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Variety Of Techniques (variety + of_techniques)
Selected AbstractsRetrospective Review of Reconstructive Methods of Conchal Bowl Defects Following Mohs Micrographic SurgeryDERMATOLOGIC SURGERY, Issue 5 2001Nina Wines BSc Background. Mohs micrographic surgery has consistently been demonstrated to be the most effective method for excision of potentially aggressive lesions of the conchal bowl. A variety of techniques are employed to reconstruct the conchal bowl following surgery. Objective. To explore the type and frequency of reconstruction techniques used and the factors influencing the surgeons choice of reconstruction method. Method. Retrospective analysis of 272 patients with conchal bowl tumors. Results. Split thickness skin grafting was the preferred method of reconstruction. The histopathology of the lesions and the size of the post-Mohs defect did not influence the choice of technique, except for lesions less than 1 cm in which healing by secondary intention was favored. Conclusion. Tumor size, type, and aggressiveness did not influence repair technique choice. Surgeon preference was therefore the principle factor dictating method of reconstructive technique following Mohs micrographic surgery. [source] Ooplasmic segregation in the zebrafish zygote and early embryo: Pattern of ooplasmic movements and transport pathwaysDEVELOPMENTAL DYNAMICS, Issue 8 2010Ricardo Fuentes Abstract Patterns of cytoplasmic movements and organization of transport pathways were examined in live or fixed zygotes and early zebrafish embryos using a variety of techniques. The zygote blastodisc grows by accumulation of ooplasm, transported to the animal pole from distinct sectors of ecto- and endoplasm at different speeds and developmental periods, using specific pathways or streamers. Slow transport (5 ,m/min) occurs during the first interphase along short streamers, whereas fast transport (9.6,40 ,m/min) takes place during the first cleavage division along axial and meridional streamers. Interconnections between streamers allow cargoes to change their speed and final destination. A similar sequence of events occurs during the following divisions. A complex network of microtubules and actin filaments in the endo- and ectoplasm appears to be involved in the transport of inclusions and mRNAs. Actin-dependent intermittent pulsations provoked high-speed back-and-forth movements of cytoplasm that may contribute to redistribution of organelles and maternal determinants. Developmental Dynamics 239:2172,2189, 2010. © 2010 Wiley-Liss, Inc. [source] The effects of chronic nitrogen fertilization on alpine tundra soil microbial communities: implications for carbon and nitrogen cyclingENVIRONMENTAL MICROBIOLOGY, Issue 11 2008Diana R. Nemergut Summary Many studies have shown that changes in nitrogen (N) availability affect primary productivity in a variety of terrestrial systems, but less is known about the effects of the changing N cycle on soil organic matter (SOM) decomposition. We used a variety of techniques to examine the effects of chronic N amendments on SOM chemistry and microbial community structure and function in an alpine tundra soil. We collected surface soil (0,5 cm) samples from five control and five long-term N-amended plots established and maintained at the Niwot Ridge Long-term Ecological Research (LTER) site. Samples were bulked by treatment and all analyses were conducted on composite samples. The fungal community shifted in response to N amendments, with a decrease in the relative abundance of basidiomycetes. Bacterial community composition also shifted in the fertilized soil, with increases in the relative abundance of sequences related to the Bacteroidetes and Gemmatimonadetes, and decreases in the relative abundance of the Verrucomicrobia. We did not uncover any bacterial sequences that were closely related to known nitrifiers in either soil, but sequences related to archaeal nitrifiers were found in control soils. The ratio of fungi to bacteria did not change in the N-amended soils, but the ratio of archaea to bacteria dropped from 20% to less than 1% in the N-amended plots. Comparisons of aliphatic and aromatic carbon compounds, two broad categories of soil carbon compounds, revealed no between treatment differences. However, G-lignins were found in higher relative abundance in the fertilized soils, while proteins were detected in lower relative abundance. Finally, the activities of two soil enzymes involved in N cycling changed in response to chronic N amendments. These results suggest that chronic N fertilization induces significant shifts in soil carbon dynamics that correspond to shifts in microbial community structure and function. [source] Physiological constraints on contest behaviourFUNCTIONAL ECOLOGY, Issue 4 2007M. BRIFFA Summary 1Contests may involve injurious fighting, other types of direct physical aggression and communication. They occur over ownership access to mates and other resources that may increase an individual's attractiveness and its chance of survival. Traits that enhance resource holding potential may be the result of sexual selection, natural selection or a combination of both. 2Agonistic behaviours are expected to be demanding to perform and costly in terms of changes in physiological state. The ability to meet the physiological costs may determine contest outcomes and constrain the intensity of agonistic activities. 