bluuebunny/crossref_metadata_2025 huggingface dataset:
The Dynamic Behavior of the Real Exchange Rate in Sticky Price Models
Authors: Steinsson Jón
Published: March 2008

Existing empirical evidence suggests that real exchange rates exhibit hump-shaped dynamics. I show that this is a robust fact across nine large, developed economies. This fact can help explain why sticky price business cycle models have been unable to match the persistence of the real exchange rate. I show that, in response to a number of different real shocks, a two-country sticky price business cycle model yields hump-shaped dynamics for the real exchange rate. The hump-shaped dynamics generated by the model are a powerful source of endogenous persistence that allows the model to match the long half-life of the real exchange rate. (JEL F31)
Bureaucrats or Politicians? Comment
Authors: Kojima Fuhito
Published: March 2008

Alesina and Tabellini (2007) investigate the normative criteria for allocating policy tasks to bureaucrats versus politicians. While they establish criteria with respect to a number of parameters, they do not give a criterion with respect to the degree of imperfect monitoring. We establish an unambiguous criterion about imperfect monitoring. (JEL D72, D73)
Conjugation and optoelectronic properties of acetylenic scaffolds and charge-transfer chromophores
Authors: Kivala Milan , Diederich François
Published: March 2008

Our group started a research program in acetylene chemistry in 1987; since then, an intense research effort led to a fascinating journey into acetylenic scaffolding, aimed at exploring conjugative and optoelectronic properties of acetylenic chromophores. This journey included the generation of a unique molecular construction kit for acetylenic scaffolding, consisting of (E)-1,2-diethynylethenes [DEEs, (E)-hex-3-ene-1,5-diynes], tetraethynylethenes (TEEs, 3,4-diethynylhex-3-ene-1,5-diynes), chiral 1,3-diethynylallenes (DEAs, hepta-3,4-diene-1,6-diynes), 1,4-di and 1,1,4,4-tetraethynylbutatrienes, chiral trialkynylmethanes, and 1,1,2,2-tetraethynylethanes. These building modules were subsequently applied to the synthesis of carbon-rich architectures extending into one, two, and three dimensions. They include multinanometer-long monodisperse oligomers as models for infinite acetylenic polymers, molecular switches, perethynylated dehydroannulenes, expanded radialenes, and radiaannulenes, and an octamethoxy-substituted expanded cubane with a central C56core. Donor-substituted cyanoethynylethenes (CEEs) and 1,1,4,4-tetracyanobuta-1,3-dienes (TCBDs) were introduced as new push-pull chromophores featuring intense intramolecular charge-transfer (CT) interactions. Dendritic multivalent CT chromophores were constructed using atom-economic, "click"-like reactions, and these systems were shown to behave as "molecular batteries", featuring exceptional electron uptake and storage capacity. The research finally led to the development of an unprecedented cascade reaction for the preparation of dendritic and oligomeric donor-acceptor (D-A) molecules. New [AB]-type oligomers become accessible in domino reactions involving repetitive sequences of [2+2] cycloadditions of tetracyanoethylene (TCNE) and tetrathiafulvalene (TTF) to polyynes, followed by retro-electrocyclizations.
Heterophenes revisited
Authors: Luh Tien-Yau , Lin Hsin-Chieh , Chou Chih-Ming
Published: March 2008

By employing the furan annulation protocol, a new series of furan-containing teraryl [n.2]cyclophenes (n= 2-6 and 12) are prepared. These cyclophenes exhibit charge-transfer character in the absorption spectra and unusually large Stokes shifts in the emission spectra. They have neither particularly strong electron-donating moieties nor electron-withdrawing groups, but exhibit unusual second-order nonlinear optical (NLO) properties. The π-systems in teraryl system and in the bridging double bond are highly twisted. Interaction between these twisted π-systems may account for the significant enhancement in hyperpolarizability. Thiophene analog behaved similarly. The five-membered heteroaromatic rings may not only serve as electron donors, but also may accommodate the appropriate geometry to enable the interactions between the oligoaryl systems and the double bond leading to unusual photophysical and NLO properties.
Photochromic diarylethene as an information processing unit: Magnetic and electric switching
Authors: Matsuda Kenji
Published: March 2008

Photochromic compounds reversibly change not only the absorption spectra but also their geometrical and electronic structures. This principle can be applied for the photoswitching of the physical properties of the molecular materials. In particular, photoswitching of the flow of information through the molecule is interesting because information processing using molecular devices is attracting interest in the molecular electronics field. The photoswitchings of the magnetic exchange interaction and the electrical conductance using photochromic diarylethene are described.
Novel aromatic species containing group 14 atoms
Authors: West Robert
Published: March 2008

The dianions of tetraphenylsilole and tetraphenylgermole behave as aromatic species, as shown by the equalization of C-C bond lengths in these rings and by nucleus-independent chemical shift (NICS) calculations. Similarly, the dianions of 9-silafluorene and 9-germafluorene are aromatic. In the latter species, the heteroatom five-membered rings are more aromatic than the attached benzene rings. Also to be recognized as aromatically stabilized compounds are the stable unsaturated diiminocarbenes, diiminosilylenes, and diiminogermylenes. Evidence for the aromatic delocalization in these molecules comes from NMR, NICS calculations, Raman spectroscopy, isodesmic molecular orbital (MO) calculations, and calculated isomerization stabilization energies. From the presently available evidence, the aromaticity appears to alternate, with C > Ge > Si, going down group 14.
Self-assembly and properties of low-dimensional nanomaterials based on π-conjugated organic molecules
Authors: Lv Jing , Liu Huibiao , Li Yuliang
Published: March 2008

