bluuebunny/crossref_metadata_2025 huggingface dataset:
Reviews of Maintenance Literature and Models
Authors: Leung Francis K. N.
Published: February 2011

Modeling of the maintenance (inspection, overhaul, repair, replacement, etc.) of deteriorating systems has been of significant importance for the past 70 years, especially because of its applications in industry and medicine. There is an extensive literature on various types of preventive maintenance (PM) policies for stochastically failing single‐unit and multiunit systems. In this article, we review part of the literature that deals with the problem of PM of a stochastically failing single‐unit system. We emphasize how certain features of the various models affect their analysis and the conclusions that can be drawn from them. It should be noted that what we present in this article is only a very small portion of the maintenance field; so many mathematically outstanding papers have been omitted because of space considerations. However, many good surveys, monographs, and handbooks mentioned in this article can provide an extensive overview of the field and can be helpful as guidance through the literature.
Multiarmed Bandits and Gittins Index
Authors: Weber Richard
Published: February 2011

The multiarmed bandit problem is a sequential decision problem about allocating effort (or resources) amongst a number of alternative projects, only one of which may receive effort at a time. For example, we might be allocating the processing effort of a single machine amongst
n
jobs, or allocating research effort amongst
n
drugs that are alternatives for treating some disease. When projects receive effort they generate uncertain rewards. The objective is to maximize an expected discounted sum of rewards over the infinite horizon. The multiarmed bandit problem well points up the trade‐off between exploitation and exploration. On the one hand, we might pursue the project that we currently think offers the greatest expected reward; on the other hand, we might be willing to pass up immediate reward in order to become better informed about the other projects and thereby obtain greater reward later. This article describes the problem, its solution in terms of the Gittins index, some applications, and generalizations.
An Introduction toR&DPortfolio Decision Analysis
Authors: Duncan Kelly J. , Merrick Jason R.W.
Published: February 2011

A portfolio is a purposeful combination of items. For research and development (R&D) portfolios these items are technologies, projects, or products. Companies have widely varying practices for portfolio selection. This article examines existing literature to determine the key characteristics of a good portfolio and how decision analysis is used to find one. The approach needs to handle multiple objectives, account for project interactions, and address the social aspect of decision making. The resulting portfolio should be aligned with business strategy, balanced, and maximize value. The article introduces general concepts that have been used to select portfolios and reviews specific applications.
The Vehicle Routing Problem with Time Windows: State‐of‐the‐Art Exact Solution Methods
Authors: Desaulniers Guy , Desrosiers Jacques , Spoorendonk Simon
Published: February 2011

The vehicle routing problem with time windows (VRPTW) consists of finding least‐cost vehicle routes to service given customers exactly once each while satisfying the vehicle capacity and customer time windows. The VRPTW has been widely studied. We present here a short survey on the successful exact methods for solving it. These are branch‐cut‐and‐price algorithms, except the most efficient one which solves, by a mixed‐integer programming solver, a reduced set partitioning model obtained by performing variable elimination based on reduced cost. This method was able to solve all well‐known Solomon's benchmark instances except one, outperforming all the other algorithms previously published.
Semi‐Infinite Programming
Authors: Guerra‐Vázquez Francisco , Rückmann Jan‐J.
Published: February 2011

This article presents a short introduction to semi‐infinite programming (SIP), which over the last two decades has become a vivid research area in mathematical programming with a wide range of applications. An SIP problem is characterized by infinitely many inequality constraints in a finite‐dimensional space. We consider first and second order optimality conditions as well as the reduction approach, which allows a local reduction of an SIP problem to a finite programming problem. Furthermore, we discuss several stability concepts including the strong stability of a stationary point and the structural stability. Finally, we briefly refer to solution methods and generalized semi‐infinite programming problems.
Public Health, Emergency Response, and Medical PreparednessIII: Communication Infrastructure
Authors: Lee Eva K. , Yang Anna Yang , Guilford Tyrus , Pietz Ferdinand , Benecke Bernard
Published: February 2011

Developing and maintaining a robust communication infrastructure among hospitals, emergency medical services, and other health‐care facilities, as well as private medical transport companies and medical supplies vendors, is vital to providing relief operations and services during emergency situations. Such infrastructure provides the core foundation for basic knowledge‐sharing such as patient volume and severity, emergency room capacity, hospital bed availability; special wards availability; medical personnel specialties; transport vehicle availability; and blood, medicine, and medical supplies inventories. During an emergency situation, such critical information can be communicated to a regional coordinating control center, which can assess available resources, identify surpluses and shortages, and coordinate distribution efforts. In fact, building capacity for an interoperable communication system for emergency response is identified as one of the areas that must be prioritized according to The Hospital Preparedness Program established by the US Department of Health and Human Services. In this article, we highlight some important issues related to an effective communication infrastructure. Various communication tools and infrastructure will be contrasted. Organizational and sociological factors as well as human behavior are discussed. Beyond communicating horizontally and vertically across the jurisdictions and federal, state, and local government agencies, we also highlight the importance of multimedia public information and risk communication factors that are essential for mounting an effective emergency response.
Operations Research in Forestry and Forest Products Industry
Authors: D'Amours Sophie , Epstein Rafael , Weintraub Andres , Rönnqvist Mikael
Published: February 2011

