by spark plasma sintering for the first time. The results reported here clearly indicate that it is a powerful technique and opens the possibility of processing ceramics with controlled sub-micron or even nanoscale grain sizes. [source] Multislice Computed Tomography of the First Rib: A Useful Technique for Bone Age AssessmentJOURNAL OF FORENSIC SCIENCES, Issue 4 2010Guillaume Moskovitch M.S. Abstract:, Macroscopic study of the first rib has been described by Kunos et al. as an efficient method of age estimation. We retrospectively reviewed a test sample of 160 first right ribs obtained from multislice computed tomography (MSCT) clinical investigations of living individuals aged 15,30 years old. Based on the descriptions of Kunos et al., we analyzed the morphological appearance of the sternal end of the first rib on two- and three-dimensional MSCT reconstructions and defined changes in appearance in stages (from 2 to 5). We also studied the calcification and ossification of the costal cartilage as an independent feature. By statistical analysis (ANOVA), we determined for each gender the correlation between the estimated stage of the costal face, the appearance of the costal cartilage, and the documented age of the subjects. We demonstrated that MSCT of the first rib appears to be an efficient noninvasive modality for bone age estimation. [source] Rapid Atrial Pacing: A Useful Technique During Slow Pathway AblationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2007LEONARDO LIBERMAN M.D. Background: Catheter ablation is the treatment of choice for atrioventricular nodal reentrant tachycardia (AVNRT) with a success rate of 95,98%. The appearance of junctional rhythm during radiofrequency (RF) application to the slow pathway has been consistently reported as a marker for the successful ablation of AVNRT. Ventriculoatrial (VA) conduction during junctional rhythm has been used by many as a surrogate marker of antegrade atrioventricular nodal (AVN) function. However, VA conduction may not be an accurate or consistent marker for antegrade AVN function and reliance on this marker may leave some patients at risk for antegrade AVN injury. Objective: The purpose of this study is to describe a technique to ensure normal antegrade AVN function during junctional rhythm at the time of RF catheter ablation of the slow pathway. Methods: Retrospective review of all patients less than 21 years old who underwent RF ablation for AVNRT at our institution from January 2002 to July 2005. During RF applications, immediately after junctional rhythm was demonstrated, RAP was performed to ensure normal antegrade AVN function. Postablation testing was performed to assess AVN function and tachycardia inducibility. Results: Fifty-eight patients underwent RF ablation of AVNRT during the study period. The mean age ± SD was 14 ± 3 years (range: 5,20 years). The weight was 53 ± 15 Kg (range: 19,89 Kg). The preablation Wenckebach cycle length was 397 ± 99 msec (range: 260,700 msec). Fifty-four patients had inducible typical AVNRT, and four patients had atypical tachycardia. The mean tachycardia cycle length ± SD was 323 ± 62 msec (range: 200,500 msec). Patients underwent of 8 ± 7 total RF applications (median: 7; range 1 to 34), for a total duration of 123 ± 118 seconds (median: 78 sec, range: 20,473 sec). Junctional tachycardia was observed in 52 of 54 patients. RAP was initiated during junctional rhythm in all patients. No patient developed any degree of transient or permanent AVN block. Following ablation, the Wenckebach cycle length decreased to 364 ± 65 msec (P < 0.01). Acutely successful RF catheter ablation was obtained in 56 of 58 patients (96%). Conclusion: Rapid atrial pacing during radiofrequency catheter ablation of the slow pathway is a safe alternative approach to ensure normal AVN function. [source] Videoanoscopy: Useful technique in the evaluation of hemorrhoidsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 8pt2 2008Kareem Harish Abstract Background and Aim:, Rigid proctoscopy, the gold standard for detecting hemorrhoids, has become a neglected procedure in the era of flexible endoscopy. Evaluation of hemorrhoids is often done with the retroflexed fiberoptic colonoscope. The aim of this study was to evaluate the technique of videoanoscopy in comparison with retroflexion of colonoscope in the rectum to detect hemorrhoids and to correlate objective findings of hemorrhoids and their relation to bleeding. Methods:, In total, 544 patients were screened and 358 patients were evaluated by the technique of videoanoscopy and retroflexion of colonoscope in the rectum. The video images of both the procedures were independently analyzed by two observers for the presence or absence of hemorrhoids. The videoanoscopy images were also analyzed for number of columns of hemorrhoids, size and presence of red-color sign. Results:, Videoanoscopy detected hemorrhoids in a significantly higher number of subjects when compared with retroflexion of colonoscope in the rectum by both observers (P < 0.05). The average kappa value was 0.637 and 0.779 for retroflexed colonoscopy and videoanoscopy, respectively. Red-color sign was present in 80.5% of patients with bleeding compared with only 30.3% in the non-bleeding group. The majority (71%) of patients in the bleeding group had larger hemorrhoids. Red-color