bluuebunny/crossref_metadata_2025 huggingface dataset:
A locally conformal FDTD analysis of a thin printed antenna for wideband wireless applications
Authors: Cappelletti G. , Caratelli D. , Cicchetti R.
Published: June 2010

A compact wideband planar‐printed antenna for wireless communications is presented. A suitable shape of the antenna arms and a proper tapering of the feeding line are employed to achieve an impedance bandwidth of more than 10 GHz useful to meet the requirements of several wireless communication standards. An enhanced locally conformal finite‐difference time‐domain (FDTD) numerical procedure, based on a suitable normalization of the electromagnetic field‐related quantities together with a near‐to‐far‐field transformation, is developed to perform the full‐wave analysis of the radiating structure. The proposed numerical procedure allows the accurate evaluation of the electromagnetic field distribution from the FDTD domain up to the far‐field region, achieving a reduced computational burden compared with conventional FDTD formulations. Using the proposed technique, the electromagnetic and circuital behaviour of the antenna is then derived and analyzed in detail. Numerical results concerning the antenna parameters are in good agreement with experimental measurements. Copyright © 2010 John Wiley & Sons, Ltd.
Organizational identification: Extending our understanding of social identities through social networks
Authors: Jones Candace , Volpe Elizabeth Hamilton
Published: June 2010

Although organizational identification is founded on social identity and symbolic interactionist theories, current theories emphasize a social identity whereby organizational members categorize themselves and others based on roles and membership in an organization or work unit. In contrast symbolic interactionism, which resides in interpersonal relationships, is rarely theorized or empirically assessed in studies of organizational identification. We use survey data collected at an academic institution to explore how the strength and structure of an individual's social network both directly influences organizational identification as well as moderates the relation between social identity, or categorical, antecedents and organizational identification. Our results show that the size of an individual's network as well as the interaction between relationship strength and prestige better explain organizational identification than do antecedents based solely on categorization and social comparison processes. Thus networks of relationships, which have been a foundational but much neglected premise and process for organizational identification, are brought back into a theory of organizational identification. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and evaluation of silica hydride‐based fluorinated stationary phases
Authors: Pesek Joseph J. , Matyska Maria T. , Prajapati Kavita V.
Published: June 2010

Two novel silica hydride‐based fluorinated bonded phases have been synthesized using a hydrosilation procedure to test combined fluorine and hydride selectivity. The bonded moieties were characterized by elemental and spectral analysis. Chromatographic testing was done using hydrophilic analytes in the aqueous normal phase mode. At higher amounts of the nonpolar solvent in the mobile phase, there should be increased retention for solutes such as acids, bases and other polar compounds, whereas nonpolar solutes can be retained when water is increased as in RP chromatography. The synergistic effects of the fluorinated phase selectivity and aqueous normal phase retention on a hydride surface have been explored for small polar molecules. The stability and repeatability of the hydride‐based fluorinated stationary phases were evaluated. The use of acetone as the organic component in the mobile phase was also tested.
Improvement of hepatorenal syndrome with extracorporeal albumin dialysis mars: Results of a prospective, randomized, controlled clinical trial
Authors: Mitzner Steffen R. , Stange Jan , Klammt Sebastian , Risler Teut , Erley Christiane M. , Bader Brigitte D. , Berger Elke D. , Lauchart Werner , Peszynski Piotr , Freytag Jens , Hickstein Heiko , Loock Jan , Löhr Johannes-Mathias , Liebe Stefan , Emmrich Jörg , Korten Gero , Schmidt Reinhard
Published: June 2010

In hepatorenal syndrome (HRS), renal insufficiency is often progressive, and the prognosis is extremely poor under standard medical therapy. The molecular adsorbent recirculating system (MARS) is a modified dialysis method using an albumin-containing dialysate that is recirculated and perfused online through charcoal and anion-exchanger columns. MARS enables the selective removal of albumin-bound substances. A prospective controlled trial was performed to determine the effect of MARS treatment on 30-day survival in patients with type I HRS at high risk (bilirubin level, ≥15 mg/dL) compared with standard treatment. Thirteen patients with cirrhosis with type I HRS were included from 1997 to 1999. All were Child’s class C, with Child-Turcotte-Pugh scores of 12.4 ± 1.0, United Network for Organ Sharing status 2A, and total bilirubin values of 25.7 ± 14.0 mg/dL. Eight patients were treated with the MARS method in addition to hemodiafiltration (HDF) and standard medical therapy, and 5 patients were in the control group (HDF and standard medical treatment alone). None of these patients underwent liver transplantation or received a transjugular intrahepatic portosystemic shunt or vasopressin analogues during the observation period. In the MARS group, 5.2 ± 3.6 treatments (range, 1 to 10 treatments) were performed for 6 to 8 hours daily per patient. A significant decrease in bilirubin and creatinine levels (P< .01) and increase in serum sodium level and prothrombin activity (P< .01) were observed in the MARS group. Mortality rates were 100% in the control group at day 7 and 62.5% in the MARS group at day 7 and 75% at day 30, respectively (P< .01). We conclude that the removal of albumin-bound substances with the MARS method can contribute to the treatment of type I HRS.
Playing (and replaying) the waiting game
Authors: Vanness David J.
Published: June 2010

