bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient enzymatic regioselective benzoylation of 5‐fluorouridine catalysed by Novozym 435
Authors: Wu Jian , Zong Min‐Hua , Wu Hong , Lou Wen‐Yong
Published: February 2008

BACKGROUND: This work focuses on developing a mild, efficient and regioselective enzymatic procedure to synthesise 5′‐O‐benzoyl‐5‐fluorouridine, a more powerful antitumour drug than 5‐fluorouridine itself, and examining the influences of several key variables on the reaction.

RESULTS: The enzymatic regioselective benzoylation of 5‐fluorouridine can be successfully conducted with Novozym 435. The end‐product was confirmed to be 5′‐O‐benzoyl‐5‐fluorouridine by 13C nuclear magnetic resonance analysis. A co‐solvent mixture of hexane and tetrahydrofuran (THF) (50:50 v/v) was found to be the best reaction medium. The optimal initial water activity, molar ratio of vinyl benzoate to 5‐fluorouridine and reaction temperature were 0.07, 25:1 and 70 °C respectively. Under the optimised conditions the initial reaction rate, substrate conversion and regioselectivity were found to be 32.8 mmol L−1 h−1, 98.9% and > 99% respectively. In addition, Novozym 435 still maintained 88.2% of its original activity even after being reused for ten batches at 70 °C, indicating excellent thermal and operational stability of the enzyme in the co‐solvent mixture of hexane and THF.

CONCLUSION: The results clearly show that the Novozym 435‐catalysed regioselective benzoylation of 5‐fluorouridine is a novel and facile route for efficient preparation of 5′‐O‐benzoyl‐5‐fluorouridine with potential antitumour activity. Copyright © 2008 Society of Chemical Industry
Influence of light quality and intensity in the cultivation of Spirulina platensis from Toliara (Madagascar) in a closed system
Authors: Ravelonandro Pierre H , Ratianarivo Dominique H , Joannis‐Cassan Claire , Isambert Arsène , Raherimandimby Marson
Published: February 2008

BACKROUND: Spirulina platensis (Toliara, Madagascar) provides a food supplement which can fight against malnutrition and food insufficiency in Madagascar. In this country, the current production from three open basins is not sufficient to cover needs, and presents drawbacks such as low productivity and possible contamination. Thus cultivation of S. platensis in a closed photobioreactor opens the possibility of extending this microalga production. In this study, the influence of colour and intensity of the light on S. platensis growth and protein content was investigated in a bubble column.

RESULTS: Growth kinetics were obtained for four colours (green, white, red and blue) and four intensities (400, 800, 1000 and 1200 lux) of light. The influence of light colour on Spirulina growth was discussed. The highest productivity (183.6 mg L−1 d−1) and concentration (2643 mg L−1) were obtained for green light at 1200 lux. The protein content was 58%.

CONCLUSION: Using green light allows improvement of S. platensis growth. Performance obtained with the closed system was higher than that reported in the literature. Copyright © 2008 Society of Chemical Industry
Lipase‐catalyzed ethanolysis of soybean oil in a solvent‐free system using central composite design and response surface methodology
Authors: Rodrigues Rafael Costa , Volpato Giandra , Ayub Marco Antônio Záchia , Wada Keiko
Published: February 2008

BACKGROUND: In this work we describe the synthesis of ethyl esters, commonly known as biodiesel, using refined soybean oil and ethanol in a solvent‐free system catalyzed by lipase from Thermomyces lanuginosus. Central composite design and response surface methodology (RSM) were employed to optimize the biodiesel synthesis parameters, which were: reaction time, temperature, substrate molar ratio, enzyme content, and added water, measured as percentage of yield conversion.

RESULTS: The optimal conditions obtained were: temperature, 31.5 °C; reaction time, 7 h; substrate molar ratio, 7.5:1 ethanol:soybean oil; enzyme content, 15% (g enzyme g−1 oil); added water, 4% (g water g−1 oil). The experimental yield conversion obtained under these conditions was 96%, which is very close to the maximum predicted value of 94.4%. The reaction time‐course at the optimal values indicated that 5 h was necessary to obtain high yield conversions.

CONCLUSION: A high yield conversion was obtained under the optimized conditions, with relative low enzyme content and short time. Comparison of predicted and experimental values showed good correspondence, implying that the empirical model derived from RSM can be used to adequately describe the relationship between the reaction parameters and the response (yield conversion) in lipase‐catalyzed biodiesel synthesis. Copyright © 2008 Society of Chemical Industry
Insulated hsp70B′ promoter: stringent heat‐inducible activity in replication‐deficient, but not replication‐competent adenoviruses
Authors: Rohmer Stanimira , Mainka Astrid , Knippertz Ilka , Hesse Andrea , Nettelbeck Dirk M.
Published: February 2008

Background

Key to the realization of gene therapy is the development of efficient and targeted gene transfer vectors. Therapeutic gene transfer by replication‐deficient or more recently by conditionally replication‐competent/oncolytic adenoviruses has shown much promise. For specific applications, however, it will be advantageous to provide vectors that allow for external control of gene expression. The efficient cellular heat shock system in combination with available technology for focused and controlled hyperthermia suggests heat‐regulated transcription control as a promising tool for this purpose.

Methods and results

We investigated the feasibility of a short fragment of the human hsp70B′ promoter, with and without upstream insulator elements, for the regulation of transgene expression by replication‐deficient or oncolytic adenoviruses. Two novel adenoviral vectors with an insulated hsp70B′ promoter were developed and showed stringent heat‐inducible gene expression with induction ratios up to 8000‐fold. In contrast, regulation of gene expression from the hsp70B′ promoter without insulation was suboptimal. In replication‐competent/oncolytic adenoviruses regulation of the hsp70B′ promoter was lost specifically during late replication in permissive cells and could not be restored by the insulators.

