bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Weight and Branching Distribution of a High Performance Metallocene Ethylene 1‐Hexene Copolymer Film‐Grade Resin
Authors: Vadlamudi M. , Subramanian G. , Shanbhag S. , Alamo R. G. , Varma‐Nair M. , Fiscus D. M. , Brown G. M. , Lu C. , Ruff C. J.
Published: September 2009

Summary: The bivariate, or cross branching distribution of a gas‐phase produced, film‐grade ethylene 1‐hexene copolymer with enhanced Elmendorf tear in machine direction, MD, and in transverse direction, TD, (> 400 g/mil) and high dart impact has been characterized through the analysis of fractions obtained by molecular weight and 1‐hexene composition. The molecular weight fractions, obtained by a solvent‐non‐solvent fractionation technique, are each mixtures of molecules with at least two different 1‐hexene compositions, one component with a constant relatively high density (∼1 mol% hexene) and a second of a lower density broadly distributed along the molecular weight fractions. The content of the low density component increases with increasing molecular weight of the fraction while the level of 1‐hexene decreases. The mixed compositional character of these fractions is easily inferred by their high crystallization rates and both high melting and crystallization temperatures compared to the values of model random ethylene copolymers. The set of compositional fractions obtained by TREF display an increasing 1‐hexene concentration with increasing molecular weight, and except for the highest molecular weight components (Mw > 150,000 g/mol) their melting and crystallization behavior followed the random pattern. Higher than expected melting temperatures and a constancy of the high melting temperature peak with increasing crystallization temperature, suggests that the intra‐chain 1‐hexene distribution of the highly branched, high molecular weight fraction deviates strongly from the random behavior. These structural features and the bimodal character of the composition distribution of this resin, that contains high molecular weight chains with both low and high 1‐hexene contents, are correlated with the enhanced key film properties.
Advances in Crystallization Elution Fractionation
Authors: Monrabal B. , Romero L. , Mayo N. , Sancho‐Tello J.
Published: September 2009

Summary: Crystallization Elution Fractionation has been optimized to improve resolution power and reduce co‐crystallization. Most important step to be optimized is the first separation cycle of Dynamic Crystallization which can be investigated with the help of Crystallization Analysis Fractionation experiments. A new approach to reduce co‐crystallization and improve resolution is presented by applying successive cooling and heating cycles in a long column. The new process known as Multiple Crystallization Elution Fractionation adds extended separation at each cooling and heating cycles.
Solution Crystallization Analysis by Laser Light Scattering (SCALLS)
Authors: van Reenen Albert , Brand Margaretha , Rohwer Erich , Walters Piet
Published: September 2009

Summary: Solution crystallization analysis by laser light scattering offers a direct way of studying the solution crystallization of polyolefins. The technique yields similar results to Crystaf, but in a shorter time and with apparently greater sensitivity in some cases. The use of SCALLS is demonstrated for the study of selected propylene/higher α‐olefin copolymers. Some conclusions are also drawn regarding the effect of molecular weight on the solution crystallization of polyolefins.
Fractionation and Crystallization of Isotactic Poly(propylenes) Prepared with a Heterogeneous Transition Metal Catalysts
Authors: Amer Ismael , van Reenen Albert
Published: September 2009

Summary: A series of poly(propylenes) (PPs) were prepared by slurry polymerization using a MgCl2‐supported transition metal catalyst. Two different external donors (EDs) were used: diphenyl dimethoxysilane (DPDMS) and methylphenyl dimethoxysilane (MPDMS). The molecular weight (MW) of the PPs was controlled using molecular hydrogen that was used as a transfer agent. To obtain materials with differing molecular weight and similar tacticities, polymers were fractionated with prep‐TREF. DSC analyses of blends of TREF fractions showed that the crystallization behaviour of the polymer blends are strongly affected by the configuration (tacticity) and MW of the PP.
Comparison of Fractionation Methods for the Characterisation of Short Chain Branching as a Function of Molecular Weight in Ethylene 1‐Olefin Copolymers
Authors: Piel Christian , Jannesson Eira , Qvist Åsa
Published: September 2009

Summary: Rapid and automated analysis of polyolefins is becoming essential for product development in industry. Quantifying short chain branching in ethylene 1‐olefin copolymers is common practice. Several different methods are available to perform this type of analysis. Preparative fractionation followed by subsequent analysis of the fraction by SEC and NMR, SEC‐FTIR and SEC‐IR were studied towards their applicability in polyolefin research and product development environment. The method of choice is defined by prerequisites such as accuracy, labour and time demands but also in versatility and practicability. The most accurate method is limited in terms of sample throughput and the most practical method is limited towards resolution of very low branching. SEC‐FTIR is capable to measure even heterogeneous low branched samples like bimodal high density polyethylene in rapid and satisfactory matter.
Application of a Multiple Linear Regression Model to Fixed Bands IR Detector Data in GPC‐IR Analysis of Polyolefins
Authors: Ortín A. , Monrabal B. , Montesinos J. , del Hierro P.
Published: September 2009

Summary: An infrared detector based on a set of narrow band optical filters was coupled to a high temperature Gel Permeation Chromatograph (GPC) producing continuous chromatograms of absorbance after the molar mass fractionation. A multiple linear regression (MLR) model was established to relate the measured absorbance to the average octene weight percent in industrial ethylene‐octene copolymer samples. This method is compared to univariate and multivariate band ratio models. The application of these models to produce molar mass compositional distributions is also outlined.
NMR Characterization of Ethylene/Propylene Copolymers and Propylene Impact Copolymers from MgCl2/TiCl4/ID+AlR3/ED Catalytic Systems
Authors: Camurati Isabella , Gioia Giuseppe , Piemontesi Fabrizio , Tartarini Stefano , Bonazza Alessandra , Farotti Annamaria , Colonnesi Marcello
Published: September 2009

