[Use of monoclonal antibodies in pathological diagnostics]

In pathological diagnostics, monoclonal antibodies (mAb) are mainly used for immunhistochemical analysis. After an initial histological evaluation, a precise panel of antibodies is selected in order to stain the slides by using an indirect immune method. The most frequent issues include localisation of the primary tumor in cases of metastases, determination of undifferentiated tumors, subtyping of lympho-proliferative diseases and soft tissue tumors, as well as the assessment of proliferation via Ki-67. Increasing importance in mAb-based diagnostics is attributed to the analysis of predictive biomarkers such as hormone receptors, mismatch repair proteins (MMR) and programmed death ligand 1 (PD-L1). Their evaluation is performed by using different scores, which the clinical physician needs to be aware of due to their direct therapeutic implications.

A C/EBPα-Wnt connection in gut homeostasis and carcinogenesis

This research reveals an antagonism between C/EBPα expression and activated Wnt signaling in the human and mouse gut and suggests a tumor suppressor function of C/EBPα in human and murine intestinal cancer.

We explored the connection between C/EBPα (CCAAT/enhancer-binding protein α) and Wnt signaling in gut homeostasis and carcinogenesis. C/EBPα was expressed in human and murine intestinal epithelia in the transit-amplifying region of the crypts and was absent in intestinal stem cells and Paneth cells with activated Wnt signaling. In human colorectal cancer and murine APC^Min/+ polyps, C/EBPα was absent in the nuclear β-catenin–positive tumor cells. In chemically induced intestinal carcinogenesis, C/EBPα KO in murine gut epithelia increased tumor volume. C/EBPα deletion extended the S-phase cell zone in intestinal organoids and activated typical proliferation gene expression signatures, including that of Wnt target genes. Genetic activation of β-catenin in organoids attenuated C/EBPα expression, and ectopic C/EBPα expression in HCT116 cells abrogated proliferation. C/EBPα expression accompanied differentiation of the colon cancer cell line Caco-2, whereas β-catenin stabilization suppressed C/EBPα. These data suggest homeostatic and oncogenic suppressor functions of C/EBPα in the gut by restricting Wnt signaling.

Dynamics in the Plastic Crystalline Phases of Cyclohexanol and Cyclooctanol Studied by Quasielastic Neutron Scattering

Plastic crystals are a promising candidate for solid state ionic conductors. In this work, quasielastic neutron scattering is employed to investigate the center of mass diffusive motions in two types of plastic crystalline cyclic alcohols: cyclohexanol and cyclooctanol. Two separate motions are observed which are attributed to long-range translational diffusion (α-process) and cage rattling (fast β-process). Residence times and diffusion coefficients are calculated for both processes, along with the confinement distances for the cage rattling. In addition, a binary mixture of these two materials is measured to understand how the dynamics change when a second type of molecule is added to the matrix. It is observed that, upon the addition of the larger cyclooctanol molecules into the cyclohexanol solution, the cage size decreases, which causes a decrease in the observed diffusion rates for both the α- and fast β-processes.

Cross-validation of survival associated biomarkers in gastric cancer using transcriptomic data of 1,065 patients

Introduction

Multiple gene expression based prognostic biomarkers have been repeatedly identified in gastric carcinoma. However, without confirmation in an independent validation study, their clinical utility is limited. Our goal was to establish a robust database enabling the swift validation of previous and future gastric cancer survival biomarker candidates.

Results

The entire database incorporates 1,065 gastric carcinoma samples, gene expression data. Out of 29 established markers, higher expression of BECN1 (HR = 0.68, p = 1.5E-05), CASP3 (HR = 0.5, p = 6E-14), COX2 (HR = 0.72, p = 0.0013), CTGF (HR = 0.72, p = 0.00051), CTNNB1 (HR = 0.47, p = 4.3E-15), MET (HR = 0.63, p = 1.3E-05), and SIRT1 (HR = 0.64, p = 2.2E-07) correlated to longer OS. Higher expression of BIRC5 (HR = 1.45, p = 1E-04), CNTN1 (HR = 1.44, p = 3.5E- 05), EGFR (HR = 1.86, p = 8.5E-11), ERCC1 (HR = 1.36, p = 0.0012), HER2 (HR = 1.41, p = 0.00011), MMP2 (HR = 1.78, p = 2.6E-09), PFKB4 (HR = 1.56, p = 3.2E-07), SPHK1 (HR = 1.61, p = 3.1E-06), SP1 (HR = 1.45, p = 1.6E-05), TIMP1 (HR = 1.92, p = 2.2E- 10) and VEGF (HR = 1.53, p = 5.7E-06) were predictive for poor OS.

