731 research outputs found
The physics and kinematics of the evolved, interacting planetary nebula PN G342.0-01.7
Here we aim to study the physical and kinematical characteristics of the
unstudied old planetary nebula (PN) PN G342.0-01.7, which shows evidence of
interaction with its surrounding interstellar medium. We used Integral Field
Spectra from the Wide Field Spectrograph on the ANU 2.3 m telescope to provide
spectroscopy across the whole object covering the spectral range 3400-7000
{\AA}. We formed narrow-band images to investigate the excitation structure.
The spectral analysis shows that the object is a distant Peimbert Type I PN of
low excitation, formally of excitation class of 0.5. The low electron density,
high dynamical age, and low surface brightness of the object confirm that it is
observed fairly late in its evolution. It shows clear evidence for dredge-up of
CN-processed material characteristic of its class. In addition, the low
peculiar velocity of 7 km s shows it to be a member of the young disk
component of our Galaxy. We built a self-consistent photoionisation model for
the PNe matching the observed spectrum, the H luminosity, and the
diameter. On the basis of this we derive an effective temperature and luminosity . The temperature is much
higher than might have been expected using the excitation class, proving that
this can be misleading in classifying evolved PNe. PN G342.0-01.7 is in
interaction with its surrounding interstellar medium through which the object
is moving in the south-west direction. This interaction drives a slow shock
into the outer PN ejecta. A shock model suggests that it only accounts for
about 10\% of the total luminosity, but has an important effect on the global
spectrum of the PN.Comment: 15 pages, 6 figures, A&A accepted 201
The potential gonadoprotective effects of grape seed extract against the histopathological alterations elicited in an animal model of cadmium-induced testicular toxicity
Background: Grape seed extract (GSE) is a powerful antioxidant containing high levels of bioflavonoids, vitamin C and vitamin E. The aim of the work is to study the possible protective and ameliorative effects of grape seed extract in an animal model of cadmium (Cd)-induced testicular toxicity in rats.Materials and methods: A thirty-day oral gavage study in adult male albino rats was performed using 32 animals, randomly divided into four equal groups; negative control, Cd (5 mg/k/day), GSE (100 mg/k/day), and Cd + GSE. Testicular weights were measured. Haematoxylin and eosin (H&E) staining and proliferating nuclear cell antigen (PCNA) immunohistochemistry, as a marker for proliferation were done. Morphometric parameters were assessed and subjected to statistical analysis.Results: The H&E results showed atrophy and distortion of the seminiferous tubules (STs) with sloughing of the spermatogenic epithelium in cadmium group. The interstitial spaces were widened and showed oedema and mononuclear cell infiltrations. No remarkable changes were observed in the GSE-only group when compared to the control group. In Cd + GSE group, maintaining of the STs and their lining cells was evident. The immunohistochemical results showed marked positive PCNA immunoreactivity in both control and GSE groups, while negative immunoreaction was noticed in Cd group. Limited positive PCNA immunoreactivity was ameliorated in Cd + GSE group.Conclusions: Grape seed extract protected against cadmium-induced testicular toxicity in rats, reducing induced histopathological changes, and maintaining testicular histoarchitecture
Geological and groundwater potential studies of El Ismailiya master plan study area
There are no author-identified significant results in this report
Diabetes, coronary artery disease and erectile dysfunction doppler study
ObjectivesTo assess the role of measuring cavernosal artery blood flow as a screening tool for ischemic heart disease in patients with erectile dysfunction (ED).MethodsA total of 303 male patients with ED were enrolled in this study. Patients were interviewed for ED using the International Index of Erectile Function. The penile vasculature was assessed using color Doppler ultrasonography and the Digital Inflection Rigidometer. All patients were referred to a cardiologist for evaluation of ischemic heart disease (IHD). All patients underwent routine laboratory investigations, plus total testosterone and prolactin assessments.ResultsSeventy-six percent of the patients had organic causes of ED. Of the 303 patients, 31.4% had different degrees of IHD. A statistically significant association was found between the presence of IHD and arteriogenic causes of ED, a poor response to intracorporal injection, poor rigidity in the Digital Inflection Rigidometer, and low peak systolic velocity (PSV) in the cavernosal arteries (P<0.05 for each). No statistically significant association was found between the presence of IHD and increasing end-diastolic velocity values or decreasing resistive index in the cavernosal arteries (P<0.05 for each). A statistically significant association was found between a higher grade of IHD and a decreasing PSV value (P<0.05).ConclusionsThe results of this study established that a reduced PSV of the cavernous artery is associated with IHD. Determining the PSV could be a reliable screening tool for the detection of IHD in patients with ED
