bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potential for head injuries in infants from low-height falls
Authors: Coats Brittany , Margulies Susan S. 
Published: October 2008

Object
Falls are the most common accident scenario in young children as well as the most common history provided in child abuse cases. Understanding the biomechanics of falls provides clinicians with objective data to aid in their diagnosis of accidental or inflicted trauma. The objective of this study was to determine impact forces and angular accelerations associated with low-height falls in infants.

Methods
An instrumented anthropomorphic infant surrogate was created to measure the forces and 3D angular accelerations associated with falls from low heights (0.3–0.9 m) onto a mattress, carpet pad, or concrete.

Results
Although height significantly increased peak angular acceleration (αp), change in peak-to-peak angular velocity, time duration associated with the change in velocity, and peak impact force (Fp) for head-first drops onto a carpet pad or concrete, none of these variables were significantly affected by height when dropped onto a mattress. The αp was not significantly different for drops onto a carpet pad and concrete from 0.6 or 0.9 m due to compression of the carpet pad. Surprisingly, sagittal αp was equaled or surpassed by axial αp.

Conclusions
These are the first 3D angular acceleration and impact force data available for head impact in infants from low-height falls. A future study involving a computational model of the infant head will use the loads measured in this study to predict the probability of occipital skull fracture on impact from head-first low-height falls. Together, these studies will provide data that will aid clinicians in the evaluation of accidental and inflicted head injuries, and will contribute to the design of safer environments for children.
A Cross-Sectional Study on Production Performance of Stall Fed Dairy Cattle at Central Cattle Breeding Station (CCBS), Savar, Dhaka
Authors: Islam SKMA , Hoque MA , Alam MR , Hassan MM , Rahman MA 
Published: October 2008

To evaluate milk production performance in stall feeding dairy cattle in relation to associated biological factors such as age of cow, age of first calving, breed and number of parity at Central Cattle Breeding Station, Savar, Dhaka, a cross sectional study was performed on April, 2002 using a structured questionnaire. Local (21%), pure bred "Sahiwal" (12%) and cross bred (LÃF1; LÃF2; LÃF3; SLÃF2>) (67%) were the breed of studied cows (n = 62). The average age and milk production of the cow was 94.9 months and 3.9 liter/cow/day. The parity number and age at first calving of a cow were recorded to be average 4 and 43 months respectively. The younger cows (â¤99 months) were 6.7 time more likely to have yielded >3 liters/cow/day than the older cows (>99 months) (p < 0.001). Cows with â¤4 parities were recorded to have 7.6 times more chance to produce milk of >3 liters/cow/day than cows with â¥4 parities (10.9%) (p < 0.001)). The milk production of >3 liters/cow/day is 39.3 times higher in the crossbred than the milk production in the local breed (p < 0.001). Keywords: Milk production, potential factors (age, age at first calving, breed, genotype and parity), dairy cattle Â doi:10.3329/bjvm.v4i1.1527 Bangl. J. Vet. Med. (2006). 4 (1): 61-63
Antinociceptive Effect of the Crude Ethanolic Extract of <i>Crataeva nurvala</i>. Buch. on Mice
Authors: Alam MA , Haque ME , Shilpi JA , Daulla KA 
Published: October 2008

In order to scientifically appraise some of the anecdotal, folkloric, ethnomedical uses of (Bengali name - borun), the present study was undertaken to investigate the antinociceptive properties of the ethanolic extracts of Crataeva nurvala on mice in the Phytochemistry and Pharmacology Laboratory, Pharmacy Discipline, Khulna University, Khulna, during the period from December 2003 to February 2004. The antinociceptive effect of crude ethanolic extracts was evaluated by âacetic acid' analgesic test method in mice. Crude ethanolic extracts of Crataeva nurvala (250-500 mg/kg PO) produced dose-dependent, significant (p < 0.05-0.001) antinociceptive effect against chemically induced nociceptive pain stimuli in mice. The results obtained in this study suggest that the antinociceptive effect of the extracts of Crataeva nurvala are peripherally and centrally-mediated. The findings of this experimental animal study indicate that crude ethanolic extracts of Crataeva nurvala possesses antinociceptive properties and thus lend pharmacological support to folkloric, anecdotal uses of âborun' in the treatment and/or management of painful, arthritic inflammatory conditions. Key Words: Antinociceptive, Crataeva nurvala, diclofenac sodium, writhing Â doi:10.3329/bjvm.v4i1.1528 Bangl. J. Vet. Med. (2006). 4 (1): 65-68
Dynamic Mechanical Analysis of Polymers and Rubbers
Authors: Menard Kevin P. , Bilyeu Bryan W. 
Published: October 2008

