977 resultados para Cement thickness


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PURPOSE: To investigate relationship between placental thickness during the second and third trimesters and placental and birth weights. METHODS: From January 2011 to June 2012, a total of 250 singleton pregnant women presented at our antenatal clinic were enrolled in this prospective study. All recruited women were assessed at the 1st trimester screening for baseline demographic and obstetric data. The placental thickness was measured trans-abdominally by placing the ultrasound transducer perpendicularly to the plane of the placenta, in the area of the cord insertion at second and third trimester. Pearson's correlation analysis was used to establish the degree of relationship between placental thickness and birth and placental weights. RESULTS: Of 250 recruited participants, 205 women were able to complete the study. The mean age of cases was 26.4±5.1. Values of mean birth and placental weights were 305.56±657.0 and 551.7±104.8 grams respectively. Ultrasonographic measures of placental thickness in second and third trimester and changes between them were 21.68±4.52, 36.26±6.46 and 14.67±5.67 mm respectively. There was a significant positive correlation between placental thickness and birth weight in the second and third trimesters (r=0.15, p=0.03; r=0.14, p=0.04 correspondingly). CONCLUSION: According to our study, birth weight has a positive relation with both second and third trimester placental thickness; however, placental thickness change could not predict low birth weight.

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Herbicides used in Clearfield(r) rice system may persist in the environment, damaging non-tolerant crops sown in succession and/or rotation. These damages vary according to soil characteristics, climate and soil management. The thickness of the soil profile may affect carryover effect; deeper soils may allow these molecules to leach, reaching areas below the roots absorption zone. The aim of this study was to evaluate the effect of the thickness of soil profile in the carryover of imazethapyr + imazapic on ryegrass and non-tolerant rice, sown in succession and rotation to rice, respectively. Lysimeters of different thicknesses (15, 20, 30, 40, 50 and 65 cm) were constructed, where 1 L ha-1 of the imazethapyr + imazapic formulated mixture was applied in tolerant rice. Firstly, imidazolinone-tolerant rice was planted, followed by ryegrass and non-tolerant rice in succession and rotation, respectively. Herbicide injury, height reduction and dry weight of non-tolerant species were assessed. There was no visual symptoms of herbicide injury on ryegrass sown 128 days after the herbicide application; however it causes dry weight mass reduction of plants. The herbicides persist in the soil and cause injury in non-tolerant rice, sown 280 days after application, and the deeper the soil profile, the lower the herbicides injury on irrigated rice.

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The aim of this study was to analyze the thickness of the intima-media complex (IMC) using a noninvasive method. The carotid and femoral common arteries were evaluated by noninvasive B-mode ultrasound in 63 normotensive and in 52 hypertensive subjects and the thickness of the IMC was tested for correlation with blood pressure, cardiac structures and several clinical and biological parameters. The IMC was thicker in hypertensive than in normotensive subjects (0.67 ± 0.13 and 0.62 ± 0.16 vs 0.54 ± 0.09 and 0.52 ± 0.11 mm, respectively, P<0.0001). In normotensive patients, the simple linear regression showed significant correlations between IMC and age, body mass index and 24-h systolic blood pressure for both the carotid and femoral arteries. In hypertensives the carotid IMC was correlated with age and 24-h systolic blood pressure while femoral IMC was correlated only with 24-h diastolic blood pressure. Forward stepwise regression showed that age, body mass index and 24-h systolic blood pressure influenced the carotid IMC relationship (r2 = 0.39) in normotensives. On the other hand, the femoral IMC relationship was influenced by 24-h systolic blood pressure and age (r2 = 0.40). In hypertensives, age and 24-h systolic blood pressure were the most important determinants of carotid IMC (r2 = 0.37), while femoral IMC was influenced only by 24-h diastolic blood pressure (r2 = 0.10). There was an association between carotid IMC and echocardiographic findings in normotensives, while in hypertensives only the left posterior wall and interventricular septum were associated with femoral IMC. We conclude that age and blood pressure influence the intima-media thickness, while echocardiographic changes are associated with the IMC.

