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Localized Areas (localized + area)
Selected AbstractsWide area illumination Raman scheme for simple and nondestructive discrimination of seawater cultured pearlsJOURNAL OF RAMAN SPECTROSCOPY, Issue 12 2009Seok Chan Park Abstract Raman spectroscopy, along with discriminant partial least squares (PLS), was successfully used to discriminate among three different groups of cultured pearls (fresh water, Akoya and South seawater). The discrimination between Akoya and South seawater pearls using XRF (X-ray fluorescence), one of the most frequently adopted analytical methods in pearl analysis, has been especially difficult owing to their similar mineral compositions. The selective Raman features helped in effectively discriminating between these two pearl groups. The difference in the intensities of the CaCO3 bands of Akoya and South seawater pearls provided a valuable clue. Along with the selective Raman feature, a reproducible Raman spectral collection achieved using a wide area illumination (WAI) scheme played an important role in the determination of the pearl groups, although the pearls were hard-surfaced, round, solid samples of different sizes and surface shapes. Unwanted spectral variation originating from sensitivity to sample placement relative to the focal plane and from unsuccessful sample representation due to the probing of a localized area, factors that could possibly deteriorate Raman reproducibility, were substantially lessened using the WAI scheme. ATR (attenuated total reflection) IR spectroscopy requiring direct contact with the pearl could be inadequate for discrimination or classification where large numbers of repeating and reproducible measurements are required. Copyright © 2009 John Wiley & Sons, Ltd. [source] Ultra-Small-Angle X-Ray Scattering Study of PET/PC Nanolayers and Comparison to AFM ResultsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 13 2008Fernando Ania Abstract The forced assembly of two immiscible polymers, produced by layer-multiplying co-extrusion, is analyzed by means of USAXS. Comparison of scattering and AFM results sheds light on many details of the nanolayered structure in PET/PC films. The role played by the volume concentration and cold crystallization of PET on the experimental scattering is discussed. The appearance of at least two scattering maxima in all cases, corresponding to higher orders of the same repeating distance, accounts for the high regularity of the developed nanostructure. It is finally shown that long spacing values, derived from a localized area in AFM, are in a good agreement with the USAXS values averaged over much larger areas. [source] Effect of Ventricular Fibrillation Duration on the Defibrillation Threshold in HumansPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2002RAINER GRADAUS GRADAUS, R., et al.: Effect of Ventricular Fibrillation Duration on the Defibrillation Threshold in Humans. Early during ventricular fibrillation, the defibrillation threshold may be low, as ventricular fibrillation most probably arises from a localized area with only a few wavefronts and the effects of global ischemia, ventricular dilatation, and sympathetic discharge have not yet fully developed. The purpose of this study was to explore the effect of the timing of shock delivery in humans. During implantation of an ICD in 26 patients (24 men, 60 ± 11 years, 19 coronary artery disease, NYHA 2.2 ± 0.4, left ventricular ejection fraction 0.42 ± 0.16), the defibrillation threshold was determined after approximately 10 and 2 seconds of ventricular fibrillation. Ventricular fibrillation was induced by T wave shocks. Mean defibrillation threshold was 9.9 ± 3.6 J after 10.3 ± 1.0 seconds. Within 2 seconds, 20 of 26 patients could be successfully defibrillated with , 8 J. In these patients, the mean defibrillation threshold was 4.0 ± 2.1 J after 1.4 ± 0.3 seconds compared to 9.5 ± 3.1 J after 10.2 ± 1.1 seconds (P < 0.001). There were no clinical differences between patients who could be successfully defibrillated within 2 seconds and those patients without successful defibrillation within 2 seconds. In the majority of patients, the defibrillation threshold was significantly lower within the first few cycles of ventricular fibrillation than after 10 seconds of ventricular fibrillation. These results should lead to exploration of earlier shock delivery in implantable devices. This could possibly reduce the incidence of syncope in patients with rapid ventricular tachyarrhythmias and ICDs. [source] Bilateral Coats' disease: long-term follow upACTA OPHTHALMOLOGICA, Issue 1 2002Anastassia Alexandridou ABSTRACT. Purpose: To report on the long-term follow-up of a female patient with bilateral Coats' disease, who showed marked asymmetry between the two eyes. Methods: A five year old girl presented in 1978 with leukocoria in a blind right eye. A total exudative retinal detachment and extensive retinal telangiectasiae were noted. In the other eye, there was a localized area of retinal exudation and vascular abnormality in the supero-temporal periphery. Ultrasonography showed no evidence of intraocular tumour in the right eye and a clinical diagnosis of bilateral Coats' disease was made. Results: In 1995, the area or retinal exudation in the left eye increased and laser photocoagulation was applied successfully. To date, no disease recurrences have occurred. Conclusion: Although Coats' disease is usually unilateral, bilateral, asymmetrical involvement