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Selected AbstractsAnalysis of the gutta-percha filled area in C-shaped mandibular molars obturated with a modified MicroSeal techniqueINTERNATIONAL ENDODONTIC JOURNAL, Issue 3 2009R. Ordinola-Zapata Abstract Aim, To analyse the gutta-percha filled area of C-shaped molar teeth root filled with the modified MicroSeal technique with reference to the radiographic features and the C-shaped canal configuration. Methodology, Twenty-three mandibular second molar teeth with C-shaped roots were classified according to their radiographic features as: type I , merging, type II , symmetrical and type III , asymmetrical. The canals were root filled using a modified technique of the MicroSeal system. Horizontal sections at intervals of 600 ,m were made 1 mm from the apex to the subpulpal floor level. The percentage of gutta-percha area from the apical, middle and coronal levels of the radiographic types was analysed using the Kruskal,Wallis test. Complementary analysis of the C-shaped canal configurations (C1, C2 and C3) determined from cross-sections from the apical third was performed in a similar way. Results, No significant differences were found between the radiographic types in terms of the percentage of gutta-percha area at any level (P > 0.05): apical third, type I: 77.04%, II: 70.48% and III: 77.13%, middle third, type I: 95.72%, II: 93.17%, III: 91.13% and coronal level, type I: 98.30%, II: 98.25%, III: 97.14%. Overall, the percentage of the filling material was lower in the apical third (P < 0.05). No significant differences were found between the C-shaped canal configurations apically; C1: 72.64%, C2: 79.62%, C3: 73.51% (P > 0.05). Conclusions, The percentage of area filled with gutta-percha was similar in the three radiographic types and canal configuration categories of C-shaped molars. These results show the difficulty of achieving predictable filling of the root canal system when this anatomical variation exists. In general, the apical third was less completely filled. [source] An evaluation of .06 tapered gutta-percha cones for filling of .06 taper prepared curved root canalsINTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2005M. P. J. Gordon Abstract Aim, To compare the area occupied by gutta-percha, sealer, or void in standardized .06 tapered prepared simulated curved canals and in mesio-buccal canals of extracted maxillary first molars filled with a single .06 gutta-percha point and sealer or lateral condensation of multiple .02 gutta-percha points and sealer. Methodology, Simulated canals in resin blocks with either a 30° curve and radius of 10.5 mm (n = 20) or a 58° curve and 4.7 mm radius (n = 20) and curved mesio-buccal canals of extracted maxillary first molars (n = 20) were prepared using .06 ProFiles® in a variable tip crown-down sequence to an apical size 35 at 0.5 mm from the canal terminus or apical foramen. Ten 30° and 58° curved resin canals and 10 canals in the extracted teeth group were obturated with .02 taper gutta-percha cones and AH 26 sealer using lateral condensation. The time required to obturate was recorded. The remaining canals were obturated with a single .06 taper gutta-percha cone and AH 26 sealer. Excess gutta-percha was removed from the specimens using heat and the warm mass vertically condensed. Horizontal sections were cut at 0.5, 1.5, 2.5, 4.5, 7.5 and 11.5 mm from the canal terminus or apical foramen. Colour photographs were taken using an Olympus 35 mm camera attached to a stereomicroscope set at ×40 magnification, and then digitized using a flatbed scanner. The cross-sectional area of the canal contents was analysed using Adobe PhotoShop®. The percentage of gutta-percha, sealer or voids to the total root canal area were derived and data analysed using unpaired Student's t -test and the Mann,Whitney U -test. Results, In the 30° curved canals the levels had between 94 and 100% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone techniques. In the 58° curved canals the levels had 92,99% of the area filled with gutta-percha, with the single cone technique having significantly (P < 0.05) more gutta-percha fill at the 2.5 mm level only. In the mesio-buccal canals of the teeth the levels had between 72 and 96% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone technique. The time for obturation was significantly (P < 0.05) greater for lateral condensation compared with the single cone technique in all groups. Conclusions, The .06 taper single cone technique was comparable with lateral condensation in the amount of gutta-percha occupying a prepared .06 tapered canal. The .06 single cone technique was faster than lateral