sign and size of hemorrhoidal columns correlated with bleeding (P < 0.05). Conclusion:, Videoanoscopy is a simple technique with increased sensitivity to detect hemorrhoids compared with intrarectal retroflexion of colonoscope and yields valuable objective information about the presence and condition of hemorrhoids. It should be performed as an extension of standard colonoscopy. [source] Extrasphincteric rectal fistulas treated successfully by Soave's procedure despite marked local sepsisBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 2 2003C. A. Maxwell-Armstrong Useful technique in pelvic sepsis [source] The Optimization of Signal Settings on a Signalized Roundabout Using the Cross-entropy MethodCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 2 2008Mike Maher It is an iterative process that consists of generating solutions from some probability distribution whose parameter values are updated in each iteration using information from the best solutions found in that iteration. The article applies the method to the problem of the optimization of signal settings on a signalized roundabout. The performance of any given set of timings is evaluated using the cell transmission model, a deterministic macroscopic traffic flow model that permits the modeling of the spatial extent of queues and the possibility of "blocking back." The results from the investigations are encouraging, and show that the CEM has the potential to be a useful technique for tackling global optimization problems. [source] Repair of a Large Wound of the Back, Post-Mohs Micrographical Excision, Using Chronic Skin ExpansionDERMATOLOGIC SURGERY, Issue 6 2003Ron M. Shelton MD Background. Large defects not otherwise closed primarily may be closed after chronic skin expansion. Objective. If chronic expansion were deemed indicated for the closure of a proposed defect expected to result from Mohs micrographic surgery, can it be performed before Mohs surgery, avoiding the increased chance of expander extrusion via the defect when done postoperatively? Methods. A team approach of a Mohs surgeon and a plastic surgeon coordinated scheduling an insertion of and staged infiltration of a tissue expander before Mohs surgical removal of a large basal cell carcinoma on the back of a young woman. The reconstruction after Mohs surgery was scheduled for the immediate postoperative period. Results. The Mohs surgery completed removed the carcinoma, and the expander was removed, enabling the surgeon to perform a side-to-side closure. Conclusion. Provided that there is not a great probability of the neoplasm extending significantly deeper or wider than expected and that the skin expander is placed so as not to disturb the plane of Mohs excision, this is a useful technique to close large Mohs defects. [source] Polymicrobial lung infection in postrenal transplant recipient diagnosed by fine-needle aspiration cytologyDIAGNOSTIC CYTOPATHOLOGY, Issue 4 2010Rajan Duggal M.D. Abstract Tuberculous and fungal infections are among the non-neoplastic lesions of the lung, in which fine-needle aspiration cytology (FNAC) has proven to be a useful technique in both immunocompromised and immunocompetent patients. The presence of polymicrobial infection in a renal transplant recipient is documented in the literature, but has rarely been diagnosed on cytology. We report a case of concomitant pulmonary cryptococcosis, aspergillosis, and tuberculosis in a renal transplant recipient diagnosed on FNAC. A 50-year-old renal transplant recipient, asymptomatic for 3 year, presented with intermittent low-grade fever associated with cough, expectoration, and a newly developed cavitatory lesion in the left lung on chest X-ray. Computed tomography-guided FNAC performed on the lung lesion showed fungal profiles with septate hyphae and acute-angled branching consistent with morphology of Aspergillus. In addition, numerous yeast forms of cryptococcus and a few acid-fast mycobacterial tubercle bacilli were seen. Guided FNAC is a useful and reliable technique for the diagnosis of pulmonary infection. One should always keep in mind the possibility of polymicrobial infections especially inimmunocompromised patients. Diagn. Cytopathol. 2010. © 2009 Wiley-Liss, Inc. [source] Unsuspected systemic amyloidosis diagnosed by fine-needle aspiration of the salivary gland: Case reportDIAGNOSTIC CYTOPATHOLOGY, Issue 1 2004Ph.D., Tamar Giorgadze M.D. Abstract Amyloidosis of the head and neck region may represent a local amyloidoma or a manifestation of systemic disease. Involvement of major salivary glands by either primary or secondary forms of amyloidosis is very rare. We describe a case of systemic amyloidosis that initially presented as submandibular gland mass and was diagnosed by fine-needle aspiration (FNA). A 69-year-old male presented with submandibular mass. His past medical history was significant for left forearm melanoma that was excised 6 years ago and tricuspid valve endocarditis after valvular replacement 3 months prior to FNA of the submandibular gland. The patient had no symptoms or clinical and laboratory data suggestive of amyloidosis. FNA specimen showed salivary gland tissue and abundant amorphous material, which stained positive for amyloid with Congo red stain and showed typical birefringence when examined by polarized microscopy. Further workup of the patient revealed generalized amyloidosis with multiorgan involvement by the disease. This case demonstrates that FNA can be a useful technique in the diagnosis of unsuspected amyloidosis. Diagn. Cytopathol. 