bluuebunny/crossref_metadata_2025 huggingface dataset:
THE DENSITY MATRIX RENORMALIZATION GROUP AND THE NUCLEAR SHELL MODEL
Authors: PITTEL S. , THAKUR B. , SANDULESCU N.
Published: February 2009

We summarize recent efforts to develop an angular-momentum-conserving variant of the Density Matrix Renormalization Group method into a practical truncation strategy for large-scale shell model calculations of atomic nuclei. Following a brief description of the key elements of the method, we report the results of test calculations for 48 Cr and 56 Ni . In both cases we consider nucleons limited to the 2p-1f shell and interacting via the KB3 interaction. Both calculations produce a high level of agreement with the exact shell-model results. Furthermore, and most importantly, the fraction of the complete space required to achieve this high level of agreement goes down rapidly as the size of the full space grows.
TRIAXIAL REFLECTION ASYMMETRIC SHELL MODEL
Authors: CHEN Y. S. , GAO Z. C.
Published: February 2009

The spontaneously broken reflection and axial symmetries in the nuclear mean field and their necessary restorations in the laboratory frame are described in a natural way in the triaxial Reflection Asymmetric Shell Model. This recently developed theoretical model has been applied to explore the possibility that some superheavy nuclei may have an exotic shape, tetrahedral-like. The ground state band and the partner low-lying negative parity bands are calculated for the Cf isotopes and the results are in a good agreement with the available experimental data. The tetrahedral symmetry, realized at the first order with the nonaxial octupole Y 32 deformation, plays an important role for understanding the low-lying band structures in transfermium and superheavy nuclei, but it is significantly obscured by the competing quadrupole deformation as well as the axial octupole component. The calculated reduced E3 transition probabilities between the low lying 2–-band states and the ground band states show a large enhancement of the nonaxial octupole collectivity.
SELF-CONSISTENT DESCRIPTION OF EXOTIC STRUCTURE AND DECAY NEAR THE N = Z LINE
Authors: PETROVICI ALEXANDRINA
Published: February 2009

We focus on exotic structure and dynamics of N ≃ Z nuclei in the A ~ 80 mass region described within the complex Excited Vampir variational approach. We report on the effect of isospin-symmetry breaking on the superallowed Fermi β decay of the ground state of 82 Nb to 82 Zr . Results on the analog as well as non-analog β decay branches are self-consistently obtained. The 82 Nb →82 Zr β decay to the first two excited 0+ states with significant strength is predicted to coexist with the superallowed decay. The structure and electromagnetic properties of the low- and high-spin isobaric analog states in 82 Nb and 82 Zr are presented and compared with the available experimental data. The influence of shape coexistence and mixing on the Gamow–Teller strength distributions for the β+ decay of the ground state as well as the lowest-excited states in 72 Kr to the 1+ states in the beta window in 72 Br are self-consistently described using a rather large model space and realistic effective interactions. Predictions concerning the β decay half-life of the first excited 0+ state of 72 Kr relevant for the rp-process are presented.
NUCLEON PAIR APPROXIMATION OF THE SHELL MODEL: A BRIEF REVIEW
Authors: ZHAO Y. M. , XU Z. Y. , LEI Y. , JIA L. Y.
Published: February 2009

We present a brief introduction of the nucleon pair approximation (NPA) of the shell model in this paper. We review our recent calculated results which include level spectra and electromagnetic properties of low-lying states, by applying the NPA to even-even nuclei and to odd-A nuclei. We also apply this method to a few schematic systems such as single-j shell, to investigate the validity of SD-pair truncation of the shell model.
LOW-LYING EXCITATION MODES IN DEFORMED NEUTRON-RICH NUCLEI
Authors: YOSHIDA KENICHI
Published: February 2009

Low-frequency modes of excitation in deformed neutron-rich nuclei are studied by the use of the deformed quasiparticle-random-phase approximation (QRPA) based on the coordinate-space Hartree–Fock–Bogoliubov formalism. We investigate the microscopic structure of the low-lying Kπ = 0+ modes in neutron-rich Mg , Cr and Fe isotopes. It is found that the spatially extended structure of neutron quasiparticle wave functions around the Fermi level brings about a striking enhancement of the transition strengths. It is also found that the fluctuation of the pairing field plays an important role in generating coherence among two-quasiparticle excitations of neutron. Recent progress towards the self-consistent deformed QRPA calculation using the Skyrme density functional is also presented.
RANDOM MATRIX THEORY AND ITS APPLICATION TO THE DECAY OUT OF A SUPERDEFORMED BAND
Authors: GU JIANZHONG
Published: February 2009

Originally, random matrix theory (RMT) was designed by Wigner to deal with the statistics of eigenvalues and eigenfunctions of complex many-body quantum systems in 1950s. During the last two decades, the RMT underwent an unexpected and rapid development: The RMT has been successfully applied to an ever increasing variety of physical problems, and it has become an important tool to attack many-body problems. In this contribution I briefly outline the development of the RMT and introduce its basics. Its application to the decay out of a Superdeformed band and a comparison of the approach used in Ref. 34 with that proposed by Vigezzi et al are presented. Current theoretical activities on the decay out problem are reviewed, and the influence of the degree of chaoticity of the normally deformed states on the decay out intensity is examined systematically.
PROTON-NEUTRON INTERACTING BOSON-FERMION-FERMION MODEL AND THE EXCHANGE INTERACTIONS
Authors: BRANT S. , YOSHIDA N. , ZUFFI L.
Published: February 2009