Building supramolecular architectures with well-defined shapes and functions is of great importance in materials science, nanochemistry, and biomimetic chemistry. In recent years, we have devoted much effort to the construction of well-defined supramolecular structures through noncovalent forces such as hydrogen bonding, π-stacking, metal-ligand bonds, and hydrophilic and hydrophobic interactions, with the aid of functional building blocks. The morphologies and their physical properties were studied, and new methods for the construction of one-dimensional nanoscale structures have been developed. In this review, we summarize our recent studies on the design and synthesis of the supramolecular systems, as well as the physical properties of nanoscale structures.
Sind winkelstabile Plattensysteme mit elastischen Eigenschaften für die Stabilisierung der Oberarmkopffraktur vorteilhaft? / Eine in-vitro biomechanische Untersuchung
Authors: Hessmann M. H , Sternstein W , Mehler D , Korner J , Hofmann A , Rommens P.M
Published: March 2008

Winkelstabile Platten werden mit zunehmender Häufigkeit zur Stabilisierung von Oberarmkopfbrüchen verwendet. Rigide Implantate führen bei osteoporotischen Knochenverhältnissen u. U. aber häufiger zum Versagen. Um den Effekt der Implantatelastizität zu beurteilen wurden in einer in-vitro Studie die biomechanischen Eigenschaften eines rigiden und eines elastischen winkelstabilen Plattensystems vergleichend analysiert. An 8 Humeruspaaren wurde eine instabile subkapitale Fraktur simuliert. Die Proben wurden axial- und torsions-belastet. Analysiert wurden die Steifigkeit, das Setzverhalten unter Dauerlast und die Versagensbelastung.

Das elastische Plattensystem kennzeichnete sich durch eine geringere Torsionssteifigkeit und eine größere Verformung unter Axial- und Torsionsbelastung. Die Proben versagten früher als beim rigiden Plattenystem.

Unter biomechanischen Gesichtspunkten bieten Implantate mit elastischen Eigenschaften am Oberarmkopf somit keine Vorteile.

 

There is a recent interest for the use of angle-fixed plates in the management of proximal humerus fractures. Rigid implants might be associated with an increased risk of cutting-out. In order to analyse the potential beneficial effects of the implant elasticity on fracture fixation, the biomechanical properties of a rigid and an elastic angle-fixed plating system were assessed in an experimental study. An unstable fracture of the surgical neck was created in 8 pairs of human humeri. Specimens were subjected to axial loading and torque. Stiffness, subsidence and load to failure were assessed.

The implant with elastic properties was characterized by a lower torsional stiffness and a higher subsidence during axial loading and torque. This implant failed at lower loads than the rigid implant did.

Elastic implant properties of angle-fixed plates have shown not to be advantageous for the management of fractures of the proximal humerus.
Changes in the Population Ecology of Hatchery and Wild Coho Salmon in the Strait of Georgia
Authors: Beamish R. J. , Sweeting R. M. , Lange K. L. , Neville C. M.
Published: March 2008

An analysis of the results of a 10‐year study of the population ecology of juvenile hatchery and wild coho salmon Oncorhynchus kisutch in the Strait of Georgia produced new information about the interannual and interseasonal fluctuations in abundance and marine survival. A decline in the percentage of hatchery coho salmon was related to declines in hatchery fish abundance and marine survival; wild coho salmon abundance was more stable. The declining marine survival of hatchery coho salmon appeared to be related to a fixed average date of release from hatcheries and a possibility of earlier prey production. The relatively stable abundance of wild coho salmon may relate to a natural trend toward earlier ocean entry dates. Oscillations in hatchery coho salmon percentage and abundance were related to oscillations in abundance of juvenile pink salmon O. gorbuscha. The impact of oscillating density affected marine survival of hatchery coho salmon more than that of wild coho salmon. Marine survival and abundance of hatchery and wild coho salmon in July were positively related to average fork length, indicating that growth within the first few months after ocean entry affected marine survival. However, absolute size was not important, as wild coho salmon were consistently smaller than hatchery coho salmon. Wild coho salmon responded to conditions in the marine ecosystem differently than hatchery coho salmon, as relationships among growth, survival, and abundance were apparent for wild coho salmon earlier in the year than for hatchery fish. The length increase between July and September was inversely related to marine survival, suggesting that fish that were larger in July grew less and survived better because they were storing more lipids than smaller coho salmon. The study indicated that a more experimental management strategy is needed for both hatchery and wild coho salmon.
Formation of Underwater Cuttings Piles in Offshore Drilling
Authors: Fang Qian , Guo Boyun , Ghalambor Ali
Published: March 2008

The discharge of drill cuttings to the seabed can significantly reduce offshore drilling cost. However, the formation of cuttings piles on the seabed near the rigsite can present problems for drilling and production operations. When the problem is likely to occur in the areas of low-current velocity, the cuttings are not discharged to seabed, but ground and injected to formation or transported onshore for disposal, which increases drilling cost. It is highly desired to have an accurate method to predict the location and configuration of the cuttings piles in the design stage of well drilling. This paper presents a solution to the problem.