condensation. [source] Percentage of filled canal area in mandibular molars after conventional root-canal instrumentation and after a noninstrumentation technique (NIT)INTERNATIONAL ENDODONTIC JOURNAL, Issue 9 2003C. N. Ardila Abstract Aim, To compare the percentage of filled canal area in mandibular molar roots after using conventional root-canal hand instrumentation or after a noninstrumentation technique (NIT). Methodology, Forty mandibular molars were used shortly after extraction. The root canals of 20 molars in the manual group were conventionally prepared using hand instruments and then filled with warm vertical compaction of gutta-percha. The 20 teeth in the second group were cleaned and obturated by NIT. In each case, the entire molar, including the crown and the roots, was embedded in an acrylic resin cylinder before NIT. Horizontal sections were cut at 2, 4, 6 and 8 mm from the apex. Images of the sections were taken using a microscope at ×40 magnification and a digital camera; the images were scanned as Tagged Image File Format (TIFF) images into a PC. The cross-sectional area of the canal with the filling materials was measured using an image analysis programme. The percentage of filled area was calculated. The difference in the percentage of filled canal area between the two groups was analysed using a Student's t -test. Results, At all levels, 93,100% of the canal area was filled in both groups. No significant difference was found between the manual technique and the NIT technique at any level (P > 0.05). Conclusions, Within the limitations of this study, following the cleaning and filling of root canals using NIT, the percentage of filled root canal was similar to that using warm vertical compaction of gutta-percha after conventional root-canal instrumentation. [source] Chronic telogen effluvium or early androgenetic alopecia?INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 11 2004Rodney Sinclair MBBS A 16-year-old girl presented with a 12-month history of generalized hair shedding from the scalp. The onset of shedding coincided with the development of Hashimoto's thyroiditis and iron deficiency. At the time of initial presentation, the Hashimoto's thyroiditis had been treated with Neo-Mercazole and she was euthyroid. Her iron stores were low, with a ferritin level of 13 µg/L. As she was vegetarian, oral iron replacement therapy was commenced without further investigation. On follow-up 6 months later, her iron stores were normal (ferritin, 36 µg/L), but the hair shedding had continued. On examination, there was a positive hair pull test from both the vertex of the scalp and the occipital scalp. There was mild bitemporal recession, but no widening of the central part, and she appeared to have a full, thick head of hair (Fig. 1). Additional investigations at that time revealed normal thyroid function and negative antinuclear antibody (ANA) and syphilis serology. She was on no medication other than Neo-Mercazole. Serum testosterone, dihydroepiandosterone sulphate (DHEAS) and sex hormone binding globulin (SHBG) were normal. Two 4-mm punch biopsies were taken from the vertex of the scalp; one was sectioned horizontally and the other vertically. The vertical section was unremarkable. On the horizontal section, there were 32 hair follicles in total, 30 of which were terminal hairs and two of which were vellus hairs. One hair was in telogen. The ratio of terminal to vellus hairs was 15 : 1. Figure 1. Initial presentation A diagnosis of chronic telogen effluvium was made. The condition was explained to the patient and she was reassured that chronic telogen effluvium is not a progressive condition and does not lead to baldness. No treatment was recommended. At follow-up 12 months later, the hair loss had obviously progressed and the patient was assessed as having Ludwig Stage 1 androgenetic alopecia with widening of the central part (Fig. 2). Repeat blood tests showed normal iron studies, thyroid function, and hormone parameters. Three 4-mm punch biopsies were taken from the vertex of the scalp and all were sectioned horizontally. The terminal to vellus hair ratios were 1 : 1, 2.6 : 1, and 1.9 : 1. A diagnosis of androgenetic alopecia was made and she was commenced on oral spironolactone, 200 mg/day. Figure 2. Presentation after 12 months [source] Lateral inhibition in the astogeny of conical multistiped graptolitesLETHAIA, Issue 1 2000Øyvind Hammer Conical multistiped graptolites (in particular Rhabdinopora) grow in patterns which can be understood using a lateral inhibition model based on diffusion of nutrients or pheromones around the colony. Many aspects of rhabdosome morphology are explained with this model. These