bluuebunny/crossref_metadata_2025 huggingface dataset:
p16INK4a overexpression predicts translational active human papillomavirus infection in tonsillar cancer
Authors: Hoffmann Markus , Ihloff Anna Sophie , Görögh Tibor , Weise Jan B. , Fazel Asita , Krams Matthias , Rittgen Werner , Schwarz Elisabeth , Kahn Tomas
Published: January 2010

The causal role of human papillomaviruses (HPV) in squamous cell carcinogenesis of tonsillar cancers (TSCC) depends on the activity of the viral oncoproteins E6 and E7, leading to inactivation of the cellular tumor suppressor p53 and the retinoblastoma gene product pRb. Because of the negative feedback mechanisms, the pRb inactivation causes an increase of the inhibitor of the cyclin‐dependent kinases p16INK4a. In 39 TSCC specimens, genotyping based on the amplification of HPV DNA was carried out using PCR by applying HPV type‐specific oligonucleotides. Subsequently, amplicons were hybridised with fluorescence‐labeled complementary probes using the Southern blot technology. For HPV E6/E7 mRNA expression, Northern hybridization and RT‐PCR were performed, and for p16INK4a detection, immunohistochemistry was performed. With 21/39 (53%) HPV‐positives, the detection rate is within the range that can be expected in TSCC. The E6/E7 oncogene mRNA was detectable in 11 cases, 10 of which showed positive signals after p16INK4a staining. Albeit the small study group was investigated, the correlation of the HPV DNA status with the p16INK4a expression was of statistical significance (p = 0.02). Kaplan‐Meier estimations revealed better survival outcome for patients with HPV‐positive tumors with detectable E6/E7 mRNA and p16INK4a overexpression (p = 0.02, median observation time 29 months). As mRNA expression tests are not routinely available in many clinical diagnostic laboratories, and based on the high correlation of p16INK4a staining with HPV E6/E7 mRNA expression, in conclusion we suggest for a deeper exploration for the use of p16INK4a as a surrogate marker with the potential to impact the standard of care of HPV DNA‐positive head and neck carcinomas.
Tumors exposed to acute cyclic hypoxic stress show enhanced angiogenesis, perfusion and metastatic dissemination
Authors: Rofstad Einar K. , Gaustad Jon‐Vidar , Egeland Tormod A.M. , Mathiesen Berit , Galappathi Kanthi
Published: January 2010

Clinical studies have shown that patients with highly hypoxic primary tumors may have poor disease‐free and overall survival rates. Studies of experimental tumors have revealed that acutely hypoxic cells may be more metastatic than normoxic or chronically hypoxic cells. In the present work, causal relations between acute cyclic hypoxia and metastasis were studied by periodically exposing BALB/c nu/nu mice bearing A‐07 human melanoma xenografts to a low oxygen atmosphere. The hypoxia treatment consisted of 12 cycles of 10 min of 8% O2 in N2 followed by 10 min of air for a total of 4 hr, began on the first day after tumor cell inoculation and was given daily until the tumors reached a volume of 100 mm3. Twenty‐four hours after the last hypoxia exposure, the primary tumors were subjected to dynamic contrast‐enhanced magnetic resonance imaging for assessment of blood perfusion before being resected and processed for immunohistochemical examinations of microvascular density and expression of proangiogenic factors. Mice exposed to acute cyclic hypoxia showed increased incidence of pulmonary metastases, and the primary tumors of these mice showed increased blood perfusion, microvascular density and vascular endothelial growth factor‐A (VEGF‐A) expression; whereas, the expression of interleukin‐8, platelet‐derived endothelial cell growth factor and basic fibroblast growth factor was unchanged. The increased pulmonary metastasis was most likely a consequence of hypoxia‐induced VEGF‐A upregulation, which resulted in increased angiogenic activity and blood perfusion in the primary tumor and thus facilitated tumor cell intravasation and hematogenous transport into the general circulation.
CIITA‐driven MHC‐II positive tumor cells: Preventive vaccines and superior generators of antitumor CD4+ T lymphocytes for immunotherapy
Authors: Frangione Valeria , Mortara Lorenzo , Castellani Patrizia , De Lerma Barbaro Andrea , Accolla Roberto S.
Published: January 2010

In our study, we have investigated whether tumors of distinct histological origin can be rejected if expressing CIITA‐driven MHC class II molecules. Moreover, we assessed whether antitumor lymphocytes generated by this approach could be used as an immunotherapeutic tool for established cancers. Stable CIITA‐transfectants of C51colon adenocarcinoma, RENCA renal adenocarcinoma, WEHI‐164 sarcoma as well as TS/A mammary adenocarcinoma were generated. Tumor cells transfectants were injected in vivo, and their growth kinetics and recipient's immune response were analyzed. Tumor rejection and/or retardation of growth was found for the first 3 CIITA‐transfected tumor cell lines and confirmed for TS/A‐CIITA. Animals rejecting CIITA‐transfected tumors acquired specific immunological memory as demonstrated by resistance to challenge with parental tumors. Adoptive cell transfer experiments demonstrated that tumor immunity correlates with the efficient priming of CD4+ T helper cells and the consequent activation of CD8+ T lymphocytes. T cells from TS/A‐vaccinated mice were used in an adoptive immunotherapy model of established tumors. The results showed the cure at early stages and significantly prolonged survival at later stages of tumor progression. Importantly, CD4+ T cells were clearly superior to CD8+ T cells in antitumor protective function. Interestingly, the protective phenotype was associated to both a Th1 and Th2 polarization of the immune effectors. These results establish the general application of our tumor vaccine model and disclose the additional application of this strategy for producing better lymphocyte effectors for adoptive antitumor immunotherapy.
Hormone replacement therapy and incidence of central nervous system tumours in the Million Women Study
Authors: Benson Victoria S. , Pirie Kirstin , Green Jane , Bull Diana , Casabonne Delphine , Reeves Gillian K. , Beral Valerie ,   for the Million Women Study Collaborators
Published: January 2010