Conclusions

We developed novel adenovirus gene transfer vectors that feature improved and stringent regulation of transgene expression from the hsp70B′ promoter using promoter insulation. These vectors have potential for gene therapy applications that benefit from external modulation of therapeutic gene expression or for combination therapy with hyperthermia. Furthermore, our study reveals that vector replication can deregulate inserted cellular promoters, an observation which is of relevance for the development of replication‐competent/oncolytic gene transfer vectors. Copyright © 2008 John Wiley & Sons, Ltd.
Silica‐overcoated substrates for detection of proteins by surface‐enhanced Raman spectroscopy
Authors: Scholes F. H. , Bendavid A. , Glenn F. L. , Critchley M. , Davis T. J. , Sexton B. A.
Published: February 2008

Ag film over nanosphere (AgFON) substrates for surface‐enhanced Raman spectroscopy (SERS) are shown to be ineffective for the detection of proteins in phosphate buffer solution (PBS) because of the decomposition of the substrate resulting in a total loss of SERS activity. However, modification of these substrates with SiO2 overlayers overcomes this problem. The SiO2 overlayers are produced by filtered arc deposition (FAD) and are characterised by atomic force microscopy (AFM). Their porosity is examined using Raman spectroscopy and the detection of cytochrome c and bovine serum albumin in PBS is successfully demonstrated. These findings show promise for the detection of proteins in biologically relevant conditions using Ag‐based SERS substrates. Copyright © 2008 John Wiley & Sons, Ltd.
Application of micro‐ and nano‐HPLC to the determination and characterization of bioactive and biomarker peptides
Authors: Saz José María , Marina María Luisa
Published: February 2008

This article reviews the works published since 2001 (included) on the micro/nano‐HPLC analysis of bioactive and biomarker peptides. The main achievements related to the improvement of the detection sensitivity, quantitation repeatability and reproducibility, and separation selectivity are highlighted. A wide attention is paid to the application of micro/nano‐HPLC to the analysis of bioactive peptides in biological matrices. The uses of micro/nano‐HPLC in peptidomics to discover new endogenous bioactive peptides and to develop quantitation procedures to compare the levels of peptides of interest in two different biological samples are also considered. Finally, the application of micro/nano‐HPLC to the analysis of biomarker peptides for various diseases is also included in this review.
Photocatalytic decomposition of gaseous acetone using TiO2and Pt/TiO2catalysts
Authors: Ku Young , Tseng Kun‐Yu , Ma Chih‐Ming
Published: February 2008

Metallic platinum was photodeposited on TiO2particles, and morphological characteristics of the Pt/TiO2catalyst were determined. The dispersion of metallic platinum was uniform and did not alter the morphology of the TiO2particles. However, absorbance of the Pt/TiO2catalyst for light with wavelength more than 400 nm was significantly improved by the addition of metallic platinum. Gaseous acetone was decomposed in an annular photoreactor coated with TiO2or Pt/TiO2catalysts using a UV or a fluorescent lamp as light source. The decomposition of acetone with the application of a UV lamp was obviously enhanced for experiments conducted with Pt/TiO2catalyst. Decomposition of acetone was promoted considerably with increasing oxygen concentration for experiments conducted with oxygen less than 50,000 ppmv, yet the decomposition of acetone was kept relatively constant for experiments conducted with oxygen above 50,000 ppmv. On the basis of the mass balance for carbon species, the amount of organic intermediates formed for experiments conducted under various conditions was found to be minimal. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 209–216, 2008
A simulation of the mass‐transfer effects on the kinetics of solid–gas reactions
Authors: Ortega A.
Published: February 2008

A theoretical analysis of the influence of mass‐transfer effect on the kinetic of solid–gas reactions has been carried out by assuming that the partial pressures of the gases generated in the reaction are proportional to the reaction rate. The influence of mass‐transfer phenomena on the apparent activation energy, calculated by the isoconversional methods of Friedman, and on the reaction model is discussed. In the present study, simulated nonisotherm, isotherm, and controlled rate thermal analysis (CRTA) data have been used. Master plots based on the differential forms of the kinetic equations describing solid‐state reactions have been employed by using the concept of the generalized time (θ), introduced by Ozawa; this permits the application of these master plots to the kinetic analysis of reactions whatever the type of temperature program used for recording the experimental data. It has been shown that when the simulated mass‐transfer effect is present the variable effective activation energy E remains nearly constant while the reaction model approaches zero order. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 217–222, 2008
Fractional Allelic Imbalance Could Allow for the Development of An Equitable Transplant Selection Policy for Patients With Hepatocellular Carcinoma
Authors: Dvorchik Igor , Schwartz Myron , Fiel Isabel M. , Finkelstein Sydney D. , Marsh Wallis J.
Published: February 2008

