bluuebunny/crossref_metadata_2025_split huggingface dataset:
MIXING SEQUENCE IN NATURAL RUBBER CONTAINING ORGANOCLAY AND NANO–CALCIUM CARBONATE TERNARY HYBRID NANOCOMPOSITES
Authors: Ghari Hedayatollah Sadeghi , Arani Azam Jalali , Shakouri Zahra 
Published: May 2013

ABSTRACTRubber nanocomposites containing one type of nanofiller are common and are widely established in the research field. In this study, natural rubber (NR) based ternary nanocomposites containing both calcium carbonate and organoclay have been characterized on the basis of morphology, cure characteristics, and physico-mechanical behavior. Natural rubber nanocomposite samples containing modified silicate (Cloisite 15A) and also nano-carbonate calcium were prepared using a laboratory internal mixer. The effect of the mixing sequence on the morphology and mechanical properties of the samples was investigated. Based on results of morphology and mechanical properties, the dual fillers phase nanocomposites (hybrid nanocomposite) perform better in comparison with single filler phase nanocomposites. The reinforcing capability of nano-CaCO3 and organoclay in NR was characterized by means of cure rheometry, morphology, and mechanical properties. NR/single filler phase and two filler phase nanocomposites were prepared by simple melt mixing method. Concentration of nano-CaCO3 and organoclay in NR was 10 and 5 parts per one hundred parts of rubber by weight, respectively. The microstructure and homogeneity of the compounds was confirmed by studying the dispersion of nanoparticles in NR via X-ray diffraction and field emission scanning electron microscopy. A more pronounced effect was achieved by using dual filler based nanocomposites as compared with single filler phase nanocomposites. The obtained results reveal that hybrid nanocomposites have more adequate morphology, rheometery, and mechanical behaviors as well as swelling resistance. The effect of mixing sequence of fillers has been studied in detail. Simultaneous addition of the two nanofillers to the NR compound would lead to better nanocomposite properties compared with other mixing sequences. Also, the results show that the mixing sequence of these nanofillers in NR has little effect on the performance of the nanocomposite.
OPTIMIZATION OF RUBBER FORMULATION FOR SILICA-REINFORCED NATURAL RUBBER COMPOUNDS
Authors: Kaewsakul W. , Sahakaro K. , Dierkes W. K. , Noordermeer J. W. M. 
Published: May 2013

ABSTRACT
The rubber formulation plays a significant role in the properties of NR compounds filled with silica. In this work, the influences of various silicas, silane coupling agents, and diphenylguanidine (DPG) on the properties of compounds and vulcanizates—that is, cure characteristics, Mooney viscosity, flocculation kinetics, bound rubber content, Payne effect, tan δ at 60°C, tensile properties, and tear properties—are investigated. The results demonstrate that compound viscosity and curing behavior, as well as vulcanizate properties of the silica-filled NR, are much improved by incorporating silane coupling agents. Bis-triethoxysilylpropyltetrasulfide clearly gives better overall properties than the disulfide-based silane bis-triethoxysilylpropyldisulfide, except for scorch safety. DPG acts as a synergist to sulfenamide primary accelerators, as well as activator for the silanization reaction. Highly dispersible (HD) silicas can significantly enhance the degree of dispersion and so lead to higher filler–rubber interaction. As a consequence, the HD silicas provide better dynamic and mechanical properties for filled NR vulcanizates compared with conventional counterparts. The optimal quantities of both silane coupling agent and DPG required in the formulation are correlated to the cetyl trimethylammonium bromide specific surface area of the silicas. Furthermore, the results reveal that the silica structure as characterized by the dibutylphthalate adsorption also strongly influences the reinforcing efficiency.
SYNERGISTIC REINFORCEMENT OF ORGANOCLAY AND DOUBLE NETWORKING IN NATURAL RUBBER
Authors: Ghari Hedayatollah Sadeghi , Shakouri Zahra 
Published: May 2013

