193 research outputs found
High pressure solid state chemistry of C-N-H and Ti-N systems
This thesis presents the use of molecular precursors for the synthesis of
solid-state materials through the application of extreme conditions. The main
tool for the exploration of these materials was the diamond anvil cell which
generated static pressures of up to 85 GPa. Combined with the use of highpower
lasers, it provides a powerful and efficient technique for high-pressurehigh-
temperature synthesis of solid-state materials. The work presented here is
an investigation into the synthesis and recovery of new materials within two
solid-state systems, C-N-H and Ti-N-O. Crystallographic analysis of these
systems is a challenging process, made more difficult by their relatively light
elemental composition and the use of the diamond anvil cell. In both cases a
systematic experimental and analytical strategy was adopted to enable the
extraction of the best data possible, both qualitatively and statistically.
Two C-N-H systems were investigated: C2N3H and C6N9H3.HCl.
Synchrotron X-ray diffraction and Raman scattering data are reported for the
new dense tetrahedrally bonded phase C2N3H with a defective wurtzite structure.
This is synthesised by laser heating from an organic precursor, dicyandiamide,
C2N4H4 at high-pressure in a diamond anvil cell. This work confirms the
structure deduced in previous work from electron diffraction experiments on
samples recovered to ambient conditions.
The graphitic layered compound C6N9H3.HCl was subjected to pressures
up to 70 GPa in a diamond anvil cell and its structural behaviour was examined
using synchrotron X-ray diffraction. The use of laser heating experiments
revealed the synthesis of a new carbon nitride phase which is recoverable to
ambient conditions.
The second group of systems explored was those based on Ti-O-N.
Amorphous or nano-crystalline precursors were used to attempt the synthesis of
Ti3N4. The high-pressure and temperature behaviour of these materials was
examined using synchrotron X-ray diffraction and Raman spectroscopy, in a
laser-heated diamond anvil cell.
In addition, the high-pressure studies of Ti2.85O4N, a recently discovered
titanium oxynitride phase, are reported here up to 70 GPa. Using synchrotron
angle dispersive techniques two high-pressure phases are observed and an
attempt to elucidate these structures are reported
Quantitative determination of aflatoxin by high performance liquid chromatography in wheat silos in Golestan province, north of Iran
Background: Aflatoxins are the most common mycotoxins that contaminate crops. They are produced by fungi such as Aspergillus flavus and Aspergillus parasiticus. Wheat (Tricitumaestivum) is one of the most important staple foods used in Iran, and the environmental conditions in the north of Iran are favorable to fungal growth. This study was designed in order to determine the aflatoxin concentration in wheat samples from silos in Golestan Province north of Iran. Methods: Samples were collected from three silos of Golestan province. First, aflatoxins were isolated using immu-noaffinity chromatography. Then the aflatoxin concentrations were determined by High performance liquid chroma-tography (HPLC) method and fluorescence detector. Results: Ten out of 34 samples (29.4 of samples) were contaminated by aflatoxins.No concentration was found above permitted aflatoxin levels in Iran (15 ng/g). In one sample (2.9), aflatoxin B1 was seen over the permissible limits in Iran. The highest level found in samples for total aflatoxin, aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatox-in G2 were 7.08 ng/g, 6.91 ng/g, 0.29 ng/g, 1.37 ng/g and 0.23 ng/g, respectively. No correlation was found between humidity levels in wheat samples contained aflatoxin and wheat samples without aflatoxin. Conclusion: Despite the total aflatoxins determined in samples were below the permissible limits in Iran, the 29 aflatoxin contamination rate can negatively affect health factors and it should not be neglected. So, it is predictable that if the storage duration of samples increases, the aflatoxin contamination levels will increase. Ā© 2015, Iranian Journal of Public Health. All rights reserved
Seasonal change of thyroid histomorphological structure and hormone production in yellowfin seabream (Acanthopagrus latus) in the Persian Gulf
Seasonal changes of the thyroid gland structure and hormones secretion was examined in yellowfin seabream (Acanthopagrus latus) in the northwest of Persian Gulf (Musa creek). Thyroid gland composed of follicles scattered around the ventral aorta, near the gills. Follicular cells varied according to secretion of the gland during warm and cold seasons. Thyroid hormones (Triidothyronine [T3] and Thyroxine [T4]) were detected in the fish serum in levels ranged from 4.09-1.30 ng/mL for T3 and from 1.10-0.21 ng/mL for (T4) in the warm and cold seasons, respectively. The results showed that the height of thyroid epithelium and plasma concentration of thyroid hormones (thyroid activity) in A. latus increased significantly during spring and summer. The peak of these factors occurred in midsummer (August). Then, the thyroid activity decreased significantly during autumn and early winter from October to December according to decrease of temperature. T3 and T4 increased significantly from January to April
