Results 1 - 10 of 11093
Results 1 - 10 of 11093. Search took: 0.028 seconds
|Sort by: date | relevance|
[en] It is generally thought that deposition of device-quality oxide semiconductors requires somewhat high oxygen supply in order to reduce oxygen deficiency and to suppress generation of free electrons. This paper reports that such high oxygen supply is not an essential requirement for a representative amorphous oxide semiconductor, amorphous In-Ga-Zn-O (a-IGZO). That is, the optimum oxygen flow rate ratio (R) is 3% for standard (STD) sputtering with the base pressure of 10 Pa, while it is reduced dramatically to 10-10% for ultrahigh vacuum (UHV) sputtering with the base pressure of 10 Pa. We consider that the ultralow optimum oxygen supply originates from residual hydrogen, because the STD and the UHV films have different hydrogen contents at the orders of 10 and 10 cm, respectively. This comparison also suggests that the inclusion of impurity hydrogen widens the optical bandgap by 0.1 eV, which causes a bandgap minimum by post annealing at 500°C for the STD a-IGZO films accompanying the removal of incorporated hydrogen as HO. Furthermore, crystallization onset temperature is reduced remarkably by 100 K for the UHV a-IGZO films. (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] Wurtzite (WZ) and hexagonal boron nitride (h-BN) are closely related crystal structures, both of which belong to the hexagonal crystal family. However, the WZ structure is commonly found in binary compounds such as ZnO and CdS, whereas crystals having a h-BN structure are very rare. In this study, a WZh-BN structural transition is predicted to take place at high temperatures using molecular dynamic simulations with a generic pair potential model. This transition is entropically driven, whereby cations in crystal show extremely high mobility and are able to jump between nearby lattice sites when the temperature is higher than the critical point. Density function theory calculations for 14 AB compounds show that ZnO is the best candidate material that will undergo the WZh-BN transition at high temperatures. This study predicts a new ferroelectric-paraelectric phase transition in WZ crystals that will change the materials' physical properties such as piezoelectricity and pyroelectricity. (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] In this article, suitable imaging of stress reactions and stress fractures in athletes will be examined. Diagnostic procedures include X-ray, computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy. MRI represents the gold standard for these types of injuries. Of all imaging techniques, MRI shows the highest sensitivity in terms of diagnostic and prognostic aspects in stress reactions and stress fractures. Early performance of MRI to evaluate the staging, therapy and prognosis of the healing process is recommended. (orig.)
[de]In diesem Beitrag wird die geeignete Diagnostik von Stressreaktionen und Stressfrakturen beim Sportler dargestellt. Für die Diagnosestellung kommen Röntgenaufnahmen, Computertomographie (CT), Magnetresonanztomographie (MRT) sowie die Skelettszintigraphie zum Einsatz. Die MRT stellt bei diesen Verletzungen den Goldstandard dar. Die MRT weist von allen radiologischen Verfahren im Hinblick auf Diagnostik und Prognostik von Stressreaktionen und Stressfrakturen die höchste Sensitivität auf. Die frühzeitige Durchführung einer MRT zur Diagnostik, Gradeinteilung, Therapieplanung und Heilungsprognose von Stressreaktionen ist sinnvoll. (orig.)
[en] Silica nanoparticles (SNPs) are known as intrinsic radiolabeling agents and offer a fast and reliable approach to deliver theranostic agents into targeted organs. Radiolabeled amorphous silica nanoparticles are of great interest to radiation oncology communities. In order to improve the performance of these nano materials in cancer diagnosis and treatment, their inherent properties, such as surface area and the ability to accumulate in cancer cells, should be enhanced. Pyridine functionalized mesoporous silica MCM-41 is known as a potential anticancer-drug delivery system with high suface area. In thiswork, in order to produce an image-guided drug delivery system for diagnostic applications, Ga radionuclide was grafted on pyridine functionalized MCM-41. The nanoparticles were assessed with atomic force microscopy (AFM), paper chromatography, X-ray diffraction, FTIR spectroscopy, CHN and TGA/DTA analyses. The pharmacokinetic profile evaluation of the radiolabeled nano silica, Ga-Py-Butyl@MCM-41, was done in Fibrosarcoma tumor-bearing mice. This labeled nanocomposite with appropriate blood circulation in body, high structural stability, high tumor/blood ID/g% ratio and fast excretion from the body can be proposed as an efficient nano engineered composite for upcoming tumor targeting/imaging nanotechnology-based applications.
