bluuebunny/crossref_metadata_2025 huggingface dataset:
Older Adults’ Awareness of Community Health and Support Services for Dementia Care
Authors: Ploeg Jenny , Denton Margaret , Tindale Joseph , Hutchison Brian , Brazil Kevin , Akhtar-Danesh Noori , Lillie Jean , Plenderleith Jennifer Millen
Published: November 2009

L’article examine où les personne agées peuvent chercher l’aide pour prendre soin d’un parent avec démence et les facteurs associés à leur identification des services de santé et de soutien communautaires comme des sources d’aide. Les auteurs menées des entrevues téléphoniques, à l’aide de numérotation de chiffres aléatoires, de 1,152 adultes âgés de 50 et plus dans la ville de Hamilton. À déterminer les sources de soutien, plus 37 pour cent des répondants a identifié leur médecin, 33 pour cent a identifié un soutien informel comme la famille et voisins et 31 pour cent a identifié des services de santé maison. Seulement 18 pour cent a identifié des services de soutien communautaires. Participants femmes ayant des niveaux plus élevés de scolarité étaient plus susceptibles d’identifier leur médecin comme une source de soutien. Savoir où trouver renseignements sur services de soutien communautaires était associée à une probabilité accrue de mentionnant des médecins et des services de santé maison comme sources d’aide.
Commentary on Retirement, Identity, and Erikson’s Developmental Stage Model
Authors: Osborne John W.
Published: November 2009

La coïncidence de retraite et du vieillissement, éprouvé dans les étapes ultérieures de la vie, peut déclencher une récurrence des tensions bipolaires des étapes antérieures décrites dans le modèle du développement de la personnalité d’Erikson. Le modèle fournit un moyen pour les retraités de comprendre comment le motif de leur identité actuelle a developpé et comment les psychodynamiques des étapes antérieures de la vie peut être reactivé par le début simultané de la retraite et du vieillissement. Les étapes de la modèle sont illustrés par des experiences dans la retraite. L’utilité du modèle d’Erikson est suggerée comme un moyen d’améliorer la conscience et la connaissance de soi et l’adaptation à la retraite.
Acute gastroenteritis in Hong Kong: a population-based telephone survey
Authors: HO S. C. , CHAU P. H. , FUNG P. K. , SHAM A. , NELSON E. A. , SUNG J.
Published: November 2009

A population-based telephone survey of acute gastroenteritis (AG) was conducted in Hong Kong from August 2006 to July 2007. Study subjects were recruited through random digit-dialling with recruitments evenly distributed weekly over the 1-year period. In total, 3743 completed questionnaires were obtained. An AG episode is defined as diarrhoea ⩾3 times or any vomiting in a 24-h period during the 4 weeks prior to interview, in the absence of known non-infectious causes. The prevalence of AG reporting was 7%. An overall rate of 0·91 (95% CI 0·81–1·01) episodes per person-year was observed with women having a slightly higher rate (0·94, 95% CI 0·79–1·08) than men (0·88, 95% CI 0·73–1·04). The mean duration of illness was 3·6 days (s.d.=5·52). Thirty-nine percent consulted a physician, 1·9% submitted a stool sample for testing, and 2·6% were admitted to hospital. Of the subjects aged ⩾15 years, significantly more of those with AG reported eating raw oysters (OR 2·4, 95% CI 1·3–4·4), buffet meals (OR 1·8, 95% CI 1·3–2·5), and partially cooked beef (OR 1·8, 95% CI 1·2–2·7) in the previous 4 weeks compared to the subjects who did not report AG. AG subjects were also more likely to have had hot pot, salad, partially cooked or raw egg or fish, sushi, sashimi, and ‘snacks bought at roadside’ in the previous 4 weeks. This first population-based study on the disease burden of AG in Asia showed that the prevalence of AG in Hong Kong is comparable to that experienced in the West. The study also revealed some ‘risky’ eating practices that are more prevalent in those affected with AG.
Genetic improvement in the Australasian Merino – management of a diverse gene pool for changing markets
Authors: Banks R.G. , Brown D.J.
Published: November 2009

The Australasian Merino population has declined significantly over the last 15 years in response to a decline in the price of apparel wool, both in absolute terms and relative to the price of sheep meat. Over the same period, a national genetic evaluation system based on BLUP methods has been introduced, that is achieving steady growth in adoption by breeders. Genetic parameter estimates for the population provide evidence for considerable genetic diversity for all recorded traits, providing ample opportunity for genetic improvement. More recently, there is considerable evidence for increasingly rapid progress, both in fleece traits and a range of meat production and adaptation traits. The Merino population is evolving towards two broad types – one focused on high quality apparel wools finer than 19 µm and used in enterprises with a wool/meat income ratio of about 3:1, and the other a more dual-purpose animal producing 19–21 µm wool and an enterprise wool/meat income ratio between 1.5:1 and 1:1. Underlying these trends is a growing focus on adaptation traits including worm resistance; reduced need for veterinary interventions; and increased early growth, fertility and mothering ability. Together these trends point to increasingly ‘easy-care’ sheep and exploitation of the available genetic diversity to rapidly increase profitability.
Papel de las pastoras Tzotziles en la conservación de la diversidad del ganado lanar de Chiapas
Authors: Perezgrovas-Garza Raúl
Published: November 2009

