bluuebunny/crossref_metadata_2025 huggingface dataset:
Speckle reduction imaging of breast ultrasound does not improve the diagnostic performance of morphology‐based CAD System
Authors: Tseng Hsin‐Shun , Wu Hwa‐Koon , Chen Shou‐Tung , Kuo Shou‐Jen , Huang Yu‐Len , Chen Dar‐Ren
Published: November 2011

Purpose.

Speckle reduction imaging (SRI) is a newly developed technique in ultrasound examination. This study aimed to compare the diagnostic performance of SRI and non‐SRI breast ultrasound examinations by using a morphology‐based computer‐aided diagnostic system.

Methods.

One hundred ten patients with pathologically proven breast lesions were enrolled consecutively from April 2008 to October 2008. SRI and non‐SRI ultrasound images were both obtained at the same examination for each patient. The regions of interest were manually sketched by an experienced physician without histological information. Nineteen practical morphologic features from the extracted contour were calculated and a support vector machine classifier identified the breast tumor as benign or malignant. Conventional binomial receiver operating characteristics curve analysis was used to represent the diagnostic performance of both SRI and non‐SRI.

Results.

Between SRI and non‐SRI methods, there were no significant differences in the area under the receiver operating characteristics curve (Az value: 0.82 versus 0.81), the sensitivity (78.9% versus 84.2%), and the specificity (73.6% versus 70.8%).

Conclusions.

Based on the morphology study, the performance of breast ultrasound in characterizing the solid breast mass as benign or malignant was not significantly improved with SRI. © 2011 Wiley Periodicals, Inc. J Clin Ultrasound, 2011;
Hospice eligibility in patients who died in a tertiary care center
Authors: Freund Katherine , Weckmann Michelle T. , Casarett David J. , Swanson Kristi , Brooks Mary Kay , Broderick Ann
Published: November 2011

BACKGROUND:

Hospice is a service that patients, families, and physicians find beneficial, yet a majority of patients die without receiving hospice care. Little is known about how many hospitalized patients are hospice eligible at the time of hospitalization.

METHODS:

Retrospective chart review was used to examine all adult deaths (n = 688) at a tertiary care center during 2009. Charts were selected for full review if the death was nontraumatic and the patient had a hospital admission within 12 months of the terminal admission. The charts were examined for hospice eligibility based on medical criteria, evidence of a hospice discussion, and hospice enrollment.

RESULTS:

Two hundred nine patients had an admission in the year preceding the terminal admission and a nontraumatic death. Sixty percent were hospice eligible during the penultimate admission. Hospice discussions were documented in 14% of the hospice‐eligible patients. Patients who were hospice eligible had more subspecialty consults on the penultimate admission compared to those not hospice eligible (P = 0.016), as well as more overall hospitalizations in the 12 months preceding their terminal admission (P = 0.0003), and fewer days between their penultimate admission and death (P = 0.001).

CONCLUSION:

The majority of terminally ill inpatients did not have a documented discussion of hospice with their care provider. Educating physicians to recognize the stepwise decline of most illnesses and hospice admission criteria will facilitate a more informed decision‐making process for patients and their families. A consistent commitment to offer hospice earlier than the terminal admission would increase access to community or home‐based care, potentially increasing quality of life. Journal of Hospital Medicine 2011;. © 2011 Society of Hospital Medicine.
A fast, simple, and reproducible automated synthesis of [18F]FPyKYNE‐c(RGDyK) for αvβ3 receptor positron emission tomography imaging
Authors: Valdivia Ana C. , Estrada Miriam , Hadizad Tayebeh , Stewart Duncan J. , Beanlands Rob S. , DaSilva Jean N.
Published: November 2011

[18 F]FPyKYNE‐c(RGDyK) was successfully synthesized by the Cu(I) catalyzed Huisgen 1,3‐dipolar cycloaddition of alkynes to azides using [18 F]FPyKYNE as a prosthetic group in an overall radiochemical yield of 12%–18% (decay‐corrected) and >99.5% chemical and radiochemical purities in 125 min including quality control. This simple, fully automated two‐step, two‐reactor approach consists of a quick and convenient purification of the prosthetic group using silica gel cartridges and its subsequent use for the labeling of the azido‐c(RGDyK) peptide via click chemistry.
Time‐resolved fluorescence microscopy of hematoporphyrin‐derivative in cells
Authors: Docchio F. , Ramponi R. , Sacchi C.A. , Bottiroli G. , Freitas I.
Published: November 2011

This work presents measurements of time‐resolved fluorescence microscopy of hematoporphyrin‐derivative (HpD) in single cells of mice tissue (both tumor and normal cells), in HeLa cells, and in solution. The measurements were performed using a pulsed‐laser microfluorometer with high spatial and temporal resolution. In agreement with the results obtained with other techniques, it has been found that the tumor cells examined present an HpD uptake about five times higher than that of the normal cells of the corresponding tissue and that, within a cell, HpD becomes localized mainly in the cytoplasm. It has also been found that the fluorescence decay time is different in cells as compared with solution, and that the presence of HpD stabilizes cell auto‐fluorescence. These results are discussed.
The plasma scalpel: A new thermal knife
Authors: Glover J. L. , Bendick P. J. , Link W. J. , Plunkett R. J.
Published: November 2011

