bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural characterization by nuclear magnetic resonance of the impact of phosphorylation in the proline‐rich region of the disordered Tau protein
Authors: Sibille Nathalie , Huvent Isabelle , Fauquant Caroline , Verdegem Dries , Amniai Laziza , Leroy Arnaud , Wieruszeski Jean‐Michel , Lippens Guy , Landrieu Isabelle
Published: September 2011

Phosphorylation of the neuronal Tau protein is implicated in both the regulation of its physiological function of microtubule stabilization and its pathological propensity to aggregate into the fibers that characterize Alzheimer's diseased neurons. However, how specific phosphorylation events influence both aspects of Tau biology remains largely unknown. In this study, we address the structural impact of phosphorylation of the Tau protein by Nuclear Magnetic Resonance (NMR) spectroscopy on a functional fragment of Tau (Tau[Ser208–Ser324] = TauF4). TauF4 was phosphorylated by the proline‐directed CDK2/CycA3 kinase on Thr231 (generating the AT180 epitope), Ser235, and equally on Thr212 and Thr217 in the Proline‐rich region (Tau[Ser208‐Gln244] or PRR). These modifications strongly decrease the capacity of TauF4 to polymerize tubulin into microtubules. While all the NMR parameters are consistent with a globally disordered Tau protein fragment, local clusters of structuration can be defined. The most salient result of our NMR analysis is that phosphorylation in the PRR stabilizes a short α‐helix that runs from pSer235 till the very beginning of the microtubule‐binding region (Tau[Thr245‐Ser324] or MTBR of TauF4). Phosphorylation of Thr231/Ser235 creates a N‐cap with helix stabilizing role while phosphorylation of Thr212/Thr217 does not induce modification of the local transient secondary structure, showing that the stabilizing effect is sequence specific. Using paramagnetic relaxation experiments, we additionally show a transient interaction between the PRR and the MTBR, observed in both TauF4 and phospho‐TauF4. Proteins 2012. © 2011 Wiley Periodicals, Inc.
Nanochemical reactions by laser annealing of ferrocene filled single‐walled carbon nanotubes
Authors: Briones Antonio , Liu Xianjie , Kramberger Christian , Saito Takeshi , Pichler Thomas
Published: September 2011

Thermal annealing of FeCp2 filled SWCNT yields DWCNT via a catalytic reaction. The annealing time and temperature allow controlling the doping level. We present an in situ experimental approach to study the dynamics of the transformation of FeCp2 filled SWCNT to doped DWCNT. A frequency doubled Nd/YAG laser was used to anneal the samples and a He–Ne laser and a tunable Argon–Krypton laser were used to measure the Raman spectrum with different wavelengths. Samples were annealed in high vacuum, and Raman spectra of the transition to DWCNT were monitored. The observed inner tube mean diameters at 633 nm are 1.00, 0.71, and 0.51 nm for ferrocene filled eDIPS, laser ablation and HiPco SWCNT, respectively.

magnified image

Raman spectra of a FeCp2@SWCNT and a DWCNT.
HPLC Fingerprint of a Flower Extract of Tilia × viridis and Correlation with Antiproliferative and Antioxidant Activity
Authors: Marrassini C. , Anesini C. , Ferraro G.
Published: September 2011

Tilia species have been used in Europe and in America to treat anxiety and also for the treatment of colds, influenza, bronchitis, fever and inflammation. Tilia × viridis is a Tilia species distributed widely in Buenos Aires, Argentina. The flavonoids present in Tilia species have antioxidant properties, acting as reactive oxygen species (ROS) scavengers, principally on hydrogen peroxide (H2O2) and the superoxide anion (O2.‐), which are involved in many diseases, including cancer. The aim of this study was to determine the phytochemical pattern of the ethanol extract of Tilia × viridis, principally the flavonoid content, and to evaluate the antiproliferative effects on both normal and tumoral cells, and the antioxidant activity in relation to H2O2 modulation. The extract was found to present a selective antiproliferative activity on a lymphoma cell line and this was related to free radical scavenging activity. In addition, one of its main compounds, rutin, showed antioxidant effects related to peroxidase activity. T. × viridis may therefore be a source of antioxidant compounds that contribute to a selective antiproliferative action on tumoral cells, acting by modulation of H2O2 levels. Copyright © 2011 John Wiley & Sons, Ltd.
Security enhancement of the communication‐efficient AUTHMAC_DH protocols
Authors: Lv Chao , Ma Maode , Li Hui , Ma Jianfeng , Niu Ben
Published: September 2011

Authentication and key distribution (AKD) protocols have become more important in the design of communication systems. The design criteria of the AKD protocols include the scalability, the communication efficiency, the computational efficiency, and the robustness of security. In this paper, we first analyze the vulnerability of an AKD protocol under the off‐line guessing attack. Then, we propose an enhanced AKD protocol to overcome the vulnerability. Security analysis and formal verification by using AVISPA toolkit show that the proposed protocol can keep all the previous properties and is secure against the off‐line guessing attack. Copyright © 2011 John Wiley & Sons, Ltd.
The perils of high‐growth markets
Authors: Aaker David A. , Day George S.
Published: September 2011

