Demonstrating the steady performance of iron oxide composites over 2000 cycles at fast charge-rates for Li-ion batteries.

The feasibility of using iron oxides as negative electrode materials for safe high-power Li-ion batteries is demonstrated by the carbon-coated FeOx/CNT composite synthesized by controlled pyrolysis of ferrocene, which delivered a specific capacity retention of 84% (445 mA h g(-1)) after 2000 cycles at 2000 mA g(-1) (4C).

[Complications due to contrast agent administration: what has been confirmed in prevention?]. / Komplikationen durch die Kontrastmittelgabe: Was ist gesichert in der Prävention?

Computed tomography (CT) and magnetic resonance imaging (MRI) have been evaluated by internists to be the most important medical innovations. Often, intravenous contrast agent administration is required for answering the clinical questions to CT and MRI. In this review we present an overview of the most common and most important aspects that need to be considered prior to intravenous contrast agent administration. We discuss aspects of renal impairment (contrast-induced nephropathy, nephrogenic systemic fibrosis), allergy-like reactions, hyperthyroidism, and pregnancy and breast-feeding.

A new dual-purpose ultrahigh vacuum infrared spectroscopy apparatus optimized for grazing-incidence reflection as well as for transmission geometries.

A newly designed ultrahigh vacuum (UHV) infrared spectroscopy apparatus dedicated to the spectroscopic characterization of oxides, singles crystals as well as powders, is described. It combines a state-of-the-art vacuum Fourier transform infrared (FTIR) spectrometer (Bruker, VERTEX 80v) with a novel UHV system (PREVAC) consisting of load-lock, distribution, measurement, and magazine chambers. The innovative design allows carrying out both reflection-absorption IR spectroscopy experiments at grazing incidence on well-defined oxide single crystal surfaces and FTIR transmission measurements for powder particles. A further unique feature of the apparatus is the entirely evacuated optical path to avoid background signals from gas phase H(2)O, CO(2), and other species, thus creating the possibility to record high-quality IR data with high sensitivity and stability, an essential prerequisite for monitoring molecular species adsorbed on oxide single-crystal surfaces. The unique performance of this new apparatus with regard to the spectroscopic characterization of adsorbates on oxide single crystals as well as on powder particles is demonstrated by case studies for two different materials, TiO(2) and ZnO.

[Peripartum changes of the pelvic ring: usefulness of magnetic resonance imaging]. / Peripartale Veränderungen des Beckenringes: Wie sinnvoll ist die Magnetresonanztomografie?

PURPOSE: Postpartum pelvic pain beyond the normal level poses a problem to obstetricians. Beyond normal physiologic loosening of the pubic symphysis and sacroiliac joints (SIJs) during pregnancy, symphyseal separation and rupture must be excluded. The aim of this prospective study was to determine whether magnetic resonance imaging (MRI) allows for reliable differentiation of normal postpartum findings and pathologic lesions. MATERIAL AND METHODS: The study included a total of 77 women (mean age 30), among them 21 healthy subjects (group A), 21 asymptomatic postpartum women (group B), and 35 patients with postpartum pelvic pain (group C). The analyzed parameters comprised symphyseal and iliosacral tenderness, subjective pain assessed on a visual analog scale, and data pertaining to obstetric history. All 77 women underwent 1.5T MRI of the pelvic ring using oblique angulated coronal T 1-weighted and STIR sequences for imaging of the symphysis and SIJs in one slice package. Analysis of the MR images comprised signal intensities of pelvic bone marrow, width of the symphyseal cleft, and the symphyseal capsule. RESULTS: Subjects in group A in general had a normal bone marrow signal. The STIR sequence showed increased signal intensity of the pubic bone near the symphysis in 16 women (76 %) of group B and 31 patients of group C (86 %) (not significant). An increased periarticular bone marrow signal of the SIJs on the STIR images was seen in 13 women (62 %) of group B and 23 patients (63 %) of group C. The mean width of the symphyseal cleft differed significantly among the three groups (3.4 mm vs. 5.4 mm vs. 6.7 mm). A width >10 mm was observed in only 4 cases (11 %). Moreover, associated findings such as interpubic hematoma (n=23) or tears of the symphyseal capsule (n=7) were detected in patients of group C. CONCLUSION: The wide overlap of findings between symptomatic and asymptomatic postpartum patients does not allow reliable differentiation by MRI of normal and abnormal findings. MRI contributes to the differentiation of symphyseal contusion and rupture and provides information on severe associated changes.

