bluuebunny/crossref_metadata_2025 huggingface dataset:
Cochlear nerve deficiency in children with CHARGE syndrome
Authors: Holcomb Meredith A. , Rumboldt Zoran , White David R.
Published: August 2012

Objectives/Hypothesis:

To describe cochlear nerve deficiency and abnormalities of the internal auditory canal (IAC) associated with CHARGE (coloboma, heart defects, atresia choanae, retardation of growth and/or development, genital hypoplasia, and ear anomalies and/or deafness) syndrome.

Study Design:

Case series.

Methods:

In a tertiary children's hospital, children with CHARGE syndrome were evaluated between 2006 and 2009. Morphology of the inner ear, IAC, and cochlear nerves was evaluated along with auditory‐evoked brainstem response results.

Results:

Of the 17 patients with CHARGE diagnosis, 14 ears demonstrated profound sensorineural hearing loss (SNHL). The remaining ears had conductive hearing loss, mixed hearing loss, or mild to moderate SNHL. Computed tomography (CT) evaluation was refused in one case and delayed in one case due to parental decision. Of 30 ears evaluated with CT, 28 (93%) had substantial abnormalities of the inner ear including hypoplasia or aplasia of the semicircular canals and abnormalities of the cochlea and vestibule. CT evaluation revealed cochlear aperture narrowing or occlusion in 16 ears, one of which had normal hearing. The eight most recent patients with profound SNHL (six bilateral SNHL, two unilateral) underwent magnetic resonance imaging (MRI) of the IAC, and 13 of 14 ears with SNHL were noted to have absent or deficient cochlear nerves. CT scans in two ears with profound SNHL revealed normal cochlear apertures.

Conclusions:

The dysmorphic inner ear is well described in CHARGE patients; however, cochlear nerve deficiency has not been considered a common etiology for SNHL in these patients. Because of the implications of cochlear nerve deficiency in therapeutic decision making (i.e., cochlear implantation), MRI evaluation of the eighth nerve should be considered in CHARGE patients with profound SNHL. Laryngoscope, 2013
In vivo imaging of photoreceptor disruption associated with age‐related macular degeneration: A pilot study
Authors: Boretsky Adam , Khan Faraz , Burnett Garrett , Hammer Daniel X. , Ferguson R. Daniel , van Kuijk Frederik , Motamedi Massoud
Published: August 2012

Background and Objective

Age‐related macular degeneration is one of the leading causes of vision loss in the developed world. As the disease progresses, the central part of the retina, called the macula, is compromised leading to a disruption of both structure and visual function. In this study, we investigate the disruption of macular photoreceptor cells in vivo as a function of disease stage in patients with the dry form of age‐related macular degeneration AMD.

Materials and Methods

An investigational confocal Adaptive Optics Scanning Laser Ophthalmoscope (AO–SLO) was used to obtain high resolution images of the macular photoreceptor mosaic in patients previously diagnosed with AMD. Four patients were selected as representative cases, comprising each of the four clinical stages of AMD progression.

Results

AO–SLO imaging revealed slight disruption in the photoreceptor mosaic in early stage AMD due to focal drusen formation and identified several small drusen deposits that were not observed with standard clinical imaging techniques. An increase in photoreceptor disruption was visualized within the macula in direct correlation with the stage of AMD progression leading to a decrease in visual acuity. Large coalescent drusen and areas of geographic atrophy in advanced stage dry AMD exhibited a significant decrease in visible photoreceptor density. Significant decrease in photoreceptor counts (∼35–50%) were observed when comparing earlier stages of AMD progression (Categories I and II) to later stages of the disease (Categories III and IV).

Conclusions

This study demonstrates the capabilities of adaptive optics retinal imaging to monitor disruption of individual photoreceptor cells as a function of disease progression yielding valuable diagnostic findings in early stage AMD beyond what can be learned about the health of photoreceptors using conventional retinal imaging techniques. Lasers Surg. Med. 44: 603–610, 2012. © 2012 Wiley Periodicals, Inc.
Construction of Donor–Acceptor Chromophores in Platinum Polyyne Polymer by [2 + 2] Cycloaddition of Organic Acceptors
Authors: Yuan Yuping , Michinobu Tsuyoshi
Published: August 2012

A thiophene‐containing platinum polyyne polymer was postfunctionalized by a [2 + 2] cycloaddition followed by a cycloreversion of tetracyanoethylene (TCNE) or 7,7,8,8‐tetracyanoquinodimethane (TCNQ), yielding narrow band gap polymers. The quantitative addition of the acceptor molecules was confirmed by combined analytical techniques. The postfunctionalized platinum polyyne polymers displayed charge‐transfer (CT) bands in the visible‐near IR region and potent redox activities. The TCNQ adduct has a stronger electron‐accepting feature than the TCNE adduct, as revealed by the more bathochromically shifted CT band and the lower first reduction potential. The systematic investigation revealed a clear correlation between the optical and electrochemical band gaps.
High‐Shear‐Strength Waterborne Polyurethane/Acrylic Soft Adhesives
Authors: Degrandi‐Contraires Elise , Lopez Aitziber , Reyes Yuri , Asua José M. , Creton Costantino
Published: August 2012

Urethane/acrylic hybrid latex particles are prepared by miniemulsion polymerization for an application as soft adhesives. The polymerization of the acrylic monomers and grafting of an isocyanate functionalized PU on a hydroxyl functionalized monomer (HEMA) take place simultaneously, resulting in a complex PU/acrylic network while avoiding any macroscopic phase separation. Its structure can be tuned by changing the extent of grafting and a specific model is applied to analyze the final polymer microstructure. The resulting materials have a low level of adhesion but display an exceptionally high resistance to shear. Two parameters are varied: the fraction of HEMA in the monomer composition and the diol concentration.