Isolation of common carp ovarian follicular cells and evaluation of their endocrine activity in primary cell culture
To study viability and activity of isolated common carp, Cyprinus carpio, ovarian follicular cells (granulosa and theca cells), 17-Ī±-Hydroxy progesterone (17Ī±-OHP) and 17Ī²-Estradiol (E2) levels were estimated in the culture media of cultivated carp ovarian follicular cells, using radioimmunoassay (RIA). Oocytes were isolated from the ovaries of female carp. Interstitial tissue was manually removed in order to obtain single oocytes surrounded only by the follicular envelope. Such a preparation was trypsinized at room temperature. Follicular cell suspension contained both cells and cell clumps. It was the mixture of theca (T) and granulosa (G) cells. The cells were grown as monolayer in 24-well microplates in M199 medium supplemented with FBS. Culture media were analyzed for estrogen and progesterone content by appropriate radioimmunoassay. Trypsinization of ovarian follicles resulted in the formation of the cell suspension which contained a mixture of G and T cells. The follicular cells attached to glass and grew well during culture period. E2 was the main steroid hormone secreted by cultivated cells. Estrogen secretion increased by 415.52 Ā± 25 pg/ml at the first 3 days up to 530.25 Ā± 55.8 pg/ml on day 5 and it didn't change significantly until the end of the experiment. 17Ī±-OHP secretion, however, gradually increased from 23.84 Ā± 8.2 pg/ml at the beginning of culture up to 35.76 Ā± 5.4 pg/ml at the end of cultivating. As the result of the present study the fish follicular cells grown in tissue culture were steroidogenically active cells as expressed by the secretion of E2 and P4 and the E2 was a dominant hormone secreted by isolated follicular cells, which it correlated closely with vitellogenes stage
Recommended from our members
Acceptance and commitment therapy as an adjunct to the MOVE! programme: a randomized controlled trial.
ObjectiveThe current study tested the efficacy of an acceptance and commitment therapy (ACT) group intervention for disinhibited eating behaviour as an adjunct to the Veterans Affairs MOVE!Ā© weight management programme.MethodsVeterans (N = 88) with overweight or obesity who completed the MOVE! weight management programme and self-identified as having problems with 'stress-related eating' were randomized to four 2-h weekly ACT sessions or a continued behavioural weight-loss (BWL) intervention. Assessments were completed at baseline, post-treatment and 3- and 6-month follow-up on outcomes of interest including measures of disinhibited eating patterns, obesity-related quality of life, weight-related experiential avoidance and weight.ResultsThe BWL group exhibited significantly greater reductions in binge eating behaviour at post-treatment compared with the ACT group. Significant improvements in other outcomes were found with minimal differences between groups. In both groups, decreases in weight-related experiential avoidance were related to improvements in binge eating behaviour.ConclusionsTaken together, the continued BWL intervention resulted in larger improvements in binge eating behaviour than the ACT intervention. The two groups showed similar improvements in other disinhibited eating outcomes. Future studies are encouraged to determine if more integrated or longer duration of ACT treatment may maximize eating outcomes in MOVE.Trial Registration Number: This trial was registered with ClinicalTrials.gov database (NCT01757847)
Markov modeling of moving target defense games
We introduce a Markov-model-based framework for Moving Target Defense (MTD) analysis. The framework allows modeling of broad range of MTD strategies, provides general theorems about how the probability of a successful adversary defeating an MTD strategy is related to the amount of time/cost spent by the adversary, and shows how a multi-level composition of MTD strategies can be analyzed by a straightforward combination of the analysis for each one of these strategies. Within the proposed framework we define the concept of security capacity which measures the strength or effectiveness of an MTD strategy: the security capacity depends on MTD specific parameters and more general system parameters. We apply our framework to two concrete MTD strategies
Primary culture of ovarian follicular cells of Sterlet, Acipenser ruthenus to develop an in vitro system
The aim of the present study was to develop an in vitro system for functional investigation of ovarian follicular cells in Sterlet, Acipenser ruthenus. Oocytes for the primary culture were obtained from the ovaries of a 6 years old Sterlet 729 g in weight and 47 cm in total length. The oocytes were in advanced vitellogenesis stage (PI >10). A part of the ovary (containing about 300 follicles) was removed, ovarian follicles isolated by manually removing those from the interstitial tissue and washed with sterile phosphate buffered saline (PBS) containing antibiotics and Amphotericin B. Follicular cells were separated by treating oocytes with 0.25% trypsin-EDTA in Ca2+ and Mg2+ free PBS and cultured in medium L-15 supplemented with 20% FBS, streptomycin sulphate (Gibco, 100 mg.ml-1), penicillin G potassium (Gibco, 100 IU.ml-1) and Amphotericin B (Gibco, 2.5 mg.ml-1) at 22 Ā°C. The concentrations of