bluuebunny/crossref_metadata_2025 huggingface dataset:
Bacterial biomass distribution in the global ocean
Authors: Buitenhuis E. T. , Li W. K. W. , Lomas M. W. , Karl D. M. , Landry M. R. , Jacquet S.
Published: May 2012

Abstract. We compiled a database of bacterial abundance of 39 766 data points. After gridding with 1° spacing, the database covers 1.3% of the ocean surface. There is data covering all ocean basins and depth except the Southern Hemisphere below 350 m or from April until June. The average bacterial biomass is 3.9 ± 3.6 μg l−1 with a 20-fold decrease between the surface and the deep sea. We estimate a total ocean inventory of about 1.3 × 1029 bacteria. Using an average of published open ocean measurements for the conversion from abundance to carbon biomass of 9.1 fg cell−1, we calculate a bacterial carbon inventory of about 1.2 Pg C. The main source of uncertainty in this inventory is the conversion factor from abundance to biomass. http://doi.pangaea.de/10.1594/PANGAEA.779142
Uncertainty in computations of the spread of warm water in a river – lessons from Environmental Impact Assessment
Authors: Kalinowska M. B. , Rowiński P. M.
Published: May 2012

Abstract. The present study aims at evaluation of sources of uncertainty in modelling of heat transport in a river caused by the discharge coming from a cooling system of a designed gas-stem power plant. This study was a part of Environmental Impact Assessment and was based on two-dimensional modelling of temperature distribution in an actual river. The problems with proper description of the computational domain, velocity field and hydraulic characteristics were considered in the paper. An in-depth discussion on the methods of evaluation of dispersion coefficients in the model comprising all four components of the dispersion tensor was carried out. Numerical methods and their influence on final results of computations were also discussed. All computations were based upon a real case study performed in Vistula River in Poland.
Visual and Refractive Outcome of Epi-LASIK for Myopia in Thin Corneas: a 12-Month Follow-Up
Authors: Cardona Genís , Sabino-Borreguero Sara , Juárez-Escalona Emilio , Fornieles Albert
Published: May 2012

Purpose.

A nonrandomized, retrospective, cohort, single-center study was designed to examine the visual and refractive outcome of epi–laser-assisted in situ keratomileusis (LASIK) for myopia (with and without astigmatism) in patients with thin corneas (less than 500 µm), and to compare these results with those of a group of patients with normal corneal thickness.

Methods.

Uncorrected distance visual acuity (UCVA), spherical and cylindrical residual refractive error, mean keratometry readings (Km), and pupil diameter were measured postoperatively at 24 hours, 1 week, 1 month, 3 months, and 12 months in a group of 28 eyes with thin corneas (group 1) and a second age- and gender-matched group of 28 eyes with normal corneal thickness (group 2). In addition, the efficacy index was calculated at every postoperative examination.

Results.

Postoperative central corneal thickness was 464.14±50.40 µm in group 1 and 421.89±26.63 µm in group 2 (p<0.001). No statistically significant difference was found in UCVA, efficacy index, and spherical and cylindrical residual error between both groups, with an evolution towards stability over time in all cases. Statistically significant between-group differences in Km at all follow-up examinations were explained by between-group differences in ablation depth and attempted spherical correction.

Conclusions.

A 12-month follow-up revealed epi-LASIK for myopia (with and without astigmatism) to be a safe and predictable surface ablation procedure, with good visual and refractive outcome in patients with thin corneas, as compared with a group of patients with normal corneal thickness.
Laparoscopic Management of Sacral Neurinoma Causing Hydronephrosis
Authors: Giona Simone , Oderda Marco , Garbossa Diego , Peraldo Francesca , Soria Francesco , Gurioli Alberto , Gontero Paolo
Published: May 2012

We report the case of a sacral neurinoma, which presented with mild hydronephrosis, due to compression of the right ureter, in a 71-yr old woman admitted to our hospital with recurrent urinary tract infections. CT and MRI detected a 4 x 4 cm mass pressing on the right ureter at the sacral level, in continuity with the second sacral foramen. Given this finding, the mass was thought to be of presumable neurogenic origin. In order to both reach a conclusive diagnosis and relieve the compression of the ureter, a laparoscopic resection of the mass was performed. Surgery was successful and the pathologic examination revealed a sacral Antoni A neurinoma. Neurinomas, also called Schwannomas, are uncommon benign nerve sheath tumors arising from Schwann cells. Their diagnosis can be extremely difficult due to their aspecific symptoms and the lack of pathognomonic characteristics on imaging exams. Therefore, histopathologic evaluation is essential in establishing the diagnosis. Surgical resection seems to be the best approach, both for diagnostic and therapeutic purposes.
Up from Memory:
Authors: Vivian Bradford J.
Published: May 2012

Booker T. Washington's Cotton States Exposition Address enlarges our understanding of the genre of witnessing by presenting a version of public testimony and historical remembrance sharply at odds with contemporary definitions of the genre. Washington's resolute choice to lend voice as a living witness to the atrocities of slavery in the service of conspicuously pragmatic and narrowly defined interests rather than universal human rights dramatically separates his performance of public witnessing from its late modern forms. Whereas survivors of historical atrocity in the post–World War II era ritually assume the difficult responsibility of testifying to past evils with the greatest possible accuracy, Washington relates the history of slavery—most notably its legacy of heinous human rights abuses—in radically inventive ways. The address demonstrates that those who embody the putative collective voice of subaltern communities may, in particular circumstances, call on the public to willfully forget, rather than somberly remember, the crimes of history. In doing so, the speech also suggests that the ability to bear witness may not automatically result in the ability to petition for equal human rights.
The Effects of Marine Cloud Brightening on Seasonal Polar Temperatures and the Meridional Heat Flux
Authors: Parkes Ben , Gadian Alan , Latham John
Published: May 2012

