bluuebunny/crossref_metadata_2025_split huggingface dataset:
The visual pigments of a deep-sea teleost, the pearl eyeScopelarchus analis
Authors: Pointer Marie A. , Carvalho Livia S. , Cowing Jill A. , Bowmaker James K. , Hunt David M. 
Published: August 2007

SUMMARYThe eyes of deep-sea fish have evolved to function under vastly reduced light conditions compared to those that inhabit surface waters. This has led to a bathochromatic shift in the spectral location of maximum absorbance(λmax) of their rod (RH1) pigments and the loss of cone photoreceptors. There are exceptions to this, however, as demonstrated by the deep-sea pearl eye Scopelarchus analis. Here we show the presence of two RH1 pigments (termed RH1A and RH1B) and a cone RH2 pigment. This is therefore the first time that the presence of a cone pigment in a deep-sea fish has been confirmed by molecular analysis. The λmaxvalues of the RH1A and RH1B pigments at 486 and 479 nm, respectively, have been determined by in vitro expression of the recombinant opsins and show the typical short-wave shifts of fish that live in deep water compared to surface dwellers. RH1B, however, is expressed only in more adult fish and lacks key residues for phosphorylation, indicating that it may not be involved in image formation. In contrast, the RH2 pigment has additional residues near the C terminus that may be involved in phosphorylation and does not show temporal changes in expression. The distribution of these pigments within the multiple retinae of S. analis is discussed.
Sensory-induced modification of two motor patterns in the crab,Cancer pagurus
Authors: Smarandache Carmen R. , Stein Wolfgang 
Published: August 2007

SUMMARYSensory input is pervasive among motor networks and continuously adapts motor patterns to changing circumstances. To elucidate common principles of sensorimotor integration, it is beneficial to characterize sensory influences on motor network operation and compare these influences between species. To facilitate such comparison, we have studied the influence of the anterior gastric receptor (AGR) – a proprioceptor that has been characterized in detail in two lobster species – on the pyloric (filtering of food) and gastric mill (chewing of food) motor patterns in the crab Cancer pagurus.AGR has a bipolar cell body in the stomatogastric ganglion; it was activated by tension increase in gastric mill powerstroke muscles. While two spike initiation zones accounted for its spontaneous activity, active membrane properties (sag potentials, spike frequency adaptation) contributed to the AGR response to current injections.When activated, AGR diminished spike activities in two pyloric motor neurons and prolonged the pyloric cycle period. Furthermore, AGR excited gastric mill protractor neurons, inhibited the retractor neuron and evoked phase-independent resetting of the gastric mill rhythm. Repetitive spike trains entrained the rhythm to both longer and shorter cycle periods. All AGR actions seemed to be mediated via at least two premotor projection neurons in the spatially distant commissural ganglia. The response of the gastric mill neurons was independent of AGR firing frequency.Our results suggest that homologous proprioceptors can elicit similar effects on motor patterns while utilizing different mechanisms. This work thus provides an initial framework for future studies to determine underlying common principles.
The imaging properties and sensitivity of the facial pits of pitvipers as determined by optical and heat-transfer analysis
Authors: Bakken George S. , Krochmal Aaron R. 
Published: August 2007

SUMMARYIt is commonly assumed that the facial pit of pitvipers forms relatively sharp images and can detect small differences in environmental surface temperatures. We have visualized the temperature contrast images formed on the facial pit membrane using a detailed optical and heat transfer analysis, which includes heat transfer through the air in the pit chambers as well as via thermal infrared radiation. We find the image on the membrane to be poorly focused and of very low temperature contrast. Heat flow through the air in the pit chambers severely limits sensitivity, particularly for small animals with small facial pit chambers. The aperture of the facial pit appears to be larger than is optimal for detecting small targets such as prey at 0.5 m. Angular resolution (i.e. sharpness) and image strength and contrast vary complexly with the size of the pit opening. As a result, the patterns of natural background temperatures obscure prey items and other environmental features, creating false patterns. Consequently, snakes cannot simply target the strongest signal to strike prey. To account for observed behavioral capabilities, the sensory endings on the pit membrane apparently must respond to temperature contrasts of 0.001°C or less. While neural image sharpening likely enhances imaging performance, it appears important for foraging snakes to select ambush sites offering uniform backgrounds and strong thermal contrasts. As the ancestral facial pit was likely less sensitive than the current organ, objects with strong thermal signals, such as habitat features,were needed to drive the evolution of this remarkable sense.
Beneficial acclimation: sex specific thermal acclimation of metabolic capacity in the striped marsh frog (Limnodynastes peronii)
Authors: Rogers Kris D. , Thompson Michael B. , Seebacher Frank 
Published: August 2007

