bluuebunny/crossref_metadata_2025 huggingface dataset:
BOUNDS ON QUARK MASS MATRICES ELEMENTS DUE TO MEASURED PROPERTIES OF THE MIXING MATRIX AND PRESENT VALUES OF THE QUARK MASSES
Authors: CHATURVEDI S. , GUPTA V. , SÁNCHEZ-COLÓN G.
Published: May 2008

We obtain constraints on possible structures of mass matrices in the quark sector by using as experimental restrictions the determined values of the quark masses at the MZ energy scale, the magnitudes of the quark mixing matrix elements V ud , V us , V cd and V cs , and the Jarlskog invariant J(V). Different cases of specific mass matrices are examined in detail. The quality of the fits for the Fritzsch- and Stech-type mass matrices is about the same with χ2/ d.o.f. = 4.23/3 = 1.41 and χ2/ d.o.f. = 9.10/4 = 2.28, respectively. The fit for a simple generalization (one extra parameter) of the Fritzsch type matrices, in the physical basis, is much better with χ2/ d.o.f. = 1.89/4 = 0.47. For comparison we also include the results using the quark masses at the 2 GeV energy scale. The fits obtained at this energy scale are similar to that at MZ energy scale, implying that our results are unaffected by the evolution of the quark masses from 2 to 91 GeV.
STABILITY OF CYLINDRICAL TRANSONIC SHOCKS FOR THE TWO-DIMENSIONAL STEADY COMPRESSIBLE EULER SYSTEM
Authors: LIU LI , YUAN HAIRONG
Published: May 2008

We establish the stability of a class of cylindrical symmetric transonic shocks for two-dimensional complete compressible steady Euler system. This result partly explains the effectiveness of the popular quasi-one-dimensional model of nozzle flows used in aerodynamics. Mathematically, we solve a nonlinear free boundary problem of an elliptic-hyperbolic composite system, with the circular transonic shock front as the free boundary. We accomplish this by finding a (locally) unique fixed point of an appropriately defined boundary profile updating mapping. To define this mapping, we encounter a series of nonclassical boundary value problems in an annulus, which involve a new type of nonlocal elliptic problem, and integral-like solvability conditions to determine the position of the free boundary. This reflects an interesting new feature of boundary value problems of elliptic-hyperbolic composite systems.
AN ALTERNATING EVOLUTION APPROXIMATION TO SYSTEMS OF HYPERBOLIC CONSERVATION LAWS
Authors: LIU HAILIANG
Published: May 2008

In this paper, we present an alternating evolution (AE) approximation [Formula: see text] to systems of hyperbolic conservation laws [Formula: see text] in arbitrary spatial dimension. We prove the convergence of the approximate solutions towards an entropy solution of scalar multi-D conservation laws, and the L1 contraction property for the approximate solution is established as well. It is also shown that such an approximation is extremely accurate in the sense that if initial data is prepared such that u0 = v0 = U0, then no method error is induced as time evolves, and the exact entropy solution is precisely captured. Furthermore, in the approximation system time evolution of one variable is associated with spatial redistribution in another variable. These features render such an approximation ideal to be used for construction of high resolution numerical schemes to solve hyperbolic conservation laws. The usual obstacles caused by jumps crossing computational cell interfaces are not felt when both u and v are sampled alternatively, and reconstructed independently. Herewith we discuss the designing principle for constructing AE schemes, with illustration of two preliminary schemes for systems of conservation laws in one dimension. Both l∞ monotonicity and the TVD (Total Variational Diminishing) property are established for these schemes when applied to the scalar laws.
The Exotic XYZ Charmonium-Like Mesons
Authors: Godfrey Stephen , Olsen Stephen L.
Published: May 2008

Charmonium, the spectroscopy of [Formula: see text] mesons, has recently enjoyed a renaissance with the discovery of several missing states and numerous unexpected charmonium-like resonances. These discoveries were made possible by the extremely large data samples made available by the B factories at SLAC and KEK, as well as CESR. Conventional [Formula: see text] states are well described by quark potential models; however, many of the newly discovered charmonium-like mesons do not seem to fit into the conventional [Formula: see text] spectrum. There is growing evidence that at least some of these new states are exotic, e.g., new forms of hadronic matter such as mesonic molecules, tetraquarks, and/or hybrid mesons. In this review we describe expectations for the properties of conventional charmonium states and the predictions for molecules, tetraquarks, and hybrids and the various processes that produce them. We examine the evidence for the new candidate exotic mesons, possible explanations, and experimental measurements that might reveal the nature of these states.
The COOH terminus of megalin regulates gene expression in opossum kidney proximal tubule cells
Authors: Li Yuanli , Cong Rong , Biemesderfer Daniel
Published: May 2008