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Celebrities in Advertising: Looking for Congruence or Likability?
Authors: Fleck Nathalie , Korchia Michael , Le Roy Isabelle
Published: August 2012

The choice of a celebrity endorser for a brand is an important topic in advertising and marketing, as considerable time and effort resources are dedicated to finding the right celebrity to represent a given organization. Celebrities used as endorsers in advertisements are often very popular ones. However, from a cognitive point of view (and a more academic one), congruence between brand and celebrity seems to be very important too. Based on affective and cognitive theories to explain endorsement effectiveness, congruence between brand and celebrity is shown to be as effective as celebrity likability. Moreover, congruence between brand and celebrity as well as celebrity likability have an impact on the predisposition toward the ad, which in turn influences brand beliefs and purchase intention.
Celebrity Endorsements and Beyond: New Avenues for Celebrity Branding
Authors: Keel Astrid , Nataraajan Rajan
Published: August 2012

The authors assess the extant research in the area of celebrity endorsement and point out the need for continuing research in celebrity marketing. Suggestions for future research are made in a wide breadth of areas, spanning from celebrity endorsements to novel areas of celebrity branding. The authors propose three celebrity‐branding strategies and discuss the factors that may influence their effectiveness. Other areas for future research in celebrity marketing that are discussed include ethical marketing to vulnerable consumers and social marketing. The authors conclude with suggestions regarding theories and methods that can be used for future research in celebrity marketing.
A subset of papillary thyroid carcinomas contain KRAS mutant subpopulations at levels above normal thyroid
Authors: Myers Meagan B. , McKim Karen L. , Parsons Barbara L.
Published: August 2012

The molecular pathogenesis of papillary thyroid carcinoma (PTC) is largely attributed to chromosomal rearrangements and point mutations in genes within the MAPK pathway (i.e., BRAF and RAS). Despite KRAS being the 6th most frequently mutated gene for all cancers, the reported frequency in thyroid cancer is only 2%. This may be due, in part, to the use of insensitive mutation detection methods such as DNA sequencing. Therefore, using the sensitive and quantitative ACB‐PCR approach, we quantified KRAS codon 12 GGT → GAT and GGT → GTT mutant fraction (MF) in 20 normal thyroid tissues, 17 primary PTC, 2 metastatic PTC, and 1 anaplastic thyroid carcinoma. We observed measurable levels of KRAS codon 12 GAT or GTT mutation in all normal thyroid tissues. For PTCs, 29.4% and 35.3% had KRAS codon 12 GAT and GTT MF above the 95% upper confidence interval for the corresponding MFs in normal thyroid. The highest observed KRAS codon 12 GTT MFs were associated with tumors with follicular characteristics and relatively high levels of tumor necrosis. The results indicate KRAS mutant subpopulations are present in a large number of thyroid tumors, a fact previously unrecognized. The presence of KRAS mutation may indicate a tumor with an aggressive phenotype, thus directing the course of clinical treatment. © 2012 Wiley Periodicals, Inc.
Immediate force loss after eccentric contractions is increased with l‐name administration, a nitric oxide synthase inhibitor
Authors: Corona Benjamin T. , Ingalls Christopher P.
Published: August 2012

Introduction

Nitric oxide (NO) signaling regulates many biological processes in skeletal muscle, wherein aberrant signaling contributes to myopathic conditions (e.g., Duchenne muscular dystrophy). NO has been shown to play a role in muscle regeneration after injury. However, less is known about its role during injury. In this study we aimed to determine whether NO synthase (NOS) inhibition exacerbates functional deficits immediately after the performance of eccentric contractions.

Methods

Wild‐type mouse extensor digitorum longus (EDL) muscles underwent in vitro functional testing in the presence or absence of a non‐specific NOS inhibitor (L‐NAME, 10 mM) before and after performance of 10 eccentric contractions.

Results

After eccentric contractions, Po was reduced by ∽25% for muscle in regular physiological solution but by ∽50% with the addition of L‐NAME (P = 0.009).

