bluuebunny/crossref_metadata_2025 huggingface dataset:
Geographical patterns of phenotypic diversity and structure of Kenyan wild sorghum populations (Sorghum spp.) as an aid to germplasm collection and conservation strategy
Authors: Muraya Moses M. , Geiger Hartwig H. , Mutegi Evans , Kanyenji Ben M. , Sagnard Fabrice , de Villiers Santie M. , Kiambi Dan , Parzies Heiko K.
Published: July 2010

Kenya lies within sorghum centre of diversity. However, information on the relative extent of diversity patterns within and among genetically defined groups of distinct ecosystems is lacking. The objective was to assess the structure and phenotypic diversity of wild sorghum populations across a range of geographical and ecological conditions in the country. Sixty-two wild sorghum populations (30 individuals per population) sampled from four distinct sorghum growing regions of Kenya and covering different agroecologies were characterized for ten qualitative traits. Plant height, number of tillers, panicle sizes and flag leaf dimensions were also recorded. Frequencies of the phenotypic classes of each character were calculated. The Shannon diversity index (H′) was used to estimate the magnitude of diversity. Principal component analysis was used to differentiate populations within and between regions. Wild sorghum is widely distributed in Kenya, occurring in sympatric ranges with cultivated sorghum, and both have overlapping flowering windows. All characters considered displayed great phenotypic diversity. Pooled over characters within regions, the mean H′ ranged between 0.60 and 0.93 in Western and Coast regions, respectively. Wild sorghum was found to show a weak regional differentiation, probably reflecting the importance of seed-mediated gene flow in shaping the wild sorghum population structure. Trait distribution was variable among regions, but there was no conspicuous distribution of the traits studied in any given region. Spontaneous hybridization and introgression of genes from cultivated to wild sorghum seems to be likely, and may already have occurred for a long time, although undocumented. Implications for in situ and ex situ genetic resources conservation are discussed.
Seismic expression of magma‐induced crustal strains and localized fluid pressures during initial eruptive stages, Soufrière Hills Volcano, Montserrat
Authors: Miller V. , Voight B. , Ammon C. J. , Shalev E. , Thompson G.
Published: July 2010

We explore volcanotectonic earthquake activity during the early stages of volcanic activity (1995–96) at Soufrière Hills volcano. We focus on several zones of temporally‐confined seismic activity that comprise assemblages of small scale structural elements, >2–4 km distant from the volcano, at depths 2–4 km below sea level, and consider seismicity in relation to regional tectonics and heterogeneity of stiffness and strength as revealed by the SEA‐CALIPSO tomography experiment. The clustered seismicity and relatively aseismic zones are interpreted to reflect a broad weakened tectonic zone of ESE trend that crosses Montserrat, and the ascent of a magmatic dike of NNE trend, which altered the stress distribution to promote localized fault movements and caused localized dilatation with changes in pore‐fluid pressures, to either weaken or strengthen the rock mass depending on the local polarity of strain.
Population dynamics of Vibrio spp. associated with marine sponge microcosms
Authors: Hoffmann Maria , Fischer Markus , Ottesen Andrea , McCarthy Peter J , Lopez Jose V , Brown Eric W , Monday Steven R
Published: July 2010

Vibrio is a diverse genus of marine-associated bacteria with at least 74 species and more expected as additional marine ecospheres are interrogated. This report describes a phylogenetic reconstruction of Vibrio isolates derived from one such unique ecosystem, marine sponges (Phylum Porifera) collected from depths of 150 to 1242 feet. 16S rRNA gene sequencing along with molecular typing of 16S–23S rRNA intergenic spacer regions clustered many sponge-associated Vibrio (spp) with current known species. That is, several benthic Vibrio species commensal with Porifera sponges seemed genetically linked to vibrios associated with coastal or shallow-water communities, signalling a panmictic population structure among seemingly ecologically disparate strains. Conversely, phylogenetic analysis provided evidence for at least two novel Vibrio speciation events within this specific sponge microcosm. Collectively, these findings earmark this still relatively unknown environment as a bastion of taxonomic and phylogenetic variability for the genus and probably other bacterial taxa.
Effect of nitrogen fertilization on methane oxidation, abundance, community structure, and gene expression of methanotrophs in the rice rhizosphere
Authors: Shrestha Minita , Shrestha Pravin Malla , Frenzel Peter , Conrad Ralf
Published: July 2010

Nitrogen, one of the limiting factors for the yield of rice, can also have an important function in methane oxidation, thus affecting its global budget. Rice microcosms, planted in the greenhouse, were treated with the N-fertilizers urea (UPK) and ammonium sulfate (APK) or were only treated with phosphorous and potassium (PK). Methane oxidation rates in PK and UPK treatments were similar during most of the rice-growing season, revealing no effect of urea. However, ammonium sulfate strongly suppressed methanogenesis providing an unfavorable environment for methanotrophs in APK treatment. Roots and rhizospheric soil samples, collected from six different growth stages of the rice plant, were analyzed by terminal restriction fragment length polymorphism (T-RFLP) of the pmoA gene. Assignment of abundant T-RFs to cloned pmoA sequences indicated that the populations on roots were dominated by type-I methanotrophs, whereas the populations in rhizospheric soil were dominated by type-II methanotrophs irrespectively of growth stages and fertilizer treatments. Non-metric multidimensional scaling ordination analysis of T-RFLP profiles revealed that the methanotrophic community was significantly (P<0.001) affected by the different fertilizer treatments; however, the effect was stronger on the roots than in the rhizospheric soil. Contrary to pmoA gene-based analysis, pmoA transcript-based T-RFLP/cloning/sequencing analysis in rhizospheric soil showed type I as the predominant methanotrophs in both PK and UPK treatments. Collectively, our study showed that type-I methanotrophs were dominant and probably active in rhizospheric soil throughout the season irrespective of nitrogen fertilizer used, whereas type-II methanotrophs were relatively more dominant under unfavorable conditions, such as in APK treatment.
Index of Productive Syntax for Children Who Speak African American English
Authors: Oetting Janna B. , Newkirk Brandi L. , Hartfield Lekeitha R. , Wynn Christy G. , Pruitt Sonja L. , Garrity April W.
Published: July 2010