Este trabajo describe el importante papel que han tenido las pastoras de la etnia Tzotzil que habitan en las montañas de Chiapas, al sur de México, no sólo en el rescate histórico de varias razas españolas de ovejas, sino en la conservación de la biodiversidad de esta especie. Por el legado de su milenaria cultura Maya y la histórica mezcla con la religión católica, las pastoras Tzotziles son responsables de cuidar a sus ovejas sagradas, que reciben nombres propios y cuidados especiales. Las mujeres también se encargan de elaborar las ropas que identifican a su grupo étnico. Estas ropas típicas se elaboran con lana que es obtenida de las ovejas locales de la raza Chiapas, para luego ser procesada por medio de técnicas textiles artesanales como son el hilado manual y el tejido en telar de cintura de diseño prehispánico. La ropa de uso cotidiano y ceremonial de los hombres y las mujeres Tzotziles incluye abrigos de lana negra, cotones o ponchos de lana blanca, pesadas faldas negras, blusas de color café y chales negros, todos ellos hechos de lana, lo cual ha representado la necesidad de conservar la diversidad animales de distintos fenotipos dentro de los rebaños mantenidos bajo un sistema tradicional de manejo.
Microstructure and elemental composition of the Tagish Lake meteorite and its astrobiological implications
Authors: Rauf Kani , Hann Anthony , Wickramasinghe Chandra
Published: November 2009

Tagish Lake meteorite, which fell in January 2000 in Canada, has provided a sample of pristine cosmic materials for laboratory studies. It is made up of loosely formed aggregates, making it one of the most friable carbonaceous chondrites. Its complex structure is composed of plaquettes of crystalized minerals, hexagon-shaped metals, chondrules and granules, all of which are embedded in a matrix of fine grains and fibril-like materials. Those components with sizes larger than 250 nm in diameter are affected to varying degrees by hydrothermal reactions, whereas the majority of smaller bodies (<350 nm in diameter) appear unscathed despite severe aqueous alterations on the parent body. A high population of granules (100–300 nm in diameter) consist of a wall (20–40 nm in thickness) and a larger core; the former is rich in organic elements, such as carbon, oxygen and sulfur, and the core contains Ni-Fe-Mg rich silicates. The organic matter has aromatic and aliphatic characteristics, and such evidence suggests that the granules may be the carriers of large organic species with distinct astrobiological implications.
Response of early maturing maize landraces and improved varieties to moisture deficit and sufficient water supply
Authors: Menkir Abebe , Badu-Apraku Baffour , Ajala Sam , Kamara Alpha , Ndiaye Abdou
Published: November 2009

In drought-affected maize production zones with short growing periods, the development and use of early maturing drought-tolerant cultivars can stabilize maize production. We evaluated 10 improved and 25 farmers' early maturing maize varieties under moisture deficit and well-watered conditions for 2 years to identify suitable genetic materials for breeding drought-tolerant cultivars. The varieties exhibited significant differences in grain yield and other traits under both moisture deficit and well-watered conditions. Changes in the rank order of the varieties for grain yield was not significant across the different levels of moisture supply in this study. Grain yield was significantly correlated with days to anthesis, days to silking, plant height, ear height, ear number and anthesis–silking interval (ASI) under the two irrigation treatments and with leaf death scores under moisture deficit, suggesting that the common traits were beneficial in maximizing grain yield under both sufficient water supply and moisture deficit. Grain yield and the traits significantly correlated with it differentiated the early maturing maize varieties into two distinct groups under well-watered condition and moisture deficit. The improved varieties were superior to the farmers' varieties in grain yield and other traits under moisture deficit, possibly due to selection of their progenitors for improved performance in multiple locations. We found some farmers' and improved varieties with similar yield potential and flowering time under well-watered conditions but with marked differences in grain yield and other traits under moisture deficit. Use of such promising landraces that would also be invaluable sources of desirable farmers-preferred end-use quality traits in combination with promising improved varieties as breeding materials could enhance the genetic grain from selection for drought tolerance in early maize.
Three‐dimensional ray tracing of VLF waves in a magnetospheric environment containing a plasmaspheric plume
Authors: Chen Lunjin , Bortnik Jacob , Thorne Richard M. , Horne Richard B. , Jordanova Vania K.
Published: November 2009

A three dimensional ray tracing of whistler‐mode chorus is performed in a realistic magnetosphere using the HOTRAY code. A variety of important propagation characteristics are revealed associated with azimuthal density gradients and a plasmaspheric plume. Specifically, whistler mode chorus originating from a broad region on the dayside can propagate into the plasmasphere. After entry into the plasmasphere, waves can propagate eastward in MLT and merge to form hiss. This explains how chorus generated on the dayside can contribute to plasmaspheric hiss in the dusk sector. A subset of waves entering the plasmasphere can even propagate globally onto the nightside.
Yield ratio estimates using regional Pn and Pg from North Korea's underground nuclear explosions
Authors: Kim Tae Sung , Kang Ik‐Bum , Kim Geun‐Young
Published: November 2009