Over the years, operational research (OR) has been used extensively to support the forest products industry and public forestry organizations in their respective planning activities concerning the flow of wood fiber from the forest to the customer. The planning decisions range from long‐term strategic planning decisions related to forest management or company development to very short‐term operational decisions, such as planning for real‐time log/chip transportation or cutting. This chapter presents an overview of the different planning problems and explains how these are solved in the field of forestry using operational research.
Introduction to Tabu Search
Authors: Smith J. Cole , Cochran James J.
Published: February 2011

This article provides an introductory treatment to tabu search, which is one of the most popular metaheuristic methods for solving difficult combinatorial optimization problems. Tabu search is based on local search, but attempts to avoid early termination at local optima, as these might have objective function values that are far inferior to the globally optimal one. Tabu search employs a limited memory of attributes of recent moves to avoid move reversals and looping, and also to guide the search procedure into unexplored areas of the solution space, thus improving the likelihood of finding a near‐optimal solution. We present the basic tabu search approach, discuss common enhancements with respect to implementing this method, and provide a brief review of sample applications to which tabu search has been effectively applied.
Mapping of Domain Orientation and Molecular Order in Polycrystalline Semiconducting Polymer Films with Soft X‐Ray Microscopy
Authors: Watts Benjamin , Schuettfort Torben , McNeill Christopher R.
Published: February 2011

We utilize scanning transmission X‐ray microscopy (STXM) to study the domain structure of polycrystalline films of the semiconducting polymer poly(9,9’‐dioctylfluorene‐co‐benzothiadiazole) (F8BT). By taking several images at different orientations of the film with respect to the polarization of the X‐ray beam, we are able to compute quantitative maps of molecular alignment/order and molecular orientation, including both the backbone direction and phenyl ring plane orientation, as well as the in‐plane and out‐of‐plane components. We show that polycrystalline F8BT films consist of well‐ordered micron‐sized domains with the transition from one domain orientation to another characterized either by a smooth transition of orientation or by ∼ 200 nm wide disordered domain boundaries. The morphology of the disordered domain boundaries resemble the electroluminescence patterns observed previously in F8BT light‐emitting field‐effect transistors suggesting that charge trapping at these disordered domain boundaries facilitates charge recombination in ambipolar operation. A relatively narrow distribution of local average tilt angles is observed that correlates with film structure, with the ordered domains in general showing a higher tilt angle than the disordered domain boundaries. We also use secondary electron detection to image the surface domain structure of polycrystalline F8BT films and demonstrate that the polycrystalline structure extends to the film/air interface. Finally, we calculate ideal NEXAFS spectra corresponding to a perfect F8BT crystal oriented with the 1s – π* transition dipole moment parallel and perpendicular to the electric field vector of a perfectly linearly polarized X‐ray beam.
Emerging Transparent Electrodes Based on Thin Films of Carbon Nanotubes, Graphene, and Metallic Nanostructures
Authors: Hecht David S. , Hu Liangbing , Irvin Glen
Published: February 2011

Transparent electrodes are a necessary component in many modern devices such as touch screens, LCDs, OLEDs, and solar cells, all of which are growing in demand. Traditionally, this role has been well served by doped metal oxides, the most common of which is indium tin oxide, or ITO. Recently, advances in nano‐materials research have opened the door for other transparent conductive materials, each with unique properties. These include CNTs, graphene, metal nanowires, and printable metal grids. This review will explore the materials properties of transparent conductors, covering traditional metal oxides and conductive polymers initially, but with a focus on current developments in nano‐material coatings. Electronic, optical, and mechanical properties of each material will be discussed, as well as suitability for various applications.
Iron‐Doped Single‐Walled Carbon Nanotubes as New Heterogeneous and Highly Efficient Catalyst for Acylation of Alcohols, Phenols, Carboxylic Acids and Amines under Solvent‐Free Conditions
Authors: Sharghi Hashem , Jokar Mahboubeh , Doroodmand Mohammad Mahdi
Published: February 2011

Iron‐doped single‐walled carbon nanotubes (Fe/SWCNTs) represent an efficient and new heterogeneous reusable catalyst for the acylation of a variety of alcohols, phenols, carboxylic acids and amines with acid chlorides or acid anhydrides under solvent‐free conditions. The reactions of various primary, secondary, tertiary, and benzylic alcohols, diols, phenols, as well as aromatic and aliphatic amines give acylated adducts in good to excellent yields.
One‐Pot Synthesis of Spirooxindole Derivatives Catalyzed by Lipase in the Presence of Water
Authors: Chai She‐Jie , Lai Yi‐Feng , Xu Jiang‐Cheng , Zheng Hui , Zhu Qing , Zhang Peng‐Fei
Published: February 2011

A facile one‐pot synthesis route to spirooxindole derivatives was developed by combining the three types of catalytic activities of lipase from porcine pancreas (PPL) in the presence of water, i.e., the Knoevengel condensation, Michael addition and cyclization. PPL showed excellent catalytic activity and have a good adaptability to different substrates in the reaction. All the reactions go smoothly and provide spirooxindole derivatives with high yield under the mild conditions. This lipase‐catalyzed multistep conversion method has provided a new strategy to synthesize spirooxindole derivatives and expanded the application of biocatalysts.
Synthesis of 3H‐Quinazolin‐4‐ones and 4H‐3,1‐Benzoxazin‐4‐ones via Benzylic Oxidation and Oxidative Dehydrogenation using Potassium Iodide‐tert‐Butyl Hydroperoxide
Authors: Kumar R. Arun , Maheswari C. Uma , Ghantasala Satheesh , Jyothi C. , Reddy K. Rajender
Published: February 2011