The conventional wisdom that businesses should invest in growth markets is based upon the assumptions that, in the early phase of a growth market, share gains are easier and worth more, the experience curve will lead to advantage, price pressure will be low, needed access to the technology will result and future entries will be deterred. These assumptions are examined and six major types of growth market risks are discussed. Finally, conditions which should be present if an early entry into a growth market is attempted are identified.
The relationship of strategic planning to financial performance
Authors: Rhyne Lawrence C.
Published: September 2011

The relationship between financial performance and characteristics of corporate planning systems was investigated/Planning systems that combined an external focus with a long‐term perspective were found to be associated with superior 10‐year total return to stockholders. A lagged relationship between such systems and 4‐year average annual returns to investors also was identified.
The economic dynamics of work
Authors: Haley Michael
Published: September 2011

Only by developing management systems based on appropriate standards can a business successfully learn how to improve the technology of work. As a result, a new economics of work is created where the evolution of large organizations makes economic sense. But economies of scale no longer require rigid mass production of a limited product line. Flexibility can be introduced to produce product diversity without losing the efficiencies of standardization. Thus manufacturing can operate more flexibly like a service by learning to apply industrial robots and other smart machines. Service businesses can also learn how to manage more systematically by designing standard menus of operations.
Using simulated mergers to evaluate corporate diversification strategies
Authors: Silhan Peter A. , Thomas Howard
Published: September 2011

This study suggests that simulated mergers can be used to help evaluate the effects of diversification on corporate performance. The results, which are consistent with a risk‐reduction motive for conglomerate diversification, imply that conglomerate strategies focused on fewer and larger units may be advantageous in terms of certain measures of risk and return. Forecast error is used here to measure strategic risk, and return on equity is used to measure return.
Matching vertical integration strategies to competitive conditions
Authors: Harrigan Kathryn Rudie
Published: September 2011

This paper contrasts the vertical integration strategies of 192 firms in the presence of diverse environmental and strategic forces to suggest how successful uses of vertical integration differ from less successful ones. Briefly, firms which did not use vertical integration as effectively transferred more goods and services internally, and they did so more often under adverse industry conditions. A frequent error was to undertake more integrated activities in‐house and engage in longer chains of processing from ultra‐raw materials to finished goods. Ironically, many of the vertically integrated firms that suffered adversity possessed the bargaining power needed to contract advantageously for goods or services, but accepted an overly risky ownership position unnecessarily by producing them, instead.
The path dependence of organizational reputation: how social judgment influences assessments of capability and character
Authors: Mishina Yuri , Block Emily S. , Mannor Michael J.
Published: September 2011

Drawing upon theory on social judgments and impression formation from social psychology, this paper explores the socio‐cognitive processes that shape the formation of favorable and unfavorable organizational reputations. Specifically, we suggest that stakeholders make distinctions between an organization's capabilities and its character. We explain the nature and function of each and articulate the manner in which judgment heuristics and biases manifest in the development of capability and character reputations. In doing so, this research explores both the positive and negative sides of organizational reputation by examining the manner in which different types of reputations are built or damaged, and how these processes influence the ability of managers to enhance and protect these reputations. Copyright © 2011 John Wiley & Sons, Ltd.
Wrinkled Liquid‐Crystalline Microparticle‐Enhanced Photoresponse of PDLC‐Like Films by Coupling with Mechanical Stretching
Authors: Yu Haifeng , Dong Chong , Zhou WeiMin , Kobayashi Takaomi , Yang Huai
Published: September 2011

Photoresponsive behaviors are studied in hybrid liquid‐crystalline (LC) films prepared with light‐responsive LC polymer microparticles as dopants using photoinert polymers as a host material. Upon mechanical stretching, both topological shape change and mesogenic alignment occur in the LC polymer microparticles, enabling the polymer‐dispersed LC (PDLC)‐like films to bend toward a light source upon UV irradiation. The rough morphologies of the hydrophobic LC microparticles enhance their interactions with hydrophilic polymer substrates. The bilayer‐like structures of the hybrid film formed in the fabrication processes are responsible for the photomechanical behavior, which is reversibly controlled by combing light irradiation with the stretching processes.
Supporting business process analysis via data warehousing
Authors: Sturm Arnon
Published: September 2011

Today, business processes serve as the backbone of organizations. As a result, IT frameworks for managing business processes are gaining in popularity. The classical life cycle implemented in these frameworks consists of four stages: process specification, process implementation, process execution and monitoring, and process analysis. The relationships between the stages are usually loosely defined, and there is a need for means to synchronize these stages, in light of the frequent changes in and the need to maintain the entire business process life cycle. In this paper, we propose a method for constructing data warehouse schemata from business process specifications to facilitate the off‐line analysis of the business process execution. We define the relationships between the business process specification stage and the analysis stages, with the aim to facilitate and to identify potential improvements by querying the business process performance. Copyright © 2011 John Wiley & Sons, Ltd.
Efficiently and transparently automating scalable on‐demand activation and deactivation of services with the activator pattern
Authors: Stal Michael , Schmidt Douglas C. , Otte William R.
Published: September 2011

