bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response Surface Analysis and Nonlinear Optimization Algorithm for Maximization of Clinical Drug Performance: Application to Extended‐Release and Long‐Acting Injectable Paliperidone
Authors: Gomeni Roberto , Bressolle‐Gomeni Françoise , Fava Maurizio 
Published: February 2016

AbstractModel‐based approach is recognized as a tool to make drug development more productive and to better support regulatory and therapeutic decisions. The objective of this study was to develop a novel model‐based methodology based on the response surface analysis and a nonlinear optimizer algorithm to maximize the clinical performances of drug treatments. The treatment response was described using a drug‐disease model accounting for multiple components such as the dosage regimen, the pharmacokinetic characteristics of a drug (including the mechanism and the rate of drug delivery), and the exposure‐response relationship. Then, the clinical benefit of a treatment was defined as a function of the diseases and the clinical endpoints and was estimated as a function of the target pharmacodynamic endpoints used to evaluate the treatment effect. A case study is presented to illustrate how the treatment performances of paliperidone extended release (ER) and paliperidone long‐acting injectable (LAI) can be improved. A convolution‐based approach was used to characterize the pharmacokinetics of ER and LAI paliperidone. The drug delivery properties and the dosage regimen maximizing the clinical benefit (defined as the target level of D2 receptor occupancy) were estimated using a nonlinear optimizer. The results of the analysis indicated that a substantial improvement in clinical benefit (from 15% to 27% for the optimization of the in vivo release and from ∼30% to ∼70% for the optimization of dosage regimen) was obtained when optimal strategies were deployed either for optimizing the in vivo drug delivery properties of ER formulations or for optimizing the dosage regimen of LAI formulations.
A Clinical Study Evaluating the Effects of Fluvastatin on Serum Osteoprotegerin Levels in Rheumatoid Arthritis Patients
Authors: Hegazy Sahar Kamal , El‐Ghany El‐Sayed Salwa El‐Morsy Abd , El‐Hefnawy Marwa El‐Saeed 
Published: February 2016

AbstractOsteoprotegerin (OPG), a member of the tumor necrosis factor receptor family, has been identified as a critical regulator of bone resorption. Considering the possible role of OPG in rheumatoid arthritis (RA) and in the osteoclastogenesis suppression effects of statins, the present study aims to investigate the effects of fluvastatin on serum levels OPG and disease activity score (DAS) in patients with RA. Forty patients with RA were randomized in a placebo‐controlled trial to receive 40 mg fluvastatin or placebo as an adjunct to existing disease‐modifying antirheumatic drug (DMARD) therapy (methotrexate, leflunomide, hydroxychloroquine). Patients were followed up over 12 weeks. OPG and disease activity variables were measured at baseline and after 12 weeks of treatment. After 12 weeks, the OPG level was significantly increased in the fluvastatin group compared to the placebo group. DAS‐28 was significantly decreased in the fluvastatin group compared to the placebo group. C‐reactive protein (CRP), morning stiffness, swollen joint count (SJC), and tender joint count (TJC) were significantly decreased in the fluvastatin group compared to the placebo group; however, erythrocyte sedimentation rate (ESR), modified health assessment questionnaire (MHAQ), and visual analogue screen (VAS) were not changed significantly. In conclusion, fluvastatin administration could increase the OPG levels and improve disease activity variables in patients with RA. Therefore, fluvastatin may serve a potential benefit in the treatment of RA patients.
The Maximum Number of Complete Subgraphs of Fixed Size in a Graph with Given Maximum Degree
Authors: Cutler Jonathan , Radcliffe A. J. 
Published: February 2016

AbstractIn this article, we make progress on a question related to one of Galvin that has attracted substantial attention recently. The question is that of determining among all graphs G with n vertices and , which has the most complete subgraphs of size t, for . The conjectured extremal graph is , where with . Gan et al. (Combin Probab Comput 24(3) (2015), 521–527) proved the conjecture when , and also reduced the general conjecture to the case . We prove the conjecture for and also establish a weaker form of the conjecture for all r.
Association of the apparent diffusion coefficient with maturity in adolescent sacroiliac joints
Authors: Bray Timothy J.P. , Vendhan Kanimozhi , Roberts James , Atkinson David , Punwani Shonit , Sen Debajit , Ioannou Yiannis , Hall‐Craggs Margaret A. 
Published: February 2016

