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Cavity Size (cavity + size)
Selected AbstractsRestoration removal with and without the aid of magnificationJOURNAL OF ORAL REHABILITATION, Issue 4 2001A. H. Forgie This study aims to quantify any cavity size change following removal of tooth-coloured restorations in vitro using unaided vision and 2·6× magnification. Occlusal composite restorations were removed under simulated clinical conditions and changes in cavity size were measured, blind to method, using standardized photographs. The outline of the cavity was digitized and its area was used as a surrogate for cavity size. The change in cavity size was determined for unaided vision and 2·6× magnification, with any differences between the techniques investigated. There were significant increases in cavity size using both techniques and although the increase in size was less when magnification was used, the difference was not statistically significant. Cavity size changes significantly during re-restoration and the use of magnification may be of benefit for some clinicians in reducing the size of the change. [source] Fatty acid metabolism assessed by 125I-iodophenyl 9-methylpentadecanoic acid (9MPA) and expression of fatty acid utilization enzymes in volume-overloaded heartsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2004T. Miyamoto Abstract Background, The peroxisome proliferator-activated receptor (PPAR) , is a member of the nuclear receptor superfamily and regulates gene expression of fatty acid utilization enzymes. In cardiac hypertrophy and heart failure by pressure-overload, myocardial energy utilization reverts to the fetal pattern, and metabolic substrate switches from fatty acid to glucose. However, myocardial metabolism in volume-overloaded hearts has not been rigorously studied. The aim of the present study was to examine fatty acid metabolism and protein expressions of PPAR, and fatty acid oxidation enzymes in volume-overloaded rabbit hearts. Methods, Volume-overload was induced by carotid-jugular shunt formation. Sham-operated rabbits were used as control. Chronic volume-overload increased left ventricular weight and ventricular cavity size, and relative wall thickness was decreased, indicating eccentric cardiac hypertrophy. 125I-iodophenyl 9-methylpentadecanoic acid (9MPA) was intravenously administered, and animals were sacrificed at 5 min after injection. The 9MPA was rapidly metabolized to iodophenyl-3-methylnonanoic acid (3MNA) by ,-oxidation. Lipid extraction from the myocardium was performed by the Folch method, and radioactivity distribution of metabolites was assayed by thin-layer chromatography. The protein was extracted from the left ventricular myocardium, and levels of PPAR, and fatty acid oxidation enzymes were examined by Western blotting. Results, Myocardial distribution of 9MPA tended to be more heterogeneous in shunt than in sham rabbits (P = 0·06). In volume-overloaded hearts by shunt, the conversion from 9MPA to 3MNA by ,-oxidation was faster than the sham-control hearts (P < 0·05). However, protein levels of PPAR, and fatty acid utilization enzymes were unchanged in shunt rabbits compared with sham rabbits. Conclusions, These data suggest that myocardial fatty acid metabolism is enhanced in eccentric cardiac hypertrophy by volume-overload without changes in protein expressions of PPAR, and fatty acid utilization enzymes. Our data may provide a novel insight into the subcellular mechanisms for the pathological process of cardiac remodelling in response to mechanical stimuli. [source] Synthesis and metal transport ability of a new series of thiamacrocycles containing thiol and disulfide groups inside the ringHETEROATOM CHEMISTRY, Issue 4 2001Tatsuya Nabeshima Synthetic methods for thiamacrocycles containing two thiol groups or a disulfide linkage and their abilities to effect single heavy-metal-ion transport across a liquid membrane were examined. High Ag+ selectivity was accomplished by the thiol or disulfide hosts, although all the corresponding crown ether analogs bearing a disulfide group showed no Ag+ selectivity. The difference of the transport preferences among the thiacrown ethers prepared here is considered to be reflected by the position and the number of the sulfur atoms ligating to Ag+ and the cavity size of the hosts. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:276,281, 2001 [source] Reorganization of highly preorganized hosts upon cation complexation: Ab initio study of fluorospherandsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4 2007Shabaan A. K. Elroby Abstract Fluorospherands (F-spherands) are highly preorganized hosts composed of fluorobenzene or 4-methylfluorobenzene units attached to one another at their 2,6-positions. To understand the intrinsic factors affecting cation complexation, we investigated the complexation behavior between F-spherands and cations using density functional theory (DFT) at the level of B3LYP/6-31G**. The F6-spherand (C6H3F)6, (1) has a highly preorganized spherical cavity, which can encapsulate Li+ and Na+. Its cavity is not big enough for K+ and NH, which prefer external binding. Plausible conformations were studied for F8-spherand (C6H3F)8. Conformer of D2d symmetry (2b) is more stable than that of D4d (2a), in agreement with NMR experiments. The cavity size of F8-spherand is big enough to encapsulate all cations studied. However, the cavity size of 2b is smaller than that of 2a, which resulted in the guest selectivity. Upon complexation, 2b conformation is more stable for Li+ and Na+, while 2a conformation is preferred for larger cations such as K+ and NH. Thus, the ab initio calculations over these highly preorganized fluorospherands give important insights into their host,guest chemistry. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source] Natural bone collagen scaffold combined with OP-1 for bone formation induction in vivoJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Yu Qian Abstract The scaffold is a key element to osteogenic tissue engineering as it provides a microenvironment for bone formation. Natural bone collagen scaffold (NBCS) is a novel biomaterial scaffold acid-extracted from organic human bone. The objective of this study was to characterize NBCS and evaluate the osteoconductivity of the scaffold, in combination with osteogenic protein-1 (OP-1), using a rabbit posteolateral lumbar fusion model. Thirty two rabbits were divided into 4 experimental groups, autograft, NBCS alone, OP-1 alone or NBCS combined with OP-1. Bone formation was evaluated by micro-CT, quantitative histological analysis, immunohistochemistry and semi-quantitative RT-PCR at 6 weeks postoperatively. By scanning electronic microscope, we showed that NBCS maintains a porous, interconnecting microarchitecture. Micro-CT analysis demonstrated that NBCS combined with OP-1 significantly induced (p < 0.01) bone formation at the fusion site as compared to control groups. This was confirmed by quantitative histological analysis which demonstrated that the NBCS combined with OP-1 significantly enhanced bone matrix area (17.7 mm2) (p < 0.05) and bone marrow cavity size (71.3 mm2) (p < 0.05) as compared to the controls. Immunohistochemical assessment and RT-PCR also demonstrated that NBCS combined with OP-1 enhanced type I collagen and osteonectin expression. Together, these results suggest that NBCS is an effective scaffold for osteogenesis, and combined with growth factors such as OP-1, possesses both osteoconductive and osteoinductive properties that are sufficient for bone regeneration. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Restoration removal with and without the aid of magnificationJOURNAL OF ORAL REHABILITATION, Issue 4 2001A. H. Forgie This study aims to quantify any cavity size change following removal of tooth-coloured restorations in vitro using unaided vision and 2·6× magnification. Occlusal composite restorations were removed under simulated clinical conditions and changes in cavity size were measured, blind to method, using standardized photographs. The outline of the cavity was digitized and its area was used as a surrogate for cavity size. The change in cavity size was determined for unaided vision and 2·6× magnification, with any differences between the techniques investigated. There were significant increases in cavity size using both techniques and although the increase in size was less when magnification was used, the difference was not statistically significant. Cavity size changes significantly during re-restoration and the use of magnification may be of benefit for some clinicians in reducing the size of the change. [source] Para -halogenated benzaldehyde molecules included in cyclodextrins: a combined spectroscopic and thermal analysisJOURNAL