Summary: The aim of this work was to study the comonomer distribution and the chemical composition distribution generated by different Ziegler‐Natta (ZN) systems (different internal donors, ID, dicyclopentadienyl‐dimethoxy silane, D donor, as the external donor) and to define the potentialities of different IDs to produce improved heterophasic copolymers (HECO). A methodology to quantify the amount of ethylene‐propylene copolymer (EP) portion in ZN‐HECO and ethylene content of the EP portion by 13C‐NMR was established. By using this method, it was possible to analyze the composition of ZN‐HECO obtaining results comparable to those obtained with a more complex fractionation technique.
Use of FT‐IR Spectrometry for On‐Line Detection in Temperature Rising Elution Fractionation
Authors: Zhang Zengrong
Published: September 2009

Summary: Temperature rising elution fractionation (TREF) has become a popular analytical technique that is able to determine the chemical composition distribution (CCD) of an ethylene/α‐olefin copolymer. An infrared (IR) detector is commonly used in TREF detection to measure the concentration of the polymer solution exiting the column as a function of elution temperature. The chemical composition of the eluting polymer at a given elution temperature can be predicted from the relationship between comonomer content and TREF elution temperature pre‐established through 13C nuclear magnetic resonance (NMR) analysis of TREF fractions. In this article, a Fourier transform infrared (FT‐IR) spectrometer has been coupled with a TREF instrument to provide a more powerful tool for characterizing complex olefin copolymers. The Partial Least Squares (PLS) technique is used when analyzing the FT‐IR spectra of the eluting polymer solutions. The power of on‐line FT‐IR detection in TREF is demonstrated using a few complex copolymer systems, such as ethylene‐octene copolymer, polystyrene grafted ethylene‐vinyl acetate copolymer and ethylene‐methyl acrylate copolymer.
Study of Multi‐Site Nature of Supported Ziegler‐Natta Catalysts in Ethylene‐Hexene‐1 Copolymerization
Authors: Matsko Mikhail A. , Echevskaya Ludmila G. , Zakharov Vladimir A. , Nikolaeva Marina I. , Mikenas Tatyana B. , Vanina Marina P.
Published: September 2009

Summary: Heterogeneity of active centers (AC) of titanium‐magnesium catalysts (TMC) and vanadium‐magnesium catalyst (VMC) in ethylene‐hexene‐1 copolymerization has been studied on the base of data of polymer molecular weight distribution (MWD) deconvolution technique and copolymer fractionation onto narrow fractions. It was found that 3 and 4 Flory components (groups of active centers) are required to describe experimental MWD curves of copolymers produced over TMC with different Ti content. In the case of VMC MWD of homopolymer and copolymer are characterized by set of 5 Flory components (5 groups of AC).

Different character of inter‐relationship between MW and short chain branching (SCB) was found for ethylene‐hexene‐1 copolymers produced over different catalysts: heterogeneous type in the case of TMC and more uniform for copolymer prepared over VMC. The content of Ti affects on the slope of that profile in copolymers produced over TMC.

The results indicated that TMC and VMC are different greatly on the heterogeneity of active centers to the formation of polymers with different molecular weights and to formation of copolymers with different inter‐relationship between MW and short chain branching. TMC produces polymers with more narrow MWD but it contains highly heterogeneous centers regarding comonomer reactivity ratios. VMC produces polymers with broad and bimodal MWD but it contains more homogeneous centers regarding comonomer reactivity ratios.
Simultaneous Deconvolution of Molecular Weight Distribution and Chemical Composition Distribution of Ethylene/1‐Olefin Copolymers Synthesized with Multiple‐Site‐Type Catalytic Systems
Authors: Anantawaraskul Siripon , Bongsontia Warawut , Soares João B.P.
Published: September 2009

Summary: Ethylene/1‐olefin copolymers synthesized with multiple‐site‐type catalytic systems typically exhibit broad molecular weight distribution (MWD) and chemical composition distribution (CCD). These microstrucral characteristics can be described by the presence of several active site types, each of which produces chains with distinct chain microstructures. In this work, a new approach to identify the number of active site types and chain microstructures produced on each active site type was developed based on simultaneous deconvolution of the bivariate MWD/CCD information. Chain microstructures produced on each active site type are assumed to follow Stockmayer's bivariate distribution. The proposed approach was validated with simulated data of model ethylene/1‐butene and ethylene/1‐octene copolymers.
Study of Very Low Temperature Crystallization Process in Ethylene/α‐Olefin Copolymers
Authors: Tarasova E. , Poltimäe T. , Krumme A. , Lehtinen A. , Viikna A.
Published: September 2009

Summary: The crystallization behavior of Ziegler‐Natta (ZN) and single site (SS) based ethylene/1‐butene and ethylene/1‐hexene copolymers and SS copolymer fractionated by composition and molar mass (MM) has been studied by differential scanning calorimetry. It was observed that in addition to the high temperature crystallization peak (HTCP), and for ZN copolymers in addition also to low temperature crystallization peak (LTCP), a very‐low temperature crystallization peak (VLTCP) is present at temperatures in between 60–75 °C. Peak temperature of VLTCP, TVLTCP, decreases with increasing comonomer content (Ccomon) at fixed MM. If Ccomon is kept approximately constant, TVLTCP increases with increasing MM. It turns out that TVLTCP does not depend on the type of catalyst used. The degree of crystallinity calculated from the VLTCP is independent of the chemical nature of the comonomers present, but slightly changes with Ccomon. It also steeply increases with MM and levels off at MM around 50 kg/mol. It was found that the crystallinity as related to the area of the VLTCP is catalyst type dependent, and is higher for the SS catalyst used compared to the ZN catalyst.
The Application of Silane as a Processing Aid (PA) in High Speed Extrusion
Authors: Amin Al‐Robaidi
Published: September 2009