On May 25, 2009 North Korea executed a second nuclear test in the vicinity of P'unggyeri where the first nuclear test was performed on October 9, 2006. Seismic signals from the two underground nuclear explosions (UNEs) are recorded at broadband stations in South Korea and China. Seismic signals from fourteen broadband stations operated by the Korea Institute of Geoscience and Mineral Resources (KIGAM), three broadband stations of Korea Meteorological Administration (KMA) in South Korea and the Mudanjiang station (MDJ) of GSN in China are used for this study. Clear Pn, Pg, and Lg phases propagated over 800 km. The nearly co‐located two UNEs and seismic recordings at the same stations enable us to estimate the ratio of the Pn and Pg displacement amplitude spectra between two events by eliminating the path effect. The 95% confidence interval of the mean yield ratio is constrained as a function of the depth ratio and all the estimates of Pn and Pg spectral ratios. The mean yield ratio ranges from 3.45 to 6.36 in the 95% confidence interval based on the depth range estimates by Bennett (2008, 2009).
A North Pacific decadal variability in subduction rate
Authors: Qu Tangdong , Chen Ju
Published: November 2009

Analysis of results from a global eddy‐resolving general circulation model has revealed the existence of a North Pacific decadal variability in subduction rate. This decadal variability corresponds well with the Pacific Decadal Oscillation (PDO). The zero‐lag correlation between the two time series reaches 0.61 for the period of integration (1950–2003), and increases to as high as 0.80 after the climate shift in the mid‐1970s. Much of the North Pacific decadal variability in subduction rate is due to changes in winter mixed layer depth, which in turn are closely related to changes in surface wind and heat flux.
Computer‐generated global map of valley networks on Mars
Authors: Luo Wei , Stepinski T. F.
Published: November 2009

The presence of valley networks (VN) on Mars suggests that early Mars was warmer and wetter than present. However, detailed geomorphic analyses of individual networks have not led to a consensus regarding their origin. An additional line of evidence can be provided by the global pattern of dissection on Mars, but the currently available global map of VN, compiled from Viking images, is incomplete and outdated. We created an updated map of VN by using a computer algorithm that parses topographic data and recognizes valleys by their morphologic signature. This computer‐generated map was visually inspected and edited to produce the final updated map of VN. The new map shows an increase in total VN length by a factor of 2.3. A global map of dissection density, D, derived from the new VN map, shows that the most highly dissected region forms a belt located between the equator and mid‐southern latitudes. The most prominent regions of high values of D are the northern Terra Cimmeria and the Margaritifer Terra where D reaches the value of 0.12 km−1 over extended areas. The average value of D is 0.062 km−1, only 2.6 times lower than the terrestrial value of D as measured in the same fashion. These relatively high values of dissection density over extensive regions of the planet point toward precipitation‐fed runoff erosion as the primary mechanism of valley formation. Assuming a warm and wet early Mars, peculiarity of the global pattern of dissection is interpreted in the terms of climate controlling factors influenced by the topographic dichotomy.
Interactions between continental breakup dynamics and large‐scale delta system evolution: Insights from the Cretaceous Ceduna delta system, Bight Basin, Southern Australian margin
Authors: Espurt Nicolas , Callot Jean‐Paul , Totterdell Jennifer , Struckmeyer Heike , Vially Roland
Published: November 2009

The interpretation of two regional seismic reflection profiles and the construction of a balanced cross section through the southern Australian margin (Bight Basin) are designed to analyze the influence of the Australia‐Antarctica continental breakup process on the kinematic evolution of the Cretaceous Ceduna delta system. The data show that the structural architecture of this delta system consists of two stacked delta systems. The lower White Pointer delta system (Late Albian‐Santonian) is an unstable tectonic wedge, regionally detached seaward above Late Albian ductile shales. Sequential restoration suggests that the overall gravitational sliding behavior of the White Pointer delta wedge (∼45 km of seaward extension, i.e., ∼27%) is partially balanced by the tectonic denudation of the subcontinental mantle. We are able to estimate the horizontal stretching rate of the mantle exhumation between ∼2 and 5 km Ma−1. The associated uplift of the distal part of the margin and associated flexural subsidence in the proximal part of the basin are partially responsible for the decrease of the gravitational sliding of the White Pointer delta system. Lithospheric failure occurs at ∼84 Ma through the rapid exhumation of the mantle. The upper Hammerhead delta system (Late Santonian‐Maastrichtian) forms a stable tectonic wedge developed during initial, slow seafloor spreading and sag basin evolution of the Australian side margin. Lateral variation of basin slope (related to the geometry of the underlying White Pointer delta wedge) is associated with distal raft tectonic structures sustained by high sedimentation rates. Finally, we propose a conceptual low‐angle detachment fault model for the evolution of the Australian‐Antarctic conjugate margins, in which the Antarctic margin corresponds to the upper plate and the Australian margin to the lower plate.
Abdominal Obesity, Insulin Resistance, and the Metabolic Syndrome: Contribution of Physical Activity/Exercise
Authors: Ross Robert , Després Jean‐Pierre
Published: November 2009

The metabolic syndrome, a constellation of metabolic abnormalities, which include abdominal obesity, insulin resistance, an atherogenic dyslipidemia, elevated blood pressure, a prothrombotic profile, and inflammation is associated with an increased risk of type 2 diabetes (1), cardiovascular disease (2), and mortality (3). The prevalence of individuals with these clustering abnormalities has been steadily increasing over the past two decades, is now estimated to affect at least a quarter of the US population, and is particularly prevalent among older adults (4). Similarly, abdominal obesity, as crudely estimated by an elevated waist circumference, is the most prevalent manifestation of the metabolic syndrome and affects 36% of men and 52% of women, according to the 1999–2000 US National Health and Nutrition Examination Study (5).
Exercise Training, Lipid Regulation, and Insulin Action: A Tangled Web of Cause and Effect
Authors: Kraus William E. , Slentz Cris A.
Published: November 2009

