bluuebunny/crossref_metadata_2025 huggingface dataset:
The constrictor dorsalis musculature and basipterygoid articulation inSphenodon
Authors: Johnston Peter
Published: October 2009

The constrictor internus dorsalis (CID) trigeminal muscles in vertebrates lie between the braincase and the palatoquadrate bar, and in reptiles they are believed to function in the relative movements between braincase and maxillary segment known as kinesis. In amniote taxa, the presence of a synovial basipterygoid articulation (BPA) correlates with presence of the CID. Previous descriptions of the CID in the tuataraSphenodon(Rhynchocephalia) are inconsistent regarding presence, size and direction, particularly of the m. protractor pterygoidei. TheSphenodonskull is reported to be akinetic. The CID was investigated inSphenodonby examination of sectioned embryonic and hatchling material, and by dissection of fixed specimens. Osteological correlates of CID muscles and morphology of the BPA were examined on disarticulated skulls and on CT scan images. The vectors of action of these muscles in relation to the BPA were projected onto CT images. Mm. levator bulbi and levator pterygoidei are found to be similar to most previous descriptions, but m. protractor pterygoidei was found in a different position, lying entirely medial to the palatoquadrate bar. The insertions of mm. levator pterygoidei and protractor pterygoidei are visible on the disarticulated pterygoid bone. The BPA is mobile only by rotation around the horizontal axis of the joints themselves; metakinesis is not possible in theSphenodonskull. M. protractor pterygoidei appears to either resist or recognize lateral displacement of the BPA. M. levator ptergyoidei is placed to resist dorsal displacement of the braincase at the BPA, or torsion of the braincase around its longitudinal axis. The BPA appears to be a means to direct compressive stress via the base of the braincase and occipital condyle to the cervical spine inSphenodon, and probably in its direct ancestors. Metakinesis may never have been a feature of the lepidosaur skull. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.
A framework of intellectual capital management based on ISO 9001 quality management system: The case study of ISO 9001 certified public R&D institute
Authors: Kim Dong‐young , Kumar Vinod , Kumar Uma
Published: October 2009

The purpose of this paper is to present a framework for an effective implementation of intellectual capital (IC) management. The framework is primarily established based on the ISO 9001 quality management system that is an international representative process management approach. Based on the case study of an ISO 9001 certified public in Research and Development (R&D) organization, this study concludes that: (1) the framework helps organizations to identify customers' needs as well as to evaluate customers' perception about the organizations' efforts; (2) various requirements of the framework play a crucial role in building a foundation to continually develop the framework; (3) the framework can encourage ISO 9001 certified organizations to implement IC management by providing similar principles and methodologies. Copyright © 2009 John Wiley & Sons, Ltd.
A contemporary review of balance dysfunction following vestibular schwannoma surgery
Authors: Saman Yougan , Bamiou Doris‐Eva , Gleeson Michael
Published: October 2009

Objectives/Hypothesis:

This review aims to evaluate the literature pertaining to subjective balance dysfunction following vestibular schwannoma surgery; the effect of postoperative imbalance on disability, handicap and quality of life; and to determine factors that influence vestibular compensation.

Methods:

Ovid MEDLINE, Cochrane databases, and relevant contemporary texts were searched for papers relating to subjective balance dysfunction following vestibular schwannoma surgery. The quality of this clinical evidence was evaluated.

Results:

The search yielded 26 studies assessing subjective balance dysfunction following vestibular schwannoma surgery. Analysis revealed that the majority of patients complain of balance dysfunction following surgery; however, a small number report disability or handicap. A few studies have demonstrated a decreased quality of life due to balance dysfunction. Factors have been identified that may contribute to a poor recovery.

Conclusions:

Further study is needed of the factors that influence vestibular compensation following vestibular schwannoma surgery. This will help to counsel patients prior to surgery and develop strategies for rehabilitation. Laryngoscope, 2009
A lower bound for the symbolic multifractal spectrum of a self‐similar multifractal with arbitrary overlaps
Authors: Olsen L.
Published: October 2009

By now the multifractal structure of self‐similar measures satisfying the so‐called Open Set Condition is well understood. However, if the Open Set Condition is not satisfied, then almost nothing is known. In this paper we prove a nontrivial lower bound for the symbolic multifractal spectrum of an arbitrary self‐similar measure. We emphasize that we are considering arbitrary self‐similar measures (and sets) which are not assumed to satisfy the Open Set Condition or similar separation conditions. Our results also have applications to self‐similar sets which do not satisfy the Open Set Condition (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An expansive multiplier property for operator‐valued Bergman inner functions
Authors: Olofsson Anders
Published: October 2009

We show that operator‐valued Bergman inner functions have the so‐called expansive multiplier property generalizing a well‐known result of Hedenmalm in the scalar case. This analysis leads to norm bounds for input output maps for a related class of discrete time linear systems. The proof uses properties of the biharmonic Green function (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local smoothing for Kato potentials in three dimensions
Authors: Barceló J. A. , Bennett J.M. , Ruiz A. , Vilela M. C.
Published: October 2009

We prove weighted local smoothing estimates for the resolvent of the Laplacian in three dimensions with weights belonging to the Kerman–Sawyer class. This class contains the well‐known global Kato and Rollnik classes. We go on to discuss dispersive and Strichartz estimates for perturbations of the Laplacian by small potentials, and apply our results and observations to the well‐posedness in L2 of the Cauchy problem for some linear and semilinear Schrödinger equations (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A semiorthogonal decomposition for Brauer–Severi schemes
Authors: Bernardara Marcello
Published: October 2009