A new thermal knife, the plasma scalpel, capable of simultaneous division of tissue and coagulation of blood vessels, is described. A high temperature argon gas plasma (unrelated to blood plasma) is created by passing the gas through a direct current arc, ionizing the gas and elevating its temperature to 3000°C. A small plasma cutting jet is formed by a nozzle at the tip of the handpiece. Liver resections and muscle transections performed in a canine model, and full thickness burn excisions in a pig skin model showed effective division of tissue and significantly less blood loss when compared to the steel scalpel. Wound healing studies of histologic comparisons and wound breaking strength were performed for steel, plasma, laser, and electrosurgical scalpel incisions in the skin of mice and rats. All thermal knife wounds showed localized tissue damage at the edges of the incision, but the events of healing began at the same time. Compared to the steel scalpel, there was a three to six day delay in the onset of healing, but healing occurred in the normal fashion and all thermal knife wounds reached the same healed breaking strength as the steel scalpel wounds. Clinically, the plasma scalpel has been used for 138 procedures in 96 patients. The majority of cases have been transection of muscle, hepatic resection or debridement, or soft tissue debridement. Muscle transection data for the plasma scalpel compared to the electrosurgical scalpel has shown virtually no blood loss with a shorter time to hemostasis for the plasma scalpel. The plasma scalpel has proved to be an effective thermal knife, capable of simultaneous division and coagulation. Further development work and proof of its efficacy in the clinical setting are necessary to establish the plasma scalpel and adequately demonstrate its proper role in surgery.
Synthesis of Polyester Nanoparticles in Miniemulsion Obtained by Radical Ring‐Opening of BMDO and Their Potential as Biodegradable Drug Carriers
Authors: Siebert Joerg Max , Baumann Daniela , Zeller Anke , Mailänder Volker , Landfester Katharina
Published: November 2011

5,6‐Benzo‐2‐methylene‐1,3‐dioxepane (BMDO) is used to obtain degradable polymeric nanoparticles via a statistical free‐radical copolymerization with MMA and styrene in direct miniemulsion. The nanoparticles are analyzed by means of IR, NMR, DLS, SEM, and TEM. They show excellent cellular uptake and drug delivery properties. The cellular uptake into HeLa cells of particles resulting from copolymerization of BMDO with styrene is drastically enhanced compared to pure polystyrene. As a model drug system, paclitaxel is incorporated in PBMDO particles and its release and the effect on HeLa cells is studied and compared to commercial drug formulations. It is found that a drug delivery system based on PBMDO shows an excellent pharmacological effect.

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Development of a Biodegradable, Temperature‐sensitive Dextran‐based Polymer as a Cell‐detaching Substrate
Authors: Sun Guoming , Kusuma Sravanti , Gerecht Sharon
Published: November 2011

A biodegradable, temperature‐sensitive dextran‐allyl isocyanate‐ethylamine (TSDAIE) as a nonenzymatic cell detachment polymeric substrate for human endothelial progenitor cells (EPCs) is developed and examined. The lower critical solution temperature of TSDAIE is determined; its phase transition occurrs at 18 to 22 °C. For EPC culture, cell culture flasks are coated with TSDAIE and type I collagen. The TSDAIE coating enables EPC detachment when the culture is cooled to 4 °C. The concentration of TSDAIE affects EPC attachment, which is thereby used to optimize the concentration of TSDAIE for coating. At the determined optimal concentration, TSDAIE is found to be compatible for use in EPC culture as revealed by cell attachment, spreading, proliferation, and phenotype. Overall, biodegradable TSDAIE shows promise for applications that culture and expand EPCs including vascular regenerative medicine and tissue engineering.

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Algebraic semantics for the (↔, ¬¬)‐fragment of IPC
Authors: Słomczyńska Katarzyna
Published: November 2011

We show that the variety of equivalential algebras with regularization gives the algebraic semantics for the (↔, ¬¬)‐fragment of intuitionistic propositional logic. We also prove that this fragment is hereditarily structurally complete.
JmjC‐domain containing histone demethylase 1B‐mediated p15Ink4b suppression promotes the proliferation of leukemic progenitor cells through modulation of cell cycle progression in acute myeloid leukemia
Authors: Nakamura Satoki , Tan Lin , Nagata Yasuyuki , Takemura Tomonari , Asahina Aya , Yokota Daisuke , Yagyu Tomohiro , Shibata Kiyoshi , Fujisawa Shinya , Ohnishi Kazunori
Published: November 2011

The histone demethylase JHDM1B has been implicated in cell cycle regulation and tumorigenesis. In addition, it has been reported that JHDM1B is highly expressed in various human tumors, including leukemias. However, it is not clearly understood how JHDM1B contributes to acute myeloid leukemia (AML) cell proliferation. In this study, we investigated the cellular and molecular function of JHDM1B in AML cells. In AML cell lines and AML‐derived ALDHhi (high aldehyde dehydrogenase activity)/CD34+ cells, the levels of JHDM1B mRNA were significantly higher than in normal ALDHhi/CD34+ cells. Reduction of JHDM1B expression in AML cells inhibited cell proliferation compared to control cells, through induction of G1 cell cycle arrest, an increase in the p15Ink4b mRNA and protein expression. JHDM1B mRNA was overexpressed in all 133 AML clinical specimens tested (n = 22, 57, 34, and 20 for M1, 2, 4, and 5 subtypes respectively). Compared to normal ALDHhi/CD34+ cells, JHDM1B gene expression was 1.57‐ to 1.87‐fold higher in AML‐derived ALDHhi/CD34+cells. Moreover, the JHDM1B protein was more strongly expressed in AML‐derived ALDHhi/CD34+ cells from compared to normal ALDHhi/CD34+ cells. In addition, depletion of JHDM1B reduced colony formation of AML‐derived ALDHhi/CD34+ cells due to induction of p15Ink4b expression through direct binding to p15Ink4b promoter and loss of demethylation of H3K36me2. In summary, we found that JHDM1B mRNA is predominantly expressed in AML‐derived ALDHhi/CD34+ cells, and that aberrant expression of JHDM1B induces AML cell proliferation through modulation of cell cycle progression. Thus, inhibition of JHDM1B expression represents an attractive target for AML therapy. © 2011 Wiley Periodicals, Inc.
Oligomycin A enhances apoptotic effect of TRAIL through CHOP‐mediated death receptor 5 expression
Authors: He Long , Jang Jae Hyuk , Choi Hyun Gil , Lee Sun Mi , Nan Mei Hua , Jeong Sook Jung , Dong Zigang , Kwon Yong Tae , Lee Kyung Sang , Lee Ki Won , Chung Jong Kyeong , Ahn Jong Seog , Kim Bo Yeon
Published: November 2011