MATERIALS AND METHODS

We integrated samples of three major cancer research centers (Berlin, Bethesda and Melbourne datasets) and publicly available datasets with available follow-up data to form a single integrated database. Subsequently, we performed a literature search for prognostic markers in gastric carcinomas (PubMed, 2012–2015) and re-validated their findings predicting first progression (FP) and overall survival (OS) using uni- and multivariate Cox proportional hazards regression analysis.

Conclusions

The major advantage of our analysis is that we evaluated all genes in the same set of patients thereby making direct comparison of the markers feasible. The best performing genes include BIRC5, CASP3, CTNNB1, TIMP-1, MMP-2, SIRT, and VEGF.

Observation and Structure Determination of an Oxide Quasicrystal Approximant

We report on the first observation of an approximant structure to the recently discovered two-dimensional oxide quasicrystal. Using scanning tunneling microscopy, low-energy electron diffraction, and surface x-ray diffraction in combination with ab initio calculations, the atomic structure and the bonding scheme are determined. The oxide approximant follows a 3^{2}.4.3.4 Archimedean tiling. Ti atoms reside at the corners of each tiling element and are threefold coordinated to oxygen atoms. Ba atoms separate the TiO_{3} clusters, leading to a fundamental edge length of the tiling 6.7 Å.

C/EBPβ regulates homeostatic and oncogenic gastric cell proliferation

Abstract

Cancer of the stomach is among the leading causes of death from cancer worldwide. The transcription factor C/EBPβ is frequently overexpressed in gastric cancer and associated with the suppression of the differentiation marker TFF1. We show that the murine C/EBPβ knockout stomach displays unbalanced homeostasis and reduced cell proliferation and that tumorigenesis of human gastric cancer xenograft is inhibited by knockdown of C/EBPβ. Cross-species comparison of gene expression profiles between C/EBPβ-deficient murine stomach and human gastric cancer revealed a subset of tumors with a C/EBPβ signature. Within this signature, the RUNX1t1 tumor suppressor transcript was down-regulated in 38 % of gastric tumor samples. The RUNX1t1 promoter was frequently hypermethylated and ectopic expression of RUNX1t1 in gastric cancer cells inhibited proliferation and enhanced TFF1 expression. These data suggest that the tumor suppressor activity of both RUNX1t1 and TFF1 are mechanistically connected to C/EBPβ and that cross-regulation between C/EBPβ-RUNX1t1-TFF1 plays an important role in gastric carcinogenesis.

Key message

C/EBPβ controls proliferation and differentiation balance in the stomach.

Homeostatic differentiation/proliferation balance is altered in gastric cancer.

RUNX1t1 is a C/EBPβ-associated tumor suppressor.

RUNX1t1 negatively regulates C/EBPβ pro-oncogenic functions.

Electronic supplementary material

The online version of this article (doi:10.1007/s00109-016-1447-7) contains supplementary material, which is available to authorized users.

MACC1 Induces Tumor Progression in Transgenic Mice and Colorectal Cancer Patients via Increased Pluripotency Markers Nanog and Oct4

PURPOSE

We have previously identified the gene MACC1 as a strong prognostic biomarker for colorectal cancer metastasis and patient survival. Here, we report for the first time the generation of transgenic mouse models for MACC1.

EXPERIMENTAL DESIGN

We generated mice with transgenic overexpression of MACC1 in the intestine driven by the villin promoter (vil-MACC1) and crossed them with Apc(Min) mice (vil-MACC1/Apc(Min)).

