bluuebunny/crossref_metadata_2025 huggingface dataset:
PML absorbing boundary conditions for the linearized and nonlinear Euler equations in the case of oblique mean flow
Authors: Parrish Sarah A. , Hu Fang Q.
Published: September 2008

For the case of uniform mean flow in an arbitrary direction, perfectly matched layer (PML) absorbing boundary conditions are presented for both the linearized and nonlinear Euler equations. Although linear perfectly matched side layers with an oblique mean flow have been studied in previous works, we propose in the present paper a construction of corner layer equations that are dynamically stable. Stability issues are investigated by examining the dispersion relations of linear waves supported by the corner layer equations. For increased efficiency, a pseudo mean flow is included in the derivation of the PML equations for the nonlinear case. Numerical examples are given to support the validity of the proposed equations. Specifically, the linear PML formulation is tested for the case of acoustic, vorticity, and entropy waves traveling with an oblique mean flow. The nonlinear formulation is tested with an isentropic vortex moving diagonally with a constant velocity. Copyright © 2008 John Wiley & Sons, Ltd.
Lattice Boltzmann method for flows in porous and homogenous fluid domains coupled at the interface by stress jump
Authors: Bai Huixing , Yu P. , Winoto S. H. , Low H. T.
Published: September 2008

A numerical method was developed for flows involving an interface between a homogenous fluid and a porous medium. The numerical method is based on the lattice Boltzmann method for incompressible flow. A generalized model, which includes Brinkman term, Forcheimmer term and nonlinear convective term, was used to govern the flow in the porous medium region. At the interface, a shear stress jump that includes the inertial effect was imposed for the lattice Boltzmann equation, together with a continuity of normal stress. The present method was implemented on three cases each of which has a porous medium partially occupying the flow region: channel flow, plug flow and lid‐driven cavity flow. The present results agree well with the analytical and/or the finite‐volume solutions. Copyright © 2008 John Wiley & Sons, Ltd.
A new interface‐capturing discretization scheme for numerical solution of the volume fraction equation in two‐phase flows
Authors: Walters D. Keith , Wolgemuth Nicole M.
Published: September 2008

A new high‐resolution spatial discretization scheme for use with the interface‐capturing volume‐of‐fluid method is presented and applied to several test cases. The new scheme is intended to preserve the volume fraction discontinuity without the need to explicitly reconstruct the interface within computational control volumes near the interface. The method is based on maximization of the volume fraction gradient in the region of the interface, while stability is preserved by maintaining net upwind biasing of the face flux prescription in each computational control volume. In addition, the scheme employs face limiting to satisfy boundedness criteria at finite‐volume control surfaces (faces) and prevent variable overshoot. The method has been developed for use with unstructured, anisotropic, and/or inhomogeneous meshes that are often used for simulation of geometrically complex flow fields. This paper presents the implementation of the new discretization scheme into a steady‐state solver in order to isolate the spatial discretization from the time integration technique. The new scheme is validated for steady‐state two‐phase flow using several test cases, and is shown to preserve the phase interface almost exactly, with essentially zero dissipative or dispersive error in the volume fraction solution. Copyright © 2008 John Wiley & Sons, Ltd.
P2Y1receptor signaling enhances neuroprotection by astrocytes against oxidative stress via IL‐6 release in hippocampal cultures
Authors: Fujita Takumi , Tozaki‐Saitoh Hidetoshi , Inoue Kazuhide
Published: September 2008

Cell survival is a critical issue in the onset and progression of neurodegenerative diseases and following pathological events including ischemia and traumatic brain injury. Oxidative stress is the main cause of cell damage in such pathological conditions. Here, we report that adenosine 5′‐triphosphate (ATP) protects hippocampal astrocytes from hydrogen peroxide (H2O2)‐evoked oxidative injury in astrocyte monocultures. The effect of ATP was prevented by a selective antagonist of or siRNAs against P2Y1R. Interestingly, in astrocyte‐neuron cocultures, ATP also produced neuroprotective effects against H2O2‐evoked neuronal cell death, whereas ATP did not produce any neuroprotective effects in monocultures. The ATP‐induced neuroprotection in cocultures was completely inhibited by silencing of astrocytic P2Y1R expression, indicating that ATP acts on astrocytes and enhances their neuroprotective functions by activating P2Y1R. Furthermore, this neuroprotective effect was mimicked by applying conditioned medium from astrocytes that had been stimulated by ATP, implying an involvement of diffusible factors from astrocytes. We found that, in both purified astrocyte cultures and astrocyte‐neuronal cocultures, ATP and the P2Y1R agonist 2‐methylthioadenosine 5′ diphosphate (2MeSADP) induced the release of interleukin‐6 (IL‐6), but this did not occur in neuron monocultures. Moreover, exogenous IL‐6 produced a neuroprotective effect, and the neuroprotection induced by P2Y1R‐stimulated astrocytes was prevented in the presence of an anti‐IL‐6 antibody. Taken together, these results suggest that P2Y1R‐stimulated astrocytes protect against neuronal damage induced by oxidative stress, and that IL‐6 is a crucial signaling molecule released from astrocytes. Thus, activation of P2Y1R in astrocytes may rescue neurons from secondary cell death under pathological conditions. © 2008 Wiley‐Liss, Inc.
Potent in vitro and in vivo antitumor activity of interleukin‐4‐conjugated Pseudomonas exotoxin against human biliary tract carcinoma
Authors: Ishige Kazunori , Shoda Junichi , Kawamoto Toru , Matsuda Sachiko , Ueda Tetsuya , Hyodo Ichinosuke , Ohkohchi Nobuhiro , Puri Raj K. , Kawakami Koji
Published: September 2008

