bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of cationic guar gum: A high performance flocculating agent
Authors: Pal Sagar , Mal D. , Singh R. P. 
Published: May 2007

AbstractAmong various water‐soluble polysaccharides, guar gum is one of the most important polysaccharide, which is having a wide variety of applications. By grafting a cationic moiety onto the backbone of guar gum, a modified naturally occurring polysaccharide can be developed, which used to be use as high performance flocculating agent and viscosifier (Singh et al.).15 Various grades of cationic guar gums have been synthesized by varying the synthesis parameters. All these polysaccharides have been characterized by various characterization techniques, such as elemental analysis, FTIR spectroscopy, intrinsic viscosity measurement, molecular weight determination, thermal analysis, and X‐ray diffraction analysis. From all of these characterization studies, it has been confirmed that the cationic moiety has been grafted onto the backbone of polysaccharide. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Thermal conductivity models for carbon/liquid crystal polymer composites
Authors: Keith Jason M. , King Julia A. , Lenhart Kara M. , Zimny Bridget 
Published: May 2007

AbstractThermally conductive resins are needed for bipolar plates in fuel cells. Currently, the materials used for these bipolar plates often contain a single type of graphite in a thermosetting resin. In this study, varying amounts of four different types of polyacrylonitrile carbon fillers (Ketjenblack carbon black, Thermocarb synthetic graphite, Fortafil 243 carbon fiber, and Panex 30 carbon fiber) were added to a thermoplastic matrix (Vectra A950RX Liquid Crystal Polymer), with the resulting resins tested for through‐plane and in‐plane thermal conductivity. There are two unique contributions of this work. The first contribution is the use of the Nielsen model for the through‐plane thermal conductivity as a function of the single filler volume fraction. The model fits the data for all composites well. The second contribution is the development of a new, accurate, empirical model to predict the in‐plane thermal conductivity for all resins containing synthetic graphite or carbon fiber. Both of these models will form the basis for the development of new thermal conductivity models for composites with multiple fillers for fuel cell bipolar plate applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Evolution of hyperphalangy and digit reduction in the cetacean manus
Authors: Cooper Lisa Noelle , Berta Annalisa , Dawson Susan D. , Reidenberg Joy S. 
Published: May 2007

AbstractCetaceans (whales, dolphins, and porpoises) have a soft tissue flipper that encases most of the forelimb, and elongated digits with an increased number of phalanges (hyperphalangy). In addition, some cetaceans exhibit a reduction in digit number. Although toothed cetaceans (odontocetes) are pentadactylous, most baleen whales (mysticetes) are tetradactylous and also lack a metacarpal. This study conducts a survey of cetacean metacarpal and phalangeal morphologies, traces the evolution of hyperphalangy in a phylogenetic context, optimizes characters onto previously published cetacean phylogenies, and tests various digit loss hypotheses. Dissections were performed on 16 cetacean flippers representing 10 species (8 mysticetes, 2 odontocetes). Phalangeal count data were derived from forelimb radiographs (36 odontocetes, 5 mysticetes), osteological specimens of articulated forelimbs (8 mysticetes), and were supplemented with published counts. Modal phalangeal counts were coded as ordered and unpolarized characters and optimized onto two known cetacean phylogenies. Results indicate that digital ray I is reduced in many cetaceans (except Globicephala) and all elements of digital ray I were lost in tetradactylous mysticetes. Fossil evidence indicates this ray may have been lost approximately 14 Ma. Most odontocetes also reduce the number of phalangeal elements in digit V, while mysticetes typically retain the plesiomorphic condition of three phalanges. Results from modal phalangeal counts show the greatest degree of hyperphalangy in digits II and III in odontocetes and digits III and IV in mysticetes. Fossil evidence indicates cetacean hyperphalangy evolved by at least 7–8 Ma. Digit loss and digit positioning may underlie disparate flipper shapes, with narrow, elongate flippers facilitating fast swimming and broad flippers aiding slow turns. Hyperphalangy may help distribute leading edge forces, and multiple interphalangeal joints may smooth leading edge flipper contour. Anat Rec, 290:654–672, 2007. © 2007 Wiley‐Liss, Inc.
Stomach anatomy and use in defining systemic relationships of the cetacean family ziphiidae (beaked whales)
Authors: Mead James G. 
Published: May 2007

