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1.
Folia Morphol (Warsz) ; 81(2): 493-502, 2022.
Article in English | MEDLINE | ID: mdl-33634835

ABSTRACT

BACKGROUND: The incidence of an elongated styloid process (SP) and average length and diameter of SP have not been reported using Japanese cadavers. Data on the female-to-male ratio of an elongated SP vary. We calculated the average length and diameter of SP in Japanese cadavers and compared SP lengths between sexes. MATERIALS AND METHODS: Twenty-seven sides (right and left of bodies) in males and 51 sides in females were analysed. Measurements were obtained from the inferior external acoustic meatus to the distal tip of the SP. SP diameters at the proximal base, midpoint, and distal tip were measured. SP > 30 mm was considered elongated. We used Welch's t-test for the statistical analysis. Fisher's exact two-tailed test was also performed to analyse the female-to-male elongation ratio. A p-value < 0.05 was considered statistically significant. RESULTS: Styloid process elongation prevalence was 29.5% in our sample. The average full length was 27.04 ± 7.88 mm overall; the average diameters were 5.41 ± 1.77 mm at the proximal base and 2.21 ± 1.22 mm at the distal tip. The average SP measurement was 26.81 ± 5.92 mm in males and 27.16 ± 8.79 mm in females (p = 0.74). The female-to-male ratio of SP elongation was 1:2 (p = 0.041). Females had longer full lengths of non-elongated SPs than males (p = 0.004). Males had wider diameters at the proximal base of elongated SPs than females (p = 0.017). CONCLUSIONS: The average length of SP was 27.04 mm in the Japanese population and about 30% of the Japanese presented SP ≥ 30 mm. Male had significantly higher rate than female among the SP ≥ 30 mm, and female had significantly longer SPs than male among the SP < 30 mm. Anatomically, the SP gets narrow as distally goes. Our anatomical findings would be beneficial to creating treatment plans, diagnosis, and surgery.


Subject(s)
Ossification, Heterotopic , Temporal Bone , Cadaver , Female , Humans , Japan , Male , Temporal Bone/abnormalities , Temporal Bone/anatomy & histology
2.
Folia Morphol (Warsz) ; 80(2): 324-330, 2021.
Article in English | MEDLINE | ID: mdl-32488854

ABSTRACT

BACKGROUND: A gonadal artery originates as a branch of the abdominal aorta and renal artery inferior to the level of origin of the renal arteries. Variations in multiple right testicular arteries (RTAs) arising from the abdominal aorta are common. We aimed to re-evaluate the unusual courses of gonadal arteries with a single common trunk in relation to the inferior vena cava and left renal vein and explain the developmental anatomy. MATERIALS AND METHODS: The observational cross-sectional study was performed on 54 Japanese adult cadavers (29 men and 25 women). We examined the literature and developed embryological hypotheses on the single common trunk of the gonadal artery. RESULTS: The gonadal artery, testicular artery, and ovarian artery arose from the abdominal aorta in 93.1%, 96.3%, and 89.6% of cases, respectively, and from the renal artery in 4.9%, 3.7%, and 6.3% of cases, respectively. We found two rare variations in the RTAs observed during the routine dissection of two male cadavers; in these two cases, a single common trunk of the RTAs originated from the abdominal aorta. A single common trunk was found in 3.7% of cadavers, 2.0% of sides, and 2.0% of arteries in the gonadal artery and in 6.9% of cadavers, 3.8% of sides, and 3.7% of arteries in the testicular artery. All cases of the single common trunk, including those in past reports, were observed only in men. CONCLUSIONS: Knowledge of the variations in RTAs has important clinical consequences for invasive and non-invasive arterial procedures. In addition, this variation provides a new interpretation of the embryology of the gonadal artery. Variations similar to our findings have not been previously reported. Therefore, different variations concerning the RTA should be considered during surgical and non-surgical evaluations.


