bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF Ti ON THE OPTICAL BAND GAP OF FERROELECTRIC BaTixO5-BASED BULK GLASS
Authors: AHMAD JAVED , ALAM SHER , YU JIANDING , ARAI YASUTOMO
Published: August 2009

Optical transmittance on ferroelectric BaTi x O 5 (x=1.7, 2, 2.1)-based glasses prepared recently by a containerless synthesis technique is measured at room temperature in the wavelength range 190–800 nm. A sharp decrease in the transmittance observed in the ultraviolet (UV) region, which shifts toward longer wavelength region on increasing x is associated with fundamental absorption edge. From the linear region of the absorption coefficient calculated from the transmittance spectrum the optical band gap of 3.41 eV is estimated for x=1.7, which decreases on increasing x. The Urbach energy increases on increasing x demonstrating an increase of structural disorder in the ferroelectric BaTi x O 5 glass on increasing Ti concentration.
EXACT BRIGHT SELF-SIMILAR SOLITARY WAVES IN AN EXPULSIVE PARABOLIC POTENTIAL
Authors: WANG FENGJIAO , YAN XIAOHONG , WANG DENGLONG , DING JIANWEN
Published: August 2009

Exact bright self-similar solitary waves are analytically derived in a cigar-shaped condensate with time-dependent atomic scattering length as(t) in an expulsive parabolic potential. The straightforward relation between the Gross–Pitaevskii equation and the standard nonlinear Schrödinger equation is presented for as(t)=a0exp (γt) at the growing or decaying coefficient γ=±|ωz|/ωtwith ωz(ω⊥) the axial (transverse) frequency. In the expulsive parabolic potential, in particular, it is found that the bright self-similar solitary wave is accelerated and set into motion due to the expulsive force. The results tally with the experimental observations by Khaykovich et al. [Science296 (2002) 1290].
ACOUSTIC PHONON TRANSPORT THROUGH A QUANTUM WAVEGUIDE WITH TWO PARTLY-OVERLAPPED STUBS
Authors: LI HONGJIAN , YAN SHUHUAN , ZHANG HAIYAN , XIE SUXIA , ZHOU XIN
Published: August 2009

By using the scattering matrix method, we investigate the effect of two partly-overlapped stubs in a quantum waveguide on acoustic phonon transport and thermal conductance at low temperature. We demonstrate that the transmission coefficient is of the quantum characteristic and shows obvious discrepancies for the different discontinuity structures. The number of the stop-frequency depends on the value of the stubs' heights and ballistic transport for the mode 0 is possible when the stress-free boundary conduction is used. In addition, the thermal conductance exhibits mode-splitting behavior and sensitively depends on the heights and widths of the two partly-overlapped stubs.
A STUDY ON STRAIN AFFECTING ELECTRONIC STRUCTURE OF WURTZITEZnOBY FIRST PRINCIPLES
Authors: SHI LI BIN , CHENG SHUANG , LI RONG BING , KANG LI , JIN JIAN WEI , LI MING BIAO , XU CUI YAN
Published: August 2009

Density of states and band structure of wurtzite ZnO are calculated by the CASTEP program based on density functional theory and plane-wave pseudopotential method. The calculations are carried out in axial and unaxial strains, respectively. The results of density of states in different strains show that the bottom of the conduction band is always dominated by Zn 4s, and the top of valence band is always dominated by O 2p. The variation of the band gap calculated from band structure is also discussed. In addition, p-d repulsion is used in investigating the variation of the top of the valence band in different strains and the results can be verified by electron density difference.
A STUDY OF THE GROUND STATE BEHAVIOR OF A TWO-ELECTRON QUANTUM RING
Authors: XIE WENFANG
Published: August 2009

We study a two-electron system of a quantum ring under the influence of a perpendicular homogeneous magnetic field. Calculations are made by using the method of numerical diagonalization of Hamiltonian matrix within the effective-mass approximation. A ground-state behavior (spin singlet–triplet transitions) as a function of the strength of a magnetic field is investigated. We find that the ring radius R0 and the ring width W are important for the singlet–triplet transition of the ground-state.
LOAD-STRENGTH INTERFERENCE FAILURE RATE MODEL
Authors: XIE LIYANG , WANG ZHENG
Published: August 2009

The variation of failure rate is interpreted in terms of the interaction mechanism between load and strength (product property). It is highlighted that the variation of product failure rate with service time is controlled by two types of failure rate variation trends. One is the decreasing trend dominated by load statistical characteristic, the other is the increasing trend dominated by strength degradation. Under the action of a stationary random load process, the statistical characteristics of load peaks leads to product failure rate decreasing with service time, provided that the product property does not degrade. The reason is simply that, a product will not fail to a impact of load not higher than those to which the product has successfully resisted, while the possibility that a higher impact (higher than all the preceding ones) appears in a unit time interval will decrease with the increase of operation experience. On the other hand, load history dependent product property deterioration leads to failure rate increasing continuously. From the viewpoint that failure is the reflection of load-strength interaction, this paper derives failure rate model for product subjected to random load sequence. As the foundation, discrete time parameter, i.e. number of load actions is used, "discrete failure rate" is defined, and it is clarified that the discrete failure rate at the nth load action is equivalent to the failure probability caused by the (n + 1)th load action, given that the product has survived to the foregoing n times of load actions. Based on the failure rate model, the effects of load uncertainty, component strength uncertainty, and strength degradation as well on failure rate are discussed.
EFFICACIOUS DESIGN REVIEW PROCESS INCLUDING ON-THE-JOB TRAINING IN FINDING MISUNDERSTAND ERRORS
Authors: OTSUKA YUICHI , SHIMIZU HIROKAZU , NOGUCHI HIROSHI
Published: August 2009