Development of resistance to TNF‐related apoptosis‐inducing ligand (TRAIL) in tumor cells is one of the important problems in cancer treatment. Despite the previous report demonstrating that oligomycin suppressed TNF‐induced apoptosis, in our screening of small molecules enhancing cancer cell death to TRAIL, oligomycin A (OMA) was found to enhance TRAIL‐induced apoptosis in HeLa cells. CCAAT/enhancer‐binding protein homologous protein (CHOP) was found to directly bind to death receptor 5 (DR5) promoter through endoplasmic reticulum stress (ER‐stress) signaling and sensitize the cells to TRAIL. Among ER‐stress associated proteins, OMA triggered the inositol‐requiring enzyme 1 (IRE1) signaling pathway, leading to X‐binding protein 1 (XBP1) splicing, CHOP expression and DR5 upregulation. In contrast, small‐interfering RNA (siRNA) of CHOP reduced the number of apoptotic cells in response to the co‐treatment of TRAIL and OMA. Collectively, our data suggest that OMA enhances apoptotic death of cervical cancer cells to TRAIL through upregulation of CHOP‐mediated DR5 expression following ER‐stress. © 2011 Wiley Periodicals, Inc.
Androgen receptor signals regulate UDP‐glucuronosyltransferases in the urinary bladder: A potential mechanism of androgen‐induced bladder carcinogenesis
Authors: Izumi Koji , Zheng Yichun , Hsu Jong‐Wei , Chang Chawnshang , Miyamoto Hiroshi
Published: November 2011

UDP‐glucuronosyltransferases (UGTs), major phase II drug metabolism enzymes, play an important role in urinary bladder cancer initiation by detoxifying carcinogens. We aimed to determine if androgens regulate UGT expression via the androgen receptor (AR) pathway in the bladder. Real‐time reverse transcription‐polymerase chain reaction and Western blot analyses were used to assess UGT1A levels in the normal urothelium SVHUC cell line stably expressed with AR and in bladder tissues from AR knockout (ARKO) and castrated male mice. Immunohistochemistry was also performed in radical cystectomy specimens. Dihydrotestosterone (DHT) treatment in SVHUC‐AR reduced mRNA expression of all the UGT1A subtypes (19–75% decrease), and hydroxyflutamide antagonized the DHT effects. In contrast, DHT showed only marginal effects on UGT1A expression in SVHUC‐Vector. Of note were higher expression levels of UGT1As in SVHUC‐Vector than in SVHUC‐AR. In ARKO mice, all the Ugt1a subtypes were up‐regulated, compared to wild‐type littermates. In wild‐type male mice, castration increased the expression of Ugt1a8, Ugt1a9, and Ugt1a10. Additionally, wild‐type female mice had higher levels of Ugt1a than wild‐type males. Immunohistochemical studies showed strong (3+) UGT1A staining in 11/24 (46%) cancer tissues, which was significantly lower than in corresponding benign tissues [17/18 (94%) cases (P = 0.0009)]. These results suggest that androgen‐mediated AR signals promote bladder carcinogenesis by down‐regulating the expression of UGTs in the bladder. © 2011 Wiley Periodicals, Inc.
Automated QSAR with a Hierarchy of Global and Local Models
Authors: Wood David J. , Buttar David , Cumming John G. , Davis Andrew M. , Norinder Ulf , Rodgers Sarah L.
Published: November 2011

We present an automated QSAR procedure that is used in AstraZeneca’s AutoQSAR system. The approach involves automatically selecting the most predictive models from pools of both global and local models. The effectiveness of this QSAR modelling strategy is demonstrated with a retrospective study that uses a diverse selection of 9 early stage AstraZeneca drug discovery projects and 3 physicochemical endpoints: LogD; solubility and human plasma protein binding. We show that the strategy makes a statistically significant improvement to the accuracy of predictions when compared to an updating global strategy, and that the systematic biases inherent in the global model predictions are almost completely removed. This improvement is attributed to the model selection aspect of the strategy.
Boiling peanut Ara h 1 results in the formation of aggregates with reduced allergenicity
Authors: Blanc Fany , Vissers Yvonne M. , Adel‐Patient Karine , Rigby Neil M. , Mackie Alan R. , Gunning A. Patrick , Wellner Nikolaus K. , Skov Per S. , Przybylski‐Nicaise Laetitia , Ballmer‐Weber Barbara , Zuidmeer‐Jongejan Laurian , Szépfalusi Zsolt , Ruinemans‐Koerts Janneke , Jansen Ad P. H. , Bernard Hervé , Wal Jean‐Michel , Savelkoul Huub F. J. , Wichers Harry J. , Mills E. N. Clare
Published: November 2011

Scope: Roasting rather than boiling and Maillard modifications may modulate peanut allergenicity. We investigated how these factors affect the allergenic properties of a major peanut allergen, Ara h 1.