The exchange interactions proper to the proton-neutron version of the interacting boson-fermion-fermion model are derived from the proton-neutron quadrupole-quadrupole interaction. The influence of the exchange interactions on the F-spin content of wave functions is analysed for a typical odd-odd nucleus.
MEAN-FIELD PLUS VARIOUS TYPES OF PAIRING INTERACTIONS AND AN EXACT BOSON MAPPING OF THE REDUCED BCS PAIRING INTERACTION
Authors: PAN FENG , XIE MING-XIA , CHEN HONG , BA WEI , YUAN QUAN , DRAAYER JERRY. P.
Published: February 2009

Exact solutions of Nilsson mean-field plus various type of pairing interactions are briefly reviewed. Some even-odd mass differences and moment of inertia of low-lying states for rare earth and actinide nuclei calculated in nearest-orbit pairing and extended pairing models and comparison with the corresponding experimental data are shown. An exact boson mapping of the reduced BCS pairing Hamiltonian is reported. In the mapping, fermion pair operators are mapped exactly to the corresponding bosons. The image of the mapping results in a Bose-Hubbard model with level dependent hopping.
BASIC PRERADICALS AND MAIN INJECTIVE MODULES
Authors: RAGGI FRANCISCO , RÍOS JOSÉ , RINCÓN HUGO , FERNÁNDEZ-ALONSO ROGELIO
Published: February 2009

We consider those injective modules that determine every left exact preradical and we call them main injective modules. We construct a main injective module for every ring and we prove some of its properties. In particular we give a characterization, in terms of main injective modules, of rings with a dimension defined by a filtration in the lattice of left exact preradicals. We define also the concept of basic preradical and prove some of its properties. In particular we prove that the class of all basic preradicals is a set, giving a bijective correspondence with the set of all left exact preradicals.
THE CONJECTURE OF NOWICKI ON WEITZENBÖCK DERIVATIONS OF POLYNOMIAL ALGEBRAS
Authors: DRENSKY VESSELIN , MAKAR-LIMANOV LEONID
Published: February 2009

The Weitzenböck theorem states that if Δ is a linear locally nilpotent derivation of the polynomial algebra K[Z] = K[z1,…,zm] over a field K of characteristic 0, then the algebra of constants of Δ is finitely generated. If m = 2n and the Jordan normal form of Δ consists of 2 × 2 Jordan cells only, we may assume that K[Z] = K[X,Y] and Δ(yi) = xi, Δ(xi) = 0, i = 1,…,n. Nowicki conjectured that the algebra of constants K[X,Y]Δ is generated by x1,…,xn and xiyj – xjyi, 1 ≤ i < j ≤ n. Recently this conjecture was confirmed in the Ph.D. thesis of Khoury with a very computational proof, and also by Derksen whose proof is based on classical results of invariant theory. In this paper we give an elementary proof of the conjecture of Nowicki which does not use any invariant theory. Then we find a very simple system of defining relations of the algebra K[X,Y]Δ which corresponds to the reduced Gröbner basis of the related ideal with respect to a suitable admissible order, and present an explicit basis of K[X,Y]Δ as a vector space.
A NEW CHARACTERIZATION OF U4(7) BY ITS NONCOMMUTING GRAPH
Authors: ZHANG LIANGCAI , SHI WUJIE
Published: February 2009

Let G be a finite nonabelian group and associate a disoriented noncommuting graph ∇(G) with G as follows: the vertex set of ∇(G) is G\Z(G) with two vertices x and y joined by an edge whenever the commutator of x and y is not the identity. In 1987, J. G. Thompson gave the following conjecture.

Thompson's Conjecture If G is a finite group with Z(G) = 1 and M is a nonabelian simple group satisfying N(G) = N(M), then G ≅ M, where N(G) denotes the set of the sizes of the conjugacy classes of G.

In 2006, A. Abdollahi, S. Akbari and H. R. Maimani put forward a conjecture in [1] as follows.

AAM's Conjecture Let M be a finite nonabelian simple group and G a group such that ∇(G)≅ ∇ (M). Then G ≅ M.

Even though both of the two conjectures are known to be true for all finite simple groups with nonconnected prime graphs, it is still unknown for almost all simple groups with connected prime graphs. In the present paper, we prove that the second conjecture is true for the projective special unitary simple group U4(7).
ANTISYMMETRIC ELEMENTS IN GROUP RINGS II
Authors: CRISTO OSNEL BROCHE , JESPERS ERIC , MILIES CESAR POLCINO , MARÍN MANUEL RUIZ
Published: February 2009

Let R be a commutative ring, G a group and RG its group ring. Let φ : RG → RG denote the R-linear extension of an involution φ defined on G. An element x in RG is said to be φ-antisymmetric if φ (x) = -x. A characterization is given of when the φ-antisymmetric elements of RG commute. This is a completion of earlier work.
Working in Six Research Areas: A Multi-Field Sociological Career
Authors: Gans Herbert J.
Published: February 2009

I have written a strictly autobiographical essay about the half dozen areas or fields in which I have done sociological research during my career. One reason for writing the essay is to encourage students to become what I call a “multi,” there being too few in sociology, as in other disciplines in which most researchers do their work in one field. I hope the essay demonstrates that working in many fields can make for a satisfying and productive career. Research across areas also encourages comparative work, and if enough young people become multi-field researchers, sociologists might then develop more interdisciplinary skills, which is even now desirable and may one day be necessary for all the social sciences. My essay also describes how and why I became interested in my six fields and how I moved between them during my career. The rest of the paper describes my major studies and other activities in my fields as well as the institutional and other contexts that I believe have affected my work.
Adenosine receptors and second messenger signaling pathways in rat cardiac fibroblasts
Authors: Epperson Sara A. , Brunton Laurence L. , Ramirez-Sanchez Israel , Villarreal Francisco
Published: February 2009