Purpose

The validity of the Index of Productive Syntax (IPSyn; Scarborough, 1990) for children who speak African American English (AAE) was evaluated by conducting an item analysis and a comparison of the children’s scores as a function of their maternal education level, nonmainstream dialect density, age, and clinical status.

Method

The data were language samples from 62 children; 52 of the children were between the ages of 4 and 6 years and were classified as developing typically, and 10 were 6 years old with specific language impairment (SLI).

Results

All IPSyn items were produced by at least 1 child, and 88% of the items were produced by 50% or more of the children. The children’s IPSyn scores were unrelated to maternal education level and dialect density and were visually comparable to IPSyn scores reported for children who speak mainstream English. Nevertheless, IPSyn could not be used to detect differences between the 4- to 6-year-olds based on age, nor could it be used to detect differences between the 6-year-olds with and without SLI.

Conclusion

IPSyn is a valid measure for AAE speakers, but it can be insensitive to age and clinical differences between children who are over the age of 48 months.
Impact of Chromosome 4p- Syndrome on Communication and Expressive Language Skills: A Preliminary Investigation
Authors: Marshall Althea T.
Published: July 2010

Purpose

The purpose of this investigation was to examine the impact of Chromosome 4p- syndrome on the communication and expressive language phenotype of a large cross-cultural population of children, adolescents, and adults.

Method

A large-scale survey study was conducted and a descriptive research design was used to analyze quantitative and qualitative data regarding the communication and expressive language manifestations of 200 children, youth, and adults from 16 countries and Puerto Rico who had been diagnosed with 4p conditions, including Wolf-Hirschhorn syndrome (WHS), Pitt-Rogers-Danks syndrome (PRDS), Proximal 4p Deletion syndrome, and complex chromosomal rearrangements associated with 4p-.

Results

Individuals with Chromosome 4p- syndrome represent a heterogeneous population with complex phenotypic profiles. The majority of the participants exhibited communication and expressive language skills below the 36-month developmental functioning level. A relatively small cohort of the study population exhibited advanced expressive language skills, a finding not reported in the professional literature.

Conclusion

Results broaden the spectrum of expressive language skills associated with Chromosome 4p- syndrome and highlight the communication potential of a subset of individuals with 4p abnormalities for development of advanced language structures. It is hypothesized that the largest 4p deletion, which includes the 4p16.3 band and contiguous gene regions, results in the most severely affected expressive language phenotype.
Spatially localized binary fluid convection in a porous medium
Authors: Lo Jacono D. , Bergeon A. , Knobloch E.
Published: July 2010

The origin and properties of time-independent spatially localized binary fluid convection in a layer of porous material heated from below are studied. Different types of single and multipulse states are computed using numerical continuation, and the results related to the presence of homoclinic snaking of single and multipulse states.
Low-loss spinel nanoferrite with matching permeability and permittivity in the ultrahigh frequency range
Authors: Thakur A. , Chevalier A. , Mattei J.-L. , Queffélec P.
Published: July 2010

Ferrite nanoparticles with a composition of Ni0.5Zn0.3Co0.2Fe2O4 were prepared by a coprecipitation method. The sample obtained after treating at appropriating conditions had almost equal real permeability and permittivity, of 4.8+j0.15 (loss tangent∼0.04) and 4.9+j0.10 (loss tangent∼0.018), respectively, over 100 to 500 MHz. This material had a refractive index n of close to 5 and a reduced impedance Z/Z0 of close to 1. These properties make the material useful to the design of miniaturized antennas at very high frequency-ultra high frequency (VHF-UHF) (100–500 MHz) bands.
Polarization screening and induced carrier density at the interface of LaAlO3 overlayer on SrTiO3 (001)
Authors: Li Yun , Yu Jaejun
Published: July 2010

We investigate the role of lattice polarization in determination of induced carrier density at the n-type interface of LaAlO3 overlayer on SrTiO3 (001) by carrying out density-functional-theory calculations. When no oxygen vacancy or defect is present, the magnitude of polarization screening in the LaAlO3 layers is found to be correlated with the carrier charge induced at the interface. For the interfaces with less than seven LaAlO3 layers, the density of induced carrier is smaller than 0.1 electrons per unit-cell and the electrostatic screening can be covered by the interface state consisting of Ti dxy state. When the overlayer becomes thicker, the extended bound state in the SrTiO3 side contributes to the charge screening.
Sodium migration pathways in multicomponent silicate glasses: Car–Parrinello molecular dynamics simulations
Authors: Tilocca Antonio
Published: July 2010

