770 research outputs found
Histomorphological investigation of Liza aurata (Risso, 1810) (Mugilidae) ovary in the late oogenesis in the Caspian Sea
In the present study, various developmental stages of Liza aurata oocyte, especially IV and V stages have been described. On the basis of histological investigations, oocyte development in L. aurata comprises immature (I), the early maturing (II), the late maturing (III), mature (IV), ripe (V), and spent (VI) stages. In the stages I and II, nucleus occupied a large volume of oocyte. Vacuolization and vitellogenesis appearance started at stage III. Vitellogenesis increased by further growth of oocyte at stage IV and also vacuolization occurred. Zona radiata and follicular cells were more conspicuous at this stage. In the late stage IV, the number of vacuoles decreased due to the fusing of small vacuoles and nucleoli located on different places of the nucleus at this stage. At stage V, oocyte normally possessed one or two oil droplets; nucleus disappeared after migration to animal pole. Recently spawned oocytes were fluid, lemon in color and 779.2µm in diameter. The maximum gonadosomatic index (GSI) value was found at stage V
Assessing the optimum temperature for survival, growth and reproduction of adult Caspian Sea Pontogammarus maeoticus
This study was conducted to assess the effect of different levels of temperature on survival, growth and reproduction of adult Caspian Sea Pontogammarus rnaeoticus. Temperature effects were studied in 5 thermal levels (15, 20, 25, 30 and 35°C) where salinity was constant (7.1±0.2ppt). The sampling was made from Hassan-nrud coastal area in Guilan province. The results showed that survival was maximum at 20CC (95.56%) with higher temperatures showing a significant descending trend in survival (P<0.05) in which all samples perished on I 8th day at 35°C treatment. The number of produced brood followed a significant ascending , trend from 15°C to 25°C treatments and reached its climax at 25°C (117.3+12.2 broods). The minimum value for produced brood was reported at 15°C treatment (21.3±2.4 broods). A significant persistent increment of growth rate was observed throughout all treatments (P<0.05) where the maximum and minimum values were observed for the final (5.76±0.1mm) and the first (1.77±0.06mm) treatments, respectively. We suggest 25°C, 20°C and 30°C temperature treatments for producing the maximum brood per unit of time, the highest survival rate and the maximum growth, respectively. The temperature 25°C is defined as the best for aquaculture of pontogammarus as livefood of aquatic organisms
In situ visualization of Ni-Nb bulk metallic glasses phase transition
We report the results of the Ni-based bulk metallic glass structural
evolution and crystallization behavior in situ investigation. The X-ray
diffraction (XRD), transmission electron microscopy (TEM), nano-beam
diffraction (NBD), differential scanning calorimetry (DSC), radial distribution
function (RDF) and scanning probe microscopy/spectroscopy (STM/STS) techniques
were applied to analyze the structure and electronic properties of Ni63.5Nb36.5
glasses before and after crystallization. It was proved that partial surface
crystallization of Ni63.5Nb36.5 can occur at the temperature lower than for the
full sample crystallization. According to our STM measurements the primary
crystallization is originally starting with the Ni3Nb phase formation. It was
shown that surface crystallization drastically differs from the bulk
crystallization due to the possible surface reconstruction. The mechanism of
Ni63.5Nb36.5 glass alloy 2D-crystallization was suggested, which corresponds to
the local metastable (3x3)-Ni(111) surface phase formation. The possibility of
different surface nano-structures development by the annealing of the
originally glassy alloy in ultra high vacuum at the temperature lower, than the
crystallization temperature was shown. The increase of mean square surface
roughness parameter Rq while moving from glassy to fully crystallized state can
be caused by concurrent growth of Ni3Nb and Ni6Nb7 bulk phases. The simple
empirical model for the estimation of Ni63.5Nb36.5 cluster size was suggested,
and the obtained values (7.64 A, 8.08 A) are in good agreement with STM
measurements data (8 A-10 A)
Modelling sustainable development of oil and petrochemical industries in Southwest coastal zones of Iran
Evaluation of Aloe vera (Aloe barbadensis Miller) Antioxidant Activity and Some of the Morphological Characteristics in Different Vermicompost Field
Construction and function of effective substances of medicinal plants are influenced by environmental factors such as deficiency or increased of nutrients in the soil and substrates. Therefore, a greenhouse experiment was performed in completely randomized design with four treatments and three replications. The effects of vermicompost were examined on the morphological and phytochemical features in aloe vera. Treatments consisted of four vermicompost percentages ( , , and ) in humus soil. The considered factors were leaf weight, gel fresh weight, gel dry weight, the antioxidant capacity of the gel, glucomannan of gel, flavonoids and phenols of gel, and anthocyanins of cortex. data analysis showed that the maximum of leaf weight, gel weight, dry weight of gel and gel glucomannan was obtained in of vermicompost. The maximum of gel phenol, antioxidant activity of gel and anthocyanins of cortex belonged to of vermicompost and gel flavonoid in of vermicompost. To achieve maximum antioxidant capacity and optimum amount of active substances, more studies and application of different field of vermicompost are required in order to increase the value of medicinal properties
Association between vitamin A and E and apolipoprotein A and B levels in type 2 diabetes