A semiorthogonal decomposition for the bounded derived category of coherent sheaves on a Brauer–Severi scheme is given. It relies on bounded derived categories of suitably twisted coherent sheaves on the base (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Coates–Sinnott Conjecture
Authors: Popescu Cristian D.
Published: October 2009

In [5], Coates and Sinnott formulated a far reaching conjecture linking the values ΘF/k,S (1 — n) for even integers n ≥ 2 of an S ‐imprimitive, Galois‐equivariant L ‐function ΘF/k,S associated to an abelian extension F/k of totally real number fields to the annihilators over the group ring ℤ[G (F/k)] of the even Quillen K ‐groups K2n–2 (OF) associated to the ring of integers OF of the top field F. In the same paper, Coates and Sinnott essentially prove the 𝓁 ‐adic étale cohomological version of their conjecture, in which K2n–2(OF) is replaced by H2 et (OF [1/𝓁 ], ℤ(n)), for all primes 𝓁 > 2, under the hypothesis that k = ℚ. Refinements of this result for k = ℚ, involving Fitting ideals rather than annihilators of H2et (OF [1/𝓁], ℤ𝓁(n)), were obtained in particular cases by Cornacchia–Østvaer [7] and in general by Kurihara [14]. More recently, Burns and Greither [3] proved the same type of refinements (involving Fitting ideals of étale cohomology groups) for arbitrary totally real base fields k, but working under the very strong hypothesis that the Iwasawa μ ‐invariants μF,𝓁 vanish for all odd primes 𝓁. In this paper, we study a class of abelian extensions of an arbitrary totally real base field k including, for example, subextensions of real cyclotomic extensions of type k (ζ)+/k, where p is an odd prime. For this class of extensions, we prove similar refinements of the étale cohomological version of the Coates–Sinnott conjecture, under no vanishing hypotheses for the Iwasawa μ‐invariants in question. Our methods of proof are different from the ones employed in [3], [14] and [7]. We build upon ideas developed by Greither in [10] and Wiles in [23] and [22], in the context of Brumer's Conjecture. If the Quillen–Lichtenbaum Conjecture is proved (and a proof seems tobe within reach), then we have canonical ℤ𝓁[G (F/k)]‐module isomorphisms
equation image
for all n ≥ 2, all i = 1,2, and all primes 𝓁 > 2, and all these results will yield proofs of the original K ‐theoretic version of the Coates–Sinnott Conjecture, in the cases and under the various hypotheses mentioned above (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On positive invertibility of operators and their decompositions
Authors: Weber M. R.
Published: October 2009

In Banach spaces ordered by a normal cone that contains interior points the positive invertibility of operators is studied. If there exists a uniformly positive functional then any positively invertible operator A possesses a B ‐decomposition, i.e., a positive decomposition A = U – V with the properties: U–1 exists, VU–1 ≥ 0, Ax ≥ 0, U x ≥ 0 imply x ≥ 0 and r (VU–1) < 1. Earlier it was shown that the existence of a B ‐decomposition with r (VU–1) < 1 is sufficient for the positive invertibility of the operator A. Peris' result is obtained as a special case of the main theorem. The decomposition is demonstrated for a positively invertible operator in a Banach space ordered by an ice cream cone (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Derivatives of 1,1‐Diamino‐2,2‐dinitroethene (DADNE) and Specific Reactivity Understanding
Authors: Hervé Grégoire
Published: October 2009

Some further reactions on 1,1‐diamino‐2,2‐dinitroethene (DADNE) were performed in view of a better reactivity understanding. This paper intends to give a global overview of the specific reactivity of DADNE dealing with kinetics, mechanism and structure–reactivity relationship. A general and updated scheme on the specific reactivity of DADNE was subsequently suggested.
Progress of the EPOS project: Gamma‐induced Positron Spectroscopy (GiPS)
Authors: Krause‐Rehberg Reinhard , Anwand Wolfgang , Brauer Gerhard , Butterling Maik , Cowan Tom , Hartmann Andreas , Jungmann Marco , Krille Arnold , Schwengner Ronald , Wagner Andreas
Published: October 2009

Gamma‐induced positron generation has been performed using the superconducting electron accelerator ELBE at the Research Centre Dresden‐Rossendorf (Germany). It has an intense, pulsed (26 MHz) gamma source (bremsstrahlung). This source has been used to accomplish positron annihilation spectroscopy for different materials (Fe, silica, water). Since the gamma bunches are very short (<5 ps) the facility is suitable for positron lifetime spectroscopy using the accelerator bunching pulse for timing. The application of coincident measurements (AMOC, CDBS) reduces sufficiently the background of scattered gammas to obtain high‐quality spectra. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microstructural study of supported liquid membranes using slow positron beam
Authors: Pujari P. K. , Maheshwari P. , Sharma S. K. , Dutta D. , Sudarshan K. , Reddy A. V. R.
Published: October 2009

