bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytosolic calcium changes in endothelial cells induced by a protein product of human gliomas containing vascular permeability factor activity
Authors: Criscuolo Gregory R. , Lelkes Peter I. , Rotrosen Daniel , Oldfield Edward H.
Published: May 2009

✓ A vascular permeability factor (VPF) derived from serum-free conditioned medium of cultured human malignant gliomas (HG-VPF) has been described previously. The rapid kinetics of HG-VPF activity in an in vivo assay of vascular permeability suggests a direct action upon the vascular endothelial cell. To determine whether HG-VPF was capable of inducing a physiologically significant alteration in isolated endothelial cells, cytosolic calcium [Ca++]i was measured in vitro in these cells before and after their exposure to media containing this substance. This was accomplished by preloading cultured endothelial cells with a fluorescent intracellular Ca++ probe fura-2/AM.

It was found that HG-VPF induced a rapid and transient elevation of [Ca++]i in normal endothelial cells derived from human umbilical vein, bovine adrenal medulla, bovine pulmonary artery, and rat brain. This effect was inhibited by chelating extracellular calcium [Ca++]e with ethyleneglycol-bis (β-aminoethylether)-N,N″ -tetra-acetic acid (EGTA), indicating that the HG-VPF-induced response resulted from the influx of extracellular calcium. The addition of cations that act as nonspecific calcium channel blockers (Li+, Co++, Mn++, La+++) completely inhibited VPF activity, further supporting the role of [Ca++]e influx. The HG-VPF activity was not, however, blocked by verapamil, a calcium antagonist that appears to be specific for voltage-gated calcium channels. Furthermore, exposure of endothelial cells to 120 mM [K+]e did not result in a calcium transient. Coincubation of endothelial cells with dexamethasone inhibited HG-VPF-induced rises in [Ca++]i, while having no effect upon cyclic nucleotide-induced changes in calcium.

The present studies indicate that vascular extravasation induced by human glioma-derived VPF may be mediated by a direct action upon vascular endothelial cells. Furthermore, the observed dexamethasone-induced inhibition of this process suggests a specific cellular action for corticosteroids. This, together with previous observations that dexamethasone suppresses both the production of VPF by tumor cells in vitro and its permeability-inducing activity in vivo, may explain the efficacy of glucocorticoids in the treatment of neoplastic vasogenic brain edema.

Finally, studies with a polycationic peptide (protamine) known to induce blood-brain barrier disruption in vivo revealed similar effects upon endothelial cytosolic calcium levels. As HG-VPF is a positively charged macromolecule, a common interaction between these substances and the negatively charged endothelial cell surface in the induction of permeability is suggested. Nonspecific cross-linking of charged groups of the endothelial glycocalyx and specific HG-VPF receptor binding are both valid mechanisms of HG-VPF-mediated calcium changes. Their potential relevance in the setting of microvascular permeability is discussed.
Monoclonal antibodies with cytotoxic reactivities against human gliomas
Authors: Nanda Anil , Liwnicz Boleslaw , Atkinson Barbara F. , Sela Ben-Ami , Takahashi Hiroshi , Belser Paul H. , Black Perry , Koprowski Hilary , Herlyn Dorothee
Published: May 2009

✓ Monoclonal antibodies (MAb's) reactive with human malignant glioma cells were derived from mice inoculated with cells from fresh glioma tissue. Seven MAb's were selected for study based on their high-level binding in immunoperoxidase and immunofluorescence assay to most of the glioma tissues derived from various patients and based on the absence of binding to normal bone marrow cells. Four of the seven MAb's did not bind to any of the four normal brain tissues tested, whereas three MAb's bound to one or two of these tissues. Two MAb's bound to the surfaces of cultured glioma cells in radioimmunoassay. One of these MAb's (AS-AY1, immunoglobulin (Ig)G1) lysed cultured glioma cells with human lymphocytes or murine macrophages as effector cells; the other MAb (AS-AY2, IgM) was reactive in complement-dependent cytotoxicity assay. These two MAb's therefore seem especially promising reagents in approaches to immunotherapy of human malignant glioma.
Effects of nicardipine on the ex vivo release of eicosanoids after experimental subarachnoid hemorrhage
Authors: Rodriguez y Baena Riccardo , Gaetani Paolo , Marzatico Fulvio , Benzi Gianni , Pacchiarini Lucia , Paoletti Pietro
Published: May 2009

✓ The activation of lipid peroxidation and the enhancement of arachidonic acid metabolism have been demonstrated as indicators of brain damage after subarachnoid hemorrhage (SAH). Meanwhile, the final common pathway of neuronal damage seems to be related to the impaired homeostasis of Ca++. The present study evaluated the effect of the calcium-antagonist nicardipine on arachidonate metabolism after experimental induction of SAH. The ex vivo release of four eicosanoids (prostaglandin (PG)D2, PGE2, 6-keto-PGF1α, and leukotriene (LT)C4) was measured at different intervals after SAH induction. Rats were separated into the following three groups: a sham-operated group, an SAH group (rats were injected with 0.3 ml autologous arterial blood), and an SAH-treated group (after SAH induction, rats were treated with nicardipine 1.2 mg/kg intraperitoneally). Nicardipine significantly decreased the ex vivo release of PGD2 at 48 hours after SAH (p < 0.01). The release of PGE2 was significantly enhanced at 6 hours after SAH, while in the nicardipine-treated group PGE2 release is significantly reduced. Nicardipine also affects the lipoxygenase pathway, reducing the release of LTC4 at 1, 6, and 48 hours after SAH induction. The results of the present study show that nicardipine treatment exerts an inhibitory effect on both biochemical pathways of arachidonic acid metabolism; aside from vascular effects, nicardipine could exert a protective role against the release of arachidonate metabolites, which could play a significant role in the pathogenesis of brain damage after SAH.
Pharmacological studies on relaxation of spastic primate cerebral arteries in subarachnoid hemorrhage
Authors: Kanamaru Kenji , Weir Bryce K. A. , Findlay J. Max , Krueger Christel A. , Cook David A.
Published: May 2009

