bluuebunny/crossref_metadata_2025 huggingface dataset:
INTERTWINING VERTEX OPERATORS AND CERTAIN REPRESENTATIONS OF $\widehat{\mathfrak{sl}(n)}$
Authors: CALINESCU CORINA
Published: February 2008

We study the principal subspaces, introduced by Feigin and Stoyanovsky, of the level 1 standard modules for [Formula: see text] with l ≥ 2. In this paper, we construct exact sequences which give us a complete set of recursions that characterize the graded dimensions of the principal subspaces of these representations. This problem can be viewed as a continuation of a new program to obtain Rogers–Ramanujan-type recursions, which was initiated by Capparelli, Lepowsky and Milas. In order to prove the exactness of the sequences, we use intertwining vertex operators and we supply a proof of the completeness of a list of relations for the principal subspaces. By solving these recursions we recover the graded dimensions of the principal subspaces, previously obtained by Georgiev using a different method.
WAVE-PARTICLE DUALITY IN MULTI-PATH INTERFEROMETERS: GENERAL CONCEPTS AND THREE-PATH INTERFEROMETERS
Authors: ENGLERT BERTHOLD-GEORG , KASZLIKOWSKI DAGOMIR , KWEK LEONG CHUAN , CHEE WEI HUI
Published: February 2008

For two-path interferometers, the which-path predictability [Formula: see text] and the fringe visibility [Formula: see text] are familiar quantities that are much used to talk about wave-particle duality in a quantitative way. We discuss several candidates that suggest themselves as generalizations P of [Formula: see text] for multi-path interferometers, and treat the case of three paths in considerable detail. To each choice for the path knowledge P, the interference strength V — the corresponding generalization of [Formula: see text] — is found by a natural, operational procedure. In experimental terms, it amounts to finding those equal-weight superpositions of the path amplitudes which maximize P for the emerging intensities. Mathematically speaking, one needs to identify a certain optimum one among the Fourier transforms of the state of the interfering quantum object. Wave-particle duality is manifest, inasmuch as P = 1 implies V = 0 and V = 1 implies P = 0, whatever definition is chosen. The possible values of the pair (P,V) are restricted to an area with corners at (P,V) = (0,0), (P,V) = (1,0), and (P,V) = (0,1), with the shape of the border line from (1,0) to (0,1), depending on the particular choice for P and the induced definition of V.
SECURITY OF QUANTUM KEY DISTRIBUTION
Authors: RENNER RENATO
Published: February 2008

Quantum Information Theory is an area of physics which studies both fundamental and applied issues in quantum mechanics from an information-theoretical viewpoint. The underlying techniques are, however, often restricted to the analysis of systems which satisfy a certain independence condition. For example, it is assumed that an experiment can be repeated independently many times or that a large physical system consists of many virtually independent parts. Unfortunately, such assumptions are not always justified. This is particularly the case for practical applications — e.g. in quantum cryptography — where parts of a system might have an arbitrary and unknown behavior.

We propose an approach which allows us to study general physical systems for which the above mentioned independence condition does not necessarily hold. It is based on an extension of various information-theoretical notions. For example, we introduce new uncertainty measures, called smooth min- and max-entropy, which are generalizations of the von Neumann entropy. Furthermore, we develop a quantum version of de Finetti's representation theorem, as described below.

Consider a physical system consisting of n parts. These might, for instance, be the outcomes of n runs of a physical experiment. Moreover, we assume that the joint state of this n-partite system can be extended to an (n + k)-partite state which is symmetric under permutations of its parts (for some k ≫ 1). The de Finetti representation theorem then says that the original n-partite state is, in a certain sense, close to a mixture of product states. Independence thus follows (approximatively) from a symmetry condition. This symmetry condition can easily be met in many natural situations. For example, it holds for the joint state of n parts, which are chosen at random from an arbitrary (n + k)-partite system.

As an application of these techniques, we prove the security of quantum key distribution (QKD), i.e. secret key agreement by communication over a quantum channel. In particular, we show that, in order to analyze QKD protocols, it is generally sufficient to consider so-called collective attacks, where the adversary is restricted to applying the same operation to each particle sent over the quantum channel separately. The proof is generic and thus applies to known protocols such as BB84 and B92 (where better bounds on the secret-key rate and on the the maximum tolerated noise level of the quantum channel are obtained) as well as to continuous variable schemes (where no full security proof has been known). Furthermore, the security holds with respect to a strong so-called universally composable definition. This implies that the keys generated by a QKD protocol can safely be used in any application, e.g. for one-time pad encryption — which, remarkably, is not the case for most standard definitions.
INFLUENCE OF INTRINSIC DECOHERENCE ON THE ENTANGLEMENT BETWEEN TWO ATOMS IN TAVIS–CUMMINGS MODEL
Authors: SHAN CHUAN-JIA , CHENG WEI-WEN , LIU TANG-KUN , HUANG YAN-XIA , LI HONG , XIA YUN-JIE
Published: February 2008