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Kartta kuuluu A. E. Nordenskiöldin kokoelmaan

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Cement industry significantly associated with high greenhouse gas (GHG) emissions. Considering the environmental impact, particularly global warming potential, it is important to reduce these emissions to air. The aim of the study is to investigate the mitigation possibility of GHG emissions in Ethiopian cement industry. Life cycle assessment (LCA) method used to identify and quantify GHG emissions during one ton of ordinary portland cement (OPC) production. Three mitigation scenarios: alternative fuel use, clinker substitution and thermal energy efficiency were applied on a representative gate-to-gate flow model developed with GaBi 6 software. The results of the study indicate that clinker substitution and alternative fuel use play a great role for GHG emissions mitigation with affordable cost. Applying most energy efficient kiln technology, which in turn reduces the amount of thermal energy use, has the least GHG emissions reduction intensity and high implementation cost comparing to the other scenarios. It was found that the cumulative GHG emissions mitigation potential along with other selected mitigation scenarios can be at least 48.9% per ton of cement production.

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The aim of the present study was to measure full epidermal thickness, stratum corneum thickness, rete length, dermal papilla widening and suprapapillary epidermal thickness in psoriasis patients using a light microscope and computer-supported image analysis. The data obtained were analyzed in terms of patient age, type of psoriasis, total body surface area involvement, scalp and nail involvement, duration of psoriasis, and family history of the disease. The study was conducted on 64 patients and 57 controls whose skin biopsies were examined by light microscopy. The acquired microscopic images were transferred to a computer and measurements were made using image analysis. The skin biopsies, taken from different body areas, were examined for different parameters such as epidermal, corneal and suprapapillary epidermal thickness. The most prominent increase in thickness was detected in the palmar region. Corneal thickness was more pronounced in patients with scalp involvement than in patients without scalp involvement (t = -2.651, P = 0.008). The most prominent increase in rete length was observed in the knees (median: 491 µm, t = 10.117, P = 0.000). The difference in rete length between patients with a positive and a negative family history was significant (t = -3.334, P = 0.03), being 27% greater in psoriasis patients without a family history. The differences in dermal papilla distances among patients were very small. We conclude that microscope-supported thickness measurements provide objective results.

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Our objective was to study the effect of dorzolamide on corneal hydration in an 18-week controlled experiment using ultrasonic pachymetry. Twenty-eight male rabbits were divided randomly into four groups. The 7 rabbits in each group received eye drops containing either 2% (w/v) dorzolamide or placebo in their right eye, or in their left eye. The 2% dorzolamide rabbits were treated every 8 h. Fellow eyes are defined as eyes which did not receive either dorzolamide or placebo. The study was blind for both the person who applied the drug and the one who performed the pachymetry. The effect of treatments is reported on the basis of the percentage of pachymetric variation compared to the measurement made before drug application. There was no significant difference (P = 0.061) in pachymetric variation between dorzolamide (-4.42 ± 11.71%) and placebo (2.48 ± 9.63%). However, there was a significant difference (P = 0.0034) in pachymetric variation between the dorzolamide fellow eyes (-7.56 ± 10.50%) and the placebo (-4.42 ± 11.71%). In conclusion, dorzolamide did not increase the corneal thickness in rabbits.

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To study the dendritic morphology of retinal ganglion cells in wild-type mice we intracellularly injected these cells with Lucifer yellow in an in vitro preparation of the retina. Subsequently, quantified values of dendritic thickness, number of branching points and level of stratification of 73 Lucifer yellow-filled ganglion cells were analyzed by statistical methods, resulting in a classification into 9 groups. The variables dendritic thickness, number of branching points per cell and level of stratification were independent of each other. Number of branching points and level of stratification were independent of eccentricity, whereas dendritic thickness was positively dependent (r = 0.37) on it. The frequency distribution of dendritic thickness tended to be multimodal, indicating the presence of at least two cell populations composed of neurons with dendritic diameters either smaller or larger than 1.8 µm ("thin" or "thick" dendrites, respectively). Three cells (4.5%) were bistratified, having thick dendrites, and the others (95.5%) were monostratified. Using k-means cluster analysis, monostratified cells with either thin or thick dendrites were further subdivided according to level of stratification and number of branching points: cells with thin dendrites were divided into 2 groups with outer stratification (0-40%) and 2 groups with inner (50-100%) stratification, whereas cells with thick dendrites were divided into one group with outer and 3 groups with inner stratification. We postulate, that one group of cells with thin dendrites resembles cat ß-cells, whereas one group of cells with thick dendrites includes cells that resemble cat a-cells.