✓ Chronic cerebral vasospasm was induced in 16 monkeys by direct placement of a clot of autologous blood over the arteries of the circle of Willis on the right side. The middle cerebral arteries (MCA's) on the clot side all showed angiographic vasospasm, which was maximal 7 days after subarachnoid hemorrhage. Animals were sacrificed at this time and vascular responses to acetylcholine (ACh), histamine, and the calcium ionophore A23187 were studied in MCA rings from the clot (spastic) side and the non-clot (control) side. In control preparations with an intact endothelium, which had been precontracted by prostaglandin F2agr; (PGF2agr;), histamine and A23187 produced significant relaxation. The same concentrations of histamine and A23187 did not relax vascular tissues in which the endothelium had been mechanically removed. Acetylcholine did not produce a significant endothelium-dependent relaxation of primate MCA rings, but did relax rings of primate common carotid artery. Pretreatment with chlorpheniramine (an H1-receptor antagonist) prevented histamine-induced relaxation; however, cimetidine (an H2-receptor antagonist) had no inhibitory action. It thus seems that histamine mediates relaxation of intact MCA's mostly by an H1-receptor-mediated release of endothelium-derived relaxing factor (EDRF). Relaxations induced by histamine and A23187 in MCA's from the clot side were substantially reduced. Moreover, the small component of ACh-induced relaxation was also abolished. Endothelium-independent relaxation induced by glyceryl trinitrate (GTN) occurred in arteries from both the control and the clot sides. Constrictions induced by KCl and PGF2agr; were reduced on the clot side of the MCA's. These results suggest that subarachnoid hemorrhage influences both the generation of EDRF and the constriction of affected arteries. The small contraction which was elicited in spastic arteries was fully relaxed by GTN.
Cavernous angioma of the tentorium cerebelli
Authors: Quattrocchi Keith B. , Kissel Phillip , Ellis William G. , Frank Edmund H.
Published: May 2009

✓ The case of a cavernous angioma of the tentorium cerebelli is described. This is the seventh reported case of a cavernous angioma in this unusual location and the first of a dural cavernous angioma demonstrated by magnetic resonance imaging. The clinical presentation, radiographic features, and surgical treatment of these rare tumors are discussed, along with a review of the literature.
Determining the Best Sensing Coverage for 2-Dimensional Acoustic Target Tracking
Authors: Pashazadeh Saeid , Sharifi Mohsen
Published: May 2009

Distributed acoustic target tracking is an important application area of wireless sensor networks. In this paper we use algebraic geometry to formally model 2-dimensional acoustic target tracking and then prove its best degree of required sensing coverage. We present the necessary conditions for three sensing coverage to accurately compute the spatio-temporal information of a target object. Simulations show that 3-coverage accurately locates a target object only in 53% of cases. Using 4-coverage, we present two different methods that yield correct answers in almost all cases and have time and memory usage complexity of Θ(1). Analytic 4-coverage tracking is our first proposed method that solves a simultaneous equation system using the sensing information of four sensor nodes. Redundant answer fusion is our second proposed method that solves at least two sets of simultaneous equations of target tracking using the sensing information of two different sets of three sensor nodes, and fusing the results using a new customized formal majority voter. We prove that 4-coverage guarantees accurate 2-dimensional acoustic target tracking under ideal conditions.
A Butyl Methacrylate Monolithic Column Prepared In-Situ on a Microfluidic Chip and its Applications
Authors: Xu Yi , Zhang Wenpin , Zeng Ping , Cao Qiang
Published: May 2009

A butyl methacrylate (BMA) monolithic column was polymerized in-situ with UV irradiation in an ultraviolet transparent PDMS micro-channel on a homemade micro-fluidic chip. Under the optimized conditions and using a typical polymerization mixture consisting of 75% porogenic solvents and 25% monomers, the BMA monolithic column was obtained as expected. The BET surface area ratio of the BMA monolithic column was 366 m2·g-1. The corresponding SEM images showed that the monolithic column material polymerized in a glass channel was composed of uniform pores and spherical particles with diameters ranging from 3 to 5 μm. The promethazine–luminal–potassium ferricyanide chemiluminescence system was selected for testing the capability of the column. A flow injection analytical technique–chemiluminescence (FIA–CL) system on the microfluidic chip with a BMA monolithic column pretreatment unit was established to determine promethazine. Trace promethazine was enriched by the BMA monolithic column, with more than a 10-fold average enrichment ratio. The proposed method has a linear response concentration range of 1.0×10-8 - 1.0×10-6g·mL-1 and the detection limit was 1.6×10-9g·mL-1.
Wheat Proteins Enhance Stability and Function of Adhesion Molecules in Cryopreserved Hepatocytes
Authors: Grondin Mélanie , Hamel Francine , Averill-Bates Diana A. , Sarhan Fathey
Published: May 2009