Considering the dipole–dipole coupling intensity between two atoms and the field in the Fock state, the entanglement dynamics between two atoms that are initially entangled in the Tavis–Cummings model with intrinsic decoherence have been investigated. The two-atom entanglement appears with periodicity without considering intrinsic decoherence. However, the intrinsic decoherence causes the decay of entanglement between two atoms, with the decrease of the intrinsic decoherence coefficient, the entanglement will quickly become a constant value, which is affected by the two-atom initial state, the dipole–dipole coupling intensity and the field in the Fock state. Meanwhile, the two-atom quantum state will stay forever in the maximal entangled state when the initial state is proper, even in the presence of intrinsic decoherence. Furthermore, the two atoms can generate maximal entangled state even if they are initially separated by adjusting the dipole–dipole interaction, the strong coupling can improve the value of entanglement.
ENTANGLEMENT ENTROPY: HELICITY VERSUS SPIN
Authors: HE SONG , SHAO SHUXIN , ZHANG HONGBAO
Published: February 2008

For a massive spin 1/2 field, we present the reduced spin and helicity density matrix, respectively, for the same pure one particle state. Their relation has also been developed. Furthermore, we calculate and compare the corresponding entanglement entropy for spin and helicity within the same inertial reference frame. Due to the distinct dependence on momentum degree of freedom between spin and helicity states, the resultant helicity entropy is different from that of spin in general. In particular, we find that both helicity entanglement for a spin eigenstate and spin entanglement for a right handed or left handed helicity state do not vanish, and their Von Neumann entropy has no dependence on the specific form of momentum distribution, as long as it is isotropic.
NEW ASPECTS OF THE PURITY AND INFORMATION OF AN ENTANGLED QUBIT PAIR
Authors: METWALLY NASSER
Published: February 2008

In this article, we investigate the purity dynamics of entangled 2 two-level atoms interacting with a single quantized electromagnetic field. We show that the purity of the qubit pairs depends on the initial state of the atomic system. It is found that the superposition case is the best choice to generate entangled states with high purity and hence high entanglement. It is clear that the purity of one qubit can be purified at the expense of the other pair through the phenomena of purity swapping. The mean photon number plays an important role in increasing the purity. The robustness of the quantum channel is investigated in the presence of individual attacks, where we study the separability of these channels and evaluate its fidelity. Finally, we use the partial entangled states as quantum channels to perform the original coding protocol. We find that Bob can obtain the coded information with reasonable percentage. The inequality of security is tested, where we determine the interval of times in which Alice and Bob can communicate securely. These intervals depend on the type of error and the structure of the initial atomic system.
Crowding Effects on Diffusion in Solutions and Cells
Authors: Dix James A. , Verkman A.S.
Published: February 2008

We review the effects of molecular crowding on solute diffusion in solution and in cellular aqueous compartments and membranes. Anomalous diffusion, in which mean squared displacement does not increase linearly with time, is predicted in simulations of solute diffusion in media crowded with fixed or mobile obstacles, or when solute diffusion is restricted or accelerated by a variety of geometric or active transport processes. Experimental measurements of solute diffusion in solutions and cellular aqueous compartments, however, generally show Brownian diffusion. In cell membranes, there are examples of both Brownian and anomalous diffusion, with the latter likely produced by lipid-protein and protein-protein interactions. We conclude that the notion of universally anomalous diffusion in cells as a consequence of molecular crowding is not correct and that slowing of diffusion in cells is less marked than has been generally assumed.
Intrinsically Disordered Proteins in Human Diseases: Introducing the D2Concept
Authors: Uversky Vladimir N. , Oldfield Christopher J. , Dunker A. Keith
Published: February 2008

Intrinsically disordered proteins (IDPs) lack stable tertiary and/or secondary structures under physiological conditions in vitro. They are highly abundant in nature and their functional repertoire complements the functions of ordered proteins. IDPs are involved in regulation, signaling, and control, where binding to multiple partners and high-specificity/low-affinity interactions play a crucial role. Functions of IDPs are tuned via alternative splicing and posttranslational modifications. Intrinsic disorder is a unique structural feature that enables IDPs to participate in both one-to-many and many-to-one signaling. Numerous IDPs are associated with human diseases, including cancer, cardiovascular disease, amyloidoses, neurodegenerative diseases, and diabetes. Overall, intriguing interconnections among intrinsic disorder, cell signaling, and human diseases suggest that protein conformational diseases may result not only from protein misfolding, but also from misidentification, missignaling, and unnatural or nonnative folding. IDPs, such as α-synuclein, tau protein, p53, and BRCA1, are attractive targets for drugs modulating protein-protein interactions. From these and other examples, novel strategies for drug discovery based on IDPs have been developed. To summarize work in this area, we are introducing the D2(disorder in disorders) concept.
Coastal Impacts Due to Sea-Level Rise
Authors: FitzGerald Duncan M. , Fenster Michael S. , Argow Britt A. , Buynevich Ilya V.
Published: February 2008

The Intergovernmental Panel on Climate Change (2007) recently estimated that global sea level will rise from 0.18 to 0.59 m by the end of this century. Rising sea level not only inundates low-lying coastal regions but also contributes to the redistribution of sediment along sandy coasts. Over the long term, sea-level rise (SLR) causes barrier islands to migrate landward while conserving mass through offshore and onshore sediment transport. Under these conditions, coastal systems adjust to SLR dynamically while maintaining a characteristic geometry that is unique to a particular coast. Coastal marshes are susceptible to accelerated SLR because their vertical accretion rates are limited and they may drown. As marshes convert to open water, tidal exchange through inlets increases, which leads to sand sequestration in tidal deltas and erosion of adjacent barrier shorelines.
On the Generalized Hyers-Ulam Stability of a Cauchy-Jensen Functional Equation
Authors: Jun Kil-Woung , Lee Yang-Hi , Cho Young-Sun
Published: February 2008