PurposeTo determine the extent to which apparent diffusion coefficient (ADC) values vary with skeletal maturity in adolescent joints.Materials and MethodsA retrospective study was performed with Institutional Review Board (IRB) approval. We used a picture archiving and communication system (PACS) search to identify and recruit all adolescents who had undergone 1.5T magnetic resonance imaging (MRI) of the sacroiliac joints (SIJs) between January 2010 and June 2015, and had no evidence of sacroiliitis and normal inflammatory markers. In all, 55 individuals were assessed. For each patient, coronal and sagittal images of the sacrum were visually analyzed to determine sacral maturity. Patients were divided into three groups depending on the degree of fusion of the sacral segmental apophyses: “Fused,” “Partial,” and “Unfused.” For each group, SIJ ADC was measured using a linear region‐of‐interest technique.ResultsMean ADC values were 690 × 10−6 mm2/s in the fused group, 720 × 10−6 mm2/s in the partial group, and 842 × 10−6 mm2/s in the unfused group. ADC values were significantly higher in the unfused group than in the fused group (P = 0.046). ADC values were also higher in unfused subjects than partially fused subjects (P = 0.074).ConclusionJoint ADC values are higher in skeletally immature (unfused) patients than in skeletally more mature (fused) patients. ADC values measured in the unfused group overlap with those previously reported in sacroiliitis. These results suggest that ADC measurements in adolescent joints must be interpreted in light of joint maturity. Joint immaturity may lead to misdiagnosis of sacroiliitis, since immature juxta‐articular bone may appear similar to inflammation. J. Magn. Reson. Imaging 2016. J. Magn. Reson. Imaging 2016;44:556–564.
A Tailor‐Made Synthetic Polymer for Cell Encapsulation: Design Rationale, Synthesis, Chemical–Physics and Biological Characterizations
Authors: Gerges Irini , Tamplenizza Margherita , Rossi Eleonora , Tocchio Alessandro , Martello Federico , Recordati Camilla , Kumar Deepak , Forsyth Nicholas R. , Liu Yang , Lenardi Cristina 
Published: February 2016

This study presents a custom‐made in situ gelling polymeric precursor for cell encapsulation. Composed of poly((2‐hydroxyethyl)methacrylate‐co‐(3‐aminopropyl)methacrylamide) (P(HEMA‐co‐APM) mother backbone and RGD‐mimicking poly(amidoamine) (PAA) moiteis, the comb‐like structured polymeric precursor is tailored to gather the advantages of the two families of synthetic polymers, i.e., the good mechanical integrity of PHEMA‐based polymers and the biocompatibility and biodegradability of PAAs. The role of P(HEMA‐co‐APM) in the regulation of the chemico‐physical properties of P(HEMA‐co‐APM)/PAA hydrogels is thoroughly investigated. On the basis of obtained results, namely the capability of maintaining vital NIH3T3 cell line in vitro for 2 d in a 3D cell culture, the in vivo biocompatibility in murine model for 16 d, and the ability of finely tuning mechanical properties and degradation kinetics, it can be assessed that P(HEMA‐co‐APM)/PAAs offer a cost‐effective valid alternative to the so far studied natural polymer‐based systems for cell encapsulation.
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Polyaniline‐Wrapped ZnO Nanorod Composite Films on Diazonium‐Modified Flexible Plastic Substrates
Authors: Mekki Ahmed , Ait‐Touchente Zouhair , Samanta Soumen , Singh Ajay , Mahmoud Rachid , Chehimi Mohamed M. , Aswal Dinesh K. 
Published: February 2016