The latent problem in the design stage involves unnoticed problems or misunderstood causes of failures. The unnoticed problem can be visualized by the process of the System DRBFM (Design Review Based on Failure Mode) that takes into account the hierarchical structure of products. The misunderstood problems are also visualized by the question by a professional adviser in which involves his important aspects when considers the problems. Afterwards, the contents of the found problems are used to improve Attention in operation, which is the check list of questions, corresponding to the considered failures, that should be asked to designers in next case. The System DRBFM can be regarded as a proactive prevention system by professional adviser, design regulation and attention in operation. This paper proposes an additional function for the System DRBFM. That is an OJT (On-the-Job Training) tool that the professional adviser educates a designer who took misunderstood or unnoticed mistakes in order to timely acquire his lacked knowledge and experiences. To present the effectiveness of this concept, the case study of the design change in a hair drier is illustrated. The application can intelligibly demonstrate the effectiveness of the System DRBFM.
New phthalocyanines containing bulky electron rich substituents
Authors: Özçeşmeci İbrahim , Güney Orhan , Okur Ali İhsan , Gül Ahmet
Published: August 2009

Metal-free and metallophthalocyanines with four 9-anthroyl groups bound through ethylthio ester bridges on the periphery have been prepared. The new compounds were characterized by elemental analyses, 1 H NMR, IR, mass and UV-vis spectral data. The electronic spectra exhibit an intense π-π* transition of 9-anthroyl identity together with characteristic Q and B bands of the phthalocyanine core. Effect of metal ions on intensity of fluorescence spectra of phthalocyanine derivatives substituted with 9-anthroyl groups was investigated. The energy transfer to the phthalocyanine core and radiative decays of the 9-anthroyl emission and phthalocyanine core were examined.
Both alcohol and halogenated solvents soluble soft-metal sensor functional phthalocyanines: synthesis, electrochemistry, spectroelectrochemistry
Authors: Kandaz Mehmet , Yaraşir Meryem N. , Güney Tezcan , Koca Atıf
Published: August 2009

In this study, we report a novel both alcohol and haloganated solvent soluble selective ionophore functional ligand and its β-substituted 2(3),9(10),16(17),23(24)-tetrakis(1-hydroxyhexan-3-ylthio)-phthalocyanines, M { Pc [ S-CH ( CH 2 CH 2 CH 3)( CH 2 CH 2 OH )]4}, (Pc: Phthalocyanine) ( M = Zn , Cu , Co ), where -OH indicates peripheral functionality. Pcs exhibiting both hydrophobic and hydrophilic character were characterized spectroscopically (FT-IR, 1 H and 13 C NMR, MS (MALDI-TOF) and UV-vis), electrochemically and spectroelectrochemically. The complexes were soluble in both polar solvents, such as MeOH and EtOH, and non-polar solvents such as CHCl 3, CH 2 Cl 2, benzene, toluene, and even hexane. Absorption spectral changes of the functional MPcs during addition of AgI and PdII soft-metal ions are evaluated by monomer-oligomer and even polymer formations technique and monitored for in situ monitoring technique in the UV-vis spectroscopy. The binding process results in considerable blue-shift in the absorption spectra of MPcs . According to continuous variation method, the ligand:metal ratio was found ca. 1:1 and 1.5:1 for total concentration of 1.0 × 10-5 M and 7.5 × 10-5 M , respectively. Their electrochemical and spectroelectrochemical studies show that the complexes exhibited stable monoanionic M { Pc [ S-CH ( CH 2 CH 2 CH 3)( CH 2 CH 2 OH )]4}1-, dianionic M { Pc [ S-CH ( CH 2 CH 2 CH 3)( CH 2 CH 2 OH )]4}2- and monocationic M { Pc [ S-CH ( CH 2 CH 2 CH 3)( CH 2 CH 2 OH )]4}1+ species during reduction and oxidation processes.
Preparation of iron phthalocyanine complex bearing four tetraazamacrocycles as a precursor for oxidation catalyst with two catalytic sites
Authors: İşci Ümit , Gürek Ayşe Gül , Ahsen Vefa , Sorokin Alexander B.
Published: August 2009

The synthesis of the iron phthalocyanine bearing four fused tetraazamacrocycles starting from N,N',N″,N‴-tetrakis(p-tolylsulfonyl)triethylenetetraamine and 1,2-dibromo-4,5-bis(bromomethyl)benzene is reported. The exchange of protecting tosyl groups by acetyl groups was necessary to obtain iron phthalocyanine. The efficiency of iron phthalocyanine as oxidation catalyst was tested for the practically important oxidation of 2,3,6-trimethylphenol (TMP) at different reaction conditions.
Water-soluble phthalocyanines mediated photodynamic effect on mesothelioma cells
Authors: Saydan Nil , Durmuş Mahmut , Dizge Meltem G. , Yaman Hanifi , Gürek Ayşe G. , Antunes Edith , Nyokong Tebello , Ahsen Vefa
Published: August 2009