The mechanism of sodium migration in low-silica alkali-alkaline earth silicate glasses is investigated through Car–Parrinello molecular dynamics (MD) simulations. The transport of sodium to the glass surface and its subsequent release is critical for the use of these glasses in biomedical applications. The analysis of the MD trajectory, mainly through a combination of space and time correlation functions, reveals a complex mechanism, with some common features to the migration in mixed-alkali silicate glasses and several important differences. The low site selectivity of Na cations in this glass allows them to use both Na and Ca sites in the migration process. The high fragmentation and the corresponding flexibility of the silicate network enable an additional mechanism for ion migration, not favorable in the more rigid network of common higher-silica glasses, involving the creation of empty transient sites through the correlated forward-backward motion of an Na or a Ca cation. We also show that because sodium migration must involve an undercoordinated intermediate, sharing of oxygen atoms in the initial and final coordination shells is a way to reduce the energetic cost of losing favorable Na–O interactions and Na migration proceeds between corner-sharing NaOx polyhedra, where x=5–7. For these low-silica compositions, the present simulations suggest that due to the participation of calcium in the Na migration, the latter will not be significantly hampered by extensive mixing with less mobile Ca ions, or, in any event, the effect will be less marked than for higher-silica glasses.
Asymmetric magnetic NOT gate and shift registers for high density data storage
Authors: Zeng Huang T. , Read D. , O’Brien L. , Sampaio J. , Lewis E. R. , Petit D. , Cowburn R. P.
Published: July 2010

We have developed an asymmetric ferromagnetic NOT gate and shift register optimized on a square grid. This gives rise to a two-dimensional storage scheme built up by tessellating an elementary data unit, which is scalable down to very narrow wire widths. The areal footprint of each storage unit is 15F2, where F is the minimum feature size. We experimentally demonstrate NOT operations across a chain of three gates made from Permalloy with F=60 nm, and present a functional 15-gate, multichannel shift register with electrical injection, and optical readout.
A bivariate generalization of Hermite’s interpolation formula
Authors: Ahlin A. C.
Published: July 2010

One of the most commonly used methods for deriving formulas for bivariate interpolation is that of extending to two variables the formulas of Lagrange, Aitken, Newton, Gauss, Stirling, Everett, Bessel, etc., in which forward, backward and central-differences are used. These formulas have the property that the resulting interpolation polynomial agrees with the interpolated function,

f
(
x
,

y
)

f(x,\,y)

, at each of the node points of a Cartesian grid. In this study, we shall investigate the existence of a wider class of interpolation formulas, together with their associated error terms, than those obtainable by the method just described. To this end, we develop a bivariate osculatory interpolation polynomial which not only agrees with

f
(
x
,

y
)

f(x,\,y)

in function values at each of the node points of a Cartesian grid but which also enjoys the property that agreement in values of partial and mixed partial derivatives up to specified, arbitrary orders is obtainable at these points. The result is essentially a bivariate generalization of Hermite’s interpolation formula.
A conjecture of Paul Erdo’s concerning Gaussian primes
Authors: Jordan J. H. , Rabung J. R.
Published: July 2010

Paul Erdös has conjectured that you can stroll from the origin of the complex plane to infinity using the Gaussian primes as stepping stones and be required only to take steps of finite length. This paper establishes that steps of length 4 would be required to make the journey.
Inequalities on the elements of the inverse of a certain tridiagonal matrix
Authors: Kershaw D.
Published: July 2010

Inequalities are obtained for the elements in the inverse of a tridiagonal matrix with positive off-diagonal elements.
Generalized rational Chebyshev approximation
Authors: Ninomiya Ichizo
Published: July 2010

In this paper, a generalized rational Chebyshev approximation problem is considered. The problem is this: To minimize the maximum absolute value of the "criterion function" of the error. By imposing a rather natural restriction on the criterion function, the problem is solved completely; the existence, the uniqueness and the characterization of the best approximation are clarified and interesting relationships between the best approximations corresponding to different criterion functions are found. The theory is applied to the starting rational approximation for Newton iteration for

x

1

/

n

{x^{1/n}}

.
Elliptic spline functions and the Rayleigh-Ritz-Galerkin method
Authors: Schultz Martin H.
Published: July 2010

Error estimates for the Rayleigh-Ritz-Galerkin method, using finite-dimensional spline type spaces, for a class of nonlinear two-point boundary value problems are discussed. The results of this paper extend and improve recent corresponding results of B. L. Hulme, F. M. Perrin, H. S. Price, and R. S. Varga.
Deficiencies in circulating testosterone and dehydroepiandrosterone sulphate, and depression in men with systolic chronic heart failure
Authors: Jankowska Ewa A. , Drohomirecka Anna , Ponikowska Beata , Witkowska Agnieszka , Lopuszanska Monika , Szklarska Alicja , Borodulin‐Nadzieja Ludmila , Banasiak Waldemar , Poole‐Wilson Philip A. , Ponikowski Piotr
Published: July 2010

Aims

Elderly men with androgen deficiencies are prone to develop late‐onset depression. We investigated links between circulating androgens and depression, and their combined impact on outcome in men with chronic heart failure (CHF).

