bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrative biology of an embryonic respiratory behaviour in pond snails:the `embryo stir-bar hypothesis'
Authors: Goldberg Jeffrey I. , Doran Shandra A. , Shartau Ryan B. , Pon Julia R. , Ali Declan W. , Tam Rose , Kuang Shihuan 
Published: May 2008

SUMMARYEmbryos of freshwater snails undergo direct development from single cell to juvenile inside egg masses that are deposited on vegetation and other substratum in pond, lake and stream habitats. Helisoma trivolvis, a member of the Planorbidae family of basommatophoran snails, has served as a model for studying the developmental and physiological roles for neurotransmitters during embryogenesis. Early studies revealed that H. trivolvis embryos from stage E15 to E30, the period between gastrulation and the trochophore–juvenile transition, display a cilia-driven behaviour consisting of slow basal rotation and transient periods of rapid rotation. The discovery of a bilateral pair of early serotonergic neurons,named ENC1, which project an apical process to the embryo surface and basal neurites to ciliated cells, prompted the hypothesis that each ENC1 is a dual-function sensory and motor neuron mediating a physiological embryonic response. This article reviews our past and present studies and addresses questions concerning this hypothesis, including the following. (1) What environmental signal regulates ENC1 activity and rotational behaviour? (2)Does ENC1 function as both a primary sensory and motor neuron underlying the rotational behaviour? (3) What are the sensory transduction mechanisms? (4)How does ENC1 regulate ciliary beating? (5) Do other basommatophoran species have similar neural–ciliary pathways and behavioural responses? (6) How is the behaviour manifest in the dynamic natural environment? In this review,we introduce the `embryo stir-bar hypothesis', which proposes that embryonic rotation is a hypoxia-sensitive respiratory behaviour responsible for mixing the egg capsule fluid, thereby enhancing delivery of environmental oxygen to the embryo.
Computational mechanisms of mechanosensory processing in the cricket
Authors: Jacobs Gwen A. , Miller John P. , Aldworth Zane 
Published: May 2008

SUMMARY
Crickets and many other orthopteran insects face the challenge of gathering sensory information from the environment from a set of multi-modal sensory organs and transforming these stimuli into patterns of neural activity that can encode behaviorally relevant stimuli. The cercal mechanosensory system transduces low frequency air movements near the animal's body and is involved in many behaviors including escape from predators, orientation with respect to gravity, flight steering, aggression and mating behaviors. Three populations of neurons are sensitive to both the direction and dynamics of air currents:an array of mechanoreceptor-coupled sensory neurons, identified local interneurons and identified projection interneurons. The sensory neurons form a functional map of air current direction within the central nervous system that represents the direction of air currents as three-dimensional spatio-temporal activity patterns. These dynamic activity patterns provide excitatory input to interneurons whose sensitivity and spiking output depend on the location of the neuronal arbors within the sensory map and the biophysical and electronic properties of the cell structure. Sets of bilaterally symmetric interneurons can encode the direction of an air current stimulus by their ensemble activity patterns, functioning much like a Cartesian coordinate system. These interneurons are capable of responding to specific dynamic stimuli with precise temporal patterns of action potentials that may encode these stimuli using temporal encoding schemes. Thus, a relatively simple mechanosensory system employs a variety of complex computational mechanisms to provide the animal with relevant information about its environment.
Ion channels in mammalian vestibular afferents may set regularity of firing
Authors: Eatock Ruth Anne , Xue Jingbing , Kalluri Radha 
Published: May 2008

SUMMARY
Rodent vestibular afferent neurons offer several advantages as a model system for investigating the significance and origins of regularity in neuronal firing interval. Their regularity has a bimodal distribution that defines regular and irregular afferent classes. Factors likely to be involved in setting firing regularity include the morphology and physiology of the afferents' contacts with hair cells, which may influence the averaging of synaptic noise and the afferents' intrinsic electrical properties. In vitro patch clamp studies on the cell bodies of primary vestibular afferents reveal a rich diversity of ion channels, with indications of at least two neuronal populations. Here we suggest that firing patterns of isolated vestibular ganglion somata reflect intrinsic ion channel properties,which in vivo combine with hair cell synaptic drive to produce regular and irregular firing.
Linear and nonlinear processing in hair cells
Authors: Roberts William M. , Rutherford Mark A. 
Published: May 2008