Marine cloud brightening (MCB) is one of several proposed solar radiation management (SRM) geoengineering schemes designed to ameliorate some of the undesirable effects of climate change, for example polar ice loss and associated increased sea levels. Satellite measurements over the last 40 years show a general reduction in polar sea ice area and thickness which is attributed to climate change.
In our studies, HadGEM1, a fully coupled climate model, is used to predict changes in surface temperatures and ice cover as a result of implementing MCB in a double carbon dioxide concentration atmosphere. The meridional heat flux (MHF) is the mechanism within the earth system for the transport of energy from tropical to polar regions. This poleward transport of heat in a double carbon dioxide atmosphere amplifies the effects in polar regions, where it has a significant impact on both temperatures and ice cover. The results from this work show that MCB is capable of roughly restoring control temperatures and ice cover (where control is defined as 440 ppm carbon dioxide, a predicted 2020 level) in a double carbon dioxide atmosphere scenario. This work presents the first results on the impact of MCB on the MHF and the ability of the MCB scheme to restore the MHF to a control level.
Scaffolding: Meaningful Sequences during the Training Phase of a Learning Potential Test?
Authors: van der Aalsvoort Geerdina M. , van Loo Floor , van Geert Paul
Published: May 2012

This study aimed at revealing scaffolding sequences of behavior during the training phase of a learning potential test. Involved were two conditions of four children with learning gains and four children without learning gains after the training phase of the subtest Classification of the Application of Cognitive Functions Scales. This subtest included three tasks: classification of color, form, and size. A dynamic system approach was used to describe the existence of four types of scaffolding that supposedly underlie the training phase. A microgenetic data analysis of the videotapes allowed coding of the behaviors of the training phase from the children and the diagnostician. Four sequences of scaffolding were defined, asking for attention of the child and giving attention as a child, asking for understanding of the child and responding to the diagnostician as a child; giving feedback to the child and responding to the feedback of the child, and offering strategies to the child and using strategies as a child. The results revealed no significant differences in the number of sequences between the conditions. Changes, however, were exposed in the relative frequency of each type of scaffolding from subtask 1 to 3. Moreover, the hierarchy of frequency of sequences differed between the conditions. The description of the findings of a boy from each condition in frequency per sequence, rainbow plot, and representative transcript revealed emergence of sequences over time. The findings are discussed with regard to theoretical reflections and methodological issues.
The Management of Type 2 Diabetic Patients with Hypoglycaemic Agents
Authors: Tsang Man-Wo
Published: May 2012

Type 2 Diabetes Mellitus (T2DM) is characterized by chronic hyperglycemia with disturbance in carbohydrate, lipid, and protein metabolism due to insulin resistance and beta cell dysfunction. Epidemiological studies have confirmed a global pandemic of T2DM, which has created an enormous burden on society, with regard to morbidity, mortality, and health care expenditures. Life style modifications are fundamental not only in early stages of disease management but need to be intensified as disease progresses. United Kingdom Prospective Diabetes Study (UKPDS) has demonstrated the progressive nature of T2DM, and as disease progresses, a combination agents—oral antidiabetic drugs (OAD) and insulin—are needed in order to maintain good sugar control. The general consensus of HbA1c target for most patients is less than 7%, and various guidelines and algorithms have provided guidance in patient management to keep patient at goal. As our understanding of pathophysiological defects advances, targeting treatment at underlying defects not only enables us to achieve HbA1c goal but also reduces morbidities, mortalities, and progression of the disease. Traditional oral agents like metformin and sulfonylureas have failed to arrest the progression of T2DM. New agents such as TZD, DPP-4 inhibitor, and SGLT-2 may increase our armamentariums against T2DM.
An Ensemble of Neural Classifiers and Constructivist Algorithms in the Identification of Agricultural Suitability Complexes of Soils on the Basis of Physiographic Information
Authors: Gruszczynski Stanislaw
Published: May 2012

The ensemble of classifiers for identification of agricultural suitability of soils on the basis of physiographic information was created in accordance with the stacking algorithm. It is comprised of five neural networks of various structures. The deciding element was a neural classifier optimised on the basis of input vectors composed of the indications of five classifiers making up the lower level. Among the architectures studied, the best result was achieved using the Radial Basis Function network as the decisive classifier, composed with the use of the constructivist Feature Space Mapping algorithm. In this configuration, the group correctly identified more than 99% of the elements of the validation set. The models may be used as tools for predicting expected soil condition, which is helpful in assessment of the range of substantial transformations.
Qualitative Analysis of a Cholera Bacteriophage Model
Authors: Das Prasenjit , Mukherjee Debasis
Published: May 2012

Cholera still remains as a severe global threat and is currently spreading in Africa and other parts of the world. The role of lytic bacteriophage as an intervention of cholera outbreaks is investigated using a mathematical model. Dynamics of cholera is discussed on basis of the basic reproduction number . Conditions of Hopf bifurcation are also derived for a positive net growth rate of Vibrio cholerae. Stability analysis and numerical simulations suggest that bacteriophage may contribute to lessening the severity of cholera epidemics by reducing the number of Vibrio cholerae in the environment. Hence with the presence of phage virus, cholera is self-limiting in nature. By using phage as a biological control agent in endemic areas, one may also influence the temporal dynamics of cholera epidemics while reducing the excessive use of chemicals. We also performed stochastic analysis which suggests that the model system is globally asymptotically stable in probability when the strengths of white noise are less than some specific quantities.
A Doubling Method for the Generalized Lambda Distribution
Authors: Headrick Todd C. , Pant Mohan D.
Published: May 2012