Methods and results

Serum total testosterone (TT) and dehydroepiandrosterone sulphate (DHEAS) were measured using immunoassays in 163 men with stable systolic CHF [age: 60 ± 10 years, NYHA class (I/II/III/IV): 27/84/46/6] and 316 healthy men. Depression was assessed using Beck Depression Inventory (BDI) and defined as BDI ≥16 points. In men with CHF, reduced TT and DHEAS, advanced NYHA class, elevated N‐terminal pro‐B type natriuretic peptide (NT‐proBNP), reduced glomerular filtration rate, and reduced haemoglobin independently predicted severity of depressive symptoms (all P < 0.05). Depression was present in 20, 37 and 77% of men with no androgen deficiency, either TT or DHEAS deficiency, and both androgen deficiencies, respectively (P < 0.0001). During follow‐up (median: 28 months), there were 87 (53%) cardiovascular deaths or unplanned hospitalizations. TT and DHEAS deficiencies (defined as ≤ the 10th percentile of serum androgen levels in healthy controls) and BDI ≥16 points independently predicted unfavourable outcome (all P < 0.05).

Conclusion

TT and DHEAS deficiencies predict severity of depression in men with CHF. Depression and combined androgen deficiencies are independently related to poor outcome in these patients.
Development and Feasibility of a Scale to Assess Postoperative Recovery
Authors: Royse Colin F. , Newman Stanton , Chung Frances , Stygall Jan , McKay Rachel E. , Boldt Joachim , Servin Frederique S. , Hurtado Ignacio , Hannallah Raafat , Yu Buwei , Wilkinson David J.
Published: July 2010

Background

Good postoperative recovery is increasingly recognized as an important outcome after surgery. The authors created a new Post-operative Quality Recovery Scale (PQRS) that tracks multiple domains of recovery from immediate to long-term time periods in patients of varying ages, languages, and cultures.

Methods

The parameters of importance to both clinicians and patients were identified. After an initial pilot study of 133 patients, the PQRS was refined. It consists of six domains (physiologic, nociceptive, emotive, activities of daily living, cognitive, and overall patient perspective). An observational study of 701 patients was performed with the refined PQRS to assess its capacity to evaluate and track recovery and to discriminate between patients. It was conducted in eight countries and in five languages, involving patients more than or equal to 6 yr undergoing elective surgery with general anesthesia. Recovery was assessed before surgery and at multiple time periods postoperatively. Recovery was defined as return to baseline values or better.

Results

Seven hundred one patients completed the PQRS. Mean completion time was 4.8 (SD 2.8) min. Recovery scores improved with time. Physiologic recovery was complete in 34% of subjects by 40 min. By the third postoperative day, complete recovery was obtained in 11% of cases (all domains): 48.7% nociceptive, 81.8% emotive, 68.8% activities of daily living, and only 33.5% cognitive. Overall, 95.8% of the patients reported that they were "satisfied or totally satisfied" with their anesthetic care.

Conclusion

The scores on the PQRS demonstrated an improvement over time, consistent with an expected recovery after surgery and anesthesia, and an ability to discriminate between individuals. Many patients had incomplete recovery by the third postoperative day.
The Streptomyces coelicolor genome encodes a type I ribosome-inactivating protein
Authors: Reyes Ana G. , Geukens Nick , Gutschoven Philip , De Graeve Stijn , De Mot René , Mejía Armando , Anné Jozef
Published: July 2010

Ribosome-inactivating proteins (RIPs) are cytotoxicN-glycosidases identified in numerous plants, but also constitute a subunit of the bacterial Shiga toxin. Classification of plant RIPs is based on the absence (type I) or presence (type II) of an additional lectin module. In Shiga toxin, sugar binding is mediated by a distinct RIP-associated homopentamer. In the genome of two actinomycetes, we identified RIP-like proteins that resemble plant type I RIPs rather than the RIP subunit (StxA) of Shiga toxin. Some representatives ofβ- andγ-proteobacteria also contain genes encoding RIP-like proteins, but these are homologous to StxA. Here, we describe the isolation and initial characterization of the RIP-like gene product SCO7092 (RIPsc) from the Gram-positive soil bacteriumStreptomyces coelicolor. Theripscgene was expressed inEscherichia colias a recombinant protein of about 30 kDa, and displayed the characteristicN-glycosidase activity causing specific rRNA depurination. InStreptomyces lividansandE. coli, RIPsc overproduction resulted in a dramatic decrease in the growth rate. In addition, intracellular production was deleterious forSaccharomyces cerevisiae. However, when applied externally to microbial cells, purified RIPsc did not display antibacterial or antifungal activity, suggesting that it cannot enter these cells. In a cell-free system, however, purifiedS. coelicolorRIPsc protein displayed strong inhibitory activity towards protein translation.
Regional cerebral oxygenation by NIRS does not correlate with central or jugular venous oxygen saturation during interventional catheterisation in children
Authors: KNIRSCH W. , STUTZ K. , KRETSCHMAR O. , TOMASKE M. , BALMER C. , SCHMITZ A. , BERGER F. , BAUERSFELD U. , WEISS M. ,   Working Group on Non‐invasive Haemodynamic Monitoring in Paediatrics
Published: July 2010

Purpose: To evaluate whether regional cerebral oxygenation (rSO2) by near‐infrared spectroscopy correlates with central venous (SvO2) or internal jugular (SjO2) oxygen saturation, and whether changes over time (Δ) in rSO2 (ΔrSO2) predict changes in SvO2 (ΔSvO2) and SjO2 (ΔSjO2).