Methods and results: Ara h 1 was purified from either raw (N‐Ara h 1) or roasted (R‐Ara h 1) peanuts. Boiling (100°C 15 min; H‐Ara h 1) resulted in a partial loss of Ara h 1 secondary structure and formation of rod‐like branched aggregates with reduced IgE‐binding capacity and impaired ability to induce mediator release. Glycated Ara h 1 (G‐Ara h 1) formed by boiling in the presence of glucose behaved similarly. However, H‐ and G‐Ara h1 retained the T‐cell reactivity of N‐Ara h 1. R‐Ara h 1 was denatured, comprised compact, globular aggregates, and showed no evidence of glycation but retained the IgE‐binding capacity of the native protein.

Conclusion: Ara h 1 aggregates formed by boiling were morphologically distinct from those formed by roasting and had lower allergenic activity. Glycation had no additional effect on Ara h 1 allergenicity compared with heating alone. Taken together with published data on the loss of Ara h 2/6 from boiled peanuts, this supports the hypothesis that boiling reduces the allergenicity of peanuts.
The protective role of natural phytoalexin resveratrol on inflammation, fibrosis and regeneration in cholestatic liver injury
Authors: Chan Che‐Chang , Cheng Ling‐Yi , Lin Chin‐Lung , Huang Yi‐Hsiang , Lin Han‐Chieh , Lee Fa‐Yauh
Published: November 2011

Liver injuries can trigger a cascade of inflammatory responses and as a result, initiate the process of hepatic regeneration and fibrogenesis. Resveratrol (RSV) has multiple health‐promoting benefits. This study evaluated the potential protective effects and mechanism of RSV as related to cholestatic liver injury. RSV was given (4 mg/kg/day, i.p.) for either 3 days or 7 days after bile duct ligation (BDL) injury. RSV significantly reduced serum ALT, AST but not T‐bil on Day 3. At this early stage of injury, RSV significantly reduced TNF‐α and IL‐6 mRNA and decreased the number of Kupffer cells (CD68+) recruited in the injured liver. RSV decreased hepatic fibrosis and reduced collagen Iα1 and TIMP‐1 mRNA on Day 7. At the later stages of injury, RSV increased the number of Ki67+ hepatocytes indicating that RSV promoted hepatocyte proliferation. Additionally, it resulted in decreased expression of 4‐hydroxynonenal and increased expression of the hepatocyte growth factor protein and mRNA in the RSV‐treated BDL group. Meanwhile, RSV reduced the mortality rate of BDL mice. In conclusion, RSV attenuated inflammation and reduced Kupffer cells activation. RSV decreased fibrosis and promoted hepatocyte regeneration, which increased the survival of BDL mice. RSV was beneficial for the treatment of cholestatic liver injury.
Contrast at high field: Relaxation times, magnetization transfer and phase in the rat brain at 16.4 T
Authors: Pohmann Rolf , Shajan G. , Balla D. Z.
Published: November 2011

Parameter maps: Relaxation times T1, T2 and T*2, MTR and frequency for one exemplary slice. All images represent different rats and slice positions. All maps were generated by a pixel‐by‐pixel fit of the corresponding parameters; SNR differences are caused by the varying fitting accuracies. The arrows in the T*2 image (c) point out cortical veins. The increased MTR on the left side of image (d) is due to B1 inhomogeneity. From the article by Pohmann et al (pp 1572–1581).
Restricted additive Schwarz methods for Markov chains
Authors: Benzi Michele , Kuhlemann Verena
Published: November 2011

The restricted additive Schwarz method is adapted to the problem of computing the stationary probability distribution vector of large, sparse, and irreducible stochastic matrices. Inexact and two‐level variants are also considered as well as acceleration by Krylov subspace methods. The convergence properties are analyzed, and extensive numerical experiments aimed at assessing the effect of varying the number of subdomains and the amount of overlap are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation of high thermal conductive aluminum nitride/cyanate ester nanocomposite using a new macromolecular coupling agent
Authors: Zhang Mancheng , Gu Aijuan , Liang Guozheng , Yuan Li
Published: November 2011

Novel glycidyl methacrylate–butyl acrylate–maleic anhydride (GBM) terpolymers with different molecular weights were synthesized by radical polymerization and characterized using fourier transform infrared, nuclear magnetic resonance (1H‐NMR and 13 C‐NMR), and gel permeation chromatography. Each GBM terpolymer was used to modify aluminum nitride (AlN), and the modified AlN, coded as AlN(GBM), was added to 2,2′‐bis(4‐cyanatophenyl)isopropylidene (CE) resin for preparing composites. Composites based on original AlN or γ‐(2,3‐epoxypropoxy)propyltrimethoxysilane‐modified AlN (AlN(K)) were also prepared for comparison. Although GBM and γ‐(2,3‐epoxypropoxy)propyltrimethoxysilane have similar reactive groups, the results indicate that GBM shows more attractive integrated advantages, reflected by the fact that CE/AlN(GBM) composites have better thermal stability, higher thermal conductivity, and higher glass transition temperature than those of CE/AlN(K). These properties result from better dispersion of fillers, improved interfacial adhesion between fillers and CE resin, and increased cross‐linking density. This study demonstrates that the nature of the coupling agents is an important factor to develop high performance composites for cutting‐edge industries. Copyright © 2011 John Wiley & Sons, Ltd.
Improved mathematical modeling for the sheet reheat phase during thermoforming
Authors: Khan Sohail Akbar , Girard Patrick , Bhuiyan Nadia , Thomson Vince
Published: November 2011