We examined the relation between the use of hormone replacement therapy (HRT) and the incidence of central nervous system (CNS) tumours in a large prospective study of 1,147,894 postmenopausal women. Women were aged 56.6 years on average at entry, and HRT use was recorded at recruitment and updated, where possible, about 3 years later. During a mean follow‐up of 5.3 years per woman, 1,266 CNS tumours were diagnosed, including 557 gliomas, 311 meningiomas and 117 acoustic neuromas. Compared with never users of HRT, the relative risks (RRs) for all incident CNS tumours, gliomas, meningiomas and acoustic neuromas in current users of HRT were 1.20 (95% CI: 1.05–1.36), 1.09 (95% CI: 0.89–1.32), 1.34 (95% CI: 1.03–1.75) and 1.58 (95% CI: 1.02–2.45), respectively, and there was no significant difference in the relative risks by tumour type (heterogeneity p = 0.2). In past users of HRT the relative risk was 1.07 (95% CI: 0.93–1.24) for all CNS tumours. Among current users of HRT, there was significant heterogeneity by the type of HRT with the users of oestrogen‐only HRT at higher risk of all CNS tumours than users of oestrogen–progestagen HRT (RR = 1.42, 95% CI: 1.21–1.67 versus RR = 0.97, 95% CI: 0.82–1.16) (heterogeneity p < 0.001). Among current users of oestrogen‐only and oestrogen–progestagen HRT, there was no significant heterogeneity by duration of use, hormonal constituent or mode of administration of HRT.
Tailoring the mechanical properties of 3D‐designed poly(glycerol sebacate) scaffolds for cartilage applications
Authors: Kemppainen Jessica M. , Hollister Scott J.
Published: January 2010

Matching tissue engineering scaffold modulus to that of native tissue is highly desirable. Effective scaffold modulus can be altered through changes in base material modulus and/or scaffold pore architecture. Because the latter may be restricted by tissue in‐growth requirements, it is advantageous to be able to alter the base material modulus of a chosen scaffold material. Here, we show that the bulk modulus of poly(glycerol sebacate) (PGS) can be changed by varying molar ratios during prepolymer synthesis and by varying curing time. We go on to show that PGS can be used to create 3D designed scaffolds via solid freeform fabrication methods with modulus values that fall within the ranges of native articular cartilage equilibrium modulus. Furthermore, using base material modulus inputs, homogenization finite element analysis can effectively predict the tangent modulus of PGS scaffold designs, which provides a significant advantage for designing new cartilage regeneration scaffolds. Lastly, we demonstrate that this relatively new biomedical material supports cartilaginous matrix production by chondrocytes in vitro. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Moisture‐cured silicone–urethanes—Candidate materials for tissue engineering: A biocompatibility study in vitro
Authors: Mrówka P. , Kozakiewicz J. , Jurkowska A. , Sienkiewicz E. , Przybylski J. , Lewandowski Z. , Przybylski J. , Lewandowska‐Szumieł M.
Published: January 2010

This study was performed to verify the response of human bone‐derived cells (HBDCs) to moisture‐cured silicone–urethanes (mcSUUs) in vitro, as the first step toward using them as scaffolds for bone tissue engineering. Good surgical handling, tissue cavity filling, stable mechanical properties, and potentially improved oxygen supply to cells after implantation justify the investigation of these nondegradable elastomers. A set of various mcSUUs were obtained by moisture‐curing NCO‐terminated prepolymers, synthesized from oligomeric siloxane diols of two different oligosiloxane chain lengths, and two different diisocyanates (MDI and IPDI), using two different NCO/OH molar ratios. Dibutyltindilaurate (DBTL) or N‐dimethylethanolamine (N‐met) served as catalysts. After 7 days of culture, cell number, viability, and alkaline phosphatase (ALP) activity were determined, and after 21 days, cell viability and collagen production were determined. Material characteristics significantly influenced the cell response. The mcSUUs prepared with DBTL (widely used in the syntheses of biomaterials) were cytotoxic. The MDI‐based mcSUUs were significantly more favored by HBDCs than the IPDI‐based ones in all performed tests. MDI‐based material with low 2/1 NCO/OH and short chain length was the best support for cells, comparable with tissue‐culture polystyrene (with ALP activity even higher). HBDCs cultured on porous scaffolds from this mcSUU produced a tissue‐like structure in culture. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
In vivo outcomes of tissue‐engineered osteochondral grafts
Authors: Bal B. Sonny , Rahaman Mohamed N. , Jayabalan Prakash , Kuroki Keiichi , Cockrell Mary K. , Yao Jian Q. , Cook James L.
Published: January 2010

Tissue‐engineered osteochondral grafts have been synthesized from a variety of materials, with some success at repairing chondral defects in animal models. We hypothesized that in tissue‐engineered osteochondral grafts synthesized by bonding mesenchymal stem cell‐loaded hydrogels to a porous material, the choice of the porous scaffold would affect graft healing to host bone, and the quality of cell restoration at the hyaline cartilage surface. Bone marrow‐derived allogeneic mesenchymal stem cells were suspended in hydrogels that were attached to cylinders of porous tantalum metal, allograft bone, or a bioactive glass. The tissue‐engineered osteochondral grafts, thus created were implanted into experimental defects in rabbit knees. Subchondral bone restoration, defect fill, bone ingrowth‐implant integration, and articular tissue quality were compared between the three subchondral materials at 6 and 12 weeks. Bioactive glass and porous tantalum were superior to bone allograft in integrating to adjacent host bone, regenerating hyaline‐like tissue at the graft surface, and expressing type II collagen in the articular cartilage. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Synthesis, in vitro hydroxyapatite forming ability, and cytocompatibility of strontium silicate powders
Authors: Zhang Meili , Zhai Wanyin , Lin Kaili , Pan Haobo , Lu William , Chang Jiang
Published: January 2010

