bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison Between Different Syntesis Methods of PMMA/HA Using Ultrasonic Radiation
Authors: Albano C. , Parra C. , González G.
Published: March 2010

Summary:The use of PMMA as dental and osseous cement and also in the fabrication of intraocular lenses has been widely reported. The combination of its excellent properties with those of hydroxyapatite (HA) to form a composite material, can result in very interesting properties as a biomaterial. The key is to obtain a good filler dispersion and interface bonding. Ultrasonic radiation seems to be a very versatile method for the synthesis of these materials, since the use of conventional initiators can be avoided, the filler dispersion improved and the interface interaction can be promoted. In the present work PMMA/HA composite materials were prepared by three different synthesis routes using ultrasonic radiation, in order to study the effect of the synthesis method on the final microstructure.Method I:in situsynthesis of PMMA and HA, under ultrasonic radiation by emulsion polymerization of MMA and HA precursors.Method II:in situsynthesis of HA, (from its precursors) by high frequency ultrasound in commercial PMMA solutionMethod III:in situpolymerization of MMA under high frequency ultrasonic radiation and adding HA to the solution andMethod IVMixing of hydroxyapatite nanocrystals, in different proportions, in a solution of commercial PMMA, by different periods from 10 min to 7 h, under low frequency (conventional) ultrasonic radiation, to compare the effect of high frequency and conventional ultrasound radiation. The different materials were characterized by FTIR, SEM, TEM, DRX,1H NMR and TGA. The results showed that, all the composites prepared byin situsynthesis showed an interaction between HA and PMMA, manifested by a bonding of the phosphate groups with the polar groups of the polymer matrix observed by FTIR. On the other hand, when the synthesis was carried out simultaneously adding HA and PMMA precursors a inhibition of the polymerization reaction of MMA was observed.
Evaluation of Biodegradability of Different Blends of Polystyrene and Starch Buried in Soil
Authors: Oliveira C. I. R. , Cunha F. R. , Andrade C. T.
Published: March 2010

Summary: Polystyrene/cornstarch blends were prepared by melt‐processing in the presence of maleic anhydride (MA), using an internal mixer as reactor. Scanning electron microscopy (SEM) was used to visualize the blends morphology. Addition of MA contributed to improve interfacial adhesion between the two phases. Soil burial tests were used to investigate biodegradability. Results from samples weight loss, as a function of incubation time, revealed that the increase in the content of starch contributed to increase biodegradability. The results showed that the microbial activity inside the specimens was accelerated in the first 15 days of evaluation. Photographs of the films showed significant differences after 30 days of incubation in soil. SEM was also used to evaluate biodegradation, and revealed fractured surfaces covered with a heterogeneous microorganism community.
Do MRI features distinguish Wilson's disease from other early onset extrapyramidal disorders? An analysis of 100 cases
Authors: Prashanth L.K. , Sinha S. , Taly A.B. , Vasudev M.K.
Published: March 2010

Magnetic resonance imaging (MRI) is frequently used in the evaluation of various extrapyramidal disorders. Among the plethora of MRI features in Wilson's disease (WD), only “face of the giant panda” sign has been recognized to distinguish WD from other early onset extrapyramidal disorders (EOEPD). To ascertain the value of various MRI features in differentiating neuropsychiatric form of WD from other EOEPD. This retrospective analysis included 100 patients (M:F = 56:44) of EOEPD (5–40 years), who had undergone MRI during Jan'03 to Nov'08. Their clinical features were recorded and the following MR sequences were analyzed: T1WI, T2WI, FLAIR. Fifty‐six patients had WD (M:F = 28:30, age at onset: 14 ± 6.8 years) and 44 had other EOEPD (M:F = 27:17, age at onset: 19 ± 9.8 years) that included Huntington's disease‐4, young‐onset Parkinson's disease‐7, mitochondrial disorders‐2, Hallervorden‐Spatz disease‐8, non‐Wilsonian hepatolenticular degeneration‐2, toxic/metabolic disorder‐1, and others‐20. The duration of illness at the time of MRI was comparable (WD: 3.1 ± 4.9 years; Other EOEPD: 2.8 ± 2.4 years). MR signal characteristics varied in topography and severity in both the groups. All the patients of WD had signal abnormalities in MRI, as against 16/44 of the other EOEPD group. The following MR observations were noted exclusively in WD: “Face of giant panda” sign (14.3%), tectal plate hyperintensity (75%), central pontine myelinolysis (CPM)‐like abnormalities (62.5%), and concurrent signal changes in basal ganglia, thalamus, and brainstem (55.3%). Besides “Face of giant panda” sign, hyperintensities in tectal‐plate and central pons (CPM‐like), and simultaneous involvement of basal ganglia, thalamus, and brainstem are virtually pathognomonic of WD. © 2010 Movement Disorder Society
Imaging essential tremor
Authors: Isaias Ioannis U. , Marotta Giorgio , Hirano Shigeki , Canesi Margherita , Benti Riccardo , Righini Andrea , Tang Chengke , Cilia Roberto , Pezzoli Gianni , Eidelberg David , Antonini Angelo
Published: March 2010