2004;31:57,59. © 2004 Wiley-Liss, Inc. [source] SPE and large-volume sample stacking in MEKC for determination of doxycycline in biological fluids: Comparison of direct injection to SPE-MEKCELECTROPHORESIS, Issue 21 2008Rade Injac Abstract A novel and simple method has been developed for the determination of doxycycline (DOX) in biological fluids. The method is based on SPE, large-volume sample stacking (LVSS) and MEKC with UV-DAD detection. Six SPE cartridges have been used in investigation for sample clean up and pre-concentration (Supelco® LC-8, LC-18, LC-SCX, and LC-WCX, as well as StrataÔ-X and X-C). DOX was determined on a 56,cm (effective length 50,cm)×50,,m id fused-silica capillary. The BGE was 20,mM borate buffer, pH 9.3, containing 80,mM SDS and 7.5%,v/v of methanol (30,s×50,mbar), and the temperature and voltage were 25°C and 30,kV, respectively. The analytical wavelength was set at 210,nm. Under optimized conditions it is possible to determine DOX in human serum, urine, semen, tears and saliva with recovery of 97.5% (RSD 2.5%). The method was shown to be sensitive (LOD is 1,,g/L) and precise (intra-day RSD 0.2 and 2.4%; inter-days 0.4 and 3.5% for migration time and peak area, respectively). Results for developed SPE-LVSS-MEKC were compared with LVSS-MEKC method with direct sample injection. The new LVSS-MEKC method is presented as a useful technique for rapid determination without extraction procedure of DOX in human urine and serum, using 80,mM of SDS, 10%,v/v of methanol and 40,mM borate buffer (pH 9.3; 30,s×50,mbar; 25°C; 30,kV; 350,nm), but not for the other biological fluids, according to lower sensitivity of the method and because of the sample composition. [source] Uptake and diverse effects of polycyclic aromatic hydrocarbons on the metabolic activity of Elliptio complanata measured by calorespirometryENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2001Marcos A. Cheney Abstract Polycyclic aromatic hydrocarbons (PAHs) are important contaminants of world water resources, with effects on aquatic life. Metabolic responses to short-term acute toxicities of naphthalene, anthracene, and chrysene were investigated in the freshwater bivalve mollusk Elliptio complanata using differential scanning calorespirometry coupled with uptake and scanning electron microscopy. Comparing the uptakes of naphthalene, anthracene, and chrysene with that of inulin, which is known to occupy only extracellular space, showed that all compounds studied were taken up. The PAHs studied had diverse effects on the metabolic activity of E. complanata. Naphthalene and, to a lesser degree, chrysene caused stimulation of heat rates, possibly due to uncoupling of oxidative metabolism. Differential scanning calorespirometry coupled with studies of rates of oxygen consumption by the gill tissue exposed to the PAHs showed similar diverse patterns of respiratory rate stimulation and inhibition. Analysis of results of scanning electron microscopy suggested that irreversible damage to the gill tissue occurred in the presence of anthracene but not in the presence on naphthalene or chrysene. The batch calorespirometric method coupled with uptake and spectroscopy proved to be a useful technique to assess the toxicity of PAHs on the control of energy flux in gills of a freshwater bivalve mollusk. [source] PRECLINICAL STUDY: Morphine withdrawal decreases responding reinforced by sucrose self-administration in progressive ratioADDICTION BIOLOGY, Issue 2 2007Dengke Zhang ABSTRACT Previous studies have shown that withdrawal from psychostimulant drugs such as d -amphetamine or methamphetamine decreases motivation to work for a natural reinforcement, which is thought to be associated with the withdrawal-induced depressive state and hypofunction of the mesolimbic dopamine system. However, to our knowledge, studies exploring the effect of morphine withdrawal on motivation for a natural reinforcement are lacking. The purpose of the present study was to examine whether motivation to work for a natural reinforcement changes during morphine withdrawal. Three groups of male Sprague,Dawley rats were trained to respond on a nose poke for a 4% sucrose solution under a progressive ratio schedule and were subsequently administered a 10-day regimen of injection of high or low dose of morphine or saline. Their duration of break point and withdrawal symptoms were assessed. The finding showed that break points were significantly reduced on day 1 and persisted to at least day 10 of withdrawal without change in locomotor activity. There were hardly any differences bear mentioning when comparing the magnitude of the decrease between the high- and the low-dose group, whereas the withdrawal scales were significant greater in the high-dose group than in the low-dose group. The results suggest that the morphine withdrawal resulted in decreased motivation to obtain the natural reinforcement. The progressive ratio procedure may be a useful technique for evaluation of changes in motivation for natural reinforcing stimuli following withdrawal from opiates. [source] Short-term plasticity visualized with flavoprotein