A simple and elegant method for benzylic activation was demonstrated employing the potassium iodide/tert‐butyl hydrogen peroxide catalytic system. This methodology was further extended for the synthesis of biologically important heterocycles namely, 3H‐quinazolin‐4‐ones and 4H‐3,1‐benzoxazin‐4‐ones including mecloqualone and etaqualone which are important quinazolinone‐based drugs used for the treatment of insomnia in good yields.
Gold‐Catalyzed Cascade Friedel–Crafts/Furan‐Yne Cyclization/Heteroenyne Metathesis for the Highly Efficient Construction of Phenanthrene Derivatives
Authors: Chen Yifeng , Li Guijie , Liu Yuanhong
Published: February 2011

A rapid access to highly substituted phenanthrenyl ketones through gold‐catalyzed cyclization of 1,6‐diyn‐4‐en‐3‐ols with furans has been developed. Gold catalysts are effective to catalyze three cascade processes involving Friedel–Crafts/furan‐yne cyclization/heteroenyne metathesis through CO bond and alkyne activation. This method offers several advantages such as high selectivities and easily accessible starting materials.
Calcium‐Catalyzed Direct Amination of π‐Activated Alcohols
Authors: Haubenreisser Stefan , Niggemann Meike
Published: February 2011

A calcium‐catalyzed direct amination of π‐activated alcohols with different nitrogen nucleophiles under very mild reaction conditions is presented. The high reactivity of the calcium catalyst allows for an efficient conversion of secondary and tertiary benzylic and allylic as well as tertiary propargylic alcohols. Nitrogen nucleophiles such as carbamates, tosylamides and anilines are readily alkylated at room temperature.
Highly Enantio‐ and Diastereoselective Synthesis of γ‐Amino Alcohols from α,β‐Unsaturated Imines through a One‐Pot β‐Boration/Reduction/Oxidation Sequence
Authors: Solé Cristina , Whiting Andrew , Gulyás Henrik , Fernández Elena
Published: February 2011

A simple one‐pot three‐step synthetic route towards chiral γ‐amino alcohols has been established. Considering the overall stereocontrol of the synthetic protocol, the first and key step is the enantioselective β‐boration of α,β‐unsaturated imines. By screening a small library of potential chiral auxiliaries, several chiral phosphorus ligands have been identified which induce exceptional enantioselectivities (up to 99% ee). For the stoichiometric reduction of the imino group, it has been found that high levels of 1,3‐diastereocontrol can be achieved using achiral reducing agents. A new methodology for the synthesis of both diastereoisomers, syn and anti, has been established. The last step of the reaction sequence, oxidative substitution of the boryl unit with a hydroxy group, proceeds with complete retention of the configuration at the Cβ‐atom. Most importantly, the three simple steps can be carried out in one pot without significant change in the overall stereoselectivity.
Combined Rhodium/Gold Catalysis: From Propargyloxiranes to 2,5‐Dihydrofurans in One Pot
Authors: Aksın‐Artok Özge , Krause Norbert
Published: February 2011

A new and efficient one‐pot synthesis of 2,5‐dihydrofurans from propargyloxiranes and arylboronic acids takes advantage of sequential rhodium‐gold catalysis. The transformation proceeds with center‐to‐axis‐to‐center chirality transfer and tolerates a wide variety of electron‐accepting or electron‐withdrawing substituents at the arylboronic acid, as well as cyclic or acyclic propargyloxiranes.
Studies on the release of ibuprofen from Al3+ ion cross‐linked homopolymeric and interpenetrating network hydrogel beads of carboxymethyl xanthan and sodium alginate
Authors: Ray Rajat , Maity Siddhartha , Mandal Sanchita , Chatterjee Tapan Kumar , Sa Biswanath
Published: February 2011

Homopolymeric and interpenetrating network (IPN) hydrogel beads of ibuprofen (IBP), a nonsteroidal anti‐inflammatory drug, were prepared using carboxymethyl xanthan and sodium alginate as polymers and AlCl3 as a cross‐linking agent. Formation of IPN structure was examined using FTIR analysis. The effect of composition of the hydrogel beads and the amount drug load on the release of IBP was studied in acidic and phosphate buffer (PB) solution of pH 6.8. In accordance with the swelling behavior of the beads, drug release from the IPN beads in acidic solution was found to be confined within those from homopolymeric beads. On the other hand, drug release from IPN beads in PB solution was found to be less than those from the homopolymeric beads although the swelling of the beads followed the same trend as in an acidic solution. An increase in the drug load further decreased the drug release from all the beads in both the dissolution media. FTIR, XRD, and DSC analyses demonstrated the absence of any interaction between the drug and the polymers. The results indicated that IPN hydrogel beads provided more sustained release of IBP than homopolymeric beads. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30:1–11, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20199
Solvent effects on the thermal and mechanical properties of poly(methyl methacrylate) casted from concentrated solutions
Authors: Patra Niranjan , Barone Alberto C. , Salerno Marco
Published: February 2011