RESULTS

vil-MACC1/Apc(Min) mice significantly increased the total number of tumors (P = 0.0056). This was particularly apparent in large tumors (≥3-mm diameter; P = 0.0024). A detailed histopathologic analysis of these lesions demonstrated that the tumors from the vil-MACC1/Apc(Min) mice had a more invasive phenotype and, consequently, showed a significantly reduced survival time than Apc(Min) mice (P = 0.03). Molecular analysis revealed an increased Wnt and pluripotency signaling in the tumors of vil-MACC1/Apc(Min) mice. Specifically, we observed a prominent upregulation of the pluripotency markers Oct4 and Nanog in these tumors compared with Apc(Min) controls. Finally, we could also validate that Oct4 and Nanog are regulated by MACC1 in vitro and strongly correlate with MACC1 levels in a cohort of 60 tumors of colorectal cancer patients (r = 0.7005 and r = 0.6808, respectively; P > 0.0001 and P > 0.0002, respectively).

CONCLUSIONS

We provide proof of principle that MACC1-induced tumor progression in colorectal cancer acts, at least in part, via the newly discovered MACC1/Nanog/Oct4 axis. These findings might have important implications for the design of novel therapeutic intervention strategies to restrict tumor progression. Clin Cancer Res; 22(11); 2812-24. ©2016 AACR.

[Inguinal Hernia Repair According to Desarda - Implementation of a Mesh-Free Method in a German University Hospital]

Inguinal hernia repair shows a clear tendency towards mesh-based as well as laparoscopic approaches. This is widely reflected in data-based statistics and guidelines. In contrast we have initiated and hereby illustrate the surgical method according to Desarda using autologous fascia to repair inguinal hernia.

[Loss of domain-a surgeon's challenge. Surgical approach to an enormous scrotal hernia]

We report on the one-stage procedure surgical approach to an enormous scrotal hernia bearing the whole small bowel and part of the large bowel as a loss of domain situation. Using a mesh-based component separation abdominal wall technique according to Ramirez we managed to retrieve the hernia content into the abdominal cavity allowing reduction of the resulting intra-abdominal pressure. We present our surgical approach in detail and report on the postoperative process based on focused intensive care surveillance and specific surgical complication management leading to hospital discharge of the patient on postoperative day 57.

[CAMIC Recommendations for Surgical Laparoscopy in Non-Obstetric Indications during Pregnancy]

In the operative surgical primary care, the laparoscopic surgical technique has firmly established itself in recent years. Meanwhile, in the normal population over 90 % of all cholecystectomies and over 80 % of all appendectomies are performed in a minimally invasive manner. The proven benefits of the laparoscopic surgical technique, compared with conventional open surgery, are a comparatively rapid early postoperative recovery with early resumption of the general physical and occupational activity. As these benefits are equally applicable for necessary interventions during pregnancy, in recent years laparoscopy has become the preferred treatment for non-obstetric indications in the gravid patient. Overall, it can be assumed that such interventions have to be performed in approximately 2 % of all pregnant patients. Numerous studies have proven here that the use of laparoscopic techniques, in particular for the expectant mother, is safe and not associated with an increased risk. On the other hand, the current pregnancy makes necessary an adapted approach to the solution of surgical problems to ensure the protection of the unborn child. On the basis of currently available data situation, recommendations are formulated which can be used as a decision-making support for a variety of clinical situations.

Prediction of glioma recurrence using dynamic ¹⁸F-fluoroethyltyrosine PET

BACKGROUND AND PURPOSE

Inter- and intratumor heterogeneity and the variable course of disease in patients with glioma motivate the investigation of new prognostic factors to optimize individual treatment. Here we explore the usefulness of standard static and more sophisticated dynamic (18)F-fluoroethyltyrosine-PET imaging for the assessment of patient prognosis.

MATERIALS AND METHODS

Thirty-four consecutive patients with untreated, first-diagnosed, histologically proved glioma were included in this retrospective study. All patients underwent dynamic PET scans before surgery (± standard treatment) and were followed up clinically and by MR imaging. Static and dynamic tumor-to-background ratio, TTP, and slope-to-peak were obtained and correlated with progression-free survival.