Galaxy emission line classification using 3D line ratio diagrams
Two-dimensional (2D) line ratio diagnostic diagrams have become a key tool in
understanding the excitation mechanisms of galaxies. The curves used to
separate the different regions - HII-like or else excited by an active galactic
nucleus (AGN) - have been refined over time but the core technique has not
evolved significantly. However, the classification of galaxies based on their
emission line ratios really is a multi-dimensional problem. Here we exploit
recent software developments to explore the potential of three-dimensional (3D)
line ratio diagnostic diagrams. We introduce a specific set of 3D diagrams, the
ZQE diagrams, which separate the oxygen abundance and the ionisation parameter
of HII region-like spectra, and which also enable us to probe the excitation
mechanism of the gas. By examining these new 3D spaces interactively, we define
a new set of 2D diagnostics, the ZE diagnostics, which can provide the
metallicity of objects excited by hot young stars, and which cleanly separate
HII region-like objects from the different classes of AGNs. We show that these
ZE diagnostics are consistent with the key log[NII]/H vs.
log[OIII]/H diagnostic currently used by the community. They also have
the advantage of attaching a probability that a given object belongs to one
class or to the other. Finally, we discuss briefly why ZQE diagrams can provide
a new way to differentiate and study the different classes of AGNs in
anticipation of a dedicated follow-up study.Comment: 21 pages, 15 figures, accepted for publication in ApJ. Due to size
limitations, the supplementary STL file for the 3D-printable diagram is
available here: http://www.mso.anu.edu.au/~fvogt/online_material.htm
Call Blocking Probabilities Reduction of Channel Assignment in Mobile Communication Systems
In wireless mobile communication systems, the radio spectrum is limited resource. However, efficient use of such limited spectrum becomes more important when the two, three or more cells in the network become hot - spot. The use of available channels has been shown to improve the system capacity. The role of channel assignment scheme is to allocate channels to cells in such way as to minimize call-blocking probability or call dropping probability and also maximize the quality of service. Different channel allocation schemes are in use for mobile communication systems, of which the Hybrid channel allocation (HCA) a combination of Fixed and Dynamic channel allocation schemes (FCA and DCA respectively) was effective. In this paper, the performance of three different channel allocation schemes FCA, DCA and HCA will be analytically compared and the results are presented
Stem cells and metformin synergistically promote healing in experimentally induced cutaneous wound injury in diabetic rats
Introduction. Diabetes mellitus (DM) is a serious, chronic metabolic disorder commonly complicated by diabetic foot ulcers with delayed healing. Metformin was found to have a wound healing effect through several mechanisms. The current study investigated the effect of both bone marrow-derived mesenchymal stem cells (BM-MSCs) and metformin, considered alone or combined, on the healing of an experimentally induced cutaneous wound injury in streptozotocin-induced diabetic rats.Material and methods. Forty adult male albino rats were used. Diabetes was induced by single intravenous (IV) injection of streptozotocin (STZ). Next, two circular full thickness skin wounds were created on the back of the animals, then randomly assigned into 4 groups, ten rats each. BM-MSCs were isolated from albino rats, 8 weeks of age and labeled by PKH26 before intradermal injection into rats of Group III and IV. Groups I (diabetic positive control), II (metformin-treated, 250 mg/kg/d), III (treated with 2×106 BM-MSCs), and IV (wounded rats treated both with metformin and BM-MSCs cells). Healing was assessed 3, 7, 14, and 21 days post wound induction through frequent measuring of wound diameters. Skin biopsies were obtained at the end of the experiment.Results. Gross evaluation of the physical healing of the wounds was done. Skin biopsies from the wound areas were processed for hematoxylin and eosin (H&E), Masson’s trichrome staining and immunohistochemical staining for CD31. The results showed better wound healing in the combined therapy group (IV) as compared to monotherapy groups.Conclusions. Although both metformin and BM-MSCs were effective in the healing of experimentally induced skin wounds in diabetic rats, the combination of both agents appears to be a better synergistic option for the treatment of diabetic wound injuries
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