Methods: The rSO2 values were measured using the INVOS 5100 cerebral oximeter in children undergoing interventional cardiac catheterization and were compared with the oxygen saturation of analysed central venous and internal jugular blood samples. Changes over time (Δ) were calculated as the difference between the values before and after catheter intervention for rSO2·(ΔrSO2), SvO2·(ΔSvO2) and SjO2·(ΔSjO2). Simple regression and Bland–Altman analysis were performed. Data are presented as median (range).

Results: Sixty patients aged 4.3 (0.2–16.0) years were investigated. A closer correlation was found between rSO2 and SvO2 (r=0.728, P<0.0001) than between rSO2 and SjO2 (r=0.665, P<0.0001). The bias between rSO2 and SvO2·(SjO2) was 0.17% (−0.60%), with limits of agreement from −15.5% to 15. 9% (−18.6–17.4%). The sensitivity/specificity for ΔrSO2 to indicate a fall in SvO2 or in SjO2 was 70.3%/65.2% and 68.6%/60.0%, respectively.

Conclusion: Neither absolute values nor changes in rSO2 using the INVOS 5100 allowed reliable estimation of SvO2 or SjO2 and their trends.
Drosophila NAT1, a homolog of the vertebrate translational regulator NAT1/DAP5/p97, is required for embryonic germband extension and metamorphosis
Authors: Yoshikane Nami , Nakamura Nao , Ueda Ryu , Ueno Naoto , Yamanaka Shinya , Nakamura Makoto
Published: July 2010

Translational regulation has been to shown to play major roles in the patterning of the early Drosophila embryo. The eIF4G family member NAT1/p97/DAP5 has been identified as a novel translational repressor. To genetically dissect the in vivo function of this unconventional eIF4G‐related translational regulator, Drosophila NAT1 (dNAT1) mutants were isolated using a reverse‐genetics approach. Four transposon insertion mutants and a deletion mutant affecting the dNAT1 locus were analyzed. Genetic complementation tests and germline rescue using a 12 kb dNAT1 genomic DNA fragment revealed these to be loss‐of‐function mutants. One P‐element insertion line, dNAT1GS1., shows severe embryonic lethality and abnormal germband extension. Abnormalities at metamorphosis were also found, including defective head eversion and salivary gland degeneration in the hypomorphic allele dNATex1. A phenotypic analysis of dNAT1 mutants suggests that dNAT protein plays a specific rather than general role in translational regulation.
Muscle Dysfunction Caused by a K
ATP
Channel Mutation in Neonatal Diabetes Is Neuronal in Origin
Authors: Clark Rebecca H. , McTaggart James S. , Webster Richard , Mannikko Roope , Iberl Michaela , Sim Xiu Li , Rorsman Patrik , Glitsch Maike , Beeson David , Ashcroft Frances M.
Published: July 2010

Brain Over Muscle

Mutations in the gene encoding the Kir6.2 subunit of the adenosine triphosphate (ATP)–sensitive potassium (K
ATP
) channel cause a specific type of neonatal diabetes in humans, known as iDEND, which is often accompanied by muscle weakness of unknown etiology. By studying mice expressing the mutant gene only in muscle or only in nerve,

Clark
et al.

(p.
458
, published online 1 July) found that the motor impairments originate from inappropriate activation of the channel in the central nervous system rather than in muscle. Patients with iDEND are often treated with sulphonylurea therapies that block K
ATP
channels in both brain and muscle, and these drugs can have adverse effects on heart muscle. Drugs with greater specificity for K
ATP
channels in the brain may thus be a safer option.
Single-Shot Readout of a Single Nuclear Spin
Authors: Neumann Philipp , Beck Johannes , Steiner Matthias , Rempp Florian , Fedder Helmut , Hemmer Philip R. , Wrachtrup Jörg , Jelezko Fedor
Published: July 2010

Probed But Not Perturbed

The processing and manipulation of quantum information holds great promise in terms of outperforming classical computers and secure communication. However, quantum information is delicate, and even reading the information is a destructive and probabilistic process requiring a number of measurements to home in on the information stored as a quantum state. For the nitrogen vacancy in diamond,

Neumann
et al.

(p.
542
, published online 1 July) show that these limitations can be eliminated. A measurement protocol was designed and implemented where the spin state of the nuclear spin of the vacancy could be mapped onto and read out from the surrounding electronic spins in a single-shot measurement nondestructively.
Ultrahigh Porosity in Metal-Organic Frameworks
Authors: Furukawa Hiroyasu , Ko Nakeun , Go Yong Bok , Aratani Naoki , Choi Sang Beom , Choi Eunwoo , Yazaydin A. Özgür , Snurr Randall Q. , O’Keeffe Michael , Kim Jaheon , Yaghi Omar M.
Published: July 2010

Network Approaches to Highly Porous Materials

Metal-organic frameworks (MOFs), in which inorganic centers are bridged by organic linkers, can achieve very high porosity for gas absorption. However, as the materials develop larger void spaces, there is also more room for growing interpenetrating networks—filling the open spaces not with gas molecules but with more MOFs.

Furukawa
et al.