Spectroscopic evidence for the partial dissociation of H2O on ZnO(1010).

The interaction of water with the non-polar ZnO(1010) surface has been studied by high resolution electron energy loss spectroscopy (HREELS) and thermal desorption spectroscopy (TDS). Adsorption of water at room temperature leads to the partial dissociation of water molecules giving rise to a well defined (2x1) superstructure. This observation was confirmed by the HREELS data which show the water-induced O-H stretching modes at 396 and 460 meV (3193 and 3709 cm-1) as well as the peak at 456 meV (3677 cm-1) arising from the OH species. The large red shift of the loss at 396 meV indicates unusually strong hydrogen bonding interactions of water to both neighbouring adsorbate molecules and the surface O atoms which are responsible for the partial dissociation of water molecules on the perfect ZnO(1010) surface.

The influence of strongly reducing conditions on strong metal-support interactions in Cu/ZnO catalysts used for methanol synthesis.

A systematic series of binary and ternary copper catalysts was investigated using the methanol synthesis reaction at atmospheric pressure. Strong metal-support interactions between copper and zinc oxide induced by strongly reducing conditions were probed by the adsorption of carbon monoxide, which was monitored qualitatively and quantitatively by a combination of microcalorimetry, temperature-programmed desorption experiments and Fourier transform infrared spectroscopy. For the zinc oxide-containing catalysts, the pretreatment in flowing carbon monoxide at 493 K resulted in a severe decoration of the copper metal particles with ZnOx adspecies, whereas after methanol synthesis at 493 K the state of the copper was essentially identical to that seen after hydrogen reduction. Copper was always found to be present in its zero-valent state.

Microkinetic modeling of CO TPD spectra using coverage dependent microcalorimetric heats of adsorption.

CO adsorption on the ternary methanol synthesis Cu/ZnO/Al2O3 catalyst was studied in detail by means of adsorption microcalorimetry and flow temperature-programmed desorption (TPD). Based on these experimental data, we established a microkinetic analysis method, which provides information about the adsorption kinetics of CO on the catalyst surface. Experimentally derived microcalorimetric heats of adsorption were applied in a microkinetic model to simulate TPD curves with varying initial coverage. Two approaches were used: an integral approach based on evaluation of the integral heats of adsorption which predicts the experimental TPD curves roughly and provides first approximations for the preexponential factors. The second, more detailed approach was based on the simulation of the adsorption isotherm taking the experimentally determined coverage-dependence of the heat of adsorption into account. This approach led to a significantly improved agreement between experimental and simulated TPD curves. Moreover, it was possible to derive the standard entropy of adsorption. The general applicability of our approaches is demonstrated by analyzing the CO TPD and microcalorimetry data obtained with a binary ZnO-free Cu/Al2O3 catalyst.

[How safe is magnetic resonance imaging in patients with contraceptive implants?]. / Wie sicher ist die MRT bei Patientinnen mit kontrazeptiven Implantaten?

When patients with an implanted contraceptive device undergo MRI, it must be ensured that the examination involves no risk to the patient (MR safety) and that the diagnosis is not affected by artifacts or the function of the device compromised (MR compatibility). Two basic types of intrauterine devices can be distinguished: the metal-containing/metal-free intrauterine device (IUD) and the hormone-containing implant, the fully metal-free intrauterine system (IUS), as well as the ESSURE insert made of stainless steel, which has been approved for use in Europe since February 2001. The metal-containing and metal-free IUDs and ESSURE are MRI compatible up to a magnetic field strength of 1.5 T. They do not interact in any relevant way with the external magnetic or high-frequency field and the temperature increase is within the physiologic range. The implants merely produce a local signal void with a shape that depends on their orientation relative to the magnetic field lines. At 3 T, only the metal-free IUD and the IUS are MRI safe in terms of the material used. In contrast, metal-containing IUDs and the ESSURE have not yet been fully evaluated in the 3 T field, which is why they represent a contraindication to MRI. No data are available on the MRI compatibility at 3 T for any of these devices.