SUMMARYReproductive success in thermally varying environments will depend on maintaining metabolic capacity of tissues that are important in mating behaviours. Here we test the hypothesis that cold acclimation will occur in those tissues that are important for reproduction, and that acclimation will be sex specific, reflecting behavioural differences between the sexes. We used the frog Limnodynastes peronii as a model because anurans engage in energetically demanding reproductive behaviour, and many species, including L. peronii, are reproductively active across seasons. Additionally,reproductive behaviours such as calling and amplexus are sex specific. We acclimated animals to naturally occurring autumn (15°C, N=10) and summer (25°C, N=10) temperatures. Whole-animal resting oxygen consumption decreased with lowered temperature, but there was no difference in oxygen consumption between acclimation treatments or sexes. However, the respiratory control ratio (RCR) of mitochondria from the liver and external oblique calling muscle increased with cold acclimation. The increase in RCR with thermal acclimation was due to upregulation of state 3 respiration, and not to a decrease in state 4 respiration. Males had higher activity of citrate synthase, β-hydroxyacyl CoA dehydrogenase and cytochrome coxidase than females in the calling (external oblique) muscle, and males also showed thermal acclimation of these enzymes while females did not. Additionally, males had greater activity of metabolic enzymes in the principal muscle (extensor carpi radialis) used during amplexus. However, there were no differences in metabolic capacity between sexes in the gastrocnemius muscle and in liver, and both sexes showed significant acclimation of lactate dehydrogenase and cytochrome c oxidase in the former and latter,respectively. In L. peronii, thermal acclimation of metabolic capacities is linked to reproductive success, and reversible phenotypic plasticity therefore confers a selective advantage by extending the temporal and spatial extent of the animals' fundamental niche.
Strength Correlation of High Performance Concrete Using Different Sized Specimens
Authors: Issa Mohsen A. , Saccomonto Mark J. 
Published: August 2007

Abstract
The length to diameter ratio (L/d) of cylindrical concrete specimens is the main factor that affects the compressive strength of concrete. A total of more than 200 molded and cored high performance concrete cylinders of 100- and 150-mm diameters with various L/d ratios were tested to failure at 28 and 105 days. The results confirmed that the concrete strength varies significantly not only with the L/d ratio, but also with the curing method, core location, and specimen size. The current ASTM Standards C 39 and C 42 correction factors underestimate the strength test results in some cases and overestimate the results in other cases, which dictate the need for revising the ASTM correction factors for the high performance concrete. Based on a nonlinear regression analysis of the test results, strength correction factors for each specimen type were presented in figures and tables along with the correction factors provided by the ASTM standards.
Practice, Education and Research for Sustainable Infrastructure (PERSI)
Authors: Wright Richard N. 
Published: August 2007