We recently reported that megalin is subjected to regulated intramembrane proteolysis (RIP) and includes 1) protein kinase C (PKC)-regulated, metalloprotease-mediated ectodomain shedding producing a membrane-bound megalin COOH-terminal fragment (MCTF) and 2) γ-secretase-mediated cleavage of the MCTF producing a soluble megalin intracellular domain (MICD). Based on studies of RIP of other receptors, the MICD is predicted to target to the nucleus and regulate gene expression. To determine whether RIP of megalin regulates proximal tubule gene expression, we stably expressed the transfected MCTF (tMCTF) or transfected MICD (tMICD) in opossum kidney proximal tubule (OKP) cells and examined the resulting phenotype. Immunoblotting and immunocytochemical analysis of tMCTF cells showed the tMCTF was expressed and constitutively processed by γ-secretase. Analysis of specific protein expression in tMCTF- and tMICD-transfected cells using Western blot showed endogenous megalin and Na+/H+ exchanger 3 (NHE3) protein expression to be dramatically lower than that of control cells. Expression of other proteins including myosin VI, β-adaptin, and the Na-K-ATPase appeared unchanged. Analysis of specific mRNA expression using quantitative real-time PCR showed megalin and NHE3 mRNA levels were significantly lower in tMCTF- and tMICD-transfected cells compared with controls. Inhibition of γ-secretase activity in tMCTF cells resulted in an 8- to 10-fold recovery of megalin mRNA within 4 h. These data show that the COOH-terminal domain of megalin regulates expression of specific proteins in OKP cells and provides the first evidence that RIP of megalin may be part of a signaling pathway linking protein absorption and gene expression in proximal tubule.
mCLCA4 ER processing and secretion requires luminal sorting motifs
Authors: Huan Chunlei , Greene Kai Su , Shui Bo , Spizz Gwendolyn , Sun Haitao , Doran Robert M. , Fisher Patricia J. , Roberson Mark S. , Elble Randolph C. , Kotlikoff Michael I.
Published: May 2008

Ca+-activated Cl− channel (CLCA) proteins are encoded by a family of highly related and clustered genes in mammals that are markedly upregulated in inflammation and have been shown to affect chloride transport. Here we describe the cellular processing and regulatory sequences underlying murine (m) CLCA4 proteins. The 125-kDa mCLCA4 gene product is cleaved to 90- and 40-kDa fragments, and the NH2- and COOH-terminal fragments are secreted, where they are found in cell media and associated with the plasma membrane. The 125-kDa full-length protein is only found in the endoplasmic reticulum (ER), and specific luminal diarginine retention and dileucine forward trafficking signals contained within the CLCA4 sequence regulate export from the ER and proteolytic processing. Mutation of the dileucine luminal sequences resulted in ER trapping of the immaturely glycosylated 125-kDa peptide, indicating that proteolytic cleavage occurs following recognition of the trafficking motifs. Moreover, the mutated dileucine and diarginine signal sequences directed processing of a secreted form of enhanced green fluorescent protein in a manner consistent with the effects on mCLCA4.
Extracellular matrix-specific focal adhesions in vascular smooth muscle produce mechanically active adhesion sites
Authors: Sun Zhe , Martinez-Lemus Luis A. , Hill Michael A. , Meininger Gerald A.
Published: May 2008

Integrin-mediated mechanotransduction in vascular smooth muscle cells (VSMCs) plays an important role in the physiological control of tissue blood flow and vascular resistance. To test whether force applied to specific extracellular matrix (ECM)-integrin interactions could induce myogenic-like mechanical activity at focal adhesion sites, we used atomic force microscopy (AFM) to apply controlled forces to specific ECM adhesion sites on arteriolar VSMCs. The tip of AFM probes were fused with a borosilicate bead (2∼5 μm) coated with fibronectin (FN), collagen type I (CNI), laminin (LN), or vitronectin (VN). ECM-coated beads induced clustering of α5- and β3-integrins and actin filaments at sites of bead-cell contact indicative of focal adhesion formation. Step increases of an upward ( z-axis) pulling force (800∼1,600 pN) applied to the bead-cell contact site for FN-specific focal adhesions induced a myogenic-like, force-generating response from the VSMC, resulting in a counteracting downward pull by the cell. This micromechanical event was blocked by cytochalasin D but was enhanced by jasplakinolide. Function-blocking antibodies to α5β1- and αvβ3-integrins also blocked the micromechanical cell event in a concentration-dependent manner. Similar pulling experiments with CNI, VN, or LN failed to induce myogenic-like micromechanical events. Collectively, these results demonstrate that mechanical force applied to integrin-FN adhesion sites induces an actin-dependent, myogenic-like, micromechanical event. Focal adhesions formed by different ECM proteins exhibit different mechanical characteristics, and FN appears of particular relevance in its ability to strongly attach to VSMCs and to induce myogenic-like, force-generating reactions from sites of focal adhesion in response to externally applied forces.
Cardiac peroxiredoxins undergo complex modifications during cardiac oxidant stress
Authors: Schröder Ewald , Brennan Jonathan P. , Eaton Philip
Published: May 2008

Peroxiredoxins (Prdxs), a family of antioxidant and redox-signaling proteins, are plentiful within the heart; however, their cardiac functions are poorly understood. These studies were designed to characterize the complex changes in Prdxs induced by oxidant stress in rat myocardium. Hydrogen peroxide, a Prdx substrate, was used as the model oxidant pertinent to redox signaling during health and to injury at higher concentrations. Rat hearts were aerobically perfused with a broad concentration range of hydrogen peroxide by the Langendorff method, homogenized, and analyzed by immunoblotting. Heart extracts were also analyzed by size-exclusion chromatography under nondenaturing conditions. Hydrogen peroxide-induced changes in disulfide bond formation, nonreversible oxidation of cysteine (hyperoxidation), and subcellular localization were determined. Hydrogen peroxide induced an array of changes in the myocardium, including formation of disulfide bonds that were intermolecular for Prdx1, Prdx2, and Prdx3 but intramolecular within Prdx5. For Prdx1, Prdx2, and Prdx5, disulfide bond formation can be approximated to an EC50of 10–100, 1–10, and 100–1,000 μM peroxide, respectively. Hydrogen peroxide induced hyperoxidation, not just within monomeric Prdx (by SDS-PAGE), but also within Prdx disulfide dimers, and reflects a flexibility within the dimeric unit. Prdx oxidation was also associated with movement from the cytosolic to the membrane and myofilament-enriched fractions. In summary, Prdxs undergo a complex series of redox-dependent structural changes in the heart in response to oxidant challenge with its substrate hydrogen peroxide.
Increased vasoconstriction predisposes to hyperpnea and postural faint
Authors: Taneja Indu , Medow Marvin S. , Glover June L. , Raghunath Neeraj K. , Stewart Julian M.
Published: May 2008