A shortage of donor liver grafts unfortunately results in approximately 10% of patients dying whilst listed for a liver transplant in Europe and the United States. Thus it is imperative that all available organs are used as efficiently as possible. This paper reports upon the application of a simulation modelling approach to assess the impact of several alternative allocation policies upon the cost effectiveness of this technology at one liver transplant centre in the UK. The impact of changes in allocation criteria on the estimated net life expectancy, average net costs and overall cost effectiveness of the transplantation programme were evaluated. The incremental cost effectiveness ratio (ICER) for the base case allocation policy, based upon the time spent on the waiting list (i.e., longest wait first) was 11,557 pounds sterling at 1999 prices. The ICERs associated with an allocation policy based upon age (lowest age first), and an allocation policy based upon the severity of the pre-transplant condition of the patient (with most severely ill patients given a lower priority) were lower than the base case at 10,424 pounds sterling and 9,077 pounds sterling, respectively. The results of this modelling study suggest that the overall cost effectiveness of the liver transplantation programme could be improved if the current allocation policy were modified to give more weight to the age of the patient and the reduced chances of success of the most severely ill patients.
Adult living donor transplants-which portion of the liver to use?
Authors: Humar Abhi
Published: June 2010

Abstract

Hypothesis:

Few studies have investigated the results of research focused on living donor adult liver transplantation. Different characteristics between right- and left-lobe grafts have not yet been clarified in living-donor adult liver transplantation. Left-lobe grafts remain an important option, even in adult recipients.

Setting:

A single liver transplant center with a long history of hepatic resection.

Patients:

Forty-five donors received left-lobe (n = 39) and right-lobe (n = 6) grafts. The clinicopathologic data for the donor, graft, and recipient were compared. All left-lobe grafts were extended grafts that included the middle hepatic vein, and 24 of the 39 left-lobe grafts included the left caudate lobe. No right-lobe graft included a middle hepatic vein.

Results:

The postoperative aspartate aminotransferase and total bilirubin values of the donor in the right-lobe graft group were higher, and the postoperative hospital stay was longer than in the left-lobe graft group. Graft weight in the left-lobe graft group was lighter than in the right-lobe graft group (median weight, 450 vs 675 g). The median graft weight divided by the standard liver volume in the left-lobe graft group was 41% (range, 21%-66%), compared with 52% (range, 47%-75%) in the right-lobe graft group. We found no difference in terms of the incidence of postoperative complications between groups. No difference in induced complications of small-for-size grafts such as intractable ascites and persistent hyperbilirubinemia was evident between groups. The survival rate for grafts at 18 months was 75.0% in the right-lobe graft group compared with 85.6% in the left-lobe group. In the right-lobe graft group, we found a few cases in which a marked poor-perfusion area in the anterior segment caused liver dysfunction.

Conclusions:

Left-lobe grafts are a feasible option for living-donor adult liver transplantation, and in the case of right-lobe grafts, hepatic venous drainage is one of the most critical problems.
Treatment of renal dysfunction after orthotopic liver transplantation: Options and outcomes
Authors: Gonwa Thomas A.
Published: June 2010

Chronic nephrotoxicity is one of the most serious side-effects of calcineurin inhibitor treatment and a factor in mortality and morbidity after liver transplantation. In our transplant centre, among patients who underwent a liver transplantation between January 1989 and December 2000, 14 liver graft recipients (6.86%) developed de novo severe renal dysfunction as defined by a serum creatinine concentration above 200 micromol/L. Renal biopsy was performed in nine cases and evidenced histological lesions compatible with chronic nephrotoxicity related to calcineurin inhibitor treatment. For nine patients, we report the results of a prospective non-randomized study consisting of cyclosporine or tacrolimus withdrawal associated with administration of mycophenolate mofetil or azathioprine. Despite this therapeutic modification, we did not observe a significant renal function improvement but on the other hand, there was no graft rejection. (Clin Transplant 2002;16:368-373.)
Hepatorenal syndrome, hepatopulmonary syndrome, and now, hepatospinal syndrome?
Authors: Bain Vincent G.
Published: June 2010

Abstract

Background & Aims:

Hepatic myelopathy is a rare complication of chronic liver disease, causing progressive spastic paraparesis. Today, no therapy of this disorder has been established. Commonly used therapeutic strategies for hepatic encephalopathy aiming at the reduction of plasma ammonia levels such as protein restriction, oral neomycin, lactulose, or ornithine aspartate fail to improve the symptoms of hepatic myelopathy. The aim of this study was to find out whether orthotopic liver transplantation (OLT) may improve hepatic myelopathy.

Methods:

Follow-up examinations of 3 patients with severe hepatic myelopathy before and after OLT.

Results:

In all 3 patients, the neurologic status improved significantly after liver transplantation. The grade of improvement was related to the time interval between onset of the first symptoms of hepatic myelopathy and liver transplantation.

Conclusions:

Early recognition of hepatic myelopathy is important because timely liver transplantation as an established therapy for end-stage liver disease offers the chance of complete recovery from hepatic paraparesis. (Gastroenterology 2003;124:346-351.)
Vancomycin-resistant enterococcal infections: Cause for concern?
Authors: Snydman David R.
Published: June 2010

Abstract

Objectives:

To determine the economic and clinical outcomes associated with infection with vancomycin-resistant Enterococcus (VRE) and to compare these outcomes to those associated with infection with vancomycin-sensitive Enterococcus (VSE).

Methods:

During a 3-month, prospective, cohort study of 117 high-risk, critically ill patients we collected complete clinical and demographic and ICU cost data from all patients during their ICU stays.

Results:

After adjusting for variables in a stepwise multiple regression model VRE infections were associated with a median attributable increased ICU cost per patient of $33,251 (38,088 euros) and an increased length of hospital stay (LOS) of 22 days, while VSE infections were associated with an increased cost of $21,914 (25,102 euros) and an increased LOS of 27 days. The effect of VRE and VSE infections were not significantly different. Over the entire cohort the attributable cost per ICU patient day associated with VRE infection was $304 (348 euros).