The new peripherally 2-mercaptopyridine tetrasubstituted zinc phthalocyanine (2) and its quaternized derivative (3) have been synthesized and characterized by elemental analysis, IR, 1 H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternized compound (3) shows excellent solubility in water, which makes it a potential photosensitizer for use in photodynamic therapy (PDT) of cancer. Fluorescence and singlet oxygen quantum yield measurements were conducted on 2-mercaptopyridine appended zinc phthalocyanines in dimethylsulphoxide (DMSO) for both the non-ionic (2) and quaternized (3) derivatives, and in aqueous media for the water-soluble complex 3. General trends are described for fluorescence and singlet oxygen quantum yields of these compounds. In this study, the cells were incubated with a novel water-soluble zinc phthalocyanine derivative (3) and thereafter the cells were illuminated using broad-band incoherent light source of various energy levels. Cytotoxicity of PDT on two pleural malign mesothelioma cell lines was determined by colorimetric proliferation assay. In addition, after PDT treatment, determination of activity matrix metalloproteinases (MMPs) were evaluated using gelatine zymography.
Synthesis, characterization and spectroscopic properties of new fluorescent 7,8-dihexyloxy-3-(4-oxyphenyl)coumarin substituted phthalocyanines
Authors: Çamur Meryem , Özkaya Ali Rıza , Bulut Mustafa
Published: August 2009

The synthesis of metal-free and metallophthalocyanines ( M = Zn , Co ) obtained from 7,8-dihexyloxy-3-[p-(3',4'-dicyanophenoxy)phenyl]coumarin are described. The newly prepared compounds have been characterized by elemental analysis, IR, NMR, mass and UV-vis spectral data. Their electronic absorption and fluorescence spectral properties are reported. Cyclic voltammetry of the compounds have also been studied. In situ spectroelectrochemistry of the Co(II) complex in THF and DCM is included to identify the difference in its redox behavior, as compared with other complexes.
Synthesis, photophysical and photochemical studies of novel liquid crystalline phthalocyanines
Authors: Ayhan M. Menaf , Durmuş Mahmut , Gürek Ayşe G.
Published: August 2009

Ni(II) and Zn(II) phthalocyanines carrying four or eight branched oligo(ethyleneoxy)-thia groups on peripheral positions have been synthesized from new phthalonitrile derivatives. The new compounds have been characterized by elemental analysis, IR, NMR, mass spectra and electronic spectroscopy. The aggregation behaviors of the phthalocyanine complexes were studied in different solvents and concentrations. General trends are described for photodegradation, singlet oxygen and fluorescence quantum yields, and fluorescence lifetimes of these compounds in dimethylsulfoxide (DMSO). The effects of the substitution on the photophysical and photochemical parameters of the nickel(II) (3a and 4a) and zinc(II) phthalocyanines (4b) are also reported. The octasubstituted zinc(II) complex (3b) is not stable for these measurements. Preliminary investigation of the photophysical and photochemical properties of phthalocyanine complexes are very useful for further PDT applications. The mesogenic properties of these new materials were studied by differential scanning calorimetry (DSC), optical polarized microscopy and X-ray investigations.
Mice lacking neurofibromin develop gastric hyperplasia
Authors: Lin Lu , Chen Jian , Richardson James A. , Parada Luis F.
Published: August 2009

Gastrointestinal (GI) neoplasms are among many manifestations of the genetic disease neurofibromatosis type 1 (NF1). However, the physiological and pathological functions of the Nf1 gene in the GI system have not been fully studied, possibly because of a lack of mouse models. In this study, we generated conditional knockout mice with Nf1 deficiency in the GI tract. These mice develop gastric epithelial hyperplasia and inflammation together with increased cell proliferation and apoptosis. The gastric phenotypes observed in these mutant mice seem to be the consequence of loss of Nf1 in gastric fibroblasts, resulting in paracrine hyperactivation of the ERK pathway in the gastric epithelium. These mice provide a useful model to study the pathogenesis of GI lesions in a subset of patients with NF1 and to investigate the role of the Nf1 gene in the development of GI neoplasms.
Effects of electrical stimulation on isolated rodent gastric smooth muscle cells evaluated via a joint computational simulation and experimental approach
Authors: Du P. , Li S. , O'Grady G. , Cheng L. K. , Pullan A. J. , Chen J. D. Z.
Published: August 2009

Gastric electrical stimulation (GES) involves the delivery of electrical impulses to the stomach for therapeutic purposes. New GES protocols are needed that are optimized for improved motility outcomes and energy efficiency. In this study, a biophysically based smooth muscle cell (SMC) model was modified on the basis of experimental data and employed in conjunction with experimental studies to define the effects of a large range of GES protocols on individual SMCs. For the validation studies, rat gastric SMCs were isolated and subjected to patch-clamp analysis during stimulation. Experimental results were in satisfactory agreement with simulation results. The results define the effects of a wide range of GES parameters (pulse width, amplitude, and pulse-train frequency) on isolated SMCs. The minimum pulse width required to invoke a supramechanical threshold response from SMCs (defined at −30 mV) was 65 ms (at 250-pA amplitude). The minimum amplitude required to invoke this threshold was 75 pA (at 1,000-ms pulse width). The amplitude of the invoked response beyond this threshold was proportional to the stimulation amplitude. A high-frequency train of stimuli (40 Hz; 10 ms, 150 pA) could invoke and maintain the SMC plateau phase while requiring 60% less power and accruing ∼30% less intracellular Ca2+concentration during the plateau phase than a comparable single-pulse protocol could in a demonstrated example. Validated computational simulations are an effective strategy for efficiently identifying effective minimum-energy GES protocols, and pulse-train protocols may also help to reduce the power consumption of future GES devices.
Vasoactive intestinal peptide ameliorates intestinal barrier disruption associated withCitrobacter rodentium-induced colitis
Authors: Conlin V. S. , Wu X. , Nguyen C. , Dai C. , Vallance B. A. , Buchan A. M. J. , Boyer L. , Jacobson K.
Published: August 2009