Subject(s)
Renal Artery , Testis , Adult , Aorta, Abdominal , Cadaver , Cross-Sectional Studies , Female , Humans , Male , Renal Veins
3.
Clin Anat ; 31(5): 734-741, 2018 Jul.
Article in English | MEDLINE | ID: mdl-28960445

ABSTRACT

Cutaneous nerves have branches called vascular branches (VBs) that reach arteries. VBs are thought to be involved in arterial constriction, and this is the rationale for periarterial sympathectomy as a treatment option for Raynaud's disease. However, the branching patterns and distribution areas of the VBs remain largely unclear. The aim of the present study was to investigate the anatomical structures of the VBs of the cutaneous nerves. Forty hands and forearms were examined to assess the branching patterns and distribution areas of the VBs of the superficial branch of the radial nerve (SBRN), the lateral antebrachial cutaneous nerve (LACN), the medial antebrachial cutaneous nerve (MACN), and the palmar cutaneous branch of the ulnar nerve (PCUN). VBs reaching the radial and ulnar arteries were observed in all specimens. The branching patterns were classified into six types. The mean distance between the radial styloid process and the point where the VBs reached the radial artery was 34.3 ± 4.8 mm in the SBRN and 38.5 ± 15.8 mm in the LACN. The mean distance between the ulnar styloid process and the point where the VBs reached the ulnar artery was 60.3 ± 25.9 mm in the MACN and 43.8 ± 26.0 mm in the PCUN. This study showed that the VBs of the cutaneous nerves have diverse branching patterns. The VBs of the SBRN had a more limited distribution areas than those of the other nerves. Clin. Anat. 31:734-741, 2018. © 2017 Wiley Periodicals, Inc.


Subject(s)
Forearm/blood supply , Hand/blood supply , Radial Artery/innervation , Ulnar Artery/innervation , Aged , Aged, 80 and over , Female , Forearm/innervation , Hand/innervation , Humans , Male , Raynaud Disease/surgery
4.
Chem Commun (Camb) ; 53(82): 11298-11301, 2017 Oct 12.
Article in English | MEDLINE | ID: mdl-28920592

ABSTRACT

A simple and fast one-step fabrication method of silver nanoparticles (AgNPs) on a polydimethylsiloxane (PDMS) film and their improvement as highly sensitive surface enhanced Raman scattering (SERS) substrates via atomically thin Au coatings is demonstrated. The thin Au layer provides oxidation resistivity while maintaining the broad spectral range SERS sensitivity of Ag nanoparticles.

5.
Transplant Proc ; 48(4): 1288-91, 2016 May.
Article in English | MEDLINE | ID: mdl-27320606

ABSTRACT

Cellular survival and death are at least partially regulated by the phosphorylation of proteins. A chaperon protein, 14-3-3ζ, regulates the activity of many proteins by covering the phosphorylation site within a 14-3-3 binding motif. Therefore, regulation of 14-3-3ζ activity may affect the fate of cells subjected to cold preservation and/or hypothermic oxygenated conditions. The present study assessed whether 14-3-3ζ protects cells from hypothermic oxygenation-induced injury and clarified its role in mitochondrial functions. Human renal tubular cell line HK-2 or 14-3-3ζ-overexpressed HK-2 (ζHK-2) cells were subjected to 72 hours of normoxic cold preservation in UW solution with or without antioxidants and hydroperoxides. Cellular death, adenosine triphosphate (ATP) content, and MTT catabolism were evaluated. Deferoxamine treatment reduced cellular death and augmented ATP content in both cell types. These indices were higher in ζHK-2, regardless of deferoxamine treatment. Exposure to hydroperoxides did not affect cellular death in either cell type, whereas hydroperoxide supplementation significantly reduced ATP content, except for low-dose hydrogen peroxide in HK-2 cells. MTT assay at normal state showed higher values in ζHK-2 cells, whereas it was impaired by hydroperoxides in both cell types. These results suggest that accumulation of hydroperoxides as a byproduct of the augmented oxidative phosphorylation by 14-3-3ζ overexpression causes mitochondrial dysfunction. In conclusion, despite possessing many potentially protective functions, 14-3-3ζ exacerbates cellular injury under hypothermic oxygenated conditions. 14-3-3ζ accelerates mitochondrial functions together with iron-dependent oxidative damage. Although further investigations are necessary, upregulation of 14-3-3ζ could be a method to maintain mitochondrial function under hypothermic oxygenated conditions, as shown in hypothermic machine preservation of renal grafts, when appropriate antioxidant treatment is administered.