autofluorescence in the somatosensory cortex of anaesthetized ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2004Hiroatsu Murakami Abstract In the present study, short-term plasticity of somatosensory neural responses was investigated using flavoprotein autofluorescence imaging in rats anaesthetized with urethane (1.5 g/kg, i.p.) Somatosensory neural activity was elicited by vibratory skin stimulation (50 Hz for 1 s) applied on the surface of the left plantar hindpaw. Changes in green autofluorescence (, = 500,550 nm) in blue light (, = 450,490 nm) were elicited in the right somatosensory cortex. The normalised maximal fluorescence responses (,F/F) was 2.0 ± 0.1% (n = 40). After tetanic cortical stimulation (TS), applied at a depth of 1.5,2.0 mm from the cortical surface, the responses elicited by peripheral stimulation were significantly potentiated in both peak amplitude and size of the responsive area (both P < 0.02; Wilcoxon signed rank test). This potentiation was clearly observed in the recording session started 5 min after the cessation of TS, and returned to the control level within 30 min. However, depression of the responses was observed after TS applied at a depth of 0.5 mm. TS-induced changes in supragranular field potentials in cortical slices showed a similar dependence on the depth of the stimulated sites. When TS was applied on the ipsilateral somatosensory cortex, marked potentiation of the ipsilateral responses and slight potentiation of the contralateral responses to peripheral stimulation were observed after TS, suggesting the involvement of commissural fibers in the changes in the somatosensory brain maps. The present study clearly demonstrates that functional brain imaging using flavoprotein autofluorescence is a useful technique for investigating neural plasticity in vivo. [source] Structure of the HIV-1 Rev response element alone and in complex with regulator of virion (Rev) studied by atomic force microscopyFEBS JOURNAL, Issue 15 2009Jesper Pallesen The interaction of multiple HIV-1 regulator of virion (Rev) proteins with the viral RNA target, the Rev response element (RRE), is critical for nuclear export of incompletely spliced and unspliced viral RNA, and for the onset of the late phase in the viral replication cycle. The heterogeneity of the Rev,RRE complex has made it difficult to study using conventional structural methods. In the present study, atomic force microscopy is applied to directly visualize the tertiary structure of the RRE RNA alone and in complex with Rev proteins. The appearance of the RRE is compatible with the earlier proposed RRE secondary structure in dimensions and overall shape, including a stalk and a head interpreted as stem I, and stem-loops II,V in the secondary structure model, respectively. Atomic force microscopy imaging of the Rev,RRE complex revealed an increased height of the structure both in the stalk and head regions, which is in accordance with a binding model in which Rev binding to a high affinity site in stem IIB triggers oligomerization of Rev proteins through cooperative binding along stem I in RRE. The present study demonstrates that atomic force microscopy comprises a useful technique to study complex biological structures of nucleic acids at high resolution. [source] Targeted disruption of a pupal hemocyte protein of Sarcophaga by RNA interferenceFEBS JOURNAL, Issue 20 2001Takeshi Nishikawa Previously, we purified a transmembrane protein with a molecular mass of 120 kDa (p120) that is exclusively expressed in pupal hemocytes of Sarcophaga. In this study, we demonstrated that double-stranded RNA (dsRNA) injected into the larval body cavity effectively inhibited the expression of p120 in pupal hemocytes. Thus, RNA interference (RNAi) was found to be a useful technique for creating pupal hemocytes with a loss-of-function of a specific protein. The p120-less pupal hemocytes generated by RNAi were found to have lost the ability to take up acetylated low density lipoprotein, indicating that p120 is a scavenger receptor specifically expressed on the surface of pupal hemocytes. [source] Impact of the timing of stocking on growth and allometric index in aquaculture-based fisheriesFISHERIES MANAGEMENT & ECOLOGY, Issue 2 2004A. L. Ibáńez Abstract The impact of tilapia stocking on fisheries production in Lake Metztitlán was determined through progression analysis of modes obtained from (Gaussian) kernel density estimators (KDEs) of size frequency distributions of juvenile tilapia stocked after a period of total desiccation. The relationship between the allometric index of four cohorts and water temperature and variation in the volume of the basin was analysed. The use of KDEs was found to be a useful technique for the recognition and progression analysis of modes. The reasons for the low yields from the tilapia fishery of Lake Metztitlán are poor growth rate, low water temperature, which is manifest in low allometric indices, and the use of small mesh size nets. Yields can be sustained by improving fishery management; otherwise it is necessary to continue stocking. [source] 1D and 3D Ionic Liquid,Aluminum Hydroxide Hybrids Prepared via an Ionothermal Process,ADVANCED FUNCTIONAL MATERIALS, Issue 14 2007S. Park Abstract Room-temperature ionic liquids (RTILs) are used as hierarchically multifunctional