bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcome of post–liver transplant ischemic and nonischemic biliary stenoses treated with percutaneous interventions: The bologna experience
Authors: Giampalma Emanuela , Renzulli Matteo , Mosconi Cristina , Ercolani Giorgio , Pinna Antonio Daniele , Golfieri Rita
Published: October 2011

In liver transplantation (LT), biliary strictures (BSs) are among the most common complications. The aim of this study was to evaluate the efficacy of percutaneous treatments in the management of post-LT BSs. Between 1999 and 2007, 48 patients underwent percutaneous treatments for posttransplant BSs. We divided the population into 2 groups according to the cause [ischemic (n = 14) or nonischemic (n = 34)] and into further subgroups according to the site [anastomotic (n = 34) or nonanastomotic (n = 14)]. All patients were treated with bilioplasty; in 9 patients who were refractory to bilioplasty, metallic stents were implanted. A technical success rate of 90% was achieved without differences between the ischemic and nonischemic groups or between the anastomotic and nonanastomotic subgroups (P = 0.10). The major complication rate was 4%. The overall 1- and 3-year primary patency rates were 94% and 45%, respectively, and better results were found for patients with nonischemic stenoses versus patients with ischemic stenoses (P = 0.032). The overall secondary patency rates were 94% and 83% at 1 and 3 years, respectively, and there were no statistical differences between the ischemic and nonischemic groups or between the anastomotic and nonanastomotic groups. In the stent subgroup, the overall primary 1- and 2-year patency rates were 100% and 71%, respectively, and the secondary patency rates were 100% and 100%, respectively. In conclusion, a percutaneous approach is highly effective for the treatment of post-LT BSs, and the best results are obtained for patients with simple, nonischemic BSs (technical success rate = 94%, 3-year primary patency rate = 81%, 3-year secondary patency rate = 75%). For patients with ischemic BSs, closer follow-up and retreatment are more frequently needed to achieve secondary patency rates comparable to (or even better than) those for patients with nonischemic stenoses. Liver Transpl 18:177–187, 2012. © 2011 AASLD.
Use of living donor liver transplantation varies with the availability of deceased donor liver transplantation
Authors: Vagefi Parsia A. , Ascher Nancy L. , Freise Chris E. , Dodge Jennifer L. , Roberts John P.
Published: October 2011

The demographics of patients in the United States who undergo living donor liver transplantation (LDLT) versus patients who undergo deceased donor liver transplantation (DDLT) are interesting with respect to the demographics of the donor service areas (DSAs). We examined adult recipients of primary, non–status 1 liver-only transplants from 2003 to 2009. The likelihood of undergoing LDLT was compared to the likelihood of undergoing DDLT by multivariate logistic regression. We examined the adjusted odds ratio (OR) for undergoing LDLT versus DDLT for patients with the same diagnosis and blood type after we stratified the DSAs into quintiles by the median match Model for End-Stage Liver Disease (MELD) scores. LDLT was performed for 1497 of 32,927 liver transplants (4.5%). LDLT decreased in frequency by approximately 30% from 2003 to 2009. In comparison with DDLT recipients, LDLT recipients were younger and had higher albumin levels, lower body mass indices, and lower match MELD scores. Females had increased odds of LDLT in comparison with males (OR = 1.74, P < 0.001). Patients with MELD exception scores were less likely to undergo LDLT (OR = 0.22, P < 0.001). Patients with cholestatic liver disease (adjusted OR = 2.04, P < 0.001) or malignant neoplasms other than hepatocellular carcinoma (adjusted OR = 3.33, P < 0.001) were more likely than patients with hepatitis C virus to undergo LDLT. Other characteristics associated with decreased odds of LDLT were black race (adjusted OR = 0.41, P < 0.001) and government insurance (adjusted OR = 0.51, P < 0.001). LDLT was more frequent in DSAs with high median MELD scores; the adjusted OR for LDLT was 38 for the DSAs in the highest quintile (P < 0.001). In conclusion, there are significant differences associated with race, insurance, sex, MELD exceptions, and DSA MELD scores between patients who undergo LDLT and patients who undergo DDLT. These differences can be hypothesized to be driven in part by the relative availability of LDLT versus DDLT at both the patient level and the DSA level. Liver Transpl 18:160–165, 2012. © 2011 AASLD.
Preparation of Flexible and Elastic Poly(trimethylene carbonate) Structures by Stereolithography
Authors: Schüller‐Ravoo Sigrid , Feijen Jan , Grijpma Dirk W.
Published: October 2011

3D porous and non‐porous structures are designed and prepared by stereolithography using resins based on PTMC macromers. Tough, flexible network films prepared in this manner show E moduli of ≈3.8 MPa and high elongations at break >900%; tensile strengths are ≈4.2 MPa. These values increase with increasing PTMC macromer molecular weight. To reach suitable viscosities for processing, up to 45 wt% propylene carbonate is added as non‐reactive diluent. The solid specimens have compression moduli of 3.1–4.2 MPa, similar to the values determined in tensile testing. The built porous structures show porosities of 53–66% and average pore sizes of 309–407 µm. The compression moduli of the porous structures are significantly lower than those of the solid structures.