Conclusions

Non‐specific blockade of NOS exacerbates functional deficits immediately after eccentric contractions, suggesting that NO signaling protects skeletal muscle from excessive injury in healthy muscle. Muscle Nerve, 2013
Falls and spinal muscular atrophy: Exploring cause and prevention
Authors: Montes Jacqueline , Mcisaac Tara L. , Dunaway Sally , Kamil‐Rosenberg Shirit , Sproule Douglas , Garber Carol Ewing , De vivo Darryl C. , Rao Ashwini K.
Published: August 2012

Introduction: Falls can cause injury and may compromise function in spinal muscular atrophy (SMA) patients. Weakness and gait variability are associated with falls in other neurological disorders, and fatigue is well documented in SMA. The relationship of weakness, fatigue, and gait variability to falls has never been investigated. Methods: Seven ambulatory patients with SMA completed a falls history questionnaire, 6MWT, gait analysis, and strength testing. Pearson correlation coefficients were used to examine associations between these variables. Results: All 7 subjects reported falls in the previous year. Stride‐length variability was significantly associated with falls, unlike strength, fatigue, or other gait variables. Conclusions: Stride‐length variability was the key variable associated with falls. Preventive strategies to avoid falls should be incorporated into patient management plans. Gait analysis provides actionable information not revealed by standard assessments and should be included in clinical trials designed to address the prevention of falls in the SMA population. Muscle Nerve, 2013
A kinematic hardening soil model considering the principal stress rotation
Authors: Yang Yunming , Yu Hai‐Sui
Published: August 2012

In this article, a typical and representative kinematic hardening soil model is first studied to investigate its capabilities to reproduce soil responses under principal stress rotations (PSR). It is found that the model is capable of reproducing the non‐coaxiality very well. It can qualitatively capture the trends of responses of different stress and strain components, without the capability to quantitatively reproduce these responses. Its prediction of volumetric responses is the poorest and can give wrong results in many cases. The underlying reasons for these capabilities and defects are analyzed in detail. The model is subsequently modified to better take into account the PSR influences. An additional new flow rule and plastic modulus for the PSR are developed. One important feature of the model is that it is developed in the general stress space with six stress variables. Therefore, it can take into account multiple PSRs at different directions. Another feature is that it retains the linear stress rate–strain rate relationship, which facilitates its numerical implementations. In addition, the universal characteristic of the theory makes it equally applicable to other kinematic hardening models. Copyright © 2012 John Wiley & Sons, Ltd.
Blood oxygenation level‐dependent (BOLD)‐based techniques for the quantification of brain hemodynamic and metabolic properties – theoretical models and experimental approaches
Authors: Yablonskiy Dmitriy A. , Sukstanskii Alexander L. , He Xiang
Published: August 2012

The quantitative evaluation of brain hemodynamics and metabolism, particularly the relationship between brain function and oxygen utilization, is important for the understanding of normal human brain operation, as well as the pathophysiology of neurological disorders. It can also be of great importance for the evaluation of hypoxia within tumors of the brain and other organs. A fundamental discovery by Ogawa and coworkers of the blood oxygenation level‐dependent (BOLD) contrast opened up the possibility to use this effect to study brain hemodynamic and metabolic properties by means of MRI measurements. Such measurements require the development of theoretical models connecting the MRI signal to brain structure and function, and the design of experimental techniques allowing MR measurements to be made of the salient features of theoretical models. In this review, we discuss several such theoretical models and experimental methods for the quantification of brain hemodynamic and metabolic properties. The review's main focus is on methods for the evaluation of the oxygen extraction fraction (OEF) based on the measurement of the blood oxygenation level. A combination of the measurement of OEF and the cerebral blood flow (CBF) allows an evaluation to be made of the cerebral metabolic rate of oxygen consumption (CMRO2). We first consider in detail the magnetic properties of blood – magnetic susceptibility, MR relaxation and theoretical models of the intravascular contribution to the MR signal under different experimental conditions. We then describe a ‘through‐space’ effect – the influence of inhomogeneous magnetic fields, created in the extravascular space by intravascular deoxygenated blood, on the formation of the MR signal. Further, we describe several experimental techniques taking advantage of these theoretical models. Some of these techniques – MR susceptometry andT2‐based quantification of OEF – utilize the intravascular MR signal. Another technique – quantitative BOLD – evaluates OEF by making use of through‐space effects. In this review, we target both scientists just entering the MR field and more experienced MR researchers interested in the application of advanced BOLD‐based techniques to the study of the brain in health and disease. Copyright © 2012 John Wiley & Sons, Ltd.
Integrated job scheduling and network routing
Authors: Gamst Mette , Pisinger David
Published: August 2012

We consider an integrated job scheduling and network routing problem which appears in Grid Computing and production planning. The problem is to schedule a number of jobs at a finite set of machines, such that the overall profit of the executed jobs is maximized. Each job demands a number of resources which must be sent to the executing machine through a network with limited capacity. A job cannot start before all of its resources have arrived at the machine.

The scheduling problem is formulated as a Mixed Integer Program (MIP) and proved to be
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‐hard. An exact solution approach using Dantzig‐Wolfe decomposition is presented. The pricing problem is the linear multicommodity flow problem defined on a time‐space network. Branching strategies are presented for the branch‐and‐price algorithm and three heuristics and an exact solution method are implemented for finding a feasible start solution. Finally, interior point stabilization is used to decrease the number of columns generated in the branch‐and‐price algorithm.