AbstractDynamic mechanical analysis (DMA) is the technique of applying a stress or strain to a sample and analyzing the response to obtain phase angle and deformation data. These data allow the calculation of the damping or tan δ; the storage, loss, and complex modulus; as well as complex viscosity and complex compliance. Two approaches are used: (i) forced frequency, where the signal is applied at a set frequency and (ii) free resonance, where the material is perturbed and allowed to exhibit free resonance decay. Most modern DMA instruments are of the forced resonance type. In both approaches, the technique is very sensitive to the motions of the polymer chains and it is a powerful tool for measuring transitions in polymers. It is estimated to be 100 times more sensitive to the glass transition than differential scanning calorimetry (DSC) and resolves other more localized transitions not detected in DSC. In addition, the technique allows the rapid scanning of a material's modulus and viscosity as a function of temperature or frequency. DMA may also be referred to as dynamic mechanical thermal analysis (DMTA), dynamic mechanical spectroscopy (DMS), or dynamic thermomechanical analysis (DTMA).
Neutron Radiography for the Analysis of Plant–Soil Interactions
Authors: Robinson Brett H. , Moradi Ahmad , Schulin Rainer , Lehmann Eberhard , Kaestner Anders 
Published: October 2008

Abstract
Neutron radiography (NR) can be used to quantify the spatial distribution of water in the soil–plant system with high precision and good spatial resolution. This property of neutron imaging results from the high interaction probability of hydrogen nuclei with slow neutrons. If there is a sufficient difference between the water content of the soil and roots, neutron radiographs can reveal plant roots and show root development. NR is noninvasive, and the radiation dose needed to image plant roots in soil does not affect plant development. Quantification of the soil's water content often requires correction for neutron‐scattering artifacts. Root visibility is proportional to root thickness, and is inversely related to the width of the sample container and the water and organic matter contents of the ambient soil. Ideally, the soil should have low organic matter content and low water content but still permit the normal development of plant roots. Currently, the availability of neutron‐imaging facilities limits the widespread application of NR to soil and root studies. However, technological development and increased investment will result in NR becoming a standard method for some soil–plant analyses.
Terahertz Spectroscopy
Authors: Wilke Ingrid 
Published: October 2008

Abstract
Terahertz spectroscopy has attracted great interest in recent years due to the development of improved terahertz radiation sources and terahertz radiation detectors as well as novel terahertz spectroscopy systems. This article discusses Fourier transform far‐infrared spectroscopy, backward‐wave oscillator terahertz spectroscopy, and time‐domain terahertz spectroscopy. Terahertz spectroscopy is spectroscopy with electromagnetic radiation in the terahertz (THz) frequency range. THz radiation is invisible. The THz frequency range is located between microwaves and the infrared. THz spectroscopy measures the dielectric properties of liquid and solid as well as inorganic and organic materials in the THz frequency range. Furthermore, THz spectroscopy is a method for vibrational and rotational spectroscopy of gases.
Specifications and merits of Far‐infrared Fourier transform spectroscopy, backward‐wave oscillator terahertz spectroscopy, and time‐domain terahertz spectroscopy for applications in analytical chemistry are compared. The frequency range, frequency resolution, and dynamic range of each method are discussed. Various measurement modalities such as transmission and reflection spectroscopy, phase‐sensitive spectroscopy, and time‐resolved THz spectroscopy are explained. The physical measurement principle of each method is discussed. The relationship between the measurement observed and the dielectric function of a material are presented for each method. Technical descriptions of the methods are provided. An overview on specific applications of THz spectroscopy is presented.
UV curing kinetics and mechanism of a highly branched polycarbosilane
Authors: Li Houbu , Zhang Litong , Cheng Laifei , Kang Haitao , Wang Yiguang 
Published: October 2008

