A Search for Supernova-Remnant Masers Toward Unidentified EGRET Sources

Supernova remnants expanding into adjacent molecular clouds are believed to be sites of cosmic ray acceleration and sources of energetic gamma-rays. Under certain environmental conditions, such interactions also give rise to unusual OH masers in which the 1720 MHz satellite line dominates over the more common 1665/7 MHz emission. Motivated by the apparent coincidence of a handful of EGRET sources with OH(1720 MHz) maser-producing supernova remnants, we have carried out a search using the Very Large Array for new OH(1720 MHz) masers within the error regions of 11 unidentified EGRET sources at low Galactic latitude. While a previously known maser associated with an HII region was serendipitously detected, initial results indicate that no new masers were found down to a limiting flux of, typically, 50 mJy. We discuss the implications of this result on the nature of the unidentified Galactic EGRET sources.Comment: 5 pages, 1 figure. To appear in Proceedings, GAMMA2001 (Baltimore, MD, April 4-6, 2001), eds. N. Gehrels, C. Shrader, and S. Rit

Synthesis and characterization of a novel amphoteric terpolymer nanocomposite for enhanced oil recovery applications

Water-soluble polymers are highly applied to increase the recovery from oil reservoirs. The application of these polymers in enhanced oil recovery (EOR) has some limitations regarding chemical, thermal and mechanical degradation at harsh reservoir condition. In this research, a novel stable terpolymer has been synthesised by preparing and grafting vinylbenzyl starch with poly (acrylamide/ acrylic acid/ acrylacyloxyethyltrimethyl ammonium chloride) in the presence of silica nanoparticles via free radical emulsion polymerization. Different stability investigations have been applied for the synthesised polymer including temperature, salinity and shear stability analyses at harsh conditions. The chemical structure of the novel polymer has been characterized using numerous methods including proton nuclear magnetic resonance (1H NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and high-resolution transmission electron microscope (TEM). Thermal properties have been evaluated by thermal gravimetric analysis (TGA). The rheological properties have been studied at harsh reservoir conditions in terms of formation water salinity, temperature, and shear rate. The results have shown that the introduction of vinylbenzyl starch has significantly enhanced the thermal and chemical stability of the prepared polymer. Moreover, flooding experiments conducted on sandstone core have shown that the synthesised terpolymer can enhance the oil recovery up to 43% at polymer concentration of 3 g/L

Correlation between CRP and early failure of arteriovenous fistula (AVF)

Background: Arteriovenous Fistula (AVF) is the ideal method of vascular access for patients on maintenance hemodialysis (HD). Therefore it is an important part of treatment in HD. There are several observations that indicate the role of inflammation in failure of AVF. The aim of this study was to evaluate the hematologic and inflammatory biomarkers in early AVF failure. Methods: This case-control study included 110 ESRD patients, whom were undergone AVF creation, divided in two groups. About 700 radius-cephalic AVF were created during these two years. We found 55 cases with AVF failure. In this study, we compared those 55 failures with 55 functional AVF which were selected using randomized sampling from the rest of patients according to age, gender, and AVF location. Levels of serum C-reactive protein (CRP) were checked in both groups to evaluate the relation between AVF failure and CRP level before surgery. Results: The mean±SD age of the patients was 49.7±17.28 years. CRP was positive in 34 patients (61.8) with unsuccessful fistula function, while only 4 (7.3) of those with successful AVF had positive CRP and the rest had negative CRP. The difference between the two groups of patients was strongly significant (p<0.001). Statistically, there was not any significant difference between the average of age (p: 0.580) of patients in the control and experimental groups. However, the gender (p: 0.832) discrepancies was not meaningful between the groups. Conclusion: AVF thrombosis is one of the main complications after AVF creation. Therefore, it is recommended to check CRP before AVF surgery to prevent possible failure of the fistula function

Antiviral activity of Aloe vera against herpes simplex virus type 2: An in vitro study

In this study we tested the antiviral activity of a crude hot glycerine extract of Aloe vera gel which was grown in Bushehr (Southwest of Iran) against HSV-2 replication in Vero cell line. The extract showedantiviral activity against HSV-2 not only before attachment and entry of virus to the Vero cells but also on post attachment stages of virus replication. The IC50 before attachment and entry of virus to the cellsis 428 ìg/ml and the CC50 value which is the cytotoxicity of the extract for Vero cells is 3238 ìg/ml, while the calculated selectivity index (SI) is 7.56. Also, IC50 of extract on post attachment stages of replicationis 536 ìg/ml and the SI value for inhibition of the post attachment stages of HSV-2 replication is 6.04. Therefore, compounds of Aloe vera from Bushehr could be a good candidate as a natural source for antiviral drug development against HSV-2

Relationship between Vessel Diameter and Time to Maturation of Arteriovenous Fistula for Hemodialysis Access