In any thermoforming process, plastic sheet heating is the most important phase as it is responsible for final part quality as well as overall process efficiency and productivity. The goal of the study reported here was to improve existing mathematical models to accurately predict the temperature profile inside a heated sheet, where the model could be used to better control the overall thermoforming process. A mathematical model with temperature dependent, variable sheet material properties including density, thermal diffusivity, specific heat, and thermal conductivity was developed and validated against experimental data. Models with constant and variable plastic sheet properties were created, simulated, and compared in Matlab. The models were validated by experiments which obtained temperature profiles at different depths within a plastic sheet by inserting thermocouples and recording temperatures. Further, the effect of sheet color on heating was investigated by considering two extreme cases: white (transparent) and black (opaque) colored sheets, and the effect of oven air temperature and velocity on sheet heating was also investigated. Results indicated that a variable properties model was needed to control sheet reheating especially with narrow forming windows, and that the heating profiles required for colored and noncolored sheets were very different. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Nanoparticle encapsulation by a polymer via in situ polymerization in supercritical conditions
Authors: Esmaeili Babak , Chaouki Jamal , Dubois Charles
Published: November 2011

The encapsulation of aluminum nanoparticles by polyvinylidene fluoride (PVDF) was carried out in supercritical conditions via in situ polymerization. The aluminum particles possessed an average diameter of 43.7 nm. The presence of PVDF on the particles was validated by thermogravimetric analysis (TGA). This result was further approved by X‐ray photoelectron spectroscopy (XPS), which showed high intensity peaks of fluorine and carbon on the particles after the encapsulation process, which are associated with the presence of hydrocarbon‐based PVDF. As observed by transmission electron microscopy (TEM) images, the nanoparticles were uniformly coated by a polymer of a few nanometers in thickness. The results showed that there is a good consistency between the calculated thickness of the polymer coating and the results obtained by TEM. In addition, the effect of polymerization time on the kinetics of the reaction was investigated. Finally, it was found that the thickness of the polymer layer can be controlled by the duration of the encapsulation process. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Shear‐induced crystallization of isotactic polypropylene studied by simultaneous light intensity and rheological measurements
Authors: Tiang Jen Shueng , Dealy John M.
Published: November 2011

We investigate the effects of high shear rate and a melt‐insensitive, organophosphate nucleating agent on shear‐induced crystallization of four isotactic polypropylenes using a sliding plate rheometer under isothermal, low‐supercooling conditions. We used a bifurcated optical fiber probe to measure light intensity and a shear stress transducer to monitor the simultaneous viscoelastic response to small‐amplitude oscillatory shear. The two techniques complement each other; at early times of crystallization, large attenuation in the light intensity is observed, whereas during the later stages, a major change in the viscoelastic response occurs due to the growing volume fraction of spherulites. In contrast to quiescent crystallization, the nucleation pathway of nucleated polymers after a brief, strong shear is little influenced by the nucleating agent but strongly affected by molecular weight. The early kinetics of non‐nucleated polymers is more strongly enhanced by shear than that of nucleated polymers. Increasing either shear rate or strain accelerates crystallization, and we found the product of shear rate and strain to be useful for correlating our data. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Synthesis, characterization of an epoxy‐terminated carbosiloxane and its application as a modifier in epoxy systems
Authors: Kang Nianjun , Du Zhongjie , Li Hangquan , Zhang Chen
Published: November 2011

An epoxy‐terminated carbosiloxane has been designed and synthesized as a modifier to improve toughness and stiffness of epoxy resins simultaneously. The modifier was rubbery in nature and possessed several epoxy groups. When co‐cured with a conventional epoxy precursor, diglycidyl ether of bisphenol‐A (DGEBA), it would phase separate as individual domains and thus act as a toughener. Through participating in curing reaction with its multiple epoxy groups, the crosslinking density of the system was increased and thus resulted in reinforcing of cured epoxy system. The modifier was synthesized via hydrosilylation and cohydrolysis reactions. The chemical structures of the carbosiloxane were confirmed by FTIR and 1H NMR spectra. The cured epoxy products were characterized by dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), impact strength testing, and atomic force microscopy (AFM). POLYM. ENG. SCI., 2011. ©2011 Society of Plastics Engineers
The effects of radiation cross‐linking and process parameters on the behavior of polyamide 12 in vacuum thermoforming
Authors: Seefried A. , Drummer D.
Published: November 2011

Compared to amorphous thermoplastics, semi‐crystalline thermoplastics usually have a smaller processing range for thermoforming, due to their narrow temperature window for the transition from viscoelastic to viscous material behavior. On the other hand, semi‐crystalline thermoplastics offer superior properties for applications like ductility or chemical resistance. Within this article, modification of semi‐crystalline polyamide 12 by radiation cross‐linking with respect to its suitability for vacuum thermoforming as well as the effects of processing parameters and sheet thickness on the resulting strain distributions in thermoformed parts are shown. Experimental thermoforming processing studies in combination with digital image correlation measurements, thermo‐mechanical and elongational rheometry were performed to characterize the behavior of cross‐linked semi‐crystalline thermoplastics in the vacuum thermoforming process. POLYM. ENG. SCI., 2011. ©2011 Society of Plastics Engineers
Poly(lactic acid)/low‐density polyethylene blends and its nanocomposites based on sepiolite
Authors: Nuñez K. , Rosales C. , Perera R. , Villarreal N. , Pastor J.M.
Published: November 2011