Liver transplantation (LT) in the presence of hepatocellular carcinoma (HCC) remains a controversial issue because the current staging systems are not sufficiently predictive of outcomes. Paraffin blocks from 183 patients that underwent LT in the presence of HCC were collected. Molecular analysis was carried out blindly on the native liver specimens in all cases with respect to recurrence outcomes. The fractional allelic imbalance (FAI) rate index was determined in each case and was used to compare the acquired mutational load between different tumors. The FAI was determined from the microdissected tissue site displaying the greatest amount of acquired allelic loss. FAI was found to be the strongest predictor of recurrence followed by vascular invasion and then by tumor number or hepatic lobar involvement. Based on these findings, 3 prognostic models were constructed for selection of candidates for LT in patients with concomitant HCC. Molecular markers of tumor progression are the strongest predictors of HCC recurrence currently available, surpassing all components of the tumor-node-metastasis classification system for staging of malignant tumors (TNM), including vascular invasion. Incorporation of these molecular markers of tumor progression could help resolve the ongoing conundrum of organ allocation for patients with HCC.
Energy forms on conformal C1‐diffeomorphic images of the Sierpinski gasket
Authors: Freiberg Uta Renata , Lancia Maria Rosaria
Published: February 2008

The energy form on a conformal C1‐diffeomorphic image G of the Sierpinski gasket K is constructed by integrating the Lagrangian LG on G, which is given in terms of the pullback of the Lagrangian LK on K and of the differential of the diffeomorphism. The extension of this approach to the class of nested fractals is outlined. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Second‐order properties of the point process of nodes in a stationary Voronoi tessellation
Authors: Heinrich Lothar , Muche Lutz
Published: February 2008

In this paper we derive representation formulae for the second factorial moment measure of the point process of nodes and the second moment of the number of vertices of the typical cell associated with a stationary normal Voronoi tessellation in ℝd . In case the Voronoi tessellation is generated by a stationary Poisson process with intensity λ > 0 the corresponding pair correlation function gV,λ (r) can be expressed by a weighted sum of d +2 (numerically tractable) multiple parameter integrals. The asymptotic variance of the number of nodes in an increasing cubic domain as well as the second moment of the number of vertices of the typical Poisson Voronoi cell are calculated exactly by means of these parameter integrals. The existence of a (d − 1)st‐order pole of gV,λ (r) at r = 0 is proved and the exact value of limr →0 rd –1 gV,λ (r) is determined. In the particular cases d = 2 and d = 3 the graph of gV,1(r) including its local extreme points, the points of level 1 of gV, 1(r) and other characteristics are computed by numerical integration. Furthermore, an asymptotically exact confidence interval for the intensity of nodes is obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Best simultaneous approximation in L∞(μ, X)
Authors: Pakhrou Tijani
Published: February 2008

Let Y be a reflexive subspace of the Banach space X, let (Ω, Σ, μ) be a finite measure space, and let L∞(μ, X) be the Banach space of all essentially bounded μ ‐Bochner integrable functions on Ω with values in X, endowed with its usual norm. Let us suppose that Σ0 is a sub‐σ ‐algebra of Σ, and let μ0 be the restriction of μ to Σ0. Given a natural number n, let N be a monotonous norm in ℝn . We prove that L∞(μ, Y) is N ‐simultaneously proximinal in L∞(μ,X), and that if X is reflexive then L∞(μ0, X) is N ‐simultaneously proximinal in L∞(μ, X) in the sense of Fathi, Hussein, and Khalil [3]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Compact operators which factor through subspaces of lp
Authors: Prasad Sinha Deba , Kumar Karn Anil
Published: February 2008

Let 1 ≤ p ≤ ∞. A subset K of a Banach space X is said to be relatively p ‐compact if there is an 〈xn 〉 ∈ ls p (X) such that for every k ∈ K there is an 〈αn 〉 ∈ lp ′ such that k = σ∞n=1 αn xn . A linear operator T: X → Y is said to be p ‐compact if T (Ball (X)) is relatively p ‐compact in Y. The set of all p ‐compact operators Kp (X, Y) from X to Y is a Banach space with a suitable factorization norm κp and (Kp , κp ) is a Banach operator ideal. In this paper we investigate the dual operator ideal (Kd p , κd p ). It is shown that κd p (T) = πp (T) for all T ∈ B (X, Y) if either X or Y is finite‐dimensional. As a consequence it is proved that the adjoint ideal of Kd p is Ip ′, the ideal of p ′‐integral operators. Further, a composition/decomposition theorem Kd p = Πp K is proved which also yields that (Πmin p )inj = Kd p . Finally, we discuss the density of finite rank operators in Kd p and give some examples for different values of p in this respect. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A spectral integral representation for decomposable operators
Authors: Skripka Anna
Published: February 2008

For the operators commuting with a spectral measure, a Bartle type integral representation in the spirit of the one provided by the spectral theorem for normal operators is obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Double structures on rational space curves
Authors: Eivind Vatne Jon
Published: February 2008

There are very many non‐reduced schemes. In this paper, we consider two examples to back this statement: we give lists of double scheme structures on a twisted cubic, and we construct rank two bundles on projective 3‐space with prescribed Chern classes, from double structures on smooth rational curves. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Behavior of the constant in Korenblum's maximum principle
Authors: Wang Chunije
Published: February 2008

Let Ap (𝔻) (p ≥ 1) be the Bergman space over the open unit disk 𝔻 in the complex plane. Korenblum's maximum principle states that there is an absolute constant c ∈ (0, 1) (may depend on p), such that whenever |f (z)| ≤ |g (z)| (f, g ∈ Ap (𝔻)) in the annulus c < |z | < 1, then ∥f ≤ ∥g ∥. For p ≥ 1, let cp be the largest value of c for which Korenblum's maximum principle holds. In this note we prove that cp → 1 as p → ∞. Thus we give a positive answer of a question of Hinkkanen. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A constitutive model for unsaturated soil interfaces
Authors: Hamid Tariq B. , Miller Gerald A.
Published: February 2008