Vertically aligned core/shell‐like polyaniline‐wrapped ZnO nanorod composite films are prepared on diazonium‐modified biaxially oriented polyethylene terephthalate (BOPET) sheets, in two main steps. (i) The BOPET substrate is modified by grafting of 4‐aminobenzenoic groups from the in situ generated diazonium compound; (ii) ZnO nanorod/polyaniline composite film is grown on the substrates by wet chemical route followed by the preparation of polyaniline (PANI) by in situ chemical oxidative polymerization of aniline on the immobilized ZnO nanorods. Scanning electron microscopy images reveal the vertical growth and homogeneous distribution of the ZnO nanorods and their nanocomposites on the diazonium modified substrates. In contrast, the ZnO and PANI‐coated ZnO nanorods are randomly distributed on pristine BOPET. X‐ray photoelectron spectra permit to characterize the chemical nature of the aryl and the nano­composite adlayers. X‐ray diffraction analysis results indicate that ZnO nanorods retain their wurtzite structure within the nanocomposite coating. Fourier‐transform infrared (FTIR) and Raman indicate the presence of interaction between ZnO nanorods and PANI chains. The ZnO/PANI‐coated diazonium‐modified BOPET sheets exhibit excellent mechanical flexibility with electroconductive characteristics even in the highly bent state. This work highlights the efficiency of the interfacial chemistry of aryl diazonium salts in the preparation of nanocomposite films with outstanding morphology, adhesion, and physical properties even under mechanical stress.image
Synergistic Effect of Functionalized Carbon Nanotubes and Micron‐Sized Rubber Particles on the Mechanical Properties of Epoxy Resin
Authors: Zewde Berhanu , Pitliya Praveen , Karim Alamgir , Raghavan Dharmaraj 
Published: February 2016

In this study, the synergistic effect of functionalized carbon nanotubes (fCNT) and micron‐sized rubber particles in improving the thermomechanical properties of epoxy resin is demonstrated. fCNT is mixed with carboxyl‐terminated butadiene acrylonitrile toughened epoxy (CTBNTE) by ultrasonication followed by the addition of curing agent and mixing with planetary shear mixer. A significant improvement is noticed in fracture toughness (≈ 200%) and thermal stability (≈ 12 °C) of fCNT‐filled CTBNTE system but only a marginal improvement in fracture toughness and thermal stability of pristine CNT‐filled CTBNTE relative to epoxy. Dispersion of fCNT is better than pristine CNT in the epoxy matrix. Scanning electron microscope (SEM) images of fractured surface of fCNT‐filled CTBNTE reveal plastic deformation zone, stress whitening, and overall rougher surface compared to pristine CNT‐filled CTBNTE. The findings of our work show promise for use of fCNT in conjunction with a rubber toughener as filler for improving the properties of epoxy resin for advanced structural applications.image
Shear Viscosity of Poly (Acrylamide/Acrylic Acid) Solutions
Authors: Riahinezhad Marzieh , McManus Neil , Penlidis Alexander 
Published: February 2016

SummaryAcrylamide (AAm)/Acrylic acid (AAc) copolymers are being used in a wide spectrum of applications, from which enhanced oil recovery (EOR) is the target application in this research study. The shear viscosity of the copolymer solution is extremely important in determining the performance properties of AAm/AAc copolymers. A series of copolymers with selected properties were prepared to study the effect of polymer concentration, copolymer composition, and salinity on the shear viscosity of the copolymer solutions. The results revealed the considerable effect of solution concentration and salinity on shear viscosity. Moreover, the behavior of the copolymer composition showed a maximum with respect to shear viscosity.
Conductive Elastomer Composites Based on Inherent and Extrinsic Conductive Polymers
Authors: Rosas‐Aburto Alberto , Roquero‐Tejeda Pedro , Vivaldo‐Lima Eduardo , Pérez‐Salinas Patricia , Phifer Daniel W. , Vázquez R. Javier Revilla 
Published: February 2016

SummaryPrinted Electronics is the designation given to a set of new technological routes for the manufacture of electronic devices which are light, discrete, flexible, and capable of folding. These devices require power sources that share these properties. This paper is focused on how to obtain electrically conductive elastomer composites. These elastomeric composite materials are obtained by mechanical mixing of electronic and ionic conductive polymers with commercial grade styrene‐butadiene rubbers (SBS). The produced materials had good capacitance, thus performing well as rechargeable batteries. These materials were characterized by scanning electron microscopy (SEM) and electrical conductivity measurements to quantify the abundance and distribution of conductive polymers within the rubbery matrix. Our generated experimental results were used to test the predictive power of two mathematical equations based on Hashin–Shtrikman models and composites theory, respectively. Electrical conductivity vs voltage profiles for these conductive elastomer composites were adequately predicted by these models.
Influence of Activation Conditions on the Gas Phase Polymerisation of Propylene
Authors: Cancelas Aarón J. , Monteil Vincent , McKenna Timothy F. L. 
Published: February 2016