This paper introduces a new family of generalized lambda distributions (GLDs) based on a method ofdoublingsymmetric GLDs. The focus of the development is in the context ofL-moments andL-correlation theory. As such, included is the development of a procedure for specifying double GLDs with controlled degrees ofL-skew,L-kurtosis, andL-correlations. The procedure can be applied in a variety of settings such as modeling events and Monte Carlo or simulation studies. Further, it is demonstrated that estimates ofL-skew,L-kurtosis, andL-correlation are substantially superior to conventional product-moment estimates of skew, kurtosis, and Pearson correlation in terms of both relative bias and efficiency when heavy tailed distributions are of concern.
Two-Step Newton-Tikhonov Method for Hammerstein-Type Equations: Finite-Dimensional Realization
Authors: George Santhosh , Shobha Monnanda Erappa
Published: May 2012

Finite-dimensional realization of a Two-Step Newton-Tikhonov method
is considered for obtaining a stable approximate solution to nonlinear ill-posed Hammerstein-type operator equations KF(x)=f. Here F:D(F)⊆X→X is nonlinear monotone operator, K:X→Y is a bounded linear
operator, X is a real Hilbert space, and Y is a Hilbert space. The error analysis for this method is done under two general source conditions, the
first one involves the operator K and the second one involves the Fréchet
derivative of F at an initial approximation x0 of the the solution x̂: balancing principle of Pereverzev and Schock (2005) is employed in choosing
the regularization parameter and order optimal error bounds are established. Numerical illustration is given to confirm the reliability of our approach.
Multiple joint involvement in total knee replacement for osteoarthritis: Effects on patient‐reported outcomes
Authors: Perruccio A. V. , Power J. D. , Evans H. M. K. , Mahomed S. R. , Gandhi R. , Mahomed N. N. , Davis A. M.
Published: May 2012

Objective

To determine whether symptomatic (painful/problematic) joints pre–total knee replacement (TKR) surgery influence 1) pre‐ and 12‐month post‐TKR patient‐reported outcomes (pain, physical function, and mood [fatigue, anxiety, and depression]) and 2) postsurgical pain and function mediated through mood.

Methods

A total of 494 participants completed the patient‐reported outcome measures pre‐ and 12‐months post‐TKR. Symptomatic (painful/problematic) joints affected by arthritis were indicated on a homunculus presurgery. Covariate data included age, sex, educational attainment, body mass index, and comorbidity. Pre‐ and postsurgical outcome scores were regressed on symptomatic joint sites and covariates using linear regression analyses; postsurgical scores additionally were regressed on presurgery scores. Path analyses examined whether the effects of symptomatic joint sites on postsurgical pain and function were mediated through mood.

Results

The age range was 35–88 years (mean 65 years) and 65% were women. Forty‐six percent reported ≥4 symptomatic joints (other than the surgical knee). Pre‐ and postsurgery, worse outcome scores were observed with increasing joint count. Adjusted for covariates, individuals reporting symptomatic ankles/feet/toes, neck, and spine/lower back had worse presurgery fatigue and anxiety. Adjusted for covariates and presurgery status, worse fatigue for the neck and spine/lower back and worse depression, pain, and function for the ankles/feet/toes and neck were observed postsurgery. The influence of symptomatic ankles/feet/toes on postsurgical pain and function was in part direct and partially mediated through depression. Full mediation was found for the neck through fatigue, anxiety, and depression, and for the spine/lower back through fatigue.

Conclusion

Findings suggest that a comprehensive approach to osteoarthritis management/care is warranted, and identify important associations between symptomatic joints and mood that negatively impact post‐TKR pain and physical function.
Preparation of PTT/clay nanocomposites with solid‐state polymerized polytrimethylene terephthalate
Authors: Engelmann G. , Bonatz E. , Ganster J. , Pinnow M. , Bohn A.
Published: May 2012

To enhance the effectiveness of polytrimethylene terephthalate (PTT) for the preparation of clay‐based nanocomposites by melt intercalation and to upgrade the mechanical performance of these materials, solid‐state‐polymerization (SSP) experiments with neat PTT were carried out at 190, 200, and 210°C prior compounding to increase the average molecular weight and, based on this, the melt viscosity of this polymer. The progress of SSP was registered by time dependent sampling of intrinsic viscosity data. From this, activation energy of 180.6 kJ mol−1 was calculated. A characteristic sublimate formed during these SSP‐reactions was identified by mass‐spectroscopy to be a mixture of cyclic oligomers containing 2, 3, 4, and 5 monomeric units. The melt viscosity of neat PTT(SSP) could be increased from ∼ 460 to 15,000 Pa s−1. Therefore, tensile strength and Young's modulus were improved by 3.5 and 9%, respectively. Manufacturing of PTT(SSP) and the modified nanoclay was carried out with a corotating twin‐screw‐extruder at 230°C. A concentration of 3% of the inorganic filler component in the composites was aimed at. Compared with the data of virgin PTT, tensile strength, and modulus of the PTT(SSP)‐based nanocomposites could be enhanced by ∼ 9 and 40%, respectively. Additionally, a SSP‐reaction of the nanocomposite prepared with non‐pretreated PTT and nanoclay was performed at 210°C to test the robustness of the matrix polymer PTT against the influences of the nanofiller. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of poly(HEMA‐co‐MMA)‐g‐POSS nanocomposites by combination of reversible addition fragmentation chain transfer polymerization and click chemistry
Authors: Islam Md. Rafiqul , Bach Long Giang , Park Jong Myung , Hong Seong‐Soo , Lim Kwon Taek
Published: May 2012