Starting from Newton's second law of motion, a mathematical model has been developed in this study to predict the location, configuration, and characteristics of cuttings piles. Factors considered include water depth, current velocity, cuttings properties (e.g., size distribution, density, and sphericity), and water properties (such as density and viscosity). This mathematical model has been computerized. It provides well planners a useful tool for predicting the characteristics of cuttings piles during drilling. Application of the tool can reduce the cost of drilling through better handling of drill cuttings such as discharging to water vs. injecting into the formation.
New Technology Improves Performance of Viscoelastic Surfactant Fluids
Authors: Crews James B. , Huang Tianping , Wood W. Russell
Published: March 2008

For a number of years, viscoelastic surfactant (VES) fluids have been used for a variety of stimulation treatment applications, including hydraulic fracturing, acid diverting, and gravelpacking. VES fluid systems typically offer higher-retained permeability and conductivity of the formation sand and proppant pack than polymeric systems. However, preliminary cost, a 200°F temperature limit, excessive leakoff, and no internal breaker mechanism for dry gas applications have limited VES use.

New VES fluid technology has been developed that substantially improves product performance and cost effectiveness. The temperature range has been extended to 300°F by using newly developed VES stabilizer technology. The system works with high-density brines up to 14.4 ppg. Internal breakers have been developed that permit a controlled viscosity break from ambient to 300°F. Laboratory tests have determined that an internally broken fluid rapidly achieves >90% returned permeability and conductivity of the formation sand and proppant pack without the presence or need for contacting hydrocarbons. Fluid loss-control technology has been developed that reduces VES fluid leakoff similar to wall-building fluids, but without filtercake damage.

This paper discusses the development of the new VES system chemistry and its properties. The paper also addresses the merits of a viscous fluid that can work in a variety of base fluids for high-pressure applications, such as managing surface-treating pressure or for gas-hydrate inhibition in deep gas or deepwater environments. Breaker technology discussion addresses the ability to ensure and enhance VES fluid-viscosity breaking. Fluid loss-control technology effective to at least 2,000 millidarcies (mD) is presented. This paper also presents rheological, return permeability and conductivity, fluid loss control, treating pressure, and financial results.
Presence of shrubs influences the spatial pattern of soil seed banks in desert herbaceous vegetation
Authors: Li Feng‐Rui
Published: March 2008

Question: Do shrubs influence the spatial pattern of soil seed banks in herbaceous vegetation and are these effects influenced by wind direction, sampling position (windward vs leeward sides of the shrub) and distance from the shrub?

Location: Horqin desert in eastern Inner Mongolia, China.

Methods: A pioneer shrub, Artemisia halodendron, occurring in a mobile sandy habitat was used as a case study. Species composition and abundance of the seed bank and established herbaceous vegetation around six target shrubs were sampled along transects aligned to the four main wind directions and at 0.5, 1, 2, 3, 4.5 and 6 m from the shrub base on both windward and leeward sides of a transect.

Results: The presence of shrubs significantly modified the spatial pattern of seed deposition, but effects varied with wind direction, sampling position and distance from the shrub. More seeds were deposited on the leeward side than on the windward sides in all four transects, especially on transects with the most prevailing wind directions. Shrubs also caused a marked variation in seed deposition across sampling locations; this effect was more pronounced on the leeward side of transects with the most prevailing wind directions, suggesting the mean range of the shrub's influence is within ca. 2 m.

Conclusions: The study shows clear evidence of shrubs as a source of spatial heterogeneity in seed availability in the herbaceous layer. Shrub presence effects were strongly influenced by complex interactions between wind direction, sampling position, and distance from the shrub.
Tissue Engineering
Authors: Jagur‐Grodzinski Joseph
Published: March 2008

The concept of tissue engineering (TE) was born when Vacanti and Langer suggested that living cells may form
in vitro
, at appropriate conditions, structures identical with those they form in live bodies. Tissue engineering is a fast growing branch of biomedical engineering. It currently consists of several branches. Seeding and culturing cells on scaffolds, which imitate extracellular matrix (ECM), is the basis of the most commonly used method. Scaffolds are prepared from various natural and synthetic polymers. Another variant of TE involves injection of gels that form scaffolds
in situ
. Acellular scaffolds may also be inserted
in vivo
. They mobilize cells from the adjacent tissues, from circulating body fluids, or stem cell sources. The above mentioned methods eliminate the
in vitro
stage of TE procedures. Another branch of TE is called cell‐sheet engineering (CSE). It involves culturing cell sheets on a surface of a polymer, whose structure undergoes sudden transition at a certain critical temperature (
T
tr
). Cells are cultured at
T
>
T
tr
. However, when a sheet is formed it separates spontaneously from the supporting surface when the temperature is decreased <
T
tr
. Sheets thus formed can be harvested without damaging cell–cell or cell–ECM interactions. The CSE is particularly suitable for TE of liver and heart, since they consist of cells loosely associated with ECM.

Materials used for formation of scaffolds and methods used for their preparation are described in some detail. Techniques, eg, rapid prototyping (RP) and photopattering, are discussed. Inverse RP, as well as the engineering of scaffolds surfaces, is also mentioned. The operation mechanism of various bioreactors for TE and their effect on the properties of the engineered tissues are reviewed.
Acrylic Elastomers, Survey
Authors: Starmer Philip H. , Wolf Fred R.
Published: March 2008

Acrylic elastomers have the ASTM designation ACM for polymers of ethyl acrylate and other acrylates, and ANM for copolymers of ethyl or other acrylates with acrylonitrile. In both cases, the M indicates a polymer having a saturated chain of the polymethylene type. The combination of a saturated backbone with polar side chains results in a class of polymers with very good resistance to heat and oil, including oils containing hypoid additives. Acrylic elastomers also have good resistance to sunlight and ozone. Ethylene–acrylic elastomers are discussed in a separate article.