Conclusions:

The attributable cost of ICU care associated with VRE infection is $33,251 (38,088 euros) and per ICU patient day was $304 (348 euros). VRE and VSE infections do not differ in associated cost of ICU care, LOS, or mortality. Any VRE control strategy is cost-effective if the overall cost per ICU patient-day is less than $304 (348 euros).
Protein Adsorption on a Glycosylated Polyacrylonitrile Surface: Monitoring with QCM and SPR
Authors: Che Ai‐Fu , Huang Xiao‐Jun , Xu Zhi‐Kang
Published: June 2010

A simple and efficient method to fabricate a glycosylated surface on a polyacrylonitrile‐based film is described. Construction and protein adsorption processes were monitored in situ using a QCM. A PANCHEMA film was deposited on the gold surface of the quartz crystal, and the glycosylated surface was then constructed through surface modification. Con A and BSA were used as probes to study the specificity of this surface to proteins. It can recognize Con A, while showing no specific interaction with BSA. The binding affinity indicates the presence of strong multivalent interactions between Con A and the glucose residues (cluster glycoside effect). Reproducibility and repeatability of the glycosylated polymer surface are sufficient to allow specific adsorption of Con A.

magnified image
Polycation Structure Mediates Expression of Lyophilized Polycation/pDNA Complexes
Authors: Hahn Lewis D. , Kong Hyunjoon , Mooney David J.
Published: June 2010

Lyophilization of polycation/pDNA complexes provides stable, long‐term storage of complexes prior to clinical use but also reduces gene delivery efficiency. We examined whether polycation structure mediates effects of lyophilization on gene expression. Linear and branched PEI of the same molecular weight were used as a model system. Interestingly, pDNA/linear PEI complexes led to much smaller effects on gene expression following lyophilization compared with branched PEI complexes. The effect of polycation structure correlated with changes in dissociation ability of pDNA/PEI complexes. These results will be useful for developing new gene delivery vehicles.

magnified image
Poly(β‐cyclodextrin)/Curcumin Self‐Assembly: A Novel Approach to Improve Curcumin Delivery and its Therapeutic Efficacy in Prostate Cancer Cells
Authors: Yallapu Murali Mohan , Jaggi Meena , Chauhan Subhash C.
Published: June 2010

A novel PCD/CUR self‐assembly approach for improved curcumin delivery to prostate cancer cells is described. The formation of PCD/CUR was confirmed using FTIR, DSC, TGA, and SEM/TEM, and their stability and solubility under physiological conditions was demonstrated. A mechanism for self‐assembly is proposed. Intracellular uptake of the self‐assemblies was studied by flow cytometry and immunofluorescence microscopy. The therapeutic efficacy was determined by cell proliferation and colony formation assays using C4‐2, DU145 and PC3 prostate cancer cells. The results suggest that the PCD/CUR formulation could be a useful system for improving curcumin delivery and its therapeutic efficacy in prostate cancer.

magnified image
Synthesis and Characterization of Highly Luminescent Copolymers of Methyl Methacrylate and Eu‐Complexed 5‐Acryloxyethoxymethyl‐8‐hydroxyquinoline
Authors: Xu Cun‐Jin , Li Bo‐Geng
Published: June 2010

Highly luminescent Eu‐containing copolymers were synthesized through the copolymerization of Eu‐complex monomer featuring TTA and 5‐acryloxyethoxymethyl‐8‐hydroxyquinoline with MMA, and characterized by FT‐IR, UV–Vis, GPC, TGA, and DSC. The results indicated that the copolymers have not only a good solubility, thermal stability, and high glass transition temperatures, but also an intense red emission at 612 nm, corresponding to the 5D0 → 7F2 transition of Eu(III) ions under UV excitation. Compared with the Eu‐complex monomer, the Eu‐copolymers exhibited much higher luminescence lifetimes and efficiencies. Moreover, the luminescence intensities of the copolymers were much higher than those of the Eu‐complex/poly(methyl methacrylate) blend system at the same Eu content, and increased nearly linearly with an increase in the Eu content within 5.33 wt.‐%, and no significant concentration quenching phenomenon was observed at the Eu content up to 10.72 wt.‐%. In the blend system, however, the linear relationship between the luminescence intensity and Eu content was observed within 3.30 wt.‐%, and then the blend system showed typical emission concentration quenching on further increase in the Eu content. The improvement of the luminescence properties for the copolymers may be attributed to the special microenvironment, in which the Eu‐complex units are uniformly bonded to and surrounded by the polymer chain. These excellent photoluminescence properties may enable the novel copolymers to be used as pure red‐emitting materials.

magnified image
Synthesis and Evaluation of Water‐Soluble Fluorinated Dendritic Block‐Copolymer Nanoparticles as a 19F‐MRI Contrast Agent
Authors: Ogawa Michihiro , Nitahara Satoshi , Aoki Hiroyuki , Ito Shinzaburo , Narazaki Michiko , Matsuda Tetsuya
Published: June 2010