To investigate over time changes in striatal dopamine transporter (DAT), we performed two sequential N‐ω‐fluoropropyl‐2β‐carbomethoxy‐3β‐(4‐iodophenyl) tropane single photon computed tomography (SPECT) scans in 20 subjects with essential tremor (ET), in 13 with Parkinson disease (PD) and in 23 healthy controls (HC, one scan only). We also performed an [99mTc]ethyl cysteinate dimer bicisate SPECT exam for regional brain network analysis in 9 ET, in a second group of 18 PD (9 with tremor, tPD and 9 akinetic‐rigid dominant, arPD) and in 8 HC. PD subjects had a reduced DAT binding in comparison to ET and HC with an annual decline rate of 7.3% in the contralateral putamen. There were no mean uptake differences between ET and HC at baseline and no uptake loss over time in ET. A discriminant analysis grouped 30% (first scan) and 5% (second scan) of ET as PD and a partition analysis showed overlap between ET and PD for caudate nucleus uptake. Spatial covariance analysis revealed that the expression of the PD‐related regional pattern separated both tPD and arPD from ET and HC. In conclusion, PD and ET do not share a common pattern of dopaminergic loss over time. However, mild impairment of dopamine transporter in the caudate nucleus may contribute to tremor onset in ET. © 2010 Movement Disorder Society
Movement disorders and pregnancy: A review of the literature
Authors: Kranick Sarah M. , Mowry Ellen M. , Colcher Amy , Horn Stacy , Golbe Lawrence I.
Published: March 2010

Pregnant patients are rarely encountered in the movement disorders clinic, but they present significant dilemmas regarding treatment and counseling for neurologists. While movement disorders in pregnancy once described those disorders arising de novo during pregnancy, such as chorea gravidarum or restless leg syndrome, advancing maternal age in Western countries will likely increase the number of women in whom pregnancy complicates a pre‐existing movement disorder. Physicians treating these women must be aware of the impact of the movement disorder and its treatment on fertility, pregnancy, fetal development, lactation, and infant care. This review summarizes retrospective series and case reports to both guide clinicians and to stimulate and direct the design of prospective studies. © 2010 Movement Disorder Society
Increased 5‐HT2Areceptors in the temporal cortex of parkinsonian patients with visual hallucinations
Authors: Huot Philippe , Johnston Tom H. , Darr Tayyeba , Hazrati Lili‐Naz , Visanji Naomi P. , Pires Donna , Brotchie Jonathan M. , Fox Susan H.
Published: March 2010

Well‐formed visual hallucinations (VH) are common in patients with Parkinson's disease (PD). The pathophysiology of VH in PD is unknown but may involve structures mediating visual processing such as the inferior temporal cortex. Serotonergic type 2A (5‐HT2A) receptors have been linked to many psychiatric disorders, including psychosis. We hypothesized that enhanced 5‐HT2Areceptor levels may be involved in VH in PD. Autoradiographic binding using [3H]‐ketanserin and spiperone, to define 5‐HT2Areceptors, was performed in 6 PD patients with VH, 6 PD patients without VH, and 5 healthy, age‐matched controls. The cerebral regions studied included the orbitofrontal cortex, inferolateral temporal cortex, motor cortex, striatum, and substantia nigra. There was a significant (45.6%) increase in the levels of [3H]‐ketanserin binding in the inferolateral temporal cortex of PD patients with VH when compared with PD patients without VH (54.3 ± 5.2 fmol/mg vs. 37.3 ± 4.3 fmol/mg,P= 0.039). Additionally, there was a significant increase in the levels of 5‐HT2Areceptors in the motor cortex of all PD patients taken as a group when compared with controls (57.8 ± 5.7 fmol/mg vs. 41.2 ± 2.6 fmol/mg,P= 0.0297). These results suggest that enhanced 5‐HT2A‐mediated neurotransmission in the inferolateral temporal cortex, a critical structure in visual processing, might be associated with the development of VH in PD. Our results provide new insights into the pathophysiology of VH in PD and provide an anatomical basis to explain why compounds with 5‐HT2Aantagonist activity are effective at alleviating this debilitating complication. © 2010 Movement Disorder Society
Types of lymphoscintigraphy and indications for lymphaticovenous anastomosis
Authors: Maegawa Jiro , Mikami Taro , Yamamoto Yasushi , Satake Toshihiko , Kobayashi Shinji
Published: March 2010

Several authors have reported the usefulness and benefits of lymphoscintigraphy. However, it is insufficient to indicate microvascular treatment based on lymphedema. Here, we present the relationships between lymphoscintigraphic types and indications for lymphatic microsurgery. Preoperative lymphoscintigraphy was performed in 142 limbs with secondary lymphedema of the lower extremity. The images obtained were classified into five types. Type I: Visible inguinal lymph nodes, lymphatics along the saphenous vein and/or collateral lymphatics. Type II: Dermal backflow in the thigh and stasis of an isotopic material in the lymphatics. Type III: Dermal backflow in the thigh and leg. Type IV: Dermal backflow in the leg. Type V: Radiolabeled colloid remaining in the foot. Lymphaticovenous anastomosis was performed in 35 limbs. The average number of anastomoses per limb was 3.3 in type II, 4.4 in type III, 3.6 in type IV, and 3 in type V. The highest number of anastomosis was performed in type III. In conclusion, type III is suggested to be the best indication for anastomosis compared with types IV and V. © 2010 Wiley‐Liss, Inc. Microsurgery 30:437–442, 2010.
A case of intraoperative venous congestion of the entire DIEP‐flap—A novel salvage technique and review of the literature
Authors: Momeni Arash , Lee Gordon K.
Published: March 2010