Cryopreserved hepatocytes with good hepatospecific functions upon thawing are important for clinical transplantation and for in vitro drug toxicity testing. However, cryopreservation reduces viability and certain hepatospecific functions, but the most pronounced change is diminished attachment efficiency of hepatocytes. Adhesion of cells to the extracellular matrix and cell–cell contacts are crucial for many aspects of cellular function. These processes are partly mediated and controlled by cellular adhesion molecules. The mechanisms responsible for reduced attachment efficiency of cryopreserved hepatocytes are not well understood. To address this question, we investigated the effect of a new cryopreservation procedure, using wheat proteins (WPs) or mixtures of recombinant forms of wheat freezing tolerance-associated proteins, on the stability of three important adhesion molecules (β1-integrin, E-cadherin, and β-catenin). Immunoblot analyses revealed that the levels of β1-integrin, E-cadherin, and β-catenin were much lower in cryopreserved rat hepatocytes, when compared to fresh cells. Protein expression of the adhesion molecules was generally lower in cells cryopreserved with DMSO, compared to WPs. Moreover, the stability of the adhesion molecules was not affected by cryopreservation to the same degree, with more pronounced decreases occurring for β1-integrin (62–74%) > β-catenin (51–58%) > E-cadherin (21–37%). However, when hepatocytes were cryopreserved with partially purified WPs (SulWPE, AcWPE) or with mixtures of recombinant wheat proteins, there was a clear protective effect against the loss of protein expression of β1-integrin, E-cadherin, and β-catenin. Protein expression was only 10–20% lower than that observed in fresh hepatocytes. These findings clearly demonstrate that WPs, and more particularly, partially purified WPs and recombinant wheat proteins, were more efficient for cryopreservation of rat hepatocytes by maintaining good expression of these adhesion molecules. These promising results could lead to a new and improved cryopreservation technology for applications such as clinical transplantation of hepatocytes.
Cotransplantation of Mouse Embryonic Stem Cells and Bone Marrow Stromal Cells following Spinal Cord Injury Suppresses Tumor Development
Authors: Matsuda Ryosuke , Yoshikawa Masahide , Kimura Hajime , Ouji Yukiteru , Nakase Hiroyuki , Nishimura Fumihiko , Nonaka Jun-Ichi , Toriumi Hayato , Yamada Shuichi , Nishiofuku Mariko , Moriya Kei , Ishizaka Shigeaki , Nakamura Mitsutoshi , Sakaki Toshisuke
Published: May 2009

Embryonic stem (ES) cells are a potential source for treatment of spinal cord injury (SCI). Although one of the main problems of ES cell-based cell therapy is tumor formation, there is no ideal method to suppress tumor development. In this study, we examined whether transplantation with bone marrow stromal cells (BMSCs) prevented tumor formation in SCI model mice that received ES cell-derived grafts containing both undifferentiated ES cells and neural stem cells. Embryoid bodies (EBs) formed in 4-day hanging drop cultures were treated with retinoic acid (RA) at a low concentration of 5 × 10–9 M for 4 days, in order to allow some of the ES cells to remain in an undifferentiated state. RA-treated EBs were enzymatically digested into single cells and used as ES cell-derived graft cells. Mice transplanted with ES cell-derived graft cells alone developed tumors at the grafted site and behavioral improvement ceased after day 21. In contrast, no tumor development was observed in mice cotransplanted with BMSCs, which also showed sustained behavioral improvement. In vitro results demonstrated the disappearance of SSEA-1 expression in cytochemical examinations, as well as attenuated mRNA expressions of the undifferentiated markers Oct3/4, Utf1, Nanog, Sox2, and ERas by RT-PCR in RA-treated EBs cocultured with BMSCs. In addition, MAP2-immunopositive cells appeared in the EBs cocultured with BMSCs. Furthermore, the synthesis of NGF, GDNF, and BDNF was confirmed in cultured BMSCs, while immunohistochemical examinations demonstrated the survival of BMSCs and their maintained ability of neurotrophic factor production at the grafted site for up to 5 weeks after transplantation. These results suggest that BMSCs induce undifferentiated ES cells to differentiate into a neuronal lineage by neurotrophic factor production, resulting in suppression of tumor formation. Cotransplantation of BMSCs with ES cell-derived graft cells may be useful for preventing the development of ES cell-derived tumors.
Beneficial Role of Pancreatic Microenvironment for Angiogenesis in Transplanted Pancreatic Islets
Authors: Lau Joey , Kampf Caroline , Mattsson Göran , Nyqvist Daniel , Köhler Martin , Berggren Per-Olof , Carlsson Per-Ola
Published: May 2009

Pancreatic islets implanted heterotopically (i.e., into the kidney, spleen, or liver) become poorly revascularized following transplantation. We hypothesized that islets implanted into the pancreas would become better revascularized. Islets isolated from transgenic mice expressing enhanced yellow fluorescent protein (EYFP) in all somatic cells were cultured before they were implanted into the pancreas or beneath the renal capsule of athymic mice. Vascular density was evaluated in histological sections 1 month posttransplantation. EYFP was used as reporter for the transgene to identify the transplanted islets. Islet endothelial cells were visualized by staining with the lectin Bandeiraea simplicifolia (BS-1). Capillary numbers in intrapancreatically implanted islets were only slightly lower than those counted in endogenous islets, whereas islets implanted beneath the renal capsule had a markedly lower vascular density. In order to determine if this high graft vascular density at the intrapancreatic site reflected expansion of remnant donor endothelial cells or increased ingrowth of blood vessels from the host, also islets from Tie2-green fluorescent protein (GFP) mice (i.e., islets with fluorescent endothelial cells) were transplanted into the pancreas or beneath the renal capsule of athymic mice. These islet grafts revealed that the new vascular structures formed in the islet grafts contained very few GFP-positive cells, and thus mainly were of recipient origin. The reason(s) for the much better ingrowth of blood vessels at the intrapancreatic site merits further studies, because this may help us form strategies to overcome the barrier for ingrowth of host vessels also into islets in heterotopic implantation sites.
Retentive Multipotency of Adult Dorsal Root Ganglia Stem Cells
Authors: Singh Rabindra P. , Cheng Ying-Hua , Nelson Paul , Zhou Feng C.
Published: May 2009