3The energetic costs have been investigated in a broad range of taxa using a variety of techniques. They include the mobilization of energy reserves, but a key cost in several taxa appears to be limited anaerobic capacity and subsequent accumulation of lactic acid. Androgens, stress hormones and neurohormones have also been shown to constrain fighting behaviour. However, due to key differences in the endocrine systems of vertebrates and invertebrates, the effects of hormones are far less consistent across taxa than in the case of metabolites. 4Physiological constraints on fighting may vary according to their importance relative to circumstantial costs, the time-scale over which they exert their effects, their effects on different roles and their causal links with behaviour. Incorporating these factors into theoretical studies of contest behaviour may give further insights of how the costs of fighting influence agonistic behaviour. [source] One-Pot Synthesis of Functional Helicoidal Hybrid Organic,Inorganic Nanofibers with Periodically Organized MesoporosityADVANCED FUNCTIONAL MATERIALS, Issue 18 2009Frédéric Rambaud Abstract The one-pot synthesis and properties of multifunctional hybrid mesoporous organosilica fibers with helical shapes are described. These hybrid mesoporous fibers are prepared without chiral elements and functionalized with a large variety of organic R functions (R,=,alkylthiols, phenylsulfonates, alkylphosphonates, dansyl, aminopropyl, fluoroalkyl, etc.). The resulting nanomaterials are thoroughly characterized by a variety of techniques. The use of a synergetic combination of achiral molecules as co-directing structuring agents, a surfactant, and an organofunctional silica precursor R-Si(OR)3 allows, via carefully tuning of the main synthesis parameters and processing conditions, to control the shape, which is the anisotropic factor, of the hybrid nanofibers. The functionalization of the hybrid materials with fluorescent molecules (dansyl) and gold nanoparticles opens possibilities for sensor and catalytic applications, respectively. Moreover, these hybrid nanofibers can be easily transferred in organic solvents or in a "green" solvent such as water to make stable colloidal dispersions. This tunable functionality of nanofibers also allows their transferability into a variety of polymeric hosts (PVDF, PVBu, and PVP) allowing the formation of functional homogeneous nanocomposite hybrid membranes. [source] The role of static stress transfer in mining induced seismic events occurrence, a case study of the Rudna mine in the Legnica-Glogow Copper District in PolandGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2010B. Orlecka-Sikora SUMMARY Seismicity accompanying mining exploitation results from changes in the stress field in the rock mass near the mining excavations caused by human activity. Many studies of the temporal and spatial distribution of mining induced seismicity have provided evidence for interrelations among events. Although a variety of techniques have been applied to quantify the interdependences of mining induced seismic events, the physical mechanism of interactions has not been unequivocally identified. Based on the premise that one possible cause of interactions among seismic events can be static stress transfer, we have verified statistically the role of Coulomb stress transfer in the generation process of mining induced seismicity using a series of seismic events that occurred in the Rudna mine in the Legnica-G,ogów Copper District in Poland. We quantify the triggering and inhibiting effect by the proportion of events in the series, whose locations are consistent with the stress increased and stress decreased zones, respectively. We have found that more than 60 per cent of the analysed seismic events occurred in areas where stress was enhanced due to the occurrence of previous events. The statistical significance of these results is tested by comparing them with the same proportions obtained for 2000 random permutations of the original series of events. The test has indicated that the locations in positive stress changes areas are preferred statistically significantly when the stress changes exceed 0.05 bar. This result turns out to be robust to the errors of the nodal planes determination. [source] A Numerical Model and Spreadsheet Interface for Pumping Test AnalysisGROUND WATER, Issue 4 2001Gary S. Johnson Curve-matching techniques have been the standard method of aquifer test analysis for several decades. A variety of techniques provide the capability of evaluating test data from confined, unconfined, leaky aquitard, and other conditions. Each technique, however, is accompanied by a set of assumptions, and evaluation of a combination of conditions can be complicated or impossible due to intractable mathematics or nonuniqueness of the solution. Numerical modeling of pumping tests provides two major advantages: (1) the user can choose which properties to calibrate and what assumptions to make; and (2) in the calibration process the user is gaining insights into the conceptual model of the flow system and uncertainties in the analysis. Routine