Well‐defined water‐soluble fluorinated polymer nanoparticles (PNPs) with a high fluorine content and biocompatibility were successfully prepared by living radical polymerization (LRP) of 2,2,3,3‐tetrafluoropropyl methacrylate (TFPMA) from the polyamidoamine dendrimer macroinitiator (PAMAM‐Br), and successive block polymerization of carboxybetaine monomer (CMB). The obtained core–shell type PNPs (PAMAM‐g‐PTFPMA‐b‐PCMB) showed high solubility in water and a sphere‐like structure with a diameter in the range of 15–80 nm in water. The short 19F‐NMR spin–lattice relaxation time (T1) (<250 ms) of PAMAM‐g‐PTFPMA‐b‐PCMB allowed the use of fast repetition time. The spin–spin relaxation time (T2) was evaluated to be as low as 10 ms. 19F‐MRI in vitro signals can be detectable even at concentrations lower than 1 µM (particle concentration). These results demonstrate that a new type of 19F‐MRI contrast agent can be developed by the molecular design using the dendrimer‐initiated LRP method.

magnified image
Lifetime Assessment of Load‐Bearing Polymer Glasses: An Analytical Framework for Ductile Failure
Authors: Visser Hendrikus A. , Bor Ton C. , Wolters Mannes , Engels Tom A. P. , Govaert Leon E.
Published: June 2010

The most widespread application of polymers in structural applications is their use as pipe material for e.g., gas distribution systems. Pipes have a design lifetime of typically 50 years, which rules out real‐time lifetime assessment methods. Here, an engineering approach is presented, which makes it possible to predict long‐term ductile failure of loaded glassy polymers based on short‐term tests. The approach is based upon the hypothesis that failure is governed by accumulation of plastic deformation up to a critical strain. A pressure‐modified Eyring relation is employed to calculate the accumulation of plastic strain for any simple loading geometry. It is demonstrated that the approach can produce accurate quantitative time‐to‐failure predictions for loaded PC specimens and uPVC pipe segments.

magnified image
Structural, Electrical, Mechanical, and Thermal Properties of Electrospun Poly(lactic acid)/Polyaniline Blend Fibers
Authors: Picciani Paulo H. S. , Medeiros Eliton S. , Pan Zhongli , Wood Delilah F. , Orts William J. , Mattoso Luiz H. C. , Soares Bluma G.
Published: June 2010

Conducting electrospun fiber mats based on PLA and PAni blends were obtained with average diameter values between 87 and 1 006 nm with PAni quantities from 0 to 5.6 wt.‐%. Structural characteristics of fiber mats were compared to cast films with the same amount of PAni and studied by SEM, SAXS, and AFM. Thermal properties of fiber mats and cast films were compared by DSC analyses. Mechanical properties of fiber mats were also evaluated. It was found that electrospinning process governs the crystal structure of the fibers and strongly affects fiber properties. New properties of PLA/PAni blends are reported due to the size fiber reduction.

magnified image
Design and Evaluation of Peptide Amphiphiles with Different Hydrophobic Blocks for Simultaneous Delivery of Drugs and Genes
Authors: Wiradharma Nikken , Tong Yen Wah , Yang Yi‐Yan
Published: June 2010

In this study, peptides with six different compositions were designed and synthesized to study the effect of the structure of the hydrophobic block in triblock oligopeptide amphiphiles ((AmX)nH5K15) on self‐assembly properties, drug loading capacity and gene expression efficiency. The peptides were synthesized using a standard Fmoc‐solid phase peptide synthesis protocol, which are A12H5K15, A11FH5K15, (A5F)2H5K15, (A3F)3H5K15, (AF)6H5K15 and (AL)6H5K15. A12H5K15, A11FH5K15, (A5F)2H5K15 and (A3F)3H5K15, formed micelles at concentrations above 200 mg · L−1 with large size or aggregation. However, (AF)6H5K15 and (AL)6H5K15 had CMC values of 42 and 49 mg · L−1 respectively, and the resulting micelles were much smaller in size as compared to the other peptide designs (108 and 233 nm for (AF)6H5K15 and (AL)6H5K15, respectively). In addition, both peptides were able to load paclitaxel (PTX) into nanoparticles although PTX‐loaded (AF)6H5K15 nanoparticles had a smaller size (278 versus 295 nm, respectively). Encapsulation efficiency of PTX with (AF)6H5K15 nanoparticles was 74%. Gene transfection studies showed that luciferase expression level induced by (AF)6H5K15 micelles in HepG2 cell line was much higher than that mediated by (AL)6H5K15 micelles at their respective optimal N/P ratios (3.2 × 108 versus 3.9 × 107 RLU · mg proteins−1). Therefore, simultaneous delivery of PTX and luciferase‐encoding plasmid was conducted using (AF)6H5K15 micelles against HepG2 cells, and the results demonstrated that the co‐delivery of PTX at 0.01 mg · L−1 further increased luciferase expression level from 3.2 × 108 to 8.0 × 108 RLU · mg proteins−1 at the optimal N/P ratio (i.e., 18). In summary, it is important to optimize the hydrophobic block of the oligopeptide amphiphiles in order to achieve desired properties for co‐delivery of drugs and genes.

magnified image
Microscopic Fourier Transform Infrared Characterization on Two Types of Spherulite with Polymorphic Crystals in Poly(heptamethylene terephthalate)
Authors: Yen Kai Cheng , Woo Eamor M. , Tashiro Kohji
Published: June 2010

FTIR microspectrometry with in situ temperature variation and IR‐peak‐mapping capability, and POM characterization were used to study the crystal distribution in dual spherulites in poly(heptamethylene terephthalate). By tracing the crystalline IR bands of the α‐crystal and β‐crystal to get the crystal distribution, the techniques resolve that the ringed and ringless spherulites comprise α‐ and β‐crystals, respectively. In addition, temperature‐dependent IR analyses on the spots related to the two crystals also reveal the α‐ and β‐crystals melt at 98 and 104 °C, respectively. The ringed and ringless spherulites were proven to be correlated with the α‐ and β‐crystal forms, respectively.

