Search

A search for exotic dark matter (DM) in the sub-GeV mass range has been conducted using 205 kg$\cdot$day data taken from a p-type point contact germanium detector of CDEX-10 experiment at China Jinping underground laboratory. New low-mass dark matter searching channels, neutral current fermionic DM absorption ($\chi+A\rightarrow \nu+A$) and DM-nucleus 3$\rightarrow$2 scattering ($\chi+\chi+A\rightarrow \phi+A$), have been analyzed with an energy threshold of 160 eVee. No significant signal was found. Thus new limits on the DM-nucleon interaction cross section are set for both models at sub-GeV DM mass region. A cross section limit for the fermionic DM absorption is set to be $\rm 2.5\times 10^{-46} cm^2$(90\% C.L.) at DM mass of 10 MeV/c$^2$. For the DM-nucleus 3$\rightarrow$2 scattering scenario, limits are extended to DM mass of 5 MeV/c$^2$ and 14 MeV/c$^2$ for the massless dark photon and bound DM final state, respectively., Comment: 5 pages, 7 figures

We report constraints on the dark photon effective kinetic mixing parameter (${\kappa}$) with data taken from two ${p}$-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90\% confidence level upper limits on ${\kappa}$ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (${m_V}$) from 10 to 300 eV/${c^2}$ in direct detection experiments. Considering dark photon as the cosmological dark matter, limits at 90\% confidence level with ${m_V}$ from 0.1 to 4.0 keV/${c^2}$ are set from 449.6 kg-day data, with a minimum of ${\rm{\kappa=1.3 \times 10^{-15}}}$ at ${\rm{m_V=200\ eV/c^2}}$., Comment: 5 pages, 6 figures

We present weakly interacting massive particles (WIMPs) search results performed using two approaches of effective field theory from the China Dark Matter Experiment (CDEX), based on the data from both CDEX-1B and CDEX-10 stages. In the nonrelativistic effective field theory approach, both time-integrated and annual modulation analyses were used to set new limits for the coupling of WIMP-nucleon effective operators at 90% confidence level (C.L.) and improve over the current bounds in the low $m_{\chi}$ region. In the chiral effective field theory approach, data from CDEX-10 were used to set an upper limit on WIMP-pion coupling at 90% C.L. We for the first time extended the limit to the $m_{\chi}, Comment: version accepted by Science China-PMA, 8 pages, 8 figures

We present the improved constraints on couplings of solar axions and more generic bosonic dark matter particles using 737.1 kg-days of data from the CDEX-1B experiment. The CDEX-1B experiment, located at the China Jinping Underground Laboratory, primarily aims at the direct detection of weakly interacting massive particles using a p-type point-contact germanium detector. We adopt the profile likelihood ratio method for analysis of data in the presence of backgrounds. An energy threshold of 160 eV was achieved, much better than the 475 eV of CDEX-1A with an exposure of 335.6 kg-days. This significantly improves the sensitivity for the bosonic dark matter below 0.8 keV among germanium detectors. Limits are also placed on the coupling $g_{Ae} < 2.48 \times 10^{-11}$ from Compton, bremsstrahlung, atomic-recombination and de-excitation channels and $g^{eff}_{AN} \times g_{Ae} < 4.14 \times 10^{-17}$ from a $^{57}$Fe M1 transition at 90\% confidence level., version accepted by PRD, 9 pages, 11 figures

We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses ($m_{\chi}$) via WIMP-nucleus spin-independent scattering with Migdal effect incorporated. Analysis on time-integrated (TI) and annual modulation (AM) effects on CDEX-1B data are performed, with 737.1 kg$\cdot$day exposure and 160 eVee threshold for TI analysis, and 1107.5 kg$\cdot$day exposure and 250 eVee threshold for AM analysis. The sensitive windows in $m_{\chi}$ are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on $\sigma_{\chi N}^{\rm SI}$ at 90\% confidence level are derived as $2\times$10$^{-32}\sim7\times$10$^{-35}$ $\rm cm^2$ for TI analysis at $m_{\chi}\sim$ 50$-$180 MeV/$c^2$, and $3\times$10$^{-32}\sim9\times$10$^{-38}$ $\rm cm^2$ for AM analysis at $m_{\chi}\sim$75 MeV/$c^2-$3.0 GeV/$c^2$., Comment: 5 pages, 4 figures

Using a dense seismic array in Long Beach, California, we have investigated the effectiveness of using traffic noise for passive subsurface imaging. Spectral analysis revealed that traffic-induced vibrations dominate the ambient seismic noise field at frequencies between 3 and 15 Hz. Using the ambient-noise crosscorrelation technique at these frequencies, we have extracted fundamental- and first-order-mode Rayleigh waves generated by Interstate 405 and local roads. We picked group traveltimes associated with the fundamental mode and used them in a straight-ray tomography procedure to produce group velocity maps at 3.0 and 3.5 Hz. The velocity trends in our results corresponded to shallow depths and coincided well with lithologies outlined in a geologic map of the survey area. The most prominent features resolved in our velocity maps were the low velocities to the north corresponding to less-consolidated materials, high velocities to the south corresponding to more-consolidated materials, a low-velocity zone corresponding to artificial fill in Alamitos Bay, and a low-velocity linear feature in the Newport-Inglewood Fault Zone. Our resulting near-surface velocities can be useful for identifying regions that are susceptible to serious damage during earthquake-related shaking.

