bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect on bone growth enhancement of implant coatings with hydroxyapatite and collagen deposited electrochemically and by plasma spray
Authors: Daugaard Henrik , Elmengaard Brian , Bechtold Joan E. , Jensen Thomas , Soballe Kjeld
Published: March 2009

Skeletal bone consists of hydroxyapatite (HA) [Ca10(PO4)6(OH)2] and collagen type I, both of which are osseoconductive. The goal of osseointegration of orthopedic and dental implants is the rapid achievement of a mechanically stable long‐lasting fixation between bone and an implant surface. In this study, we evaluated the mechanical fixation and tissue distribution surrounding implants coated with three surfaces: plasma‐sprayed HA coating, thinner coating of electrochemical‐assisted deposition of HA, and an identical thin coating with a top layer of mineralized collagen. Uncoated plasma‐sprayed titanium (Ti‐6Al‐4V) served as negative control. The electrochemical‐assisted deposition was performed near physiological conditions. We used a canine experimental joint replacement model with four cylindrical implants (one of each treatment group) inserted in the humeri cancellous metaphyseal bone in a 1 mm gap. Observation time was 4 weeks. The mechanical fixation was quantified by push‐out test to failure, and the peri‐implant tissue formation by histomorphometric evaluation. HA coatings deposited by plasma spray technique or electrochemically, increased the mechanical fixation and bone ongrowth, but there was no statistical difference between the individual HA applications. Addition of collagen to the mineralized phase of the coating to create a more bone natural surface did not improve the osseoconductive effect of HA. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Evaluating antimicrobials and implant materials for infection prevention around transcutaneous osseointegrated implants in a rabbit model
Authors: Chou Teri G. Rosenbaum , Petti Cathy A. , Szakacs Juliana , Bloebaum Roy D.
Published: March 2009

Transcutaneous osseointegrated implants can improve function for select amputee patients, but infection serves as a significant limitation of implantable transcutaneous devices. This study examined the efficacy of an antimicrobial, pexiganan acetate (SUPONEX™), and a porous tantalum implant material (Trabecular Metal™) in preventing pin tract infection of osseointegrated implants in a rabbit model. Thirty‐seven rabbits were randomized to three groups: Ti‐control group (n = 11) with titanium alloy implant and no antimicrobial, Ti‐Pexiganan group (n = 8) with titanium alloy implant and topical pexiganan acetate 1% applied daily at the skin/implant interface, and Ta‐control group (n = 18) with porous tantalum implant and no antimicrobial. All implants were placed transcutaneously through skin, muscle, and bone. Rabbits were monitored for infection for 24 weeks. We observed a 75% reduction in rates of pin tract infection in the Ti‐Pexiganan group compared to that observed in the Ti‐control group (p = 0.019). No difference in rates of infection was observed between the Ta‐control group and the Ti‐control group (p = 0.230). In conclusion, pexiganan acetate may be an important antimicrobial for transcutaneous osseointegrated implants. Porous tantalum will not likely prevent pin tract infection without additional methods of soft tissue immobilization around the implant site. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Novel multiarm PEG‐based hydrogels for tissue engineering
Authors: Tan Huaping , DeFail Alicia J. , Rubin J. Peter , Chu Constance R. , Marra Kacey G.
Published: March 2009

Injectable scaffolds are promising substrates for regenerative medicine applications. In this study, multiarm amino‐terminated poly(ethylene glycol) (PEG) hydrogels were crosslinked with genipin, a compound naturally derived from the gardenia fruit. Four‐ and eight‐arm amino‐terminated PEG hydrogels crosslinked with varying concentrations of genipin were characterized. Both surface and cross‐sectional structures of PEG‐based hydrogels were observed by scanning electron microscopy. In vitro gelation time, water uptake, swelling, and weight loss of PEG hydrogels in phosphate buffered saline at 37°C were studied. The results showed that the eight‐arm PEG demonstrated a much slower gelation time compared with the four‐arm PEG, which may be due to the differing structures of the multiarm PEG hydrogels, which in turn affects the ability of genipin to react with the amine groups. Human adipose‐derived stem cells were seeded onto the four‐ and eight‐arm PEG hydrogels in vitro to assess the biological performance and applicability of the gels as cell carriers. The four‐arm PEG hydrogel resulted in enhanced cell adhesion when compared with the eight‐arm PEG hydrogel. Overall, these characteristics provide a potential opportunity for multiarm PEG hydrogels as injectable scaffolds in a variety of tissue engineering applications. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Performance of plane‐wave‐based LDA+U and GGA+U approaches to describe magnetic coupling in molecular systems
Authors: Rivero Pablo , Loschen Christoph , Moreira Ibério De P. R. , Illas Francesc
Published: March 2009

This work explores the performance of periodic plane wave density functional theory calculations with an on‐site Coulomb correction to the standard LDA and GGA exchange‐correlation potential—commonly used to describe strongly correlated solids—in describing the magnetic coupling constant of a series of molecular compounds representative of dinuclear Cu complexes and of organic diradicals. The resulting LDA+U or GGA+U formalisms, lead to results comparable to experiment and to those obtained by means of standard hybrid functionals provided that the value of the U parameter is adequately chosen. Hence, these methods offer an alternative efficient computational scheme to correct LDA and GGA approaches to adequately describe the electronic structure and magnetic coupling in large molecular magnetic systems, although at the expenses of introducing an empirical (U) parameter. For all investigated copper dinuclear systems, the LDA+U and GGA+U approaches lead to an improvement in the description of magnetic properties over the original LDA and GGA schemes with an accuracy similar to that arising from the hybrid B3LYP functional, by increasing the on‐site Coulomb repulsion with a moderate U value. Nevertheless, the introduction of an arbitrary U value in the 0–10 eV range most often provides the correct ground‐state spin distribution and the correct sign of the magnetic coupling constant. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009
Synthesis and laser activity of halo‐acridinedione derivatives
Authors: Kaya Muharrem , Yıldırır Yılmaz , Türker Lemi
Published: March 2009