The ability of adenosine (ADO) to inhibit proliferation and protein synthesis (in particular, collagen synthesis) in cardiac fibroblasts (CF) may ameliorate adverse cardiac remodeling and fibrosis seen in heart failure patients. However, little is known about the signaling pathways that ADO may modulate in CF to alter cell phenotype. Accordingly, this study was designed to identify ADO receptors (AR) and the signaling pathways linked to them in primary cultures of adult rat CF. Quantitative RT-PCR data indicate that the mRNAs for all four known ARs (A1R, A2aR, A2bR, and A3R) are present in rat CF, with a greater prevalence of A2receptor subtypes. No coupling of AR to the Gq-phospholipase C signaling pathway or to mobilization of calcium is measurable. Studies using subtype specific agents imply that the A2aR and A2bR couple to Gs-adenylyl cyclase and A1R couple weakly to Gi-adenylyl cyclase. 2-Chloroadenosine, 5'- N-ethylcarboxamidoadensoine, and other agents that elevate cellular cAMP stimulate extracellular signal-regulated kinase 1/2 activity in a pertussis toxin-insensitive manner. We conclude that a combination of cAMP-dependent signals generated via A2aand A2breceptors likely mediate ADO signaling in adult rat CF.
Characterization and pharmacological evaluation of febrile response on zymosan-induced arthritis in rats
Authors: Kanashiro Alexandre , Pessini Andréa C. , Machado Renes R. , Malvar David do C. , Aguiar Fernando A. , Soares Denis Melo , do Vale Mariana L. , de Souza Glória E. Petto
Published: February 2009

The present study investigated the febrile response in zymosan-induced arthritis, as well as the increase in PGE2concentration in the cerebrospinal fluid (CSF), along with the effects of antipyretic drugs on these responses in rats. Zymosan intra-articularly injected at the dose of 0.5 mg did not affect the body core temperature (Tc) compared with saline (control), whereas at doses of 1 and 2 mg, zymosan promoted a flattened increase in Tc and declined thereafter. The dose of 4 mg of zymosan was selected for further experiments because it elicited a marked and long-lasting Tc elevation starting at 3 1/2 h, peaking at 5 1/2 h, and remaining until 10 h. This temperature increase was preceded by a decrease in the tail skin temperature, as well as hyperalgesia and edema in the knee joint. No febrile response was observed in the following days. In addition, zymosan-induced fever was not modified by the sciatic nerve excision. Zymosan increased PGE2concentration in the CSF but not in the plasma. Oral pretreatment with ibuprofen (5–20 mg/kg), celecoxib (1–10 mg/kg), dipyrone (60–240 mg/kg), and paracetamol (100–200 mg/kg) or subcutaneous injection of dexamethasone (0.25–1.0 mg/kg) dose-dependently reduced or prevented the fever during the zymosan-induced arthritis. Celecoxib (5 mg/kg), paracetamol (150 mg/kg), and dipyrone (120 mg/kg) decreased CSF PGE2concentration and fever during zymosan-induced arthritis, suggesting the involvement of PGE2in this response.
Activation of opioid μ-receptors in medullary raphe depresses sighs
Authors: Zhang Zhenxiong , Xu Fadi , Zhang Cancan , Liang Xiaomin
Published: February 2009

Sighs, a well-known phenomenon in mammals, are substantially augmented by hypoxia and hypercapnia. Because (d-Ala2,N-Me-Phe4,Gly-ol)-enkephalin (DAMGO), a μ-receptor agonist, injected intravenously and locally in the caudal medullary raphe region (cMRR) decreased the ventilatory response to hypoxia and hypercapnia, we hypothesized that these treatments could inhibit sigh responses to these chemical stimuli. The number and amplitude of sighs were recorded during three levels of isocapnic hypoxia (15%, 10%, and 5% O2for 1.5 min) or hypercapnia (3%, 7%, and 10% CO2for 4 min) to test the dependence of sigh responses on the intensity of chemical drive in anesthetized and spontaneously breathing rats. The role of μ-receptors in modulating sigh responses to 10% O2or 7% CO2was subsequently evaluated by comparing the sighs before and after 1) intravenous administration of DAMGO (100 μg/kg), 2) microinjection of DAMGO (35 ng/100 nl) into the cMRR, and 3) intravenous administration of DAMGO after microinjection of d-Phe-Cys-Tyr-d-Trp-Arg-Thr-Pen-Thr-NH2(CTAP, 100 ng/100 nl), a μ-receptor antagonist, into the cMRR. Hypoxia and hypercapnia increased the number, but not amplitude, of sighs in a concentration-dependent manner, and the responses to hypoxia were significantly greater than those to hypercapnia. Systemic and local injection of DAMGO into the cMRR predominantly decreased the number of sighs, while microinjection into the rostral and middle MRR had no or limited effects. Microinjecting CTAP into the cMRR significantly diminished the systemic DAMGO-induced reduction of the number of sighs in response to hypoxia, but not to hypercapnia. Thus we conclude that hypoxia and hypercapnia elevate the number of sighs in a concentration-dependent manner in anesthetized rats, and this response is significantly depressed by activating systemic μ-receptors, especially those within the cMRR.
Augmented uterine artery blood flow and oxygen delivery protect Andeans from altitude-associated reductions in fetal growth
Authors: Julian Colleen Glyde , Wilson Megan J. , Lopez Miriam , Yamashiro Henry , Tellez Wilma , Rodriguez Armando , Bigham Abigail W. , Shriver Mark D. , Rodriguez Carmelo , Vargas Enrique , Moore Lorna G.
Published: February 2009