New hybrid poly(hydroxyethyl methacrylate‐co‐methyl methacrylate)‐g‐polyhedral oligosilsesquioxane [poly(HEMA‐co‐MMA)‐g‐POSS] nanocomposites were synthesized by the combination of reversible addition fragmentation chain transfer (RAFT) polymerization and click chemistry using a grafting to protocol. Initially, the random copolymer poly(HEMA‐co‐MMA) was prepared by RAFT polymerization of HEMA and MMA. Alkynyl side groups were introduced onto the polymeric backbones by esterification reaction between 4‐pentynoic acid and the hydroxyl groups on poly(HEMA‐co‐MMA). Azide‐substituted POSS (POSSN3) was prepared by the reaction of chloropropyl‐heptaisobutyl‐substituted POSS with NaN3. The click reaction of poly(HEMA‐co‐MMA)‐alkyne and POSSN3 using CuBr/PMDEATA as a catalyst afforded poly(HEMA‐co‐MMA)‐g‐POSS. The structure of the organic/inorganic hybrid material was investigated by Fourier transformed infrared, 1H‐NMR, and 29Si‐NMR. The elemental mapping analysis of the hybrid using X‐ray photoelectron spectroscopy and EDX also suggest the formation of poly(HEMA‐co‐MMA)‐anchored POSS nanocomposites. The XRD spectrum of the nanocomposites gives evidence that the incorporation of POSS moiety leads to a hybrid physical structure. The morphological feature of the hybrid nanocomposites as captured by field emission scanning electron microscopy and transmission electron microscopic analyses indicate that a thick layer of polymer brushes was immobilized on the POSS cubic nanostructures. The gel permeation chromatography analysis of poly(HEMA‐co‐MMA) and poly(HEMA‐co‐MMA)‐g‐POSS further suggests the preparation of nanocomposites by the combination of RAFT and click chemistry. The thermogravimetric analysis revealed that the thermal property of the poly(HEMA‐co‐MMA) copolymer was significantly improved by the inclusion of POSS in the copolymer matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of positively charged composite nanofiltration membranes by coating poly(ether ether ketone) containing quaternary ammonium groups on polysulfone ultrafiltration membranes
Authors: Wang Jing , Wang Junhua , Wang Haifeng , Zhang Suobo
Published: May 2012

The novel positively charged poly(ether ether ketone)s (PEEKs) with pendant quaternary ammonium groups were synthesized by copolymerization of 3, 3′‐dimethylaminemethylene‐4,4′‐biphenol (DABP), 3,3′,4,4′‐tetramethylbiphenol, and 4,4′‐bisfluorobenzophenone followed by reaction with iodomethane. The resulting copolymers were used to prepare thin film composite (TFC) nanofiltration (NF) membranes via the dip‐coating method. The effects of different parameters such as copolymer concentration and curing time on the membrane performance (flux and rejection of inorganic salts) were investigated. The optimum parameters were that 1.5 wt % quaternary ammonium PEEK containing 1.8 quaternary ammonium groups per unit with 0.5 wt % DMSO coated on the polysulfone (PSf) support membrane and cured at 100°C. The results of the performance testing showed that the trend for rejection was R > R > RNaCl > R (R = rejection), which was a typical positively charged membrane. The best performance of these composite nanofiltration membranes was 91.3% rejection for 500 ppm MgCl2 and 62.5 L/m2 h water permeability at 0.4 MPa. The MWCO of the membrane was 800 Da. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Surface graft polymerization of conducting polyaniline on waterborne poyurethane‐urea film and its phenol sensing
Authors: Son Su‐Jin , Kim Han‐Seong , Lee Dong‐Jin , Lee Young‐Hee , Kim Han‐Do
Published: May 2012

Waterborne polyurethane‐ureas (pristine WBPUs: WBPU‐19 and WBPU‐24, fixed soft segment content: 60 wt %) containing dimethylol propionic acid (DMPA)/ethylene diamine (EDA) contents (19/16.8 and 24/11.4 mol %) were prepared. The polyaniline (PANI)‐graft‐WBPU (PANI‐graft‐WBPU) films were prepared by oxidative graft polymerization of aniline on the surface layer of WBPU films. This study focused on the effects of reaction conditions (concentrations/treating times/temperatures of aniline and APS) and DMPA content on the %grafting, conductivity, and mechanical properties of PANI‐graft‐WBPU films. To obtain the maximum %grafting (PANI‐graft‐WBPU‐19: 6.2, and PANI‐graft‐WBPU‐24: 7.4) and conductivity (PANI‐graft‐WBPU‐19: 3.6 × 10−2S/cm, and PANI‐graft‐WBPU‐24: 4.7 × 10−2S/cm), the optimum concentrations/treating times/temperatures of aniline and APS, were found to be 0.35M/10 min/25°C and 0.2M/10 min/0°C, respectively. The tensile strength of film samples was found to be increased in the order of PANI‐graft‐WBPU‐19>pristine WBPU‐19>PANI‐graft‐WBPU‐24>pristine WBPU‐24. The PANI‐graft‐WBPU‐19 (%grafting: 6.2) films on exposure to 0–10,000 ppm phenol solutions showed a well‐defined response behavior, demonstrating high promise for application in aqueous phenol sensors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Determining the mechanical properties of epoxy resin (DGEBA) composites by ultrasonic velocity measurement
Authors: Oral Imran , Guzel Hatice , Ahmetli Gulnare
Published: May 2012