In 2006, W. G. Park and J. H. Bae investigated the Hyers-Ulam stability of a Cauchy-Jensen functional equation. In this paper, we improve their results and obtain better results for a Cauchy-Jensen functional equation. Also, we establish new theorems for the generalized Hyers-Ulam stability of a Cauchy-Jensen functional equation.
Monotonicity of Harnack Inequality for Positive Invariant Harmonic Functions
Authors: Pan Yifei , Wang Mei
Published: February 2008

A monotonicity property and a refined estimate of Harnack inequality are derived for positive solutions of the Weinstein equation.
On the Recursive Sequencexn+1=A+xnp/xn−1r
Authors: Stevic Stevo
Published: February 2008

The paper considers the boundedness character of positive solutions of the difference equationxn+1=A+xnp/xn−1r,n∈ℕ0, whereA,p, andrare positive real numbers. It is shown that (a) Ifp2≥4r>4, orp≥1+r,r≤1, then this equation has positive unbounded solutions; (b) ifp2<4r, or2r≤p<1+r,r∈(0,1), then all positive solutions of the equation are bounded. Also, an analogous result is proved regarding positive solutions of the max type difference equationxn+1=max{A,xnp/xn−1r}, whereA,p,q∈(0,∞).
Harvesting Control for a Stage-Structured Predator-Prey Model with Ivlev's Functional Response and Impulsive Stocking on Prey
Authors: Liu Kaiyuan , Chen Lansun
Published: February 2008

We investigate a delayed stage-structured Ivlev's functional response predator-prey model with impulsive stocking on prey and continuous harvesting on predator. Sufficient conditions of the global attractivity of predator-extinction periodic solution and the permanence of the system are obtained. These results show that the behavior of impulsive stocking on prey plays an important role for the permanence of the system. We also prove that all solutions of the system are uniformly ultimately bounded. Our results provide reliable tactical basis for the biological resource management and enrich the theory of impulsive delay differential equations.
Cone‐Beam Composite‐Circling Scan and Exact Image Reconstruction for a Quasi‐Short Object
Authors: Yu Hengyong , Wang Ge
Published: February 2008

Here we propose a cone‐beam composite‐circling mode to solve the quasi‐short object problem, which is to reconstruct a short portion of a long object from longitudinally truncated cone‐beam data involving the short object. In contrast to the saddle curve cone‐beam scanning, the proposed scanning mode requires that the X‐ray focal spot undergoes a circular motion in a plane facing the short object, while the X‐ray source is rotated in the gantry main plane. Because of the symmetry of the proposed mechanical rotations and the compatibility with the physiological conditions, this new mode has significant advantages over the saddle curve from perspectives of both engineering implementation and clinical applications. As a feasibility study, a backprojection filtration (BPF) algorithm is developed to reconstruct images from data collected along a composite‐circling trajectory. The initial simulation results demonstrate the correctness of the proposed exact reconstruction method and the merits of the proposed mode.
Species Diversity Enhances Predator Growth Rates
Authors: Olson Mark H. , Jacobs Robert P. , O'Donnell Eileen B.
Published: February 2008

Predators can be important top-down regulators of community structure and are known to have both positive and negative effects on species diversity. However, little is known about the reciprocal effects of species diversity on predators. Across a set of 80 lakes in Connecticut, USA, we found a strong positive correlation between prey species diversity (using the Shannon-Weiner Diversity Index) and growth rates of largemouth bass (Micropterus salmoides). This correlation was strongest for small predators and decreased with body size. Although the underlying mechanisms are not known, the correlation is not driven by total fish abundance, predator abundance, or productivity.
Parametric Study of Ultra‐Wideband Dual Elliptically Tapered Antipodal Slot Antenna
Authors: Qing Xianming , Chen Zhi Ning , Chia Michael Yan Wah
Published: February 2008

Parametric study of the impedance and radiation characteristics of a dual elliptically tapered antipodal slot antenna (DETASA) is undertaken in this paper. Usually, the performance of the DETASA is sensitive to the parameters, the effects of major geometry parameters of the radiators and feeding transition of the DETASA on antenna performance are investigated across the frequency range of 1–18 GHz. The information derived from this study provides guidelines for the design and optimization of the DETASAs which are widely used for UWB applications.
Correlation of DNA Ploidy with Progression of Cervical Cancer
Authors: Singh M. , Mehrotra S. , Kalra N. , Singh U. , Shukla Y.
Published: February 2008

The majority of squamous cell carcinomas of cervix are preceded by visible changes in the cervix, most often detected by cervical smear. As cervical cancer is preceded by long precancerous stages, identification of the high-risk population through detection of DNA ploidy may be of importance in effective management of this disease. Here we attempted to correlate aneuploid DNA patterns and their influence on biological behavior of flow-cytometry analysis of DNA ploidy which was carried out in cytologically diagnosed cases of mild (79), moderate (36), and severe (12) dysplasia, as well as “atypical squamous cells of unknown significance (ASCUS)” (57) along with controls (69), in order to understand its importance in malignant progression of disease. Cytologically diagnosed dysplasias, which were employed for DNA ploidy studies, 39 mild, 28 moderate, and 11 severe dysplasia cases were found to be aneuploid. Out of the 69 control subjects, 6 cases showed aneuploidy pattern and the rest 63 subjects were diploid. An aneuploidy pattern was observed in 8 out of 57 cases of cytologically evaluated ASCUS. The results of the followup studies showed that aberrant DNA content reliably predicts the occurrence of squamous cell carcinoma in cervical smear. Flow cytometric analysis of DNA ploidy may provide a strategic diagnostic tool for early detection of carcinoma cervix. Therefore, it is a concept of an HPV screening with reflex cytology in combination with DNA flow cytometry to detect progressive lesions with the greatest possible sensitivity and specificity.
Peroxisome Proliferator‐Activated Receptor and Age‐Related Macular Degeneration
Authors: Herzlich Alexandra A. , Tuo Jingsheng , Chan Chi-Chao
Published: February 2008