Our prior studies indicated that postural fainting relates to splanchnic hypervolemia and thoracic hypovolemia during orthostasis. We hypothesized that thoracic hypovolemia causes excessive sympathetic activation, increased respiratory tidal volume, and fainting involving the pulmonary stretch reflex. We studied 18 patients 13–21 yr old, 11 who fainted within 10 min of upright tilt (fainters) and 7 healthy control subjects. We measured continuous blood pressure and heart rate, respiration by inductance plethysmography, end-tidal carbon dioxide (ETCO2) by capnography, and regional blood flows and blood volumes using impedance plethysmography, and we calculated arterial resistance with patients supine and during 70° upright tilt. Splanchnic resistance decreased until faint in fainters (44 ± 8 to 21 ± 2 mmHg·l−1·min−1) but increased in control subjects (47 ± 5 to 53 ± 4 mmHg·l−1·min−1). Percent change in splanchnic blood volume increased (7.5 ± 1.0 vs. 3.0 ± 11.5%, P < 0.05) after the onset of tilt. Upright tilt initially significantly increased thoracic, pelvic, and leg resistance in fainters, which subsequently decreased until faint. In fainters but not control subjects, normalized tidal volume (1 ± 0.1 to 2.6 ± 0.2, P < 0.05) and normalized minute ventilation increased throughout tilt (1 ± 0.2 to 2.1 ± 0.5, P < 0.05), whereas respiratory rate decreased (19 ± 1 to 15 ± 1 breaths/min, P < 0.05). Maximum tidal volume occurred just before fainting. The increase in minute ventilation was inversely proportionate to the decrease in ETCO2. Our data suggest that excessive splanchnic pooling and thoracic hypovolemia result in increased peripheral resistance and hyperpnea in simple postural faint. Hyperpnea and pulmonary stretch may contribute to the sympathoinhibition that occurs at the time of faint.
ATP/UTP activate cation-permeable channels with TRPC3/7 properties in rat cardiomyocytes
Authors: Alvarez Julio , Coulombe Alain , Cazorla Olivier , Ugur Mehmet , Rauzier Jean-Michel , Magyar Janos , Mathieu Eve-Lyne , Boulay Guylain , Souto Rafael , Bideaux Patrice , Salazar Guillermo , Rassendren François , Lacampagne Alain , Fauconnier Jérémy , Vassort Guy
Published: May 2008

Extracellular purines and pyrimidines have major effects on cardiac rhythm and contraction. ATP/UTP are released during various physiopathological conditions, such as ischemia, and despite degradation by ectonucleotidases, their interstitial concentrations can markedly increase, a fact that is clearly associated with arrhythmia. In the present whole cell patch-clamp analysis on ventricular cardiomyocytes isolated from various mammalian species, ATP and UTP elicited a sustained, nonselective cationic current, IATP. UDP was ineffective, whereas 2′(3′)- O-(4-benzoylbenzoyl)-ATP was active, suggesting that P2Y2receptors are involved. IATPresulted from the binding of ATP4−to P2Y2purinoceptors. IATPwas maintained after ATP removal in the presence of guanosine 5′-[γ-thio]triphosphate and was inhibited by U-73122, a PLC inhibitor. Single-channel openings are rather infrequent under basal conditions. ATP markedly increased opening probability, an effect prevented by U-73122. Two main conductance levels of 14 and 23 pS were easily distinguished. Similarly, in fura-2-loaded cardiomyocytes, Mn2+quenching and Ba2+influx were significant only in the presence of ATP or UTP. Adult rat ventricular cardiomyocytes expressed transient receptor potential channel TRPC1, -3, -4, and -7 mRNA and the TRPC3 and TRPC7 proteins that coimmunoprecipitated. Finally, the anti-TRPC3 antibody added to the patch pipette solution inhibited IATP. In conclusion, activation of P2Y2receptors, via a G protein and stimulation of PLCβ, induces the opening of heteromeric TRPC3/7 channels, leading to a sustained, nonspecific cationic current. Such a depolarizing current could induce cell automaticity and trigger the arrhythmic events during an early infarct when ATP/UTP release occurs. These results emphasize a new, potentially deleterious role of TRPC channel activation.
Physiological determinants of the pulmonary filtration coefficient
Authors: Parker James C. , Townsley Mary I.
Published: May 2008

Current emphasis on translational application of genetic models of lung disease has renewed interest in the measurement of the gravimetric filtration coefficient ( Kf) as a means to assess vascular permeability changes in isolated perfused lungs. The Kfis the product of the hydraulic conductivity and the filtration surface area, and is a sensitive measure of vascular fluid permeability when the pulmonary vessels are fully recruited and perfused. We have observed a remarkable consistency of the normalized baseline Kfvalues between species with widely varying body weights from mice to sheep. Uniformity of Kfvalues can be attributed to the thin alveolar capillary barrier required for gas exchange and the conserved matching of lung vascular surface area to the oxygen requirements of the body mass. An allometric correlation between the total lung filtration coefficient ( Kf,t) and body weight in several species ( r2= 1.00) had a slope that was similar to those reported for alveolar and pulmonary capillary surface areas and pulmonary diffusion coefficients determined by morphometric methods in these species. A consistent Kfis dependent on accurately separating the filtration and vascular volume components of lung weight gain, then Kfis a consistent and repeatable index of lung vascular permeability.
Somatostatin inhibits hepatic growth hormone receptor and insulin-like growth factor I mRNA expression by activating the ERK and PI3K signaling pathways
Authors: Hagemeister Alison L. , Sheridan Mark A.
Published: May 2008