(p.
424
, published online 1 July) describe the synthesis of a MOF in which zinc centers are bridged with long, highly conjugated organic linkers, but in which the overall symmetry of the networks created prevents formation of interpenetrating networks. Extremely high surface areas and storage capacities for hydrogen, carbon dioxide, and methane were observed.
Teachers guide to geologic trails in Delaware Water Gap National Recreation Area, Pennsylvania–New Jersey
Authors: Epstein Jack B.
Published: July 2010

The Delaware Water Gap National Recreation Area (DEWA) contains a rich geologic and cultural history within its 68,714 acre boundary. Following the border between New Jersey and Pennsylvania, the Delaware River has cut a magnificent gorge through Kittatinny Mountain, the Delaware Water Gap, to which all other gaps in the Appalachian Mountains have been compared. Proximity to many institutions of learning in this densely populated area of the northeastern United States (Fig. 1) makes DEWA an ideal locality to study the geology of this part of the Appalachian Mountains. This one-day field trip comprises an overview discussion of structure, stratigraphy, geomorphology, and glacial geology within the gap. It will be highlighted by hiking a choice of several trails with geologic guides, ranging from gentle to difficult. It is hoped that the “professional” discussions at the stops, loaded with typical geologic jargon, can be translated into simple language that can be understood and assimilated by earth science students along the trails. This trip is mainly targeted for earth science educators and for Pennsylvania geologists needing to meet state-mandated education requirements for licensing professional geologists. The National Park Service, the U.S. Geological Survey, the New Jersey Geological Survey, and local schoolteachers had prepared “The Many Faces of Delaware Water Gap: A Curriculum Guide for Grades 3–6” (Ferrence et al., 2003). Copies of this guide will be given to trip participants and can be downloaded from the GSA Data Repository1. The trip will also be useful for instruction at the graduate level. Much of the information presented in this guidebook is modified from Epstein (2006).
Physical Properties of Composites Near Percolation
Authors: Nan C.-W. , Shen Y. , Ma Jing
Published: July 2010

Dramatic changes in the physical properties of composites occur when filler particles form a percolating network through the composite, particularly when the difference between the properties of the constitutive phases is large. By use of electric conductivity and dielectric properties as examples, recent studies on the physical properties of composites near percolation are reviewed. The effects of geometric factors and intrinsic properties of the fillers and the matrix, and especially of the interface between fillers and matrix, on electric and dielectric properties near percolation are discussed. Contact resistivity at the interface is less desirable for enhancing electrical conductivity. By contrast, an interface with high resistivity suppresses tunneling between adjacent fillers and leads to percolative composites with higher dielectric constant but lower dielectric loss. This review concludes with an outlook on the future possibilities and scientific challenges in the field.
Teeth: Among Nature's Most Durable Biocomposites
Authors: Lawn Brian R. , Lee James J.-W. , Chai Herzl
Published: July 2010

This paper addresses the durability of natural teeth from a materials perspective. Teeth are depicted as smart biocomposites, highly resistant to cumulative deformation and fracture. Favorable morphological features of teeth at both macroscopic and microscopic levels contribute to an innate damage tolerance. Damage modes are activated readily within the brittle enamel coat but are contained from spreading catastrophically into the vulnerable tooth interior in sustained occlusal loading. Although tooth enamel contains a multitude of microstructural defects that can act as sources of fracture, substantial overloads are required to drive any developing cracks to ultimate failure—nature's strategy is to contain damage rather than avoid it. Tests on model glass-shell systems simulating the basic elements of the tooth enamel/dentin layer structure help to identify important damage modes. Fracture and deformation mechanics provide a basis for analyzing critical conditions for each mode, in terms of characteristic tooth dimensions and materials properties. Comparative tests on extracted human and animal teeth confirm the validity of the model test approach and point to new research directions. Implications in biomechanics, especially as they relate to dentistry and anthropology, are outlined.
Electromigration and Thermomigration in Pb-Free Flip-Chip Solder Joints
Authors: Chen Chih , Tong H.M. , Tu K.N.
Published: July 2010

Pb-free solders have replaced Pb-containing SnPb solders in the electronic packaging industry due to environmental concerns. Both electromigration (EM) and thermomigration (TM) have serious reliability issues for fine-pitch Pb-free solder bumps in the flip-chip technology used in consumer electronic products. We review the unique features of EM and TM in flip-chip solder bumps, emphasizing the effects of current crowding and Joule heating. In addition, the challenges to a better understanding of EM and TM in Pb-free solders are discussed. For example, the anisotropic nature of Sn microstructure in Pb-free solders can enhance the dissolution rates of Ni and Cu in solders driven by EM and TM.
Layer-specific strain analysis by speckle tracking echocardiography reveals differences in left ventricular function between rats and humans
Authors: Bachner-Hinenzon Noa , Ertracht Offir , Leitman Marina , Vered Zvi , Shimoni Sara , Beeri Ronen , Binah Ofer , Adam Dan
Published: July 2010