Computing systems are increasingly designed as a collection of interacting services that constitute a set of functionality offered by a service provider or server to its clients. Many service‐oriented computing systems have constraints on the resources they allocate and manage. In these systems, certain types of services should consume resources only when they are accessed by clients, and clients should be shielded from where services are located, how they are deployed, and how their lifecycle is managed. The activator pattern provides an effective means to efficiently and transparently automate scalable on‐demand activation and deactivation of services accessed by many clients. This paper motivates the need for the activator pattern, describes the structure and dynamics of canonical implementations of the pattern, and examines the benefits and liabilities of applying this pattern to services in resource‐constrained computing systems. Copyright © 2011 John Wiley & Sons, Ltd.
Towards design pattern definition language
Authors: Khwaja Salman , Alshayeb Mohammad
Published: September 2011

Design patterns are rapidly gaining acceptance in the software community not only as reusable constructs for software development but also for the documentation of the software architectural design. Most of the existing design pattern languages describe design patterns using a combination of a natural language, UML‐style diagrams and complex mathematical or logic based formalisms, which makes them hard for programmers to understand. In this paper we propose a design pattern definition language (DPDL) based on XML which can be used for sharing design patterns’ implementation details among developers. DPDL is easy to understand and use. It provides unambiguous description of the patterns and is extensible. DPDL also has the flexibility of defining design patterns in a generic term to be used as templates. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of structural characteristics of modified waxy corn starches on rheological properties, film‐forming solutions, and on water vapor permeability, solubility, and opacity of films
Authors: Pérez‐Gallardo Alfonso , Bello‐Pérez Luis A. , García‐Almendárez Blanca , Montejano‐Gaitán Gerardo , Barbosa‐Cánovas Gustavo , Regalado Carlos
Published: September 2011

Waxy corn starch (amylopectin) and three of its chemical derivatives: acetylated cross‐linked (ACLS), oxidized (OS), and octenyl‐succinylated (OSA), were used together with additives such as Tween 80, sorbitol, and beeswax suspension or safflower oil to test their effect on film‐forming solutions (FFS) and films. The objectives of this study were the starch structure characterization, and its correlation with rheological properties of FFS and solubility, opacity, and water vapor permeability (WVP) of the produced films. Analysis of starch structure, rheological characterization, and films micrographs revealed that the starches contained predominantly low MW amylopectin molecules and film properties depended on their ability to reorganize. Additionally, the interaction among groups introduced in modified starches or with additive molecules can hinder or promote starch reorganization, resulting in films with increased or reduced WVP, solubility and transparency properties. Films were obtained by casting and showed a thickness less than 41 µm. Films prepared with OS and beeswax exhibited the best reorganizing capacity of FFS, resulting in less soluble (30.0 ± 1.6%), highly transparent (23.2 ± 3.3 UA × nm) and less permeable films (0.485 ± 0.016 g · mm · m−2 · h−1 · kPa−1). On the other hand, ACLS showed an opposite trend which was attributed to a more open film structure. These results contribute to understand the molecular interactions of waxy starch molecules in FFS which may be useful to design tailored coatings.
Preoperative assessment of endometrial carcinoma by three‐dimensional power Doppler angiography
Authors: Saarelainen S. K. , Vuento M. H. , Kirkinen P. , Mäenpää J. U.
Published: September 2011

Objective

Preoperative evaluation of the depth of myometrial invasion in endometrial carcinoma is challenging. The objective of this study was to evaluate the usefulness of three‐dimensional power Doppler angiography (3D‐PDA) in this setting.

Methods

Sonographic and histological data on 100 consecutive cases of endometrial carcinoma were analyzed. The endometrial and myometrial vascular indices VI (vascularization index), FI (flow index) and VFI (vascularization flow index) were calculated by 3D‐PDA. The results were compared with a complete surgical staging.

Results

The mean ( ± SD) age of patients was 67.1 ± 8.8 (range, 33–87) years. Forty‐six patients had deep (≥ 50%) myometrial invasion. Eight patients had metastases, seven of them with deep invasion. Three patients were found to have carcinomas of non‐uterine origin on histology, and these were excluded from further statistical analysis. The median endometrial and myometrial vascular indices were higher in the group with deep invasion than in the group without. Following multivariable analysis of the indices only the endometrial FI was independently associated with deep invasion (OR, 1.061; 95% CI, 1.023–1.099; P = 0.001). However, a greater endometrial volume was also an independent predictor of deep invasion (OR, 1.109; 95% CI, 1.011–1.215; P = 0.028).

