bluuebunny/crossref_metadata_2025 huggingface dataset:
The blood–spinal cord barrier: Morphology and Clinical Implications
Authors: Bartanusz Viktor , Jezova Daniela , Alajajian Betty , Digicaylioglu Murat
Published: March 2011

The blood–spinal cord barrier (BSCB) is the functional equivalent of the blood–brain barrier (BBB) in the sense of providing a specialized microenvironment for the cellular constituents of the spinal cord. Even if intuitively the BSCB could be considered as the morphological extension of the BBB into the spinal cord, evidence suggests that this is not so. The BSCB shares the same principal building blocks with the BBB; nevertheless, it seems that morphological and functional differences may exist between them. Dysfunction of the BSCB plays a fundamental role in the etiology or progression of several pathological conditions of the spinal cord, such as spinal cord injury, amyotrophic lateral sclerosis, and radiation‐induced myelopathy. This review summarizes current knowledge of the morphology of the BSCB, the methodology of studying the BSCB, and the potential role of BSCB dysfunction in selected disorders of the spinal cord, and finally summarizes therapeutic approaches to the BSCB. Ann Neurol 2011;
Many fields interaction: Beam splitters and waveguide arrays
Authors: Mar‐Sarao R. , Soto‐Eguibar F. , Moya‐Cessa H.
Published: March 2011

We study the interaction of many fields. We obtain an effective Hamiltonian for this system by using a method recently introduced that produces a small rotation to the Hamiltonian that allows to neglect some terms in the rotated Hamiltonian. We show that coherent states remain coherent under the action of a quadratic Hamiltonian and by solving the eigenvalue and eigenvector problem for tridiagonal matrices we also show that a system of n interacting harmonic oscillators, initially in coherent states, remain coherent during the interaction.
Neural network‐based controller design of a batch reactive distillation column under uncertainty
Authors: Konakom Kwantip , Kittisupakorn Paisan , Mujtaba Iqbal M.
Published: March 2011

This paper presents the use of neural network‐based model predictive control (NNMPC) incorporated with a neural network (NN) estimator for handling the predefined optimal policy tracking of a batch reactive distillation. The predefined optimal policy has been determined by dynamic optimization strategy. Then, the NNMPC incorporated with the NN estimator has been implemented to provide tracking of the obtained optimal policy. The NN model in the MPC algorithm gives as a one‐step‐ahead prediction of states, and it is therefore used in every iteration over a prediction horizon. Thus, the measured distillate composition at current time, needed as one of NN model inputs, is needed. However, the composition measurement is rarely available online in practice. Hence, an NN estimator is developed to estimate the current composition from the available measured composition with delay of 10 min. Both NNs are trained based on Levenberg–Marquardt algorithm. It has been found that the NNMPC provides satisfactory control performance for set point tracking problems. The robustness of the NNMPC is investigated with respect to parametric plant uncertainties and temperature measurement noise. Comparisons are made with a proportional integral derivative (PID) controller incorporated with the NN estimator. The results show that the NNMPC provides better control performance than the PID controller in all cases. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
Studies of the externally heat‐integrated double distillation columns (EHIDDiC)
Authors: Liu Gongxun , Chen Zidong , Huang Kejin , Shi Zhengyuan , Chen Haisheng , Wang Shaofeng
Published: March 2011

In terms of the separation of an ideal binary mixture of hypothetical components A and B, the synthesis and design of the externally heat‐integrated double distillation columns (EHIDDiC) are studied under the assumption of a constant pressure elevation from the low‐pressure (LP) to the high‐pressure (HP) distillation columns involved. It is found that employing one to three external heat exchangers can be a reasonable design option for the EHIDDiC. When multiple external heat exchangers (e.g. more than three external heat exchangers) have been adopted, the process configuration must be carefully determined because the increase in the number of stages externally heat‐integrated might not necessarily be beneficial to the system performance in this situation. This phenomenon has been caused by the strong mass and heat coupling between the HP and LP distillation columns involved and reflects also the unique characteristic of the EHIDDiC. For the reduction of capital investment, the total external heat exchange areas should be installed through as small a number of heat exchangers as possible and the extreme situation comes to the employment of a single external heat exchanger, thereby requiring subtle wisdom in arranging the total heat transfer areas between the HP and LP distillation columns involved. These insightful findings are of great significance to process synthesis and design. In addition, a novel decentralized control scheme is proposed for the operation of the EHIDDiC. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
A study on the financial approach of risk assessment using chemical accident records in chemical process industries
Authors: Jang Namjin , Koo Jamin , Kim Hosoo , Shin Dongil , Sup Yoon En
Published: March 2011

Usually, risk assessment is a combination of risk analysis and risk appraisal to evaluate the consequences and frequencies of hazardous events. The acceptability of the exposed risk is also judged in the process. In this regard, the financial risk matrix could be a useful tool based on the frequency and expected loss of damage. Thus, it is adopted in this study where a financial approach has been taken in risk assessment; the proposed methodology uses frequencies from chemical accident records and value at risk (VaR). The methodology consists of mainly five steps. It starts with hazard identification, and is followed by adjustment of history‐based accident frequencies by using severity ratios. Then, accident probability and expected damage loss are estimated. The results obtained in the previous two steps are combined to compute VaR for the target process; this value is mapped with financial risk matrix to re‐evaluate accident frequency. As an illustrative case, Texas BP refinery accident in 2005 is studied according to the proposed methodology. The results indicate that the financial risk increased from a low level to a medium high level after the occurrence of the tragic accident. As similar accidents frequently occurred for the same process, the risk of the process should have been increased. This proposed method can reflect this dynamic change in risks with the help of accident records and their impacts. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
Synergistic effect of metal oxides on the flame retardancy and thermal degradation of novel intumescent flame‐retardant thermoplastic polyurethanes
Authors: Lin Mo , Li Bin , Li Qifei , Li Sheng , Zhang Shengqiang
Published: March 2011