Poly(lactic acid) (PLA) nanocomposite ternary blends based on unmodified sepiolite were prepared by melt blending using a corotating twin‐screw extruder. Two grafted polymers were used as compatibilizer agents, in an effort to increase the PLA tensile toughness. The influence of incorporating a low‐cost commodity low‐density polyethylene, as dispersed phase to the composites on thermal degradation, and rheological and tensile properties was studied. The morphology of the blends and composites was determined through transmission and scanning electron microscopy techniques. Results showed that the compatibilized blends prepared without clay have higher thermal degradation susceptibility and tensile toughness than those prepared with sepiolite and significant changes in complex viscosity and melt elasticity values were observed between them. The nanocomposite blends exhibited similar thermal degradation, lower tensile strength, and Young's modulus values and increased elongation at break and tensile toughness, complex viscosity, and storage modulus compared with those of the nanocomposite of PLA. These results are related to the clay dispersion, to the type of morphology of the different blends, to the localization of the sepiolite in the different phases, the thermomechanical degradation of the PLA matrix phase during melt blending and the grafting degree of the compatibilizers used. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Cavitation‐induced rupture in high‐density polyethylene copolymers
Authors: Ben Jar P.‐Y. , Muhammad Souvenir
Published: November 2011

Using cylindrical specimens with short gauge length, bulk cavitation is successfully generated in high‐density polyethylene copolymers (HDPE) under tensile loading. The bulk cavitation is generated without the presence of sharp notch, and therefore, crack growth is not involved in the rupture process. The bulk cavitation is investigated in two types of HDPE that have different molecular characteristics. Test results indicate that bulk cavitation can be introduced in both the types of HDPE, for which the loading level is most easily identified using plots of true axial stress versus stroke. The main difference in the rupture process occurs during the postcavitation stretch. Using specimens of sufficiently long gauge length, constitutive equations for the HDPEs are determined and applied to finite element modeling of specimens with short gauge length. The results show that the hydrostatic stress level in specimens of short gauge length is about twice as high as that in specimens of long gauge length, supporting the conclusion on bulk cavitation from rubber testing. For HDPE, this study shows that the rise of hydrostatic stress level leads to the suppression of necking, to allow the bulk cavitation to dominate the deformation process. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Identification of the bile salt binding site on ipad from Shigella flexneri and the influence of ligand binding on IpaD structure
Authors: Barta Michael L. , Guragain Manita , Adam Philip , Dickenson Nicholas E. , Patil Mrinalini , Geisbrecht Brian V. , Picking Wendy L. , Picking William D.
Published: November 2011

Type III secretion (TTS) is an essential virulence factor for Shigella flexneri, the causative agent of shigellosis. The Shigella TTS apparatus (TTSA) is an elegant nano‐machine that is composed of a basal body, an external needle to deliver effectors into human cells, and a needle tip complex that controls secretion activation. IpaD is at the tip of the nascent TTSA needle where it controls the first step of TTS activation. The bile salt deoxycholate (DOC) binds to IpaD to induce recruitment of the translocator protein IpaB into the maturing tip complex. We recently used spectroscopic analyses to show that IpaD undergoes a structural rearrangement that accompanies binding to DOC. Here, we report a crystal structure of IpaD with DOC bound and test the importance of the residues that make up the DOC binding pocket on IpaD function. IpaD binds DOC at the interface between helices α3 and α7, with concomitant movement in the orientation of helix α7 relative to its position in unbound IpaD. When the IpaD residues involved in DOC binding are mutated, some are found to lead to altered invasion and secretion phenotypes. These findings suggest that adoption of a DOC‐bound structural state for IpaD primes the Shigella TTSA for contact with host cells. The data presented here and in the studies leading up to this work provide the foundation for developing a model of the first step in Shigella TTS activation. Proteins 2011. © 2012 Wiley Periodicals, Inc.
Astragaloside IV Attenuates Complement Membranous Attack Complex Induced Podocyte Injury Through the MAPK Pathway
Authors: Zheng Rong , Deng Yueyi , Chen Yiping , Fan Junming , Zhang Minghua , Zhong Yifei , Zhu Rong , Wang Lin
Published: November 2011

Membranous nephropathy (MN) is the most common cause of idiopathic nephrotic syndrome in adults and the cause is known to be due to the injury of podocytes located in the glomeruli. Astragalus membranaceus has been used for the treatment of patients with MN in China for a long time. The beneficial effect of Astragalus membranaceus on proteinuria of patients with MN has been well documented. However, the mechanism of astragalus membranaceu in alleviation of MN is still not completely understood. Therefore, in the current study, we employed a podocyte injury model induced by complement membranous attack complex to examine the mechanism of astragalus membraneceus in the treatment of MN. We found that complement membranous attack complex could increase lactate dehydrogenase (LDH) release from podocytes and astragaloside IV (AS‐IV) could prevent LDH release from podocytes in a time‐ and dose‐dependent pattern. Moreover, AS‐IV restored podocyte morphology and cytoskeleton loss induced by complement membranous attack complex. Furthermore, AS‐IV was able to reduce phosphorylation of JNK and ERK1/2 induced by complement membranous attack complex. In conclusion, the mechanism of Astragalus membranaceus in the treatment of MN may be related to its attenuation of podocyte injury through regulation of cytoskeleton and mitogen activated protein kinase. Copyright © 2011 John Wiley & Sons, Ltd.
Cell‐Line Specific Protection by Berry Polyphenols Against Hydrogen Peroxide Challenge and Lack of Effect on Metabolism of Amyloid Precursor Protein
Authors: Papandreou Magdalini A. , Tsachaki Maria , Efthimiopoulos Spiros , Klimis‐Zacas Dorothy , Margarity Marigoula , Lamari Fotini N.
Published: November 2011