numerical modeling of pumping tests is now practical due to computer hardware and software advances of the last decade. The RADFLOW model and spreadsheet interface presented in this paper is an easy-to-use numerical model for estimation of aquifer properties from pumping test data. Layered conceptual models and their properties are evaluated in a trial-and-error estimation procedure. The RADFLOW model can treat most combinations of confined, unconfined, leaky aquitard, partial penetration, and borehole storage conditions. RADFLOW is especially useful in stratified aquifer systems with no identifiable lateral boundaries. It has been verified to several analytical solutions and has been applied in the Snake River Plain Aquifer to develop and test conceptual models and provide estimates of aquifer properties. Because the model assumes axially symmetrical flow, it is limited to representing multiple aquifer layers that are laterally continuous. [source] Temperature Responsive Solution Partition of Organic,Inorganic Hybrid Poly(N -isopropylacrylamide)-Coated Mesoporous Silica Nanospheres,ADVANCED FUNCTIONAL MATERIALS, Issue 9 2008Po-Wen Chung Abstract A series of poly(N -isopropylacrylamide)-coated mesoporous silica nanoparticle materials (PNiPAm-MSNs) has been synthesized by a surface-initiated living radical polymerization with a reversible addition,fragmentation chain transfer (RAFT) reaction. The structure and the degree of polymerization of the PNiPAm-MSNs has been characterized by a variety of techniques, including nitrogen sorption analysis, 29Si and 13C solid-state NMR spectroscopy, transmission electron microscopy (TEM), and powder X-ray diffraction (XRD). The thermally induced changes of the surface properties of these polymer-coated core,shell nanoparticles have been determined by examining their partition activities in a biphasic solution (water/toluene) at different temperatures. [source] Lithium Storage in Carbon NanostructuresADVANCED MATERIALS, Issue 25-26 2009Nitin A. Kaskhedikar Abstract In this review article we discuss the progress of lithium storage in different carbon forms starting from intercalation in graphite to the lithium storage in fullerenes, nanotubes, diamond and most recently, graphene. The recent advances in lithium storage in various novel morphological variants of carbons prepared by a variety of techniques are also discussed with the most important models in literature that have been set out to explain the excess lithium storage. The major emphasis lies on the real structure. [source] The Role of Processing in the Fabrication and Optimization of Plastic Solar CellsADVANCED MATERIALS, Issue 14-15 2009Jeffrey Peet Abstract The development of high-efficiency plastic solar cells is rapidly accelerating as the need for economically viable alternative energy sources becomes evident. Polymer-based bulk-heterojunction (BHJ) solar cells are attractive in that they can be coated from solution onto flexible substrates by a variety of techniques and thus inexpensive large-volume manufacturing should be possible. Further, the inherent flexibility of the polymeric materials combined with thin photovoltaic active layers results in devices that can be adapted to a variety of unique aesthetics and form factors. Recent advances in key relationships between thin-film casting methods, bulk-heterojunction morphology, and device performance have occurred in tandem with the synthesis of novel polymer semiconductors that possess increased optical-absorption breadth and optoelectronic performance. This Research News article highlights a few techniques developed to optimize the BHJ nanomorphology and performance of solar cells fabricated by various solution-processing methods. [source] Identifying Early Cardiovascular Disease to Target Candidates for TreatmentJOURNAL OF CLINICAL HYPERTENSION, Issue 3 2008Daniel A. Duprez MD Most attempts to identify individuals at risk for cardiovascular morbid events have involved screening for risk factors. These traditional risk factors do not identify the underlying atherosclerotic disease nor assess the severity of disease in individual patients. The goal for identifying a marker or markers for early cardiovascular disease that could serve as a surrogate for disease progression and ultimate morbid events is to improve the precision for early detection and treatment. The authors utilize a variety of techniques, which consist of 7 vascular tests (large and small artery elasticity, resting blood pressure and exercise blood pressure response, optic fundus photography, carotid intimal-media thickness, and microalbuminuria) and 3 cardiac tests (electrocardiography, [N-terminal pro-] B-type natriuretic peptide, and left ventricular ultrasonography). Each test is individually scored, and the total disease score is the sum of all the test scores. A study is ongoing to compare the new disease score vs the classical Framingham risk estimate in the prediction of cardiovascular events. [source] The efficacy of three different surgical techniques in the management of drug-induced gingival overgrowthJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2006M. Mavrogiannis Abstract Objectives: The aim of the present study was to evaluate the efficacy of three different surgical techniques in both the