Lipids are a strong mediator of coronary artery disease and cardiovascular risk. Although the effects of exercise to improve high‐density lipoprotein (HDL) cholesterol and serum triglycerides (TGs) have been known for some time, the effects of different amounts and intensities of exercise on fasting and postprandial serum lipids are little understood. Normal lipid physiology is perturbed in insulin resistant states, where inhibition of lipolysis is impaired, particularly in the postprandial period when excursions in insulin and serum TGs are particularly high. In our STRRIDE (Studies of a Targeted Risk Reduction Intervention through Defined Exercise) study, three important metabolic cardiovascular risk‐related variables were improved more by moderate intensity than vigorous‐intensity exercise. Moderate‐intensity exercise was significantly more effective at lowering TGs and improving insulin sensitivity than was vigorous exercise. Additionally, a composite score for metabolic syndrome improved significantly with low‐amount/moderate, but did not with low‐amount/vigorous‐intensity exercise. That all three of these strong, independent, cardiovascular risk factors were significantly affected by moderate‐intensity exercise suggests that regular walking exercise might be as effective, if not more so, than more vigorous exercise in favorably modifying cardiovascular risk. Despite the impressive effects of regular exercise on fasting lipids and atherogenic dyslipidemia, they are more impressive when compared with the trajectory of changes that occur in individuals that remain inactive, without regular exposure to regular exercise. A scientific priority for future investigations should be to study the independent and combined effects of exercise intensity and amount on exercise responses through a direct comparison between two groups matched on amount but differing in intensity.
Molecular Themes in DNA Replication
Authors: Kearsey Stephen , Campbell Judith L , Almouzni Genevieve , Poulton Joanna , Yasukawa Takehiro , Bell Steve , Laskey Ron , Kunkel Tom , Chong James , Ge Xinquan , Blow Julian , Speck Christian , Jiang Ginger , Fanning Ellen , Ulrich Helle D , Haering Christian , Chong James , Li Ji-Liang , Bryan Tracy , Walters Alison
Published: November 2009

DNA replication, the process of copying one double stranded DNA molecule to form two identical copies, is highly conserved at the mechanistic level across evolution. Interesting in its own right as a fascinating feat of biochemical regulation and coordination, DNA replication is at the heart of modern advances in molecular biology. An understanding of the process at both the biological and chemical level is essential to developing new techniques in molecular biology. Insights into the process at the molecular level provide opportunities to modulate and intervene in replication. Rapidly dividing cells need to replicate their DNA prior to division, and targeting components of the replication process is a potentially powerful strategy in cancer treatment. Conversely, ageing may be associated with loss of replication activity and restoring it to cells may moderate some of the diseases associated with old age. Replication is, therefore, fundamental to a huge range of molecular biological and biochemical applications, and provides many potential targets for drug design. The fast pace of replication research, particularly in providing new structural insights, has outdated the majority of available texts. This learned, yet accessible, book contains the latest research written by those conducting it. It examines conserved themes providing a biological background for biochemical, chemical and pharmaceutical studies of this huge and exciting field. Rather than simply "itemising" the replication steps and the proteins involved, replication is tackled from a novel perspective. The book provides logical groupings of processes based upon biochemical similarities. The emphasis on mechanisms and the relationship between structure and function targets the chapters towards biochemists and biological chemists as well as molecular and cell biologists. The book highlights new insights into the replication process, from the assembly of pre-replication complexes, through polymerisation mechanisms, to considering replication in the context of chromatin and chromosomes. It also covers mitochondrial DNA replication, and includes archaeal paradigms, which are proving increasingly relevant to the study of replication in higher eukaryotes. Exciting potential drug targets in DNA replication are discussed, particularly in the context of treating malaria and cancer.
Markov property of Gaussian states of canonical commutation relation algebras
Authors: Petz Dénes , Pitrik József
Published: November 2009

The Markov property of Gaussian states of canonical commutation relation algebras is studied. The detailed description is given by the representing block matrix. The proof is short and allows infinite dimension. The relation to classical Gaussian Markov triplets is also described. The minimizer of relative entropy with respect to a Gaussian Markov state has the Markov property. The appendix contains formulas for the relative entropy.
Size effect on magnetic and ferroelectric properties in Bi2Fe4O9 multiferroic ceramics
Authors: Tian Z. M. , Yuan S. L. , Wang X. L. , Zheng X. F. , Yin S. Y. , Wang C. H. , Liu L.
Published: November 2009

Magnetic and ferroelectric properties are investigated for the polycrystalline Bi2Fe4O9 ceramics with different grain sizes (60–2000 nm) synthesized by a modified Pechini method. It shows that magnetic and ferroelectric properties are strongly dependent on the grain size. For the 60 nm samples, the magnetization curves exhibit a superimposed behavior of antiferromagnetic (AFM) with ferromagnetic (FM) component. As the grain size increases, FM component is suppressed and AFM interaction becomes dominant. Simultaneously, the Néel temperature (TN) shifts to high temperatures as the grain size increases. Compared with the 60 nm sample, ferroelectric hysteresis loops at room temperature are observed for the samples with large grain sizes (>200 nm) due to the reduced leakage currents. Among all samples, the 900 nm sample is found to have the smallest leakage current density (<10−6) and the largest remnant polarization (0.21 μC/cm2).
Significant suppression of space charge injection into linear low density polyethylene by surface oxyfluorination
Authors: An Zhenlian , Xie Chen , Jiang Yue , Zheng Feihu , Zhang Yewen
Published: November 2009

