Unbound states in quantum heterostructures

We report in this review on the electronic continuum states of semiconductor Quantum Wells and Quantum Dots and highlight the decisive part played by the virtual bound states in the optical properties of these structures. The two particles continuum states of Quantum Dots control the decoherence of the excited electron – hole states. The part played by Auger scattering in Quantum Dots is also discussed

Stress Hyperglycaemia in Hospitalised Patients and Their 3-Year Risk of Diabetes: A Scottish Retrospective Cohort Study

Background<p></p> Hyperglycaemia during hospital admission is common in patients who are not known to have diabetes and is associated with adverse outcomes. The risk of subsequently developing type 2 diabetes, however, is not known.<p></p> We linked a national database of hospital admissions with a national register of diabetes to describe the association between admission glucose and the risk of subsequently developing type 2 diabetes.<p></p> Methods and Findings<p></p> In a retrospective cohort study, patients aged 30 years or older with an emergency admission to hospital between 2004 and 2008 were included. Prevalent and incident diabetes were identified through the Scottish Care Information (SCI)-Diabetes Collaboration national registry. Patients diagnosed prior to or up to 30 days after hospitalisation were defined as prevalent diabetes and were excluded.<p></p> The predicted risk of developing incident type 2 diabetes during the 3 years following hospital discharge by admission glucose, age, and sex was obtained from logistic regression models. We performed separate analyses for patients aged 40 and older, and patients aged 30 to 39 years.<p></p> Glucose was measured in 86,634 (71.0%) patients aged 40 and older on admission to hospital. The 3-year risk of developing type 2 diabetes was 2.3% (1,952/86,512) overall, was <1% for a glucose ≤5 mmol/l, and increased to approximately 15% at 15 mmol/l. The risks at 7 mmol/l and 11.1 mmol/l were 2.6% (95% CI 2.5–2.7) and 9.9% (95% CI 9.2–10.6), respectively, with one in four (21,828/86,512) and one in 40 (1,798/86,512) patients having glucose levels above each of these cut-points. For patients aged 30–39, the risks at 7 mmol/l and 11.1 mmol/l were 1.0% (95% CI 0.8–1.3) and 7.8% (95% CI 5.7–10.7), respectively, with one in eight (1,588/11,875) and one in 100 (120/11,875) having glucose levels above each of these cut-points.<p></p> The risk of diabetes was also associated with age, sex, and socio-economic deprivation, but not with specialty (medical versus surgical), raised white cell count, or co-morbidity. Similar results were obtained for pre-specified sub-groups admitted with myocardial infarction, chronic obstructive pulmonary disease, and stroke.<p></p> There were 25,193 deaths (85.8 per 1,000 person-years) over 297,122 person-years, of which 2,406 (8.1 per 1,000 person-years) were attributed to vascular disease. Patients with glucose levels of 11.1 to 15 mmol/l and >15 mmol/l had higher mortality than patients with a glucose of <6.1 mmol/l (hazard ratio 1.54; 95% CI 1.42–1.68 and 2.50; 95% CI 2.14–2.95, respectively) in models adjusting for age and sex.<p></p> Limitations of our study include that we did not have data on ethnicity or body mass index, which may have improved prediction and the results have not been validated in non-white populations or populations outside of Scotland.<p></p> Conclusion<p></p> Plasma glucose measured during an emergency hospital admission predicts subsequent risk of developing type 2 diabetes. Mortality was also 1.5-fold higher in patients with elevated glucose levels. Our findings can be used to inform patients of their long-term risk of type 2 diabetes, and to target lifestyle advice to those patients at highest risk

The Ni-deposited carbon felt as substrate for preparation of Pt-modified electrocatalysts: Application for alkaline water electrolysis

A Ni-modified carbon felt (C) electrode (C/Ni) was used as a substrate for preparation of Pt-modified electrode in view of its possible application as electrocatalytic material for the hydrogen evolution activity. The prepared electrode was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV) techniques. The hydrogen evolution activity of the electrode was assessed by cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the modification of Ni-deposited C by loading low amount of Pt could enhance the hydrogen evolution activity of the electrode. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.BAP-52-59-2011 Firat University Scientific Research Projects Management UnitThis study has been financially supported by the Bingöl University Scientific Research Projects (BÜBAP) Coordination Unit (Project Number: BAP-52-59-2011 ). The authors are greatly thankful to BÜBAP. The authors are also greatly thankful to Prof. Mustafa Çulha (Yeditepe University) for SEM analysis