AbstractThe UV curing process in both air and nitrogen atmosphere for the highly branched polycarbosilane system was investigated by differential scanning photo calorimeter. The UV cured products were characterized by Fourier‐transform infrared spectrometry (FTIR). By comparison with the FTIR results of the uncured liquid mixture and the cured samples, the possible cross‐linking reactions were determined. The kinetics of the curing systems was studied. The rate constant k was calculated based on the experimental results. The activation energies in different curing conditions were obtained. According to these results, it was learned that the mechanism for the UV curing in nitrogen was controlled by the photolysis of photoinitiator. Comparably, the UV curing process in air was complicated. It was affected by not only the photolysis of photoinitiator, but also oxygen and tripropane glycol diacrylate. Copyright © 2008 John Wiley & Sons, Ltd.
Tensile and elastic properties of triblock copolymer based on aramide end‐segments and polyether mid‐segments
Authors: Arun Araichimani , Gaymans Reinoud J. 
Published: October 2008

AbstractThe tensile and elastic behavior of triblock copolymers containing uniform aramide (TΦB) hard end‐segments (HS) and poly(tetramethylene oxide) (PTMO, Mn = 2900 g/mol) soft segments (SSs) was studied. The molecular weight of the copolymer was varied by changing the length of the soft mid‐segment; by extending the PTMO2900 with terephthalate units, the SS length was increased from 2900 g/mol to 21,000 g/mol and concurrently the aramide concentration decreased from 18 to 3 wt %. The mechanical properties were investigated by means of tensile testing, stress relaxation (SR) experiments, and cyclic tensile set (TS) tests. The E‐modulus was found to increase with increasing aramide content. The low molecular weight copolymers were brittle whereas the high molecular weight copolymers displayed large fracture strain values. The transition from brittle to ductile seemed to occur at a triblock copolymer molecular weight of 6600 g/mol. A strain‐induced crystallization was observed at strains above 250%, and both the fracture strain and stress were found to be highly dependant on the molecular weight of the copolymer. Cyclic tensile experiments showed that the materials had low TS values up to the strain hardening point. On the other hand, the SR data at 10% strain seemed to be little dependant on the molecular weight. The higher molecular weight copolymers did not display lower SR values than their low molecular weight counterparts. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Poly(acrylamide/laponite) nanocomposite hydrogels: Swelling and cationic dye adsorption properties
Authors: Li Peng , Siddaramaiah  , Kim Nam Hoon , Yoo Gye‐Hyoung , Lee Joong‐Hee 
Published: October 2008

AbstractSuper adsorbent polyacrylamide (PAAm)/nanoclay (laponite, Lap) hydrogels were prepared by in situ free radical polymerization of AAm in an aqueous solution with clay as a crosslinker. The swelling properties and water‐soluble cationic dye adsorption behaviors of the PAAm/laponite (PAAm/Lap) nanocomposite (NC) hydrogels were investigated. The parameters of swelling and diffusion of water in dye solutions were evaluated for the PAAm/Lap NC hydrogels. The adsorption behavior of the monovalent cationic dyes such as Basic Blue 12 (BB 12), Basic Blue 9 (BB 9), and Basic Violet 1 (BV 1), were studied on the NC hydrogels. The effects of the clay content of the hydrogel on its cationic dye uptake behavior were studied. The adsorption studies indicated that the rates of dye uptake by the NC hydrogels increased in the following order: BB 9 > BB 12 > BV 1. This order is similar to the swelling results of the PAAm/Lap NC hydrogel in the dye solutions. The equilibrium uptakes of the different dyes by the PAAm/Lap NC hydrogel were nearly the same. In the dye absorption studies, S‐type adsorption in the Giles classification system was found for the BB 12 and BV 1 dyes, whereas L‐type was observed for the BB 9 dye. After the heat treatment of PAAm/Lap, the rate of dye uptake and equilibrium dye uptake were increased. The NC hydrogels may be considered as a good candidate for environmental applications to retain more water and to remove dyes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of new polyamides derived from 1,3‐(4‐carboxy phenoxy) propane and aromatic diamines
Authors: Nasr‐Isfahani Hossein , Faghihi Khalil , Valikhani Nasim 
Published: October 2008