magnified image
Photodissociation Rate Constants of New Light Sensitive Alkoxyamines
Authors: Versace Davy‐Louis , Lalevée Jacques , Fouassier Jean‐Pierre , Guillaneuf Yohann , Bertin Denis , Gigmes Didier
Published: June 2010

The photochemical properties of two new photocleavable alkoxyamines bearing a benzophenone‐derived chromophore were studied by electron spin resonance (ESR). The CO bond cleavage has been demonstrated and the photolysis rate constants (kd) determined over a large range of light intensity through the monitoring of the nitroxide concentration in aerated conditions. The obtained kinetic data highlight for the first time the linear dependence of kd on the light intensity for alkoxyamines: this should be a driving factor for nitroxide mediated radical photopolymerization (NMP2).

magnified image
Hydrazine as a Nucleophile and Antioxidant for Fast Aminolysis of RAFT Polymers in Air
Authors: Shen Wenqing , Qiu Qian , Wang Yang , Miao Miao , Li Bingshu , Zhang Tianshu , Cao Aoneng , An Zesheng
Published: June 2010

The bifunctional role of hydrazine as a potent nucleophile and antioxidant was investigated for the rapid aminolysis of RAFT polymers within minutes in air with effective suppression of the formation of disulfides. Using both dithioesters and trithiocarbonates as model compounds, we showed that hydrazine exhibited a significantly improved aminolysis rate when compared with a commonly used primary alkyl amine. On the basis of the exellent results with CTAs, we further studied the aminolysis of RAFT polymers prepared with either dithioesters or trithiocarbonates. In accord with the aminolysis results on CTAs, hydrazine aminolyzed RAFT polymers in an impressively short time and, more importantly, it significantly suppressed the formation of disulfides as comfirmed with GPC.

magnified image
Synthesis of Amphiphilic Mushroom Cap‐shaped Colloidal Particles towards Fabrication of Anisotropic Colloidal Crystals
Authors: Xu Liang , Li Heng , Jiang Xi , Wang Jingxia , Li Lin , Song Yanlin , Jiang Lei
Published: June 2010

In this work, we design and synthesize a kind of amphiphilic mushroom cap‐shaped particles with wettability difference on the opposite sides of the particles. Colloidal crystals consisting of uniformly oriented anisotropic particles were fabricated on the water–air interface based on the wettability difference of particles. This simple approach offers a new way for self‐assembly of anisotropic colloidal crystal by amphiphilic design of particles.

magnified image
Nanotube Friendly Poly(N‐isopropylacrylamide)
Authors: Etika Krishna C. , Jochum Florian D. , Cox Michael A. , Schattling Philipp , Theato Patrick , Grunlan Jaime C.
Published: June 2010

Poly(N‐ispropylacrylamide) [PNIPAM] is a widely studied polymer for use in biological applications due to its lower critical solution temperature (LCST) being so close to the human body temperature. Unfortunately, attempts to combine carbon nanotubes (CNTs) with PNIPAM have been unsuccessful due to poor interactions between these two materials. In this work, a PNIPAM copolymer with 1 mol‐% pyrene side group [p‐PNIPAM] was used to produce a thermoresponsive polymer capable of stabilizing both single and multi‐walled carbon nanotubes (MWNTs) in water. The presence of pyrene in the polymer chain lowers the LCST less than 4 °C and the interaction with nanotubes does not show any influence on LCST. Moreover, p‐PNIPAM stabilized nanotubes show a temperature‐dependent dispersion in water that allows the level of nanotube exfoliation/bundling to be controlled. Cryo‐TEM images, turbidity, and viscosity of these suspensions were used to characterize these thermoresponsive changes. This ability to manipulate the dispersion state of CNTs in water with p‐PNIPAM will likely benefit many biological applications, such as drug delivery, optical sensors, and hydrogels.

magnified image
Synthesis and Chain‐Length Dependence of the Electronic Properties of π‐Conjugated Dithieno[3,2‐b:2′,3′‐d]pyrrole (DTP) Oligomers
Authors: Yassin Ali , Leriche Philippe , Roncali Jean
Published: June 2010

N‐(2‐ethylhexyl)dithieno[3,2‐b:2′,3′‐d]pyrrole has been prepared and its dimer and trimer have been synthesized by Stille coupling. The electrochemical and optical properties of these compounds have been investigated by cyclic voltammetry, UV–Vis, and fluorescence emission spectroscopies. The obtained results show that these strongly luminescent compounds can be oxidized into stable cation radical and dication state. The analysis of the chain length dependence of the electronic properties indicates that the predicted bandgap of an ideal polymer chain should be considerably smaller than the experimental results reported until now. This difference is discussed in terms of reactivity of the dithieno[3,2‐b:2′,3′‐d]pyrrole (DTP) unit.

magnified image
Prognostic implications of ezrin expression in human hepatocellular carcinoma
Authors: Kang Yun Kyung , Hong Seong Woo , Lee Hyucksang , Kim Woo Ho
Published: June 2010