SummaryThe impact of injection conditions of a supported Ziegler Natta catalyst on the rate of polymerization of propylene in a gas phase process is investigated. It is observed that the instantaneous rate of propylene polymerization is higher if the catalyst is injected wetted with a hydrocarbon before being charged to the reactor. This is attributed to the effect of the hydrocarbon in decreasing local particle overheating for the critical initial instants of polymerization, due to lower diffusion of the monomer to the active sites and to absorption of the heat of vaporization. An enhancement of the observed initial polymerization rate is also observed with prepolymerization.
Controlled Release of Vitamin B‐12 Using Hydrogels Synthesized by Free Radical and RAFT Copolymerization in scCO2
Authors: Pérez‐Salinas Patricia , Rosas‐Aburto Alberto , Antonio‐Hernández Carlos Hipólito , Jaramillo‐Soto Gabriel , Vivaldo‐Lima Eduardo , Licea‐Claverie Ángel , Castro‐Ceseña Ana Bertha , Vázquez‐Torres Humberto 
Published: February 2016

SummaryResearch in polymer network synthesis is mostly focused on materials with absorbent or controlled‐release properties. They are important in healthcare applications. Free radical copolymerization is the main route to obtain gels, using monomers and crosslinking agents, but the materials produced by this route are highly heterogeneous. These heterogeneities reduce the efficiency of chemical compounds used in controlled‐release applications. Our research is focused on creating new routes of polymer synthesis to reduce these heterogeneities. In this article, we compare gels synthesized by conventional free radical and by reversible addition‐fragmentation chain transfer (RAFT) copolymerization of acrylic monomers in supercritical carbon dioxide. These gels are evaluated for controlled drug delivery applications with vitamin B12. The materials were characterized by scanning electron microscopy (SEM), nitrogen adsorption (BET), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). These characterization techniques allowed us to determine the morphology and texture of each hydrogel and to explain how vitamin release performance is affected by these characteristics of the hydrogel.
Multiscale Modeling of Expanding Polyurethane Foams via Computational Fluid Dynamics and Population Balance Equation
Authors: Karimi Mohsen , Droghetti Hermes , Marchisio Daniele L. 
Published: February 2016

SummaryThis study is aimed to formulate a numerical modeling recipe for polyurethane foams. The model is capable of simulating the foam principal characteristics during mold filling. The model is formulated upon coupling of Computational Fluid Dynamics (CFD) and Population Balance Equation (PBE) to predict and simulate the evolution of foam features including apparent density and viscosity, bubble (or cell) size distribution (BSD) during the polymerization, as well as its kinetics. The solution of PBE inside the CFD code is performed with Quadrature Method of Moments (QMOM). The foam, constituted by a liquid polymer and gas bubbles, is simulated as a pseudo‐single‐phase system, while the interface between the foam and the surrounding air is tracked by a Volume‐of‐Fluid (VOF) solver within the open‐source CFD code OpenFOAM. The modeling is applied for a simple foaming experiment and attention is paid to the effect of the rheological model on the predictions.
Fouling in the High Pressure LDPE Process: Experimental and Computational Investigation Approach
Authors: Fries Sebastian , Castañeda‐Zúñiga Diego Mauricio , Duchateau Jan , Neuteboom Peter , Porras Carolina Toloza , Busch Markus 
Published: February 2016

SummaryA combined experimental and computational approach is presented in order to study reactor fouling in high pressure LDPE tubular reactors. Indications are found that fouling is a process driven by low polymer diffusion speeds and higher friction in the region close to the reactor wall. These findings can explain the formation of polymer rich layers on the reactor wall which are responsible for the reduction of heat transfer and typical tailing observed in molecular weight distributions of LDPE.
Coupled Deterministic and Stochastic Modeling of an Industrial Multi‐Zone LDPE Autoclave Reactor
Authors: Eckes David , Busch Markus 
Published: February 2016

SummarySimulation aided product design of LDPE often requires deep understanding of polymer architectures produced in the industrial polymerization. Therefore, a hybrid‐stochastic approach is further developed that allows for the good description of the typical polymeric microstructure produced in a multi‐zone autoclave reactor. The here presented kinetic network goes beyond the basic polymerization scheme and accounts for the propagation of terminal double bonds as well as the mechanical degradation of polymer molecules due to shear stress. By including these reactions a good agreement between experimental and predicted molecular weight distribution is achieved. Furthermore, the comparison of individual contraction factors from experimental data and contraction factors calculated by a 3‐D random walker result in a good agreement.
Production of Polyolefins by Metallocene Catalysts and Their Recycling by Pyrolysis
Authors: Kaminsky Walter 
Published: February 2016