Surface oxyfluorination of linear low density polyethylene (LLDPE) was performed to suppress space charge injection and accumulation under direct current high voltage. Significant suppression effect that there is almost no space charge inside LLDPE was obtained, as observed by space charge measurements based on the pressure wave propagation method. Oxyfluorination led to the substantial variation in chemical composition, forming the various polar groups in surface layer, as indicated by attenuated total reflection infrared analyses. The suppression mechanisms are mainly attributed to the charge trap change and the remarkable increase in permittivity of the oxyfluorinated surface layer, as investigated by open-circuit thermally stimulated discharge current measure-ments and surface energy calculations, respectively.
Reflection-mode sensing using optical microresonators
Authors: Koch Barry , Yi Yasha , Zhang Jun-Ying , Znameroski Stephen , Smith Terry
Published: November 2009

The authors present an approach for applying optical microring resonators to sensing. The approach relies on the interaction of the resonator with a nanoparticle taggant, which can induce coupling between forward and backward propagating traveling-wave resonant modes of the device. In the conventional four-port Add/Drop filter configuration, such coupling results in significant build-up of output intensity at ports that would normally be “dark.” Because the increased intensity occurs across a wide range of device resonances, the sensor may be interrogated using broadband excitation and with a broadband detector, enabling a low-cost, robust system.
Multibubble cavitation inception
Authors: Ida Masato
Published: November 2009

The inception of cavitation in multibubble cases is studied numerically and theoretically to show that it is different from that in single-bubble cases in several aspects. Using a multibubble model based on the Rayleigh–Plesset equation with an acoustic interaction term, we confirmed that the recently reported suppression of cavitation inception due to the interaction of nonidentical bubbles can take place not only in liquid mercury but also in water, and we found that a relatively large bubble can significantly decrease the cavitation threshold pressure of a nearby small bubble. By examining in detail the transition region where the dynamics of the suppressed bubble changes drastically as the interbubble distance changes, we determined that the explosive expansion of a bubble under negative pressure can be interrupted and turn into collapse even though the far-field liquid pressure well exceeds the bubble’s threshold pressure. Numerical results suggest that the interruption of expansion occurs when the bubble radius is exceeded by the instantaneous unstable equilibrium radius of the bubble determined using the total pressure acting on the bubble. When we extended the discussion to systems of larger numbers of bubbles, we found that a larger number of bubbles have a stronger suppression effect. The present findings would be useful in understanding the complex behavior of cavitation bubbles in practical applications where, in general, many cavitation nuclei exist and may interact with each other.
Exploring the Binding of Calothrixin A to the G-Quadruplex from the c-myc Oncogene Promotor
Authors: Owen Elisabeth A. , Keniry Max A.
Published: November 2009

Calothrixin A, a bioactive pentacyclic metabolite from the cyanobacteria Calothrix, has potent antiproliferative behaviour against several cancer cell lines. The in vitro binding of calothrixin A to the DNA quadruplex formed at the promotor region of c-myc was investigated by monitoring changes in the fluorescence emission of 2-aminopurine (2Ap)-substituted analogues of the native Pu22 sequence d(TGAGGGTGGGGAGGGTGGGGAA) on titration with calothrixin A and N-methoxymethyl-calothrixin B. Calothrixin A binds to Pu22 and its constituent loop isomers with a micromolar dissociation constant whereas N-methoxymethyl-calothrixin B has over an order of magnitude lower affinity. Competitive displacement experiments with double-stranded DNA showed preferential binding of calothrixin A to the Pu22 quadruplex compared with double-stranded DNA. The association of calothrixin A with DNA quadruplexes is the first direct evidence that calothrixin A binds to DNA and may aid in the understanding of the bioactivity of the calothrixins.
A Bipedal Silica-Immobilized Azo-Initiator for Surface-Confined Radical Polymerizations
Authors: Rotzoll Robert , Vana Philipp
Published: November 2009

The present study introduces the silica-anchored azo-initiator 4,4′-azobis(4-cyano-N-(3″-triethoxysilylpropyl)-valeric amide) (ACTA) for the surface-initiated polymerization of methyl acrylate (MA) with and without additional grafted reversible addition–fragmentation chain transfer (RAFT) agents 1,4-bis(3′-trimethoxysilylpropyltrithiocarbonylmethyl)benzene and 1,6-bis(o,p-2′-trimethoxysilylethylbenzyltrithiocarbonyl)hexane. While the sole use of silica-linked ACTA produced grafted poly(methyl acrylate) (pMA) of high molecular weight, due to a 2D Trommsdorff effect, the polymerization in combination with the fixed RAFT agents exhibited living behaviour with increasing molecular weights during polymerization. Silica-pMA hybrids were further analyzed via thermogravimetric analysis and scanning electron microscopy, which revealed significant differences between the three approaches.
Facile 'One-Pot' Preparation of Reversible, Disulfide-Containing Shell Cross-Linked Micelles from a RAFT-Synthesized, pH-Responsive Triblock Copolymer in Water at Room Temperature
Authors: Xu Xuewei , Smith Adam E. , McCormick Charles L.
Published: November 2009