Targeting cytotoxins or immunotoxins to tumor cell surface receptors represents a new approach for the treatment of cancers. We tested the antitumor activity of a cytotoxin (IL‐4‐PE) composed of an interleukin‐4 (IL‐4) targeting moiety and a truncated form of Pseudomonas exotoxin A against human biliary tract carcinoma (BTC). Immunohistochemical analysis showed that cultured BTC cell lines and cancerous epithelia in BTC tissue (e.g., gallbladder carcinoma, extraheaptic cholangiocarcinoma, and intrahepatic cholangiocarcinoma) expressed receptors for IL‐4 in situ at high densities. However, normal epithelial cells in gallbladder and bile duct tissues did not express these IL‐4 receptors. Eight BTC cell lines expressed IL‐4R on the cell surface as determined by radiolabeled ligand binding assays. When these cells were treated with IL‐4‐PE, significant cytotoxicity was observed as determined by the inhibition of protein synthesis. The concentration of agent causing 50% inhibition of protein synthesis (IC50) was found to be less than 10 ng/mL in 4 of the 8 BTC cell lines studied. The antitumor activity of IL‐4‐PE was assessed for human BTC cells implanted subcutaneously in immunodeficient mice. By intratumoral injection of IL‐4‐PE, complete disappearance of the established tumors was observed in 40% of animals. Intraperitoneal administration of IL‐4‐PE at tolerated doses to animals with peritoneally disseminated BTC exhibited significantly prolonged survival compared to untreated animals (>14 weeks vs. 5 weeks in treated and untreated mice, respectively). These results indicate that IL‐4 receptor‐targeted cytotoxin is a potent agent that may provide a new therapeutic option for BTC. © 2008 Wiley‐Liss, Inc.
Identification of an invasion and tumor‐suppressing gene, Endoglin (ENG), silenced by both epigenetic inactivation and allelic loss in esophageal squamous cell carcinoma
Authors: Wong Victor Chun Lam , Chan Pui Ling , Bernabeu Carmelo , Law Simon , Wang Li Dong , Li Ji‐Lin , Tsao Sai Wah , Srivastava Gopesh , Lung Maria Li
Published: September 2008

Endoglin (ENG) has been identified as a candidate tumor‐suppressor gene in esophageal squamous cell carcinoma (ESCC). Earlier microcell‐mediated chromosome transfer (MMCT) studies of chromosome 9 in ESCC narrowed down a tumor‐suppressive critical region to 9q33‐34. ENG maps to 9q34‐qter and encodes a transformation growth factor beta (TGFβ) superfamily auxiliary receptor. This study aims to identify the potential role for ENG in ESCC development. Significant downregulation of ENG was detected at frequencies of 87.5% in 16 ESCC cell lines, 39.1% directly in 23 ESCC tumor specimens from Hong Kong, and 33.4% in 18 ESCC tumor specimens from the high‐risk ESCC region of Henan, China. By methylation‐specific PCR, methylated sequences were detected in an ESCC cell line panel and in clinical specimens. Following demethylation treatment in 9 ESCC cell lines, ENG expression was obviously restored. Loss of heterozygosity (LOH) in a 4.7 Mb region on 9q32‐q34, where ENG maps, was observed directly in ESCC tumor tissues. Both epigenetic methylation and allelic loss appear to contribute to ENG downregulation in tumor cells. In vitro and in vivo functional studies such as colony formation, Matrigel culture, invasion and tumorigenicity assays were performed. Colony formation efficiency was significantly reduced by overexpression of ENG. In addition, significantly smaller colonies of ENG stable transfectants were formed in Matrigel culture. Significant suppression of invasion efficiency and tumorigenicity were also observed, when comparing the ENG stable transfectants with the vector‐alone transfectants. This study provides evidence supporting ENG, as a cell invasion and tumor‐suppressing gene in ESCC. © 2008 Wiley‐Liss, Inc.
Quantitative monitoring of cyclin D1 expression: A molecular marker for minimal residual disease monitoring and a predictor of the disease outcome in patients with mantle cell lymphoma
Authors: Brizova Helena , Kalinova Marketa , Krskova Lenka , Mrhalova Marcela , Kodet Roman
Published: September 2008

In mantle cell lymphoma (MCL), minimal residual disease (MRD) is an indicator of the disease outcome. Quantitative methods used so far do not provide a suitable molecular marker in 30–70% patients with MCL (depending on the technique used). We tested cyclin D1 as a marker for quantitative MRD monitoring. The real‐time PCR of cyclin D1 mRNA was performed in 144 bone marrow (BM) specimens including 95 BMs from MCL patients, 39 BMs from patients with other B‐cell non‐Hodgkin's lymphomas and 10 BMs from healthy volunteer donors. In 73 BMs obtained from 20 MCL patients we examined the cyclin D1 level during the treatment and follow‐up period. We detected a cyclin D1 overexpression exclusively in BMs infiltrated with MCL, including minimal residual infiltration. Dynamics of cyclin D1 correlated with the patient's clinical status in 69/73 BMs. Individual monitoring of patients during the disease course showed cyclin D1 quantitative changes accompanying either the disease relapse or a successful treatment response or the disease‐free survival (remission) and it showed a predictive significance. Cyclin D1 detection is a promising approach for the quantitative MRD monitoring in MCL patients, and the individual monitoring of the cyclin D1 dynamics represents a suitable indicator of the disease course. © 2008 Wiley‐Liss, Inc.
The C‐terminus of apoptin represents a unique tumor cell‐enhanced nuclear targeting module
Authors: Kuusisto Henna V. , Wagstaff Kylie M. , Alvisi Gualtiero , Jans David A.
Published: September 2008