Age‐related macular degeneration (AMD) is the leading cause
of new blindness in the western world and is becoming more of
a socio‐medical problem as the proportion of the aged
population increases. There are multiple efforts underway to
better understand this disease process. AMD involves the
abnormal retinal pigment epithelium (RPE), drusen formation,
photoreceptor atrophy, and choroidal neovascularization.
Peroxisome proliferator‐activated receptors (PPARs) play an
important role in lipid degeneration, immune regulation,
regulation of reactive oxygen species (ROSs), as well as
regulation of vascular endothelial growth factor (VEGF),
matrix metalloproteinase‐9 (MMP‐9), and
docosahexaenoic acid (DHA). These molecules have all been
implicated in the pathogenesis of AMD. In addition, PPAR
gamma is expressed in RPE, an essential cell in photoreceptor
regeneration and vision maintenance. This review summarizes
the interactions between PPAR, AMD‐related molecules, and
AMD‐related disease processes.
UWB Directive Triangular Patch Antenna
Authors: Lepage A. C. , Begaud X. , Le Ray G. , Sharaiha A.
Published: February 2008

Compact directive UWB antennas are presented in this paper. We propose an optimization of the F‐probe fed triangular patch antenna. The new design achieves an impedance bandwidth of 69% (3–6.15 GHz) and presents good radiation characteristics over the whole impedance bandwidth. The average gain is 6.1 dB. A time‐domain study has been performed to characterize the antenna behavior in case a UWB pulse is used. Finally, we propose an alternative solution to facilitate the manufacturing process using metallized foam technology. It also improves the robustness of the antenna as well as reducing its cost.
Rough Sets Data Analysis in Knowledge Discovery: A Case of Kuwaiti Diabetic Children Patients
Authors: Hassanien Aboul ella , Abdelhafez Mohamed E. , Own Hala S.
Published: February 2008

The main goal of this study is to investigate the relationship between psychosocial variables and diabetic children patients and to obtain a classifier function with which it was possible to classify the patients on the basis of assessed adherence level. The rough set theory is used to identify the most important attributes and to induce decision rules from 302 samples of Kuwaiti diabetic children patients aged 7–13 years old. To increase the efficiency of the classification process, rough sets with Boolean reasoning discretization algorithm is introduced to discretize the data, then the rough set reduction technique is applied to find all reducts of the data which contains the minimal subset of attributes that are associated with a class label for classification. Finally, the rough sets dependency rules are generated directly from all generated reducts. Rough confusion matrix is used to evaluate the performance of the predicted reducts and classes. A comparison between the obtained results using rough sets with decision tree, neural networks, and statistical discriminate analysis classifier algorithms has been made. Rough sets show a higher overall accuracy rates and generate more compact rules.
Optimal Multilayer Adaptation of SVC Video over Heterogeneous Environments
Authors: Thang Truong Cong , Kang Jung Won , Yoo Jeong-Ju , Ro Yong Man
Published: February 2008

Scalable video coding (SVC) is a new video coding format which provides scalability in three‐dimensional (spatio‐temporal‐SNR) space. In this paper, we focus on the adaptation in SNR dimension. Usually, an SVC bitstream may contain multiple spatial layers, and each spatial layer may be enhanced by several FGS layers. To meet a bitrate constraint, the fine‐grained scalability (FGS) data of different spatial layers can be truncated in various manners. However, the contributions of FGS layers to the overall/collective video quality are different. In this work, we propose an optimized framework to control the SNR scalability across multiple spatial layers. Our proposed framework has the flexibility in allocating the resource (i.e., bitrate) among spatial layers, where the overall quality is defined as a function of all spatial layers′ qualities and can be modified on the fly.
Should We Use PPAR Agonists to Reduce Cardiovascular Risk?
Authors: Robinson Jennifer G.
Published: February 2008

Trials of peroxisome proliferator‐activated receptor (PPAR) agonists have shown mixed results for cardiovascular prevention. Fibrates are PPAR‐α agonists that act primarily to improve dyslipidemia. Based on low‐ and high‐density
lipoprotein cholesterol (LDL and HDL) effects, gemfibrozil may be of greater cardiovascular benefit than expected, fenofibrate performed about as expected, and bezafibrate performed worse than expected. Increases in both cardiovascular and noncardiovascular serious adverse events have been observed with some fibrates. Thiazolidinediones (TZDs) are PPAR‐γ agonists used to improve impaired glucose metabolism but also influence lipids.
Pioglitazone reduces atherosclerotic events in diabetic subjects, but has no net cardiovascular benefit due to increased congestive heart failure risk. Rosiglitazone may increase the risk of atherosclerotic events, and has a net harmful effect on the cardiovascular system when congestive heart failure is included. The primary benefit of TZDs appears to be the prevention of diabetic microvascular complications. Dual PPAR‐α/γ agonists have had unacceptable adverse effects but more selective agents are in development. PPAR‐δ and pan‐agonists are also in development. It will be imperative to prove that future PPAR agonists not only prevent atherosclerotic events but also result in a net reduction on total cardiovascular events without significant noncardiovascular adverse effects with long‐term use.
Eosinophilic Esophagitis and Barrett’s Esophagus: An Occasional Association or an Overlap Disease?
Authors: Francalanci Paola , De Angelis Paola , Minnei Francesca , Diomedi Camassei Francesca , Torroni Filippo , Dall’Oglio Luigi , Callea Francesco
Published: February 2008