Pore architecture in four supported liquid membranes (PTFE membranes) has been investigated using beam based positron annihilation spectroscopy (PAS) with variable positron energy (0.2‐10 keV). Formation of positronium (Ps), its diffusion, re‐emission and annihilation at various depths of the membranes have been investigated. It was observed that o‐Ps 3γ/2γ annihilation ratio is a sensitive method to study the pore architecture. The 3γ/2γ curves are utilized to calculate diffusion length of o‐Ps in the membranes. The o‐Ps diffusion length measures the mobility of o‐Ps in the membranes and represents pore interconnectivity, which in turn point to the tortuosity of the membrane. The relative open porosity in the membranes is measured by studying the 3γ/2γ profiles in the membranes capped with thin gold layer. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Order‐disorder transitions in self‐assembled polymers: A positron annihilation study
Authors: Ramani Ramasubbu , Valkama Sami , Kilpeläinen Simo , Tumisto Filip , Brinke Gerrit ten , Ruokolainen Janne , Alam Sarfaraz , Ikkala Olli
Published: October 2009

We report here the first results of order‐disorder transition (ODT) in a self‐assembled comb‐like polymer‐amphiphile supramolecular system as identified from the change in positron lifetime parameters. We have used poly(4‐vinyl pyridine) hydrogen bonded with 3‐pentadecyl phenol, which upon heating showed a stepwise reduction in o ‐Ps intensity at the ODT from lamellar self‐assembled state to the disordered state. The ODT temperature was confirmed by differential scanning calorimetry and small angle X‐ray scattering. The free volume “holes” in this polymer‐amphiphile system are proposed to be near the chain ends of the polymer backbones. We suggest that positron lifetime spectroscopy can serve as a technique to identify ODTs in self‐assembled lamellar structured supramolecular systems. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
PAL spectroscopy and testing for potential carcinogens
Authors: Byakov Vsevolod M. , Stepanov Sergey V. , Stepanova Olga P.
Published: October 2009

Chemical carcinogens are often strong electrophiles. The variation of the Ps formation probability versus concentration of the substance being tested in a solvent (modelling intracellular milieu) may serve as an indicator of carcinogenic properties of the solute. Being effectivescavengers of track electrons such chemicals strongly inhibit Ps formation.

Tests carried out with a number of well‐known chemical compounds indicate this expectation and indicate the possibility of using PAL spectroscopy in the search for carcinogenic and anticarcinogenic agents. It is further shown that carcinogenic activity of macro‐samples seemto correlate well with their work function. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of ZnO nanostructures: A challenge to positron annihilation spectroscopy and other methods
Authors: Brauer Gerhard , Anwand Wolfgang , Grambole Dieter , Egger Werner , Sperr Peter , Beinik Igor , Wang Lin , Teichert Christian , Kuriplach Jan , Lang Jan , Zviagin Sergei , Cizmar Erik , Ling Chi Chung , Hsu Yuk Fan , Xi Yan Yan , Chen Xinyi , Djurišić Aleksandra B. , Skorupa Wolfgang
Published: October 2009

ZnO nanostructures are of special interest for device applications. However, their structural characterization remains an ongoing challenge. This paper reviews recent efforts and latest achievements in this direction. Results comprise PAS in the form of Slow Positron Implantation Spectroscopy (SPIS) and Pulsed Low Energy Positron Lifetime Spectroscopy (PLEPS), Nuclear Reaction Analysis (NRA), Atomic Force Microscopy (AFM), conductive AFM (C‐AFM), Nuclear Magnetic Resonance (NMR), Electron Spin Resonance (ESR), Photoluminescence (PL) spectroscopy, and latest theoretical investigations of structure‐related and positron properties of selected defects. The fundamental importance of a relationship between fabrication conditions, native defect formation, and resulting optical and electronic properties is demonstrated by getting either inferior (nanorods) or significantly improved (tetrapods) optical properties compared to single crystal samples, depending on the nanostructure fabrication method. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positronium chemistry of the Ps quenchers adsorbed on to the mesoporous resin
Authors: Sudarshan K. , Patil P. N. , Goswami A. , Pillai K. T. , Pujari P. K.
Published: October 2009

The positron annihilation lifetime studies were carried out on XAD‐4 resin loaded with different Ps quenchers in sub‐monolayer quantities. The o‐Ps intensity and lifetime of the longest lived component, corresponding to positronium annihilation in mesopores, were seen to reduce with adsorption of β‐naphthol. In the case of nitroaniline and nitrobenzene adsorption, only the intensity of this component reduced. The studies showed that the physical dimension of the quencher should also be large to manifest as positronium quencher when adsorbed on to the porous materials if the porous material has large surface fractals. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of iron phthalocyanine organic semiconductor thin films using slow positron beam
Authors: Maheshwari P. , Dutta D. , Samanta S. , Singh A. , Aswal D. K. , Reddy A. V. R. , Pujari P. K.
Published: October 2009

Iron phthalocyanine (FePc) thin films grown by molecular beam epitaxy have been studied using slow positron beam and atomic force microscopy (AFM) techniques. A correlation between microstructure investigated using these two techniques as a function of film thickness (50‐140 nm) and crystallinity (amorphous and crystalline) is examined. Doppler broadening measurements revealed higher S‐parameter in amorphous film indicating more defects as compared to crystalline film. For crystalline films, as the thickness increases the S‐parameter increases, indicating the defect densities (free volume for positron annihilation) increases. However, AFM studies show that thinner film has columnar grains that transform to granular form with increase in thickness. The former shows wider grain boundaries which can not be sensed by positron. On the other hand, it reveals that columnar grains are more orderly arranged with small free volume inside the grain. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron annihilation studies of HPT deformed aluminium alloys
Authors: Lechner Wolfgang , Puff Werner , Würschum Roland , Wilde Gerhard , Zehetbauer Michael J. , Pippan Reinhard
Published: October 2009

