Diffusion tensor imaging analysis of optic radiation using readout-segmented echo-planar imaging
Journal ArticlePurpose
To investigate the diffusion tensor imaging parameters of the optic radiation and surrounding structures using the high-resolution readout-segmented diffusion tensor imaging method.
Materials and methods
Coronal readout-segmented diffusion tensor images were acquired in 15 healthy volunteers. On three slices of each image, eigenvalue 1, fractional anisotropy, radial diffusivity, apparent diffusion coefficient, and signal intensity on T2-weighted images were measured in the lateral inferior longitudinal fasciculus, external and internal layers of the optic radiation, and the tapetum within regions of interest delineated by two independent observers. Profile curve analysis of regions of interest across the optic radiation and surrounding structures was performed for a representative typical case.
Results
Significant differences in fractional anisotropy, radial diffusivity and apparent diffusion coefficient were observed between external and internal layers of the optic radiation, while there was no significant difference in eigenvalue 1. In fractional anisotropy maps, two low signal bands were observed between the inferior longitudinal fasciculus, the optic radiation and the tapetum. Profile curve analysis showed a minimum on the fractional anisotropy and eigenvalue 1 images and a maximum in the radial diffusivity image.
Conclusion
Readout-segmented diffusion tensor imaging revealed significant differences in the diffusion tensor imaging parameters between internal and external layers of the optic radiation.
TAHA M Mehemed, (12-2014), Surgical and Radiologic Anatomy: Springer Nature, 36
The expression and activity of antioxidant enzymes in the liver of rats exposed to high-fructose diet in the period from weaning to adulthoo
PhD ThesisAbstract
BACKGROUND: Increased fructose consumption correlateswith rising prevalence of variousmetabolic disorders, some of which
were linked to oxidative stress. The relationship between fructose consumption and oxidative stress is complex and effects of
a fructose-rich diet on the young population have not been fully elucidated. The aim of this study was to investigate whether
high-fructose diet applied in the period from weaning to adulthood induces oxidative stress in the liver, thus contributing to
induction or aggravation of metabolic disturbances in later adulthood. To that end we examined the effects of high-fructose
diet on expression and activity of antioxidant enzymes, markers of lipid peroxidation and protein damage in the liver as the
main fructose metabolizing tissue.
RESULTS: High-fructose diet increased only SOD2 (mitochondrial manganese superoxide dismutase) activity, with no effect on
other antioxidant enzymes, lipid peroxidation or accumulation of damaged proteins in the liver.
CONCLUSION: The results show that fructose-induced metabolic disturbances could not be attributed to oxidative stress, at
least not at young age. The absence of oxidative stress in the liver observed herein implies that young organisms are capable of
maintaining redox homeostasis when challenged by fructose-derived energy overload.
Alhadi Mohamed Ali Jelban, (11-2014), Serbian national center for biological research: journal of the science of food and agriculture,
Thermal stability, AC electrical conductivity and dielectric properties of N-(5-{[antipyrinyl-hydrazono]-cyanomethyl}-[1,3,4]thiadiazol-2-yl)-benzamide Author links open overlay panel
Journal ArticleA novel organic compound containing antipyrine and thiadiazole moieties, N-(5-{[antipyrinyl-hydrazono]-cyanomethyl}-[1,3,4]thiadiazol-2-yl)-benzamide (ACTB) has been synthesized. The thermal properties, alternating current electrical conductivity (σAC) and electrical modulus of ACTB have been reported. The thermal properties were analyzed using differential scanning calorimetry and thermogravimetric measurements. The AC measurements of bulk ACTB were performed in frequency range 100 Hz–5 MHz and temperature range 303–503 K. The frequency dependence of AC conductivity is found to follow Jonscher’s universal power law with the applicability of the correlated barrier hopping model. The temperature dependence of σAC could be described in terms of Arrhenius relation with two activation energies. The activation energy decreases with increasing frequency. The dielectric relaxation behavior is explained in terms of electric modulus formalism. At relatively higher temperatures, the imaginary modulus spectra exhibit asymmetric maxima with peak-width much broader than that of the Debye peak and are skewed toward the high frequency sides of the maxima with increasing temperature. The relaxation time is calculated and exhibited thermally activated process with activation energy of 0.77 eV.
