bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnesium oxide microspheres as a novel solid‐phase extraction sorbent for the determination of benzo[a]pyrene in environmental water samples
Authors: Jin Jing , Zhang Zhiping , Wang Jincheng , Qi Peipei , Chen Jiping
Published: May 2010

Magnesium oxide microspheres were developed as a novel SPE sorbent for the determination of benzo[a]pyrene (BaP), one of the most potent carcinogenic agents, in environmental water samples. The parameters controlling the extraction efficiency, such as elution volume, flow rate, pH values, and breakthrough volume, were investigated in detail. Considering the facile preparation and satisfying recovery, a corresponding analytical method has been developed to determine the concentration of BaP in real tap water, river water, and seawater. The recoveries for the spiked BaP were excellent (94–101%).
Simultaneous determination of substrate and product in the process of preparation of valienamine by capillary zone electrophoresis
Authors: Wei Xiao‐Dong , Zhao Wen‐Jie , Gu Min , Zhao Bo , Yao Rong‐Ying
Published: May 2010

A simple and rapid CZE method was established for the simultaneous determination of valienamine, acarbose and validamycin A, using a 20‐kV CZE with the detection wavelength of 193 nm and 50 mM phosphoric acid–20 mM Tris (pH 5.3) as a running buffer. The calibration curves of valienamine, acarbose, and validamycin A showed a good linear relationship at a concentration range of 5–1000 μg/mL. The detection limits of valienamine, acarbose, and validamycin A were 0.3, 0.6, and 0.6 μg/mL, respectively, and the average recoveries of each of the above were 99.9, 99.5, and 100.3%. The method has been successfully applied for simultaneous determination of substrate and product in the process of preparation of valienamine.
Small tourism business research change and evolution
Authors: Morrison Alison , Carlsen Jack , Weber Paul
Published: May 2010

The paper critically reflects on key knowledge contributions that coalesce to inform contemporary understanding of the phenomenon of small tourism business. The purpose is to scrutinise change and evolution in perspectives and how these impact on what knowledge is disclosed and what is not. Conventionally accepted wisdom is challenged, indoctrinated presuppositions are questioned, and research methodological advancements are offered. This is achieved through a comprehensive review and critical‐reflective analysis of key academic contributions spanning a period of approximately 35 years. The value is to stimulate criticality relative to what constitutes ‘truth’ within the given context and to inspire fresh research perspectives. Conclusions are drawn regarding future research directions. Furthermore, informed by thorough analysis of the content of the paper, five guiding research principles provide an appropriate conclusion. Copyright © 2010 John Wiley & Sons, Ltd.
Institutionally based health care workers' exposure to traumatogenic events: Systematic review of PTSD presentation
Authors: Robertson Noelle , Perry Andrew
Published: May 2010

This review sought to identify published evidence for the presentation of posttraumatic stress disorder (PTSD) symptoms in institutionally based health care workers. The databases Medline, Psycinfo, PILOTS, CINAHL (R), EMBASE, and ISI Web of Science were searched in a systematic manner eliciting 9 quantitative studies. Presentation of PTSD among such workers appears comparable to data reported for emergency services staff. The authors discuss some of the theoretical debates underpinning the research as well as methodological weaknesses that temper the strength of conclusions drawn.
Accurate Elemental Analysis of Metal‐Containing Polymer Latexes Using ICP‐Optical Emission Spectrometry
Authors: Vogel Nicolas , Hauser Christoph P. , Schuller Kilian , Landfester Katharina , Weiss Clemens K.
Published: May 2010

The use of ICP‐OES to determine the metal content of metal‐complex‐containing colloidal dispersions is explored. Colloidal dispersions containing a defined amount of metal complex were produced by miniemulsion polymerization. It was found that simple ICP‐OES measurements yielded apparent metal concentrations significantly below the expected value. To examine the behavior of the colloidal dispersions in the ICP spectrometer, a systematic study on measurement conditions was performed. It was found that the addition of a surfactant to both colloidal dispersions and standards led to measured metal contents close to the theoretical value. Most reliable results were obtained using SDS in concentrations above the cmc.

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Molecular dynamics of the blood–testis barrier components during murine spermatogenesis
Authors: Chihara Masataka , Otsuka Saori , Ichii Osamu , Hashimoto Yoshiharu , Kon Yasuhiro
Published: May 2010

The blood–testis barrier (BTB) separates the seminiferous epithelium into the adluminal and basal compartments. During murine spermatogenesis, preleptotene/leptotene spermatocytes migrate from the basal to the adluminal compartment through the BTB during stages VIII–IX. In the present study, we focused on the tight junction (TJ) molecules and analyzed their spatiotemporal expression during the murine seminiferous epithelial cycle. Structural analysis revealed that the principal components of the BTB, for example, claudin‐3, claudin‐11, occludin, and zonula occludens‐1 (ZO‐1), were localized at the basal and luminal sides of the preleptotene/leptotene spermatocytes during the migration stages (VIII–IX). Although we detected claudin‐11, occludin, and ZO‐1 throughout spermatogenesis, claudin‐3 was only detected during stages VI–IX. Quantitative PCR using dissected seminiferous tubules from three stages (Early: II–VI, Middle: VII–VIII, Late: IX–I) clarified that the mRNA levels of TJ molecules were not correlated with the histoplanimetrical protein levels during spermatogenesis. Additionally, tubulobulbar complexes, considered to be involved in the internalization of TJ, were observed at the BTB site. Furthermore, a significant reduction in the mRNA levels of genes for the degradation of occludin (Itch) and endocytic recycling (Rab13) were observed during the Late and Middle stages, respectively. Therefore, we hypothesized that the lag between mRNA and protein expression of TJ molecules may be due to posttranslational modulation, for example, tubulobulbar complexes and endocytic recycling processes. In conclusion, these findings indicate that the integrity of the BTB is maintained throughout spermatogenesis, and the stage‐specific localization of claudin‐3 protein plays an important role in regulating BTB permeability. Mol. Reprod. Dev. 77: 630–639, 2010. © 2010 Wiley‐Liss, Inc.
Reproducibility of quantitative magnetization‐transfer imaging parameters from repeated measurements
Authors: Levesque Ives R. , Sled John G. , Narayanan Sridar , Giacomini Paul S. , Ribeiro Luciana T. , Arnold Douglas L. , Pike G. Bruce
Published: May 2010