The algorithm is experimentally evaluated on job scheduling instances for a Grid network. The Dantzig‐Wolfe algorithm with stabilization is clearly superior, being able to solve large instances with 1,000 jobs and 1,000 machines covering 24 hours of scheduling activity on a Grid network. The algorithm is also compared to simulations of a real‐life Grid, and results show that the solution quality significantly increases when solving the problem to optimality. The promising results indicate that the algorithm can be used as an actual scheduling algorithm in the Grid or as a tool for analyzing Grid performance when adding extra machines or jobs. © 2012 Wiley Periodicals, Inc. NETWORKS, 2013
Reverse multistar inequalities and vehicle routing problems with a lower bound on the number of customers per route
Authors: Gouveia Luis , Riera‐Ledesma Jorge , Salazar‐González Juan‐José
Published: August 2012

This article analyzes inequalities derived by projecting out the flow variables of a single‐commodity flow model for a vehicle routing problem. These inequalities are called reverse multistar (RMS) inequalities and are related to the MS inequalities analyzed and used in other articles. Although the MS RMS inequalities are irrelevant for some vehicle routing problems, in others they are fundamental. The article presents a vehicle routing problem in which the RMS are of interest. It is called the vehicle routing problem with lower and upper bound capacities (LU‐VRP). It concerns a vehicle routing problem with one depot and a homogeneous fleet of vehicles. All the customers have a unit demand, and there are upper and lower bounds on the demand covered by each vehicle. New families of inequalities are derived by strengthening the RMS inequalities. Computational experiments show that the new inequalities are useful when solving LU‐VRP instances. The experiments are based on variations of symmetric and asymmetric VRP library (VRPLIB) instances with up to 100 customers. The constraint on a minimum number of customers served in each route is implicit in the unit‐demand capacitated vehicle routing problem with a fixed number of vehicles. Therefore, the article also evaluates the impact of using the lower bound inequalities developed in the context of this variant. It is still unknown whether the new inequalities can help solve it or not. Our theoretical analysis suggests that one of the families of developed inequalities is not implied by other standard inequalities. This prompts us to pursue studies in the search for other families of lower bound based inequalities for this variant. © 2012 Wiley Periodicals, Inc. NETWORKS, 2013
Using simulation to improve the decision‐making process
Authors: Agatstein Kevin , Rieley James B.
Published: August 2012

All organizations face the same problem of ensuring that their decision‐making process is as effective as possible. Decision‐making techniques range greatly—from a command‐and‐control hierarchical process to a totally diffused process reflected in self‐directed work teams. How can managers determine whether they are taking the right approach, or doing the right thing? Indeed, does the “right thing” refer to short‐term or long‐term results? In most organizations, there is no real process to explore the impact of decisions over either the short or long term. As this article explains, computer simulation models can be used to enhance an organization's decision‐making process and enable it to “see” the impact of its future choices over both the short and long term.
Conducting a readiness assessment: A foundation for solid teamwork
Authors: Recardo Ronald J.
Published: August 2012

One of the more surprising results of a survey on teams conducted by the Catalyst Consulting Group indicated that more than 70 percent of them are unsuccessful. One of the reasons for this low success rate is the lack of formal assessment to provide baseline data on the organization that can serve as a valuable input into the redesign process. This article discusses the objective of such a formal, or readiness, assessment, what to measure, how to collect the data, and how to feed the data back and use it as a first step in any work redesign effort.
Quality improvement and equal opportunity: Must they be at odds?
Authors: White Charles S. , Macomber James H.
Published: August 2012

Essential to any business, quality improvement typically requires stringent selection and training procedures for newly hired employees. But strengthening an organization's selection criteria can leave a firm open to charges of disparate impact and discrimination. In this article, the authors discuss the conflict between quality improvement and equal opportunity efforts, and offer strategies for helping organizations meet both their quality improvement goals and their equal opportunity responsibilities.
Supply chain concepts applied to organizational expense management
Authors: Harris Bill
Published: August 2012

Traditional organizational expense management, like traditional supply chain management, ignores so‐called pipeline inventory. For those who have ever played MIT's Beer Game, the problem is easy to recognize: people who are purchasing inventory don't have insight into what they've ordered but not yet received. They respond to current shortages by increased purchasing. After the pipeline delay passes, masses of inventory pour in. Then those purchasing inventory typically shut off further spending, to no further short‐term avail. Eventually the pipeline clears and the inventory excess turns into a shortage, at which time the cycle repeats. The correction is fairly simple: include the pipeline inventory in the calculation. Gaining that visibility is key to establishing a financial control system which responds stably to changes.
Cooperative advantage—A new measure of performance
Authors: Skrabec Quentin R.
Published: August 2012

The industrial paradigm of this century focused on competitive advantage, but a new framework has emerged in the post‐industrial environment—cooperative advantage. This new approach, which focuses on cooperative advantage and capabilities, features an alignment of business organizations that stresses joint success among groupings of enterprises. This article explains that the new competitive arena will be based on cooperation in supply chains, shared resources, corporate infrastructure, and government legislation.
Pipeline inventory: The missing factor in organizational expense management
Authors: Harris Bill
Published: August 2012

Traditional organizational expense management, like traditional supply chain management, typically ignores so‐called pipeline inventory. The result: inventory pile‐ups and erratic spending patterns. The correction is fairly simple: include the pipeline inventory in the calculation. Gaining that visibility is key to establishing a financial control system that responds stably to changes.
Building for success at karsten homes
Authors: Karsten Scott , Kossoff Leslie L.
Published: August 2012

Soon after Karsten Homes, a New Mexico manufactured home builder, began start‐up operations, its management realized that an extensive turnaround effort was going to be required to secure the company's future. Amazingly, a successful turnaround was achieved in just six months. Beginning with top management and including all personnel, it focused on fine‐tuning the organization's culture, management and operating structure, and developmental training. Part of the importance of this turnaround case study lies in its revelation that old and established organizational systems and concepts can affect a new enterprise, even though the old organization no longer exists.
Using competency assessments to support changing business goals
Authors: Barborek Susan , Brown Jeff
Published: August 2012