Phase‐pure strontium silicate (SrSiO3) powders were synthesized by chemical precipitation method. In vitro bioactivity of the powders were evaluated by examining the hydroxyapatite forming ability on their surface soaking simulated body fluid for various periods. The results showed that SrSiO3 could induce hydroxy carbonate apatite formation after soaking for 7 days. Both L929 and rabbit bone marrow stromal cells (rMSCs) were used to test the in vitro cytocompatibility of SrSiO3. L929 culture experiment showed that the ionic product of SrSiO3 did not exhibit cytotoxicity except at high ion concentrations (Si 3.75 mM and Sr 0.12 mM). Moreover, at certain ion concentrations (Si 1.87–0.12 mM and Sr 0.12–3.75 × 10−3 mM), the ionic product of SrSiO3 stimulated the proliferation of rMSCs. All the results indicated that SrSiO3 might be used as a new bioactive material for bone regeneration applications. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Effect of stem preheating and precooling on residual stress formation at stem/cement interface for cemented hip implants
Authors: Madrala A. , Nuño N.
Published: January 2010

PMMA polymerization is an exothermic phenomenon during which stresses and porosity are observed. An experimental model is devised to directly measure radial forces, to be converted to radial stresses, at the stem/cement interface, and temperatures at both interfaces during cement curing. The effects of stem and bone cement initial temperatures (preheating or precooling vs. room temperature) as well as mixing method (hand vs. vacuum mixing) and cement type (Simplex P vs. Palacos R) on radial stress and temperatures are investigated. Compressive radial residual stresses at the stem/cement interface are measured for hand mixed PMMA with preheated stem, with a maximum magnitude of 1.0 MPa. No radial residual stresses are observed when the stem is initially at room temperature or precooled, suggesting that during curing, bone cement can polymerize away from the stem/cement interface generating radial stress in tension or gaps. The results demonstrate the reverse direction of polymerization for preheated stems. Stem preheating significantly increases transient temperatures at the bone/cement interface and also the risk of bone thermal necrosis, because the exposure time to high temperature is prolonged. The results provide interfacial characteristics for accurate modeling of bone cement polymerization to better understand the debonding process of cemented hip prostheses. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Preparation of chitosan scaffolds with a hierarchical porous structure
Authors: Ko Young‐Gwang , Kawazoe Naoki , Tateishi Tetsuya , Chen Guoping
Published: January 2010

Development of porous scaffolds with open surface pore structures is required for tissue engineering to deliver cells into the three‐dimensional spaces in the scaffolds and improve cell distribution. This study demonstrated a new type of funnel‐like chitosan sponge prepared using ice particulates as a template. The funnel‐like chitosan sponges had a hierarchical bilayer porous structure of a surface layer and an interconnected bulk porous layer. The top surface porous layer consisted mainly of large open pores. The bulk porous layer was beneath the large surface pores and consisted of small pores that were connected with the large surface pores. The large surface pores were dependent on the shape, dimension, and density of the embossing ice particulates, while the bulk pores were dependent on the freezing temperature. The large open surface pores and interconnected bulk pores in the funnel‐like chitosan sponges facilitated cell seeding and cell distribution from the surface into the inner bulk pores. Cells cultured in the funnel‐like chitosan sponges showed high viability, high proliferation, and homogenous tissue formation. Such funnel‐like chitosan sponges will be useful for tissue engineering. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Retracted: Push‐out bond strengths of two fiber post types bonded with different dentin bonding agents
Authors: Topcu Fulya Toksoy , Erdemir Ugur , Sahinkesen Gunes , Mumcu Emre , Yildiz Esra , Uslan Ibrahim
Published: January 2010

The following article from Journal of Biomedical Materials Research Part B: Applied Biomaterials, “Push‐out bond strengths of two fiber post types bonded with different dentin bonding agents” by Fulya Toksoy Topcu, Ugur Erdemir, Gunes Sahinkesen, Emre Mumcu, Esra Yildiz, and Ibrahim Uslan, published online on January 20, 2010, in Wiley Online Library (www.wiley onlinelibrary.com ), DOI: 10.1002/jbm.b.31590, and in Volume 93(2), pp. 359–366, has been retracted by agreement between the authors, the journal Editor‐in‐Chief, Jeremy L. Gilbert, and Wiley Periodicals, Inc.

While the hypothesis, materials and methods, and results of this work have not been called into question, the paper contained unattributed overlap with Akgungor G, Akkayan B. Influence of dentin bonding agents and polymerization modes on the bond strength between translucent fiber posts and three dentin regions within a post space. J Prosthet Dent. 2006 May;95(5):368–378.

This error was not identified by the authors prior to publication and does not have a direct impact on the merits of the experimental work described.
Withdrawn: ABCA4 is ubiquitously expressed in mouse tissues and forms high molecular weight complexes
Authors: Lechward Katarzyna A. , Glaser Walter , Falkner Susanne
Published: January 2010

Notice of withdrawal: The following article from Journal of Cellular Biochemistry, “ABCA4 is ubiquitously expressed in mouse tissues and forms high molecular weight complexes” by Lechward K et al., published online on 20 Jan 2010 in Wiley InterScience (www.interscience.wiley.com), has been withdrawn by agreement between the journal Editor‐in‐Chief, Dr. Gary S Stein and Wiley Liss, Inc.