Background: Esophageal diseases are common in infants and children, and may present with several clinical and pathological aspects. Eosinophilic esophagitis (EE) is characterized by inflammatory, predominantly eosinophilic infiltrate (≧15 eosinophils per high-power field (HPF)) that is not responsive to acid suppression therapy. An immunoallergic pathogenesis has been hypothesized, likely related to food allergy. Barrett’s esophagus (BE) is due to chronic gastroesophageal reflux. The pathological consequence is the replacement of normal stratified squamous epithelium by columnar mucosa with goblet cells. Methods: We present 2 children with a history of food allergy. Endoscopy revealed linear furrows and yellow plaques in the mid-distal esophagus. Results: In both patients histology showed a high number of eosinophils (>30 at HPF) in the mid-distal esophagus and intestinal metaplasia with goblet cells in distal esophagus. Diagnosis of EE associated to BE was made. Restriction diet was administered to treat EE whereas, in 1 case, laparoscopic fundoplication was performed to treat BE. Follow-up showed a remission of endoscopic and histological aspects. Conclusions: The unusual, possibly fortuitous association of EE and BE, two conditions differing in etiopathogenesis, clinical and pathological features, calls for a correct diagnosis to offer suitable treatment and prognosis.
Interactions of MRZ 2/576 with Felbamate, Lamotrigine, Oxcarbazepine and Topiramate in the Mouse Maximal Electroshock-Induced Seizure Model
Authors: Luszczki Jarogniew J. , Danysz Wojciech , Czuczwar Stanislaw J.
Published: February 2008

This study focused on the evaluation of interactions between MRZ 2/576 (8-chloro-4-hydroxy-1-oxo-1,2-dihydropyridazino(4,5-b)quinoline-5-oxide choline salt), an N-methyl-D-aspartate (NMDA) receptor antagonist acting at the NMDA receptor/glycineB site and four newer antiepileptic drugs (felbamate, lamotrigine, oxcarbazepine, and topiramate) in the mouse maximal electroshock seizure model. Results indicate that MRZ 2/576 administered intraperitoneally, 5 min before the test, exerted a clear-cut anticonvulsant effect in the maximal electroshock seizure test in mice and its ED50 value was 13.71 (11.95–15.73) mg/kg. In the subthreshold method, MRZ 2/576 (administered intraperitoneally, at a subthreshold dose of 5 mg/kg) significantly enhanced the anticonvulsant action of felbamate, oxcarbazepine and topiramate, by reducing their ED50 values from 73.0 to 53.8 mg/kg (p < 0.05) for felbamate, from 10.77 to 7.48 mg/kg (p < 0.05) for oxcarbazepine, and from 49.3 to 28.7 mg/kg (p < 0.01) for topiramate. In contrast, MRZ 2/576 (5 mg/kg, i.p.) did not significantly affect the antiseizure effects of lamotrigine in the maximal electroshock seizure test in mice. Isobolographic transformation of data revealed that MRZ 2/576 (5 mg/kg, i.p.) exerted barely additive interactions with all investigated antiepileptic drugs in the maximal electroshock seizure test. In conclusion, the isobolographic analysis revealed that MRZ 2/576 additively cooperates with newer antiepileptic drugs in terms of suppression of maximal electroshock-induced seizures in mice.
S-Adenosylhomocysteine Hydrolase from Corynebacterium glutamicum: Cloning, Overexpression, Purification, and Biochemical Characterization
Authors: Lozada-Ramírez J.D. , Martínez-Martínez I. , Sánchez-Ferrer A. , García-Carmona F.
Published: February 2008

The S-adenosylhomocysteine hydrolase gene (sahase) was cloned from the Gram-positive soil bacterium Corynebacterium glutamicum (ATCC 13032) and sequenced. The sahase gene possesses an open reading frame, which consists of 1,434 nucleotides that encode 478 amino acids. The sahase gene from C. glutamicum was expressed in Escherichia coli Rosetta cells by inserting the 1,434-bp fragment downstream from the isopropyl-β-D-thiogalactopyranoside-inducible promoter of the pET28a+ expression vector. The recombinant S-adenosylhomocysteine hydrolase from C. glutamicum (CgrSAHase) was purified efficiently by a two-step procedure, tangential ultrafiltration and affinity chromatography. The molecular weight of the CgrSAHase, estimated by gel filtration, was about 210 kDa, while sodium dodecyl sulfate polyacrylamide gel electrophoresis yielded a relative molecular mass of 52 ± 1 kDa. The Michaelis-Menten constants for the natural substrates of the enzyme, S-adenosylhomocysteine (SAH), adenosine, and homocysteine, were determined to be 12, 1.4, and 40 µM, respectively. The overexpression of CgrSAHase was achieved at high level (>40 mg protein/g wet cells). Because of its high capacity to synthesize SAH, this enzyme is of high biotechnological interest.
Prediction of the Localization of High-Risk Coronary Atherosclerotic Plaques on the Basis of Low Endothelial Shear Stress
Authors: Chatzizisis Yiannis S. , Jonas Michael , Coskun Ahmet U. , Beigel Roy , Stone Benjamin V. , Maynard Charles , Gerrity Ross G. , Daley William , Rogers Campbell , Edelman Elazer R. , Feldman Charles L. , Stone Peter H.
Published: February 2008