include branching and the distribution of branching points, the morphology of bifurcations, the almost constant spacing of stipes, the high rate of branching in early stages, the variation in expansion rate, and regeneration patterns after damage. For the first time, a full three-dimensional computer simulation of graptolite growth has been accomplished, assuming biologically justified processes instead of formal growth rules. The simulations indicate that dissepiments were instrumental in controlling rhabdosome shape, but not sufficient to keep its horizontal section perfectly circular. [source] Advanced Statistical Analysis as a Novel Tool to Pneumatic Conveying Monitoring and Control Strategy DevelopmentPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 3-4 2006Andrzej Romanowski Abstract Behaviour of powder flow in pneumatic conveying has been investigated for many years, though it still remains a challenging task both practically and theoretically, especially when considering monitoring and control issues. Better understanding of the gas-solids flow structures can be beneficial for the design and operation of pneumatic transport installations. This paper covers a novel approach for providing the quantitative description in terms of parameter values useful for monitoring and control of this process with the use of Electrical Capacitance Tomography (ECT). The use of Bayesian statistics for analysis of ECT data allows the direct estimation of control parameters. This paper presents how this characteristic parameters estimation can be accomplished without the need for reconstruction and image post processing, which was a classical endeavour whenever tomography was applied. It is achieved using a ,high-level' statistical Bayesian modelling combined with a Markov chain Monte Carlo (MCMC) sampling algorithm. Advanced statistics is applied to data analysis for measurements coming from the part of phenomena present in the horizontal section of pneumatic conveyor during slug formation. [source] The histopathology of alopecia areata in vertical and horizontal sectionsDERMATOLOGIC THERAPY, Issue 4 2001David A. Whiting Alopecia areata (AA) is a relatively common disease affecting 1.7% of Americans by the age of 50 years. The diagnosis is usually made on clinical grounds. In some cases the diagnosis is elusive and biopsies are necessary. In other cases biopsies are useful from a prognostic point of view to determine whether there are enough follicles left for possible future regrowth. In view of the active research being conducted into AA, biopsies provide valuable material for further investigation. The diagnosis of AA is improved by the use of horizontal sections in addition to or instead of vertical sections of scalp biopsies. The histopathologic features favoring the diagnosis of AA include peribulbar and intrabulbar mononuclear infiltrates, degenerative changes in the hair matrix, decreased numbers of terminal anagen follicles, increased numbers of terminal catagen and telogen follicles, an increased number of follicular stelae, an increased number of miniaturized vellus hair follicles, and pigment incontinence of hair bulbs and follicular stelae. Follicular counts with horizontal sections are particularly helpful in making the diagnosis of AA when the biopsy has been taken between acute episodes and the characteristic peribulbar inflammatory infiltrate is absent. [source] The use of periphytic diatoms as a means of assessing impacts of point source inorganic nutrient pollution in south-eastern AustraliaFRESHWATER BIOLOGY, Issue 5 2006JOCELYN DELA-CRUZ Summary 1. Periphytic diatoms are used as indicators of water quality because their ecological tolerances or preferences to environmental variables are thought to be predictable. However, much of the present autecological information for periphytic diatoms has been derived from studies conducted in the northern hemisphere. In this present study we used periphytic diatoms to determine the impacts of inorganic nutrient pollution in a tidal river system in the temperate latitudes of south-east Australia. In so doing, we assess the suitability of the use of the ,northern hemisphere' ecological tolerance/preference data for periphytic diatoms. 2. Artificial substrates were used to collect periphytic diatoms at 35 sites, which were positioned along the riverbanks and the middle of the river at various distances upstream and downstream of the sewage outfall. The sampling design took into account tidal excursions and the observed sewage plume dynamics. Periphytic diatoms were collected during the austral winter month of August and the austral spring months of September and October. We deployed the artificial substrates for 4 weeks to allow the periphytic diatoms to recruit and colonise, before identifying and enumerating the assemblages. 