Amyloid precursor protein (APP) altered metabolism, Aβ‐overproduction/aggregation and oxidative stress are implicated in the development of Alzheimer's disease pathology. Based on our previous data indicating that administration of a polyphenol‐rich (PrB) blueberry extract (from wild Vaccinium angustifolium) is memory enhancing in healthy mice and in order to delineate the neuroprotective mechanisms, this study investigated the antioxidant effects of PrB in H2O2‐induced oxidative damage, Aβ peptide fibrillogenesis and APP metabolism. PrB suppressed H2O2‐initiated oxidation (DCF assay) and cell death (MTT assay) in SH‐SY5Y cells. Protective effects were observed on Chinese hamster ovary (CHO) cells overexpressing APP770 carrying the mutation Val717Phe only at high concentrations, while further damage on HEK293 cells was induced after co‐treatment with 250 µ m H2O2 and PrB in comparison with H2O2 alone. Using the thioflavine T assay, blueberry polyphenols inhibited Aβ‐aggregation (~70%, 15 µg/mL) in a time‐dependent manner, while in the CHOAPP770 cells it had no effect on APP metabolism as assessed by western blot. The results suggest that blueberry polyphenols exhibit antioxidant and/or pro‐oxidant properties according to the cellular environment and have no effect on APP metabolism. Copyright © 2011 John Wiley & Sons, Ltd.
Systematic fragmentation patterns of archaeal intact polar lipids by high‐performance liquid chromatography/electrospray ionization ion‐trap mass spectrometry
Authors: Yoshinaga Marcos Y. , Kellermann Matthias Y. , Rossel Pamela E. , Schubotz Florence , Lipp Julius S. , Hinrichs Kai‐Uwe
Published: November 2011

Archaea are ubiquitous and abundant microorganisms on Earth that mediate key global biogeochemical cycles. The headgroup attached to the sn‐1 position of the glycerol backbone and the ether‐linked isoprenoid lipids are among the diagnostic traits that distinguish Archaea from Bacteria and Eukarya. Over the last 30 years, numerous archaeal lipids have been purified and described in pure cultures. Coupled high‐performance liquid chromatography (HPLC) ion‐trap mass spectrometry (ITMS) now enables the detection and rapid identification of intact polar lipids in relatively small and complex samples, revealing a wide range of archaeal lipids in natural environments. Although major structural groups have been identified, the lack of a systematic evaluation of MS/MS fragmentation patterns has hindered the characterization of several atypical components that are therefore considered as unknowns. Here, we examined mass spectra resulting from lipid analysis of natural microbial communities using HPLC/electrospray ionization (ESI)‐ITMSn, and depicted the systematics in MS2 fragmentation of intact archaeal lipids. This report will be particularly useful for environmental scientists interested in a rapid and straightforward characterization of intact archaeal membrane lipids. Copyright © 2011 John Wiley & Sons, Ltd.
Position‐specific carbon isotope analysis of trichloroacetic acid by gas chromatography/isotope ratio mass spectrometry
Authors: Breider Florian , Hunkeler Daniel
Published: November 2011

Trichloroacetic acid (TCAA) is an important environmental contaminant present in soils, water and plants. A method for determining the carbon isotope signature of the trichloromethyl position in TCAA using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) was developed and tested with TCAA from different origins. Position‐specific isotope analysis (PSIA) can provide direct information on the kinetic isotope effect for isotope substitution at a specific position in the molecule and/or help to distinguish different sources of a compound. The method is based on the degradation of TCAA into chloroform (CF) and CO2 by thermal decarboxylation. Since thermal decarboxylation is associated with strong carbon isotope fractionation (ε = −34.6 ± 0.2‰) the reaction conditions were optimized to ensure full conversion. The combined isotope ratio of CF and CO2 at the end of the reaction corresponded well to the isotope ratio of TCAA, confirming the reliability of the method. A method quantification limit (MQL) for TCAA of 18.6 µg/L was determined. Samples of TCAA produced by enzymatic and non‐enzymatic chlorination of natural organic matter (NOM) and some industrially produced TCAA were used as exemplary sources. Significant different PSIA isotope ratios were observed between industrial TCAA and TCAA samples produced by chlorination of NOM. This highlights the potential of the method to study the origin and the fate of TCAA in the environment. Copyright © 2011 John Wiley & Sons, Ltd.
Continuous analysis of δ18O and δD values of water by diffusion sampling cavity ring‐down spectrometry: a novel sampling device for unattended field monitoring of precipitation, ground and surface waters
Authors: Munksgaard Niels C. , Wurster Chris M. , Bird Michael I.
Published: November 2011