Chicken anemia virus viral protein 3 (VP3 or apoptin) localizes more efficiently in the nucleus of transformed than nontransformed cells. Although previous studies implicate the C‐terminus of apoptin as being responsible, the molecular basis is controversial, and the extent to which altered nuclear transport efficiency in tumor cells may influence VP3 differential targeting unclear. Here we establish that the C‐terminus of VP3 (residues 74–121), out of the context of the full‐length protein, is indeed sufficient for tumor cell‐enhanced nuclear targeting through phosphoinhibition of VP3 (74–121)‐mediated nuclear export occurring exclusively in tumor cells. Importantly, we show that VP3 (74–121) is unique in showing tumor cell‐enhanced nuclear targeting in that other NLS‐containing proteins fail to show differential localization in human osteosarcoma cells compared to their normal isogenic counterparts. Thus, the C‐terminus of VP3 represents a unique tumor cell‐enhanced nuclear targeting module with potential application in tumor cell‐specific drug delivery. © 2008 Wiley‐Liss, Inc.
Glycine transporters and synaptic function
Authors: Zafra Francisco , Giménez Cecilio
Published: September 2008

Glycine is an inhibitory neurotransmitter that is mainly active in the caudal areas of the CNS. However, glycine also participates in excitatory neurotransmission since it is a co‐agonist of the NMDA subtype of glutamate receptors. The concentration of glycine at synapses is mainly controlled by two sodium and chloride dependent transporters, GLYT1 and GLYT2, proteins that display a complementary distribution and activity in the nervous system. Our understanding of the physiological role of these transporters has advanced recently, thanks to the development of specific inhibitors and the generation of mice defective in the corresponding genes. In addition, the three‐dimensional resolution of the structure of a bacterial homologue has shed light on the mechanisms of glycine transport. It is likely that this knowledge will prove to be useful for the development of drugs with antipsychotic, procognitive or analgesic properties. © 2008 IUBMB IUBMB Life, 60(12): 810–817, 2008
Retention of mechanical properties and cytocompatibility of a phosphate‐based glass fiber/polylactic acid composite
Authors: Ahmed I. , Cronin P. S. , Abou Neel E. A. , Parsons A. J. , Knowles J. C. , Rudd C. D.
Published: September 2008

Polymers prepared from polylactic acid (PLA) have found a multitude of uses as medical devices. The main advantage of having a material that degrades is so that an implant would not necessitate a second surgical event for removal. In addition, the biodegradation may offer other advantages. In this study, fibers produced from a quaternary phosphate‐based glass (PBG) in the system 50P2O5‐40CaO‐5Na2O‐5Fe2O3 (nontreated and heat‐treated) were used to reinforce the biodegradable polymer, PLA. Fiber properties were investigated, along with the mechanical and degradation properties and cytocompatibility of the composites produced. Retention of mechanical properties overtime was also evaluated. The mean fiber strength for the phosphate glass fibers was 456 MPa with a modulus value of 51.5 GPa. Weibull analysis revealed a shape and scale parameter value of 3.37 and 508, respectively. The flexural strength of the composites matched that for cortical bone; however, the modulus values were lower than those required for cortical bone. After 6 weeks of degradation in deionized water, 50% of the strength values obtained was maintained. The composite degradation properties revealed a 14% mass loss for the nontreated and a 10% mass loss for the heat‐treated fiber composites. It was also seen that by heat‐treating the fibers, chemical and physical degradation occurred much slower. The pH profiles also revealed that nontreated fibers degraded quicker, thus correlating well with the degradation profiles. The in vitro cell culture experiments revealed both PLA (alone) and the heat‐treated fiber composites maintained higher cell viability as compared to the nontreated fiber composites. This was attributed to the slower degradation release profiles of the heat‐treated composites as compared to the nontreated fiber composites. SEM analyses revealed a porous structure after degradation, and it is clear that there are possibilities here to tailor the distribution of porosity within polymer matrices. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Evaluation of polyaromatic hydrocarbon removal from aqueous solutions using activated carbon and hyper‐crosslinked polymer (Macronet MN200)
Authors: Valderrama César , Gamisans Xavier , Cortina Jose L , Farrán Adriana , de las Heras F Xavier
Published: September 2008

BACKGROUND: Sorption of polycyclic aromatic hydrocarbons (PAHs) on activated carbon and the Macronet polymeric sorbent MN200 was investigated to determine the effectiveness of each sorbent for removal of pollutants from aqueous solution and their possible use as sorbent materials for groundwater. Experiments were carried out to determine the loading capacities of a family of PAHs (acenaphthene, anthracene, fluoranthene, fluorene, naphthalene and pyrene).

RESULTS: Activated carbon was the more effective sorbent, with maximum loadings of PAHs between 90 and 230 g kg−1, while MN200 resin showed values of 25–160 g kg−1. Loading isotherms based on the Langmuir, Freundlich and Redlich–Peterson models were determined. The hydrophobic character of the pollutants appeared as an important parameter related to the sorption process. Equilibrium and kinetic parameters were used to determine the retardation factors for each PAH.