[A new method for standardized diagnosis following renal transplantation. Ultrasound with contrast enhancement]. / Eine neue Methode zur standardisierten Diagnostik nach Nierentransplantation. Die ultraschallkontrastmittelgestützte Sonografie.

Ultrasound (US) imaging is an important diagnostic tool following renal transplantation. Unfortunately, due to the heterogeneity of the recipients and their multimorbidity, imaging procedures in the early phase after kidney transplantation are difficult and of limited use. We performed a study to evaluate the use of a contrast enhancer for US examination as a standardized method in the follow-up of kidney transplant recipients.The study included 40 recipients: 32 were examined on the 5th to 7th day following transplantation and 8 patients at the time when clinically suspicious findings occurred (acute rejection, tumor, acute tubular necrosis). Following the intravenous application of the contrast medium, pictures were taken during the arterial and parenchymatous phase and compared with conventional B-mode and power Doppler pictures of the same visual plane. Three examiners assessed different parameters of the transplant organ (max. vascularized area, suspected hematomas, tumors, rejection, acute tubular necrosis). Findings were confirmed by histological results of a biopsy if rejection, tumor, or acute tubular necrosis were suspected. Application of ultrasound contrast medium significantly increased visualization of the vascularized kidney area. Also, US findings in the follow-up after acute rejection therapy corresponded with the clinical course; 19 hematomas could be detected with contrast medium compared to only 9 without. With contrast medium a perfusion deficit was detectable in three patients compared to one patient with power Doppler US. Also, US contrast medium helped to detect tumor vascularization in two patients in whom conventional sonography suspected no abnormality. Ultrasound contrast medium enhancement is a reproducible, reliable, and easy to apply method which is superior to conventional sonography in the follow-up after kidney transplantation. This method is also helpful to detect and control acute rejections and to better visualize hematomas, deficits of perfusion, and tumors.

Redox chemistry of Cu colloids probed by adsorbed CO: an in situ attenuated total reflection Fourier transform infrared study.

The IR spectroscopic investigation of both the adsorption of carbon monoxide and the interaction of oxygen and CO on the surface of copper colloids is described for the first time. The copper colloids were produced by pyrolysis of [Cu(OCH(Me)CH(2)NMe(2))(2)] in hot n-hexadecylamine. Upon contact to synthetic air Cu/Cu(x)O core-shell particles are formed. The treatment of these particles with CO results in the reestablishment of pure Cu(0) particles. These results demonstrate that small molecules penetrate the ligand shell of the nanoparticles and reversibly adsorb at the surface without affecting the particle morphology and size distribution.

Early postoperative ultrasound of kidney transplants: evaluation of contrast medium dynamics using time-intensity curves.

OBJECTIVE: To evaluate kidney recipients in the early posttransplant phase by semiquantitative analysis of the arterial arrival of ultrasound (US) contrast medium using time-intensity curves. PATIENTS AND METHODS: Twenty-two kidney recipients underwent US examination after intravenous bolus administration of 2.4 ml of US contrast medium (SonoVue, Bracco Altana) 5 to 7 days after transplantation. The examinations were performed with the Aplio US system (Toshiba) and a 3.5-MHz wideband transducer using contrast harmonic imaging at a low mechanical index of 0.1. Arterial arrival was documented digitally over 60 sec (image repetition rate: 10 images per sec) for subsequent evaluation of contrast medium kinetics in the main renal artery, interlobar artery, subcapsular area, and renal vein using the system's integrated time-intensity curve (TIC) software. The increase, decrease, and percentage enhancement factor were calculated from the curves. Four patients were excluded from analysis because of perirenal hematoma (n = 3) or a polar perfusion loss demonstrated by power Doppler (n = 1). RESULTS: Twelve of the remaining 18 patients assigned to the nonrejection group showed an uneventful clinical course. These had uniform TICs with an early and steep increase of similar magnitude in the main renal artery (11.7 +/- 4.5 intensity units/sec), interlobar artery (8.7 +/- 4.6 intensity units/sec), and subcapsular area (8.3 +/- 3.7 intensity units/sec) followed by a washout and subsequent plateau phase. Six patients showed histologically proven acute rejection on day 5 or 6 after transplantation (rejection group). This group had a delayed (time to peak in the subcapsular area: 32.9 +/- 8.3 sec in the rejection group versus 20.9 +/- 4.7 sec in the nonrejection group, p < 0.05) and smaller subcapsular percentage increase (41.2 +/- 21.9 % versus 114.4 +/- 59.8 %, p < 0.05). In the rejection group the subcapsular area (3.8 +/- 2.3 intensity units/sec) showed a less pronounced increase than the main renal artery (7.9 +/- 5.9 intensity units/sec) and interlobar artery (8.7 +/- 3.8 intensity units/sec). The RI in the rejection group was in the normal range at the time of contrast-enhanced US (day 5: 0.78 +/- 0.06) and increased to abnormal levels in the further course (day 7: 0.94 +/- 0.09). CONCLUSIONS: Quantitative determination of arterial arrival of an US contrast medium in the early phase after kidney transplantation is possible. This new US procedure might identify acute rejection earlier than conventional techniques.