Dr. Gary S Stein,
Editor‐in‐Chief,
Journal of Cellular Biochemistry
SnCl2 · 2H2O‐catalyzed one‐pot synthesis of 4(3H)‐quinazolinones from anthranilic acid, ortho esters, and amines under solvent free conditions
Authors: Wang Min , Song Zhiguo , Zhang Tingting
Published: January 2010

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A simple, efficient, and green procedure for the one‐pot synthesis of 4(3H)‐quinazolinones by three components condensation of anthranilic acid, ortho esters, and amines in the presence of SnCl2 · 2H2O has been developed. The reaction occurred within short reaction time at room temperature under solvent‐free conditions to afford the title products in excellent yields. J. Heterocyclic Chem., (2010).
Role of MEK‐ERK pathway in morphine‐induced conditioned place preference in ventral tegmental area of rats
Authors: Lin XiaoJing , Wang QingSong , Ji Jianguo , Yu Long‐Chuan
Published: January 2010

A major goal of research on drug addiction is to develop the effective treatments to deal with the long‐term behavioral disorders especially reinstatement induced by the addictive drugs such as opiates, cocaine, and cannabinoid. The molecular mechanisms underlying these substance‐related disorders remain unclear so far. Here we used the model of morphine‐induced conditioned place preference (CPP) in rats to mimic the progress of drug‐taking, withdrawal and relapse in human. The tissue of ventral tegmental area (VTA), one of the most important brain structures associated with abused drug‐related disorders, was taken and two‐dimensional electrophoresis (2‐DE) was performed to analyze and compare the changes of protein expression patterns during the different stages of morphine‐induced CPP. First, we found that there were 80 proteins identified to be changed in the process of morphine‐induced CPP. Furthermore, as the mitogen‐activated protein kinase kinase 1 (MAPKK1) was increased significantly in the stages of establishment and reinstatement, we confirmed the change of activated extracellular signal‐regulated kinase (ERK) by Western blotting in VTA tissue and cultured cell. The results demonstrated that the activated MEK‐ERK pathway by chronic morphine treatment in VTA was involved in morphine‐induced reinstatement. Moreover, inhibition of MEK‐ERK pathway by infusion the MEK inhibitor U0126 in VTA blocked the establishment of morphine‐induced CPP. The present study found significant changes in a group of protein expressions in VTA during morphine‐induced CPP and further confirmed the role of MEK‐ERK cell signaling pathway of VTA in morphine addiction. © 2010 Wiley‐Liss, Inc.
Acoustic overstimulation modifies Mcl‐1 expression in cochlear sensory epithelial cells
Authors: Hu Bo Hua , Cai Qunfeng
Published: January 2010

Acoustic overstimulation causes apoptotic cell death in the cochlea. This death process is mediated, in part, by the mitochondrial signaling pathway involving Bcl‐2 family proteins. Myeloid cell leukemia sequence 1 (Mcl‐l) is an antiapoptotic member of the Bcl‐2 family. Its involvement in noise‐induced hair cell death has not been characterized. Here we report the endogenous expression and the noise‐induced expression of Mcl‐1 in Sprague Dawley rat cochleae. In the sensory epithelia of normal cochleae, there is strong constitutive expression of Mcl‐1 mRNA, with an expression level higher than that of many other Bcl‐2 family genes. The Mcl‐1 protein is preferentially expressed in outer hair cells. After exposure to a high level of continuous noise at 115‐dB sound pressure level for 1 hr, Mcl‐1 expression displays a time‐dependent alteration, with up‐regulation of Mcl‐1 mRNA at 4 hr postexposure and protein up‐regulation at 1 day postexposure. Western blot analysis reveals the up‐regulated Mcl‐1 as the full‐length form of Mcl‐1. Immunolabeling of the Mcl‐1 protein reveals the early increase in Mcl‐1 immunoreactivity in the nuclear region of the hair cells displaying apoptotic phenotypes and a subsequent increase in survival hair cells. These results suggest that Mcl‐1 is involved in the regulation of hair cell pathogenesis resulting from acoustic stress, possibly by influencing the nuclear events of apoptosis. © 2010 Wiley‐Liss, Inc.
Formal ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma
Authors: Gibbard Philip L. , Head Martin J. , Walker Michael J. C. ,   the Subcommission on Quaternary Stratigraphy
Published: January 2010

In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS) formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period to the Global Stratotype Section and Point (GSSP) of the Gelasian Stage/Age at Monte San Nicola, Sicily, Italy. The Gelasian until then had been the uppermost stage of the Pliocene Series/Epoch. The base of the Gelasian corresponds to Marine Isotope Stage 103, and has an astronomically tuned age of 2.58 Ma. A proposal that the base of the Pleistocene Series/Epoch be lowered to coincide with that of the Quaternary (the Gelasian GSSP) was also accepted by the IUGS Executive Committee. The GSSP at Vrica, Calabria, Italy, which had hitherto defined the basal boundary of both the Quaternary and the Pleistocene, remains available as the base of the Calabrian Stage/Age (now the second stage of the revised Pleistocene). In ratifying these proposals, the IUGS has acknowledged the distinctive qualities of the Quaternary by reaffirming it as a full system/period, correctly complied with the hierarchical requirements of the geological timescale by lowering the base of the Pleistocene to that of the Quaternary, and fully respected the historical and widespread current usage of both the terms ‘Quaternary’ and ‘Pleistocene’. Copyright © 2009 John Wiley & Sons, Ltd.
Isolation of inulin‐type oligosaccharides from Chinese traditional medicine: Morinda officinalis How and their characterization using ESI‐MS/MS
Authors: Yang Zhenmin , Yi Yongtao , Gao Chuanchuan , Hou Dengke , Hu Jun , Zhao Mingyue
Published: January 2010

