bluuebunny/crossref_metadata_2025 huggingface dataset:
Binding and acid-base properties of novel photosensitizing drugs in micellar and liposome solutions
Authors: Kropacheva Tatyana N. , van der Haas Richard N. S. , van der Steen Robert , Gast Peter , Schuitmaker Hans J. , Lugtenburg Johan
Published: July 2009

The binding and acid-base equilibria of the two novel mesoporphyrin derivatives, PB07 and PB109 (quino[4,4a,5,6-efg]- annulated 7-demethyl-8-deethylmesoporphyrin and 2'-cyano-8'-formyl-N'-methyl-1',1a',5a',6'-tetrahydroacrido [4,5,5a,6-bcd]- annulated 2,3-dihydromesoporphyrin, resp.), which are promising agents for photodynamic therapy (PDT), were studied in aqueous solutions of different surfactants (Triton X-100 (TX-100), dodecyl maltoside (DDM), cetyltrimethylammonium bromide (CTAB), lithium dodecyl sulfate (LDS)) and phosphatidyl choline (PC) liposomes. In all cases, the porphyrins are solubilized at neutral/alkaline pH in monomeric form and remain micelle/liposome-bound independently of their ionization state. The dissociation constants of the solubilized porphyrins are found to be influenced by the charge of the surface groups of the carrier. The protonation of pyrrole/quinoline nitrogens of the studied porphyrins is facilitated in the following order: LDS ≫TX-100 (DDM, PC liposomes) > CTAB. The dissociation constants of PB 07 carboxylic groups are similar in neutral/cationic micellar and liposome solutions and are significantly decreased for LDS-bound pigment. The results provide necessary information for the optimization of delivery systems for PB 07 and PB 109 when applied as sensitizers in PDT.
Hydrogen bonding interaction on the heme-bound ligand in the heme-based O2 sensor protein
Authors: Nishimura Muneto , Yoshimura Hideaki , Ozawa Kazumichi , Yoshioka Shiro , Kubo Minoru , Kitagawa Teizo , Aono Shigetoshi
Published: July 2009

HemAT is a signal transducer protein responsible for aerotaxis control of some bacteria and archaea, which contains a heme-containing globin domain as the sensor of its physiological effector, O 2. The interaction between the heme-bound ligand and the surrounding amino acid residue(s) plays a crucial role for selective sensing of O 2 and signal transduction by HemAT. In this work, we have elucidated by resonance Raman spectroscopy how O 2 and CO interact with HemAT- Hs and HemAT- Rr , HemAT from Halobacterium salinarum and Rhodospirillum rubrum, respectively. HemAT- Hs and HemAT- Rr showed three conformers in the O 2-bound form, as is the case of HemAT- Bs , HemAT from Bacillus subtilis. Though the hydrogen bonding patterns observed in the three conformers were the same for HemAT- Bs , HemAT- Hs , and HemAT- Rr , the involved residues for the hydrogen bonding interaction were different from one another.
Conformational study on sterically hindered bis(arylimino)-isoindolines
Authors: Bröring Martin , Kleeberg Christian
Published: July 2009

Single crystal X-ray crystallographic analyses of three bis(arylimino)isoindoline ligands (bai's) with terminal thiazolyl (bti) and pyridyl groups (bpi) and differing degrees of sterical encumbrance are reported and discussed in the context of conformation, conjugation, and coordination properties. 4-Mebti 2 forms yellow plates from CH 2 Cl 2/pentane at -20 °C in P21/c with Z = 4, 6-Mebpi 3 crystallizes as yellow blocks from CH 2 Cl 2/n-hexane at -20 °C in P21/c with Z = 8 (two independant molecules), and 4-tBubti 4 is obtained from CHCl 3/n-hexane at ambient temperature as yellow plates in P21 with Z = 2. The latter compound forms pseudomerohedrically twinned crystals and was treated accordingly in the structure solution and refinement. The resulting molecular structures provide insight into the stepwise increase of sterical hindrance from 2 over 3 to 4 which results in a rotational displacement of one of the terminal heterocycles from the major plane. The ease of this rotation process proves a low degree of conjugation in bis(arylimino)isoindolines and stands in contrast with the formation of a helically distorted structure for a related, though strongly conjugated, t-butyl terminated tripyrrin 1.
Synthesis and structural characterization of a new self-assembled disulfide linked meso-tetrakis-porphyrin macromolecular array
Authors: Sobral Abilio J. F. N. , Justino Licinia L. G. , Santos Ana C. C. , Silva Joana A. , Arranja Cláudia T. , Silva Manuela Ramos , Beja Ana Matos
Published: July 2009

The synthesis of a new self-assembled porphyrin macrostructure based on disulfide bonds, is presented. This constitutes a new way to directly connect porphyrins in macromolecular arrays, to complement the usual methods of intermolecular hydrogen bonds and metal coordination bonding.
Adventures in photodynamic therapy: 1976-2008
Authors: Kessel David
Published: July 2009

While the concept of photodynamic therapy dates from 1900, and there have been periodic re-discoveries, the clinical era really began with the studies by Dougherty and associates in the early 1970s. This report relates my encounter with the field of PDT, along with experimental approaches to the elucidation of pertinent phototoxic mechanisms.
Reductive demetalation of copper corroles: first simple route to free-base β-octabromocorroles
Authors: Capar Can , Thomas Kolle Ekaney , Ghosh Abhik
Published: July 2009