Background—

Low endothelial shear stress (ESS) promotes the development of atherosclerosis; however, its role in the progression of atherosclerotic plaques and evolution to inflamed high-risk plaques has not been studied. Our hypothesis was that the lowest values of ESS are responsible for the development of high-risk coronary atherosclerotic plaques associated with excessive expansive remodeling.

Methods and Results—

Twenty-four swine, treated with streptozotocin to induce diabetes and fed a high-fat diet, were allocated into early (n=12) and late (n=12) atherosclerosis groups. Intima-media thickness was assessed by intravascular ultrasound in the coronary arteries at weeks 4 and 8 in the early group and weeks 23 and 30 in the late group. Plaques started to develop after week 8, leading to marked heterogeneity in plaque severity at week 30. ESS was calculated in plaque-free subsegments of interest (n=142) in the late group at week 23. Coronary arteries (n=31) of this group were harvested at week 30, and the subsegments of interest were identified and analyzed histopathologically. Low ESS was an independent predictor of the development of high-risk plaques, characterized by intense lipid accumulation, inflammation, thin fibrous cap, severe internal elastic lamina degradation, and excessive expansive remodeling. The severity of high-risk plaque characteristics at week 30 was significantly correlated with the magnitude of low ESS at week 23.

Conclusions—

The magnitude of low ESS determines the complexity and heterogeneity of atherosclerotic lesions and predicts the development of high-risk plaque.
Matrix Metalloproteinase-14 Deficiency in Bone Marrow–Derived Cells Promotes Collagen Accumulation in Mouse Atherosclerotic Plaques
Authors: Schneider Fabrice , Sukhova Galina K. , Aikawa Masanori , Canner James , Gerdes Norbert , Tang Sai-Man Timothy , Shi Guo-Ping , Apte Suneel S. , Libby Peter
Published: February 2008

Background—

Interstitial collagen plays a crucial structural role in arteries. Although in vitro results suggest collagenase activity for membrane-bound matrix metalloproteinase type 1 (MMP-14), in vivo evidence for such a function in atherosclerosis remains scant.

Methods and Results—

Because

Mmp14
−/−

mice die by 3 weeks of age, this study used lethally irradiated low-density lipoprotein receptor–deficient mice reconstituted with syngeneic bone marrow cells of

Mmp14
−/−

or
Mmp14
+/+
mice. In both groups, histological analyses of the aortic root revealed similar plaque size and macrophage and smooth muscle cell content after 8 or 16 weeks of atherogenic diet. By 16 weeks, however, the plaques of low-density lipoprotein receptor–deficient mice engrafted with

Mmp14
−/−

bone marrow (n=12) contained significantly more interstitial collagen than those receiving
Mmp14
+/+
bone marrow (n=14;
P
<0.05). In vitro, bone marrow–derived macrophages from

Mmp14
−/−

mice had significantly less interstitial collagenase activity than those from
Mmp14
+/+
mice both basally (
P
<0.01) and on tumor necrosis factor-α stimulation (
P
<0.05). Western blot analysis and gelatin zymography of aortic extracts revealed that MMP-14 deficiency yielded decreased activation of pro–MMP-13 but not of pro–MMP-2 or pro–MMP-8.

Conclusion—

MMP-14 from bone marrow–derived cells can influence the collagen content of mouse atheroma, a critical component of plaque stability.
A Number of Marketed Dihydropyridine Calcium Channel Blockers Have Mineralocorticoid Receptor Antagonist Activity
Authors: Dietz Jessica D. , Du Sarah , Bolten Charles W. , Payne Maria A. , Xia Chunsheng , Blinn James R. , Funder John W. , Hu Xiao
Published: February 2008

Calcium channel blockers are widely used antihypertensives. Mineralocorticoid receptor antagonists are also used to treat hypertension and heart failure. We report here that a number of widely used dihydropyridine class calcium channel blockers are able to inhibit aldosterone-induced activation of mineralocorticoid receptor. These dihydropyridines varied in the extent of their effect on mineralocorticoid receptor, with nimodipine and felodipine the most potent and amlodipine the least. In contrast, both diltiazem and verapamil, nondihydropyridine calcium channel blockers, had no effect on mineralocorticoid receptor. These dihydropyridines compete with aldosterone for binding and block aldosterone-induced coactivator recruitment to mineralocorticoid receptor. The mineralocorticoid receptor S810L mutant, which is activated by steroidal mineralocorticoid receptor antagonist such as eplerenone, is inhibited by these drugs. Furthermore, nimodipine decreased aldosterone-induced expression of the mineralocorticoid receptor target gene epithelial sodium channel gamma subunit in adrenalectomized rats, demonstrating that dihydropyridine calcium channel blockers can function as mineralocorticoid receptor antagonists in vivo. Molecular modeling indicates that dihydropyridines dock into the ligand binding domain of mineralocorticoid receptor in a consensus pose that partially overlaps with steroidal mineralocorticoid receptor antagonists. Together, our data suggest that, in addition to their calcium channel blocking activity, a number of dihydropyridine calcium channel blockers also have mineralocorticoid receptor antagonist activity at high doses, a finding which may thus prove useful for the design of novel antihypertensive drugs in the future.
Dietary Phosphorus and Blood Pressure
Authors: Elliott Paul , Kesteloot Hugo , Appel Lawrence J. , Dyer Alan R. , Ueshima Hirotsugu , Chan Queenie , Brown Ian J. , Zhao Liancheng , Stamler Jeremiah
Published: February 2008