Conclusion

Our study suggests that endometrial and, to a lesser degree, myometrial vascular indices and endometrial volume correlate with the depth of myometrial invasion in endometrial carcinoma. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Part‐of‐speech tagging
Authors: Martinez Angel R.
Published: September 2011

Presented here is a brief state‐of‐the‐art account on part‐of‐speech (POS) tagging. POS tagging is an essential preprocessing task for many natural language processing goals and applications. Some POS tagging approaches make use of annotated corpora to train computational models to perform the task with minimal human intervention. Rule‐based and stochastic methods have been successful, attaining accuracies of 96–97%. Representative approaches of these two methodologies are discussed. WIREs Comp Stat 2012, 4:107–113. doi: 10.1002/wics.195

This article is categorized under:

Software for Computational Statistics > Artificial Intelligence and Expert Systems

Data: Types and Structure > Text Data

Statistical Learning and Exploratory Methods of the Data Sciences > Text Mining
Robust clustering
Authors: Banerjee Amit , Davé Rajesh N.
Published: September 2011

Historical and recent developments in the field of robust clustering and their applications are reviewed. The discussion focuses on different strategies that have been developed to reduce the sensitivity of clustering methods to outliers in data, while pointing out the importance of the need for both efficient partitioning and simultaneous robust model fitting. Although all clustering methods and algorithms have good partitioning capabilities when data are clean and free of outliers, they break down in the presence of outliers in the data. This is because classical development in the field of clustering has focused on such assumptions that data is free of noise and the data are well distributed, Robust model fitting, while retaining the partitioning power, involves the development of methods and algorithms that reject these classical assumptions either by explicitly incorporating robust statistical methods (often regression based) or by recasting the clustering problem in a way that does so implicitly. In this review, the robust model fitting aspect is identified in pertinent methodological and algorithmic advances and tied to related developments in robust statistics wherever possible. The paper also includes representative samples of various applications of robust clustering methods to both synthetic and real‐world datasets. © 2011 Wiley Periodicals, Inc.

This article is categorized under:

Algorithmic Development > Structure Discovery

Technologies > Structure Discovery and Clustering
Calcium phosphate‐based composite nanoparticles in bioimaging and therapeutic delivery applications
Authors: Tabaković Amra , Kester Mark , Adair James H.
Published: September 2011

Bioimaging and therapeutic delivery applications are areas of biomedicine where nanoparticles have had significant impact, but the use of a nanomaterial in these applications can be limited by its physicochemical properties. Calcium phosphate‐based composite nanoparticles are nontoxic and biodegradable, and are therefore considered attractive candidates for bioimaging and therapeutic drug delivery applications. Also, the pH‐dependent solubility profiles of calcium phosphate materials make this class of nanoparticles especially useful for in vitro and in vivo delivery of dyes, oligonucleotides, and drugs. In this article, we discuss how calcium phosphate‐based composite nanoparticles fulfill some of the requirements typically made for nanoparticles in biomedical applications. We also highlight recent studies in bioimaging and therapeutic delivery applications focusing on how these studies have addressed some of the challenges associated with using these nanoparticles in bioimaging and delivery of therapeutics. WIREs Nanomed Nanobiotechnol 2012, 4:96–112. doi: 10.1002/wnan.163

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Emerging Technologies

Diagnostic Tools > In Vitro Nanoparticle-Based Sensing

Diagnostic Tools > In Vivo Nanodiagnostics and Imaging

Implantable Materials and Surgical Technologies > Nanomaterials and Implants
A New Mixed‐Valent High Nuclearity Polyoxovanadate Cluster Based on the {V18O42} Archetype
Authors: Wutkowski Adam , Niefind Felix , Näther Christian , Bensch Wolfgang
Published: September 2011

The compound (enH2)6[HV16IVV2VO42(Cl)]·Cl2·2H2O (en = 1,2‐diaminoethane) (1), was synthesized under solvothermal conditions employing the amine as reducing agent. Compound 1 crystallizes in the orthorhombic space group Pbcn with a = 13.3343(7), b = 22.3697(3), c = 19.8012(11) Å, V = 5906.4(5) Å3, Z = 4. The central structural motif is a polyoxovanadate anion [HV18O42(Cl)]10– being composed of 18 VO5 square pyramids. The cluster shell contains a (VO5)8 ring in the vertical plane and two (VO5)5 pentagons above and below the ring which are twisted by 45° against each other.Bond valence sum analysis indicates a mixture of VIV/VV atoms with a ratio of 16:2, which is further supported by redox titration. An arrangement of these clusters within the (001) plane leads to the formation of channels hosting the protonated amine molecules, the Cl– anions and water molecules which are joined by an extended hydrogen bonding network. TG‐MS investigation shows a thermal decomposition reaction in at least three steps. The optical band gap was determined as 2.5 eV.
A Geometric Analysis of When Fixed Weighting Schemes Will Outperform Ordinary Least Squares
Authors: Davis-Stober Clintin P.
Published: September 2011

Many researchers have demonstrated that fixed, exogenously chosen weights can be useful alternatives to Ordinary Least Squares (OLS) estimation within the linear model (e.g., Dawes, Am. Psychol. 34:571–582, 1979; Einhorn & Hogarth, Org. Behav. Human Perform. 13:171–192, 1975; Wainer, Psychol. Bull. 83:213-217, 1976). Generalizing the approach of Davis-Stober, Dana, and Budescu (Psychometrika 75:521–541, 2010b), I present an analytic method to determine when a choice of fixed weights will incur less mean squared error than OLS as a function of sample size, error variance, and model predictability. Geometrically, I solve for the region of population β that favors a choice of fixed weights over OLS. I derive closed-form upper and lower bounds on the volume of this region, giving tight bounds on the proportion of population β favoring a choice of fixed weights. I illustrate this methodology with several examples and provide a MATLAB© (The MathWorks, Matlab software, version 2009b, 2010) programming implementation of the major results.
Shock trains on a planar beach
Authors: Antuono Matteo
Published: September 2011