The thermal, mechanical, and structural properties of poly(methyl methacrylate) (PMMA) samples casted from solutions of chloroform, toluene, and N,N‐dimethylformamide (DMF) were investigated by means of differential scanning calorimetry, nanoindentation, and Fourier transform infrared spectroscopy, respectively. The thermal analysis showed that for PMMA prepared from chloroform and toluene solutions the glass transition temperature was quite lower than for bulk PMMA, whereas for PMMA prepared from the DMF solution it was higher. The mechanical analysis showed higher reduced modulus and lower creep effect for PMMA prepared from the DMF solution than for PMMA prepared from the chloroform and toluene solutions. The spectroscopic analysis pointed out the formation of a strong bond between the polymer carbonyl group and the solvent amide group for the PMMA prepared from the DMF solution and a significant distortion of the polymer chain for the PMMA prepared from the chloroform and toluene solutions. Therefore, the observed thermal and mechanical behavior is ascribed to the different hydrogen bonding contributions, the rotation of the end group, and the distortion of the polymer chain. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30:12–20, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20203
Effect of packing pressure on refractive index variation in injection molding of precision plastic optical lens
Authors: Yang Can , Su Lijuan , Huang Chunning , Huang Han‐Xiong , Castro Jose M. , Yi Allen Y.
Published: February 2011

In this study, refractive index variation in injection‐molded polymethylmethacrylate optical lenses under different levels of packing pressure was evaluated using a Shack–Hartmann wavefront sensor‐based metrology system. The experimental results showed that optical polymer's refractive index exhibits a considerable amount of variation for the lenses molded under different packing pressures. Specifically, within the range investigated in this study, refractive index variation is more uniform when higher packing pressure was used but less so for lower packing pressure. Refractive index variation is believed to be the result of density variation, which itself is caused by shrinkage variation at different packing conditions. In addition, using density information in the plastic lenses predicted by finite element simulation, refractive index variation was numerically determined using the differential Lorentz–Lorenz equation and the results were in good agreement with the experiments conducted in this research. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30:51–61, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20211
Polymer Blend Solar Cells Based on a High‐Mobility Naphthalenediimide‐Based Polymer Acceptor: Device Physics, Photophysics and Morphology
Authors: Moore Jennifer R. , Albert‐Seifried Sebastian , Rao Akshay , Massip Sylvain , Watts Benjamin , Morgan David J. , Friend Richard H. , McNeill Christopher R. , Sirringhaus Henning
Published: February 2011

A high electron mobility polymer, poly{[N,N’‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5’‐(2,2’‐bithiophene) (P(NDI2OD‐T2)) is investigated for use as an electron acceptor in all‐polymer blends. Despite the high bulk electron mobility, near‐infrared absorption band and compatible energy levels, bulk heterojunction devices fabricated with poly(3‐hexylthiophene) (P3HT) as the electron donor exhibit power conversion efficiencies of only 0.2%. In order to understand this disappointing photovoltaic performance, systematic investigations of the photophysics, device physics and morphology of this system are performed. Ultra‐fast transient absorption spectroscopy reveals a two‐stage decay process with an initial rapid loss of photoinduced polarons, followed by a second slower decay. This second slower decay is similar to what is observed for efficient P3HT:PCBM ([6,6]‐phenyl C61‐butyric acid methyl ester) blends, however the initial fast decay that is absent in P3HT:PCBM blends suggests rapid, geminate recombination of charge pairs shortly after charge transfer. X‐ray microscopy reveals coarse phase separation of P3HT:P(NDI2OD‐T2) blends with domains of size 0.2 to 1 micrometer. P3HT photoluminescence, however, is still found to be efficiently quenched indicating intermixing within these mesoscale domains. This hierarchy of phase separation is consistent with the transient absorption, whereby localized confinement of charges on isolated chains in the matrix of the other polymer hinders the separation of interfacial electron‐hole pairs. These results indicate that local, interfacial processes are the key factor determining the overall efficiency of this system and highlight the need for improved morphological control in order for the potential benefit of high‐mobility electron accepting polymers to be realized.
Ethnic differences in patterns of occupational exposure in New Zealand
Authors: Eng Amanda , 't Mannetje Andrea , Ellison‐Loschmann Lis , McLean Dave , Cheng Soo , Pearce Neil
Published: February 2011

Objectives

To investigate the differences in occupational exposure between Māori (New Zealand's indigenous people) and non‐Māori.

Methods

Participants were randomly selected from the Electoral Roll. Exposure to occupational risk factors was assessed through telephone interviews and exposure prevalences of Māori (n = 273) and non‐Māori (n = 2,724) were compared. Subsequently, Māori were matched with non‐Māori on current occupation (n = 482) to assess whether ethnic differences also exist within occupations.

Results

Māori were more likely to report exposure to physical strain (e.g., lifting, standing). Part of these differences remained when Māori were compared with non‐Māori in the same job. In addition, Māori women were twice as likely to categorize their job as very or extremely stressful than non‐Māori women in the same job, while Māori men were twice as likely to report exposure to dust.

Conclusion

Marked ethnic differences exist in risk factors for occupational ill‐health, due to both occupational distribution and the distribution of tasks within occupations. Am. J. Ind. Med. 54:410–418, 2011. © 2011 Wiley‐Liss, Inc.
Cancer incidence and mortality among workers exposed to benzidine
Authors: Brown Shannon Cameron , Alberts Risa , Schoenberg Mark
Published: February 2011

Background

A historical cohort study was conducted among 997 individuals employed at a chemical production facility to investigate whether occupational exposures to benzidine and other arylamines were associated with the increased risk of cancer.