A constitutive model based on the disturbed state concept is presented to describe the behavior of interfaces in unsaturated soil. The model is an extension of an existing model developed for a sand–steel interface. As opposed to the original model, the modified model incorporates two independent stress variables, which are the net normal stress and matric suction. The saturated and dry state of the interface can be modeled as a special case using the constitutive model presented in this paper. The modified model is capable of capturing the main features of unsaturated interfaces observed during laboratory testing, including increasing shear strength and strain softening with increasing suction and net normal stress and increasing dilatancy with increasing suction. Laboratory tests were carried out on unsaturated interfaces in a modified direct shear test apparatus. The observed behavior of interfaces between unsaturated soil and steel plates (rough and smooth) is presented in comparison with model predictions. Copyright © 2008 John Wiley & Sons, Ltd.
Two‐point constitutive equations and integration algorithms for isotropic‐hardening rate‐independent elastoplastic materials in large deformation
Authors: Wang Zhi‐Qiao , Dui Guan‐Suo
Published: February 2008

This paper presents alternative forms of hyperelastic–plastic constitutive equations and their integration algorithms for isotropic‐hardening materials at large strain, which are established in two‐point tensor field, namely between the first Piola–Kirchhoff stress tensor and deformation gradient. The eigenvalue problems for symmetric and non‐symmetric tensors are applied to kinematics of multiplicative plasticity, which imply the transformation relationships of eigenvectors in current, intermediate and initial configurations. Based on the principle of plastic maximum dissipation, the two‐point hyperelastic stress–strain relationships and the evolution equations are achieved, in which it is considered that the plastic spin vanishes for isotropic plasticity. On the computational side, the exponential algorithm is used to integrate the plastic evolution equation. The return‐mapping procedure in principal axes, with respect to logarithmic elastic strain, possesses the same structure as infinitesimal deformation theory. Then, the theory of derivatives of non‐symmetric tensor functions is applied to derive the two‐point closed‐form consistent tangent modulus, which is useful for Newton's iterative solution of boundary value problem. Finally, the numerical simulation illustrates the application of the proposed formulations. Copyright © 2008 John Wiley & Sons, Ltd.
Increased uptake of non‐pathogenic E. coli via the follicle‐associated epithelium in longstanding ileal Crohn's disease
Authors: Keita ÅV , Salim SY , Jiang T , Yang P‐C , Franzén L , Söderkvist P , Magnusson K‐E , Söderholm JD
Published: February 2008

In Crohn's disease (CD), inflammation is driven by luminal commensal micro‐organisms; however, mechanisms of early phases of inflammation need further clarification. The earliest observable lesions of recurrent CD are microscopic erosions at the specialized follicle‐associated epithelium (FAE), which lines the Peyer's patches. Therefore, our aim was to investigate the mucosal barrier to non‐pathogenic bacteria in FAE of CD. The FAE of macroscopically normal ileum from patients with longstanding CD, ulcerative colitis, and controls was studied in Ussing chambers regarding electrophysiology and permeability to 51Cr‐EDTA, horseradish peroxidase, and non‐pathogenic E. coli strains. Transepithelial passage routes and uptake into dendritic cells were studied by confocal and electron microscopy. FAE of CD showed increased numbers of adherent bacteria, after E. coli exposure in Ussing chambers, as well as spontaneously in non‐exposed archival surgical tissues. Further, we found increased uptake of fluorescent E. coli K‐12 and HB101 across FAE of CD, but not in ulcerative colitis. Microscopy demonstrated intercellular and transcellular uptake of E. coli in CD, but only transcellular in controls. FAE exposed to E. coli demonstrated changes in conductance and 51Cr‐EDTA permeability, suggesting that bacteria affected the paracellular pathway in CD mucosa. Following bacterial uptake, CD mucosa also demonstrated an increased percentage of E. coli co‐localizing with dendritic cells, and augmented tissue release of TNF‐α. Our data present novel insights into the pathophysiology of CD by demonstrating a previously unrecognized defect of FAE barrier to bacteria in ileal CD, leading to increased load of commensal bacteria to the inductive sites of mucosal immunity. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Results in patients with cranial parameningeal sarcoma and metastases (Stage 4) treated on Intergroup Rhabdomyosarcoma Study Group (IRSG) Protocols II–IV, 1978–1997: Report from the Children's Oncology Group
Authors: Raney Beverly , Anderson James , Breneman John , Donaldson Sarah S. , Huh Winston , Maurer Harold , Michalski Jeff , Qualman Stephen , Ullrich Fred , Wharam Moody , Meyer William
Published: February 2008

Purpose

Determine outcome of patients with cranial parameningeal sarcoma and concurrent metastases treated on Intergroup Rhabdomyosarcoma Study Group (IRSG) Protocols II–IV.

Patients

We identified 91 patients in the database, which includes newly diagnosed subjects <21 years old with rhabdomyosarcoma (RMS) and undifferentiated sarcoma, and reviewed their charts in detail.

Results

The 54 males and 37 females were <1–19 years at diagnosis. Primary sites were nasopharynx‐nasal cavity, middle ear/mastoid and parapharyngeal area (“better” sites, 55%), paranasal sinus and infratemporal‐pterygopalatine area (“worse” sites, 42%), and other (3%). Sixty‐eight percent of informative patients had direct intracranial extension. Major metastatic sites at diagnosis were lung (63%), bone marrow (33%), and bone (27%). Treatment included vincristine, actinomycin D, and cyclophosphamide (VAC) chemotherapy and radiotherapy to the primary tumor and up to five metastatic sites/tissues.