Attaching and effacing bacterial pathogens attach to the apical surface of epithelial cells and disrupt epithelial barrier function, increasing permeability and allowing luminal contents access to the underlying milieu. Previous in vitro studies demonstrated that the neuropeptide vasoactive intestinal peptide (VIP) regulates epithelial paracellular permeability, and the high concentrations and close proximity of VIP-containing nerve fibers to intestinal epithelial cells would support such a function in vivo. The aim of this study was to examine whether VIP treatment modulated Citrobacter rodentium-induced disruption of intestinal barrier integrity and to identify potential mechanisms of action. Administration of VIP had no effect on bacterial attachment although histopathological scoring demonstrated a VIP-induced amelioration of colitis-induced epithelial damage compared with controls. VIP treatment prevented the infection-induced increase in mannitol flux a measure of paracellular permeability, resulting in levels similar to control mice, and immunohistochemical studies demonstrated that VIP prevented the translocation of tight junction proteins: zonula occludens-1, occludin, and claudin-3. Enteropathogenic Escherichia coli (EPEC) infection of Caco-2 monolayers confirmed a protective role for VIP on epithelial barrier function. VIP prevented EPEC-induced increase in long myosin light chain kinase (MLCK) expression and myosin light chain phosphorylation (p-MLC). Furthermore, MLCK inhibition significantly attenuated bacterial-induced epithelial damage both in vivo and in vitro. In conclusion, our results indicate that VIP protects the colonic epithelial barrier by minimizing bacterial-induced redistribution of tight junction proteins in part through actions on MLCK and MLC phosphorylation.
A simple method for assessing the energy cost of running during incremental tests
Authors: di Prampero Pietro Enrico , Salvadego Desy , Fusi Simonetta , Grassi Bruno
Published: August 2009

The energy cost of running (Cr) is classically determined from steady-state oxygen consumption (V̇o2) at constant speed, divided by running speed. In the present study, Cr was determined during incremental treadmill tests in the course of the assessment of V̇o2maxand related parameters as follows. Assume that the running speed is increased by a constant amount (Δv) at regular short intervals (T) and that, during each intensity transient below the gas exchange threshold, V̇o2increases exponentially, without time delay, toward the steady state. If V̇o2is averaged over homologous times within each speed step, neglecting the initial 10 s, the V̇o2difference between corresponding time values becomes constant and equal to the difference between the appropriate steady states. Thus Cr was obtained from the ratio of the difference between the V̇o2averages for any two homologous times, within subsequent periods, to the corresponding speed difference. Since in aerobic conditions, Cr on the treadmill is independent of the speed, and since Δv and T were constant, the relationship between V̇o2and speed is described by straight lines, where the slope yields Cr above resting. This was indeed experimentally observed, the slopes of the linear regressions ( R2range: 0.78 to 0.97 n = 9 to 16) within the three time windows being essentially equal. In six subjects, the grand-average of Cr amounted to 0.177 ± 0.011 ml O2/(kg·m) [3.70 ± 0.23 J/(kg·m)]. This value is essentially equal to that obtained for the same subjects by applying the “classical” procedure [0.177 ± 0.015 ml O2/(kg·m); 3.70 ± 0.31 J/(kg·m)], so confirming the validity of the incremental approach for assessing the energy cost of treadmill running.
Caspase and calpain activation both contribute to sepsis-induced diaphragmatic weakness
Authors: Supinski G. S. , Wang W. , Callahan L. A.
Published: August 2009

The cecal ligation perforation (CLP) model of sepsis is known to induce severe diaphragm dysfunction, but the cellular mechanisms by which this occurs remain unknown. We hypothesized that CLP induces diaphragm caspase-3 and calpain activation, and that these two enzymes act at the level of the contractile proteins to reduce muscle force generation. Rats ( n = 4/group) were subjected to 1) sham surgery plus saline (intraperitoneal); 2) CLP; 3) CLP plus administration of calpain inhibitor peptide III (12 mg/kg ip); or 4) CLP plus administration of a caspase inhibitor, zVAD-fmk (3 mg/kg). At 24 h, diaphragms were removed, and the following were determined: 1) calpain and caspase-3 activities by fluorogenic assay; 2) caspase-3 and calpain I protein levels; 3) the intact diaphragm force-frequency relationship; and 4) the force generated by contractile proteins of single, permeabilized diaphragm fibers in response to exogenous calcium. CLP significantly increased diaphragm calpain activity ( P < 0.02), caspase-3 activity ( P < 0.02), active calpain I protein levels ( P < 0.02), and active caspase-3 protein ( P < 0.02). CLP also reduced the force generated by intact diaphragm muscle ( P < 0.001) and the force generated by single-fiber contractile proteins ( P < 0.001). Administration of either calpain inhibitor III or zVAD-fmk markedly improved force generation of both intact diaphragm muscle ( P < 0.01) and single-fiber contractile proteins ( P < 0.001). CLP induces significant reductions in diaphragm contractile protein force-generating capacity. This force reduction is mediated by the combined effects of activated caspase and calpain. Inhibition of these pathways may prevent diaphragm weakness in infected patients.
Combined effects of fatigue and eccentric damage on muscle power
Authors: Choi Seung Jun , Widrick Jeffrey J.
Published: August 2009