management and effect upon rate of overgrowth recurrence of drug-induced gingival overgrowth (DIGO). Materials and methods: Two cohorts of patients who required surgical correction of their DIGO participated in the study. After baseline periodontal measures (plaque index, gingival inflammation and probing pocket depths), the patients underwent surgery. A split-mouth, crossover design was used to compare conventional gingivectomy with flap surgery (n=27), and conventional gingivectomy with laser excision (n=23). The main outcome variable was the rate of recurrence of DIGO following surgery. Results: At 6 months, there was significantly less recurrence (p=0.05) in patients treated with laser excision, compared with those treated by conventional gingivectomy. The differences in rate of recurrence of DIGO were also reflected in changes in several periodontal parameters. Flap surgery offered no advantage over conventional gingivectomy with respect to the rate of recurrence. Conclusions: DIGO can be managed by a variety of techniques. Laser excision results in a reduced rate of recurrence. [source] Comparative effectiveness of hand and ultrasonic instrumentations in root surface planing in vitroJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 3 2004Mahmood Khosravi Abstract Background/aims: A variety of techniques are employed for planing and scaling of the superficial root surfaces, of which hand and ultrasonic instrumentations have been preferentially used in routine periodontics clinics. This study was undertaken to compare the effectiveness of ultrasonic scalers and hand curettes in facilitating fibroblast attachment to the scaled root surfaces. Materials and Methods: Sixteen patients with periodontally involved teeth and nine subjects without periodontal diseases (control subjects) were selected. Two single-rooted teeth were extracted from each subject. Mesial and distal surfaces of teeth were selected in treated and untreated groups, respectively. The mesial surface of each tooth was randomly chosen to be treated either by hand curettes or ultrasonic instrumentation. The degree of cell attachment on the root surfaces of treated and untreated groups from control subjects and patients was then determined by the use of a gingival fibroblast line established and employed at early passages. The attachment and proliferation of gingival fibroblasts on the root surfaces were evaluated using neutral red assay and scanning electron microscopy (SEM). Results: Fibroblast survival and proliferation on the surfaces of untreated periodontally involved roots were found to be significantly lower compared with control untreated surfaces (p<0.0001) or treated surfaces from patients (p<0.0001). No significant difference, however, was observed between root surfaces treated either by hand curettes or ultrasonic scalers. Conclusion: These results indicate the beneficial effectiveness of both techniques in root treatment and planing. [source] Cash disbursements: How to minimize cash outputJOURNAL OF CORPORATE ACCOUNTING & FINANCE, Issue 1 2008Rob Reider There is an art to effectively managing cash disbursements. The author shows how to use a variety of techniques to help you minimize cash output,and not get in trouble doing it. After you read this article, your motto will be "No Pay Before Its Time." This article is excerpted and adapted from Managing Cash Flow: An Operational Focus by Rob Reider, published by John Wiley & Sons, Inc. © 2008 Wiley Periodicals, Inc. [source] Catheter Closure of Coronary Artery FistulasJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 3 2001SHAKEEL A. QURESHI F.R.C.P. Coronary artery fistulas are rare and vary widely in their morphological appearance and presentation. This paper presents experience of catheter closure of coronary artery fistulas in 40 patients. Catheter closure was performed with a variety of techniques, including detachable balloons, stainless steel coils, controlled-release coils, controlled-release patent ductus arteriosus (PDA) coils, and Amplatzer PDA plug. The vast majority of the fistulas were occluded with coils and in particular, controlled-release coils. Successful occlusion of the fistula was achieved in 39 (97%) of 40 patients. In one patient, the detachable balloon deflated prematurely and the patient underwent elective surgery. One 4-month-old infant died approximately 6 hours after the procedure. Immediate occlusion of the coronary artery fistula occurred in 33 (82%) of patients and late occlusion in 4 patients. Thus overall, total occlusion was achieved in 37 (97%) of 39 patients. The main complication was embolization of the occlusion device, which occurred in 6 (17%) of cases. In one of these cases, a detachable balloon deflated prematurely, and in five patients, coils embolized and were retrieved. In one of the patients, all six coils embolized 24 hours after the procedure but were retrieved, and further coils were implanted successfully. Controlled-release coils have made an important contribution to the technique of catheter closure of coronary artery fistulas. Catheter closure of these fistulas is an acceptable alternative to the standard surgical treatment. [source] Current trends in quantitative proteomicsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 12 2009Monica H. Elliott