bluuebunny/crossref_metadata_2025 huggingface dataset:
Melting during heat treatment of a sheet of a niobium alloy – Failure analysis
Authors: Bhatia D.N. , Rao M.N. , Taneja A.K.
Published: August 2009

The niobium alloy Nb‐5.4 At% Hf‐2 At% Ti is an important structural material used for high temperature applications. It is commonly produced in the form of sheet; however, it is also available in other mill forms. The sheets are vacuum‐annealed to improve the formability prior to fabricating different components out of them through metal forming. Annealing in vacuum is adopted in view of the high proneness to oxidation of niobium‐ base materials. In the present instance vacuum annealing of a sheet of the niobium alloy was carried out at 1175 oC; a plate of the nickel‐base superalloy 600 was used as charge support. It was noticed that the vacuum annealing resulted in melting of the charge as well as the charge support material. The plate of superalloy 600 was then replaced by a sheet of commercially pure titanium and next trial of annealing heat treatment carried out; there was no problem of melting. Failure analysis was carried out. The analysis brings out how phase diagrams can be used to choose the right material for supporting the charge in order to prevent melting during heat treatment. The failure is very expensive, if the material to be heat treated is costly, as it happens to be in the present case.
Nanophase hardfaced coatings
Authors: Reisgen U. , Stein L. , Balashov B. , Geffers C.
Published: August 2009

This paper demonstrates the possibility of producing iron or chromium‐based nanophase hardfaced coatings by means of common arc welding methods (TIG, PTA). The appropriate composition of the alloys to be deposited allows to control the structural properties and thus also the coating properties of the weld metal. Specific variations of the alloying elements allow also the realisation of a nanostructured solidification of the carbides and borides with cooling rates that are common for arc surfacing processes. The hardfaced coatings, which had been thus produced, showed phase dimensions of approximately 100–300 nm. Based on the results it is established that the influence of the surfacing parameters and of the coating thickness and thus the influence of the heat control on the nanostructuring process is, compared with the influence of the alloy composition, of secondary importance. The generation of nanoscale structures in hardfaced coatings allows the improvement of mechanical properties, wear resistance and corrosion resistance. Potential applications for these types of hardfaced coatings lie, in particular, in the field of cutting tools that are exposed to corrosion and wear.
Structure‐property investigations on a laser beam welded dissimilar joint of aluminium AA6056 and titanium Ti6Al4V for aeronautical applications Part I: Local gradients in microstructure, hardness and strength
Authors: Vaidya W.V. , Horstmann M. , Ventzke V. , Petrovski B. , Koçak M. , Kocik R. , Tempus G.
Published: August 2009

Sheets of AA6056 and Ti6Al4V were butt‐joined by inserting the Ti‐sheet into the profiled Al‐sheet and by melting the Al‐alloy alone using a split beam Nd:YAG laser. To study microstructural effects on properties, the Al‐alloy was used in two tempers; T4 followed by post weld heat treatment T6, and in T6 followed by a defined duration of natural ageing at room temperature. As a basic step for fatigue and fracture investigations, local gradients in properties of this dissimilar joint are investigated using microscopy, hardness and tensile tests. Possible sites, from which fracture may initiate, have been then identified. All property changes are found to confine to the aluminium side. An intermetallic layer, although very thin, is found to form on the interface. The changeovers, firstly between the fusion zone and the heat affected zone and secondly between the heat affected zone and the base material, are found to be associated with changes in microstructure, hardness and strength. These are identified as the possible critical sites in addition to the interface.
Production new chelating fibers of polyacrilonitrile for removing metal ions
Authors: Tabarzadi M. , Abdouss M. , Javanbakht M. , Shoshtary S.A.M. , Zargaran M. , Dashtizadeh A.
Published: August 2009

In this work, raw acrylic fibers (RAF) have been modified with ethanolamine to provide new chelating fibers and prepared polyacrylonitrile‐monoethanolamine (PAN‐MEA). PAN‐MEA fiber was prepared by conversion nitrile groups into hydroxyle groups using ethanolamine solution with different concentration under refluxing at different temperatures and different times.

The fiber structure has been investigated by different experimental techniques of characterization such as Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and the physical and mechanical properties has also been investigated in this study. The PAN‐MEA was examined as chelating material in a series of batch adsorption experiments for removal Cu (II), Pb (II) and Ni (II) ions. The ion adsorption of PAN‐MEA was determined with the atomic adsorption method. PAN‐MEA show adsorption metal ions more than usual fiber because of the modification.
A longitudinal program for biomarker development in Parkinson's disease: A feasibility study
Authors: Ravina Bernard , Tanner Caroline , DiEuliis Diane , Eberly Shirley , Flagg Emily , Galpern Wendy R. , Fahn Stanley , Goetz Christopher G. , Grate Stephen , Kurlan Roger , Lang Anthony E. , Marek Kenneth , Kieburtz Karl , Oakes David , Elliott Robin , Shoulson Ira
Published: August 2009