Abstract
Practice, Education and Research for Sustainable Infrastructure (PERSI) is an initiative of the U.S. infrastructure community. PERSI seeks to advance and incorporate concepts and knowledge of sustainability into the standards and practices used throughout the life cycle of infrastructure systems. PERSI will not itself produce standards and practices, but will help ASTM and its other member organizations address sustainability consistently in their practices and standards. PERSI’s immediate objectives are to assess current practices and standards and develop agendas for: 1. Implementation of best available practices; 2. Development of improved practices to exploit available knowledge; 3. Research to fill important gaps in knowledge; 4. Education of current and future infrastructure professionals and technicians. Proposed techniques for assessment of practices use whole life-cycle approaches to address environmental, economic, and social aspects of sustainability. These approaches have been widely used and standardized for assessments of environmental and economic sustainability of building materials and components. The scope of the assessment is broad in order to identify the most significant opportunities to improve the sustainability of infrastructure. The scopes of the agendas will be focused on these most significant opportunities.
General Photo‐Patterning of Polyelectrolyte Thin Films via Efficient Ionic Bis(Fluorinated Phenyl Azide) Photo‐Crosslinkers and their Post‐Deposition Modification
Authors: Khong S.‐H. , Sivaramakrishnan S. , Png R.‐Q. , Wong L.‐Y. , Chia P.‐J. , Chua L.‐L. , Ho P. K. H. 
Published: August 2007

AbstractWe have extended the well known bisfluorinated(phenyl azide) (bisFPA) methodology to develop an ionic bisFPA process suitable for photo‐crosslinking a wide variety of polyelectrolyte thin films. The crosslinking efficiencies (0.1–1.0 crosslink per photo‐reaction) are sufficiently high for the gel fraction to exceed 80 % for crosslinker concentrations of only a few weight %. This method is based on the photo‐induced formation of singlet nitrenes from FPAs and their insertion into unactivated C–H or other bonds, which thus general and not dependent on the presence of specific chemical functional groups. By derivatizing with ionic charge groups, we obtained ionic bisFPAs that can be properly dispersed into polyelectrolyte thin films. The sorbed moisture always present in these films however severely limits the photo‐crosslinking efficiency, apparently through nitrene protonation and intersystem crossing. This can be avoided by dehydration of the films, in some cases, to 130 °C for 10 min in nitrogen before photo‐exposure. We found that efficient photo‐crosslinking can then be achieved for polyelectrolytes even when they have nucleophilic groups. These include poly(styrenesulfonic acid) and their salts, poly(acrylic acid) and their salts, poly(dimethyldiallylammonium salts), as well as the electrically‐conducting poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonic acid) complex (PEDT:PSSH). We further demonstrate using this ionic bisFPA methodology both photo‐patterning and post‐deposition chemical modifications of polyelectrolyte thin films. This opens broad new possibilities in membrane, sensor and actuator technologies, as well as for organic semiconductor plastic electronics (such as field‐effect transistors) and polyelectrolyte‐based devices.
Interfacial Effect on Dielectric Properties of Polymer Nanocomposites Filled with Core/Shell‐Structured Particles
Authors: Shen Y. , Lin Y. H. , Nan C.‐W. 
Published: August 2007

AbstractNovel polymer nanocomposites were prepared by solution processing with core/shell structured nanoparticles (carbonaceous shell coating on silver cores) as fillers. The organic carbonaceous shells act as interlayers between the Ag cores as well as with the polymer matrix. It is shown that the electrical properties of the interlayers play a dominative role in determining the dielectric behavior of the nanocomposites. Insulating interlayers reduce the tunnel current between neighboring Ag cores by causing potential barriers, endowing the nanocomposites with stable and high dielectric constants and low dielectric loss. Furthermore, the stable dielectric constants of the nanocomposites could be tuned by adjusting the thickness of the interlayers. Increasing the conductivity of the interlayers lowers the potential barriers, making the dielectric behavior of the nanocomposites more similar to that of conventional percolative composites.
Growth among Tibetans at high and low altitudes in India
Authors: Tripathy Vikal , Gupta Ranjan 
Published: August 2007