Following on from the author’s previous work, the propagation of trains of shock waves on a planar beach is studied in the framework of the nonlinear shallow water equations. The analysis is based on the use of a quasi-analytical solution valid for a shock wave which is fed by a constant Riemann invariant. The asymptotic behaviour of a train of such shock waves is inspected and novel approximate analytical solutions are provided. These are useful both for representing fundamental physical scenarios (e.g. propagation of saw-tooth spilling breakers in the surf zone) and for benchmarking wave-resolving and wave-averaged theoretical/numerical solutions. Finally, a study of the energy dissipation induced by the shock train is provided.
Vitamin D status and pain: analysis from the Health Survey for England among English adults aged 65 years and over
Authors: Hirani Vasant
Published: September 2011

Poor vitamin D status is common in older people and results in osteoporosis; osteomalacia is associated with a wide range of non-communicable diseases and has potential effects on poor health outcomes. Pain is also common in older people and can be substantially disabling. The aim of the present analysis is to investigate associations between serum 25-hydroxy vitamin D (25(OH)D) and self-reported current symptoms of pain in a cross-sectional, nationally representative sample of 2070 adults aged ≥ 65 years living in the community in England in 2005. Measurements included serum 25(OH)D, pain status and covariates, namely, age, sex, social class, season of examination, use of vitamin supplements and physical health status. Results show that the symptoms of moderate/extreme pain (present in 53 % of the sample) were associated with poor vitamin D status, independent of other covariates. Particular advantages of the present study were the presence of directly measured vitamin D levels and a large and nationally representative sample. Poor vitamin D status is common and an associated risk factor for pain in older people living in northern latitudes. The direction of causation cannot be inferred from a cross-sectional study and further prospective research is required to clarify this. Regardless of the direction of causation, the relationship is potentially of high public health importance because of the adverse impact of both states on well-being. It is important that older people in pain are screened for vitamin D status and provided with appropriate interventions.
Multiobjective optimization of parallel kinematic mechanisms by the genetic algorithms
Authors: Kelaiaia Ridha , Company Olivier , Zaatri Abdelouahab
Published: September 2011

It is well known that Parallel Kinematic Mechanisms (PKMs) have an intrinsic dynamic potential (very high speed and acceleration) with high precision and high stiffness. Nevertheless, the choice of optimal dimensions that provide the best performances remains a difficult task, since performances strongly depend on dimensions. On the other hand, there are many criteria of performance that must be taken into account for dimensional synthesis, and which are sometimes antagonist. This paper presents an approach of multiobjective optimization for PKMs that takes into account several criteria of performance simultaneously that have a direct impact on the dimensional synthesis of PKMs. We first present some criteria of performance such as the workspace, transmission speeds, stiffness, dexterity, precision, as well as dynamic dexterity. Secondly, we present the problem of dimensional synthesis, which will be defined as a multiobjective optimization problem. The method of genetic algorithms is used to solve this type of multiobjective optimization problem by means of NSGA-II and SPEA-II algorithms. Finally, based on a linear Delta architecture, we present an illustrative application of this methodology to a 3-axis machine tool in the context of manufacturing of automotive parts.
The influence of microhabitat, moisture and diet on stable-hydrogen isotope variation in a Neotropical avian food web
Authors: Fraser Kevin C. , McKinnon Emily A. , Diamond Antony W. , Chavarría Liliana
Published: September 2011

The application of stable-hydrogen isotope (δD) measurements to the study of animal movement, resource use and physiology depends on understanding factors driving variation in δD in animal tissues. The source of micro-scale variation in δD is poorly known, yet understanding micro-scale patterns of δD could shed light on important ecological processes and improve our abilities to track animal movements. Using linear and additive models, we explored the influence of micro-scale habitat use, moisture and diet on tissue δD values of Nicaraguan cloud-forest birds. Using mist nets, we captured 211 individuals of 22 resident Neotropical species at 500–1390 m asl and collected feather and claw samples. Based on three years of data from year-round sampling, our results suggest that microhabitat, seasonal shifts in moisture δD, and diet all influence bird tissue δD values. Our model results reveal a previously undescribed microgeographical effect on δD, where foraging level (understorey versus overstorey) and foraging location (forest interior versus adjacent coffee plantation) were significant predictors of δD values in bird claws and feathers. Mean claw and feather δD values among species varied from −83‰ to −19‰. Top models for claws and feathers explained 57% and 52% of variation in δD respectively. Direct comparisons of understorey (mean ± SD of −30‰ ± 15‰) versus overstorey (−50‰ ± 15‰) claw values suggest that δD may be useful in tracking vertical, micro-scale movement. Higher δD values in forest understorey birds reveal a heavy reliance upon recycled, fog moisture. Fragmentation and climate change may result in increasingly desiccated cloud forest that may exert a more negative influence on the food webs of understorey species that seem to be supported by recycled sources of moisture in the dry season.
A new case of neotropical monodominant forest:Spirotropis longifolia(Leguminosae-Papilionoideae) in French Guiana
Authors: Fonty Émile , Molino Jean-François , Prévost Marie-Françoise , Sabatier Daniel
Published: September 2011