Inulin‐type oligosaccharides with different DP were prepared by size‐exclusion chromatography and purity of each oligosaccharide was determined by HPLC equipped with cyclodextrin‐bond column. The purities of obtained inulin‐type oligosaccharides with different DP were more than 98% by one‐step process. The DP and molecular weight were obtained through ESI‐MS in negative mode. The characterization of the inulin‐type oligosaccharides with different DP was studied by MS/MS spectra obtained by collision‐induced dissociation of molecular ions ([M−H]−). When the DP was lower, the fragment ions were formed through cross‐ring cleavages of two bonds within the sugar ring and glycosidic cleavages. However, with the increase of DP, the ions resulting from glycosidic cleavages between two sugar residues were predominant.
Investigation on nanocrystalline iron‐cobalt‐vanadium alloy processed by equal channel angular pressing (ECAP)
Authors: Jiacai K. , Zhongze D.
Published: January 2010

Nanocrystalline iron‐cobalt‐vanadium alloy was fabricated by Equal‐Channel Angular Pressing (ECAP). Microstructural evolution at different passes of ECAP and the effect of φ in the ECAP were researched. The results revealed that a phase slowly turned to γ phase and followed the form of dislocation cells in the iron‐cobalt‐vanadium alloy with the increase of severe plastic deformation. At last, it became reasonably finer bands of subgrains. The results with intersect at an angle φ of 90° was better than with at an angle φ of 120°. After three passes of ECAP, at an angle φ of 90°, the nanocrystalline microstructure could be obtained. The grain size was reduced from 30 μm in the initial state to 400nm.
Short‐term creep behavior of chromium rich hot‐work tool steels
Authors: Wurmbauer H. , Panzenböck M. , Leitner H. , Scheu C. , Clemens H.
Published: January 2010

Hot‐work tool steels represent a group of steels which are used for metal forming operations at elevated temperatures, e. g. die casting, extrusion molding and drop forging. During application such working tools are exposed for a short time to both high temperatures and mechanical stresses. Short‐term creep tests of two chromium rich martensitic hot‐work tool steels which basically differ in their molybdenum, carbon and silicon content were conducted at temperatures in the range of 540°C to 600°C and at stress levels ranging from 280 MPa to 600 MPa. Both steels showed a minimum strain rate, at approximately 1/6 time to rupture, instead of a steady‐state creep range. The stress exponents of both steels indicate dislocation creep as the dominant creep mechanism. Microstructural investigations showed that in both steels the secondary hardening carbides are type of MC and M2C. A higher content of molybdenum and carbon causes a higher volume fraction of these carbides and results in a better short‐term creep behavior.

Warmarbeitsstähle werden häufig als Werkzeuge beim Druckgießen, Strangpressen oder Gesenkschmieden eingesetzt. Während des Einsatzes sind diese Stähle immer wieder hohen Temperaturen und Spannungen ausgesetzt. In dieser Arbeit wurden an zwei chromreichen Warmarbeitsstählen, welche sich hauptsächlich in ihrem Molybdän‐, Kohlenstoff‐ und Siliziumgehalt voneinander unterscheiden, Kurzeitkriechversuche durchgeführt. Die Versuchstemperaturen lagen dabei zwischen 540°C und 600°C, währenddessen die Spannungen von 280 MPa bis 600 MPa reichten. Bei beiden Stählen trat eine minimale Kriechrate bei ungefähr einem Sechstel der Bruchzeit auf. Ein konstanter sekundärer, so genannter „Steady‐State”︁, Kriechbereich wurde bei keinem der durchgeführten Kriechversuche festgestellt. Der Spannungsexponent von beiden Stählen weist auf Versetzungskriechen als den dominierenden Kriechprozess hin. Untersuchungen der Mikrostruktur an beiden Stählen ergaben Sekundärhärtekarbide vom Typ MC und M2C. Ein erhöhter Molybdän und Kohlenstoffgehalt führt zu einem höheren Volumenanteil an diesen Karbiden, verbunden mit einem besseren Kurzzeitkriechverhalten.
Mathematical model for calculating the strength of a single lap adhesive joint intended for the service in sea water
Authors: Kožuh Z. , Kralj S. , Garašic I. , Dorn L.
Published: January 2010

The application of adhesives in the joining of materials is limited not only by the impossibility of accurately calculating the strength of an adhesive bonded joint, but also by incomplete knowledge of effect of service conditions upon degradation of adhesive forces. This is particularly true for adhesive bonded joints intended for service in sea water. In the introductory part of the paper, the effects of liquids upon the strength of adhesive bonded joints are described as reported in the reference publications. Difficulties encountered in using adhesive bonded joints in liquids and other media with high humidity are considered. In the experimental part of the paper, the authors endeavour to explain the effects of sea water upon the strength of single lap adhesive bonded joints of high alloyed steel.