Organizations in the midst of pursuing a new business strategy often have trouble lining up employee performance and behaviors to support their new business goals. What can they do to better align people's skills to the jobs they do, or to transform the organizational culture? This article outlines how competency assessments can be a powerful transformational tool for companies to use as they change business strategies, undertake restructuring, or strive to align employee skill sets with emerging job requirements as part of process redesign efforts.
You can improve almost any process
Authors: Miller George J.
Published: August 2012

Improvement is the goal of every organization. But just how does an organization or one of its departments go about improving its processes? How can they make sure they're targeting the areas that will generate the most critical results? This article outlines a simple, effective approach to process improvement that can be applied to any business setting in any industry.
Loss ofmiR‐101expression promotes Wnt/β‐catenin signalling pathway activation and malignancy in colon cancer cells
Authors: Strillacci Antonio , Valerii Maria Chiara , Sansone Pasquale , Caggiano Cinzia , Sgromo Annamaria , Vittori Laura , Fiorentino Michelangelo , Poggioli Gilberto , Rizzello Fernando , Campieri Massimo , Spisni Enzo
Published: August 2012

Colorectal cancer (CRC) is the second leading cause of cancer‐related mortality in Western countries. Although the aberrant expression of severalmicroRNAs(oncomiRs) is associated withCRCprogression, the molecular mechanisms of this phenomenon are still under investigation. Here we show thatmiR‐101expression is differentially impaired inCRCspecimens, depending on tumour grade.miR‐101re‐expression suppresses cell growth in3D, hypoxic survival and invasive potential inCRCcells showing low levels ofmiR‐101. Additionally, we provide molecular evidence of a bidirectional regulatory mechanism betweenmiR‐101expression and importantCRCpro‐malignant features, such as inflammation, activation of the Wnt/β‐catenin signalling pathway and epithelial–mesenchymal transition (EMT). We then propose that up‐regulatedmiR‐101may function as a tumour suppressor inCRCand that its pharmacological restoration might hamper the aggressive behaviour ofCRCin vivo.MiR‐101expression may also represent a cancer biomarker forCRCdiagnosis and prognosis. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Flatness and microstructure of a light guide plate fabricated by microinjection molding
Authors: Lin Yun‐Ho , Huang Chiung‐Fang , Cheng Hsin‐Chung , Lin Yi , Lee Jeou‐Long , Shen Yung‐Kang
Published: August 2012

This study photo‐etches micropatterns on mold inserts and manufactures a light guide plate with microstructures using microinjection molding. The single parameter method is used to investigate flatness and replication with different process parameters for microinjection molding. Mold temperature is the most important factor for plate flatness and microstructure replication of a light guide plate fabricated by microinjection molding. Low mold temperature increases the flatness of light guide plates, whereas a high mold temperature improves height replication of the microstructure of light guide plates. Optimal mold temperature to maintain flatness and increase microstructure replication of light guide plates is 60°C. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
The investigation of novel non‐metallocene catalysts with phenoxy‐imine ligands for ethylene (co‐)polymerization
Authors: Zhang Xinli , Liu Zhi , Yi Jianjun , Huang Haibing , Dou Xiuli , Zhen Hongpeng , Huang Qigu , Gao Kejing , Zhang Mingge , Yang Wantai
Published: August 2012

Phthaldialdehyde and phthaldiketone were treated with substituted phenols of 2‐amino‐4‐methylphenol, 2‐amino‐5‐methylphenol and 2‐amino‐4‐t‐butylphenol, respectively, and then treated with transition metal halides of TiCl4, ZrCl4 and YCl3. A series of novel non‐metallocene catalysts (1–12) with phenoxy‐imine ligands was obtained. The structures and properties of the catalysts were characterized by 1H NMR and elemental analysis. The catalysts (1–12) were used to promote ethylene (co‐)polymerization after activation by methylaluminoxane. The effects of the structures and center atoms (Ti, Zr and Y) of these catalysts, polymerization temperature, Al/M (M = Ti, Zr and Y) molar ratio, concentration of the catalysts and solvents on the polymerization performance were investigated. The results showed that the catalysts were favorable for ethylene homopolymerization and copolymerization of ethylene with 1‐hexene. Catalyst 10 is most favorable for catalyzing ethylene homopolymerization and copolymerization of ethylene with 1‐hexene, with catalytic activity up to 2.93 × 106 gPE (mol Y)−1 h−1 for polyethylene (PE) and 2.96 × 106 gPE (mol Y)−1 h−1 for copolymerization of ethylene with 1‐hexene under the following conditions: polymerization temperature 50 °C, Al/Y molar ratio 300, concentration of catalyst 1.0 × 10−4 L−1 and toluene as solvent. The structures and properties of the polymers obtained were characterized by Fourier transform infrared spectroscopy, 13C NMR, wide‐angle X‐ray diffraction, gel permeation chromatography and DSC. The results indicated that the obtained PE catalyzed by 4 had the highest melting point of 134.8 °C and the highest weight‐average molecular weight of 7.48 × 105 g mol−1. The copolymer catalyzed by 4 had the highest incorporation of 1‐hexene, up to 5.26 mol%, into the copolymer chain. © 2012 Society of Chemical Industry
Ultrasound‐assisted synthesis of benzoxazine monomers: thermal and mechanical properties of polybenzoxazines
Authors: Vengatesan Muthukumaraswamy Rangaraj , Devaraju Subramani , Kannaiyan Dinakaran , Song Jang Kun , Alagar Muthukaruppan
Published: August 2012