Quantitative magnetization‐transfer imaging methods provide in vivo estimates of parameters of the two‐pool model for magnetization‐transfer in tissue. The goal of this study was to evaluate the reproducibility of quantitative magnetization‐transfer imaging parameter estimates in healthy subjects. Magnetization‐transfer–weighted and T1 relaxometry data were acquired in five healthy subjects at multiple time points, and the variability of the resulting fitted magnetization‐transfer parameters was evaluated. The impact of subsampling the magnetization‐transfer data and correcting field inhomogeneities was also evaluated. The key parameters measured in this study had an average variability, across time points, of 4.7% for the relative size of the restricted pool (F), 7.3% for the forward exchange constant (kf), 1.9% for the free pool spin‐lattice relaxation constant (R1f), 4.5% for the T2 of the free pool (T2f), and 2.3% for the T2 of the restricted pool (T2r). Our findings show that serial quantitative magnetization‐transfer imaging experiments can be performed reliably, with good reproducibility of the model parameter estimates, and demonstrate the reproducibility of acquisition schemes with fewer magnetization‐transfer contrasts. This establishes the feasibility of this technique for monitoring patients affected by degenerative white matter diseases while providing critical data to estimate the statistical power of such studies. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Quantitative sodium imaging with a flexible twisted projection pulse sequence
Authors: Lu Aiming , Atkinson Ian C. , Claiborne Theodore C. , Damen Frederick C. , Thulborn Keith R.
Published: May 2010

The quantification of sodium MR images from an arbitrary intensity scale into a bioscale fosters image interpretation in terms of the spatially resolved biochemical process of sodium ion homeostasis. A methodology for quantifying tissue sodium concentration using a flexible twisted projection imaging sequence is proposed that allows for optimization of tradeoffs between readout time, signal‐to‐noise ratio efficiency, and sensitivity to static field susceptibility artifacts. The gradient amplitude supported by the slew rate at each k‐space radius regularizes the readout gradient waveform design to avoid slew rate violation. Static field inhomogeneity artifacts are corrected using a frequency‐segmented conjugate phase reconstruction approach, with field maps obtained quickly from coregistered proton imaging. High‐quality quantitative sodium images have been achieved in phantom and volunteer studies with real isotropic spatial resolution of 7.5 × 7.5 × 7.5 mm3 for the slow T2 component in ∼8 min on a clinical 3‐T scanner. After correcting for coil sensitivity inhomogeneity and water fraction, the tissue sodium concentration in gray matter and white matter was measured to be 36.6 ± 0.6 μmol/g wet weight and 27.6 ± 1.2 μmol/g wet weight, respectively. Magn Reson Med 63:1583–1593, 2010. © 2010 Wiley‐Liss, Inc.
Assessment of synovitis in the osteoarthritic knee: Comparison between manual segmentation, semiautomated segmentation, and semiquantitative assessment using contrast‐enhanced fat‐suppressed T1‐weighted MRI
Authors: Fotinos‐Hoyer Amber Kassel , Guermazi Ali , Jara Hernán , Eckstein Felix , Ozonoff Al , Khard Hussain , Norbash Alexander , Bohndorf Klaus , Roemer Frank W.
Published: May 2010

Osteoarthritic joints regularly exhibit synovitis, which is ideally assessed on contrast‐enhanced MRI. Manual segmentation is the reference standard for volumetric analysis but is labor intensive. The aim was to evaluate alternative semiautomated approaches of targeted thresholding and gaussian deconvolution. Volumetric and semiquantitative synovitis assessment was compared in addition. Thirty‐two knees with osteoarthritis were scanned on a 1.5‐T system. Synovitis volumes were plotted against each other and distributions fit with linear functions. The relationship between semiquantitative scores and synovitis volumes was assessed using Spearman's correlation coefficient. Semiautomated volume measurement was more time efficient than manual segmentation and showed a high correlation with manual analysis (R2 = 0.88 and 0.82). Manual segmentation was correlated with summed and with maximum semiquantitative synovitis scores (ρ = 0.71 and 0.47). In conclusion, semiautomated analysis provides comparable quantitative results when compared to manual segmentation but is approximately five times more time efficient. Semiquantitative assessment adds anatomic information on synovitis distribution. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
A simple method for rectified noise floor suppression: Phase‐corrected real data reconstruction with application to diffusion‐weighted imaging
Authors: Prah Douglas E. , Paulson Eric S. , Nencka Andrew S. , Schmainda Kathleen M.
Published: May 2010