AbstractSix new polyamides 5a‐f containing flexible trimethylene segments in the main chain were synthesized through the direct polycondensation reaction of 1,3‐(4‐carboxy phenoxy) propane 3 with six derivatives of aromatic diamines 4a‐f in a medium consisting of N‐methyl‐2‐pyrrolidone, triphenyl phosphite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel polyamides containing flexible trimethylene segments in the main chain in high yield with inherent viscosities between 0.32 and 0.68 dL/g. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis (TGA) and differential thermal gravimetric (DTG). The glass‐transition temperatures of these polyamides were recorded between 165 and 190°C by differential scanning calorimetry, and the 10% weight loss temperatures were ranging from 360 to 430°C under nitrogen. 1,3‐(4‐Carboxy phenoxy) propane 3 was prepared from the reaction of 4‐hydroxy benzoic acid 1 with 1,3‐dibromo propane 2 in the presence of NaOH solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
New Mechanistic Insight in the Thermal Helix Inversion of Second‐Generation Molecular Motors
Authors: Klok Martin , Walko Martin , Geertsema Edzard M. , Ruangsupapichat Nopporn , Kistemaker Jos C. M. , Meetsma Auke , Feringa Ben L. 
Published: October 2008

AbstractThe introduction of dibenzocyclohepten‐5‐ylidene as part of a unidirectional light‐driven molecular motor allows a more complete picture of the pathway of thermal helix inversion to be developed. The most stable conformation is similar to that found in related motors in that it has, overall, an anti‐folded structure with the substituent at the stereogenic centre adopting an axial orientation. Photochemical cis/trans isomerisation at −40 °C results in the formation of an isomer in a syn‐folded conformation with the methyl group in an axial orientation. This contrasts with previous studies on related molecular rotary motors. The conformation of the higher energy intermediate typically observed for this class of compound is the anti‐folded conformation, in which the methyl group is in an equatorial orientation. This conformation is available through an energetically uphill upper half ring inversion of the observed photochemical product. However, this pathway competes with a second process that leads to the more stable anti‐folded conformation in which the methyl group is oriented axially. It has been shown that the conformations and pathways available for second‐generation molecular motors can be described by using similar overall geometries. Differences in the metastable high‐energy species are attributable to the relative energy and position on the reaction coordinate of the transition states. Kinetic studies on these new molecular motors thus provide important insights into the conformational dynamics of the rotation cycle.
Synthesis and Cannabinoid Receptor Activity of Ketoalkenes from Echinacea pallida and Nonnatural Analogues
Authors: Egger Michael , Pellett Patrina , Nickl Kathrin , Geiger Sarah , Graetz Stephanie , Seifert Roland , Heilmann Jörg , König Burkhard 
Published: October 2008

AbstractDespite its popularity and widespread use, the efficacy of Echinacea products remains unclear and controversial. Among the various compounds isolated from Echinacea, ketoalkenes and ketoalkenynes exclusively found in the pale purple coneflower (E. pallida) are major components of the extracts. In contrast to E. purpurea alkamides, these compounds have not been synthesized and studied for immunostimulatory effects. We present a practical and useful synthetic approach to the ketoalkenes using palladium‐catalyzed cross‐coupling reactions and the pharmaceutical results at the human cannabinoid receptors. The synthetic route developed provides overall good yields for the ketoalkenes and is applicable to other natural products with similar 1,4‐diene motifs. No significant activity was observed at either receptor, indicating that the ketoalkenes from E. pallida are not responsible for immunomodulatory effects mediated via the cannabinergic system. However, newly synthesized non‐natural analogues showed micro‐molar potency at both cannabinoid receptors.
Asymmetric 1,4‐Addition of Oxazolones to Nitroalkenes by Bifunctional Cinchona Alkaloid Thiourea Organocatalysts: Synthesis of α,α‐Disubstituted α‐Amino Acids
Authors: Alemán José , Milelli Andrea , Cabrera Silvia , Reyes Efraim , Jørgensen Karl Anker 
Published: October 2008

AbstractAn easy and simple synthetic approach to optically active α,α‐quaternary α‐amino acids using asymmetric organocatalysis is presented. The addition of oxazolones to nitroalkenes catalyzed by thiourea cinchona derivatives provides the corresponding α,α‐quaternary α‐amino acid derivatives with good yields, excellent diastereoselectivities (up to 98 % dr), and from moderate to good enantioselectivities (up to 92 % ee). The reaction can be performed on a large scale. The optically active oxazolone–nitroalkene addition products can be opened in a one‐pot reaction to the corresponding ester–amide derivatives. Additional transformations are also presented, such as the synthesis of amino esters, amino acids, and transformation into 3,4‐disubstituted pyrrolidin‐2‐ones.
High‐performance liquid chromatographic chiral separation of β2‐homoamino acids
Authors: Pataj Zoltán , Berkecz Robert , Ilisz István , Misicka Aleksandra , Tymecka Dagmara , Fülöp Ferenc , Armstrong Daniel W. , Péter Antal 
Published: October 2008