The synergistic effects of some metal oxides on novel intumescent flame retardant (IFR)–thermoplastic polyurethane (TPU) composites were evaluated by limiting oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis (TGA), cone calorimetry, and scanning electron microscopy. The experimental data indicated that the metal oxides enhanced the LOI value and restricted the dropping of the composites. The IFR–TPU composites passed the UL‐94 V‐0 rating test (1.6 mm) in the presence of magnesium oxide (MgO) and ferric oxide (Fe2O3) at 35 wt % IFR loading, whereas only the MgO‐containing IFR–TPU composite reached a UL‐94 V‐0 rating at 30 wt % IFR loading. The TGA results show that the metal oxides had different effects on the process of thermal degradation of the IFR–TPU compositions. MgO easily reacted with polyphosphoric acid generated by the decomposition of ammonium polyphosphate (APP) to produce magnesium phosphate. MgO and Fe2O3 showed low flammability and smoke emission due to peak heat release rate, peak smoke production rate, total heat release, and total smoke production (TSP). However, zinc oxide brought an increase in the smoke production rate and TSP values. Among the metal oxides, MgO provided an impressive promotion on the LOI value. The alkaline metal oxide MgO more easily reacted with APP in IFRs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and properties of transparent zinc oxide/silicone nanocomposites for the packaging of high‐power light‐emitting diodes
Authors: Sun Yuping , Gu Aijuan , Liang Guozheng , Yuan Li
Published: March 2011

New transparent zinc oxide (ZnO)/silicone nanocomposites with outstanding integrated properties, including a high UV‐shielding efficiency and transparency, bigger thermal conductivity, and lower dielectric constant, were successfully developed; they were prepared by the uniform dispersion of organic modified nano‐ZnO in a silicone matrix through in situ polymerization. The ZnO precursor was prepared by a direct precipitation method, which was then calcinated at different temperatures to produce nano‐ZnO with various morphologies and sizes. The effects of the size, surface nature, and content of nano‐ZnO on the key properties (e.g., optical and dielectric properties, thermal conductivities) of the composites were systematically investigated. The results show that the organic nano‐ZnO prepared by 3‐methacryloxypropyltrimethoxysilane can increase the dispersion of nano‐ZnO in silicone resin, and the interfacial adhesion between inorganic and organic phases, and consequently improve the integrated properties of nanocomposites. The increase of the particle content and size of ZnO in composites can lead to high thermal conductivity and UV‐shielding efficiency but lower visible‐light transparency, so there is an optimum content and size of ZnO in composites to obtain the best integrated properties of the composites. Specifically, the nanocomposite containing 0.03 wt % organic nano‐ZnO with an average size of 46 ± 0.4 nm not only had a high visible‐light transparency, UV‐shielding efficiency, and thermal conductivity but also possessed a low dielectric constant and loss and met the requirements of high‐performance electronic packaging for high‐power light‐emitting diodes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Ultraviolet photopolymerization induced by a triazine derivative
Authors: Jiang Mingyan , Wang Kemin , Ma Guiping , Jian Lu , Juan Xu , Yu Qiang , Nie Jun
Published: March 2011

2‐(3,4‐Methdioxyphenyl)‐4,6‐bis(trichloromethyl)‐ 1,3,5‐triazine (MBTTR) was used as a photoinitiator for the polymerization of acrylate monomer. Ultraviolet–visible absorption spectroscopy was used to investigate the photochemical behavior during the photophysical process. The photopolymerization kinetics were monitored by real‐time Fourier transform infrared spectroscopy. The polymerization rates of the acrylates were significantly higher than those of the methacrylates. When MBTTR induced the polymerization of trimethylolpropane triacrylate, there was an optimum polymerization rate and the final conversion was obtained at 0.1 wt % MBTTR. MBTTR was an inefficient photoinitiator for ethyl vinyl. The final conversions of tripropylene glycol diacrylate induced by MBTTR and triazine/1,3‐benzodioxole were similar. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Supramolecular bionanocomposites, part 2: Effects of carbon nanoparticle surface functionality on polylactide crystallization
Authors: Sobkowicz Margaret J. , Sosa Rodolfo , Dorgan John R.
Published: March 2011

Two types of supramolecular carbon nanostructures, carbon nanospheres (CNS) and multiwalled carbon nanotubes, (MWCNTs) are investigated for their potential as nanofillers in the bioplastic polylactide (PLA). Modification of the surfaces of both carbon nanostructures by covalent attachment of dodecylamine is accomplished and the effects of this compatibilizing functionality are explored. Crystallization kinetics, thermal properties, and mechanical properties are investigated. Addition of a small amount of carbon to the PLA increases the thermal stability by as much as 20–30°C. Incorporation of the MWCNT and CNS increases the heat distortion temperature by up to 10°C. Speed up in crystallization rate is observed for small to intermediate loading levels; however, at higher nanofiller loading, the rate decreases. Functionalized nanostructures are more effective at increasing crystallization rates than unfunctionalized nanostructures. It is concluded that the dodecylamine (DDA) grafted to the carbon surfaces aids in dispersing the materials and preventing aggregation, thereby providing higher surface area for heterogeneous nucleation of the biopolymer. The resulting materials are composed of the supramolecular carbon nanostructure embedded in a semicrystalline biopolymer matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Rice hull biocomposites, part 2: Effect of the resin composition on the properties of the composite
Authors: Quirino Rafael L. , Larock Richard C.
Published: March 2011