Summary: Silane grafting is one of the most recently used technologies in manufacturing crosslinked products due to its enormous advantages. In highspeed extrusion Polymer Processing Aid materials (PPA) additives are usually a copolymer of vinylidene fluoride and hexafluoropropylene. They are added during extrusion process to improve the process‐ability and to eliminate surface meltfracture that's occurred during processing of various polyolefin's resins.

In this paper an attempt was made to investigate the application of VTEOS (Vinyltriethoxysilanes) and VTMOS (Vinyl trimethoxysilane) as a replacement of PPA and to determine its improvement in high speed extrusion of Polyethylene cable. It has been found that silane did contribute to eliminate meltfracture and improvement has been made. Nevertheless interaction phenomenon with carbon black and other additives did influencing significantly the performance of the silane and minimized its efficiency. Rheological measurements confirm this behaviour.

Factors such as chemical reaction, physical adsorption and abrasiveness are involved in many of these situations. The presence of other storage stabilizer in the polyethylene contributes in negative way as well for formulation deficiency. Special attention in selecting the ingredient to minimize adverse effect is also very important in assuring optimum effectiveness.
Metal Nanoparticle/Polymer Hybrid Particles: The Catalytic Activity of Metal Nanoparticles Formed on the Surface of Polymer Particles by UV‐Irradiation
Authors: Tamai Toshiyuki , Watanabe Mitsuru , Teramura Tomohiro , Nishioka Noboru , Matsukawa Kimihiro
Published: September 2009

Summary: Polymer particles decorated with metal nanoparticles were prepared by UV‐irradiation of polystyrene particles incorporating polymethylphenylsilane (PS/PMPS) and P[S‐co‐NIPAM]/PMPS particles (NIPAM: N‐isopropyl acrylamide) in the presence of metal salts. The metal nanoparticle/polymer hybrid particles were used as a catalyst for the reduction of 4‐nitrophenol with NaBH4. The Pd‐ and Ag‐P(S‐co‐NIPAM)/PMPS hybrid particles had larger metal nanoparticles and the lower catalytic activity than those of Pd‐ and Ag‐PS/PMPS, respectively. The surface functional group of the polymer particles affected the formation of the metal nanoparticles and their catalytic activity.
Simulation of Crystallization Analysis Fractionation (Crystaf) of Linear Olefin Block Copolymers
Authors: Anantawaraskul Siripon , Somnukguande Punnawit , Soares João B. P.
Published: September 2009

Summary: Linear olefin block copolymers (OBCs) have microstructures that are unique among polyolefins and exhibit properties that are different from those of other polyolefin elastomers. Characterizing their chain microstructures is a challenging task, as conventional characterization techniques cannot probe directly block length distribution or composition. In this work, we used a Monte Carlo model to predict the microstructure details of OBCs and a modified version of the Crystaf model previously developed in our groups to describe theoretical Crystaf profiles for model OBCs. This model can be used as a tool to interpret Crystaf results of these interesting new polyolefins and to relate them to OBC microstructures. Effects of polymerization parameters on OBC microstructure and Crystaf profiles were also discussed.
Urodynamic assessment of anterior vaginal wall surgery: A randomized comparison between colporraphy and transvaginal mesh
Authors: Ek Marion , Tegerstedt Gunilla , Falconer Christian , Kjaeldgaard Anders , Rezapour Masoumeh , Rudnicki Martin , Altman Daniel
Published: September 2009

Aims

To investigate the urodynamic effects of anterior vaginal wall prolapse surgery using either trocar guided transvaginal mesh or colporraphy.

Methods

A prospective, randomized multicenter trial enrolling 50 patients: 27 underwent anterior colporrhaphy and 23 anterior trocar guided transvaginal mesh. Urodynamic assessment was performed pre‐ and two months postoperatively.

Results

De novo stress urinary incontinence was significantly more common after trocar guided transvaginal mesh surgery compared to colporraphy. In comparison to baseline urodynamics, transvaginal mesh surgery resulted in a significant decrease in maximal urethral closing pressures (MUCP) whereas conventional anterior colporraphy had no significant effect on urodynamic parameters.

Conclusion

Trocar guided transvaginal mesh of anterior vaginal wall prolapse results in a lowering of MUCPs and increases the risk for de novo stress urinary incontinence compared to colporraphy. Neurourol. Urodynam. 29:527–531, 2010. © 2009 Wiley‐Liss, Inc.
Transurethral incision of the bladder neck to treat bladder neck dysfunction and voiding dysfunction in patients with high‐level spinal cord injuries
Authors: Ke Qian‐Sheng , Kuo Hann‐Chorng
Published: September 2009

Purpose

Detrusor–sphincter dyssynergia (DSD) and bladder neck dysfunction (BND) may cause voiding dysfunction in patients with spinal cord injury (SCI). We report the surgical outcomes in patients with high‐level SCI who underwent transurethral incision of the bladder neck (TUI‐BN).

Patients and Methods

Twenty‐two patients with SCI at or above the mid‐thoracic level who presented with voiding dysfunction due to BND with different types of DSD received TUI‐BN. Surgical outcome was determined by comparing preoperative with postoperative urodynamic parameters and clinical presentations. Satisfactory outcome was defined as having improvement of AUA/IPSS quality‐of‐life (QoL) index by ≥2.