Long‐term follow up is necessary to understand the natural history of treated Parkinson's disease (PD). The Longitudinal and Biomarker Study in PD (LABS‐PD) is an observational study designed to prospectively measure the evolution of motor and non‐motor features of PD and sample promising biomarkers from early to late stage illness. LABS‐PD is organized on the premise that cohorts from completed clinical trials can be re‐recruited for long‐term follow up. LABS‐PD will eventually contain multiple cohorts, but to test the feasibility of the strategy, we examined enrollment and biomarker sampling in the initial cohorts. The first PD cohort (PostCEPT) comes from the de novo clinical trial of a mixed lineage kinase inhibitor (PRECEPT). We assessed the recruitment from PRECEPT to PostCEPT, the ability to link data from the two studies, and sample collection for a variety of biomarkers. A total of 537 of 709 eligible PRECEPT subjects (76%) enrolled in PostCEPT; 509 (95%) had repeat dopamine transporter imaging. PRECEPT clinical and imaging data were successfully linked to PostCEPT, to provide 3 to 4 year follow‐up. A biomarker sub‐study enrolled over 100 PD cases from PostCEPT and 100 controls to measure olfaction and blood markers of gene expression, α‐synuclein, and proteomic profiles. We were also successful in linking clinical and biomarker data to DNA samples that have been collected in the publicly accessible Coriell repository. The PostCEPT cohort and associated studies strongly support the feasibility of the LABS‐PD approach of retaining and repurposing clinical trial cohorts to collect longitudinal clinical and biomarker data. © 2009 Movement Disorder Society
Restless legs syndrome in Parkinson's disease
Authors: Peralta Cecilia M. , Frauscher Birgit , Seppi Klaus , Wolf Elisabeth , Wenning Gregor K. , Högl Birgit , Poewe Werner
Published: August 2009

We aimed to investigate the prevalence of restless legs syndrome (RLS) according to essential diagnostic criteria, and to explore potential associations with clinical features, especially motor fluctuations, in a cohort of 113 patients with idiopathic Parkinson's disease (PD). Twenty‐eight (24%) fulfilled essential diagnostic criteria for RLS. They were younger (63.1 ± 8.6 vs. 68.8 ± 9.0 years; P = 0.004), had an earlier onset of PD (54.1 ± 9.5 vs. 59.2 ± 10.3 years; P = 0.018), and received lower levodopa equivalent doses (578.4 ± 382.2 vs. 779.1 ± 459.6 mg/day; P = 0.04) than patients with PD who scored negative for RLS. In 23 patients (82%), RLS symptom onset was after PD onset (mean interval, 4.5 ± 3.7 years). The majority (n = 17, 61%) who scored positive for RLS reported that the urge to move the legs and unpleasant sensations were associated with wearing off, raising the possibility of RLS mimics in fluctuating patients with PD. © 2009 Movement Disorder Society
Major nutritional issues in the management of Parkinson's disease
Authors: Barichella Michela , Cereda Emanuele , Pezzoli Gianni
Published: August 2009

As with other neurodegenerative diseases, neurologic and nutritional elements may interact affecting each other in Parkinson's disease (PD). However, the long‐term effects of such interactions on prognosis and outcome have not been given much attention and are poorly addressed by current research. Factors contributing to the clinical conditions of patients with PD are not only the basic features of PD, progression of disease, and the therapeutic approach but also fiber and nutrient intakes (in terms of both energy and protein content), fluid and micronutrient balance, and pharmaconutrient interactions (protein and levodopa). During the course of PD nutritional requirements frequently change. Accordingly, both body weight gain and loss may occur and, despite controversy, it seems that both changes in energy expenditure and food intake contribute. Nonmotor symptoms play a significant role and dysphagia may be responsible for the impairment of nutritional status and fluid balance. Constipation, gastroparesis, and gastro‐oesophageal reflux significantly affect quality of life. Finally, any micronutrient deficiencies should be taken into account. Nutritional assessments should be performed routinely. Optimization of pharmacologic treatment for both motor and nonmotor symptoms is essential, but nutritional interventions and counseling could and should also be planned with regard to nutritional balance designed to prevent weight loss or gain; optimization of levodopa pharmacokinetics and avoidance of interaction with proteins; improvement in gastrointestinal dysfunction (e.g., dysphagia and constipation); prevention and treatment of nutritional deficiencies (micronutrients or vitamins). A balanced Mediterranean‐like dietary regimen should be recommended before the introduction of levodopa; afterward, patients with advanced disease may benefit considerably from protein redistribution and low‐protein regimens. © 2009 Movement Disorder Society
Existence and properties of solutions for neural field equations
Authors: Potthast Roland , Beim Graben Peter
Published: August 2009

The first goal of this work is to study the solvability of the neural
field equation (known as ‘Amari equation’)

which is an integro‐differential equation in m+ 1 dimensions. In particular, we show the existence of global solutions for smooth activation functions f with values in [0, 1] and L1 kernels w via the Banach fixpoint theorem. We note that this setting is much more general than in most related studies, e.g. Ermentrout and McLeod (Proceedings of the Royal Society of Edinburgh 1993; 123A:461–478).

For a Heaviside‐type activation function f, we show that the approach above fails. However, with slightly more regularity on the kernel function w (we use Hölder continuity with respect to the argument x) we can employ compactness arguments, integral equation techniques and the results for smooth nonlinearity functions to obtain a global existence result in a weaker space.