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Subclinical hypothyroidism (SHT) is a disease for which exact therapeutic approaches have not yet been established. Previous studies have suggested an association between SHT and coronary heart disease. Whether this association is related to SHT-induced changes in serum lipid levels or to endothelial dysfunction is unclear. The aim of this study was to determine endothelial function measured by the flow-mediated vasodilatation of the brachial artery and the carotid artery intima-media thickness (IMT) in a group of women with SHT compared with euthyroid subjects. Triglycerides, total cholesterol, HDL-C, LDL-C, apoprotein A (apo A), apo B, and lipoprotein(a) were also determined. Twenty-one patients with SHT (mean age: 42.4 ± 10.8 years and mean thyroid-stimulating hormone (TSH) levels: 8.2 ± 2.7 µIU/mL) and 21 euthyroid controls matched for body mass index, age and atherosclerotic risk factors (mean age: 44.2 ± 8.5 years and mean TSH levels: 1.4 ± 0.6 µIU/mL) participated in the study. Lipid parameters (except HDL-C and apo A, which were lower) and IMT values were higher in the common carotid and carotid bifurcation of SHT patients with positive serum thyroid peroxidase antibodies (TPO-Ab) (0.62 ± 0.2 and 0.62 ± 0.16 mm for the common carotid and carotid bifurcation, respectively) when compared with the negative TPO-Ab group (0.55 ± 0.24 and 0.58 ± 0.13 mm, for common carotid and carotid bifurcation, respectively). The difference was not statistically significant. We conclude that minimal thyroid dysfunction had no adverse effects on endothelial function in the population studied. Further investigation is warranted to assess whether subclinical hypothyroidism, with and without TPO-Ab-positive serology, has any effect on endothelial function.

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Physical training influences the cells and mediators involved in skin wound healing. The objective of this study was to determine the changes induced by different intensities of physical training in mouse skin wound healing. Ninety male C57BL6 mice (8 weeks old, 20-25 g) were randomized into three physical training groups: moderate (70% VO2max), high (80% VO2max), and strenuous intensity (90% VO2max). Animals trained on a motorized treadmill for 8 weeks (Elesion: physical training until the day of excisional lesion, N = 10) or 10 weeks (Eeuthan: physical training for 2 additional weeks after excisional lesion until euthanasia, N = 10), five times/week, for 45 min. Control groups (CG) trained on the treadmill three times/week only for 5 min (N = 10). In the 8th week, mice were anesthetized, submitted to a dorsal full-thickness excisional wound of 1 cm², and sacrificed 14 days after wounding. Wound areas were measured 4, 7, and 14 days after wounding to evaluate contraction (d4, d7 and d14) and re-epithelialization (d14). Fragments of lesion and adjacent skin were processed and submitted to routine histological staining. Immunohistochemistry against alpha-smooth muscle actin (α-SMA) was performed. Moderate-intensity training (M) until lesion (M/Elesion) led to better wound closure 7 days after wounding compared to controls and M/Eeuthan (P < 0.05), and both moderate-intensity groups showed better re-epithelialization rates than controls (M/Elesion = 85.9%, M/Eeuthan = 96.4% and M/CG = 79.9%; P < 0.05). Sections of M/Elesion and M/Eeuthan groups stained with hematoxylin-eosin, Picrosirius red and α-SMA showed the most mature granulation tissues among all trained groups and controls. Thus, moderate-intensity physical training improves skin wound healing.