SummaryPolyolefins are the main industrial used polymers as they are sustainable materials. They show a wide variety of properties, consist of only carbon and hydrogen atoms, can efficiently be produced from easy available monomers and can be recycled. Beside Ziegler‐Natta and Phillips catalysts, metallocenes and other transition metal complexes, activated by methylaluminoxane allow to tailor the structure, the tacticity, and the stereoregularity of polyolefins in a way which has not been reached before. Metallocene catalysts are able to copolymerize ethene or propene with different olefins, cyclic olefins, polar monomers as well as with macromers to form polymer short or long chain branched polymers with new properties. Polyolefin wastes can easily be recycled by extrusion moulding or by pyrolysis to gas and oil. While for extrusion moulding pure polymers have to be used the pyrolysis can take mixed and contaminated polyolefins. In a fluidized bed process, indirectly heated by fire tubes, different products are obtained in dependence of the pyrolysis temperature. By 500°C about 90 % aliphatic waxes are formed, by 700°C mainly olefins and aromatics. By addition of Lewis acids such as titanium or aluminum chlorides to the fluidized bed it is possible to decreasing the pyrolysis temperature by 100 °C.
Assessment of vitamin D levels in type 1 and type 2 diabetes patients: Results from metaanalysis
Authors: Shen Liang , Zhuang Qi‐Shuai , Ji Hong‐Fang 
Published: February 2016

ScopeAccumulating evidence indicates that vitamin D deficiency is prevalent in patients with type 1 (T1D) and type 2 diabetes (T2D). The present study aims to assess 25‐hydroxyvitamin D [25(OH)D] levels in T1D and T2D patients compared with controls through a metaanalysis.Methods and resultsWe searched databases for articles published until January 2015. A total of 12 studies covering 2003 patients and 1882 controls and 11 studies covering 2236 patients and 2438 controls were included to metaanalyze 25(OH)D levels in patients with T1D and T2D, respectively. Pooled data showed that T1D patients had lower levels of 25(OH)D than controls (summary standardized mean difference (SMD) –0.70, 95% confidence interval (CI) –1.02 to –0.37). Further age‐subgroup analysis found that 25(OH)D levels in T1D patients was also significantly lower than controls in subgroup aged ≤ 14 years (summary SMD –1.04, 95% CI –1.55 to –0.53), while the association is not statistically significant in the subgroup aged > 14 years. Similarly, T2D patients had lower 25(OH)D levels compared with controls (summary SMD –0.58, 95%CI –1.16 to –0.00).ConclusionAvailable data indicated that both T1D and T2D patients had lower levels of 25(OH)D than controls overall. The mechanistic underpinnings of this association warrant further elucidation.
Development of a symmetric echo planar imaging framework for clinical translation of rapid dynamic hyperpolarized 13C imaging
Authors: Gordon Jeremy W. , Vigneron Daniel B. , Larson Peder E.Z. 
Published: February 2016

PurposeTo develop symmetric echo planar imaging (EPI) and a reference scan framework for hyperpolarized 13C metabolic imaging.MethodsSymmetric, ramp‐sampled EPI with partial Fourier reconstruction was implemented on a 3T scanner. The framework for acquiring a reference scan on the 1H channel and applied to 13C data was described and validated in both phantoms and in vivo metabolism of [1‐13C]pyruvate.ResultsRamp‐sampled, symmetric EPI provided a substantial increase in the signal‐to‐noise ratio of the phantom experiments. The reference scan acquired on the 1H channel yielded 13C phantom images that varied in mean signal intensity <2%, compared with 13C images reconstructed with a reference scan directly measured on the 13C channel. The structural similarity index and dynamic time course from in vivo 13C data further support the application of a 1H reference scan to 13C data to mitigate Nyquist ghost artifacts.ConclusionRamp‐sampled, symmetric EPI with spectral‐spatial excitation of a single metabolite provides a fast, robust, and clinically efficacious approach to acquire hyperpolarized 13C dynamic molecular imaging data. The gains of this efficient sampling, combined with partial Fourier methods, enables large matrix sizes required for human studies. Magn Reson Med 77:826–832, 2017. © 2016 International Society for Magnetic Resonance in Medicine