AbstractMembers of the Cetacean family Ziphiidae (Beaked whales) exhibit surprising diversity in stomach anatomy, particularly in the number of connecting chambers between the main and pyloric stomachs. Sixty‐one stomachs of five beaked whale species were examined, including Berardius, Hyperoodon, Mesoplodon, Tasmacetus, and Ziphius. Specimens were obtained post mortem from beach‐stranded individuals, with the exception of 30 Berardius specimens that were taken at a whaling station in Japan. Most specimens were collected by the Marine Mammal Program of the National Museum of Natural History, with the exception of one specimen of Mesoplodon steinegeri, which from the Los Angeles County Museum and one specimen of Tasmacetus from the Museum of New Zealand. Additional data are included from published accounts. A single species was examined for all of the genera but Mesoplodon, where there was material for 7 of 13 known species. The sample of Berardius bairdii was sufficient (n = 30) to determine species‐specific variation in compartment counts. Chamber anatomy was explored by means of manual palpation. Results indicate that ziphiid stomachs can be separated into at least three principal groups: generalized ziphiid stomach (one main stomach, one pyloric stomach), derived stomach type I (two main stomachs, one pyloric stomach), and derived stomach type II (two main stomachs, two pyloric stomachs). Generalized stomachs are found in Hyperoodon, Tasmacetus, Ziphius, Mesoplodon densirostris, M. perrini, and M. stejnegeri. Derived stomachs of type I are found in Berardius, and of type II are found in Mesoplodon bidens, M. europaeus, and M. mirus. The ziphiids clearly form a distinct group of cetaceans in their utilization of differences in stomach morphology. These anatomical differences may serve to elucidate systematic relationships among the ziphiids. Further study is necessary to establish whether these differences correlate with specialized adaptations related to an aquatic environment. Anat Rec, 290:581–595, 2007. © 2007 Wiley‐Liss, Inc.
Anatomical adaptations of aquatic mammals
Authors: Reidenberg Joy S. 
Published: May 2007

AbstractThis special issue of the Anatomical Record explores many of the anatomical adaptations exhibited by aquatic mammals that enable life in the water. Anatomical observations on a range of fossil and living marine and freshwater mammals are presented, including sirenians (manatees and dugongs), cetaceans (both baleen whales and toothed whales, including dolphins and porpoises), pinnipeds (seals, sea lions, and walruses), the sea otter, and the pygmy hippopotamus. A range of anatomical systems are covered in this issue, including the external form (integument, tail shape), nervous system (eye, ear, brain), musculoskeletal systems (cranium, mandible, hyoid, vertebral column, flipper/forelimb), digestive tract (teeth/tusks/baleen, tongue, stomach), and respiratory tract (larynx). Emphasis is placed on exploring anatomical function in the context of aquatic life. The following topics are addressed: evolution, sound production, sound reception, feeding, locomotion, buoyancy control, thermoregulation, cognition, and behavior. A variety of approaches and techniques are used to examine and characterize these adaptations, ranging from dissection, to histology, to electron microscopy, to two‐dimensional (2D) and 3D computerized tomography, to experimental field tests of function. The articles in this issue are a blend of literature review and new, hypothesis‐driven anatomical research, which highlight the special nature of anatomical form and function in aquatic mammals that enables their exquisite adaptation for life in such a challenging environment. Anat Rec, 290:507–513, 2007. © 2007 Wiley‐Liss, Inc.
Evolution of marine mammals: Back to the sea after 300 million years
Authors: Uhen Mark D. 
Published: May 2007

AbstractThe fossil record demonstrates that mammals re‐entered the marine realm on at least seven separate occasions. Five of these clades are still extant, whereas two are extinct. This review presents a brief introduction to the phylogeny of each group of marine mammals, based on the latest studies using both morphological and molecular data. Evolutionary highlights are presented, focusing on changes affecting the sensory systems, locomotion, breathing, feeding, and reproduction in Cetacea, Sirenia, Desmostylia, and Pinnipedia. Aquatic adaptations are specifically cited, supported by data from morphological and geochemical studies. For example, analysis of oxygen isotopes incorporated into fossil tooth enamel indicates whether these mammals foraged in (and, therefore, ingested) fresh water or sea water. Comparisons between groups are made to see if there are any common patterns, particularly relating to adaptations to aquatic life. Results show that aquatic characteristics evolved in mosaic patterns and that different morphological solutions to aquatic conditions were achieved separately in each of these groups. Changes in the axial and appendicular skeleton assist with locomotion for aquatic foraging. Nostril and eye placement modifications accommodate wading versus underwater foraging needs. All groups exhibit aquatic adaptations directly related to feeding, particularly changes in the dentition and rostrum. The earliest representatives of these clades all show morphological features that indicate they were feeding while in the water, suggesting that feeding ecology is a key factor in the evolution of marine mammals. Anat Rec, 290:514–522, 2007. © 2007 Wiley‐Liss, Inc.
Examination of the three‐dimensional geometry of cetacean flukes using computed tomography scans: Hydrodynamic implications
Authors: Fish Frank E. , Beneski John T. , Ketten Darlene R. 
Published: May 2007