A series of benzoxazine monomers (P‐aea2–P‐aea8) were prepared from appropriate aromatic diamines containing linear aliphatic ether chains with phenol and formaldehyde through the Mannich reaction under ultrasonication and conventional methods. Based on the reaction performance, the ultrasonication method has been found to be more facile and convenient for the synthesis of benzoxazine monomer than the conventional method. The synthesized monomers undergo curing at a lower temperature than that of conventional benzoxazine (Ba‐A) monomer as evidenced from differential scanning calorimetric analysis. The presence of an aliphatic ether core in the benzoxazine monomer aids in lowering the curing temperature, which seems to vary linearly with chain length. Thermally polymerized benzoxazine (poly(P‐aeas)) shows an enhanced tensile and flexural strength. Copyright © 2012 Society of Chemical Industry
Oxygen permeability, electron spin resonance, differential scanning calorimetry and positron annihilation lifetime spectroscopy studies of uniaxially deformed linear low‐density polyethylene film
Authors: Klepac Damir , Ščetar Mario , Kurek Mia , Mallon Peter E. , Luyt Adriaan S. , Galić Kata , Valić Srećko
Published: August 2012

Linear low‐density polyethylene (PE‐LLD) films were mechanically deformed at room temperature in both parallel and perpendicular directions to their initial orientation obtained during the manufacturing process. The degree of deformation ${\lambda}$, defined as ${\lambda} = l/l_{0}, l$ and l0 being the length of the deformed and relaxed samples, respectively, was varied from 1.0 to 2.0. Oxygen transport was investigated by a manometric method and the results were correlated with differential scanning calorimetry and positron annihilation lifetime spectroscopy measurements in order to investigate the contribution of various factors that influence the permeability of deformed PE‐LLD films. An electron spin resonance spin‐probe method was employed to determine the influence of uniaxial deformation on the chain segmental mobility in the amorphous phase. The results show that the deformation process reduces oxygen permeability and diffusion coefficients. It was found that the reduction is a combined effect of an increased crystallinity and reduced fractional free volume. The decrease of the chain segmental mobility with deformation plays an important role in the gas diffusion mechanism. © 2012 Society of Chemical Industry
Proteomic profiling of high glucose primed monocytes identifies cyclophilin A as a potential secretory marker of inflammation in type 2 diabetes
Authors: Ramachandran Surya , Venugopal Anila , K. Sathisha , G. Reshmi , Charles Sona , G. Divya , Chandran N. S. Pratap , Mullassari Ajit , Pillai M. Radhakrishna , Kartha C. C.
Published: August 2012

Hyperglycemia is widely recognized to be a potent stimulator of monocyte activity, which is a crucial event in the pathogenesis of atherosclerosis. We analyzed the monocyte proteome for potential markers that would enhance the ability to screen for early inflammatory status in Type 2 diabetes mellitus (T2DM), using proteomic technologies. Monocytic cells (THP‐1) were primed with high glucose (HG), their protein profiles were analyzed using 2DE and the downregulated differentially expressed spots were identified using MALDI TOF/MS. We selected five proteins that were secretory in function with the help of bioinformatic programs. A predominantly downregulated protein identified as cyclophilin A (sequence coverage 98%) was further validated by immunoblotting experiments. The cellular mRNA levels of cyclophilin A in various HG‐primed cells were studied using qRT‐PCR assays and it was observed to decrease in a dose‐dependent manner. LC‐ESI‐MS was used to identify this protein in the conditioned media of HG‐primed cells and confirmed by Western blotting as well as ELISA. Cyclophilin A was also detected in the plasma of patients with diabetes. We conclude that cyclophilin A is secreted by monocytes in response to HG. Given the paracrine and autocrine actions of cyclophilin A, the secreted immunophilin could be significant for progression of atherosclerosis in type 2 diabetes. Our study also provides evidence that analysis of monocyte secretome is a viable strategy for identifying candidate plasma markers in diabetes.
Trajectory of isoelectric focusing from gels to capillaries to immobilized gradients in capillaries
Authors: Koshel Brooke M. , Wirth Mary J.
Published: August 2012

This review presents the need for replacing gels in 2D separations for proteomics, where speed, high‐throughput, and the ability to characterize trace level proteins or small samples are the current desires. The theme of the review is isoelectric focusing, which is a valuable tool because it pre‐concentrates proteins in addition to separating with high peak capacity. The review traces the technological progress from gel IEF to CIEF to packed capillaries with immobilized gradients for CIEF. Multiple capillary techniques are progressing toward meeting the current desires, providing extremely high sensitivity with regard to concentration and to small samples, integrated automation, and high peak capacity from multiple dimensions of separation. Capillaries with immobilized pH gradients for CIEF are emerging, which will alleviate interference from ampholytes and improve reproducibility in separation times when this valuable technique can be used as one of the dimensions.
Tryptic peptide screening for primary immunodeficiency disease by LC/MS‐MS
Authors: Kerfoot Sandra A. , Jung Sunhee , Golob Karin , Torgerson Troy R. , Hahn Si Houn
Published: August 2012

Purpose

Early diagnosis of primary immunodeficiency disorders (PIDDs) is critical for maximizing patient survival and clinical outcomes. Consequently, there is significant interest in developing broad‐based, high‐throughput, screening approaches capable of utilizing small blood volumes to identify patients with PIDD.