The main interest in studying monodominant forests in the tropics (i.e. single-dominant forestsensuRichards 1996 and Connell & Lowman 1989) is that processes leading to monodominance may highlight mechanisms controlling species diversity (Hartet al. 1989). Among the various cases of monodominant forest (Hart 1990), the most intriguing are the rare ones that stand in contact with a considerably more diverse forest, without apparent environmental boundaries, and for many generations (i.e. type IsensuConnell & Lowman 1989). Rather than a single mechanism, it is likely that this type of monodominance results from a suite of interacting traits (Tortiet al. 2001). This has been well illustrated for the neotropical treeDicymbe corymbosawhose monodominance relies on: (1) ectomycorrhizal symbiosis (Henkelet al. 2002) linked to (2) mast fruiting (Henkelet al. 2005), (3) high seedling survival rate (Henkelet al. 2005, McGuire 2007a, 2007b) and, potentially, (4) slow litter decomposition (Mayor & Henkel 2006, McGuireet al. 2010), moreover, (5) the reiterative habit ofD. corymbosaslows the gap dynamics, and reduces species richness (Woolleyet al. 2008). Thus, a comprehensive understanding of monodominance may only emerge from the comparison of many case studies to point out shared mechanisms. Here, we report a new case of a monodominant species:Spirotropis longifolia(DC.) Baill.
Association of Crossword Puzzle Participation with Memory Decline in Persons Who Develop Dementia
Authors: Pillai Jagan A. , Hall Charles B. , Dickson Dennis W. , Buschke Herman , Lipton Richard B. , Verghese Joe
Published: September 2011

Participation in cognitively stimulating leisure activities such as crossword puzzles may delay onset of the memory decline in the preclinical stages of dementia, possibly via its effect on improving cognitive reserve. We followed 488 initially cognitively intact community residing individuals with clinical and cognitive assessments every 12–18 months in the Bronx Aging Study. We assessed the influence of crossword puzzle participation on the onset of accelerated memory decline as measured by the Buschke Selective Reminding Test in 101 individuals who developed incident dementia using a change point model. Crossword puzzle participation at baseline delayed onset of accelerated memory decline by 2.54 years. Inclusion of education or participation in other cognitively stimulating activities did not significantly add to the fit of the model beyond the effect of puzzles. Our findings show that late life crossword puzzle participation, independent of education, was associated with delayed onset of memory decline in persons who developed dementia. Given the wide availability and accessibility of crossword puzzles, their role in preventing cognitive decline should be validated in future clinical trials. (JINS, 2011, 17, 1006–1013)
The skinny on tuna fat: health implications
Authors: Maqbool Asim , Strandvik Birgitta , Stallings Virginia A
Published: September 2011

Objective

Dietaryn-3 (omega-3) andn-6 (omega-6) PUFA have significant implications in health and disease prevention. Marine life is rich in long-chainn-3 PUFA. Children and adults in North America are reluctant fish eaters; canned tuna is a common fish in children's diets. Although a multitude of tuna products are available, their respective PUFA contents have not been well described. The aim of the present study was to compare the fatty acid (FA) profiles of different commercially available US tuna products.

Design

Fat and FA composition of eight products randomly selected from two US suppliers were analysed with capillary GC after lipid extraction.

Setting

Large north-eastern US grocery store chain.

Subjects

Canned tuna.

Results

Energy from fat varied from 3 to 33 % and the essential FA (EFA) linoleic acid (18 : 2n-6) and α-linolenic acid (18 : 3n-3) varied tenfold. DHA varied between 90 and 770 mg/serving. Then-6:n-3 ratio was 3:1–4:1 in oil-packaged products, 2:1–7:1 in packaged tuna salads and 1:3–1:7 in water-packaged products. A similar magnitude of differences was seen in the ratio between arachidonic acid (20 : 4n-6) and DHA.

Conclusions

Light tuna canned in water may be a better choice of providingn-3 PUFA to individuals in a healthy population, whereas oil-packaged products may be preferable for those individuals with a need for increased EFA, such as for patients with cystic fibrosis. Awareness regarding PUFA content may aid in consumer product choices and health-care provider advice.
Network analysis of barley seed flows in Tigray, Ethiopia: supporting the design of strategies that contribute to on-farm management of plant genetic resources
Authors: Abay Fetien , de Boef Walter , Bjørnstad Åsmund
Published: September 2011