Outcome

The estimated 10‐year failure‐free survival (FFS) rate was 32% (95% confidence interval [CI]: 22%, 42%). Sixty patients had progressive disease (N = 49) or death as a first event (N = 11); another developed myelodysplastic syndrome and died. Sites of first progression/relapse were distant (55%), local (12%), CNS extension (8%), mixed (6%), and uncertain (18%). Factors indicating likelihood of 10‐year FFS included tumor arising in “better”versus“worse” sites (FFS 46% vs. 18%,P = 0.02) and embryonalversusother histology (FFS 37% vs. 19%,P = 0.06).

Conclusions

Cure was possible for some patients with metastatic cranial parameningeal sarcoma. Patients with the best outlook had embryonal RMS located in the nasopharynx/nasal cavity, middle ear/mastoid, or parapharyngeal region. Distant metastases were the most frequent type of recurrence, indicating that more effective systemic agents are needed to eliminate residual disease. Pediatr Blood Cancer 2008;51:17–22. © 2008 Wiley‐Liss, Inc.
Risk determinants for catheter‐associated blood stream infections in children and young adults with cancer
Authors: Allen Rebekah C. , Holdsworth Mark T. , Johnson Cynthia A. , Chavez Cathy M. , Heideman Richard L. , Overturf Gary , Lemon David , Hunt W. Curtis , Winter Stuart S.
Published: February 2008

Background

Catheter‐associated blood stream infections (CABSI) are frequent complications encountered with cancer treatment. In order to understand which factors might predispose to CABSIs in children and young adults, we evaluated risk for infection in association with tumor type, catheter type, and setting of occurrence.

Methods

All pediatric oncology patients having a central venous catheter (CVC) with a tunneled external (TE) or totally implantable design (TID) were prospectively followed for the occurrence of a CABSI for 12 months. CABSIs were defined in accordance with the guidelines published by the Centers for Disease Control, and were quantified as the number of occurrences per 1,000 device days. Rates of CABSIs were stratified by tumor histology, type of catheter design, and setting of occurrence. Statistical comparisons were made using the Mantel‐Haenzel statistic and the Cox proportional hazard model.

Results

A total of 58 CABSIs were identified in 139 patients over a period of 35,935 CVC days. The overall CABSI rate was 1.6 infections per 1,000 CVC days (95% CI 1.2, 2.1). Stratified analysis demonstrated increased risk for CABSIs in hospitalized patients having TEs, and while patients with solid tumors were also at higher risk; this association was not supported by the Cox proportional hazard model.

Conclusion

While our baseline CABSI rate was comparatively lower than for other institutions, subset analyses identified that hospitalized cancer patients having TEs are at the highest risk for developing CABSIs. Our findings may help to guide improved methods of anticipating and controlling infections in immunocompromised patients. Pediatr Blood Cancer 2008;51:53–58. © 2008 Wiley‐Liss, Inc.
Fungal infection by Paracoccidioides brasiliensis mimicking bone tumor
Authors: Valera Elvis Terci , Mori Bianca Maria , Engel Edgard Eduard , Costa Igor Santos , Brandão Daniel Ferraciolli , Nogueira‐Barbosa Marcello Henrique , Queiroz Rosane Gomes de Paula , Silveira Vanessa da Silva , Scrideli Carlos Alberto , Tone Luiz Gonzaga
Published: February 2008

Paracoccidioides brasiliensis infection causes a systemic mycosis originally described in Latin America but with current reports of worldwide distribution. The clinical presentation of paracoccidiodomycosis as an isolated long‐bone lesion in children is quite unusual. This article describes a 10‐year‐old male with a lytic femoral bone lesion caused by P. brasiliensis infection that was first suspected of being of neoplasic etiology. The text also emphasizes the importance of including endemic fungal infections in the differential diagnosis of bone lesions. Pediatr Blood Cancer 2008;50:1284–1286. © 2008 Wiley‐Liss, Inc.
Incidence of Langerhans cell histiocytosis in children: A population‐based study
Authors: Stålemark Helen , Laurencikas Evaldas , Karis Jenny , Gavhed Désirée , Fadeel Bengt , Henter Jan‐Inge
Published: February 2008

Background

Langerhans cell histiocytosis is a rare disease of unknown etiology. We wanted to assess the population‐based incidence of LCH in a well‐defined cohort of children.

Methods

We identified all children <15‐years old treated with LCH during the 10 years period 1992–2001 at the Department of Pediatrics, Karolinska University Hospital in Stockholm, the referral center for children with LCH in Stockholm County. We also contacted the Departments of Dermatology, Orthopedics, and Neurosurgery for possible additional patients.

Results

Twenty‐nine children (16 males) with LCH were identified, with a median age at diagnosis of 3.8 years (2 months–13.7 years). All children but one had a definitive diagnosis of LCH. The minimum incidence of LCH is estimated to 8.9/106 children per year. At diagnosis, 20 children (69%) had single system (SS) and 9 (31%) multisystem (MS) manifestations. Five of the 20 children with SS eventually developed MS disease, thus 14 (48%) had MS involvement at the maximal extent of disease (4.3/106 children per year). Interestingly, 22 children (76%) were diagnosed during the fall (September–November, n = 12) and winter (December–February, n = 10) seasons, as compared to seven children during the spring (March–May = 1) and summer (June–August = 6) seasons (P = 0.005, Chi‐square).