Diffusion‐weighted MRI is an intrinsically low signal‐to‐noise ratio application due to the application of diffusion‐weighting gradients and the consequent longer echo times. The signal‐to‐noise ratio worsens with increasing image resolution and diffusion imaging methods that use multiple and higher b‐values. At low signal‐to‐noise ratios, standard magnitude reconstructed diffusion‐weighted images are confounded by the existence of a rectified noise floor, producing poor estimates of diffusion metrics. Herein, we present a simple method of rectified noise floor suppression that involves phase correction of the real data. This approach was evaluated for diffusion‐weighted imaging data, obtained from ethanol and water phantoms and the brain of a healthy volunteer. The parameter fits from monoexponential, biexponential, and stretched‐exponential diffusion models were computed using phase‐corrected real data and magnitude data. The results demonstrate that this newly developed simple approach of using phase‐corrected real images acts to reduce or even suppress the confounding effects of a rectified noise floor, thereby producing more accurate estimates of diffusion parameters. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Phase‐based arterial input function measurements for dynamic susceptibility contrast MRI
Authors: Bleeker Egbert J. W. , van Buchem Mark A. , Webb Andrew G. , van Osch Matthias J. P.
Published: May 2010

In dynamic susceptibility contrast perfusion MRI, arterial input function (AIF) measurements using the phase of the MR signal are traditionally performed inside an artery. However, phase‐based AIF selection is also feasible in tissue surrounding an artery such as the middle cerebral artery, which runs approximately perpendicular to B0 since contrast agents also induce local field changes in tissue surrounding the artery. The aim of this study was to investigate whether phase‐based AIF selection is better performed in tissue just outside the middle cerebral artery than inside the artery. Additionally, phase‐based AIF selection was compared to magnitude‐based AIF selection. Both issues were studied theoretically and using numerical simulations, producing results that were validated using phantom experiments. Finally, an in vivo experiment was performed to illustrate the feasibility of phase‐based AIF selection. Three main findings are presented: first, phase‐based AIF selections are better made in tissue outside the middle cerebral artery, rather than within the middle cerebral artery, since in the latter approach partial‐volume effects affect the shape of the estimated AIF. Second, optimal locations for phase‐based AIF selection are similar for different clinical dynamic susceptibility contrast MRI sequences. Third, phase‐based AIF selection allows more locations in tissue to be chosen that show the correct AIF than does magnitude‐based AIF selection. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Optimized inversion recovery sequences for quantitative T1 and magnetization transfer imaging
Authors: Li Ke , Zu Zhongliang , Xu Junzhong , Janve Vaibhav A. , Gore John C. , Does Mark D. , Gochberg Daniel F.
Published: May 2010

Inversion recovery sequences that vary the inversion time (ti) have been employed to determine T1 and, more recently, quantitative magnetization transfer parameters. Specifically, in previous work, the inversion recovery pulse sequences varied ti only while maintaining a constant delay (td) between repetitions. T1 values were determined by fitting to a single exponential function, and quantitative magnetization transfer parameters were then determined by fitting to a biexponential function with an approximate solution. In the current study, new protocols are employed, which vary both ti and td and fit the data with minimal approximations. Cramer‐Rao lower bounds are calculated to search for acquisition schemes that will maximize the precision efficiencies of T1 and quantitative magnetization transfer parameters. This approach is supported by Monte Carlo simulations. The optimal T1 schemes are verified by measurements on MnCl2 samples. The optimal quantitative magnetization transfer schemes are confirmed by measurements on a series of cross‐linked bovine serum albumin phantoms of varying concentrations. The effects of varying the number of sampling data points are also explored, and a rapid acquisition scheme is demonstrated in vivo. These new optimized quantitative imaging methods provide an improved means for determining T1 and magnetization transfer parameter values compared to previous inversion recovery based methods. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
3D undersampled golden‐radial phase encoding for DCE‐MRA using inherently regularized iterative SENSE
Authors: Prieto Claudia , Uribe Sergio , Razavi Reza , Atkinson David , Schaeffter Tobias
Published: May 2010

One of the current limitations of dynamic contrast‐enhanced MR angiography is the requirement of both high spatial and high temporal resolution. Several undersampling techniques have been proposed to overcome this problem. However, in most of these methods the tradeoff between spatial and temporal resolution is constant for all the time frames and needs to be specified prior to data collection. This is not optimal for dynamic contrast‐enhanced MR angiography where the dynamics of the process are difficult to predict and the image quality requirements are changing during the bolus passage. Here, we propose a new highly undersampled approach that allows the retrospective adaptation of the spatial and temporal resolution. The method combines a three‐dimensional radial phase encoding trajectory with the golden angle profile order and non‐Cartesian Sensitivity Encoding (SENSE) reconstruction. Different regularization images, obtained from the same acquired data, are used to stabilize the non‐Cartesian SENSE reconstruction for the different phases of the bolus passage. The feasibility of the proposed method was demonstrated on a numerical phantom and in three‐dimensional intracranial dynamic contrast‐enhanced MR angiography of healthy volunteers. The acquired data were reconstructed retrospectively with temporal resolutions from 1.2 sec to 8.1 sec, providing a good depiction of small vessels, as well as distinction of different temporal phases. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
GRAPPA operator for wider radial bands (GROWL) with optimally regularized self‐calibration
Authors: Lin Wei , Huang Feng , Li Yu , Reykowski Arne
Published: May 2010