Hagar Hussien Hussien Nawar, (10-2014), Journal of alloys and compounds: Elsevier, -610
Earnings Management and Corporate Social Responsibility: The Case of UK
PhD ThesisThe primary focus of this study is to investigate the relation between Earnings Management (EM) and Corporate Social Responsibility (CSR) in the UK. While there are few studies in the existing literature that examined the relationship between EM and CSR, there is a lack of studies examining this relation in the UK. Furthermore, the existing academic literature appears to provide inconsistent results.
These considerations motivate this study to bridge this gap in the literature by providing evidence of whether or not EM and CSR are related in the UK. The present study carried out through three empirical stages based on the data obtained from the FTSE 350 Index between 2008 and 2010.
The first stage examined the EM practice using three EM models to estimate discretionary accruals as proxy for EM. The models were the Jones (1991), modified Jones (Dechow et al. 1995) and performance - matched (Kothari et al. 2005) models.
Firstly, these models were tested using multivariate analysis; the findings revealed that the performance - marched model has been identified as the model that could most accurately measure the presence of EM. Secondly, by applying univariate analysis, the study has found insignificant differences between the high and low EM practices in UK firms and that the highest and the lowest levels of EM were in 2008. Similar results were discovered when comparing the differences between income - increasing and income - decreasing EM.
The second stage tested CSR by applying both content analysis and disclosure index approaches to identify the level of Corporate Social Responsibility Disclosure (CSD) as proxy of CSR. The findings from the content analysis revealed that the employees (EMP) theme had the highest level of CSR information, followed by community (COM), environment (ENV), others (OTH), products and services (PRO), and customers (CUS). Similar results were obtained when the disclosure index approach was employed.
The relationship between EM and CSR was tested in the final stage by using univariate and multivariate analyses. The findings revealed that firms with more CSR information reported lower EM. Further tests were performed to investigate the link between EM and CSR themes and the findings revealed that firms with more information of EMP, COM, EVE and PRO reported lower EM. However, no evidence suggested that CUS and OTH information affect EM. Overall, the findings suggest that the level of CSR improve financial reports’ quality. This study aspires to contribute to our understanding and knowledge on the issue related to the role of CSR regarding the quality of reported earnings.
Yousf Ebrahem Abolgasem Almahrog, (09-2014), University of Central Lancashire: University of Central Lancashire,
Long-term fructose-enriched diet introduced immediately after weaning does not induce oxidative stress in the rat liver
Journal ArticleIncreased fructose consumption is correlated with the rising prevalence of obesity, metabolic
syndrome, and type 2 diabetes. It is believed that reactive oxygen species contribute to the
development and progression of metabolic disturbances, especially those associated with
insulin resistance. Dietary fructose produces both pro-oxidative and antioxidative effects,
depending upon the experimental conditions, dosage, duration of treatment, and
pathophysiological milieu. The effects of fructose overconsumption on young populations,
which have an increased risk of developing metabolic disorders in adulthood, have not been
fully elucidated.Wehavepreviously shownthat rats subjected toa long-termfructose-enriched
diet immediately after weaning display impaired hepatic insulin sensitivity. In this study, we
tested the hypothesis that long-term fructose consumption induces alterations in the redox
setting of the liver. Starting fromthe 21st day after birth,maleWistar ratsweremaintained for 9
weeks on a standard diet (control) or a fructose-enriched diet that consisted of standard food
and 10%fructose solution instead of drinkingwater. The expression and activity of antioxidant
enzymes aswell as lipid peroxidation and protein damagemarkersweremeasured. The results
showed that a fructose-enriched diet led to an increased expression of mitochondrial
manganese superoxide dismutase but did not affect antioxidant enzymes activity, lipid
peroxidation, thiol content, and the level of protein oxidation. Therefore, our results suggest
that the decrease in hepatic insulin sensitivity that was previously observed in rats that were
kept on the same diet regimemight be attributed to molecular mechanisms other than redox
disbalance. A possible fructose-related micronutrient deficiency should be examined.
- © 2014 Elsevier Inc. All rights reserved.