Conclusions

The incidence of childhood LCH in our study is higher than previously reported. In our patient cohort, LCH was more commonly diagnosed during the fall and winter season as compared to the spring and summer season. Whether this seasonal variation can be confirmed in larger studies and whether it has relevance for LCH pathophysiology remains to be elucidated. Pediatr Blood Cancer 2008;51:76–81. © 2008 Wiley‐Liss, Inc.
Diabetic ketoacidosis during therapy for pediatric acute lymphoblastic leukemia
Authors: Roberson Jessica R. , Raju Sailaja , Shelso John , Pui Ching‐Hon , Howard Scott C.
Published: February 2008

Background

Hyperglycemia is common during therapy for acute lymphoblastic leukemia (ALL), but diabetic ketoacidosis (DKA) occurs rarely. Morbidity due to DKA in children with ALL has not been systematically studied.

Procedures

We reviewed risk factors and clinical consequences of DKA in patients undergoing therapy for ALL at SJCRH between 1991 and 2006.

Results

DKA occurred in 6 of 797 evaluable patients. Only older age at diagnosis of ALL was a risk factor for DKA. Four of six patients with DKA as compared to 232 of the other 791 patients were older than 10 years (P = 0.03). Race, sex, body mass index, leukemia immunophenotype, ALL risk category, white blood cell count at diagnosis, and treatment protocol were not associated with DKA. All patients were managed with intravenous fluids, dietary modification, and short‐term use of insulin. Patients were hospitalized for 4–12 days, with a median ICU stay of 1 day. In two patients, correction of hyperglycemia was too rapid, and two others experienced hypoglycemia due to insulin therapy. There were no permanent complications of DKA or its treatment. No patient required long‐term insulin use. No patient had recurrent DKA; only one of the six patients had a subsequent hyperglycemia episode. All six patients are alive in remission 6–13 years after diagnosis.

Conclusions

Patients with hyperglycemia during treatment for ALL should be screened for clinical evidence of DKA, which may require more intensive supportive care than those without ketoacidosis. The occurrence of DKA should not lead to alteration of ALL treatment. Pediatr Blood Cancer 2008;50:1207–1212. © 2008 Wiley‐Liss, Inc.
Solvent influence on the orthogonality of noncovalently functionalized terpolymers
Authors: Burd Caroline , Weck Marcus
Published: February 2008

Poly(norbornene) terpolymers containing palladated sulfur‐carbon‐sulfur (SCS) pincer complexes, cyanuric acid, and thymine moieties in their side‐chains were synthesized by ring‐opening metathesis polymerization. Functionalization of the terpolymers was achieved by self‐assembling (i) the Hamilton wedge to the cyanuric acid receptor, (ii) diaminopyridine to the thymine receptor, and (iii) pyridine to the palladated pincer complexes. While all three noncovalent interactions are fully orthogonal to each other in dichloromethane, the employment of a dioxane/chloroform solvent mixture results in the quantitative disassembly of one of the hydrogen bonding recognition units (the Hamilton wedge:cyanuric acid pair) during the metal‐coordination event. This disassembly is completely independent from the diaminopyridine: thymine hydrogen‐bonding pair and allows for the selective removal of one of the side‐chain functionalities. This removal occurs with a switch‐type mechanism: as one functionality is put on (the pyridine), another one (the Hamilton‐wedge receptor) is taken off quantitatively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1936–1944, 2008
Electrochemical and optical properties of novel donor‐acceptor thiophene‐perylene‐thiophene polymers
Authors: Koyuncu Sermet , Kus Mahmut , Demic Serafettin , Kaya İsmet , Ozdemir Eyup , Icli Siddik
Published: February 2008

In this study, donor‐acceptor type thiophene‐perylene‐thiophene monomers were synthesized and polymerized by both oxidative polymerization using FeCl3 as catalyst and the electrochemical process. UV–vis, FTIR, 1H NMR, and elemental analysis techniques were used for structural characterization. Thermal behaviors of these compounds were determined by using TGA system. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels and electrochemical and optical band gap values were calculated by using the results of cyclic voltammetry and UV–vis measurements, respectively. The number–average molecular weight (Mn), weight–average molecular weight (Mw), and polydispersity index (PDI) values of synthesized polymers were determined by size exclusion chromatography. Conductivity measurements of these polymers were carried out by electrometer by using a four‐point probe technique. The conductivity was observed to be increased by iodine doping. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1974–1989, 2008
Solid‐supported synthesis of well‐defined amphiphilic block copolymer from methacrylates
Authors: Nagai Daisuke , Fujii Asuka , Ochiai Bungo , Sudo Atsushi , Endo Takeshi
Published: February 2008

A new facile method for preparation of an amphiphilic block copolymer via a one‐pot sequential atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) and 2‐hydroxyethyl methacrylate (HEMA) on solid support was developed. As a model homopolymerization for the solid‐supported block copolymerization, ATRPs of MMA and HEMA in toluene and in 2‐butanone/1‐propanol solvent system were carried out, respectively. Crosslinked polystyrene beads bearing 2‐bromoisobutyrate moieties successfully initiated the polymerizations of MMA and HEMA in controlled manner. On the basis of the successful results, the one‐pot synthesis of amphiphilic block copolymer by changing the reaction medium was performed. After the ATRP of MMA in toluene at 90 °C for 1 h, the poly(MMA) formed on the beads were washed by continuous flow of 2‐butanone/1‐propanol under nitrogen with the aid of a glass filter in a U‐shaped glass vessel. Then, 2‐butanone/1‐propanol, copper chloride (I), 2,2′‐bipyridyl, and HEMA were added and heated at 50 °C for 48 h with shaking the vessel, followed by treatment with trifluoroacetic acid to isolate the well‐defined amphiphilic block copolymer, poly(MMA‐b‐HEMA). These demonstrated the feasibility of the present strategy for well‐defined synthesis of amphiphilic block copolymers via a one‐pot procedure. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1990–1997, 2008
Tripodal imidazole containing ligands for copper catalyzed ATRP
Authors: Yamamura Yuichi , Matyjaszewski Krzysztof
Published: February 2008