A free radical thermoset resin consisting of a copolymer of conjugated linseed oil (CLO) or conjugated soybean oil (CSO), n‐butyl methacrylate (BMA), divinylbenzene (DVB), and maleic anhydride (MA) has been reinforced with rice hulls. Composites containing 70 wt % of the filler were compression molded, the conjugated oil content in the resin was kept constant at 50 wt %, and the relative amounts of BMA, DVB, and MA were varied to afford composites with different resin compositions. Tensile tests, DMA, thermogravimetric analysis, and Soxhlet extraction of the different composites prepared have been used to establish the relationship between resin composition and the properties of the composites. Overall, the mechanical properties tend to improve when MA is introduced into the resin. Scanning electron microscopy of selected samples showed a better filler–resin interaction for MA‐containing composites and samples prepared from CLO exhibit better properties than those prepared from CSO. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Measurement of the variation of crystal lattice structures of ethylene copolymers with high‐resolution cryogenic FTIR spectroscopy
Authors: Su Zhiqiang , Li Qing , Cao Li , Chen Xiaonong
Published: March 2011

High‐resolution cryogenic Fourier transform infrared spectroscopy (FTIR) was used to measure the variation of the unit cell volume of ethylene‐octene copolymers (EG) in this study. It was found that both the comonomer content and thermal history have great influence on the crystal lattice structure of ethylene polymers. With the increase of the octene content, the unit cell volume of EG copolymers expand, and quenching treatment favors the increase of distance between two molecular chains in orthorhombic crystals and causes more crystal lattice deformation. Compared with traditional wide‐angle X‐ray diffraction method, high‐resolution cryogenic FTIR spectroscopy, as a powerful technique for measuring the changes of crystal lattice structures of polyethylene and ethylene copolymers, can provide more accurate information on the characterization of the changes of crystal lattice structures of semicrystalline polymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
High activity of rare earth tetrahydroborates for ring‐opening polymerization of ω‐pentadecalactone
Authors: Nakayama Yuushou , Watanabe Naoki , Kusaba Keisuke , Sasaki Kenta , Cai Zhengguo , Shiono Takeshi , Tsutsumi Chikara
Published: March 2011

Ring‐opening polymerization of ω‐pentadecalactone (PDL) by tetrahydroborate complexes of rare earth metals, Ln(BH4)3(THF)3 (Ln = La (1), Nd (2), Y (3)), was studied. These complexes showed high activity for PDL polymerization in THF at 60°C. Among the complexes 1–3, the neodymium complex 2 was most active. The obtained poly(PDL) was demonstrated to be hydroxy‐telechelic by 1H‐NMR and MALDI‐TOF MS spectroscopy. Biodegradation of the poly(PDL) in compost at 60°C was investigated, where 18% weight loss of the samples was observed after 280 days. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Curing behavior and dielectric properties of hyperbranched poly(phenylene oxide)/cyanate ester resins
Authors: Huang Pingzhen , Gu Aijuan , Liang Guozheng , Yuan Li
Published: March 2011

A novel hyperbranched poly(phenylene oxide) (HBPPO) modified 2,2′‐bis(4‐cyanatophenyl) isopropylidene (BCE) resin system with significantly reduced curing temperature and outstanding dielectric properties was developed, and the effect of the content of HBPPO on the curing behavior and dielectric properties as well as their origins was thoroughly investigated. Results show that BCE/HBPPO has significantly lower curing temperature than BCE owing to the different curing mechanisms between the two systems, the difference also brings different crosslinked networks and thus dielectric properties. The dielectric properties are frequency and temperature dependence, which are closely related with the content of HBPPO in the BCE/HBPPO system. BCE/2.5 HBPPO and BCE/5 HBPPO resins have lower dielectric constant than BCE resin over the whole frequency range tested, while BCE/10 HBPPO resin exhibits higher dielectric constant than BCE resin in the low frequency range (<104 Hz) at 200°C. At 150°C or higher temperature, the dielectric loss at the frequency lower than 102 Hz becomes sensitive to the content of HBPPO. These phenomena can be attributed to the molecular relaxation. Two relaxation processes (α‐ and β‐relaxation processes) are observed. The β‐relaxation process shifts toward higher frequency with the increase of temperature because of the polymer structure and chain flexibility; the α‐relaxation process appears at high temperature resulting from the chain‐mobility effects. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Population structure of the migratory fish Prochilodus lineatus (Characiformes) from rio Grande basin (Brazil), an area fragmented by dams
Authors: Garcez Riviane , Calcagnotto Daniela , De Almeida‐Toledo Lurdes Foresti
Published: March 2011

Prochilodus lineatus (Prochilodontidae, Characiformes) is a migratory species of great economic importance both in fisheries and aquaculture that is found throughout the Jacuí, Paraíba do Sul, Paraná, Paraguay and Uruguay river basins in South America. Earlier population studies of P. lineatus in the rio Grande basin (Paraná basin) indicated the existence of a single population; however, the range of this species has been fragmented by the construction of several dams. Such dams modified the environmental conditions and could have constrained the reproductive migration of P. lineatus, possibly leading to changes in the population genetic structure.

In order to evaluate how genetic diversity is allocated in the rio Grande basin, 141 specimens of P. lineatus from eight collection sites were analysed using polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) with 15 restriction enzymes.

Forty‐six haplotypes were detected, and 70% of them are restricted. The mean genetic variability indexes (h = 0.7721 and π = 1.6%) were similar to those found in natural populations with a large effective size. Fst and Exact Test values indicated a lack of structuring among the samples, and the model of isolation by distance was tested and rejected.