Subject(s)
14-3-3 Proteins/physiology , Kidney Tubules/physiology , 14-3-3 Proteins/metabolism , Adenosine/pharmacology , Allopurinol/pharmacology , Antioxidants/pharmacology , Cardioplegic Solutions/pharmacology , Cell Death/drug effects , Cell Line , Cell Survival/drug effects , Cryopreservation/methods , Deferoxamine/pharmacology , Glutathione/pharmacology , Humans , Insulin/pharmacology , Kidney Tubules/cytology , Kidney Tubules/metabolism , Mitochondria/metabolism , Mitochondria/physiology , Organ Preservation/methods , Organ Preservation Solutions/pharmacology , Oxidative Phosphorylation , Oxidative Stress/physiology , Raffinose/pharmacology , Siderophores/pharmacology
6.
J Phys Condens Matter ; 26(3): 035402, 2014 Jan 22.
Article in English | MEDLINE | ID: mdl-24351274

ABSTRACT

We present a genetic algorithm (GA) for structural search that combines the speed of structure exploration by classical potentials with the accuracy of density functional theory (DFT) calculations in an adaptive and iterative way. This strategy increases the efficiency of the DFT-based GA by several orders of magnitude. This gain allows a considerable increase in the size and complexity of systems that can be studied by first principles. The performance of the method is illustrated by successful structure identifications of complex binary and ternary intermetallic compounds with 36 and 54 atoms per cell, respectively. The discovery of a multi-TPa Mg-silicate phase with unit cell containing up to 56 atoms is also reported. Such a phase is likely to be an essential component of terrestrial exoplanetary mantles.

7.
J Phys Condens Matter ; 19(31): 315219, 2007 Aug 08.
Article in English | MEDLINE | ID: mdl-21694119

ABSTRACT

The transition metal (TM) chalcogenides of the form TMX(2) (X = S or Se) have been studied for decades due to their interesting electronic and magnetic properties such as metamagnetism and metal-insulator transitions. In particular, the Co(1-x)Fe(x)S(2) alloys were the subject of investigation in the 1970s due to general interest in itinerant ferromagnetism. In recent years (2000-present) it has been shown, both by electronic structure calculations and detailed experimental investigations, that Co(1-x)Fe(x)S(2) is a model system for the investigation of highly spin polarized ferromagnetism. The radically different electronic properties of the two endpoint compounds (CoS(2) is a narrow bandwidth ferromagnetic metal, while FeS(2) is a diamagnetic semiconductor), in a system forming a substitutional solid solution allows for composition control of the Fermi level relative to the spin split bands, and therefore composition-controlled conduction electron spin polarization. In essence, the recent work has shown that the concept of 'band engineering' can be applied to half-metallic ferromagnets and that high spin polarization can be deliberately engineered. Experiments reveal tunability in both sign and magnitude of the spin polarization at the Fermi level, with maximum values obtained to date of 85% at low temperatures. In this paper we review the properties of Co(1-x)Fe(x)S(2) alloys, with an emphasis on properties of relevance to half-metallicity. Crystal structure, electronic structure, synthesis, magnetic properties, transport properties, direct probes of the spin polarization, and measurements of the total density of states at the Fermi level are all discussed. We conclude with a discussion of the factors that influence, or even limit, the spin polarization, along with a discussion of opportunities and problems for future investigation, particularly with regard to fundamental studies of spintronic devices.