components by employing them not only as templates and co-solvents for fabricating nanostructured materials but also proton conductors for electrochemical devices. RTIL/aluminum hydroxide (RTIL,Al) hybrids containing various nanometer-sized shapes, including 1D nanorods with hexagonal tips, straight and curved nanofibers, nanofibers embedded in a porous network, and 3D octahedral-, polyhedral-, and angular spherical shapes are synthesized via a one-pot ionothermal process. The structures or shapes of the RTIL,Al hybrids are related to the anionic moieties, alkyl chain length of the RTILs, and the humidity during fabrication. In particular, the introduction of water molecules into the interface led to 3D isotropic growth of the hybrids by influencing intermolecular interactions between the RTILs and the building blocks. The shapes of the nanohybrids fabricated from RTILs containing short alkyl chains were dependent on the types of anions and on the level of humidity. These results indicate that the cooperative interactions between RTILs and aluminum hydroxides induces emerging shape-controlled hybrids. The shape-controlled nanohybrids show enhanced electrochemical properties compared to those of a conventional hybrid prepared by mixing RTILs and aluminum hydroxides, exhibiting tenfold or higher proton conductivity under anhydrous condition and thermal stability as a result of the continuous proton conduction channel and the one-pot-assembled nanoconfinement. This method is expected to be a useful technique for controlling the diverse shapes of nanometer-sized crystalline inorganic materials for a variety of applications, such as fuel cells, solar cells, rechargeable batteries, and biosensors. [source] Testing and improving experimental parameters for the use of low molecular weight targets in array-CGH experiments,HUMAN MUTATION, Issue 11 2006Marianne Stef Abstract Array,comparative genomic hybridization (CGH) has evolved as a useful technique for the detection and characterization of deletions, and, to a lesser extent, of duplications. The resolution of the technique is dictated by the genomic distance between targets spotted on the microarray, and by the targets' sizes. The use of region-specific, high-resolution microarrays is a specific goal when studying regions that are prone to rearrangements, such as those involved in deletion syndromes. The aim of the present study was to evaluate the best experimental conditions to be used for array-CGH analysis using low molecular weight (LMW) targets. The parameters tested were: the target concentration, the way LMW targets are prepared (either as linearized plasmids or as purified PCR products), and the way the targets are attached to the array-CGH slide (in a random fashion on amino-silane coated slides, or by one amino-modified end on epoxysilane-coated slides). As a test case, we constructed a microarray harboring LMW targets located in the CREBBP gene, mutations of which cause the Rubinstein-Taybi syndrome (RTS). From 10 to 15% of RTS patients have a CREBBP deletion. We showed that aminosilane- and epoxysilane-coated slides were equally efficient with targets above 1,000,bp in size. On the other hand, with the smallest targets, especially those below 500,bp, epoxysilane-coated slides were superior to aminosilane-coated slides, which did not allow deletion detection. Use of the high resolution array allowed us to map intragenic breakpoints with precision and to identify a very small deletion and a duplication that were not detected by the currently available techniques for finding CREBBP deletions. Hum Mutat 27(11), 1143,1150, 2006. © 2006 Wiley-Liss, Inc. [source] Shape-prediction of 3D PTFE Microstructures Fabricated by Synchrotron Radiation AblationIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 2 2010Mitsuhiro Horade Non-member Abstract This article describes the calculation of the predictions of the deformed shapes of three-dimensional polytetrafluoroethylene (PTFE) microstructures fabricated by direct etching with a synchrotron radiation (SR) light source. As PTFE is a remarkable material, there is a lot of expectation regarding its applications in various devices. We did research on establishing a highly accurate three-dimensional technology for microfabricating PTFE by using an SR-light source because we aimed at applying this material in future devices. We built a shape-prediction technique as part of this research. Since this technique had the advantage of predicting shapes without experimentation, both fabrication time and cost could be reduced. It is also a useful technique for investigating and clarifying processing mechanisms. We compared structures fabricated in an experiment and the shapes computed with shape-prediction. The shape-prediction results were mostly in agreement with those from the experiment. As PTFE demonstrated excellent material characteristics, especially in its resistance to chemicals, it should be possible to use it in the fabrication of micro total analysis systems (µ-TAS) for biomedical applications. We expect that these applications will benefit from (based on) the designs which are predicted utilizing this calculation method. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Numerical modelling of compensation grouting above shallow tunnelsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 5 2005C. Wisser Abstract This paper describes the development of a numerical model for compensation grouting which is a useful technique for the protection of surface structures from the potentially damaging movements arising from tunnel construction. Pipes are inserted into the ground between the tunnel and the overlaying structure from an access shaft. Buildings on the surface are instrumented and movements are carefully monitored. Once the deformations exceed a certain Trigger Level, grout is injected into the ground to prevent damage. In the finite element model described here, compensation grouting is modelled by applying an internal pressure to zero-thickness interface elements embedded in the mesh. An ,observational algorithm' is used, where the deformations of the surface are monitored and used to control the injection process. Example analyses of compensation grouting are given for three-dimensional tunnel construction underneath a greenfield site. Different strategies are used to control the injection process and their effectiveness in preventing surface movement is assessed. The numerical model is shown to replicate general behaviour expected in the field and is capable of modelling the control of ground surface movements at a greenfield site. Copyright © 2005 John Wiley & Sons, Ltd. [source] Aerodynamic shape optimization on overset grids using the adjoint methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2010Wei Liao Abstract This paper deals with the use of the continuous adjoint equation for aerodynamic shape optimization of complex configurations with overset grids methods. While the use of overset grid eases the grid generation process, the non-trivial task of ensuring communication between overlapping grids needs careful attention. This need is effectively addressed by using a practically useful technique known as the implicit hole cutting (IHC) method. The method depends on a simple cell selection process based on the criterion of cell size, and all grid points including interior points and fringe points are treated indiscriminately in the computation of the flow field. This paper demonstrates the simplicity of the IHC method for the adjoint equation. Similar to the flow solver, the adjoint equations are solved on conventional point-matched and overlapped grids within a multi-block framework. Parallel computing with message passing interface is also used to improve the overall efficiency of the optimization process. The method is successfully demonstrated in several two- and a three-dimensional shape optimization cases for both external and internal flow problems. Copyright © 2009 John Wiley & Sons, Ltd. [source] The purse-string suture revisited: a useful technique for the closure of cutaneous surgical woundsINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 4 2007Philip R. Cohen MD The purse-string suture provides complete or partial closure of round postoperative skin defects. It is a rapid and simple procedure to perform. Tension placed on the suture uniformly advances the skin from the entire periphery of the wound, resulting in a significant reduction of the defect size and enhancement of hemostasis at the wound edge. The history, modifications of the technique, advantages, and potential complications of the purse-string suture are reviewed. It is not only useful following the removal of nonmelanoma skin cancer but also after the local excision of melanoma. In addition, this technique is especially suitable for the repair of round surgical wounds for patients who are unable to modify their active lifestyles during the week following surgery, individuals concurrently being treated with anticoagulants, antiplatelet agents or both, and people with extensive postoperative defects that would otherwise require either a skin graft or a large cutaneous flap. Typically, the site of the surgical wound following partial or complete closure with the purse-string suture demonstrates excellent long-term cosmetic and functional results. [source] Factors controlling the spatial species richness pattern of four groups of terrestrial vertebrates in an area between two different biogeographic regions in northern SpainJOURNAL OF BIOGEOGRAPHY, Issue 4 2004David Nogués-Bravo Abstract Aim, To examine the influence of environmental variables on species richness patterns of amphibians, reptiles, mammals and birds and to assess the general usefulness of regional atlases of fauna. Location, Navarra (10,421 km2) is located in the north of the Iberian Peninsula, in a territory shared by Mediterranean and Eurosiberian biogeographic regions. Important ecological patterns, climate, topography and land-cover vary significantly from north to south. Methods, Maps of vertebrate distribution and climatological and environmental data bases were used in a geographic information systems framework. Generalized additive models and partial regression analysis were used as statistical tools to differentiate (A) the purely spatial fraction, (B) the spatially structured environmental fraction and (C) the purely environmental fraction. In this way, we can evaluate the explanatory capacity of each variable, avoiding false correlations and assessing true causality. Final models were obtained through a stepwise procedure. Results, Energy-related features of climate, aridity