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Synthesis of 10‐(halophenyl)‐9‐(4‐methoxyphenyl)‐3,4,6,7,9,10‐hexahydroacridine‐1,8‐(2H,5H)‐dione derivates have been prepared and their absorption, emission, and laser properties have been evaluated. The structures of all the synthesized compounds were characterized by spectroscopic methods IR, 1H NMR, 13C‐APT, MS, and elemental analysis. J. Heterocyclic Chem., (2009).
Retro‐ene reactions in heterocyclic synthesis. II. A facile synthetic method for 4‐hydroxy‐2‐pyridones
Authors: Ito Kunio , Miyajima Shingo
Published: March 2009

Schiff's bases 1 derived from ketones and t‐butylamine reacted with diphenyl malonate, diphenyl methyl‐malonate and diphenyl phenylmalonate to give 4‐hydroxy‐2‐pyridones 4–6. Schiff's bases b on reaction with trimethyl methanetricarboxylate afforded 4‐hydroxy‐3‐methoxycarbonyl‐2‐pyridones 12.
The first synthesis of pyrido[2,1‐a]phthalazinium system and its three thieno‐fused analogues
Authors: Gronowitz Salo , Messmer András , Timári Géza
Published: March 2009

Substituted biaryl compounds 9, 14–16 were synthesized through Pd(0)‐catalyzed cross coupling reactions between boronic acids or tin derivatives and aryl halides. N‐Amination, and subsequent ring closure resulted in the new angularly‐fused pyrido[1,2‐b]pyridazinium systems 1–4. The use of silver oxide as a cocatalyst in the couplings of tin derivatives was essential in order to obtain rapid reaction and better yields. Structures were determined by 1H nmr and 13C nmr spectra.
Cyclization of N‐cyanovinyl‐lactam imines to condensed 4‐aminopyridines or substituted aminopyrazole
Authors: Pätzel Michael , Ushmajev Alexej , Liebscher Jürgen , Granik Vladimir , Grisik Sofia , Polievktov Mikhail
Published: March 2009

N‐Cyanovinyl‐lactam imines 2 react with hydrazine giving aminopyrazole 4a while lactam imine 3 is split off. Treatment of 2 with strong bases gives intramolecular cyclization to condensed 4‐aminopyridines 5. The progress of reaction was observed by polarographic method.
Palladium‐ or ruthenium‐catalyzed synthesis of 2‐phenylindoles
Authors: Izumi Taeko , Yokota Toshiko
Published: March 2009

Allyl α‐phenyl‐2‐aminophenethyl carbonates undergo a smooth decarboxylation‐dehydrogenation reaction to afford 2‐phenylindole derivatives in acetonitrile at 80° in the presence of palladium complex as catalyst. In the reaction, the ruthenium hydride complex showed more effective catalytic activities. 2‐Phenylindoles were also prepared from the corresponding α‐phenyl‐2‐aminophenethylalcohols and allyl methyl carbonate by ruthenium‐catalyzed cyclization.
Synthesis of 2,10‐diphenyl‐2H‐pyridazino[4,5‐b]quinolin‐1‐one and 2,3‐dihydro‐9‐phenyl‐2‐phenylamino‐1H‐pyrrolo[3,4‐b]quinolin‐1‐one derivatives as peripheral‐type benzodiazepine receptor ligands
Authors: Anzini M. , Cappelli A. , Vomero S. , Cagnotto A. , Skorupska M.
Published: March 2009

The reaction of 2‐chloromethyl‐3‐ethoxycarbonyl‐4‐phenylquinoline with phenylhydrazine, afforded 2,3‐dihydro‐9‐phenyl‐2‐phenylamino‐1H‐pyrrolo[3,4‐b]quinolin‐1‐one derivatives2along with a major amount of 3‐ethoxycarbonyl‐4‐phenylquinoline‐2‐carboxaldehyde phenylhydrazone4a. The geometric isomers of phenylhydrazone4a, displaying solvent‐dependentE‐Zisomerism, were isolated, characterized by1H‐nmr and mass spectra, and theZ‐form easily cyclized to pyridazino[4,5‐b]quinoline derivative5a. Analogously, compounds2b, 2c, 4b,4c, 5band5cwere obtained. The title compounds were tested as potential ligands for central and peripheral‐type of benzodiazepine receptors, and the results are reported.
Reaction of N,N'‐dialkyldithiodianilines with β‐ketoesters. A new synthesis of N‐alkyl‐2‐acyl‐3‐oxo‐3,4‐dihydro‐1,4‐benzothiazines
Authors: Trapani Giuseppe , Latrofa Andrea , Reho Antonia , Franco Massimo , Liso Gaetano
Published: March 2009

The title compounds 3a‐j together with the N‐alkylacylketene S,N‐acetals 12a‐j were obtained by reaction of N,N'‐dialkyldithiodianilines with β‐ketoesters compounds. A possible reaction pathway is suggested.
Tricyclic heteroaromatic systems. 1,2,4‐triazolo[1,5‐a]quinoxaline
Authors: Catarzi Daniela , Cecchi Lucia , Colotta Vittoria , Filacchioni Guido , Melani Fabrizio
Published: March 2009