In this study, the composites of diglycidyl ether of bisphenol A (DGEBA) epoxy resin that have been formed by mixing epoxy resin with allyl glycidyl ether (AGE) and 2,3‐epoxypropyl methacrylate [glycidyl methacrylate (GMA)] were prepared in weight % ratios of 90 : 10, 80 : 20, and 70 : 30. A computer controlled analyzer with 35 MHz and a digital oscilloscope with 60 MHz were used for measuring the velocities of ultrasonic wave. The measurement of ultrasonic velocity carried out by pulse echo method at frequencies of 2.25 and 3.5 MHz at room temperature. The values of acoustic impedance (Z), Poisson ratio (μ), and coefficients of elasticity (L, G, K, E) of composites were calculated by values of densities and velocities that obtained. Thus, the effect of modificating epoxy resin (DGEBA) by AGE and GMA on mechanical properties of DGEBA was investigated using the ultrasonic method. Atomic force microscopy has been used for determining the microstructure of composites. By the results obtained from the investigation, it have been established that the longitudinal and shear ultrasonic wave velocities, and the values of all the elasticity constants of DGEBA were increased by modification with AGE and GMA. Also the most suitable combination ratio for the compound of DGEBA : AGE and DGEBA : GMA has been found as 80 : 20. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of nanosilica ball—PMMA hybrid composites
Authors: Kim Heon Chang , Noh Seung Man , Park Seung‐Kyu
Published: May 2012

Organic–inorganic hybrid materials are one of the most attractive topics, which deals from fundamental researches to practical applications. In the present research, we have studied the polymerization of methyl methacrylate (MMA) on the surface of γ‐methacryloxy propyl trimethoxy silane (γ‐MPS) modified nanosilica ball (NSB). The polymeric materials were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and thermo gravimetric analysis (TGA). The results show that new core‐shell structured materials, NSB core‐PMMA shell composites, have been synthesized. The core‐shell hybrid materials can be adjusted to form only a single spherical phase. The addition of the core‐shell hybrid materials to the clearcoat enhances the surface hardness and antiscratch property. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Thermal conductivity of poly vinylidene fluoride composites filled with expanded graphite and carbon nanotubes
Authors: Shou Qing‐Liang , Cheng Ji‐Peng , Fang Ji‐Hong , Lu Fei‐Hong , Zhao Jia‐Jie , Tao Xin‐Yong , Liu Fu , Zhang Xiao‐Bin
Published: May 2012

The composites composed of Poly (vinylidene fluoride), expanded graphite (EG), and carbon nanotubes (CNTs) have been prepared by solution mixing, followed by compression. The structure of the composites was examined with scanning electron microscope and their electrical and thermal properties were investigated. About 1.2 wt % content of CNTs could present a percolated network in the polymer matrix, characterized by the electrical conductivity. The incorporation of EG and CNTs in the polymer caused an enhancement in thermal conductivity for the composites. However, a hybrid of EG and CNTs as filler of the polymer yielded a further improvement in thermal conductivity as compared to single component filler. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Bifunctional initiators on the polymerization of vinyl acetate
Authors: Galhardo Eduardo , Franco Cilene Meinberg , Lona Liliane M. F.
Published: May 2012

Initiators with functionality bigger than one can be used in free radical polymerization (FRP) to increase the polymerization rate without decreasing the molecular weight of the polymer. The use of bifunctional initiators to produce linear polymers (like polystyrene and Poly(methyl methacrylate) (PMMA)) can be found in the literature; however, their application to produce branched polymers is rarer. This work reports the effect of the bifunctional initiator Luperox 531 (1.4‐bi(t‐butyl‐carboperoxide) cyclehexane) on the FRP of vinyl acetate, which produces branched polymers. The monofunctional initiator Luperox TBEC (tert‐butylperoxide‐2‐etyhexil carbonate) is also used as base of comparison. Polymerizations in ampoules have been performed in different temperatures and initiator concentrations. Results were compared to those obtained from the styrene polymerization, which produces linear chains. It can be concluded that the effect of bifunctional initiators on FRP depends strongly on the kinetic mechanism, kind of monomer, and operating conditions adopted. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
CC Cross‐Coupling Reactions of O6‐Alkyl‐2‐Haloinosine Derivatives and a One‐Pot Cross‐Coupling/O6‐Deprotection Procedure
Authors: Gurram Venkateshwarlu , Pottabathini Narender , Garlapati Ramesh , Chaudhary Avinash B. , Patro Balaram , Lakshman Mahesh K.
Published: May 2012

Reaction conditions for the CC cross‐coupling of O6‐alkyl‐2‐bromo‐ and 2‐chloroinosine derivatives with aryl‐, hetaryl‐, and alkylboronic acids were studied. Optimization experiments with silyl‐protected 2‐bromo‐O6‐methylinosine led to the identification of [PdCl2(dcpf)]/K3PO4 in 1,4‐dioxane as the best conditions for these reactions (dcpf=1,1′‐bis(dicyclohexylphosphino)ferrocene). Attempted O6‐demethylation, as well as the replacement of the C‐6 methoxy group by amines, was unsuccessful, which led to the consideration of Pd‐cleavable groups such that CC cross‐coupling and O6‐deprotection could be accomplished in a single step. Thus, inosine 2‐chloro‐O6‐allylinosine was chosen as the substrate and, after re‐evaluation of the cross‐coupling conditions with 2‐chloro‐O6‐methylinosine as a model substrate, one‐step CC cross‐coupling/deprotection reactions were performed with the O6‐allyl analogue. These reactions are the first such examples of a one‐pot procedure for the modification and deprotection of purine nucleosides under CC cross‐coupling conditions.
Robust Exponential Stability of Discrete‐Time Delay Impulsive Systems with Parametric Uncertainties
Authors: Zhang Yu
Published: May 2012