Abstract It was inevitable that as soon as mass spectrometrists were able to tell biologists which proteins were in their samples, the next question would be how much of these proteins were present. This has turned out to be a much more challenging question. In this review, we describe the multiple ways that mass spectrometry has attempted to address this issue, both for relative quantitation and for absolute quantitation of proteins. There is no single method that will work for every problem or for every sample. What we present here is a variety of techniques, with guidelines that we hope will assist the researcher in selecting the most appropriate technique for the particular biological problem that needs to be addressed. We need to emphasize that this is a very active area of proteomics research,new quantitative methods are continuously being introduced and some ,pitfalls' of older methods are just being discovered. However, even though there is no perfect technique,and a better technique may be developed tomorrow,valuable information on biomarkers and pathways can be obtained using these currently available methods Copyright © 2009 John Wiley & Sons, Ltd. [source] Generation of core/shell iron oxide magnetic nanoparticles with polystyrene brushes by atom transfer radical polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2007I. Garcia Abstract The functionalization of nanoparticle surfaces is required to improve the dispersion of an inorganic material inside an organic matrix. In this work, polystyrene (PS) brushes were grown on the surface of iron oxide magnetic nanoparticles with atom transfer radical polymerization and a grafting-from approach. After polymerization, the magnetic nanoparticles had a graft density of 0.9 PS chains/nm2. A sacrificial initiator was used to obtain a satisfactory result for the control of the polymerization, as its addition had to generate a sufficient concentration of persistent radicals (deactivator). A variety of techniques, such as Fourier transform infrared spectroscopy, thermogravimetric analysis, gel permeation chromatography, water contact-angle measurements, and atomic force microscopy, were used to characterize the nanoparticles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4744,4750, 2007 [source] Screen Printing to Achieve Highly Textured Bi4Ti3O12JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2010Michael R. Winter The focus of this paper is to explore the efficacy of screen printing to generate crystalline texture in bismuth titanate through the orientation of highly anisotropic seed crystals. Seed crystals were grown through a molten salt flux technique with aspect ratios of ,100:1, mixed with equiaxed powder of the same composition and oriented using screen printing, a high shear process. By printing on a flexible polymer substrate and using multiple print/dry cycles, it was possible to create pads with a thickness of several hundred micrometers and to remove the dried pads, creating free-standing samples. Upon sintering, the seed crystals grew at the expense of the matrix powder, a process known as templated grain growth. The degree of texture was analyzed using a variety of techniques including scanning electron microscopy, X-ray diffraction and electron backscatter diffraction. [source] Formation of Ceramics from Metakaolin-Based Geopolymers: Part I,Cs-Based GeopolymerJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2009Jonathan L. Bell The structural evolution and crystallization of a cesium-based geopolymer (Cs2O·Al2O3·4SiO2·11H2O) on heating was studied by a variety of techniques including X-ray diffraction, thermal analysis, dilatometry, pycnometry, specific surface area, and microstructural investigation. The Cs geopolymer gradually crystallized into pollucite (Cs2O·Al2O3·4SiO2) on heating above 900°C. Its low crystallization temperature is believed to be due to the presence of nuclei in the geopolymer precursor, which are formed after curing at 50°C for 24 h. The Cs-based geopolymer was found to be more refractory compared with K- and Na-based geopolymers. Significant shrinkage, due primarily to viscous sintering, did not occur until the samples were heated to above 1200°C. The microstructure of unheated geopolymer had ,20,30 nm-sized precipitates that coarsened on heating above 1000°C. By 1350°C, the geopolymer surface had a smooth, glassy texture, although large macropores and closed pores remained. After heating to 1600°C, the closed pores were removed, and the geopolymer reached ,98% of the theoretical density of pollucite. Higher than expected levels of Cs were found near large voids, as seen by scanning electron microscopy and transmission electron microscopy analysis. The presence of this extra Cs was due to Cs left behind in pore water, which was not bound within the geopolymer structure. [source] Solid-state NMR characterization of 69Ga and 71Ga in crystalline solidsMAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2006Jason T. Ash Abstract Gallium model systems containing four- and six-coordinate gallium sites have been investigated using solid-state NMR. Measurement of the isotropic chemical shift and electric field gradient (EFG) have been performed at 9.4 T on ,-Ga2O3, ,-Ga2O3, LiGaO2, NaGaO2, KGaO2, Ga2(SO4)3, and LaGaO3 using a variety