Experimental design

We developed a novel proteomic screening approach using tandem mass spectrometry to simultaneously identify specific signature peptides derived from the transmembrane protein cluster of differentiation 3 (CD3)ɛ and the intracellular proteins Wiskott‐Aldrich syndrome protein (WASP) and Bruton's tyrosine kinase (BTK) as markers of three life‐threatening PIDDs; severe combined immunodeficiency, Wiskott‐Aldrich syndrome, and X‐linked Agammaglobulinemia. Signature peptides were analyzed by LC/MS‐MS in proteolytically digested lysates from cell lines and white blood cells (WBCs). The amount of each peptide was determined by the ratio of the signature peptide peak area to that of a known amount of labeled standard peptide. Peptide concentrations were normalized to actin.

Results

We show that signature peptides from CD3ɛ, WASP, and BTK were readily detected in proteolytically digested cell lysate and their absence could correctly identify PIDD patients.

Conclusions and clinical relevance

This proof of concept study demonstrates the applicability of this approach to screen for PIDD and raises the possibility that it could be further multiplexed to identify additional PIDDs and potentially other disorders.
Stepwise isolation of human peripheral erythrocytes, T lymphocytes, and monocytes for blood cell proteomics
Authors: Brosseron Frederic , May Caroline , Schoenebeck Bodo , Tippler Bettina , Woitalla Dirk , Kauth Marion , Brockmann Kathrin , Meyer Helmut E. , Berg Daniela , Bufe Albrecht , Marcus Katrin
Published: August 2012

Purpose

Density gradient centrifugation and magnetic‐ or fluorescence‐activated cell sorting are common and robust techniques for the isolation of different types of blood cells. In this article, we give detailed description of a stepwise application of these methods as one isolation strategy for enrichment of different cell types from one blood sample.

Experimental design

The workflow targeted erythrocytes, monocytes, and T lymphocytes. Pancoll® density gradient centrifugation was used together with subsequent MACS™ isolation. Purity of monocytes and T lymphocytes was controlled by fluorescence‐activated cell sorting analysis, and cells were used for carrier‐ampholine‐based 2D‐PAGE to confirm compatibility of the procedure to standard proteomic applications.

Results

Gradient centrifugation resulted in an average of 125 μL of packed erythrocytes per milliliter blood. MACS™ sorting reached purities of 90 ± 2% (monocytes) and 93 ± 2% (T lymphocytes), with an average yield of 12 × 104 monocytes or T lymphocytes. 2D‐PAGE of isolated cells showed well‐separated spot patterns.

Conclusions and clinical relevance

A combined isolation holds substantial advantages especially in clinical studies, as it allows for the comparison of findings not only between individuals, but also between different cell types derived from one donor. Our approach ensured high reproducibility, yields, and purities of cells as required for reliable proteome analysis.
Role of the ribosomal protein L27 revealed by single‐molecule FRET study
Authors: Wang Yuhong , Xiao Ming
Published: August 2012

The ribosome is a ribozyme. However, in bacterial ribosomes, the N‐terminus of L27 is located within the peptidyl transfer center. The roles of this protein in real time remain unclear. We present single‐molecule fluorescence resonance energy transfer (FRET) studies of tRNA dynamics at the peptidyl transfer center in ribosomes containing either wild type (WT) L27, or L27 mutants with A2H3, A2H3K4 or nine N‐terminal residues removed. Removing L27's first three N‐terminal residues or mutating a single residue, K4, reduces the formation of a stable peptidyl tRNA after translocation. These results imply that L27 stabilizes the peptidyl tRNA and residue K4 contributes significantly to the stabilization.
TectoRNP: self‐assembling RNAs with peptide recognition motifs as templates for chemical peptide ligation
Authors: Yamashita Kohei , Tanaka Takahiro , Furuta Hiroyuki , Ikawa Yoshiya
Published: August 2012

TectoRNA, an artificial RNA with self‐assembling ability, has been employed as a structural platform for RNA nanotechnology and RNA synthetic biology. In this study, tectoRNA was applied as a specific template for chemical peptide ligation. On the basis of a self‐assembling tectoRNA, we designed and constructed a template RNA that facilitates peptide ligation depending on controlled dimer formation. Two RNA‐binding peptides were recognized by two peptide‐binding RNA motifs embedded in the template RNA, and chemical ligation was promoted because of the entropic effect of Mg2+‐dependent dimerization. In a series of biochemical analyses, we determined the relationship between the structures of the tectoRNA‐based templates and the extent of acceleration in peptide ligation. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
DFT study of the physicochemical characteristics and spectral behavior of new 8‐substituted 1,3,7‐trimethylxanthines
Authors: Stanchev Stancho , Mitkov Javor , Georgieva Maya , Zlatkov Alexander
Published: August 2012