ABSTRACT
Research was undertaken on natural rubber (NR) nanocomposites with organoclays. A double-network (DN) structure is formed when a partially cross-linked elastomer is further cross-linked during a state of strain. Two methods were used in the preparation of NR/organoclay nanocomposites: the ordinary method (single-network NR nanocomposite) and double-networked NR (DN-NR) nanocomposites. The single-networked NR nanocomposites were used for comparison. The effects of organoclay (5 phr) with a different extension ratio on curing characteristics, mechanical properties, hardness, swelling behavior, and morphology of single- and double-networked NR nanocomposites were studied. The results showed that double-networked NR nanocomposites exhibited higher physical and mechanical properties. The tensile strength of DN-NR nanocomposites increased up to 33 MPa (more than four times greater than that of pure NR) and then decreased with an increasing extension ratio. Modulus and hardness continuously increased with an increased extension ratio. The microstructure of the NR/organoclay systems was studied by X-ray diffraction and field emission scanning electron microscopy. The effects of different extension ratios on the dispersion of organoclay layers in the nanocomposites were investigated. Generally, results showed that the optimized extension ratio in DN nanocomposites was equal (or about or around) to α= 2.
NATURAL RUBBER/CARBON NANOTUBE NANOCOMPOSITES PREPARED BY ULTRASONICALLY AIDED EXTRUSION
Authors: Choi Jaesun , Isayev Avraam I. 
Published: May 2013

ABSTRACTNatural rubber/multiwalled carbon nanotube (MWCNT) nanocomposites at loadings from 2 to 25 phr were prepared by ultrasonically aided extrusion at ultrasonic amplitudes up to 7.5 μm. Die pressure significantly decreased with an increase of ultrasonic amplitude, especially at higher loadings. Power consumption increased with ultrasonic amplitude and was almost insensitive to loadings until an amplitude of 5.0 μm. However, lower values of power consumption were observed at an amplitude of 7.5 μm for loadings of 10 and 15 phr. At these loadings, complex viscosity, storage, and loss moduli of compounds and vulcanizates were unaffected by ultrasonic treatment, whereas at other loadings, these properties were reduced with ultrasonic amplitude, indicating chain scission. Bound rubber in compounds decreased with treatment. The induction time during vulcanization was unaffected by ultrasonic treatment but decreased with loading, with the largest decrease observed at the lowest loading. The maximum torque in curing, cross-link density, and gel fraction of vulcanizates at loadings of 2, 3.5, 5, 7.5, and 25 phr decreased with ultrasonic amplitude, with the largest decrease observed at loading of 25 phr at an amplitude of 7.5 μm. The modulus at 100% and 300% and tensile strength of vulcanizates at loadings up to 15 phr were unaffected by the ultrasonic treatment, but these properties significantly decreased at a loading of 25 phr at an amplitude of 7.5 μm. Atomic force microscope studies of vulcanizates at a loading of 3.5 phr showed a deagglomeration at an amplitude of 7.5 μm, although dispersion analysis from an optical microscope at loadings of 3.5 and 7.5 phr did not show an improvement of dispersion by ultrasonic treatment. Optical microscope and AFM studies of vulcanizates at a loading of 25 phr indicated that ultrasonic treatment at an amplitude of 7.5 μm significantly improved dispersion of MWCNT. Such a behavior led to a strong Payne effect and an increase in hardness of vulcanizates.
Feedback systems with communications: integrated study of signal estimation, sampling, quantization, and feedback robustness
Authors: Wang Le Yi , George Yin G. , Li Chanying , Zheng Wei Xing 
Published: May 2013

SUMMARYFeedback systems with communication channels encounter unique challenges. Communication channels mandate signal sampling and quantization, and introduce errors, data losses, and delays. Consequently, transmitted signals must be estimated. The signal estimation introduces a dynamic system that interacts with communication channels and affects the stability and performance of the feedback system. This paper studies interactions among communications, sampling, quantization, signal estimation, and feedback, in terms of fundamental stability and performance limitations. Typical empirical‐measure‐based algorithms are used for signal estimation under quantized observations. When the sampling interval and signal estimation step size are coordinated, the ODE approach for stochastic approximations provides a suitable platform for an integrated system analysis for signal estimation, sampling and quantization, and feedback robustness. Feedback design for enhancing robustness against communication uncertainty and signal estimation dynamics is studied under the new notion of stability margin under signal averaging. Fundamental limitations on noise attenuation in such an integrated system are derived. Copyright © 2013 John Wiley & Sons, Ltd.
A Mitochondria‐Targeting Gold–Peptide Nanoassembly for Enhanced Cancer‐Cell Killing
Authors: Ma Xiaochuan , Wang Xiaobo , Zhou Ming , Fei Hao 
Published: May 2013