Finally, general estimates on the speed and durability of waves are derived. We show that compactly supported waves with directed kernels (i.e. w(x, y)⩽0 for x⩽y ) decay exponentially after a finite time and that the field has a well‐defined finite speed. Copyright © 2009 John Wiley & Sons, Ltd.
Zakharov–Shabat system and hyperbolic pseudoanalytic function theory
Authors: Kravchenko Viktor G. , Kravchenko Vladislav V. , Tremblay Sébastien
Published: August 2009

In J. Phys. A: Math. Theor. 2008; 41:65205 a hyperbolic analogue of pseudoanalytic function theory was developed. In the present contribution we show that one of the central objects of the inverse problem method, the Zakharov–Shabat system is closely related to a hyperbolic Vekua equation for which among other results a generating sequence and hence a complete system of formal powers can be constructed explicitly. Copyright © 2009 John Wiley & Sons, Ltd.
Reconstruction of potentials in quantum dots and other small symmetric structures
Authors: Khmelnytskaya Kira V. , Torchynska Tetyana V.
Published: August 2009

A method for reconstructing symmetric potentials of Schrödinger
operators from a finite set of eigenvalues is presented. The method combines the approach developed by Rundell and Coworkers (SIAM Monographs on Mathematical Modeling and Computation. SIAM: Philadelphia, PA; (1997)) for solving inverse Sturm–Liouville problems with a recent result by Kravchenko (Complex Variables and Elliptic Equations 2008; 53(8):775–789) giving accurate solutions of direct problems.

Our construction allows one to recover the potential in situations of great importance in studying nanostructures including quantum dots when only a very limited number of eigenvalues (3–4) obtained experimentally is available. Copyright © 2009 John Wiley & Sons, Ltd.
On generalized Helmholtz type equations in concentric annular domains in ℝ3
Authors: Constales Denis , Grob Dennis , Kraußhar Rolf Sören
Published: August 2009

In this paper we consider inhomogeneous generalized Helmholtz type equations (Δ+λ2)u=f in the annulus of an arbitrary ball in ℝ3 with given boundary conditions, where we assume that λ is an arbitrary complex number. Applying the hypercomplex operator calculus, one can express the solutions in terms of quaternionic integral operators. The quantitative entities to be determined in order to calculate these integral operators in practice are the Cauchy kernel and the Bergman kernel for eigensolutions to the Dirac operator in ℝ3. In contrast to the Cauchy kernel, which is universal for all domains in ℝ3, the Bergman kernel depends on the domain. In this paper, we give an explicit formula for the Bergman kernel of the annulus of a ball in ℝ3 with arbitrary radii 0<R1<R2<+∞ in terms of explicit special functions. With the knowledge of the Bergman kernel, the appearing integral operators can be evaluated fully analytically and thus provide us with explicit formulas for the solutions. Copyright © 2009 John Wiley & Sons, Ltd.
Linearization of the Riemann problem for a triangular system of conservation laws and delta shock wave formation process
Authors: Mitrovic D. , Bojkovic V. , Danilov V. G.
Published: August 2009

Using the weak asymptotic method, we approximate a triangular system of conservation laws arising from the so‐called generalized pressureless gas dynamics by a diagonal linear system. Then, we apply the usual method of characteristics to find approximate solution to the original system. As a consequence, we shall see how the delta shock wave naturally arises along the characteristics.

Also, we propose a procedure that could be applied to more general systems of conservation laws. Copyright © 2009 John Wiley & Sons, Ltd.
Stationary solutions to the Falk system on shape memory alloys
Authors: Suzuki Takashi , Tasaki Souhei
Published: August 2009

We study the Falk model system describing martensitic phase transitions in shape memory alloys. Its physically closed stationary state is formulated as a nonlinear eigenvalue problem with a non‐local term. Then, some results on existence, stability, and bifurcation of the solution are proven. In particular, we prove the existence of dynamically stable nontrivial stationary solutions. Copyright © 2009 John Wiley & Sons, Ltd.
Robust structural damage identification based on multi‐objective optimization
Authors: Jung Sungmoon , Ok Seung‐Yong , Song Junho
Published: August 2009

Inverse analysis for structural damage identification often involves an optimization process that minimizes the discrepancies between the computed responses and the measured responses. Conventional single‐objective optimization approach defines the objective function by combining multiple error terms into a single one, which leads to a weaker constraint in solving the identification problem. A multi‐objective approach is proposed, which minimizes multiple error terms simultaneously. Its non‐domination‐based convergence provides a stronger constraint that enables robust identification of damages with lower false‐negative detection rate. Another merit of the proposed approach is quantified confidence in damage detection through processing Pareto‐optimal solutions. Numerical examples that simulate static testing are provided to compare the proposed approach with conventional formulation based on single‐objective optimization. Copyright © 2009 John Wiley & Sons, Ltd.
Applicability of electrical resistivity tomography monitoring to coarse blocky and ice‐rich permafrost landforms
Authors: Hilbich C. , Marescot L. , Hauck C. , Loke M. H. , Mäusbacher R.
Published: August 2009