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Synthesis of Poly[(ethylene carbonate)‐co‐(ethylene oxide)] Copolymer by Phosphazene‐Catalyzed ROP
Authors: Yang Hongjun , Yan Manqing , Pispas Stergios , Zhang Guangzhao
Published: October 2011

Poly[(ethylene carbonate)‐co‐(ethylene oxide)] is synthesized by ROP of 1,3‐dioxolan‐2‐one using 1‐tert‐butyl‐4,4,4‐tris(dimethylamino)‐2,2‐bis[tris(dimethylamino)phosphoranylidenamino]‐2Λ5,Λ5‐catenadiphosphazene as the catalyst. NMR spectroscopy shows that the copolymer chain consists of EO‐EC‐EO‐EO sequences. GPC measurements indicate a PDI of 1.43–1.66 and show that the molecular weight increases with monomer conversion. Thermal analysis demonstrates that the copolymer is amorphous with a glass transition temperature of about –42 °C and an onset decomposition temperature of about 200 °C.
Multifunctional Poly(ϵ‐caprolactone)‐Forming Networks by Diels–Alder Cycloaddition: Effect of the Adduct on the Shape‐Memory Properties
Authors: Defize Thomas , Riva Raphaël , Jérôme Christine , Alexandre Michaël
Published: October 2011

Star‐shaped poly(ϵ‐caprolactone)s are functionalized by various dienes (furan and anthracene) and a dienophile (maleimide), and the kinetics of network formation by melt‐blending is compared for both Diels–Alder adducts. When curing at 60 °C, the anthracene–maleimide network forms more rapidly and gives rise to a more crosslinked material than with the furan–maleimide adduct. Shape‐memory properties of the networks are compared in terms of Diels–Alder adduct stability. Both materials exhibit excellent fixity and recovery ratios, but the relatively low retro Diels–Alder temperature of the furan–maleimide adduct perturbs the mechanical stability of the network during cyclic tensile testing between 0 and 60 °C, whereas the anthracene–maleimide adduct is shown to be stable up to 150 °C.
“Schizomorphic” Emulsion Copolymerization Particles
Authors: Weber Nancy , Tiersch Brigitte , Unterlass Miriam M. , Heilig Anneliese , Tauer Klaus
Published: October 2011

Cryo‐electron microscopy, atomic force microscopy, and light microscopy investigations provide experimental evidence that amphiphilic emulsion copolymerization particles change their morphology in dependence on concentration. The shape of the particles is spherical at solids content above 1%, but it changes to rod‐like, ring‐like, and web‐like structures at lower concentrations. In addition, the shape and morphology of these particles at low concentrations are not fixed but very flexible and vary with time between spheres, flexible pearl–necklace structures, and stretched rods.
Electromobility – challenges for structural durability
Authors: Martin D. , Hiebl A. , Krueger L.
Published: October 2011

In this lecture the challenges of testing the structural durability of electric vehicles are highlighted. The requirements and in particular differences in those for electric vehicles and cars with internal‐combustion engines are compared and illustrated. Current experiences with the MINI E and actual BMW hybrid cars are shown. Furthermore, testing concepts for specific electromobility components and their structural integration into the vehicle are explained. Finally an insight into possible future hybrid cars is presented.
Plant flavone apigenin inhibits HDAC and remodels chromatin to induce growth arrest and apoptosis in human prostate cancer cells: In vitro and in vivo study
Authors: Pandey Mitali , Kaur Parminder , Shukla Sanjeev , Abbas Ata , Fu Pingfu , Gupta Sanjay
Published: October 2011

Apigenin (4′,5,7,‐trihydroxyflavone), an anticancer agent, selectively toxic to cancer cells induces cell cycle arrest and apoptosis through mechanisms that have not been fully elucidated. Our studies indicate that apigenin‐mediated growth inhibitory responses are due to inhibition of class I histone deacetylases (HDACs) in prostate cancer cells. Treatment of PC‐3 and 22Rv1 cells with apigenin (20–40 µM) resulted in the inhibition of HDAC enzyme activity, specifically HDAC1 and HDAC3 at the protein and message level. Apigenin‐mediated HDAC inhibition resulted in global histone H3 and H4 acetylation, as well as localized hyperacetylation of histone H3 on the p21/waf1 promoter. A corresponding increase was observed in p21/waf1 and bax protein and mRNA expression after apigenin exposure, consistent with the use of HDAC inhibitor, trichostatin A. The downstream events demonstrated cell cycle arrest and induction of apoptosis in both cancer cells. Studies of PC‐3 xenografts in athymic nude mice further demonstrated that oral intake of apigenin at doses of 20 and 50 µg/mouse/d over an 8‐wk period resulted in a marked reduction in tumor growth, HDAC activity, and HDAC1 and HDAC3 protein expression at both doses of apigenin. An increase in p21/waf1 expression was observed in apigenin‐fed mice, compared to the control group. Furthermore, apigenin intake caused a significant decrease in bcl2 expression with concomitant increase in bax, shifting the bax/bcl2 ratio in favor of apoptosis. Our findings confirm for the first time that apigenin inhibits class I HDACs, particularly HDAC1 and HDAC3 and its exposure results in reversal of aberrant epigenetic events that promote malignancy. © 2011 Wiley Periodicals, Inc.
Assessment of three epigenotypes in colorectal cancer by combined bisulfite restriction analysis
Authors: Karpinski Pawel , Szmida Elzbieta , Misiak Blazej , Ramsey David , Leszczynski Przemyslaw , Bebenek Marek , Sedziak Tomasz , Grzebieniak Zygmunt , Jonkisz Anna , Lebioda Arleta , Sasiadek Maria M.
Published: October 2011