Previously, we reported that somatostatins (SS) inhibit organismal growth by reducing hepatic growth hormone (GH) sensitivity and by inhibiting insulin-like growth factor I (IGF-I) production. In this study, we used hepatocytes isolated from rainbow trout to elucidate the mechanism(s) associated with the extrapituitary growth-inhibiting actions of SS. SS-14, a predominant SS isoform, stimulated tyrosine phosphorylation of several endogenous proteins, including extracellular signal-regulated kinase (ERK), a member the mitogen-activated protein kinase (MAPK) family, and protein kinase B (Akt), a downstream target of phosphatidylinositol 3-kinase (PI3K). SS-14 specifically stimulated the phosphorylation of both ERK 1/2 and Akt in a concentration-dependent fashion. This activation occurred within 5–15 min, then subsided after 1 h. The ERK inhibitor U0126 retarded SS-14-stimulated phosphorylation of ERK 1/2, whereas the PI3K inhibitor LY294002 blocked SS-14-stimulated phosphorylation of Akt. SS-14-inhibited expression of GH receptor (GHR) mRNA was blocked by U0126 but not by LY294002. By contrast, U1026 had no effect on SS-14 inhibition of GH-stimulated IGF-I mRNA expression, whereas LY294002 partially blocked the inhibition of GH-stimulated IGF-I mRNA expression by SS-14. These results indicate that SS-14-inhibited GHR expression is mediated by the ERK signaling pathway and that the PI3K/Akt pathway mediates, at least in part, SS-14 inhibition of GH-stimulated IGF-I expression.
AT1 receptor participates in the cardiac hypertrophy induced by resistance training in rats
Authors: Barauna Valerio G. , Magalhaes Flávio C. , Krieger Jose E. , Oliveira Edilamar M.
Published: May 2008

Resistance training is accompanied by cardiac hypertrophy, but the role of the renin-angiotensin system (RAS) in this response is elusive. We evaluated this question in 36 male Wistar rats divided into six groups: control ( n = 6); trained ( n = 6); control + losartan (10 mg·kg−1·day−1, n = 6); trained + losartan ( n = 6); control + high-salt diet (1%, n = 6); and trained + high-salt diet (1%, n = 6). High salt was used to inhibit the systemic RAS and losartan to block the AT1 receptor. The exercise protocol consisted of: 4 × 12 bouts, 5×/wk during 8 wk, with 65–75% of one repetition maximum. Left ventricle weight-to-body weight ratio increased only in trained and trained + high-salt diet groups (8.5% and 10.6%, P < 0.05) compared with control. Also, none of the pathological cardiac hypertrophy markers, atrial natriuretic peptide, and αMHC (α-myosin heavy chain)-to-βMHC ratio, were changed. ACE activity was analyzed by fluorometric assay (systemic and cardiac) and plasma renin activity (PRA) by RIA and remained unchanged upon resistance training, whereas PRA decreased significantly with the high-salt diet. Interestingly, using Western blot analysis and RT-PRC, no changes were observed in cardiac AT2 receptor levels, whereas the AT1 receptor gene (56%, P < 0.05) and protein (31%, P < 0.05) expressions were upregulated in the trained group. Also, cardiac ANG II concentration evaluated by ELISA remained unchanged (23.27 ± 2.4 vs. 22.01 ± 0.8 pg/mg, P > 0.05). Administration of a subhypotensive dose of losartan prevented left ventricle hypertrophy in response to the resistance training. Altogether, we provide evidence that resistance training-induced cardiac hypertrophy is accompanied by induction of AT1 receptor expression with no changes in cardiac ANG II, which suggests a local activation of the RAS consistent with the hypertrophic response.
Ghrelin secretion is not reduced by increased fat mass during diet-induced obesity
Authors: Qi Xiang , Reed Jason T. , Wang Guiyun , Han Song , Englander Ella W. , Greeley George H.
Published: May 2008

Ghrelin is a stomach hormone that stimulates growth hormone (GH) secretion, adiposity, and food intake. Gastric ghrelin production and secretion are regulated by caloric intake; ghrelin secretion increases during fasting, decreases with refeeding, and is reduced by diet-induced obesity. The aim of the present study was to test the hypotheses that 1) an increase in body adiposity will play an inhibitory role in the reduction of gastric ghrelin synthesis and secretion during chronic ingestion of a high-fat (HF) diet and 2) chronic ingestion of an HF diet will suppress the rise in circulating ghrelin levels in response to acute fasting. Adult male Sprague-Dawley rats were fed a standard AIN-76A (∼5–12% of calories from fat) or an HF (∼45% of calories from fat) diet. The effect of increased adiposity on gastric ghrelin homeostasis was assessed by comparison of stomach ghrelin production and plasma ghrelin levels in obese and nonobese rats fed the HF diet. HF diet-fed, nonobese rats were generated by administration of triiodothyronine to lower body fat accumulation. Our findings indicate that an increased fat mass per se does not exert an inhibitory effect on ghrelin homeostasis during ingestion of the HF diet. Additionally, the magnitude of change in plasma ghrelin in response to fasting was not blunted, indicating that a presumed, endogenous signal for activation of ingestive behavior remains intact, despite excess stored calories in HF-fed rats.
Effects of amiloride, benzamil, and alterations in extracellular Na+ on the rat afferent arteriole and its myogenic response
Authors: Wang Xuemei , Takeya Kosuke , Aaronson Philip I. , Loutzenhiser Kathy , Loutzenhiser Rodger
Published: May 2008