The haplotype network indicated that this population of P. lineatus has been maintained as a single variable stock with some differences in the genetic composition (haplotypes) between samples. Indications of population expansion were detected, and this finding was supported by neutrality tests and mismatch distribution analyses.

The present study focused on regions between dams to serve as a parameter for further evaluations of genetic variability and the putative impact of dams and repopulation programmes in natural populations of P. lineatus. Copyright © 2011 John Wiley & Sons, Ltd.
Eine Bemerkung zur Frage einer sonnennahen interstellaren Absorption
Authors: Schmidt H.
Published: March 2011

Eine von Charlier festgestellte und von Brill behandelte Abhängigkeit der absoluten Helligkeiten der B‐Sterne von der scheinbaren Helligkeit wird neu diskutiert und mit der Existenz einer langgestreckten Dunkelwolke in der Umgebung der Sonne in Zusammenhang gebracht.
Beitrag zur Bestimmung einer Doppelsternbahn
Authors: Harting H.
Published: March 2011

Der folgende Beitrag zur Bestimmung der Bahn des Doppelsternes 42 Comae Berenices beschäftigt sich mit den bis zum Jahr 1891 angestellten Beobachtungen, die in einer bisher nicht veröffentlichten umfangreichen Arbeit untersucht wurden. Dank den seither bekanntgegebenen Messungen sind bereits die Bahnelemente genau bestimmt, so daß sich ein näheres kritisches Eingehen auf die älteren Beobachtungen in dieser Arbeit erübrigt. Es werden zwei Verfahren für die Ableitung der Elemente angegeben, und zwar sowohl aus den Distanzen allein, wie aus diesen zusammen mit den Positionswinkeln. Zum Schluß wird dann das vollständige, aus allen Beobachtungen ermittelte Elementen‐system, sowie dessen mittlere Fehler und die der Gewichtseinheiten von Distanz und Positionswinkel angegeben. Für die zweite Methode wird gleichfalls ein kurzes Zahlenbeispiel mitgeteilt.
Luminol–silver nitrate chemiluminescence enhancement induced by cobalt ferrite nanoparticles
Authors: Shi Wenbing , Wang Hui , Huang Yuming
Published: March 2011

CoFe2O4 nanoparticles (NPs) could stimulate the weak chemiluminescence (CL) system of luminol and AgNO3, resulting in a strong CL emission. The UV–visible spectra, X‐ray photoelectron spectra and TEM images of the investigated system revealed that AgNO3 was reduced by luminol to Ag in the presence of CoFe2O4 NPs and the formed Ag covered the surface of CoFe2O4 NPs, resulting in CoFe2O4–Ag core–shell nanoparticles. Investigation of the CL reaction kinetics demonstrated that the reaction among luminol, AgNO3 and CoFe2O4 NPs was fast at the beginning and slowed down later. The CL spectra of the luminol − AgNO3 − CoFe2O4 NPs system indicated that the luminophor was still an electronically excited 3‐aminophthalate anion. A CL mechanism has been postulated. When the CoFe2O4 NPs were injected into the mixture of luminol and AgNO3, they catalyzed the reduction of AgNO3 by luminol to produce luminol radicals and Ag, which immediately covered the CoFe2O4 NPs to form CoFe2O4–Ag core–shell nanoparticles, and the luminol radicals reacted with the dissolved oxygen, leading to a strong CL emission. With the continuous deposition of Ag on the surface of CoFe2O4 NPs, the catalytic activity of the core–shell nanoparticles was inhibited and a decrease in CL intensity was observed and also a slow growth of shell on the nanoparticles. Copyright © 2011 John Wiley & Sons, Ltd.
Electrochemiluminescence of tris(2,2′‐bipyridyl)ruthenium and its applications in bioanalysis: a review
Authors: Wei Hui , Wang Erkang
Published: March 2011

Electrochemiluminescence (ECL) of tris(2,2’‐bipyridyl)ruthenium(II) [Ru(bpy)32+] is an active research area and includes the synthesis of ECL‐active materials, mechanistic studies and broad applications. Extensive research has been focused on this area, due to its scientific and practical importance. In this mini‐review we focus on the bio‐related applications of ECL. After a brief introduction to Ru(bpy)32+ ECL and its mechanisms, its application in constructing an effective bioassay is discussed in detail. Three types of ECL assay are covered: DNA, immunoassay and functional nucleic acid sensors. Finally, future directions for these assays are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Investigating rhodamine B‐labeled peptoids: Scopes and limitations of its applications
Authors: Birtalan Esther , Rudat Birgit , Kölmel Dominik K. , Fritz Daniel , Vollrath Sidonie B. L. , Schepers Ute , Bräse Stefan
Published: March 2011

The fluorophore rhodamine B is often used in biological assays. It is inexpensive, robust under a variety of reaction conditions, can be covalently linked to bioactive molecules, and has suitable spectral properties in terms of absorption and fluorescence wavelength. Nonetheless, there are some drawbacks: it can readily form a spirolactam compound, which is nonfluorescent, and therefore may not be the dye of choice for all fluorescence microscopy applications. Herein this spirolactam formation was observed by purifying such a labeled peptoid with high performance liquid chromatography (HPLC) and monitored in detail by making a series of analytical HPLC runs over time. Additionally, a small library of eight peptoids with rhodamine B as label was synthesized. Analysis of the absorption properties of these molecules demonstrated that the problem of fluorescence loss can be overcome by coupling secondary amines with rhodamine B. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96: 694–701, 2011.
Development and validation of a liquid chromatography method with electrospray ionization tandem mass spectrometry for the determination of brotizolam residues in beef and commercial whole milk
Authors: Cho Hee‐Jung , Jo Kyul , Yi Hee , Cho Soo Min , Abd El‐Aty A. M. , Kim Min Kyung , Han Sang Beom , Oh Jae Ho , Kwon Chan Hyeok , Shim Jae‐Han , Shin Ho‐Chul
Published: March 2011