The effect of high altitude on reducing birth weight is markedly less in populations of high- (e.g., Andeans) relative to low-altitude origin (e.g., Europeans). Uterine artery (UA) blood flow is greater during pregnancy in Andeans than Europeans at high altitude; however, it is not clear whether such blood flow differences play a causal role in ancestry-associated variations in fetal growth. We tested the hypothesis that greater UA blood flow contributes to the protection of fetal growth afforded by Andean ancestry by comparing UA blood flow and fetal growth throughout pregnancy in 137 Andean or European residents of low (400 m; European n = 28, Andean n = 23) or high (3,100–4,100 m; European n = 51, Andean n = 35) altitude in Bolivia. Blood flow and fetal biometry were assessed by Doppler ultrasound, and maternal ancestry was confirmed, using a panel of 100 ancestry-informative genetic markers (AIMs). At low altitude, there were no ancestry-related differences in the pregnancy-associated rise in UA blood flow, fetal biometry, or birth weight. At high altitude, Andean infants weighed 253 g more than European infants after controlling for gestational age and other known influences. UA blood flow and O2delivery were twofold greater at 20 wk in Andean than European women at high altitude, and were paralleled by greater fetal size. Moreover, variation in the proportion of Indigenous American ancestry among individual women was positively associated with UA diameter, blood flow, O2delivery, and fetal head circumference. We concluded that greater UA blood flow protects against hypoxia-associated reductions in fetal growth, consistent with the hypothesis that genetic factors enabled Andeans to achieve a greater pregnancy-associated rise in UA blood flow and O2delivery than European women at high altitude.
Ionic currents in hair cells dissociated from frog semicircular canals after preconditioning under microgravity conditions
Authors: Martini Marta , Canella Rita , Leparulo Alessandro , Prigioni Ivo , Fesce Riccardo , Rossi Maria Lisa
Published: February 2009

The effects of microgravity on the biophysical properties of frog labyrinthine hair cells have been examined by analyzing calcium and potassium currents in isolated cells by the patch-clamp technique. The entire, anesthetized frog was exposed to vector-free gravity in a random positioning machine (RPM) and the functional modification induced on single hair cells, dissected from the crista ampullaris, were subsequently studied in vitro. The major targets of microgravity exposure were the calcium/potassium current system and the kinetic mechanism of the fast transient potassium current, IA. The amplitude of ICawas significantly reduced in microgravity-conditioned cells. The delayed current, IKD(a complex of IKVand IKCa), was drastically reduced, mostly in its IKCacomponent. Microgravity also affected IKDkinetics by shifting the steady-state inactivation curve toward negative potentials and increasing the sensitivity of inactivation removal to voltage. As concerns the IA, the I- V and steady-state inactivation curves were indistinguishable under normogravity or microgravity conditions; conversely, IAdecay systematically displayed a two-exponential time course and longer time constants in microgravity, thus potentially providing a larger K+charge; furthermore, IAinactivation removal at −70 mV was slowed down. Stimulation in the RPM machine under normogravity conditions resulted in minor effects on IKDand, occasionally, incomplete IAinactivation at −40 mV. Reduced calcium influx and increased K+repolarizing charge, to variable extents depending on the history of membrane potential, constitute a likely cause for the failure in the afferent mEPSP discharge at the cytoneural junction observed in the intact labyrinth after microgravity conditioning.
Function and regulation of TRPP2 at the plasma membrane
Authors: Tsiokas Leonidas
Published: February 2009

The vast majority (∼99%) of all known cases of autosomal dominant polycystic kidney disease (ADPKD) are caused by naturally occurring mutations in two separate, but genetically interacting, loci, pkd1 and pkd2. pkd1 encodes a large multispanning membrane protein (PKD1) of unknown function, while pkd2 encodes a protein (TRPP2, polycystin-2, or PKD2) of the transient receptor potential (TRP) superfamily of ion channels. Biochemical, functional, and genetic studies support a model in which PKD1 physically interacts with TRPP2 to form an ion channel complex that conveys extracellular stimuli to ionic currents. However, the molecular identity of these extracellular stimuli remains elusive. Functional studies in cell culture show that TRPP2 can be activated in response to mechanical cues (fluid shear stress) and/or receptor tyrosine kinase (RTK) and G protein-coupled receptor (GPCR) activation at the cell surface. Recent genetic studies in Chlamydomonas reinhardtii show that CrPKD2 functions in a pathway linking cell-cell adhesion and Ca2+signaling. The mode of activation depends on protein-protein interactions with other channel subunits and auxiliary proteins. Therefore, understanding the mechanisms underlying the molecular makeup of TRPP2-containing complexes is critical in delineating the mechanisms of TRPP2 activation and, most importantly, the mechanisms by which naturally occurring mutations in pkd1 or pkd2 lead not only to ADPKD, but also to other defects reported in model organisms lacking functional TRPP2. This review focuses on the molecular assembly, function, and regulation of TRPP2 as a cell surface cation channel and discusses its potential role in Ca2+signaling and ADPKD pathophysiology.
Augmentation of endogenous intrarenal angiotensin II levels in Val5-ANG II-infused rats
Authors: Shao Weijian , Seth Dale M. , Navar L. Gabriel
Published: February 2009