The rat heart is commonly used as an experimental model of the human heart in both health and disease states, assuming that heart function of rats and humans is alike. When studying a rat model, echocardiography is usually performed on sedated rats, whereas standard echocardiography on adult humans does not require any sedation. Since echocardiography results of sedated rats are usually inferred to alert humans, in the present study, we tested the hypothesis that differences in left ventricular (LV) function may be present between rats sedated by a low dose of ketamine-xylazine and alert humans. Echocardiography was applied to 110 healthy sedated rats and 120 healthy alert humans. Strain parameters were calculated from the scans using a layer-specific speckle tracking echocardiography program. The results showed that layer longitudinal strain is equal in rats and humans, whereas segmental strain is heterogeneous ( P < 0.05) in a different way in rats and humans ( P < 0.05). Furthermore, layer circumferential strain is larger in humans ( P < 0.001), and the segmental results showed different segmental heterogeneity in rats and humans ( P < 0.05). Radial strain was found to be homogeneous at the apex and papillary muscle levels in humans and heterogeneous in rats ( P < 0.001). Additionally, whereas LV twist was equal in rats and humans, in rats the rotation was larger at the apex ( P < 0.01) and smaller at the base ( P < 0.001). The torsion-to-shortening ratio parameter, which indicates the transmural distribution of contractile myofibers, was found to be equal in rats and humans. Thus, when evaluating LV function of sedated rats under ketamine-xylazine, it is recommended to measure the global longitudinal strain, LV twist, and torsion-to-shortening ratio, since no scaling is required when converting these parameters and inferring them to humans.
Aging impairs myocardial fatty acid and ketone oxidation and modifies cardiac functional and metabolic responses to insulin in mice
Authors: Hyyti Outi M. , Ledee Dolena , Ning Xue-Han , Ge Ming , Portman Michael A.
Published: July 2010

Aging presumably initiates shifts in substrate oxidation mediated in part by changes in insulin sensitivity. Similar shifts occur with cardiac hypertrophy and may contribute to contractile dysfunction. We tested the hypothesis that aging modifies substrate utilization and alters insulin sensitivity in mouse heart when provided multiple substrates. In vivo cardiac function was measured with microtipped pressure transducers in the left ventricle from control (4–6 mo) and aged (22–24 mo) mice. Cardiac function was also measured in isolated working hearts along with substrate and anaplerotic fractional contributions to the citric acid cycle (CAC) by using perfusate containing 13C-labeled free fatty acids (FFA), acetoacetate, lactate, and unlabeled glucose. Stroke volume and cardiac output were diminished in aged mice in vivo, but pressure development was preserved. Systolic and diastolic functions were maintained in aged isolated hearts. Insulin prompted an increase in systolic function in aged hearts, resulting in an increase in cardiac efficiency. FFA and ketone flux were present but were markedly impaired in aged hearts. These changes in myocardial substrate utilization corresponded to alterations in circulating lipids, thyroid hormone, and reductions in protein expression for peroxisome proliferator-activated receptor (PPAR)α and pyruvate dehydrogenase kinase (PDK)4. Insulin further suppressed FFA oxidation in the aged. Insulin stimulation of anaplerosis in control hearts was absent in the aged. The aged heart shows metabolic plasticity by accessing multiple substrates to maintain function. However, fatty acid oxidation capacity is limited. Impaired insulin-stimulated anaplerosis may contribute to elevated cardiac efficiency, but may also limit response to acute stress through depletion of CAC intermediates.
Plasma Visfatin Is Increased after High-Intensity Exercise
Authors: Ghanbari-Niaki Abbass , Saghebjoo Marziyeh , Soltani Raheleh , Kirwan John P.
Published: July 2010

Background/Aims: Visfatin is a newly characterized protein that is highly expressed in visceral adipose tissue and may play a role in insulin resistance. We investigated the effects of repeated short bouts of high-intensity exercise on plasma visfatin and related metabolic responses. Methods: Six young, physically fit men (22.8 ± 2.3 years; 78.5 ± 2.3 kg; and body mass index 22.1 ± 1.2) performed a single session of a running-based anaerobic sprint exercise (7 sets of 6 × 35 m every 10 s, with 1 min rest between sets). Venous blood samples were collected before, immediately after, and 45 and 90 min after exercise to assess plasma visfatin, insulin, glucose, lactate and glutathione responses. Results: After adjustment for postexercise changes in plasma volume, the data indicate a significant increase in plasma visfatin (12.5 ± 2.0 vs. 26.6 ± 3.9 ng/ml, p < 0.02), insulin (p < 0.05), and glucose (p < 0.002) concentrations, and homeostasis model assessment of insulin resistance (p < 0.02), immediately after the exercise session. At 45 min of recovery, all metabolic measures, with the exception of lactate, had returned to baseline levels. Conclusion: The elevation in plasma visfatin, together with increased plasma glucose and insulin concentrations immediately after high-intensity exercise, may sensitize tissues for postexercise glucose uptake and glycogen restoration. Our results also support a temporary and early postexercise anorexigenic metabolic state.
An Update and Practical Guide to Renal Stone Management
Authors: Johri Nikhil , Cooper Bruce , Robertson William , Choong Simon , Rickards David , Unwin Robert
Published: July 2010

Renal stone disease covers kidney and lower urinary tract stones caused by a variety of conditions, including metabolic and inherited disorders, and anatomical defects with or without chronic urinary infection. Most cases are idiopathic, in which there is undoubtedly a genetic predisposition, but where environmental and lifestyle factors play an important role. Indeed, it is becoming apparent that renal stone disease is often part of a larger ‘metabolic picture’ commonly associated with type 2 diabetes, obesity, dyslipidaemia, and hypertension. Renal stone disease is a growing problem in the UK (and other developed and developing populations) with a cross-sectional prevalence of ∼1.2%. This means that there are currently ∼720,000 individuals with a history of kidney stones in the UK. Almost 40% of first-time stone formers will form a second stone within 3 years of the first episode if no prophylactic measures are instituted to prevent stone recurrence, since removal or disintegration of the first stone does not treat the underlying cause of stones in the majority of patients. The age of onset is getting younger and the sex ratio (until recently more men than women) is becoming almost even. Metabolic screening remains an important part of investigating renal stone disease, but to the disappointment and frustration of many doctors, medical treatment is still essentially pragmatic, except perhaps in cystinuria, and to a limited extent in primary hyperoxaluria (if pyridoxine-sensitive); although newer treatments may be emerging. This review summarizes current thinking and provides a practical basis for the management of renal stone disease.
The Effects of Vitamin D Therapy on Left Ventricular Structure and Function – Are These the Underlying Explanations for Improved CKD Patient Survival?
Authors: Covic Adrian , Voroneanu Luminita , Goldsmith David
Published: July 2010