The inversion and interpretation of electrical resistivity tomography (ERT) data from coarse blocky and ice‐rich permafrost sites are challenging due to strong resistivity contrasts and high contact resistances. To assess temporal changes during ERT monitoring (ERTM), corresponding inversion artefacts have to be separated from true subsurface changes. Appraisal techniques serve to analyse an ERTM data set from a rockglacier, including synthetic modelling, the depth of investigation index technique and the so‐called resolution matrix approach. The application of these methods led step by step to the identification of unreliable model regions and thus to the improvement in interpretation of temporal resistivity changes. An important result is that resistivity values of model regions with strong resistivity contrasts and highly resistive features are generally of critical reliability, and resistivity changes within or below the ice core of a rockglacier should therefore not be interpreted as a permafrost signal. Conversely, long‐term degradation phenomena in terms of warming of massive ground ice at the permafrost table are detectable by ERTM. Copyright © 2009 John Wiley & Sons, Ltd.
Past permafrost on the Mid‐Atlantic Coastal Plain, eastern United States
Authors: French Hugh , Demitroff Mark , Newell Wayne L.
Published: August 2009

Sand‐wedge casts, soil wedges and other non‐diastrophic, post‐depositional sedimentary structures suggest that Late‐Pleistocene permafrost and deep seasonal frost on the Mid‐Atlantic Coastal Plain extended at least as far south as southern Delaware, the Eastern Shore and southern Maryland. Heterogeneous cold‐climate slope deposits mantle lower valley‐side slopes in central Maryland. A widespread pre‐existing fragipan is congruent with the inferred palaeo‐permafrost table. The high bulk density of the fragipan was probably enhanced by either thaw consolidation when icy permafrost degraded at the active layer‐permafrost interface or by liquefaction and compaction when deep seasonal frost thawed. Copyright © 2009 John Wiley & Sons, Ltd.
Genesis of active sand‐filled polygons in lower and central Beacon Valley, Antarctica
Authors: Bockheim James G. , Kurz Mark D. , Soule S. Adam , Burke Andrea
Published: August 2009

Nonsorted polygons with sand‐filled wedges were investigated in Beacon Valley, Antarctica (77.82°S, 160.67°E) using field observations coupled with 2‐m resolution aerial photography. A gasoline‐powered concrete breaker was employed to expose the sediments of four polygon centres and six wedges from geomorphic surfaces containing tills of two different ages. The excavated polygons ranged from 9 to 16 m in diameter; the sand‐filled wedges ranged from 0.2 to 2.5 m in width. The top of ice‐bonded permafrost ranged from 12 to 62 cm in depth in the polygon centres and from 64 to >90 cm in wedges. One active thermal‐contraction fissure generally was apparent at the surface, but excavations revealed numerous inactive fissures. The wedges contain sand laminations averaging 3 mm in width when viewed in cross‐section. Although most of the polygons were of the sand‐wedge type, some contained ice veins up to 1 cm in width and could be classed as composite wedges. Three stages of polygon development were observed, including well‐developed polygons on Taylor II surfaces (ca. 117 ka), moderately developed polygons on Taylor III surfaces (ca. 200 ka) and poorly expressed polygons on Taylor IVa and older (ca. >1.1 Ma) surfaces. This retrogressive development may be due to sublimation of ice‐bonded permafrost following thermal cracking. With the drop in ice content, the thermal coefficient of expansion of the permafrost may be lowered, which would result in a reduction in tensile stresses. Copyright © 2009 John Wiley & Sons, Ltd.
Tissue is alive: New technologies are needed to address the problems of protein biomarker pre‐analytical variability
Authors: Espina Virginia , Mueller Claudius , Edmiston Kirsten , Sciro Manuela , Petricoin Emanuel F. , Liotta Lance A.
Published: August 2009

Instability of tissue protein biomarkers is a critical issue for molecular profiling. Pre‐analytical variables during tissue procurement, such as time delays during which the tissue remains stored at room temperature, can cause significant variability and bias in downstream molecular analysis. Living tissue, ex vivo, goes through a defined stage of reactive changes that begin with oxidative, hypoxic and metabolic stress, and culminate in apoptosis. Depending on the delay time ex vivo, and reactive stage, protein biomarkers, such as signal pathway phosphoproteins will be elevated or suppressed in a manner which does not represent the biomarker levels at the time of excision. Proteomic data documenting reactive tissue protein changes post collection indicate the need to recognize and address tissue stability, preservation of post‐translational modifications, and preservation of morphologic features for molecular analysis. Based on the analysis of phosphoproteins, one of the most labile tissue protein biomarkers, we set forth tissue procurement guidelines for clinical research. We propose technical solutions for (i) assessing the state of protein analyte preservation and specimen quality via identification of a panel of natural proteins (surrogate stability markers), and (ii) using multi‐purpose fixative solution designed to stabilize, preserve and maintain proteins, nucleic acids, and tissue architecture.
Proteomic approaches for investigation of therapy resistance in cancer
Authors: Lage Hermann
Published: August 2009