may occur on rare occasions. Long-term follow-up of the least affected eye is necessary so that late complications can be identified early and treated adequately to prevent visual loss. [source] The crystal structure of a plant 2C -methyl- D -erythritol 4-phosphate cytidylyltransferase exhibits a distinct quaternary structure compared to bacterial homologues and a possible role in feedback regulation for cytidine monophosphateFEBS JOURNAL, Issue 5 2006Mads Gabrielsen The homodimeric 2C -methyl- d -erythritol 4-phosphate cytidylyltransferase contributes to the nonmevalonate pathway of isoprenoid biosynthesis. The crystal structure of the catalytic domain of the recombinant enzyme derived from the plant Arabidopsis thaliana has been solved by molecular replacement and refined to 2.0 Å resolution. The structure contains cytidine monophosphate bound in the active site, a ligand that has been acquired from the bacterial expression system, and this observation suggests a mechanism for feedback regulation of enzyme activity. Comparisons with bacterial enzyme structures, in particular the enzyme from Escherichia coli, indicate that whilst individual subunits overlay well, the arrangement of subunits in each functional dimer is different. That distinct quaternary structures are available, in conjunction with the observation that the protein structure contains localized areas of disorder, suggests that conformational flexibility may contribute to the function of this enzyme. [source] A physiological interpretation of pattern changes in a flatfishJOURNAL OF FISH BIOLOGY, Issue 3 2008D. Burton The pattern-related capacity for the dispersion of previously aggregated melanosomes in low concentrations (3 × 10,6 to 10,8 M) of noradrenaline in vitro was observed in melanophores from winter flounder Pseudopleuronectes americanus. With 10,8 M noradrenaline, dispersion was completed more rapidly than in controls using the incubation vehicle alone. Melanophores from white-spot, dark-band and general background components of the integumentary pattern displayed different ,transition ranges' between melanosome aggregation and dispersion in higher and lower concentrations of noradrenaline. Within each ,transition range' individual noradrenaline concentration decrements could result in highly variable degrees of melanosome dispersion. The relative breadth of the noradrenaline ,transition range' concentrations could be represented as dark bands > general background > white spots. The threshold noradrenaline concentration for dispersion was highest for the dark bands. It is concluded that these differences represent variations in the transition from melanophore ,-adrenoceptor-mediated pigment aggregation to ,-adrenoceptor-mediated dispersion between localized areas of the skin. Such variations in ,transition range' will have an important role in the expression of flatfish patterns and in their changes in colour and texture. [source] The Effect of Dowel Space on the Bond Strengths of Fiber PostsJOURNAL OF PROSTHODONTICS, Issue 3 2007Jorge Perdigão DMD Purpose: The purpose of this study was to evaluate the effect of the degree of mismatch between post space and post diameters on the bond strength of a fiber-reinforced resin post. Materials and Methods: Thirty-two extracted human maxillary central incisors and canines were endodontically treated and assigned to four groups: Group 1 - Canal prepared with a D.T. Light Post #1 drill (control); Group 2 - Canal prepared with a D.T. Light Post #2 drill; Group 3 - Canal prepared with a D.T. Light Post #3 drill; Group 4 - Canal prepared with a Gates Glidden #6 drill. A D.T. Light Post size 1 was then luted into the canal using One-Step Adhesive and Post Cement Hi-X. A push-out test was performed on three sections of each root to measure push-out bond strengths. Data were analyzed with ANOVA and Bonferroni's test at p < 0.05. Two extra teeth for each group were restored in the same fashion and processed for SEM observation. Results: (in MPa): Group 1: 15.7 ± 6.9; Group 2: 14.7 ± 6.5; Group 3: 14.0 ± 5.0; Group 4: 14.0 ± 5.1. The variable "post space" resulted in no statistically significant difference in mean bond strengths (p > 0.05). For the variable "root region," the coronal third (17.5 ± 6.0) resulted in statistically greater mean bond strengths than the apical third (12.3 ± 6.0) at p < 0.008. The middle third (14.0 ± 5.3) resulted in no statistically significant different mean bond strengths from the coronal third at p > 0.119 and from the apical third at p > 0.999. Under the SEM, some areas of the canal system still displayed residual gutta-percha, which resulted in debonding of the interface between the resin cement and dentin. Areas with incomplete dentin hybridization were observed in localized areas of all groups. Conclusions: The diameter of the post space did not affect the push-out bond strengths. Bonding at the coronal level of the root canal is more reliable than bonding at the apical level. The presence of residual gutta-percha and the deficient dentin hybridization may result in deficient seal of the resin,dentin interface. [source] Leptomeningeal carcinomatosis from urinary bladder adenocarcinoma: A clinicopathological case studyNEUROPATHOLOGY, Issue 1 2005Kaoru Sugimori We report a 73-year-old male patient with leptomeningeal metastasis from urinary bladder adenocarcinoma. He was presented, with, prominent, hyperactive, delirium, during the course of the disease. Meningeal carcinomatosis was detected 5 days before