Tripodal imidazole containing ligands, bis((2‐pyridyl)methyl)(1‐methylimidazole‐2‐yl)methyl)amine (BPIA) and bis(1‐methylimidazole‐2‐yl)methyl)((2‐pyridyl)methyl)amine (BIPA), were synthesized and used for copper catalyzed atom transfer radical polymerization (ATRP) of n‐butyl acrylate (nBA). The molecular weights of poly(n‐butyl acrylate) (PnBA) catalyzed by CuBr/BPIA and CuBr/BIPA complexes increased linearly with nBA conversions and they were close to theoretical values with low polydispersities. ATRP equilibrium rate constant (KATRP) measurements showed that bothCuBr/BPIA and CuBr/BIPA complexes had high KATRP values, similar to that of CuBr/tri(2‐pyridylmethyl)amine (TPMA), which is one of the ATRP most active ligands. Activators regenerated by electron transfer (ARGET) ATRP of nBA with CuBr2/BPIA and CuBr2/BIPA complexes were also conducted and polymerization reached high nBA conversions, resulting in PnBA with low polydispersities. This suggests that the copper complexes with BPIA and BIPA were sufficiently stable and active to conduct ATRP when catalyst concentration was low. ARGET ATRP to form high molecular weight PnBA with CuBr2/BPIA and CuBr2/BIPA complexes was also successful. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2015–2024, 2008
Ethylene polymerizations, and the copolymerizations of ethylene with hexene or norbornene with highly active mono(β‐enaminoketonato) vanadium(III) catalysts
Authors: Tang Li‐Ming , Wu Ji‐Qian , Duan Yi‐Qun , Pan Li , Li Yan‐Guo , Li Yue‐Sheng
Published: February 2008

Five novel vanadium(III) complexes [PhN = C(R2)CHC(R1)O]VCl2(THF)2 (4a: R1 = Ph, R2 = CF3; 4b: R1 = t‐Bu, R2 = CF3; 4c: R1 = CF3, R2 = CH3; 4d: R1 = Ph, R2 = CH3; 4e: R1 = Ph, R2 = H) have been synthesized and characterized. On activation with Et2AlCl, all the complexes, in the presence of ethyl trichloroacetate (ETA) as a promoter, are highly active precatalysts for ethylene polymerization, and produce high molecular weight and linear polymers. Catalyst activities more than 16.8 kg PE/mmolV h bar and weight‐average molecular weights higher than 173 kg/mol were observed under mild conditions. The copolymerizations of ethylene and norbornene or 1‐hexene with the precatalysts were also explored, which leads to high molecular weight copolymers with high comonomer incorporation. Catalyst activity, comonomer incorporation, and polymer molecular weight as well as polydispersity index can be controlled over a wide range by the variation of precatalyst structure and the reaction parameters such as Al/V molar ratio, comonomer feed concentration, and polymerization temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2038–2048, 2008
Systematic investigation of functional core variation within hyperbranched polyglycerols
Authors: Barriau Emilie , Pastor‐Pérez Lourdes , Berger‐Nicoletti Elena , Kilbinger Andreas F. M. , Frey Holger , Stiriba Salah‐Eddine
Published: February 2008

A novel series of hyperbranched polyether polyols with various n‐alkyl amine cores (mono‐ and bifunctional) and photoactive cores (benzylamine and 1‐naphthylmethylamine) have been prepared. Polymerization of glycidol was carried out in two ways, starting directly from primary amine initiators and from bisglycidolized amine initiators. NMR spectroscopy and size exclusion chromatography (SEC) showed good control over the molecular weights only, when bisglycidolized amines were used. Molecular weights and polydispersity of the hyperbranched polyglycerols prepared with these initiator‐cores were in the range of 1600 to 8400 g/mol and of 1.5 to 2.5, respectively. MALDI‐ToF mass spectrometry confirmed covalent attachment of the functional cores to the hyperbranched polymers. When using the bis‐glycidolized amine‐initiators, only functionally initiated polymers could be observed. In contrast, the direct amine‐initiated polymers always showed the presence of nonfunctionalized PG homopolymer. Steady‐state and time‐resolved fluorescence measurements further support covalent attachment and site isolation of the functional initiators within the hyperbranched structure. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2049–2061, 2008
Synthesis, characterization, and nucleotidic chain cleavage ability of uncharged water soluble poly(ethylene glycol)‐fullerene derivatives with an amphiphilic character
Authors: Vitalini Daniele , Spina Emanuela , Dattilo Sandro , Mineo Placido , Scamporrino Emilio
Published: February 2008

Water‐soluble fullerenes containing two poly(ethylene glycol) branches [Full‐(PEG)2] were prepared starting from commercial poly(ethylene glycol)‐monomethyl ethers and C60 [Full‐(PEG)2]s chemical characterization was made by FT‐IR, NMR, and MALDI‐TOF mass spectrometric analyses. Their thermal stability was determined by TGA experiments. The capability of C60‐derivatives to induce oligonucleotide cleavage under visible light irradiation was also ascertained. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2154–2153, 2008
Synthesis of ABCD 4‐Miktoarm star‐shaped quarterpolymers by combination of the “click” chemistry with multiple polymerization mechanism
Authors: Wang Guowei , Luo Xiaolan , Liu Chao , Huang Junlian
Published: February 2008