OF RAMAN SPECTROSCOPY, Issue 4 2006Paulo J. A. Ribeiro-Claro Abstract The inclusion complexes of 4-X-benzaldehyde guests (X = F, Cl, Br) in ,-, ,-and ,-cyclodextrins (,CD, ,CD and ,CD) were prepared and characterized by means of thermogravimetry, differential scanning calorimetry (DSC) and vibrational spectroscopy. The stoichiometry of the inclusion complexes ranges from 2:1 to 1:2, depending on the cavity size of the host. Sensitive vibrational modes such as CO and ring CH stretching modes were used to monitor the effects of the inclusion process and to assess the preferred inclusion geometry for each host-guest pair. On the whole, the spectral observations suggest that the small ,CD cavity imposes important structural restrictions on the guest molecule, while the larger ,CD cavity allows ,liquid-type' intermolecular contacts. Copyright © 2005 John Wiley & Sons, Ltd. [source] Opal Gels Templated Synthesis of Structured Titania Materials,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 20 2004Jianhua Rong Abstract Summary: Core/shell opal gels of sulfonated polystyrene were used as templates to synthesize structured crystalline titania materials. Under acidic conditions, opal materials with hollow spheres of controllable shell thickness and cavity size were prepared. Under neutral conditions, inverse opal inorganic materials with a tunable pore size were prepared. It is crucial that proton ions induce a preferential sol/gel process, forming titania in the gel. Scanning electron micrograph of the interior region of a structured titania material derived from the G1 template used here. The inset shows broken spheres in which the internal cavity can be observed. [source] Clinal variation of maxillary sinus volume in Japanese macaques (Macaca fuscata)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2003Todd C. Rae Abstract Macaques (genus Macaca) are unique among cercopithecids in that they possess a maxillary sinus, and among anthropoids in that they demonstrate a relatively weak relationship between the size of this sinus and the cranium. To test the hypothesis that extrinsic factors may contribute to maxillary sinus size variation, a sample of 46 Japanese macaque (M. fuscata) crania from known localities were subjected to computed tomography (CT) imaging, and sinus volume and nasal cavity area were analyzed relative to latitude and temperature variables. The results suggest that the environmental factors are significant determinants of nasal cavity size in Japanese macaques, but that the relationships between the environment and maxillary sinus volume (MSV) are probably a passive consequence of changes in the size of the nasal cavity. The sinus shrinks as the nasal cavity expands, due to an increased need to condition inspired air in colder climates. This in turn suggests that the sinus itself does not contribute significantly to upper respiratory function. Am. J. Primatol. 59:153,158, 2003. © 2003 Wiley-Liss, Inc. [source] Static bone cavity in the condylar neck and mandibular notch of the mandibleAUSTRALIAN DENTAL JOURNAL, Issue 1 2009K Minowa Abstract This study presents the radiographic findings of two cases of static bone cavity in the inferior aspect of the condylar neck and mandibular notch of the mandible. On plain CT, a soft tissue mass was observed in each cavity. The submandibular gland and the other glands were not found in each cavity. On contrast-enhanced CT, the soft tissue in the cavity in the inferior aspect of the condylar neck had marked linear enhancement and dilated vasculature structure was observed in the cavity. On the contrast-enhanced MRI, the soft tissue in the cavity of the mandibular notch had marked enhancement and flow void was detected in the cavity. In the inferior aspect of the condylar neck, the cavity size had enlarged radiographically over a period of three years. Vascular lesions were found in the cavity located in the inferior aspect of the condylar neck and mandibular notch of the mandible by both CT and MRI. The vascular lesion might explain the enlargement of the static bone cavity. [source] Positron Annihilation Lifetimes in Cucurbiturils: Evidence of Internal Inclusion of Gold in CB[7]CHEMPHYSCHEM, Issue 5 2009Pedro Montes-Navajas Abstract Positron lifetime spectroscopy serves to determine the void volumes of cucurbituril (CB) capsules, which are not amenable to standard gas adsorption