CONCLUSION: The calculated values for the simulation of barrier thickness using both sorbents, taking into account EU requirements for PAHs in groundwater effluent, were perfectly reasonable as a first estimate. The better kinetic properties of MN200 are evident in lower hydraulic residence times and consequently in a lower barrier thickness. Copyright © 2008 Society of Chemical Industry
Sample preparation for the quick sizing of metal nanoparticles by atomic force microscopy
Authors: Vinelli Alessandra , Primiceri Elisabetta , Brucale Marco , Zuccheri Giampaolo , Rinaldi Ross , Samorì Bruno
Published: September 2008

Two alternative pretreatment methods for depositing metal nanoparticles on mica for atomic force microscopy (AFM) imaging are presented. The treated substrates are flat and clean, thus they are amenable of use to characterize very small nanoparticles. The methods do not require any instrumentation or particular expertise. As they are also very quick, the need for storage of the prepared substrates is avoided altogether. These proposed methods, which are compared with the results of transmission electron microscopy analysis, allow the quick sizing and characterization of nanoparticles with the atomic force microscope and could thus help expanding the user community of nanoparticle researchers who could use the AFM for their characterization needs. Microsc. Res. Tech., 2008. © 2008 Wiley‐Liss, Inc.
Evolution of the shell coat and yolk in amniotes: a marsupial perspective
Authors: Menkhorst Ellen , Nation Angela , Cui Shuliang , Selwood Lynne
Published: September 2008

Two characters distinguish oogenesis and early development in marsupials and monotremes: (1) the shell coat that persists from the zygote to somite stages in marsupials or until hatching in monotremes; and (2) the numerous, apparently almost empty vesicles that appear in primary oocytes, increase during oogenesis in marsupials and monotremes before being shed into the cleavage cavity and are preferentially distributed to the trophoblast lineage in marsupials, but comprise the latebra in monotremes. Analysis of these unusual characters used Southern analysis of genomic DNA dot blots and histology and electron microscopy. The evidence suggests that the marsupial shell coat protein, CP4, was probably characteristic of the egg of the mammalian ancestor. Further, the vesicles, present in marsupials during oogensis and cleavage and in eutherian mammals during blastocyst formation are the residual elements of white yolk present in the larger yolky eggs of monotemes and sauropsids. By comparison with the function of the vesicle components in marsupials, it is suggested that one role for the white yolk in monotremes and the sauropsids is to provide extracellular matrix (ECM), especially hyaluronan containing stabilizing proteins, for epithelial construction. Thus, as oviparity was replaced by viviparity, egg size was reduced, the germinal cytoplasm was retained, and yellow yolk was markedly reduced or lost in marsupials and eutherians. The white yolk was retained in monotremes and marsupials where blastocyst epithelial construction requires ECM support, and its appearance is heterochronously shifted to after compaction, when blastocyst formation and expansion occurs, in eutherian mammals. J. Exp. Zool. (Mol. Dev. Evol.) 312B:625–638, 2009. © 2008 Wiley‐Liss, Inc.
A survey of water‐extractable arabinopolymers in bread and durum wheat and the effect of water‐extractable arabinoxylan on durum dough rheology and spaghetti cooking quality
Authors: Turner Matthew A , Soh Cindy HN , Ganguli Nishath K , Sissons Mike J
Published: September 2008

BACKGROUND: Information on the variation in water‐extractable arabinopolymers (WEAP) in durum wheat and their impact on pasta quality is limited. A survey of the content of WEAP in selected bread wheat varieties and durum wheat was conducted and the influence of water‐extractable arabinoxylans (WEAX) on dough and spaghetti quality was examined by fortifying low‐WEAP durum semolina with purified WEAX.

RESULTS: Bread wheat typically possessed higher levels of WEAP than durum wheat, but the latter had a greater range. Purified WEAX was extracted from bread wheat cultivar Sunlin which possessed a high level of WEAP. The extract was used to fortify semolina (0.125–2% w/w) derived from durum wheat variety Tamaroi (low WEAP). Fortification caused a near linear increase in farinograph water absorption of approximately 12% over the range of addition, leading to dough weakening. Reduced cooked pasta stickiness was observed at all levels of WEAX addition.

CONCLUSION: Increased WEAX content may be a means to improve pasta quality by reducing pasta stickiness. Durum wheat showed a wide range of WEAP contents, and this may well be exploited by developing cultivars with elevated WEAP levels. © 2008 Crown in the Right of the State of New South Wales and Society of Chemical Industry.
PrLZ expression is associated with the progression of prostate cancer LNCaP cells
Authors: Li Lei , Zhang Dong , Zhang Linlin , Zhu Guodong , Sun Yi , Wu Kaijie , Wang Xinyang , He Dalin
Published: September 2008

PrLZ is a novel recent isolated gene and specific expression in prostate tissues. PrLZ expression was specifically elevated in prostate embryonic tissues and androgen independent prostate cancer cells, suggesting it might be association with the embryonic development and malignancy progression. However, the function and mechanism of PrLZ during the progression of prostate cancer remain blurred. Our present studies showed PrLZ expression might enhance the proliferation and invasion capability in vitro and also increase the tumorigenicity in situ prostate cancer animal model, which is indicated PrLZ expression contributed to the malignancy progression of prostate cancer. In addition, PrLZ also might up regulate androgen receptor (AR) expression and increase the PSA expression, a putative downstream target gene of AR, which indicated PrLZ mediated the malignancy progression of prostate cancer was associated with androgen signals. © 2008 Wiley‐Liss, Inc.
A phenomenon of waiting time in phase change problems driven by radiative heat transfer
Authors: Fasano A. , Mancini A.
Published: September 2008

In the paper (J. Food Process Eng. 2008; in press) we emphasized that during a phase change process in which the heat input is driven by a radiation transfer mechanism, a peculiar phenomenon may occur, characterized by a temporary stop of the increase of the boundary temperature due to a sudden change of the heat transfer coefficient upon phase transition. This time interval is needed to allow the thermal properties of the surface to evolve toward a state that is compatible with the heat intake rate corresponding to the new phase.