Well‐defined ABCD 4‐Miktoarm star‐shaped quarterpolymers of [poly(styrene)‐poly(tert‐butyl acrylate)‐poly(ethylene oxide)‐poly(isoprene)] [star(PS‐PtBA‐PEO‐PI)] were successfully synthesized by the combination of the “click” chemistry and multiple polymerization mechanism. First, the poly(styryl)lithium (PS−Li+) and the poly(isoprene)lithium (PI−Li+) were capped by ethoxyethyl glycidyl ether (EEGE) to form the PS and PI with both an active ω‐hydroxyl group and an ω′‐ethoxyethyl‐protected hydroxyl group, respectively. After these two hydroxyl groups were selectively modified to propargyl and 2‐bromoisobutyryl group for PS, the resulted PS was used as macroinitiator for ATRP of tBA monomer and the diblock copolymer PS‐b‐PtBA with a propargyl group at the junction point was achieved. Then, using the functionalized PI as macroinitiator for ROP of EO monomer and bromoethane as blocking agent, the diblock copolymer PI‐b‐PEO with a protected hydroxyl group at the conjunction point was synthesized. After the hydrolysis, the recovered hydroxyl group of PI‐b‐PEO was modified to bromoacetyl and then azide group successively. Finally, the “click” chemistry between them was proceeded smoothly. The obtained star‐shaped quarterpolymers and intermediates were characterized by 1H NMR, FT‐IR, and SEC in detail. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2154–2166, 2008
The comonomer inducing selective β‐methyl elimination chain transfer: A new approach for end‐functionalizations of syndiotactic polypropylene‐based copolymers
Authors: Lin Wen‐Fu , Tsai Jing‐Cherng
Published: February 2008

The end‐functionalization of syndiotactic polypropylene‐based copolymers can be accomplished by conducting propylene polymerization in the presence of norbornene using Me2C(Cp)(Flu)ZrCl2/MAO as the catalyst. The detailed structural analyses clearly reveal the occurrence of the β‐methyl elimination chain transfer reaction that leads to the generation of the ethenyl group end‐capped syndiotactic polypropylene‐based propylene–norbornene copolymer. Subsequently, the ethenyl group end‐capped copolymer can be used for the preparation of other end‐functionalized syndiotactic polypropylene‐based copolymers by conducting organic functional group transformation reactions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2167–2176, 2008
Solvent‐free free‐radical frontal polymerization: A new approach to quickly synthesize poly(N‐vinylpyrrolidone)
Authors: Cai Xiaojing , Chen Su , Chen Li
Published: February 2008

The first synthesis of poly(N‐vinylpyrrolidone) without solvent by free‐radical frontal polymerization at ambient pressure is reported. The appropriate amounts of two reactants N‐vinyl‐2‐pyrrolidone (NVP) and initiator 2,2′‐azobis‐isobutyronitrile (AIBN) without solvent were mixed together at ambient temperature. Frontal polymerization was initiated by heating the wall of the tube with a soldering iron, and the resultant hot fronts were allowed to self‐propagate throughout the reaction vessel. Once initiated, no further energy was required for polymerization to occur. To suppress the fingers of molten monomer, a small amount of nanosilica was added. The dependence of the front velocity and front temperature on the AIBN concentration was thoroughly investigated. The as‐prepared polymers were characterized by gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). Results show that without postpolymerization solvent removal, waste production can be reduced. Solvent‐free FP could be exploited as a means for preparation of PVP with the potential advantage of higher throughput than solvent‐based methods. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2177–2185, 2008
Mechano‐reversible physical aging of elastic oriented syndiotactic polypropylene
Authors: Guadagno Liberata , Naddeo Carlo , Vittoria Vittoria
Published: February 2008

Syndiotactic polypropylene (sPP), obtained at 0 °C in the trans‐planar mesophase, was drawn at room temperature up to λ = 6, and left at room temperature for 1 year with fixed or relaxed ends. Data analysis allowed the clarification of the structure of the crystalline phases and their transformations during the aging. In both oriented samples similar structural changes were observed, although they were due to different aging mechanisms. The physical aging led to the crystallization in both samples of an oriented helical form, due to a partial transformation of the mesophase and of the amorphous phase. In the oriented sample aged with fixed ends, a small fraction of the crystalline trans‐planar form III became stable even by releasing the tension after 1 year. This last sample did not undergo the large shrinkage, always observed by unloaded sPP after drawing, and therefore was no more elastic. Also, the sample aged with free ends for 1 year showed a reduced elasticity in terms of both dissipated energy and permanent set. However, after a new deformation up to λ = 6, the fiber recovered its previous elasticity. Indeed a mechano‐reversibility was apparent for the oriented elastic sample of sPP aged at room temperature with free ends, leading to a renewed elasticity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 599–606, 2008
Relationship Between RDX Properties and Sensitivity
Authors: Doherty Ruth M. , Watt Duncan S.
Published: February 2008

An interlaboratory comparison of seven lots of commercially available RDX was conducted to determine what properties of the nitramine particles can be used to assess whether the RDX has relatively high or relatively low sensitivity. The materials chosen for the study were selected to give a range of HMX content, manufacturing process and reported shock sensitivity. The results of two different shock sensitivity tests conducted on a PBX made with the RDX lots in the study showed that there are measurable differences in the shock sensitivity of the PBXs, but the impact sensitivity for all of the lots is essentially the same. Impact sensitivity is not a good predictor of shock sensitivity for these types of RDX. Although most RDX that exhibits RS has low HMX content, that characteristic alone is not sufficient to guarantee low sensitivity. A range of additional analytical chemistry tests were conducted on the material; two of these (HPLC and DSC) are discussed within.