Methods

Cancers were identified from cancer registries, death certificates, and medical records. Exposures were evaluated using a job‐exposure matrix. Workers were categorized into exposure groups to calculate cancer‐specific standardized incidence ratios (SIRs) and perform survival analyses.

Results

SIRs for cancer of the bladder (SIR = 3.5; CI 1.7, 6.4), small intestine (SIR 18.4; CI 2.2, 66.4), and soft tissue including heart (SIR = 11.9; CI 1.4, 42.8) were elevated among workers with the highest exposures and risk increased with increasing exposures. SIRs for several additional cancers were also elevated.

Conclusion

Our results support previous findings of increased risk of bladder cancer among individuals exposed to benzidine and other arylamines. Workers may also have been at increased risk for cancers other than cancer of the bladder. Am. J. Ind. Med. 54:300–306, 2011. © 2011 Wiley‐Liss, Inc.
Assessing occupational health and safety of young workers who use youth employment centers
Authors: Breslin F. Curtis , Morassaei Sara , Wood Matt , Mustard Cameron A.
Published: February 2011

Background

Adolescents and young adults who are out of school are at elevated risk for a work injury.

Methods

To obtain more information on this “high risk” group of young workers, young people at youth employment centers across Ontario were asked through an online survey about training, unsafe work conditions, work injuries and safety knowledge.

Results

The 1,886 youth who completed the survey reported a medically attended work injury rate of 14.45 per 100 FTEs. Also, the most common unsafe work conditions were dust/particles, trip hazards and heavy lifting. In addition, many young workers reported using much of their income for living essentials (e.g., rent).

Conclusions

Though not a representative sample, it appears that youth using employment centers experience many unsafe work conditions and work injuries. While many report safety training, the nature and effectiveness of this training remains to be determined. The large portion of young workers out of school and working for living essentials included in this sample suggest that youth employment centers should be considered in future prevention efforts targeting this vulnerable subgroup of workers. Am. J. Ind. Med. 54:325–337, 2011. © 2011 Wiley‐Liss, Inc.
Understanding emotions in primates: in honor of Darwin's 200th birthday
Authors: Fragaszy Dorothy , Simpson Elizabeth
Published: February 2011

In the bicentenary year of Darwin's birth, the American Society of Primatologists honored his memory by convening a symposium entitled “Understanding emotions in primates: In honor of Darwin's 200th birthday.” The four articles in this special section, excepting this introduction, derive from that symposium. The section confirms that the topic of emotion is once again, as in Darwin's lifetime, the subject of wide‐ranging, theoretically exciting research, and that studies with nonhuman primates are at the leading edge of a rapidly changing field. Am. J. Primatol. 73:503–506, 2011. © 2011 Wiley‐Liss, Inc.
From Conventional to Unusual Enzyme Inhibitor Scaffolds: The Quest for Target Specificity
Authors: Meggers Eric
Published: February 2011

The tremendous challenge presented by the specific molecular recognition of single biomacromolecular targets within complex biological systems demands novel and creative design strategies. This Minireview discusses some conventional and unusual approaches for the design of target‐selective enzyme inhibitors with a focus on the underlying chemical scaffolds. These include complicated natural‐product‐like organic molecules, stable octahedral metal complexes, fullerenes, carboranes, polymetallic clusters, and even polymers. Thus the whole repertoire of organic, inorganic, and macromolecular chemistry can be applied to tackle the problem of target‐specific enzyme inhibition.
Photoreactive s‐triazine as crosslinking agents for UV‐crosslinkable acrylic pressure‐sensitive adhesives
Authors: Czech Zbigniew , Butwin Agnieszka , Kabatc Janina
Published: February 2011

The UV‐crosslinking as an established technology has been used in many industrial manufacturing processes. New application and technical specifications of UV‐crosslinking lead to continuous development of tailor‐made photoinitiators which can efficiently meet specific requirements. A new class of radical reactive photoinitiators based on s‐triazine has been used for crosslinking of acrylic pressure‐sensitive adhesives containing double bonds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Encapsulation of disperse dye by phase separation technique using poly(styrene‐maleic acid)
Authors: Fu Shaohai , Zhang Guifang , Ding Lei , Tian Anli , Wang Chaoxia
Published: February 2011

C.I. disperse dye blue 60 was encapsulated by poly(styrene‐maleic acid) using phase separation technique, followed by the preparation of the encapsulated disperse dye dispersion. The effects of process conditions on particle size of the dispersion were investigated. The results showed that the particle size of the encapsulated disperse dye dispersion was small, and the stability was excellent when mass ratio of poly(styrene‐maleic acid) to disperse dye (Rp/d), dropping speed of phase separation agent (Ds), disperse dye content in dispersion (Cd), and dispersing time (Dt) were about 20%, 7 mL/min, 5–7.5%, and 1.5 h, respectively. Transmission electron microscope (TEM), zeta potentials, and contact angle indicated that C.I. disperse dye blue 60 was successfully encapsulated by poly(styrene‐maleic acid). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Influence of graphite nanosheets on the structure and properties of PVC‐based nanocomposites
Authors: Al‐Hartomy Omar A. , Al‐Salamy Falleh , Al‐Ghamdi Ahmed A. , Abdel Fatah M. , Dishovsky Nikolay , El‐Tantawy Farid
Published: February 2011