In this work, a liquid chromatography–tandem mass spectrometric detection technique was developed and validated for the determination of brotizolam residues in beef muscle and commercial whole milk. This procedure involves the extraction of the analyte from the samples via liquid–solid extraction, and caffeine was used as an internal standard. The analyte was successfully separated on an XTerra‐C18 column, with a mobile phase composed of 0.01% formic acid in acetonitrile and 1 mm ammonium formate–0.01% formic acid in water. The one‐step extraction method evidenced good selectivity, precision (RSD = 9.87–26.47%), and the recovery of the extractable analyte was 92.61–115.98% in the matrices. The limits of quantification ranged between 0.4 and 0.5 µg/kg. The developed method is simple since it requires no additional cleanup procedures. Copyright © 2011 John Wiley & Sons, Ltd.
Anatomical and dynamic volume spline model applied to facial soft tissue
Authors: Ulusoy Ilkay , Akagunduz Erdem , Yirci Murat
Published: March 2011

Biomechanical modeling of soft tissue is a complex problem for achieving realistic surgical simulations, surgical planning, and scientific analysis. In the literature, three categories of biomechanical models: spline based models, spring models, and finite element models (FEMs) are mainly used for dealing with this problem. Among these, spline based models offer relatively fast and realistic soft tissue simulations by utilizing both the spring and FEMs. In this paper, a new dynamic volume spline model for human face skin is proposed and the performance of our model is discussed by estimating the results of facial surgery of three different patients. Face models of the patients are obtained from 3D CT/MR scans by segmenting the skull, muscle, and skin layers. In these face models, the skull and the muscle layers are considered as the rigid boundary for the skin layer and the skin layer is modeled by our dynamic volume spline. The control points of the dynamic volume spline are localized masses with viscoelastic material properties (stiffness, damping, and mass). These parameters are computed from the skin material properties that were published in the literature. Once the face models are generated, facial surgery plannings are simulated. Infact, the pre‐surgery face models are modified according to the surgical plans and the estimated post‐surgery face models are compared with the actual post‐surgery face models. Moreover, in order to discuss the performance of our dynamic volume spline model, the same analyses are performed on the post‐surgery estimations of a conventional tool. Copyright © 2011 John Wiley & Sons, Ltd.
New Pregnane Glycosides from Brucea javanica and Their Antifeedant Activity
Authors: Chen Yue‐Yuan , Pan Qiao‐Dan , Li Dian‐Peng , Liu Jin‐Lei , Wen Yong‐Xin , Huang Yong‐Lin , Lu Feng‐Lai
Published: March 2011

Three new pregnane glycosides, 3‐O‐β‐D‐glucopyranosyl‐(1→2)‐α‐L‐arabinopyranosyl‐(20R)‐pregn‐5‐ene‐3β,20‐diol (1), 3‐O‐α‐L‐arabinopyranosyl‐(20R)‐pregn‐5‐ene‐3β,20‐diol‐20‐O‐β‐D‐glucopyranoside (2), 3‐O‐α‐L‐arabinopyranosyl‐(20R)‐pregn‐5‐ene‐3β,20‐diol‐20‐O‐β‐D‐glucopyranosyl‐(1→2)‐β‐D‐glucopyranoside (3) were isolated along with four known compounds, 4–7, from the leaves and stems of Brucea javanica. Their structures were determined by detailed analyses of 1D‐ and 2D‐NMR spectroscopic data. All of the compounds isolated from Brucea javanica were tested for the antifeedant activities against the larva of Pieris rapae. Compounds 1, 3, and 5 showed significant antifeedant activities after 72 h incubation.
Correlation between Environmental Factors, Chemical Composition, and Antioxidative Properties of Caper Species Growing Wild in Calabria (South Italy)
Authors: Conforti Filomena , Modesto Silvia , Menichini Federica , Statti Giancarlo A. , Uzunov Dimitar , Solimene Umberto , Duez Pierre , Menichini Francesco
Published: March 2011

Twenty samples of two caper species were collected from various natural habitats of Calabria (South Italy). A sample program was designed in order to cover all taxa and morphotypes present in the studied area, trying to correlate ecological conditions, phytochemical content, and biological activities. These species were characterized through the detection, isolation, and capillary GC‐GC/MS quantitative evaluation of chemical markers (phytosterols and vitamin E). The antioxidant activity of MeOH caper extracts was assayed using 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and β‐carotene bleaching tests. The chemical investigation showed a different composition according to the species and the populations. The best free radical (DPPH) scavenging activity was exerted by Capparis orientalis sample C4 (collected near Copanello village, granodiorite sea cliff) and Capparis sicula ssp. sicula sample C5 (collected near Tarsia village, clay soil). Sample C2 (Galatrella Valley, clay soil) showed the highest inhibition of linoleic acid oxidation with more efficacy than propyl gallate, the reference drug.
Characterization of Dihydrofolate Reductases from Multiple Strains of Plasmodium falciparum Using Mathematical Descriptors of Their Inhibitors
Authors: Basak Subhash C. , Mills Denise , Hawkins Douglas M.
Published: March 2011