Recent investigations have demonstrated the clear heterogeneity of sporadic colorectal cancer (CRC) with regard to CpG island methylation. Two unsupervised cluster analyses revealed that CRCs form three distinct DNA methylation subsets, which are referred to as the high‐, intermediate‐, and low‐methylation epigenotypes (HME, IME, and LME, respectively). A recent study by Yagi et al. found a fairly sensitive and specific identification of HME, IME, and LME using two marker panels analyzed by MALDI‐TOF mass spectrometry (MassARRAY). However, the expensive equipment required for this method substantially increases the cost and complexity of the assay. In this article, we demonstrate the assessment of HME, IME, and LME in a group of 233 sporadic CRCs using seven markers proposed by Yagi et al. The DNA methylation of each marker was quantified using combined bisulfite restriction analysis (COBRA) and analyzed along with various genetic factors associated with CRC [the BRAF and KRAS mutations, MLH1 methylation and microsatellite instability (MSI)]. The baseline methylation of each marker was generated from pooled DNA isolated from 50 normal colon tissues. We demonstrate that the correlation of HME, IME, and LME epigenotyped by COBRA using different molecular classifiers is similar to that achieved by MassARRAY. Therefore, epigenotyping CRCs using COBRA is a simple, specific, and cost‐effective method that has the potential to be widely used in CRC research. © 2011 Wiley Periodicals, Inc.
(15N ± 13C′) edited (4, 3)D‐H(CC)CONH TOCSY and (4, 3)D‐NOESY HNCO experiments for unambiguous side chain and NOE assignments of proteins with high shift degeneracy
Authors: Kumar Dinesh , Arora Ashish
Published: October 2011

Well‐resolved and unambiguous through‐bond correlations and NOE data are crucial for high‐quality protein structure determination by NMR. In this context, we present here (4, 3)D reduced dimensionality (RD) experiments: H(CC)CONH TOCSY and NOESY HNCO − which instead of 15N shifts exploit the linear combination of 15N(i) and 13C′(i‐1) shifts (where i is a residue number) to resolve the through‐bond 1H‐1H correlations and through‐space 1H‐1H NOEs. The strategy makes use of the fact that 15N and 13C′ chemical shifts when combined linearly provide a dispersion which is better compared to those of the individual chemical shifts. The extended dispersion thus available in these experiments will help to obtain the unambiguous side chain and accurate NOE assignments especially for medium‐sized alpha‐helical or partially unstructured proteins [molecular weight (MW) between 12–15 kDa] as well as higher MW (between 15–25 kDa) folded proteins where spectral overlap renders inaccurate and ambiguous NOEs. Further, these reduced dimensionality experiments in combination with routinely used 15N and 13C′ edited TOCSY and NOESY experiments will provide an alternative way for high‐quality NMR structure determination of large unstable proteins (with very high shift degeneracy), which are not at all amenable to 4D NMR. The utility of these experiments has been demonstrated here using 13C/15N labeled ubiquitin (76 aa) protein. Copyright © 2011 John Wiley & Sons, Ltd.
Solvent sensitivity of ortho substituent effect on 13C NMR chemical shift of the carboxyl carbon (δco) in benzoic acid
Authors: Sen Gupta Susanta K. , Shrivastava Ruchi
Published: October 2011

A reverse ortho effect is observed for the 13 C NMR chemical shifts of the carboxyl carbon (δco) in benzoic acids measured in aprotic solvents of varying polarity. The ortho effect on δco is best described by a combination of the reverse field and steric accelerating effects of the substituent in an 80: 20 pattern in apolar aprotic solvents and a 60: 40 pattern in dipolar aprotic ones. Interestingly, no good enough correlation was found between δco and log k1 of the acids measured in similar solvents. A critical analysis of the results clearly indicates the use of an apolar aprotic solvent and not a dipolar aprotic one as the solvent of choice for investigating intrinsic substituent effects on δc in an aromatic system. Copyright © 2011 John Wiley & Sons, Ltd.
Constant amplitude broadband refocusing pulses from numerical optimization
Authors: Brown Douglas
Published: October 2011

Broadband refocusing pulses for high‐field NMR can be constructed with broadband 90x pulses from numerical optimization of Bloch simulations concatenated with their time and phase reversed transformations. This work describes the search for minimal duration 18‐kHz modulation frequency constant amplitude refocusing pulses made in this manner for bandwidths of 40, 60 and 80 kHz. Variants optimized at multiple frequencies and with sine squared amplitude truncation also are described. The resulting pulses are expected to have immediate application especially for 13C refocusing in multidimensional experiments. Copyright © 2011 John Wiley & Sons, Ltd.
A spinning thermometer to monitor microwave heating and glass transitions in dynamic nuclear polarization
Authors: Miéville Pascal , Vitzthum Veronika , Caporini Marc A. , Jannin Sami , Gerber‐Lemaire Sandrine , Bodenhausen Geoffrey
Published: October 2011

As previously demonstrated by Thurber and Tycko, the peak position of 79Br in potassium bromide (KBr) allows one to determine the temperature of a spinning sample. We propose to adapt the original design by using a compact KBr tablet placed at the bottom of the magic angle spinning rotor, separated from the sample under investigation by a thin disk made of polytetrafluoroethylene (or ‘Teflon’®). This design allows spinning the sample up to at least 16 kHz. The KBr tablet can remain in the rotor when changing the sample under investigation. Calibration in the range of 98 < T < 320 K has been carried out in a static rotor by inserting a platinum thermometer. The accuracy is better than ± 0.9 K, even in the presence of microwave irradiation. Irradiation with 5 W microwaves at 263 GHz leads to a small temperature increase of 3.6 ± 1.4 K in either static or spinning samples. The dynamic nuclear polarization enhancement decreases with increasing temperature, in particular when a frozen glassy sample undergoes a glass transition. Copyright © 2011 John Wiley & Sons, Ltd.
Study of stereospecificity of 1H, 13C, 15N and 77Se shielding constants in the configurational isomers of the selenophene‐2‐carbaldehyde azine by NMR spectroscopy and MP2‐GIAO calculations
Authors: Afonin Andrei V. , Pavlov Dmitry V. , Albanov Alexander I. , Levanova Ekaterina P. , Levkovskaya Galina G.
Published: October 2011