The parent 1,2,4‐triazolo[1,5‐a]quinoxaline was prepared by a few‐step reaction from ethyl N1‐(2‐nitrophenyl)‐N3‐ethoxalyloxamidrazonate, which afforded the key intermediate diethyl 1‐(2‐nitrophenyl)‐1,2,4‐triazole‐3,5‐dicarboxylate in satisfactory yield. The latter was cyclized, hydrolyzed, decarboxylated, reduced and dehydrogenated to yield the title compound.
Formation of heterocyclic products in michael reactions of ascorbic acid with α,β‐unsaturated compounds. 3rd communication . Structural analysis of michael adducts of ascorbic acid by 13C‐nmr spectroscopy in the solid state
Authors: Eger Kurt , Schmidt Mathias , Albert Klaus , Schmid Jutta
Published: March 2009

The structure of the Michael adducts of ascorbic acid (AA) and AA‐6‐palmitate with acrolein can be unambiguously determined by using 13C‐nmr solid state spectroscopy.
Syntheses and photophysical properties of some 5(2)‐aryl‐2(5)‐(4‐pyridyl)oxazoles and related oxadiazoles and furans
Authors: Herbert Hall J. , Chien Joseph Yuming , Kauffman Joel M. , Litak Peter T. , Adams Jeffrey K. , Henry Ronald A. , Hollins Richard A.
Published: March 2009

A number of 5‐aryl‐2‐(4‐pyridyl)oxazoles, a 2‐aryl‐5‐(4‐pyridyl)oxazole, the related oxadiazole and furan, several 2‐(4‐pyridyl)cycloalkano[d]oxazoles, and many of their quaternary salts were prepared. No single standard synthesis was effective for preparation of more than a few of the 25 free bases described; methods often unique to a base were employed. Minor variations in structure sometimes produced large differences in absorption and emission wavelengths, as well as in the magnitude of the extinction coefficient. The salts are of interest as laser dyes, scintillation fluors, biological stains, and shifters for luminescent solar concentrators.
Assignment of the NMR spectra of a potent ribonucleotide reductase inactivator ‐ utilization of HMQC‐TOCSY to establish connectivities in exchange broadened spectra
Authors: Blumenkopf Todd A. , Crouch Ronald C. , Martin Gary E.
Published: March 2009

Inverted and Suppressed Direct Response (IDR and SDR, respectively) HMQC‐TOCSY experiments are evaluated relative to the conventional HMQC‐TOCSY experiment in the assignment of the congested proton and carbon spectra of a 2‐acetylpyridine thiocarbonohydrazone used to potentiate the antiviral drug acyclovir. Spectra with moderate overlap can be most expeditiously interpreted using the inverted direct response HMQC‐TOCSY variant; spectra with severe overlap can be more readily interpreted if direct responses are suppressed.
Polycondensed nitrogen heterocycles. Part24. Pyrrolo[3,4‐c]isoquinolinone by thermal rearrangement of a pyrrolylbenzotriazinone
Authors: Cirrincione Girolamo , Almerico Anna Maria , Dattolo Gaetano , Aiello Enrico , Diana Patrizia , Mingoia Francesco
Published: March 2009

Rearrangement under acidic conditions of the pyrrolylbenzotriazinone7afforded the pyrrolylbenzamides10and11. By thermal rearrangement instead, the first fully aromatic derivative of the pyrrolo[3,4‐c]isoquinoline ring system9was obtained.
1,2,4‐Triazolo[4,3‐c]pyrimidines from 4‐acylhydrazinopyrimidines
Authors: Cocco Maria Teresa , Congiu Cenzo , Maccioni Antonio , Onnis Valentina
Published: March 2009

The reaction of N1‐acetylacetamidrazones 1 with N‐[bis(methylthio)methylene]cyanamide (2) at room temperature in the presence of potassium carbonate in dimethyl sulfoxide affords good yields of ethyl 4‐acylhydrazino‐2‐amino‐6‐methylthio‐5‐pyrimidine carboxylate 3. By briefly refluxing compounds 3 in dimethyl sulfoxide, 1,2,4‐triazolo[4,3‐c]pyrimidine derivatives 4 were obtained. When equimolecular amounts of N1‐acylacetamidrazones and compounds 2 were refluxed in dimethyl sulfoxide/toluene, compounds 4 were obtained directly.
Tautomerism in quinaldyl ketones
Authors: Douglass James E. , Michelena Elba , Ataei Ali , Dotson Darin L. , Lo Herng‐Hsiang
Published: March 2009

The quinaldyl ketone, 4‐phenyl‐3‐(quinolin‐2‐yl)‐butan‐2‐one was prepared by two methods: (a) benzylation of 1‐(1H‐quinolin‐2‐ylidene)propan‐2‐one in the presence of sodium hydride in dimethylformamide and (b) by the benzylative demethoxycarbonylation of methyl 2‐(1H‐quinolin‐2‐ylidene)‐3‐oxobutanoate in the presence of lithium bromide in hexamethylphosphoramide at 135°. In the absence of acid, the compound exists exclusively in the tautomeric form, 4‐phenyl‐3‐(1H‐quinolin‐2‐ylidene)butan‐2‐one.
Large scale synthesis of 4‐ethylpyrimidine
Authors: Butters M.
Published: March 2009

The reaction of methyl propionyl acetate with formamidine acetate in the presence of sodium methoxide produces 6‐ethyl‐4(3H)‐pyrimidinone (1) in 67% isolated yield. Reaction with phosphorus oxychloride and subsequent catalytic hydrogenolysis affords 4‐ethylpyrimidine (3) in 41% overall yield.
Self‐determination group or extra‐legal governance agency? The multifaceted nature of the Oodua people's congress in Nigeria
Authors: Guichaoua Yvan
Published: March 2009