RESULTS

Twenty of 34 patients experienced progression, with a median progression-free survival of 28.0 ± 11.1 months. Dynamic TTP was highly prognostic for recurrent disease, showing a strong correlation with progression-free survival (hazard ratio, 6.050; 95% CI, 2.11-17.37; P < .001). Most interesting, this correlation also proved significant in the subgroup of low-grade glioma (hazard ratio, 5.347; 95% CI, 1.05-27.20; P = .044), but not when using established static imaging parameters, such as maximum tumor-to-background ratio and mean tumor-to-background ratio. In the high-grade glioma subgroup, both dynamic and static parameters correlated with progression-free survival. The best results were achieved by defining ROIs around "hot spots" in earlier timeframes, underlining the concept of intratumor heterogeneity.

CONCLUSIONS

(18)F-fluoroethyltyrosine-PET can predict recurrence in patients with glioma, with dynamic analysis showing advantages over static imaging, especially in the low-grade subgroup.

Hydrogels from phospholipid vesicles

It is shown that phospholipid dispersions with a few percent of diacylphosphocholine PC in water can be swollen to single-phase lyotropic liquid crystalline Lα-phases by the addition of co-solvents like glycerol, 1,3-butyleneglycol BG or 1,2-propyleneglycol PG. The birefringent Lα-phases contain small unilamellar and multilamellar vesicles if the temperature of the samples is above the Krafft-Temperature Tm of the phospholipid. When such transparent birefringent viscous samples are cooled down below Tm the samples are transformed into birefringent gels. Cryo-TEM and FF-TEM measurements show that the bilayers of the vesicles are transformed from the liquid to the crystalline state during the transformation while the vesicle structure remains. The bilayers of the crystalline vesicles form adhesive contacts in the gel. Pulsed-field gradient NMR measurements show that two different kinds of water or co-solvent can be distinguished in the gels. One type of solvent molecules can diffuse like normal solvent in a continuous bulk phase. A second type of water diffuses much more slowly. This type of solvent is obviously trapped in the vesicles. The permeability of the crystalline vesicles for water and solvent molecules is much lower in the crystalline state than in the fluid state. Maximum swelling of the diacylphosphocholin dispersions occurs when the refractive index of the solvent is matched to the refractive index of the bilayers. The attraction between the bilayers is at a minimum in this state and the liquid crystalline Lα-phase's undulation forces between the bilayers push the bilayers apart. On transformation to the gel state the crystalline bilayers assume a high elastic bending rigidity. Undulations of the bilayers are now suppressed, and the bilayers can form adhesive contacts. Oscillating rheological measurements show that the gels with only 1% of phospholipids can have a storage modulus of 1000Pa. The gels are very brittle. They break when they are deformed by a few percent.

[PET-MR in patients with glioblastoma multiforme]

Glioblastoma multiforme (GBM) is the most common and most aggressive primary tumor of the brain. In recent years newer therapeutic approaches have been developed. To allow for an optimized treatment planning it is important to precisely delineate necrotic tissue, edema and vital tumor tissue and to identify the most aggressive parts of the GBM. The magnetic resonance (MR) portion of an MR-positron emission tomography (PET) examination in patients with GBM should consist of both structural and functional sequences including diffusion-weighted and perfusion sequences. The use of (18)F-fluorodeoxyglucose ((18)F-FDG) is limited in patients with gliomas as glucose metabolism is already physiologically high in parts of the brain but (18)F-FDG is nevertheless a commonly used radiopharmaceutical for neuro-oncological questions. (18)F-fluorothymidine reflects the cellular activity of thymidine kinase 1 and correlates with the expression of KI-67 as an index of mitotic activity. The nitroimidazole derivatives (18)F-fluoromisonidazole and (18)F-fluoroazomycin arabinoside ((18)F-FAZA) allow the detection of hypoxic areas within the tumor. In recent years amino acid tracers, such as (18)F-fluoroethyltyrosine are increasingly being used in the diagnosis of gliomas. The simultaneous PET-MR image acquisition allows new approaches, e.g. motion correction by the simultaneous acquisition of MR data with a high temporal resolution and an improved quantification of the PET signal by integrating the results of functional MR sequences. Moreover, the simultaneous acquisition of these two time-consuming methods leads to reduced imaging times for this, often severely ill patient group.