and land-cover variables show significant correlation with the species richness of reptiles, mammals and birds. Mammals and birds exhibit a spatial pattern correlated with variables such as aridity index and vegetation land-cover. However, the high values of the spatially structured environmental fraction B and the low values of the purely environmental fraction A suggest that these predictor variables have a limited causal relationship with species richness for these vertebrate groups. An increment in land-cover diversity is correlated with an increment of specific richness in reptiles, mammals and birds. No variables were found to be statistically correlated with amphibian species richness. Main conclusions, Although aridity and land-cover are the best predictor variables, their causal relationship with species richness must be considered with caution. Historical factors exhibiting a similar spatial pattern may be considered equally important in explaining the patterns of species richness. Also, land-cover diversity appears as an important factor for maintaining biological diversity. Partial regression analysis has proved a useful technique in dealing with spatial autocorrelation. These results highlight the usefulness of coarsely sampled data and cartography at regional scales to predict and explain species richness patterns for mammals and birds. The accuracy of models appears to be related to the range perception of each group and the scale of the information. [source] Creating Continuous Linear Lesions in the Atria: A Comparison of the Multipolar Ablation Technique Versus the Conventional Drag-and-BurnJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2005WILBER W. SU M.D. Introduction: Catheter-based treatment of atrial fibrillation (AF) requires the isolation of the triggering foci as well as modification of the atria with substrate that sustains AF. The creation of linear lesions in the left atrium with standard radiofrequency ablative methods requires long procedural times with unpredictable results. Methods: The simultaneous delivery of phase-shifted radiofrequency energy from a multipolar catheter was compared to the conventional drag-and-burn technique for creating linear lesions in 10 dogs. Four atrial sites were targeted under intracardiac ultrasound and fluoroscopic guidance in each of 10 dogs. The conventional drag-and-burn technique or the multipolar phase-shifted ablation catheter was randomly applied for 60 seconds and compared. Results: Creating linear lesions using the simultaneous multipolar phase-shifted ablation catheter was on average 11.0 minutes faster (33.6 minutes vs 44.6 minutes, P < 0.01) than the drag-and-burn method. The fraction of the lesion length achieved using phase-shifted ablation compared to that intended was 23% greater (76% vs 53%, P < 0.01), and has less discontinuities (0.1 compared to 0.8 discontinuities/line, P < 0.003). There was no significant difference in either the lesion transmurality, or fluoroscopy times. Conclusion: The simultaneous delivery of phase-shifted, radiofrequency energy using a multipolar catheter is more effective and efficient in producing linear lesions than the traditional drag-and-burn technique. Using the multipolar ablative method to create linear lesions may be a useful technique in the treatment of patients with substrate-mediated atrial fibrillation. [source] Use of transrectal ultrasound-guided biopsy in the diagnosis of pelvic malignanciesJOURNAL OF CLINICAL ULTRASOUND, Issue 9 2006Ludwig Rinnab MD Abstract Purpose. To describe our experience with transrectal ultrasound (TRUS)-guided needle biopsy of pelvic malignancies. Methods. Eleven patients with clinical suspecion of advanced malignant pelvic tumor were referred to our institution with a history of unsuccessful CT-guided biopsy, although a target lesion was demonstrated on pelvic CT or MRI. Cholin-PET and FDG-18-PET were also obtained individually in each patient. TRUS was performed using a commercially available three-dimensional scanner. Biopsies were performed with an 18G biopsy gun. In 9 of 11 patients, biopsy was successfully performed under analgesia, whereas general anesthesia was required in the other 2 patients. Results. The lesions were identified with TRUS in all patients, and biopsies were taken successfully under TRUS guidance. In all patients, the harvested material was of excellent quality and was adequate for definitive pathological diagnosis. Pathological results included 6 nodal metastases from transitional cell carcinoma, 1 case of lymph node metastasis from prostate cancer, 1 paravesical recurrence of cervical cancer, 1 metastasis from cecal cancer, and 2 cases of paravesical metastasis of a gastric cancer. Conclusion. TRUS-guided biopsy is a useful technique for the diagnosis of pelvic malignancies. It is faster and less expensive than CT-guided biopsy, and in most cases sufficient material can be harvested for a definitive pathological diagnosis. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound, 2006 [source] Detection and differential diagnosis of hepatic masses using pulse inversion harmonic imaging during the liver-specific late phase of contrast enhancement with levovistJOURNAL OF CLINICAL ULTRASOUND, Issue 4 2002Cem Yücel MD Abstract Purpose The purpose of this study was to investigate whether late-phase pulse inversion harmonic imaging (PIHI) increases conspicuity in hepatic masses, helps to differentiate benign from malignant lesions, and demonstrates a greater number of and smaller metastatic lesions than do conventional (fundamental) sonography and helical CT. Methods Thirty patients (17 women and 13 men; age range, 35,77 years; mean age, 54 years) with known or suspected liver masses were evaluated using both fundamental sonography and contrast-enhanced PIHI during the liver-specific late phase of Levovist. The patients also underwent contrast-enhanced triphasic helical CT examinations within 1 week after sonography. In 4 of the patients, gadolinium-enhanced MRI was also performed as a part of their clinical work-up. Results The increase in the lesions' conspicuity on PIHI compared with fundamental sonography was significantly greater in malignant lesions than in benign lesions (p< 0.001). An echogenic rim was observed on PIHI in 8 (53%) of 15 malignant lesions. The mean number of metastatic lesions visualized on PIHI (5.5 ± 5.3) was significantly higher than the mean number visualized on fundamental sonography (2.5 ± 2.1, p < 0.05). Although lesions as small as 3 mm were observed on PIHI, the mean sizes of the smallest lesions demonstrated using fundamental sonography, PIHI, and helical CT were not significantly different. Conclusions Late-phase PIHI is a useful technique for characterizing hepatic lesions and demonstrating both a greater number of and smaller metastases. It may help to differentiate benign from malignant liver masses and may obviate unnecessary and expensive further imaging. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:203,212, 2002; Published online in Wiley InterScience (www.interscience. wiley.com). DOI: 10.1002/jcu.10053 [source] Measuring diagnostic and predictive accuracy in disease management: an introduction to receiver operating characteristic (ROC) analysisJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 2 2006Ariel Linden DrPH MS Abstract Diagnostic or predictive accuracy concerns are common in all phases of a disease management (DM) programme, and ultimately play an influential role in the assessment of programme effectiveness. Areas, such as the identification of diseased patients, predictive modelling of future health status and costs and risk stratification, are just a few of the domains in which assessment of accuracy is beneficial, if not critical. The most commonly used analytical model for this purpose is the standard 2 × 2 table method in which sensitivity and specificity are calculated. However, there are several limitations to this approach, including the reliance on a single defined criterion or cut-off for determining a true-positive result, use of non-standardized measurement instruments and sensitivity to outcome prevalence. This paper introduces the receiver operator characteristic (ROC) analysis as a more appropriate and useful technique for assessing diagnostic and predictive accuracy in DM. Its advantages include; testing accuracy across the entire range of scores and thereby not requiring a predetermined cut-off point, easily examined visual and statistical comparisons across tests or scores, and independence from outcome prevalence. Therefore the implementation of ROC as an evaluation tool should be strongly considered in the various phases of a DM programme. [source] Percutaneous radiofrequency ablation of renal tumours: Case series of 11 tumours and review of published workJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 5 2007TW Watkins Summary Detection of renal cell carcinoma (RCC) is increasing with the greater use of cross-sectional imaging and up to two-thirds of RCCs are discovered incidentally in asymptomatic patients. The traditional option of nephrectomy or partial nephrectomy may not always be appropriate. A minimally invasive treatment alternative is radiofrequency ablation (RFA). We retrospectively reviewed the RFA cases for renal tumours at our institution between January 2004 and June 2006. Thirteen RFA treatment sessions were conducted for 11 neoplasms in 11 patients. Mean patient age was 74.4 years (61,88 years). Imaging was carried out after ablation with a mean follow up of 8.0 months (2,26 months). No residual tumour was observed after the first RFA treatment in 82% of patients (nine of 11). Two patients required a second RFA treatment for residual (one) or recurrent tumour (one). RFA is emerging as a useful technique for treatment of small renal tumour. A number of short-term studies reflect this, however, long-term findings are still lacking. [source] Opaque maxillary antrum: A pictorial reviewJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 3 2005A Whyte Summary The demonstration of an opaque antrum on a plain radiograph or cross-sectional imaging leads to consideration of an extensive differential diagnosis. Relevant clinical details narrow the differential and include the patient's age, signs and symptoms, a history of recent trauma, prior surgery or dental treatment. Computed tomography remains the most useful technique in coming to a specific diagnosis. Magnetic resonance imaging adds specificity in a few selected situations and is required in conjunction with CT in the staging of malignant tumours. [source] | ||||||||||||||||||||||||||||||||||||||||||||||