A self‐calibrated parallel imaging reconstruction method is proposed for azimuthally undersampled radial dataset. A generalized auto‐calibrating partially parallel acquisition (GRAPPA) operator is used to widen each radial view into a band consisting of several parallel lines, followed by a standard regridding procedure. Self‐calibration is achieved by regridding the central k‐space region, where Nyquist criterion is satisfied, to a rotated Cartesian grid. During the calibration process, an optimal Tikhonov regularization factor is introduced to reduce the error caused by the small k‐space area of the self‐calibration region. The method was applied to phantom and in vivo datasets acquired with an eight‐element coil array, using 32‐64 radial views with 256 readout samples. When compared with previous radial parallel imaging techniques, GRAPPA operator for wider radial bands (GROWL) provides a significant speed advantage since calibration is carried out using the fully sampled k‐space center. A further advantage of GROWL is its applicability to arbitrary‐view angle ordering schemes. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
23Na and 2H magnetic resonance studies of osteoarthritic and osteoporotic articular cartilage
Authors: Keinan‐Adamsky Keren , Shinar Haddasah , Shabat Shay , Brin Yaron S. , Nyska Meir , Navon Gil
Published: May 2010

In this study, the short component of the 23Na T2 (T2f) and the 23Na and 2H quadrupolar interactions (νQ) were measured in bone‐cartilage samples of osteoarthritic (OA) and osteoporotic (OP) patients. 23Na νQ was found to increase in osteoarthritic articular cartilage relative to controls. Similar results were found in bovine cartilage following proteoglycan (PG) depletion, a condition that prevails in osteoarthritis. 23Na νQ and 1/T2f for articular cartilage obtained from osteoporotic patients were significantly larger than for control and osteoarthritic cartilage. Decalcification of both human and bovine articular cartilage resulted in an increase of 23Na νQ and 1/T2f, showing the same trend as the osteoporotic samples. Differences in the ratio of the intensity of the large 2H splitting to that of the small one in the calcified zone were also observed. In osteoporosis, this ratio was twice as large as that obtained for both control and osteoarthritic samples. The 2H and 23Na results can be interpreted as due to sodium ions and water molecules filling the void created by the calcium depletion and to calcium ions being located in close association with the collagen fibers. To the best of our knowledge, this is the first study reporting differences of NMR parameters in cartilage of osteoporotic patients. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Stabilization of jump linear systems with mode‐dependent time‐varying delays
Authors: Zhao Xudong , Zeng Qingshuang
Published: May 2010

This paper deals with the stabilization problems for a class of Markovian jump systems with time delays which are time varying and depending on system mode. Following the recent study on the class of systems, improved sufficient condition for stochastic stability of the underlying systems is derived by constructing a different Lyapunov–Krasovskii functional. Basing on this new criterion, a stabilization algorithm through memory state feedback controller is designed. Illustrative numerical examples are provided to demonstrate the effectiveness of the proposed approaches. Copyright © 2010 John Wiley & Sons, Ltd.
Intracavitary cisplatin therapy for pediatric malignancies
Authors: Katzenstein Howard M. , Petricca Sarah , Ricketts Richard , Wasilewski‐Masker Karen , Powell Christie , Rapkin Louis , George Bradley , Woods William G. , Olson Thomas A.
Published: May 2010

Background

Local control is essential for the successful treatment of pediatric solid tumors. Complete excision is often not possible and local control therapies are limited. Intracavitary cisplatin (IC‐CDDP) may be utilized to supplement local control. The aim of the study was to determine the toxicity and efficacy of locally instilled intracavitary cisplatin in patients with recurrent tumors in closed body cavities.

Procedure

From 2001 to 2009, 12 patients (1–20 years) with recurrent or unresectable malignant tumors were treated with IC‐CDDP. Nine had pulmonary lesions. Three patients had abdominal tumors. CDDP (200 mg/m2) was instilled by chest tube or Tenckhoff catheter. Patients were shifted every 15–30 min to allow distribution. After 4 hr, residual was drained by gravity. In 10/13 courses, sodium thiosulfate (STS) was administered to prevent nephrotoxicity. Three other patients received amifostine.

Results

Malignant pleural effusions resolved in 5/7 patients. This response was temporary in three patients. No patients had ascites prior to treatment. Three patients are alive and disease‐free, 18 months, 4 years, and 6 years from treatment. They also had surgery and chemotherapy. Transient renal toxicity was noted in most patients. One patient, treated with amifostine, had persistent renal dysfunction.

Conclusions

IC‐CDDP was effective in treating malignant pleural effusions and may be a palliative option for refractory disease. Long‐term survival was achieved in two patients, treated at first diagnosis. The benefit of IC‐CDDP in these patients is difficult to assess. Renal dysfunction is usually mild, and typically resolves, but warrants preventive measures with IC‐CDDP therapy. Pediatr Blood Cancer. 2010;55:452–456. © 2010 Wiley‐Liss, Inc.
Impact of continuous renal replacement therapy on oxygenation in children with acute lung injury after allogeneic hematopoietic stem cell transplantation
Authors: Elbahlawan Lama , West Nancy K. , Avent Yvonne , Cheng Cheng , Liu Wei , Barfield Raymond C. , Jones Deborah P. , Rajasekaran Surender , Morrison R. Ray
Published: May 2010

Background

Acute lung injury (ALI) continues to carry a high mortality rate in children after allogeneic hematopoietic stem cell transplant (HSCT). Continuous renal replacement therapy (CRRT) is often used for these patients for various indications including renal failure and fluid overload, and may have a beneficial effect on oxygenation and survival. Therefore, we sought to determine the effect of CRRT on oxygenation in mechanically ventilated pediatric allogeneic HSCT patients with ALI, and to document survival to intensive care unit discharge in this at‐risk population receiving both mechanical ventilation and CRRT.