Raised blood pressure is a leading cause of morbidity and mortality worldwide; improved nutritional approaches to population-wide prevention are required. Few data are available on dietary phosphorus and blood pressure and none are available on possible combined effects of phosphorus, magnesium, and calcium on blood pressure. The International Study of Macro- and Micro-Nutrients and Blood Pressure is a cross-sectional epidemiologic study of 4680 men and women ages 40 to 59 from 17 population samples in Japan, China, United Kingdom, and United States. Blood pressure was measured 8 times at 4 visits. Dietary intakes were obtained from four 24-hour recalls plus data on supplement use. Dietary phosphorus was inversely associated with blood pressure in a series of predefined multiple regression models, with the successive addition of potential confounders, both nondietary and dietary. Estimated blood pressure differences per 232 mg/1000 kcal (2 SD) of higher dietary phosphorus were −1.1 to −2.3 mm Hg systolic/−0.6 to −1.5 mm Hg diastolic (n=4680) and −1.6 to −3.5 mm Hg systolic/−0.8 to −1.8 mm Hg diastolic for 2238 “nonintervened” individuals, ie, those without special diet/nutritional supplements or diagnosis/treatment for cardiovascular disease or diabetes. Dietary calcium and magnesium, correlated with phosphorus (partial
r
=0.71 and
r
=0.68), were inversely associated with blood pressure. Blood pressures were lower by 1.9 to 4.2 mm Hg systolic/1.2 to 2.4 mm Hg diastolic for people with intakes above versus below country-specific medians for all 3 of the minerals. These results indicate the potential for increased phosphorus/mineral intake to lower blood pressure as part of the recommendations for healthier eating patterns for the prevention and control of prehypertension and hypertension.
When Ambiguity in Treaty Design Becomes Destructive: A Study of Transboundary Water
Authors: Fischhendler Itay
Published: February 2008

Ambiguity has a clear role in facilitating closure in negotiations to regulate natural resources. However, there are no empirical studies that examine whether such “constructive ambiguity” can in fact become destructive. The aim of the present study is thus to determine when ambiguity becomes destructive during the management phase of environmental regimes. The implementation of the Israeli-Jordanian water agreement is used as a case study. It was found that when political and hydrological conditions are unstable, the parties see the process of clarifying the ambiguities in a water agreement as broader than simply a question of bilateral relations over resource allocation. As a result, the cost of clarifying ambiguity at the implementation phase dramatically increases. The anatomy of resolving ambiguous agreements teaches us that there are early signs that indicate when ambiguity becomes destructive. Tracing these signals is crucial, since the cost of ambiguity is not linear. Rather, when a disagreement around ambiguity passes a threshold, it can escalate into a conflict in a very short time.
Underneath Kyoto: Emerging Subnational Government Initiatives and Incipient Issue-Bundling Opportunities in China and the United States
Authors: Koehn Peter H.
Published: February 2008

At present, progress in mitigating global GHG emissions is impeded by political stalemate at the national level in the United States and the People's Republic of China. Through the conceptual lenses of multilevel governance and framing politics, the article analyzes emerging policy initiatives among subnational governments in both countries. Effective subnational emission-mitigating action requires framing climatic-stabilization policies in terms of local co-benefits associated with environmental protection, health promotion, and economic advantage. In an impressive group of US states and cities, and increasingly at the local level in China, public concerns about air pollution, consumption and waste management, traffic congestion, health threats, the ability to attract tourists, and/or diminishing resources are legitimizing policy developments that carry the co-benefit of controlling GHG emissions. A co-benefits framing strategy that links individual and community concerns for morbidity, mortality, stress reduction, and healthy human development for all with GHG-emission limitation/reduction is especially likely to resonate powerfully at the subnational level throughout China and the United States.
Business and International Environmental Agreements: Domestic Sources of Participation and Compliance by Advanced Industrialized Democracies
Authors: Bernhagen Patrick
Published: February 2008

This article analyzes the political influence of business in the context of international environmental cooperation. Locating the sources of business power in three distinct factors—organizational strength, structural privilege, and informational advantage—the article evaluates the contributions of these factors to explanations of states' ratification of, and compliance with, international environmental agreements. Using data on 35 advanced industrialized democracies, the results suggest that business influence can be best explained by reference to informational asymmetries. While countries whose economies are exposed to international trade tend to participate less in international regimes, strong domestic environmental movements can counteract incentives for non-participation by providing political decision-makers with alternative information about the costs and benefits of participation. Regime compliance also increases with the availability of independent information through environmental groups, as well as with the degree of politico-economic integration found in neocorporatist systems of interest intermediation.
Life, Movement, and Desire
Authors: Barbaras Renaud
Published: February 2008