Cardiovascular disease is a major cause of death among patients with chronic kidney disease and vitamin D deficiency is a common problem also among these patients. Abnormalities in left ventricular size and function are frequent, as they are encountered in 70–80% of incident dialysis patients. These alterations develop early in the course of renal disease and their prevalence progresses in parallel with the decline in renal function. This process of left ventricular dilatation with compensatory hypertrophy continues after the institution of dialysis therapy, especially in the first year. The main factors responsible for the progression of left ventricular hypertrophy (LVH) are considered to be blood pressure and anemia, and in patients receiving hemodialysis, the arteriovenous fistula, volume overload and abnormalities in mineral metabolism. This additional potential set of factors related to LVH – mineral and bone metabolism – is intriguing and begs an immediate question: by what possible mechanism can these factors be linked to cardiac morphology? Recent observational studies have indeed indicated that vitamin D treatment was associated with a significant reduction of cardiovascular death among dialysis patients, and a reduction in LVH; in contrast, other studies suggested that excess vitamin D contributes to risk of hypercalcemia and vascular calcification, which is associated with reduced survival and morbidity. This review examines the evidence linking vitamin D with cardiac structure and function.
Ranking the Harm of Alcohol, Tobacco and Illicit Drugs for the Individual and the Population
Authors: van Amsterdam Jan , Opperhuizen Antoon , Koeter Maarten , van den Brink Wim
Published: July 2010

Drug policy makers continuously face a changing pattern of drug use, i.e. new drugs appear on the market, the popularity of certain drugs changes or drugs are used in another way or another combination. For legislative purposes, drugs have mostly been classified according to their addictive potency. Such classifications, however, lack a scientific basis. The present study describes the results of a risk assessment study where 19 recreational drugs (17 illicit drugs plus alcohol and tobacco) used in the Netherlands have been ranked by a Dutch expert panel according to their harm based on the scientific state of the art. The study applies a similar approach as recently applied by Nutt et al. [Lancet 2007;369:1047–1053], so that the results of both studies could be compared. The harm indicators scored are acute and chronic toxicity, addictive potency and social harm. The aim of this study is to evaluate whether the legal classification of drugs in the Netherlands corresponds with the ranking of the drugs according to their science-based ranking of harm. Based on the results, recommendations are formulated about the legal classification of recreational drugs at national and international level which serves a rational approach for drug control.
Viral Fusion Peptides Induce Several Signal Transduction Pathway Activations That Are Essential for Interleukin-10 and Beta-Interferon Production
Authors: Vitiello Mariateresa , Finamore Emiliana , Falanga Annarita , Raieta Katia , Cantisani Marco , Galdiero Francesco , Pedone Carlo , Galdiero Marilena , Galdiero Stefania
Published: July 2010

Objectives: The deciphering of intracellular signaling pathways that are activated by the interaction between viral fusion peptides and cellular membranes are important for the understanding of both viral replication strategies and host defense mechanisms. Methods: Fusion peptides of several enveloped viruses belonging to different virus families were prepared by standard 9-fluorenylmethoxycarbonyl polyamine solid-phase synthesis and used to stimulate U937 cells in vitro to analyze the phosphorylation patterns of the signaling pathways (PKC, Src, Akt, and MAPK pathways). Immunoprecipitation and Western blotting were carried out by using phosphospecific antibodies. All samples were also assayed for the presence of IL-10 and IFN-β by ELISA and activation of nuclear factors (AP-1 and NF-ĸB). Results: We have demonstrated that hydrophobic domains of fusion proteins are able to induce several transduction pathways that lead to cytokine (IFN-β and IL-10) production, an event that appears to be dependent on early activation of AP-1 and NF-ĸB. Conclusions: The results obtained on the signaling activity of fusion peptides from different viruses enabled us to shed some light on the complex mechanism of viral entry and more precisely we focused on the exact signaling event induced by hydrophobic domains characteristic of fusion peptides interacting with the cell membrane.
Rotavirus Genotypes in Costa Rica, Nicaragua, Honduras and the Dominican Republic
Authors: Bourdett-Stanziola Lurys , Ortega-Barria Eduardo , Espinoza Felix , Bucardo Filemon , Jimenez Carlos , Ferrera Annabelle
Published: July 2010

In this study, 574 stool samples from children with gastroenteritis were obtained from different hospitals in Costa Rica, Honduras, Nicaragua and the Dominican Republic during 2005–2006. Diarrhea stool samples were analyzed for rotavirus by ELISA and typed by the RT-PCR-based method. Unusual strains were detected: G1P6, G2P8, G3P6, G9P4 and mixed infections. Recent studies have indicated that unusual human rotavirus strains are emerging as global strains, which has important implications for effective vaccine development. In this context, the next generation of rotavirus vaccines will need to provide adequate protection against diseases caused not only by mixed infections, but also by unusual G/P combinations.