A pH-responsive triblock copolymer, α-methoxy poly(ethylene oxide)-b-poly(N-(3-aminopropyl) methacrylamide)-β-poly(2-(diisopropylamino)ethyl methacrylate) (mPEO-PAPMA-PDPAEMA), was synthesized via aqueous RAFT polymerization. This triblock copolymer dissolves in aqueous solution at low pH (<5.0) due to protonation of primary amine residues on the PAPMA block and tertiary amine residues on the PDPAEMA block. Above pH 6.0, the copolymer unimers self-assemble into micelles consisting of PDPAEMA cores, PAPMA shells, and mPEO coronas. Dynamic light scattering studies indicated a hydrodynamic diameter of 92 nm at pH 9.0. A bifunctional, reversible cross-linker, dimethyl 3,3′-dithiobispropionimidate (DTBP), was used to cross-link the micelles. The ‘one-pot’ formation of shell cross-linked (SCL) micelles was accomplished at room temperature in water by mixing the triblock copolymers and DTBP at pH 3.0, and slowly increasing the solution pH to 9.0 leading to the simultaneous formation of micelles and cross-linking. These SCL micelles are readily cleaved by the addition of the reducing agent, dithiothreitol, and can be re-cross-linked simply by exposure to air. Such SCL micelles have potential as nanocarriers for controlled release of therapeutic and diagnostic agents because the in situ cleavage of the disulfide linkages would not only allow release of bioactive agents, but also permit renal clearance of the resulting unimeric components.
Living Radical Polymerization by the RAFT Process - A Second Update
Authors: Moad Graeme , Rizzardo Ezio , Thang San H.
Published: November 2009

This paper provides a second update to the review of reversible deactivation radical polymerization achieved with thiocarbonylthio compounds (ZC(=S)SR) by a mechanism of reversible addition–fragmentation chain transfer (RAFT) that was published in June 2005 (Aust. J. Chem. 2005, 58, 379–410). The first update was published in November 2006 (Aust. J. Chem. 2006, 59, 669–692). This review cites over 500 papers that appeared during the period mid-2006 to mid-2009 covering various aspects of RAFT polymerization ranging from reagent synthesis and properties, kinetics and mechanism of polymerization, novel polymer syntheses and a diverse range of applications. Significant developments have occurred, particularly in the areas of novel RAFT agents, techniques for end-group removal and transformation, the production of micro/nanoparticles and modified surfaces, and biopolymer conjugates both for therapeutic and diagnostic applications.
Lethal factor unfolding is the most force-dependent step of anthrax toxin translocation
Authors: Thoren Katie L. , Worden Evan J. , Yassif Jaime M. , Krantz Bryan A.
Published: November 2009

Cellular compartmentalization requires machinery capable of translocating polypeptides across membranes. In many cases, transported proteins must first be unfolded by means of the proton motive force and/or ATP hydrolysis. Anthrax toxin, which is composed of a channel-forming protein and two substrate proteins, is an attractive model system to study translocation-coupled unfolding, because the applied driving force can be externally controlled and translocation can be monitored directly by using electrophysiology. By controlling the driving force and introducing destabilizing point mutations in the substrate, we identified the barriers in the transport pathway, determined which barrier corresponds to protein unfolding, and mapped how the substrate protein unfolds during translocation. In contrast to previous studies, we find that the protein's structure next to the signal tag is not rate-limiting to unfolding. Instead, a more extensive part of the structure, the amino-terminal β-sheet subdomain, must disassemble to cross the unfolding barrier. We also find that unfolding is catalyzed by the channel's phenylalanine-clamp active site. We propose a broad molecular mechanism for translocation-coupled unfolding, which is applicable to both soluble and membrane-embedded unfolding machines.
Subcellular localization of marine bacterial alkaline phosphatases
Authors: Luo Haiwei , Benner Ronald , Long Richard A. , Hu Jianjun
Published: November 2009

Bacterial alkaline phosphatases (APases) are important enzymes in organophosphate utilization in the ocean. The subcellular localization of APases has significant ecological implications for marine biota but is largely unknown. The extensive metagenomic sequence databases from the Global Ocean Sampling Expedition provide an opportunity to address this question. A bioinformatics pipeline was developed to identify marine bacterial APases from the metagenomic databases, and a consensus classification algorithm was designed to predict their subcellular localizations. We identified 3,733 bacterial APase sequences (including PhoA, PhoD, and PhoX) and found that cytoplasmic (41%) and extracellular (30%) APases exceed their periplasmic (17%), outer membrane (12%), and inner membrane (0.9%) counterparts. The unexpectedly high abundance of cytoplasmic APases suggests that the transport and intracellular hydrolysis of small organophosphate molecules is an important mechanism for bacterial acquisition of phosphorus (P) in the surface ocean. On average, each marine bacterium possessed at least one suite of uptake of glycerol phosphate (ugp) genes (e.g., ugpA, ugpB, ugpC, ugpE) for dissolved organic phosphorus (DOP) transport, but only half of them had ugpQ, which hydrolyzes transported DOP, indicating that cytoplasmic APases play a role in hydrolyzing transported DOP. The most abundant heterotrophic marine bacteria, α- and γ-Proteobacteria, might hydrolyze DOP outside the cytoplasmic membrane, but the former could also transport and hydrolyze DOP in the cytoplasm. The abundant extracellular APases could provide bioavailable P for organisms that cannot directly access organophosphates, and thereby increase marine biological productivity and diversity.
Trypsin is a multifunctional factor in spermatogenesis
Authors: Miura Chiemi , Ohta Takashi , Ozaki Yuichi , Tanaka Hideki , Miura Takeshi
Published: November 2009