[en] In this study, UCl was prepared by the reaction of HCl gas with UO in the LiCl-KCl eutectic. Then, the electrochemical behavior of U and U on a Mo cathode was investigated by various electrochemical techniques. The reduction process of U was regarded as two steps: U+e=U; U+3e=U. Diffusion coefficients of U and U, the apparent standard potential of U/U, U/U as well as U/U in the LiCl-KCl molten salt on the Mo electrode was determined by numerous electrochemical methods. The thermodynamic functions of formation of Gibbs free energy of UCl and UCl are calculated as well.
[en] The transient radiation-induced attenuation (RIA) of two different versions of pure-silica-core (PSC) multimode optical fibers (so-called solarization-resistant fibers) exposed to nanosecond 1 MeV X-ray pulses are investigated. On-line RIA spectra measurements at both room temperature (RT) and liquid nitrogen temperatures (LNT) in the range 1-3.5 eV are performed. Following the RIA kinetics, the properties of the metastable defects that are bleached just after the pulse are discussed. The spectral decomposition of the RIA is performed using known Gaussian bands associated to point defects absorbing in this spectral range. For both fiber types, the generation and the post-irradiation kinetics of the self-trapped holes (STHs) that are the main contributor to the transient RIA are investigated particularly. Moreover, thanks to the measurements performed at low temperatures the complex temperature dependence of the kinetics of self-trapped holes and some chlorine-related species is characterized. (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] To compare relative and absolute dose-volume parameters (DV) of the rectum and their clinical correlation with acute and late radiation proctitis (RP) after radiotherapy (RT) for prostate cancer (PCa). 366 patients received RT for PCa. In total, 49.2% received definitive RT, 20.2% received postoperative RT and 30.6% received salvage RT for biochemical recurrence. In 77.9% of patients, RT was delivered to the prostate or prostate bed, and additional whole pelvic RT was performed in 22.1%. 33.9% received 3D-RT, and 66.1% received IMRT. The median follow-up was 59.5 months (18.0-84.0 months). The relative (in %) and absolute (in ccm) rectal doses from 20-75 Gy including the receiver operating characteristics curves (rAUC) from 30-65 Gy (in % and ccm) and several other clinical parameters were analyzed in univariate and multivariate analyses. We performed the statistical analyses separately for the entire cohort (n = 366), patients with (n = 81) and without (n = 285) pelvic RT, comparing RP vs. RP grade I. With the exception of the V50 (p = 0.02) in the univariate analyses for acute RP in the entire patient cohort, no absolute DV parameter (in ccm) was statistically significant associated with either acute or late RP. In the multivariate analyses, 3D-RT (p 0.008) and rAUC (p = 0.006) were significant parameters for acute RP for the entire cohort, and the V50 (p = 0.01) was the significant parameter for patients with pelvic RT. The rAUC (p = 0.004) was significant for RT to the prostate/prostate bed. Regarding the statistical analysis for late RP, the rAUC (p = 0.001) was significant for the entire cohort, and rAUC (p = 0.001) was significant for RT of the prostate/prostate bed. No parameter was significant in patients with pelvic RT. Absolute DV parameters in ccm are not required for RT in PCa patients. (orig.)
[de]Vergleich von absoluter und relativer Dosisvolumenbelastung des Rektums und Korrelation mit akuter und später radiogener Proktitis (RP) nach Radiotherapie (RT) beim Prostatakarzinom (PCa) 366 PCa-Patienten erhielten eine RT: 49,2 % eine definitive, 20,2 % eine postoperative und 30,9 % eine Salvage-RT. Bei 78,3 % wurde Prostata oder Prostatabett bestrahlt und bei 21,7 % zusätzlich der Beckenlymphabfluss. Die Dosen betrugen 60 Gy bei postoperativer, 66 Gy bei Salvage- und 74-78 Gy bei definitiver RT. Eine 3D-RT erhielten 33,9 %, eine IMRT 66,1 %. Das mediane Follow-up betrug 59.5 Monate (18.0-84.0 Monate). Die relativen (%) und absoluten (ccm) rektalen Dosisvolumina (DV) von 20-75 Gy, sowie die Fläche unter der Kurve (rAUC) von 30-65 Gy (in % und ccm) und weitere klinische Parameter wurden univariat und multivariat untersucht. Die statistische Auswertung hinsichtlich keine RP vs. RP Grad I wurde für das gesamte Kollektiv (n = 366), für Patienten mit (n = 81) und ohne (n = 285) pelvine RT durchgeführt. Mit Ausnahme der V50 (p = 0,02) in der univariaten Analyse für die akute RP im Gesamtkollektiv war kein absoluter DV-Parameter in ccm signifikant mit akuter oder später RP assoziiert. In der multivariaten Analyse waren die 3-D-RT (p 0,008) und die rAUC (p = 0,006) im Gesamtkollektiv und die V50 (p = 0,01) bei pelviner RT signifikant mit einer akuten RP assoziiert. Die rAUC (p = 0,004) war bei der Bestrahlung beschränkt auf Prostata/Prostatabett multivariat signifikant. Hinsichtlich der späten RP war die rAUC (p = 0,001) für das Gesamtkollektiv und die rAUC (p = 0.001) für die Bestrahlung von Prostata/Prostatabett signifikant. Kein Parameter war multivariat signifikant für die späte RP bei additiver Beckenbestrahlung. Absolute DV-Parameter in ccm zusätzlich zu relativen DV "constraints" des Rektums werden für die RT beim PCa nicht benötigt. (orig.)