8.
Phys Rev Lett ; 94(5): 056602, 2005 Feb 11.
Article in English | MEDLINE | ID: mdl-15783672

ABSTRACT

In the emerging field of spin-electronics ideal ferromagnetic electron sources would not only possess a high degree of spin polarization, but would also offer control over the magnitude of this polarization. We demonstrate here that a simple scheme can be utilized to control both the magnitude and the sign of the spin polarization of ferromagnetic CoS2, which we probe with a variety of techniques. The position of the Fermi level is fine-tuned by solid solution alloying with the isostructural diamagnetic semiconductor FeS2, leading to tunable spin polarization of up to 85%.

9.
J Dent Res ; 81(7): 482-6, 2002 Jul.
Article in English | MEDLINE | ID: mdl-12161461

ABSTRACT

The hydrolytic stability of a group of experimental composite materials was evaluated. Seven distinct composites were formed by the mixing of a resin monomer mixture with silica filler that had been pre-treated with one of 7 different ethanol solutions. In one case, the filler was treated with an ethanol solution that contained only 3-methacryloyloxypropyltrimethoxysilane. In 5 cases, it was treated with solution containing a mixture of 3-methacryloyloxypropyltrimethoxysilane and one of the following hydrophobic fluoroalkyltrimethoxysilanes: trifluoropropyl-, nonafluorohexyl-, tridecafluorooctyl-, heptadecafluorodecyl-, and henicosafluorododecyl-trimethoxysilane. The tensile strength, after being immersed in water for 1800 days, of 2 of the experimental composites, whose pre-treatment regimen had included a fluoroalkyltrimethoxysilane, was significantly higher than that of the composite whose pre-treatment regimen had not included a fluoroalkyltrimethoxysilane. Moreover, there was no significant difference between the tensile strength of fresh samples of these 2 composites and the tensile strength of identically produced samples that had remained under water for 1800 days or that had been subjected to 30,000 cycles of thermal stress.


Subject(s)
Composite Resins/chemistry , Dental Materials/chemistry , Silanes/chemistry , Absorption , Alkanes/chemistry , Analysis of Variance , Ethanol/chemistry , Humans , Hydrolysis , Hydrophobic and Hydrophilic Interactions , Immersion , Materials Testing , Methacrylates/chemistry , Silicon Dioxide/chemistry , Silicone Oils/chemistry , Solvents/chemistry , Statistics as Topic , Surface Properties , Tensile Strength , Thermodynamics , Time Factors , Water/chemistry , Wettability
10.
Protein Sci ; 10(11): 2393-400, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11604544

ABSTRACT

The binding of a nitroxide spin-labeled analog of N-acetyllactosamine to galectin-3, a mammalian lectin of 26 kD size, is studied to map the binding sites of this small oligosaccharide on the protein surface. Perturbation of intensities of cross-peaks in the (15)N heteronuclear single quantum coherence (HSQC) spectrum of full-length galectin-3 owing to the bound spin label is used qualitatively to identify protein residues proximate to the binding site for N-acetyllactosamine. A protocol for converting intensity measurements to a more quantitative determination of distances between discrete protein amide protons and the bound spin label is then described. This protocol is discussed as part of a drug design strategy in which subsequent perturbation of chemical shifts of distance mapped amide cross-peaks can be used effectively to screen a library of compounds for other ligands that bind to the target protein at distances suitable for chemical linkage to the primary ligand. This approach is novel in that it bypasses the need for structure determination and resonance assignment of the target protein.


Subject(s)
Oligosaccharides/chemistry , Proteins/chemistry , Amino Sugars/chemistry , Antigens, Differentiation/chemistry , Binding Sites , Cyclic N-Oxides , Drug Design , Galectin 3 , Ligands , Magnetic Resonance Spectroscopy/methods , Protein Interaction Mapping , Spin Labels
12.
Chem Pharm Bull (Tokyo) ; 49(2): 203-5, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11217110

ABSTRACT

Rapid and precise compositional analysis of copoly (DL-lactic/glycolic acid) (PLGA) was performed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) combined with one-step hydrolysis and methylation in the presence of tetramethylammonium hydroxide (TMAH). Pyrolysis of PLGA with TMAH gave two characteristic products, derivatives of DL-lactic acid and glycolic acid, which directly reflect the average molar composition of PLGA. The analytical results for PLGA samples with various compositional ratios were in good agreement with those obtained by 1H-NMR spectrometry, and the precision was satisfactory.