The first acrylic elastomers were homopolymers of either ethyl acrylate or methyl acrylate. Because these had limited utility, particularly for vulcanized applications, various copolymer modifications were developed to improve performance, and there evolved a division of monomers into two types:backbone monomers, which comprise the principal proportion of the monomers and determine the physical and chemical properties of the polymer, andcure‐site monomers, which are incorporated to the extent of 1–5% to introduce reactive sites for subsequent cross‐linking reactions.

Emulsion and suspension polymerization are the important methods for preparing the elastomers. Their rheological characteristics require processing that addresses contamination more than for other types. Fairly rigid processing is required. The monomers from which these elastomers are prepared have varying degrees of toxicity. Because of the wide property range, the acylic elastomers have many application, eg, coatings, textiles, automotive products, adhesives, paper, and agriculture.
Palladium(0) Nanoparticles on Glass‐Polymer Composite Materials as Recyclable Catalysts: A Comparison Study on their Use in Batch and Continuous Flow Processes
Authors: Mennecke Klaas , Cecilia Raul , Glasnov Toma N. , Gruhl Susanne , Vogt Carla , Feldhoff Armin , Vargas M. A. Larrubia , Kappe C. Oliver , Kunz Ulrich , Kirschning Andreas
Published: March 2008

Palladium particles were generated by reduction of palladate anions bound to an ion exchange resin inside microreactors. The size and distribution of the palladium particles differed substantially depending on the degree of cross‐linking and the density of ion exchange sites on the polymer/glass composites, the latter parameter having a larger influence than the former. The polymer phase of the composite materials was used for the loading with clusters composed of palladium particles which are 1 to 10 nm in diameter. The reactivity and stability of six different palladium‐doped polymer/glass composite samples for transfer hydrogenations was investigated both under conventional and microwave heating in the batch mode as well as under continuous flow conditions using the cyclohexene‐promoted transfer hydrogenation of ethyl cinnamate as a model reaction. Regarding the heating method it was found that catalysts that are composed of larger metal particles perform better under microwave irradiating conditions whereas samples with smaller particle sizes perform better under conventional heating. Comparing batch experiments with flow‐through experiments the latter technique gives better conversion. Reusability was better in microwave heated experiments than in traditional heating.
Half‐Sandwich Scorpionate Vanadium, Iron and Copper Complexes: Synthesis and Application in the Catalytic Peroxidative Oxidation of Cyclohexane under Mild Conditions
Authors: Silva Telma F. S. , Alegria Elisabete C. B. A. , Martins Luísa M. D. R. S. , Pombeiro Armando J. L.
Published: March 2008

The new half‐sandwich scorpionate complexes [hydridotris(1‐pyrazolyl)methane]vanadium trichloride, ([VCl3{HC(pz)3}] 1 (pz=pyrazolyl), [tris(1‐pyrazolyl)methanesulfonate]vanadium trichloride, [VCl3{SO3C(pz)3}] 2, [hydrido(1‐pyrazolyl)methane]iron dichloride, [FeCl2{HC(pz)3}] 3, lithium [tris(1‐pyrazolyl)methanesulfonate]dichloroferrate, Li[FeCl2{SO3C(pz)3}] 4, and [tris(1‐pyrazolyl)methanesulfonate]copper chloride, [CuCl{SO3C(pz)3}] 5 were synthesized, characterized and shown to act, as well as the related (tripyrazolylmethane)copper dichloride, [CuCl2{HC(pz)3}] 6, as selective catalysts (or catalyst precursors) for the peroxidative oxidation (with hydrogen peroxide) of cyclohexane to cyclohexanol and cyclohexanone, under mild conditions (at room temperature and using an aqueous solution of H2O2). The iron complexes are the most active ones (reaching TON values up to ca. 690), the effects of a variety of factors are reported and the reaction is shown to proceed via both C‐ and O‐centred radical mechanisms, conceivably involving a metal‐based oxidant.
Highly Efficient Copper(I) Iodide‐Tolyl‐BINAP‐Catalyzed Asymmetric Conjugate Addition of Methylmagnesium Bromide to α,β‐Unsaturated Esters
Authors: Wang Shun‐Yi , Lum Tze‐Keong , Ji Shun‐Jun , Loh Teck‐Peng
Published: March 2008

A highly efficient asymmetric conjugate addition of methylmagnesium bromide (MeMgBr) to α,β‐unsaturated esters catalyzed by copper(I) iodide‐tolyl‐BNIP (CuI‐Tol‐BINAP) is described.
CFD simulation of flow in vortex diodes
Authors: Kulkarni A. A. , Ranade V. V. , Rajeev R. , Koganti S. B.
Published: March 2008