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10^{-42} and 3×10^{-36} cm^{2} at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (m_{χ}) of 5 GeV/c^{2} are achieved. The lower reach of m_{χ} is extended to 2 GeV/c^{2}.

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10−42 and 3×10−36 cm2 at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (mχ) of 5 GeV/c2 are achieved. The lower reach of mχ is extended to 2 GeV/c2.

We retrieve P diving waves by applying seismic interferometry to ambient-noise records observed at Long Beach, California, and invert travel times of these waves to estimate 3-D P wave velocity structure. The ambient noise is recorded by a 2-D dense and large network, which has about 2500 receivers with 100 m spacing. Compared to surface wave extraction, body wave extraction is a much greater challenge because ambient noise is typically dominated by surface wave energy. For each individual receiver pair, the cross-correlation function obtained from ambient-noise data does not show clear body waves. Although we can reconstruct body waves when we stack correlation functions over all receiver pairs, we need to extract body waves at each receiver pair separately for imaging spatial heterogeneity of subsurface structure. Therefore, we employ two filters after correlation to seek body waves between individual receiver pairs. The first filter is a selection filter based on the similarity between each correlation function and the stacked function. After selecting traces containing stronger body waves, we retain about two million correlation functions (35% of all correlation functions) and successfully preserve most of body wave energy in the retained traces. The second filter is a noise suppression filter to enhance coherent energy (body waves here) and suppress incoherent noise in each trace. After applying these filters, we can reconstruct clear body waves from each virtual source. As an application of using extracted body waves, we estimate 3-D P wave velocities from these waves with travel time tomography. This study is the first body wave tomography result obtained from only ambient noise recorded at the ground surface. The velocity structure estimated from body waves has higher resolution than estimated from surface waves.

We report the results of searches for solar axions and galactic dark matter axions or axion-like particles with CDEX-1 experiment at the China Jinping Underground Laboratory, using 335.6 kg-days of data from a p-type point-contact germanium detector. The data are compatible with the background model and no excess signals are observed. Limits of solar axions on the model independent coupling $g_{Ae}

Summary Using recordings from a dense seismic array in Long Beach, California, USA, we demonstrate the effectiveness of using traffic noise for shallow subsurface imaging. Using the ambient-noise cross-correlation technique at frequencies greater than 3 Hz, we extract fundamental- and first-order-mode Rayleigh waves generated by Interstate 405 and local roads. We use group travel times associated with the fundamental mode in a weighted straight-ray tomography procedure to produce group velocity maps at 3.0 Hz and 3.5 Hz. The velocity trends in our results correspond to shallow depths and coincide well with lithologies outlined in a geologic map of the survey area. The most prominent features resolved in our velocity maps are the low velocities in the north corresponding to less-consolidated materials, high velocities in the south corresponding to more-consolidated materials, a low-velocity zone corresponding to artificial fill in Alamitos Bay, and a low-velocity linear feature in the Newport-Inglewood Fault Zone.

We present the effects of proton irradiations on n-GaN and InGaN/GaN light emitting diodes (LEDs) investigated by secondary ion mass spectrometry (SIMS), circular transmission line model (CTLM), Raman and photoluminescence (PL) measurements. The SIMS results show that the depth of proton implantation is nearly proportional to the energy of the hot protons. Proton implantation can result in the quenching in the luminescence and the degradation in the conductivity of n-GaN, which were found to be preserved to the temperature for device processing of 750 °C. It was found that the intermixing of quantum wells (QWs) induced by proton radiations is negligible, and it is interesting to point out that InGaN/GaN QWs are more resistant to proton irradiations compared with the conventional III–V semiconductor QWs. Our results demonstrate the application of proton irradiations to the technology of electrical and optical isolation for the fabrications of compound semiconductor devices. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We report results of a search for light weakly interacting massive particle (WIMP) dark matter from the CDEX-1 experiment at the China Jinping Underground Laboratory (CJPL). Constraints on WIMP-nucleon spin-independent (SI) and spin-dependent (SD) couplings are derived with a physics threshold of 160 eVee, from an exposure of 737.1 kg-days. The SI and SD limits extend the lower reach of light WIMPs to 2 GeV and improve over our earlier bounds at WIMP mass less than 6 GeV., Comment: 10 pages, 10 figures