methods. In the case of the host,guest complex Au§CB[7], it also provides evidence of the inclusion of gold nanoparticles in the CB cavity (see space-filling model; Au golden, C gray, H cyan, N blue, O red). Positron annihilation lifetime (PAL) measurements are carried out to determine the cavity dimensions of hydrated and dehydrated cucurbiturils (CB[n]; n=5,6,7,8). In the case of hydrated samples, the dimensions of the cavity are unrelated to the number of glycoluril units of the CB, whereas for dehydrated samples the cavity dimensions measured by PAL follow the expected order, although the experimental values obtained by PAL are significantly smaller than the dimensions of each CB determined by crystallography. For a host,guest complex in which colloidal gold nanoparticles are assumed to be included inside CB[7], a significant reduction of the cavity size is measured. This represents an experimental evidence of the inclusion of gold inside CB[7], which complements previous high-resolution transmission electron microscopy (TEM) images. [source] Guest-Inclusion Behavior of Double-Strand 1D Coordination Polymers Based on N,N, -Type Schiff Base LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2008Qing Wang Abstract Four double-strand one-dimensional (1D) coordinationpolymers, namely, {[Ni(N3Py)2(NO3)2]·(C6H6)x·C2H5OH}n (1), [Cd(ImBNN)2(CH3C6H4SO3)2]n (2), {[Co(N3OPy)2(H2O)2](ClO4)2·C6H6·H2O}n (3), and {[Co(N3OPy)2(H2O)2](ClO4)2·(C8H10)x}n (4) were obtained from the assembly of three N,N, -type Schiff base ligands, 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (N3Py), 2,5-bis(4,-(imidazol-1-yl)benzyl)-3,4-diaza-2,4-hexadiene (ImBNN), and bis[4-(3-pyridylmethylenemino)phenoxy]methane (N3OPy), with transition-metal ions. All complexes were characterized by single-crystal X-ray diffraction, X-ray powder diffraction, and FTIR measurements. The guest-inclusion behavior of these complexes were investigated by thermogravimetric and X-ray powder diffraction analyses. The structural relationship between the ligands and the cavity sizes and packing fashions have been discussed to elucidate the distinctive guest-inclusion behavior of these complexes.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Configurational Isomers of a Stilbene-Linked Bis(porphyrin) Tweezer: Synthesis and Fullerene-Binding StudiesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 35 2009Maher Fathalla Abstract A new stilbene-tethered bis(porphyrin) tweezer 5 has been synthesized through a Sonogashira cross-coupling reaction. The tweezer exists as two configurational isomers [(Z) + (E)], which have distinct cavity sizes. Fullerene-binding studies show that the (Z) isomer of the tweezer has a significantly higher affinity toward both C60 and C70 compared to the (E) congener. In addition, the (Z) , (E) photoisomerization of tweezer 5 is also discussed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] The first structure of a cold-adapted superoxide dismutase (SOD): biochemical and structural characterization of iron SOD from Aliivibrio salmonicidaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2009Hege Lynum Pedersen Superoxide dismutases (SODs) are metalloenzymes that catalyse the dismutation of the superoxide radical anion into O2 and H2O2 in a two-step reaction. The crystal structure of the iron superoxide dismutase from the cold-adapted and fish-pathogenic bacterium Aliivibrio salmonicida (asFeSOD) has been determined and refined to 1.7,Å resolution. The protein has been characterized and compared with the closely related homologous iron superoxide dismutase from the mesophilic Escherichia coli (ecFeSOD) in an attempt to rationalize its environmental adaptation. ecFeSOD shares 75% identity with asFeSOD. Compared with the mesophilic FeSOD, the psychrophilic FeSOD has distinct temperature differences in residual activity and thermostability that do not seem to be related to structural differences such as intramolecular or intermolecular ion bonds, hydrogen bonds or cavity sizes. However, an increased net negative charge on the surface of asFeSOD may explain its lower thermostability compared with ecFeSOD. Activity measurements and differential scanning calorimetry measurements revealed that the psychrophilic asFeSOD had a thermostability that was significantly higher than the optimal growth temperature of the host organism. [source] | ||||||||||||||||