AbstractThe flukes of cetaceans function in the hydrodynamic generation of forces for thrust, stability, and maneuverability. The three‐dimensional geometry of flukes is associated with production of lift and drag. Data on fluke geometry were collected from 19 cetacean specimens representing eight odontocete genera (Delphinus, Globicephala, Grampus, Kogia, Lagenorhynchus, Phocoena, Stenella, Tursiops). Flukes were imaged as 1 mm thickness cross‐sections using X‐ray computer‐assisted tomography. Fluke shapes were characterized quantitatively by dimensions of the chord, maximum thickness, and position of maximum thickness from the leading edge. Sections were symmetrical about the chordline and had a rounded leading edge and highly tapered trailing edge. The thickness ratio (maximum thickness/chord) among species increased from insertion on the tailstock to a maximum at 20% of span and then decreasing steadily to the tip. Thickness ratio ranged from 0.139 to 0.232. These low values indicate reduced drag while moving at high speed. The position of maximum thickness from the leading edge remained constant over the fluke span at an average for all species of 0.285 chord. The displacement of the maximum thickness reduces the tendency of the flow to separate from the fluke surface, potentially affecting stall patterns. Similarly, the relatively large leading edge radius allows greater lift generation and delays stall. Computational analysis of fluke profiles at 50% of span showed that flukes were generally comparable or better for lift generation than engineered foils. Tursiops had the highest lift coefficients, which were superior to engineered foils by 12–19%. Variation in the structure of cetacean flukes reflects different hydrodynamic characteristics that could influence swimming performance. Anat Rec, 290:614–623, 2007. © 2007 Wiley‐Liss, Inc.
Host‐induced ecdysteroids in the stop‐and‐go oogenesis in a synovigenic parasitoid wasp
Authors: Bodin Aurélie , Jaloux Bruno , Mandon Nicole , Vannier Fabrice , Delbecque Jean‐Paul , Monge Jean‐Paul , Mondy Nathalie 
Published: May 2007

AbstractEupelmus vuilleti (Hymenoptera; Eupelmidae) is a solitary ectoparasitoid producing yolk‐rich eggs. The female oviposits mainly on the fourth larval instar of Callosobruchus maculatus (Coleoptera; Bruchidae), which develop within pods and seeds of Vigna unguiculata (Fabacae). Parasitoid females are synovigenic, i.e., they are born with immature eggs and need to feed from the host to sustain egg production during their entire lifetime. However, eggs are rapidly resorbed in unfavourable conditions and an efficient stop‐and‐go mechanism controls oogenesis in such animals. In this study, the possible involvement of ecdysteroids in the regulation of parasitoid oogenesis is examined. In a first step, the identity and titre of ecdysteroids in reproductively active and inactive female parasitoids were investigated by high performance liquid chromatography followed by enzyme immuno‐assay (EIA/HPLC). A larger secretion of ecdysone was found in female during their reproductive period compared with inactive females. In a second step, both the secretion of ecdysteroids into the medium of in vitro incubated ovaries and the ecdysteroid content of females reared with or without host were measured (EIA). The presence of the host, which represents both the oviposition site and the nutritional source, induced an active biosynthesis of ecdysone. This synthesis started at a slow rate after host introduction and reached a maximum after 48 h. When hosts were available, this synthesis was cyclic and continuous during the entire female lifetime. These results showed that host presence triggered ovarian synthesis of ecdysteroids, which are involved in a stop‐and‐go regulation of egg production linked to host availability. Arch. Insect Biochem. Physiol. 65:103–111, 2007. © 2007 Wiley‐Liss, Inc.
Synthesen mit Cyanessigsäure, III. Zur Reaktion von 2‐Hydroxy‐benzaldehyd mit Cyanacetamid und Malodinitril
Authors: Schiemenz Günter Paulus 
Published: May 2007

AbstractBei den bisher als 2‐Hydroxy‐α‐cyan‐zimtsäure‐amid und ‐nitril formulierten Verbindungen handelt es sich um das Amid und Nitril der Cumarinimid‐carbonsäure‐(3).
Phosphororganische Verbindungen, XXXII. Enthalogenierung von Phenolen und aromatischen Aminen. Austausch phenolischer hydroxylgruppen gegen Chlor
Authors: Horner Wippel Hellmut Hoffmann, Leopold Hans G. , Michael Dieter 
Published: May 2007