Vortex diodes are used as leaky nonreturn valves in applications, where it is desirable to avoid valves with moving parts. Despite their use in practice for several decades, no detailed analysis of the flow inside the vortex diodes is available. A strategy was derived for the CFD simulations of the vortical flow in diodes. A good agreement was seen between pressure drop (ΔP) across the inlet‐outlet ports from CFD simulations, and the experimental data for five diode sizes. The simulations showed that in the reverse flow situation tangential velocity was dominant and resulted in conservation of angular momentum in the chamber until it reaches the axial exit port. This vortical motion induced a significant pressure drop (ΔPr). The axial velocity gradient over the chamber cross‐section helps in inducing relaminarization of the flow. In the forward flow mode, the fluid gets distributed radially over the chamber and exits through the tangential port, yielding low ΔPf. The analysis showed that the performance of a diode is strongly affected by diode geometry, size, aspect ratio, nozzle configuration and Reynolds number. Among different configurations, the nozzles with entry port size equal to diode yielded higher diodicity. Simulations showed that using angle of divergence for diffuser sections of nozzles of the order of 7° exhibited higher diodicity than smaller angles. It was also observed that at higher flow rates significantly higher diodicity was obtained using axial nozzles with larger radius of curvature for expander section. The modeling methodology and results presented will be useful for evolving better designs of vortex diodes. © 2008 American Institute of Chemical Engineers AIChE J, 2008
WOx‐CeO2 and WOx‐Nb2O5 catalysts deactivation during hexane isomerization
Authors: Mamede A.‐S. , Payen E. , Granger P. , Florea M. , Pârvulescu V. I.
Published: March 2008

Two series of WOx‐CeO2 catalysts containing 10, 12, and 15 wt % W were prepared by co‐precipitation and incipient wetness impregnation using a reported procedure. WOx‐Nb2O5 catalysts with the same amount of W were prepared by co‐precipitation starting from an aqueous solution of ammonium niobium oxalate and ammonium metatungstate with ammonia, until reaching pH 7. After calcining for 3 h in static air at 973 K, the deactivation of the catalysts was investigated using isomerization of hexane as probe reaction at temperatures in the range 393–513 K, both in the absence and in the presence of hydrogen. In‐situ Raman spectra during deactivation were recorded as well. The deactivation rate was fitted by an empirical Voorhies equation: R = m
t−n, where the values of n correlated very well with the mass loss determined from TG analysis. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Hydrodynamics of the mixing chamber in RIM: PIV flow‐field characterization
Authors: Santos Ricardo J. , Erkoç Ertugrul , Dias Madalena M. , Teixeira André M. , Lopes José Carlos B.
Published: March 2008

The flow‐field in a Reaction Injection Moulding, RIM, machine mixing chamber was characterized using the Particle Image Velocimetry (PIV) technique. This study covered the industrial range of Reynolds numbers, Re, for the RIM process, from 100 to 500, setting the overall trends of the flow‐field in that range, with particular focus on the flow regime transition range of 100 ≤ Re
≤ 150. The instantaneous 2D velocity vector maps were obtained with PIV in a plane containing the chamber and injectors axis. From instantaneous velocity data, the following quantities were computed: the probability density functions, the average velocity, and turbulence intensity. The present study sheds additional light into the transition of flow‐field regime that marks the onset of mixing on RIM, and also into the mixing mechanisms and respective underlying flow‐field features. © 2008 American Institute of Chemical Engineers AIChE J, 2008
What can variation in stature reveal about environmental differences between prehistoric Jomon foragers? Understanding the impact of systemic stress on developmental stability
Authors: Temple Daniel H.
Published: March 2008

This study reconstructs patterns of stress and phenotypic variation in prehistoric Japan. Greater evidence for stress is indicated by elevated enamel hypoplasia frequency among Jomon foragers from western compared to eastern Japan. Geographic variation in stress between Jomon people is related to plant‐based diets and resource scarcity in western Japan. The hypothesis that Jomon people from western Japan had shorter stature than those from the east is, therefore, tested. Relationships between individual stature, geographic location, and enamel hypoplasia presence/absence are also explored. In addition, increased population density and reliance on plant foods are observed during the Late/Final Jomon period in western Japan. A second hypothesis proposing shorter stature for Late/Final Jomon people compared to those from the Middle Jomon period is tested. Statistically significant differences in stature between males and females from eastern and western Japan were not observed. Individual relationships between enamel hypoplasia and stature were rejected. Stature decreased significantly over time in western Japan. It is possible that stature between the eastern and western Jomon did not differ because the western Jomon experienced catch up growth after childhood stress episodes. It is also likely that variation in stress between the two groups was not severe enough to warrant stature reduction. Decreases in stature through time in western Japan are related to increased exposure to chronic infection and dietary stress. Overall, these results indicate that enamel hypoplasia frequencies provide an adequate index of general stress but may fail to predict the impact of stress on the human phenotype. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Rural urban differences of cardiovascular disease risk factors in adult Asian Indians
Authors: Das Mithun , Pal Susil , Ghosh Arnab
Published: March 2008

The prevalence of cardiovascular disease (CVD) risk factors in “People of Indian Origin” (PIO) is exceedingly high and strong relationships among elevated blood pressure, increased levels of lipoproteins, visceral obesity, physical inactivity and subsequent high occurrence of coronary heart disease, type 2 diabetes mellitus etc., were evident in many studies. Increasing urbanization with effective changes in lifestyles could be attributed to explain this exaggerated rate. The present community based cross‐sectional investigation was aimed to identify rural‐urban differences in prevalence of risk factors of CVD in the adult Asian Indians. A total of 350 adult (30 years and above) individuals (184 males and 166 females) belong to urban (n = 193, males = 104, and females = 89) and rural (n = 157, males = 80, and females = 77) areas participated in the study. Anthropometric measures, lipids profiles, fasting blood glucose and blood pressure measures were obtained from participants. The mean body mass index (kg/m2) for male and female was 22.37 ± 4.09 and 23.20 ± 4.37, respectively. There existed significant differences for anthropometric, metabolic, and blood pressure variables between rural and urban areas. Habitat (rural vs. urban) had significant impact on central adiposity, lipids, lipoproteins, and blood pressure measures even after adjusted for age and sex. Overall, 84.3% of females had lower HDL level compared with only 20.1% in males. It was also observed that the prevalence of metabolic syndrome was 56.2% in urban females compared with 36.4% in rural females. Effective urbanization and or modernization seem to influence CVD risk factors and warrants intervention as early as adulthood to check this menace. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Relation of ratio indices of anthropometric measures to obesity in a stunted population
Authors: Judd Suzanne E. , Ramirez‐Zea Manuel , Stein Aryeh D.
Published: March 2008