Results

Among the patients, 19 (86.4%) were men and 3 (13.6%) were women. Thirteen patients had cervical and nine had thoracic SCI. Postoperatively, spontaneous voiding by abdominal triggering with an open urethral sphincter was noted in 19 patients (86%) and AD had resolved in 15 patients (88.2%). Detrusor pressure decreased significantly in 9 patients who had a high voiding pressure at baseline, and increased significantly in 13 patients who showed impaired detrusor contractility preoperatively. Eighteen patients (82%) reported satisfactory outcome, increased maximum flow rate (Qmax), decrease in postvoid residual (PVR) postoperatively. In addition, 82% of the patients were catheter free or reported a decrease in the frequency of clean intermittent catheterization after TUI‐BN.

Conclusions

TUI‐BN is effective in restoring spontaneous voiding, increasing Qmax, and decreasing PVR in high‐level SCI patients. TUI‐BN also leads to improvement in reducing bladder outlet resistance, reduction in occurrence of AD episodes, and improvement in QoL. Neurourol. Urodynam. 29:748–752, 2010. © 2010 Wiley‐Liss, Inc.
Comparison of ambulatory versus conventional urodynamics in females with urinary incontinence
Authors: Dokmeci Fulya , Seval Murat , Gok Haydar
Published: September 2009

Aims

We planned to compare the diagnostic accuracy of conventional urodynamics (UD) and ambulatory UD for the detection of detrusor over activity (DOA) and/or urodynamic stress incontinence (USI) in women presenting with urinary incontinence.

Methods

We prospectively enrolled 44 women with urinary incontinence and performed both urodynamic (UD) studies after they completed the UDI‐6 questionnaire. During ambulatory UD one micturition cycle was recorded. According to responses for individual items on the UDI‐6, patients were divided into three groups to define incontinence type irrespective of scoring.

Results

Mean age was 52.2 and mean duration of the symptoms was 4.94 years. The ambulatory UD detected an underlying pathophysiology of urinary incontinence (77.3%) in significantly more women than the conventional UD (6.8%) (P = 0.001). Among women with stress incontinence, 56% had USI on the ambulatory UD and none had abnormalities on the conventional UD (P = 0.002). Seventy‐two percent of women with mixed symptoms had abnormal findings (USI and/or DOA) on the ambulatory UD and 9% had abnormal findings on the conventional UD (P = 0.001).

Conclusions

Our findings suggest that ambulatory UD done in a clinical setting during one micturition cycle with unstandardized provocative activities detects an underlying pathophysiology (urge incontinence, stress incontinence, mixed incontinence) more often than conventional UD in supine position Conventional UD has a higher false‐negative rate in diagnosis of DOA and/or USI compared to ambulatory UD. Neurourol. Urodynam. 29:518–521, 2010. © 2009 Wiley‐Liss, Inc.
Distributed control of event floods in a large telecom network
Authors: Jagadish Chundury , Gonsalves Timothy A.
Published: September 2009

Events in a failing system can be generated so rapidly that they adversely impact the network as well as the network management system (NMS) manager. They may fail to get delivered and critical information may get lost. This problem becomes worse in a large and congested network. Today, in practice, a management station is often flooded with a huge number of redundant events, making it difficult for the operator to process them and take corrective actions. Methods are needed to limit the volume of event transmission and number of events presented to the operator, while ensuring delivery of important information to the NMS manager. These methods need to take care of the operators' changing needs in monitoring abstraction level, for various network elements (NE) based on time and NE severity state. In this paper we propose novel techniques for distributed control of events flood, by suppressing transient events at the source. These techniques do not add any delay in communicating a failure, while ensuring that only the important events are presented to the operator. Also, the correctness of event state at the NMS is not compromised. Moreover, these methods give flexibility to the operator to dynamically change the abstraction level needed from a network element, and limit the number of events presented to the operator. The implementation of these techniques is tested with real field event traces from various telecom networks. Results show that there is a substantial reduction in the event traffic in the network. Copyright © 2009 John Wiley & Sons, Ltd.
Weak formulation of Biot's equations in cylindrical coordinates with harmonic expansion in the circumferential direction
Authors: Östberg M. , Hörlin N. E. , Göransson P.
Published: September 2009

A weak symmetric form of Biot's equation in cylindrical coordinates with a spatial Fourier expansion in the circumferential direction is presented. The solid phase displacement and the pore pressure are used as the dependent variables. The original three‐dimensional boundary value problem is here, due to the orthogonality of the harmonic functions and the rotationally symmetric geometry, decomposed into independent two‐dimensional problems, one for each harmonic function. This formulation provides a computationally efficient procedure for vibroacoustic finite element modelling of rotationally symmetric three‐dimensional multilayered structures including porous elastic materials. By numerical simulations, this method is compared with, and verified against, full three‐dimensional Cartesian coordinate system finite element models. Copyright © 2009 John Wiley & Sons, Ltd.
Modeling influences on acute care nurses' engagement in tobacco use reduction
Authors: Schultz Annette S.H. , Hossain Shahadut , Johnson Joy L.
Published: September 2009