Resistance to anticancer therapy is a major obstacle for successful management of patients in oncology. Although in the past, various biological mechanisms involved in therapy resistance, in particular multidrug resistance, have been identified, cancer patients did not really benefit. The mechanisms include the enhanced activity of drug extrusion pumps, modulation of cellular death pathways, alteration and repair of target molecules and various other mechanisms. Together they build a complex network mediating an individual therapy‐resistant phenotype. The improved description of this multifactorial network should be useful for prediction of treatment response and would allow to design an individual‐tailored therapy regiment. Proteome analyzing technologies appear as powerful tools for identifying new factors and protein expression profiles associated with anticancer therapy resistance. In the last years, the application of proteomic techniques identified multiple new factors or protein expression signatures in drug‐resistant cell models and cancerous tissues. However, the functional role and the clinical impact of these findings are not yet clarified. So far, none of the proteomic data were useful for the development of improved diagnostic tests, for prediction of individual therapy response or for development of updated chemosensitizers. Here, the previous therapy resistance‐related proteome data and future perspectives will be discussed.
Proteomics reveals acute pro‐inflammatory and protective responses in rat Kupffer cells and hepatocytes after chemical initiation of liver cancer and after LPS and IL‐6
Authors: Lorenz Olga , Parzefall Wolfram , Kainzbauer Eveline , Wimmer Helge , Grasl‐Kraupp Bettina , Gerner Christopher , Schulte‐Hermann Rolf
Published: August 2009

Inflammation is a key event in the development of liver cancer. We studied early inflammatory responses of Kupffer cells (KCs) and hepatocyte (HC) after cancer initiation. The chemical carcinogen N‐nitrosomorpholine (NNM) was used in a rat model. We applied a comprehensive analytical strategy including metabolic labeling, 2‐D PAGE, LC‐MS/MS‐based spot identification and shotgun proteomics and thus determined the rates of synthesis of individual proteins, compared whole tissue with isolated constituent cells and performed in vivo to in vitro comparisons of NNM effects. NNM increased synthesis of overall and 138 individual proteins identified in HC and/or KC, indicating reprogramming of metabolism favoring protection, repair and replacement of cell constituents in HC and KC. Secretome analysis by 2‐D PAGE and shotgun proteomics of HC revealed the induction of acute phase proteins, in case of KC of proteases, cytokines and chemokines, indicating inflammatory effects. All responses were induced rapidly, independently of signals from other cells, and closely mimicked the pro‐inflammatory and protective effects of inflammation modulators LPS in KC and IL‐6 in HC. In conclusion, the carcinogen NNM exerts pro‐inflammatory effects in the liver, partially by direct activation of KC. The acute inflammation and its protective component will enhance formation, survival and proliferation of initiated cells and may therefore act synergistically with the genotoxic action of the carcinogen.
PTPIP51 mRNA and protein expression in tissue microarrays and promoter methylation of benign prostate hyperplasia and prostate carcinoma
Authors: Koch Philipp , Petri Meike , Paradowska Agnieszka , Stenzinger Albrecht , Sturm Klaus , Steger Klaus , Wimmer Monika
Published: August 2009

BACKGROUND

Protein tyrosine phosphatase interacting protein 51 (PTPIP51) shows a tissue‐specific expression pattern and is associated with cellular differentiation and apoptosis in several mammalian tissues. Overexpression of the full‐length protein enhances apoptosis. It is also expressed in various carcinomas. In this study the expression of PTPIP51 and its in vitro interaction partners was investigated in human benign prostate hyperplasia (BPH) and in prostate carcinoma (PCa).

METHODS

Tissue microarrays of human BPH and PCa were analyzed by immunohistochemistry. For polymerase chain reaction (PCR), cryo samples of BPH and PCa were used. Bisulfite DNA treatment, followed by sequencing of PCR products was performed in order to analyze CpGs methylation within the promoter region of the PTPIP51 gene.

RESULTS

PTPIP51 mRNA and protein expression was detected in prostatic epithelia of BPH and in tumor cells of PCa, respectively, and within smooth muscle cells of the stromal compartment. A stronger expression was present in nerve fibers, particularly in PCa, in immune cells and in smooth muscle and endothelial cells of vessels of BPH and PCa. On mRNA levels, a slightly elevated expression of PTPIP51 was observed in the PCa group as tested by real‐time quantitative PCR analyses. Methylation experiments revealed that at least 70% of methylated CpGs in the CpG island of the PTPIP51 gene promoter region were identified in BPH samples. In contrast, a loss of methylation has been found in the PCa group.

CONCLUSION

The promoter methylation status of PTPIP51 seems to influence the expression of PTPIP51, which was seen as elevated in the PCa. Prostate 69: 1751–1762, 2009. © 2009 Wiley‐Liss, Inc.
The relationship of neuroendocrine carcinomas to anti‐tumor therapies in TRAMP mice
Authors: Tang Yao , Wang Linbo , Goloubeva Olga , Khan Mohammad Afnan , Lee DongIk , Hussain Arif
Published: August 2009

BACKGROUND

Neuroendocrine differentiation and neuroendocrine carcinoma (NEC) have been linked to androgen deprivation in prostate cancers. No previous study has directly connected neuroendocrine phenotypes to chemotherapy. The pathogenesis of prostatic NEC has not yet been determined.

METHODS

Using the transgenic adenocarcinoma of mouse prostate (TRAMP) model, we studied tumor progression after hormone ablation (castration) and/or chemotherapy (docetaxel), and analyzed the incidence of NEC as a function of the anti‐tumor therapies. Non‐treated mice were used as controls. Protein expressions in tumor tissues were analyzed by Western blots and immunohistochemistry.