In angiotensin II (ANG II)-induced hypertension, intrarenal ANG II levels are increased by AT1 receptor-mediated ANG II internalization and endogenous ANG II generation. The objective of the present study was to determine the relative contribution of de novo formation of endogenous ANG II. Male Sprague-Dawley rats were divided into three groups: sham operated ( n = 6), Val5-ANG II infused ( n = 16), and Ile5-ANG II infused ( n = 6). Val5-ANG II and Ile5-ANG II were infused at 80 ng/min via subcutaneous osmotic minipump for 13 days, followed by harvesting of blood and kidney samples. In six Val5-ANG II-infused rats, urine was collected on the day before infusion and on day 12 of infusion. Extracted samples were subjected to HPLC to separate Val5-ANG II from Ile5-ANG II followed by RIA. Systolic blood pressure increased significantly from 121 ± 2 to 206 ± 4 mmHg in the Val5-ANG II-infused rats and from 124 ± 3 to 215 ± 5 mmHg in the Ile5-ANG II-infused rats. In the Val5-ANG II-infused rats, the plasma Ile5-ANG II levels increased 196.2 ± 70.1% compared with sham plasma Ile5-ANG II concentration. Val5-ANG II levels were 150.0 ± 28.2 fmol/ml which accounted for 53.5 ± 10.1% of the total ANG II in plasma. The kidney Ile5-ANG II levels in the Val5-ANG II-infused rats increased 69.9 ± 30.7% compared with sham kidney Ile5-ANG II concentrations. Intrarenal accumulation of Val5-ANG II accounted for 52.5 ± 5.3% of the total kidney ANG II during Val5-ANG II infusion while endogenous Ile5-ANG II accounted for 47.5 ± 8.6%. The urinary Ile5-ANG II excretion rate on day 12 increased 93.2 ± 32.1% compared with preinfusion level indicating increased formation of endogenous ANG II. Thus, the increases in intrarenal ANG II levels during chronic ANG II infusions involve substantial stimulation of endogenous ANG II formation which contributes to overall augmentation of intrarenal ANG II.
Spironolactone ameliorates transplant vasculopathy in renal chronic transplant dysfunction in rats
Authors: Waanders Femke , Rienstra Heleen , Boer Mark Walther , Zandvoort André , Rozing Jan , Navis Gerjan , van Goor Harry , Hillebrands Jan-Luuk
Published: February 2009

Chronic transplant dysfunction (CTD) is the leading cause of long-term renal allograft loss and is characterized by specific histological lesions including transplant vasculopathy, interstitial fibrosis, and focal glomerulosclerosis. Increasing evidence indicates that aldosterone is a direct mediator of renal damage via the mineralocorticoid receptor (MR). The MR antagonist spironolactone is renoprotective in native chronic kidney disease, but its effects on CTD are unknown. We studied the effects of spironolactone treatment on CTD development in the Dark Agouti-to-Wistar-Furth renal allograft transplant model, by treatment with 20 mg/kg spironolactone or vehicle daily by oral gavage from 2 days before transplantation (donors and recipients) throughout the experiment (12 wk, recipients). Dark Agouti-to-Dark Agouti isografts served as negative controls. Spironolactone significantly ameliorated the development of transplant vasculopathy in allografts by reducing the number of affected intrarenal arteries. In addition, spironolactone treatment showed a trend toward reduced proteinuria and focal glomerulosclerosis, and significantly reduced glomerular macrophage influx. However, spironolactone treatment did not affect interstitial fibrosis, interstitial macrophage influx, creatinine clearance, and systolic blood pressure. We conclude that spironolactone selectively ameliorates transplant vasculopathy and glomerular lesions in renal CTD in rats. These results suggest that spironolactone may have renoprotective potential as an adjunct treatment in renal transplantation to ameliorate CTD.
Nitric oxide reduces flow-induced superoxide production via cGMP-dependent protein kinase in thick ascending limbs
Authors: Hong Nancy J. , Garvin Jeffrey L.
Published: February 2009

We have shown that increased luminal flow induces O2− and nitric oxide (NO) production in thick ascending limbs (TALs). However, the interaction of flow-stimulated NO and O2− in TALs is unclear. We hypothesized that NO inhibits flow-induced O2− production in TALs via cGMP-dependent protein kinase (PKG). We measured flow-stimulated O2− production in rat TALs using dihydroethidium in the absence and presence of l-arginine (0.3 mM), the substrate for NO synthase. The addition of l-arginine reduced flow-induced net O2− production from 68 ± 9 to 17 ± 4 AU/s ( P < 0.002). The addition of the NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME; 5 mM) in the presence of l-arginine stimulated production (l-arginine: 15 ± 4 AU/s vs. l-arginine + l-NAME: 63 ± 7 AU/s; P < 0.002). The guanylate cyclase inhibitor LY-83583 (10 μM) also enhanced flow-induced net O2− production in the presence of l-arginine (l-arginine: 7 ± 4 AU/s vs. l-arginine + LY-83583: 53 ± 7 AU/s; P < 0.01). In the presence of LY-83583, l-arginine only reduced flow-induced net O2− by 36% (LY-83583: 80 ± 7 AU/s vs. LY-83583 + l-arginine: 51 ± 3 AU/s; P < 0.006). The cGMP analog dibutyryl (db)-cGMP reduced flow-induced net O2− from 39 ± 9 to 7 ± 3 AU/s ( P < 0.03). The PKG inhibitor KT-5823 (5 μM) partially restored flow-induced net O2− in the presence of l-arginine (l-arginine: 4 ± 4 AU/s vs. l-arginine + KT-5823: 32 ± 9 AU/s; P < 0.03) and db-cGMP (db-cGMP: 9 ± 7 AU/s vs. db-cGMP + KT-5823: 54 ± 5 AU/s; P < 0.01). Phosphodiesterase II inhibition had no effect on arginine-inhibited O2− production. We conclude that 1) NO reduces flow-stimulated O2− production, 2) this occurs primarily via the cGMP/PKG pathway, and 3) O2− scavenging by NO plays a minor role.
Strain differences in urinary factors that promote calcium oxalate crystal formation in the kidneys of ethylene glycol-treated rats
Authors: Li Yan , McMartin Kenneth E.
Published: February 2009