In the 1H and 13C NMR spectra of selenophene‐2‐carbaldehyde azine, the 1H‐5, 13C‐3 and 13C‐5 signals of the selenophene ring are shifted to higher frequencies, whereas those of the 1H‐1, 13C‐1, 13C‐2 and 13C‐4 are shifted to lower frequencies on going from the EE to ZZ isomer or from the E moiety to the Z moiety of EZ isomer. The 15N chemical shift is significantly larger in the EE isomer relative to the ZZ isomer and in the E moiety relative to the Z moiety of EZ isomer. A very pronounced difference (60–65 mg/g) between the 77Se resonance positions is revealed in the studied azine isomers, the 77Se peak being shifted to higher frequencies in the ZZ isomer and in the Z moiety of EZ isomer. The trends in the changes of the measured chemical shifts are reasonably reproduced by the GIAO calculations at the MP2 level of the 1H, 13 C, 15 N and 77Se shielding constants in the energy‐favorable conformation with the syn orientation of both selenophene rings relative to the C = N groups. The NBO analysis suggests that such an arrangement of the selenophene rings may take place because of a higher energy of some intramolecular interactions. Copyright © 2011 John Wiley & Sons, Ltd.
Spectroscopic imaging using concentrically circular echo‐planar trajectories in vivo
Authors: Furuyama Jon K. , Wilson Neil E. , Thomas M. Albert
Published: October 2011

An alternative to the standard echo‐planar spectroscopic imaging technique is presented, spectroscopic imaging using concentrically circular echo‐planar trajectories (SI‐CONCEPT). In contrast to the conventional chemical shift imaging data, the sampled data from each set of concentric rings were regridded into Cartesian space. Usage of concentric k‐space trajectories has the advantage of requiring significantly reduced slew rates than echo‐planar spectroscopic imaging, allowing for the collection of higher spectral bandwidths and opening the door for high‐bandwidth echo‐planar styled spectroscopic imaging at higher magnetic fields. Before two‐dimensional spatial and one‐dimensional spectral encoding, the volume of interest was localized using the standard point‐resolved spectroscopy sequence. The feasibility of using concentric k‐space trajectories is demonstrated, and the spatial profiles and representative spectra are compared with the standard echo‐planar spectroscopic imaging technique in a gray matter phantom containing metabolites at physiological concentrations and healthy human brain in vivo. The symmetric nature of the concentric circles also reduces the number of required excitations for a given resolution by a factor of two. Possible artifacts and limitations are discussed. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Passive trunk loading influences muscle activation during dynamic activity
Authors: Olson Michael W.
Published: October 2011

Introduction: Repetitive loading of the low back tissues induces tension relaxation with a corresponding variation in the myoelectric response of the neuromuscular system, which may influence low back health. The purpose of this study was to observe trunk muscle activities before and after a passive cyclic trunk flexion–extension exercise. Methods: Nineteen participants were subjected to sagittal plane loading of the low back tissues. These individuals performed toe‐touching before and over 1 hour after load termination. Results: Lumbar paraspinal activity cessation occurred significantly sooner over time during lumbar and pelvic flexion post‐loading, as compared with pre‐loading. Lumbar paraspinal activity then re‐initiated later in lumbar extension. There was no change in peak or average muscle activity during the procedures. Conclusions: It is apparent that passive loading of the viscoelastic lumbar tissues results in a prolonged neuromuscular adaptation, followed by possible neuromuscular compensation sustained within 1 hour of load termination. Muscle Nerve, 2011
Tibial motor nerve conduction studies: An investigation into the mechanism for amplitude drop of the proximal evoked response
Authors: Barkhaus Paul E. , Kincaid John C. , Nandedkar Sanjeev D.
Published: October 2011

Introduction:

The amplitude of the compound muscle action potential (CMAP) of abductor hallucis (AH) shows the largest drop with proximal stimulation of any routinely studied motor nerves. The cause has not been established.

Methods:

Four experiments of tibial motor nerve conduction in several healthy control subjects were performed using far‐field recordings, collision, H‐reflex, and intramuscular recordings of foot muscles.