Subject(s)
Gas Chromatography-Mass Spectrometry/methods , Lactic Acid/chemistry , Polyglycolic Acid/chemistry , Polymers/chemistry , Quaternary Ammonium Compounds/chemistry , Hydrolysis , Magnetic Resonance Spectroscopy , Methylation , Polylactic Acid-Polyglycolic Acid Copolymer , Sensitivity and Specificity
13.
Chem Pharm Bull (Tokyo) ; 48(12): 1894-7, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11145139

ABSTRACT

Thermal desorption (TD) techniques followed by capillary GC/MS were applied for the analysis of residual solvents in bulk pharmaceuticals. Solvents desorbed from samples by heating were cryofocused at the head of a capillary column prior to GC/MS analysis. This method requires a very small amount of sample and no sample pretreatment. Desorption temperature was set at the point about 20 degrees C higher than the melting point of each sample individually. The relative standard deviations of this method tested by performing six consecutive analyses of 8 different samples were 1.1 to 3.1%, and analytical results of residual solvents were in agreement with those obtained by direct injection of N,N-dimethylformamide solution of the samples into the GC. This novel TD/GC/MS method was demonstrated to be very useful for the identification and quantification of residual solvents in bulk pharmaceuticals.


Subject(s)
Gas Chromatography-Mass Spectrometry , Pharmaceutical Preparations/analysis , Solvents/analysis , Chemistry, Pharmaceutical/methods , Drug Contamination , Quality Control , Reference Standards , Temperature
14.
Inorg Chem ; 39(22): 5074-82, 2000 Oct 30.
Article in English | MEDLINE | ID: mdl-11233204

ABSTRACT

Combining three units of one of H-(alanyl)n-beta-(HO)alanyl peptides (n = 1-3) with nitrilotriacetic acid affords tripodal peptide hydroxamate ligands (1L, 1D, 2LL, 2DL, and 3LLL, where each L or D denotes the L- or D-alanyl residue). These ligands form six-coordinate octahedral complexes (Fe-1L, Fe-1D, Fe-2LL, Fe-2DL, and Fe-3LLL) with iron(III) in aqueous near neutral pH solution, and the stability and the chirality of the complexes formed depend on the alanyl residues incorporated. Thus Fe-2LL is the most stable against attack of H+ and OH- ions and the least labile in the iron(III) removal by EDTA. The CD spectra show a predominance of the A configuration for Fe-1D, Fe-2LL, Fe-2DL, and Fe-3LLL, but the opposite delta configuration for Fe-1L. These ligands and their gallium(III) complexes are studied by 1H NMR spectroscopy in DMSO-d6 solution. CD and NMR spectral analysis, aided by molecular model examinations, indicates that critical factors in controlling the configuration and the stability of the complexes are (1) the hydroxamate-carrying alanyl residue, (2) the expanse of an interior space in the ligand, and (3) an interstrand amide NH hydrogen bond; the latter bonding is possible with ligands 2LL and 2DL. A microbial growth promotion activity test shows that ligands 1L, 2LL, and 3LLL all act as iron-transporting agents.