Polyvinyl chloride‐ (PVC)‐ based nanocomposites, containing graphite nanosheets (G), which may be used as electromagnetic wave absorbers was developed and investigated. The microstructure of polyvinyl chloride/graphite nanocomposites (PVC/G) were examined by means of X ‐ray diffraction, scanning electron microscopy (SEM), and thermal gravimetric analyses (TGA). SEM image reveals that the graphite nanosheets were well dispersed in the PVC matrix without agglomeration. Thermal stability of the PVC/G nanocomposites is improved as a result of inclusion of graphite nanosheets. The PVC/G nanocomposites were characterized to investigate the effect of dispersion of graphite nanosheets in PVC matrix. The dielectric spectroscopy of PVC/G nanocomposites in frequency range from 1 to 12 GHz has been performed. The results show that PVC/G nanocomposites exhibit high dielectric constant at the measured frequencies. Coefficient of attenuation and coefficient of reflection of PVC/G composites have been also examined in a frequency range from 1 to 12 GHz. The electromagnetic interference shielding effectiveness (EMI) depends on graphite volume fraction in the composite. The results show that the PVC/G represents a new class of conducting lightweight nanomaterial that can absorb electromagnetic waves at microwave frequency and may be promising for future commercial use. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
PVDF/CB composites prepared by novel solvent casting method for low voltage PTC temperature regulation applications
Authors: Acott Samuel M. , Parsons Tamsin M. , Nevell James M. , Perera Semali P.
Published: February 2011

A novel solvent casting preparation technique utilizing three variants of poly(vinylidene fluoride) (PVDF) to achieve a thermal cut off and a self regulation effect at a low applied voltage is reported in this study. The positive temperature coefficient (PTC) composites were prepared by dissolving PVDF in 1‐methyl‐2‐pyrrolidone (NMP) solvent, blending with Vulcan® XC72 carbon black (CB) filler, crosslinking with vinyl trimethoxysilane (VTMOS) and quenching in water. All composites displayed a highly macrovoidal structure that promoted a PTC effect when subjected to a thermal expansion effect via an electrical current. Subsequently the current was cut off and self regulation behavior was exhibited. Kynar® 761A PVDF resulted in the strongest PTC effect, and displayed temperature regulation at around 100°C which may be attributed to the highly semi crystalline nature and the larger molecular weight of this polymer in comparison with the other PVDF composites studied. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Exploring Femoral Diaphyseal Shape Variation in Wild and Captive Chimpanzees by Means of Morphometric Mapping: A Test of Wolff's Law
Authors: Morimoto Naoki , De León Marcia S. Ponce , Zollikofer Christoph P.E.
Published: February 2011

Long bone shafts (diaphyses) serve as load‐bearing structures during locomotion, implying a close relationship between diaphyseal form and its locomotor function. Diaphyseal form‐function relationships, however, are complex, as they are mediated by various factors such as developmental programs, evolutionary adaptation, and functional adaptation through bone remodeling during an individual's lifetime. The effects of the latter process (“Wolff's Law”) are best assessed by comparing diaphyseal morphologies of conspecific individuals under different locomotor regimes. Here we use morphometric mapping (MM) to analyze the morphology of entire femoral diaphyses in an ontogenetic series of wild and captive common chimpanzees (Pan troglodytes troglodytes). MM reveals patterns of variation of diaphyseal structural and functional properties, which cannot be recognized with conventional cross‐sectional analysis and/or geometric morphometric methods. Our data show that diaphyseal shape, cortical bone distribution and inferred cross‐sectional biomechanical properties vary both along ontogenetic trajectories and independent of ontogeny. Mean ontogenetic trajectories of wild and captive chimpanzees, however, were found to be statistically identical. This indicates that the basic developmental program of the diaphysis is not altered by different loading conditions. Significant differences in diaphyseal shape between groups could only be identified in the distal diaphysis, where wild chimpanzees exhibit higher mediolateral relative to anteroposterior cortical bone thickness. Overall, thus, the hypothesis that Wolff's Law predominantly governs long bone diaphyseal morphology is rejected. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
The proportional lack of archaeal pathogens: Do viruses/phages hold the key?
Authors: Gill Erin E. , Brinkman Fiona S. L.
Published: February 2011

Although Archaea inhabit the human body and possess some characteristics of pathogens, there is a notable lack of pathogenic archaeal species identified to date. We hypothesize that the scarcity of disease‐causing Archaea is due, in part, to mutually‐exclusive phage and virus populations infecting Bacteria and Archaea, coupled with an association of bacterial virulence factors with phages or mobile elements. The ability of bacterial phages to infect Bacteria and then use them as a vehicle to infect eukaryotes may be difficult for archaeal viruses to evolve independently. Differences in extracellular structures between Bacteria and Archaea would make adsorption of bacterial phage particles onto Archaea (i.e. horizontal transfer of virulence) exceedingly hard. If phage and virus populations are indeed exclusive to their respective host Domains, this has important implications for both the evolution of pathogens and approaches to infectious disease control.
Prediction of the binding mode between GSK3β and a peptide derived from GSKIP using molecular dynamics simulation
Authors: Tang Xu‐Nan , Lo Cheng‐Wei , Chuang Yu‐Chung , Chen Chao‐Tung , Sun Ying‐Chieh , Hong Yi‐Ren , Yang Chia‐Ning
Published: February 2011

