bluuebunny/crossref_metadata_2025 huggingface dataset:
Single crystals of bacterial and synthetic poly(3-hydroxyvalerate)
Authors: Marchessault R. H. , Debzi E. M. , Revol J. F. , Steinbüchel A.
Published: October 2009

Lamellar, folded-chain single crystals of bacterial homopolymer, of synthetic racemic poly(β-hydroxyvalerate) (PHV), and of bacterial poly(β-hydroxybutyrate-co-(β-hydroxyvalerate) (P(HB-co-HV)), with high HV content (superior to 77 mol%) were obtained from dilute ethanolic solutions. They all exhibited the same square shape as opposed to the characteristic lath shape of poly(β-hydroxybutyrate) single crystals and P(HB-co-HV) single crystals with low HV content. The electron diffraction patterns recorded from selected areas of these single crystals were identical and allowed the comparison of our observed basal unit cell parameters with those derived from X-ray fibre diffraction. The results provided a visual and quantitative confirmation of the isodimorphism phenomenon and confirmed the P212121 orthorhombic symmetry. The lower perfection in the morphology of the single crystals from the synthetic PHV homopolymer than in those from the bacterial samples is attributable to a stereoblock segregation during the crystallization according to block chirality.Key words: poly(3-hydroxyvalerate), single crystals, bacterial polyester, electron diffraction, isodimorphism.
Morphology and biodegradability of a binary blend of poly((R)-3-hydroxybutyric acid) and poly((R,S)-lactic acid)
Authors: Koyama Naoyuki , Doi Yoshiharu
Published: October 2009

The miscibility, morphology, and biodegradability of a binary blend of bacterial poly((R)-3-hydroxybutyric acid) (P((R)-3HB); Mn = 300 000) with atactic poly((R,S)-lactic acid) (P((R,S)-LA); Mn = 9000) were studied by means of differential scanning calorimetry, optical microscopy, scanning electron microscopy, and hydrolysis with and without enzyme. Differential scanning calorimetry revealed that a P((R)-3HB)–P((R,S)-LA) blend had a single glass-transition temperature for all proportions of the components. The spherulites of P((R)-3HB) were volume filled in the blend films, indicating the inclusion of amorphous P((R,S)-LA) within the spherulites. The spherulitic growth rate decreased with an increase in the content of P((R,S)-LA). These results indicate that the P((R)-3HB)–P((R,S)-LA) blend is miscible in the melt and in the amorphous state. The enzymatic hydrolysis of P((R)-3HB)–P((R,S)-LA) blend films was carried out at 37 °C for 19 h in 0.1 M potassium phosphate buffer (pH 7.4) with an extracellular poly(hydroxybutyrate) depolymerase from Alcaligenes faecalis T1. The rate of enzymatic surface erosion decreased with increasing P((R,S)-LA) content in the blend films. The simple hydrolysis of P((R)-3HB)–P((R,S)-LA) blend films without enzyme was also conducted at 37 °C in a 0.01 M potassium phosphate buffer (pH 7.4) for 150 days. The hydrolytic scission of P((R)-3HB) polymer chains was accelerated by blending with P((R,S)-LA). However, the rate of enzymatic hydrolysis was much faster than the rate of nonenzymatic hydrolysis.Key words: poly((R)-3-hydroxybutyric acid), poly((R,S)-lactic acid), miscibility, morphology, biodegradability.
ON MODEL PREDICTIVE CONTROL OF QUASI-RESONANT CONVERTERS
Authors: TAHAMI FARZAD , EBAD MEHDI
Published: October 2009

In this paper, different model predictive control synthesis frameworks are examined for DC–DC quasi-resonant converters in order to achieve stability and desired performance. The performances of model predictive control strategies which make use of different forms of linearized models are compared. These linear models are ranging from a simple fixed model, linearized about a reference steady state to a weighted sum of different local models called multi model predictive control. A more complicated choice is represented by the extended dynamic matrix control in which the control input is determined based on the local linear model approximation of the system that is updated during each sampling interval, by making use of a nonlinear model. In this paper, by using and comparing these methods, a new control scheme for quasi-resonant converters is described. The proposed control strategy is applied to a typical half-wave zero-current switching QRC. Simulation results show an excellent transient response and a good tracking for a wide operating range and uncertainties in modeling.
A DIRECT SEARCH METHOD FOR WORST CASE ANALYSIS AND YIELD OPTIMIZATION OF INTEGRATED CIRCUITS
Authors: CIJAN GREGOR , TUMA TADEJ , BŰRMEN ÁRPÁD
Published: October 2009

Yield maximization is an important aspect in the design of integrated circuits. A prerequisite for its automation is a reliable and fast worst performance analysis which results in corners that can be used in the process of circuit optimization. We formulate the constrained optimization problem for finding the worst performance of an integrated circuit and develop a direct search method for solving it. The algorithm uses radial steps and rotations for enforcing the inequality constraint. We demonstrate the performance of the proposed algorithm on real world design examples of integrated circuits. The results indicate that the algorithm solves the worst performance problem in an efficient manner. The proposed algorithm was also successfully used in the process of yield maximization, resulting in a 99.65% yield.
TRANSIENT RESPONSE OF A DISTRIBUTED RLC INTERCONNECT BASED ON DIRECT POLE EXTRACTION
Authors: CHEN GUOQING , FRIEDMAN EBY G.
Published: October 2009