RESULTS

Although all animals developed prostate cancer, no NEC was found in control mice. However, over 30% of the mice that received an anti‐tumor therapy developed NEC. A similar incidence of NEC was found in the castration‐only and docetaxel‐only treatment groups, while a higher incidence was observed in the combined treatment (castration and docetaxel) group. The NEC‐bearing mice had smaller tumors in their prostates and lived longer than mice with adenocarcinoma (ADC‐only). However, NEC tumors had a higher proliferative index and greater potential for metastasis and drug‐resistance, as evidenced by significantly higher expression levels of PCNA, S100A4, and Pgp, but lower levels of E‐cadherin. SV40 T‐antigen was highly expressed in both NEC and ADC tumors.

CONCLUSIONS

Stress induced by anti‐cancer treatments may play a role in NEC development. Although NEC and ADC differ in their expressions of many proteins, a high level of SV40 T‐antigen in both tumor types suggest a common progenitor. Prostate 69: 1763–1773, 2009. © 2009 Wiley‐Liss, Inc.
Preliminary studies on noncovalent hyperbranched polymers based on PNA and DNA building blocks
Authors: Moccia Maria , Musumeci Domenica , Roviello Giovanni N. , Fusco Sabato , Valente Margherita , Bucci Enrico M. , Sapio Roberto , Pedone Carlo , Netti Paolo A.
Published: August 2009

In this work, we report thermodynamic, kinetic, and microrheological studies relative to the formation of PNA‐ and PNA/DNA‐based noncovalent polymeric systems, useful tools for biotechnological and bioengineering applications. We realized two kinds of systems: a PNA‐based system formed by a self‐assembling PNA tridendron, and a PNA/DNA hybrid system formed by a PNA tridendron and a DNA linker. The formation of a three‐dimensional polymeric network, by means of specific Watson–Crick base pairing, was investigated by a detailed UV and CD spectroscopic study. Preliminary microrheology experiments were performed on both systems to evaluate their viscoelastic properties which resulted in agreement with the formation of soluble hyperbranched polymers that could be useful for drug/gene delivery, as well as for encapsulating organic pollutants of different shapes and sizes in environmental applications. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Membrane association and selectivity of the antimicrobial peptide NK‐2: a molecular dynamics simulation study
Authors: Pimthon Jutarat , Willumeit Regine , Lendlein Andreas , Hofmann Dieter
Published: August 2009

In an effort to better understand the initial mechanism of selectivity and membrane association of the synthetic antimicrobial peptide NK‐2, we have applied molecular dynamics simulation techniques to elucidate the interaction of the peptide with the membrane interfaces. A homogeneous dipalmitoylphosphatidylglycerol (DPPG) and a homogeneous dipalmitoylphosphatidylethanolamine (DPPE) bilayers were taken as model systems for the cytoplasmic bacterial and human erythrocyte membranes, respectively. The results of our simulations on DPPG and DPPE model membranes in the gel phase show that the binding of the peptide, which is considerably stronger for the negatively charged DPPG lipid bilayer than for the zwitterionic DPPE, is mostly governed by electrostatic interactions between negatively charged residues in the membrane and positively charged residues in the peptide. In addition, a characteristic distribution of positively charged residues along the helix facilitates a peptide orientation parallel to the membrane interface. Once the peptides reside close to the membrane surface of DPPG with the more hydrophobic side chains embedded into the membrane interface, the peptide initially disturbs the respective bilayer integrity by a decrease of the order parameter of lipid acyl chain close to the head group region, and by a slightly decrease in bilayer thickness. We found that the peptide retains a high content of helical structure on the zwitterionic membrane‐water interface, while the loss of α‐helicity is observed within a peptide adsorbed onto negatively charged lipid membranes. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Design of a bioactive cell‐penetrating peptide: when a transduction domain does more than transduce
Authors: Ward Brian , Seal Brandon L. , Brophy Colleen M. , Panitch Alyssa
Published: August 2009

The discovery of cell‐penetrating peptides (CPPs) has facilitated delivery of peptides into cells to affect cellular behavior. Previously, we were successful at developing a phosphopeptide mimetic of the small heat shock‐like protein HSP20 . Building on this success we developed a cell‐permeant peptide inhibitor of mitogen‐activated protein kinase‐activated protein kinase 2 (MK2). It is well documented that inhibition of MK2 may be beneficial for a myriad of human diseases including those involving inflammation and fibrosis. During the optimization of the activity and specificity of the MK2 inhibitor (MK2i) we closely examined the effect of cell‐penetrating peptide identity. Surprisingly, the identity of the CPP dictated kinase specificity and functional activity to an extent that rivaled that of the therapeutic peptide. The results reported herein have wide implications for delivering therapeutics with CPPs and indicate that judicious choice of CPP is crucial to the ultimate therapeutic success. Published in 2009 by John Wiley & Sons, Ltd.
Highly textured zinc oxide films by room temperature ion beam assisted deposition
Authors: Köhl D. , Luysberg M. , Wuttig M.
Published: August 2009

A new ion beam assisted sputter deposition technique has been developed which facilitates room temperature fabrication of thin ZnO films with exceptional structural order. The well‐defined texture of these films is comparable to films deposited at elevated temperatures of typically 200–300 °C in standard sputter processes. Structural investigations reveal that the applied Xe+ ion bombardment mainly affects the nucleation of ZnO crystallites. The high structural order of the nucleation layer is maintained in subsequent stages of film growth. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of soil moisture on the development of a Sahelian mesoscale convective system: a case‐study from the AMMA Special Observing Period
Authors: Taylor Christopher M. , Harris Phil P. , Parker Douglas J.
Published: August 2009

Interactions between the land and atmosphere play an important role in the precipitation of the Sahel. The African Monsoon Multidisciplinary Analysis Special Observing Period provided observations with which to illuminate potential feedback mechanisms. This case‐study highlights a major storm which developed over northern Mali in an area where a research aircraft was surveying the atmospheric response to soil moisture features. Soil moisture variability is characterized using satellite land‐surface temperature data whilst cloud images illustrate the evolution of the storm and its relationship to the surface.