The ratios of anthropometric measures are used to estimate obesity while controlling for allometric scaling. A good index should be uncorrelated with its denominator; this often requires exponentiation of the denominator. The stability of the derived exponents across populations is not known. We obtained subscapular (SUBS) and triceps (TRI) skinfolds, weight (WT), height (HT), waist circumference (WC), fat mass (FM), and fat‐free mass (FFM) in a population of Guatemalan adults [height 1.63 ± 0.06 m (868 males); 1.51 ± 0.06 m (1047 females)]. We derived exponents for the indices WT/HTP, SUBS/TRIP, TRI/SUBSP, WC/HTP, FM/WTP, and FM/FFMP such that the ratios were free from association with their denominators. The derived exponents were (Men: SUBS/TRI0.88, FM/WT2.69, FM/FFM2.86, WC/HT0.68, and WT/HT2.17; Women: SUBS/TRI0.93, FM/WT2.01, FM/FFM3.37, WC/HT0.47, WT/HT2.03). For all examined indices the derived exponents differed (P < 0.05) from 1 and differed (P < 0.05) between men and women. The exponents for the men also differed from those previously published for Brazilian men (JCK Wells and CG Victora [2005]: Int J Obes 29:483–489). The derived indices were not more strongly correlated with adiposity than were simple unexponentiated ratios. Although exponentiation of the denominator eliminates the association of index with its denominator, the resulting exponents lack generalizability across populations, especially those where stunting remains prevalent. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Low digit ratio (2D:4D) is associated with delayed menarche
Authors: Matchock Robert L.
Published: March 2008

The prenatal environment of the human fetus is now known to have lasting physiological and behavioral effects into childhood and adulthood. The objective of this study was to examine the relationship between early testosterone exposure, as measured by the ratio of the length of the 2nd and 4th digits (2D:4D ratio), and age of menarche. Retrospective, self‐report data on menarcheal age were obtained from 206 healthy female college students, as well as finger length ratio data from both hands. Low right‐hand 2D:4D ratios (but not left‐hand) were associated with delayed menarche. The results provide evidence for an androgen‐delayed menarche link and suggest that this relationship can be continuous in nature and not always categorical as occurs in congenital adrenal hyperplasia, hyperandrogenism, or polycystic ovary syndrome. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Expanded clinical phenotype of women with the FMR1 premutation
Authors: Coffey Sarah M. , Cook Kylee , Tartaglia Nicole , Tassone Flora , Nguyen Danh V. , Pan Ruiqin , Bronsky Hannah E. , Yuhas Jennifer , Borodyanskaya Mariya , Grigsby Jim , Doerflinger Melanie , Hagerman Paul J. , Hagerman Randi J.
Published: March 2008

Fragile X‐associated tremor/ataxia syndrome (FXTAS) is generally considered to be uncommon in older female carriers of premutation alleles (55–200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene; however, neither prevalence, nor the nature of the clinical phenotype, has been well characterized in female carriers. In this study, we evaluated 146 female carriers (mean, 42.3 years; range, 20–75 years) with and without core features of FXTAS (tremor; gait ataxia), and 69 age‐matched controls (mean, 45.8 years; range, 21–78 years). Compared with controls, carriers with definite or probable FXTAS had greater medical co‐morbidity, with increased prevalence of thyroid disease (P = 0.0096), hypertension (P = 0.0020), seizures (P = 0.0077), peripheral neuropathy (P = 0.0040), and fibromyalgia (P = 0.0097), in addition to the typical symptoms of FXTAS–tremor (P < 0.0001) and ataxia (P < 0.0001). The non‐FXTAS premutation group had more complaints of chronic muscle pain (P = 0.0097), persistent paraesthesias in extremities (P < 0.0001), and history of tremor (P < 0.0123) than controls. The spectrum of clinical involvement in female carriers with FXTAS is quite broad, encompassing a number of medical co‐morbidities as well as the core movement disorder. The remarkable degree of thyroid dysfunction (17% in the non‐FXTAS group and 50% in the FXTAS group) warrants consideration of thyroid function studies in all female premutation carriers, particularly those with core features of FXTAS. © 2008 Wiley‐Liss, Inc.
Unique disease heritage of the Dutch‐German Mennonite population
Authors: Orton Noelle C. , Innes A. Micheil , Chudley Albert E. , Bech‐Hansen N. Torben
Published: March 2008