Trypsin is well known as a pancreatic enzyme that is typically secreted into the intestine to digest proteins. We show in our current study, however, that trypsin is also a key factor in the control of spermatogenesis. A progestin in teleost fish, 17α, 20β-dihydroxy-4-pregnen-3-one (DHP), is an essential component of the spermatogenesis pathway, particularly during the initiation of the first meiotic division. In the course of our investigations into the mechanisms underlying progestin-stimulated spermatogenesis, we identified that eel trypsinogen is upregulated in eel testis by DHP treatment. Trypsinogen is expressed in the Sertoli cells surrounding spermatogonia and in the membranes of spermatids and spermatozoa. Using an in vitro eel testicular culture system, we further analyzed the roles of trypsin in spermatogenesis. The inhibition of trypsin using specific antibodies or serine protease inhibitors was found to compromise DHP-induced spermatogenesis. A low dose of trypsin induces DNA synthesis and the expression of Spo11, a molecular marker of meiosis, in germ cells. By comparison, a higher dose of trypsin partially induced spermiogenesis. Furthermore, trypsin was detectable in the membranes of the spermatozoa and found to be associated with fertilization in fish. Our results thus demonstrate that trypsin and/or a trypsin-like protease is an essential and multifunctional factor in spermatogenesis.
Phase-dependent neuronal coding of objects in short-term memory
Authors: Siegel Markus , Warden Melissa R. , Miller Earl K.
Published: November 2009

The ability to hold multiple objects in memory is fundamental to intelligent behavior, but its neural basis remains poorly understood. It has been suggested that multiple items may be held in memory by oscillatory activity across neuronal populations, but yet there is little direct evidence. Here, we show that neuronal information about two objects held in short-term memory is enhanced at specific phases of underlying oscillatory population activity. We recorded neuronal activity from the prefrontal cortices of monkeys remembering two visual objects over a brief interval. We found that during this memory interval prefrontal population activity was rhythmically synchronized at frequencies around 32 and 3 Hz and that spikes carried the most information about the memorized objects at specific phases. Further, according to their order of presentation, optimal encoding of the first presented object was significantly earlier in the 32 Hz cycle than that for the second object. Our results suggest that oscillatory neuronal synchronization mediates a phase-dependent coding of memorized objects in the prefrontal cortex. Encoding at distinct phases may play a role for disambiguating information about multiple objects in short-term memory.
Gaining ligand selectivity in thyroid hormone receptors via entropy
Authors: Martínez Leandro , Nascimento Alessandro S. , Nunes Fabio M. , Phillips Kevin , Aparicio Ricardo , Dias Sandra Martha G. , Figueira Ana Carolina M. , Lin Jean H. , Nguyen Phuong , Apriletti James W. , Neves Francisco A. R. , Baxter John D. , Webb Paul , Skaf Munir S. , Polikarpov Igor
Published: November 2009

Nuclear receptors are important targets for pharmaceuticals, but similarities between family members cause difficulties in obtaining highly selective compounds. Synthetic ligands that are selective for thyroid hormone (TH) receptor β (TRβ) vs. TRα reduce cholesterol and fat without effects on heart rate; thus, it is important to understand TRβ-selective binding. Binding of 3 selective ligands (GC-1, KB141, and GC-24) is characterized at the atomic level; preferential binding depends on a nonconserved residue (Asn-331β) in the TRβ ligand-binding cavity (LBC), and GC-24 gains extra selectivity from insertion of a bulky side group into an extension of the LBC that only opens up with this ligand. Here we report that the natural TH 3,5,3′-triodothyroacetic acid (Triac) exhibits a previously unrecognized mechanism of TRβ selectivity. TR x-ray structures reveal better fit of ligand with the TRα LBC. The TRβ LBC, however, expands relative to TRα in the presence of Triac (549 Å
3
vs. 461 Å
3
), and molecular dynamics simulations reveal that water occupies the extra space. Increased solvation compensates for weaker interactions of ligand with TRβ and permits greater flexibility of the Triac carboxylate group in TRβ than in TRα. We propose that this effect results in lower entropic restraint and decreases free energy of interactions between Triac and TRβ, explaining subtype-selective binding. Similar effects could potentially be exploited in nuclear receptor drug design.
Minute synthesis of extremely stable gold nanoparticles
Authors: Zhou Min , Wang Baoxiang , Rozynek Zbigniew , Xie Zhaohui , Fossum Jon Otto , Yu Xiaofeng , Raaen Steinar
Published: November 2009

We describe a rapid environmentally friendly wet-chemical approach to synthesize extremely
stable non-toxic, biocompatible, water-soluble monodispersed gold nanoparticles (AuNPs) in
one step at room temperature. The particles have been successfully achieved in just a few
minutes by merely adding sodium hydroxide (NaOH) acting as an initiator for the reduction of
HAuCl4
in aqueous solution in the presence of polyvinylpyrrolidone (PVP) without the use of any
reducing agent. It is also proved to be highly efficient for the preparation of AuNPs with
controllable sizes. The AuNPs show remarkable stability in water media with high
concentrations of salt, various buffer solutions and physiological conditions in biotechnology
and biomedicine. Moreover, the AuNPs are also non-toxic at high concentration (100 µM). Therefore, it provides great opportunities to use these AuNPs for biotechnology and
biomedicine. This new approach also involved several green chemistry concepts, such as the
selection of environmentally benign reagents and solvents, without energy consumption,
and less reaction time.
Increased plasma retinol binding protein 4 levels in patients with inflammatory cardiomyopathy
Authors: Bobbert Peter , Weithäuser Alice , Andres Janin , Bobbert Thomas , Kühl Uwe , Schultheiss Heinz Peter , Rauch Ursula , Skurk Carsten
Published: November 2009

Aims

Chronic heart failure (CHF) is associated with a higher risk for diabetes mellitus. Retinol binding protein 4 (RBP 4) is an adipose tissue‐derived protein with pro‐diabetogenic effects. A complete understanding of the association of CHF and insulin resistance remains elusive. The purpose of this study was to examine the relationship between CHF and diabetes mellitus.