For maintaining food security and livelihood, farmers in marginal areas of production environments make use of high levels of crop genetic diversity. The exchange of seed and varieties among villagers, and also the relative isolation of local varieties in their production environments, contributes to the continued existence of locally adapted genotypes. In Tigray, one of the major barley-growing regions of Ethiopia, local varieties and local seed systems are dominant. The annual barley seed requirement is met with seed produced, saved and exchanged by farmers. In order to understand the flows of seed and varieties within and between villages, a study was conducted using a survey to gather information from 130 respondents in seven villages. Seed network analysis was used as an analytical tool to assess flows of seed and varieties and to identify farmers who play different roles in the seed system. Within the major seed exchange network, nodal or connector farmers linked seed subnetworks. The flow within villages was much more dominant than beyond. Rare varieties appeared to be sourced from farms that maintain a broad variety portfolio. Varieties seemed to disseminate informally across farms, in their target environments, following participatory varietal selection. The methodology of social seed network analysis proved to be a powerful tool for monitoring seed and variety flows. Furthermore, it identified farmers as critical partners in the conservation and on-farm management of plant genetic resources, recognized the role of plant breeders in participatory varietal selection and that of seed experts, engaged in strengthening local seed supply and in disseminating quality seed of superior varieties.
Characterization of the intragranular water regime within subsurface sediments: Pore volume, surface area, and mass transfer limitations
Authors: Hay Michael B. , Stoliker Deborah L. , Davis James A. , Zachara John M.
Published: September 2011

Although “intragranular” pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high‐resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium‐contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer‐free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first‐order mass transfer model. Tritium‐hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary (“wet” and “dry”) techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ∼1% of the solid volume and intragranular surface areas of ∼20%–35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity.
Effects of dynamically variable saturation and matrix‐conduit coupling of flow in karst aquifers
Authors: Reimann Thomas , Geyer Tobias , Shoemaker W. Barclay , Liedl Rudolf , Sauter Martin
Published: September 2011

Well‐developed karst aquifers consist of highly conductive conduits and a relatively low permeability fractured and/or porous rock matrix and therefore behave as a dual‐hydraulic system. Groundwater flow within highly permeable strata is rapid and transient and depends on local flow conditions, i.e., pressurized or nonpressurized flow. The characterization of karst aquifers is a necessary and challenging task because information about hydraulic and spatial conduit properties is poorly defined or unknown. To investigate karst aquifers, hydraulic stresses such as large recharge events can be simulated with hybrid (coupled discrete continuum) models. Since existing hybrid models are simplifications of the system dynamics, a new karst model (ModBraC) is presented that accounts for unsteady and nonuniform discrete flow in variably saturated conduits employing the Saint‐Venant equations. Model performance tests indicate that ModBraC is able to simulate (1) unsteady and nonuniform flow in variably filled conduits, (2) draining and refilling of conduits with stable transition between free‐surface and pressurized flow and correct storage representation, (3) water exchange between matrix and variably filled conduits, and (4) discharge routing through branched and intermeshed conduit networks. Subsequently, ModBraC is applied to an idealized catchment to investigate the significance of free‐surface flow representation. A parameter study is conducted with two different initial conditions: (1) pressurized flow and (2) free‐surface flow. If free‐surface flow prevails, the systems is characterized by (1) a time lag for signal transmission, (2) a typical spring discharge pattern representing the transition from pressurized to free‐surface flow, and (3) a reduced conduit‐matrix interaction during free‐surface flow.
Nucleolar protein Spindlin1 recognizes H3K4 methylation and stimulates the expression of rRNA genes
Authors: Wang Weixiang , Chen Zhi , Mao Zhuo , Zhang Huihui , Ding Xiaojun , Chen She , Zhang Xiaodong , Xu Ruiming , Zhu Bing
Published: September 2011

The tandem Tudor‐like domain‐containing protein Spindlin1 has been reported to be a meiotic spindle‐associated protein. Here we report that Spindlin1 is not associated with the spindle in mouse embryonic fibroblast cells during mitotic divisions. In interphase cells, Spindlin1 specifically localizes to the nucleoli. Moreover, Spindlin1 is a histone methylation effector protein that specifically recognizes H3K4 methylation. Finally, Spindlin1 localizes to the active ribosomal DNA (rDNA) repeats, and Spindlin1 facilitates the expression of rRNA genes.
PDGFR-β as a Positive Regulator of Tissue Repair in a Mouse Model of Focal Cerebral Ischemia
Authors: Shen Jie , Ishii Yoko , Xu Guihua , Dang Thanh Chung , Hamashima Takeru , Matsushima Takako , Yamamoto Seiji , Hattori Yuichi , Takatsuru Yusuke , Nabekura Junichi , Sasahara Masakiyo
Published: September 2011