Recent studies have implicated epithelial Na+ channels (ENaC) in myogenic signaling. The present study was undertaken to determine if ENaC and/or Na+ entry are involved in the myogenic response of the rat afferent arteriole. Myogenic responses were assessed in the in vitro hydronephrotic kidney model. ENaC expression and membrane potential responses were evaluated with afferent arterioles isolated from normal rat kidneys. Our findings do not support a role of ENaC, in that ENaC channel blockers did not reduce myogenic responses and ENaC expression could not be demonstrated in this vessel. Reducing extracellular Na+ concentration ([Na+]o; 100 mmol/l) did not attenuate myogenic responses, and amiloride had no effect on membrane potential. Benzamil, an inhibitor of ENaC that also blocks Na+/Ca2+ exchange (NCX), potentiated myogenic vasoconstriction. Benzamil and low [Na+]o elicited vasoconstriction; however, these responses were attenuated by diltiazem and were associated with significant membrane depolarization, suggesting a contribution of mechanisms other than a reduction in NCX. Na+ repletion induced a vasodilation in pressurized afferent arterioles preequilibrated in low [Na+]o, a hallmark of NCX, and this response was reduced by 10 μmol/l benzamil. The dilation was eliminated, however, by a combination of benzamil plus ouabain, suggesting an involvement of the electrogenic Na+-K+-ATPase. In concert, these findings refute the premise that ENaC plays a significant role in the rat afferent arteriole and instead suggest that reducing [Na+]o and/or Na+ entry is coupled to membrane depolarization. The mechanisms underlying these unexpected and paradoxical effects of Na+ are not resolved at the present time.
Renal expression of exchange protein directly activated by cAMP (Epac) 1 and 2
Authors: Li Yuedan , Konings Irene B. M. , Zhao Jun , Price Leo S. , de Heer Emile , Deen Peter M. T.
Published: May 2008

In the kidney, many physiological processes of ion transport and cellular proliferation are mediated via cAMP, which classically activates protein kinase A (PKA). Recently, however, two new cAMP targets, the exchange protein directly activated by cAMP (Epac) 1 and 2, were identified, which mediate alternative pathways to PKA. To investigate their renal expression, antibodies specifically recognizing Epac1 and Epac2 were generated and used in rat immunohistochemistry with antibodies recognizing aquaporin-1 (AQP1), Tamm-Horsfall protein, Calbindin-D28K, and AQP2 to mark proximal tubules (PT)/thin descending limbs of Henle's loop (tDLH), thick ascending limbs of Henle's loop (TAL), distal convoluted tubule/connecting tubule (DCT/CNT), and the collecting duct (CD) principal cells, respectively. Epac1 and Epac2 were expressed at the brush border of PT cells but were absent from tDLH cells. In the TAL, Epac1 and Epac2 were expressed throughout the cells with some confinement toward the apical membrane. In the DCT/CNT, Epac1 was confined to the apical region of the cells, whereas Epac2 was mainly expressed in the apical and basolateral regions. In the CD, a dispersed Epac1 expression was found in intercalated cells only (cortical CD), principal and intercalated cells [outer medullary CD (OMCD)], and mainly AQP2-negative cells in the inner medullary CD (IMCD). In contrast, Epac2 expression was at the apical and basolateral membrane of cortical principal cells, dispersed and apical in the OMCD, and in all cells of the IMCD. A similar distribution for Epac1/2 was found in the human kidney. The observed expression in different tubular segments suggests a major role for Epac 1/2 in tubular transport physiology and cellular proliferation.
Potassium channel contributions to afferent arteriolar tone in normal and diabetic rat kidney
Authors: Troncoso Brindeiro Carmen M. , Fallet Rachel W. , Lane Pascale H. , Carmines Pamela K.
Published: May 2008

We previously reported an enhanced tonic dilator impact of ATP-sensitive K+channels in afferent arterioles of rats with streptozotocin (STZ)-induced diabetes. The present study explored the hypothesis that other types of K+channel also contribute to afferent arteriolar dilation in STZ rats. The in vitro blood-perfused juxtamedullary nephron technique was utilized to quantify afferent arteriolar lumen diameter responses to K+channel blockers: 0.1–3.0 mM 4-aminopyridine (4-AP; KVchannels), 10–100 μM barium (KIRchannels), 1–100 nM tertiapin-Q (TPQ; Kir1.1 and Kir3.x subfamilies of KIRchannels), 100 nM apamin (SKCachannels), and 1 mM tetraethylammonium (TEA; BKCachannels). In kidneys from normal rats, 4-AP, TEA, and Ba2+reduced afferent diameter by 23 ± 3, 8 ± 4, and 18 ± 2%, respectively, at the highest concentrations employed. Neither TPQ nor apamin significantly altered afferent diameter. In arterioles from STZ rats, a constrictor response to TPQ (22 ± 4% decrease in diameter) emerged, and the response to Ba2+was exaggerated (28 ± 5% decrease in diameter). Responses to the other K+channel blockers were similar to those observed in normal rats. Moreover, exposure to either TPQ or Ba2+reversed the afferent arteriolar dilation characteristic of STZ rats. Acute surgical papillectomy did not alter the response to TPQ in arterioles from normal or STZ rats. We conclude that 1) KV, KIR, and BKCachannels tonically influence normal afferent arteriolar tone, 2) KIRchannels (including Kir1.1 and/or Kir3.x) contribute to the afferent arteriolar dilation during diabetes, and 3) the dilator impact of Kir1.1/Kir3.x channels during diabetes is independent of solute delivery to the macula densa.
Endocannabinoid- and mGluR5-Dependent Short-Term Synaptic Depression in an Isolated Neuron/Bouton Preparation From the Hippocampal CA1 Region
Authors: Sheinin Anton , Talani Giuseppe , Davis Margaret I. , Lovinger David M.
Published: May 2008