Two classes of graph‐theoretic molecular descriptors, viz., topological indices (TIs) and atom pairs (APs), have been used to derive high‐quality quantitative structureactivity relationships (QSARs) for inhibitors of dihydrofolate reductases (DHFRs) isolated from the wild and four mutant strains of Plasmodium falciparum. Of the three methods used for QSAR formulation, viz., principal‐components regression (PCR), partial least squares (PLS), and ridge regression (RR), the RR method outperformed the other two. Cohen's kappa values, based on the overlap of significant and insignificant structural descriptors calculated for the QSAR development, show that DHFR from the wild strain is substantially different from the four mutant strains. The differential QSAR approach reported in this study can be used in protocols for the development of drugs to combat drug‐resistant pathogens arising continuously in nature due to mutations. The pairwise kappa values in conjunction with appropriate drug targets and their corresponding set of ligands may be a useful tool in gauging the evolving mutual similarities and dissimilarities of pathogenic organisms from purely computed mathematical descriptors of the ligands.
Phytochemical Constituents and Inhibitory Activity towards Methicillin‐Resistant Staphylococcus aureus Strains of Eryngium Species (Apiaceae)
Authors: Çelik Ali , Aydınlık Nilüfer , Arslan Idris
Published: March 2011

The chemical composition of the essential oils of Eryngium campestre, E. thorifolium, and E. creticum (Apiaceae), growing in the Aegean region of Turkey (Mount Sandras, Denizli), was determined by direct thermal desorption (DTD)‐GC/MS analyses. A total of 49 components were identified in the oils, α‐pinene and hexanal being the major compounds. The three essential oils were also tested for their inhibitory activity of nine different methicillin‐resistant Staphylococcus aureus (MRSA) strains by the agar disc diffusion method. The anti‐MRSA activity of E. thorifolium oil, the most active of the three oils, was comparable with those of the reference antibiotic vancomycin and oregano oil, although somewhat lower.
Evaluation of the in vitro Activity of Dermaseptin 01, a Cationic Antimicrobial Peptide, against Schistosoma mansoni
Authors: de Moraes Josué , Nascimento Carlos , Miura Leiz M. C. V. , Leite José R. S. A. , Nakano Eliana , Kawano Toshie
Published: March 2011

Schistosomiasis is a neglected tropical disease that remains a considerable public health problem worldwide. Since the mainstay of schistosomiasis control is chemotherapy with a single drug, praziquantel, drug resistance is a concern. Here, we examined the in vitro effects of dermaseptin 01 (DS 01), an antimicrobial peptide found in the skin secretion of frogs of the genus Phyllomedusa, on Schistosoma mansoni adult worms. DS 01 at a concentration of 100 μg/ml reduced the worm motor activity and caused the death of all worms within 48 h in RPMI 1640 medium. At the highest sublethal concentration of antimicrobial peptide (75 μg/ml), a 100% reduction in egg output of paired female worms was observed. Additionally, DS 01 induced morphological alterations on the tegument of S. mansoni, and a quantitative analysis carried out by confocal microscopy revealed extensive destruction of the tubercles in a dose‐dependent manner over the concentration range of 50–200 μg/ml. It was the first time that an anthelmintic activity towards schistosomes has been reported for a dermaseptin.
Chemical Composition and Antibacterial Activity of the Essential Oil of Drimys granadensis L.f. Leaves from Colombia
Authors: Gaviria Mauricio , Quijano Clara , Pino Jorge , Madriñán Santiago
Published: March 2011

Drimys granadensis L.f., a native plant from Colombia, has been included in the Vademecum de Plantas Medicinales de Colombia by the Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, due to its widespread use in the folk medicine for the treatment of gastrointestinal ailments. The chemical composition of the essential oil of Drimys granadensis obtained by hydrodistillation of the leaves was analyzed by GC and GC/MS analyses. A total of 85 components were identified, with the major compounds germacrene D (1, 14.7%), sclarene (9.5%), α‐cadinol (7.3%), longiborneol acetate (2, 6.3%), drimenol (4.2%), (Z)‐β‐ocimene (3, 4.2%), α‐pinene (4, 3.2%), and β‐elemene (5, 2.7%). The essential oil was also tested against eight bacteria using the KirbyBauer disk‐diffusion method. Most of the Gram‐positive bacteria tested were susceptible to the D. granadensis essential oil, while the Gram‐negative bacteria tested were not.
A Novel Non‐phenolic Dibenzazecine Derivative with Nanomolar Affinities for Dopamine Receptors
Authors: Robaa Dina , ElDin AbulAzm Shams , Lehmann Jochen , Enzensperger Christoph
Published: March 2011

Dibenzazecines are a novel class of dopamine receptor antagonists, characterized by their high affinities as well as their tendency for D1 selectivity. Hitherto, the most active dibenzazecines were phenolic in nature; a 3‐OH substituent was found to result in the highest affinities. However, the phenolic nature of these compounds mostly renders them unsuitable for in vivo application, due to the poor pharmacokinetic profile, imparted by the phenolic group. A novel dibenzazecine derivative was prepared, with methylenedioxy moiety, connecting C(2) amd C(3), instead of the 3‐OH group. The newly synthesized derivative 3 showed high affinities similar to the lead LE404, displaying nanomolar affinities for all dopamine receptor subtypes. Its dibrominated derivative 4, though exhibiting almost a fivefold decrease in affinities, still displayed nanomolar ones for all dopamine receptors, except for D4. In a functional Ca2+ assay, both compounds 3 and 4 were found to possess antagonistic properties towards the dopamine receptors.
Derivatives of Pheophorbide‐a and Pheophorbide‐b from Photocytotoxic Piper penangense Extract
Authors: Adzhar Kamarulzaman Fadzly , Shaari Khozirah , Siong Hock Ho Anthony , Haji Lajis Nordin , Hwang Teo Soo , Boon Lee Hong
Published: March 2011