Many physical activities can induce both transient and long-lasting muscle dysfunction. The separate and interactive effects of short-term fatigue and long-lasting contraction-induced damage were evaluated in an in vitro mouse soleus preparation (35°C) using the work loop technique. Repetitive fatiguing work loops reduced positive work (work produced by the muscle), increased negative work (work required to reextend the muscle), and reduced cyclical power (net work/time) immediately after treatment. These changes were readily reversible. The fatigue treatment had no long-term effects on optimal muscle length ( Lo) and isometric force (Po). High strain lengthening work loops, where the muscle contracted eccentrically, resulted in both immediate and long-lasting positive work, power, and Podeficits as well as a shift in Loto longer lengths. When the treatments were combined, i.e., fatigued muscles subjected to eccentric activity, the immediate power deficit exceeded the sum of the power deficits noted for the other two treatments. Much of this effect was due to an exaggerated rise in negative work. However, in the long term, power and Podeficits and the shift in Lowere reduced compared with the damage-only treatment. These results show that 1) the immediate effects of combined fatigue and damage on cyclical power are synergistic, in large part because of a reduced ability of the muscle to relax; and 2) fatigued muscles are less susceptible to long-term contraction-induced dysfunction. Fatigue may protect against long-term damage by reducing the probability that sarcomeres are lengthened beyond myofilament overlap.
Acute hypoxia impairs dynamic cerebral autoregulation: results from two independent techniques
Authors: Subudhi Andrew W. , Panerai Ronney B. , Roach Robert C.
Published: August 2009

We investigated the effect of acute hypoxia (AH) on dynamic cerebral autoregulation (CA) using two independent assessment techniques to clarify previous, conflicting reports. Twelve healthy volunteers (6 men, 6 women) performed six classic leg cuff tests, three breathing normoxic (FiO2= 0.21) and three breathing hypoxic (FiO2= 0.12) gas, using a single blinded, Latin squares design with 5-min washout between trials. Continuous measurements of middle cerebral artery blood flow velocity (CBFv; DWL MultiDop X2) and radial artery blood pressure (ABP; Colin 7000) were recorded in the supine position during a single experimental session. Autoregulation index (ARI) scores were calculated using the model of Tiecks et al. (Tiecks FP, Lam AM, Aaslid R, Newell DW. Stroke 26: 1014–1019, 1995) from ABP and CBFv changes following rapid cuff deflation (cuff ARI) and from ABP to CBFv transfer function, impulse, and step responses (TFA ARI) obtained during a 4-min period prior to cuff inflation. A new measure of %CBFv recovery 4 s after peak impulse was also derived from TFA. AH reduced cuff ARI (5.65 ± 0.70 to 5.01 ± 0.96, P = 0.04), TFA ARI (4.37 ± 0.76 to 3.73 ± 0.71, P = 0.04), and %Recovery (62.2 ± 10.9% to 50.8 ± 9.9%, P = 0.03). Slight differences between TFA and cuff ARI values may be attributed to heightened sympathetic activity during cuff tests as well as differential sensitivity to low- and high-frequency components of CA. Together, results provide consistent evidence that CA is impaired with AH. In addition, these findings demonstrate the potential utility of TFA ARI and %Recovery scores for future CA investigations.
Adenosine receptor antagonist and augmented vasodilation during hypoxic exercise
Authors: Casey Darren P. , Madery Brandon D. , Pike Tasha L. , Eisenach John H. , Dietz Niki M. , Joyner Michael J. , Wilkins Brad W.
Published: August 2009

We tested the hypothesis that adenosine contributes to augmented skeletal muscle vasodilation during hypoxic exercise. In separate protocols, subjects performed incremental rhythmic forearm exercise (10% and 20% of maximum) during normoxia and normocapnic hypoxia (80% arterial O2saturation). In protocol 1 ( n = 8), subjects received an intra-arterial administration of saline (control) and aminophylline (adenosine receptor antagonist). In protocol 2 ( n = 10), subjects received intra-arterial phentolamine (α-adrenoceptor antagonist) and combined phentolamine and aminophylline administration. Forearm vascular conductance (FVC; in ml·min−1·100 mmHg−1) was calculated from forearm blood flow (in ml/min) and blood pressure (in mmHg). In protocol 1, the change in FVC (ΔFVC; change from normoxic baseline) during hypoxic exercise with saline was 172 ± 29 and 314 ± 34 ml·min−1·100 mmHg−1(10% and 20%, respectively). Aminophylline administration did not affect ΔFVC during hypoxic exercise at 10% (190 ± 29 ml·min−1·100 mmHg−1, P = 0.4) or 20% (287 ± 48 ml·min−1·100 mmHg−1, P = 0.3). In protocol 2, ΔFVC due to hypoxic exercise with phentolamine infusion was 313 ± 30 and 453 ± 41 ml·min−1·100 mmHg−1(10% and 20% respectively). ΔFVC was similar at 10% (352 ± 39 ml·min−1·100 mmHg−1, P = 0.8) and 20% (528 ± 45 ml·min−1·100 mmHg−1, P = 0.2) hypoxic exercise with combined phentolamine and aminophylline. In contrast, ΔFVC to exogenous adenosine was reduced by aminophylline administration in both protocols ( P < 0.05 for both). These observations suggest that adenosine receptor activation is not obligatory for the augmented hyperemia during hypoxic exercise in humans.
Ketorolac alters blood flow during normothermia but not during hyperthermia in middle-aged human skin
Authors: Holowatz Lacy A. , Jennings John D. , Lang James A. , Kenney W. Larry
Published: August 2009