Although the chemistry of corroles has grown spectacularly in recent years, the field has been marred by the lack of convenient protocols for demetalation of metallocorroles. Reported herein is a superior procedure for demetalating copper corroles with concentrated H 2SO4 and 5-200 equiv FeCl 2 or SnCl 2. The yields obtained with this reductive procedure are generally substantially better than with CHCl 3/ H 2SO4, CH 2Cl2/ H 2SO4, or H 2SO4 alone. With an oxidation-prone metallocorrole such as Cu [ T (p- OMeP ) C ], the reductive protocol was essential for obtaining any measurable yield of the free base at all. Free-base β-octabromo-meso-triarylcorroles were also obtained in pure form, in good yields, and with relative ease via this procedure.
Explorations in metalloporphyrin stereochemistry, physical properties and beyond
Authors: Scheidt W. Robert
Published: July 2009

A review of selected portions of our work in the area of porphyrin structure and physical characterization is presented. Topics covered include early work on periodic trends in first row transition metalloporphyrins, a survey of electronic structure of iron derivatives including spin-state trends, ligand orientation effects and the elucidation of unusual low-spin states for iron(II). A discussion of the different types of high-spin iron(II) complexes and the effects of hydrogen bonding is given. A survey of nitric oxide (NO) derivatives is presented as well as a brief introduction into the use of nuclear resonance vibrational spectroscopy for the study of iron porphyrins and heme proteins.
Synthesis of fullerene-porphyrin conjugates from a C60-benzaldehyde building block
Authors: Nierengarten Jean-François
Published: July 2009

A fullerene derivative bearing an aldehyde group has been prepared and used as starting material for the synthesis of various porphyrins. The C 60-porphyrin conjugates thus obtained have revealed unique conformational properties resulting from the symmetry of the 1,3-phenylenebis(methylene)-tethered fullerene cis-2 bis-adduct subunit.
Synthesis of unsymmetrical porphyrin triad containing three different porphyrin subunits assembled by covalent and non-covalent interactions
Authors: Punidha Sokkalingam , Rai Smita , Ravikanth Mangalampalli
Published: July 2009

Cis-21,23-dithiaporphyrin building block containing one iodophenyl and one pyridyl functional group at meso positions was synthesized by condensing unsymmetrical thiophene diol and symmetrical 16-thiatripyrrin under refluxing propionic acid conditions. The 21,23-dithiaporphyrin building block was coupled with mono-functionalized 21-thiaporphyrin building block containing meso-phenylethyne functional group under mild Pd (0) coupling conditions. The steady-state and time-resolved fluorescence studies support an efficient energy transfer in the singlet excited state from N 3 S porphyrin subunit to N 2 S 2 porphyrin subunit in the dyad. The N 3 S - N 2 S 2 porphyrin dyad was then treated with RuTPP ( CO )( EtOH ) in toluene at refluxing temperature and purified by column chromatography to afford a porphyrin triad containing N 3 S , N 2 S 2 and RuN 4 porphyrin subunits assembled using both covalent and non-covalent interactions. The photophysical properties showed the fluorescence quenching of N 3 S and N 2 S 2 porphyrin subunits in triad due to heavy ruthenium ion which was coordinated to meso-pyridyl ' N ' of N 2 S 2 porphyrin subunit of porphyrin triad.
A new route to carbon monoxide adducts of heme proteins
Authors: Makarov Sergei V. , Salnikov Denis S. , Pogorelova Anna S. , Kis Zoltan , Silaghi-Dumitrescu Radu
Published: July 2009

Sulfoxylate SO 2 H −( SO 22−), a strong reducing agent readily produced by hydrolysis of thiourea dioxide, reacts with ferric myoglobin ( Mb ) to reversibly produce Fe (II)- Mb , starting from either aerobic or anaerobic conditions. Exposure of Fe (II)- Mb to excess sulfoxylate further produces Fe (II)- CO - Mb . Fe (II)- Mb can be regenerated by reoxidation with ferricyanide at this stage; hemin, rubredoxin and cytochrome c show a similar reactivity towards sulfoxylate. The source of CO is not the protein moiety, nor is it the heme or the thiourea dioxide – but rather CO 2, via its reaction with sulfoxylate when the latter is used in large excess. These findings provide a convenient single-step route to carbon monoxide heme adducts, without the need to manipulate toxic CO gas.
Synthesis andin vitroanticancer activity of water-soluble cationic pyridylporphyrins and their metallocomplexes
Authors: Tovmasyan Artak G. , Babayan Nelli S. , Sahakyan Lida A. , Shahkhatuni Aleksan G. , Gasparyan Genadi H. , Aroutiounian Rouben M. , Ghazaryan Robert K.
Published: July 2009

Tetrapyrrolic compounds such as porphyrins are known to be prospective chemotherapeutics and photosensitizers for cancer treatment and diagnosis. In this work, water-soluble, meso-substituted cationic pyridyl-porphyrins and their metallocomplexes bearing various central metal atoms ( Ag , Zn , Co , and Fe ) in the porphine ring and various functional groups (allyl, oxyethyl, butyl, and methallyl) at the nitrogen atom in the pyridine ring were synthesized and characterized by1H and13C NMR and UV-visible spectroscopy. Cytotoxic and photodynamic activities of new porphyrins and their metal derivatives were investigated in vitro (KCL-22 cancer cell line of human chronic myeloid leukemia). The cytotoxicity of porphyrins was shown to be dependent on the presence and type of the central metal atom in the porphine ring. Ag -derivatives were more cytotoxic than Co −, Zn −, and Fe − metallocomplexes. The porphyrins bearing allyl-functional groups were evidenced to be more cytotoxic than those which included butyl-, oxyethyl-, and methallyl-groups. The change of nitrogen position in the pyridine ring of Ag -metalloporphyrins from 3(3-N-pyridylporphyrins) to 4(4-N-pyridylporphyrins) induced an increase in the cytotoxic activity of metallocomplexes. All synthesized Ag-metalloporphyrins, except, the oxyethyl-containing one were more cytotoxic than cisplatin. Allyl containing free porphyrin and its Zn -metallocomplex had higher phototoxicity than Ag −, Co −, and Fe -metalloporphyrins. The results obtained can be useful for further investigation of new porphyrins as potential chemotherapeutics and photosensitizers.
Electrochemistry and spectroelectrochemistry of tetra-α-substituted metallophthalocyanines
Authors: Ou Zhongping , Jiang Zhou , Chen Naisheng , Huang Jinling , Shen Jing , Kadish Karl M.
Published: July 2009