Although platelet-derived growth factors (PDGFs) and receptors (PDGFRs) are abundantly expressed in the central nervous system, their functions largely remain elusive. We investigated the role of PDGFR-β in tissue responses and functional recovery after photothrombolic middle cerebral artery occlusion (MCAO). In the normal adult mouse brain, PDGFR-β was mainly localized in neurons and in pericyte/vascular smooth muscle cells (PC/vSMCs). From 3 to 28 days after MCAO, postnatally induced systemic PDGFR-β knockout mice (Esr-KO) exhibited the delayed recovery of body weight and behavior, and larger infarction volume than controls. In Esr-KO, PC/vSMC coverage was decreased and vascular leakage of infused fluorescent-labeled albumin was extensive within the ischemic lesion, but not in the uninjured cerebral cortex. Angiogenesis levels were comparable between Esr-KO and controls. In another PDGFR-β conditional KO mouse (Nestin-KO), PDGFR-β was deleted in neurons and astrocytes from embryonic day 10.5, but was preserved in PC/vSMCs. After MCAO, vascular leakage and infarction volume in Nestin-KO were worse than controls, but partly improved compared with Esr-KO. Astroglial scar formation in both Esr-KO and Nestin-KO was similarly reduced compared with controls after MCAO. These data suggested that PDGFR-β signaling is crucial for neuroprotection, endogenous tissue repair, and functional recovery after stroke by targeting neurons, PC/vSMCs, and astrocytes.
Synthesis of multi-block copolymer stars using a simple iterative Cu(0)-mediated radical polymerization technique
Authors: Boyer Cyrille , Derveaux Aurelia , Zetterlund Per B. , Whittaker Michael R.
Published: September 2011

A new iterative copper(0)-mediated radical polymerization approach is presented that represents a significant advance in the synthesis of high order multi-block star copolymers. The synthesis of these materials can now be achieved in high yield and with controlled structural complexity, with purification only required at the last step. The approach is general, facile and offers the opportunity to synthesize new copolymer stars.
The Use of Detachable Flanges on Customized Titanium Orbital Implants: A Technical Note
Authors: Mustafa Shakir F. , Bocca A. , Sugar Adrian W. , Key Steven J.
Published: September 2011

The combined use of three-dimensional reformatted images, stereolithographic models, and rapid prototyping allows the construction of an accurate, individually made titanium implant for the reconstruction of orbital floor defects. Despite the perfect fit of the custom-made plate to the model, there might be several locations on the bone where the plate may reside intraoperatively. Most titanium orbital plates therefore contain extensions over the inferior orbital rim to help locate and stabilize the plate in its position on the bone. Such over-the-rim extensions may be palpable and can cause discomfort postoperatively. We describe the use of two small detachable flanges that help to accurately locate the orbital plate in place and allow its fixation. The locating flanges are then detached and discarded, leaving a smooth implant surface within the confines of the bony orbit.
Characterization and control of crystal nucleation in amorphous electron beam evaporated silicon for thin film solar cells
Authors: Sontheimer Tobias , Scherf Simone , Klimm Carola , Becker Christiane , Rech Bernd
Published: September 2011

The kinetics of crystal nucleation in high-rate electron beam evaporated amorphous Si for polycrystalline thin film solar cells was systematically studied on SiN and selected ZnO:Al-coated glass substrates with dissimilar surface topographies by employing Raman spectroscopy, transmission electron microscopy, and optical microscopy. The influence of the surface topography of the substrate and the disorder of the deposited amorphous Si could be correlated to the respective characteristics of the transient and steady state regime of the nucleation rate. The steady state nucleation rate Iss, its corresponding activation energy EIss, and consequently the size of the grains in the crystallized Si were found to be governed by the interplay between the surface roughness and the deposition temperature. The steady state nucleation rate Iss increased gradually upon increasing the substrate roughness, while lowering the deposition temperature of the amorphous Si on rough textures resulted in a decline of Iss. The time-lag τ, which represents a distinctive parameter for the transient regime, was only slightly affected by the substrate topography. The deposition temperature, however, had a significant influence on τ, with τ increasing by a factor of 8 upon lowering the deposition temperature from 300 to 200 °C for all substrate topographies. These characteristics could be correlated with the increasing structural disorder of the deposited a-Si upon decreasing the deposition temperature. Based on this analysis, we could determine design rules for the controlled preparation of large-grained poly-Si in minimized processing time on any of the used substrate types by individually adjusting the deposition temperature and implementing nucleation layers.
Intramolecular vibrational dynamics in S1 p-fluorotoluene. I. Direct observation of doorway states
Authors: Davies Julia A. , Reid Katharine L.
Published: September 2011

Picosecond time-resolved photoelectron spectroscopy is used to investigate intramolecular vibrational redistribution (IVR) following excitation of S1 18a1 in p-fluorotoluene (pFT) at an internal energy of 845 cm−1, where ν18a is a ring bending vibrational mode. Characteristic oscillations with periods of 8 ps and 5 ps are observed in the photoelectron signal and attributed to coupling between the initially excited zero-order bright state and two doorway states. Values for the coupling coefficients connecting these three vibrational states have been determined. In addition, an exponential change in photoelectron signal with a lifetime of 17 ps is attributed to weaker couplings with a bath of dark states that play a more significant role during the latter stages of IVR. A tier model has been used to assign the most strongly coupled doorway state to S1 17a1 6a2′, where ν17a is a CH out-of-plane vibrational mode and 6a2′ is a methyl torsional level. This assignment signifies that a torsion-vibration coupling mechanism mediates the observed dynamics, thus demonstrating the important role played by the methyl torsional mode in accelerating IVR.