AbstractReversed‐phase high‐performance liquid chromatographic methods were developed for the separation of enantiomers of eleven unnatural β2‐homoamino acids on chiral stationary phases containing macrocyclic glycopeptides (teicoplanin‐containing Chirobiotic T and T2) or the macrocyclic peptide teicoplanin aglycone (Chirobiotic TAG) as chiral selectors. The effects of the organic modifier, the mobile phase composition, temperature, and the structures of the analytes on the separations were investigated. Separations were carried out at constant mobile phase compositions in temperature range 7–45°C and the changes in enthalpy, Δ(ΔH°), entropy, Δ(ΔS°), and free energy, Δ(ΔG°), were calculated. The −Δ(ΔG°) values obtained on the three columns indicated that Chirobiotic TAG, without sugar units, may promote the interactions of the enantiomers of β2‐homoamino acids with branched alkyl or aryl side‐chains, whereas for β2‐homoamino acids with alkyl side‐chains Chirobiotic T and T2 seem to be more favorable. The elution sequence was determined in some cases and was observed to be R < S. Chirality, 2009. © 2008 Wiley‐Liss, Inc.
Modeling of the Intestinal Peptide Transporter hPepT1 and Analysis of Its Transport Capacities by Docking and Pharmacophore Mapping
Authors: Pedretti Alessandro , De Luca Laura , Marconi Cristina , Negrisoli Gianpaolo , Aldini Giancarlo , Vistoli Giulio 
Published: October 2008

AbstractAn early pharmacokinetic screen for peptidomimetic drugs should have the ability to predict molecules with high affinity for intestinal transporters, as peptide‐like derivatives are seldom absorbed passively. Hence, the first objective of this study was to generate a reliable model for the structure of the hPepT1 protein, which is the main intestinal transporter involved in the absorption of both dietary peptides and peptidomimetics. The modeling was based on the resolved structure of the homologous bacterial lactose permease LacY using a fragmental strategy. The interaction capacities of the hPepT1 model were explored by docking a set of 50 known ligands. Despite the known predilection of hPepT1 for hydrophobic ligands, docking results unveiled the key role of the polar interactions stabilized by charged termini, especially concerning the ammonium head group. The docking results were further verified by developing a pharmacophore model that confirmed the key features required for optimal hPepT1 affinity. The consistency of the docking results and the agreement with the pharmacophore model afford an encouraging validation for the proposed model and suggest that it can be exploited to design peptide‐like molecules with an improved affinity for such a transporter.
IRMPD Spectroscopy of a Protonated, Phosphorylated Dipeptide
Authors: Correia Catarina F. , Clavaguera Carine , Erlekam Undine , Scuderi Debora , Ohanessian Gilles 
Published: October 2008

AbstractThe protonated, phosphorylated dipeptide [GpY+H]+ is characterized by mid‐infrared multiple‐photon dissociation (IRMPD) spectroscopy and quantum‐chemical calculations. The ions are generated in an external electrospray source and analyzed in a Fourier transform ion cyclotron resonance mass spectrometer, and their fragmentation is induced by resonant absorption of multiple photons emitted by a tunable free‐electron laser. The IRMPD spectra are recorded in the 900–1730 cm−1 range and compared to the absorption spectra computed for the lowest energy structures. A detailed calibration of computational levels, including B3LYP‐D and coupled cluster, is carried out to obtain reliable relative energies of the low‐energy conformers. It turns out that a single structure can be invoked to assign the IRMPD spectrum. Protonation at the N terminus leads to the formation of a strong ionic hydrogen bond with the phosphate PO group in all low‐energy structures. This leads to a PO stretching frequency for [GpY+H]+ that is closer to that of [pS+H]+ than to that of [pY+H]+ and thus demonstrates the sensitivity of this mode to the phosphate environment. The COP phosphate ester stretching mode is confirmed to be an intrinsic diagnostic for identification of which type of amino acid is phosphorylated.