In young healthy humans full expression of reflex cutaneous vasodilation is dependent on cyclooxygenase (COX)- and nitric oxide synthase (NOS)-dependent mechanisms. Chronic low-dose aspirin therapy attenuates reflex cutaneous vasodilation potentially through both platelet and vascular COX-dependent mechanisms. We hypothesized the contribution of COX-dependent vasodilators to reflex cutaneous vasodilation during localized acute COX inhibition would be attenuated in healthy middle-aged humans due to a shift toward COX-dependent vasoconstrictors. Four microdialysis fibers were placed in forearm skin of 13 middle-aged (53 ± 2 yr) normotensive healthy humans, serving as control (Ringer), COX-inhibited (10 mM ketorolac), NOS-inhibited (10 mM NG-nitro-l-arginine methyl ester), and combined NOS- and COX-inhibited sites. Red blood cell flux was measured over each site by laser-Doppler flowmetry as reflex vasodilation was induced by increasing oral temperature (Tor) 1.0°C using a water-perfused suit. Cutaneous vascular conductance was calculated (CVC = flux/mean arterial pressure) and normalized to maximal CVC (CVCmax; 28 mM sodium nitroprusside). CVCmax was not affected by localized microdialysis drug treatment ( P > 0.05). Localized COX inhibition increased baseline (18 ± 3%CVCmax; P < 0.001) compared with control (9 ± 1%CVCmax), NOS-inhibited (7 ± 1%CVCmax), and combined sites (10 ± 1%CVCmax). %CVCmax in the COX-inhibited site remained greater than the control site with ΔTor ≤ 0.3°C; however, there was no difference between these sites with ΔTor ≥ 0.4°C. NOS inhibition and combined COX and NOS inhibition attenuated reflex vasodilation compared with control ( P < 0.001), but there was no difference between these sites. Localized COX inhibition with ketorolac significantly augments baseline CVC but does not alter the subsequent skin blood flow response to hyperthermia, suggesting a limited role for COX-derived vasodilator prostanoids in reflex cutaneous vasodilation and a shift toward COX-derived vasoconstrictors in middle-aged human skin.
Protein Expression in Vascular Endothelial Cells Obtained from Human Peripheral Arteries and Veins
Authors: Silver Annemarie E. , Christou Demetra D. , Donato Anthony J. , Beske Stacy D. , Moreau Kerrie L. , Magerko Katherine A. , Seals Douglas R.
Published: August 2009

Studying molecular mechanisms of vascular endothelial function in humans is difficult in part because of limited access to arteries. Access to peripheral veins is more practical. We determined if differences in protein expression of endothelial cells (EC) collected from a peripheral artery are reflected in measurements made on EC obtained from peripheral veins. EC were collected from the brachial artery and an antecubital vein of 106 healthy adults (60 men and 46 women, age 18–77 years). Quantitative immunofluorescence was used to measure protein expression of endothelial nitric oxide synthase (eNOS), Ser-1177 phosphorylated eNOS, manganese superoxide dismutase, nitrotyrosine, xanthine oxidase and nuclear factor-κB p65. Protein expression in EC obtained from brachial artery and antecubital vein sampling was moderately to strongly related (r = 0.59–0.81, all p < 0.0001, mean r = 0.70). Moreover, differences between subgroups in the lowest and highest tertiles of protein expression in EC obtained from arterial samples were consistently reflected in EC obtained from venous collections. These findings indicate that interindividual and group differences in expression of several proteins involved in nitric oxide production, oxidant production, antioxidant defense and inflammatory signaling in EC obtained from brachial artery sampling are consistently reflected in EC obtained from venous samples. Thus, EC collected from peripheral veins may provide a useful surrogate for EC obtained from arteries for measurements of EC protein expression in humans.
The PDE1A-PKCα Signaling Pathway Is Involved in the Upregulation of α-Smooth Muscle Actin by TGF-β1 in Adventitial Fibroblasts
Authors: Zhou Hai-Yan , Chen Wen-Dong , Zhu Ding-Liang , Wu Ling-Yun , Zhang Jia , Han Wei-Qing , Li Jian-Dong , Yan Chen , Gao Ping-Jin
Published: August 2009

Background: Increasing evidence has suggested that differentiation of adventitial fibroblasts (AFs) to myofibroblasts plays an important role in arterial remodeling. The molecular mechanisms by which myofibroblast formation is regulated still remain largely unknown. This study aimed to evaluate the role of cyclic nucleotide phosphodiesterase 1A (PDE1A) in the formation of adventitial myofibroblasts induced by transforming growth factor (TGF)-β1. Methods and Results: AFs were cultured by the explant method. Western blot and immunocytochemistry were applied for α-smooth muscle actin (SMA) or protein kinase C (PKC) α protein analysis. Results showed that TGF-β1 upregulated PDE1A protein expression in rat aortic AFs and pharmacological inhibition of PDE1A blocked TGF-β1-induced α-SMA expression, a marker of myofibroblast formation, suggesting that the upregulation of PDE1A may mediate TGF-β1-induced AF transformation. Moreover, calphostin C (a PKC inhibitor) inhibited TGF-β1-induced α-SMA expression, whereas phorbol-12-myristate-13-acetate (a PKC activator) induced it. Finally, the upregulation of PKCα expression by TGF-β1 was also inhibited by PDE1A inhibition. Conclusions: Taken together, our data suggest that TGFβ1 induces α-SMA expression and myofibroblast formation via a PDE1A-PKCα-dependent mechanism. Our study thus unveils a novel signaling mechanism underlying TGF-β1-induced adventitial myofibroblast formation.
Endothelial ETB Limits Vascular Remodelling and Development of Pulmonary Hypertension during Hypoxia
Authors: Kelland N.F. , Bagnall A.J. , Morecroft I. , Gulliver-Sloan F.H. , Dempsie Y. , Nilsen M. , Yanagisawa M. , MacLean M.R. , Kotelevtsev Y.V. , Webb D.J.
Published: August 2009