Endocannabinoids released from the postsynaptic neuronal membrane can activate presynaptic CB1 receptors and inhibit neurotransmitter release. In hippocampal slices, depolarization of the CA1 pyramidal neurons elicits an endocannabinoid-mediated inhibition of γ-aminobutyric acid release known as depolarization-induced suppression of inhibition (DSI). Using the highly reduced neuron/synaptic bouton preparation from the CA1 region of hippocampus, we have begun to examine endocannabinoid-dependent short-term depression (STD) of inhibitory synaptic transmission under well-controlled physiological and pharmacological conditions in an environment free of other cells. Application of the CB1 synthetic agonist WIN55212 -2 and endogenous cannabinoids 2-AG and anandamide produced a decrease in spontaneous inhibitory postsynaptic current (sIPSC) frequency and amplitude, indicating the presence of CB1 receptors at synapses in this preparation. Endocannabinoid-dependent STD is different from DSI found in hippocampal slices and the neuron/bouton preparation from basolateral amygdala (BLA) since depolarization alone was not sufficient to induce suppression of sIPSCs. However, concurrent application of the metabotropic glutamate receptor (mGluR) agonist ( RS)-3,5-dihydroxyphenylglycine (DHPG) and postsynaptic depolarization resulted in a transient (30–50 s) decrease in sIPSC frequency and amplitude. Application of DHPG alone had no effect on sIPSCs. The depolarization/DHPG-induced STD was blocked by the CB1 antagonist SR141716A and the mGluR5 antagonist MPEP and was sensitive to intracellular calcium concentration. Comparing the present findings with earlier work in hippocampal slices and BLA, it appears that endocannabinoid release is less robust in isolated hippocampal neurons.
Time and Frequency Characteristics of Purkinje Cell Complex Spikes in the Awake Monkey Performing a Nonperiodic Task
Authors: Hakimian Shahin , Norris Scott A. , Greger Bradley , Keating Jeffrey G. , Anderson Charles H. , Thach W. Thomas
Published: May 2008

A number of studies have been interpreted to support the view that the inferior olive climbing fibers send periodic signals to the cerebellum to time and pace behavior. In a direct test of this hypothesis in macaques performing nonperiodic tasks, we analyzed continuous recordings of complex spikes from the lateral cerebellar hemisphere. We found no periodicity outside of a 100-ms relative refractory period.
Intracellular Recordings From Combination-Sensitive Neurons in the Inferior Colliculus
Authors: Peterson Diana Coomes , Voytenko Sergiy , Gans Donald , Galazyuk Alexander , Wenstrup Jeffrey
Published: May 2008

In vertebrate auditory systems, specialized combination-sensitive neurons analyze complex vocal signals by integrating information across multiple frequency bands. We studied combination-sensitive interactions in neurons of the inferior colliculus (IC) of awake mustached bats, using intracellular somatic recording with sharp electrodes. Facilitated combinatorial neurons are coincidence detectors, showing maximum facilitation when excitation from low- and high-frequency stimuli coincide. Previous work showed that facilitatory interactions originate in the IC, require both low and high frequency–tuned glycinergic inputs, and are independent of glutamatergic inputs. These results suggest that glycinergic inputs evoke facilitation through either postinhibitory rebound or direct depolarizing mechanisms. However, in 35 of 36 facilitated neurons, we observed no evidence of low frequency–evoked transient hyperpolarization or depolarization that was closely related to response facilitation. Furthermore, we observed no evidence of shunting inhibition that might conceal inhibitory inputs. Since these facilitatory interactions originate in IC neurons, the results suggest that inputs underlying facilitation are electrically segregated from the soma. We also recorded inhibitory combinatorial interactions, in which low frequency sounds suppress responses to higher frequency signals. In 43% of 118 neurons, we observed low frequency–evoked hyperpolarizations associated with combinatorial inhibition. For these neurons, we conclude that low frequency–tuned inhibitory inputs terminate on neurons primarily excited by high-frequency signals; these inhibitory inputs may create or enhance inhibitory combinatorial interactions. In the remainder of inhibited combinatorial neurons (57%), we observed no evidence of low frequency–evoked hyperpolarizations, consistent with observations that inhibitory combinatorial responses may originate in lateral lemniscal nuclei.
Dynamic Changes in the Cortex-Basal Ganglia Network After Dopamine Depletion in the Rat
Authors: Dejean Cyril , Gross Christian E. , Bioulac Bernard , Boraud Thomas
Published: May 2008

It is well established that parkinsonian syndrome is associated with alterations in the temporal pattern of neuronal activity and local field potentials in the basal ganglia (BG). An increase in synchronized oscillations has been observed in different BG nuclei in parkinsonian patients and animal models of this disease. However, the mechanisms underlying this phenomenon remain unclear. This study investigates the functional connectivity in the cortex-BG network of a rodent model of Parkinson's disease. Single neurons and local field potentials were simultaneously recorded in the motor cortex, the striatum, and the substantia nigra pars reticulata (SNr) of freely moving rats, and high-voltage spindles (HVSs) were used to compare signal transmission before and after dopaminergic depletion. It is shown that dopaminergic lesion results in a significant enhancement of oscillatory synchronization in the BG: the coherence between pairs of structures increased significantly and the percentage of oscillatory auto- and cross-correlograms. HVS episodes were also more numerous and longer. These changes were associated with a shortening of the latency of SNr response to cortical activation, from 40.5 ± 4.8 to 10.2 ± 1.07 ms. This result suggests that, in normal conditions, SNr neurons are likely to be driven by late inputs from the indirect pathway; however, after the lesion, their shorter latency also indicates an overactivation of the hyperdirect pathway. This study confirms that neuronal signal transmission is altered in the BG after dopamine depletion but also provides qualitative evidence for these changes at the cellular level.
Stokes Efficiency of Molecular Motor‐Cargo Systems
Authors: Wang Hongyun , Zhou Hong
Published: May 2008