[The White man's burden - a case study caught between bipolar affective disorder and Huntington's disease]

We report upon a case of a 55 year old patient with a bipolar affective disorder, presenting herself with a depressive symptomatology in addition to a severe motor perturbation. The main emphasis upon admittance was perfecting and improving her latest medication. Four weeks prior to her stay at our clinic a thorough neurological examination had taken place in terms of an invalidity pension trial which did not result in any diagnostic findings. Therefore a neurological disease seemed at first highly unlikely. Even though the prior testing was negative, the ensuing neurological examination at our clinic resulted in movement disorders very much indicative of Huntington's Disease. A detailed investigation in regards to the particular family history of the patient was positive for Huntington's Disease. However, whether the patient's mother had also been a genetic carrier of Huntington's Disease was still unknown at the time the patient was admitted to our clinic. It was nevertheless discovered that her mother had also suffered from a bipolar affective disorder. A genetic testing that followed the neurological examination of the patient proved positive for Huntington's Disease. Neuro-imaging resulted in a bicaudate-index of 2.4 (the critical value is 1.8). In a clinical psychological test battery the ensuing results were highly uncommon for patients with solely a bipolar affective disorder people. Under the medical regimen of Quetiapine, Citalopram and Tiaprid the patient's mood could be stabilized and there was some improvement of her motor pertubation.

Calculation of scattering-patterns of ordered nano- and mesoscale materials

Analytical expressions for the scattering patterns of ordered nano- and mesoscopic materials are derived and compared to measured scattering patterns. Ordered structures comprising spheres (fcc, bcc, hcp, sc, and bct), cylinders (hex and sq), lamellae (lam) and vesicles, as well as bicontinuous cubic structures (Ia3d, Pn3m, and Im3m) are considered. The expressions take into account unit cell dimensions, particle sizes and size distributions, lattice point deviations, finite domain sizes, orientational distributions, core/shell-structures as well a variety of peak shapes. The expressions allow to quantitatively describe, model and even fit measured SAXS and SANS-patterns of ordered or oriented micellar solutions, lyotropic phases, block copolymers, colloidal solutions, nanocomposites, photonic crystals, as well as mesoporous materials.

Surface-induced breakout crystallization in cylinder-forming P(I-b-EO) diblock copolymer thin films

We have found very slow crystallization in thin films of cylinder-forming poly(isoprene-b-ethyleneoxide) (P(I-b -EO)) diblock copolymers with PEO being the minority block. The film was crystallized at room temperature after melting at 62 °C. Imaging methods were combined with X-ray reflectometry and grazing-incidence small-angle X-ray scattering and diffraction. Initially, hexagonally packed, amorphous PEO cylinders lie in the film plane. After 148 days, crystallized, finger-like terraces were observed over the entire film surface. The terrace height is 20% higher than the repeat distance in the as-prepared film. Thus, at the film surface, the cylinders have been destroyed by crystalline lamellae lying in the film plane. The PEO chain stems are perpendicular to the substrate surface and are once-folded and fully interdigitated. The substrate-near layers still consist of the hexagonally packed, amorphous PEO cylinders within the PI matrix.

Fever of unknown origin as initial manifestation of large vessel giant cell arteritis: diagnosis by colour-coded sonography and 18-FDG-PET

OBJECTIVES

To evaluate the clinical characteristics and imaging results (CDS, 18-FDG-PET) of patients with large vessel giant cell arteritis (LV-GCA) presenting as fever of unknown origin (FUO).

METHODS

From a series of 82 patients with GCA we identified 8 patients with FUO as initial disease manifestation. Clinical characteristics and results of CDS and 18-FDG-PET were analysed. Patients with FUO and those with other clinical manifestations of GCA were compared.

RESULTS

18-FDG-PET-scans were available for 6/8 patients, revealing enhanced tracer uptake of the thoracic aorta and the aortic branches in all patients. CDS was performed in 8/8 patients, with detection of hypoechogenic wall thickening related to LV-GCA in 7/8 patients. Subjects with FUO were significantly younger (60.9 vs. 69.3 years, p<0.01) and had a stronger humoral inflammatory response (CRP 12.6 vs. 7.1 mg/dl, p<0.01; ESR 110 vs. 71 mm/hour, p<0.01), when compared to the other GCA-patients.