With higher operating frequencies, transmission lines are required to model global on-chip interconnects. In this paper, an accurate and efficient solution for the transient response at the far end of a transmission line based on a direct pole extraction of the system is proposed. Closed form expressions of the poles are developed for two special interconnect systems: an RC interconnect and an RLC interconnect with zero driver resistance. By performing a system conversion, the poles of an interconnect system with general circuit parameters are solved. The Newton–Raphson method is used to further improve the accuracy of the poles. Based on these poles, closed form expressions for the step and ramp response are determined. Higher accuracy can be obtained with additional pairs of poles. The computational complexity of the model is proportional to the number of pole pairs. With two pairs of poles, the average error of the 50% delay is 1% as compared with Spectre simulations. With ten pairs of poles, the average error of the 10%-to-90% rise time and the overshoots is 2% and 1.9%, respectively. Frequency dependent effects are also successfully included in the proposed method and excellent match is observed between the proposed model and Spectre simulations.
EFFECTS OF PARAMETER VARIATIONS ON TIMING CHARACTERISTICS OF CLOCKED REGISTERS
Authors: ROBERTS WILLIAM R. , VELENIS DIMITRIOS
Published: October 2009

Violations in the timing constraints of a clocked register can cause a synchronous system to malfunction. The effects of parameter variations on the timing characteristics of registers that determine the timing constraints are investigated in this paper. The sensitivity of the setup time and data propagation delay to variations in power supply voltage, temperature, and gate oxide thickness is demonstrated for four different register designs. Furthermore, design modifications are proposed that enhance the robustness of each register to variation effects.
IMPROVED POWER-EFFICIENT RNMC TECHNIQUE WITH VOLTAGE BUFFER AND NULLING RESISTORS FOR LOW-POWER HIGH-LOAD THREE-STAGE AMPLIFIERS
Authors: MARANO DAVIDE , PALUMBO GAETANO , PENNISI SALVATORE
Published: October 2009

This work proposes and develops an original compensation approach for low-power three-stage operational transconductance amplifiers driving large capacitive loads. The proposed solution is based on the basic reversed nested Miller compensation and exploits a voltage buffer and two nulling resistors in the compensation network, along with a feedforward stage to improve slewing and settling performance. A well-defined design procedure using the loop gain phase margin as the main design parameter is also developed. SPECTRE simulations on a three-stage amplifier are carried out and are found to be in excellent agreement with the theoretical analysis, showing a significant improvement of the proposed approach over traditional compensation strategies in terms of small-signal and large-signal performance. Monte Carlo simulation results finally prove the proposed technique to be well-guarded against process parameter variations.
ODD-PARITY BANDS OF 108, 110, 112Ru
Authors: LUO Y. X. , ZHU S. J. , HAMILTON J. H. , RAMAYYA A. V. , GOODIN C. , LI K. , CHE X. L. , HWANG J. K. , LEE I. Y. , JIANG Z. , TER-AKOPIAN G. M. , DANIEL A. V. , STOYER M. A. , DONANGELO R. , FRAUENDORF S. , DIMITROV V. , ZHANG JING-YE , COLE J. D. , STONE N. J. , RASMUSSEN J. O.
Published: October 2009

Two similar sets of odd-parity bands are observed in each of three even–even neighbors, 108, 110, 112 Ru , from a study of prompt spontaneous-fission gamma rays at Gammasphere. A careful study of the odd-parity levels of these nuclei shows evidence for the features of chiral doubling. Comparisons are made with reported other candidates for chiral doubling.
EVEN-PARITY BANDS OF 108, 110, 112Ru
Authors: ZHU S. J. , LUO Y. X. , HAMILTON J. H. , RAMAYYA A. V. , CHE X. L. , JIANG Z. , HWANG J. K. , WOOD J. L. , STOYER M. A. , DONANGELO R. , COLE J. D. , GOODIN C. , RASMUSSEN J. O.
Published: October 2009

High-spin, even-parity bands in neutron-rich 108, 110, 112 Ru nuclei were reinvestigated and considerably expanded by measuring many-fold prompt γ-ray coincidence events following the spontaneous fission of 252 Cf with Gammasphere. Our high statistics data allow us to detect weaker transitions and bands not previously published. Also, gamma branching ratios, which are important for theory, are carefully measured from all levels. In 110 Ru , we find a doubling of levels for both ground and quasi-gamma bands above the 8+ levels. There are likely two-phonon quasi-gamma bands in 110, 112 Ru , as well as a bandhead level in 108 Ru . The odd–even spin energy band staggering observed in the quasi-gamma bands in 108, 110, 112 Ru and the doubling of levels in 110 Ru present a challenge to theory.
PAIRING CORRELATIONS WITH RESONANT CONTINUUM EFFECT IN THE RMF + ACCC + BCS APPROACH
Authors: ZHANG S. S.
Published: October 2009

The relativistic mean field (RMF) + analytic continuation in the coupling constant (ACCC) + Bardeen–Cooper–Schrieffer (BCS) approach is first presented to describe exotic nuclei by taking into account the resonant continuum effect in pairing correlations. Constant pairing strength is used in BCS approximation. Resonance parameters and wave functions are extracted from effective ACCC approach within the framework of the self-consistent RMF theory. The pairing energies, pairing correlation energies, binding energies, two-neutron separation energies, neutron rms radii, and neutron densities for neutron-rich even–even Ni isotopes are explored in the RMF + ACCC + BCS approach with NL3 effective interaction. It shows that the results are in good agreement with those of other theoretical approaches.
FUZZY GROUP DECISION MAKING MODEL BASED ON CREDIBILITY THEORY AND GRAY RELATIVE DEGREE
Authors: RAO CONGJUN , PENG JIN
Published: October 2009