Ezrin is known to regulate cellular survival, adhesion, migration, and invasion and has been identified as one of the key components of tumor progression and metastasis. The authors investigated ezrin expression in human hepatocellular carcinoma (HCC) and sought to determine its relation with clinicopathologic parameters, patients' outcome, and interacting molecular markers. Ezrin expression was assessed by immunohistochemical staining in 100 surgically resected HCCs using the tissue microarray method. A total of 28 HCCs showed high ezrin immunoreactivity, mainly in cytoplasm. Ezrin expression exhibited a positive correlation with c‐Met expression (P = 0.001), but showed no correlation with the expression of CD44s or E‐cadherin. HCCs expressing high level of ezrin were significantly associated with advanced TNM stage, poor Edmondson's histological grade, macroscopic portal vein invasion, tumor recurrence, and extrahepatic recurrence (P < 0.05). Univariate analysis showed that HCCs with high ezrin immunoreactivity were strongly associated with unfavorable overall and disease‐free survivals than HCCs with low or negative for ezrin immunoreactivity (P = 0.0001 and 0.0011, respectively). Furthermore, multivariate analysis demonstrated that a high level of ezrin expression was independently associated with poor overall survival (hazard ratio, 1.905; P = 0.011). The results suggest that ezrin expression could be a potential predictive marker of progression, metastasis, and prognosis in HCC. © 2010 Wiley‐Liss, Inc.
Synthesis, Characterization and Curing of Bioinspired Polymers Based on Vinyl Benzyl Thymine and Triethyl Ammonium Chloride
Authors: Barbarini Alejandro L. , Estenoz Diana A. , Martino Débora M.
Published: June 2010

A novel class of environmentally benign, non‐toxic and recyclable materials based on vinylbenzyl thymine (VBT) and an ionically‐charged vinylbenzyl triethylammonium chloride (VBA) monomers was studied. Several syntheses of VBT–VBA copolymers at various comonomer ratio and initiator concentrations were carried out at 65 °C using isopropanol as solvent. Samples were taken during the reactions to determine the monomer conversion, chemical composition and molecular weight distribution. The comonomers exhibited similar reactivities and random copolymers with similar chemical compositions were obtained. The curing process involved the irradiation of the copolymer films with a short‐wavelength UV light (254 nm) for different times, leading to film immobilization on the substrate. The light‐induced crosslinking reaction was followed by UV‐vis spectroscopy and the immobilization point relative to the gel point was determined. The kinetics of the crosslinking process pointed to a second‐order process with respect to the thymine concentration. The experimental results provide complementary information on photo‐induced immobilization of VBT–VBA films that are crucial for developing new classes of environmentally benign materials and new energy‐saving methods.

magnified image
Kinetics and Modeling of Batch and Semibatch Aqueous‐Phase NVP Free‐Radical Polymerization
Authors: Santanakrishnan Sandhya , Tang Lina , Hutchinson Robin A. , Stach Marek , Lacík Igor , Schrooten Jens , Hesse Pascal , Buback Michael
Published: June 2010

Aqueous‐phase free‐radical batch and semibatch polymerizations of NVP have been carried out with varying initial monomer and initiator concentrations. The rate of conversion was observed to increase as the initial monomer concentration was lowered, a result explained by the dependence of the propagation rate coefficient, kp, on monomer concentration. A kinetic model with termination and conversion‐dependent kp rate coefficients taken from independent studies provides a good description of the conversion profiles. A reasonable representation of polymer molecular‐weight averages and the complete MWD was obtained by assuming that the rate coefficient for transfer to monomer also varies as a function of monomer concentration and that a small amount of chain transfer to polymer occurs.

magnified image
Simulation of phase contrast MRI of turbulent flow
Authors: Petersson Sven , Dyverfeldt Petter , Gårdhagen Roland , Karlsson Matts , Ebbers Tino
Published: June 2010

Phase contrast MRI is a powerful tool for the assessment of blood flow. However, especially in the highly complex and turbulent flow that accompanies many cardiovascular diseases, phase contrast MRI may suffer from artifacts. Simulation of phase contrast MRI of turbulent flow could increase our understanding of phase contrast MRI artifacts in turbulent flows and facilitate the development of phase contrast MRI methods for the assessment of turbulent blood flow. We present a method for the simulation of phase contrast MRI measurements of turbulent flow. The method uses an Eulerian‐Lagrangian approach, in which spin particle trajectories are computed from time‐resolved large eddy simulations. The Bloch equations are solved for each spin for a frame of reference moving along the spins trajectory. The method was validated by comparison with phase contrast MRI measurements of velocity and intravoxel velocity standard deviation (IVSD) on a flow phantom consisting of a straight rigid pipe with a stenosis. Turbulence related artifacts, such as signal drop and ghosting, could be recognized in the measurements as well as in the simulations. The velocity and the IVSD obtained from the magnitude of the phase contrast MRI simulations agreed well with the measurements. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Correcting eddy current and motion effects by affine whole‐brain registrations: Evaluation of three‐dimensional distortions and comparison with slicewise correction
Authors: Mohammadi Siawoosh , Möller Harald E. , Kugel Harald , Müller Dirk K. , Deppe Michael
Published: June 2010

Eddy‐current (EC) and motion effects in diffusion‐tensor imaging (DTI) bias the estimation of quantitative diffusion indices, such as the fractional anisotropy. Both effects can be retrospectively corrected by registering the strongly distorted diffusion‐weighted images to less‐distorted T2‐weighted images acquired without diffusion weighting. Two different affine spatial transformations are usually employed for this correction: slicewise and whole‐brain transformations. However, a relation between estimated transformation parameters and EC distortions has not been established yet for the latter approach. In this study, a novel diffusion‐gradient‐direction–independent estimation of the EC field is proposed based solely on affine whole‐brain registration parameters. Using this model, it is demonstrated that a more distinct evaluation of the whole‐brain EC effects is possible if the through‐plane distortion was considered in addition to the well‐known in‐plane distortions. Moreover, a comparison of different whole‐brain registrations relative to a slicewise approach is performed, in terms of the relative tensor error. Our findings suggest that for appropriate intersubject comparison of DTI data, a whole‐brain registration containing nine affine parameters provides comparable performance (between 0 and 3%) to slicewise methods and can be performed in a fraction of the time. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Ultrashort echo time (UTE) MRI of the lung: Assessment of tissue density in the lung parenchyma
Authors: Togao Osamu , Tsuji Riki , Ohno Yoshiharu , Dimitrov Ivan , Takahashi Masaya
Published: June 2010