A molecular motor utilizes chemical free energy to generate a unidirectional motion
through the viscous fluid. In many experimental settings and biological settings, a
molecular motor is elastically linked to a cargo. The stochastic motion of a molecular
motor‐cargo system is governed by a set of Langevin equations, each corresponding to
an individual chemical occupancy state. The change of chemical occupancy state is
modeled by a continuous time discrete space Markov process. The probability density
of a motor‐cargo system is governed by a two‐dimensional Fokker‐Planck equation. The
operation of a molecular motor is dominated by high viscous friction and large thermal
fluctuations from surrounding fluid. The instantaneous velocity of a molecular motor
is highly stochastic: the past velocity is quickly damped by the viscous friction and
the new velocity is quickly excited by bombardments of surrounding fluid molecules.
Thus, the theory for macroscopic motors should not be applied directly to molecular
motors without close examination. In particular, a molecular motor behaves differently
working against a viscous drag than working against a conservative force. The Stokes
efficiency was introduced to measure how efficiently a motor uses chemical free energy
to drive against viscous drag. For a motor without cargo, it was proved that the Stokes
efficiency is bounded by 100% [H. Wang and G. Oster, (2002)].
Here, we present a proof for the general motor‐cargo system.
Iron Oxide Doped Alumina‐Zirconia Nanoparticle Synthesis by Liquid Flame Spray from Metal Organic Precursors
Authors: Nikkanen Juha-Pekka , Keskinen Helmi , Aromaa Mikko , Järn Mikael , Kanerva Tomi , Levänen Erkki , Mäkelä Jyrki M. , Mäntylä Tapio
Published: May 2008

The liquid flame spray (LFS) method was used to make iron oxide doped alumina‐zirconia nanoparticles. Nanoparticles were generated using a turbulent, high‐temperature (Tmax  ~ 3000 K) H2‐O2 flame. The precursors were aluminium‐isopropoxide, zirconium‐n‐propoxide, and ferrocene in xylene solution. The solution was atomized into micron‐sized droplets by high velocity H2 flow and introduced into the flame where nanoparticles were formed. The particle morphology, size, phase, and chemical composition were determined by TEM, XRD, XPS, and N2‐adsorption measurements. The collected particulate material consists of micron‐sized aggregates with nanosized primary particles. In both doped and undoped samples, tetragonal phase of zirconia was detected in room temperature while alumina was found to be noncrystalline. In the doped powder, Fe was oxidized to Fe2O3. The primary particle size of collected sample was approximately from 6 nm to 40 nm. Doping was observed to increase the specific surface area of the powder from 39 m2/g to 47 m2/g.
Worms and the Treatment of Inflammatory Bowel Disease: Are Molecules the Answer?
Authors: Ruyssers Nathalie E. , De Winter Benedicte Y. , De Man Joris G. , Loukas Alex , Herman Arnold G. , Pelckmans Paul A. , Moreels Tom G.
Published: May 2008

The lack of exposure to helminth infections, as a result of improved living standards and medical conditions, may have contributed to the increased incidence of IBD in the developed world. Epidemiological, experimental, and clinical data sustain the idea that helminths could provide protection against IBD. Studies investigating the underlying mechanisms by which helminths might induce such protection have revealed the importance of regulatory pathways, for example, regulatory T-cells. Further investigation on how helminths influence both innate and adaptive immune reactions will shed more light on the complex pathways used by helminths to regulate the hosts immune system. Although therapy with living helminths appears to be effective in several immunological diseases, the disadvantages of a treatment based on living parasites are explicit. Therefore, the identification and characterization of helminth-derived immunomodulatory molecules that contribute to the protective effect could lead to new therapeutic approaches in IBD and other immune diseases.
Anticancer Properties of PPARα‐Effects on Cellular Metabolism and Inflammation
Authors: Grabacka Maja , Reiss Krzysztof
Published: May 2008

Peroxisome proliferator‐activated receptors (PPARs) have lately attracted much attention as therapeutic targets. Previously, PPAR ligands were associated with the treatment of diabetes, hyperlipidemia and cardiovascular diseases, as they modulate the expression of genes regulating glucose and lipid metabolism. Recently, PPAR ligands have been also considered as potential anticancer agents, with relatively low systemic toxicity. The emerging evidence for antiproliferative, proapoptotic, antiinflammatory and potential antimetastatic properties of PPARα ligands prompted us to discuss possible roles of PPARα in tumor suppression. PPARα activation can target cancer cells energy balance by blocking fatty acid synthesis and by promoting fatty acid β‐oxidation. In the state of limited nutrient availability, frequently presents in the tumor microenvironment, PPARα cooperates with AMP‐dependent protein kinase in: (i) repressing oncogenic Akt activity, (ii) inhibiting cell proliferation, and (iii) forcing glycolysis‐dependent cancer cells into “metabolic catastrophe.” Other potential anticancer effects of PPARα include suppression of inflammation, and upregulation of uncoupling proteins (UCPs), which attenuates mitochondrial reactive oxygen species production and cell proliferation. In conclusion, there are strong premises that the low‐toxic and well‐tolerated PPAR ligands should be considered as new therapeutic agents to fight disseminating cancer, which represents the major challenge for modern medicine and basic research.
Biblical Feminisms: Knowledge, Theory and Politics in the Study of Women in the Hebrew Bible
Authors: Fuchs Esther
Published: May 2008