Four tetra-α-substituted phthalocyanines, represented as [( OR )4 Pc ] M where OR is 2,2,4-tri-methyl-3-pentoxy and M = Co (II), Ni (II), Cu (II) or Zn (II), were investigated as to their electrochemistry, UV-visible and ESR spectroscopy. The electron-donating groups on the four α-positions of the phthalocyanine macrocycles lead to a 40 nm red-shift in the position of the most intense band in the UV-visible spectrum as compared to the unsubstituted ( Pc ) M derivative with the same central metal ion under the same solution conditions. The cobalt, nickel and copper complexes of [( OR )4 Pc ] M are soluble in nonaqueous media and show no evidence for aggregation at the millimolar concentration levels needed for electrochemical measurements. The Zn (II) complex aggregates in DMF at these concentrations but monomers are formed upon diluting the solution or by adding a complexing axial ligand such as pyridine. The first reduction and first oxidation of [( OR )4 Pc ] Co (II) leads to formation of a Co (I) and Co (III) phthalocyanine and this contrasts with the first reduction and first oxidation of the Ni (II), Cu (II) and Zn (II) derivatives where electron addition and electron abstraction occur at the conjugated macrocycle, leading to π-anion and π-cation radicals, respectively.
Spectral-luminescent, photochemical, and nonlinear optical properties of some cyclotetrapyrrole derivatives in liquid and solid media
Authors: Kuznetsova Rimma T. , Ermolina Elena G. , Gadirov Ruslan M. , Mayer Georgy V. , Stuzhin Pavel A. , Kalashnikova Irina P. , Korovin Yuri V.
Published: July 2009

Spectral-luminescent, nonlinear, and photochemical characteristics of some cyclotetrapyrrole compounds are investigated. Methods of investigation are described, and results obtained that can be used for the development of laser limiters and phosphors are presented. It is demonstrated that the protonation efficiency changes under excitation and when going from liquid solutions to solid media. A new assumption on the influence of solution acidification on the limitation of high-power emission and photostability is discussed.
Polypeptides with pendant porphyrins of defined sequence of chromophores: towards artificial photosynthetic systems
Authors: Aziat Farid , Rein Régis , Peón Jorge , Rivera Ernesto , Solladié Nathalie
Published: July 2009

In this paper we now report our ongoing progress in the preparation of artificial photosynthetic systems through the preparation of light harvesting multi-porphyrins. A tetramer, constituted of a central dipeptide functionalized by two free-base porphyrins and surrounded by one amino-acid bearing a pendant Zn ( II ) porphyrin on each side, has been chosen. The optical and photophysical properties of this tetramer have been studied by absorption and fluorescence spectroscopy. In addition, the energy transfer phenomenon has been studied and monitored by femtosecond time-resolved fluorescence. Our results indicate that the excited state dynamics redounding in the excitation being localized in the inner free-base porphyrins takes place in the time scale of approximately 1 ps.
Design of metalloporphyrin-based dendritic nanoprobes for two-photon microscopy of oxygen
Authors: Lebedev Artem Y. , Troxler Thomas , Vinogradov Sergei A.
Published: July 2009

Metalloporphyrin-based phosphorescent nanoprobes are being developed for two-photon microscopy of oxygen. In these molecular constructs, the generation of porphyrin triplet states following two-photon excitation is induced by the intramolecular Förster-type resonance energy transfer from a covalently attached 2P antenna. In the earlier developed prototypes, electron transfer between the antenna and the metalloporphyrin strongly interferred with the phosphorescence, reducing the sensitivity and the dynamic range of the sensors. By tuning the distances between the antenna and the core, and adjusting their redox potentials, the unwanted electron transfer could be prevented. An array of phosphorescent Pt porphyrins (energy transfer acceptors) and 2P dyes (energy transfer donors) was screened using dynamic quenching of phosphorescence, and the FRET-pair with the minimal ET rate was identified. This pair, consisting of Coumarin-343 and Pt meso-tetra-(4-alkoxyphenyl)porphyrin, was used to construct a probe in which the antenna fragments were linked to the termini of G3 poly(arylglycine) (AG) dendrimer with PtP core. The folded dendrimer formed an insulating layer between the porphyrin and the antenna, simultaneously controlling the rate of oxygen quenching (Stern-Volmer oxygen quenching constant). Modification of the dendrimer periphery with oligoethyleneglycol residues made the probe's signal insensitive to the presence of proteins and other macromolecular solutes.
Nanostructured cobalt phthalocyanine single-walled carbon nanotube platform: electron transport and electrocatalytic activity on epinephrine
Authors: Agboola Bolade O. , Mocheko Alfred , Pillay Jeseelan , Ozoemena Kenneth I.
Published: July 2009