Neben der Unmöglichkeit der exakten Klebungsfestigkeitsberechnung, ist die Unkenntnis der Adhäsionsschwächung mit der Zeit eine Einschränkung für die Klebtechnikanwendung insbesondere bei der Anwendung unter Meerwasser. In der Einführung dieser Arbeit wird die Auswirkung von Flüssigkeiten auf die Klebfestigkeit nach Literaturangaben beschrieben und es werden die Schwierigkeiten bei der Klebanwendung in Flüssigkeiten und Medien mit großer Feuchtigkeit angezeigt. Im experimentellen Teil der Arbeit wird untersucht wie sich die Meereswassereinwirkung auf die Festigkeit von einschnittig überlappten Klebverbindungen an hochlegierten Stählen auswirkt.
Mathematical‐physical model of resistance sintering with current conducting electrode punches of steel ceramic composites
Authors: Guk S. , Yanina A. , Müller W. , Kawalla R.
Published: January 2010

Im Rahmen der dargestellten Untersuchungen wurde das konduktive Sintern eines TRIP‐Matrix‐Composites auf der Basis eines austenitischen nichtrostenden Stahls mit TRIP‐Effekt und einer MgO‐teilstabilisierten ZrO2‐Keramik durchgeführt. Der Einfluss des Keramik‐Anteiles auf die Temperaturentwicklung, der im Bereich zwischen 5 und 20%‐Vol. variiert worden ist, wurde anhand von Experimenten ermittelt und durch Aufstellen eines mathematisch‐physikalischen Modells verallgemeinert. Die Ergebnisse zeigten eine sehr gute Übereinstimmung mit dem Experiment. Damit lässt sich eine vollständige Beschreibung der Temperaturverteilung und ‐entwicklung während des konduktiven Sinterns eines Stahl‐Keramik‐Composites näherungsweise durchführen, um letztlich zur Auswahl optimaler Aufheizprozesse, die sich durch einen geringen Temperaturgradienten über den Probenquerschnitt kennzeichnen, beizutragen. Diese Methodik kann einen nützlichen Beitrag zur Beherrschung einer optimalen Sintertechnologie leisten.

In the present study the resistance sintering of TRIP‐Matrix‐composites on the base of non‐rusting austenitic steel with TRIP‐effect and MgO‐partial‐stabilized ZrO2 ceramic was carried out. The influence of the ceramics containing, which has been varied in the area between 5 and 20%‐Vol., on the temperature development, was determined on the basis of experiments and was generalised by putting up a mathematical‐physical model. The results showed a very good correspondence with the experiment. With it lets made an entire approximately description of the temperature distribution and temperature development itself during the resistance sintering of a steel‐ceramic‐composites to contribute optimum of heating rate which marks itself by a low temperature gradient about the test cross section. This methodology is able to do a useful contribution to the control of optimum sinter technology.
Vascular pedicle avulsion in free flap breast reconstruction: A case of diep flap salvage following early avulsion of venous anastomosis and literature review
Authors: Lykoudis Efstathios G. , Ziogas Dimosthenis E. , Papanikolaou George E.
Published: January 2010

Free flap vascular pedicle avulsion represents an extremely rare complication in reconstructive microsurgery. Very few cases have been reported in the literature, most of them identified in free flap breast reconstruction. As a result, little data is currently available on the etiology and treatment of this rare complication. Herein, we report a unique case of early venous anastomosis avulsion following free DIEP flap transfer for delayed breast reconstruction. Venous outflow was successfully restored with the use of an interposition vein graft, and the flap survived completely. In addition, the relevant literature is reviewed; and the possible causes, preventive strategies, and management options are analyzed. © 2010 Wiley‐Liss, Inc. Microsurgery 2010.
Foot anomalies in the Late Neolithic/Chalcolithic population exhumed from the rock cut cave of São Paulo 2 (Almada, Portugal)
Authors: Silva A. M.
Published: January 2010

The study of developmental abnormalities of the tarsal bones in a Portuguese Late Neolithic population was performed, as part of an ongoing research project that includes the evaluation of foot defects in Portuguese skeletal populations from Neolithic times to modern 20th century samples. Two accessory bones were found, calcaneum secundarium and os trigonum, and three non‐osseous coalitions were detected, calcaneonavicular, cuboid‐navicular and third metatarsal‐third cuneiform. The newly presented frequencies corresponded to other published sources, except for the frequency of calcaneum secundarium, higher than in previous studies (8.6% left bones; 15.2% right bones). This result suggests population homogeneity maybe due to geographic isolation and/or marriage customs although the exact pattern of inheritance of the majority of these foot anomalies is unknown. No apparent sex bias was detected and side could not be tested since these human remains were uncovered from a commingled funerary context. Copyright © 2010 John Wiley & Sons, Ltd.
Pyrroline‐5‐carboxylate synthase and proline biosynthesis: From osmotolerance to rare metabolic disease
Authors: Pérez‐Arellano Isabel , Carmona‐Álvarez Francisco , Martínez Ana I. , Rodríguez‐Díaz Jesús , Cervera Javier
Published: January 2010

Pyrroline‐5‐carboxylate synthase (P5CS) is a bifunctional enzyme that exhibits glutamate kinase (GK) and γ‐glutamyl phosphate reductase (GPR) activities. The enzyme is highly relevant in humans because it belongs to a combined route for the interconversion of glutamate, ornithine and proline. The deficiency of P5CS activity in humans is associated with a rare, inherited metabolic disease. It is well established that some bacteria and plants accumulate proline in response to osmotic stress. The alignment of P5CSs from different species and analysis of the solved structures of GK and GPR reveal high sequence and structural conservation. The information acquired from different mutant enzymes with increased osmotolerant properties, together with the position of the insertion found in the longer human isoform, permit the delimitation of the regulatory site of GK and P5CS and the proposal of a model of P5CS architecture. Additionally, the GK moiety of the human enzyme has been modeled and the known clinical mutations and polymorphisms have been mapped.
Thermodynamic resolution: How do errors in modeled protein structures affect binding affinity predictions?
Authors: Singh Manoj Kumar , Dominy Brian N.
Published: January 2010