This paper investigates robust exponential stability for discrete‐time delay impulsive systems with parametric uncertainties. The parametric uncertainties in the systems are assumed to be time varying and norm bounded. Using Lyapunov functionals, some robust exponential stability criteria are given. It is shown that the time interval between the nearest two impulses should be small enough, i.e., impulses must act frequently, when the impulses are employed to stabilize the original impulse‐free system that is not robustly stable. Conversely, when the original system without impulses is robustly stable, the time interval between the nearest two impulses should be large enough to let the system with impulsive perturbations retain its stability property. It should be noted that this is the first time that impulsive robust exponential stabilization results are given via Lyapunov functionals for discrete‐time uncertain delay impulsive systems. Some examples, including an example which cannot be studied by the existing results, are also presented to illustrate the effectiveness of the obtained results.
Passivity Analysis and Synthesis for a Class of Discrete‐Time Switched Stochastic Systems with Time‐Varying Delay
Authors: Lian Jie , Feng Zhi
Published: May 2012

This paper deals with the problems of passivity and passification for a class of discrete‐time switched stochastic systems with time‐varying delay. Based on the average dwell time approach, the piecewise Lyapunov function technique, and the free‐weighting matrix method, a new Lyapunov functional is proposed and sufficient conditions for mean‐square exponential stability and stochastic passivity are developed under average dwell time switching. Moreover, an estimate of state decay can be calculated in terms of linear matrix inequalities (LMIs). Then, the solvability condition for passification is established and the corresponding controller is designed. Two numerical examples are given to show the effectiveness of the proposed methods.
Decentralized Dynamic Coverage Control for Mobile Sensor Networks in a Non‐convex Environment
Authors: Song Cheng , Feng Gang , Wang Yong
Published: May 2012

In this paper, we consider the problem of decentralized dynamic coverage control for mobile sensor networks in an environment with unknown obstacles. The goal is to cover each point in the mission domain but outside the obstacles to a desired level. Each agent is modeled as a point mass based on Newton's law. A decentralized control strategy is developed to accomplish the dynamic coverage task without collision with obstacles. Discrete update of the cooperative coverage is also considered to enhance the cooperation of the agents in the fleet. The collision avoidance and global convergence of the proposed control scheme are proved and illustrated via a simulation example.
Combined effect of prenatal solvent exposure and GSTT1 or GSTM1 polymorphisms in the risk of birth defects
Authors: Garlantézec Ronan , Chevrier Cécile , Coiffec Isabelle , Celebi Catherine , Cordier Sylvaine
Published: May 2012

Exposure to solvents during pregnancy has long been suspected to increase the risk of congenital malformations. Glutathione S‐transferases (GSTs) are enzymes essential for the detoxification of various chemicals. Our objective here was to assess whether GST polymorphisms might modify the association between maternal solvent exposure and the risk of birth defects. A prospective cohort included 3421 pregnant women in Brittany, France (2002–2006). Occupational exposure to solvents was assessed from a job‐exposure matrix. Congenital malformations were diagnosed among livebirths, stillbirths, and medical pregnancy terminations. Using a nested case‐control design, 32 babies with major birth defects were compared to 348 normal births for babies' cord blood genotypes (at GSTT1 and GSTM1) and maternal occupational solvent exposure. Logistic models were used to adjust for potential confounders. The risk of major defects increased significantly in women with solvent exposure (20% of controls and 34% of cases). Frequencies of the null genotype of both the GSTT1 and GSTM1 genes were similar among controls and cases. There was a significantly increased risk of birth defects in GSTM1 not‐null cord‐blood genotype in pregnancies exposed to solvents (odds ratio [OR], 1.0 for not‐null, not‐exposed; OR, 4.0 for not‐null, exposed; 95% confidence interval [CI], 1.4–11.2; OR, 1.6 for null, not‐exposed; 95% CI, 0.6–3.9; OR, 1.0 for null, exposed; 95% CI, 0.2–4.7; p = 0.05). This nested case‐control study suggests that the child's GSTM1 genotype modifies the risk of major birth defects among offspring of solvent‐exposed women. Replication and additional investigations are necessary to confirm and elucidate these findings. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.
Peptoid–Peptide Hybrid Ligands Targeting the Polo Box Domain of Polo‐Like Kinase 1
Authors: Liu Fa , Park Jung‐Eun , Qian Wen‐Jian , Lim Dan , Scharow Andrej , Berg Thorsten , Yaffe Michael B. , Lee Kyung S. , Burke Terrence R.
Published: May 2012

We replaced the amino terminal Pro residue of the Plk1 polo‐box‐domain‐binding pentapeptide (PLHSpT) with a library of N‐alkyl‐Gly “peptoids”, and identified long‐chain tethered phenyl moieties giving greater than two‐orders‐of‐magnitude affinity enhancement. Further simplification by replacing the peptoid residue with appropriate amides gave low‐nanomolar affinity N‐acylated tetrapeptides. Binding of the N‐terminal long‐chain phenyl extension was demonstrated by X‐ray co‐crystal data.
Encapsulation of TCNQ and the Acridinium Ion within a Bisporphyrin Cavity: Synthesis, Structure, and Photophysical and HOMO–LUMO‐Gap‐Mediated Electron‐Transfer Properties
Authors: Chaudhary Arvind , Rath Sankar Prasad
Published: May 2012