The Dutch‐German Mennonites are a religious isolate with foundational roots in the 16th century. A tradition of endogamy, large families, detailed genealogical records, and a unique disease history all contribute to making this a valuable population for genetic studies. Such studies in the Dutch‐German Mennonite population have already contributed to the identification of the causative genes in several conditions such as the incomplete form of X‐linked congenital stationary night blindness (CSNB2; previously iCSNB) and hypophosphatasia (HOPS), as well as the discovery of founder mutations within established disease genes (MYBPC1, CYP17α). The Dutch‐German Mennonite population provides a strong resource for gene discovery and could lead to the identification of additional disease genes with relevance to the general population. In addition, further research developments should enhance delivery of clinical genetic services to this unique community. In the current review we discuss 31 genetic conditions, including 17 with identified gene mutations, within the Dutch‐German Mennonite population. © 2008 Wiley‐Liss, Inc.
Clinical and molecular analysis of arylsulfatase E in patients with brachytelephalangic chondrodysplasia punctata
Authors: Nino Michelle , Matos‐Miranda Claudia , Maeda Momoe , Chen Li , Allanson Judith , Armour Christine , Greene Carol , Kamaluddeen Majeeda , Rita Debra , Medne Livija , Zackai Elaine , Mansour Sahar , Superti‐Furga Andrea , Lewanda Amy , Bober Michael , Rosenbaum Kenneth , Braverman Nancy
Published: March 2008

X‐linked Recessive Chondrodysplasia Punctata (CDPX1) is due to a defect in arylsulfatase E (ARSE), located on Xp22.3. Neither the substrate nor function of the encoded warfarin‐sensitive arylsulfatase has been identified and molecular analysis remains the only confirmatory diagnostic test. Nevertheless, the majority of patients evaluated have not had identifiable mutations in ARSE, and thus far 23 patients have been reported. The major clinical features in these patients are also present in a group now recognized as phenocopies, due to vitamin K deficiency in early gestation or maternal autoimmune disease. We evaluated the ARSE gene in 11 patients who met clinical criteria for CDPX1. We amplified all exons and intronic flanking sequence from each patient, and investigated suspected deletions or rearrangements by southern analysis. We identified mutations in seven individuals. Of the remainder, three had maternal conditions that further expand the phenocopy group. Thus, this group might represent a proportion of the mutation‐negative patients in previous studies. We extracted clinical information from all prior reports over the past decade and show that there are few distinguishing features on examination between these two groups of patients. This study supports heterogeneity for CDPX1‐like phenotypes and sorting these out will help to define the biological pathway and genetic contributors. © 2008 Wiley‐Liss, Inc.
Duplication of chromosome band 12q24.11q24.23 results in apparent Noonan syndrome
Authors: Shchelochkov Oleg A. , Patel Ankita , Weissenberger George M. , Chinault A. Craig , Wiszniewska Joanna , Fernandes Priscilla H. , Eng Christine , Kukolich Mary K. , Sutton V. Reid
Published: March 2008

Noonan syndrome is an autosomal dominant disorder with an estimated incidence of 1 in 1,000 to 1 in 2,500 live births. It is characterized by postnatal‐onset short stature, characteristic facial changes, webbed neck, pectus carinatum, or excavatum, congenital heart defects, and bleeding abnormalities. Gain‐of‐function mutations in the PTPN11, KRAS, SOS1, and RAF1 genes that are components of the RAS/MEPK signaling pathway are identified in about 70–85% of individuals with Noonan syndrome. We report here a case of duplication of chromosome region 12q24.11q24.23 identified by array comparative genomic hybridization (aCGH) that includes the PTPN11 gene in a 3‐year‐old girl with apparent Noonan syndrome. The patient presented with postnatal‐onset failure‐to‐thrive, developmental delay, microcephaly, velopalatal incompetence, pectus excavatum, coarctation of aorta, atrial and ventricular septal defects, decreased muscle tone, and minor facial anomalies consistent with Noonan syndrome. At 3 years of age her speech, gross and fine motor development were at the level of a 12–18 month old child. This degree of developmental delay was atypical for an individual with Noonan syndrome, raising concerns for a chromosomal abnormality. Array‐CGH showed an interstitial duplication of 10 Mb including the PTPN11 gene. Sequencing of PTPN11, KRAS, SOS1 and the coding region of RAF1 did not identify mutations. The increased gene dosage of the PTPN11 gene in the form of duplication is expected to have the same consequence as gain‐of‐function mutations seen in Noonan syndrome. We propose that at least some of the 15–30% of individuals with Noonan syndrome who do not have a mutation by sequencing may have a gain in copy number of PTPN11 and recommend that comprehensive testing for Noonan syndrome should include analysis for copy number changes of PTPN11. © 2008 Wiley‐Liss, Inc.
Highly variable cutis laxa resulting from a dominant splicing mutation of the elastin gene
Authors: Graul‐Neumann Luitgard M. , Hausser Ingrid , Essayie Maximilian , Rauch Anita , Kraus Cornelia
Published: March 2008

Autosomal dominant congenital cutis laxa (ADCL) is genetically heterogeneous and shows clinical variability. Only seven ADCL families with mutations in the elastin gene (ELN) have been described previously. We present morphological and molecular genetic studies in a cutis laxa kindred with a previously undescribed highly variable phenotype caused by a novel ELN mutation c.1621 C > T. The proband presented with severe cutis laxa, severe congenital lung disease previously undescribed in ADCL and pulmonary artery disease, which is often seen in ARCL but rare in ADCL. He also developed infantile spasms (OMIM 308350; West syndrome), which we consider a coincidental association although recessive cutis laxa or even digenic inheritance cannot be excluded. Electron microscopy of the proband's dermis revealed only mild rarefication of elastic fibers (in contrast to most recessive cutis laxa types). Apart from mild elastic fiber fragmentation, dermal morphology of the proband's father was within normal range. Molecular analysis of the ELN gene using genomic DNA from blood and RNA from cultured skin fibroblasts indicated a novel splice site mutation in the proband and his clinically healthy father. Analysis of ELN expression in fibroblasts provided evidence for a dominant‐negative effect in the child, while due to an unknown mechanism, the father showed haploinsufficiency which might explain the significant clinical variability. © 2008 Wiley‐Liss, Inc.
Association of homozygous LMNA mutation R471C with new phenotype: Mandibuloacral dysplasia, progeria, and rigid spine muscular dystrophy
Authors: Zirn Birgit , Kress Wolfram , Grimm Tiemo , Berthold Lars Daniel , Neubauer Bernd , Kuchelmeister Klaus , Müller Ulrich , Hahn Andreas
Published: March 2008