The present study addresses the effect of structural distortion, caused by protein modeling errors, on calculated binding affinities toward small molecules. The binding affinities to a total of 300 distorted structures based on five different protein–ligand complexes were evaluated to establish a broadly applicable relationship between errors in protein structure and errors in calculated binding affinities. Relatively accurate protein models (less than 2 Å RMSD within the binding site) demonstrate a 14.78 (±7.5)% deviation in binding affinity from that calculated by using the corresponding crystal structure. For structures of 2–3 Å, 3–4 Å, and >4 Å RMSD within the binding site, the error in calculated binding affinity increases to 20.8 (±5.98), 22.79 (±11.3), and 29.43 (±11.47)%, respectively. The results described here may be used in combination with other tools to evaluate the utility of modeled protein structures for drug development or other ligand‐binding studies. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Significantly decreased production times for a‐Si/µc‐Si tandem cells on texture‐etched ZnO:Al
Authors: Gordijn A. , Schicho S. , Muthmann S. , Kilper T. , Zhu H. , Bunte E. , Hüpkes J.
Published: January 2010

Several approaches that lead to shorter production times of a‐Si/µc‐Si tandem cells are combined in this paper: high‐rate sputtering of aluminum‐doped zinc oxide, high‐rate 40 MHz plasma deposition of microcrystalline silicon and reduced i‐layer thicknesses. On standard lab‐type texture‐etched ZnO:Al, 1 cm2 a‐Si:H/µc‐Si:H tandem test cells on a deposition area of 30 × 30 cm2 were made that showed an initial efficiency of 9.9%, whereas the total effective deposition time of intrinsic layers was only 22 min (15 min for the top cell and 7 min for the bottom cell). The silicon thickness is only 600 nm. On high‐rate texture‐etched ZnO:Al an efficiency of 9.4% initial was reached. Standard light‐induced degradation experiments showed a degradation rate of only 5.5–7.9% after 1000 h. This regime of very short preparation times and relatively high‐stabilized efficiencies is highly interesting from the production point‐of‐view.
Structural order on different length scales in amorphous silicon investigated by Raman spectroscopy
Authors: Muthmann S. , Köhler F. , Carius R. , Gordijn A.
Published: January 2010

Parameters for the structural short (SRO) and medium range order (MRO) of hydrogenated amorphous silicon (a‐Si:H) films on the edge of the microcrystalline silicon (µc‐Si:H) phase transition were studied with Raman spectroscopy. The observed samples were deposited using radio frequency plasma enhanced chemical vapor deposition. The studied films were grown with various constant and non‐constant silane concentrations (SCs). A substrate dependent correlation of SC to the intensity ratio (IMRO) of the transversal acoustical (TA) and the transversal optical (TO) phonon bands was found. A strong correlation between width and position of the (TO) phonon band was observed. These two easily accessible parameters show an increase of SRO when IMRO decreases.
Hydrogen distribution in the vicinity of dangling bonds in hydrogenated amorphous silicon (a‐Si:H)
Authors: Fehr M. , Schnegg A. , Teutloff C. , Bittl R. , Astakhov O. , Finger F. , Rech B. , Lips K.
Published: January 2010

We have investigated the distribution of H atoms around native dangling bonds in a‐Si:H by electron‐nuclear double resonance (ENDOR). In contrast to previous electron spin echo envelope modulation (ESEEM) studies [Isoya et al., Phys. Rev. B47(12), 7013–7024 (1993)] we find that the distance between H atoms and dangling‐bond defects can be well belowr = 3 Å. Our experimental data suggest that the H distribution is continuous and homogeneous and there is no indication for a short‐range order between H atoms and dangling bonds. This work is a first step toward the investigation of the H distribution around light‐induced defects to test models predicting the immediate proximity of H and defects.
A recombination model for a‐Si:H/c‐Si heterostructures
Authors: Leendertz C. , Stangl R. , Schulze T. F. , Schmidt M. , Korte L.
Published: January 2010

A semi‐analytical model to describe the excess carrier concentration‐dependent recombination processes and the charge carrier lifetime in a‐Si:H/c‐Si heterostructures has been developed. In contrast to previously proposed models it accounts for most relevant physical processes: In addition to bulk recombination processes the recombination via distributed dangling bond defects at the interface is integrated. Furthermore interface band bending depending on the a‐Si:H doping and the Fermi‐level dependent defect charge is taken into consideration as well as charge carrier diffusion to the interface. Despite its complexity the model allows for rapid computation and is thus well suited for fitting lifetime measurements in order to extract interface parameters. The model is crosschecked for various experimentally relevant situations against the numerical simulation tool AFORS‐HET (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of thin‐film silicon solar cells with white paint back reflectors
Authors: Lipovšek Benjamin , Krč Janez , Isabella Olindo , Zeman Miro , Topič Marko
Published: January 2010

In this work, we investigate the concept of transparent conductive oxide (TCO)/white paint (WP) back reflectors as an alternative to the conventional textured metal‐based reflectors in thin‐film silicon solar cells. The optical characterisation results show that WP back reflectors exhibit good reflectivity and excellent light scattering properties which can lead to enhanced light confinement within the thin absorber layers of the cell. To confirm this, ZnO:Al/WP reflectors with WP films of different pigment volume concentration and thickness are tested in thin‐film amorphous silicon solar cells. The external quantum efficiency measurements indicate that by employing ZnO:Al/WP reflectors, good solar cell performance can be achieved, which is comparable to the performance of the cell with the conventional TCO/Ag reflector. Finally, optical simulations are employed to study the potential for further improvements in cell performance as a result of the optimisation of TCO/WP reflectors. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal effects in Ge‐Sb‐Te phase‐ change memory materials during multiple thermal cycling
Authors: Kozyukhin Sergey , Sherchenkov Alexey , Gorschkova Ekaterina , Kudoyarova Vera , Vargunin Alexander
Published: January 2010