The fabrication, characterization and application of edge-plane pyrolytic graphite electrode modified with acid-functionalized single-walled carbon nanotubes, nanostructured cobalt phthalocyanine and a mixture of both, towards epinephrine detection and analysis are described. The morphological features of the films were evaluated using atomic force microscopy (AFM). Electrochemistry of these electrodes in [ Fe ( CN )6]3−/4− using cyclic voltammetry and electrochemical impedance spectroscopy showed higher peak current responses with accompanying low electron-transfer resistances in comparison to the bare electrode. The edge-plane pyrolytic graphite-single-walled carbon nanotubes-nanostructured cobalt phthalocyanine electrode exhibited good electrocatalytic activity towards epinephrine oxidation with enhanced peak currents. Analytical studies using edge-plane pyrolytic graphite-single-walled carbon nanotubes-nanostructured cobalt phthalocyanine electrode proved that the electrode is suitable for sensitivity determination of epinephrine in pH 5 conditions judging from the good sensitivity (8.71 ± 0.31 A.M−1), and limit of detection (0.04 µM) and quantification (1.31 µM) obtained. Determination of EP in the absence and presence of ascorbic acid in phosphate buffer pH 5 conditions was carried out and it was established that the presence of AA did not interfere in EP analysis. Rotating disk electrode experiments proved that the catalytic rate constant was 2.28 × 1016 mM−1.s−1.
NUMERICAL SIMULATION OF Si NANOPARTICLE FORMATION BY SILANE PYROLYSIS
Authors: WOO DAEKWANG , SEO JAEJUNG , KIM TAESUNG
Published: July 2009

This paper presents a numerical model of silicon nanoparticle formation process during silane ( SiH 4) pyrolysis. Aerosol dynamics model, which includes particle growth by surface reaction, coagulation, and transport, was coupled with a chemical kinetics model using CHEMKIN 4.1.1 with particle tracking module (PTM). The general dynamic equation (GDE) was solved by using the method of moment (MOM). The effect of reactor temperature, pressure, total flow rate, and initial silane concentration was successfully investigated under conditions typically used for atmospheric-pressure silane pyrolysis system and we compared the calculated results on particle formation with published experimental data. The simulation results show that particle formation is very sensitive to temperature and initial silane concentration. We observed that numerical simulation results showed a good agreement with experimental data for parameters such as particle concentration, diameter, growth rate, and total volume concentration.
Algorithm 895
Authors: Backeljauw Franky , Cuyt Annie
Published: July 2009

The continued fractions for special functions package (in the sequel abbreviated as CFSF package) complements a systematic study of continued fraction representations for special functions. It provides all the functionality to create continued fractions, in particular
k
-periodic or limit
k
-periodic fractions, to compute approximants, make use of continued fraction tails, perform equivalence transformations and contractions, and much more. The package, developed in Maple, includes a library of more than 200 representations of special functions, of which only 10% can be found in the 1964 NBS
Handbook of Mathematical Functions with Formulas, Graphs and Mathematical Tables
by M. Abramowitz and I. Stegun.
Learning through games
Authors: Hoffmann Leah
Published: July 2009

Electronic games can inspire players to explore new ideas and concepts. By gaining a better understanding of the dynamic between player and game, researchers hope to develop more interesting and effective approaches.
EducationAlice 3
Authors: Dann Wanda , Cooper Stephen
Published: July 2009

The innovative Alice 3 programming environment, currently in beta testing, teaches students to program with Alice and Java software.
Privacy and securityAn ethics code for U.S. intelligence officers
Authors: Snow Brian , Brooks Clinton
Published: July 2009

Debating and arguing the points of a proposed code of behavior to provide guidance in making choices can produce the most effective ethics training.
ViewpointTime for computer science to grow up
Authors: Fortnow Lance
Published: July 2009

As the computer science field has evolved, so should the methods for disseminating computing research results.
The pathologies of big data
Authors: Jacobs Adam
Published: July 2009

Scale up your datasets enough and your apps come undone. What are the typical problems and where do the bottlenecks surface?
CTO Roundtable
Authors: Creeger Mache
Published: July 2009

The age of cloud computing has begun. How can companies take advantage of the new opportunities it provides?
Boolean satisfiability from theoretical hardness to practical success
Authors: Malik Sharad , Zhang Lintao
Published: July 2009

Satisfiability solvers can now be effectively deployed in practical applications.
Global software development
Authors: Conchúir Eoin Ó , Ågerfalk Pär J. , Olsson Helena H. , Fitzgerald Brian
Published: July 2009

Introduction

Global Software Development (GSD) is increasingly becoming the normal practice in the software industry, readily evidenced by U.S. estimates that the value of the offshore software development market has increased 25-fold over the past 10 years, to the extent that one-quarter of U.S. spending on application development, integration and management services is expected to go off-shore according to recent predictions. There are many potential benefits that can arise from GSD. The most frequently cited one is that of reduced development costs due to the salary savings possible. Also, GSD can lead to reduced development duration due to greater time zone effectiveness as companies practice the so-called 'follow-the-sun' software development model. GSD also affords new opportunities for cross-site modularization of development work, potential access to a larger and better-skilled developer pool, and the possibility of greater innovation, learning and transfer of best practices. Finally, GSD can facilitate closer proximity to markets and customers.