Positron lifetime and 2‐dimensional Doppler broadening measurements were used to study the influence of high pressure torsion (HPT) on the precipitation in Al‐Cu‐Mg alloys. The combination of the two experimental methods enables a specific and chemical sensitive distinction between interfacial vacancy‐type defects associated with precipitates and the vacancy‐type lattice defects formed upon high pressure torsion. Different aging behaviour is observed for undeformed and HPT‐deformed samples. In the Sm‐doped aluminium different defects depending on the pre‐treatment could be clearly identified. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Detecting thermal defects in age hardening Al‐6063 alloys by positron annihilation Doppler broadening technique
Authors: Abdel‐Rahman M.
Published: October 2009

The Doppler broadening of positron annihilation radiation lineshape technique has been applied to study the effect of quenching on the behavior of the lineshape‐ parameters S and W, in a set of age‐hardened Al‐6063 wrought alloys. An abrupt increase in the S‐parameter associated with abrupt decrease in the W‐parameter was obtained at a quenching temperature of 433 K due to precipitation formation. S‐parameter was used to determine the trapping rate and grain size of the alloy for different quenching temperatures. Trapping rate and grain size of about 7x10+10 sec–1 and 1250 Å, respectively, were obtained at 598 K quenching temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron studies of defects in palladium containing hydrogen
Authors: Troev T. , Staikov P. , Popov E. , Nankov N. , Sato K. , Yoshiie T.
Published: October 2009

Positron lifetime quantum‐mechanical calculations were carried out for investigation of Pd defects containing hydrogen atoms. The electron and positron wave functions have been obtained in the local density approximation to the two component density functional theory. Calculations were done for mono‐vacancy, vacancy‐clusters and vacancy clusters containing hydrogen. The positron trapping is reflected by a lowered annihilation rate, due to the lower electron density. It is found that hydrogen in larger three‐dimensional vacancy clusters change the annihilation characteristics drastically. The lattice relaxation of atoms around vacancy reduces the effective vacancy volume and decrease the positron lifetime at a vacancy. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the cure temperature and the accelerator content on the free volume in a DGEBA epoxy‐anhydride‐imidazole system
Authors: Tognana Sebastián , Salgueiro Walter , Somoza Alberto
Published: October 2009

A PALS study on an epoxy‐anhydride system cured in presence of the accelerator imidazole was carried out. The rate of the curing reaction was changed, modifying in this way the final structure of the samples. Specifically, the parameters cure temperature and accelerator content were modified. From the calorimetric scans, the glass transition temperature of each sample was determined. The results obtained using both techniques are jointly discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the study of liquid crystalline materials using positron annihilation spectroscopy
Authors: Singh K. Chandramani
Published: October 2009

Positron annihilation spectroscopy (PAS) has emerged as a powerful technique for investigating structural changes, phase transformations and micro environmental transformations in a variety of systems. Positron lifetime technique has been employed to investigate various liquid crystalline materials, both thermotropic and lyotropic. Investigations in thermotropic liquid crystalline materials, besides detection of various phase transformations, have revealed solid crystalline polymorphism in some systems. In some thermotropic liquid crystalline materials, the ortho‐positronium (o‐Ps) pick‐off lifetime shows changes which strongly support (i) retention of some memory of more ordered solid phases on passing to the liquid crystalline phase, (ii) strong tendency for the molecules in the mesophases to undergo anti‐parallel bimolecular association, and (iii) the formation of cybotactic groups in a nematic medium. The present paper illustrates some of these features. A work on supercooled states has demonstrated the possibility of using PAS for studying various intra‐ and inter‐molecular motions associated with the molecules of liquid crystalline materials. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The SOP model of change as a new way of looking at causality
Authors: Glassop Linda Irene
Published: October 2009

This research note sets out a multi‐faceted view of causality referred to as the structure‐organization‐process (SOP) model of change. The SOP model is an ontological schema that can be utilized wherever order can be found. A case study on the periodic table and the structure of DNA provide the first insight that the model might be a general organizing principle. More case studies are required to evaluate the applicability of the SOP model. Copyright © 2009 John Wiley & Sons, Ltd.
Mobility and handoff management in vehicular networks: a survey
Authors: Zhu Kun , Niyato Dusit , Wang Ping , Hossain Ekram , In Kim Dong
Published: October 2009

Mobility management is one of the most challenging research issues for vehicular networks to support a variety of intelligent transportation system (ITS) applications. The traditional mobility management schemes for Internet and mobilead hocnetwork (MANET) cannot meet the requirements of vehicular networks, and the performance degrades severely due to the unique characteristics of vehicular networks (e.g., high mobility). Therefore, mobility management solutions developed specifically for vehicular networks would be required. This paper presents a comprehensive survey on mobility management for vehicular networks. First, the requirements of mobility management for vehicular networks are identified. Then, classified based on two communication scenarios in vehicular networks, namely, vehicle‐to‐vehicle (V2V) and vehicle‐to‐infrastructure (V2I) communications, the existing mobility management schemes are reviewed. The differences between host‐based and network‐based mobility management are discussed. To this end, several open research issues in mobility management for vehicular networks are outlined. Copyright © 2009 John Wiley & Sons, Ltd.
Security analysis and improvements of IEEE standard 802.16 in next generation wireless metropolitan access network
Authors: Xiong Naixue , Yang Fan , Li Hong‐Yan , Park Jong Hyuk , Dai Yuanshun , Pan Yi
Published: October 2009

Next generation communications (NGC) represents advanced communication environments featuring objects that are focused on users. It is crucial to protect information and digital forensics for NGC. In this paper, we aim to address network security for NGC, including IEEE standard 802.16 that are associated with NGC utilization.