In this paper, the problems of fuzzy multi-attribute group decision making in which the attribute values are given in the form of linguistic fuzzy numbers are studied. First of all, a new method called fuzzy dominance is given for ranking trapezoidal fuzzy numbers based on the credibility theory. Then the TOWA operator is presented to aggregate the trapezoidal fuzzy numbers. Furthermore, a new model is presented for the problems of fuzzy multi-attribute group decision making via TOWA operator, fuzzy dominance method and gray relative degree. Finally, a decision-making example is given to demonstrate the feasibility and rationality of this new model.
Formal methods
Authors: Woodcock Jim , Larsen Peter Gorm , Bicarregui Juan , Fitzgerald John
Published: October 2009

Formal methods use mathematical models for analysis and verification at any part of the program life-cycle. We describe the state of the art in the industrial use of formal methods, concentrating on their increasing use at the earlier stages of specification and design. We do this by reporting on a new survey of industrial use, comparing the situation in 2009 with the most significant surveys carried out over the last 20 years. We describe some of the highlights of our survey by presenting a series of industrial projects, and we draw some observations from these surveys and records of experience. Based on this, we discuss the issues surrounding the industrial adoption of formal methods. Finally, we look to the future and describe the development of a Verified Software Repository, part of the worldwide Verified Software Initiative. We introduce the initial projects being used to populate the repository, and describe the challenges they address.
Automated deduction for verification
Authors: Shankar Natarajan
Published: October 2009

Automated deduction uses computation to perform symbolic logical reasoning. It has been a core technology for program verification from the very beginning. Satisfiability solvers for propositional and first-order logic significantly automate the task of deductive program verification. We introduce some of the basic deduction techniques used in software and hardware verification and outline the theoretical and engineering issues in building deductive verification tools. Beyond verification, deduction techniques can also be used to support a variety of applications including planning, program optimization, and program synthesis.
Software model checking
Authors: Jhala Ranjit , Majumdar Rupak
Published: October 2009

We survey recent progress in software model checking.
Building bridges
Authors: Westman Hans
Published: October 2009

What discipline in science, the arts or technology is truly isolated? The more one delves into their mysteries it becomes clear how inter-disciplinary they are. The mind jumps from one impression to the next in determining how existence is constructed. Though the perception may be subjective, it is an experience that is shared by many.

Science, the arts and technology are three separate disciplines, but have more in common than meets the eye. They are different lenses from which to observe reality.

We may see things differently, but if we share our insights, we build bridges and broaden our understanding.

This is the theme for the May 2009 issue of the SIGGRAPH e-quarter "Computer Graphics", emphasizing the importance of collaboration to improve the way computer graphics is used in different ways.

Elizabeth A. Rega, Department of Anatomy, Western University of Heath Sciences and Stuart S. Sumida, Department of Biology, California State University of Heath Sciences, have written an article together entitled "Anatomical Considerations in Facial Motion Capture", stressing the importance of understanding inherent traits of human facial expression to improve motion capture performance.

"iVisit Agitating for the Evolution of Fixed-mobile Tele-presence and Augmented Reality" by Orang Dialameh, CEO of iVisit, LLC introduces how current mobile video-calling software, spearheaded by CU-SeeMe creator Tim Dorcey, is taking advantage of the HTC (High Tech Computers) smart phone and pocket PC devices to assist doctors in meeting and treating patients remotely and helping persons who are visually impaired.

In the article "A Survey of BRDF Models for Computer Graphics" Murat Kurt, Ege University, International Computer Institute, Turkey and Dave Edwards, University of Utah, Salt Lake City, Utah, survey the most popular BRDF representations introduced so far and analyzed the most recent trends in this area. This article follows up an earlier article entitle "Representing BRDFs using SOMs and MANs", also written by Murat Kurt together with Muhammed Gókhan Cinsdikici, Ege University, International Computer Institute, Turkey.

Contributor Carlos D. Correa has written an informative article entitled "Visualizing What Lies Inside" for VisFiles, a very interesting read. My thanks to Kwan-Liu Ma for his continued solicitation of meaningful content for this section of the newsletter.

In conclusion, Jack Lew, Director of Collaborations at the Center for Emerging Media, University of Central Florida, comes full circle through his submission to Education entitled "Connecting the Dots by Crossing Borders", sharing how he, in his new position, sees scientists, artists and technologists collaborating and exploring new solutions in this field we broadly identify as computer graphics. Jack also contributed with the organizational chart used in the design of this issue's cover illustration.
GT
Authors: Gringoli F. , Salgarelli Luca , Dusi M. , Cascarano N. , Risso F. , claffy k. c.
Published: October 2009

Much of Internet traffic modeling, firewall, and intrusion detection research requires traces where some ground truth regarding application and protocol is associated with each packet or flow. This paper presents the design, development and experimental evaluation of gt, an open source software toolset for associating ground truth information with Internet traffic traces. By probing the monitored host's kernel to obtain information on active Internet sessions, gt gathers ground truth at the application level. Preliminary experimental results show that gt's effectiveness comes at little cost in terms of overhead on the hosting machines. Furthermore, when coupled with other packet inspection mechanisms, gt can derive ground truth not only in terms of applications (e.g., e-mail), but also in terms of protocols (e.g., SMTP vs. POP3).
Comparing the performance of concurrent linked-list implementations in Haskell (abstract only)
Authors: Sulzmann Martin , Lam Edmund S.L. , Marlow Simon
Published: October 2009

Haskell has a rich set of synchronization primitives for implementing shared-state concurrency abstractions, ranging from the very high level (Software Transactional Memory) to the very low level (mutable variables with atomic read-modifywrite).