The deep inferior epigastric perforator (DIEP) flap is gaining popularity for autologous breast reconstruction as it reportedly reduces abdominal donor site morbidity when compared with the transverse rectus abdominis musculocutaneous (TRAM) flap. Disadvantages include greater technical difficulties during flap harvest and a greater incidence of vascular compromise. A well‐known and feared complication is venous congestion which requires immediate intervention. We present a novel salvage technique in a case of total flap venous congestion in the setting of absent drainage via the deep inferior epigastric vein (DIEV). Utilizing the superficial venous system via the superficial inferior epigastric vein (SIEV) and using the DIEV as a venous interposition graft resulted in successful salvage of the DIEP flap. © 2010 Wiley‐Liss, Inc. Microsurgery 30:443–446, 2010.
Novel Approach for Clustering Zeolite Crystal Structures
Authors: Lach‐hab M. , Yang S. , Vaisman I. I. , Blaisten‐Barojas E.
Published: March 2010

Informatics approaches play an increasingly important role in the design of new materials. In this work we apply unsupervised statistical learning for identifying four framework‐type attractors of zeolite crystals in which several of the zeolite framework types are grouped together. Zeolites belonging to these super‐classes manifest important topological, chemical and physical similarities. The zeolites form clusters located around four core framework types: LTA, FAU, MFI and the combination of EDI, HEU, LTL and LAU. Clustering is performed in a 9‐dimensional space of attributes that reflect topological, chemical and physical properties for each individual zeolite crystalline structure. The implemented machine learning approach relies on hierarchical top‐down clustering approach and the expectation maximization method. The model is trained and tested on ten partially independent data sets from the FIZ/NIST Inorganic Crystal Structure Database
Structural correlations for 1H, 13C and 15N NMR coordination shifts in Au(III), Pd(II) and Pt(II) chloride complexes with lutidines and collidine
Authors: Pazderski Leszek , Pawlak Tomasz , Sitkowski Jerzy , Kozerski Lech , Szłyk Edward
Published: March 2010

1H, 13C and 15N NMR studies of gold(III), palladium(II) and platinum(II) chloride complexes with dimethylpyridines (lutidines: 2,3‐lutidine, 2,3lut; 2,4‐lutidine, 2,4lut; 3,5‐lutidine, 3,5lut; 2,6‐lutidine, 2,6lut) and 2,4,6‐trimethylpyridine (2,4,6‐collidine, 2,4,6col) having general formulae [AuLCl3], trans‐[PdL2Cl2] and trans‐/cis‐[PtL2Cl2] were performed and the respective chemical shifts (δ1H, δ13C, δ15N) reported. The deshielding of protons and carbons, as well as the shielding of nitrogens was observed. The 1H, 13C and 15N NMR coordination shifts (Δ1Hcoord, Δ13Ccoord, Δ15Ncoord; Δcoord = δcomplex − δligand) were discussed in relation to some structural features of the title complexes, such as the type of the central atom [Au(III), Pd(II), Pt(II)], geometry (trans‐ or cis‐), metal‐nitrogen bond lengths and the position of both methyl groups in the pyridine ring system. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and NMR elucidation of novel pentacycloundecane‐based peptides
Authors: Altaib Mohamed S. , Arvidsson Per I. , Govender Thavendran , Maguire Glenn E. M. , Makatini Maya , Onajole Oluseye K. , Kruger Hendrik G.
Published: March 2010

The synthesis and NMR elucidation of two novel pentacycloundecane (PCU)‐based peptides are reported. The PCU cage amino acids were synthesised as racemates and the incorporation of the cage amino acid with (S)‐natural amino acids produced diastereomeric peptides. The diastereomeric ‘cage’ peptides were separated using preparative HPLC and the NMR elucidation of these PCU containing peptides are reported for the first time. The 1H and 13C NMR spectra showed series of overlapping signals of the cage skeleton and that of the peptide, making it extremely difficult to resolve the structure using one‐dimensional NMR techniques only. The use of two‐dimensional NMR techniques proved to be a highly effective tool in overcoming this problem. Copyright © 2010 John Wiley & Sons, Ltd.
Assignment and conformational investigation of asymmetric phenylindenylidene ruthenium complexes bearing N,O‐bidentate ligands
Authors: Hendrickx P. M. S. , Drozdzak R. , Verpoort F. , Martins J. C.
Published: March 2010

The NMR conformational study of three asymmetric phenylindenylidene ruthenium complexes 4.1–4.3, is presented. Complete 1H and 13C assignments could be obtained for 4.1–4.3 in benzene solution from multiple 2D homonuclear and heteronuclear NMR techniques. Our NMR analysis shows that each complex exists as a 55:45 mixture of two rotational isomers in slow exchange on the NMR chemical shift timescale. They are shown to be related by a 180° flip of the indenylidene ligand along the RuCR bond. Both rotational isomers can be discriminated by means of NOEs contacts between the various ligands coordinating to the Ru. By matching these stereospecific assignments to the chemical shift, a chemical shift based fingerprint of the isomers that may allow straightforward assignment of future asymmetric phenylindenylidene ruthenium complexes is proposed. Copyright © 2010 John Wiley & Sons, Ltd.
Localized electrical current propagation in anisotropically perturbed atmospheres
Authors: Zohdi T. I.
Published: March 2010