Measurements in the planetary boundary layer (PBL) indicate mesoscale variations in pre‐storm humidity and temperature consistent with high evaporation from wet soils. The storm developed above a dry surface within a wetter region with cells first appearing along a wet–dry soil boundary. This suggests that the storm was triggered in association with low‐level convergence driven by the soil moisture pattern. A gravity wave propagating away from a remote mature storm also appears to have played an important role in the initiation, though only in the region of the soil moisture contrast did deep convection become established. Once organised into a Mesoscale Convective System, convection developed over wet areas as well as dry, and indeed at this stage, convection became more intense over wetter soils. This behaviour is consistent with the large gradients in PBL humidity. The study illustrates the complexity of soil moisture–convection feedback loops and highlights the mechanisms which may operate at different stages of a storm's life cycle. Copyright © 2009 Royal Meteorological Society
Multiple minima hypersurfaces studies of aluminosilicate hydration
Authors: Pérez‐Badell Yoana , Montero Luis A.
Published: August 2009

Hydrothermal zeolite synthesis is a complex process that is difficult to analyze experimentally. In this work, the role of water as solvent on the formation of aluminate and aluminosilicate clusters is described by quantum chemical calculations. The multiple minima hypersurfaces approach was used. It combines quantum chemical Hamiltonians for the calculation of the internal energy with statistical modeling and formulae for the calculation of thermodynamic functions of association. The structures of most probable hydration clusters are proposed and some of their association properties are calculated. Ab initio and semiempirical calculations of the structures and relevant reactions of aluminate and aluminosilicate fragments were reported. The results could be employed for an interpretation of the aluminosilicate synthesis. Calculations demonstrate the importance of considering other than the deepest minimum structures, giving a significant role to consider entropy of association. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Directed mechanical motion in nonequilibrium nanosystems: Occurrence conditions and kinematic controllability
Authors: Dekhtyar Marina L. , Korochkova Taisiya Ye. , Rozenbaum Viktor M.
Published: August 2009

The directed mechanical motion of nanoscale objects along a phase boundary can result from strongly nonequilibrium processes, which transfer the energy of various external sources to the system. This effect is particularly relevant in Brownian (molecular or biological) motors known for their high efficiency of chemical‐to‐kinetic energy conversion. Here, we formulate the necessary conditions for nanoparticle surface‐parallel motion to occur under the action of external nonequilibrium fluctuations of various nature; the ways to provide such conditions are also considered. As shown, the magnitude and sign of the average directed velocity are dictated by the competition between the spatial and temporal asymmetry of the potential energy. The theoretical models are exemplified by high‐efficiency Brownian nanoengines, molecular pumps, dipole rotators, and photo‐induced molecular motors. The latter serve to illustrate the kinematic controllability of motors by varying their molecular structure and photoexcitation parameters. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Accurate environmental bioindication in floodplains in spite of an extreme flood event
Authors: Follner Klaus , Hofacker Anke , Glaeser Judith , Dziock Frank , Gerisch Michael , Foeckler Francis , Ilg Christiane , Schanowski Arno , Scholz Mathias , Henle Klaus
Published: August 2009

The ecological reaction of species on environmental factors can differ both, temporally and geographically. Therefore, bioindicator systems must be shown to remain accurate at different places and points of time. Extreme events pose challenges for testing this robustness, which has not yet been explored systematically. The unique opportunity of the extreme flooding of the river Elbe in August 2002 was used for such a test. The bioindicator system for mean groundwater depth during the vegetation period and annual duration of inundation in floodplains studied here was developed with data collected in 1999. Data from 2003 were used to analyse the dependence of the bioindication results on the humidity of the study plots and taxonomic group (plants, molluscs and carabid beetles). For the duration of inundation, the accuracy of bioindication in 2003 was similar to that in 1999, except for the medium‐humid and dry plots using molluscs as indicators. For groundwater depth, the accuracy of bioindication in 2003 was similar to that of the reference year except in the dry plots with significantly lower accuracy for all species groups. With a few exceptions, the bioindicator system is shown to be robust and to remain accurate in spite of an extreme flood event. In conclusion, the relevance of extreme events for the robustness of bioindicator systems differs between the indicated parameters and taxonomic groups. The results stress the need to take into account the limits of the working range and the occurrence of extreme events, when testing and applying bioindicator systems. Copyright © 2009 John Wiley & Sons, Ltd.
Error analysis and regression mode of the V‐grooved sample in the atomic force microscope simulation measurement mode by the molecular mechanics
Authors: Lin Zone‐Ching , Huang Jen‐Ching , Yeh Chun‐Hui
Published: August 2009