Alhadi Mohamed Ali Jelban, (09-2014), Serbian national center for biological research: Elsevier, 34
EFFECT OF PYROLYSIS ON SHRINKAGE PROPERTIES OF SU-8 POLYMER
Master ThesisAbstract
SU-8 has drawn a lot of attention during the last decades due to its promising mechanical and electrical properties. Extensive research regarding the mechanical properties of negative photoresists SU-8 has been carried out during the last decades. A lot of effort has been put into developing methods to properly characterize features such as effect of pyrolysis temperature and the pyrolysis time on shrinkage properties and morphology of SU-8. In this work photo patterned SU-8 were fabricated on silicon wafers by spin process for different speed steps (step (1) 250rpm and time 10sec, step (2) 450rpm and time 30sec, step (3) 0rpm and time 5sec), then Soft baked at 95°C for 4min before cooling for 10min. Exposure to ultraviolet (UV) light was necessary to obtain the shape of the mask, increase crosslinking degree in the irradiated areas and stabilizes them against the action of solvents during development step. The density of UV used was 6 mW/cm2 at 365 nm and exposure time was 5min, while the volume of SU-8 developer was 40cm3 at 10min. Samples were cut into 2cmx2cm dimensions. The pyrolysis was carried out in a closed quartz tube furnace in an inert nitrogen gas (N2) flow at 1500 standard cubic centimeters per minute (SCCM) and different parameter of temperature (350oC, 400oC, 450oC and 500oC) and time (10min and 20min). Peeling of the SU-8 occurs due to a poor adhesion of the resist to the substrate, thicker films or faster heating rates during the pyrolysis of SU-8. Increasing pyrolysis parameters (temperature and time) lead to larger vertical and horizontal shrinkage, lower sheet resistivity and roughness. The scanning electron microscope (SEM), atomic force microscopy (AFM) and profilometer were used to examine the shrinkage and roughness of SU-8, in order to gain an understanding of how it can affect the shrinkage properties and determine the optimized pyrolysis conditions.
Waled Ashor Mftah Galy, (08-2014), جامعة برليس الماليزية: University Malaysia Perlise,
Exploitation survey of sea water in agriculture of coastal deserts in Libya
Journal ArticleThis paper examines the possibility of exploitation sea water in the agriculture of coastal deserts in Libya, some of which salt-tolerant plants (Halophyte), especially that used to feed animals, and convert marshes coastal useless life to nature reserves attract many kinds of migratory birds and marine lives after the cultivation of these marshes by type of plants, which grow in saltwater. In other words this paper will present a study of how to use the seawater as a renewable resource for agriculture in Libya and how this will contribute in sustainable development in this sprawling country. The advantage of this resource can be taken to fill up the gap of natural grassland and the growing demand for animal feed which has caused rising prices of livestock and meats, not to mention the tribal conflicts that occur because of the dispute over grasslands. The most significant reasons that force us to exploit the seawater are:(1) Lack of inventory of underground water in the coastal areas and overlapping with seawater in several areas. In contrast, Libya has the longest coastline on the Mediterranean with a length of more than 1,900 kilometers;(2) Fluctuation rate of the amount of rainfall, which has affected negatively on the natural grassland;(3) More than 90% of the country's population in the coastal areas, that causing a large drain of groundwater which already meager in this region, for this reason the government has worked to establish Artificial River project, which delivers water from the south to the northern areas to reduce this problem, and (4) Depletion and degradation of natural grassland is largely due to overgrazing.
Mohamed Nasar, (06-2014), بلغراد، صربيا: International Academy of Ecology and Environmental Sciences (IAEES, 2
Dynamic oxygen-enhanced MRI of cerebrospinal fluid
Journal ArticleOxygen causes an increase in the longitudinal relaxation rate of tissues through its T1-shortening effect owing to its paramagnetic properties. Due to such effects, MRI has been used to study oxygen-related signal intensity changes in various body parts including cerebrospinal fluid (CSF) space. Oxygen enhancement of CSF has been mainly studied using MRI sequences with relatively longer time resolution such as FLAIR, and T1 value calculation. In this study, fifteen healthy volunteers were scanned using fast advanced spin echo MRI sequence with and without inversion recovery pulse in order to dynamically track oxygen enhancement of CSF. We also focused on the differences of oxygen enhancement at sulcal and ventricular CSF. Our results revealed that CSF signal after administration of oxygen shows rapid signal increase in both sulcal CSF and ventricular CSF on both sequences, with statistically significant predominant increase in sulcal CSF compared with ventricular CSF. CSF is traditionally thought to mainly form from the choroid plexus in the ventricles and is absorbed at the arachnoid villi, however, it is also believed that cerebral arterioles contribute to the production and absorption of CSF, and controversy remains in terms of the precise mechanism. Our results demonstrated rapid oxygen enhancement in sulcal CSF, which may suggest inhaled oxygen may diffuse into sulcal CSF space rapidly probably due to the abundance of pial arterioles on the brain sulci.
