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Selected AbstractsAmalgam Electrodes for ElectroanalysisELECTROANALYSIS, Issue 8 2003Øyvind Mikkelsen Abstract Liquid mercury is a unique material for the indicator electrode in voltammetry. One reason for this is the high overvoltage for hydrogen formation, thus extending the actual potential window. Diluted amalgams are important reaction products in voltammetric (polarographic) processes, however liquid amalgams are rarely used directly as electrode material for analytical purposes. Because of the fact that voltammetry is very suitable for field and remote monitoring, issues concerning the use of mercury electrodes in environmental analyses have led to considerable research effort aimed at finding alternative tools with acceptable performance. Solid electrodes are such alternatives. Different types of electrodes are reviewed. In particular, solid amalgam electrodes are very promising, with acceptable low toxicity to be used for field measurements. Solid amalgam electrodes are easy and cheap to construct and are stable over a reasonable time up to several weeks. Assessment of the toxicity risk and the long time stability for remote and unattended monitoring is discussed. The differences between solid dental amalgam electrodes, made by using techniques known from dental clinical practice, and mercury film or mercury layer electrodes on solid substrates are reviewed. In particular the dental technique for constructing solid amalgam electrodes gives advantage because it's fast and inexpensive. Also the technique for making dental amalgam has been explored and optimized over years by dentists, giving advantage when the same technique is used for constructing electrodes. Dental amalgam electrodes has been found to act similar to a silver electrodes, but with high overvoltage towards hydrogen. This make it possible to use the dental amalgam electrode for detection of zinc, cobalt and nickel in additions to other metals like lead, copper, thallium, cadmium, bismuth, iron etc. Also the use for reducible organic compounds is expected to be promising. [source] A study of endodontic treatment carried out in dental practice within the UKINTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2001S. M. Jenkins Abstract Aim The purpose of this study was to gather both qualitative and quantitative information on the nature of root canal treatment carried out by a group of dentists working within the United Kingdom. Methodology A two-part questionnaire was posted to 720 dentists who graduated from the Dental School, Cardiff, Wales, UK. The first part requested basic information regarding age, year of qualification, field of practice, etc. The second part consisted of 15 questions on endodontic practice and root canal treatment. Results The response rate was 41.5%. Two hundred and ninety-nine questionnaires contained useful information. The majority of practitioners did not use rubber dam during root canal treatment. The vast majority (89%) exposed a radiograph with an instrument of known length in situ to gauge the ,working length', a small number relied upon tactile sensation. Most practitioners used local anaesthetic solution as an irrigant during instrumentation of the root canal. A wide variety of instruments were used for root canal treatment; a stepback technique was preferred by almost half the practitioners. Antiseptic solution was preferred as an interappointment dressing. More than half of the respondents used laterally condensed gutta-percha to obturate root canals in anterior teeth but only one-third used the same technique in posterior teeth. Less than half the respondents exposed a radiograph to check the fit of the master point prior to obturation. Two-thirds of practitioners used a zinc oxide based material as their root canal sealer. Three-quarters of the practitioners exposed a post obturation radiograph. Conclusions The results of this study suggest that although some dentists are using the techniques taught during their undergraduate careers, a large percentage now use techniques with no evidence of clinical effectiveness. [source] Exchanging dual-lumen central venous catheters: How I do itJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 2 2007I Chaitowitz Summary The management of a blocked long-term central venous catheter has traditionally been removal and re-siting, even when device failure is not associated with venous thrombosis or sepsis. It is not possible to ,railroad' a split dual-lumen central venous catheter down a long tortuous s.c. tunnel. Our exchange technique was designed to salvage the tunnel and venous access site in a long-term catheter that has had uncomplicated primary device failure. In this technique we divide the dual-lumen catheter and secure the venous access site and the s.c. tunnel with separate peel-away sheaths. The new catheter is then introduced in the conventional manner through the two peel-away sheaths, which are then removed. The key advantage of the technique is that it preserves one of the few central venous access sites available. This article describes exchange of an internal jugular catheter, but the same technique is applicable to subclavian catheters. [source] The efficacy of cylindrical titanium mesh cage for the reconstruction of a critical-size canine segmental femoral diaphyseal defectJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2006Ronald W. Lindsey Abstract The authors developed a novel technique for the reconstruction of large segmental long bone defects using a cylindrical titanium mesh cage (CTMC). Although the initial clinical reports have been favorable, the