The trajectory of free atmospheric electrical currents, such as lightning and sparks, is strongly influenced by microscale events that occur at the current front. In particular, highly conductive pathways can occur at the free surface front due to dielectric breakdown. The specific directions of the local pathways are minutely perturbed, due to the gaseous, disordered, nature of the media at the small scale. This results in highly conductive, anisotropically perturbed, continuum‐level properties at the electrical current front. In this work, a model is developed to investigate the role of the resulting anisotropically perturbed conductivity at the propagation front on the overall trajectory of free atmospheric electrical currents. The approach is to relate the electrical current velocity to the local anisotropic conductivity at the propagation front and the surrounding electric field. The conductive anisotropy is decomposed into an isotropic ‘base state’ and an anisotropic perturbation. The current trajectory is shown to be governed by a set of non‐linear differential equations, for which a numerical solution scheme is developed. The difference between paths taken through anisotropically perturbed and isotropic media is analytically bounded and quantified numerically as a function of the magnitude of the anisotropic perturbation. The analysis and numerical experiments indicate that, in a statistical sense, the difference in the paths taken in anisotropically perturbed and isotropic media depends quasilinearly on the perturbation magnitude. Copyright © 2010 John Wiley & Sons, Ltd.
Linear viscoelasticity, probe tack, and extrusion flow results of SEBS copolymers
Authors: Arevalillo Alfonso , Fernández Mercedes , Muñoz María Eugenia , Santamaría Anton
Published: March 2010

Microphase‐separated poly(styrene‐b‐ethylene‐co‐butylene‐ b‐styrene) copolymers of different molecular weights with polystyrene (PS) volume fraction ϕ = 0.30 are investigated. Linear dynamic viscoelastic data reveal the blocking effect of the ordered PS microdomains, which produces a predominantly elastic response at low frequencies, associated with a mechanical relaxation. These results are correlated with tack and extrusion flow measurements, which involve polymer/metal adhesion processes. Nonlinearity implied in some experiments alters the ordered morphology of low molecular weight samples producing a viscous dominant behavior. Dissipation is reflected in viscous‐like adhesion and lack of viscoplastic response in extrusion flow experiments. For the highest molecular sample, only a rubbery or entangled state (G′ > G″ and G′ > 105 Pa) is observed in the linear viscoleastic regime. This is associated with the lack of adhesion seen in both, probe tack experiments and capillary flow measurements. This lack of adhesion gives rise to a plug‐flow as the polymer slips in the capillary wall. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Prediction of glass transition temperatures of aromatic heterocyclic polyimides using an ANN model
Authors: Liu Wanqiang
Published: March 2010

Aromatic heterocyclic polyimides are used extensively in industries for their excellent mechanical properties, high glass transition temperatures (Tg), and so on. A quantitative structure–property relationship (QSPR) model was developed to predict the Tg values with 54 aromatic heterocyclic polyimides by using an artificial neural network (ANN) back‐propagation algorithm. Fifty‐four aromatic heterocyclic polyimides were randomly divided into a training set (36) and a test set (18). Three molecular descriptors (the connectivity index X1A, the topological descriptor PW3, and the 3D‐MoRSE descriptor Mor09e) were selected to produce the mode. Simulated with the final optimum ANN model with 3‐3‐1 structure, the results show that the predicted Tg values are in good agreement with the experimental ones, with the root mean square errors (RMSEs) of 12.4 K (R = 0.935) and 16.4 K (R = 0.937) for the training set and the test set, respectively. POLYM. ENG. SCI., 50:1547–1557, 2010. © 2010 Society of Plastics Engineers
Quantitative milk proteomics – Host responses to lipopolysaccharide‐mediated inflammation of bovine mammary gland
Authors: Danielsen Marianne , Codrea Marius C. , Ingvartsen Klaus L. , Friggens Nicolas C. , Bendixen Emøke , Røntved Christine M.
Published: March 2010

Intramammary infusion of lipopolysaccharide (LPS) in cows induces udder inflammation that partly simulates mastitis caused by infection with Gram‐negative bacteria. We have used this animal model to characterize the quantitiative response in the milk proteome during the time course before and immediately after the LPS challenge. Milk samples from three healthy cows collected 3 h before the LPS challenge were compared with milk samples collected 4 and 7 h after the LPS challenge, making it possible to describe the inflammatory response of individual cows. Quantitative protein profiles were obtained for 80 milk proteins, of which 49 profiles changed significantly for the three cows during LPS challenge. New information obtained in this study includes the quantified increase of apolipoproteins and other anti‐inflammatory proteins in milk, which are important for the cow's ability to balance the immune response, and the upregulation of both complement C3 and C4 indicates that more than one complement pathway could be activated during LPS‐induced mastitis. In the future, this analytical approach may provide valuable information about the differences in the ability of individual cows to resist and recover from mastitis.
Unbearable suffering of patients with a request for euthanasia or physician‐assisted suicide: an integrative review
Authors: Dees Marianne , Vernooij‐Dassen Myrra , Dekkers Wim , van Weel Chris
Published: March 2010

Purpose: In the legal performance of the euthanasia procedure, unbearable suffering, one of the requirements of due care, is difficult to assess. Evaluation of the current knowledge of unbearable suffering is needed in the ongoing debate about the conditions on which EAS can be approved.

Methods: Using an integrative literature review, we evaluated publications with definitions of suffering in general or in end‐of‐life situations and with descriptions of suffering in the context of a request for EAS.

Data synthesis: From the 1482 citations identified, we included 55 publications: 20 articles about definitions of suffering and 35 empirical studies on suffering. We found no definition of unbearable suffering in the context of a request for EAS. Qualitative patient‐centered studies revealed the most motivations, and the most motivations named by only one of the three parties involved. The studies of relatives were limited, mainly quantitative and retrospective. We found no studies that brought together the views of the patients, relatives, and healthcare professionals.