The occurrence of the waiting time is motivated and studied for a general one‐dimensional Stefan problem. Then an application is presented to the much complicated problem considered in (J. Food Process Eng. 2008; in press), namely, the model for frying process. Copyright © 2008 John Wiley & Sons, Ltd.
Multistep correlations via covariance processing of COSY/GCOSY spectra: opportunities and artifacts
Authors: Martin Gary E. , Hilton Bruce D. , Blinov Kirill A. , Williams Antony J.
Published: September 2008

Long‐range homonuclear coupling pathways can be observed in COSY or GCOSY spectra by the acquisition of spectra with larger numbers of increments of the evolution period, t1, than would normally be used. Alternatively, covariance processing of COSY‐type spectra acquired with modest numbers of t1 increments, allows the observation of multistage correlations. In this work results obtained from covariance‐processed GCOSY spectra are fully analyzed and compared to normally processed COSY and 80 ms TOCSY spectra. Multistage or ‘RCOSY‐type’ correlations are observed when remote protons both exhibit correlations to the same coupling partner e.g. A → B and B → C gives rise to an A → C correlation. In the strict sense, RCOSY‐type responses are artifacts albeit providing useful information. Nonbeneficial artifact correlations are observed when protons couple to other protons that overlap or partially overlap. The origin of artifact responses is also analyzed. Copyright © 2008 John Wiley & Sons, Ltd.
Structure elucidation and NMR spectral assignment of five new xanthones from the bark of Garcinia xanthochymus
Authors: Chen Yu , Zhong Fangfang , He Hongwu , Hu Yun , Zhu Dan , Yang Guangzhong
Published: September 2008

Five new xanthones, namely Garcinexanthones A–E (1–5), were isolated from the barks of Garcinia xanthochymus. Their structures were elucidated by spectral analysis, primarily NMR, MS, and UV. The complete assignments of the 1H NMR and 13C NMR chemical shifts for the compounds were achieved by using 1D and 2D NMR techniques, including DEPT, HSQC, and HMBC NMR experiments. Copyright © 2008 John Wiley & Sons, Ltd.
Inclusion complexes of cryptophane–E with dichloromethane and chloroform: A thermodynamic and kinetic study using the 1D‐EXSY NMR method
Authors: Aski Sahar Nikkhou , Takacs Zoltan , Kowalewski Jozef
Published: September 2008

Complexation equilibria and kinetics of exchange of chloroform and dichloromethane molecules between the cavity of cryptophane‐E and bulk solution were investigated using NMR methods. Using one‐dimensional magnetization transfer (1D‐EXSY type sequence), chemical exchange rates were measured in different temperature ranges, limited by the equilibrium constant values of the complexes and the boiling points of the guest substances. From the kinetic data, activation energies were calculated using the Arrhenius equation. From the temperature‐dependence of the association constant data, the enthalpy and entropy of complexation were estimated and compared with values for similar complexes of other cryptophanes. Copyright © 2008 John Wiley & Sons, Ltd.
A fourth‐order method for numerical integration of age‐ and size‐structured population models
Authors: Iannelli Mimmo , Kostova Tanya , Milner Fabio Augusto
Published: September 2008

In many applications of age‐ and size‐structured population models, there is an interest in obtaining good approximations of total population numbers rather than of their densities. Therefore, it is reasonable in such cases to solve numerically not the PDE model equations themselves, but rather their integral equivalents. For this purpose quadrature formulae are used in place of the integrals. Because quadratures can be designed with any order of accuracy, one can obtain numerical approximations of the solutions with very fast convergence. In this article, we present a general framework and a specific example of a fourth‐order method based on composite Newton‐Cotes quadratures for a size‐structured population model. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Epidemiology and clinical risk factors predisposing to thromboembolism in children with cancer
Authors: Athale Uma , Siciliano Sabrina , Thabane Lehana , Pai Nikhil , Cox Stephanie , Lathia Anita , Khan Anees , Armstrong Ankelly , Chan Anthony K.C.
Published: September 2008

Purpose

The prevalence and risk factors for thromboembolism (TE) in children with cancer are largely unknown. This retrospective cohort study aims to determine the epidemiology of TE and to identify potential risk factors for TE in children with cancer.

Methods

We used logistic regression to determine the association of age (<10 years vs. ≥10 years), gender, type of cancer, presence or absence of intra‐thoracic disease (mediastinal mass or any primary or metastatic pulmonary disease), type of central venous line (CVL) and CVL‐dysfunction (difficulty of blood draw, infusion or documented CVL infection) on the risk of developing TE.

