1,782 research outputs found
Electrospray ionization-mass spectrometry of different extracts of the organs of Rumex cyprius and their antihepatotoxic effect
Purpose: Phytochemical and biological investigations of the valuable plant, Rumex cyprius, family Polygonaceae, wildly grown in Saudi Arabia.Methods: Chloroform, ethyl acetate and methanol extracts were prepared from the different organs of R. cyprius. The extracts were analyzed by electrospray ionization source coupled to a mass spectrometer (ESI-MS) and tandem mass spectrometer (ESI-MS/MS) at different collision energies. The plant organs (leaf, fruit and stem) were standardized on the bases of quercetin by HPLC, and determined for their hepatoprotection in tetrachloride-induced acute liver toxicity using a mouse model.Results: Twenty-five phenolic compounds distributed between the leaf, fruit and stem of R. cyprius were identified. They were related to classes of anthraquinones, phenolic acids, flavonoid aglycones, glycosides and polyphenols. Twenty-two compounds in total were found and identified, and for the hepatoprotective effects, the leaf exhibited the best activity.Conclusion: R. cyprius is a source of potentially active phytoconstituents and a good naturalhepatoprotective drug. This study is being documented for the first time
Theoretical analysis of the spatial variability in tillage forces for fatigue analysis of tillage machines
This paper presents a new theoretical model to describe the spatial variability
in tillage forces for the purpose of fatigue analysis of tillage machines. The
proposed model took into account both the variability in tillage system
parameters (soil engineering properties, tool design parameters and operational
conditions) and the cyclic effects of mechanical behavior of the soil during
failure ahead of tillage tools on the spatial variability in tillage forces. The
stress-based fatigue life approach was used to determine the life time of
tillage machines, based on the fact that the applied stress on tillage machines
is primarily within the elastic range of the material. Stress cycles with their
mean values and amplitudes were determined by the rainflow algorithm. The damage
friction caused by each cycle of stress was computed according to the Soderberg
criterion and the total damage was calculated by the Miner's law. The proposed
model was applied to determine the spatial variability in tillage forces on the
shank of a chisel plough. The equivalent stress history resulted from these
forces were calculated by means of a finite element model and the Von misses
criterion. The histograms of mean stress and stress amplitude obtained by the
rainflow algorithm showed significant dispersions. Although the equivalent
stress is smaller than the yield stress of the material, the failure by fatigue
will occur after a certain travel distance. The expected distance to failure was
found to be df=0.825Ă106km. It is concluded that the spatial variability in
tillage forces has significant effect on the life time of tillage machines and
should be considered in the design analysis of tillage machines to predict the
life time. Further investigations are required to correlate the results achieved
by the proposed model with field tests and to validate the proposed assumptions
to model the spatial variability in tillage force
Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code
AbstractThe new Egyptian Code (ECP-201:2012) introduces new vehicular live loads (VLL) and new load combinations for the design of roadway bridges. The new VLL and load combinations introduced in ECP-201:2012 are fundamentally different than those presented in previous versions of the code. The impact of these new loads and load combinations on the design of new bridges or the structural safety of the existing bridges that have been designed according to ECP-201:2003 or ECP-201:1993 has not been fully addressed for the different bridge deck systems. Three different bridge deck systems, i.e. concrete I-shaped girders, composite steel plate girders, and concrete box-girders with different spans were numerically modeled using two-dimensional grillage analogy. The bridge decks were analyzed under main gravity loads using VLL according to ECP-201:2012 and ECP-201:2003. The internal forces of individual load cases, total un-factored load combination, and total factored load combination of ECP-201:2012 and ECP-201:2003 were compared.The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections
HeII Recombination Lines From the First Luminous Objects
The hardness of the ionizing continuum from the first sources of UV radiation
plays a crucial role in the reionization of the intergalactic medium (IGM).
While usual stellar populations have soft spectra, mini-quasars or metal-free
stars with high effective temperatures may emit hard photons, capable of doubly
ionizing helium and increasing the IGM temperature. Absorption within the
source and in the intervening IGM will render the ionizing continuum of
high-redshift sources inaccessible to direct observation. Here we show that
HeII recombination lines from the first luminous objects are potentially
detectable by the Next Generation Space Telescope. Together with measurements
of the hydrogen Balmer alpha emission line, this detection can be used to infer
the ratio of HeII to HI ionizing photons. A measurement of this ratio would
shed light on the nature and emission mechanism of the first luminous sources,
with important astrophysical consequences for the reheating and reionization of
the IGM.Comment: ApJ published version. Due to an error in one of the references, the
strength of the 1640 A line was underestimated in a previous version; this
line is now brighter by a factor of 1
A cross-cultural comparison of sleep patterns between typically developing children and children with ASD living in Saudi Arabia and the United Kingdom
Background:
Sleep is crucial for child development, especially for children with ASD. While it is known that children with ASD experience more severe sleep problems and that these problems tend to persist compared to their typically developing counterparts, these findings tend to come from only Western countries. A cross-cultural study is important to understand if the prevailing understanding of sleep in children with ASD can be extended to different cultural backgrounds.
Aim:
A cross-cultural study is conducted, involving typically developing children and children with ASD aged 5â12 across two countries: Saudi Arabia and the United Kingdom.
Methods and procedures:
Using a combination of questionnaires measuring ASD severity (CARS-2), sleep quality (CSHQ), sociodemographic and lifestyle variables and sleep diaries, 244 children were sampled using a mixture of snowball and convenience sampling methods.
Outcomes and results:
Children with ASD experience more sleep problems compared to typically developing children in Saudi Arabia, and these problems similarly persist across time. Specifically, it was found that children with ASD in Saudi Arabia experience greater sleep onset latency and a greater number of night awakenings. Additionally, across the ASD groups, it was found that children from Saudi Arabia generally experienced poorer sleep than children in the United Kingdom in terms of shorter sleep duration, although children in the United Kingdom tended to report more instances of sleep anxiety and parasomnias.