Background: We hypothesised that the potential protective effects of endothelial ETB are important in limiting pulmonary vascular muscularisation, vasoconstriction and the development of pulmonary arterial hypertension in response to hypoxia. Methods: EC-specific ETB knockout mice (EC ETB–/–) and control mice (ETBf/f) were subjected to hypobaric hypoxic (10% FiO2) or normoxic conditions for 14 days before assessment of right ventricular pressure and pulmonary vascular morphology and function. Results: During normoxia, no difference in right ventricular pressure was detected between EC ETB–/– (23.7 ± 1.7 mm Hg) and ETBf/f mice (20.2 ± 1.5 mm Hg). Hypoxia induced an exaggerated increase in right ventricular pressure in EC ETB–/– mice (34.4 ± 1.2 mm Hg vs. 24.6 ± 1.4 mm Hg), accompanied by an increase in right ventricular mass. No effect was observed in ETBf/f mice. Endothelin-1 constricted pulmonary arteries from both groups, although maximum response was similar irrespective of inspired oxygen or genotype. Hypoxia increased the percentage of muscularised vessels in both groups of mice, but the percentage increase was significantly greater in EC ETB–/– mice. Conclusions: The potential protective effects of endothelial ETB are important in limiting pulmonary vascular muscularisation and the development of pulmonary arterial hypertension in response to hypoxia.
Growth-Dependent Changes in the Contribution of Carbon Monoxide to Arteriolar Function
Authors: Samora Julie Balch , Goodwill Adam G. , Frisbee Jefferson C. , Boegehold Matthew A.
Published: August 2009

Background/Aims: Endothelium-dependent dilation of skeletal muscle arterioles is mediated by unknown factors in very young rats. We assessed the possible contribution of carbon monoxide (CO) to this dilation and to dilation in older animals. Methods: The effects of de-endothelialization or various pharmacological inhibitors on responses to CO or endothelium-dependent dilators were studied in gracilis muscle arterioles from rats at 3–4 weeks (‘weanlings’) and 6–7 weeks (‘juveniles’). Results: Exogenous CO constricted, rather than dilated, arterioles from both age groups. This constriction was reduced by endothelial removal or NOS inhibition in juvenile, but not weanling, arterioles. In contrast, this constriction was abolished by K+ channel inhibition in weanling, but not juvenile, arterioles. The heme precursor δ-aminolevulinic acid constricted juvenile arterioles but did not affect weanling arterioles. The heme oxygenase inhibitor chromium (III) mesoporphyrin IX abolished the endothelium-dependent dilation of juvenile arterioles to simvastatin, and reduced ACh- and simvastatin-induced dilations of weanling arterioles. Conclusion: These findings suggest that relatively high concentrations of exogenous CO can cause constriction by inhibiting endothelium-derived NO in juvenile arterioles and inhibiting K+ channels in weanling arterioles. Endogenous CO produced at lower concentrations can contribute to endothelium-dependent dilation in both age groups.
Vascular Cell Kinetics in Response to Intimal Injury ex vivo
Authors: Tigerstedt Nina-Maria , Savolainen-Peltonen Hanna , Lehti Satu , Hayry Pekka
Published: August 2009

Background: Recent studies indicate that the smooth muscle-like cells contributing to neointimal hyperplasia after vascular injury derive from circulating precursor cells. Here, we define the time course of precursor cell influx, the roles of separate vascular layers, and the relative role of migration versus proliferation to intimal hyperplasia. Methods and Results: After rat aortic denudation injury the neointimal cell number increased several 100-fold between days 4 and 28, preceded by a 5-fold increase in the number of adventitial cells and a 4-fold increase in the number of adventitial microvessels. The influx, migration, and maturation of neointimal cells were quantitated by culturing whole vessel explants at different time points after injury. Explant outgrowth increased 14-fold, and cell migration 3.5-fold on days 2–14 after injury. Cell proliferation increased less than 2-fold. The frequency of precursors to outgrowing cells, determined using limiting dilution analysis, increased 8-fold between days 2 and 4 after injury. Many outgrowing cells displayed characteristics of undifferentiated cells. Conclusions: Adventitial activation precedes development of the neointima, and precursor cell influx occurs on days 2–14 after injury. Cell migration, more than proliferation, contributes to fibrointimal dysplasia. These findings underline the importance of early therapeutic intervention with antimigratory compounds to prevent neointimal hyperplasia.
Prolactin in Ovarian Follicular Fluid Stimulates Endothelial Cell Proliferation
Authors: Castilla Alejandra , García Celina , Cruz-Soto Martha , Martínez de la Escalera Gonzalo , Thebault Stéphanie , Clapp Carmen
Published: August 2009

Angiogenesis is essential for the growth and maturation of the ovarian follicle and its transition into the corpus luteum. In addition to the main proangiogenic factors, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), follicular fluid (FF) contains the hormone prolactin (PRL), which is known to promote angiogenesis in vivo. Here, we show that FF from large follicles, which contains twice the PRL level of FF from small follicles, stimulates endothelial cell proliferation to a greater extent than the latter, and that immunoneutralization of PRL prevents FF from stimulating endothelial cell proliferation. Notably, the FF increases the expression of the short and long PRL receptor isoforms in endothelial cells, and a purified PRL standard stimulates endothelial cell proliferation but only after the cells have been pretreated with FF. However, purified PRL activates the JAK2/STAT3 pathway in endothelial cells in the absence of pretreatment with FF. In summary, PRL present in the FF stimulates the proliferation of endothelial cells. This effect likely involves the upregulation of the short and long PRL receptor isoforms and is independent of PRL-induced JAK2/STAT3 signaling.
The Basement Membrane of Intramyocardial Capillaries Is Thickened in Patients with Acute Myocardial Infarction
Authors: Begieneman Mark P.V. , van de Goot Frank R.W. , Krijnen Paul A.J. , Fritz Jan , Paulus Walter J. , Spreeuwenberg Marieke D. , van Hinsbergh Victor W.M. , Niessen Hans W.M.
Published: August 2009