Nonuniform disruption of lung architecture is usually assessed by CT, which carries potential radiation risk. Here we report our use of a three‐dimensional ultrashort echo time MR method to image the lungs of normal mice at different positive end‐expiratory pressures in a 3‐T clinical MR system. The ultrashort echo time sequence in conjunction with a projection acquisition of the free induction decay could reduce the echo time to 100 μsec and provide a more inherent MR signal intensity from the lung parenchyma, which is usually invisible due to its short T*2 in conventional MRI methods. The signal intensity and T*2 was reduced as the positive end‐expiratory pressure became higher. Further, these parameters were highly correlated to the changes in lung volume (% lung expansion). The results indicated that the MR signal acquired at ultrashort echo time in the lung parenchyma represents interstitial tissue density including blood. The capability of acquiring sufficient MR signal would have implications for the direct assessment of parenchymal architecture in the lung. Therefore, ultrashort echo time imaging may have the potential to assist detection of early and localized pathological destruction of lung tissue architecture observed in various pulmonary disorders such as emphysema without incurring the risks of radiation exposure. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Maternal satisfaction with postpartum nursing centers
Authors: Hung Chich‐Hsiu , Yu Ching‐Yun , Liu Chin‐Fang , Stocker Joel
Published: June 2010

We explored predictors of women's satisfaction with postpartum nursing centers, which have become popular in Taiwan in recent years. After completing a consent form and demographic questionnaire, 401 women from different centers identified by proportional stratified quota sampling completed four questionnaires over the telephone after their fourth week postpartum. A high level of social support and low level of postpartum stress significantly predicted their satisfaction with the postpartum nursing centers. Future studies will be needed to determine whether, compared to traditional care at home, the postpartum nursing centers can help ease mothers' transition to parenthood and improve their childcare competence. © 2010 Wiley Periodicals, Inc. Res Nurs Health 33:345–354, 2010
Strengthening data quality in studies of migrants not fluent in host languages: A canadian example with reproductive health questionnaires
Authors: Strohschein Fay J. , Merry Lisa , Thomas Julia , Gagnon Anita J.
Published: June 2010

The need to collect health data from refugees and asylum seekers often requires that questionnaires be translated. Verifying the clarity, meaning, and acceptability of translated questionnaires with monolingual persons, individuals from the target population who primarily speak and understand only the test language, is one important step in the translation process. Reproductive health questionnaires were tested with persons monolingual in Hindi, Tamil, Urdu, Spanish, and French. Testing revealed problematic questions and how culture, education, and migration experience can affect perceptions of questions. Bilingual liaisons from the communities of interest facilitated recruitment of participants, but liaisons' vulnerable status and lack of familiarity with research posed challenges to the testing process. When conducting monolingual testing it is important to: carefully select liaisons (consider their gender, host‐language fluency, knowledge of research processes, and comfort with the subject matter of the research); recruit monolingual persons with characteristics representative of the research population; ensure adequate researcher involvement in all aspects of the testing process to triangulate data collection from various sources. © 2010 Wiley Periodicals, Inc. Res Nurs Health 33:369–379, 2010
Quality nursing care for hospitalized patients with advanced illness: Concept development
Authors: Izumi Shigeko , Baggs Judith G. , Knafl Kathleen A.
Published: June 2010

The quality of nursing care as perceived by hospitalized patients with advanced illness has not been examined. A concept of quality nursing care for this population was developed by integrating the literature on constructs defining quality nursing care with empirical findings from interviews of 16 patients with advanced illness. Quality nursing care was characterized as competence and personal caring supported by professionalism and delivered with an appropriate demeanor. Although the attributes of competence, caring, professionalism, and demeanor were identified as common components of quality care across various patient populations, the caring domain increased in importance when patients with advanced illness perceived themselves as vulnerable. Assessment of quality nursing care for patients with advanced illness needs to include measures of patient perceptions of vulnerability. © 2010 Wiley Periodicals, Inc. Res Nurs Health 33:299–315, 2010
Mehrgitterlöser für heterogene Materialien mit einem homogenisierungsbasierten Transfer für unstrukturierte Netze
Authors: Bayreuther C.G. , Miehe C.
Published: June 2010

Die Lösung großer Gleichungssysteme infolge der FE‐Diskretisierung heterogener Materialien mit Mehrgitterverfahren kann nur mittels geeigneter Transfer‐ und Grobgitteroperatoren effizient erfolgen. Wesentlicher Aspekt bei der Konstruktion der erforderlichen Operatoren ist die Verknüpfung mit einem diskreten Homogenisierungskonzept. Diese neue Strategie wird anhand eines repräsentativen Modellproblems mit bekannten alternativen Verfahren verglichen.
Coefficients of Runge‐Kutta Schemes for Itô Stochastic Differential Equations
Authors: Rössler Andreas
Published: June 2010