AbstractIn India, Tibetans have been living at different altitudes for more than 40 years. This study describes physical growth in terms of height, weight, sitting height, skinfold thickness at triceps and upper arm circumference of Tibetans born and raised at three Tibetan refugee settlements (3,521; 970; and 800 m) from the view point of the hypothesis that growth is retarded at high altitude. Samples consist of individuals between the ages of 2 and 40 years. Tibetans at high altitude in India show a growth pattern similar to that previously observed among Tibetans in Tibet. Tibetans at high altitude are taller and heavier compared to Andean highlanders. The general trends show that Tibetan children and adults of both sexes at low altitude in India are advanced in terms of height, weight, skinfold thickness at triceps and upper arm circumference compared to Tibetans at high altitude. Trunk length (sitting height) is similar at the two altitudes but relative sitting height is greater at high altitude. Greater relative sitting height and lesser leg length at high altitude than at low altitudes is discussed in terms of effect of altitude, temperature, and nutritional status. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
Improving dispersion of multiwalled carbon nanotubes in polyamide 6 composites through amino‐functionalization
Authors: Li Juan , Fang Zhengping , Tong Lifang , Gu Aijuan , Liu Fu 
Published: August 2007

AbstractThe focus of this study is to investigate the state of dispersion of different treated multiwalled carbon nanotubes (MWNTs) in polyamide 6 (PA6). The MWNTs used in composites were grafted by 1,6‐hexamethylenediamine (HMD) via acid‐thionyl chloride to improve their compatibility with PA6 matrix. A microstructure transformation of MWNTs is found during the treatment process. Acidification makes the MWNTs compact and grafting HMD promotes the compact structure loose again. The MWNTs after different treatment were used to fabricate MWNTs/PA6 composites through melt blending. The dispersion of different MWNTs in PA6 was observed by a combination of scanning electron microscopy, optical microscopy, and transmission electron microscopy. The results show that the amino‐functionalized MWNTs are dispersed more homogeneously in PA6 than the purified MWNTs, and the poorest dispersion is achieved for acid treated MWNTs. It is indicated that the loose structure and functionalized surface of MWNTs benefit the dispersion of MWNTs in PA6. In addition, the amino‐functionalization of MWNTs improves the compatibility between the MWNTs and PA6, resulting in stronger interfacial adhesion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and characterization of biodegradable network poly(ethylene glycol) films with elastic properties
Authors: Nagata Minoru , Sugiura Ryosuke , Sakai Wataru , Tsutsumi Naoto 
Published: August 2007

AbstractNovel biodegradable network films with elastic properties were prepared from trimesic acid (Y) and poly(ethylene glycol)s (PEGs) with different molecular weights (MW) and/or 4,7,10‐trioxa‐1,13‐tridecanediamine (I). Prepolymers prepared by a melt polycondensation were cast from N,N′‐dimethylformamide solution and postpolymerized at 290°C for various times to form a network. The resultant films were transparent, flexible, and insoluble in organic solvents. The X‐ray diffraction scattering pattern showed that all network films are amorphous. The densities of the network films decreased, whereas their water uptake increased with increasing MWs of PEG. The thermal and tensile properties were measured in dry and wet conditions and were affected remarkably not only by MWs of PEG, but also by the water uptake of the films. The glass transition temperatures (Tg) decreased with increasing MWs of PEG. YPEG200 and YPEG1000 films showed good elastomeric properties with an ultimate elongation of 225 and 277%, respectively, in dry condition. The tensile strength of 13 MPa and Young's modulus of 214 MPa were the highest for YPEG200 among the network elastic films studied. All sample films in wet condition had lower Tg's and tensile properties. The hydrolytic degradation was measured by the weight loss of network films in a buffer solution with or without Rhizopus delemar lipase at 37°C. The degree and the rate of the degradation increased with increasing MWs of PEG, which is compatible with the increase in water uptake of the films. Incorporation of large amount of I moiety into YPEG1000 film increased the glass transition temperatures, tensile strength and Young's modulus, but depressed elastic nature of the films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Flame retardant polyesters. I. Phosphorous flame retardants
Authors: Yang Seung‐Cheol , Kim Jae Pil 
Published: August 2007