Preservation of neural stem cells (NSCs) in the adult peripheral nervous system (PNS) has recently been confirmed. However, it is not clear whether peripheral NSCs possess predestined, bona fide phenotypes or a response to innate developmental cues. In this study, we first demonstrated the longevity, multipotency, and high fidelity of sensory features of postmigrating adult dorsal root ganglia (aDRG) stem cells. Derived from aDRG and after 4–5 years in culture without dissociating, the aDRG NSCs were found capable of proliferation, expressing neuroepithelial, neuronal, and glial markers. Remarkably, these aDRG NSCs expressed sensory neuronal markers vesicular glutamate transporter2 (VGluT2—glutamate terminals), transient receptor potential vanilloid1 (TrpV1—capsaicin sensitive), phosphorylated 200 kDa neurofilaments (pNF200—capsaicin insensitive, myelinated), and the serotonin transporter (5-HTT), which normally is transiently expressed in developing DRG. Furthermore, in response to neurotrophins, the aDRG NSCs enhanced TrpV1 expression upon exposure to nerve growth factor (NGF), but not to brain-derived neurotrophic factor (BDNF). On the contrary, BDNF increased the expression of NeuN. Third, the characterization of aDRG NSCs was demonstrated by transplantation of red fluorescent-expressing aDRG NSCs into injured spinal cord. These cells expressed nestin, Hu, and β-III-tubulin (immature neuronal markers), GFAP (astrocyte marker) as well as sensory neural marker TrpV1 (capsaicin sensitive) and pNF200 (mature, capsaicin insensitive, myelinated). Our results demonstrated that the postmigrating neural crest adult DRG stem cells not only preserved their multipotency but also were retentive in sensory potency despite the age and long-term ex vivo status.
Noninvasive Imaging of Liver Repopulation following Hepatocyte Transplantation
Authors: Koenig Sarah , Krause Petra , Hosseini Ali Seif Amir , Dullin Christian , Rave-Fraenk Margret , Kimmina Sarah , Entwistle Andrew Lee , Hermann Robert Michael , Hess Clemens Friedrich , Becker Heinz , Christiansen Hans
Published: May 2009

Near infrared fluorescence (NIRF) optical imaging is a technique particularly powerful when studying in vivo processes at the molecular level in preclinical animal models. We recently demonstrated liver irradiation under the additional stimulus of partial hepatectomy as being an effective primer in the rat liver repopulation model based on hepatocyte transplantation. The purpose of this study was to assess optical imaging and the feasibility of donor cell expansion tracking in vivo using a fluorescent probe. Livers of dipeptidylpeptidase IV (DPPIV)-deficient rats were preconditioned with irradiation. Four days later, a partial hepatectomy was performed and wild-type (DPPIV+) hepatocytes were transplanted into recipient livers via the spleen. Repopulation by transplanted DPPIV+ hepatocytes was detected in vivo with Cy5.5-conjugated DPPIV antibody using the eXplore Optix™ System (GE HealthCare). Results were compared with nontransplanted control animals and transplanted animals receiving nonspecific antibody. Optical imaging detected Cy5.5-specific fluorescence in the liver region of the transplanted animals, increasing in intensity with time, representing extensive host liver repopulation within 16 weeks following transplantation. A general pattern of donor cell multiplication emerged, with an initially accelerating growth curve and later plateau phase. In contrast, no specific fluorescence was detected in the control groups. Comparison with ex vivo immunofluorescence staining of liver sections confirmed the optical imaging results. Optical imaging constitutes a potent method of assessing the longitudinal kinetics of liver repopulation in the rat transplantation model. Our results provide a basis for the future development of clinical protocols for suitable fluorescent dyes and imaging technologies.
DNA barcoding will frequently fail in complicated groups: An example in wild potatoes
Authors: Spooner David M.
Published: May 2009

DNA barcoding (“barcoding”) has been proposed as a rapid and practical molecular method to identify species via diagnostic variation in short orthologous DNA sequences from one or a few universal genomic regions. It seeks to address in a rapid and simple way the “taxonomic impediment” of a greater need for taxonomic identifications than can be supplied by taxonomists. Using a complicated plant group,Solanumsect.Petota(wild potatoes), I tested barcoding with the most variable and frequently suggested plant barcoding regions: the internal nontranscribed spacer of nuclear ribosomal DNA (ITS) and the plastid markerstrnH‐psbAintergenic spacer andmatK. These DNA regions fail to provide species‐specific markers in sect.Petotabecause the ITS has too much intraspecific variation and the plastid markers lack sufficient polymorphism. The complications seen in wild potatoes are common in many plant groups, but they have not been assessed with barcoding. Barcoding is a retroactive procedure that relies on well‐defined species to function, is based solely on a limited number of DNA sequences that are often inappropriate at the species level, has been poorly tested with geographically well‐dispersed replicate samples from difficult taxonomic groups, and discounts substantial practical and theoretical problems in defining species.
Development and morphology of flowers and inflorescences in Balanophora papuana and B. elongata (Balanophoraceae)
Authors: Eberwein Roland , Nickrent Daniel L. , Weber Anton
Published: May 2009