SUMMARY
Mechanosensory hair cells in the ear are exquisitely responsive to minute sensory inputs, nearly to the point of instability. Active mechanisms bias the transduction apparatus and subsequent electrical amplification away from saturation in either the negative or positive direction, to an operating point where the response to small signals is approximately linear. An active force generator coupled directly to the transducer enhances sensitivity and frequency selectivity, and counteracts energy loss to viscous drag. Active electrical amplification further enhances gain and frequency selectivity. In both cases, nonlinear properties may maintain the system close to instability,as evidenced by small spontaneous oscillations, while providing a compressive nonlinearity that increases the cell's operating range. Transmitter release also appears to be frequency selective and biased to operate most effectively near the resting potential. This brief overview will consider the resting stability of hair cells, and their responses to small perturbations that correspond to soft sounds or small accelerations.
Percolation-type Photoswitching Behavior in Conductance of Diarylethene–Silver Nanoparticle Networks
Authors: Sakano Takeshi , Yamaguchi Hidehiro , Tanifuji Naoki , Irie Masahiro , Matsuda Kenji 
Published: May 2008

Abstract
A silver nanoparticle network interlinked by photochromic diarylethene dithiophenols was fabricated and its photoreactive and conductive properties were investigated. The network showed reversible changes in absorption spectra and conductance by photoirradiation. The results indicate the percolation-type behavior.
Liquid-phase Electrodeposition of Diamond-like Carbon Films on Conducting Glass Substrates Using a Low Deposition Voltage at Room Temperature
Authors: Wang Yi , Yang Wensheng , Chen Chen 
Published: May 2008

Abstract
By using formamide as the carbon source, an attempt was made to electrodeposit diamond-like carbon (DLC) films on indium tin oxide (ITO)-coated glass plate substrates at a low constant voltage and room temperature. The structures and morphologies of the films were analyzed by Raman spectroscopy and field-emission scanning electron microscopy.
Oxygen Absorption Capability of YBaCo4O7+δ
Authors: Räsänen Samuli , Yamauchi Hisao , Karppinen Maarit 
Published: May 2008

Abstract
Various powerful oxygenation approaches were tested in order to find the limits of the oxygen-storage capability of YBaCo4O7+δ. By means of extreme solid-medium high-pressure oxygenation employing KClO3 as an oxygen generator the phase was successfully loaded with excess oxygen up to δ≈1.56.
Modulation of Solid-state Luminescence Quantum Efficiency Based on CH–O Intermolecular Interaction
Authors: Hinoue Tomoaki , Mizobe Yuji , Hisaki Ichiro , Miyata Mikiji , Tohnai Norimitsu 
Published: May 2008

Abstract
Solid-state luminescence quantum efficiency is modulated drastically by CH–O interaction and packing rigidity of secondary ammonium anthracene-2,6-disulfonate. Appropriate alkyl chains of amines gave small free space and long CH–O distance, resulting in strong luminescence due to suppression of nonradiative decay. This is the first demonstration that CH–O intermolecular interaction has great influence on solid-state luminescence quantum efficiency.
Solvothermal Preparation of Silicon Nanocrystals
Authors: Qiu Jun , Shen Wanqing , Yu Ruijie , Yao Baodian 
Published: May 2008

Abstract
Silicon nanocrystals have been produced successfully by using silicon monoxide as the starting material via a simple solvothermal preparation method. The temperature needed in the solvothermal preparation is found to be as low as 220 °C when ethylenediamine is used as the solvent. The as-prepared silicon samples are of single-crystal nature with diameters around 5 nanometers and dispersed in an amorphous silica. The silicon nanocrystals became a little larger in size after removing the amorphous silica, according to the results of transmission electron microscope (TEM) characterization.
Copper-catalyzed Oxidative Desulfurization-promoted Intramolecular Cyclization of Thioamides Using Molecular Oxygen as an Oxidant: An Efficient Route to Five- to Seven-membered Nitrogen-containing Heterocycles
Authors: Shibahara Fumitoshi , Yoshida Atsunori , Murai Toshiaki 
Published: May 2008

Abstract
Copper-catalyzed oxidative desulfurization-promoted intramolecular cyclization reactions of thioamides take place under neutral and mild conditions by using molecular oxygen as an oxidant. The process yields a wide variety of nitrogen-containing heterocycles with high efficiency.
Injuries in Norwegian Ski Resorts the Winter Seasons of 2005 and 2006
Authors: Ekeland Arne , Rødven Andreas 
Published: May 2008