AbstractAromatische o‐und p‐Bromamine bilden mit Triphenylphosphin Phosphinimidhydrobromide. Aus o‐und p‐Brom‐phenolen und Triphenylphosphin werden Aryloxy‐triphenyl‐phosphoniumsalze erhalten, welche hydrolytisch außerordentlich leicht in Phenole und Triphenylphosphinoxyd aufgespalten werden. Bei ihrer thermischen Spaltung entstehen Arylhalogenide. Arylchloride bilden sich daher auch beim Erhitzen aromatischer hydroxyverbindungen mit Triphenylphosphin‐dichlorid oder Diphenyltrichlorphosphoran.
Infrarotspektren von S‐Oxyden und S‐Dioxyden Cyclischer Mercaptole
Authors: Otting Walter , Neugebauer Franz Alfred 
Published: May 2007

AbstractBei den S‐Oxyden und S‐Dioxyden von 2.2‐disubstituierten 1.3‐Dithiolanen und 1.3‐Dithianen wurden für die So‐banden folgende Frequenzbereiche [cm‐1] gefunden: magnified image Auf Grund spektrosktroskopischer Regelmäßigkeiten ist von den 2.2‐Diphenyl 1.3‐dithiolan‐1.3‐dioxyden das Isomere mit dem höheren Schmelzpunkt die trans From, dasjenige mit dem tieferen die cis‐Form. Bei den Isomeren des 2.2‐Diphenyl1‐1.3‐dithian‐1.3‐dioxyds ist es umgekehrt.
Polyacetylenverbindungen, XXXVI. Über neue Polyintypen aus Chrysanthemum frutescens L.
Authors: Bohlmann Ferdinand , Klieine Käthe‐Marie 
Published: May 2007

AbstractAus den Wurzeln von Chrysanthemum frutescens L. werden 5 neue Polyine isoliert und in ihrer Konstitution aufgeklärt. In allen Fällen handelt es sich um o‐Methoxybenzoesäureester, die in 6‐Stellung verschieden substituierte Seitenketten mit Diacetylengruppierung enthalten. Zwei dieser Verbindungen haben überraschenderweise eine Acetylenwasserstoff‐Endgruppe.
Rescue of Degradation‐Prone Mutants of the FK506‐Rapamycin Binding (FRB) Protein with Chemical Ligands
Authors: Stankunas Kryn , Bayle J. Henri , Havranek James J. , Wandless Thomas J. , Baker David , Crabtree Gerald R. , Gestwicki Jason E. 
Published: May 2007

AbstractWe recently reported that certain mutations in the FK506‐rapamycin binding (FRB) domain disrupt its stability in vitro and in vivo (Stankunas et al. Mol. Cell, 2003, 12, 1615). To determine the precise residues that cause instability, we calculated the folding free energy (ΔG) of a collection of FRB mutants by measuring their intrinsic tryptophan fluorescence during reversible chaotropic denaturation. Our results implicate the T2098L point mutation as a key determinant of instability. Further, we found that some of the mutants in this collection were destabilised by up to 6 kcal mol−1 relative to the wild type. To investigate how these mutants behave in cells, we expressed firefly luciferase fused to FRB mutants in African green monkey kidney (COS) cell lines and mouse embryonic fibroblasts (MEFs). When unstable FRB mutants were used, we found that the protein levels and the luminescence intensities were low. However, addition of a chemical ligand for FRB, rapamycin, restored luciferase activity. Interestingly, we found a roughly linear relationship between the ΔG of the FRB mutants calculated in vitro and the relative chemical rescue in cells. Because rapamycin is capable of simultaneously binding both FRB and the chaperone, FK506‐binding protein (FKBP), we next examined whether FKBP might contribute to the protection of FRB mutants. Using both in vitro experiments and a cell‐based model, we found that FKBP stabilizes the mutants. These findings are consistent with recent models that suggest damage to intrinsic ΔG can be corrected by pharmacological chaperones. Further, these results provide a collection of conditionally stable fusion partners for use in controlling protein stability.
Predicting and Tuning Physicochemical Properties in Lead Optimization: Amine Basicities
Authors: Morgenthaler Martin , Schweizer Eliane , Hoffmann‐Röder Anja , Benini Fausta , Martin Rainer E. , Jaeschke Georg , Wagner Björn , Fischer Holger , Bendels Stefanie , Zimmerli Daniel , Schneider Josef , Diederich François , Kansy Manfred , Müller Klaus 
Published: May 2007