Extreme modification and reduction in floral morphology presents an obstacle to determining the evolutionary relationships and homologies of the holoparasites in Balanophoraceae. Developing flowers and inflorescences of two dioecious species, Balanophora papuana and B. elongata, were compared to each other and to the monoecious B. fungosa. Intermingled with flowers in the male inflorescences are bracts (B. elongata) or bract parts (B. papuana). In the latter, early cessation of bract tip growth results in two half‐bracts, which become displaced during inflorescence elongation, thus disproving the view that these bract‐like structures are axial in nature. Male flower primordia emerge in positions axillary to the dividing bracts, and both arise in a spiral sequence. This pattern is modified in B. papuana by the formation of pseudowhorls of four. In both species, the staminate flowers consist of a generally four‐merous perianth and a synandrium of congenitally fused stamens. Male flower and bract ontogeny (but not pollen sacs) conform to patterns seen in other angiosperms. More problematic are the carpellate flowers whose primordia arise in irregular order between club‐shaped, radially symmetrical organs called claviform bodies. The interpretation that these bodies are homologous to the peltate bracts of Helosideae appears plausible, but cannot explain their nonspiral initiation and radial symmetry.
Polyionic polymers – heterogeneous media for metal nanoparticles as catalyst in Suzuki–Miyaura and Heck–Mizoroki reactions under flow conditions
Authors: Mennecke Klaas , Kirschning Andreas
Published: May 2009

The preparation of monolithic polyionic supports which serve as efficient heterogeneous supports for palladium(0) nanoparticles is described. These functionalized polymers were incorporated inside a flow reactor and employed in Suzuki–Miyaura and Heck cross couplings under continuous flow conditions.
NEW RULE FOR CHOICE OF THE REGULARIZATION PARAMETER IN (ITERATED) TIKHONOV METHOD
Authors: Raus Toomas , Hämarik Uno
Published: May 2009

We propose a new a posteriori rule for choosing the regularization parameter α in (iterated) Tikhonov method for solving linear ill‐posed problems in Hilbert spaces. We assume that data are noisy but noise level δ is given. We prove that (iterated) Tikhonov approximation with proposed choice of α converges to the solution as δ → 0 and has order optimal error estimates. Under certain mild assumption the quasioptimality of proposed rule is also proved. Numerical examples show the advantage of the new rule over the monotone error rule, especially in case of rough δ.
APPLICATION OF FRACTIONAL SENSOR FUSION ALGORITHMS FOR INERTIAL MEMS SENSING
Authors: Romanovas Michailas , Klingbeil Lasse , Traechtler Martin , Manoli Yiannos
Published: May 2009

The work presents an extension of the conventional Kalman filtering concept for systems of fractional order (FOS). Modifications are introduced using the Grünwald‐Letnikov (GL) definition of the fractional derivative (FD) and corresponding truncation of the history length. Two versions of the fractional Kalman filter (FKF) are shown, where the FD is calculated directly or by augmenting the state vector with the estimate of the FD. The filters are compared to conventional integer order (IO) Position (P‐KF) and Position‐Velocity (PV‐KF) Kalman filters as well as to an adaptive Interacting Multiple‐Model Kalman Filter (IMM‐KF). The performance of the filters is assessed based on a hand and a head motion data set. The feasibility of the given approach is shown.
Use of wild and cultivated foods by chimpanzees at Bossou, Republic of Guinea: feeding dynamics in a human‐influenced environment
Authors: Hockings Kimberley J. , Anderson James R. , Matsuzawa Tetsuro
Published: May 2009

Increased human population growth and more conversions of natural habitat to agricultural land have resulted in greater proximity between humans and nonhuman primate species. Consequent increases in resource competition including crop‐raiding are a by‐product of both natural resources becoming less available and the nutritional benefits of cultivated foods becoming more known to the nonhuman primates. Chimpanzees at Bossou in the Republic of Guinea, West Africa, consume 17 different types of cultivated foods that are grown extensively throughout their small, fragmented home range. Direct observations of feeding behavior conducted over an 18‐month period revealed that during specific months crops account for up to one quarter of chimpanzee feeding time, with higher overall crop‐raiding levels throughout the periods of wild fruit scarcity. Some cultivated foods, especially sugar fruits, are mostly fallback foods, whereas others, such as rice pith (Oryza sp.) and maize (Zea mays), are consumed according to their availability even when wild foods are abundant. These findings highlight the importance of both crop choice by farmers and a thorough understanding of the ecology of resident primate species when establishing land management techniques for alleviating human–primate conflict. Am. J. Primatol. 71:636–646, 2009. © 2009 Wiley‐Liss, Inc.
Ist die Enantioselektivität bei der asymmetrischen Katalyse vorhersagbar?
Authors: Brown John M. , Deeth Robert J.
Published: May 2009

Vorheersagekraft: Um berechnete ee‐Werte mit experimentellen ee‐Werten zur Deckung zu bringen, wurde eine Reihe von Rechenmethoden eingesetzt. Neue Verfahren, bei denen quantenmechanische und molekülmechanische Methoden kombiniert werden, sind sehr erfolgreich.

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Allylische Aminierung durch einen DNA‐Dien‐Iridium(I)‐ Hybridkatalysator
Authors: Fournier Pierre , Fiammengo Roberto , Jäschke Andres
Published: May 2009

DNA‐Hybridkatalyse trifft Organometallchemie: Ein DNA‐Strang, der mit Dien‐Liganden funktionalisiert wurde, bildet Iridium(I)‐Komplexe, die eine allylische Aminierung im wässrigen Medium effektiv zu katalysieren vermögen (siehe Schema). Die DNA‐basierten Komplexe zeigen hohe Stabilität und Aktivität, außerdem beeinflusst ihre Sekundärstruktur die Stereoselektivität der Reaktion.