of techniques on both NMR active nuclei (69Ga and 71Ga) including static, high speed magic-angle spinning (MAS), satellite transition (ST) spectroscopy, and rotor-assisted population transfer (RAPT). The chemical shift is found to correlate well with the coordination number, with four-coordinate gallium having values of approximately 50 ppm and six-coordinate gallium having values near 225 ppm (referenced to 1 M gallium nitrate solution). The magnitude of the EFG is found to be correlated to the distortion of the gallium polyhedra, with the strained systems having EFGs of 3 × 1021 Vm,2 or more, while the less strained systems have values of 1.5 × 1021 Vm,2 or less. A plot of chemical shift versus EFG suggests that solid-state NMR of gallium oxyanions can be more discriminating than liquid state NMR chemical shifts alone. Copyright © 2006 John Wiley & Sons, Ltd. [source] Experimental shock decomposition of siderite and the origin of magnetite in Martian meteorite ALH 84001METEORITICS & PLANETARY SCIENCE, Issue 6 2007M. S. BELL Naturally occurring siderite was first characterized by a variety of techniques to be sure that the starting material did not contain detectable magnetite. Samples were shocked in tungsten-alloy holders (W = 90%, Ni = 6%, Cu = 4%) to further ensure that any iron phases in the shock products were contributed by the siderite rather than the sample holder. Each sample was shocked to a specific pressure between 30 to 49 GPa. Transformation of siderite to magnetite as characterized by TEM was found in the 49 GPa shock experiment. Compositions of most magnetites are >50% Fe+2 in the octahedral site of the inverse spinel structure. Magnetites produced in shock experiments display the same range of sizes (,50,100 nm), compositions (100% magnetite to 80% magnetite-20% magnesioferrite), and morphologies (equant, elongated, euhedral to subhedral) as magnetites synthesized by Golden et al. (2001) and as the magnetites in Martian meteorite Allan Hills (ALH) 84001. Fritz et al. (2005) previously concluded that ALH 84001 experienced ,32 GPa pressure and a resultant thermal pulse of ,100,110°C. However, ALH 84001 contains evidence of local temperature excursions high enough to melt feldspar, pyroxene, and a silica-rich phase. This 49 GPa experiment demonstrates that magnetite can be produced by the shock decomposition of siderite as a result of local heating to > 470°C. Therefore, magnetite in the rims of carbonates in Martian meteorite ALH 84001 could be a product of shock devolatilization of siderite as well. [source] Stony meteorite porosities and densities: A review of the data through 2001METEORITICS & PLANETARY SCIENCE, Issue 8 2003D. T. Britt These data were taken from 925 samples of 454 different meteorites by a variety of techniques. Most meteorites have densities on the order of 3 to 4 g/cm3, with lower densities only for some volatile-rich carbonaceous meteorites and higher densities for stony irons. For the vast majority of stones, porosity data alone cannot distinguish between different meteorite compositions. Average porosities for most meteorite classes are around 10%, though individual samples can range as high as 30% porosity. Unbrecciated basaltic achondrites appear to be systematically less porous unless vesicles are present. The measured density of ordinary chondrites is strongly controlled by the amount of terrestrial weathering the sample has undergone with porosities steadily dropping with exposure to the terrestrial environment. A theoretical grain density based on composition can model "pre-weathered" porosities. The average model porosity for H and LL chondrites is 10%, while L chondrite model porosities average only 6%, a statistically significant difference. [source] Prognostic and predictive value of HER2/neu oncogene in breast cancerMICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2002Shahla Masood Abstract Assessment of HER2/neu oncogene has been used as both a prognostic and predictive marker for breast cancer. However, the choice of the best method to assess the status of HER2/neu oncogene in breast cancer tissue remains controversial. A variety of techniques are available to detect HER2/neu gene amplification and overexpression. Tissue-based detection methods by immunohistochemistry (IHC) and/or fluorescence in situ hybridization (FISH) offers a clear advantage over other approaches. FISH is a costly and relatively difficult assay and yet appears to be a better predictor of response to Herceptin® (Trastuzumab) therapy and patient outcome. IHC is less expensive and is easier to perform; however, it suffers from a high rate of false negativity and positivity as well as inter-observer variability among pathologists. Suggestions have been made to use IHC as a screening procedure followed by confirmation by FISH in selected cases. Considering the importance of an accurate assessment of HER2/neu oncogene in selecting therapy, a better alternative may be to use FISH as the primary testing for HER2/neu oncogene. Herceptin® therapy is associated with several side effects and is expensive. Thus, in the long term, it may be more cost-effective to use the FISH procedure and reduce the possibility of under-treatment or over-treatment of breast cancer patients. In addition, assessment of HER2/neu oncogene