The encapsulation of tetracyanoquinodimethane (TCNQ) and fluorescent probe acridinium ions (AcH+) by diethylpyrrole‐bridged bisporphyrin (H4DEP) was used to investigate the structural and spectroscopic changes within the bisporphyrin cavity upon substrate binding. X‐ray diffraction studies of the bisporphyrin host (H4DEP) and the encapsulated host–guest complexes (H4DEP⋅TCNQ and [H4DEP⋅AcH]ClO4) are reported. Negative and positive shifts of the reduction and oxidation potentials, respectively, indicated that it was difficult to reduce/oxidize the encapsulated complexes. The emission intensities of bisporphyrin, upon excitation at 560 nm, were quenched by about 65 % and 95 % in H4DEP⋅TCNQ and [H4DEP⋅AcH]ClO4, respectively, owing to photoinduced electron transfer from the excited state of the bisporphyrin to TCNQ/AcH+; this result was also supported by DFT calculations. Moreover, the fluorescence intensity of encapsulated AcH+ (excited at 340 nm) was also remarkably quenched compared to the free ions, owing to photoinduced singlet‐to‐singlet energy transfer from AcH+ to bisporphyrin. Thus, AcH+ acted as both an acceptor and a donor, depending on which part of the chromophore was excited in the host–guest complex. The electrochemically evaluated HOMO–LUMO gap was 0.71 and 1.42 eV in H4DEP⋅TCNQ and [H4DEP⋅AcH]ClO4, respectively, whilst the gap was 2.12 eV in H4DEP. The extremely low HOMO–LUMO gap in H4DEP⋅TCNQ led to facile electron transfer from the host to the guest, which was manifested in the lowering of the CN stretching frequency (in the solid state) in the IR spectra, a strong radical signal in the EPR spectra at 77 K, and also the presence of low‐energy bands in the UV/Vis spectra (in the solution phase). Such an efficient transfer was only possible when the donor and acceptor moieties were in close proximity to one another.
Enantioselectivity in degradation and transformation of quizalofop‐ethyl in soils
Authors: Li Zhaoyang , Li Qiaoling , Cheng Fengning , Zhang Wenshu , Wang Weixiao , Li Jingyin
Published: May 2012

The enantioselective degradation of quizalofop‐ethyl and its metabolite quizalofop‐acid in two soils, a Wuhan acidic soil and a Baoding alkaline soil, was investigated. The dissipation of quizalofop‐ethyl consisted of two phases, a rapidly deceasing first phase that lasted 1 day and a slowly decreasing second phase that extended till the end of the incubation. It is shown that S‐quizalofop‐ethyl degraded slightly faster than R‐quizalofop‐ethyl in the two soils. Further incubation of enantiopure enaniomers showed that quizalofop‐ethyl was configurationally stable in soil. Quizalofop‐acid was produced quickly, and its amount reached a maximum at 1–6 days time and then decreased slowly with half‐lives ranging from 11 to 21 days. The results also showed that quizalofop‐acid degraded faster in the acidic Wuhan soil than in the alkaline Baoding soil. At last, significant enantiomerization from S‐quizalofop‐acid to R‐quizalofop‐acid was observed, and the enantiomerization was fast, resulting in residues enriched with R‐quizalofop‐acid whatever racemic quizalofop‐ethyl or pure enantiomers were initially applied in the soils. Chirality 24:552–557, 2012. © 2012 Wiley Periodicals, Inc.
Clinical and proteomic characterization of acute myeloid leukemia with mutated RAS
Authors: Kadia Tapan M. , Kantarjian Hagop , Kornblau Steven , Borthakur Gautam , Faderl Stefan , Freireich Emil J. , Luthra Raja , Garcia‐Manero Guillermo , Pierce Sherry , Cortes Jorge , Ravandi Farhad
Published: May 2012

BACKGROUND:

Activating mutations in RAS are frequently present in patients with acute myeloid leukemia (AML), but their overall prognostic impact is not clear.

METHODS:

A retrospective analysis was performed to establish the clinical characteristics of patients with RAS‐mutated (RASmut) AML, to analyze their outcome by therapy, and to describe the proteomic profile of RASmut compared with wild‐type RAS (RASWT) AML.

RESULTS:

Of 609 patients with newly diagnosed AML, 11% had RASmut. Compared with RASWT, patients with RASmut AML were younger (median age, 54 years vs 63 years; P = .001), had a higher white blood cell count (16K mm−3 vs 4K mm−3 ; P < 0.001) and bone marrow blast percentage (56% vs 42%; P = .01) at diagnosis, and were less likely to have an antecedent hematologic disorder (36% vs 50%; P = .03). The inv(16) karyotype was overrepresented in patients with RASmut and the −5 and/or −7 karyotype was underrepresented. RAS mutations were found to have no prognostic impact on overall survival or disease‐free survival overall or within cytogenetic subgroups. There was a suggestion that patients with RASmut benefited from cytarabine (AraC)‐based therapy. Proteomic analysis revealed simultaneous upregulation of the RAS‐Raf‐MAP kinase and phosphoinositide 3‐kinase (PI3K) signaling pathways in patients with RASmut.