The IEEE standard 802.16 is a wireless air interface technology in Wireless Metropolitan Access Network (WMAN). Now in the new era of wireless networking, it is the solution for ‘last mile’ problem. Point‐to‐MultiPoint (PMP) network architecture network mode and mesh network mode are two optional networking modes proposed in this standard. However, the security problems in its original protocol may be becoming the most serious obstacle in its marketable producing process. In this paper, explanation and analysis of the security mechanism are based on PMP and mesh networking modes, respectively. This paper focuses on authentication & authorization, which is the most important part but not explicitly defined in original security design of IEEE standard 802.16. Two improved schemes focused on authentication & authorization based on the two modes are proposed to strengthen 802.16 WMAN security, respectively. The relevant analysis and simulation results prove that our schemes are effective. Copyright © 2009 John Wiley & Sons, Ltd.
Quinoline‐n‐butylcyanoacrylate‐based nanoparticles for brain targeting for the diagnosis of Alzheimer's disease
Authors: Kulkarni Padmakar V. , Roney Celeste A. , Antich Peter P. , Bonte Frederick J. , Raghu Anjanapura V. , Aminabhavi Tejraj M.
Published: October 2009

A survey of research activity on nanoparticles (NPs) based on polymeric devices that could cross the blood–brain barrier (BBB) is given along with the presentation of our own data on the development of NPs of n‐butyl‐2‐cyanoacrylate (BCA) for brain delivery to aid the early diagnosis of Alzeimer's disease (AD), a neurodegenerative disorder of the elderly people, the most prevalent form of dementia. Typical data are presented on in vivo detection of amyloid peptides (Aβ) (amyloid plaques) that are used as targets for developing the biological markers for the diagnosis of AD. In order to develop efficient in vivo probes, polymeric n‐butyl‐2‐cyanoacrylate (PBCA) NPs have been prepared and encapsulated with the radio‐labeled amyloid affinity drug 125I‐clioquinol (CQ, 5‐chloro‐7‐iodo‐8‐hydroxyquinoline) to improve the transport to brain and amyloid plaque retention of 125I‐CQ using the NPs of PBCA. The 125I‐CQ discriminately binds to the AD post‐mortem brain tissue homogenates versus control. 125I‐CQ‐PBCA NPs labeled the Aβ plaques from the AD human post‐mortem frontal cortical sections on paraffin‐fixed slides. Storage phosphor imaging verified preferential uptake by AD brain sections compared to cortical control sections. The 125I‐CQ‐PBCA NPs crossed the BBB in wild type mouse, giving an increased brain uptake measured in terms of % ID/g i.e., injected dose compared to 125I‐CQ. Brain retention of 125I‐CQ‐PBCA NPs was significantly increased in the AD transgenic mice (APP/PS1) and in mice injected with aggregated Aβ42 peptide versus age‐matched wild type controls. The results of this study are verified by in vivo storage phosphor imaging and validated by histopathological staining of plaques and select metal ions, viz. Fe2+ and Cu2+. The 125I‐CQ‐PBCA NPs had more efficient brain entry and rapid clearance in normal mice and enhanced the retention in AD mouse brain demonstrating the ideal in vivo imaging characteristics. The 125I‐CQ‐PBCA NPs exhibited specificity for Aβ plaques both in vitro and in vivo. This combination offered radio‐iodinated CQ‐PBCA NPs as the promising delivery vehicle for in vivo single photon emission tomography (SPECT) (123I) or PET (124I) amyloid imaging agent. The importance of the topic in relation to brain delivery and other similar type of work published in this area are covered to highlight the importance of this research to medical disciplines. WIREs Nanomed Nanobiotechnol 2010 2 35–47

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease
Complex mathematical models of biology at the nanoscale
Authors: Bewick Sharon , Yang Ruoting , Zhang Mingjun
Published: October 2009

Mathematical modeling of nanobiosystems is an exciting and rapidly growing new field of research that offers the potential to guide and improve technological developments in both nanomedicine and nanobiomaterial science. Unlike the more traditional fields of science and engineering, however, models of nanobiosystems are notoriously complex. In this paper, we highlight some of the primary sources of complexity in nanobiosystems. In particular, we focus on complexity that arises from the inherent nonlinearity of natural systems, noise generated by low copy numbers of relevant biological constituents, heterogeneity that stems from structure in physical systems at the nanoscale, strong coupling between processes that occur at different scales, and the large dimensions necessary to represent typical biological systems. We then suggest how different mathematical modeling techniques are currently being explored and developed to deal with the complicated and computationally demanding problems that can arise when modeling nanobiosystems. Although a relatively new field, mathematical descriptions of nanobiology are becoming increasingly more common and more important for both directing and interpreting experimental studies on nanobiosystems. The goal of this review is to emphasize the challenges associated with modeling nanobiosystems to inspire renewed effort in this highly interdisciplinary, but certainly rewarding, field. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Surgical treatment of hilar cholangiocarcinoma in the “new era”: the Nagoya University experience
Authors: Igami Tsuyoshi , Nishio Hideki , Ebata Tomoki , Yokoyama Yukihiro , Sugawara Gen , Nimura Yuji , Nagino Masato
Published: October 2009

Objective

To review our surgical experience with hilar cholangiocarcinoma in the “new era.”