Procedure

Retrospective analysis of a pediatric allogeneic HSCT cohort admitted to intensive care unit of a single pediatric oncology center from 1994 to 2006 who received CRRT during a course of mechanical ventilation for ALI.

Results

Thirty post‐HSCT mechanically ventilated children with ALI who underwent CRRT were included. There was a significant improvement in PaO2/FiO2 with median increase of 31 and 43 in the 24 and 48 hr intervals after initiation of CRRT compared with the 24 hr interval before CRRT (P = 0.0008 and 0.0062, respectively). This improvement in PaO2/FiO2 correlated significantly with reduction of fluid balance achieved after initiation of CRRT (P = 0.0001). There was a trend not reaching statistical significance in improvement in mean airway pressure 48 hr after CRRT in survivors compared to non‐survivors.

Conclusions

CRRT improved oxygenation in mechanically ventilated pediatric allogeneic HSCT patients with ALI. Pediatr Blood Cancer. 2010;55:540–545. © 2010 Wiley‐Liss, Inc.
Non‐metastatic osteosarcoma of the extremities in children aged 5 years or younger
Authors: Abate Massimo Eraldo , Longhi Alessandra , Galletti Stefano , Ferrari Stefano , Bacci Gaetano
Published: May 2010

Background

The occurrence of high‐grade osteosarcoma is rare in children aged 5 years or younger and only limited series or case reports have been described.

Methods

The records of patients aged 5 years or younger with non‐metastatic high‐grade osteosarcoma of the extremities treated with surgery and adjuvant or neo‐adjuvant chemotherapy at Rizzoli Institute between 1972 and 1999 were retrospectively evaluated in relation to gender, primary tumor site, histological subtype, surgical treatment, chemotherapy‐induced tumor necrosis, 5‐ and 10‐year event‐free survival (EFS), and rate of local recurrence. Data were compared to patients aged 6–40 years entered with the same diagnosis and over the same time interval.

Results

Data from 20 patients were collected. Comparing these data with those from 1,106 patients 6–40 years of age only two main differences resulted: the younger group showed a higher rate for fibroblastic subtype (P < 0.01) and for amputation surgery (P < 0.01). Among the two groups, no statistical difference was observed for the 5‐year EFS (60% vs. 53.8%; P = 0.6) and 10‐year EFS (60% vs. 52.1%; P = 0.5). The rate of local recurrence was 5.0% and 5.4%.

Conclusions

These findings suggest that in non‐metastatic osteosarcoma of the extremities outcome and clinical characteristics are similar among children 5 years of age or younger and older patients. However, in the younger group we have observed a significant higher rate of fibroblastic subtype as well as a significant higher rate of mutilating surgery. Pediatr Blood Cancer. 2010;55:652–654. © 2010 Wiley‐Liss, Inc.
Imaging in pediatric patients: Time to think again about surveillance
Authors: Lee Chong Amy , Grant Ronald M. , Ahmed Bilal A. , Thomas Karen E. , Connolly Bairbre L. , Greenberg Mark
Published: May 2010

Background

Despite concerns regarding ionizing radiation exposures from diagnostic imaging procedures in pediatric patients, many are deemed unavoidable or even mandated by treatment protocols. A prior review at our institution found patients with lymphoma had a higher median cumulative radiation exposure (191 mSv) versus other oncology subgroups (61 mSv).

Purpose

Estimations of cumulative diagnostic radiation exposures were tabulated for 5 years from the first diagnostic scan for 30 consecutive lymphoma patients diagnosed in 2001. Each individual imaging procedure was reviewed and classified as protocol mandated or discretionary (for disease surveillance, good patient care or radiologist request).

Results

Almost all patients (28/29) received chemotherapy; one had surgery only. Individual cumulative radiation exposures ranged from 10 to 642 mSv. Over 5 years, 690 procedures were performed; 303 (44%) X‐rays, 203 (29%) CTs, 157 (23%) radionucleotide, and 27 (4%) interventional procedures. Of these, 238 (34%) were protocol required and 452 (66%) discretionary (224 as part of good patient care for a co‐morbid illness and 228 for evaluation of possible disease progression/surveillance). A total of 86/217 (40%) studies (including 43 CTs and 38 radionucleotide scans) were performed when the recurrence risk was low (>2 years off therapy).