Nine biologically active theophylline derivatives were investigated using quantum chemical methods (density functional theory level). All calculations were performed at B3LYP/6‐31G** level of theory. The electrostatic potential charges, highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) gap, dipole moment, vibration frequencies, and electronic spectra were calculated. Log P was determined by Ghose‐Crippen method. All of the compounds under study are polar and negatively charged, which is necessary for their interaction with the receptors/enzymes. Majority of the compounds are lipophilic and they can easily diffuse through the cell membrane. The observed differences between the calculated and the experimental vibration frequencies in the Fourier Transform Infrared Spectroscopy (FTIR) spectra are established to be mainly in NH and OH bands, due to hydrogen bonds formation. The discrepancies between theoretical and experimental electronic spectra may be due to vibration effects and H‐bonding with the solvent molecules. The obtained results show that this type of spectrum is formed mainly by the xanthine fragment of the molecule, especially in the fingerprint region. All calculated properties could be useful for future qualitative‐structure activity relationship (QSAR) analysis. © 2012 Wiley Periodicals, Inc.
Effect of cluster expansion on photoionization of iron pentacarbonyl doped inert gas clusters under gigawatt intensity laser irradiation
Authors: Badani Purav M. , Das Soumitra , Sharma Pramod , Vatsa Rajesh K.
Published: August 2012

RATIONALE

The aim of the investigation was to understand the variation in ionization dynamics of inert gas clusters upon doping with species with lower ionization energy than the inert gas constituent. It was postulated that the use of dopant species having lower ionization energy would lead to facile ionization of doped inert gas clusters, resulting in enhancement of the charge state of atomic ions compared with those obtained for pure inert gas clusters.

METHODS

Inert gas clusters (Arn, Krn or Xen) doped with iron pentacarbonyl were generated by supersonic expansion and subjected to gigawatt intensity laser pulses (266, 355, 532 and 1064 nm wavelengths) obtained from a nanosecond Nd:YAG laser. The ions generated upon laser‐cluster interaction were characterized using a time‐of‐flight mass spectrometer.

RESULTS

Upon interaction of the laser with the doped inert gas clusters, the charge states of the atomic ions were found to increase with the laser wavelength. However, the highest observed charge states were found to be lower for doped inert gas clusters than for pure inert gas clusters, at all laser wavelengths.

CONCLUSIONS

Wavelength‐dependent generation of multiply charged atomic ions has been explained based on the three stage model, i.e. multiphoton ionization ignited‐inverse bremsstrahlung heating, and electron ionization. This model explains enhancement in the charge state of atomic ions with increasing wavelength based on inverse bremsstrahlung heating of the inner ionized electron, which is a more efficient process at longer wavelengths. Inefficient coupling of laser energy in the case of doped inert gas clusters compared with pure inert gas clusters has been rationalized on the basis of accelerated disintegration of the cluster due to facile initial ionization of dopant molecules having low ionization energy. The results suggest that a longer laser wavelength and a slower rate of cluster expansion facilitate the efficient transfer of optical energy into cluster systems. Copyright © 2012 John Wiley & Sons, Ltd.
Assessing the rate and timing of leaf wax regeneration in Fraxinus americana using stable hydrogen isotope labeling
Authors: Gao Li , Tsai Yih‐Jin , Huang Yongsong
Published: August 2012

RATIONALE

Understanding leaf wax regeneration and recycling is crucial for plant physiology and paleoclimate studies. However, our recent isotope labeling experiments on a grass species (Phleum pratense) yielded different conclusions from published data on a tree species (Populus trichocarpa), with the former showing rapid regeneration and the latter little regeneration in mature leaves. It is therefore important to determine if the discrepancies in published results were due to differing dynamics of leaf wax regeneration and/or caveats in experimental methods.

METHODS

Leaves from a native New England tree species (Fraxinus americana) were collected at 1 to 3 h intervals over a 2‐day experimental period, and, subsequently, the leaf wax δ2H isotopic ratios were measured using gas chromatography/isotope ratio mass spectrometry.

RESULTS

It was necessary to irrigate the tree using water with significantly higher δ2H values than that used for the grass in order to obtain readily measurable isotopic responses over diurnal cycles. In addition, diurnal leaf wax regeneration in Fraxinus americana was delayed by 1–4 h relative to Phleum pratense, suggesting that the latter produced leaf waxes from more recently photosynthesized substrates.

CONCLUSIONS

The isotopic inertia in Fraxinus americana was due to lower leaf wax regeneration rates than in Phleum pratense by one to two orders of magnitude. The difference in the timing of leaf wax biosynthesis might partially account for the observed leaf wax hydrogen isotopic difference between trees and grasses. Copyright © 2012 John Wiley & Sons, Ltd.
Dual observer‐based compensators for nonlinear systems
Authors: Deutscher Joachim
Published: August 2012

In this article, the concept of dual observer‐based compensators is extended from linear to nonlinear systems. It is shown that a dual observer‐based compensator achieves stabilization by rendering an invariant manifold attractive in which desired dynamics can be assigned. The design of these compensators for nonlinear systems is considerably simple if a flat output of the system to be controlled is known which is illustrated by means of a simple example. Copyright © 2012 John Wiley & Sons, Ltd.