The proliferation of biblical feminist interpretations and readings in the last two decades suggests that we may witness the emergence of an autonomous field of studies. In this essay I suggest that in order for such a field to emerge as an autonomous and thriving area of academic inquiry we must begin to think theoretically and critically about the work that has been done, the objectives of this work and the relationships between and among various approaches to the field. In this essay I call for a rigorous and critical biblical feminist epistemology that seeks to address on every turn the question of knowledge production as power; on the other hand I call for a radical democratization of the field and the questioning of any and all orthodoxies and hierarchies that may have already emerged in the field. The first "centripetal" approach insists on clarifying the foundations of the field, establishing genealogies of knowledge and an evolutionary trajectory, crediting and acknowledging theoretical points of origination. Respect for precedence and antecedence is required so as to avoid repetition, imitation and dilution. The second "centrifugal" approach emphasizes the need for interrogating, displacing and destabilizing foundational paradigms in Biblical Studies at large and for the continued questioning of stable identities of "women" as subjects and objects of inquiry. A vigorous field of Feminist Biblical Studies ought to deploy both approaches opening the way to both debate and contestation between various feminist approaches to the Bible on the one hand and to dialogue and alliance between methodologically, theoretically, politically and culturally different approaches on the other.
Eden for Cyborgs: Ecocriticism and Genesis 2–3
Authors: Walker-Jones Arthur
Published: May 2008

This article begins by introducing the work of a leading feminist theorist, Donna Haraway, especially her classic article, "A Manifesto for Cyborgs," and its relevance for ecocriticism of the Hebrew Bible. Building on the work of Hilary Klein, Haraway argues that Marxism, feminism and technoscience often work out of origin stories that reinscribe the dualisms that feminists seek to overcome. She refers to all contemporary origin stories as Eden stories. Her analysis of Jane Goodall's work at Gombe is an example. Haraway seeks myths or figures that blur the boundaries between the dualisms that structure oppression, and that may help imagine a more livable future. Much of her work is with "monsters" because they often define the limits of community in Western culture. For instance, although the cyborg has its origin in a horrible myth of patriarchal capitalism about destruction of Earth and escape into space, she suggests the cyborg has the potential to subvert its origin because it blurs the boundaries between humanity and nature and redefines both. The serpent in the Garden of Eden story is such a boundary transgressing monster. It blurs the boundaries between God and nature, and humanity and nature. With the help of the snake, the humans acquire the discernment to fulfill their preordained vocation to serve and protect Earth and choose reality and full humanity with all its ambiguities. An interpretation of the story that focuses on the serpent could decenter heterosexist and anthropocentric readings and serve as a subversive figure for the future of the Earth community.
La manière de raconter et l'enjeu du récit. Jérémie présente Ananias en Jer 28,1 TM et 35,1 LXX
Authors: Di Pede Elena
Published: May 2008

The way in which a story is told determines the aim and the significant elements of the particular telling which is thus produced, as any telling of a story comes down to putting into action a narrative strategy with a view to achieving a certain effect on the reader. When one has two versions of the same story, one can, by comparison, assess the strategy used in each one. That is the aim of the present note, which analyses the presentation that Jeremiah offers of his adversary Hananiah in Jer 28,1 (mt)/35,1 (lxx).
An Early Chinese Calendar Chart: Kuan-Tzu, Iii, 8 (Yu Kuan ? ?) 1)
Authors: Rickett W. Allyn
Published: May 2008

The Kuan-tzu is a collection of essays dating roughly from the fourth to the second century B.C. They were edited in their present form by Liu Hsiang about 26 B.C. This essay is composed of a seasonal calendar coupled with a treatise on military strategy. The arrangement of the text indicates it once formed the content of an early calendar chart.
Experimental No. 223, a newspaper typeface, designed by W.A. Dwiggins
Authors: Unger Gerard
Published: May 2008

From 1926 onwards, beginning with their introduction of the 'Ionic' typeface, the Mergenthaler Linotype composing machine manufacturers, prompted by their director C.H. Griffith, continued to develop the so-called 'Legibility group' of typefaces for newspapers. These types, soon closely copied by their competitors, have indeed 'conquered the world': they practically determine the look of contemporary newspapers. A very large portion of our daily intake of information comes through these types. Within the Linotype company, its principal artist-under-contract, W.A. Dwiggins (author, among other things, of the 'Electra' and 'Caledonia' book faces) objected to the design quality of the 'Legibility group' and proposed solutions of his own. The Dutch typedesigner Gerard Unger has examined the Dwiggins-Gri f fith correspondence kept in the library of the University of Kentucky at Lexington and in the Boston Public Library. He traces the development of Dwiggins's counter-proposals and explains why they did not succeed in driving out the ubiquitous derivates of the Ionic model-a feat, by the way, which Stanley Morison's 'Times New Roman', conceived as a newspaper type but actually today's most successful type for books and periodicals, failed to perform either. - Ed.
Reflections on Leading and Learning for Change
Authors: Kruse Sharon D.
Published: May 2008

This essay summarizes the key themes of each article in this special issue of Education and Urban Society and addresses complimentary issues raised within the articles. Each article addresses an important issue facing school leaders—perennially low-performing schools, enacting instructional leadership in the face of accountability, the district's role in school improvement, and effective practices of instruction and assessment. Together they suggest that leading school improvement is more than the process of leading pedagogical adoptions, professional development, or making sound decisions. They also suggest that leading in low-performing schools requires sustained attention to both the people within the system and the context in which the system operates.