Conclusions

The majority of ionizing radiation procedures in this lymphoma cohort were discretionary. Given the excellent outcome of this group and the long‐term risks; rational use of discretionary surveillance procedures is necessary. Guidelines for the appropriate use of surveillance imaging based on probability of risk recurrence must be developed in order to minimize ionizing radiation exposure. Pediatr Blood Cancer. 2010;55:407–413. © 2010 Wiley‐Liss, Inc.
A new improved high‐order theory for analysis of free vibration of sandwich panels
Authors: Jam J. E. , Eftari B. , Taghavian S. H.
Published: May 2010

A new improved high‐order theory is presented to investigate the dynamic behavior of sandwich panels with flexible core. Shear deformation theory is used for the face sheets, whereas the three‐dimensional elasticity theory is used for the core. Displacements in the core are assumed as polynomial with unknown coefficients. Inertia forces, moments of inertia and shear deformations in the core, and the face sheets are taken into consideration. Unlike the previous improved theory, the in‐plane normal and shear stresses in the core are considered. The governing equations and the boundary conditions are derived by Hamilton's principle. Closed form solution is achieved using the Navier method and solving the eigenvalues. The numerical results of present analysis compared with the available results in the literature. It indicates that the present new modified theory is more accurate than the other developed theories for sandwich panels. In this study, the variation of the nondimensional natural frequency with respect to the various parameters is presented. POLYM. COMPOS., 31:2042–2048, 2010. © 2010 Society of Plastics Engineers
Second trimester serum predictors of preterm birth in a population‐based sample of low‐risk pregnancies
Authors: Jelliffe‐Pawlowski Laura L. , Baer Rebecca J. , Currier Robert J.
Published: May 2010

Objective

To examine the relationship between typically collected second trimester maternal serum biomarkers and preterm birth among pregnancies without intrauterine‐growth‐retardation or other specific risk factors.

Methods

Included were 102 861 singleton pregnancies without specific risks that resulted in the live birth of an infant of normal birth weight for gestational age without aneuploidy or a neural tube defect. Logistic binomial regression analyses were used to estimate the relative risk (RR) of giving birth preterm among pregnancies with an abnormal level of alpha‐fetoprotein (AFP), human chorionic gonatotropin (hCG), and/or unconjugated estriol (uE3) compared to pregnancies with normal biomarker levels.

Results

When compared to pregnancies with normal levels of AFP, hCG, and uE3, pregnancies with elevated levels of any biomarker [multiple of the median (MoM) ≥ 2.0] were at an increased risk for preterm birth regardless of preterm grouping (RRs 1.3–5.4). Risks for preterm birth tended to increase substantially when at least two biomarkers were elevated (RRs 2.2–18.7).

Conclusion

The results suggest that second trimester maternal serum biomarkers may help identify pregnancies at increased risk for preterm birth when no other identified risks are present. Data indicates that biomarkers may be particularly predictive of early preterm birth. Copyright © 2010 John Wiley & Sons, Ltd.
The role of molecular microsatellite identity testing to detect sampling errors in prenatal diagnosis
Authors: Winsor E. J. T. , Akoury H. , Chitayat D. , Steele L. , Stockley T. L.
Published: May 2010

Objective

The objective was to determine the risk of sampling error in amniocentesis and chorionic villus sampling (CVS) in singleton and multiple pregnancies. Data from this and other published studies were used to discuss current practice guidelines for molecular identity testing.

Method

Clinical and laboratory records of all patients undergoing molecular‐based identity testing in our clinical laboratory from July 2002 until March 2008 were reviewed. DNA microsatellite testing was performed to determine zygosity in multiple pregnancies and maternal cell contamination (MCC) in both singleton and multiple pregnancies.

Results

MCC was detected in 6/148 (4%) CVS and 1/87 (1%) amniotic fluids from singleton pregnancies. In two of the CVS, only maternal cells were found. In 2/24 (8%) twin pregnancies, the same fetus was tested twice. In a total of 285 pregnancies (235 singleton, 24 twin, 26 with ≥ 3 fetuses), without molecular identity testing, four women would have received erroneous results.

Conclusion

Current guidelines recommend molecular identity testing for MCC in conjunction with molecular diagnostic testing, but not for cytogenetic testing. No published guidelines were found for zygosity testing in multiple pregnancies. We suggest that identity testing be considered for all prenatal testing of multiple pregnancies, especially if CVS is performed. Copyright © 2010 John Wiley & Sons, Ltd.
Surfactant‐assisted processing of polyimide/multiwall carbon nanotube nanocomposites for microelectronics applications
Authors: Tang Qing‐Yuan , Chan Yan‐Cheong , Wong Ning‐Bew , Cheung Rebecca
Published: May 2010

The dispersion and stability of carbon nanotubes (CNTs) inside a polymer matrix, especially with a high CNT content, are still big challenges. Moreover, the interaction between CNTs and the polymer matrix should be strong enough to improve the mechanical properties. The efficient dispersion of CNTs is essential for the formation of a uniform distribution of a CNT network in a polymer composite. Polyimide/multiwall CNT nanocomposites were synthesized by in situ polymerization with the aid of a surfactant. A Fourier transform infrared spectroscopy study proved that the surfactant did not hamper the polymerization of the polyimide. The microstructure, storage modulus and electrical conductivity of the nanocomposites were improved using a particular amount of the surfactant. Environmental stability test results showed that the polyimide with 1 wt% of CNTs produced with the aid of the surfactant possessed excellent reliability in high‐temperature and high‐humidity environments. Surfactants were successfully used to obtain fine‐structure polyimide/CNT nanocomposites by in situ polymerization. The enhancement of the mechanical properties was attributed to the incorporation of the surfactant. A percolation of electrical conductivity could be achieved with 1 wt% of CNTs. Copyright © 2010 Society of Chemical Industry
The carbonization of colloidal polyaniline nanoparticles to nitrogen‐containing carbon analogues
Authors: Stejskal Jaroslav , Trchová Miroslava , Hromádková Jir̆ina , Kovár̆ová Jana , Kalendová Andrea
Published: May 2010