In this paper we perform a systematic comparison of these different concurrent programming models by using them to implement the same abstraction: a concurrent linked-list. Our results are somewhat surprising: there is a full two orders of magnitude difference in performance between the slowest and the fastest implementation. Our analysis of the performance results gives new insights into the relative performance of the programming models and their implementation.

Finally, we suggest the addition of a single primitive which in our experiments improves the performance of one of the STM-based implementations by more than a factor of 7.
Making the computer accessible to mentally retarded adults
Authors: Robertson Gretchen L. , Hix Deborah
Published: October 2009

Little research has been conducted on how to teach computer skills to developmentally disabled adults. A head counselor at a home for mentally retarded adults, who served as the inspiration for this article, was an enthusiastic personal computer user who tried to share computer instruction with home residents. Efforts at using commercial applications designed for young children were unsuccessful. Residents briefly watched the counselor use the applications, then lost interest. Staff members had neither the time nor the user interface background to investigate which applications and user interaction design factors might make computers accessible to home residents. In this article, we describe our empirical investigation of computer use among moderately developmentally disabled individuals. We investigated the input devices preferred, and the user interaction design issues to be considered when designing or selecting applications for this population.
Development infrastructure characteristics and process capability
Authors: Patnayakuni Ravi , Rai Arun
Published: October 2009

A substantial portion of most organizational budgets goes toward developing IT applications. Despite the existence of many tools and methodologies, Information Systems Departments (ISDs) continue to face burgeoning costs and delays. In this article, we explore methods of improving the productivity and effectiveness of the application development process using the Capability Maturity Model (CMM) by the Software Engineering Institute (SEI) at Carnegie Mellon University as a benchmark for process maturity levels.
Data quality assessment
Authors: Pipino Leo L. , Lee Yang W. , Wang Richard Y.
Published: October 2009

How good is a company's data quality? Answering this question requires usable data quality metrics. Currently, most data quality measures are developed on an ad hoc basis to solve specific problems [6, 8], and fundamental principles necessary for developing usable metrics in practice are lacking. In this article, we describe principles that can help organizations develop usable data quality metrics.
Augmented bladder urothelial polyamine signaling and block of BK channel in the pathophysiology of overactive bladder syndrome
Authors: Li Mingkai , Sun Yan , Simard J. Marc , Wang Jian-Ying , Chai Toby C.
Published: October 2009

Overactive bladder syndrome (OAB) is an idiopathic condition characterized by urinary urgency and urge incontinence. Detrusor overactivity has been traditionally described as the physiologic mechanism for OAB. However, the bladder urothelium (BU) may also be involved in the pathophysiology. This study measured polyamine signaling and its downstream effects on membrane conductivity in bladder urothelial cells (BUC) obtained from asymptomatic and OAB subjects. Immunohistofluorescence was used to measure ornithine decarboxylase (ODC) expression in BU. BUC, cultured from BU biopsies, were used for electrophysiologic studies. dl-α-Difluoromethylornithine (DFMO), spermine, or spermidine was used to modulate polyamine signaling in BUC. Results showed ODC overexpression in OAB BU. In OAB BUC, whole cell and cell-attached configuration showed significantly decreased currents. Using inside-out patches, outward currents increased significantly, suggesting a cytoplasmic source of the outward current block in OAB BUC. In control BUC, outward currents were mediated by the large-conductance calcium-activated potassium (BK) channel due to calcium dose-dependence and block by iberiotoxin. Spermidine and spermine blocked the outward current in normal BUC in dose-dependent fashion. Conversely, DFMO significantly increased ( P < 0.01) outward currents in OAB BUC both in cell-attached and in whole cell configuration. The outward currents in DFMO-treated-OAB BUC could be significantly reduced ( P < 0.05) by adding back spermidine and spermine. These data suggest that polyamine signaling is upregulated in OAB urothelium and OAB BUC. Furthermore, polyamines in BUC block the BK channel. Targeting of bladder urothelial polyamine signaling may represent a novel approach for OAB treatment based on pathophysiologic mechanisms.
CaMKK is an upstream signal of AMP-activated protein kinase in regulation of substrate metabolism in contracting skeletal muscle
Authors: Abbott Marcia J. , Edelman Arthur M. , Turcotte Lorraine P.
Published: October 2009