Conclusions: There is no generally accepted definition of ‘unbearable suffering’ in the context of a request for EAS. On the basis of the articles reviewed, we propose the following conceptual definition: ‘Unbearable suffering in the context of a request for EAS is a profoundly personal experience of an actual or perceived impending threat to the integrity or life of the person, which has a significant duration and a central place in the person's mind’. Further patient‐centered qualitative research into suffering is needed to clarify this definition. Copyright © 2009 John Wiley & Sons, Ltd.
Crystal structure of the crenarchaeal conserved chromatin protein Cren7 and double‐stranded DNA complex
Authors: Feng Yingang , Yao Hongwei , Wang Jinfeng
Published: March 2010

Cren7 is a crenarchaeal conserved chromatin protein discovered recently. To explore the mechanism of the DNA packaging in Crenarchaeota, the crystal structure of Cren7–GCGATCGC complex has been determined and refined at 1.6 Å resolution. Cren7 kinks the dsDNA sharply similar to Sul7d, another chromatin protein existing only in Sulfolobales, which reveals that the “bending and unwinding” compacting mechanism is conserved in Crenarchaeota. Significant structural differences are revealed by comparing both protein–dsDNA complexes. The kinked sites on the same dsDNA in the complexes with Sul7d and Cren7 show one base pair shift. For Cren7, fewer charged residues in the β‐barrel structural region bind to DNA, and additionally, the flexible loop Lβ3β4 is also involved in the binding. Electrophoretic mobility shift assays indicate that loop Lβ3β4 is essential for DNA‐binding of Cren7. These differences provide insight into the functional difference of both chromatin proteins, suggesting that Cren7 may be more regulative than Sul7d in the DNA‐binding affinity by the methylation in the flexible loop Lβ3β4
in vivo.
Solution structure of the N‐terminal domain of DC‐UbP/UBTD2 and its interaction with ubiquitin
Authors: Song Ai‐Xin , Zhou Chen‐Jie , Guan Xiao , Sze Kong‐Hung , Hu Hong‐Yu
Published: March 2010

DC‐UbP/UBTD2 is a ubiquitin (Ub) domain‐containing protein first identified from dendritic cells, and is implicated in ubiquitination pathway. The solution structure and backbone dynamics of the C‐terminal Ub‐like (UbL) domain were elucidated in our previous work. To further understand the biological function of DC‐UbP, we then solved the solution structure of the N‐terminal domain of DC‐UbP (DC‐UbP_N) and studied its Ub binding properties by NMR techniques. The results show that DC‐UbP_N holds a novel structural fold and acts as a Ub‐binding domain (UBD) but with low affinity. This implies that the DC‐UbP protein, composing of a combination of both UbL and UBD domains, might play an important role in regulating protein ubiquitination and delivery of ubiquitinated substrates in eukaryotic cells.
Direct identification of the site of binding on the chaperone SecB for the amino terminus of the translocon motor SecA
Authors: Randall Linda L. , Henzl Michael T.
Published: March 2010

Protein export mediated by the general secretory Sec system in Escherichia coli proceeds by a dynamic transfer of a precursor polypeptide from the chaperone SecB to the SecA ATPase motor of the translocon and subsequently into and through the channel of the membrane‐embedded SecYEG heterotrimer. The complex between SecA and SecB is stabilized by several separate sites of contact. Here we have demonstrated directly an interaction between the N‐terminal residues 2 through 11 of SecA and the C‐terminal 13 residues of SecB by isothermal titration calorimetry and analytical sedimentation velocity centrifugation. We discuss the unusual binding properties of SecA and SecB in context of a model for transfer of the precursor along the pathway of export.
Beta‐2‐microglobulin expression correlates with high‐grade prostate cancer and specific defects in androgen signaling
Authors: Mink Sheldon R. , Hodge Amanda , Agus David B. , Jain Anjali , Gross Mitchell E.
Published: March 2010

BACKGROUND

Previously, we identified Beta‐2‐microglobulin (β2M) as an androgen‐regulated secreted protein elevated in the serum of prostate cancer patients. In this study, we explore an interaction between β2M expression, prostate cancer tissue, and the androgen signaling axis.

METHODS

β2M expression in relation to clinical and pathologic variables was examined in a tissue microarray representing specimens obtained at the time of radical prostatectomy. Viral vectors were designed to down‐regulate β2M expression, and the effects on androgen‐dependent growth, transcriptional regulation, and androgen receptor recruitment was investigated in human prostate cancer cell lines.

RESULTS

Variation in β2M expression in human prostate cancer is associated with characteristics of clinically aggressive disease such as high tumor grade. Knockdown of β2M expression in human prostate cancer cells resulted in selective defects in androgen‐dependent events including growth, gene regulation, and chromatin assembly.

CONCLUSIONS

β2M expression may provide prognostic information in patients treated with surgery for prostate cancer. Targeting β2M expression or activity may represent a new and important mechanism to manipulate the androgen signaling axis in patients with prostate cancer. Prostate 70: 1201–1210, 2010. © 2010 Wiley‐Liss, Inc.
Electrochemical preparation of MoO3 buffer layer deposited onto the anode in organic solar cells
Authors: Gacitua M. , Boutaleb Y. , Cattin L. , Abe S. Yapi , Lare Y. , Soto G. , Louarn G. , Morsli M , Rehamnia R. , del Valle M. A. , Drici A. , Bernède J. C.
Published: March 2010