Elimination of copper in tissues and organs of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) following dietary exposure

Copper (Cu) elimination was investigated in the tissue and organs of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792), after Cu-free diets exposure. In the current study, fish were fed to satiation on diets containing 0.022 (Group 1; Control), 0.043 (Group 2), 0.123 (Group 3), 0.424 (Group 4) g Cu*kg-1 diet for 60 days before elimination experiment. A total of 288 fish (mean weight 84.28±1.05 g) were randomly transferred to 12 fibreglass tanks. The fish were fed the Cu-free diet twice daily, until apparent satiation, during 60 days. Subsequently, the experiment was established for a period of elimination, during which samples were taken at days 15, 30, 45 and 60. Cu concentration in the muscle, gill tissue, digestive system, liver and whole body of fish were determined after 60 days depuration. Cu concentrations in tissues of rainbow trout decreased during depuration period, and the order of Cu elimination in tissue and organs of rainbow trout was: digestive system (73.1 %), then gill (41.1 %), muscle (31.5 %) and liver (17.2 %) for group 2; digestive system (74.1%), then muscle (65.8%), gill (60.0%) and liver (34.6%) for group 3; and digestive system (85.8%), then muscle (80.8%), liver (50.5%) and less/equal in gill (50.2%) for group 4. In statistical analysis, both groups and time were significant factors (P<0.05) on elimination rate. Moreover, significant interaction between groups and time were identified on elimination rate. Digestive system showed the fastest elimination rates of Cu at all groups compared with other tissues. © A. Gündogdu et al

Assessment of image quality of a standard and three dose-reducing protocols in adult cranial CT

The purpose of this study was to analyze the effect of various tube current settings (mAs) and optimize the image quality and dose for adult cranial CT protocol. Sixty adult patients who underwent a cranial CT scanning for different indications were subdivided into three subgroups. Subjective image and noise quality scores and quantitative noise measurements were selectively studied on three reference levels (cerebellar, basal ganglia and centrum semiovale levels). For each subgroup, only one level was studied. Head circumference (HC) and the maximum anteroposterior diameter (MAPD) of each patient were measured. At 50% decreased dose protocol, there was no poor quality score at any level. At nearly 60% decreased dose protocol, the incidence of poor quality scores was much higher at the cerebellar level than at the other two levels. For the same protocol number, quantitative noise measurements were higher at the cerebellar level than the other two supratentorial levels. The correlation was found to be significant between HC, MAPD and quantitative noise measurements, and there was a non-significant correlation between HC and subjective noise scores. In adult cranial CT, depending on the level, a dose reduction of up to 60% may be possible while maintaining image quality. © Springer-Verlag 2004

Venous reflux: Measurement variability due to positional differences [Venöz reflü: hasta pozisyonuna bagli ölçüm farkliliklari.]

PURPOSE: The purpose of this study was to evaluate the role of the subject's position and two different maneuvers in the reflux measurements in femoral veins. MATERIALS AND METHODS: Venous reflux times in the common femoral vein (CFV) and superficial femoral vein (SFV) were studied in 50 healthy subjects (25 women, 25 male) aged between 22-57 years-old while the subjects were in supine and standing positions. Reflux was provocated only by Valsalva maneuver (VM) when the subject was lying down, whereas it was provocated by (1) Valsalva maneuver and (2) compression and release maneuver, respectively, when the subject was standing. Reflux times were recorded with each of the three methods. RESULTS: Regarding CFV, a reflux time of 1 second or more was recorded in 29 limbs (29%) only in the supine position. Of these 29 measurements, 19 were between 1 and 1.9 sec and 8 between 2 and 2.9 sec. When the subjects were examined in the standing position, the prevalence of reflux lasting more than 1 sec substantially decreased (5%). The prevalence of reflux lasting less than 0.5 sec was 97% with standing compression maneuver, 84% with standing VM and 27% with supine VM. Similarly, prevalence of reflux of longer than 0.5 sec or 1 sec was lower in the standing position than in the supine position in SFV. In CFV, mean reflux time was 1.3 sec in the supine position, whereas it was 0.7 sec and 0.4 sec with standing compression and standing Valsalva maneuvers, respectively. Corresponding values in SFV were 0.5 sec, 0.3 sec and 0.2 sec, respectively. CONCLUSION: The probability of making a false positive diagnosis of pathological reflux is high with supine examinations. When an examination in the supine position reveals a reflux time of longer than 1 second, making the patient stand up is expected to yield more reliable results. Compression and release maneuver, with its lowest false positive reflux prevalence, is the most reliable method in the evaluation of venous insufficiency