Methods and results

Plasma levels of RBP 4, insulin, and interleukins (IL) 2, 8, and 10, were assessed in patients with dilated cardiomyopathy (DCM, n = 53), dilated inflammatory cardiomyopathy (DCMi, n = 54), and controls (n = 20). In addition, a possible mechanism of RBP 4 regulation was examined in adipocytes in vitro. Plasma levels of RBP 4 and insulin were measured by a specific ELISA. Interleukin concentrations were obtained by multiplex ELISA. Cell culture with 3T3‐L1 adipocytes was performed to measure RBP 4 mRNA expression after stimulation with IL‐8. RBP 4 levels were significantly increased in patients with DCMi (52.95 ± 20.42 µg/mL) compared with DCM (35.54 ± 23.08 µg/mL) and the control group (27.3 ± 18.51 µg/mL). RBP 4 was positively correlated with IL‐8 (r=0.416, P < 0.05) in human plasma in patients with DCMi. Moreover, increased insulin resistance was observed in patients with DCMi compared with the control and DCM groups. In vitro, IL‐8 induced a significant upregulation of RBP 4 mRNA expression in adipocytes.

Conclusion

Elevated RBP 4 plasma concentrations, induced by IL‐8, might be one mechanism leading to a higher incidence of diabetes in patients with DCMi.
Right atrial size and deformation in patients with dilated cardiomyopathy undergoing cardiac resynchronization therapy
Authors: D'Andrea Antonello , Scarafile Raffaella , Riegler Lucia , Salerno Gemma , Gravino Rita , Cocchia Rosangela , Castaldo Francesca , Allocca Filomena , Limongelli Giuseppe , Di Salvo Giovanni , Cuomo Sergio , Pacileo Giuseppe , Caso Pio , Russo Maria Giovanna , Calabrò Raffaele
Published: November 2009

Aims

To evaluate right atrial (RA) morphology and deformation in patients with dilated cardiomyopathy (DCM).

Methods and results

A total of 130 patients with either idiopathic (n = 70) or ischaemic (n = 60) DCM, and 60 controls underwent clinical examination, standard echocardiography, and RA two‐dimensional strain echocardiography (2DSE). Six months after implantation of a cardiac resynchronization therapy (CRT) device, the DCM patients were re‐evaluated, if their left ventricular (LV) end‐systolic volume had decreased by at least 15% they were defined as echocardiographic responders. All DCM patients were in NYHA class III before CRT, with a mean LV ejection fraction of 29.2 ± 5.5%. After CRT, 94 patients were in NYHA functional class I–II. The patients were subdivided into echocardiographic responders (n = 85) and non‐responders (n = 45). Both RA area index (19.7 ± 5.5 cm2/m in non‐responders vs. 13.2 ± 4.4 cm2/m in responders; P < 0.001) and RA strain of lateral wall (24.3 ± 10.2% in non‐responders vs. 40.2 ± 8.9% in responders; P < 0.001) were significantly different between the two groups. A RA area index ≥16 cm2/m showed a sensitivity and specificity of 87.1 and 95.4%, respectively (P < 0.0001) to predict a negative response to CRT. By multivariable analysis, increased RA area index (P < 0.001), ischaemic aetiology of DCM (P < 0.01), and less severe radial intraventricular dyssynchrony were independent determinants of an unfavourable response to CRT.

Conclusion

Right atrial area index was increased and RA myocardial deformation was impaired in patients with DCM who were non‐responders to CRT.
Novel Influenza A (H1N1) Outbreak On Board a US Navy Vessel
Authors: Dill Curt E. , Favata Michael A.
Published: November 2009

Background and Methods: Fleet Week New York 2009 was the latest installment of an annual celebration to honor US service personnel. It takes place during Memorial Day and this year’s celebration coincided with the peak of novel influenza A (H1N1) virus (S-OIV) activity in New York City. Four service members from the USS Iwo Jima and USS Roosevelt contracted influenza while in New York City and were hospitalized in the Department of Veterans Affairs (VA)-New York Harbor Healthcare System to minimize the risk of widespread outbreak on board the naval vessels. No additional cases were identified on the USS Roosevelt. However, 135 service personnel on the USS Iwo Jima contracted influenza.

Results: Shipwide infection control measures including strict isolation and active case finding were instituted immediately with affected crew members and medical staff receiving oseltamivir. The new case rates remained high for 14 days, but the USS Iwo Jima was able to continue deployment. The secondary infectivity rate was 12.0%. The absolute end of the outbreak correlated with arrival at home port and the ability to move patients off board.

Conclusions: This outbreak not only reinforces the risk for rapid spread of novel strains of influenza A in confined populations but also demonstrates useful strategies to mitigate the severity of an outbreak, including isolation, infection control measures, and off board sick leave when feasible. (Disaster Med Public Health Preparedness. 2009;3(Suppl 2):S117–S120)