Results:

The proximal CMAP showed a mean peak–peak amplitude of 66% (range 57–79%) compared with the distal response. Collision and H‐reflex recordings in AH did not show evidence of a contribution from the tibial‐innervated calf muscle. Needle electrode recordings of CMAPs showed consistently different latencies between different foot muscles. Conclusion: Our experiments indicate that temporal dispersion and phase cancellation between the distal tibial‐innervated foot muscles recorded by the E2 (i.e., reference) electrode can explain the drop in amplitude between the proximal and distal tibial evoked CMAP. Muscle Nerve, 2011
Frontal plane hip and ankle sensorimotor function, not age, predicts unipedal stance time
Authors: Allet Lara , Kim Hogene , Ashton‐Miller James , De Mott Trina , Richardson James K.
Published: October 2011

Introduction: Changes occur in muscles and nerves with aging. In this study we explore the relationship between unipedal stance time (UST) and frontal plane hip and ankle sensorimotor function in subjects with diabetic neuropathy. Methods: UST, quantitative measures of frontal plane ankle proprioceptive thresholds, and ankle and hip motor function were tested in 41 subjects with a spectrum of lower limb sensorimotor function ranging from healthy to moderately severe diabetic neuropathy. Results: Frontal plane hip and ankle sensorimotor function demonstrated significant relationships with UST. Multivariate analysis identified only composite hip strength, ankle proprioceptive threshold, and age to be significant predictors of UST (R2 = 0.73), explaining 46%, 24%, and 3% of the variance, respectively. Conclusions: Frontal plane hip strength was the single best predictor of UST and appeared to compensate for less precise ankle proprioceptive thresholds. This finding is clinically relevant given the possibility of strengthening the hip, even in patients with significant peripheral neuropathy. Muscle Nerve, 2012
Estimated cost of treating myasthenia gravis in an insured U.S. population
Authors: Guptill Jeffery T. , Sharma Bal K. , Marano Alex , Soucy Alison , Krueger Andrew , Sanders Donald B.
Published: October 2011

Introduction: In this study we estimated the costs paid by U.S. health plans for treating myasthenia gravis (MG) in 2009 and determined the major cost drivers. Methods: One hundred thirteen MG patients were matched by propensity scores with 339 non‐MG patients from a comprehensive health‐care insurance database. The mean annual costs paid by the health plan for treating MG, costs by place of service, and costs for intravenous immunoglobulin (IVIg) and plasma exchange were determined. Results: Mean annual costs paid by the health plan per MG patient were $20,190 (SEM $4,763) and costs attributable to treating MG were $15,675. Home health services accounted for 23% of MG patient costs and represented almost exclusively IVIg infusion costs. Six MG patients had a total of 136 outpatient IVIg infusions at an average annual cost of $109,463 ± $57,303. Conclusions: The estimated annual health plan paid costs for treating MG were $15,675. Home health services represented 23% of MG patient costs, largely driven by IVIg administration. Muscle Nerve, 2012
Transformation of complex internal structures of poly(ethylene oxide)/chitosan oligosaccharide electrospun nanofibers
Authors: Zhang Jianfeng , Nie Jun
Published: October 2011

Electrospun nanofibers with a core–shell structure or an internal microphase‐separated structure were obtained from a homogeneous solution using a conventional single‐nozzle electrospinning setup. Because of the poor miscibility of poly(ethylene oxide) (PEO) and chitosan oligosaccharide (CS), the two polymers will separate into a core–shell structure (PEO as core, CS as shell) or an internal microphase‐separated structure (PEO as discrete phase, CS as continuous phase) depending on the fraction of each component in the solution. Moreover, the core–shell structure transforms to the internal microphase‐separated structure with a continuous decrease of the PEO fraction. The reason for the transition of these internal structures can be attributed to the different phase separation mechanisms. For the core–shell structure, phase separation proceeds in a mechanism of nucleation and growth; however, the internal microphase‐separated structure results from spinodal decomposition. Therefore, wide‐angle X‐ray diffraction and differential scanning calorimetry were employed to investigate PEO crystallization. Since both PEO and CS are biocompatible polymers, together with being able to control the fiber internal structure (core–shell or microphase separation), these electrospun nanofibers will have a great future in the biomedical field. Copyright © 2011 Society of Chemical Industry
Shape memory segmented polyurethanes: dependence of behavior on nanocellulose addition and testing conditions
Authors: Auad María L , Richardson Tara , Hicks Marisa , Mosiewicki Mirna A , Aranguren Mirta I , Marcovich Norma E
Published: October 2011

The response of synthesized shape memory segmented polyurethanes (PUs) was affected by the addition of cellulose nanocrystals, as well as by the various conditions selected to carry out thermomechanical cyclic tests. The PUs were synthesized from an α‐hydro‐ω‐hydroxy‐poly(ethylene oxide), tolylene‐2,4‐diisocyanate and 1,4‐butanediol as chain extender. Nanocomposites were prepared by mixing a suspension of cellulose nanocrystals in N,N‐dimethylformamide with the thermoplastic PU dissolved in the same organic solvent. The thermal properties of the neat PU and resulting composites were examined using differential scanning calorimetry. It was found that cellulose addition increases the PU soft segment melting and crystallization temperatures and the degree of crystallinity of this phase. Shape memory behavior was studied using cyclic thermal tensile tests. Both neat PU and composites exhibit shape memory properties, with fixity and recovery values that depend on heating temperature, imposed deformation, deformation rate and nanofiller addition. Copyright © 2011 Society of Chemical Industry
Synthesis and characterization of polyimide/polyhedral oligomeric silsesquioxane nanocomposites containing quinolyl moiety
Authors: Govindaraj Balasubramani , Sundararajan Pudupadi , Sarojadevi Muthusamy
Published: October 2011