on every newly diagnosed early breast carcinoma may not be necessary. Metastatic lesions, when they occur, can be sampled by fine needle aspiration biopsy or core needle biopsy for assessment of HER2/Neu status. Microsc. Res. Tech. 59:102,108, 2002. © 2002 Wiley-Liss, Inc. [source] A single center comparison of one versus two venous anastomoses in 564 consecutive DIEP flaps: Investigating the effect on venous congestion and flap survival,MICROSURGERY, Issue 3 2010Morteza Enajat M.D. Background: Venous complications have been reported as the more frequently encountered vascular complications seen in the transfer of deep inferior epigastric artery (DIEA) perforator (DIEP) flaps, with a variety of techniques described for augmenting the venous drainage of these flaps to minimize venous congestion. The benefits of such techniques have not been shown to be of clinical benefit on a large scale due to the small number of cases in published series. Methods: A retrospective study of 564 consecutive DIEP flaps at a single institution was undertaken, comparing the prospective use of one venous anastomosis (273 cases) to two anastomoses (291 cases). The secondary donor vein comprised a second DIEA venae commitante in 7.9% of cases and a superficial inferior epigastric vein (SIEV) in 92.1%. Clinical outcomes were assessed, in particular rates of venous congestion. Results: The use of two venous anastomoses resulted in a significant reduction in the number of cases of venous congestion to zero (0 vs. 7, P = 0.006). All other outcomes were similar between groups. Notably, the use of a secondary vein did not result in any significant increase in operative time (385 minutes vs. 383 minutes, P = 0.57). Conclusions: The use of a secondary vein in the drainage of a DIEP flap can significantly reduce the incidence of venous congestion, with no detriment to complication rates. Consideration of incorporating both the superficial and deep venous systems is an approach that may further improve the venous drainage of the flap. © 2009 Wiley-Liss, Inc. Microsurgery, 2010. [source] Time-Resolved and Steady-State Fluorescence Spectroscopy of Eumelanin and Indolic PolymersPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2007Stephen P. Nighswander-Rempel Eumelanin plays a variety of important physiological roles in human skin. However, its structure and fundamental properties still remain poorly understood. Although the absorbance of eumelanin is broad and reveals little about its structure, a variety of techniques have revealed the presence of a disordered array of chromophores within the melanin compound. In order to examine the fluorescence decay dynamics of these chromophores, time-resolved spectroscopy was applied to solutions of synthetic eumelanin and a melanin-like polymer of N-methyl,5-hydroxy,6-methoxyindole (N-Me-5H6MI). Solutions were excited with 80 fs laser pulses at 355, 370, 390 and 400 nm, and decay time courses were acquired at 20 nm intervals between 400 and 600 nm for each excitation wavelength. Decay profiles for both eumelanin and the polymer exhibited a characteristic multiexponential behavior with decay times between 0.5 and 15 ns, although steady-state spectra for the polymer exhibited only two peaks. The long-decay component in the polymer showed a significant decrease in both amplitude (30,5%) and decay time (14,6 ns) with increasing emission wavelength. In contrast, the amplitude and decay time in melanin increased slightly (10,15% and 7,10 ns, respectively) from 400 to 520 nm emission, at which point they leveled off. These trends were consistent for all excitation wavelengths. These results suggest that the multiexponential behavior of melanin fluorescence is characteristic of each oligomer within the eumelanin compound, and is consistent with the assertion that the diversity of constituents within eumelanin provides it with a robustness in spectral properties. [source] Ion transport in roots: measurement of fluxes using ion-selective microelectrodes to characterize transporter functionPLANT CELL & ENVIRONMENT, Issue 1 2001I. A. Newman ABSTRACT The transport of mineral ions into and out of tissues and cells is central to the life of plants. Ion transport and the plasma membrane transporters themselves have been studied using a variety of techniques. In the last 15 years, measurement of specific ion fluxes has contributed to the characterization of transport systems. Progress in molecular genetics is allowing gene identification and controlled expression of transporter molecules. However the molecular expression of transporter gene products must be characterized at the functional level. The ion-selective microelectrode technique to measure specific ion fluxes non-invasively is ideally suited to this purpose. This technique, its theory, its links with others and its application and prospects in plant science, are discussed. Ions studied include hydrogen, potassium, sodium, ammonium, calcium, chloride and nitrate. Applications discussed include: solute ion uptake by roots; gravitropism and other processes in the root cap, meristematic and elongation zones; Nod factor effect on root hairs; osmotic and salt stresses; oscillations; the effects of light and temperature. Studies have included intact roots, leaf mesophyll and other