In this work the authors have studied the advantages of using electrochemically deposited molybdenum oxide as a buffer layer in an organic bilayer heterojunction solar cell arrangement. Furthermore, it has been probed that electrochemistry provides an alternative low cost, reproducible and less laborious method to prepare thin layered deposits. The precursor solution is composed by a concentrated molybdic acid solution in a sulphuric media in order to ensure the obtainment of low reduced molybdenum species. Therefore, by means of potentiostatic techniques, ITO/molybdenum oxide transparent anodes were tested for the photovoltaic device showing improved surface properties. XDR and AFM techniques were used to characterize the morphology of the deposits. The films with optimum thickness (5 nm) are amorphous. XPS analysis indicates that the best results in solar cell performance are in hand with a heterogeneous composition of the molybdenum oxide film presenting MoV and MoVI as predominant species. The MoO3 films deposited by cyclic voltammetry are not as homogeneous as those deposited by potentiostatic technique and only MoVI species are present. These differences may justify the different behaviour of the solar cells using these different buffer layers. Only buffer layers deposited by potentiostatic technique allow improving the cells performances in the same way than those achieved by evaporation.
A MIP‐based biomimetic sensor for the impedimetric detection of histamine in different pH environments
Authors: Bongaers E. , Alenus J. , Horemans F. , Weustenraed A. , Lutsen L. , Vanderzande D. , Cleij T. J. , Troost F. J. , Brummer R.‐J. , Wagner P.
Published: March 2010

The development of novel biosensors is a rapidly growing field. Substituting the biological receptor layer from the biosensor with a synthetic receptor opens the door for the development of biomimetic sensors that are chemically and physically inert, as opposed to the sensors containing biological recognition elements. Using molecularly imprinted polymers (MIPs) the specificity and affinity of biological receptors can be mimicked. In addition, a MIP‐based sensor can measure in harsh environments. Histamine occurs in harsh environments in food and bodily fluids and is chosen as the target molecule for impedimetric detection. When 10 nM histamine is present in pH neutral environments, the impedance increases 45% with respect to the impedance of the sensor without histamine. Specificity is tested with respect to histidine. The influence of the pH on the performance of the sensor is tested. In a pH range of pH 5–12 the MIPs are stable, although they exhibit a varying degree of protonation. The same holds true for the target molecule of which the protonation also varies with the pH of the solution. It is shown that the pH dependent degree of protonation of both the MIP and the histamine has a large impact on the binding of histamine to the nanocavity in the MIP. Hence, the detection of histamine by a MIP‐based sensor is affected by the pH of the solution.
Gas sensor investigation based on a catalytically activated thin‐film thermopile for H2O2 detection
Authors: Kirchner Patrick , Ng Yue Ann , Spelthahn Heiko , Schneider Andreas , Henkel Hartmut , Friedrich Peter , Kolstad Jens , Berger Jörg , Keusgen Michael , Schöning Michael J.
Published: March 2010

In aseptic filling systems, hydrogen peroxide vapour is commonly used for the reduction of microbial contaminations in carton packages. In this process, the germicidal efficiency of the vapour depends especially on the H2O2 concentration. To monitor the H2O2 concentration, a calorimetric H2O2 gas sensor based on a catalytically activated thin‐film thermopile is investigated. Two different sensor layouts, namely a circular and a linear form, as well as two various material pairs such as tungsten/nickel and gold/nickel, have been examined for the realization of a thin‐film thermopile. Additionally, manganese oxide and palladium particles have been compared as responsive catalysts towards H2O2. The thin‐film sensors have been investigated at various H2O2 concentrations, gas temperatures and flow rates.
Co‐adsorption processes, kinetics and quantum mechanical modelling of nanofilm semiconductor gas sensors
Authors: Velasco‐Vélez Juan‐Jesús , Kunze Ulrich , Haas Thomas , Doll Theodor
Published: March 2010

A quantum mechanical model of co‐adsorption on semiconductor surfaces is developed and successfully adopted towards exposure to several gases. It is related to nanofilms and thus allows the application of electric fields altering the electronic surface properties of adsorption centres (electroadsorptive effect, EAE). The model is matched against experimental data with O2, NO2 and CO measurements under the hypothesis of no direct interaction among the species. However the sequence of adsorption plays an important role where the adsorption of one gas species is opening up other sites that are filled by another sort of impinging molecules. Quantum mechanical modelling of co‐adsorption: (a) NO2 and CO present at the SnO2 surface. (b) Simplified model. (c) Probability of adsorption.

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Finite element simulation of the optical modes of semiconductor lasers
Authors: Pomplun Jan , Burger Sven , Schmidt Frank , Schliwa Andrei , Bimberg Dieter , Pietrzak Agnieszka , Wenzel Hans , Erbert Götz
Published: March 2010

In the present paper we investigate optical near fields in semiconductor lasers. We perform finite element simulations for two different laser types, namely a super large optical waveguide (SLOW) laser, which is an edge emitter, and a vertical cavity surface emitting laser (VCSEL). We give the mathematical formulation of the different eigenvalue problems that arise for our examples and explain their numerical solution with the finite element method (FEM). Thereby, we also comment on the usage of transparent boundary conditions, which have to be applied to respect the exterior environment, e.g., the very large substrate and surrounding air. For the SLOW laser we compare the computed near fields to experimental data for different design parameters of the device. For the VCSEL example a comparison to simplified 1D mode calculations is carried out.
Pre‐requisites for the formation of unusual diffusion profiles in II–VI semiconductors
Authors: Wolf H. , Kronenberg J. , Wagner F. , Wichert Th.
Published: March 2010