Background: Atherosclerotic epicardial coronary arteries are a major cause of acute myocardial infarction (AMI). Recently, we found that intramyocardial capillaries may also play a role in AMI induction. We have now evaluated intramyocardial capillaries using ultrastructural analysis in AMI patients. Methods: 43 AMI patients (with AMI in the left ventricle) and 27 controls. No patient included in either group had diabetes mellitus. Basement membrane (BM) thickness of intramyocardial capillaries was determined using electron microscopy. BM thickness was also studied in a rat AMI model. Results: BM thickness in the left ventricle of AMI patients was significantly higher than in controls (102 ± 9 vs. 77 ± 4 nm; p = 0.016). This increase was not found in the right ventricle. In AMI patients, BM thickness was already increased in recent infarcts and did not increase further with infarct age. No correlation was found between BM thickness and the amount of stenosis or atherosclerotic plaque stability of epicardial coronary arteries. In addition, BM thickness did not differ between control rats and AMI rats. Conclusions: These results suggest that BM thickening constitutes significant changes in the intramyocardial capillaries in patients that develop AMI. Also these changes are likely to occur prior to the induction of AMI.
Contraception and Induced Abortions for Women of Reproductive Age Married in Recent Years in Rural Areas of Shandong, China
Authors: Li H. , Li D.Q. , Li H.Q. , Diao Y.T.
Published: August 2009

Background: In 2001, the Chinese Government published the Population and Family Planning Law which gave citizens the right to know the facts about, and to choose, methods of birth control. Since then, the percentage use of different contraceptive methods has changed. More and more women have been using male condoms for birth control, which has resulted in an increasing prevalence of induced abortions of unintended pregnancies in recent years. Objective: To investigate the relationship between choice of contraception methods and rates of induced abortion in the rural areas of Shandong. Materials and Methods: A questionnaire-based survey on contraceptive methods and abortions in women of reproductive age who married between January 1, 2002, and August 31, 2005, was carried out in 8 sampling communities of rural areas in Shandong Province.Results: 7,159 of 8,520 women of childbearing age took part in the survey, which gave a response rate of 84.0%. The accumulative abortion rate was 2.39% for intrauterine device (IUD) use and 5.46% for male condom use during the period of survey. A longer duration of marriage and a longer time of male condom use increased the rate of induced abortions, while longer periods of IUD use decreased the rate of induced abortions. Conclusion: The results indicated that an integrated program for family planning, especially one that better educates condom users, must be initiated in the rural areas of Shandong Province, China.
Left-Ventricular Power-to-Mass Ratio at Peak Exercise Predicts Mortality, Heart Failure, and Cardiovascular Events in Patients with Stable Coronary Artery Disease: Data from the Heart and Soul Study
Authors: Farzaneh-Far Ramin , Na Beeya , Whooley Mary A. , Schiller Nelson B.
Published: August 2009

Background: Quantitative stress echocardiography enables calculation of left-ventricular power-to-mass ratio (LVPMR) at peak exercise, a novel measure of cardiac performance per unit mass of myocardial tissue. We hypothesized that LVPMR at peak exercise provides prognostic information beyond established echocardiographic indices such as left-ventricular ejection fraction (LVEF) and left-ventricular mass index (LVMI). Methods: LVPMR (watts/kilogram) at peak exercise was defined as (k × heart rate × mean arterial pressure × stroke volume)/LV mass. We measured LVPMR in 918 adults with stable ambulatory coronary artery disease recruited for the Heart and Soul Study. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for all-cause mortality, cardiovascular death, nonfatal myocardial infarction, heart failure hospitalization, and combined adverse cardiovascular events. Multivariate adjustments were made for established risk factors including LVEF and LVMI. The prognostic value of LVPMR was also compared with established exercise parameters using receiver-operating characteristic curve analysis. Results: Compared with patients in the highest LVPMR quartile, those in the lowest quartile were at increased risk of all-cause mortality (adjusted HR 1.9; 95% CI 1.1–3.3), heart failure hospitalization (adjusted HR 2.9; 95% CI 1.2–6.9), and combined adverse cardiovascular events (adjusted HR 1.9; 95% CI 1.1–3.4). In comparison with the rate-pressure product and the Duke treadmill score, LVPMR did not add significant prognostic value (p > 0.1 for c-statistic comparisons). Conclusions: In patients with stable ambulatory coronary artery disease, LVPMR at peak exercise predicts mortality, heart failure hospitalization, and adverse cardiovascular events. However, LVPMR does not add significant prognostic information beyond established exercise test parameters.
Executive Dysfunction in Patients with Obstructive Sleep Apnea Syndrome
Authors: Saunamäki Tiia , Himanen Sari-Leena , Polo Olli , Jehkonen Mervi
Published: August 2009

Aims: To clarify whether patients with obstructive sleep apnea syndrome (OSAS) have executive dysfunction, to identify the domains of executive function affected and to establish the severity of any dysfunction. Methods: A full-night polysomnography and a comprehensive neuropsychological assessment focusing on executive functions were conducted on 40 newly diagnosed OSAS patients and 20 healthy controls. The severity of dysfunction was analyzed using norm-referenced data. Results: All patients and controls were men. The groups did not differ statistically significantly in terms of age, education or intelligence quotient. Patients showed poorer performance than controls on the copy of the Rey-Osterrieth Complex Figure test, the Block Design, the Trails B of the Trail Making Test and the Intra-Extra Dimensional Set Shifting test. Based on the normative data, most OSAS patients performed at a normal level, but a few patients had either mild dysfunction (2.5–12.5%) or moderate to severe dysfunction (5–15%). Conclusions: OSAS patients have lower set-shifting and analysis/synthesis performance than healthy controls. According to the normative data, most patients in the present study had normal performance, but there were also a few patients with more serious deficits.