The paper contributes to the understanding of the origins of violent non‐legal organisations in West Africa by focusing on the emergence and the evolution of the Oodua People's Congress (OPC), a movement aiming at defending the interests of the Yoruba people in Nigeria. It discusses the causes of its gradual transformation from a self‐determination group ready to use political violence into an agency of local extra‐legal governance tolerated by official federal authorities. This evolution may reflect the normalisation of the OPC in Nigeria's weak democracy. Copyright © 2009 John Wiley & Sons, Ltd.
The female gonad in two species of Microplana (Platyhelminthes, Tricladida, Rhynchodemidae): Ultrastructural and cytochemical investigations
Authors: Falleni Alessandra , Lucchesi Paolo , Ghezzani Claudio , McDonald Jillian C. , Jones Hugh D.
Published: March 2009

The female gonad of the land planarians Microplana scharffi and Microplana terrestris consists of two small germaria located ventrally in the anterior third of the body and of two ventro‐lateral rows of oblong vitelline follicles distributed between the intestinal pouches. Both these structures are enveloped by a tunica composed of an outer extracellular lamina and an inner sheath of accessory cells. Oocyte maturation is characterized by the appearance of chromatoid bodies and the development of endoplasmic reticulum and Golgi complexes. These organelles appear to be correlated with the production of egg granules with a fenestrated/granular content of medium electron density, about 4–5 μm in diameter, which remain dispersed in the ooplasm of mature oocytes. On the basis of cytochemical tests showing their glycoprotein composition, and their localization in mature oocytes, these egg granules have been interpreted as yolk. In the vitelline follicles, vitellocytes show the typical features of secretory cells with well‐developed rough endoplasmic reticulum and Golgi complexes involved in the production of eggshell globules and yolk. The eggshell globules, which appear to arise from repeated coalescences of two types of Golgi‐derived vesicles, contain polyphenols and, when completely mature, they measure about 1–1,2 μm in diameter and show a meandering/concentric content pattern as is typical of the situation observed in most Proseriata and Tricladida. Mature vitellocytes also contain a large amount of glycogen and lipids as further reserve material. On the basis of the ultrastructural features of the female gonad and in relation to the current literature the two species of rhynchodemids investigated appear to be closely related to the freshwater planarians belonging to the family Dugesiidae. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.
Nanocarbon materials: probing the curvature and topology effects using phonon spectra
Authors: Gupta Sanju , Saxena Avadh
Published: March 2009

Much has been learned from the use of resonance Raman spectroscopy and high‐resolution transmission electron microscopy techniques about the micro‐/nanoscopic structure of various nanostructured carbons. However, they still possess some features that are not entirely understood particularly in terms of topological characteristics, which go beyond making a distinction with just the geometrical structure at nanoscale. To effectively utilize the potential of these materials for technological needs, understanding both the geometrical and topological structure and perhaps relating these attributes to physical (optical/electronic, lattice vibrational) properties become indispensable. Here, we make an attempt to describe the differences between various nanostructures and provide geometrical and topological property assessment semiquantitatively by monitoring the phonon spectra using resonance Raman spectroscopy thereby also capturing the electronic spectra. We elucidate the notion of global topology and curvature for a range of technologically important nanoscale carbons including tubular (single‐, double‐ and multiwalled nanotubes, peapod), spherical (hypo‐ and hyperfullerenes, onion‐like carbon) and complex (nanocones, nanohorns, nanodisks and nanorings) geometries. To demonstrate the proof‐of‐concept, we determined the variation in the prominent Raman bands of the respective materials, represented as D, G and D* (the overtone of D) bands, as a possible topological or curvature trend due to their sensitivity toward structural modification. The latter arises from local topological defects such as pentagons giving rise to curved nanocarbons. In this study, we provide systematics of their variation with respect to their geometric forms and compare with highly oriented pyrolytic graphite and monolayer graphene since the nanocarbons discussed are their derivatives. Once established, this knowledge will provide a powerful machinery to understand newer nanocarbons and indeed point to an unprecedented emergent paradigm of global topology/curvature → property → functionality relationship. We emphasize that these concepts are applicable to other topologically distinct nanomaterials, which include boron‐nitride (BN) nanotubes and nanotori, helical gold nanotubes and Möbius conjugated organics. Copyright © 2009 John Wiley & Sons, Ltd.
Multitoxin extraction and detection of trichothecenes in cereals: an improved LC‐MS/MS approach
Authors: Santini Antonello , Ferracane Rosalia , Somma Maria Carmela , Aragón Alejandro , Ritieni Alberto
Published: March 2009

BACKGROUND: Many multiresidual methods to evaluate natural occurrence of Fusarium toxins are already reported in the scientific literature but a new rapid, reliable, cost‐efficient and high‐sensitivity method for the simultaneous determination of several fusariotoxins is always welcome. Nivalenol (NIV), deoxynivalenol, fusarenon‐X (FUS‐X), 3‐acetyldeoxynivalenol, diacetoxyscirpenol (DAS), HT‐2 toxin, T‐2 toxin, neosolaniol (NEO), zearalanone and zearalenone (ZON) belong to the most common mycotoxins in food matrix grains, e.g., wheat and maize. The proposed method is a multitoxin analytical method that combines high‐performance liquid chromatography (HPLC), atmospheric pressure chemical ionization (APCI), triple‐quadrupole tandem mass spectrometry (LC‐MS/MS) under the selected reaction monitoring (SRM) mode, and it is focused on the optimization of the sample preparation without the need for any cleanup.