his death, but the primary site of the malignant tumor could not be determined. Necropsy revealed leptomeningeal infiltration of many adenocarcinoma cells that covered the cerebrum. The leptomeninges of the right middle frontal gyrus, superior temporal gyrus, precentral gyrus and inferior parietal lobe were most severely affected by tumor cell infiltration. Cerebral edema was found to extensively cover the basal part of the temporal lobe. In the cerebrum, tumor cells were clustered in the perivascular spaces and had invaded localized areas of the frontal lobe. Vascular cell adhesion molecule (VCAM)-1 expression was detected in the small vessels of the cerebral upper cortical layers and of temporal subcortical u-fibers. Numerous astrocytes positive for cytokeratin AE1/AE3 were found in the frontal and temporal lobes. Meningeal carcinomatosis from urinary bladder adenocarcinoma is extremely rare and up-regulation of the adhesion molecules in the meningeal adenocarcinoma was confirmed. [source] Liposomes in investigative dermatologyPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 5 2001Daniel B. Yarosh Liposomes are microscopic spheres, usually composed of amphiphilic phospholipids. They may be useful without skin penetration if they simply protect or sequester compounds that would otherwise be unstable in the formulation. Liposomes that remain on the skin surface are useful as light-absorbers, agents to deliver color or sunscreens, or as depots for timed-release. Liposomes that penetrate the stratum corneum have the potential to interact with living tissue. Topically applied liposomes can either mix with the stratum corneum lipid matrix or penetrate the stratum corneum by exploiting the lipid-water interface of the intercellular matrix. There are at least four major routes of entry into the skin: pores, hair follicles, columnular spaces and the lipid:water matrix between squames. A major force driving liposome penetration is the water gradient, and flexible liposomes are best able to exploit these delivery opportunities. Some liposomes release their contents extracellularly. Topical application of photosensitizers may be enhanced by encapsulation in liposomes. Higher and longer-lasting drug concentrations may be produced in localized areas of skin, particularly at disease sites where the stratum corneum and the skin barrier function are disrupted. The liposome membrane should be designed to capture lipophilic drugs in the membrane or hydrophilic drugs in the interior. Other types of liposomes can be engineered to be taken up by cells. Once inside cells, the lysosomal sac and clatherin-coated pit are the dead-end destinations for liposomes unless an escape path has been engineered into the liposome. A novel method has been developed to allow delivery into cells of the skin, by escape from the lysosomal sac. These liposomes have been used to topical deliver active DNA repair enzymes from liposomes into epidermal cells and to enhance DNA repair of UV-irradiated skin. From these studies a tremendous amount has been learned about the relationship of DNA damage and skin cancer. Both mutations and immunosuppression appear to be essential to skin cancer and both are induced by DNA damage. DNA damage produces immediate effects by inducing the expression of cytokines, which means that DNA damage can induce signaling in neighboring, undamaged cells. The repair of only a fraction of the DNA damage has a disproportionate effect on the biological responses, clearly demonstrating that not all DNA damage is equivalent. This technology demonstrates that biologically active proteins can be delivered into the cells of skin, and opens up a new field of correcting or enhancing skin cell metabolism to improve human health. [source] Characterization of a prolyl endoprotease from Eurygaster integriceps puton (Sunn pest) infested wheatARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2010Charles Darkoh Abstract Sunn pest, Eurygaster integriceps, Puton, infested and uninfested wheat seeds were obtained from the International Center for Agriculture Research in the Dry Areas (ICARDA), Aleppo, Syria, with the primary objective to identify the type of enzyme deposited by the Sunn pest on the wheat responsible for the gluten degradation. Enzyme levels were extremely low due to the enzyme being secreted by the insect in localized areas on the seed. Only extract from the infested wheat contained glutenase activity. Anion exchange, Cu2+ sepharose, and gel filtration chromatography were used to partially purify and enrich protein samples from both infested wheat and uninfested wheat. An SDS-gluten assay was used to show gluten specificity while a commercially available chromogenic proline peptide, benzyloxycarbonyl-Gly-Pro-p-nitroanalide (ZGPpNA), was utilized to identify fractions containing the active proline specific enzyme activity and to determine Michaelis-Menten kinetics. Despite low levels of enzyme on the infested wheat, the enzyme was partially purified and enriched exhibiting a specific activity of 4.5,U/mg of total protein for gluten in a SDS gluten assay (1,U of enzyme activity was defined as the decrease in gel height in millimeters in 1,h) and exhibited a high-affinity Km of 65,µM for ZGPpNA, cleaving at the carboxy terminus of the proline residue. The enzyme exhibited optimal activity between pH 8 and 10.0 at temperatures between 20° and 35°C. The enzyme was identified to be a prolyl endoprotease. © 2010 Wiley Periodicals, Inc. [source] | |||||||||||||