AbstractDesign and construction of multifunctional nanoparticles for effective delivery and therapeutic application remains a challenging task. It is desirable that nanoparticles can overcome multiple biological barriers and reach specific cellular locations to achieve maximum therapeutic effects. This aim often requires the fine tuning of nanoparticles' chemical and physical properties, as well as better understanding of their interaction with live cells. A peptide‐modified gold–nanoparticle platform is designed, which consists of a 20‐nm gold core stabilized with a layer of biotinylated CALNN‐based peptides and a further layer of tetrameric streptavidins for functionalization with biotinylated molecules. The nanoassembly undergoes an efficient dynamin‐dependent and caveolae‐mediated endocytosis pathway, and displays highly specific localization to mitochondria, organelles of great therapeutic importance. When functionalized with a cytotoxic peptide (KLA: (KLAKLAK)2), the KLA‐anchored nanoassembly exhibits dramatically enhanced anticancer activity, thousands of times stronger than that of the free KLA peptide, likely because of its improved cell entry efficiency, mitochondria‐specific delivery, and the polyvalent effect of the nanoassembly. The study opens up the possibility of developing mitochondria‐targeted nanomedicines.
Delineation of a region responsible for panhypopituitarism in 20p11.2
Authors: Dayem‐Quere Manal , Giuliano Fabienne , Wagner‐Mahler Kathy , Massol Christophe , Crouzet‐Ozenda Letizia , Lambert Jean‐Claude , Karmous‐Benailly Houda 
Published: May 2013

AbstractWe report on the case of a young woman with a de novo 20p11.21p11.23 deletion, discovered by array‐CGH. She has behavioral troubles with autistic traits, intellectual disability, panhypopituitarism, severe hypoglycemia, epilepsy, and scoliosis. The majority of the reported 20p deletions are located on the 20p12 region, covering the JAG1 gene responsible for the Alagille syndrome. More proximal deletions are even rarer, with very few cases described in the literature to date. The deletion carried by our patient is, to our knowledge, the smallest described de novo proximal 20p11.2 deletion. It was first discovered by 0.5 Mb BAC array‐CGH, further delineated using an oligonucleotide array, and finally confirmed by fluorescence in situ hybridization. The deletion is 4.22 Mb in size, with the exact location on chr20: 19.810.034–24.031.344 (Feb. 2009, GRCh37/hg19). In light of the other reported cases that display genomic and phenotypic overlap with our patient, we discuss the phenotype of our patient, in order to further delineate the 20p proximal deletion phenotype. We propose a minimal critical region responsible for panhypopituitarism with global developmental delay, intellectual disability, scoliosis and facial dysmorphism. Moreover, considering the deleted genes, we highlight the impact of the deletion of this minimal critical region on the Shh signaling pathway. © 2013 Wiley Periodicals, Inc.
Hybrid Model Predictive Control of Exhaust Recompression Hcci
Authors: Widd Anders , Liao Hsien‐Hsin , Gerdes J. Christian , Tunestål Per , Johansson Rolf 
Published: May 2013

AbstractHomogeneous charge compression ignition (HCCI) holds promise for reduced emissions and increased efficiency compared to conventional internal combustion engines. As HCCI lacks direct actuation over the combustion phasing, much work has been devoted to designing controllers capable of set‐point tracking and disturbance rejection. This paper presents results on model predictive control (MPC) of the combustion phasing in an HCCI engine based on a hybrid model formulation composed of several linearizations of a physics‐based nonlinear model. The explicit representation of the MPC was implemented experimentally and the performance during set point changes was compared to that of a switched state feedback controller. The hybrid MPC produced smoother transients without overshoot when the set point change traversed several linearizations.
Functional expression of amyloidogenic human stefins A and B in Pichia pastoris using codon optimization
Authors: Nakamura Kosuke , Maeda Yuki , Morimoto Kensuke , Katayama Shigeru , Kondo Kazunari , Nakamura Soichiro 
Published: May 2013