Results

Fifty‐seven of 726 patients [7.9%; 95% confidence intervals (CI); 6.0,10.0] developed TE; children with brain tumors (n = 201) had significantly lower prevalence of TE (0.5%; P < 0.001). Older patients had increased risk of developing TE compared to younger patients [Odds ratios (OR) 1.8; 95% CI; 1.0,3.2; P = 0.036]. Children with acute lymphoblastic leukemia (ALL) (OR 4.6; 95% CI; 1.8, 12.3; P = 0.002), lymphoma (OR 3.8; 95% CI; 1.3, 11.1; P = 0.016), and sarcoma (OR 4.3; 95% CI; 1.4, 13.3; P = 0.012) had an increased risk of TE. Subgroup analyses showed that patients with CVL‐dysfunction and intra‐thoracic disease had a higher prevalence of TE compared to those without CVL‐dysfunction (22.8% vs. 8.8%; 95% CI; 4.0, 24.3; P = 0.006) and intra‐thoracic disease (18.0% vs. 6.1%; 95% CI; 2.4, 21.4; P = 0.02).

Conclusions

TE is common in children with cancer. Age and type of cancer are independent risk factors for TE in children with non‐CNS cancers. CVL‐dysfunction and intra‐thoracic disease are significantly associated with the diagnosis of TE. Pediatr Blood Cancer 2008;51:792–797. © 2008 Wiley‐Liss, Inc.
Differential diagnosis of lipoma‐like lipoblastoma
Authors: Morerio Cristina , Nozza Paolo , Tassano Elisa , Rosanda Cristina , Granata Claudio , Conte Massimo , Panarello Claudio
Published: September 2008

Lipoblastomas are rare benign tumors of white fatty tissue that occur primarily in young children. Occasionally, heterogeneity of morphological appearance and histological overlap with other lipogenic tumors are described. In such cases fluorescence in situ hybridization (FISH) analysis of PLAG1, a gene specifically rearranged in lipoblastoma, is necessary to prevent misdiagnosis. We present a case of lipoblastoma arising in an atypical site with histological features characteristic of lipoma. The correct diagnosis was made possible on cytogenetic grounds through the identification of the characteristic PLAG1‐HAS2 fusion gene, thus allowing an appropriate clinical approach. Pediatr Blood Cancer 2009;52:132–134. © 2008 Wiley‐Liss, Inc.
Noninvasive ventilation in large postoperative flail chest
Authors: Piastra Marco , De Luca Daniele , Zorzi Giulia , Ruggiero Antonio , Antonelli Massimo , Conti Giorgio , Pietrini Domenico
Published: September 2008

An 11‐year‐old male developed a severe respiratory failure due to a iatrogenic flail chest following a surgery for removing a large chest wall area. A rare Ewing sarcoma was histologically diagnosed and intensive chemotherapy was administered. Postoperatively, because of the failure in ventilation weaning, the patient was electively extubated and noninvasive positive pressure ventilation through face‐mask was provided. Respiratory support avoided asynchronous paradoxical movements and achieved pneumatic stabilization. Clinical and respiratory improvement allowed a successful weaning from ventilator. Pediatr Blood Cancer 2008;51:831–833. © 2008 Wiley‐Liss, Inc.
Kinetics and mechanism for acid‐catalyzed disproportionation of 2,2,6,6‐tetramethylpiperidine‐1‐oxyl
Authors: Sen Vasily D. , Golubev Valery A.
Published: September 2008

Disproportionation of cyclic nitroxyl radicals (NRs) in acid solutions is of key importance for the chemistry of these compounds. Meanwhile, the data reported on the mechanism of this reaction in dilute acids are inconsistent with those on the stability of NRs in concentrated acids. Here we have examined the kinetics and stoichiometry for the disproportionation of 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (1) in aqueous H2SO4 (1.0–99.3 wt%) and found that (1) the disproportionation of 1 proceeds by the same mechanism over the entire range of acid concentrations, (2) the effective rate constant of the process exhibits a bell‐shaped dependence on the excess acidity function X peaked at X = −pK1H+ = 5.8 ± 0.3, (3) a key step of the process involves the oxidation of 1 with its protonated counterpart 1H+ yielding oxopiperidinium cation 2 and hydroxypiperidine 3 at a rate constant of (1.4 ± 0.8) × 105 M−1 · s−1, and (4) the reaction is reversible and, upon neutralization of acid, disproportionation products 2 and 3H+ comproportionate to starting 1. In highly acidic media, the protonated form 1H+ is relatively stable due to a low disproportionation rate. Based on the known and newly obtained values of equilibrium constants, both the standard redox potential for the 1H+
/3 pair (955 ± 15 mV) and the pH‐dependences have been calculated for the reduction potentials of 1 and 2 to hydroxylamine 3 that is in equilibrium with its protonated 3H+ and deprotonated 3− forms. The data obtained provide a deeper insight into the mechanism of nitroxyl‐involving reactions in chemical and biological systems. Copyright © 2008 John Wiley & Sons, Ltd.
Solvent effects on electronic absorption spectra of donor‐substituted 11,11,12,12‐tetracyano‐9, 10‐anthraquinodimethanes (TCAQs)
Authors: Bureš Filip , Pytela Oldřich , Diederich François
Published: September 2008