A series of functional polyhedral oligomeric silsesquioxane (POSS)/polyimide (PI) nanocomposites were prepared using a two‐step approach. First, octa(aminophenyl)silsesquioxane (OAPS) was mixed with poly(amic acid) (PAA) prepared by reacting bis(4‐amino‐3,5‐dimethylphenyl)‐3‐quinolylmethane and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride. Second, the resulting solution was subjected to thermal imidization. The well‐defined ‘hard particles’ (POSS) and the strong covalent bonds in the amide linkage between the carbon atom of the carboxyl side group in PAA and the nitrogen atom of the amino group in POSS lead to a significant improvement in the thermal and mechanical properties. Homogeneous dispersion of POSS cages in the PI is evident from scanning electron microscopy, which further confirms that the POSS molecule becomes an integral part of the organic‐inorganic inter‐crosslinked network system. Differential scanning calorimetry and dynamic mechanical analysis show that the glass transition temperatures of the POSS‐containing nanocomposites are higher than that of the corresponding neat PI system, owing to the significant increase of the crosslinking density in the PI/POSS nanocomposites. Increasing the concentration of OAPS in the PI networks decreases the dielectric constant. Pure PI and PI/POSS systems have good antimicrobial activity. Copyright © 2011 Society of Chemical Industry
Preventing and troubleshooting artefacts in saturation labelled fluorescence 2‐D difference gel electrophoresis (saturation DiGE)
Authors: McNamara Laura E. , Kantawong Fahsai A. , Dalby Matthew J. , Riehle Mathis O. , Burchmore Richard
Published: October 2011

Saturation DiGE is a powerful but challenging technique for the characterisation of changes in protein expression between two or more scarce samples. In this paper, measures to prevent and troubleshoot artefacts in the saturation DiGE workflow are discussed, with illustration of some examples as they may be encountered in gel images or analysis.
Optimization of cell lysis and protein digestion protocols for the analysis of HeLa S3 cells by LC‐MS/MS
Authors: Winter Dominic , Steen Hanno
Published: October 2011

In order to maximize the number of proteins identified from Hela S3 cell lysate we tested various cell lysis, protein precipitation and digestion protocols. First, we compared three different lysis buffers, two mechanical cell disruption methods and two precipitation methods. Then, we tested six different in‐solution digestion protocols, three different in‐gel digestion protocols and ten different peptide extraction protocols. The result is a proposal for an optimized protocol to prepare the whole cell lysate samples from HeLa S3 cells.
Identification of differentially expressed proteins in soybean nodules under phosphorus deficiency through proteomic analysis
Authors: Chen Zhijian , Cui Qiangqiang , Liang Cuiyue , Sun Lili , Tian Jiang , Liao Hong
Published: October 2011

Symbiotic nitrogen fixation is a high‐phosphorus demand process. Proteomic analysis was performed to identify the differentially expressed proteins in soybean nodules under phosphate starvation, and qRT‐PCR was subsequently conducted to examine the expression patterns of the genes encoding the identified proteins. There were 44 phosphate‐starvation responsive proteins identified from soybean nodules. Among them, 14 plant and 3 rhizobial proteins were up‐regulated, whereas 13 plant and 14 rhizobial proteins were down‐regulated by phosphate starvation. The qRT‐PCR assays verified that gene expression correlated with 11 of the 14 up‐regulated proteins from plants, but only 4 of 13 down‐regulated proteins were correlated to the expression of the corresponding genes, suggesting that most up‐regulated proteins may be controlled at the transcriptional level, whereas down‐regulated proteins were controlled at the post‐transcriptional level. Furthermore, a group of genes exhibited differential responses to phosphate starvation in nodules versus roots, suggesting that different adaptive responses might occur between roots and nodules. To our best knowledge, this is the first study to reveal differential protein profiles of nodules responding to phosphate starvation through proteomic analysis, which could result in a relatively comprehensive understanding of molecular mechanisms through which soybean nodules adapt to phosphorus stress.
A theoretical study on the bimolecular reactions encountered in the pyrolysis of acetamide
Authors: Altarawneh Mohammednoor , Altarawneh Khaled
Published: October 2011

Bimolecular reactions of acetamide with acetamide itself, acetimidic acid and acetic acid are investigated to account for the formation of the three major experimental products from the pyrolysis of acetamide, namely ammonia, acetic acid and acetonitrile. This mechanism involves bimolecular deammonation reactions to form acetamide anhydride, acetic anhydride and N‐acetyl acetamide, and the subsequent fragmentation of these intermediates into acetic acid and acetonitrile. It is found that the overall reaction barrier for the formation of the three major experimental products from the bimolecular reaction of acetamide with its enol form (acetimidic acid) amount to a 36.1 kcal/mol barrier. This barrier is in excellent agreement with the corresponding experimental data from the self‐condensation of acetamide. This finding stresses on the role of acetimidic acid as a major intermediate in the pyrolysis of acetamide. The calculated activation barriers for the two available pathways in the bimolecular reaction of acetamide and acetic acid into imide and N‐acetyl acetamide (36.3 kcal/mol and 24.0 kcal/mol) is in accord with the corresponding experimental activation energy of 30.1 kcal/mol for the autocatalytic reaction of acetamide with the acetic acid. Reaction rate constants are obtained for all plausible reactions. Kinetic data presented herein should be instrumental in building a robust model for the decomposition of N‐alkylated amides, that is, a major structural entity in biomass. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and optoelectronic properties of novel organosoluble polynorbornenes containing asymmetric pyrenyl and electroactive substituents via ring‐opening metathesis polymerization
Authors: Lian Wei‐Ren , Ho Crystal , Huang Ying‐Chi , Liao Yi‐An , Wang Kun‐Li , Liaw Der‐Jang , Lee Kueir‐Rarn , Lai Juin‐Yih
Published: October 2011