Migration of an Intrauterine Contraceptive Device to the Ovary

We present the case of a 37-year-old woman with a history of 2 consecutive insertions of intrauterine contraceptive devices (IUDs) 3 years before she was referred to us for sonographic evaluation of lower abdominal pain. The first of the IUDs was presumed to have been expulsed spontaneously, and 3 months after insertion of the second device, the patient had begun experiencing lower abdominal pain. Medical treatment with antibiotics and spasmolytics had been unsuccessful. We performed transvaginal sonography, which revealed the presence of an IUD in the uterus and a 2-cm linear metallic echogenic area in the left ovary, believed to represent another IUD. Anteroposterior radiography confirmed that there were 2 IUDs in the pelvis, and CT demonstrated 1 IUD in the uterus and another in the left ovary. The patient underwent laparoscopic removal of the ovarian IUD and was discharged in good condition. To our knowledge, this is the first report of migration of an IUD to the ovary detected on transvaginal sonography. We recommend consideration of this possibility during evaluation of women with unexplained chronic pelvic pain. © 2004 Wiley Periodicals, Inc

Double inversion recovery sequence in temporal lobe epilepsy: preliminary results [Temporal lob epilepsisinde "double inversion recovery" sekansi: ön sonuçlar.]

PURPOSE: DIR (double inversion recovery) is a sequence with the hybrid contrast of both FLAIR and STIR sequences, produced by the application of double inversion recovery pulse. It has been suggested that DIR provides high sensitivity to lesions with low T2 contrast. The purpose of this study was to test the hypothesis that DIR sequence is superior to conventional sequences in the identification of mesial temporal sclerosis and other temporal lobe lesions in patients with temporal lobe epilepsy. MATERIALS AND METHODS: Thirty-three subjects with a prediagnosis of temporal lobe epilepsy and ten healthy control subjects with no abnormality on magnetic resonance imaging studies have been studied with DIR, FLAIR and T2W sequences. Coronal images through temporal lobes and hippocampus were acquired. Qualitatively, overall sensitivity to the presence of lesions, hippocampal lesion detectability, temporal horn dilatation and artifacts were evaluated in temporal lobe epilepsy cases and quantitatively, hippocampal and white matter signal-to-noise ratio as well as hippocampus-white matter contrast-to-noise ratio were calculated in the healthy subjects. Subjective scores were graded on a scale of 3 or 4 points. RESULTS: Signal-to-noise ratio scores were higher on T2W sequence, however contrast-to-noise ratio scores were higher on DIR sequence compared to the other two sequences. Imaging findings were compatible with mesial temporal sclerosis in seven patients, tumoral mass in two, and chronic infarct in four. DIR sequence was less sensitive to hippocampal atrophy than the other two sequences because of cerebrospinal fluid artifacts. Overall sensitivity to the presence of lesions and hippocampal lesion detectability scores, although similar among three sequences, were highest with DIR sequence. However, lesion sensitivity scores were highest for lesions compatible with mesial temporal sclerosis and for solid masses and lowest for cystic lesions on DIR sequence. CONCLUSION: Despite the presence of artifacts, DIR is a sequence providing high sensitivity to mesial temporal sclerosis like lesions at hippocampus. DIR might be useful as an additional sequence when the other conventional sequences reveal a suspicious lesion with no accompanying hippocampal atrophy