GSK3β plays an important role in many physiological functions; dysregulated GSK3β is involved in human diseases such as diabetes, cancer, and Alzheimer's disease. This study uses MD simulations to determine the interaction between GSK3β and a peptide derived from GSKIP, a novel GSK3β interacting protein. Results show that GSKIPtide is inlaid in a binding pocket consisting of an α‐helix and an extended loop near the carboxy‐terminal end. This binding pocket is hydrophobic, and is responsible for the protein–protein interaction of two other GSK3β interacting proteins: FRAT and Axin. The GSKIPtide binding mode is closer to that of AxinGID (in the Axin‐GSK3‐interacting domain). The single‐point mutations of V267G and Y288F in GSK3β differentiate the binding modes between GSK3 and GSKIPtide, AxinGID, and FRATide. The V2677G mutation of GSK3β reduces the GSKIPtide binding affinity by 70% and abolishes the binding affinity with AxinGID, but has no effect on FRATide. However, GSK3β Y288F completely abolishes the FRATide binding without affecting GSKIPtide or AxinGID binding. An analysis of the GSK3β–GSKIPtide complex structure and the X‐ray crystal structures of GSK3β‐FRATide and GSK3β‐AxinGID complexes suggests that the hydroxyl group of Y288 is crucial to maintaining a hydrogen bond network in GSK3β‐FRATide. The hydrophobic side chain of V267 maintains the integrity of helix–helix ridge‐groove hydrophobic interaction for GSK3β‐GSKIPtide and GSK3β‐AxinGID. This study simulates these two mutant systems to provide atomic‐level evidence of the aforementioned experimental results and validate the wild‐type complex structure prediction. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 461–471, 2011.
Time resolved SAXS and RNA folding
Authors: Pollack Lois
Published: February 2011

Small angle X‐ray scattering provides low resolution structural information about macromolecules in solution. When coupled with rapid mixing methods, SAXS reports time‐dependent conformational changes of RNA induced by the addition of Mg2+ to trigger folding. Thus time‐resolved SAXS provides unique information about the global or overall structures of transient intermediates populated during folding. Notably, SAXS provides information about the earliest folding events, which can evade detection by other methods. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 543–549, 2011.
Ion channel electrophysiology via integrated planar patch‐clamp chip with on‐demand drug exchange
Authors: Chen Chang‐Yu , Tu Ting‐Yuan , Jong De‐Shien , Wo Andrew M.
Published: February 2011

Planar patch clamp has revolutionized characterization of ion channel behavior in drug discovery primarily via advancement in high throughput. Lab use of planar technology, however, addresses different requirements and suffers from inflexibility to enable wide range of interrogation via a single cell. This work presents integration of planar patch clamp with microfluidics, achieving multiple solution exchanges for tailor‐specific measurement and allowing rapid replacement of the cell‐contacting aperture. Studies via endogenously expressed ion channels in HEK 293T cells were commenced to characterize the device. Results reveal the microfluidic concentration generator produces distinct solution/drug combination/concentrations on‐demand. Volume‐regulated chloride channel and voltage‐gated potassium channels in HEK 293T cells immersed in generated solutions under various osmolarities or drug concentrations show unique channel signature under specific condition. Excitation and blockage of ion channels in a single cell was demonstrated via serial solution exchange. Robustness of the reversible bonding and ease of glass substrate replacement were proven via repeated usage of the integrated device. The present approach reveals the capability and flexibility of integrated microfluidic planar patch‐clamp system for ion channel assays. Biotechnol. Bioeng. 2011; 108:1395–1403. © 2011 Wiley Periodicals, Inc.
Construction of an E. Coli genome‐scale atom mapping model for MFA calculations
Authors: Ravikirthi Prabhasa , Suthers Patrick F. , Maranas Costas D.
Published: February 2011

Metabolic flux analysis (MFA) has so far been restricted to lumped networks lacking many important pathways, partly due to the difficulty in automatically generating isotope mapping matrices for genome‐scale metabolic networks. Here we introduce a procedure that uses a compound matching algorithm based on the graph theoretical concept of pattern recognition along with relevant reaction information to automatically generate genome‐scale atom mappings which trace the path of atoms from reactants to products for every reaction. The procedure is applied to the iAF1260 metabolic reconstruction of Escherichia coli yielding the genome‐scale isotope mapping model imPR90068. This model maps 90,068 non‐hydrogen atoms that span all 2,077 reactions present in iAF1260 (previous largest mapping model included 238 reactions). The expanded scope of the isotope mapping model allows the complete tracking of labeled atoms through pathways such as cofactor and prosthetic group biosynthesis and histidine metabolism. An EMU representation of imPR90068 is also constructed and made available. Biotechnol. Bioeng. 2011; 108:1372–1382. © 2011 Wiley Periodicals, Inc.
Modulation of antibody galactosylation through feeding of uridine, manganese chloride, and galactose
Authors: Gramer Michael J. , Eckblad Jackie J. , Donahue Ruth , Brown Joseph , Shultz Carrie , Vickerman Kent , Priem Patrick , van den Bremer Ewald T.J. , Gerritsen Jolanda , van Berkel Patrick H.C.
Published: February 2011