Abstract
A central ski patrol-based registration of skiing and boarding injuries was performed by the Norwegian Ski Lift Association during the winter seasons 2004/2005 and 2005/2006. Totals of 8130 injured skiers/boarders and 5.466 million skier/boarder days were recorded during the two seasons, giving an injury rate of 1.5 injured per 1000 skier/boarder days. Most of the injuries occurred during alpine skiing (58 %) and snowboarding (35 %), compared to telemark skiing (3 %) and skiboarding (4 %). Wrist injuries were common among injured snowboarders (26 %) compared to only 5 % each for the others (P&lt;0.001). The knee was the main injury location in alpine skiers (24 %) compared to 23 % among skiboarders, 14 % among telemarkers and only 7 % among snowboarders (P&lt;0.001). The percentage of knee injuries in females (28 %) was almost twice as high as for males (P&lt;0.001), whereas shoulder injuries were twice as high in males (17 %) as in females (8 %) (P&lt;0.001). As a percentage of all injuries, skiboarders suffered more fractures (34 %) than snowboarders (33 %), telemarkers (26 %), and alpine skiers (22 %) (P&lt;0.001), but fracture of the lower leg was uncommon among snowboarders (1 %) and telemarkers (3 %) compared to alpine skiers (6 %) and skiboarders (13 %) (P&lt;0.001). Lower leg fractures accounted for 4 % of the injured alpine skiers 20 years and older, 3 % for adolescents aged 13 – 19 years compared to 13 % for children 12 years and younger (P&lt;0.001). Twenty percent of the skiers/boarders were injured in terrain parks. They suffered more fractures, head, and back injuries than those injured on groomed slopes (P&lt;0.01). In conclusion, injured alpine skiers were most prone to knee injuries, and skiboarders to lower leg fractures. This fracture was still a common injury for children in these two disciplines. Injured snowboarders were most prone to suffer wrist injuries. The prevalence of knee injuries among females was almost twice that of males, whereas the reverse was observed for shoulder injuries.
Juvenile Coho Salmon Leaping Ability and Behavior in an Experimental Culvert Test Bed
Authors: Mueller Robert P. , Southard Susan S. , May Christopher W. , Pearson Walter H. , Cullinan Valerie I. 
Published: May 2008

AbstractAs part of a research program aimed at identifying the culvert configurations and associated hydraulic conditions that foster the successful upstream movement of juvenile salmon, we investigated the ability of hatchery‐raised juvenile coho salmon Oncorhynchus kisutch to leap into an experimental culvert under varying hydraulic conditions. Five outfall drops ranging from 0 to 32 cm were tested to represent differing degrees of culvert outfall drop. Trials were run at a culvert discharge of 0.028 m3/s and a tailwater pool depth of 30 cm. The median success rate was highest (85%) for the 0‐cm drop, followed by 34% at 12 cm, 20% at 20 cm, 2% at 26 cm, and 0% at 32 cm. When overcoming the 0‐cm (streaming flow) and 12‐cm drops, fish predominantly used swimming behavior. For the outfall drops of 20 and 26 cm, leaping behavior predominated. In a typical leaping event, fish initiated the leap near the floor of the tailwater tank and used burst swimming to propel their bodies from near the standing wave (produced by the fall of water exiting the culvert) into the culvert entrance. Both high‐ and low‐trajectory leaps were observed; some fish attained a height up to 5.2 times their body length. The average fork length of fish that were successful at culvert entry was 103 mm (SD, 1.4), compared with 101 mm (1.3) for those that remained in the tailwater pool. Within the size range of the test population, 60‐135 mm (mean, 103 mm), fish size did not affect ability to enter the culvert under the test conditions. These results indicate that juvenile coho salmon are capable of overcoming some degree of culvert perch to move upstream if tailwater pool water depth and pool size are sufficient and hydraulic passage conditions inside the culvert are favorable.
Expression and Purification of GST Fusion Proteins
Authors: Harper Sandra , Speicher David W. 
Published: May 2008