We report results of a search for light dark matter weakly interacting massive particles (WIMPs) with CDEX-1 experiment at the China Jinping Underground Laboratory, based on 53.9 kg-days of data from a p -type point-contact germanium detector enclosed by a NaI(Tl) crystal scintillator as anti-Compton detector. The event rate and spectrum above the analysis threshold of 475 eVee are consistent with the understood background model. Part of the allowed regions for WIMP-nucleus coherent elastic scattering at WIMP mass of 6–20 GeV are probed and excluded. Independent of interaction channels, this result contradicts the interpretation that the anomalous excesses of the CoGeNT experiment are induced by dark matter, since identical detector techniques are used in both experiments.

One approach to describe the properties of a complex earth system is to use stochastic methods to characterize statistical variability of seismic velocity (Mai and Beroza (2002)). A stochastic modeling approach requires input in the distributions of the model parameters of interest. A spatial field of distributions for each model point describes the spatial variation of velocity. In this work, we use cross-correlations from a Long Beach region data set of ambient seismic noise recordings to perform eikonal tomography for phase velocity. We use Delaunay triangles as our basis for discretizing the model and represent the velocity model as a distribution for each triangle. We take advantage of the fact that our data provides extensive numbers of correlations for each receiver to build histogram distributions of phase velocity for each triangle. These distributions can be integrated with other models to help make inferences about the nature of the geology and tectonics of the region. Besides forming an input to stochastic modeling, these distributions can be used to generate maps of average velocity. Our map of average velocities clearly shows fault lines that are known to traverse the survey.

The density and duration of the Long Beach, California passive seismic array makes it well-suited for applying ambient noise cross-correlation at high frequencies (3 Hz to 9 Hz). By correlating noise at these frequencies, both Rayleigh-wave and body-wave energy can be recovered. Here, we attempt to understand the origin of this energy. Beamforming reveals that Rayleigh-wave energy is generated by traffic noise, and it is particularly strong near Interstate 405. Virtual source gathers along a line of receivers perpendicular to the highway reinforces this observation. By summing over different virtual source-receiver azimuths, we find that body-wave energy arrives from north-northwest of the array. By looking at correlation results from various patches of virtual source-receiver pairs, we find that body-wave energy is strongest in the center of the array.

The China Dark matter Experiment collaboration reports the first experimental limit on WIMP dark matter from 14.6 kg-day of data taken with a 994 g p-type point-contact germanium detector at the China Jinping underground Laboratory where the rock overburden is more than 2400 m. The energy threshold achieved was 400 eVee. According to the 14.6 kg-day live data, we placed the limit of N= 1.75 * 10^{-40} cm^{2} at 90% confidence level on the spin-independent cross-section at WIMP mass of 7 GeV before differentiating bulk signals from the surface backgrounds., Comment: 5 pages, 5 figures

The dense seismic array in Long Beach, California is located in an urban environment along the Pacific Ocean. There are a variety of noise sources influencing the ambient seismic noise field, both natural (such as the Pacific Ocean) and anthropogenic (such as traffic) in origin. To understand the temporal and spatial influences of these sources, we calculate noise power spectral densities (PSD). From spatial maps of noise PSD, we find that energy from the Pacific Ocean dominates the noise field at frequencies below 2 Hz, while energy from roads and Interstate 405 dominate the noise field at frequencies above 2 Hz. From maps of noise PSD over time, or spectrograms, we observe diurnal fluctuations in energy that are in accord with expected fluctuations in human activity. We expect the noise source distribution to be more homogeneous at higher frequencies, and this is in agreement with ambient noise cross-correlation results at frequencies spanning 0.5 Hz to 2 Hz and 2 Hz to 4 Hz.

Weakly Interacting Massive Particles (WIMPs) are the candidates of dark matter in our universe. Up to now any direct interaction of WIMP with nuclei has not been observed yet. The exclusion limits of the spin-independent cross section of WIMP-nucleon which have been experimentally obtained is about 10^{-7}pb at high mass region and only 10^{-5}pb} at low mass region. China Jin-Ping underground laboratory CJPL is the deepest underground lab in the world and provides a very promising environment for direct observation of dark matter. The China Dark Matter Experiment (CDEX) experiment is going to directly detect the WIMP flux with high sensitivity in the low mass region. Both CJPL and CDEX have achieved a remarkable progress in recent two years. The CDEX employs a point-contact germanium semi-conductor detector PCGe whose detection threshold is less than 300 eV. We report the measurement results of Muon flux, monitoring of radioactivity and Radon concentration carried out in CJPL, as well describe the structure and performance of the 1 kg PCGe detector CDEX-1 and 10kg detector array CDEX-10 including the detectors, electronics, shielding and cooling systems. Finally we discuss the physics goals of the CDEX-1, CDEX-10 and the future CDEX-1T detectors., 36pages,39 figures