Multiple signals have been shown to be involved in regulation of fatty acid (FA) and glucose metabolism in contracting skeletal muscle. This study aimed to determine whether a Ca2+-stimulated kinase, CaMKK, is involved in regulation of contraction-induced substrate metabolism and whether it does so in an AMP-activated protein kinase (AMPK)-dependent manner. Rat hindlimbs were perfused at rest ( n = 16), with 3 mM caffeine ( n = 15), with 2 mM 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside (AICAR; n = 16), or during moderate-intensity muscle contraction (MC; n = 14) and with or without 5 μM STO-609, a CaMKK inhibitor. FA uptake and oxidation increased ( P < 0.05) 64% and 71% by caffeine, 42% and 93% by AICAR, and 65% and 143% by MC. STO-609 abolished ( P < 0.05) caffeine- and MC-induced FA uptake and oxidation but had no effect with AICAR treatment. Glucose uptake increased ( P < 0.05) 104% by caffeine, 85% by AICAR, and 130% by MC, and STO-609 prevented the increase in glucose uptake in caffeine and muscle contraction groups. CaMKKβ activity increased ( P < 0.05) 113% by caffeine treatment and 145% by MC but was not affected by AICAR treatment. STO-609 prevented the caffeine- and MC-induced increase in CaMKKβ activity. Caffeine, AICAR, and MC increased ( P < 0.05) AMPKα2 activity by 295%, 11-fold, and 7-fold but did not affect AMPKα1 activity. STO-609 decreased ( P < 0.05) AMPKα2 activity induced by caffeine treatment and MC by 60% and 61% but did not affect AICAR-induced activity. Plasma membrane transport protein content of CD36 and glucose transporter 4 (GLUT4) increased ( P < 0.05) with caffeine, AICAR, and MC, and STO-609 prevented caffeine- and MC-induced increases in protein content. These results show the importance of Ca2+-dependent signaling via CaMKK activation in the regulation of substrate uptake and FA oxidation in contracting rat skeletal muscle and agree with the notion that CaMKK is an upstream kinase of AMPK in the regulation of substrate metabolism in skeletal muscle.
Identification of renal transporters involved in sulfate excretion in marine teleost fish
Authors: Kato Akira , Chang Min-Hwang , Kurita Yukihiro , Nakada Tsutomu , Ogoshi Maho , Nakazato Takeru , Doi Hiroyuki , Hirose Shigehisa , Romero Michael F.
Published: October 2009

Sulfate (SO42−) is the second most abundant anion in seawater (SW), and excretion of excess SO42−from ingested SW is essential for marine fish to survive. Marine teleosts excrete SO42−via the urine produced in the kidney. The SO42−transporter that secretes and concentrates SO42−in the urine has not previously been identified. Here, we have identified and characterized candidates for the long-sought transporters. Using sequences from the fugu database, we have cloned cDNA fragments of all transporters belonging to the Slc13 and Slc26 families from mefugu ( Takifugu obscurus ). We compared Slc13 and Slc26 mRNA expression in the kidney between freshwater (FW) and SW mefugu. Among 14 clones examined, the expression of a Slc26a6 paralog (mfSlc26a6A) was the most upregulated (30-fold) in the kidney of SW mefugu. Electrophysiological analyses of Xenopus oocytes expressing mfSlc26a6A, mfSlc26a6B, and mouse Slc26a6 (mSlc26a6) demonstrated that all transporters mediate electrogenic Cl−/SO42−, Cl−/oxalate2−, and Cl−/ nHCO3−exchanges and electroneutral Cl−/formate−exchange. Two-electrode voltage-clamp experiments demonstrated that the SO42−-elicited currents of mfSlc26a6A is quite large (∼35 μA at +60 mV) and 50- to 200-fold higher than those of mfSlc26a6B and mSlc26a6. Conversely, the currents elicited by oxalate and HCO3−are almost identical among mfSlc26a6A, mfSlc26a6B, and mSlc26a6. Kinetic analysis revealed that mfSlc26a6A has the highest SO42−affinity as well as capacity. Immunohistochemical analyses demonstrated that mfSlc26a6A localizes to the apical (brush-border) region of the proximal tubules. Together, these findings suggest that mfSlc26a6A is the most likely candidate for the major apical SO42−transporter that mediates SO42−secretion in the kidney of marine teleosts.
The role of aldosterone in mediating the dependence of angiotensin hypertension on IL-6
Authors: Sturgis LaShon C. , Cannon Joseph G. , Schreihofer Derek A. , Brands Michael W.
Published: October 2009

Knockout (KO) of IL-6 has been shown to attenuate ANG II hypertension, and mineralocorticoid receptors (MR) have been reported to contribute to the increase in IL-6 during acute ANG II infusion. This study determined whether that MR action is sustained with chronic ANG II infusion and whether it plays a role in mediating ANG II hypertension. ANG II infusion (90 ng/min) increased plasma IL-6 from 1.6 ± 0.6 to 22.7 ± 2.2 and 19.9 ± 3.2 pg/ml on days 7 and 14, respectively, and chronic MR blockade with spironolactone attenuated that only at day 7 (7.2 ± 2.2 pg/ml). ANG II increased MAP (19 h/day with telemetry) ∼40 mmHg, but in ANG II+spironolactone mice (25 or 50 mg·kg−1·day−1), mean arterial pressure (MAP) was not significantly different despite a tendency for lower pressure the first 6 days. To isolate further the mineralocorticoid link to IL-6 and blood pressure, DOCA-salt hypertension was induced in IL-6 KO and wild-type (WT) mice. Plasma IL-6 increased from 4.1 ± 1.7 to 34.5 ± 7.0 pg/ml by day 7 of DOCA treatment in the WT mice but was back to control levels by day 14. An IL-6 bioassay using the murine B9, B-cell hybridoma cell line demonstrated that plasma IL-6 measurements reflected actual IL-6 bioactivity. The hypertension was not different and virtually superimposable in WT vs. IL-6 KO mice, averaging 145 ± 2 and 144 ± 3 mmHg, respectively. Both experiments confirm chronic stimulation of IL-6 by mineralocorticoids but show that it is transient. In addition, IL-6 was not required for mineralocorticoid hypertension. This suggests that aldosterone contributes to the increase in plasma IL-6 in the early stage of ANG II hypertension but that the blood pressure actions of IL-6 in that model are linked most likely to ANG II rather than aldosterone.
Effect of whole body heat stress on peripheral vasoconstriction during leg dependency
Authors: Brothers R. Matthew , Wingo Jonathan E. , Hubing Kimberly A. , Del Coso Juan , Crandall Craig G.
Published: October 2009