AbstractThis unit describes the use of the glutathione‐S‐transferase (GST) gene fusion system as a method for high‐level protein expression and purification from bacterial lysates. Several pGEX vectors are available with multiple cloning sites to allow for unidirectional insertion of the coding‐region DNA into the pGEX vector. The GST fusion protein is easily purified by affinity chromatography using a glutathione‐Sepharose matrix under mild conditions. Removal of the GST moiety from the protein of interest is accomplished through a specific protease cleavage site located between the GST moiety and the recombinant polypeptide. For solution digestions, GST is easily removed by a second round of chromatography on the glutathione column. Removal of proteases is facilitated by the use of a benzamidine‐Sepharose column or a gel‐filtration step. Purified protein has been used successfully in structural determinations, immunological studies, vaccine production, and structure‐function analysis of protein‐protein or DNA‐protein interactions. Curr. Protoc. Protein Sci. 52:6.6.1‐6.6.26. © 2008 by John Wiley & Sons, Inc.
Characterizing Protein‐Protein Interactions by Sedimentation Velocity Analytical Ultracentrifugation
Authors: Brown Patrick H. , Balbo Andrea , Schuck Peter 
Published: May 2008

AbstractThis unit introduces the basic principles and practice of sedimentation velocity analytical ultracentrifugation for the study of reversible protein interactions, such as the characterization of self‐association, heterogeneous association, multi‐protein complexes, binding stoichiometry, and the determination of association constants. The analytical tools described include sedimentation coefficient and molar mass distributions, multi‐signal sedimentation coefficient distributions, Gilbert‐Jenkins theory, different forms of isotherms, and global Lamm equation modeling. Concepts for the experimental design are discussed, and a detailed step‐by‐step protocol guiding the reader through the experiment and the data analysis is available as an Internet resource. Curr. Protoc. Immunol. 81:18.15.1‐18.15.39. © 2008 by John Wiley & Sons, Inc.
Direct PCR of Intact Bacteria (Colony PCR)
Authors: Woodman Michael E. 
Published: May 2008

AbstractThis protocol describes an efficient method for screening intact bacteria for the presence of desired DNA sequences using polymerase chain reaction (PCR). This method is commonly referred to as colony PCR. Curr. Protoc. Microbiol. 9:A.3D.1‐A.3D.6. © 2008 by John Wiley & Sons, Inc.
One‐Step Solvent‐Free Synthesis and Characterization of Zn1−xMnxSe@C Nanorods and Nanowires
Authors: Bhattacharyya Sayan , Perelshtein Ilana , Moshe Ofer , Rich Daniel H. , Gedanken Aharon 
Published: May 2008

AbstractThe carbon‐encapsulated, Mn‐doped ZnSe (Zn1−xMnxSe@C) nanowires, nanorods, and nanoparticles are synthesized by the solvent‐free, one‐step RAPET (reactions under autogenic pressure at elevated temperature) approach. The aspect ratio of the nanowires/nanorods is altered according to the Mn/Zn atomic ratio, with the maximum being observed for Mn/Zn = 1:20. A 10–20 nm amorphous carbon shell is evidenced from electron microscopy analysis. The replacement of Zn by Mn in the Zn1−xMnxSe lattice is confirmed by the hyperfine splitting values in the electron paramagnetic resonance (EPR) experiments. Raman experiments reveal that the Zn1−xMnxSe core is highly crystalline, while the shell consists of disordered graphitic carbon. Variable‐temperature cathodoluminescence measurements are performed for all samples and show distinct ZnSe near‐band‐edge and Mn‐related emissions. An intense and broad Mn‐related emission at the largest Mn alloy composition of 19.9% is further consistent with an efficient incorporation of Mn within the host ZnSe lattice. The formation of the core/shell nanowires and nanorods in the absence of any template or structure‐directing agent is controlled kinetically by the Zn1−xMnxSe nucleus formation and subsequent carbon encapsulation. Mn replaces Zn mainly in the (111) plane and catalyzes the nanowire growth in the [111] direction.
Incorporation of Functionalized Palladium Nanoparticles within Ultrathin Nafion Films: A Nanostructured Composite for Electrolytic and Redox‐Mediated Hydrogen Evolution
Authors: Li Fei , Bertoncello Paolo , Ciani Ilenia , Mantovani Giuseppe , Unwin Patrick R. 
Published: May 2008