RESULTS: Three different methods for sample preparation and for the simultaneous extractions of the above‐mentioned fusariotoxins were tested: two of these were followed by a different cleanup step for comparison, while the extraction method proposed in this work, which uses an 84% (v/v) acetonitrile aqueous solution, sample homogenization and subsequent filtration, was validated without any further cleanup step.

CONCLUSION: Calibration curves for all analytes are linear, except DAS, HT‐2 and ZON, over the working range of 10–1000 µg kg−1. The calibration curve of DAS was linear between 10 and 500 µg kg−1, although the curves of HT‐2 and ZON were linear in the range 10–250 µg kg−1. Squared correlation coefficients (R2) were in the range 0.995–0.998 for the all point calibration curves. The lowest limits of detection (LOD) were found for DON and ZAN with 0.5 and 0.2 µg kg−1, respectively, while the highest LODs were obtained for NIV, FUS‐X and NEO, with 3.3 µg kg−1 for each toxin. Copyright © 2009 Society of Chemical Industry
Towards more relaxed conditions for a gamma‐ray laser: Methods to realize induced transparency for nuclear resonant gamma radiation
Authors: Odeurs J. , Hoy G.R. , Rostovtsev Y. , Shakhmuratov R.N.
Published: March 2009

Nuclear quantum optics deals with the resonant interaction of gamma‐radiation and nuclei, generally incorporated in a solid‐state material. Single gamma‐rays interact with an ensemble of nuclei. The properties of the resonantly forward‐scattered gamma‐radiation depend on the details of the interaction. An external modification of the nuclear energies will influence the interactions, and hence the properties of the radiation. Several techniques are proposed to reduce the resonant absorption of the gamma‐rays, creating a nuclear medium that is partially transparent: nuclear‐level‐mixing induced transparency, modification of nuclear levels by means of an optical laser, phase‐shift‐induced transparency. Interference is crucial in all this. The partial transparency could be exploited to study special effects such as slow gamma‐radiation and gain without population inversion. It could also be of importance for the realization of a gamma‐ray laser.
Antibiotics: Natural products essential to human health
Authors: Demain Arnold L.
Published: March 2009

For more than 50 years, natural products have served us well in combating infectious bacteria and fungi. Microbial and plant secondary metabolites helped to double our life span during the 20th century, reduced pain and suffering, and revolutionized medicine. Most antibiotics are either (i) natural products of microorganisms, (ii) semi‐synthetically produced from natural products, or (iii) chemically synthesized based on the structure of the natural products. Production of antibiotics began with penicillin in the late 1940s and proceeded with great success until the 1970–1980s when it became harder and harder to discover new and useful products. Furthermore, resistance development in pathogens became a major problem, which is still with us today. In addition, new pathogens are continually emerging and there are still bacteria that are not eliminated by any antibiotic, e.g., Pseudomonas aeruginosa. In addition to these problems, many of the major pharmaceutical companies have abandoned the antibiotic field, leaving much of the discovery efforts to small companies, new companies, and the biotechnology industries. Despite these problems, development of new antibiotics has continued, albeit at a much lower pace than in the last century. We have seen the (i) appearance of newly discovered antibiotics (e.g., candins), (ii) development of old but unutilized antibiotics (e.g., daptomycin), (iii) production of new semi‐synthetic versions of old antibiotics (e.g., glycylcyclines, streptogrammins), as well as the (iv) very useful application of old but underutilized antibiotics (e.g., teicoplanin). © 2009 Wiley Periodicals, Inc. Med Res Rev, 29, No. 6, 821–842, 2009
Anatomical information is needed in ultrasound imaging of muscle to avoid potentially substantial errors in measurement of muscle geometry
Authors: Bénard Menno R. , Becher Jules G. , Harlaar Jaap , Huijing Peter A. , Jaspers Richard T.
Published: March 2009

This study validates two‐dimensional (2D) ultrasound measurements of muscle geometry of the human medial gastrocnemius (GM) and investigates effects of probe orientation on errors in these measurements. Ultrasound scans of GM muscle belly were made both on human cadavers (n = 4) and on subjects in vivo (n = 5). For half of the cadavers, ultrasound scans obtained according to commonly applied criteria of probe orientation deviated 15° from the true fascicle plane. This resulted in errors of fascicle length and fascicle angle up to 14% and 23%, respectively. Fascicle‐like structures were detectable over a wide range of probe tilt and rotation angles, but they did not always represent true fascicles. Errors of measurement were either linear or quadratic functions of tilt angle. Similar results were found in vivo. Therefore, we conclude that similar errors are likely to occur for in vivo measurements. For all cadavers, at the distal end of GM, the true fascicle plane was shown to be perpendicular to the distal aponeurosis. Using transverse images of GM to detect the curvature of the deep aponeurosis at the distal end of the muscle belly is a simple strategy to help identify the fascicle plane. For subsequent longitudinal imaging, probe alignment within this plane will help minimize measurement errors of fascicle length, fascicle angle, and muscle thickness. Muscle Nerve, 2009
Characterisation of tannin‐containing herbal drugs by HPLC
Authors: Møller Charlotte , Hansen Steen Honoré , Cornett Claus
Published: March 2009

Introduction

Herbal drugs containing tannins are characterised in the European Pharmacopoeia by their tannin content analysed by the old, nonspecific, colorimetric Folin–Ciocalteu method. The result of the analysis is a single figure relating to the content of tannins, but this does not provide much information on the identity or status of the herbal drug.

Objective

In the present paper methods for obtaining more detailed information of the constituents in these herbal drugs are described.

Methodology

The methods developed are based on a reversed‐phase gradient HPLC system coupled to DAD, fluorescence, electrochemical and MS detectors.