Subject(s)
Alanine/chemistry , Ferric Compounds/chemistry , Iron Chelating Agents/chemical synthesis , Nitrilotriacetic Acid/chemistry , Oligopeptides/chemistry , Siderophores/chemistry , Edetic Acid/chemistry , Escherichia coli/drug effects , Escherichia coli/growth & development , Ferric Compounds/pharmacology , Hydrogen-Ion Concentration , Hydroxamic Acids/chemistry , Ion Exchange , Iron Chelating Agents/chemistry , Iron Chelating Agents/pharmacology , Kinetics , Ligands , Magnetic Resonance Spectroscopy , Models, Chemical , Nitrilotriacetic Acid/pharmacology , Oligopeptides/pharmacology , Spectrophotometry, Infrared , Spectrophotometry, Ultraviolet
15.
J Biomater Sci Polym Ed ; 10(6): 621-39, 1999.
Article in English | MEDLINE | ID: mdl-10385224

ABSTRACT

This paper describes the synthesis and biodegradation of copolymers of cyclic depsipeptide with epsilon-caprolactone (CL) or lactide (LA). Optically active cyclic depsipeptides, 3,6-dimethyl-2,5-morpholinediones (DMOs), were prepared by the reaction of an amino acid (D-, L-, or DL-alanine) with a hydroxy acid derivative (DL-2-bromopropionyl bromide). These isomers are abbreviated as D-DMO, L-DMO and DL-DMO respectively, according to the names of alanine isomers. Then, we have prepared the copolymers of DMO isomers with CL using tin(II) octylate as a catalyst. The NMR spectra and thermal properties of DMO/CL copolymers revealed that these copolymers exist randomly. The enzymatic degradation of the copolymers has been examined using Rhizopus delemar lipase, cholesterol esterase (from Pseudomonas sp.), and Proteinase K (from Tritirachium album). Cholesterol esterase and Proteinase K show high degradability, while the lipase shows little degradation. Among the enzymes used, only Proteinase K could recognize the isomerism of DMO, resulting in the following order of degradability: copoly(L-DMO/CL) > copoly(DL-DMO/CL) > copoly(D-DMO/CL), i.e. this enzyme has the highest substrate specificity for naturally occurring L-alanine. Further, we have prepared the random copolymers of L-DMO with lactide (L-LA or DL-LA), and evaluated the enzymatic degradation of the copolymers by Proteinase K. The introduction of a small amount (up to c. 10 mol%) of L-DMO unit into LA homopolymers brought about greater degradability compared with LA homopolymers. In particular, L-DMO/L-LA copolymers with high degradability have been obtained without significant decrease in the mechanical and thermal properties of L-LA homopolymer.


Subject(s)
Isomerism , Polymers/chemical synthesis , Endopeptidase K/metabolism , Microscopy, Electron, Scanning , Peptides, Cyclic/chemistry , Polyesters/chemistry , Temperature , Time Factors
16.
FEBS Lett ; 418(1-2): 76-82, 1997 Nov 24.
Article in English | MEDLINE | ID: mdl-9414099

ABSTRACT

Investigation of the width of the minor groove using 500 MHz NMR spectroscopy in three closely related 11-mer B-DNA duplexes shows that the minor groove is narrow in a GC rich oligonucleotide, and that a narrow minor groove is not something endemic to DNAs with persistent repetitions of adenine nucleotides (A-tract DNA). The width of the groove is dictated by local sequence contexts and independent of neighboring A-tract DNA.


Subject(s)
DNA/chemistry , Nucleic Acid Conformation , Oligodeoxyribonucleotides/chemistry , Base Composition , Base Sequence , Cytosine , Guanine , Nuclear Magnetic Resonance, Biomolecular
17.
Dent Mater J ; 16(1): 21-30, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9549998

ABSTRACT

To improve the water sorption of poly(methyl methacrylate), new hydrophobic monomers, such as norbonyl and phenyl methacrylate, were studied to determine the resin with lower water sorption with no decrease in mechanical property. Water sorption of the copolymers of the hydrophobic monomers and MMA decreased with the increase in the concentration of the monomers. Compressive and bending strength of the copolymers were higher than that of PMMA, and the elastic modulus in bending was the same as that of PMMA. In addition, the transverse-deflection values satisfied ADA specifications. Dynamic mechanical thermal analysis of the copolymers showed a similar tendency to that of PMMA in spite of the introduction of bulky groups, such as norbonyl and phenyl, in the polymer molecule. The polymerization shrinkage in volume was in the following order: norbonyl < phenyl < methyl methacrylate.