However, GSD also introduces a number of challenges in relation to communication, coordination and control of the development process. These arise due to the distances involved in three dimensions -- geographical, temporal, and socio-cultural (See Figure 1). As a consequence, much research and practice has focused on trying to find ways to overcome the GSD challenges identified in Figure 1. In the literature to date, the potential benefits of GSD are usually just mentioned very briefly, if they are mentioned at all, and the realization of these benefits seems to be more or less taken for granted. The primary focus instead is on how the problems inherent in GSD might be addressed. Here, we reverse this trend and focus instead on the benefits and the extent to which they are actually being realized in practice in three global companies practicing GSD.
3D modeling of complex and detailed cultural heritage using multi-resolution data
Authors: Remondino Fabio , Girardi Stefano , Rizzi Alessandro , Gonzo Lorenzo
Published: July 2009

The article reports the interdisciplinary project of the virtualization of the Great Inscription of Gortyna, Crete, for 3D documentation, structural studies, and physical replica purposes. The digitization of the longest epigraphic text of the Greek civilization (6 m long and 1.75 m high, with approximately 2--3 mm-depth engraved letters) and its surrounding heritage area (around 30 × 30 m), required long planning and the construction of a dedicated acquisition system to speed up the surveying time, limited to few hours per day. Primarily, range sensors were employed in a multi-resolution way, digitizing detailed parts in high resolution and less smoothed areas with lower geometric resolution. Some selected areas were also modeled with our multiphoto geometrically constrained image matching approach to demonstrate that the same accuracy and details can be achieved using either scanners or photogrammetry. The derived 3D model of the heritage is now the basis for further archaeological studies on the incision techniques and a deeper structural analysis on the monument. The challenges of the work stay in the acquisition, processing, and integration of the multi-resolution data as well as their interactive visualization.
The Molecular Basis of Organ Formation: Insights From theC. elegansForegut
Authors: Mango Susan E.
Published: July 2009

The digestive tracts of many animals are epithelial tubes with specialized compartments to break down food, remove wastes, combat infection, and signal nutrient availability. C. elegans possesses a linear, epithelial gut tube with foregut, midgut, and hindgut sections. The simple anatomy belies the developmental complexity that is involved in forming the gut from a pool of heterogeneous precursor cells. Here, I focus on the processes that specify cell fates and control morphogenesis within the embryonic foregut (pharynx) and the developmental roles of the pharynx after birth. Maternally donated factors in the pregastrula embryo converge on pha-4, a FoxA transcription factor that specifies organ identity for pharyngeal precursors. Positive feedback loops between PHA-4 and other transcription factors ensure commitment to pharyngeal fate. Binding-site affinity of PHA-4 for its target promoters contributes to the progression of the pharyngeal precursors towards differentiation. During morphogenesis, the pharyngeal precursors form an epithelial tube in a process that is independent of cadherins, catenins, and integrins but requires the kinesin zen-4/MKLP1. After birth, the pharynx and/or pha-4 are involved in repelling pathogens and controlling aging.
Growing Up with HIV: Children, Adolescents, and Young Adults with Perinatally Acquired HIV Infection
Authors: Hazra Rohan , Siberry George K. , Mofenson Lynne M.
Published: July 2009

Tremendous success in the prevention and treatment of pediatric HIV in high-resource countries has changed the face of the epidemic. A perinatally HIV-infected child now faces a chronic disease rather than a progressive, fatal one. However, these successes pose new challenges as perinatally HIV-infected youth survive into adulthood. These include maintaining adherence to long-term, likely life-long therapy; selecting successive antiretroviral drug regimens, given the limited availability of pediatric formulations and the lack of pharmacokinetic and safety data in children; and overcoming extensive drug resistance in multi-drug-experienced children. Pediatric HIV care now focuses on morbidity related to long-term HIV infection and its treatment. Survival into adulthood of perinatally HIV-infected youth in high-resource countries encourages expansion of pediatric treatment programs in low-resource countries, where most HIV-infected children live, and provides important lessons about how the epidemic changes with increasing access to antiretroviral therapy for children.
An Adaptive Message Passing MPSoC Framework
Authors: Marchesan Almeida Gabriel , Sassatelli Gilles , Benoit Pascal , Saint-Jean Nicolas , Varyani Sameer , Torres Lionel , Robert Michel
Published: July 2009

Multiprocessor Systems‐on‐Chips (MPSoCs) offer
superior performance while maintaining flexibility and reusability
thanks to software oriented personalization. While most
MPSoCs are today heterogeneous for better meeting the targeted
application requirements, homogeneous MPSoCs may become
in a near future a viable alternative bringing other benefits
such as run‐time load balancing and task migration. The work
presented in this paper relies on a homogeneous NoC‐based
MPSoC framework we developed for exploring scalable and
adaptive on‐line continuous mapping techniques. Each processor
of this system is compact and runs a tiny preemptive operating
system that monitors various metrics and is entitled to take
remapping decisions through code migration techniques. This
approach that endows the architecture with decisional capabilities
permits refining application implementation at run‐time according
to various criteria. Experiments based on simple policies are
presented on various applications that demonstrate the benefits
of such an approach.
Defaultable Game Options in a Hazard Process Model
Authors: Bielecki Tomasz R. , Crépey Stéphane , Jeanblanc Monique , Rutkowski Marek
Published: July 2009

The valuation and hedging of defaultable game options is studied in a hazard process model of credit risk. A convenient pricing formula with respect to a reference filteration is derived. A connection of arbitrage prices with a suitable notion of hedging is obtained. The main result shows that the arbitrage prices are the minimal superhedging prices with sigma martingale cost under a risk neutral measure.
An Exact Method for the 2D Guillotine Strip Packing Problem
Authors: Bekrar Abdelghani , Kacem Imed
Published: July 2009

We consider the two-dimensional strip packing problem with guillotine cuts. The problem consists in packing a set of rectangular items on one strip of widthWand infinite height. The items packed without overlapping must be extracted by a series of cuts that go from one edge to the opposite edge (guillotine constraint). To solve this problem, we use a dichotomic algorithm that uses a lower bound, an upper bound, and a feasibility test algorithm. The lower bound is based on solving a linear program by introducing new valid inequalities. A new heuristic is used to compute the upper bound. Computational results show that the dichotomic algorithm, using the new bounds, gives good results compared to existing methods.
On Mass Loading and Dissipation Measured with Acoustic Wave Sensors: A Review
Authors: Voinova Marina V.
Published: July 2009