Ethylene glycol (EG)-induced hyperoxaluria is the most commonly employed experimental regimen as an animal model of calcium oxalate (CaOx) stone formation. The variant sensitivity to CaOx among different rat strains has not been fully explored, although the Wistar rat is known to accumulate more CaOx in kidney tissue after low-dose EG exposure than in the Fischer 344 (F344) rats. Supersaturation of CaOx in tubular fluid contributes to the amount of CaOx crystal formation in the kidney. We hypothesized that the urinary supersaturation of CaOx in Wistar rats is higher than that of F344 rats, thereby allowing for greater CaOx crystal deposition in the Wistar rat. Age-matched male Wistar and F344 rats were treated with 0.75% EG or drinking water for 8 wk. Twenty-four-hour urine was collected at 0, 2, 4, 6, and 8 wk for analysis of key electrolytes to calculate the CaOx supersaturation. Plasma oxalate level was also measured. Our data confirmed the different sensitivity to renal toxicity from EG between the two rat strains (Wistar > F344). After EG treatment, the plasma oxalate level and urine oxalate excretion were markedly greater in the Wistar rats than in the F344 rats, while urine calcium was slightly decreased in Wistars. Thus, the CaOx supersaturation in urine of Wistar rats was higher, which led to a greater crystal deposition in kidney in Wistar rats. These studies suggest that during EG treatment, changes in urine electrolytes and in CaOx supersaturation occur to a greater extent in the Wistar rat, in agreement with its greater sensitivity to EG toxicity.
Effect of biventricular pacing on ventilatory and perceptual responses to exercise in patients with stable chronic heart failure
Authors: Laveneziana Pierantonio , O'Donnell Denis E. , Ofir Dror , Agostoni PierGiuseppe , Padeletti Luigi , Ricciardi Giuseppe , Palange Paolo , Duranti Roberto , Scano Giorgio
Published: February 2009

Despite the growing evidence supporting the use of biventricular cardiac resynchronization therapy (CRT) in patients with chronic heart failure (CHF), the mechanisms whereby acute hemodynamic improvements lead to improved exertional dyspnea are not precisely known. We hypothesized that improved cardiac function and ventilation-perfusion relations following CRT would reduce ventilatory demand, thereby improving dynamic operating lung volumes and enhancing tidal volume expansion during exercise. This, in turn, would be expected to reduce perceived exertional dyspnea and contribute to improved exercise performance. In a randomized, double-blind, crossover study, we compared cardiovascular, metabolic, ventilatory responses (breathing pattern, operating lung volumes, pulmonary gas exchange) and exertional symptoms in seven stable CHF patients who undertook incremental cardiopulmonary cycle exercise test with CRT switched to the “on” (CRTon) or “off” (CRToff) modality. Following CRTon, peak oxygen uptake was significantly increased by 15%, and dyspnea ratings were lower for a given work rate (at work rate of 40 W, dyspnea = 1 ± 0.4 vs. 2.5 ± 0.9 Borg units, P < 0.05) and ventilation (at ventilation of 31 l/min, dyspnea = 2 ± 0.7 vs. 3.3 ± 1.1 Borg units, P < 0.05). CRTon was associated with improvements in ventilatory threshold, oxygen pulse, and oxygen uptake/work rate relationships (10.2 ± 1 vs. 7.9 ± 1.3 ml·min−1·W−1, P < 0.05). CRTon reduced the ventilatory requirement during exercise as well as the steepness of ventilation-CO2 production slope (35 ± 4 vs. 45 ± 7, P < 0.05). Changes in end-expiratory lung volume during exercise were less with CRTon than with CRToff (0.12 vs. 0.37 liter, P < 0.05), and breathing pattern was correspondingly slower and deeper. Biventricular pacing improved all noninvasive indexes of cardiac function and oxygen delivery during exercise. The decreased ventilatory demand, improved dynamic operating lung volumes, and the increased ability to expand tidal volume during exercise are potential factors in the reduction of exertional dyspnea.
Ca2+-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca2+Pump in Hippocampal Neurons
Authors: Ferragamo Michael J. , Reinardy Jessica L. , Thayer Stanley A.
Published: February 2009

The plasma membrane Ca2+ATPase (PMCA) plays a major role in restoring Ca2+to basal levels following transient elevation by neuronal activity. Here we examined the effects of various stimuli that increase [Ca2+]ion PMCA-mediated Ca2+clearance from hippocampal neurons. We used indo-1-based microfluorimetry in the presence of cyclopiazonic acid to study the rate of PMCA-mediated recovery of Ca2+elevated by a brief train of action potentials. [Ca2+]irecovery was described by an exponential decay and the time constant provided an index of PMCA-mediated Ca2+clearance. PMCA function was assessed before and for ≥60 min following a 10-min priming stimulus of either 100 μM N-methyl-d-aspartate (NMDA), 0.1 mM Mg2+(reduced extracellular Mg2+induces intense excitatory synaptic activity), 30 mM K+, or control buffer. Recovery kinetics slowed progressively following priming with NMDA or 0.1 mM Mg2+; in contrast, Ca2+clearance initially accelerated and then slowly returned to initial rates following priming with 30 mM K+-induced depolarization. Treatment with 10 μM calpeptin, an inhibitor of the Ca2+activated protease calpain, prevented the slowing of kinetics observed following treatment with NMDA but had no affect on the recovery kinetics of control cells. Calpeptin also blocked the rapid acceleration of Ca2+clearance following depolarization. In calpeptin-treated cells, 0.1 mM Mg2+induced a graded acceleration of Ca2+clearance. Thus in spite of producing comparable increases in [Ca2+]i, activation of NMDA receptors, depolarization-induced activation of voltage-gated Ca2+channels and excitatory synaptic activity each uniquely affected Ca2+clearance kinetics mediated by the PMCA.
Measuring Correlations and Interactions Among Four Simultaneously Recorded Brain Regions During Learning
Authors: Paz Rony , Bauer Elizabeth P. , Paré Denis
Published: February 2009