Methods

The medical records of 428 patients with hilar cholangiocarcinoma who underwent treatment between 2001 and 2008 at the First Department of Surgery, the Nagoya University Hospital, were retrospectively reviewed.

Results

Of the 428 patients, 298 (70%) underwent surgical resection (R0,n = 220; R1,n = 70; R2,n = 8). Portal vein resection was performed in 111 (37%) patients, and hepatic artery resection was performed in 53 (18%) patients. Several different types of postoperative complications occurred in a total of 129 (43%) patients and led to 6 (2%) deaths. Of the 298 resected tumors, 206 (69%) were extrahepatic type tumors, and the remaining 92 (31%) were intrahepatic type tumors. Using the Bismuth classification criteria, we identified 15 (5%) type I, 21 (7%) type II, 120 (40%) type III, and 142 (48%) type IV tumors. The overall 1‐, 3‐, and 5‐year survival rates for all 298 patients were 77, 49, and 42%, respectively. The survival rates were highest among the 197 patients with pM0 disease who underwent R0 resection. Patients in this subgroup had a 5‐year survival rate of 52%. The 5‐year overall survival rate for the 55 patients with pM0 disease who underwent R1 resection was 32%. The survival rate for patients who had pM1 disease and/or underwent R2 resection was the worst of all the subgroups, but was nonetheless significantly better than that of patients with unresectable tumors. The survival rate for patients who underwent vascular resection and reconstruction was unexpectedly better, with 5‐year survival of >20%.

Conclusions

The surgical approach to hilar cholangiocarcinoma has become more challenging in the new era. Nevertheless, surgical outcomes have been improved, with decreased morbidity and mortality rates being observed. Long‐term survival has also steadily improved. These findings indicate that biliary surgeons should use an aggressive surgical strategy to treat this intractable disease.
Nanoparticles of Block Ionomer Complexes from Double Hydrophilic Poly(acrylic acid)-b-poly(ethylene oxide)-b-poly(acrylic acid) Triblock Copolymer and Oppositely Charged Surfactant
Authors: Peng Zhiping , Sun Yuelong , Liu Xinxing , Tong Zhen
Published: October 2009

The novel water-dispersible nanoparticles from the double hydrophilic poly(acrylic acid)-b-poly(ethylene oxide)-b-poly(acrylic acid) (PAA-b-PEO-b-PAA) triblock copolymer and oppositely charged surfactant dodecyltrimethyl ammonium bromide (DTAB) were prepared by mixing the individual aqueous solutions. The structure of the nanoparticles was investigated as a function of the degree of neutralization (DN) by turbidimetry, dynamic light scattering (DSL),ζ-potential measurement, and atomic force microscope (AFM). The neutralization of the anionic PAA blocks with cationic DTAB accompanied with the hydrophobic interaction of alkyl tails of DTAB led to formation of core–shell nanoparticles with the core of the DTAB neutralized PAA blocks and the shell of the looped PEO blocks. The water-dispersible nanoparticles with negative ζ-potential were obtained over the DN range from 0.4 to 2.0 and their sizes depended on the DN. The looped PEO blocks hindered the further neutralization of the PAA blocks with cationic DTAB, resulting in existence of some negative charged PAA-b-PEO-b-PAA backbones even when DN > 1.0. The spherical and ellipsoidal nature of these nanoparticles was observed with AFM.
Imaging on pelvic pyomyositis in children related to pathogenesis
Authors: Gonzalez Moran Gaspar , Garcia Duran Cristina , Albiñana Javier
Published: October 2009

Purpose

Pelvic pyomyositis in children is a rare infectious condition, although it is increasingly reported in temperate climates. Often considered a primary disease, new diagnostic methods are able to identify additional foci of infection. The purpose of this study is to review our patients and to analyze the imaging studies to determine its pathogenesis.

Methods

A retrospective study of the clinical charts and imaging records of 11 patients was made, noting the number and location of muscles involved, as well as bone and joint involvement.

Results

Besides the classical form of pelvic pyomyositis, i.e., iliopsoas pyomyositis, other muscular groups were frequently affected, often with multiple involvement. Bone involvement is also frequent. Magnetic resonance imaging (MRI) gives the most useful information.