CTMC technique has yet to be validated in a clinically relevant large animal model, which is the purpose of this study. Under general anesthesia, a unilateral, 3-cm mid-diaphyseal segmental defect was created in the femur of an adult canine. The defect reconstruction technique consisted of a CTMC that was packed and surrounded with a standard volume of morselized canine cancellous allograft and canine demineralized bone matrix. The limb was stabilized with a reamed titanium intramedullary nail. Animals were distributed into four experimental groups: in Groups A, B, and C (six dogs each), defects were CTMC reconstructed, and the animals euthanized at 6, 12, and 18 weeks, respectively; in Group D (three dogs), the same defect reconstruction was performed but without a CTMC, and the animals were euthanized at 18 weeks. The femurs were harvested and analyzed by gross inspection, plain radiography, computed tomography (CT), and single photon emission computed tomography (SPECT). The femurs were mechanically tested in axial torsion to failure; two randomly selected defect femurs from each group were analyzed histologically. Groups A, B, and C specimens gross inspection, plain radiography, and CT, demonstrated bony restoration of the defect, and SPECT confirmed sustained biological activity throughout the CTMC. Compared to the contralateral femur, the 6-, 12-, and 18-week mean defect torsional stiffness was 44.4, 45.7, and 72.5%, respectively; the mean torsional strength was 51.0, 73.6, and 83.4%, respectively. Histology documented new bone formation spanning the defect. Conversely, Group D specimens (without CTMC) demonstrated no meaningful bone formation, biologic activity, or mechanical integrity at 18 weeks. The CTMC technique facilitated healing of a canine femur segmental defect model, while the same technique without a cage did not. The CTMC technique may be a viable alternative for the treatment of segmental long bone defects. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1438,1453, 2006 [source] Pd membranes formed by electroless plating with osmosis: H2 permeation studiesAICHE JOURNAL, Issue 2 2002Razima S. Souleimanova The synthesis of fully dense Pd-Vycor glass composite membranes by electroless plating with or without osmosis is reported. Use of osmotic flux allows one to rapidly form thin (a few microns), fully dense palladium films, which have submicron size microstructure. These features significantly enhance hydrogen permeability as compared to the conventional method. By accounting for resistance of the porous support, it is confirmed that for membranes prepared by the same technique, with gradually changing microstructural characteristics, those with smaller palladium crystallites exhibit larger hydrogen flux. Pd-stainless steel composite membranes were also prepared using electroless plating, either with or without osmosis. Membranes synthesized using osmosis exhibit superior thermal stability. [source] In vitro and in vivo identification of ,pseudocatalase' activity in Dead Sea water using Fourier transform Raman spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 7 2002Karin U. Schallreuter Balneotherapy with Dead Sea water has been reported as a successful treatment modality for psoriasis, atopic eczema and vitiligo, but the precise mode of action has escaped definition so far. The saturating salt concentration (346 g/litre) together with the unique UV spectrum have been suggested to trigger the release of pro-inflammatory and chemotactic mediators. The results of our study show for the first time a high content of transition metal ions (manganese, iron and copper) in Dead Sea water. Using in vitro Fourier transform (FT) Raman spectroscopy, we were able to identify ,pseudocatalase' activity by observing the decomposition of hydrogen peroxide (H2O2) over time by Dead Sea water. Since patients with vitiligo accumulate millimolar levels of H2O2 in their skin, we followed the degradation of H2O2in vivo again utilizing the same technique. The results of this in vitro and in vivo study show for the first time a ,pseudocatalase' activity of Dead Sea water and provide evidence that the antioxidant properties of Dead Sea water bathing could play an important role in this unique treatment modality. Furthermore, the use of non-invasive in vivo FT-Raman spectroscopy introduces an excellent biomedical application in investigative dermatology. Copyright © 2002 John Wiley & Sons, Ltd. [source] Detection of hazardous reaction products during a thermal runawayPROCESS SAFETY PROGRESS, Issue 2 2003Ronald J. A. Kersten The control of major accident hazards linked with the storage and processing of dangerous substances in chemical and petrochemical installations is regulated in the European Union by the so-called "Seveso II Directive." One of the requirements in this Directive is the declaration of not only the hazardous substances as present onsite, but also any hazardous products that could form during a loss of control situation. This study focused on the development of an experimental technique to determine the substances that might be formed during an uncontrolled chemical reaction or runaway reaction. The decomposition reaction of a diazo compound was studied with the technique to assess its applicability. The results show that, apart from its applicability in relation to the Seveso II Directive, the same technique can be used to obtain data for the design of gas treatment systems or to study the mechanism behind runway reactions. Understanding this mechanism, in turn, helps to identify conditions that might favor the occurrence of, or might temper the course