Introduction. Native arteriovenous fistula (AVF) is the recommended vascular access for HD patients by the Dialysis Outcomes Quality Initiative (DOQI) guidelines. The aim of our study was to determine the correlation between diameter and maturation of vessels in radiocephalic AVF. Methods. A prospective cross-sectional study carried out during 2006-2007 on 96 hemodialysis patients from Hasheminejad Kidney Center with non probability selection, all of them with end to side native AVF. Results. In this population 62.5% had wrist (distal radial artery) AVF and 37.5% had antecubital (proximal radial artery) AVF. The mean diameter of artery was 2.57 mm (SD = 1.09) and the mean diameter of vein was 2.40 mm (SD = 0.79). The mean of maturation period was 38.60 days (SD = 42.13). There were no relationship between duration of maturation period and diabetes mellitus, sex, age, diameter of vein and artery (P > 0.05). Period of maturation showed some correlation with the diameter of vein (P = 0.04) in patients with distal radiocephalic fistulae. Conclusions. The maturation of fistula shows correlation with vein diameter, but no correlation was seen with diameter of the arteries. There is much discrepancy between times to maturation in various reports. The average time for fistula maturation was 38/6 days in our study

HST Paschen alpha and 1.9 micron imaging of Sgr A West

We present HST/NICMOS images at 0.2" resolution of the HI Paschen Alpha (PaA) emission line in a 70" x 90" region of the Galactic center centered on the non-thermal radio source Sgr A*. The majority of the emission arises from ionized gas in the mini-spiral in the central parsec. PaA emission is also seen from 26 stellar sources, presumably early-type stars with mass-loss winds. The new data reveal significant small-scale structure (<1"~0.04pc) in the ionized gas of the mini-spiral; low surface brightness emission features are also seen for the first time. Extinction, estimated from the ratio of observed PaA emission to 6-cm continuum emission, varies from 20 to 50 mag with a median Av=31.1 mag, in excellent agreement with earlier estimates for the stellar sources and indepedent measurements derived using H92alpha recombination line data. Large increases in extinction are seen along the periphery of the ionized gas, suggesting that the ionized gas is partially extincted by dust in the molecular clouds at the outside of the ionized regions. The small-scale, filamentary structures in the ionized gas have a free thermal expansion time of only ~ 3000 yrs; either magnetic fields or mass-loss winds from the hot emission line stars may contain the ionized filaments. For both the ionized gas and the stellar continuum, the centroids of the emission remain within ~+/- 1" from a radius of 2" out to 40", providing further evidence that Sgr A* is indeed at or extremely close to the dynamical center of the Galactic nucleus stellar distribution. The 1.9 micron surface brightness increases inwards to 0.9" and then decreases or levels off closer to Sgr A*, possibly indicating the core radius of the central stellar distribution or depletion of the late-type stars by stellar collisions near the central black hole.Comment: 43 pages, 15 figures, 2 tables; Accepted to ApJ (9/1/03 issue

Effect of gait retraining on balance, activities of daily living, quality of life and depression in stroke patients

Objectives: Stroke is one of the most common neurological diseases and it is the main cause of physical and mental disability and staying in house. Gait difficulties have high incidence in patients with stroke. So the aim of this study was to investigate the effect of gait retraining on balance, activities of daily living, quality of life and depression in stroke patients Methods: This study was a clinical trial without control group. Sampling was performed by convenience sampling method and 18 patients participated. After recording demographic data, Berg Balance Scale, Barthel Index, SF36 questionnaire and Beck Depression Inventory-II used in pre-test and post-test to assess balance, activities of daily living, quality of life and depression, respectively. Data were analyzed using Pearson correlation coefficient and paired T-test. Results: The results showed statistically significant correlation in pre-test and difference between mean score of the all instruments before and after the intervention. Discussion: According to high prevalence of gait difficulties in stroke patients, it seems interventions in this area were necessary. Statistical results showed that the gait retraining intervention may have a positive effect on improving balance, activities of daily living, quality of life and depression of these patients. According to lack of information in this area, further research is needed

H2 and NO2 gas sensors with ZnO nanobelt layer on 36° LiTaO3 and 64° LiNbO3 SAW transducers

Single crystal nanobelts of ZnO were synthesized and deposited onto 36° YX LiTaO&lt;sub&gt;3&lt;/sub&gt; and 64° YX LiNbO&lt;sub&gt;3&lt;/sub&gt; surface acoustic wave (SAW) devices for gas sensing applications. Sensor response, defined as the change in resonant frequency, was measured for H&lt;sub&gt;2&lt;/sub&gt; and NO&lt;sub&gt;2&lt;/sub&gt; between 20 and 200°C. Measured sensor responses were 3.5 kHz towards 10 ppm NO&lt;sub&gt;2&lt;/sub&gt; for a 64° LiNbO&lt;sub&gt;3&lt;/sub&gt; SAW transducer operating at 160°C and 3 kHz towards 1% H&lt;sub&gt;2&lt;/sub&gt; for a 36° LiTaO&lt;sub&gt;3&lt;/sub&gt; SAW transducer operating at 185°C temperature