Phase transformations in (GeTe)m(Sb2Te3)n (m: n = 1:1; 1:2; 2:1) alloys and thin films on their basis were studied during thermal cycling by differential scanning calorimetry, and some thermal properties were determined. Exothermal peaks due to the amorphous → crystalline phase changes were observed in all thin films. In addition, reproducible endothermic peak in the range of 390‐415 °C was revealed in thin films as well as in bulk Ge2Sb2Te5, GeSb2Te4, GeSb4Te7 samples, which may influence on the kinetics and endurance of data reading processes in phase‐change memory devices. Activation energies of observed heat effects were estimated with using Kissinger's method, and nature of the given endothermic peak was discussed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gas‐temperature control in VHF‐ PECVD process for high‐rate (>5 nm/s) growth of microcrystalline silicon thin films
Authors: Sobajima Yasushi , Higuchi Takuya , Chantana Jakapan , Toyama Toshihiko , Sada Chitose , Matsuda Akihisa , Okamoto Hiroaki
Published: January 2010

Surface‐heating phenomenon by the radiation from high density plasma during growth of microcrystalline silicon (μc‐Si:H) thin films at high rate (> 5 nm/sec) is one of the crucial issues to be solved for obtaining high quality intrinsic‐layer material for solar cells. We have utilized an optical emission spectroscopy (OES) in the plasma to observe the time evolution of gas temperature during film growth as well as the film‐growth rate under μc‐Si:H deposition conditions at high rate. Gas temperature has been successfully controlled by changing total flow rate of monosilane (SiH4)/hydrogen (H2) gas mixture, leading to a drastic improvement of optoelectronic properties in the resulting μc‐Si:H. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport properties and photo‐ conductivity of nanocrystalline PbTe(In) films
Authors: Dobrovolsky Alexandr , Chernichkin Vladimir , Belogorokhov Ivan , Dashevsky Zinovi , Kasiyan Vladimir , Ryabova Ludmila , Khokhlov Dmitry
Published: January 2010

Microstructure, charge transport and photoelectric properties are studied for PbTe(In) films deposited on amorphous substrates kept at different temperatures Ts during deposition. All the films have a column‐like structure with the mean column diameter increasing from 60 nm at the lowest Ts = ‐120 °C up to 300 nm at the maximal Ts = 250 °C. The substrate temperature increase results in appearance of a preferred orientation of grains and in an inversion of the conductivity type from hole to electron. Electric transport and photoelectric properties of the films were studied in the temperature interval 4.2 – 300 K in DC and AC modes at frequencies varied from 20 Hz up to 1 MHz. The impedance spectra analysis was done in terms of the equivalent circuit model. Modification of charge transport mechanisms is correlated with the variation of microstructure of the films grown at different substrate temperatures. Films with disordered grains possess all features of non‐homogeneous systems, while the films with a preferred orientation of grains are analogous to PbTe(In) single crystals in their transport and photoelectric properties. Mechanisms of the persistent photoconductivity observed in the films are qualitatively distinguished. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical and photoelectric properties of nanocrystalline SnO2 ‐ CdSe quantum dot structures
Authors: Dobrovolsky Alexandr , Vasiliev Roman , Drozdov Konstantin , Maslova Olga , Rumyantseva Marina , Gaskov Alexander , Ryabova Ludmila , Khokhlov Dmitry
Published: January 2010

Microstructure, optical and photoelectric properties of nanocrystalline porous SnO2 films on an insulating substrate with colloidal CdSe quantum dots as a sensitizer have been studied. SnO2 films consist of nanocrystallites with the average size of ∼20 nm combined into agglomerates as large as ∼1 µm. CdSe quantum dots with themean size of ∼3.5 nm were incorporated into porous SnO2 films by dipping the substrates into a colloidal solution of CdSe quantum dots. Transport and photoelectric properties of the structures were studied in the temperature interval 77 – 300 K. Optical properties were investigated in the visible spectral range. Persistent photoconductivity at the room temperature has been observed. Possible mechanisms of the persistent photoconductivity for this composite system are discussed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Breviscapine‐induced apoptosis of human hepatocellular carcinoma cell line HepG2 was involved in its antitumor activity
Authors: Wu Yulin , Fan Qianqian , Lu Na , Tao Lei , Gao Yuan , Qi Qi , Guo Qinglong
Published: January 2010

Breviscapine is a flavonoid constituent isolated from a traditional Chinese herbErigerin breviscapus(Vant.) Hand‐Mazz. To investigate the apoptosis‐inducing effect of breviscapine on human hepatocellular carcinoma cell line HepG2 and explore the relative molecular mechanisms. HepG2 cells were treated with breviscapine at different concentrations and the inhibitory rate was analyzed by MTT assay. The morphological changes in cells were observed under an inverted light microscope and a fluorescence microscope and the apoptosis rate were detected by flow cytometry. Western blot was used to evaluate the protein expression. The viability of HepG2 cells was markedly inhibited in a concentration‐dependent manner and obvious morphological changes were confirmed, including condensed chromatin and reduction in volume. The increased percentage of apoptotic cells was displayed by flow cytometry and the altered expression level of several apoptosis‐associated proteins, Bcl‐2, Bax and caspase‐3, was detected by western blot. It is first discovered that breviscapine exhibited potential antitumor activity, induces remarkable apoptosis in HepG2 cells and promises to be a new candidate in future cancer therapy. Copyright © 2010 John Wiley & Sons, Ltd.