of, the runaway reaction. [source] Faculty-development activity to promote effective communication between instructors and studentsTHE CLINICAL TEACHER, Issue 2 2010Netta Notzer Summary Background:, Educators claim that conflicts and teacher,student miscommunications interfere in achieving optimal learning outcomes. Context:, Conflicts arise when clinical instructors communicate in a patronising fashion, expressing values that are not those of their medical students. This paper presents our approach of coping with such conflicts. It is based on the notion that language is comprised of developmental levels. The objective is to switch the instructor's lower level of language from an uncontrolled reaction to a high level of efficient communication. Innovation:, During our faculty-development workshops, we piloted sessions consisting of vignettes depicting instructor,student conflicts. The workshop participants were asked to react and discuss questions on their feelings in similar conflicts, and their immediate speech reaction to students. The workshop's facilitator pointed out that there was no one right solution. She singled out the reaction that takes into account the student's personality, avoiding imposing solutions. The feedback on these sessions was very favourable, indicating a high level of satisfaction. Implications:, The positive feedback is very encouraging. We believe that our workshops amplify the desired effective instructor,student communication, and suggest that the success of this intervention is partly achieved by selecting problematic issues of communication, and adjusting them to the current needs of our faculty members. In order to reproduce our approach, we suggest that other institutions should define their own values and communication code. We recommend them to use the same technique of intervention among a small group in an empowering atmosphere of discussion, using their own situations. [source] Brief Communication: No-Touch Hepatic Hilum Technique to Treat Early Portal Vein Thrombosis After Pediatric Liver TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 9 2010J. Bueno A ,no-touch' hilum technique used to treat early portal vein complications post-liver transplantation in five children with body weight <10 kg is described. Four patients developed thrombosis and one portal flow absence secondary to collateral steal flow. A vascular sheath was placed through the previous laparotomy in the ileocolic vein (n = 2), inferior mesenteric vein (n = 1) or graft umbilical vein (n = 1). Portal clots were mechanically fragmented with balloon angioplasty. In addition, coil embolization of competitive collaterals (n = 3) and stent placement (n = 1) were performed. The catheter was left in place and exteriorized through the wound (n = 2) or a different transabdominal wall puncture (n = 3). A continuous transcatheter perfusion of heparin was subsequently administered. One patient developed recurrent thrombosis 24 h later which was resolved with the same technique. Catheters were removed surgically after a mean of 10.6 days. All patients presented portal vein patency at the end of follow-up. Three patients are alive after 5 months, 1.5 and 3.5 years, respectively; one patient required retransplantation 18 days postprocedure and the remaining patient died of adenovirus infection 2 months postprocedure. In conclusion, treatment of early portal vein complications following pediatric liver transplantation with this novel technique is feasible and effective. [source] HS07 TOE TRANSFER , TECHNIQUES & RESULTSANZ JOURNAL OF SURGERY, Issue 2007L. C. Teoh Toe to thumb-finger transfer requires the understanding of microsurgery and reconstructive technique. The success is measured by the viability of the toe and eventually recreating the function of the original loss. In harvesting of the toe, the big and second toe follows almost the same technique. Identifying the toe artery over the first web space and then dissecting proximally into the intermetatarsal artery is the best approach. To dissect the artery from proximal to distal is often fraught with many dangers. In my cases about 50% the plantar artery is dominant. Anticipation and planning of the artery length is crucial. In toe to thumb transfer the choice can be 2nd toe, total big toe, trimmed big toe or wrap around transfer. In our local populations, 2nd toe is always a good choice. First reconstruction with flap resurfacing may be necessary if the thumb amputation is very proximal. Toe to fingers transfer is usually indicated in 4 finger loss of the hand. In toe to finger transfer I prefer the two 2nd toes transfer into the middle and ring finger position. As the transferred toes can regain less that 50% of motion, the positioning of the toes should be opposable to the thumb. The concept of total reconstruction should be closely followed. Stable skeletal fixation, tendon weave technique, good nerve repair, adequate skin coverage and primary healing are important to ensure good outcome result. [source] A GEOARCHAEOLOGICAL STUDY OF THE ANCIENT QUARRIES OF SIDI GHEDAMSY ISLAND (MONASTIR, TUNISIA)ARCHAEOMETRY, Issue 4 2010M. E. GAIED Amongst a large number of ancient quarries scattered along the North African coast, those at Sidi Ghedamsy (Monastir, Tunisia) have supplied building stones of Pliocene age. Two lithofacies have been distinguished in the quarry faces: (i) fine sandy limestone, which has been used in the construction of Roman and Arabic monuments; and (ii) porous and coarse limy sandstone, which is of bad quality for construction. Laboratory analysis results confirm that the exploitation of stone in antiquity was well