The diffusion of the impurities Cu, Ag, Au, and Na in CdTe and CdZnTe exhibits the unusual phenomenon of uphill diffusion if the diffusion of the impurity is performed under external Cd pressure at temperatures typically in the range 700–900 K. A model is proposed that describes these concentration profiles quantitatively and yields pre‐requisites for the observation of uphill diffusion. If a metal layer is evaporated onto the implanted surface, the diffusion of the impurity is strongly affected by the generation of intrinsic defects at the metal–semiconductor interface.
Density‐functional study on the migration of Cd and Te adsorbates on the (001) surface of CdTe
Authors: Patrakov Anatoly E. , Fink Reinhold F. , Fink Karin , Schmidt Thomas C. , Engels Bernd
Published: March 2010

We present a density‐functional study on the mobility of cadmium (Cd) and tellurium (Te) adsorbate atoms on the reconstructed Te‐terminated (001) CdTe (2 × 1) surface. Two‐dimensional potential energy surfaces as a function of the position of the adsorbate atom on the surface were calculated. For Cd as well as Te adsorption, two potential minima were found. The binding energies amount to −2. and −0.71 eV for Cd (−2.8 and −1.4 eV for Te). At any position of the surface, Te adsorption is found to be stronger than that of Cd. Our results indicate that an adsorption of a Te atom at the reconstructed Te‐terminated (001) CdTe (2 × 1) surface leads to adsorbates which may move along the surface due to their thermal energy. In the opposite, Cd adsorbate atoms are essentially trapped in the global minimum and desorption is expected to be much more likely than motion along the surface.
On the solution‐space geometry of random constraint satisfaction problems
Authors: Achlioptas Dimitris , Coja‐Oghlan Amin , Ricci‐Tersenghi Federico
Published: March 2010

For various random constraint satisfaction problems there is a significant gap between the largest constraint density for which solutions exist and the largest density for which any polynomial time algorithm is known to find solutions. Examples of this phenomenon include random k‐SAT, random graph coloring, and a number of other random constraint satisfaction problems. To understand this gap, we study the structure of the solution space of random k‐SAT (i.e., the set of all satisfying assignments viewed as a subgraph of the Hamming cube). We prove that for densities well below the satisfiability threshold, the solution space decomposes into an exponential number of connected components and give quantitative bounds for the diameter, volume, and number.© 2010 Wiley Periodicals, Inc. Random Struct. Alg., 38, 251–268, 2011
Eco‐clothing, consumer identity and ideology
Authors: Niinimäki Kirsi
Published: March 2010

This paper aims to contribute to a better understanding of eco‐fashion consumption and consumer purchase decisions while constructing one's self with external symbols, such as appearance, clothing and fashion items. This study approaches sustainable clothing from a grounding in design research and the meanings of material culture. The study uses sociology and social psychology; hence, the meaning of appearance and especially clothing and fashion is understood in a social context. This paper also takes an interdisciplinary approach to eco‐clothes as cultural and design objects in a social and sustainable development context, objects that intertwine consumers' ethical attitudes and values and how they construct a concept of ‘self’ using external symbols. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
Molecular depth profiling of polymers with very low energy reactive ions
Authors: Houssiau L. , Mine N.
Published: March 2010

This work follows previous studies in which we demonstrated the feasibility of molecular depth profiling with time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), using a low‐energy Cs+ source for sputtering. Poly(methyl methacrylate) (PMMA), polycarbonate (PC) and polystyrene (PS) thin films were investigated with both 250 eV Cs+ and Xe+ ions with the aim of assessing the role of the ion's reactivity in polymer depth profiling. A more detailed analysis of PS layers was given, completed with X‐ray photoelectron spectroscopy (XPS) measurements, since this polymer is known to degrade rapidly under ion irradiation. Indeed, no depth profile is possible on PS with conventional polyatomic sources. The three polymers were amenable to depth profiling with low‐energy Cs+. On the other hand, they were quickly degraded by the low‐energy Xe+ beam, although some specific molecular ions remained detectable throughout the depth profile on PMMA. Sputtering yield measurements provided valuable information on the chemistry involved during the sputtering process: the sputtering yields measured on PMMA, with both Cs+ and Xe+, were much higher than on PC and PS, probably due to depolymerization processes. On PC and PS, the sputtering yield was much higher with Cs+ than with Xe+. This is due to an inhibition of the cross‐linking reactions by the implanted Cs atoms, leading to the formation of caesium carbides and anions. Low‐energy caesium depth profiling is successful, thanks to the combination of three factors: (i) low energy means less damage; (ii) Cs enhances the negative ionization; and (iii) the Cs reactivity hinders cross‐linking reactions. Copyright © 2010 John Wiley & Sons, Ltd.
The potential for the application of X‐ray photoelectron spectroscopy in forensic science
Authors: Watts John F.
Published: March 2010

The potential for the use of X‐ray photoelectron spectroscopy (XPS) in forensic science is reviewed. Taking as a starting point a series of examples and case histories, this review speculates on other areas where XPS may be able to make a contribution. The topics that are considered include chemical speciation of fingerprints, thin layers deposited on substrates as a result of explosions and/or fire, particulate materials and cosmetics and finally sequestration of marker elements and molecules on surfaces. It is concluded that XPS has much to offer the forensic science community, but investigations may be hampered by the need to compare specimens from crime scene with known standards. Until this issue is addressed, it is likely that XPS will continue to be used on an ad hoc basis for particularly challenging specimens in high‐profile cases. Copyright © 2010 John Wiley & Sons, Ltd.
Application of the XPS for Studying the Magnetic Moment of 3d Metals in Carbon–Metal Nanostructures
Authors: Shabanova I. N. , Terebova N. S.
Published: March 2010

A promising trend in the development of methods for studying the electronic structure of a substance is using the methods based on the application of X‐ray photoelectron spectroscopy (XPS).