In our screening program for new photosensitizers from Malaysian biodiversity for photodynamic therapy (PDT) of cancer, MeOH extracts of ten terrestrial plants from Cameron Highlands in Pahang, Peninsular Malaysia, were tested. In a short‐term 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay, 20 μg/ml each of these extracts were incubated in a pro‐myelocytic leukemia cell‐line, HL60, with or without irradiation with 9.6 J/cm2 of a broad spectrum light. Three samples, Labisia longistyla, Dichroa febrifuga, and Piper penangense, were photocytotoxic by having at least twofold lower cell viability when irradiated compared to the unirradiated assay. The extract of the leaves of Piper penangense, a shrub belonging to the family Piperaceae and widely distributed in the tropical and subtropical regions in the world, was subsequently subjected to bioassay‐guided fractionation using standard chromatography methods. Eight derivatives of pheophorbide‐a and ‐b were identified from the fractions that exhibited strong photocytotoxicity. By spectroscopic analysis, these compounds were identified as pheophorbide‐a methyl ester (1), (R,S)‐132‐hydroxypheophorbide‐a methyl ester (2 and 3), pheophorbide‐b methyl ester (4), 132‐hydroxypheophorbide‐b methyl ester (5), 152‐hydroxylactone pheophorbide‐a methyl ester (6), 152‐methoxylactone pheophorbide‐a methyl ester (7), 152‐methoxylactone pheophorbide‐b methyl ester (8).
Coupling Proteomics and Transcriptomics for the Identification of Novel and Variant Forms of Mollusk Shell Proteins: A Study with P. margaritifera
Authors: Berland Sophie , Marie Arul , Duplat Denis , Milet Christian , Sire Jean Yves , Bédouet Laurent
Published: March 2011

Shell matrix proteins from Pinctada margaritifera were characterized by combining proteomics analysis of shell organic extracts and transcript sequences, both obtained from the shell‐forming cell by using the suppression subtractive hybridization method (SSH) and from an expressed sequence tag (EST) database available from Pinctada maxima mantle tissue. Some of the identified proteins were homologues to proteins reported in other mollusk shells, namely lysine‐rich matrix proteins (KRMPs), shematrins and molluscan prismatic and nacreous layer 88 kDa (MPN88). Sequence comparison within and among Pinctada species pointed to intra‐ and interspecies variations relevant to polymorphism and to evolutionary distance, respectively. In addition, a novel shell matrix protein, linkine was identified. BLAST analysis of the peptide sequences obtained from the shell of P. margaritifera against the EST database revealed the presence of additional proteins: two proteins similar to the Pif97 protein that was identified in the shell of P. fucata, a chitinase‐like protein previously identified in Crassostrea gigas, two chitin‐binding proteins, and two incomplete sequences of proteins unknown so far in mollusk shells. Combining proteomics and transcriptomics analysis we demonstrate that all these proteins, including linkine, are addressed to the shell. Retrieval of motif‐forming sequences, such as chitin‐binding, with functional annotation from several peptides nested in the shell could indicate protein involvement in shell patterning.
Photoinduced Nitric Oxide Release from a Nitrobenzene Derivative in Mitochondria
Authors: Horinouchi Taeko , Nakagawa Hidehiko , Suzuki Takayoshi , Fukuhara Kiyoshi , Miyata Naoki
Published: March 2011

We report a novel NO donor (RpNO), containing a 2,6‐dimethylnitrobenzene moiety for photocontrollable NO release and a rhodamine moiety for targeting to mitochondria. Photorelease of NO from RpNO in aqueous solution was confirmed by means of ESR analysis. Cellular release of NO from RpNO was confirmed with the aid of DAF‐FM DA, an NO‐specific fluorescence probe. RpNO was colocalized with MitoTracker Green FM, a mitochondrial stain, in HCT116 colon cancer cells and exhibited photodependent cytotoxicity. Our results indicate that RpNO is an effective NO donor for time‐controlled, mitochondria‐specific NO treatment.
Self‐Assembly of Chiral trans‐Cyclobutane‐Containing β‐Dipeptides into Ordered Aggregates
Authors: Gorrea Esther , Nolis Pau , Torres Elisabeth , Da Silva Eric , Amabilino David B. , Branchadell Vicenç , Ortuño Rosa M.
Published: March 2011

Two chiral synthetic β‐dipeptides have been constructed, one with two trans‐cyclobutane residues and the other with one trans and one cis fragment, 1 and 2, respectively, and investigated to get insight into the non‐covalent interactions responsible for their self‐assembly to form ordered aggregates, as well into parameters such as their morphology and size. Experimental evidence of the formation of these assemblies was provided by spectroscopy, microscopy and X‐ray diffraction experiments that suggest the formation of nanoscale helical aggregates. This process involves a conformational change in the molecules of each dipeptide with respect to the preferred conformation of the isolated molecules in solution. A high‐resolution NMR spectroscopy study allowed the determination of the dynamics of the gelation process in [D8]toluene and the sol–gel transition temperature, which was around 270 K in this solvent at a concentration of 15 mM. NMR spectroscopy experiments also provided some information about conformational changes involved in the sol–gel transition and also suggested a different gel packing for each dipeptide. These observations have been nicely explained by computational studies. The self‐assembly of the molecules has been modelled and suggested a head‐to‐head molecular arrangement for 1 and a head‐to‐tail arrangement for 2 to give helical structures corresponding to hydrogen‐bonded single chains. These chains interact with one another in an antiparallel way to afford bundles, the significant geometry parameters of which fit well to the main peaks observed in wide‐angle X‐ray diffraction spectra of the aggregates in the solid state.
Selective Synthesis of β‐Alkylpyrroles
Authors: Tsuchimoto Teruhisa
Published: March 2011