focused on the levels containing the first type. This is confirmed by geotechnical tests, which show that the fine sandy limestone is harder and less porous than the coarse limy sandstone. Extraction of these stones began in the Roman period. The Romans exploited the quarries using steel tools that permitted the extraction of blocks from several levels. In the eighth century, Arabic quarry workers continued the stone extraction using the same technique, but they produced blocks of small and medium size. Statistical measurements have been done on the quarry faces and on the walls of the Ribat in order to understand the degree of conformity between the dimensions of the extracted blocks and those used for building, and ultimately to attempt to date the quarries and the construction of the Ribat. [source] Conformation of , zeins in solid state by Fourier transform IRBIOPOLYMERS, Issue 6 2003Lucimara A. Forato Abstract The major maize storage proteins (, zeins) are deposited as an insoluble mass in the protein bodies of the endosperm. Because they are insoluble in water, most structural studies are performed in alcohol solutions. To solve the question raised by several authors about denaturation of the , zein structure by alcohol, we analyze the secondary structure of , zeins prepared with and without solubilization in alcohol (corn gluten meal and protein bodies with high concentrations of , zeins and traces of , zeins). The secondary structures of , zeins are analyzed in the solid state by Fourier transform IR spectroscopy (FTIR) in KBr pellets and solid-state 13C-NMR spectroscopy. The proportion of secondary structures obtained by FTIR of , zeins prepared with and without solubilization in alcohol yield almost identical proportions of , helices and , sheets. The proportion of , helices (43%) agrees with that measured by circular dichroism in an alcohol solution. However, the proportion of , sheets (28%) is higher than the one measured by the same technique. Gluten and protein body samples with high , zein content showed higher , sheet and lower , helix proportions than that obtained for , zein preparations. The solid-state 13C-NMR spectra show the carbonyl peak for the , zeins at , 176 and for the sample rich in , zeins at , 172, which demonstrates the presence of a high content of , helices and , sheets, respectively. These results indicate that alcohol solubilization does not affect the conformation of , zeins, validating the secondary structure measurements in solution. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy), 2003 [source] Crystallization and preliminary crystallographic analysis of the transcriptional regulator RfaH from Escherichia coli and its complex with ops DNAACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 10 2006Marina N. Vassylyeva The bacterial transcriptional factor and virulence regulator RfaH binds to rapidly moving transcription elongation complexes through specific interactions with the exposed segment of the non-template DNA strand. To elucidate this unusual mechanism of recruitment, determination of the three-dimensional structure of RfaH and its complex with DNA was initiated. To this end, the Escherichia coli rfaH gene was cloned and expressed. The purified protein was crystallized by the sitting-drop vapor-diffusion technique. The space group was P6122 or P6522, with unit-cell parameters a = b = 45.46, c = 599.93,Å. A complex of RfaH and a nine-nucleotide oligodeoxyribonucleotide was crystallized by the same technique, but under different crystallization conditions, yielding crystals that belonged to space group P1 (unit-cell parameters a = 36.79, b = 44.01, c = 62.37,Å, , = 80.62, , = 75.37, , = 75.41°). Complete diffraction data sets were collected for RfaH and its complex with DNA at 2.4 and 1.6,Å resolution, respectively. Crystals of selenomethionine-labeled proteins in both crystal forms were obtained by cross-microseeding using the native microcrystals. The structure determination of RfaH and its complex with DNA is in progress. [source] Diffusion of Medical Progress: Early Spinal Immobilization in the Emergency DepartmentACADEMIC EMERGENCY MEDICINE, Issue 11 2007Mark Hauswald MD Objectives: To examine the spread of new techniques of spinal care through one state's emergency departments (EDs). Methods This was a telephone survey of all 36 EDs in a single state. One physician from each ED was contacted and given a short structured survey instrument to determine when patients who arrived at the ED on backboards were removed from the backboards. Removal was classified as "immediate" if it was done before clinical or radiographic exclusion of cervical spine injury and "delayed" if it was done only after interpretation of any indicated diagnostic radiologic procedures. Further questions were asked to determine if all physicians in the group used the same technique and how this technique had been adopted. Results In all but four hospitals, patients were removed from backboards in the same manner by all physicians, using a protocol or standard procedure. Fifteen of these did immediate and seventeen did delayed removal. In all but one case, the approach of immediate removal was initiated at the hospital by a physician trained or recently working at a university facility. Eight respondents stated that transport service requirements influenced their decision. Conclusions Although logic and the medical literature support removing all patients from a backboard immediately, physicians were unlikely to change their practice after their formal training had been completed until a new member of their group had done so. [source] | |||||||||||||