We summarize current trends in the analysis of physical properties (surface mass density, viscosity, elasticity, friction, and charge) of various thin films measured with a solid‐state sensor oscillating in a gaseous or liquid environment. We cover three different types of mechanically oscillating sensors: the quartz crystal microbalance with dissipation (QCM‐D) monitoring, surface acoustic wave (SAW), resonators and magnetoelastic sensors (MESs). The fourth class of novel acoustic wave (AW) mass sensors, namely thin‐film bulk acoustic resonators (TFBARs) on vibrating membranes is discussed in brief. The paper contains a survey of theoretical results and practical applications of the sensors and includes a comprehensive bibliography.
Sb‐SnO2‐Nanosized‐Based Resistive Sensors for NO2 Detection
Authors: Krishnakumar T. , Jayaprakash R. , Pinna N. , Donato A. , Donato N. , Micali G. , Neri G.
Published: July 2009

A study over Sb‐promoted tin oxide nanopowders for sensing applications is reported. SnO2 nanopowders pure and promoted with 5 wt% of antimony were prepared by wet chemical methods and widely characterized by TEM, XRD, and XPS techniques.
Thick film resistive sensors were fabricated by depositing the synthesized nanopowders by drop‐coating on interdigited alumina substrates. The sensing characteristics of the pure SnO2 and Sb‐promoted sensors for the monitoring of trace level of NO2 were studied. The response of the sensors to water vapor was also investigated, revealing that Sb acts favorably eliminating the interference of humidity.
Systematic Examination of the Updated Framingham Heart Study General Cardiovascular Risk Profile
Authors: Marma Amanda K. , Lloyd-Jones Donald M.
Published: July 2009

Background—

An updated Framingham risk prediction tool was recently published. It features an expanded end point of general cardiovascular disease and a “vascular age” risk communication analogy.

Methods and Results—

We systematically examined the tool to determine which risk factor combinations allow risk thresholds to be reached and how different risk factor burdens translate into vascular age. We varied risk factor levels in isolation and combination and observed risk output patterns, with high risk defined as ≥20% 10-year predicted risk. As expected, we found that age is the major determinant of 10-year predicted risk for both men and women. Younger individuals tend not to exceed 20% 10-year risk even with multiple risk factors, although with marked risk factor burden, including both smoking and diabetes mellitus, men as young as 35 years of age and women as young as 40 years of age can be classified as high risk. For the risk factor levels we entered, predicted risk ranges from 3.1% to 46.8% for a 45-year-old man and 2.4% to 42.7% for a 55-year-old woman. Likewise, vascular age ranges from 37 to >80 years for a 45-year-old man and 39 to >80 years for a 55-year-old woman.

Conclusions—

The inclusion of noncoronary end points in this tool expands the range of predicted risks for men and women at all ages studied. Nevertheless, many younger individuals with high risk factor burden have low 10-year predicted risk. Wide ranges of “vascular age” are available for most chronological ages to assist with risk communication.
Correlation of Intravascular Ultrasound Findings With Histopathological Analysis of Thrombus Aspirates in Patients With Very Late Drug-Eluting Stent Thrombosis
Authors: Cook Stéphane , Ladich Elena , Nakazawa Gaku , Eshtehardi Parham , Neidhart Michel , Vogel Rolf , Togni Mario , Wenaweser Peter , Billinger Michael , Seiler Christian , Gay Steffen , Meier Bernhard , Pichler Werner J. , Jüni Peter , Virmani Renu , Windecker Stephan
Published: July 2009

Background—

Intravascular ultrasound of drug-eluting stent (DES) thrombosis (ST) reveals a high incidence of incomplete stent apposition (ISA) and vessel remodeling. Autopsy specimens of DES ST show delayed healing and hypersensitivity reactions. The present study sought to correlate histopathology of thrombus aspirates with intravascular ultrasound findings in patients with very late DES ST.

Methods and Results—

The study population consisted of 54 patients (28 patients with very late DES ST and 26 controls). Of 28 patients with very late DES ST, 10 patients (1020±283 days after implantation) with 11 ST segments (5 sirolimus-eluting stents, 5 paclitaxel-eluting stents, 1 zotarolimus-eluting stent) underwent both thrombus aspiration and intravascular ultrasound investigation. ISA was present in 73% of cases with an ISA cross-sectional area of 6.2±2.4 mm
2
and evidence of vessel remodeling (index, 1.6±0.3). Histopathological analysis showed pieces of fresh thrombus with inflammatory cell infiltrates (DES, 263±149 white blood cells per high-power field) and eosinophils (DES, 20±24 eosinophils per high-power field; sirolimus-eluting stents, 34±28; paclitaxel-eluting stents, 6±6;
P
for sirolimus-eluting stents versus paclitaxel-eluting stents=0.09). The mean number of eosinophils per high-power field was higher in specimens from very late DES ST (20±24) than in those from spontaneous acute myocardial infarction (7±10), early bare-metal stent ST (1±1), early DES ST (1±2), and late bare-metal stent ST (2±3;
P
from ANOVA=0.038). Eosinophil count correlated with ISA cross-sectional area, with an average increase of 5.4 eosinophils per high-power field per 1-mm
2
increase in ISA cross-sectional area.