Based on the molecular mechanics, this study uses the two‐body potential energy function to construct a trapezoidal cantilever nano‐scale simulation measurement model of contact mode atomic force microscopy (AFM) under the constant force mode to simulate the measurement the nano‐scale V‐grooved standard sample. We investigate the error of offset distance of the cross‐section profile when using the probes with different trapezoidal cantilever probe tip radii (9.5, 8.5, and 7.5 Å) to scan the peak of the V‐grooved standard sample being reduced to one‐tenth (1/10) of its size, and use the offset error to inversely find out the regression equation. We analyze how the tip apex as well as the profile of the tip edge oblique angle and the oblique edge angle affects the offset distance. Furthermore, a probe with a larger radius of 9.5 nm is used to simulate and measure the offset error of scan curve, and acquire the regression equation. By the conversion proportion coefficient of size (ω), and revising the size‐reduced regression equation during the small size scale, a revised regression equation of a larger size scale can be acquired. The error is then reduced, further enhancing the accuracy of the AFM scanning and measurement. SCANNING 31: 147–159, 2009. © 2009 Wiley Periodicals, Inc.
Interval estimation for the difference in paired areas under the ROC curves in the absence of a gold standard test
Authors: Hsieh Hsin‐Neng , Su Hsiu‐Yuan , Zhou Xiao‐Hua
Published: August 2009

Receiver operating characteristic (ROC) curves can be used to assess the accuracy of tests measured on ordinal or continuous scales. The most commonly used measure for the overall diagnostic accuracy of diagnostic tests is the area under the ROC curve (AUC). A gold standard (GS) test on the true disease status is required to estimate the AUC. However, a GS test may sometimes be too expensive or infeasible. Therefore, in many medical research studies, the true disease status of the subjects may remain unknown. Under the normality assumption on test results from each disease group of subjects, using the expectation‐maximization (EM) algorithm in conjunction with a bootstrap method, we propose a maximum likelihood‐based procedure for the construction of confidence intervals for the difference in paired AUCs in the absence of a GS test. Simulation results show that the proposed interval estimation procedure yields satisfactory coverage probabilities and interval lengths. The proposed method is illustrated with two examples. Copyright © 2009 John Wiley & Sons, Ltd.
A semi‐parametric threshold regression analysis of sexually transmitted infections in adolescent women
Authors: Yu Zhangsheng , Tu Wanzhu , Lee Mei‐Ling Ting
Published: August 2009

Time‐to‐event analysis of sexually transmitted infection data is often complicated by the existence of nonproportional hazards and nonlinear independent variable effects. Methods without the proportional hazards assumption, such as threshold regression models, have been successfully used in many applications. This paper seeks to extend the existing threshold regression models to accommodate the nonlinear independent variable effects. Specifically, we incorporated penalized and regression splines to the threshold regression models for added modeling flexibility. Cross validation methods were used for the selection of the number of knots and for the determination of smoothing parameters. Variance estimates were proposed for inference purposes. Simulation results showed that the proposed methods were able to achieve nonparametric function and parametric coefficient estimates that are close to their true values. Simulation also demonstrated satisfactory performance of variance estimates. Using the proposed methods, we analyzed time from sexual debut to the first infection withChlamydia trachomatisinfection in a group of young women. Analysis shows that the lifetime number of sexual partners has a nonlinear effect on the risk ofC. trachomatisinfection and the infection risks were differential by ethnicity and age of sexual debut. Copyright © 2009 John Wiley & Sons, Ltd.
A conditional sequential sampling procedure for drug safety surveillance
Authors: Li Lingling
Published: August 2009

We propose a practical group sequential method, a conditional sequential sampling procedure, to test if a drug of interest (D) leads to an elevated risk for an adverse event E compared with a comparison drug C. The method is designed for prospective drug safety surveillance studies, in which, for each considered drug, a summary table with the exposed person‐times and the associated numbers of adverse events summed by strata defined by several potential confounders, is collected and updated periodically using the health plans' administrative claims data. This new approach can be applied to test for elevated relative risk whenever the data are updated. Our approach adjusts for multiple testing to preserve the overall type I error with any specified α‐spending function. Furthermore, it automatically adjusts for temporal trend and population heterogeneity across strata by conditioning on the numbers of adverse events within each stratum during each time period. Therefore, this approach is very flexible and applies to a wide class of settings. We conduct a simulation study to evaluate its performance under various scenarios. The approach is also applied to an example to examine if Rofecoxib leads to an increased relative risk for acute myocardial infraction (AMI) compared with its two counterparts Diclofenac and Naproxen, respectively. We end with discussions. Copyright © 2009 John Wiley & Sons, Ltd.
Bayesian analysis of a matched case–control study with expert prior information on both the misclassification of exposure and the exposure–disease association
Authors: Liu Juxin , Gustafson Paul , Cherry Nicola , Burstyn Igor
Published: August 2009

We propose a Bayesian adjustment for the misclassification of a binary exposure variable in a matched case–control study. The method admits a priori knowledge about both the misclassification parameters and the exposure–disease association. The standard Dirichlet prior distribution for a multinomial model is extended to allow separation of prior assertions about the exposure–disease association from assertions about other parameters. The method is applied to a study of occupational risk factors for new‐onset adult asthma. Copyright © 2009 John Wiley & Sons, Ltd.