Brain function depends on coordinated interactions in spatially distributed neuronal populations. Thanks to recent technological advances, it is now possible to monitor the activity of large groups of neurons. Although significant progress has been made in analyzing neuronal interactions across large samples of simultaneously recorded cells, most of the available approaches do not allow direct visualization of multidimensional correlations in the time domain. This study describes a novel analysis technique, termed four-dimensional spike-triggered joint histogram (4-d STJH) that permits the study of co-modulations of unit activity across four simultaneously recorded brain regions while preserving the time domain. To illustrate how this technique works, we recorded simultaneously from basolateral amygdala (BLA) and medial prefrontal (mPFC), as well as perirhinal and entorhinal neurons in animals learning an appetitive trace-conditioning task. Using the 4d-STJH, we show that coincident activity in the BLA and mPFC modulates the interactions between perirhinal and entorhinal neurons in a manner that cannot be explained by a linear combination of the individual BLA and mPFC-related modulations. We conclude with a discussion of the strengths and limitations of 4-d STJH and offer recommendations regarding optimal conditions for its use.
Dopamine Inhibits N-Type Channels in Visceral Afferents to Reduce Synaptic Transmitter Release Under Normoxic and Chronic Intermittent Hypoxic Conditions
Authors: Kline David D. , Hendricks Gabriel , Hermann Gerlinda , Rogers Richard C. , Kunze Diana L.
Published: February 2009

Glutamatergic synaptic currents elicited in second-order neurons in the nucleus of the solitary tract (nTS) by activation of chemosensory and other visceral afferent fibers are severely reduced following 10 days of chronic intermittent hypoxia (CIH). The mechanism by which this occurs is unknown. A strong candidate for producing the inhibition is dopamine, which is also released from the presynaptic terminals and which we have shown exerts a tonic presynaptic inhibition on glutamate release. We postulated that tonic activation of the D2 receptors inhibits presynaptic calcium currents to reduce transmitter release and that in CIH this occurs in conjunction with an increase in the dopamine inhibitory response due to the increase in presynaptic D2 receptors or an increase in dopamine release further suppressing the evoked excitatory postsynaptic current (eEPSC). Thus we predicted that blockade of the D2 receptors would return the EPSC to values of animals maintained under normoxic conditions. We found that dopamine and quinpirole, the selective D2-like agonist, inhibit calcium currents via the D2 receptors by acting on the N-type calcium channel in presynaptic neurons and their nTS central terminals. However, in brain slice studies from CIH animals, although the D2 antagonist sulpiride increased the CIH-reduced amplitude of synaptic currents, EPSCs were not restored to normal levels. This indicates that while the dopamine inhibitory effect remains intact in CIH, most of the reduction in the eEPSC amplitude occurs via alternative mechanisms.
A Painful Cutaneous Laser Stimulus Evokes Responses From Single Neurons in the Human Thalamic Principal Somatic Sensory Nucleus Ventral Caudal (Vc)
Authors: Kobayashi K. , Winberry J. , Liu C. C. , Treede R. D. , Lenz F. A.
Published: February 2009

Cutaneous application of painful radiant heat laser pulses evokes potentials (laser-evoked potentials) that can be recorded from scalp or intracranial electrodes. We have now tested the hypothesis that the response of thalamic neurons to a cutaneous laser stimulus occurs at latencies predicted by the conduction delay between the periphery and the thalamus. We have carried out recordings from human thalamic neurons in the principal sensory nucleus (ventral caudal) in patients undergoing awake surgery for the treatment of tremor. The results demonstrate that many neurons respond to the laser with early and/or late latency peaks of activity, consistent with conduction of the response to the laser stimulus through pathways from Aδ and C fibers to the thalamus. These peaks were of short duration, perhaps due to the somatotopic- and modality-specific arrangements of afferent pathways to the thalamus. The responses of these thalamic neurons to the laser stimulus sometimes included low-threshold spike (LTS) bursts of action potentials, consistent with previous studies of different painful stimuli. A prior study has demonstrated that spike trains characterized by common LTS bursts such as the intermediate (I) category spontaneously change their category more commonly than do those without LTS bursts (NG: nongrouped category) during changes in the cognitive task. Spike trains of laser-responsive neurons were more common in the I category, whereas those of laser nonresponsive neurons were more common in the NG category. Therefore neuronal spike trains in the I category may mediate shifts in endogenous or cognitive pain-related behavior.
Image of Lp(ℝn) under the Hermite Semigroup
Authors: Radha R. , Naidu D. Venku
Published: February 2009

It is shown that the Hermite (polynomial) semigroup {e−tℍ : t > 0} maps Lp(ℝn, ρ) into the space of holomorphic functions in for each ϵ > 0, where ρ is the Gaussian measure, is a scaled version of Gaussian measure with r = p if 1 < p < 2 and r = p′ if 2 < p < ∞ with 1/p + 1/p′ = 1. Conversely if F is a holomorphic function which is in a “slightly” smaller space, namely , then it is shown that there is a function f ∈ Lp(ℝn, ρ) such that e−tℍf = F. However, a single necessary and sufficient condition is obtained for the image of L2(ℝn, ρp/2) under e−tℍ, 1 < p < ∞. Further it is shown that if F is a holomorphic function such that or , then there exists a function f ∈ Lp(ℝn, ρ) such that e−tℍf = F, where and 1 < p < ∞.
Dynamic Behaviors of a General Discrete Nonautonomous System of Plankton Allelopathy with Delays
Authors: Chen Yaoping , Chen Fengde , Li Zhong
Published: February 2009