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Surprisingly Long‐Range Surface‐Enhanced Raman Scattering (SERS) on Au–Ni Multisegmented Nanowires
Authors: Wei Wei , Li Shuzhou , Millstone Jill E. , Banholzer Matthew J. , Chen Xiaodong , Xu Xiaoyang , Schatz George C. , Mirkin Chad A.
Published: May 2009

Very long range surface‐enhanced Raman scattering is observed from a nickel nanowire that is separated by 120 nm from a pair of gold nanodisks. The excitation of the surface‐plasmon resonance (SPR) from the gold nanodisk pair generates an enhanced electromagnetic field near the nickel segment (SEM, left), leading to Raman intensity greater than the nickel alone (right).

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Pretubulysin, a Potent and Chemically Accessible Tubulysin Precursor from Angiococcus disciformis
Authors: Ullrich Angelika , Chai Yi , Pistorius Dominik , Elnakady Yasser A. , Herrmann Jennifer E. , Weissman Kira J. , Kazmaier Uli , Müller Rolf
Published: May 2009

Simplify, simplify, simplify! Pretubulysin (structure without the green substituents), a simplified tubulysin was prepared in the laboratory and also found in a natural myxobacterial source. This biosynthetic precursor of the tubulysins is not as active as tubulysins A and D but is still effective in picomolar concentrations against cancer cell lines.

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Allylic Amination by a DNA–Diene–Iridium(I) Hybrid Catalyst
Authors: Fournier Pierre , Fiammengo Roberto , Jäschke Andres
Published: May 2009

DNA hybrid catalysis goes organometallic: A DNA strand functionalized with diene ligands forms iridium(I) complexes that can efficiently catalyze an allylic amination in aqueous medium (see scheme). The DNA‐based complexes show high stability and activity, and their secondary structure influences the stereoselectivity of the reaction.

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An Odd‐Electron Complex [Ruk(NOm)(Qn)(terpy)]2+ with Two Prototypical Non‐Innocent Ligands
Authors: Das Atanu Kumar , Sarkar Biprajit , Duboc Carole , Strobel Sabine , Fiedler Jan , Záliš Stanislav , Lahiri Goutam Kumar , Kaim Wolfgang
Published: May 2009

Six combinations of oxidation states are conceivable for the paramagnetic title complex. Single‐crystal X‐ray diffraction, spectroscopic analysis (IR, EPR at conventional and high frequency), and DFT calculations establish that it is the iminosemiquinone radical structure that is formed: [Ruk(NOm)(Qn)(terpy)]2+ (k=2+, m=1+, n=1−).

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Functionalized Templates for the Convergent Assembly of Polyethers: Synthesis of the HIJK Rings of Gymnocin A
Authors: Van Dyke Aaron R. , Jamison Timothy F.
Published: May 2009

Extension ladder: The successful application of epoxide‐opening strategies towards the synthesis of ladder‐type polyethers is contingent upon further elaboration of the product. By employing two different functionalized templates, a fragment of gymnocin A that bears four sites for subsequent fragment coupling has been prepared (see scheme; Bn=benzyl).

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Prediction of water retention capacity of hydrolysed electrospun polyacrylonitrile fibers using statistical model and artificial neural network
Authors: Giri Dev Venkateshwarapuram Rengaswami , Venugopal Jayarama Reddy , Senthilkumar Muthusamy , Gupta Deepika , Ramakrishna Seeram
Published: May 2009

Box Behnken design of experiment was used to study the effect of process variables such as alkali concentration, temperature and time on water retention capacity of the alkaline hydrolysed electrospun fibres. The hydrolysis of electrospun polyacrylonitrile fibres was carried out using sodium hydroxide with different processing conditions like concentration of alkali, temperature and time. With the increase in the concentration of alkali, time and temperature, the water retention capacity of membrane was found to increase in the membranes. Water retention capacities of the membranes were modeled and predicted using empirical as well as artificial neural network (ANN model). The fiber diameter and mean flow pore diameter of electrospun polyacrylonitrile fibers and hydrolyzed fibers shown in SEM images were 310 ± 50, 275 ± 75 nm, 0.9258 and 1.12 microns, respectively. The present study indicated that the nanofibrous membranes have potential for the water absorbing applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Swelling properties of CMC‐g‐poly (AAm‐co‐AMPS) superabsorbent hydrogel
Authors: Pourjavadi Ali , Ghasemzadeh Hossein , Mojahedi Fatemeh
Published: May 2009

A series of biopolymer‐based superabsorbent hydrogels based on carboxymethyl cellulose has been prepared by free‐radical graft copolymerization of acrylamide and 2‐acrylamido‐2‐methylpropan sulfonic acid (AMPS) in aqueous solution using methylenebisacrylamide as a crosslinking agent and ammonium persulfate as an initiator. The effect of variables on the swelling capacity such as: acrylamide/AMPS weight ratio, reaction temperature, and concentration of the initiator and crosslinker were systematically optimized. The results indicated that with increasing the amount of AMPS, the swelling capacity is increased. FT‐IR spectroscopy and scanning electron microscope analysis were used to confirm the hydrogel structure. Swelling measurements of the synthesized hydrogels in different salt solutions indicated considerable swelling capacity. The absorbency under load of the superabsorbent hydrogels was determined by using an absorbency under load tester at various applied pressures. A preliminary swelling and deswelling behaviors of the hydrogels were also studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of PEG‐functionalized poly(diphenylacetylene)s and their gas permeation properties
Authors: Sakaguchi Toshikazu , Kameoka Koji , Hashimoto Tamotsu
Published: May 2009