Conclusion

MRI is the diagnostic procedure of choice for diagnosing pelvic pyomyositis in children. It may also have an elucidating role in the debated pathogenesis of this condition. In most of the cases, pelvic pyomyositis in children could be secondary.
Les théoriciens italiens de la raison d'État Carrières et motivations
Authors: Cremer Albert
Published: October 2009

L’article cherche à mettre en lumière les carrières et les motivations des auteurs italiens qui ont écrit sur la raison d’État entre 1550 et 1650. La moitié d’entre eux furent des ecclésiastiques aux positions très différentes auxquels se joignaient juristes, médecins et gens de lettres. Nombre d’ecclésiastiques enseignaient dans les universités et tentaient d’obtenir un poste de secrétaire ou de conseiller à la cour, auprès d’un prince ou d’un cardinal. D’autres motifs les poussaient à rédiger leurs traités: la réprobation des idées de Machiavel, l’ouverture d’espaces d’action pour le prince, mais aussi la défense des libertés républicaines. Ces traités et recueils de maximes proposent surtout un savoir littéraire. Leur influence sur la rationalisation de l’État est ici analysée de manière sceptique.
Libertés et sûreté: les mutations de l'État de droit
Authors: Delmas-Marty Mireille
Published: October 2009

Le droit à la sûreté soumet l’État au droit tout en pouvant légitimer des atteintes aux libertés, apparemment contraires à l’État de droit. On propose d’analyser ici les mutations de l’État de droit, notamment depuis la pérennisation de l’état d’exception après 2001 et l’apparition de régimes de suspicion, comme l’expression de trois processus juridiques distincts de suspension, de contournement et de détournement. Il s’agit aussi de rappeler comment, au-delà de la distinction entre politique autoritaire et libérale, un double mouvement, interne et international, de constitutionnalisation et d’internationalisation des systèmes de droit, constitue un ferment de résistance, limité mais déjà effectif, à toute raison d’État.
Il mito della Stoto modemo nella fortuna della ragion di Stato
Authors: Dini Vittorio
Published: October 2009

La trattatistica della ragion di Stato ha contribuito a superare il modello ideale dello stato platonico, il modello naturalistico aristotelico, il modello del diritto naturale teologico della« respublica christiana ». Insieme al machiavellismo ha conquistato la moderna distinzione tra politica e morale, ha prodotto una realistica pedagogia dell’arte di governare. Costituisce un contributo essenziale all’elaborazione del mito dello Stato moderno, con i suoi caratteri di universalità realmente operante nel disciplinamento sociale e individuale, ma anche con i limiti e le contraddizioni che neppure la forma del mito riesce a nascondere: crisi e guerra (civile e tra le nazioni).
Little Ice Age fluctuations of Glaciar Río Manso in the North Patagonian Andes of Argentina
Authors: Masiokas M.H. , Luckman B.H. , Villalba R. , Ripalta A. , Rabassa J.
Published: October 2009

Little Ice Age (LIA) fluctuations of Glaciar R"o Manso, north Patagonian Andes, Argentina are studied using information from previous work and dendrogeomorphological analyses of living and subfossil wood. The most extensive LIA expansion occurred between the late 1700s and the 1830"1840s. Except for a massive older frontal moraine system apparently predating ca. 2240 14C yr BP and a small section of a south lateral moraine ridge that is at least 300 yr old, the early nineteenth century advance overrode surficial evidence of any earlier LIA glacier events. Over the past 150 yr the gently sloping, heavily debris-covered lower glacier tongue has thinned significantly, but several short periods of readvance or stasis have been identified and tree-ring dated to the mid-1870s, 1890s, 1900s, 1920s, 1950s, and the mid-1970s. Ice mass loss has increased in recent years due to calving into a rapidly growing proglacial lake. The neighboring debris-free and land-based Glaciar Fr"as has also retreated markedly in recent years but shows substantial differences in the timing of the peak LIA advance (early 1600s). This indicates that site-specific factors can have a significant impact on the resulting glacier records and should thus be considered carefully in the development and assessment of regional glacier chronologies.
ON m-COVERS AND m-SYSTEMS
Authors: SUN ZHI-WEI
Published: October 2009

Let 𝒜={as(mod ns)}ks=0 be a system of residue classes. With the help of cyclotomic fields we obtain a theorem which unifies several previously known results related to the covering multiplicity of 𝒜. In particular, we show that if every integer lies in more than m0=⌊∑ ks=11/ns⌋ members of 𝒜, then for any a=0,1,2,… there are at least ${m_0\choose \lfloor a/n_0\rfloor }$ subsets I of {1,…,k} with ∑ s∈I1/ns=a/n0. We also characterize when any integer lies in at most m members of 𝒜, where m is a fixed positive integer.
Caledonian strike-slip terrane accretion in W. Ireland: insights from very low-grade metamorphism (illite–chlorite crystallinity and b0parameter)
Authors: RICE A. H. N. , WILLIAMS D. M.
Published: October 2009

Analysis of pelites with detrital white-micas in the Clew Bay–Galway Bay segment of the Irish Caledonides indicates that b0data from whole-rock and < 2 μm fractions generally show differences smaller than the errors of the method, irrespective of (001) illite crystallinity values, probably due to metamorphic recrystallization. Intermediate pressure metamorphism of the Ordovician–Silurian Clew Bay Group indicates slow subduction, allowing partial thermal re-equilibration before exhumation. In contrast, the Croagh Patrick Group Laurentian shelf-sediments underwent high-pressure alteration, suggesting rapid subduction/exhumation, synchronous with strike-slip faulting. The Murrisk Group, which underwent high-intermediate pressure metamorphism in an Ordovician back-arc, forms a separate terrane to the Croagh Patrick Group to the north and also to the Ordovician Lough Nafooey and Tourmakeady groups and Rosroe Formation in the south, in which low-intermediate pressure alteration occurred. These, together with the Silurian North Galway Group, may have undergone heating due to movement over or deposition on the hot Gowlaun Detachment as the Connemara Dalradian was exhumed. The South Connemara Group also underwent a high-pressure alteration, consistent with its inferred subduction environment. Evidence of contact alteration, due to known or inferred buried late- to post-Caledonian granitoid plutons, has been found in the Clew Bay, Louisburg–Clare Island, Croagh Patrick, Murrisk and South Connemara groups. These show evidence of lower-pressure alteration than the surrounding country-rocks.
The finite-length square cylinder near wake
Authors: WANG H. F. , ZHOU Y.
Published: October 2009