3. Data analysis included two approaches: multivariate visualisations of combinations of environmental and biological data to investigate shifts in species structure of the periphytic diatom assemblage and multimetric indices based on ecological tolerance/preference data. 4. We found that the spatial patterns inferred from multivariate and multimetric analyses were consistent. Temporal variation in the composition of the periphytic diatom assemblage was greater than the spatial variation along horizontal sections of the river (in any one deployment) due mainly to shifts between winter and spring species. 5. Outfall effects were most apparent in winter, possibly because subsequent deployments were swamped by growth of spring periphytic diatoms. The outfall effects included a shift towards pollutant tolerant species and a reduction in the variability of the periphytic diatom assemblage across the river. 6. We conclude that the use of periphytic diatoms and associated ecological tolerance/preference data as a means of assessing impacts of point source inorganic nutrient pollution is effective. An understanding of river and sewage flow patterns is essential to the design of appropriate monitoring programmes and to the interpretation of results, especially as periphytic diatoms are sensitive to many environmental variables. [source] Extractive bioconversion in a four-phase external-loop airlift bioreactorAICHE JOURNAL, Issue 7 2000Lidija Sajc The integration of biosynthesis and product separation can increase the productivity of immobilized plant cells in airlift bioreactors. Extractive bioconversion of anthraquinones was studied in an external-loop airlift bioreactor consisting of a riser, a downcomer, and two horizontal sections, while containing alginate-immobilized Frangula alnus cells, a continuous aqueous phase (nutrient solution), dispersed solvent phase (n-hexadecane or silicone oil), and gas bubbles. A simple mathematical model was developed to describe the cocurrent liquid-liquid extraction in the riser section of the bioreactor and to rationalize the measured product concentrations in the aqueous and solvent phase. The model equations were solved analytically in a dimensionless form and used to study the effects of flow conditions, solvent properties, product formation rate, droplet size, and contactor length on the extraction efficiency and product concentration profiles in the continuous and dispersed phase. [source] Distribution of prospective glutamatergic, glycinergic, and GABAergic neurons in embryonic and larval zebrafishTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2004Shin-Ichi Higashijima Abstract Zebrafish are an excellent model for studies of the functional organization of neuronal circuits, but little is known regarding the transmitter phenotypes of the neurons in their nervous system. We examined the distribution in spinal cord and hindbrain of neurons expressing markers of transmitter phenotype, including the vesicular glutamate transporter (VGLUT) genes for glutamatergic neurons, the neuronal glycine transporter (GLYT2) for glycinergic neurons, and glutamic acid decarboxylase (GAD65/67) for GABAergic neurons. All three markers were expressed in a large domain in the dorsal two-thirds of spinal cord, with additional, more ventral expression domains for VGLUT2 and GAD/GABA. In the large dorsal domain, dual in situ staining showed that GLYT2 -positive cells were intermingled with VGLUT2 cells, with no dual-stained neurons. Many of the neurons in the dorsal expression domain that were positive for GABA markers at embryonic stages were also positive for GLYT2, suggesting that the cells might use both GABA and glycine, at least early in their development. The intermingling of neurons expressing inhibitory and excitatory markers in spinal cord contrasted markedly with the organization in hindbrain, where neurons expressing a particular marker were clustered together to form stripes that were visible running from rostral to caudal in horizontal sections and from dorsomedial to ventrolateral in cross sections. Dual labeling showed that the stripes of neurons labeled with one transmitter marker alternated with stripes of cells labeled for the other transmitter phenotypes. The differences in the distribution of excitatory and inhibitory neurons in spinal cord versus hindbrain may be tied to differences in their patterns of development and functional organization. J. Comp. Neurol. 480:1,18, 2004. © 2004 Wiley-Liss, Inc. [source] | |||||||||||||