The venoarteriolar response (VAR) increases vascular resistance upon increases in venous transmural pressure in cutaneous, subcutaneous, and muscle vascular beds. During orthostasis, it has been proposed that up to 45% of the increase in systemic vascular tone is due to VAR-related local mechanism(s). The objective of this project was to test the hypothesis that heat stress attenuates VAR-mediated cutaneous and whole leg vasoconstriction. During normothermic conditions, measurements of cutaneous blood flow (laser-Doppler flowmetry) and femoral artery blood flow (Doppler ultrasound) were obtained from both legs during supine and leg-dependent conditions. These measurements were repeated following a whole body heat stress (increase in internal temperature of 1.4 ± 0.2°C). Before leg dependency, cutaneous (CVC) and femoral vascular conductances (FVC) were significantly elevated in both legs during heat stress relative to normothermia ( P < 0.001). During leg dependency the absolute decrease in CVC was attenuated during heat stress ( P < 0.01) while the absolute decrease in FVC was unaffected ( P = 0.90). When CVC and FVC data were analyzed as a relative change from their respective baseline values, heat stress significantly attenuated the magnitude of vasoconstriction due to leg dependency in the cutaneous and femoral circulations ( P < 0.001 for both variables). These data suggest that an attenuated local vasoconstriction, evoked via the venoarteriolar response, may contribute to reduced blood pressure control and thus reduced orthostatic tolerance that occurs in heat-stressed individuals.
Laminar and Orientation-Dependent Characteristics of Spatial Nonlinearities: Implications for the Computational Architecture of Visual Cortex
Authors: Victor Jonathan D. , Mechler Ferenc , Ohiorhenuan Ifije , Schmid Anita M. , Purpura Keith P.
Published: October 2009

A full understanding of the computations performed in primary visual cortex is an important yet elusive goal. Receptive field models consisting of cascades of linear filters and static nonlinearities may be adequate to account for responses to simple stimuli such as gratings and random checkerboards, but their predictions of responses to complex stimuli such as natural scenes are only approximately correct. It is unclear whether these discrepancies are limited to quantitative inaccuracies that reflect well-recognized mechanisms such as response normalization, gain controls, and cross-orientation suppression or, alternatively, imply additional qualitative features of the underlying computations. To address this question, we examined responses of V1 and V2 neurons in the monkey and area 17 neurons in the cat to two-dimensional Hermite functions (TDHs). TDHs are intermediate in complexity between traditional analytic stimuli and natural scenes and have mathematical properties that facilitate their use to test candidate models. By exploiting these properties, along with the laminar organization of V1, we identify qualitative aspects of neural computations beyond those anticipated from the above-cited model framework. Specifically, we find that V1 neurons receive signals from orientation-selective mechanisms that are highly nonlinear: they are sensitive to phase correlations, not just spatial frequency content. That is, the behavior of V1 neurons departs from that of linear–nonlinear cascades with standard modulatory mechanisms in a qualitative manner: even relatively simple stimuli evoke responses that imply complex spatial nonlinearities. The presence of these findings in the input layers suggests that these nonlinearities act in a feedback fashion.
State-Dependent Performance of Optic-Flow Processing Interneurons
Authors: Longden Kit D. , Krapp Holger G.
Published: October 2009

Active locomotive states are metabolically expensive and require efficient sensory processing both to avoid wasteful movements and to cope with an extended bandwidth of sensory stimuli. This is particularly true for flying animals because flight, as opposed to walking or resting, imposes a steplike increase in metabolism for the precise execution and control of movements. Sensory processing itself carries a significant metabolic cost, but the principles governing the adjustment of sensory processing to different locomotor states are not well understood. We use the blowfly as a model system to study the impact on visual processing of a neuromodulator, octopamine, which is known to be involved in the regulation of flight physiology. We applied an octopamine agonist and recorded the directional motion responses of identified visual interneurons known to process self-motion–induced optic flow to directional motion stimuli. The neural response range of these neurons is increased and the response latency is reduced. We also found that, due to an elevated spontaneous spike rate, the cells' negative signaling range is increased. Meanwhile, the preferred self-motion parameters the cells encode were state independent. Our results indicate that in the blowfly energetically expensive sensory coding strategies, such as rapid, large responses, and high spontaneous spike activity could be adjusted by the neuromodulator octopamine, likely to save energy during quiet locomotor states.
Dynamics of Spatial Distortions Reveal Multiple Time Scales of Motion Adaptation
Authors: Roach Neil W. , McGraw Paul V.
Published: October 2009

Prolonged exposure to consistent visual motion can significantly alter the perceived direction and speed of subsequently viewed objects. These perceptual aftereffects have provided invaluable tools with which to study the mechanisms of motion adaptation and draw inferences about the properties of underlying neural populations. Behavioral studies of the time course of motion aftereffects typically reveal a gradual process of adaptation spanning a period of multiple seconds. In contrast, neurophysiological studies have documented multiple motion adaptation effects operating over similar, or substantially faster (i.e., sub-second) time scales. Here we investigated motion adaptation by measuring time-dependent changes in the ability of moving stimuli to distort the perceived position of briefly presented static objects. The temporal dynamics of these motion-induced spatial distortions reveal the operation of two dissociable mechanisms of motion adaptation with differing properties. The first is rapid (subsecond), acts to limit the distortions induced by continuing motion, but is not sufficient to produce an aftereffect once the motion signal disappears. The second gradually accumulates over a period of seconds, does not modulate the size of distortions produced by continuing motion, and produces repulsive aftereffects after motion offset. These results provide new psychophysical evidence for the operation of multiple mechanisms of motion adaptation operating over distinct time scales.
Protein Tyrosine Kinase Involvement in Learning-Produced Changes in Hermissenda Type B Photoreceptors
Authors: Jin Iksung , Huang Haojiang , Smith Benjamin , Farley Joseph
Published: October 2009