AbstractA novel ultrathin Nafion‐palladium nanocomposite film is developed by incorporating positively charged Pd nanoparticles, stabilized with dimethylaminopyridine (DMAP), into Nafion Langmuir‐Schaefer (LS) films. The films show considerable activity for the redox‐catalyzed hydrogen‐evolution reaction, the rate of which scales with film thickness. The Nafion film can be deposited on both insulating (glass) and electrode (indium‐tin oxide) surfaces. The quantity of Pd nanoparticles immobilized can be controlled simply via the thickness of the Nafion film. The morphology of the films are investigated using AFM, which allows the number density of nanoparticles to be estimated for the thinnest (10 layers; 18 nm) films. Incorporation of nanoparticles is also determined with cyclic voltammetry and UV‐visible spectroscopy. The former method allows estimation of the electrochemically active surface area of Pd wired to the underlying electrode. A novel scanning electrochemical microscopy (SECM) approach is used to investigate the kinetics of the hydrogen evolution reaction (HER) catalyzed by Pd nanoparticles within the Nafion film, which allows the intrinsic activity to be determined. Single nanoparticle reactivities are extracted and are comparable to the activity of native nanoparticles on glass and to bulk Pd. It is found that neither Nafion encapsulation nor DMAP functionalization impair the electrocatalytic activity of these nanoparticles towards the HER. Nafion encapsulation thus provides a framework for the formation of interfaces, whose activity scales with film thickness. The creation of 3D materials opens up the possibility of carrying out redox‐mediated hydrogen evolution using solution species as the electron donor.
Modular Synthesis of Chiral Phosphine‐Phosphite‐Ligands from Phenolic Precursors: A New Approach to Bidentate Chelate Ligands Exploiting a PO to PC Migration Rearrangement
Authors: Velder Janna , Robert Tobias , Weidner Ingo , Neudörfl Jörg‐Martin , Lex Johann , Schmalz Hans‐Günther 
Published: May 2008

AbstractAn efficient and modular approach to bidentate phosphine‐phosphite ligands formally derived from a 6‐alkyl‐2‐phosphanylphenol, a chiral diol and phosphorus trichloride has been developed. In a key step, a borane‐protected phosphinite, prepared from an o‐bromophenol by O‐phosphanylation, is reacted with n‐butyllithium to afford the corresponding ortho‐phosphanylphenol (as the stable borane adduct) through bromine‐lithium exchange and anionic migration rearrangement. Treatment with phosphorus trichloride in the presence of a base and subsequent reaction of the in situ formed dichlorophosphite with a chiral diol (such as TADDOL or BINOL) affords the target P,P ligands in good overall yield (up to 60% over 4 steps). In contrast to an earlier approach, the new methodology is very general and tolerates bulky ortho‐substituents. The reliability of the operationally convenient protocol was demonstrated in the synthesis of a library of 16 new phosphine‐phosphite ligands, starting from different ortho‐alkylphenols. The modular concept opens a rapid access to a broad variety of ligands and might be useful in the search for and structural optimization of suitable ligands for specific chirogenic transition metal‐catalyzed transformations.
Methodological considerations in the use of salivary α‐amylase as a stress marker in field research
Authors: DeCaro Jason A. 
Published: May 2008

AbstractSalivary α‐amylase recently has been identified as a stress‐related biomarker for autonomic nervous system activity. This study addresses sample collection and handling considerations for field researchers. Saliva was collected by unstimulated passive drool from 14 adults and pooled. Incubation of pooled saliva at 22 or 37°C for 21 days did not diminish amylase activity. However, sodium azide added at concentrations ≤1.12 mg/ml to pooled saliva artificially inflated activity. After dosing cotton rolls within Salivette saliva collection devices with 0.25 to 1.5 ml of unpooled passive drool saliva from six additional adults, recovery of amylase activity was significantly below 100% at all volumes, with increased variance in recovery when the cotton was incompletely saturated (≤1.0 ml). Hence, collection by passive drool instead of cotton‐containing devices for amylase determinations is recommended, particularly whenever it is impossible to ensure full, uniform cotton saturation, and azide should be avoided as a preservative. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Incidence of lung cancer among subway drivers in Stockholm
Authors: Gustavsson Per , Bigert Carolina , Pollán Marina 
Published: May 2008

AbstractBackgroundVery high levels of airborne particles have been detected in the subway system in Stockholm. Subway particles are more toxic to DNA in cultured human lung cells than particles from ambient air.MethodsThis cohort comprised all men in Stockholm County who were gainfully employed in 1970. They were followed for cancer incidence until 1989. Lung cancer cases were identified from the national cancer register. Subway drivers were identified from the census in 1970. The reference cohort comprised all transport and communication workers in Stockholm.ResultsThere were nine cases of lung cancer among the subway drivers, giving a SIR of 0.82 (95% confidence interval 0.38–1.56).ConclusionThe lung cancer incidence was not increased among the subway drivers. The study gives some evidence against the hypothesis that subway particles would be more potent in inducing lung cancer than particles in ambient air. Am. J. Ind. Med. 51:545–547, 2008. © 2008 Wiley‐Liss, Inc.