CONCLUSIONS:

RAS mutations in AML may delineate a subset of patients who benefit from AraC‐based therapy and who may be amenable to treatment with inhibitors of RAS and PI3K signaling pathways. Cancer 2012. © 2012 American Cancer Society.
Association of EGFR mutation or ALK rearrangement with expression of DNA repair and synthesis genes in never‐smoker women with pulmonary adenocarcinoma
Authors: Ren Shengxiang , Chen Xiaoxia , Kuang Peng , Zheng Limou , Su Chunxia , Li Jiayu , Li Bing , Wang Yongshen , Liu Lu , Hu Qiong , Zhang Jie , Tang Liang , Li Xuefei , Zhou Caicun , Schmid‐Bindert Gerald
Published: May 2012

BACKGROUND:

Epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) rearrangement may predict the outcome of targeted drug therapy and also are associated with the efficacy of chemotherapy in patients with nonsmall cell lung cancer (NSCLC). The authors of this report investigated the relation of EGFR mutation or ALK rearrangement status and the expression of DNA repair or synthesis genes, including excision repair cross‐complementing 1 (ERCC1), ribonucleotide reductase subunit M1 (RRM1), thymidylate synthetase (TS), and breast cancer‐early onset (BRCA1), as a potential explanation for these observations.

METHODS:

In total, 104 resected lung adenocarcinomas from women who were nonsmokers were analyzed concurrently for EGFR mutations, ALK rearrangements, and mRNA expression of the ERCC1, RRM1, TS, and BRCA1 genes. EGFR mutations were detected with a proprietary detection kit, ALK rearrangements were detected by polymerase chain reaction analysis, and genetic mRNA expression was detected by real‐time polymerase chain reaction analysis.

RESULTS:

Of 104 patients, 73 (70.2%) had EGFR mutations, and 10 (9.6%) had ALK rearrangements. ERCC1 mRNA levels in patients who had EGFR mutations were 3.44 ± 1.94 × 10−3, which were significantly lower than the levels in patients who were positive for ALK rearrangements and in patients who were negative for both biomarkers (4.60 ± 1.95 × 10−3 and 4.95 ± 2.33 × 10−3, respectively; P = .010). However, TS mRNA levels were significantly lower in patients who had EGFR mutations (1.15 ± 1.38 × 10−3 vs 2.69 ± 3.97 × 10−3; P = .006) or ALK rearrangements (1.21 ± 0.78 × 10−3 vs 2.69 ± 3.97 × 10−3; P = .020) than in patients who were negative for both biomarkers.

CONCLUSIONS:

NSCLC specimens that harbored activating EGFR mutations were more likely to express low ERCC1 and TS mRNA levels, whereas patients with NSCLC who had ALK rearrangement were more likely to express low TS mRNA levels. Cancer 2012. © 2012 American Cancer Society.
Interleukin‐13 receptor alpha2 is a novel therapeutic target for human adrenocortical carcinoma
Authors: Jain Meenu , Zhang Lisa , He Mei , Patterson Erin E. , Nilubol Naris , Fojo Antonio T. , Joshi Bharat , Puri Raj , Kebebew Electron
Published: May 2012

BACKGROUND.

Adrenocortical carcinoma (ACC) is a relatively rare but aggressive malignancy with limited therapeutic options. Previous genome‐wide expression studies have demonstrated the overexpression of interleukin‐13 receptor alpha2 (IL13Rα2) in some human malignancies.

METHODS.

The authors evaluated IL13Rα2 mRNA and protein expression in 21 normal samples, 78 benign samples, 10 primary malignant samples, and 25 metastatic/recurrent samples and performed functional analyses with IL13 ligand and IL13 Rα2 knockdown in vitro. The sensitivity of 2 ACC cell lines (NCI‐H295R [high IL13Rα2 expression] and SW13 [low IL13Rα2 expression]) to a highly specific IL‐13 conjugated with Pseudomonas exotoxin (IL‐13‐PE) also was evaluated in both in vitro and in vivo models.

RESULTS.

IL13Rα2 was overexpressed in malignant tumors compared with benign and normal samples (15‐fold higher; P < .05). Immunohistochemistry also confirmed higher protein expression in malignant and benign tumors than in normal adrenocortical tissues (P < .05). The half‐maximal inhibitory concentration for IL‐13‐PE was 1.3 ng/mL in the NCI‐H295R cell line and 1000 ng/mL in the SW13 cell line. Mice that received intratumoral or intraperitoneal IL‐13‐PE injection had a significant reduction in tumor size and increased tumor necrosis compared with control groups (P < .05) and also had prolonged survival (P < .05). IL13Rα2 protein expression increased in cells that were treated with IL‐13 ligand along with cell invasion (P < .05). Direct IL13Rα2 knockdown decreased cellular proliferation and invasion (P < .05).

CONCLUSIONS.

The current results indicated that IL13Rα2 is overexpressed in ACC and regulates cell invasion and proliferation. IL13Rα2 is a novel therapeutic target for the treatment of human ACC. Cancer 2012. © 2012 American Cancer Society.
Hilbert‐order based spatial cloaking algorithm in road network
Authors: Kim Yong‐Ki , Hossain Amina , Hossain Al‐Amin , Chang Jae‐Woo
Published: May 2012

Location‐based services (LBSs) are currently some of the fastest growing information technology industries. User privacy in LBSs has attracted great interest in the research community. However, the proliferation of position identifying devices has become an increasing privacy threat for users in LBSs. It is very difficult to avoid the privacy threat of a user in processing his/her request because the user has to submit his/her exact location with a query to the LBS. To protect privacy in road networks, the existing method employs an X‐Star framework to hide the query issuer and provide protection from attack resilience. However, it incurs low anonymization success rate and high computation cost. To solve the problems, we propose a Hilbert‐order‐based star network expansion cloaking algorithm (H‐Star). Our H‐Star guarantees k‐anonymity under the strict reciprocity condition and increases anonymization success rate by reducing computation overhead. We also propose k‐nearest neighbor and range query processing algorithms based on the anonymized region. Through comprehensive experimental analysis, we show the effectiveness of our algorithms in the field of spatial cloaking.Copyright © 2012 John Wiley & Sons, Ltd.