AbstractThis review describes simple and useful concepts for predicting and tuning the pKa values of basic amine centers, a crucial step in the optimization of physical and ADME properties of many lead structures in drug‐discovery research. The article starts with a case study of tricyclic thrombin inhibitors featuring a tertiary amine center with pKa values that can be tuned over a wide range, from the usual value of around 10 to below 2 by (remote) neighboring functionalities commonly encountered in medicinal chemistry. Next, the changes in pKa of acyclic and cyclic amines upon substitution by fluorine, oxygen, nitrogen, and sulfur functionalities, as well as carbonyl and carboxyl derivatives are systematically analyzed, leading to the derivation of simple rules for pKa prediction. Electronic and stereoelectronic effects in cyclic amines are discussed, and the emerging computational methods for pKa predictions are briefly surveyed. The rules for tuning amine basicities should not only be of interest in drug‐discovery research, but also to the development of new crop‐protection agents, new amine ligands for organometallic complexes, and in particular, to the growing field of amine‐based organocatalysis.
Parameterization of Peptide 13C Carbonyl Chemical Shielding Anisotropy in Molecular Dynamics Simulations
Authors: Jordan Daniel M. , Mills K. Maria , Andricioaei Ioan , Bhattacharya Akash , Palmo Kim , Zuiderweg Erik R. P. 
Published: May 2007

AbstractNMR chemical shielding anisotropy (CSA) relaxation is an important tool in the study of dynamical processes in proteins and nucleic acids in solution. Herein, we investigate how dynamical variations in local geometry affect the chemical shielding anisotropy relaxation of the carbonyl carbon nucleus, using the following protocol: 1) Using density functional theory, the carbonyl 13C′ CSA is computed for 103 conformations of the model peptide group N‐methylacetamide (NMA). 2) The variations in computed 13C′ CSA parameters are fitted against quadratic hypersurfaces containing cross terms between the variables. 3) The predictive quality of the CSA hypersurfaces is validated by comparing the predicted and de novo calculated 13C′ CSAs for 20 molecular dynamics snapshots. 4) The CSA fluctuations and their autocorrelation and cross correlation functions due to bond‐length and bond‐angle distortions are predicted for a chemistry Harvard molecular mechanics (CHARMM) molecular dynamics trajectory of Ca2+‐saturated calmodulin and GB3 from the hypersurfaces, as well as for a molecular dynamics (MD) simulation of an NMA trimer using a quantum mechanically correct forcefield. We find that the fluctuations can be represented by a 0.93 scaling factor of the CSA tensor for both R1 and R2 relaxations for residues in helix, coil, and sheet alike. This result is important, as it establishes that 13C′ relaxation is a valid tool for measurement of interesting dynamical events in proteins.
Comparison of the Photophysical Parameters for Three Perylene Bisimide Derivatives by Single‐Molecule Spectroscopy
Authors: Lang Erwin , Hildner Richard , Engelke Hanna , Osswald Peter , Würthner Frank , Köhler Jürgen 
Published: May 2007

AbstractCharacterization of the photophysical parameters for three perylene bisimide derivatives is presented. We exploited time‐resolved and steady‐state spectroscopy on both ensembles and single molecules under ambient as well as cryogenic (1.4 K) conditions. The finding is that these chromophores show extraordinary high fluorescence‐emission rates, low intersystem crossing yields to the triplet state, and relatively short triplet lifetimes.
Relations between different types of jealousy and self and partner perceptions of relationship quality
Authors: Barelds D. P. H. , Barelds‐Dijkstra P. 
Published: May 2007

AbstractThe present paper examines the relationships between relationship quality and three different types of jealousy, including both partners' levels of jealousy and perceptions of relationship quality. It was expected that jealousy in response to a direct threat to the relationship—that is, reactive jealousy—would be positively related to relationship quality, whereas forms of jealousy that may also be triggered in the absence of such a threat would be negatively related to relationship quality. Three studies were conducted among large community samples of heterosexual married and cohabiting couples (a total of 961 couples), using three different operationalizations of relationship quality. In all three studies both partners' levels of reactive jealousy related positively to relationship quality, whereas in all three studies, both partners' levels of anxious jealousy were negatively related to relationship quality. Findings and clinical implications are discussed. Copyright © 2007 John Wiley & Sons, Ltd.