We report on a 7‐year‐old girl with a phenotype combining mandibuloacral dysplasia (MAD), progeria, and rigid spine muscular dystrophy. Mild proximal weakness, contractures, and rigidity of the spine were the primary findings. Although present since birth, dysmorphic manifestations typical for MAD and progeroid features became more prominent with time, and the full clinical phenotype was recognizable at early school age. Her phenotype was caused by a homozygous mutation in LMNA (c.1411C > T, which predicts p.R471C) inherited from the heterozygous, consanguineous, unaffected parents. This mutation has only been reported in compound heterozygous state and was associated with a milder phenotype. Some LMNA mutations are known to cause MAD and overlapping phenotypes (MAD spectrum) in an autosomal recessive pattern. The p.R471C homozygous LMNA mutation causes a severe phenotype of the MAD spectrum. This case extends the clinical spectrum of MAD and further expands the phenotypic range of lamin A/C associated diseases. © 2008 Wiley‐Liss, Inc.
Ideal surface geometries of nucleating agents to enhance cell nucleation in polymeric foaming processes
Authors: Leung Siu N. , Wong Anson , Park Chul B. , Zong Jin Ho
Published: March 2008

Ideal nucleating agents are expected to improve the cell morphology of plastics foams (i.e., increasing the cell density, reducing the cell size, and narrowing cell‐size distribution) by providing heterogeneous nucleation sites. A nucleating agent's surface geometry is one factor that governs its nucleating power. This paper discusses the surface geometry of an ideal nucleating agent. On the basis of computer simulations of a batch foaming process using polystyrene and carbon dioxide, we found that nucleating agents having numerous crevices with small semiconical angles are the most desirable for polymeric foaming processes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Preparation of polysulfonebenzylthiourea‐reactive ultrafiltration plate membranes and their rejection properties for heavy toxic metal cations
Authors: Wang Bing , Huangfu Fengyun , Liu Wei
Published: March 2008

The asymmetric membranes were prepared via phase inversion method, by using chloromethyl polysulfone as membrane materials, polyethylene glycol (PEG) as pore forming agent to improve the morphology and function of resultant membranes, N,N‐dimethylacetamide as solvent, and water as the extraction solvent. Then the highly qualified polysulfonebenzylthiourea‐reactive ultrafiltration plate membrane was prepared successively through the reactions between the chloromethyl polysulfone matrix membrane and thiourea. The thiourea‐functionalized polysulfone plate reactive ultrafiltration membrane was used for the rejection of heavy toxic metal cations such as Cd2+ and Zn2+ through the coordination of the thiourea group and heavy toxic metal cations, in which the effects of the morphological and the structure of the membrane on the rejection properties were investigated. The rejection conditions, including the concentration of heavy toxic metal cations, temperature and pH of the solution had significant effects on the rejection capacity of polysulfonebenzylthiourea‐reactive ultrafiltration membrane. The reactive ultrafiltration membrane containing thiourea group can be conveniently recovered by dilute hydrochloric acid for coordination of heavy toxic metal cations, which would have wide application for the treatment of waste‐water‐containing heavy toxic metal cations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Synthesis of Fluorinated Dienes by Palladium‐Catalyzed Coupling Reactions
Authors: Akkerman Floris A. , Kickbusch Rainer , Lentz Dieter
Published: March 2008

The synthesis of partly fluorinated 1,3‐ and 1,4‐dienes by palladium‐catalyzed coupling makes these compounds available on the laboratory scale. Several catalyst systems were tested to maximize the yields and minimize the by‐products. The molecular structures of 1,1,2,4,4‐pentafluorobutadiene, chloro(N,N′‐tetramethylethylenediamine)(trifluorovinyl)zinc, PCy2R, and P(O)Cy2R (Cy=cyclohexyl, R=2‐(1‐naphthyl)phenyl) were elucidated by X‐ray crystallography.
Latest Developments in the Catalytic Application of Nanoscaled Neutral Group 8–10 Metals
Authors: Zhu Yinghuai , Lee Cjin Nong , Kemp Richard A. , Hosmane Narayan S. , Maguire John A.
Published: March 2008

In the last few decades, the synthesis and catalytic application of nanoscaled particles prepared from Group 8–10 (formerly Group VIIIB) elements have been widely explored and have achieved promising results. The innovative use of these nanoparticle catalysts may provide new opportunities in the efficient combination of conventionally used homogenous and heterogeneous catalysts. Conventional homogeneous catalysts pose extraction and recycling difficulties when dealing with metal complexes and/or ligands, whereas heterogeneous catalysts generally require more pressing experimental conditions, such as high temperatures and high pressures, to be effective. Therefore, to solve these problems, the synthesis and use of nanoparticle catalysts as replacements for conventional catalytic systems is a breakthrough owing to their improved handling and environmental and economic aspects. This Focus Review primarily addresses the catalytic applications of neutral Group 8–10 nanoparticles with an average size of less than 10 nm, and also includes a discussion of commonly used synthetic methodology.