In the present article, the change of the spin magnetic moment of the transition 3d metal atoms is studied in metal‐containing nanoscale structures based on the relationship between the spin magnetic moment and the ratio of the intensities of multiplet splitting maxima in 3s spectra of metals. Copyright © 2010 John Wiley & Sons, Ltd.
Structure and properties of nitrogen‐doped titanium dioxide thin films produced by reactive magnetron sputtering
Authors: Abadias G. , Paumier F. , Eyidi D. , Guérin P. , Girardeau T.
Published: March 2010

In modern purification techniques employing semiconductor‐mediated photo oxidation of toxic substances, TiO2 materials are the most widely used metal oxides due to their unique blend of properties. However, the band edge of these semiconductors lying in the ultraviolet (UV) region makes them rather inactive under visible light irradiation. Nitrogen‐doped titanium dioxide (N‐TiO2) is attracting a continuous attention because this doping generates states just above the valence band and consequently narrows the band gap of TiO2. The visible light activity of these materials mainly depends on the location of this impurity state and consequently on the microstructure of the (N‐TiO2) materials. The objective of this study is to investigate the correlations between the microstructure of these materials and their electronic and optical properties. The N‐TiO2 films have been produced by reactive magnetron sputtering of a titanium target under a mixture of argon, nitrogen and oxygen gases. The microstructure and chemical properties of the films have been investigated by X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). Ellipsometry and reflection electron energy loss spectroscopy (REELS)have been used to study their electronic and optical properties. The influence of a post‐annealing at 550 °C on these different properties has been also investigated. Copyright © 2010 John Wiley & Sons, Ltd.
Oxide‐film growth kinetics on Zr(0001) and Zr(1010) single‐crystal surfaces
Authors: Bakradze Georgijs , Jeurgens Lars P. H. , Mittemeijer Eric J.
Published: March 2010

The growth kinetics of very thin (<10 nm) oxide films on Zr(0001) and Zr(1010) single‐crystalline surfaces was investigated by real‐time in situ spectroscopic ellipsometry (RISE). To this end, clean Zr(0001) and Zr(1010) surfaces were prepared under ultrahigh vacuum conditions by a cyclic treatment of ion sputtering and in vacuo annealing. The thus obtained bare Zr surfaces were subsequently exposed to O2 (g) in the temperature range of 300–450 K (at a partial oxygen pressure of 10−4 Pa) while monitoring the growth kinetics by RISE. Quantitative RISE analysis showed that the less densely packed Zr(1010) surface oxidizes more readily than the densely packed Zr(0001) surface. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of oxygen plasma on surface properties and biocompatibility of PLGA films
Authors: Hasirci Nesrin , Endogan Tugba , Vardar Elif , Kiziltay Aysel , Hasirci Vasif
Published: March 2010

In this study, poly(D, L‐lactide‐co‐glycolide) (PLGA) films were prepared by solvent casting method and the surfaces of the films were modified by application of oxygen plasma. A radio frequency (RF) generator working at 13.56 MHz was used to create plasma, and powers at different levels changing between 20 and 300 W were applied. The variations in chemistry, topography and surface free energy (SFE) of the films were investigated by electron spectroscopy for chemical analysis (ESCA), atomic force microscopy (AFM) and goniometer, respectively. The cell–material interactions of the modified samples were evaluated by cell culture tests using 3T3 fibroblast cell line.

As the applied power of the RF generator was increased from 20 to 300 W, the surface oxygen content (examined by ESCA) first increased up to 100 W, and then decreased mostly because of crosslink formation by elimination of oxygen. Surface roughness (examined by AFM) and hydrophilicity (examined by water contact angle measurements) increased parallel to the applied power. SFE and the basic component of SFE also increased while the acidic component did not show a significant change with power according to the geometric mean approach. In vitro material–cell interaction studies showed that oxygen plasma modification enhanced the cell attachment and cell proliferation on PLGA samples. Copyright © 2010 John Wiley & Sons, Ltd.
Surface analysis of SiO2‐like high‐barrier thin films for protection of silver artefacts
Authors: Angelini E. , Grassini S. , Ingo G. M. , Mombello D. , Fracassi F. , Palumbo F.
Published: March 2010

Surface engineering has been explored using plasma enhanced chemical vapur deposition (PECVD) of SiO2‐like coatings on different metallic substrates in order to improve their resistance to corrosion. Specifically, the coatings have been deposited onto silver‐based alloys which are prone to unaesthetic tarnishing, by means of PECVD in radio frequency (RF) plasma fed with tetraetoxysilane/oxygen/argon mixture.

Microchemical and microstructural characterization of the coatings has been carried out by means of X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The protective effectiveness against tarnishing of SiO2‐like layers has been evaluated by immersion tests in 0.1 M Na2S aerated solution at room temperature.

It has been found that SiO2‐like coatings deposited by increasing the oxygen‐to‐monomer ratio in the feeding‐gas mixture and the input power density possess excellent barrier effects, and the coating adhesion increases if the deposition process is performed after a hydrogen plasma treatment. The protective effectiveness of PECVD coatings may be related to their barrier effect against the diffusion of water and other gaseous aggressive agents present in the environment and coming into contact with the metal surface. Copyright © 2010 John Wiley & Sons, Ltd.