AbstractComplementary DNAs encoding human stefins A (HSA) and B (HSB) were synthesized using Pichia‐preferred codons by overlap extension PCR. The full‐length genes were ligated downstream of the glyceraldehyde‐3‐phosphate dehydrogenase promoter in the Pichia expression vector pGAPZαC and successfully expressed in Pichia pastoris strain X‐33. Functional recombinant HSA and HSB proteins were purified from culture medium at yields of 121.3 ± 13.5 (n = 3) and 95.4 ± 4.1 (n = 3) mg/L, respectively. Using this expression strategy, we demonstrated that high levels of bioactive recombinant HSA and HSB can be produced by fermentation in P. pastoris.
A probe to study the toxic interaction of tartrazine with bovine hemoglobin at the molecular level
Authors: Li Yating , Wei Haoran , Liu Rutao 
Published: May 2013

ABSTRACTTartrazine is an artificial azo dye commonly used in food products, but tartrazine in the environment is potentially harmful. The toxic interaction between tartrazine and bovine hemoglobin (BHb) was investigated using fluorescence, synchronous fluorescence, UV–vis absorption, circular dichroism (CD) and molecular modeling techniques under simulated physiological conditions. The fluorescence data showed that tartrazine can bind with BHb to form a complex. The binding process was a spontaneous molecular interaction, in which van der Waals' forces and hydrogen bonds played major roles. Molecular docking results showed that the hydrogen bonds exist between the oxygen atoms at position 31 of tartrazine and the nitrogen atom NZ7 on Lys99, and also between the oxygen atoms at position 15 of tartrazine and the nitrogen atom NZ7 on Lys104, Lys105. The results of UV–vis and CD spectra revealed that tartrazine led to conformational changes in BHb, including loosening of the skeleton structure and decreasing α helix in the secondary structure. The synchronous fluorescence experiment revealed that tartrazine binds into the hemoglobin central cavity, and this was verified using a molecular modeling study. Copyright © 2013 John Wiley & Sons, Ltd.
Strategies for Using Microreactors and Flow Chemistry: Drivers and Tools
Authors: Kirschneck D. 
Published: May 2013

AbstractAn innovative concept for the characterization of situations or problems (drivers) where the application of continuous flow processing, microreactor and/or other intensification technologies lead to the desired solutions is presented. An overview of techniques and equipment (tools) currently available for developing intensified processes is given as well as some examples of how they can be implemented in the engineering of chemical plants in kilo‐lab, pilot‐, and full‐size manufacturing scale. These drivers and tools are described and depicted by easy‐to‐understand icons, and strategies for the development of continuous processes are explained. Short summaries of three different case studies demonstrate the economic advantages and potentials of intensified flow processing in manufacturing scale. Finally, the current approach to avoid inflexibility of systems operated in continuous mode is reported and how pilot and manufacturing plants can be realized with a special focus on modularity and multi‐purpose functionality.
Application of Ultrasound in a Micro Heat Exchanger for Crystallization of Solid Lipid Nanoparticles
Authors: Schoenitz M. , Joseph S. , Bunjes H. , Scholl S. 
Published: May 2013

AbstractThe application of ultrasound during the batch‐wise as well as continuous crystallization of lipid nanoparticles is reported. For the latter, a micro heat exchanger is modified, allowing the inline application of ultrasound to promote the α‐to‐β transformation of the lipid nanoparticles. Ultrasonication during batch crystallization is carried out in an ultrasonic bath. While for batch processing the application of ultrasound leads to an increase of the fraction of stable β‐polymorph according to differential scanning calorimetry measurements, no significant increase is found for continuous operation. This is a result of one or both of the following effects: The residence time in the continuous micro heat exchanger is approximately 1 s and thus possibly too short for significant influences on the polymorphism or crystallization. Additionally, the ultrasound is induced indirectly to the product side and thus reduced.
Combining Ozonation and Ceramic Membrane Filtration for Tertiary Treatment
Authors: Stüber Johan , Miehe Ulf , Stein Robert , Köhler Mirco , Lesjean Boris 
Published: May 2013

AbstractA pilot plant with a full scale monolithic ceramic membrane was operated at Ruhleben wastewater treatment plant (WWTP), Berlin Germany, for more than 12 months. Filtration performance according to the applied pre‐treatment (dose of ozone and coagulant) were investigated. Trial runs with and without ozone, varying the operational parameters such as flux, coagulant dosage, and filtration time were conducted in order to identify the benefits of pre‐ozonation. The reduction of the total fouling rate by ∼70 % when applying a specific ozone dose between 1.0 and 1.4 mg mgDOC–1 highlights the potential of ozonation as pre‐treatment step. Using LC‐OCD measurements, the effect of ozone on the biopolymer concentration and the DOC fraction was demonstrated.
Mutation‐specific antibody detects mutant BRAFV600E protein expression in human colon carcinomas
Authors: Sinicrope Frank A. , Smyrk Thomas C. , Tougeron David , Thibodeau Stephen N. , Singh Shalini , Muranyi Andrea , Shanmugam Kandavel , Grogan Thomas M. , Alberts Steven R. , Shi Qian 
Published: May 2013