Subject(s)
Denture Bases , Polymethyl Methacrylate/chemistry , Compressive Strength , Differential Thermal Analysis , Elasticity , Hydrolysis , Materials Testing , Methacrylates/chemistry , Polymers/chemistry , Tensile Strength , Wettability
18.
J Cardiol ; 28(4): 213-20, 1996 Oct.
Article in English | MEDLINE | ID: mdl-8934337

ABSTRACT

Histological findings in the acute phase of myocarditis were evaluated as a prediction of hemodynamic state in the chronic phase in 20 patients with clinical and pathological diagnoses of myocarditis who were followed up with echocardiography for at least 1 year. Endomyocardial biopsy samples were obtained from the left ventricle within 1 year of the onset of symptoms. Azan-Mallory staining was performed on the myocytes, which were categorized as either well stained or poorly stained. The point counting method was used to determine the fraction of each type. The improvement in ejection fraction within 1 year correlated significantly with the fraction of poorly stained myocytes (r = 0.46, p < 0.05). The ejection fraction at biopsy was negatively correlated with the volume fraction of well stained myocytes (r = -0.64, p < 0.01). The staining condition of myocytes may be useful in predicting the hemodynamic recovery of patients with myocarditis.


Subject(s)
Myocarditis/pathology , Myocarditis/physiopathology , Myocardium/pathology , Ventricular Function , Acute Disease , Adult , Aged , Biopsy , Endocardium/pathology , Female , Follow-Up Studies , Hemodynamics , Humans , Male , Middle Aged , Prognosis , Staining and Labeling , Stroke Volume , Tissue Survival
19.
Dent Mater J ; 14(2): 135-42, 1995 Dec.
Article in English | MEDLINE | ID: mdl-8940552

ABSTRACT

Mixed salines, 3-methacryloxypropylsilytriisocyanate and 3-mercaptopropyltrimethoxysilane, were used as primers for adhesion of poly(methyl methacrylate) to porcelain teeth, precious alloys and nonprecious alloys. After thermocycle testing, the mean bond strength of the resin to porcelain, silver alloys and stainless steel were excellent. The fracture patterns of porcelain teeth after thermocycling followed by adherent testing were similar to those of specimens subjected to 48-hour water immersion at 37 degrees C. Two specimens failed cohesively in the porcelain and the other specimens failed in the resin. The mixed primer had no effect on cobalt-chromium alloy specimens.


Subject(s)
Dental Alloys , Dental Bonding , Dental Cements/chemistry , Dental Porcelain , Silanes/chemistry , Boron Compounds , Chromium Alloys , Gold Alloys , Materials Testing , Methacrylates/chemistry , Methylmethacrylates , Silver , Stainless Steel , Tensile Strength
20.
Int J Biol Macromol ; 17(3-4): 227-35, 1995 Jun.
Article in English | MEDLINE | ID: mdl-7577822

ABSTRACT

Molecular dynamics (MD) simulations of methyl N,N'-diacetyl-beta-D-chitobioside (GlcNAc beta-(1-->4)GlcNAc beta-OMe) have been performed both in vacuo and in aqueous solution with the explicit inclusion of the solvent water molecules. The beta-(1-->4) glycosidic linkage fluctuates considerably, over a range of +/- 10 degrees, in each of the MD simulations in vacuo and in aqueous solution. The intra- and inter-residue hydrogen bonds in vacuo are replaced by intermolecular hydrogen bonds with the solvent water molecules in aqueous solution. Multiple conformations (gg and gt) exist for the exocyclic hydroxymethyl groups. The results of the MD simulations are compared with those of 1H-1H nuclear Overhauser effect measurements.


Subject(s)
Disaccharides/chemistry , Carbohydrate Conformation , Carbohydrate Sequence , Computer Simulation , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Sequence Data , Software , Solutions , Solvents , Time Factors
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