In order to approximate the solution of an Itô stochastic differential equation, embedded explicit stochastic Runge‐Kutta methods may be applied. Coefficients for such schemes are presented in this paper. Since embedded methods provide different orders of convergence, they may be applied for estimating the local error of the approximation process.
Morphological development in water assisted injection molded polyethylene/polyamide‐6 blends
Authors: Liu Shih‐Jung , Lin Wei‐Ru , Lin Kun‐Yeh
Published: June 2010

Water assisted injection molding (WAIM) has gradually become one of the most important polymer processing methods for making hollowed parts. This study examined the morphological development in water assisted injection molded high density polyethylene (HDPE)/polyamide‐6 (PA‐6) blends. Samples for microscopic observation were prepared by an 80‐ton injection‐molding machine equipped with a tube cavity and with a water injection unit. A distinct skin layer, core region, and channel layer were observed across the thickness. The shape and size of the dispersed phase depended on the position both across the part thickness and along the flow direction. Small and large particles coexisted in the skin and channel layers, indicating that both coalescence and disintegration of the dispersed phase occurred in these layers. High water pressures were found to mold parts with smaller polyamide particle distributions. Additionally, the morphology of water assisted injection molded parts was compared to that of gas assisted injection molded products. It was found that water molded parts exhibit a smaller polyamide particle distribution than their gas counterparts. Copyright © 2010 John Wiley & Sons, Ltd.
Environmental vapor induced self‐assembly of an amphiphilic block copolymer poly(styrene‐b‐acrylamide) onto the solid substrate
Authors: Yan Lifeng , Ji Jing , Xu Songsong , Bangal Prakriti R.
Published: June 2010

The chemical and micro‐structural changes at the top surface of the film of amphiphilic block copolymer poly(styrene‐b‐acrylamide) (PS950‐b‐PAM50) induced by different environmental conditions and temperature have been studied. Atomic force microscopy (AFM), Transmission electron microscopy (TEM), Scanning electron microscope (SEM), X‐ray Photoelectron Spectroscopy (XPS), and contact angle (CA) goniometry studies revealed that the roughness and the surface property in terms of hydrophilicity/hydrophobicity of the film strongly depend on the environmental conditions. Humidity, presence of solvent vapor and temperature at the time of film preparation have immense role in controlling surface properties. Hence, it is suggested that the surface properties of the amphiphilic block copolymer film can be tuned according to the requirement for its potential applications. Copyright © 2010 John Wiley & Sons, Ltd.
A biocompatible composite based on poly(ε‐caprolactone fumarate) and hydroxyapatite
Authors: Shafieyan Yousef , Sharifi Shahriar , Imani Mohammad , Shokrgozar Mohammad Ali , Aboudzadeh Neda , Atai Mohammad
Published: June 2010

Fabrication of biodegradable composites applicable as hard tissue substitutes consisting of poly(ε‐caprolactone fumarate) (PCLF), methacrylic acid (MAA), and hydroxyapatite (HA) was investigated. PCLF macromers were synthesized by reaction of PCL diol with fumaryl chloride in the presence of propylene oxide and characterized by gel permeation chromatography, FTIR, and 1H NMR spectroscopy. Composites were fabricated by incorporating HA as inorganic filler in PCLF matrix which followed by thermal curing of the composition using benzoyl peroxide and MAA as a free radical initiator and reactive diluent, respectively. Uniform distribution of the fine ceramic phase in the polymer matrix was elucidated by scanning electron microscopy. The effects of the initial macromer molecular weight and the filler volume fraction on mechanical properties and cytotoxicity of the composites were also examined. Significant enhancement in the mechanical properties was observed upon increasing HA content and/or initial PCLF molecular weight. The biocompatibility of the specimens was also improved with increasing ceramic phase. Copyright © 2010 John Wiley & Sons, Ltd.
Formation and Distribution of Silver Nanoparticles in a Functional Plasma Polymer Matrix and Related Ag+ Release Properties
Authors: Körner Enrico , Aguirre Myriam H. , Fortunato Giuseppino , Ritter Axel , Rühe Jürgen , Hegemann Dirk
Published: June 2010

Plasma polymer coatings with embedded Ag nanoparticles were deposited in a low pressure RF plasma reactor using an asymmetrical setup with an Ag electrode. The plasma polymer was deposited from a reactive gas/monomer mixture of CO2/C2H4 yielding a functional hydrocarbon matrix. In addition, Ar was simultaneously used to sputter Ag atoms from the Ag electrode, forming nanoparticles within the growing polymer matrix. The influence of the power input, gas ratio and coating thickness on both, the Ag content and the Ag nanoparticle morphology, as well as the distribution in the polymer matrix were investigated. It was found that both increasing the power input and the CO2 ratio result in a higher incorporation of Ag into the matrix.

magnified image
Super‐Hydrophobic Coatings Prepared by RF Magnetron Sputtering of PTFE
Authors: Drábik Martin , Polonskyi Oleksandr , Kylián Ondřej , Čechvala Juraj , Artemenko Anna , Gordeev Ivan , Choukourov Andrei , Slavínská Danka , Matolínová Iva , Biederman Hynek
Published: June 2010

Fluorocarbon plasma polymer films were prepared by RF magnetron sputtering in Argon from a balanced magnetron equipped with polytetrafluoroethylene (PTFE) target. Depending on the deposition conditions, primarily on the working gas pressure and distance between the target and the substrate, plasma polymer ﬁlms were obtained with distinctly different chemical composition and/or morphology, as measured by means of XPS, FTIR and AFM. These films possessed static contact angle of water values ranging from 112° to ≈170° i.e. their behaviour ranged from hydrophobic to superhydrophobic ones.

magnified image