The polymerizations of 1‐(3‐methylphenyl)‐2‐(4‐trimethylsilyl)phenylacetylene (1a) and 1‐(4‐methylphenyl)‐2‐(4‐trimethylsilyl)phenylacetylene (1b) were carried out with TaCl5‐n‐Bu4Sn to give relatively high‐molecular‐weight polymers (2a and 2b) (Mn > 5 × 105). The obtained polymers were brominated by using benzoyl peroxide and N‐bromosuccinimide first, followed by substitution reaction of three types of polyethylene glycol. When diethylene glycol was used as a reagent on substitution reaction of meta‐substituted polymer, PEG‐functionalized poly(diphenylacetylene) with the highest content of oxyethylene unit [4a(2)] was obtained, and the degree of substitution was 0.60. The degrees of substitution decreased to 0.15 and 0.08 when the polyethylene glycols with higher molecular weights were used. PEG‐substitution reaction to the para‐substituted polymers was difficult to proceed, and hence the degree of substitution was 0.18 even when diethylene glycol was used. The CO2/N2 separation factor of PEG‐functionalized polymer [4a(2)] was as large as 28.8, although that of 2a was 7.41. The other PEG‐functionalized polymers also exhibited high CO2 permselectivity, and their CO2/N2 separation factors were over 20. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Modeling the PAAc‐AN‐TV surface using 134Cs and 152+154Eu sorption
Authors: El‐Gammal Bela , Ibrahim Gehan M. , Allan Karam F. , El‐Naggar Ibrahim M.
Published: May 2009

A novel composite, composed of poly (acrylic acid (AAc), acrylonitrile, and titanium vanadate, was prepared by induced gamma irradiation route at 20 kGy to be used as a hybrid organic‐inorganic sorbent. 5–200 μm particle diameters of the composite were obtained. An average particle size of 75 μm of crystalline (17‐20) composite was used; it was thermally stable to 486°C. The distribution coefficients of Cs+ and Eu3+ were studied as a function of pH; 2350 mL·g−1 and 645 mL·g−1 were obtained in case of 152+154Eu and 134Cs at pH 6. 1.55 mmol·g−1 and 1.85 mmol·g−1 maximum loadings were accommodated for the same ions at the same pH. Different models were used to scan the surface of the exchanger, so that the topography of the surface was studied as a function of surface active site types, concentrations, and heterogeneity. Langmuir, Freundlich and D‐R models were used. Also, different kinetic models, as Lagergren pseudo first‐order, pseudo second‐order and Morris‐Weber intraparticle diffusion models were applied to study the possible mechanism of the sorption process; pseudo first‐order was exempted to investigate the mechanism. They proved that chemisorption and ion exchange mechanism with controlled diffusion are predominant, with their characteristic mean energies (8.731 kJ·mol−1 and 9.310 kJ·mol−1 for Cs+ and Eu3+, respectively). Double Shell Model was finally adopted to explain the suggested mechanism. Negative values of ΔG°, −2.15 kJ·mol−1 to −7.92 kJ·mol−1 in case of Cs+ and −3.35 kJ·mol−1 to −9.67 kJ·mol−1 in case of Eu3+adsorption at different temperatures, indicate the spontaneous nature of the reactions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A moisture absorption and adhesion study of the process of blending film using p‐alkylphenol‐resorcinol‐formaldehyde and rubber latex
Authors: Shen Mingxia , Zhang Junsheng , Chen Qingmin
Published: May 2009

p‐alkylphenol‐resorcinol‐formaldehyde‐latex (ARFL) films were prepared by co‐condensation of p‐alkylphenols and resorcinol with formaldehyde to generate modified phenolic resins, followed by blending with rubber latex, aging, and finally curing. The weight‐gain of the ARFL films and the tensile force of the coated fiberglass were studied under different temperatures and various humidities. The surfaces of the ARFL films were further analyzed by measuring the static contact angle and the findings were confirmed by Fourier Transform Infrared Spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS) analysis. The adhesion between the coated fiberglass and neoprene rubber was evaluated using the H‐adhesion technique. The best hydrophobicity and the largest water contact angle were displayed on the surface of the p‐nonylphenol‐resorcinol‐formaldehyde‐latex (NRFL) film, with a weight‐gain percent that was 40.0% (wt %) lower and a static contact angle that was 22.6° more than that of the resorcinol‐formaldehyde‐latex (RFL) film. The NRFL‐coated fiberglass had a higher tensile force and H‐adhesion force than the RFL‐coated fiberglass. The shelf life of NRFL‐coated fiberglass can be raised significantly at 40°C and under 98% humidity. The mechanism of the dramatic drop in the tensile force of the coated fiberglass is also discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Cure kinetics and catalyzed effect of hydroxyl group of LC diglycidyl ether of bisphenol‐S with aromatic diamines
Authors: Huo Li , Gao Jungang , Zhang Xiaona
Published: May 2009