Conclusions—

Very late DES thrombosis is associated with histopathological signs of inflammation and intravascular ultrasound evidence of vessel remodeling. Compared with other causes of myocardial infarction, eosinophilic infiltrates are more common in thrombi harvested from very late DES thrombosis, particularly in sirolimus-eluting stents, and correlate with the extent of stent malapposition.
Immunoglobulin M Is Required for Protection Against Atherosclerosis in Low-Density Lipoprotein Receptor–Deficient Mice
Authors: Lewis Myles J. , Malik Talat H. , Ehrenstein Michael R. , Boyle Joseph J. , Botto Marina , Haskard Dorian O.
Published: July 2009

Background—

Immunoglobulin M (IgM) natural antibodies bind oxidatively-modified low-density lipoprotein (LDL) and apoptotic cells and have been implicated as being important for protection against atherosclerosis. We have directly investigated the requirement for IgM by studying the effects of IgM deficiency in LDL receptor–deficient (

Ldlr
−/−

) mice.

Methods and Results—

Mice deficient in serum IgM (sIgM) or complement C1q were crossed with

Ldlr
−/−

mice and studied on both low-fat and high-fat semisynthetic diets. On both diets, en face and aortic root atherosclerotic lesions in

sIgM.Ldlr
−/−

mice were substantially larger and more complex, with accelerated cholesterol crystal formation and increased smooth muscle cell content in aortic root lesions. Combined C1q and IgM deficiency had the same effect as IgM deficiency alone. Increased apoptosis was observed in aortic root lesions of both

sIgM.Ldlr
−/−

and

C1qa.Ldlr
−/−

mice. Because lesions were significantly larger in IgM-deficient mice than in the absence of C1q, IgM protective mechanisms appear to be partially independent of classical pathway activation and apoptotic cell clearance. Levels of IgG antibodies against copper-oxidized LDL were lower in

sIgM.Ldlr
−/−

mice fed a high-fat diet, suggesting compensatory consumption of IgG in the absence of IgM.

Conclusions—

This study provides direct evidence that IgM antibodies play a central role in protection against atherosclerosis. The mechanism appears to be at least partly independent of classical pathway complement activation by C1q.
Dissection of Chromosome 18 Blood Pressure and Salt-Sensitivity Quantitative Trait Loci in the Spontaneously Hypertensive Rat
Authors: Johnson Michelle D. , He Liqun , Herman Daniel , Wakimoto Hiroko , Wallace Caroline A. , Zidek Vaclav , Mlejnek Petr , Musilova Alena , Simakova Miroslava , Vorlicek Jaroslav , Kren Vladimir , Viklicky Ondrej , Qi Nathan R. , Wang Jiaming , Seidman Christine E. , Seidman Jonathan , Kurtz Theodore W. , Aitman Timothy J. , Pravenec Michal
Published: July 2009

Hypertension in humans and experimental models has a strong hereditary basis, but identification of causative genes remains challenging. Quantitative trait loci (QTLs) for hypertension and salt sensitivity have been reported on rat chromosome 18. We set out to genetically isolate and prioritize genes within the salt-sensitivity and hypertension QTLs on the spontaneously hypertensive rat (SHR) chromosome 18 by developing and characterizing a series of congenic strains derived from the SHR and normotensive Brown Norway rat strains. The SHR.BN-
D18Rat113/D18Rat82
congenic strain exhibits significantly lower blood pressure and is salt resistant compared with the SHR. Transplantation of kidneys from SHR.BN-
D18Rat113/D18Rat82
donors into SHR recipients is sufficient to attenuate increased blood pressure but not salt sensitivity. Derivation of congenic sublines allowed for the separation of salt sensitivity from hypertension QTL regions. Renal expression studies with microarray and Solexa-based sequencing in parental and congenic strains identified 4 differentially expressed genes within the hypertension QTL region, one of which is an unannotated transcript encoding a previously undescribed, small, nonprotein coding RNA. Sequencing selected biological candidate genes within the minimal congenic interval revealed a nonsynonymous variant in SHR transcription factor 4. The minimal congenic interval is syntenic to a region of human chromosome 18 where significant linkage to hypertension was observed in family based linkage studies. These congenic lines provide reagents for identifying causative genes that underlie the chromosome 18 SHR QTLs for hypertension and salt sensitivity. Candidate genes identified in these studies merit further investigation as potentially causative hypertension genes in SHR and human hypertension.
Insights Into the Mechanisms and Mediators of the Effects of Air Pollution Exposure on Blood Pressure and Vascular Function in Healthy Humans
Authors: Brook Robert D. , Urch Bruce , Dvonch J. Timothy , Bard Robert L. , Speck Mary , Keeler Gerald , Morishita Masako , Marsik Frank J. , Kamal Ali S. , Kaciroti Niko , Harkema Jack , Corey Paul , Silverman Frances , Gold Diane R. , Wellenius Greg , Mittleman Murray A. , Rajagopalan Sanjay , Brook Jeffrey R.
Published: July 2009

Fine particulate matter air pollution plus ozone impairs vascular function and raises diastolic blood pressure. We aimed to determine the mechanism and air pollutant responsible. The effects of pollution on heart rate variability, blood pressure, biomarkers, and brachial flow-mediated dilatation were determined in 2 randomized, double-blind, crossover studies. In Ann Arbor, 50 subjects were exposed to fine particles (150 μg/m
3
) plus ozone (120 parts per billion) for 2 hours on 3 occasions with pretreatments of an endothelin antagonist (Bosentan, 250 mg), antioxidant (Vitamin C, 2 g), or placebo. In Toronto, 31 subjects were exposed to 4 different conditions (particles plus ozone, particles, ozone, and filtered air). In Toronto, diastolic blood pressure significantly increased (2.9 and 3.6 mm Hg) only during particle-containing exposures in association with particulate matter concentration and reductions in heart rate variability. Flow-mediated dilatation significantly decreased (2.0% and 2.9%) only 24 hours after particle-containing exposures in association with particulate matter concentration and increases in blood tumor necrosis factor α. In Ann Arbor, diastolic blood pressure significantly similarly increased during all of the exposures (2.5 to 4.0 mm Hg), a response not mitigated by pretreatments. Flow-mediated dilatation remained unaltered. Particulate matter, not ozone, was responsible for increasing diastolic blood pressure during air pollution inhalation, most plausibly by instigating acute autonomic imbalance. Only particles from urban Toronto additionally impaired endothelial function, likely via slower proinflammatory pathways. Our findings demonstrate credible mechanisms whereby fine particulate matter could trigger acute cardiovascular events and that aspects of exposure location may be an important determinant of the health consequences.
Role of Mineralocorticoid Receptor on Experimental Cerebral Aneurysms in Rats
Authors: Tada Yoshiteru , Kitazato Keiko T. , Tamura Tetsuya , Yagi Kenji , Shimada Kenji , Kinouchi Tomoya , Satomi Junichiro , Nagahiro Shinji
Published: July 2009