Solvent effects on the electronic absorption spectra of donor‐substituted 11,11,12,12‐tetracyano‐9, 10‐anthraquinodimethanes (TCAQs) 1–3 have been investigated in 32 well‐selected solvents. These compounds were chosen as model structures for charge‐transfer chromophores featuring second‐ and third‐order nonlinear optical properties. The resulting data were evaluated by means of theoretical models and (semi)empirical correlations determining the optical properties related to electron distribution and polarizability. We found that solvent effects on a polar D‐π‐A system do not depend on the donor/acceptor orientation (HOMO/LUMO localization) but especially on the length of the π‐system in between. The observed solvent effects are described with high accuracy by the applied theoretical models and linear combinations of physical quantities. Solvent polarization, permanent dipole moment, and molar volume substantially affect the longest‐wavelength absorption maxima. Solvent‐induced bathochromic shift resulting from the solvent polarity is described with high accuracy by the Born function. On the other hand, hypsochromic effects of the solvent permanent dipole moment are caused due to the slower reorganization of molecular dipoles compared with the rate of excitation. Solvent polarizability shifts the longest‐wavelength absorption maxima bathochromically with increasing length of the π‐conjugated system. Whereas this effect could be suitably described by the Onsager‐induced polarizability, the orientation polarizability was not found to be important. The solvent molar volume as a hypsochromic shift‐inducing factor is only relevant if the size of the solute and solvent molecules are comparable. If the size of the solute is considerably larger than that of the solvent molecules, the solvent behaves as a ‘shape continuum.’ Copyright © 2008 John Wiley & Sons, Ltd.
Geography matters: patterns of spatial homogamy in the Netherlands
Authors: Haandrikman Karen , Harmsen Carel , van Wissen Leo J. G. , Hutter Inge
Published: September 2008

‘Cupid may have wings, but apparently they are not adapted for long flights.’ Studies on the spatial dimension of the partner market have found that the number of marriages declines as the distance between potential spouses increases. This paper explores the role of geographical distance in partner choice in the Netherlands. The availability of unique integral micro data from the population register enables us to study spatial homogamy among all new cohabiters. Spatial homogamy is measured by calculating distances between partners before cohabitation. The explorative study shows that geography matters: Dutch persons choose spatially homogamous partners. Spatial homogamy is influenced by demographic factors. With increasing age, spatial homogamy increases. Moreover, those who live with their parents and those who are single parents before cohabitation live significantly shorter to their future partners. Spatial homogamy also exhibits a distinct spatial pattern. However, conditional on population size and geographical location, long distances between partners in peripheral areas become insignificant. Finally, the distance between partners decreases as urbanisation increases. The findings stimulate the discussion on the role of cultural factors in partner choice. Copyright © 2008 John Wiley & Sons, Ltd.
‘Estimating with Confidence’ and hindsight: new UK small‐area population estimates for 1991
Authors: Norman Paul , Simpson Ludi , Sabater Albert
Published: September 2008

Population estimates are used in a variety of applications including the monitoring of social trends, the distribution of financial resources and assessment of demand for housing, schooling, employment and other goods and services. In many countries the primary source informing population estimates is a national census. A census, however, is not a perfect source. Even after imputation of missing households, the UK's 1991 Census counts were lower than expected. In the 1990s, the Estimating with Confidence project (EwC) distributed official non‐response data for local authority districts on a small area‐specific basis to allow for underenumeration, timing changes between census day and the mid‐year, armed forces adjustments and the transfer of students from home to term‐time addresses. The EwC‐enhanced census counts became accepted as the ‘gold standard’ for mid‐1991 small area populations and were widely used in research.

Following the 2001 Census, evidence suggested that previous official upward adjustments to 1991 populations were too large. Revisions were retrospectively made to 1991 non‐responses and to the official annual time‐series of subnational mid‐year population estimates. For the UK's small areas, here we have revised the original EwC non‐response allowances, converted the output to more contemporary geographies, and extended the estimates detail to single year of age. As a result, the 1991 EwC small‐area estimates are now consistent and comparable with the 2001 Census population definition and geography and the 1981–2001 official population time‐series. Our revised UK‐coverage small‐area population estimates can underpin late twentieth century local‐area social analyses. Given the very detailed geographical and demographic detail in the estimates, we recommend these resources are used as building bricks for aggregation to larger areas and to application‐relevant age bands. We present example calculations to assess differences which occur when a revised population estimate is used for the calculation of population change and as the denominator in demographic rates. Re‐worked research affects demographic, health and social indicators, especially the ranking of areas' population and population change, although the extent of the revisions often may not result in different conclusions being drawn about trends and patterns. Copyright © 2008 John Wiley & Sons, Ltd.
Use of different Zn precursors for the deposition of Zn(S,O) buffer layers by chemical bath for chalcopyrite based Cd‐free thin‐film solar cells
Authors: Sáez‐Araoz R. , Ennaoui A. , Kropp T. , Veryaeva E. , Niesen T. P. , Lux‐Steiner M. Ch.
Published: September 2008