[Use of state-of-the-art ultrasound techniques in diagnosing sarcoidosis of the salivary glands (Heerfordt's syndrome)]. / Einsatz moderner Ultraschallverfahren in der Diagnostik der Speicheldrüsensarkoidose (Heerfordt-Syndrom).

AIM: The parotid gland is a rare site of sarcoidosis (6% of all cases). The role of state-of-the-art ultrasound techniques in the diagnostic assessment of parotid sarcoidosis (Heerfordt's syndrome) is presented. PATIENTS AND METHODS: Four patients (three male, one female; aged 31-42 years) with inconclusive parotid swelling associated with fever and uveitis were referred for diagnostic assessment by the ENT outpatient service over a 1 year period. High-resolution ultrasound (US) was performed using the SONOLINE Elegra system with a 7.5-MHz wide-band transducer and various, special US techniques (tissue harmonic imaging, photopic imaging, color-coded duplex US, and power Doppler). Diagnoses were confirmed in all cases by puncture and histology. RESULTS: Two patients with typical lung findings (stage I and II sarcoidosis) and two patients without known sarcoidosis showed an inhomogeneous nodular appearance of the clinically enlarged salivary glands at US. Duplex US demonstrated hypervascularization in three cases and moderate, inhomogeneous vascularization in one. In comparison to plain B-mode scanning, optimal visualization of the hypodense, nodular, structural changes was achieved using contrast-enhancing techniques. All patients underwent US-guided puncture for determining the etiology of parotitis. Histology demonstrated granulomatous epitheloid cell inflammation. CONCLUSION: An inhomogeneous nodular appearance of the parenchyma of enlarged parotid glands with areas of hypervascularization, which is optimally depicted by state-of-the-art US techniques, should suggest Heerfordt's syndrome as a possible differential diagnosis.

Adsorptive removal of methylene blue from colored effluents on fuller's earth.

The adsorption behavior of methylene blue (MB) on four fuller's earth (FE) samples of varying compositions was investigated using a spectrophotometric technique to obtain information on the color removal. The distribution coefficient (K(D)) increased with an increase in the initial concentration (C(0)) of the dye, attained a maximum value, and decreased again at higher initial concentrations. Dye solutions became colorless for a C(0) value corresponding to maximum K(D). A progressively increased flocculation behavior in the clay suspensions was observed and the maximum value of K(D) corresponds to optimum flocculation of the clay. The K(D) values were found to decrease exponentially after of the solution again became colored while the amount adsorbed increased with an increase in the initial concentration of MB. Only adsorption data obtained for this region could be defined by adsorption isotherm equations. The shifts of the C(0) values corresponding to K(D)(max) toward higher concentrations were correlated with the composition of FE samples by using XRF, XRD patterns, and SEM images. The influence of temperature on MB adsorption was also studied and thermodynamic parameters were calculated.

[Ultrasound at the bedside: does a portable ultrasound device save time?]. / Sonographie am Krankenbett: Zeitgewinn durch Nutzung eines tragbaren Ultraschallgerätes?