AbstractCommercially available two types of phosphorous flame retardants (FRs) for polyester were compared from the viewpoint of chemical reactivity, reaction mechanism, and byproduct formation. 3‐(Hydroxyphenyl phosphinyl) propanoic acid (HPP) and 9,10‐dihydro‐9‐oxa‐10‐2,3‐dicarbonylpropyl)‐10‐phosphophenanthrene‐10‐oxide (DI) were used as a main chain type and a pendant type, respectively. HPP and DI showed different behavior with ethylene glycol (EG). More acidic HPP reacted with EG spontaneously and then produced esterified terminal hydroxy end group reacted with EG to form terminal diethylene glycol (DEG) end group. But the composition in the HPP solution was not varied for a long time below the esterification temperature. Contrast to HPP, DI showed normal esterification procedure. DI esterified with EG to form DI ester of EG, and DEG formation is not distinct. The difference of reactivity and DEG formation is caused by the difference of acidity in EG solution. For production of phosphorous containing polyester, it is desirable that HPP is introduced into the reactor in the mere solution state and DI in the esterified state. In addition, for production of polyester having the same phosphorous content in commercial scale, it is more beneficial to apply HPP than DI because of low input of FR due to low molecular weight. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and characterization of the chiral stationary phase based on chitosan
Authors: Son Seung‐Hee , Jegal Jonggeon 
Published: August 2007

AbstractChitosan was modified with N‐nicotinoyl‐L‐phenylalanine and 3,5‐dimethylphenylisocyanate to prepare a chiral stationary phase for the high performance liquid chromatography application, especially for the separation of optical isomers of series of α‐amino acids. The modified chitosan with N‐nicotinoyl‐L‐phenylalanine group and 3,5‐dimethylphenylcarbamate group was characterized with several analytical methods such as differential scanning calorimeter, thermo gravimetric analyzer, X‐ray diffractometer, and HPLC; its solubility, thermal property, and chiral separation performance were studied. Contrary to chitosan, the modified chitosan prepared in this study showed good solubility in several organic solvents and was easy to handle to coat the silica particles to prepare chiral HPLC column. It showed good chiral separation capabilities. It was also thermally stable at over 100°C, suggesting potential wide operating temperature range of its chiral HPLC column. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Thermodynamics of Hydrophobic Interactions: Entropic Recognition of a Hydrophobic Moiety by Poly(Ethylene Oxide)–Zinc Porphyrin Conjugates
Authors: Iwamoto Hiroya , Mizutani Tadashi , Kano Koji 
Published: August 2007

AbstractThe recognition of 4‐alkylpyridines by water‐soluble poly(ethylene oxide)–zinc porphyrin conjugates was studied with a focus on the thermodynamic parameters of binding. Microcalorimetric studies indicated that binding of the alkyl group of the guest in water is driven by the entropic term (δΔH0=ΔH0(4‐pentylpyridine)− ΔH0(4‐methylpyridine)=+1.7 kJ mol−1, δTΔS0=TΔS0(4‐pentylpyridine)− TΔS0(4‐methylpyridine)=+11.8 kJ mol−1 at 298 K), thus showing the significance of water reorganization during host–guest interaction. The enthalpy–entropy compensation temperature of binding of 4‐alkylpyridines was as low as 38 K; only below this temperature could the enthalpic term be a driving force. The binding affinity was modulated by the addition of cations and by varying the degree of polymerization of poly(ethylene oxide), which suggests that guest binding is coupled with polymer conformation.
CD38 regulates oxytocin secretion and complex social behavior
Authors: Bartz Jennifer A. , McInnes L. Alison 
Published: August 2007

AbstractThe peptide hormone oxytocin plays a critical role in regulating affiliative behaviors including mating, pair‐bond formation, maternal/parenting behavior, social recognition, separation distress and other aspects of attachment. Jin and colleagues1 recently reported intriguing findings that CD38, a transmembrane receptor with ADP‐ribosyl cyclase activity, plays a critical role in maternal nurturing behavior and social recognition by regulating oxytocin secretion. This research may have implications for understanding disorders marked by deficits in social cognition and social functioning, including autism, social anxiety disorder, borderline personality disorder and schizophrenia. BioEssays 29:837–841, 2007. © 2007 Wiley Periodicals, Inc.