Results

The HPLC system developed provides characteristic fingerprints of the herbal drugs when using UV detection at 250 nm. The fingerprints may be used for identification of tannin‐containing herbal drugs. Methanolysis of the herbal drug generated methyl gallate and ellagic acid, which were analysed in the HPLC system. The molar ratio between methyl gallate and ellagic acid may also be used for the identification of herbal drugs.

Conclusions

An HPLC system equipped with selective detectors was shown to be valuable in the identification of herbal tannin. Most promising was fingerprinting using UV detection, but methanolysis followed by HPLC also proved useful. Copyright © 2009 John Wiley & Sons, Ltd.
The effect of injection molding conditions on the morphology of polymer structural foams
Authors: Barzegari M. Reza , Rodrigue Denis
Published: March 2009

This study investigates the relations between processing conditions and morphology of injection molded structural foams. The samples were produced by adjusting five process parameters (blowing agent concentration, mold temperature, melt temperature, injection pressure, and back pressure) at four different levels. The experiments were based on the design of experiments (DOE) analysis with a Taguchi method, and the results were used to determine the optimum conditions to produce high quality foams in terms of low skin thickness, small cell sizes, and narrow cell size distribution combined with low foam density and high cell density. The conclusions revealed that blowing agent concentration and injection pressure were the most influential factors. Using the optimum conditions predicted from the DOE, a validation test was performed and confirmed the results. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
The influence of the stress relaxation and creep recovery times on the viscoelastic properties of open cell foams
Authors: Greco Antonio , Lionetto Francesca
Published: March 2009

The aim of this work is to study the mechanical behavior of flexible polyurethane foams used in cushioning applications. In particular, the differences between slow recovery (SR) and fast recovery (FR) foams are highlighted. To characterize the flexible polyurethane foams, creep and hysteresis tests were performed at different strain rate, stress levels, and temperatures. Significant differences were observed between the SR and FR foams, particularly in terms of residual deformation after unloading, hysteresis area, and creep behavior at different stress levels. Creep compliance at different stress levels was compared with a Voigt‐Kelvin model. Stress–strain loading curves were compared with a phenomenological model originally modified to account for the strain rate dependence. In both cases, it is possible to show that the main differences observed in the behavior of the foams are due to the different relaxation and recovery times of the foams. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Improving homework accuracy: Interdependent group contingencies and randomized components
Authors: Reinhardt Danielle , Theodore Lea A. , Bray Melissa A. , Kehle Thomas J.
Published: March 2009

Homework is an often employed teaching strategy that has strong positive effects on academic achievement across grade levels, content areas, and student ability levels. To maximize academic learning, accuracy of homework should be addressed. The present investigation employed a multiple‐baseline design across academic behaviors to examine the efficacy of randomization of the interdependent group contingency on the homework accuracy of six fourth‐grade students enrolled in a general education class. Results demonstrated that the interdependent group contingency coupled with randomly selected components improved accuracy of homework performance. Specifically, participants demonstrated gains in all three subject areas. Limitations and future research are also addressed. © 2009 Wiley Periodicals, Inc.
Building a foundation for structure‐based cellulosome design for cellulosic ethanol: Insight into cohesin‐dockerin complexation from computer simulation
Authors: Xu Jiancong , Crowley Michael F. , Smith Jeremy C.
Published: March 2009

The organization and assembly of the cellulosome, an extracellular multienzyme complex produced by anaerobic bacteria, is mediated by the high‐affinity interaction of cohesin domains from scaffolding proteins with dockerins of cellulosomal enzymes. We have performed molecular dynamics simulations and free energy calculations on both the wild type (WT) and D39N mutant of the C. thermocellum Type I cohesin‐dockerin complex in aqueous solution. The D39N mutation has been experimentally demonstrated to disrupt cohesin‐dockerin binding. The present MD simulations indicate that the substitution triggers significant protein flexibility and causes a major change of the hydrogen‐bonding network in the recognition strips—the conserved loop regions previously proposed to be involved in binding—through electrostatic and salt‐bridge interactions between β‐strands 3 and 5 of the cohesin and α‐helix 3 of the dockerin. The mutation‐induced subtle disturbance in the local hydrogen‐bond network is accompanied by conformational rearrangements of the protein side chains and bound water molecules. Additional free energy perturbation calculations of the D39N mutation provide differences in the cohesin‐dockerin binding energy, thus offering a direct, quantitative comparison with experiments. The underlying molecular mechanism of cohesin‐dockerin complexation is further investigated through the free energy profile, that is, potential of mean force (PMF) calculations of WT cohesin‐dockerin complex. The PMF shows a high‐free energy barrier against the dissociation and reveals a stepwise pattern involving both the central β‐sheet interface and its adjacent solvent‐exposed loop/turn regions clustered at both ends of the β‐barrel structure.
Rational redesign of neutral endopeptidase binding to merlin and moesin proteins
Authors: Niv Masha Y. , Iida Katsuyuki , Zheng Rong , Horiguchi Akio , Shen Ruoqian , Nanus David M.
Published: March 2009