Although nurses are encouraged to address patients' tobacco use, the integration of tobacco reduction into practice has not been consistent. An organizational behavior perspective was used to conceptualize hypothesized relationships among reported influencing factors (individual characteristics, role attitudes, perceived barriers, and workplace climate). Survey data collected at two Western Canadian hospitals (N = 214 nurses; 58% response) were used to test the model. The final model explained nearly 60% of variation in the nurses' tobacco reduction practice. Role attitude, perceived resource availability, co‐worker's activities, and ability were the strongest contributors. Nurses' smoking status indirectly influenced practice through shaping role attitudes and perceived ability. Diverse leverage points to enhance nurses' involvement in patients' tobacco use were identified. © 2009 Wiley Periodicals, Inc. Res Nurs Health 32:621–633, 2009
Star‐like polyfluorenes based on 2,4,6,8, 10,12‐hexabenzyl‐2,4,6,8,10,12‐hexaazaisowurtzitane caged‐core: toward non‐aggregating, blue‐light‐emitting polymers
Authors: Zhao Qian‐jin , Wu Wen‐hui
Published: September 2009

Multi‐functionality compound 2,4,6,8,10,12‐hexa(p‐bromo)‐benzyl‐2,4,6,8,10,12‐hexaazaiso‐wurtzitane (Br‐HBIW) was synthesized and used for the core of star‐like polymers. Star‐like polyfluorene based on 2,4,6,8,10,12‐hexabenzyl‐2,4,6,8,10,12‐hexaazaisowurtzitane (HBIW) caged‐core was synthesized by Suzuki coupling method. The comparative studies between the star‐like polyfluorene and the linear polyfluorene based on UV–Vis and photoluminescence (PL) spectra revealed that the bulky HBIW cage could reduce the chain aggregation and π–π interaction, so brought about improved PL quantum efficiency and annealing PL stability. Such results could be owed to the successful suppression of excimers formation, which originated from the incorporation of the HBIW cage and star‐like architecture. Copyright © 2009 John Wiley & Sons, Ltd.
2′‐chlorodeoxyadenosine (2‐CdA) as salvage therapy for Langerhans cell histiocytosis (LCH). results of the LCH‐S‐98 protocol of the histiocyte society
Authors: Weitzman Sheila , Braier Jorge , Donadieu Jean , Egeler R. Maarten , Grois Nicole , Ladisch Stephan , Pötschger Ulrike , Webb David , Whitlock James , Arceci Robert J.
Published: September 2009

Background

A prospective phase II Histiocyte Society study, LCH‐S‐98, evaluated the efficacy of 2‐chlorodeoxyadenosine (2‐CdA) monotherapy as salvage therapy in Langerhans cell histiocytosis (LCH).

Procedures

Patients with poor and intermediate risk LCH not responsive to initial therapy and patients with low‐risk chronic recurrent LCH were evaluated for response and survival after treatment with 2–6 courses of 2‐CdA.

Results

Forty‐six patients (55%) had involvement of risk organs; lung, liver, spleen, or hematopoetic system (RO+), 37 (45%) were RO−. Twenty‐two percent of RO+ patients had a good response while 44% progressed, 62% RO− patients responded, and 11% progressed. Two‐year predicted survival is 48% for RO+, 97% for RO− patients, 100% for RO+ patients reactivating in non‐risk organs, 67% for RO− patients reactivating in risk organs. Two‐year pSU for the entire group is 68%. Seventy‐three percent of patients with a poor response to 2‐CdA died. Sixty‐five percent patients >2 years old and 30% <2 years old survived. There was a median of 26 months from diagnosis to 2‐CdA for responders compared to a median of 5 months for non‐responders. Twenty‐one percent of patients treated <12 months and 57% treated >12 months from diagnosis responded.

Conclusion

2‐CdA is active in LCH. It produces a higher response rate in patients with low‐risk multisystem or multifocal bone disease than those with risk organ involvement. “Risk” patients who fail to respond to 2‐CdA have a high mortality. Patient age at 2‐CdA therapy and length of time from diagnosis to 2‐CdA significantly affect response and survival. Pediatr Blood Cancer 2009; 53:1271–1276. © 2009 Wiley‐Liss, Inc.
Systematic molecular genetic analysis of congenital sideroblastic anemia: Evidence for genetic heterogeneity and identification of novel mutations
Authors: Bergmann Anke K. , Campagna Dean R. , McLoughlin Erin M. , Agarwal Suneet , Fleming Mark D. , Bottomley Sylvia S. , Neufeld Ellis J.
Published: September 2009

Background

Sideroblastic anemias are heterogeneous congenital and acquired bone marrow disorders characterized by pathologic iron deposits in mitochondria of erythroid precursors. Among the congenital sideroblastic anemias (CSAs), the most common form is X‐linked sideroblastic anemia, due to mutations in 5‐aminolevulinate synthase (ALAS2). A novel autosomal recessive CSA, caused by mutations in the erythroid specific mitochondrial transporter SLC25A38, was recently defined. Other known etiologies include mutations in genes encoding the thiamine transporter SLC19A2, the RNA‐modifying enzyme pseudouridine synthase 1 (PUS1), a mitochondrial ATP‐binding cassette transporter (ABCB7), glutaredoxin 5 (GLRX5), as well as mitochondrial DNA deletions. Despite these known diverse causes, in a substantial portion of CSA cases a presumed genetic defect remains unknown.

Procedure

In the context of the recent discovery of SLC25A38 as a major novel cause, we systematically analyzed a large cohort of previously unreported CSA patients. Sixty CSA probands (28 females, 32 males) were examined for ALAS2, SLC25A38, PUS1, GLRX5, and ABCB7 mutations. SLC19A2 and mitochondrial DNA were only analyzed if characteristic syndromic features were apparent.

Results

Twelve probands had biallelic mutations in SLC25A38. Seven ALAS2 mutations were detected in eight sporadic CSA cases, two being novel. We also identified a novel homozygous null PUS1 mutation and novel mitochondrial DNA deletions in two patients with Pearson syndrome. No mutations were encountered in GLRX5, ABCB7, or SLC19A2.