[en] To explore the utility of dynamic contrast-enhanced (DCE) MR imaging for quantitative analysis of blood-brain barrier disruption in mild traumatic brain injury (mTBI) patients with post-concussion syndrome (PCS). Forty-four consecutive patients with PCS after mTBI and 32 controls were included in this retrospective study. K and v from DCE MR imaging were analyzed at contrast-enhancing lesions, T2 hyperintense white matter (WM) lesions, normal-appearing white matter (NAWM), and predilection sites for diffuse axonal injury (Location). The Mann-Whitney U-test was performed to compare the parameters between mTBI patients and controls and the parameters were correlated with neuropsychological tests using Mann-Whitney U-test and Spearman rank correlation. The median v of the T2 hyperintense WM lesions in mTBI patients (n=21) was higher than that of NAWM in controls (p=.027). Both median K and v at NAWM were also significantly higher in mTBI patients than in controls (p=.023 and p=.029, respectively). In addition, mTBI patients had higher K and v at Location than controls (p=.008 and p=.015, respectively). VLT (delayed recall) scores were significantly correlated with v values at T2 hyperintense WM lesions (p=-0.767, p=.044). The median v at Location was significantly higher in patients with atypical performance in the digit span test (forward) than in those with average or good performance (p=.043). mTBI patients with PCS had higher K and v values than controls not only at T2 hyperintense WM lesions but also at NAWM and Location. BBB disruption may be implicated in development of PCS in mTBI patients. (orig.)
[en] By evaluating extent of tumour enhancement on preoperative contrast-enhanced MDCT, we aimed to establish an imaging-based model to predict cancer-specific survival in stage I-III colon cancer. A total of 548 stage I-III colon cancer patients who underwent curative resection from 2007 to 2013 were retrospectively included and divided into primary cohort and validation cohort according to admission time. The attenuation coefficient of each colon cancer was measured on the workstation by drawing the ROI in CT images. The enhancement ratio was calculated using maximum tumour attenuation value in triphasic MDCT scanning divided by the minimum. Patients were divided into low/high-enhancement groups according to the optimal cut-off value derived from time-dependent ROC curve. Kaplan-Meier method and COX regression analysis were adopted to evaluate prognostic value of variables. A nomogram for prognosis was conducted on the basis of a multivariate Cox proportional hazard model. No significant differences were observed in age, sex, pTNM stage, perioperative chemoradiotherapy, serum CEA, tumour size, tumour localisation and histologic type between low- and high-enhancement groups. The high-enhancement group had a significantly shorter cancer-specific survival rate (69.5%) than the low-enhancement group (85.9%) (p 0.001). Subgroup analysis indicated that high-enhancement state was closely associated with increased risk of colon cancer mortality in stage I (p = 0.033), stage II (p = 0.002) and stage III (p = 0.014). Cox regression analysis indicated the extent of enhancement was an independent prognostic factor (HR 2.258, 95% CI 1.476-3.455; p 0.001). The extent of tumour enhancement on MDCT can serve as a potential risk factor for stage I-III colon cancer. (orig.)
[en] Two compounds in the Sc-Co-In system were obtained by arc-melting of the pure metals and their crystal structures have been determined using single crystal X-ray diffraction data. The structure of ScCoIn (space group P, а=7.6702(5), c=3.3595(2) Å, Z=1, R=0.0160, wR=0.0301) belongs to the LuCoIn type structure, which is closely related to the ZrNiAl and LuCoGa types. The structure of ScCoIn (space group P4/nmm, а=12.8331(1), c=9.0226(1) Å, Z=2, R=0.0203, wR=0.0465) belongs to the HoNiIn type, which is closely related to HfNiGa.