We study the dynamic behaviors
of a general discrete nonautonomous system of plankton
allelopathy with delays. We first show that under some suitable
assumption, the system is permanent. Next, by constructing a
suitable Lyapunov functional, we obtain a set of sufficient
conditions which guarantee the global attractivity of the two
species. After that, by constructing an extinction‐type Lyapunov
functional, we show that under some suitable assumptions, one
species will be driven to extinction. Finally, two examples
together with their numerical simulations show the feasibility of
the main results.
Design of Sectoral Antennas Using a Metallic EBG Structure and Multiple Sources Feeding for Base Station Applications
Authors: Hajj M. , Rodes E. , Serhal D. , Monédière T. , Jecko B.
Published: February 2009

This work aims to study and design base station antennas with metallic electromagnetic band gap (EBG) materials able to create a sectoral radiation pattern presenting at least a 60∘ beamwidth. The use of metallic structures offers a new approach to industrial partners seeking to reduce costs and facilitate design procedures. A new method allowing the improvement of both the directivity and the bandwidth by using a printed antenna array is studied.
Differences in Transcriptional Activation by the Two Allelic (L162V Polymorphic) Variants of PPARα after Omega‐3 Fatty Acids Treatment
Authors: Rudkowska Iwona , Verreault Mélanie , Barbier Olivier , Vohl Marie-Claude
Published: February 2009

Omega‐3 fatty acids (FAs) have the potential to regulate gene
expression via the peroxisome proliferator‐activated receptor α (PPARα);
therefore, genetic variations in this gene may
impact its
transcriptional activity on target genes. It is hypothesized that
the transcriptional activity by wild‐type L162‐PPARα is enhanced
to a greater extent than the mutated variant (V162‐PPARα) in the
presence of eicosapentaenoic acid (EPA), docosahexaenoic acid
(DHA) or a mixture of EPA:DHA. To examine the functional
difference of the two allelic variants on receptor activity,
transient co‐transfections were performed in human hepatoma HepG2
cells activated with EPA, DHA and EPA:DHA mixtures. Results
indicate that the addition of EPA or DHA demonstrate potential to
increase the transcriptional activity by PPARα with respect to
basal level in both variants. Yet, the EPA:DHA mixtures enhanced
the transcriptional activity to a greater extent than individual
FAs indicating possible additive effects of EPA and DHA.
Additionally, the V162 allelic form of PPARα demonstrated
consistently lower transcriptional activation when incubated with
EPA, DHA or EPA:DHA mixtures than, the wild‐type variant. In
conclusion, both allelic variants of the PPARα L162V are activated
by omega‐3 FAs; however, the V162 allelic form displays a lower
transcriptional activity than the wild‐type variant.
Penile Rehabilitation Therapy with PDE-V Inhibitors Following Radical Prostatectomy: Proceed with Caution
Authors: Brewer M. Eric , Kim Edward D.
Published: February 2009

Penile rehabilitation therapy following radical prostatectomy is a much debated topic. Erectile dysfunction is still a significant contributor to postoperative morbidity following radical prostatectomy, despite meticulous nerve-sparing technique. Secondary smooth muscle changes in the penis have been identified as the underlying causes of penile atrophy, veno-occlusive dysfunction, and fibrosis. Initial observations that intracavernous injection therapies used on a regular basis postoperatively resulted in improvements in the return of spontaneous erectile function led to the development of penile rehabilitation protocols. Chronic dosing of PDE-V inhibitors is now commonly used by urologists after radical prostatectomy. Despite the current enthusiasm of penile rehabilitation therapy, current scientific evidence with clinical trials is still limited.
Picturing Victory The Visual Imaginary of the War of Resistance, 1937–1947
Authors: Mitter Rana
Published: February 2009

The Sino-Japanese War of 1937–1947 has not been sufficiently understood as a narrative in its own right, but rather, as a transitional conflict between Nationalist and Communist rule. The examination of the visual imagery of warfare disseminated through newsprint and books is one way to reinterpret the history of this period. Through a close reading of images printed in a Shanghai newspaper, Zhonghua ribao, during the final days of the battle for the city in 1937, we see how the news was shaped to impose a narrative of order with a positive teleology at a time when China was plunged into chaos with no guarantee of the eventual outcome of the war. The nature of this narrative is explored through examination of images of the body, as well as the positioning of images in the context of the printed page. The conclusion then contrasts these images with a pictorial history of the Sino-Japanese War published during the Civil War, in 1947. It suggests that although this book is able to bring narrative closure to the earlier conflict, its own narrative is imbued with an unease caused by the reality of the new war that had broken out within months of the ending of the war against Japan, and suggests that narrative closure is never truly obtained.
Anticipatory Guidance for Prevention of Childhood Obesity: Design of the MOMS Project
Authors: Groner Judith A. , Skybo Theresa , Murray-Johnson Lisa , Schwirian Patricia , Eneli Ihuoma , Sternstein Amy , Klein Elizabeth , French Gina
Published: February 2009

The prevalence of childhood overweight and obesity in the United States has increased by more than 100% since 1971. Primary care clinicians have a unique opportunity to influence child health during the first year of life via anticipatory guidance (AG). However, little is known about whether AG regarding feeding and meal structure is effective in promoting optimal nutrition and eating behaviors. The purpose of this project, “Making our Mealtimes Special” (MOMS), was to assess 2 distinct methods of pediatric AG during infancy versus a “usual care” condition, with the ultimate goal of prevention of childhood overweight and obesity. The purpose of this article is to describe the ( a) study design and rationale, ( b) implementation plan, ( c ) assessment of outcomes, and ( d) population enrolled. This project will generate important information on the usefulness of nutritional AG during the first year of life in promoting healthy eating behaviors during early childhood.