β‐Alkylpyrroles are key structural motifs found in many natural products and biologically active compounds as well as functional organic materials. For this reason, synthetic chemists continue to be interested in construction of the framework of β‐alkylpyrroles. Due to sufficient aromaticity and π‐excessive nature of pyrroles, a straightforward approach to β‐alkylpyrroles should be electrophilic aromatic substitution (SEAr) toward the pyrrole ring. However, since a primary nucleophilic site of pyrroles is an α‐position, some “trick” is required to direct incoming alkyl electrophiles toward a β‐position. This Concept article focuses on presenting previous efforts that have been devoted to the synthesis of β‐alkylpyrroles, mainly through the SEAr route.
Addition and Redox Reactivity of Hydrogen Sulfides (H2S/HS−) with Nitroprusside: New Chemistry of Nitrososulfide Ligands
Authors: Quiroga Sandra L. , Almaraz Alejandra E. , Amorebieta Valentín T. , Perissinotti Laura L. , Olabe José A.
Published: March 2011

The nitroprusside ion [Fe(CN)5NO]2− (NP) reacts with excess HS− in the pH range 8.5–12.5, in anaerobic medium (“Gmelin” reaction). The progress of the addition process of HS− into the bound NO+ ligand was monitored by stopped‐flow UV/Vis/EPR and FTIR spectroscopy, mass spectrometry, and chemical analysis. Theoretical calculations were employed for the characterization of the initial adducts and reaction intermediates. The shapes of the absorbance–time curves at 535–575 nm depend on the pH and concentration ratio of the reactants, R=[HS−]/[NP]. The initial adduct [Fe(CN)5N(O)SH]3− (AH, λmax≈570 nm) forms in the course of a reversible process, with kad=190±20 M−1 s−1, k‐ad=0.3±0.05 s−1. Deprotonation of AH (pKa=10.5±0.1, at 25.0 °C, I=1 M), leads to [Fe(CN)5N(O)S]4− (A, λmax=535 nm, ε=6000±300 M−1 cm−1). [Fe(CN)5NO].3− and HS2.2− radicals form through the spontaneous decomposition of AH and A. The minor formation of the [Fe(CN)5NO]3− ion equilibrates with [Fe(CN)4NO]2− through cyanide labilization, and generates the “g=2.03” iron–dinitrosyl, [Fe(NO)2(SH)2]−, which is labile toward NO release. Alternative nucleophilic attack of HS− on AH and A generates the reactive intermediates [Fe(CN)5N(OH)(SH)2]3− and [Fe(CN)5N(OH)(S)(SH)]4−, respectively, which decompose through multielectronic nitrosyl reductions, leading to NH3 and hydrogen disulfide, HS2−. N2O is also produced at pH≥11. Biological relevance relates to the role of NO, NO−, and other bound intermediates, eventually able to be released to the medium and rapidly trapped by substrates. Structure and reactivity comparisons of the new nitrososulfide ligands with free and bound nitrosothiolates are provided.
Catalytic Self‐Assembled Monolayers on Au Nanoparticles: The Source of Catalysis of a Transphosphorylation Reaction
Authors: Zaupa Giovanni , Mora Claudia , Bonomi Renato , Prins Leonard J. , Scrimin Paolo
Published: March 2011

The catalytic activity of a series of Au monolayer protected colloids (Au MPCs) containing different ratios of the catalytic unit triazacyclononane⋅ZnII (TACN⋅ZnII) and an inert triethyleneglycol (TEG) unit was measured. The catalytic self‐assembled monolayers (SAMs) are highly efficient in the transphosphorylation of 2‐hydroxy propyl 4‐nitrophenyl phosphate (HPNPP), an RNA model substrate, exhibiting maximum values for the Michaelis–Menten parameters kcat and KM of 6.7×10−3 s−1 and 3.1×10−4 M, respectively, normalized per catalytic unit. Despite the structural simplicity of the catalytic units, this renders these nanoparticles among the most active catalysts known for this substrate. Both kcat and KM parameters were determined as a function of the mole fraction of catalytic unit (x1) in the SAM. Within this nanoparticle (NP) series, kcat increases up till x1≈0.4, after which it remains constant and KM decreases exponentially over the range studied. A theoretical analysis demonstrated that these trends are an intrinsic property of catalytic SAMs, in which catalysis originates from the cooperative effect between two neighboring catalytic units. The multivalency of the system causes an increase of the number of potential dimeric catalytic sites composed of two catalytic units as a function of the x1, which causes an apparent increase in binding affinity (decrease in KM). Simultaneously, the kcat value is determined by the number of substrate molecules bound at saturation. For values of x1>0.4, isolated catalytic units are no longer present and all catalytic units are involved in catalysis at saturation. Importantly, the observed trends are indicative of a random distribution of the thiols in the SAM. As indicated by the theoretical analysis, and confirmed by a control experiment, in case of clustering both kcat and KM values remain constant over the entire range of x1.
Syntheses and X‐ray Crystal Structures of Organoantimony Diazides
Authors: Lyhs Benjamin , Bläser Dieter , Wölper Christoph , Schulz Stephan
Published: March 2011

Antimony(III) complexes of the general type LSbF2 (3: L1=[tBuC(NiPr)2]; 4: L2=[tBuC(NDipp)2], Dipp=2,6‐iPr2C6H3) and LSb(N3)2 (6: L1; 7: L2) were prepared in high yields and characterized by elemental analyses, NMR and IR spectroscopy and single‐crystal X‐ray diffraction. Moreover, the solid‐state structures of [L2SbF2][L2Li] (5), [L2AlH2] (1), and [L′H][L′K(thf)3] (2; L′=HC(NDipp)2) are described, in which the Li (5) and K atoms (2) adopt rather unusual coordination modes.