Testosterone (T), Estradiol-17Ī² (E2), Progesterone (P4) and 17Ī±-hydroxyprogestron (17Ī±OHP) in the medium were measured at days 3, 5 & 7 by the Enzyme-Linked Immunosorbent Assay. According to the results, the ovarian follicular cells of Sterlet proliferated in L-15 medium were steroidogenically active as expressed by the secretion of T, E2, P4 & 17Ī±OHP. Testosterone was the dominant hormone secreted by cultivated follicular cells, which was correlated closely with the end of vitellogenesis in the isolated oocytes. Decrease in production of these hormones was greater at days 3 & 4 in comparison with those at days 5 & 6. By successfully culturing ovarian follicular cells of Sterlet in L-15 culture medium, an in vitro system was developed which enables functional studies to be carried out similar to the in vivo situation in the ovarian follicles
DB-PABP: a database of polyanion-binding proteins
The interactions between polyanions (PAs) and polyanion-binding proteins (PABPs) have been found to play significant roles in many essential biological processes including intracellular organization, transport and protein folding. Furthermore, many neurodegenerative disease-related proteins are PABPs. Thus, a better understanding of PA/PABP interactions may not only enhance our understandings of biological systems but also provide new clues to these deadly diseases. The literature in this field is widely scattered, suggesting the need for a comprehensive and searchable database of PABPs. The DB-PABP is a comprehensive, manually curated and searchable database of experimentally characterized PABPs. It is freely available and can be accessed online at http://pabp.bcf.ku.edu/DB_PABP/. The DB-PABP was implemented as a MySQL relational database. An interactive web interface was created using Java Server Pages (JSP). The search page of the database is organized into a main search form and a section for utilities. The main search form enables custom searches via four menus: protein names, polyanion names, the source species of the proteins and the methods used to discover the interactions. Available utilities include a commonality matrix, a function of listing PABPs by the number of interacting polyanions and a string search for author surnames. The DB-PABP is maintained at the University of Kansas. We encourage users to provide feedback and submit new data and references
Introducing the best cell culture method for primary hepatocyte from orangespotted grouper, Epinephelus coioides
Liver is one of the most important organs in vertebrates that have important roles in detoxifying. This organ was used as a target organ in many physiological and toxicological aspects. The main purpose of the present study was developing appropriate methodology for the primary cultivation of hepatic cells from orange-spotted Grouper, Epinephelus coioides, a subtropical fish species of the family Serranidae. In present study, hepatocytes were isolated from five grouper individuals. Initially, the fish wiped with 70% ethanol. Liver were removed and cut into small pieces with scissors and hepatocytes were disconnected using different enzymatic digestion with collagenase (Type 1 and 4) and trypsin and additional nutrient materials in culturing mediums. Then, cells were cultured for 2 weeks in Lebowitz L-15 under 3 methods: 1. using enzymatic digestion by trypsin, 2. using enzymatic digestion by collagenase (type 1 and 4) and 3. Using nutrients and additives was cultured. Finally, effects of different incubation temperature (20, 25, 28, 30 and 32 degree of Celsius) and Bovine serum content (0, 10 and 20% and 20%+ITS) on cell growth were estimated. According to the results, digestion by collagenase type 4, resulted in more cell colonization and growth in comparison with other methods. At the same method, cells showed fibroblastic morphology. In conclusion, the best culture method for primary hepatocyte from orange-spotted Grouper, Epinephelus coioides, was using ITS+20%FBS under 30 degree of Celsius incubation temperature
Histological Study of gonads in Euryglossa orientalis from Persian Gulf
Among more than 600 fish species in Persian Gulf, Soles are considered as one of the most economically important species. These fish is different from other fishes in morphological, functional and structural organs and like many other flatfish are less well known. The present study was designed to investigate the histological structure of gonads of Sole (Euryglossa orientalis) in two breeding and rest seasons. 40 Sole fish were collected from Zangi estuary (located in Mussa creek in the north of Persian Gulf) in early July and early October (non- breeding and breeding seasons) 2013. After biometry, gonadal tissues were dissected and weighed to determine Gonadosomatic Index (GSI). Then fixed in Bouinās solution. Histological specimens were transported to the histological laboratory. Tissue sections were prepared according to conventional methods include dehydration, clearing and paraffin. And then were cut down to 5 micron sections and stained. These tissue sections were studied by light microscopy. The result showed that different stages of germ cells in both male and female gonads. Although in breeding season mature cells were noticed, GSI index of testis and ovary in Sole showed significant difference between the two seasons
- ā¦