CONCLUSIONS

LV-GCA should be considered as important differential diagnosis in patients with FUO. In addition to 18-FDG-PET, which is known to be a valuable method in the diagnostic work-up of FUO, we recommend CDS of the supraaortal and femoropopliteal arteries for the initial diagnostic work-up.

18F-fluoroethylcholine uptake in arterial vessel walls and cardiovascular risk factors: correlation in a PET-CT study

AIM

Fluorine-labelled choline derivatives were recently suggested as agents for visualizing vulnerable atherosclerotic plaques. We therefore aimed to evaluate the association between18F-fluoroethylcholine (FEC) uptake in the wall of large arteries, where calcification was also measured, with the presence of cardiovascular risk factors and occurrence of prior cardiovascular events.

PATIENTS, METHODS

Detailed clinical information, including common cardiovascular risk factors, was obtained retrospectively in 60 prostate cancer patients examined with whole-body FEC PET-CT. In each patient, we calculated the mean blood pool-corrected SUV, as well as the mean target-to-background ratio (TBR), in addition to the sum of calcified plaques (CPsum) from six major vessels: ascending and descending aorta, aortic arch, abdominal aorta, and both iliac arteries.

RESULTS

As reported previously, the CPsum correlated significantly with cardiovascular risk factors, in contrast to mean SUV or TBR scores, which did not show any significance with the presence of cardiovascular risk factors. There was no correlation between CPsum, mean TBR or SUV, nor was there any significant association of CPsum, mean TBR or SUV with the prior occurrence of cardio- or cerebrovascular events.

CONCLUSION

Contrary to a recent report, we found in our rather large cohort of elderly prostate cancer patients no significant association between FEC uptake in large vessels and atherosclerotic plaque burden, or the presence of cardiovascular risk factors. In line with prior reports on structural changes in vessels, increased calcified atherosclerotic plaque burden was strongly associated with the occurrence of common cardiovascular risk factors.

Scatter: software for the analysis of nano- and mesoscale small-angle scattering

Scatteris a new software for analysis, modeling and fitting of one- and two-dimensional small-angle scattering data of non-ordered, partially ordered or fully ordered nano- and mesoscale structures. The calculations are based on closed analytical expressions for the scattering intensity, enabling efficient evaluation of form factors and structure factors. The software allows one to sequentially fit large series of scattering curves and scattering patterns automatically. It provides further tools for data loading, beam centering, calibration, zooming, binning, lattice identification, calculation of density profiles and size distributions, and visualization of real-space structures. Presentations of experimental and calculated data can be saved as is for presentations or exported for further graphical or mathematical treatment.

PET and SPECT in epilepsy: a critical review

Molecular imaging with ictal and interictal single-photon emission computed tomography (SPECT) as well as positron emission tomography (PET) rank among the established functional imaging tests for the presurgical evaluation of epileptic onset zone in patients with intractable partial epilepsy. In temporal lobe epilepsy the sensitivity of these methods was shown to be excellent, in particular if a multimodal platform is used, which combines the functional imaging with the additional morphological information of magnetic resonance imaging (MRI), but was lower in extra temporal lobe epilepsy. Functional imaging with SPECT and PET reflects seizure related changes of cerebral perfusion, glucose-metabolism and neuroreceptor status. In this review the usefulness of SPECT and PET imaging in clinical routine in epilepsy as well as the role of different neuroreceptor PET-tracer, which were used in epilepsy are discussed. The use of perfusion SPECT tracer allows the investigation of ictal activations, but the low temporal resolution of ictal perfusion SPECT often results in the detection of both the ictal onset zone as well as the propagation pathways, an area that has not always need to be resected in order to render a patient seizure free. The additional use of interictal PET with fluorine-18 fluorodeoxyglucose which measures regional cerebral metabolism or interictal perfusion SPECT enhance the informational value of ictal SPECT and were shown to be important tools to better define the ictal onset and surround inhibition zones. In recent years PET imaging of different cerebral neuroreceptor-systems inter alia GABA(A) receptors, serotonin receptors (5-HT(1A)), opioid receptors as well as dopamine receptors was used to investigate the neurochemical basis of epilepsy, the role of these neurotransmitters for the epileptogenesis as well as the spread of epileptic activity during seizures and partially entered in clinical routine. Currently some of these radioligands are also used to investigate new treatment approaches.