Conclusions

The remaining undefined probands (43%) can be grouped according to gender, family, and clinical characteristics, suggesting novel X‐linked and autosomal recessive forms of CSA. Pediatr Blood Cancer 2010;54:273–278. © 2009 Wiley‐Liss, Inc.
Cytomegalovirus infection mimicking juvenile myelomonocytic leukemia showing hypersensitivity to granulocyte–macrophage colony stimulating factor
Authors: Moritake Hiroshi , Ikeda Toshio , Manabe Atsushi , Kamimura Sachiyo , Nunoi Hiroyuki
Published: September 2009

We describe an infant with cytomegalovirus (CMV) infection presenting as transient myeloproliferation resembling juvenile myelomonocytic leukemia (JMML). The patient fulfilled the international diagnostic criteria of JMML, including hypersensitivity to granulocyte–macrophage colony‐stimulating factor (GM‐CSF). Viral studies using serologic assays and polymerase chain reaction (PCR) were positive for CMV. Clinical symptoms disappeared and laboratory values returned to normal without specific treatment within 1 year. Follow‐up showing a decrease in viral titers suggested CMV infection as an etiologic factor for the development of myeloproliferative features. We conclude that the CMV infection transiently induced abnormal myelopoiesis in this infant. Pediatr Blood Cancer 2009; 53:1324–1326. © 2009 Wiley‐Liss, Inc.
Panton–Valentine leukocidin‐positive methicillin‐resistant Staphylococcus aureus infections in children with cancer
Authors: Srinivasan Ashok , Seifried Steven , Zhu Liang , Srivastava Deo K. , Flynn Patricia M. , Shenep Jerry L. , Bankowski Matthew J. , Hayden Randall T.
Published: September 2009

Background

New strains of methicillin‐resistant Staphylococcus aureus (MRSA) which frequently carry the Panton–Valentine leukocidin (PVL) genes have been recognized to cause invasive infections in otherwise healthy children and adults. However, the epidemiology of PVL‐positive MRSA infections has not been described in children or adults with cancer.

Procedure

The epidemiology of MRSA infections in patients with cancer was retrospectively studied from 2000 to 2007. Molecular typing was performed by polymerase chain reaction (PCR) for the detection of the PVL genes. Staphylococcus cassette chromosome (SCC) mec and spa typing was performed on all PVL‐positive isolates.

Results

A total of 88 MRSA isolates from clinically distinct infectious episodes were collected from 88 patients with cancer during the 8‐year study period. Infections were predominant in the skin and soft tissues (SSTI; P = 0.0003). PVL‐positive isolates, bearing the type IV SCCmec element, encoding the gene for methicillin resistance, increased significantly during this period (P = 0.043) and comprised 35 of 88 (40%) MRSA isolates. Of these 35 isolates, 32 belonged to spa type 8 and were USA300 genotype. Patients infected with PVL‐positive strains did not have more SSTI (P = 0.166) or bacteremia (P = 0.510) as compared to patients with PVL‐negative strains. A greater percentage of PVL‐positive isolates were susceptible to ciprofloxacin (P = 0.006).

Conclusions

PVL‐positive MRSA infections are not associated with a higher morbidity as compared to PVL‐negative MRSA infections in children with cancer. Pediatr Blood Cancer 2009; 53:1216–1220. © 2009 Wiley‐Liss, Inc.
Conidiobolomycosis in relapsed acute lymphoblastic leukemia
Authors: Radhakrishnan Nita , Sachdeva Anupam , Oberoi Jaswinder , Yadav Satya Prakash
Published: September 2009

Invasive fungal infections in immunocompromised children suffering from hematological malignancies have been a major cause of morbidity and mortality. In recent years fungi other than aspergillus and candida are gaining importance. These emerging fungal infections have distinct epidemiological features and management issues especially in immunocompromised patients. Here we report the isolation of Conidiobolus coronatus, a rarely reported zygomycetes infection in a patient suffering from acute lymphoblastic leukemia. Conidiobolus generally causes indolent infection in the sino‐respiratory tract. They are known to be angioinvasive and can disseminate. There is no consensus regarding appropriate antifungal treatment for Conidiobolus infection. Pediatr Blood Cancer 2009; 53:1321–1323. © 2009 Wiley‐Liss, Inc.
Allogeneic hematopoietic cell transplantation (allogeneic HCT) for treatment of pediatric Philadelphia chromosome‐positive acute lymphoblastic leukemia (ALL)
Authors: Burke Michael J. , Cao Qing , Trotz Barb , Weigel Brenda , Kumar Ashish , Smith Angela , Verneris Michael R.
Published: September 2009

Background

Allogeneic hematopoietic cell transplant (HCT) with best available donor for children with Philadelphia positive (Ph+) acute lymphoblastic leukemia (ALL) has previously been considered standard practice. Since the introduction of imatinib into the treatment of this disease, the role of allogeneic HCT is more uncertain.

Procedure

We investigated the impact of remission status, graft source, and imatinib use on transplant outcomes for 37 children with Ph+ ALL who received an allogeneic HCT at the University of Minnesota between 1990 and 2006. The median age at HCT was 7.47 (range; 1.4–16.4) years. Thirteen patients received imatinib therapy pre‐ and/or post‐HCT (imatinib group) and 24 patients, received either no imatinib (n = 23) or only post‐HCT relapse (n = 1) (non‐imatinib group).