AIM: To prospectively determine whether the use of a portable ultrasound device results in a detectable reduction of the time required for acute ultrasound (US) assessment at the bedside. MATERIALS AND METHODS: A total of 125 patients underwent US at the bedside, among them 68 for abdominal assessment, 12 patients for chest or soft-tissue evaluation, and 45 patients with vascular disease. Five different US systems equipped with 3.5 MHz and 7.5 MHz wide-band transducers were compared in terms of overall examination time including transport, setting up and disassembling, switching on and off as well as initializing the device (but without writing of the report). The following ultrasound systems were used: the portable SonoSite 180 (SonoSite, Germany) as well as the mobile units Masters/Gateway 2000 (Diasonics, USA), Tosbee (Toshiba, Japan), PowerVision 7000 (Toshiba, Japan), and SONOLINE Elegra (Siemens AG, Germany). RESULTS: The portable ultrasound device significantly reduced the examination time per patient to a mean 16 +/- 4 min from 26 +/- 5 min for the mobile units (p < 0.05). This result was predominantly affected by the time required for switching on and initializing the device as well as the duration of positioning at the bedside and to a lesser extent by elevator waiting time. CONCLUSION: The overall time required for performing an ultrasound examination at the bedside can be considerably reduced if a portable device is used instead of a mobile system.

A new polysaccharide macromolecular contrast agent for MR imaging: biodistribution and imaging characteristics.

The aims of this study were to characterize certain physicochemical, pharmacokinetic, and enhancement properties of a new macromolecular contrast agent, carboxymethyl hydroxyethyl starch-(Gd-DO3A)(35) [CMHES-(Gd-DO3A)(35)], consisting of a polysaccharide backbone covalently derivatized with multiple macrocyclic chelating groups for gadolinium. CMHES-(Gd-DO3A)(35) has an average molecular weight of 72 kD and a plasma half-time of 8.4 hours. T1 and T2 relaxivities are 14.1 +/- 0.1 L mmol(-1) * sec(-1) and 17.8 +/- 0.9 L mmol(-1) * sec(-1), respectively, for each gadolinium ion measured at 39 degrees C and 20 Mhz; this T1 relaxivity is more than 4 times that of gadopentetate. Seven days after intravenous administration only relatively small amounts of gadolinium could be detected in blood or other tissues of rats. The compound was well tolerated in diagnostic dosages by all experimental animals. Magnetic resonance angiography performed within 1 hour of CMHES-(Gd-DO3A)(35) administration showed a near-constant and strong enhancement of blood in arteries and veins. Analysis of dynamic enhancement patterns of experimental tumors (MAT-LyLu prostate cancer implanted in rats) following intravenous CMHES-(Gd-DO3A)(35) administration yielded quantitative estimates of tumor plasma volume and microvessel permeability; the demonstrated hyperpermeability of tumor microvessels was easily distinguished from the absence of measurable microvascular permeability in non-neoplastic soft tissues.

Induction of remission in Wegener's granulomatosis with low dose methotrexate.

OBJECTIVE: To study the efficacy of methotrexate (MTX) plus low dose corticosteroids for induction of remission in generalized Wegener's granulomatosis (WG) and to possibly identify predictive factors for the outcome under this therapy. METHODS: We conducted a prospective, open label study, including 17 patients with not immediately life threatening, generalized WG. Treatment consisted of intravenous MTX 0.3 mg/kg once weekly plus daily oral low dose prednisone for initial diagnosis of WG in 11 and for a generalized relapse of WG in 6 patients. Interdisciplinary, standardized assessments of disease activity and extent were done 3-monthly. RESULTS: Within a median treatment period of 24.5 months remission could be achieved in 10/17 patients (59%), their median corticosteroid dose during that time was 1.75 mg/day. Seven patients with a median concomitant prednisone dose of 7.5 mg/day did not respond, among them 4 patients who were treated for a relapse of WG. Signs of de novo glomerulonephritis occurred in 5 of the 7 nonresponders. Significant side effects, including opportunistic infections, did not occur. CONCLUSION: Weekly low dose MTX in combination with low dose corticosteroids leads to an acceptable remission rate of almost 60% without significant side effects. Patients treated for a relapse of WG and patients with a need for a higher concomitant prednisone dose seem to be at risk for nonresponse, with a high likelihood of developing de novo glomerulonephritis.