Progress in fabricating Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells with Zn(S,O) buffer layers prepared by chemical bath deposition (CBD) is discussed. The effect of different Zn salt precursors on solar cell device performance is investigated using production scale CIGSSe absorbers provided by AVANCIS GmbH & Co. KG. The CBD process has been developed at the Hahn‐Meitner‐Institut (HMI) using zinc nitrate, zinc sulphate or zinc chloride as zinc precursor. An average efficiency of 14.2 ± 0.8% is obtained by using one‐layer CBD Zn(S,O) The dominant recombination path for well performing solar cells is discussed based on the results obtained from temperature dependent J (V) analysis. The structure and morphology of buffer layers deposited using zinc nitrate and zinc sulphate has been studied by means of transmission electron micrographs of glass/Mo/CIGSSe/Zn(S,O) structures. Results show a conformal coverage of the absorber by a Zn(S,O) layer of 15–25 nm consisting of nanocrystals with radii of ∼5 nm. XAES analysis of the buffer layer reveals a similar surface composition for buffer layers deposited with zinc nitrate and zinc sulphate. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural properties of ultrathin InGaN/GaN quantum wells
Authors: Sahonta S.‐L. , Komninou Ph. , Dimitrakopulos G. P. , Salcianu C. , Thrush E. J. , Karakostas Th.
Published: September 2008

A high indium‐content blue light‐emitting diode (LED) structure grown on silicon (111), consisting of five very thin MOCVD‐grown In0.2Ga0.8N quantum wells (QWs), is shown by high resolution transmission electron microscopy (HRTEM) to contain structural defects in the active region. HRTEM imaging reveals QWs containing stacking faults and also gaps ranging between 5 nm and 50 nm in length which isolate separate regions of QW of similar dimensions to the gaps. The relatively high internal quantum efficiency of the structure is attributed to enhanced confinement of carriers via the ultrathin QWs, the strained sections of QW between the gaps, and by the sections of QW with sphalerite crystal structure, identified by characteristic stacking fault phase contrast in HRTEM images. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Direct laser printing of biotin microarrays on low temperature oxide on Si substrates
Authors: Boutopoulos C. , Andreakou P. , Kafetzopoulos D. , Chatzandroulis S. , Zergioti I.
Published: September 2008

Laser Induced Forward Transfer (LIFT) technique is a direct‐write method allowing the effective deposition of a wide range of materials with high spatial resolution. In this work, we present the direct printing of microarrays from a biotin solution by using a Nd:YAG laser (266 nm wavelength, 4ns pulse duration). Standard materials of microelectronics such as Si and Low Temperature Oxide on Si (LTO/Si) were used as receiving substrates. For the LTO substrate, a detailed study for the optimum surface functionalization was carried out as it is a common passivation layer for biosensors. The laser beam parameters, such as the energy density and the beam size, were systematically varied in order to evaluate the effect on the transferred droplets. Furthermore, the energy density threshold for the ejection of the droplets was defined. Finally, the viability of the deposited droplets was demonstrated through the biotin–streptavidin reaction on silane coated LTO/Si substrates. This reaction was confirmed by fluorescence microscopy. These results have shown that the LIFT process can be used for biosensors and possibly for label‐free detection by the combination of the method with capacitive sensors, sensors based on cantilevers or other sensors with electrical output. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selective photochemical etching of GaN films and laser lift‐off for microcavity fabrication
Authors: Trichas E. , Xenogianni C. , Kayambaki M. , Tsotsis P. , Iliopoulos E. , Pelekanos N. T. , Savvidis P. G.
Published: September 2008

Wavelength dependent photochemical etching of GaN films reveals strong dependence of the photocurrent on the excitation wavelength. Sharp increase in the photocurrent with increasing photon energy is attributed to the onset of absorption above the GaN bandgap. The etching rate of GaN films strongly correlates with the measured photocurrent. No photocurrent and etching is observed for AlGaN films under same conditions. The method could pave the way to the development of truly selective self‐stop etching of GaN on AlGaN yielding smooth surfaces for the fabrication of GaN based microcavities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Internal friction investigation of reverse martensitic transformation in oil‐quenched Ni64Al36 alloy
Authors: Zhou Z. C. , Yan Y. J. , Zhong M.
Published: September 2008

Low‐frequency internal friction investigation of reverse martensitic transformation in oil‐quenched Ni64Al36 alloy has been carried out using a multifunctional internal friction apparatus from room temperature to 400 °C and additionally differential scanning calorimetry and X‐ray diffraction experiments were also completed. It has been shown that an internal friction peak presents at about 220 °C in the internal friction–temperature curve during heating for the oil‐quenched Ni64Al36 alloy but not for the furnace‐cooled Ni64Al36 alloy. The peak still appears during cooling and the peak temperature shifts to lower temperature. The changes of the peak temperature positions cannot be visibly observed when the vibration frequency is changed. The peak heights increase with decreasing vibration frequency and increasing heating rate, being linearly directly proportional to $ \dot T / f $ It has been suggested that the internal friction peak results from reverse martensitic transformation of L10 → γ during heating and originates from martensitic transformation of γ → L10 during the subsequent cooling process. The influence of the thermal cycles on the transformation is not observed for the limited thermal cycles. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Superlensing with plane plates consisting of dielectric cylinders in glass envelopes
Authors: Foca E. , Sergentu V. V. , Daschner F. , Tiginynau I. M. , Ursaki V. V. , Knöchel R. , Föll H.
Published: September 2008

The approach of designing negative‐refractive‐index materials on the basis of dielectric rods with a gradient of the dielectric constant is tested experimentally. A triangular‐lattice plane‐parallel slab assembled from multilayer dielectric rods with a refractive index approximating a fish‐eye profile is shown to exhibit excellent focusing properties for the TM polarized electromagnetic radiation at frequencies defined by the structural parameters of the slab. A clearly defined super‐resolution effect is observed at corresponding frequencies, the width of the focal spot down to a quarter of the wavelength being achieved. The experimental data are partially verified by simulations which show a very good match to the measurements. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)