A novel sampling device suitable for continuous, unattended field monitoring of rapid isotopic changes in environmental waters is described. The device utilises diffusion through porous PTFE tubing to deliver water vapour continuously from a liquid water source for analysis of δ18O and δD values by Cavity Ring‐Down Spectrometry (CRDS). Separation of the analysed water vapour from non‐volatile dissolved and particulate contaminants in the liquid sample minimises spectral interferences associated with CRDS analyses of many aqueous samples. Comparison of isotopic data for a range of water samples analysed by Diffusion Sampling‐CRDS (DS‐CRDS) and Isotope Ratio Mass Spectrometry (IRMS) shows significant linear correlations between the two methods allowing for accurate standardisation of DS‐CRDS data. The internal precision for an integration period of 3 min (standard deviation (SD) = 0.1 ‰ and 0.3 ‰ for δ18O and δD values, respectively) is similar to analysis of water by CRDS using an autosampler to inject and evaporate discrete water samples. The isotopic effects of variable air temperature, water vapour concentration, water pumping rate and dissolved organic content were found to be either negligible or correctable by analysis of water standards. The DS‐CRDS system was used to analyse the O and H isotope composition in short‐lived rain events. Other applications where finely time resolved water isotope data may be of benefit include recharge/discharge in groundwater/river systems and infiltration‐related changes in cave drip water. Copyright © 2011 John Wiley & Sons, Ltd.
Consistent predictable patterns in the hydrogen and oxygen stable isotope ratios of animal proteins consumed by modern humans in the USA
Authors: Chesson Lesley A. , Valenzuela Luciano O. , Bowen Gabriel J. , Cerling Thure E. , Ehleringer James R.
Published: November 2011

Published datasets of proteinaceous animal tissues suggest that co‐variation between amino acid hydrogen (δ2H) and oxygen (δ18O) isotope ratios is a common feature in systems where isotopic variation is driven by geographic or temporal variation in the δ2H and δ18O values of environmental water. This has led to the development of models relating tissue δ2H and δ18O values to those of water, with potential application in a number of fields. However, the strength and ubiquity of the influence of environmental water on protein isotope ratios across taxonomic groups, and thus the relevance of predictive models, is an open question. Here we report strong co‐variation of δ2H and δ18O values across a suite of terrestrial and aquatic animal meats purchased in American food markets, including beef, poultry (chicken and turkey), chicken eggs, pork, lamb, freshwater fish, and marine fish. Significant isotope co‐variation was not found for small collections of marine bivalves and crustaceans. These results imply that isotopic signals from environmental water were propagated similarly through most of the diverse natural and human‐managed foodwebs represented by our samples. Freshwater fish had the largest variation in δ2H and δ18O values, with ranges of 121 ‰ and 19.2 ‰, respectively, reflecting the large isotopic variation in environmental freshwaters. In contrast marine animals had the smallest variation for both δ2H (7 ‰ range, crustaceans) and δ18O (3.0 ‰ range, bivalves) values. Known‐origin beef samples demonstrated direct relationships between the variance of environmental water isotope ratios and that of collected meats. Copyright © 2011 John Wiley & Sons, Ltd.
A latent class method for the selection of prototypes using expert ratings
Authors: Miller William E.
Published: November 2011

Latent class analysis can be applied to the outcomes of expert ratings to select objects or subjects that are regarded as prototypical of a category in an ordinal classification system. During a pilot study, Monte Carlo simulations demonstrated that the probability of correct selection is larger when using latent class analysis than when using methods that rely on agreement statistics. Further improvements in the latent class results can also be achieved by applying affine transformations to latent class estimates of sensitivity and specificity. An application is presented that involves the selection of prototypical radiographs. Copyright © 2011 John Wiley & Sons, Ltd.
Size and power estimation for the Wilcoxon–Mann–Whitney test for ordered categorical data
Authors: Tang Yongqiang
Published: November 2011

We derive an exact variance method for the size and power calculation for the Wilcoxon–Mann–Whitney test for ordered categorical data. The O'Brien–Castelloe approximation implemented in SAS version 9.2 (SAS Institute Inc., Cary, NC, USA) is simplified. Simulation studies show that the exact variance approach tends to be more accurate than the O'Brien–Castelloe approximation and the Zhao–Rahardja–Qu method derived under local alternatives. Copyright © 2011 John Wiley & Sons, Ltd.
A general framework for estimating volume‐outcome associations from longitudinal data
Authors: French Benjamin , Farjah Farhood , Flum David R. , Heagerty Patrick J.
Published: November 2011

Recently, there has been much interest in using volume‐outcome data to establish causal associations between measures of surgical experience or quality and patient outcomes following a surgical procedure, such as coronary artery bypass graft, total hip replacement, and radical prostatectomy. However, there does not appear to be a standard approach to a volume‐outcome analysis with respect to specifying a volume measure and selecting an estimation method. We establish the recurrent marked point process as a general framework from which to approach a longitudinal volume‐outcome analysis and examine the statistical issues associated with using longitudinal data analysis methods to model aggregate volume‐outcome data. We review assumptions to ensure that linear or generalized linear mixed models and generalized estimating equations provide valid estimates of the volume‐outcome association. In addition, we provide theoretical and empirical evidence that bias may be introduced when an aggregate volume measure is used to address a scientific question regarding the effect of cumulative experience. We conclude with the recommendation that analysts carefully specify a volume measure that most accurately reflects their scientific question of interest and select an estimation method that is appropriate for their scientific context. Copyright © 2011 John Wiley & Sons, Ltd.