Results

There was no difference in disease‐free survival (DFS) or relapse between the imatinib and non‐imatinib groups at 3 years (62%/15% vs. 53%/26%; P = 0.99; 0.81, respectively). There was no significant difference in transplant outcomes between matched related donor or unrelated donor (umbilical cord blood or matched unrelated marrow) recipients whereas patients receiving allogeneic HCT in first remission (CR1) had superior DFS and less relapse compared to patients transplanted in ≥CR2 (71%/16% vs. 29%/36%; P = 0.01; P = 0.05).

Conclusions

Based on this retrospective analysis at a single institution, the use of imatinib either pre‐ and/or post‐transplant does not appear to significantly impact outcomes for children with Ph+ ALL and allogeneic HCT with the best available donor should be encouraged in CR1. Pediatr Blood Cancer 2009; 53:1289–1294. © 2009 Wiley‐Liss, Inc.
Pharmacokinetics of daunorubicin and daunorubicinol in infants with leukemia treated in the interfant 99 protocol
Authors: Hempel Georg , Relling Mary V. , de Rossi Giulio , Stary Jan , De Lorenzo Paola , Valsecchi Maria Grazia , Barisone Elena , Boos Joachim , Pieters Rob
Published: September 2009

Background

There is an extreme paucity of pharmacokinetic data for anticancer agents in infants. Therefore, we aimed at characterizing the pharmacokinetics for daunorubicin in infants and examined their relationship to age, body weight, and body surface area.

Procedure

Leukemia patients treated according to the Interfant 99 protocol received 30 mg/m2 daunorubicin, with dose reduction to 3/4 for patients 6–12 months old and 2/3 for patients <6 months, respectively. Plasma samples from 21 patients (aged 0.05–1.88 years) were collected and analyzed for daunorubicin and daunorubicinol. Samples from 12 children (age 1.6–18.8 years), who received daunorubicin in an earlier investigation, were used for pharmacokinetic model building using the software NONMEM.

Results

Plasma concentration time profiles could be described using a two compartment model. Daunorubicin clearance was 43.9 L hr−1 m−2 ± 65% and central volume of distribution 16.4 L m−2 ± 46%, whereas apparent clearance of daunorubicinol was 19.1 L hr−1 m−2 ± 32% and apparent volume of distribution 228 L m−2 ± 80% (mean ± interindividual variability). No age‐dependency in any of the BSA‐normalized pharmacokinetic parameters was observed. Consequently, due to the empirical dose reduction in infants the overall exposure to daunorubicinol in infants was smaller than would be expected from older children. Patients aged <6 months experienced more infections in the induction phase than the group aged 6–12 months at diagnosis. Other toxicities were similar in both groups.

Conclusion

We observed no indication of an age‐dependency in the pharmacokinetics of daunorubicin. Pediatr Blood Cancer 2010;54:355–360. © 2009 Wiley‐Liss, Inc.
Clinical outcome in children with recurrent neuroblastoma treated with ABT‐751 and effect of ABT‐751 on proliferation of neuroblastoma cell lines and on tubulin polymerization in vitro
Authors: Meany Holly J. , Sackett Dan L. , Maris John M. , Ward Yvona , Krivoshik Andrew , Cohn Susan L. , Steinberg Seth M. , Balis Frank M. , Fox Elizabeth
Published: September 2009

Background

ABT‐751, an orally bioavailable sulfonamide, binds β‐tubulin to inhibit microtubule polymerization. We described response and event‐free survival (EFS) in children with neuroblastoma and other solid tumors receiving ABT‐751, assessed in vitro cytotoxicity of ABT‐751 and evaluated the effect of ABT‐751 on tubulin polymerization in peripheral blood mononuclear cells (PBMC) and pediatric tumor cell lines.

Procedure

Patients with neuroblastoma (n = 50) or other solid tumors (n = 26) enrolled on the ABT‐751 pediatric phase I and pilot trials were reviewed. The sulforhodamine B (SRB) and ACEA Real‐Time Cell Electronic Sensing (RT‐CES) assays were used to determine the in vitro cytotoxicity. Pharmacodynamic effects on tubulin polymerization/depolymerization were assessed by Western blot and confocal microscopy using antibodies specific for post‐translational modifications of polymerized tubulin.

Results

Forty‐five patients with neuroblastoma were evaluated for anti‐tumor response. No complete or partial responses were documented. The median EFS was 9.3 weeks for children with neuroblastoma and 3.3 weeks for children other solid tumors (P < 0.0001). The ABT‐751 IC50 was 0.6–2.6 mcM in neuroblastoma and 0.7–4.6 mcM in other solid tumor cell lines. Following drug exposure, polymerized tubulin decreased in a concentration‐ and time‐dependent manner in cell lines.

Conclusions

In children treated with ABT‐751, the EFS is longer in children with neuroblastoma as compared to other diagnoses. In vitro, ABT‐751 was cytotoxic at concentrations tolerable in children. Effects of ABT‐751 on polymerization and microtubule structure were time‐ and dose‐dependent but not dependent on tumor type. Pediatr Blood Cancer 2010; 54:47–54. © 2009 Wiley‐Liss, Inc.
The pediatric hydroxyurea phase III clinical trial (BABY HUG): Challenges of study design
Authors: Thompson Bruce W. , Miller Scott T. , Rogers Zora R. , Rees Renee C. , Ware Russell E. , Waclawiw Myron A. , Iyer Rathi V. , Casella James F. , Luchtman‐Jones Lori , Rana Sohail , Thornburg Courtney D. , Kalpatthi Ram V. , Barredo Julio C. , Brown R. Clark , Sarnaik Sharada , Howard Thomas H. , Luck Lori , Wang Winfred C.
Published: September 2009