Learning-correlated changes in the excitability and photoresponses of Hermissenda 's ocular type B photoreceptors are mediated by reductions in two distinct K+currents, IAand IK-Ca. The suppression of these K+currents has been linked to conditioning-produced activation of protein kinase C (PKC). The question of whether PKC accounts completely for the changes in excitability and K+currents or whether other kinase(s) are involved has received little attention. In the present experiments, we asked whether protein tyrosine kinases (PTKs) might also contribute to conditioning-produced alterations in B cells. We found that the PTK inhibitors genistein and lavendustin A greatly reduced cumulative depolarization of type B cells, a short-term correlate of associative learning. This disruption occurred even when PKC activation had been either occluded by preexposure of type B cells to a phorbol ester or otherwise prevented by the pseudosubstrate inhibitor peptide PKC[19–31]. PTK inhibitors also increased the amplitude of the transient ( IA) and delayed ( IDelayed) components of voltage-dependent K+current that have previously been shown to be selectively reduced by conditioning and to contribute to cumulative depolarization. Genistein partially prevented the reduction of IAand IDelayeddue to in vitro conditioning and blocked the changes in their voltage dependencies. Ionophoresis of pervanadate ion, a potent inhibitor of protein tyrosine phosphatases, depolarized type B photoreceptors and occluded conditioning-produced cumulative depolarization. Pervanadate also suppressed IAand IDelayed, reduced their voltage dependence, and altered inactivation kinetics for IA, mimicking conditioning. Western blot analysis using a phosphotyrosine antibody indicated that conditioning increased the phosphotyrosine content of many proteins within the Hermissenda CNS. Collectively, our results suggest that in addition to PKC, one or more PTKs play an important role in conditioning-produced changes in type B cell excitability. PTKs and PKCs converge to effect reductions in B cell K+currents during conditioning, apparently through distinct biophysical mechanisms.
Visual-Manual Exploration and Posterior Parietal Cortex in Humans
Authors: Hinkley Leighton B. N. , Krubitzer Leah A. , Padberg Jeff , Disbrow Elizabeth A.
Published: October 2009

Areas of human posterior parietal cortex (PPC) specialized for processing sensorimotor information associated with visually locating an object, reaching to grasp, and manually exploring that object were examined using functional MRI. Cortical activation was observed in response to three tasks: 1) saccadic eye movements, 2) visually guided reaching to grasp, and 3) manual shape discrimination. During saccadic eye movements, cortical fields within the lateral and rostral superior parietal lobe (SPL) and the caudal SPL and parieto-occipital boundary were active. During visually guided reaching to grasp, regions of cortex within the postcentral sulcus (PoCS) and rostral intraparietal sulcus (IPS) were active, as well as the caudal SPL of the left hemisphere and the medial and caudal IPS of the right hemisphere. Cortical regions at the junction of the IPS and PoCS and an area in the medial SPL were active bilaterally during shape manipulation. Only a few regions were most active during a single motor behavior, whereas several areas were highly active during two or more tasks. Hemispheric asymmetries in activation patterns were observed during visually guided reaching to grasp. The gross areal organization of human PPC is likely similar to the pattern previously described in nonhuman primates, including multifunctional regions and asymmetric processing of some manual abilities.
Physiological Signaling Specificity by Protein Tyrosine Phosphatases
Authors: Soulsby Matthew , Bennett Anton M.
Published: October 2009

Protein tyrosine phosphatases (PTPs) are now recognized to be involved in a multitude of signaling events that control fundamental biological processes such as cell growth, differentiation, apoptosis, and cell movement. PTPs, which were initially thought to be less discriminating in their actions compared with their protein tyrosine kinase counterparts, are now known to regulate these various biological processes in a precise manner. This review will focus on the concept that PTPs exhibit remarkable signaling specificity through intrinsic differences between their PTP domains and through various modes of regulation that endows them with the capacity to promote unique physiological responses.
Potassium Ion Movement in the Inner Ear: Insights from Genetic Disease and Mouse Models
Authors: Zdebik Anselm A. , Wangemann Philine , Jentsch Thomas J.
Published: October 2009

Sensory transduction in the cochlea and vestibular labyrinth depends on fluid movements that deflect the hair bundles of mechanosensitive hair cells. Mechanosensitive transducer channels at the tip of the hair cell stereocilia allow K+ to flow into cells. This unusual process relies on ionic gradients unique to the inner ear. Linking genes to deafness in humans and mice has been instrumental in identifying the ion transport machinery important for hearing and balance. Morphological analysis is difficult in patients, but mouse models have helped to investigate phenotypes at different developmental time points. This review focuses on cellular ion transport mechanisms in the stria vascularis that generate the major electrochemical gradients for sensory transduction.
Role of Extracellular Adenosine in Acute Lung Injury
Authors: Eckle Tobias , Koeppen Michael , Eltzschig Holger K.
Published: October 2009

Acute lung injury (ALI) is a lung disease characterized by pulmonary edema and severe hypoxia. The past decade hosted a search for endogenous mechanisms controlling lung inflammation and pulmonary edema during ALI. As such, recent evidence indicates extracellular adenosine in orchestrating the resolution of pulmonary edema and inflammation during ALI.
Preliminary Feasibility Study of Benzo(a)Pyrene Oxidative Degradation by Fenton Treatment
Authors: Homem Vera , Dias Zélia , Santos Lúcia , Alves Arminda
Published: October 2009