Conclusions and implications:
Several reasons such as parental education about sleep hygiene, cultural influences and social hours were put forward as potential explanations for cross-cultural differences. Findings served to emphasise the importance of culturally-appropriate interventions and public education regarding child sleep
Ginger Ingredients Alleviate Diabetic Prostatic Complications: Effect on Oxidative Stress and Fibrosis
Prostatic complications are common in patients with diabetes. This study investigated the effect of different ginger ingredients: zingerone, geraniol, and 6-gingerol on the prostate in diabetic rats. Diabetes was induced in Wistar rats by streptozotocin intraperitoneal injection (50âmg/kg), and the rats were left for 10 weeks to develop prostatic complications. In diabetic treated groups, rats received daily oral zingerone, geraniol, and 6-gingerol in doses of 20, 200, and 75âmg/kg, respectively, in the last 8 weeks. Treatment with the compounds caused changes in the ventral prostate of diabetic animals as indicated by the columnar ductal epithelium and dense secretions. There was an amelioration of oxidative stress as evidenced by the lowering of prostate malondialdehyde and elevating prostate oxidized to reduced glutathione (GSH/GSSG) ratios by geraniol and 6-gingerol. None of the three ginger ingredients affected the hyperglycemia, reduction in body weight gain, and testosterone deficiency seen in diabetic animals. Interleukin-1ÎČ and interleukin-6 levels remained unchanged. However, zingerone and geraniol ameliorated the fibrosis in diabetic prostate through suppressing the elevated prostate transforming growth factor beta 1 (TGFÎČ1) and collagen IV. Therefore, ginger ingredients could be beneficial in alleviating diabetic prostatic complications through suppressing oxidative stress and tissue fibrosis
The effect of 12C + 12C rate uncertainties on s-process yields
The slow neutron capture process in massive stars (the weak s-process)
produces most of the s-only isotopes in the mass region 60 < A < 90. The
nuclear reaction rates used in simulations of this process have a profound
effect on the final s-process yields. We generated 1D stellar models of a 25
solar mass star varying the 12C + 12C rate by a factor of 10 and calculated
full nucleosynthesis using the post-processing code PPN. Increasing or
decreasing the rate by a factor of 10 affects the convective history and
nucleosynthesis, and consequently the final yields.Comment: Conference proceedings for the Nuclear Physics in Astrophysics IV
conference, 8-12 June 2009. 4 pages, 3 figures. Accepted for publication to
the Journal of Physics: Conference Serie
THE RELATIONSHIP BETWEEN INTRUSIVE COGNITIONS AND DEFENSE MECHANISMS IN HEALTHY AND CLINICAL POPULATIONS
Purpose: to examine the relationship between defense mechanisms and intrusive cognitions in normal healthy individuals and psychiatric patients.
Methodology: The study sample consists of a healthy group (n=60; 30 males & 30 females), whereas the clinical group (n=66; 34 males, 32 females) includes patients with major depressive disorder (12 patients, 5 males, 7 females), schizophrenia (31 patients; 14 males, 17 females), obsessive-compulsive disorder (23 patients; 15 males, 8 females). We used several scales to measure the following variables: intrusive cognitions, intrusive memories, and defense mechanisms.
Finding: The results show that there is a positive correlation between defense mechanisms and intrusive cognitions in healthy and clinical groups. Intrusive cognitions were more common in the patient than in a healthy group. Furthermore, there was no significant difference between males and females in measures of intrusive thoughts and memories in both groups.
Implications: These findings have implications for behavioral treatment. Treatments used for managing posttraumatic stress disorder can also be used for the treatment of a major depressive disorder, OCD, and schizophrenia.
Originality: This investigation the relationship between intrusive cognitions and defense mechanisms in healthy and clinical populations and its implication on the cue exposure therapy that can be the treatment of intrusive cognitions and thoughts in with major depressive disorder, OCD, and schizophrenia
Evolution of Massive Stars Up to the End of Central Oxygen Burning
We present a detailed study of the evolution of massive stars of masses 15,
20, 25 and 30 \msun assuming solar-like initial chemical composition. The
stellar sequences were evolved through the advanced burning phases up to the
end of core oxygen burning. We present a careful analysis of the physical
characteristics of the stellar models. In particular, we investigate the effect
of the still unsettled reaction C(,)O on the
advanced evolution by using recent compilations of this rate. We find that this
rate has a significant impact on the evolution not only during the core helium
burning phase, but also during the late burning phases, especially the shell
carbon-burning. We have also considered the effect of different treatment of
convective instability based on the Ledoux criterion in regions of varying
molecular weight gradient during the hydrogen and helium burning phases. We
compare our results with other investigations whenever available. Finally, our
present study constitutes the basis of analyzing the nucleosynthesis processes
in massive stars. In particular we will present a detail analysis of the {\it
s}-process in a forthcoming paper.Comment: 46 pages, 15 figures. To be published in ApJ vol 611, August 10, 200
Triple-negative breast cancer: Current perspective on the evolving therapeutic landscape
Triple-negative breast cancer (TNBC) is known to have a poor prognosis and limited treatment options, namely chemotherapy. Different molecular studies have recently classified TNBC into different subtypes opening the door to potential new-targeted treatment options. In this review, we discuss the current standard of care in the treatment of TNBC in the neoadjuvant, adjuvant and metastatic settings. In addition, we summarize the ongoing phase III clinical trials evaluating different associations between the 3 pillars of anticancer treatment: chemotherapy, targeted therapy and immunotherapy
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