The carbonization of nanostructures afforded by conducting polymers represents a new route to the preparation of functional nanostructured carbons. The exposure of colloidal polyaniline particles stabilized with poly(N‐vinylpyrrolidone) or silica nanoparticles at 650 °C in inert atmosphere led, in both cases, to nitrogen‐containing carbonaceous materials with specific surface areas of 200 and 205 m2 g−1, respectively, and conductivities of 8.3 × 10−7 and 1.9 × 10−10 S cm−1, respectively. The latter material contained 77 wt% of silica. The original particulate nanostructure of the samples was preserved after carbonization. The carbon‐to‐nitrogen atomic ratio was 7.2 and 7.9; the nitrogen content in the carbonized polyaniline–poly(N‐vinylpyrrolidone) particles was 10.8 wt%. Thermogravimetric analysis in air revealed their stability to be up to 500 °C. This is comparable with commercial multi‐wall carbon nanotubes, which have similar areas of application. The nitrogen‐containing carbons are potentially useful as supports for catalysts and in applications where carbon of higher hydrophilicity would be of benefit. Copyright © 2010 Society of Chemical Industry
Synthesis and UV curing kinetics of rapidly UV‐curable hyperbranched polycarbosiloxanes
Authors: Wang Sheng‐Jie , Liu Xin , Kong Jie , Tian Wei , Fan Xiao‐Dong , Xu Hai , Lu Jian‐Ren
Published: May 2010

Hyperbranched polycarbosiloxanes with peripheral photo‐crosslinkable groups were synthesized through controllable hydrosilylation reaction from A2‐type and CB3‐type monomers. The polymerization of the monomer pairs was monitored using Fourier transform infrared spectroscopy, from which it was found that vinyl silane and methacrylate groups reacted with hydride silane from the beginning of the reaction. The results thus suggest a step‐by‐step polymerization rather than a two‐step process for this system. The polycarbosiloxanes could be cured rapidly in either nitrogen or air atmosphere, this feature making them attractive for potential application as precursors of advanced ceramic devices with complex structures. The effects of light intensity, reaction temperature and atmosphere on the UV curing rate (Rp) and conversion (α) of the photo‐crosslinkable groups were characterized carefully, and the curing kinetics was also investigated systematically. The results show that Rp and α increased with an increase of light intensity or temperature, and that the inhibiting effect of oxygen in air could be suppressed by enhancing the irradiation intensity. Copyright © 2010 Society of Chemical Industry
Synthesis of thermosensitive guar‐based hydrogels with tunable physico‐chemical properties by click chemistry
Authors: Tizzotti Morgan , Labeau Marie‐Pierre , Hamaide Thierry , Drockenmuller Eric , Charlot Aurélia , Fleury Etienne
Published: May 2010

Thermosensitive guar‐based hydrogels are obtained in water solutions by copper‐catalyzed 1,3‐dipolar cycloaddition between alkyne‐functionalized guars and α,ω‐diazido‐poly[(ethylene glycol)‐co‐(propylene glycol)]. Characterization by TGA, HR‐MAS 1H NMR, and rheology have shown that hydrogels with tunable physico‐chemical properties, such as crosslinking density, viscoelasticity, swelling ratio, and so forth, could be obtained by varying the guar molar mass, the degree of alkyne functionality, the guar/crosslinker weight ratio, and the reaction temperature. Based on swelling measurements, it has been shown that the thermal sensitiveness of guar‐based hydrogels is fast, reversible, and intimately related to the weight fraction of the thermosensitive crosslinker in the network. Finally, the monitoring of doxorubicin hydrochloride release has demonstrated the potential of these hydrogels as temperature‐dependent drug release devices. The robust, efficient, and orthogonal approach described herein represents a general approach towards the development of well‐controlled guar‐based hydrogels using α,ω‐diazido crosslinkers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2733–2742, 2010
Fluorescent and electrochromic aromatic polyamides with 4‐tert‐butyltriphenylamine chromophore
Authors: Hsiao Sheng‐Huei , Liou Guey‐Sheng , Kung Yi‐Chun , Chang Yu‐Ming
Published: May 2010

A new triphenylamine‐based aromatic dicarboxylic acid monomer, 4‐tert‐butyl‐4′,4″‐dicarboxytriphenylamine (2), was synthesized from the cesium fluoride mediated N,N‐diarylation reaction of 4‐tert‐butylaniline with 4‐fluorobenzonitrile and subsequent alkaline hydrolysis of the dinitrile intermediate. A series of six aromatic polyamides 4a‐4f with tert‐butyltriphenylamine groups was prepared from the newly synthesized dicarboxylic acid and various aromatic diamines. These polyamides were readily soluble in many organic solvents and could be solution‐cast into flexible and strong films. The glass‐transition temperatures of these polymers were in the range of 274–311 °C. These polymers exhibited strong UV‐vis absorption bands at 356–366 nm in NMP solution. Their photoluminescence spectra showed maximum bands around 433–466 nm in the blue region. Cyclic voltammograms of all the polyamides exhibited reversible oxidation redox couples in acetonitrile. The polyamide 4f, with tert‐butyltriphenylamine segment in both diacid and diamine residues, exhibited stable electrochromic characteristics with a color change from a colorless neutral form, through a green semioxidized form, to a deep purple fully oxidized form. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2798–2809, 2010
X‐ray computed tomography‐based modeling of polymeric foams: The effect of finite element model size on the large strain response
Authors: Wismans J. G. F. , Govaert L. E. , van Dommelen J. A. W.
Published: May 2010