Polycyclic aromatic hydrocarbons (PAHs) are considered priority compounds due to their toxic and carcinogenic nature. The concern about water contamination and the consequent human exposure has encouraged the development of new methods for PAHs removal. The purpose of this work was to study the feasibility of a degradation process of benzo(a)pyrene (BaP) in aqueous matrices by oxidation with Fenton reagent. A laboratory unit was designed to optimize the factors which may influence the process: pH (3.5 to 6.0), temperature (30 to70°C),H2O2(20 to 150 mgL-1),Fe2+concentration (2.75 to 5.50 mgL-1), and the initial concentration of the pollutant (10 to 100 μgL-1). The pH did not influence significantly the results in the range studied. An increase in temperature from 30 to70°Cimproved the removal efficiency from 90% to 100%. The same effect was observed for ferrous ion concentrations from 2.75 to 5.50 mgL-1(increase from 78% to 100% removal). TheH2O2concentration played a double role during the process: from 20 to 50 mgL-1an increase in the removal efficiency was achieved, but for higher concentrations (>50 mgL-1) the degradation is lower. This study proved that the degradation of benzo(a)pyrene by Fenton's reagent is a viable process.
Synthesis, Cytotoxic Activity, and DNA Binding Properties of Copper (II) Complexes with Hesperetin, Naringenin, and Apigenin
Authors: Tan Mingxiong , Zhu Jinchan , Pan Yingming , Chen Zhenfeng , Liang Hong , Liu Huagang , Wang Hengshan
Published: October 2009

Complexes of copper (II) with hesperetin, naringenin, and apigenin of general composition
(1–3) have been synthesized and characterized by elemental analysis, UV‐Vis, FT‐IR, ESI‐MS, and TG‐DTG thermal analysis. The free ligands and the metal complexes have been tested in vitro against human cancer cell lines hepatocellular carcinoma (HepG‐2), gastric carcinomas (SGC‐7901), and cervical carcinoma (HeLa). Complexes 1 and 3 were found to exhibit growth inhibition of SGC‐7901 and HepG2 cell lines with respect to the free ligands; the inhibitory rate of complex 1 is 43.2% and 43.8%, while complex 3 is 46% and 36%, respectively. The interactions of complex 1 and its ligand Hsp with calf thymus DNA were investigated by UV‐Vis, fluorescence, and CD spectra. Both complex 1 and Hsp were found to bind DNA in intercalation modes, and the binding affinity of complex 1 was stronger than that of free ligand.
Soliton and Periodic Wave Solutions to the OsmosisK(2, 2) Equation
Authors: Zhou Jiangbo , Tian Lixin , Fan Xinghua
Published: October 2009

Two types of traveling wave solutions to the osmosis K(2, 2) equation
are investigated. They are characterized by two parameters. The expresssions for
the soliton and periodic wave solutions are obtained.
The Value of Surgery for Retroperitoneal Sarcoma
Authors: Gholami Sepideh , Jacobs Charlotte D. , Kapp Daniel S. , Parast Layla M. , Norton Jeffrey A.
Published: October 2009

Introduction. Retroperitoneal sarcomas are uncommon large malignant tumors.Methods. Forty-one consecutive patients with localized retroperitoneal sarcoma were retrospectively studied.Results. Median age was 58 years (range 20–91 years). Median tumor size was 17.5 cm (range 4–41 cm). Only 2 tumors were <5 cm. Most were liposarcoma (44%) and high-grade (59%). 59% were stage 3 and the rest was stage 1. Median followup was 10 months (range 1–106 months). Thirty-eight patients had an initial complete resection; 15 (37%) developed recurrent sarcoma and 12 (80%) had a second complete resection. Patients with an initial complete resection had a 5-year survival of 46%. For all patients, tumor grade affected overall survival (). Complete surgical resection improved overall survival for high-grade tumors ().Conclusions. Tumor grade/stage and complete surgical resection for high-grade tumors are important prognostic variables. Radiation therapy or chemotherapy had no significant impact on overall or recurrence-free survival. Complete surgical resection is the treatment of choice for patients with initial and locally recurrent retroperitoneal sarcoma.
Synthesis and Characterization of Upconversion Fluorescent Yb3	+, Er3	+ Doped CsY	2	F7 Nano‐ and Microcrystals
Authors: Schäfer Helmut , Ptacek Pavel , Eickmeier Henning , Haase Markus
Published: October 2009

Cs Y2F7: 78%   Y3+, 20%   Yb3+, 2%   Er3+ nanocrystals with a mean diameter of approximately 8 nm were synthesized at   185°C in the high boiling organic solvent N‐(2‐hydroxyethyl)‐ethylenediamine (HEEDA) using ammonium fluoride, the rare earth chlorides and a solution of caesium alkoxide of N‐(2‐hydroxyethyl)‐ethylenediamine in HEEDA. In parallel with this approach, a microwave assisted synthesis was carried out which forms nanocrystals of the same material, about 50 nm in size, in aqueous solution at 200∘C/8 bar starting from ammonium fluoride, the rare earth chlorides, and caesium fluoride. In case of the nanocrystals, derived from the HEEDA synthesis, TEM images reveal that the particles are separated but have a broad size distribution. Also an occurred heat‐treatment of these nanocrystals (600∘C for 45 minutes) led to bulk material which shows highly efficient light emission upon continuous wave (CW) excitation at 978 nm. Besides the optical properties, the structure and the morphology of the three products were investigated by means of powder XRD and Rietveld method.