Activation of the renin-angiotensin (Ang)-aldosterone system is involved in the pathology of vascular diseases. Although the blockade of the mineralocorticoid receptor protects against vascular diseases, its role in cerebral aneurysms remains to be elucidated. We treated female rats subjected to renal hypertension, increased hemodynamic stress, and estrogen deficiency for 3 months with the mineralocorticoid receptor blocker eplerenone (30 or 100 mg/kg per day) or vehicle (vehicle control). Eplerenone reduced the incidence of cerebral aneurysms and saline intake without lowering of the blood pressure. In the aneurysmal wall, the production of Ang II and nitrotyrosine was increased. The mRNA levels of Ang-converting enzyme 1 and NADPH oxidase subunits NOX4, Rac1, monocyte chemoattractant protein 1, and matrix metalloproteinase 9 were increased. Eplerenone brought about a reduction in these molecules, suggesting that mineralocorticoid receptor blockade suppresses cerebral aneurysm formation by inhibiting oxidative stress, inflammatory factors, local renin-Ang system activation, and saline intake. Other female rats implanted with pellets of the mineralocorticoid receptor agonist deoxycorticosterone acetate manifested a high incidence of cerebral aneurysm formation and the upregulation of molecules related to oxidative stress, inflammatory factors, and the local renin-Ang system; their saline intake was increased. We demonstrate that mineralocorticoid receptor activation at least partly contributes to the pathogenesis of cerebral aneurysms.
Old habits die hard: Mouse handling by a pitviper species on a rodent-free island
Authors: Sazima Ivan , Marques Otavio
Published: July 2009

The golden lancehead (Bothrops insularis) is endemic to Queimada Grande Island off the coast of southeastern Brazil. This pitviper feeds mainly on migratory birds, whereas mainland pitvipers in the genus Bothrops usually feed on rodents. Rodents are regarded as a dangerous prey type, and the habitual handling of rodents by pitvipers include its immediate release after the initial bite. However, bird prey is usually held within jaws after the initial bite. Presently there are no rodents in Queimada Grande Island, which is thought to have isolated from the mainland 11 000 yr ago. We staged encounters between B. insularis and house mice in the field to evaluate how the snake will behave when introduced to a supposedly unknown prey type. Mice were readily accepted as prey and the predatory behaviour of B. insularis was similar to that displayed by mainland pitvipers (strike-release). Although B. insularis has several morphological and ecological particularities that likely developed during its isolation on an island (some of these related to a specialized diet and/or arboreal habits), the handling behaviour of potentially dangerous prey such as rodents was retained – an indication of phylogenetic conservatism.
The reproduction of the Apennine yellow-bellied toad (Bombina pachypus) in central Italy
Authors: Venchi Alberto , Melletti Mario , Mirabile Marzia , Bologna Marco
Published: July 2009

Amphibians are declining worldwide and many species are threatened for unknown reasons. In fact, information on ecology of several species are not available due to the lack of studies. The Apennine yellow-bellied toad (Bombina pachypus) is an Italian endemic species in progressive decline in many areas, often for unclear reasons. A two-year study of 116 temporary ponds in a grazing area of the Majella National Park (central Italy) from 2001 to 2002 revealed that: (a) Apennine yellow-bellied toads reproduced in small ponds characterized by high desiccation risk; (b) breeding activity occurred for a prolonged period (at least from May to the beginning of August), during which females spawned clutches of very few eggs in several, successive events; (c) the reproductive success was very low especially because of high egg mortality; and (d) the main cause of mortality was the desiccation of ponds. Consequently, the characteristics of breeding areas (i.e., small, ephemeral ponds) are the most important feature influencing the reproduction. The safeguard of temporary ponds is crucial for the conservation of this amphibian and could preserve also the other species using these pools.
Sexual dimorphism in the Italian endemic species Salamandrina perspicillata (Savi, 1821) and testing of a field method for sexing salamanders
Authors: Paoletti Carlo , Bruni Giacomo , Romano Antonio
Published: July 2009

Salamandrina perspicillata is an endemic Italian salamander in which morphological sexual dimorphism is weak and sexes are almost indistinguishable in live specimens. We here report on a simple method for sexing these salamanders in the field on the basis of cloacal morphology and we present new data on the sexual dimorphism in this species. Nine morphological characters were used to assess the amount of sexual dimorphism using a multivariate approach (Mancova: Wilks' λ = 0.248, P < 0.001). Sexes differed significantly in both size (females are larger than males) and shape (females have proportionally longer distance between extremities, males have longer cloacal slit and wider head). The observed pattern of sexual dimorphism is discussed in an evolutionary context. Difference between sexes in the proportion of the V-shaped patch on the head was also tested. Finally, we also report the first preliminary data on the sex ratio of a S. perspicillata population in the wild.