In French, the verb "to live" designates both being alive and the experience of something. This ambiguity has a philosophical meaning. The task of a phenomenology of life is to describe an originary sense of living from which the very distinction between life in the intransitive sense and life in the transitive, or intentional, sense proceeds. Hans Jonas is one of those rare authors who has tried to give an account of the specificity of life instead of reducing life to categories that are foreign to it. However, the concept of metabolism, by which Jonas characterizes vital activity, attests to a presupposition as to life: life is conceived as self-preservation, that is, as negation of death, in such a way that life is, in the end, not thought on the basis of itself. The aim of this article is to show that life as such must be understood as movement in a radicalized sense, in which the living being is no more the subject than the product. All living beings are in effect characterized by a movement, which nothing can cause to cease, a movement that largely exceeds what is required by the satisfaction of needs and that, because of this, bears witness to an essential incompleteness. This incompleteness reveals that life is originarily bound to a world. Because the world to which the living being relates is essentially non-totalizable and unpresentable, living movement can not essentially complete itself. Thus, in the final analysis, life must be defined as desire, and in virtue of this view, life does not tend toward self-preservation, as we have almost always thought, but toward the manifestation of the world.
'Art' in Nancy's 'First Philosophy': The Artwork and the Praxis of Sense Making
Authors: Ross Alison
Published: February 2008

For the purposes of analytical clarity it is possible to distinguish two ways in which Nancy's ontology of sense appeals to art. First, he uses 'art' as a metaphorical operator to give features to his ontology (such as surprise and wonder); second, the practice of the contemporary arts instruct the terms of his ontological project because, in his view, this practice catches up with the fragmentation of existence and thus informs ontology about the structure of existence today. These two different roles—in which 'art' is both a general category able to stage the features of sense in general and a particularly striking example of the alteration sense undergoes in our times—make available for Nancy different perspectives on the question of sense. On the one hand, the general category of 'art' allows Nancy to construct a characterology of sense around terms such as surprise and novelty; on the other, the appeal to the fractal practice of the 'contemporary arts' supports the project of giving an account of sense.This paper analyses the effects on Nancy's conception of sense of these different appeals to 'art' and the practice of 'the contemporary arts.' Are the locales from which these different perspectives on sense take shape compatible? In what ways do they inflect each other or, alternatively, undermine the perspectives of the other on the question of sense? Finally, what do these two strands tell us about what Nancy expects of 'art' and what would happen to his ontology of sense without the different appeals he makes to it?
"A Past Which Has Never Been Present": Bergsonian Dimensions in Merleau-Ponty's Theory of the Prepersonal
Authors: Al-Saji Alia
Published: February 2008

Merleau-Ponty's reference to "a past which has never been present" at the end of "Le sentir" challenges the typical framework of the Phenomenology of Perception, with its primacy of perception and bodily field of presence. In light of this "original past," I propose a re-reading of the prepersonal as ground of perception that precedes the dichotomies of subject-object and activity-passivity. Merleau-Ponty searches in the Phenomenology for language to describe this ground, borrowing from multiple registers (notably Bergson, but also Husserl). This "sensory life" is a coexistence of sensing and sensible—bodily and worldly—rhythms. Perception is, then, not a natural given, but a temporal process of synchronization between rhythms. By drawing on Bergson, this can be described as a process in which virtual life is actualized into perceiving subject and object perceived. Significantly, this process involves non-coincidence or delay whereby sensory life is always already past for perception.
The Question of the Living Body in Heidegger's Analytic of Dasein
Authors: Ciocan Cristian
Published: February 2008

The purpose of this article is to analyze the significance of the absence of the problem of living body in Heidegger's analytic of Dasein. In order to evaluate the occurrences of the problem of the body in Being and Time, I also refer to the context of some of Heidegger's later work where there is to be found a sketch of an ontological investigation of the living body. I analyze then in detail the scarce occurrences of body in the fundamental ontology, showing finally that the lack of a proper phenomenological examination of living body generates a series of conceptual difficulties for the problem of Dasein's death, precisely when the issue of dead body is at stake.
The Self as Resolution: Heidegger, Derrida and the Intimacy of the Question of the Meaning of Being
Authors: Russon John
Published: February 2008

Because Dasein, as conceived by Heidegger, is inherently temporal, the "who" of Dasein can never be defined simply in terms of a (self-)present identity but must have the character of what Derrida calls "différance." Dasein 's authenticity, then, must be an embracing of this, its character as différance. This means that the "self" is "neither a substance nor a subject" but a resolution. The anticipatory resoluteness of authenticity, however, is a unique kind of resolve: it is the resolve to be open to transformation. For that reason, Dasein's proper self-appropriation—authenticity—is found precisely in its inherent inappropriability. Because Dasein is always being-in-the-world, the openness of its own "who" is equally an openness of being's "what." Dasein 's authenticity is nothing other than the enactment of the question of the meaning of being.
Science, Scholarship and the Domestication of Religion: On Dennett's Breaking the Spell
Authors: Wiebe Donald
Published: February 2008

In Breaking the Spell Dennett sets out to defend society from religion and to promote a scientific study of religion as one natural phenomenon among many. He maintains that undermining the taboo against submitting religion to scientific scrutiny is essential to breaking the spell of religion itself and eliminating its essentially toxic effects on society. Although of value for the support the book provides for establishing a genuinely scientific study of religion, it is disappointing in its crude (and therefore essentially ineffective) polemic against religion and its ill considered and inconsistent policy statements regarding religion's place in society.