BACKGROUNDA point mutation (V600E) in the BRAF oncogene is a prognostic biomarker and may predict for nonresponse to anti‐EGFR antibody therapy in patients with colorectal carcinoma. BRAFV600E mutations are frequently detected in tumors with microsatellite instability and indicate a sporadic origin. We used a mutation‐specific antibody to examine mutant BRAFV600E protein expression and its concordance with BRAFV600E mutation data.METHODSPrimary stage III colon carcinomas were analyzed for BRAFV600E mutations in exon 15, and 50 BRAFV600E mutation carriers and 25 wild‐type tumors were selected for analysis of BRAF proteins by immunohistochemistry (IHC). IHC was performed in archival tissue specimens using a pan‐BRAF antibody and a mutation‐specific antibody against BRAFV600E proteins. Staining was scored by 2 pathologists who were blinded to clinical and mutation data.RESULTSUsing a pan‐BRAF antibody, total BRAF protein expression was observed in the tumor cell cytoplasm in 74 of 75 colon carcinomas. A mutation‐specific antibody identified diffuse cytoplasmic staining of mutant BRAFV600E proteins in 49 of 74 cancers. Analysis using a polymerase chain reaction‐based assay revealed that all 49 of these cancers carried BRAFV600E mutations. In contrast, BRAFV600E staining was absent in all 25 tumors that carried wild‐type copies of BRAF.CONCLUSIONSA BRAF mutation‐specific (V600E) antibody detected tumors with BRAFV600E mutations and exhibited complete concordance with a DNA‐based method. These results support the use of IHC as a simplified strategy to screen colorectal cancers for BRAFV600E mutations in clinical practice. Cancer 2013;119:2765–2770. © 2013 American Cancer Society.
Effects of transitioning from conventional methods to liquid‐based methods on unsatisfactory Papanicolaou tests
Authors: Owens Christopher L. , Peterson Dan , Kamineni Aruna , Buist Diana S. M. , Weinmann Sheila , Ross Tyler R. , Williams Andrew E. , Stark Azadeh , Adams Kenneth F. , Field Terry S. 
Published: May 2013

BACKGROUNDPapanicolaou (Pap) testing has transitioned from conventional preparations (CPs) to liquid‐based preparations (LBPs) because of the perceived superiority of LBPs. Many studies conclude that LBPs reduce unsatisfactory Pap tests; however, some believe that the evidence substantiating this claim is weak. The authors studied the effect of the transition from CPs to LBPs on the proportion of unsatisfactory Pap tests in 4 health care systems in the United States participating in the National Institutes of Health‐funded Screening Effectiveness and Research in Community‐Based Healthcare (SEARCH) project.METHODSThe study cohort consisted of 548,174 women ages 21 to 65 years who had 1443,725 total Pap tests between 2000 and 2010. Segmented regression analysis was used to estimate the effect of adopting LBPs on the proportion of unsatisfactory Pap tests after adjusting for age.RESULTSThree sites that implemented SurePath LBP experienced significant reductions in unsatisfactory Pap tests (estimated effect: site 1, −2.46%; 95% confidence interval [CI], −1.47%, −3.45%; site 2, −1.78%; 95% CI, −1.54%, −2.02%; site 3, −8.25%; 95% CI, −7.33%, −9.17%). The fourth site that implemented ThinPrep LBP did not experience a reduction in unsatisfactory Pap tests. The relative risk of an unsatisfactory Pap test in women aged ≥50 years increased after the transition to LBPs (SurePath: relative risk, 2.1; 95% CI, 1.9‐2.2; ThinPrep: relative risk, 1.7; 95% CI, 1.5‐2.0).CONCLUSIONSThe observed changes in the proportion of unsatisfactory Pap tests varied across the participating sites and depended on the type of LBP technology, the age of women, and the rates before the implementation of this technology. Cancer (Cancer Cytopathol) 2013;121:568–575. © 2013 American Cancer Society.