The curing reactions of liquid crystalline 4,4′‐bis‐(2,3‐epoxypropyloxy)‐sulfonyl‐bis(1,4‐phenylene) (p‐BEPSBP) with 4,4′‐diaminodiphenylmethane (DDM) and 4,4′‐diaminodiphenylsulfone (DDS) were investigated by nonisothermal differential scanning calorimeter (DSC). The relationships of Ea with the conversion α in the curing process were determined. The catalyzed activation of hydroxyl group for curing reaction of epoxy resins with amine in DSC experiment was discussed. The results show that these curing reactions can be described by the autocatalytic Šesták‐Berggren model. The curing technical temperature and parameters were obtained, and the even reaction orders m, n, and ΔS for p‐BEPSBP/DDM and p‐BEPSBP/DDS are 0.35, 0.92, −81.94 and 0.13, 1.32, −24.45, respectively. The hydroxyl group has catalyzed activation for the epoxy–amine curing system in the DSC experiment. The average Ea of p‐BEPSBP/DDM is 67.19 kJ mol−1 and is 105.55 kJ mol−1 for the p‐BEPSBP/DDS system, but it is different for the two systems; when benzalcohol as hydroxyl group was added to the curing system, the average Ea of p‐BEPSBP/DDM decreases and increases for p‐BEPSBP/DDS. The crystalline phase had formed in the curing process and was fixed in the system. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The importance of bare marine sedimentary habitats for maintaining high polychaete diversity and the implications for the design of marine protected areas
Authors: Barrio Froján Christopher R. S. , Kendall Mike A. , Paterson Gordon L. J. , Hawkins Lawrence E. , Nimsantijaroen Sompoch , Aryuthaka Chittima
Published: May 2009

Bare intertidal sedimentary habitats have received relatively little attention compared with their neighbouring vegetated habitats. An ecological comparison of benthic faunal assemblages inhabiting tropical intertidal seagrass beds and bare sediments has been made to assess the faunal similarity between the two habitats in south‐east Asia.

The poorly developed taxonomy of most invertebrate taxa in the region precluded the full identification of many faunal groups. Only the polychaetes — which accounted for 76% of all the macrofaunal organisms collected — were identified to the lowest possible taxonomic level, yielding 177 nominal species belonging to 35 families. Ecological analyses suggested that although each habitat had a distinct polychaete assemblage, there were few differences between habitats based on a range of calculated assemblage diversity metrics.

Further analyses were applied to the data to test the performance of three strategies for optimizing the selection of sites for inclusion in potential marine protected areas. Strategies were based either on the total number of species, the number of rare or endemic species, or on the level of species richness (used as a surrogate for community structure).

All three strategies consistently captured above average numbers of species at most levels of conservation intensity. The merits of each strategy are considered in turn.

Copyright © 2009 John Wiley & Sons, Ltd.
Inquiry project‐based learning with a partnership of three types of teachers and the school librarian
Authors: Chu Kai Wah Samuel
Published: May 2009

Using an inquiry project‐based learning (PBL) approach that involved the collaboration of three kinds of teachers (general studies, language, and information technology [IT]) and the librarian, primary 4 students from a Hong Kong school were guided through group projects. The effect of this approach was examined by comparing the project grades of students who took part in the inquiry PBL project with those of a control group. Surveys and interviews were conducted with students (N1= 141), parents (N2= 27), and teachers (N3= 11). The comparison of group project grades revealed significantly higher scores for the inquiry PBL groups (p< 0.05). Surveys showed that students were perceived to have improved in eight dimensions of learning, with no significant differences (p> 0.05) between students, parents, and teachers. Students enjoyed the projects and perceived them to be relatively easy. Gender differences and academic abilities had no significant moderating effects on the learning dimensions. Examination of the approach showed the collaboration between the four teaching staff to be effective through the support of the school administration, an inquiry learning expert, and parents. On the other hand, the main limitation was the extra workload for the teachers. Nevertheless, the study participants and stakeholders all advocate the continued implementation of the approach.
Berechnung der Knicklast in Bogenebene von Netzwerkbögen
Authors: Schanack Frank
Published: May 2009

Netzwerkbögen sind Stabbogenbrücken mit geneigten Hängern, die sich mehrmals kreuzen. In den letzten fünf Jahren wurde eine bedeutende Anzahl von neuen Netzwerkbogenbrücken gebaut und vielleicht eine Abwendung von den traditionellen Stabbögen mit vertikalen Hängern eingeleitet. Wenn neue Tragwerke in die Bautechnik eingeführt werden, ist es wichtig, ihr Tragverhalten zu verstehen, um das gewohnte Sicherheits‐ und Qualitätsniveau zu wahren. In Bögen ist in diesem Zusammenhang das Stabilitätsverhalten von besonderem Interesse. Die einzige existierende Lösung kann das Knicken von Netzwerkbögen in ihrer Ebene nicht in befriedigendem Maße erklären, da ihr Anwendungsbereich auf einen Sonderfall begrenzt ist. Eine allgemeine Parameterstudie des Knickens in Bogenebene führt zu einem Konzept, nach dem das Problem als ein gekrümmter Druckstab mit radialer elastischer Bettung aufgefasst werden kann. Es wird daraufhin eine einfache analytische Formel hergeleitet, die die kritische elastische Knicklast und die kritische Eigenform mit einem Fehler von weniger als 5% voraussagt.

Calculation of the critical in‐plane buckling load of network arches.

Network arches are tied arch bridges with inclined hangers, which have multiple intersections. In the last five years there has been built a significant number of network arch bridges, maybe initiating a turning away from the traditional tied arches with vertical hangers. When introducing new structures it is important to understand well its structural behaviour in order to assure the usual safety and quality level. In arches, the buckling behaviour is of particular interest. The existent solution does not explain the in‐plane buckling of network arches to a satisfying extent, limiting its application range to a special case. A general parametric study of the in‐plane buckling leads to a concept, which allows considering the problem as a curved compression strut with radial elastic support. Then, a simple analytical formula is derived that predicts the critical buckling load and buckling mode for in‐plane buckling of network arch bridges with an error of less than 5%.