Evidence of the laboratory benefits of hydroxyurea and its clinical efficacy in reducing acute vaso‐occlusive events in adults and children with sickle cell anemia has accumulated for more than 15 years. A definitive clinical trial showing that hydroxyurea can also prevent organ damage might support widespread use of the drug at an early age. BABY HUG is a randomized, double‐blind placebo‐controlled trial to test whether treating young children ages 9–17 months at entry with a liquid preparation of hydroxyurea (20 mg/kg/day for 2 years) can decrease organ damage in the kidneys and spleen by at least 50%. Creation of BABY HUG entailed unique challenges and opportunities. Although protection of brain function might be considered a more compelling endpoint, preservation of spleen and renal function has clinical relevance, and significant treatment effects might be discernable within the mandated sample size of 200. Concerns about unanticipated severe toxicity and burdensome testing and monitoring requirements were addressed in part by an internal Feasibility and Safety Pilot Study, the successful completion of which was required prior to enrolling a larger number of children on the protocol. Concerns over recruitment of potentially vulnerable subjects were allayed by inclusion of a research subject advocate, or ombudsman. Finally, maintenance of blinding of research personnel was aided by inclusion of an unblinded primary endpoint person, charged with transmitting endpoint data and monitoring blood work locally for toxicity (ClinicalTrials.gov number, NCT00006400). Pediatr Blood Cancer 2010;54:250–255. © 2009 Wiley‐Liss, Inc.
Tree fruit IPM programs in the western United States: the challenge of enhancing biological control through intensive management
Authors: Jones Vincent P , Unruh Thomas R , Horton David R , Mills Nicholas J , Brunner Jay F , Beers Elizabeth H , Shearer Peter W
Published: September 2009

The seminal work of Stern and his coauthors on integrated control has had a profound and long‐lasting effect on the development of IPM programs in western orchard systems. Management systems based solely on pesticides have proven to be unstable, and the success of IPM systems in western orchards has been driven by conservation of natural enemies to control secondary pests, combined with pesticides and mating disruption to suppress the key lepidopteran pests. However, the legislatively mandated changes in pesticide use patterns prompted by the Food Quality Protection Act of 1996 have resulted in an increased instability of pest populations in orchards because of natural enemy destruction. The management system changes have made it necessary to focus efforts on enhancing biological control not only of secondary pests but also of primary lepidopteran pests to help augment new pesticides and mating disruption tactics. The new management programs envisioned will be information extensive as well as time sensitive and will require redesign of educational and outreach programs to be successful. The developing programs will continue to use the core principles of Stern and his co‐authors, but go beyond them to incorporate changes in society, technology and information transfer, as needed. Copyright © 2009 Society of Chemical Industry
Seasonal evolution of boundary‐layer turbulence measured by aircraft during the AMMA 2006 Special Observation Period
Authors: Saïd F. , Canut G. , Durand P. , Lohou F. , Lothon M.
Published: September 2009

During the African Monsoon Multidisciplinary Analysis (AMMA) field campaign, the ATR research aircraft made observations of fluxes and thermodynamics during three 15‐day periods, which allowed the seasonal evolution of the atmospheric boundary‐layer (ABL) characteristics to be monitored before and after the monsoon onset. As expected, temperature and humidity showed a contrast between dry warm conditions and moister cooler conditions from one period to the other. Most of the time, the wind blew from the west (northwesterly to southwesterly) in the ABL and from the east in the free troposphere. Following rainfall events occuring in July and August, surface sensible heat flux decreased and evaporation increased while the momentum flux remained large in the entire boundary layer, whatever the period. The aim of this paper is to characterize turbulence in terms of fluxes and length‐scales for ABLs that exhibit particular characteristics relative to (i) entrainment at the top, (ii) wind rotation at the interface between the monsoon and the Saharan air layer and (iii) seasonal variability. In spite of the poorer accuracy of the turbulent flux estimations at the top of the ABL, the flux profiles were observed to increase or decrease linearly with altitude which enabled accurate estimates of entrainment flux ratios. It was found that the moisture flux distribution in the ABL was governed by top‐down processes during the driest period and a mixture of top‐down and bottom‐up processes during the monsoon period. Significant differences in turbulence length‐scales were also highlighted. Copyright © 2009 Royal Meteorological Society
Nonequivalent Effects of Diverse LogP Algorithms in Three QSAR Studies
Authors: de Melo Eduardo Borges , Ferreira Márcia Miguel Castro
Published: September 2009

Despite of the availability and facility of accessing several algorithms for calculation of LogP in QSA(P)R studies, articles typically do not describe the selection procedure for the method used. Therefore, three studies to verify the influence of different LogP algorithms on building QSAR models were performed. Two QSAR data sets from the literature (forty‐two tricyclic phtalimide inhibitors of HIV‐integrase and fourty‐six TIBO derivatives inhibitors of HIV‐reverse transcriptase) were used together with LogP calculated by thirteen algorithms, and several regression models were constructed and compared. A new QSAR study for 4,5‐dihydroxypyrimidine carboxamides inhibitors of HIV‐1 integrase was also performed. The explained and predicted variance, results from external validation, leave‐N‐out cross‐validation and y‐randomization test were analyzed for all models from the three data sets. Despite the same physicochemical meaning, LogP's calculated by distinct methods may show different levels of contribution to the model. This observation comes out from the comparison of validated models. These results indicate that the arbitrary choice of one specific algorithm for LogP calculation, as is usual in QSA(P)R studies , does not necessarily lead to the highest quality model for the analyzed data set.