Novel polynorbornenes, poly(NBPYTPA), and poly(HNBPYTPA), containing chromophoric and electroactive groups were synthesized by ring‐opening metathesis polymerization using Grubbs' catalysts and followed hydrogenation, respectively. The glass transition temperatures (Tg) of poly(NBPYTPA) and hydrogenated poly(HNBPYTPA) were 195 and 165 °C, respectively. The 10% weight‐loss temperatures of hydrogenated poly(HNBPYTPA) and poly(NBPYTPA) were up to 465 and 420 °C, respectively. The photoluminescence emission spectra of poly(HNBPYTPA) showed strong solvatochromic property, revealing that poly(HNBPYTPA) underwent remarkable bathochromic shifts with an increase in solvent polarity. The cyclic voltammogram of poly(HNBPYTPA) film cast onto an indium tin oxide (ITO)‐coated glass substrate exhibited two reversible oxidation redox couples at 0.8 and 1.2 V versus Ag/Ag+ in acetonitrile solution. The electrochromic characteristics of poly(HNBPYTPA) showed reversibility, with color changes from yellow to blue and then to red upon the application of potentials from 0 to 1.3 V. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 000: 000–000, 2011
Chemical modification of poly(ethylene‐co‐methyl acrylate‐co‐maleic anhydride) for cathodic electrodepositions
Authors: Percec Simona , Howe Laurie , Li Jing , Bair Stephen
Published: October 2011

This study is concerned with the development of new polymers that could be deposited via cathodic electrocoating methods on metal surfaces. The synthetic strategy is based on the incorporation of cationic functionalities into commercial polymers. Polyalkyl acrylic or methacrylic ester copolymers were reacted with primary or secondary amines and aminoalkanols or their mixtures. Depending on the proportion of the acrylic or methacrylic ester in the starting material and the extent of the chemical modification, the resulting amide functionalized polymers are soluble or dispersible in water and could be used as aqueous dispersions for cathodic electrodepositions. Hindered amine catalysts, such as diazabicyclo[2.2.2]octane, accelerate the chemical transformation leading to higher level of functionalization. Among different amines screened, mixtures of oleylamine and ethanolamine proved to produce the best results. A poly(ethylene‐co‐methyl acrylate‐co‐maleic anhydride) [poly(E‐co‐MA‐co‐MAH)] was aminolyzed in solution with a mixture of 50/50 (mol % ratio) of oleylamine/ethanolamine and used to generate aqueous dispersions via phase inversion from methyl isobutyl ketone solutions. These dispersions exhibit particle sizes in the submicron range and zeta potential values indicating a good stability. They could be electrodeposited to give films of high elasticity according to the nanomechanical tests. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Relevance of Surface Modification of Polyamide 6.6 Fibers by Air Plasma Treatment on the Release of Caffeine
Authors: Labay Cédric , Canal José Mª , Canal Cristina
Published: October 2011

Polymer fabrics are used in different areas of pharmaceutical technology as sanitary materials or implants, which make them an interesting support for drug delivery. Low pressure plasma allows modifying the first nanometers on the surface of polymers without altering their bulk properties. The aim of the present work was to evaluate the use of plasma technology as an efficient tool to modify polyamide 6.6 fibers and its relevance on the incorporation and release of an active principle, in this case caffeine, from the materials. Therefore, surface modification of polyamide 6.6 (PA 66) fiber properties (wettability, chemical, and topographical properties) was evaluated under different plasma working conditions. It was shown that the thickness of a PDMS coating layer on the fibers was reduced as a function of plasma working conditions (increased air flow rate), and that surface functionalization of polyamide took place by oxygen‐containing moieties without any degradation or alteration in fiber topography. In vitro caffeine release showed that plasma gas flow increase improves significantly (up to 90% after 24 h) the delivery of active principle from the fabrics without altering the release mechanism from the PA 66 fabrics.

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Control of Wettability of Plasma Polymers by Application of Ti Nano‐Clusters
Authors: Kylián Ondřej , Polonskyi Oleksandr , Kratochvíl Jiří , Artemenko Anna , Choukourov Andrei , Drábik Martin , Solař Pavel , Slavínská Danka , Biederman Hynek
Published: October 2011

Two‐step process that allows controlling independently roughness and chemical composition of plasma polymers, i.e., two parameters determining the wettability of such materials, is presented. In the first step a film composed of Ti nano‐clusters is deposited on a smooth substrate. Nano‐cluster films of different roughness can be obtained depending on deposition time. In the second step the nano‐cluster films are overlaid by a thin layer of plasma polymer having the desired chemical structure. This approach allows the tuning of wettability of the deposited films to as much as 50% of the wettability of the films having the same chemical structure but deposited on a smooth substrate.

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Bronchodilator responsiveness in wheezy infants and toddlers is not associated with asthma risk factors
Authors: Debley Jason , Stanojevic Sanja , Filbrun Amy G. , Subbarao Padmaja
Published: October 2011

Background

There are limited data assessing bronchodilator responsiveness (BDR) in infants and toddlers with recurrent wheezing, and factors associated with a positive response.

Objectives

In a multicenter study of children ≤ 36 months old, we assessed the prevalence of and factors associated with BDR among infants/toddlers with recurrent episodes of wheezing.

Methods

Forced expiratory flows and volumes using the raised‐volume rapid thoracic compression method were measured in 76 infants/toddlers [mean (SD) age 16.8 (7.6) months] with recurrent wheezing before and after administration of albuterol. Prior history of hospitalization or emergency department treatment for wheezing, use of inhaled or systemic corticosteroids, physician treatment of eczema, environmental tobacco smoke exposure, and family history of asthma or allergic rhinitis were ascertained.