tissues, protoplasts and bacterial biofilms. A multi-ion capability of the technique will greatly assist functional genomics, particularly when coupled with imaging techniques, patch clamping and the use of suitable mutants. [source] A synergistic approach to protein crystallization: Combination of a fixed-arm carrier with surface entropy reductionPROTEIN SCIENCE, Issue 5 2010Andrea F. Moon Abstract Protein crystallographers are often confronted with recalcitrant proteins not readily crystallizable, or which crystallize in problematic forms. A variety of techniques have been used to surmount such obstacles: crystallization using carrier proteins or antibody complexes, chemical modification, surface entropy reduction, proteolytic digestion, and additive screening. Here we present a synergistic approach for successful crystallization of proteins that do not form diffraction quality crystals using conventional methods. This approach combines favorable aspects of carrier-driven crystallization with surface entropy reduction. We have generated a series of maltose binding protein (MBP) fusion constructs containing different surface mutations designed to reduce surface entropy and encourage crystal lattice formation. The MBP advantageously increases protein expression and solubility, and provides a streamlined purification protocol. Using this technique, we have successfully solved the structures of three unrelated proteins that were previously unattainable. This crystallization technique represents a valuable rescue strategy for protein structure solution when conventional methods fail. [source] Persistence in some energy futures marketsTHE JOURNAL OF FUTURES MARKETS, Issue 5 2010Juncal Cunado In this study, we examine the possibility of long-range dependence in some energy futures markets for different maturities. In order to test for persistence, we use a variety of techniques based on non-parametric, semi-parametric and parametric methods. The results indicate that there is little or no evidence of long memory in gasoline, propane, oil and heating oil at different maturities. However, when we focus on the volatility process, proxied by the absolute returns, we find strong evidence of long memory in all the variables at different contracts. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 30:490,507, 2010 [source] Fast track surgery: A clinical auditAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 2 2010Jonathan CARTER Background:, Fast track surgery is a concept that utilises a variety of techniques to reduce the surgical stress response, allowing a shortened length of stay, improved outcomes and decreased time to full recovery. Aims:, To evaluate a peri-operative Fast Track Surgical Protocol (FTSP) in patients referred for abdominal surgery. Methods:, All patients undergoing a laparotomy over a 12-month period were entered prospectively on a clinical database. Data were retrospectively analysed. Results:, Over the study period, 72 patients underwent a laparotomy. Average patient age was 54 years and average weight and BMI were 67.2 kg and 26 respectively. Sixty three (88%) patients had a vertical midline incision (VMI). There were no intraoperative blood transfusions. The median length of stay (LOS) was 3.0 days. Thirty eight patients (53%) were discharged on or before post op day 3, seven (10%) of whom were discharged on postoperative day 2. On stepwise regression analysis, the following were found to be independently associated with reduced LOS: able to tolerate early enteral nutrition, good performance status, use of COX inhibitor and transverse incision. In comparison with colleagues at the SGOG not undertaking FTS for their patients, the authors' LOS was lower and the RANZCOG modified Quality Indicators (QI's) did not demonstrate excess morbidity. Conclusions:, Patients undergoing fast track surgery can be discharged from hospital with a reduced LOS, without an increased readmission rate and with comparative outcomes to non-fast tracked patients. [source] Advances in Cell Culture Process Development: Tools and Techniques for Improving Cell Line Development and Process OptimizationBIOTECHNOLOGY PROGRESS, Issue 3 2008Susan T. Sharfstein At the 234th National Meeting of the American Chemical Society, held in Boston, MA, August 19,23, 2007, the ACS BIOT division held two oral sessions on Cell Culture Process Development. In addition, a number of posters were presented in this area. The critical issues facing cell culture process development today are how to effectively respond to the increase in product demands and decreased process timelines while maintaining robust process performance and product quality and responding to the Quality by Design initiative promulgated by the Food and Drug Administration. Two main areas were addressed in the presentations: first, to understand the effects of process conditions on productivity and product quality, and second, to achieve improved production cell lines. A variety of techniques to achieve these goals were presented, including automated flow cytometric analysis, a high-throughput cell analysis and selection method, transcriptional and epigenetic techniques for analysis of cell lines and cell culture systems, and novel techniques for glycoform analysis. [source] | |||||||||||||||||||||||||