This paper reports an experimental investigation of the near wake of a finite-length square cylinder, with one end mounted on a flat plate and the other free. The cylinder aspect ratio or height-to-width ratioH/dranges from 3 to 7. Measurements were carried out mainly in a closed-loop low-speed wind tunnel at a Reynolds numberRed, based ondand the free-stream velocity of 9300 using hot-wire anemometry, laser Doppler anemometry and particle image velocimetry (PIV). The planar PIV measurements were performed in the three orthogonal planes of the three-dimensional cylinder wake, along with flow visualization conducted simultaneously in two orthogonal planes (Red= 221). Three types of vortices, i.e. the tip, base and spanwise vortices were observed and the near wake is characterized by the interactions of these vortices. Both flow visualization and two-point correlation point to an inherent connection between the three types of vortices. A model is proposed for the three-dimensional flow structure based on the present measurements, which is distinct from previously proposed models. The instantaneous flow structure around the cylinder is arch-type, regardless ofH/d, consisting of two spanwise vortical ‘legs’, one on each side of the cylinder, and their connection or ‘bridge’ near the free end. Both tip and base vortices are the streamwise projections of the arch-type structure in the (y,z) plane, associated with the free-end downwash flow and upwash flow from the wall, respectively. Other issues such as the topological characteristics, spatial arrangement and interactions among the vortical structures are also addressed.
A mechanistic model for the spectral induced polarization of clay materials
Authors: Leroy P. , Revil A.
Published: October 2009

Water‐saturated clay‐rich media exhibit low‐frequency (1 Hz to 1 MHz) effective conductivity and effective permittivity dispersions that are the consequence of both the polarization of the mineral/water interface coating the surface of the grains and the Maxwell‐Wagner polarization. These low‐frequency properties are modeled by combining (1) a complexation model of the surface properties of clay minerals (kaolinite, illite, and smectite), (2) a polarization model of the Stern layer (the inner portion of the electrical double layer coating the surface of the minerals), and (3) a macroscopic model comprising the electrochemical polarization of the grains and the contribution of the Maxwell‐Wagner effect. The macroscopic model is based on the differential effective medium theory. It includes a convolution product with the grain size distribution. For kaolinite, the diffuse layer occupies a small fraction of the pore space and is considered as part of the surface of the grains. This is due to the low specific surface area of kaolinite. In the case of illite and smectite, the situation is different. Because of the high specific surface areas of these minerals, the diffuse layer occupies a large fraction of the pore space and is considered as part of the pore space and is described using a Donnan equilibrium model. We obtain excellent comparisons between various experimental data reported in the literature and our model. Then, we considered low‐porosity (compacted or cemented) clay rocks and shales. Here too, we obtained a good agreement between the data and the predictions of a model based on a volume‐averaging approach. We also note that at very low frequencies (<1 Hz), another polarization mechanism exists that is not reproduced by our model. We believe that this polarization corresponds to a nonlinear membrane polarization contribution.
Remote global‐scale observations of intense low‐altitude ENA emissions during the Halloween geomagnetic storm of 2003
Authors: Pollock C. J. , Isaksson A. , Jahn J.‐M. , Søraas F. , Sørbø M.
Published: October 2009

Remote observations of energetic neutral atoms (ENAs) emitted from low altitude at a few keV in Earth's northern and southern hemispheres during the main phase of the 29 October 2003 geomagnetic storm are presented and compared with near simultaneous in situ measurements of precipitating ions with similar energies. A simple analysis of the ENA images yields estimates of the invariant latitudes and local pitch angles of the ENAs at their emission points. The invariant latitude distribution of the ENA emission points is similar to that of the precipitating ions and peaks near 60°. The pitch‐angle distributions of the ENAs at their emission points are peaked near 90° but favor the upward (escaping) direction. We interpret the ENAs as re‐emissions of the precipitating ions observed in situ, after interaction with Earth's upper atmosphere.
Basin mode of Indian Ocean sea surface temperature and Northern Hemisphere circumglobal teleconnection
Authors: Yang Jianling , Liu Qinyu , Liu Zhengyu , Wu Lixin , Huang Fei
Published: October 2009

Observational analysis and model experiments show that the sea surface temperature anomaly associated with the Indian Ocean Basin mode (IOBM), which persists from spring to summer, can generate significant circumglobal teleconnection (CGT) in the Northern Hemisphere summer midlatitude atmosphere. A warm IOBM can induce a new atmospheric heating source in the south Asia through a positive feedback. An enhanced Indian summer monsoon through the increased precipitation in the south Asia induces an atmospheric heating source there. This new atmospheric heating source generates an anomalous high to its northwest over the western‐central Asia, which in turn generates an eastward downstream atmospheric wave train, forming the CGT.