Bundle formation in polyelectrolyte brushes

Bundle formation of the vertically oriented polyelectrolytes within polyelectrolyte brushes is studied with x-ray reflectivity and grazing-incidence diffraction as a function of grafting density and ion concentration. At 0.8 Molar monomer concentration and without added salt, a bundle consists of two chains and is 50 A long. On the addition of up to 1M CsCl, the aggregation number increases up to 15 whereas the bundle length approaches a limiting value, 20 A. We suggest that the bundle formation is determined by a balance between long-ranged electrostatic repulsion, whose range and amplitude is decreased on salt addition, and short-ranged attraction.

Activation and isomerization of n-butane on sulfated zirconia model systems—an integrated study across the materials and pressure gaps

Butane activation has been studied using three types of sulfated zirconia materials, single crystalline epitaxial films, nanocrystalline films, and powders. A surface phase diagram of zirconia in interaction with SO(3) and water was established by DFT calculations, which was verified by LEED investigations on single-crystalline films and by IR spectroscopy on powders. At high sulfate surface densities a pyrosulfate species is the prevailing structure in the dehydrated state; if such species are absent, the materials are inactive. Theory and experiment show that the pyrosulfate can react with butane to give butene, H(2)O and SO(2), hence butane can be activated via oxidative dehydrogenation. This reaction occurred on all investigated materials; however, isomerization could only be proven for powders. Transient and equilibrium adsorption measurements in a wide pressure and temperature range (isobars measured via UPS on nanocrystalline films, microcalorimetry and temporal analysis of products measurements on powders) show weak and reversible interaction of butane with a majority of sites but reactive interaction with <5 micromol g(-1) sites. Consistently, the catalysts could be poisoned by adding sodium to the surface in a ratio S/Na = 35. Future research will have to clarify what distinguishes these few sites.

Interaction of SO3 with c-ZrO2(111) films on Pt(111)

Single-crystalline sulfated c-ZrO2(111) films of the cubic (c) type have been prepared by reactive deposition of Zr onto Pt(111) in an O2 atmosphere and subsequent exposition to a SO3 atmosphere. The morphology, atomic structure, and composition have been examined by scanning tunneling microscopy, low-energy electron diffraction (LEED), Auger electron spectroscopy, and density functional theory (DFT) calculations. The clean c-ZrO2(111) films display a (2x2) surface structure. During SO3 exposure at room temperature, a clear (radical3xradical3)R30 degrees structure develops. At about 700 K, the SO3-induced (radical3xradical3)R30 degrees structure disappears and the bright (2x2) LEED pattern of the clean ZrO2 films reappears. The energies of plausible c-ZrO2(111)/SO3 structures have been examined by DFT. The (radical3xradical3)R30 degrees structure found in the experiments turned out to be the most stable one for temperatures below 700 K. At temperatures around 700 K, a disordered low coverage structure may exist, which can not be observed by conventional LEED. A comparison of cubic zirconia surfaces with the alternative tetragonal system yields similar results for the SO3 adsorption in the DFT calculations and shows that c-ZrO2 surfaces are good models for the industrial used tetragonal ZrO2 supports.

Self-supported particle-track-etched polycarbonate membranes as templates for cylindrical polypyrrole nanotubes and nanowires: an X-ray scattering and scanning force microscopy investigation

Self-supported particle-track-etched polycarbonate membranes with nearly perfect cylindrical pores are used for the preparation of similarly perfect cylindrical polypyrrole nanowires and nanotubes. A complete investigation of the structural properties that result at different stages of the preparation route of polypyrrole nanowires and nanotubes is based on a combination of real and reciprocal space techniques. Nanoporous membranes with nominal pore size ranging from 5 to 150 nm and pore density up to 10(9) pores/cm(2) made from 21-microm-thick polycarbonate films are used. Polypyrrole nanotubes or nanowires are synthesized inside the pores. A real-space picture of the nanomaterial results from scanning force microscopy (SFM) on ultrathin sections made in two directions to obtain structures in the sample surface as well as perpendicular to the surface. From a model-based fit to the small-angle and ultra-small-angle X-ray scattering (SAXS/USAXS) data, the geometric pore structure is obtained and compared to values determined with scanning electron microscopy (SEM). Nanopores, nanowires, and nanotubes are described by uniform solid cylinders or hollow tubes, which are oriented highly parallel to each other and exhibit a small size distribution. Below a critical pore diameter, solid nanowires are produced whereas above this limit hollow nanotubes result.