Results

Using the published upper limit of normal for post bronchodilator change (FEV0.5 ≥ 13% and/or FEF25–75 ≥ 24%) in healthy infants, 24% (n = 18) of children in our study exhibited BDR. The BDR response was not associated with any clinical factor other than body size. Dichotomizing subjects into responders (defined by published limits of normal) or by quartile to identify children with the greatest change from baseline (4th quartile vs. other) did not identify any other factor associated with BDR.

Conclusions

Approximately one quarter of infants/toddlers with recurrent wheezing exhibited BDR at their clinical baseline. However, BDR in wheezy infants/toddlers was not associated with established clinical asthma risk factors. Pediatr Pulmonol. 2012; 47:421–428. © 2011 Wiley Periodicals, Inc.
Proteomic changes induced by anaesthesia and muscle relaxant treatment prior to electroconvulsive therapy
Authors: Stelzhammer Viktoria , Rothermundt Matthias , Guest Paul C. , Michael Nikolaus , Sondermann Carina , Kluge Wolfgang , Martins‐de‐Souza Daniel , Rahmoune Hassan , Bahn Sabine
Published: October 2011

Purpose: Electroconvulsive therapy (ECT) is a psychiatric treatment in which seizures are electrically induced in patients. Prior to treatment, patients are usually given short‐acting anaesthetics and muscle relaxants to avoid harm, e.g. musculoskeletal injury, during the convulsions. However, most molecular studies investigating the mechanism of action of ECT have not explored the potential effects of the pre‐treatment with anaesthetic and/ or muscle relaxant.

Experimental design: We have carried out a targeted proteome analysis using multiplex immunoassay platform of serum samples before and 10 min after initiating the administration of the anaesthetic methohexital®and the muscle relaxant succinylcholine®to eight major depressive disorder patients undergoing ECT.

Results: Twenty‐six out of 142 analysed molecules showed significant differences in abundance after the methohexital/succinylcholine treatment. Importantly, eight of these molecules (fatty acid‐binding protein, insulin, interleukin (IL)1β, IL‐10, IL‐4, prolactin, S100 calcium‐binding protein B and tumor necrosis factor α) have been associated previously with effects of ECT.

Conclusions and clinical relevance: These findings indicate that caution should be used when interpreting results in existing and future proteome‐based biomarkers studies on the effects of ECT in neuropsychiatric disease or the use of anaesthetic/muscle relaxant in major surgical operations related to different therapeutic areas.
Berberine‐induced Haemolysis Revisited: Safety of Rhizoma coptidis and Cortex phellodendri in Chronic Haematological Diseases
Authors: Linn Yeh‐ching , Lu Jiahui , Lim Lay‐cheng , Sun Huili , Sun Jue , Zhou Yongming , Ng Han‐seong
Published: October 2011

Two commonly used berberine‐containing Chinese herbs, Rhizoma coptidis (RC) and Cortex phellodendri (CP), have been banned in Singapore for the past three decades due to implication of berberine in aggravating jaundice and kernicterus in neonates with glucose‐6‐phosphate dehydrogenase deficiency. Here we conducted a single arm, phase I/II clinical study on Chinese herbal medicine for patients with chronic cytopenic haematological conditions and we analysed a subset of 20 patients who also had RC, CP or both in their herbal concoction. We found no organ toxicity or electrolyte imbalance in these 20 patients where RC was administered for 1055 patient‐days and CP for 1252 patient‐days. In three patients with thalassemia intermedia, transient elevation in serum bilirubin level was observed but this was not associated with any aggravation of anaemia or liver dysfunction. A review of the literature found conflicting evidence of varying levels either supporting or refuting the allegation of neonatal jaundice and kernicterus caused by berberine. There were, however, very few clinical reports of adverse reaction attributable to RC or CP in oral TCM concoction. We conclude that based on traditional dosage and indication, the use of RC and CP in oral concoction is safe. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of Ligustrazine on Ureteral Obstruction‐induced Renal Tubulointerstitial Fibrosis
Authors: Yuan Xiao‐peng , Liu Long‐shan , Fu Qian , Wang Chang‐xi
Published: October 2011

Ligustrazine (LIG) is a purified and chemically identified component of the Chinese herb Ligusticum wallichii Franchat. It is a potent blocker of vasoconstriction and has strong scavenger of oxygen free radicals. We investigated the effect of LIG on renal tubulointerstitial fibrosis using a rat model of unilateral ureteral obstruction. Ligustrazine treatment significantly reduced the scores of interstitial collagen deposition, amounts of hydroxyproline, the density of myofibroblasts and macrophages, and amounts of transforming growth factor‐β1 (TGF‐β1) and connective tissue growth factor (CTGF) compared with their level in a saline‐treated control group. Using quantitative polymerase chain reaction we found that LIG treatment significantly reduced the mRNA expression of TGF‐β1, CTGF, monocyte chemoattractant protein‐1 and osteopontin. Moreover, the mRNA expression of hepatocyte growth factor and bone morphogenetic protein‐7 were significantly increased by LIG. In vitro, LIG inhibited the TGF‐β1‐induced loss of cytokeratin‐18 expression and de novo increase of the expression of α‐smooth muscle actin of HK‐2 cells in a dose‐dependent manner, which suggested that LIG could restrain the process of epithelial‐myofibroblast transition of tubular epithelial cells. This study indicates that LIG can attenuate renal tubulointerstitial fibrosis. It might be useful as a potential candidate in the treatment of chronic renal diseases. Copyright © 2011 John Wiley & Sons, Ltd.