Objective. To determine the relationship between serum vitamin A and E and apolipoprotein levels in type 2 diabetic patients. Setting. Shariati Hospital, Tehran, Iran. Subjects and methods. One hundred and seventeen eligible type 2 diabetic patients who attended the Endocrine Research and Metabolism Center between 2002 and 2004 were enrolled in the study. Blood samples were collected after a 12 - 14-hour overnight fast for the measurement of serum levels of total cholesterol, triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL), apolipoprotein (apo) A1 and apoB, and vitamins A and E. Anthropometric indices were determined by physical examination. Data were analysed statistically using Pearson's coefficient, multiple regression, and partial and bivariate correlations. Results. The mean body mass index (BMI) of the subjects was 27.4 ± 3.7 kg/m2. The mean (± standard deviation (SD)) serum levels of vitamins A and E were 0.5 ± 0.1 μg/ml and 9.5 ± 2.6 μg/ml, respectively. There were no significant differences in the plasma levels of vitamins A and E in males and females. Mean serum levels of vitamins A and E were within the normal range for both sexes. Serum lipid levels (total cholesterol, triglyceride and apoB) correlated with serum levels of vitamin E (p < 0.05). Serum levels of vitamins A and E were also correlated (p < 0.05). Standardised vitamin E levels showed significant negative correlation with most studied lipid profiles (p < 0.05). Conclusion. This study found that mean serum levels of the natural antioxidants vitamin E, and especially vitamin A, were close to the lower end of the normal range of these antioxidants in type 2 diabetics. Also, serum vitamin E and standardised vitamin E levels were important predictors of serum apoA1 levels in these patients. South African Journal of Clinical Nutrition Vol. 19(1) 2006: 39-4
Thermomechanical couplings in shape memory alloy materials
In this work we address several theoretical and computational issues which are related to the thermomechanical modeling of shape memory alloy materials. More specifically, in this paper we revisit a non-isothermal version of the theory of large deformation generalized plasticity which is suitable for describing the multiple and complex mechanisms occurring in these materials during phase transformations. We also discuss the computational implementation of a generalized plasticity based constitutive model and we demonstrate the ability of the theory in simulating the basic patterns of the experimentally observed behavior by a set of representative numerical examples
Corrosion behaviour of porous Ti intended for biomedical applications
Porous Ti implants are being developed inorder to reduce the biomechanical mismatch between theimplant and the bone, as well as increasing the osseointegrationby improving the bone in-growth. Most of the focusin the literature has been on the structural, biological andmechanical characterization of porous Ti whereas there islimited information on the electrochemical characterization.Therefore, the present work aims to study the corrosionbehaviour of porous Ti having 30 and 50 % ofnominal porosity, produced by powder metallurgy routeusing the space holder technique. The percentage, size anddistribution of the pores were determined by image analysis.Electrochemical tests consisting of potentiodynamicpolarization and electrochemical impedance spectroscopywere performed in 9 g/L NaCl solution at body temperature.Electrochemical studies revealed that samples presenteda less stable oxide film at increased porosity, morespecifically, the complex geometry and the interconnectivityof the pores resulted in formation of less protectiveoxide film in the pores.This study was supported by FCT with the
reference project UID/EEA/04436/2013, by FEDER funds through
the COMPETE 2020 – Programa Operacional Competitividade e
Internacionalizac¸a˜o (POCI) with the reference project POCI-01-0145-
FEDER-006941, Programa de Acc¸o˜es Universita´rias Integradas LusoFrancesas’
(PAUILF TC-12_14), and The Calouste Gulbenkian
Foundation through ‘‘Programa de Mobilidade Acade´mica para Professores’’.
The authors would also like to acknowledge Prof. Ana
Senos (University of Aveiro) and Prof. Jose´ Carlos Teixeira
(University of Minho) for the provision of the characterization
facilities.info:eu-repo/semantics/publishedVersio
Estimating the completeness of gastric cancer registration in Ardabil/Iran by a capture-recapture method using population-based cancer registry data
Background: Knowledge of cancer incidences is essential for cancer prevention and control programs. Capture-recapture methods have been recommended for reducing bias and increasing the accuracy of cancer incidence estimations. This study aimed to estimate the completeness of gastric cancer registration by the capture-recapture method based on Ardabil population-based cancer registry data. Materials and Methods: All new cases of gastric cancer reported by three sources, pathology reports, death certificates and medical records that reported to Ardabil population-based cancer registry in 2006 and 2008 were enrolled in the study. The duplicate cases based on the similarity of first name, surname and fathers names were identified between sources. The estimated number of gastric cancers was calculated by the log-linear method using Stata 12 software. Results: A total of 857 new cases of gastric cancer were reported from three sources. After removing duplicates, the reported incidence rates for the years 2006 and 2008 were 35.3 and 32.5 per 100,000 population, respectively. The estimated completeness calculated by log-linear method for these years was 36.7 and 36.0, respectively. Conclusions: These results indicate that none of the sources of pathology reports, death certificates and medical records individually or collectively fully cover the incident cases of gastric cancer. We can obtain more accurate estimates of incidence rates using the capture-recapture method
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