Taha M Mehemed, (06-2014), PLoS One: Public Library of Science, 9
Visualization of Lenticulostriate Arteries at 3T: Optimization of Slice-selective Off-resonance Sinc Pulse–prepared TOF-MRA and Its Comparison with Flow-sensitive Black-blood MRA
Journal ArticleRationale and Objectives
To optimize visualization of lenticulostriate artery (LSA) by time-of-flight (TOF) magnetic resonance angiography (MRA) with slice-selective off-resonance sinc (SORS) saturation transfer contrast pulses and to compare capability of optimal TOF-MRA and flow-sensitive black-blood (FSBB) MRA to visualize the LSA at 3T.
Materials and Methods
This study was approved by the local ethics committee, and written informed consent was obtained from all the subjects. TOF-MRA was optimized in 20 subjects by comparing SORS pulses of different flip angles: 0, 400°, and 750°. Numbers of LSAs were counted. The optimal TOF-MRA was compared to FSBB-MRA in 21 subjects. Images were evaluated by the numbers and length of visualized LSAs.
Results
LSAs were significantly more visualized in TOF-MRA with SORS pulses of 400° than others (P < .003). When the optimal TOF-MRA was compared to FSBB-MRA, the visualization of LSA using FSBB (mean branch numbers 11.1, 95% confidence interval (CI) 10.0–12.1; mean total length 236 mm, 95% CI 210–263 mm) was significantly better than using TOF (4.7, 95% CI 4.1–5.3; 78 mm, 95% CI 67–89 mm) for both numbers and length of the LSA (P < .0001).
Conclusions
LSA visualization was best with 400° SORS pulses for TOF-MRA but FSBB-MRA was better than TOF-MRA, which indicates its clinical potential to investigate the LSA on a 3T magnetic resonance imaging.
TAHA M Mehemed, (06-2014), Academic Radiology: Elsevier, 21
Acute mercury toxicity modulates cytochrome P450, soluble epoxide hydrolase and their associated arachidonic acid metabolites in C57Bl/6 mouse heart
Journal ArticleMercury exposure is associated with increased risk of cardiovascular disease and profound cardiotoxicity. However, the correlation between Hg(2+)-mediated toxicity and alteration in cardiac cytochrome P450s (Cyp) and their dependent arachidonic acid metabolites has never been investigated. Therefore, we investigated the effect of acute mercury toxicity on the expression of Cyp-epoxygenases and Cyp-ω-hydroxylases and their associated arachidonic acid metabolites in mice hearts. In addition, we examined the expression and activity of soluble epoxide hydrolase (sEH) as a key player in arachidonic acid metabolism pathway. Mercury toxicity was induced by a single intraperitoneal injection (IP) of 2.5 mg/kg of mercuric chloride (HgCl₂). Our results showed that mercury treatment caused a significant induction of the cardiac hypertrophy markers, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP); in addition to Cyp1a1, Cyp1b1, Cyp2b9, Cyp2b10, Cyp2b19, Cyp2c29, Cyp2c38, Cyp4a10, Cyp4a12, Cyp4a14, Cyp4f13, Cyp4f15, Cyp4f16 and Cyp4f18 gene expression. Moreover, Hg(2+) significantly increased sEH protein expression and activity levels in hearts of mercury-treated mice, with a consequent decrease in 14,15-, and 11,12-epoxyeicosatrienoic acids (EETs) levels. Whereas the formation of 14,15-, 11,12-, 8,9-dihydroxyeicosatrienoic acids (DHETs) was significantly increased. In conclusion, acute Hg(2+) toxicity modulates the expression of several Cyp and sEH enzymes with a consequent decrease in the cardioprotective EETs which could represent a novel mechanism by which mercury causes progressive cardiotoxicity. Furthermore, inhibiting sEH might represent a novel therapeutic approach to prevent Hg(2+)-induced hypertrophy.
Issa Emhemmed Alemyani Amara, (04-2014), Toxicology Letters: Elsevier, 219