A hybrid numerical–experimental approach is used to characterize the macroscopic mechanical behavior of polymeric foams. The method is based on microstructural characterization of foams with X‐ray computed tomography (CT) and conversion of the data to finite element (FE) models. The 2D models are created from a 3D close‐celled foam and subjected to compression loads. Since the large strain regime is explored, contact between elements is incorporated. It is shown that, for calculating the effective Young's modulus, a model consisting of at least 112–122 cells in the model should be used, whereas for the large strain regime 122–142 cells in the model are needed. Discretization had a significant influence on the results, where relatively coarse elements caused loss of connectivity in the cell walls and thickening of the cell walls. It is shown that at least three to four elements should be taken over the thickness of the cell walls for these structures. Finally, a good qualitative agreement is observed between the deformations found with the FE models and in situ compression experiments of an open‐celled foam during X‐ray CT. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1473–1482, 2010
Religious coping strategies in patients diagnosed with breast cancer in the UK
Authors: Thuné‐Boyle I. C. V. , Stygall J. , Keshtgar M. R. S. , Davidson T. I. , Newman S. P.
Published: May 2010

Objectives: The use of religious/spiritual coping strategies may be particularly prevalent when dealing with the stress of a cancer diagnosis. There has, however, been very little research conducted on this topic outside the USA. Existing measures of coping largely ignore the complexity of religious/spiritual coping and its potential to be adaptive as well as maladaptive. The aim of this study was to examine the prevalence of various religious coping strategies in a UK cancer sample.

Method: A longitudinal design assessed religious coping strategies in patients newly diagnosed with breast cancer at the time of surgery and at 3 and 12 months post surgery. We recruited 202 patients of which, at 12 months, 160 remained. A non‐religious coping measure was included for comparison.

Results: The use of religious coping strategies was overall common; up to 73% of patients used positive religious coping to some degree at surgery and up to 53% experienced various religious/spiritual struggles. The use of some religious coping strategies showed differing patterns of change across time while others remained stable.

Conclusion: Using religious/spiritual resources in the coping process during the early stages of breast cancer appears common in the UK. Patients may benefit from having their spiritual needs addressed as experiencing some form of religious/spiritual struggle may serve as a barrier to illness adjustment. Health‐care professionals should also be aware that some religious coping strategies may be more prevalent at different times during the first year of illness. Copyright © 2010 John Wiley & Sons, Ltd.
The influence of the group V/III molar precursor ratio on the structural properties of InGaN layers grown by HPCVD
Authors: Durkaya G. , Buegler M. , Atalay R. , Senevirathna I. , Alevli M. , Hitzemann O. , Kaiser M. , Kirste R. , Hoffmann A. , Dietz N.
Published: May 2010

The influence of the group V/III molar precursor ratio on the surface morphological and electrical properties of In0.65Ga0.35N epilayers has been investigated. The layers studied have been grown by high‐pressure chemical vapor deposition, a growth technique that utilizes the reactor pressure as an additional processing parameter. The surface morphology analysis revealed that with the increasing V/III molar precursor ratio, the surface morphology degrades with increasing surface roughness and decreasing average grain areas. The free carrier concentration in the In0.65Ga0.35N epilayers increased with the increased group V/III molar precursor ratios in the 700–3000 range.
Structural properties of semipolar AlxGa1−xN($1\bar {1}03$) films grown on ZnO substrates using room temperature epitaxial buffer layers
Authors: Ueno Kohei , Kobayashi Atsushi , Ohta Jitsuo , Fujioka Hiroshi
Published: May 2010

$1\bar {1}03$We have grown AlxGa1−xN films on semipolar ZnO ($1\bar {1}03$) substrates by pulsed laser deposition (PLD). The direct growth of Al0.25Ga0.75N on ZnO ($1\bar {1}03$) substrates at 850 °C results in the formation of c‐axis oriented materials with poor crystallinity due to serious interfacial reactions that occur between Al0.25Ga0.75N and ZnO. However, epitaxial AlxGa1−xN ($1\bar {1}03$) films can be grown on ZnO substrates by the incorporation of PLD room temperature (RT) epitaxial buffer layers. From X‐ray symmetric reciprocal space mapping studies, the [$1\bar {1}03$] directions of all AlxGa1−xN ($1\bar {1}03$) layers are slightly tilted toward the c‐axis from that of the ZnO substrate. We also found that the magnitude of the crystallographic tilt of AlxGa1−xN ($1\bar {1}03$) increases with AlN mole fraction x. This tendency can be explained by a reduction in the average misfit dislocation interval due to the increasing lattice mismatch between AlxGa1−xN and ZnO with AlN mole fraction x.
Design and performance of LEDs with circular geometry
Authors: Wang X.H. , Lai P.T. , Choi H.W.
Published: May 2010

InGaN light‐emitting diodes (LEDs) on sapphire substrate in the shape of cuboid and circular disk are diced via ultraviolet nanosecond laser micromachining. The geometrical influence on light extraction and emission pattern are evaluated. Our postulation on the optical characteristics of circular LEDs is qualitatively confirmed according to ray‐tracing simulation. The enhancement in light extraction over conventional cuboid chips is more than 10% according to measurements of our fabricated devices. The fair consistency between the simulation result and measurements indicates that the circular design is indeed effective for improving light extraction from InGaN LEDs. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)