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Full contour monolithic zirconia restorations have shown an increased popularity in the dental field over the recent years, owing to its mechanical and acceptable optical properties. However, many features of the restoration are yet to be researched and supported by clinical studies to confirm its place among the other indirect restorative materials This series of in vitro studies aimed at evaluating and comparing the optical and mechanical properties, light cure irradiance, and cement polymerization of multiple monolithic zirconia material at variable thicknesses, environments, treatments, and stabilization. Five different monolithic zirconia materials, four of which were partially stabilized and one fully stabilized were investigated. The optical properties in terms of surface gloss, translucency parameter, and contrast ratio were determined via a reflection spectrophotometer at variable thicknesses, coloring, sintering method, and after immersion in an acidic environment. Light cure irradiance and radiant exposure were quantified through the specimens at variable thicknesses and the degree of conversion of two dual-cure cements was determined via Fourier Transform Infrared spectroscopy. Bi-axial flexural strength was evaluated to compare between the partially and fully stabilized zirconia prepared using different coloring and sintering methods. Surface characterization was performed using a scanning electron microscope and a spinning disk confocal microscope. The surface gloss and translucency of the zirconia investigated were brand and thickness dependent with the translucency values decreasing as the thickness increased. Staining decreased the translucency of the zirconia and enhanced surface gloss as well as the flexural strength of the fully stabilized zirconia but had no effect on partially stabilized zirconia. Immersion in a corrosive acid increased surface gloss and decreased the translucency of some zirconia brands. Zirconia thickness was inversely related to the amount of light irradiance, radiant exposure, and degree of monomer conversion. Type of sintering furnace had no effect on the optical and mechanical properties of zirconia. Monolithic zirconia maybe classified as a semi-translucent material that is well influenced by the thickness, limiting its use in the esthetic zones. Conventional acid-base reaction, autopolymerizing and dual-cure cements are recommended for its cementation. Its desirable mechanical properties give it a high potential as a restoration for posterior teeth. However, close monitoring with controlled clinical studies must be determined before any definite clinical recommendations can be drawn.

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The interior layered deposit (ILD) in Ganges Chasma, Valles Marineris, is a 4.25 km high mound that extends approximately 110 km from west to east. The deposition, deformation, and erosion history of the Ganges ILD records aids in identifying the processes that formed and shaped the Chasma. To interpret structural and geomorphic processes acting on the ILD, multiple layer attitudes and layer thickness transects were conducted on the Ganges ILD. Mineralogical data was analyzed to determine correlations between materials and landforms. Layer thickness measurements indicate that the majority of layers are between 0.5 m and 4 m throughout the ILD. Three major benches dominate the Ganges ILD. Layer thicknesses increase at the ILD benches, suggesting that the benches are formed from the gradual thickening of layers. This indicates that the benches are depositional features draping over basement topography. Layer attitudes indicate overall shallow dips generally confined to a North-South direction that locally appear to follow bench topography. Layering is disrupted on a scale of 40 m to 150 m in 12 separate locations throughout the ILD. In all locations, underlying layering is disturbed by overlying folded layers in a trough-like geometry. These features are interpreted to have formed as submarine channels in a lacustrine setting, subsequently infilled by sediments. Subsequently, the channels were eroded to the present topography, resulting in the thin, curved layering observed. Data cannot conclusively support one ILD formation hypothesis, but does indicate that the Ganges ILD postdates Chasma formation. The presence of water altered minerals, consistently thin layering, and layer orientations provide strong evidence that the ILD formed in a lacustrine setting.

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Chart of calculations regarding quarrying, cutting, transportation and cement, n.d.

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A simple, effective and inexpensive fiber optic sensor for investigating the setting characteristics of various grades of cement is described. A finite length of unsheathed multimode optical fiber laid inside the cement mix, is subjected to stress during the setting process. The microbends created on the fiber due to this stress directly influence the intensity of light propagating through the fiber. Continuous monitoring of such variations in the light output transmitted through the fiber gives a clear measure of the setting characteristics of the cement mix, thus providing a simple and elegant technique of great practical importance in the field of civil engineering. The smart fiber optic sensor described above can be incorporated into a building during the construction process itself so that continuous monitoring of the deterioration process for the entire life time of the building can be carried out.

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Research in the field of polymer modified cement has been carried out for the last 70 years or more. Polymers are mostly used to enhance durability and sustainability of cement concrete and in combination with classical construction materials a synergistic effect is obtained. In this work different polymers were added to Portland cement in various proportions and the mechanical and chemical resistance properties of the resultant composites when exposed to chemical environments were studied. Microstructural studies were also carried out to investigate the morphology of the composite and analyse the nature of interactions taking place between the cement and polymer phases. Though most polymers did not improve the compressive strength of the cement paste, it was found that they enhanced the resistance of the virgin cement paste to external chemical environments. The polymers seal the pores in the cement matrix and bridge the microcracks within the composite. Some of the polymers underwent chemical interactions with the cement paste thereby interfering in the hydration of cement. Polymers also decreased the leachability of water soluble components of virgin cement resulting in composites having improved durability. An attempt to correlate the structure of the polymers with the properties of the resultant composites is also presented.