Islet autotransplantation combined with pancreatectomy for treatment of pancreatic adenocarcinoma: a case report

Extensive pancreatectomy (EP) may increase the resection rate of pancreatic adenocarcinoma (PA). Unfortunately, EP often results in unstable diabetes. Recently, islet autotransplantation (auto-Tx) has offered the potential to prevent this metabolic disorder. Because of the fear of contamination of prepared islets by malignant cells, this procedure has so far not been used as a treatment for PA. We herein report a case of a 63-year-old nondiabetic patient who underwent EP combined with islet auto-Tx in an emergency operation following histologically proved R(0)-resection for PA (pT(3)pN(1)G(2)). Islets were isolated from the excised pancreas using a continuous digestion filtration device. The resultant preparation was injected into the portal vein. Owing to the moderate fasting hyperglycemia, postoperative exogenous insulin therapy was necessary (26 U/d). After discharge, the patient's daily insulin dose was gradually reduced. At 1-year follow-up the fasting C-peptide level was 0.66 ng/mL, and an oral glucose tolerance test (oGTT) and an intravenous (IV) glucagon stimulation (GS) showed functioning engrafted islets. The K-ras mutations were detected in the paraffin-embedded PA, but not in the prepared islets or in the peripheral blood. Computed tomographic (CT) imaging revealed neither local tumor recurrence nor liver metastases. At 2-year follow-up, the patient was on a balanced food regimen and gaining weight. Although he remains insulin-dependent (16 U/d), he is metabolically stable (HbA(1)(c) 5.9%). The fasting C-peptide level is 0.68 ng/mL. The peak value of C-peptide in response to oGTT was 0.92 ng/mL and to GS 0.89 ng/mL. At this time Ca19-9 and CEA are increased to 35.3 U/mL and 19.2 ng/mL, respectively. The patient died 2.5 years after operation owing to tumor recurrence. There was no evidence for liver metastases. We postulate that histologic evaluation (R(0)-resection) and detection of K-ras mutations may be useful techniques. However, islet auto-Tx after EP for adenocarcinoma should only be regarded for rescue therapy. Studies on strategies to exclude possible contamination of islet tissue with carcinoma cells are critically important.

Shear thinning and orientational ordering of wormlike micelles

Shear thinning and orientation of cylindrical surfactant and block copolymer micelles was investigated by rheo-SANS (small-angle neutron scattering) experiments. Shear thinning and orientation occur for shear rates (.)gamma tau(dis)>>1, where tau(dis) is the disentanglement time of the micelles. Micelles align in the flow direction with an orientational distribution that can be well described by an Onsager-type distribution function. Over nearly the whole range of concentrations and for all cylindrical micelles investigated, the shear viscosity eta follows a simple eta approximately e(-aS) behavior as a function of the orientational order parameter S with the same prefactor a.

Scattering Curves of Ordered Mesoscopic Materials

Analytical expressions for the scattering functions of ordered mesoscopic materials are derived and compared to experimentally determined scattering curves. Ordered structures comprising spheres (fcc, bcc, hcp, sc), cylinders (hex, sq), and lamellar structures are considered. The expressions take into account particle size distributions and lattice point deviations, domain size, core/shell structures, as well as peak shapes varying analytically between Lorentzian and Gaussian functions. The expressions allow one to quantitatively describe high-resolution synchrotron small-angle X-ray (SAXS) and neutron scattering (SANS) curves from lipid and block copolymer lyotropic phases, core/shell nanoparticle superstructures, ordered nanocomposites, and ordered mesoporous materials. In addition, the diffuse out-of-plane scattering of grazing incidence GISAXS and GISANS experiments of laterally ordered thin films can be quantitatively analyzed.