Through process transfer and optimization for increased antibody production to 3 g/L for a GS‐CHO cell line, an undesirable drop in antibody Fc galactosylation was observed. Uridine (U), manganese chloride (M), and galactose (G), constituents involved in the intracellular galactosylation process, were evaluated in 2‐L bioreactors for their potential to specifically increase antibody galactosylation. These components were placed in the feed medium at proportionally increasing concentrations from 0 to 20× UMG, where a 1× concentration of U was 1 mM, a 1× concentration of M was 0.002 mM, and a 1× concentration of G was 5 mM. Antibody galactosylation increased rapidly from 3% at 0× UMG up to 21% at 8× UMG and then more slowly to 23% at 20× UMG. The increase was primarily due to a shift from G0F to G1F, with minimal impact on other glycoforms or product quality attributes. Cell culture performance was largely not impacted by addition of up to 20× UMG except for suppression of glucose consumption and lactate production at 16 and 20× UMG and a slight drop in antibody concentration at 20× UMG. Higher accumulation of free galactose in the medium was observed at 8× UMG and above, coincident with achieving the plateau of maximal galactosylation. A concentration of 4× UMG resulted in achieving the target of 18% galactosylation at 2‐L scale, a result that was reproduced in a 1,000‐L run. Follow‐up studies to evaluate the addition of each component individually up to 12× concentration revealed that the effect was synergistic; the combination of all three components gave a higher level of galactosylation than addition of the each effect independently. The approach was found generally useful since a second cell line responded similarly, with an increase in galactosylation from 5% to 29% from 0 to 8× UMG and no further increase or impact on culture performance up to 12× UMG. These results demonstrate a useful approach to provide exact and specific control of antibody galactosylation through manipulation of the concentrations of uridine, manganese chloride, and galactose in the cell culture medium. Biotechnol. Bioeng. 2011; 108:1591–1602. © 2011 Wiley Periodicals, Inc.
Induction of anthraquinone biosynthesis in Rubia cordifolia cells by heterologous expression of a calcium‐dependent protein kinase gene
Authors: Shkryl Y.N. , Veremeichik G.N. , Bulgakov V.P. , Zhuravlev Y.N.
Published: February 2011

Calcium‐dependent protein kinases (CDPKs) play an important role in plant cell responses to stress and pathogenic attack. In this study, we investigated the effect of heterologous expression of the Arabidopsis CDPK gene, AtCPK1, on anthraquinone production in transgenic Rubia cordifolia cells. AtCPK1 variants (a constitutively active, Ca2+‐independent form and a non‐active form used as a negative control) were transferred to callus cells by agrobacterial transformation. Overexpression of the constitutively active, Ca2+‐independent form in R. cordifolia cells caused a 10‐fold increase in anthraquinone content compared with non‐transformed control cells, while the non‐active form of AtCPK1 had no effect on anthraquinone production. Real‐time PCR measurements showed that the activation of anthraquinone biosynthesis in transgenic calli correlated with the activation of isochorismate synthase gene expression. The activator effect of AtCPK1 was stable during prolonged periods of transgenic cell cultivation (more than 3 years) and the transgenic cultures exhibited high growth. Our results provide the first evidence that a CDPK gene can be used for the engineering of secondary metabolism in plant cells. Biotechnol. Bioeng. 2011; 108:1734–1738. © 2011 Wiley Periodicals, Inc.
IgLONs form heterodimeric complexes on forebrain neurons
Authors: McNamee Christine J. , Youssef Sahar , Moss Diana
Published: February 2011

IgLONs are a family of four GPI‐anchored cell adhesion molecules that regulate neurite outgrowth and synaptogenesis and may act as tumour suppressor genes. Recently we have proposed that two members of the IgLON family act as a heterodimeric complex termed DIgLON. Neurons isolated from chick forebrain co‐express all six combinations of IgLONs and the intensity of fluorescence for each pair of IgLONs was highly correlated. Antibody‐patching experiments on forebrain neurons show complex formation for IgLON pairs but not between unrelated GPI‐anchored glycoproteins. Thus IgLONs are the first GPI‐anchored family of glycoproteins shown to form heterodimeric complexes in the plane of the membrane. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and Pro‐Apoptotic Activity of Novel Glycyrrhetinic Acid Derivatives
Authors: Logashenko Evgeniya B. , Salomatina Oksana V. , Markov A. V. , Korchagina Dina V. , Salakhutdinov Nariman F. , Tolstikov Genrikh A. , Vlassov Valentin V. , Zenkova Marina A.
Published: February 2011

Triterpenoids are used for medicinal purposes in many countries. Some, such as oleanolic and glycyrrhetinic acids, are known to be anti‐inflammatory and anticarcinogenic. However, the biological activities of these naturally occurring molecules against their particular targets are weak, so the synthesis of new synthetic analogues with enhanced potency is needed. By combining modifications to both the A and C rings of 18βH‐glycyrrhetinic acid, the novel synthetic derivative methyl 2‐cyano‐3,12‐dioxo‐18βH‐olean‐9(11),1(2)‐dien‐30‐oate was obtained. This derivative displays high antiproliferative activity in cancer cells, including a cell line with a multidrug‐resistance phenotype. It causes cell death by inducing the intrinsic caspase‐dependent apoptotic pathway.