Neutral endopeptidase (NEP) is a 90‐ to 110‐kDa cell‐surface peptidase that is normally expressed by numerous tissues but whose expression is lost or reduced in a variety of malignancies. The anti‐tumorigenic function of NEP is mediated not only by its catalytic activity but also through direct protein–protein interactions of its cytosolic region with several binding partners, including Lyn kinase, PTEN, and ezrin/radixin/moesin (ERM) proteins. We have previously shown that mutation of the K19K20K21 basic cluster in NEPs' cytosolic region to residues QNI disrupts binding to the ERM proteins. Here we show that the ERM‐related protein merlin (NF2) does not bind NEP or its cytosolic region. Using experimental data, threading, and sequence analysis, we predicted the involvement of moesin residues E159Q160 in binding to the NEP cytosolic domain. Mutation of these residues to NL (to mimic the corresponding N159L160 residues in the nonbinder merlin) disrupted moesin binding to NEP. Mutation of residues N159L160Y161K162M163 in merlin to the corresponding moesin residues resulted in NEP binding to merlin. This engineered NEP peptide–merlin interaction was diminished by the QNI mutation in NEP, supporting the role of the NEP basic cluster in binding. We thus identified the region of interaction between NEP and moesin, and engineered merlin into a NEP‐binding protein. These data form the basis for further exploration of the details of NEP‐ERM binding and function.
Aerial electrostatic‐charged sprays for deposition and efficacy against sweet potato whitefly (Bemisia tabaci) on cotton
Authors: Latheef Mohamed A , Carlton James B , Kirk Ivan W , Hoffmann W Clint
Published: March 2009

Background: The efficacy of aerial electrostatic‐charged sprays was evaluated for spray deposit characteristics and season‐long control of sweet potato whitefly (SWF), Bemisia tabaci Genn. biotype B (aka B. argentifolii Bellows & Perring), in an irrigated 24 ha cotton field. Treatments included electrostatic‐charged sprays at full and half active ingredient (AI) label rate, uncharged sprays and conventional sprays applied with CP nozzles at full label rate with several different insecticides.

Results: Spray droplet size was significantly smaller for electrostatic‐charged sprays than for conventional sprays in top‐ and mid‐canopy locations. The seasonal mean numbers of viable eggs and live large nymphs on cotton treated with electrostatic‐charged sprays were comparable with those on cotton treated with conventional applications. Lethal concentration (LC50) for adults for electrostatic‐charged sprays was comparable with that for conventional sprays.

Conclusion: The amenability of electrostatic‐charged sprays to a wide array of pesticides with different chemistries should be a useful tool in combating insect resistance. Results reported here suggest that the potential exists for obtaining increased efficacy against whiteflies using an electrostatic spray charging system, and that additional research will be required to improve charge‐to‐mass (Q/M) ratio in order to increase deposition of pest control materials to the lower surfaces of cotton leaves where the whiteflies reside. Copyright © 2009 Society of Chemical Industry
Defining areas and linking geographical data: an example from New Zealand
Authors: Grimes Arthur , Maré David C. , Morten Melanie
Published: March 2009

This paper develops a match quality statistic to aid researchers in linking regional data that are available at inconsistent levels of aggregation. The match quality statistic developed in the paper allows researchers to make their own decisions regarding the trade‐off between specificity and completeness when choosing a basis for linking such data. We illustrate this statistic with the example of a New Zealand labour economics research project that required different spatial data to be combined. A program to calculate the match quality statistic, coded as a Stata® ado file, is available on request from the authors. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of native silicon oxides on the growth of GaN nanorods on Si(001)
Authors: Hasegawa Shigehiko , Seo Jong‐Uk , Uchida Kanae , Tambo Hiroyuki , Kameoka Hisashi , Ishimaru Manabu , Asahi Hajime
Published: March 2009

Influence of native Si oxides on the growth of GaN nanorods on Si(001) substrates have been investigated. At the initial stage of GaN growth on clean Si(001) substrates at 450 °C, (2x1) reflection high‐energy electron diffraction patterns immediately change into halo patterns, indicating growth of amorphous materials. The cross‐sectional transmission microscopy observation and secondary ion mass spectroscopy measurement reveal that there exists an amorphous Six Ny layer at the GaN/Si interface. This provides the evidence that during the initial growth of GaN on clean Si substrates with out native oxides, nitridation of Si takes place to form amorphous Six Ny as well as GaN. The structural properties and surface morphologies of these interfacial layers affect GaN nanorod growth. By contrast, native oxides act as a mask against nitridation of Si substrates. Since plasma‐activated nitrogen mainly reacts with Ga to form GaN, GaN growth always proceeds under a desired N‐rich growth condition. As a result, GaN nanorods are uniformly grown on Si(001) with native oxides. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discrete luminescence bands in AlGaN‐based quantum wells
Authors: Murotani Hideaki , Yamada Yoichi , Taguchi Tsunemasa , Ishibashi Akihiko , Kawaguchi Yasutoshi , Yokogawa Toshiya
Published: March 2009

The excitation‐power‐density dependent photoluminescence (PL) spectra have been studied for AlGaN‐based quantum wells (QWs) with a well‐layer thickness of 2, 4, and 6 nm. With increasing excitation‐power density, an additional luminescence line was observed at the higher energy side of an initial luminescence line for the QWs with the well‐layer thickness of 4 and 6 nm. The additional line also shifted toward higher energy side with further increasing excitation‐power density. It was found from a theoretical calculation of the transition energy under applied electric field that an energy difference between the additional and the initial lines agreed with an energy separation for a well‐layer‐thickness variation of 2 monolayer for each QW. Therefore, these observations indicated that in the QWs with the well‐layer thickness of 4 and 6 nm, the screening of the internal electric field occurred effectively after the saturation of localized states caused by the interface disorder. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Infrared reflectivity spectra of thin porous aluminum oxide films
Authors: Yakovlev Vladimir A. , Vinogradov Evgeny A. , Novikova Nadezhda N. , Mattei Giorgio , Delplancke‐Ogletree Marie‐Paule
Published: March 2009

Angular dependencies of infrared (50–7500 cm–1) reflectivity spectra of thin porous aluminum oxide films on aluminum had been measured. These spectra show vibrational bands and strong interference bands allowing film thickness and dielectric function calculation. Angular dependencies of interference bands give thicknesses and refractive indices of the films. The refractive indices decrease and hence the film porosities increase with the thickness. The dispersion analysis of the reflectivity spectra below 2000 cm–1 allows us to obtain the film dielectric functions in the fundamental vibrations region. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Physical adsorption vs. chemical binding of undecylenic acid on porous silicon surface: a comparative study of differently functionalized materials
Authors: Pastor E. , Salonen J. , Lehto V.‐P. , Chirvony V. , Matveeva E.
Published: March 2009

To imply miscibility to porous silicon (PSi) used for biomedical purposes a number of functionalization methods are employed. In order to distinguish between a non‐specific surfactant‐like interaction (physical sorption) and chemical binding of unsaturated chemicals (undecylenic acid, UD) to H‐terminated PSi surface we studied the two differently treated materials. Differential scanning calorimetry (DSC) and thermogravimetry (TGA), BET and FTIR measurements were performed with the PSi powder samples (n+ doped). Changes in surface area, weight loss, calorific effect and chemical composition that accompanied the thermal treatment have shown that the physisorbed UD molecules undergo a chemical process (binding) with the Si‐Hx surface groups at about 150 °C in both, N2 inert atmosphere and in a synthetic air, oxidative atmosphere. Controlled conversion of physically sorbed molecules to the chemically attached ones is discussed with respect to methods of surface modification of PSi materials for increasing their biocompatibility. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Assessing the efficiency of mixed effects modelling in quantifying metabolism based drug–drug interactions: usingin vitrodata as an aid to assess study power
Authors: Johnson Trevor N. , Kerbusch Thomas , Jones Barry , Tucker Geoffrey T. , Rostami‐Hodjegan Amin , Milligan Peter A.
Published: March 2009

The clinical assessment of metabolic drug–drug interactions (mDDI) may involve population‐based pharmacokinetic (POPPK) assessment as part of Phase 3 clinical trials. The elements of such POPPK study design have not been linked to prior information fromin vitroexperiments. Usingin vitro–in vivoextrapolation techniques, implemented within Simcyp®algorithms, the influence of POPPK study design (sample size, concentration‐time data points, proportion of the population receiving a concomitant medication (COMED)) was studied in relation to the inhibitory potency of the each COMED. Steady‐state concentrations of a candidate compound (compound X; mainly metabolized by cytochrome P450 enzymes, CYP3A4 and CYP2D6) in the presence and absence of COMEDs (including ketoconazole, fluconazole, quinidine and paroxetine as inhibitors) were analysed using non‐linear mixed effect modelling (NONMEM®). The NONMEM operator was blind to the nature of the COMEDs and the inhibitory effects on model parameters were classified as either statistically (p>0.01 for a change in objective function) or kinetically (COMED effect>2 fold) significant. Using a population study size of 2000, no false‐positive cases were identified and, except in one case, no false‐negative interaction was observed when >2.5% of patients had received an interacting COMED. The findings increase the confidence in the ability of the mixed effects modelling approach to identify ‘true’ interactions. However, they also emphasize the importance of study design and the potential value of using pre‐clinical information fromin vitrostudies. Recent US Food and Drug Administration guidance on mDDI has put more emphasis on the use ofin vitrosystems for detecting and anticipating such effects. Combining these data with the framework of non‐linear mixed effect modelling seems a natural progression in the field of assessing mDDI. Copyright © 2009 John Wiley & Sons, Ltd.
Development and implementation of a team of robotic tractors for autonomous peat moss harvesting
Authors: Johnson David A. , Naffin David J. , Puhalla Jeffrey S. , Sanchez Julian , Wellington Carl K.
Published: March 2009

This paper describes the key system components of a team of three tractors in a peat moss harvesting operation. The behavior and actions of the tractors were designed to mimic manual harvest operations while maintaining a safe operating environment. To accomplish this objective, each of the three tractors was equipped with a bolt‐on automation package, and a human operator (team leader) was given a remote user interface to command and monitor the mission. The automation package included positioning, planning, and control, as well as coordination and perception systems to preserve field harvesting order, detect obstacles, and report physical changes in the operating environment. The system performed more than 100 test field harvesting missions during one season in a working peat bog, including three complete system tests with the end users. © 2009 Wiley Periodicals, Inc.
Conceptions of knowledge in research on students' understanding of the greenhouse effect: Methodological positions and their consequences for representations of knowing
Authors: Jakobsson Anders , Mäkitalo Åsa , Säljö Roger
Published: March 2009

Much of the research on students' understanding of the greenhouse effect and global warming reports poor results. Students are claimed to hold misconceptions and naïve beliefs, and the impact of teaching on their conceptions is also low. In the present study, these results are called into question, and it is argued that they may to a large extent be seen as artifacts of the research methods deployed, in particular when written questionnaires are used. When following students' project work in school over a long period, many of the misunderstandings reported in the literature do not appear. It is argued that the appropriation and use of scientific language when discussing complex socioscientific issues is a gradual process. When observing the language and mediational means students use over time, it is obvious that they are able to identify and use central distinctions in their interactions. They are also able to make productive use of texts and other materials that allow them to successively approximate scientific modes of reasoning. Thus, what students know emerges in communicative practices where they interact with others and with cultural tools in a focused activity. It is argued that students' knowledge of complex multidisciplinary phenomena of this kind may be particularly ill‐suited to conventional questionnaire types of testing. © 2009 Wiley Periodicals, Inc. Sci Ed 93:978–995, 2009