Serotonin (5-HT) has been established as a regulator of ciliary beating in numerous systems. In early embryos of Helisoma trivolvis, a cilia-driven rotational movement is modulated by the release of endogenous serotonin from a pair of embryonic neurons, ENC1s, directly onto the ciliated epithelium. The present study was undertaken to examine the signal transduction mechanisms underlying serotonin-mediated cilio-excitation in Helisoma trivolvis embryos. Using time-lapse videomicroscopy, the ciliary beat frequency (CBF) of cultured embryonic ciliated cells was measured in response to various pharmacological manipulations. Serotonin increased CBF in a dose-dependent manner. Addition of 8-bromo-cyclic AMP, isobutylmethylxanthine (IBMX) or a combination of forskolin and IBMX, treatments that elevate the concentration of intracellular cyclic AMP, did not mimic the serotonin-induced increase in CBF. Thus, cyclic AMP does not appear to be involved in the regulation of CBF in this system. In contrast, depolarizing the cells with KCl or veratridine, and artificially raising the intracellular Ca2+ concentration with thapsigargin or A23187, caused a serotonin-like increase in CBF. Furthermore, the serotonin response was abolished in a Ca2+-depleted medium or in a medium containing the L-type Ca2+ channel blockers verapamil or nifedipine. These results suggest that serotonin-stimulated cilio-excitation in cultured Helisoma trivolvis cells involves an influx of Ca2+ to increase intracellular Ca2+ concentration. The link between serotonin–receptor binding and Ca2+ influx in these cells has yet to be determined.

Nitric oxide synthase (NOS) immunoreactivity is present in goldfish gonadotrophs. The present study investigated whether two native goldfish gonadotrophin-releasing hormones (GnRHs), salmon (s)GnRH and chicken (c)GnRH-II, use NOS/nitric oxide (NO) and soluble guanylate cyclase (sGC)/cyclic (c)GMP/protein kinase G (PKG) signalling to stimulate maturational gonadotrophin [teleost gonadotrophin-II, luteinising hormone (LH)] release. In cell column perifusion experiments with dispersed goldfish pituitary cells, the application of three NOS inhibitors (aminoguanidine hemisulphate, 1400W and 7-nitroindazole) and two NO scavengers [2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) and rutin hydrate] reduced sGnRH-elicited, but not cGnRH-II-induced, LH increases. The NO donor sodium nitroprusside (SNP) increased NO production in goldfish pituitary cells in static incubation. SNP-stimulated LH release in column perifusion was attenuated by PTIO and the sGC inhibitor 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-oneon (ODQ), and additive to responses elicited by cGnRH-II, but not sGnRH. ODQ and the PKG inhibitor KT5823 decreased sGnRH- and cGnRH-II-stimulated LH release. Similarly, the LH response to dibutyryl cGMP was reduced by KT5823. These results indicate that, although only sGnRH uses the NOS/NO pathway to stimulate LH release, both GnRHs utilise sGC/PKG to increase LH secretion.

Ghrelin (GRLN) and its receptor have been identified and characterised in goldfish brain and the pituitary, and recent evidence shows that goldfish (g)GRLN(19) induces both growth hormone (GH) and maturational gonadotrophin (LH) release through an extracellular Ca(2+) -dependent mechanism in goldfish. To further understand the role of GRLN in hormone release, the present study examined the involvement of protein kinase C (PKC) and protein kinase A (PKA) in gGRLN(19) -induced GH and LH release and corresponding Ca(2+) signals in primary cultures of goldfish pituitary cells. Treatments with PKC inhibitors, Bis-II and Gö 6976, significantly reduced gGRLN(19) -induced GH and LH release and their corresponding intracellular Ca(2+) signals in identified somatotrophs and gonadotrophs, respectively. gGRLN(19) was unable to further stimulate hormone release or Ca(2+) signals when cells were pretreated with the PKC agonist, DiC8. PKA inhibitors, H-89 and KT 5720, inhibited gGRLN(19) -induced LH release and Ca(2+) signals in gonadotrophs but not GH release or Ca(2+) signals in somatotrophs. Interestingly, pretreatment of pituitary cells with the adenylate cyclase activator forskolin potentiated gGRLN(19) -induced GH, but not LH, release, although it had no effect on intracellular Ca(2+) signals in either cell type. Taken together, the results suggest that PKC is an important intracellular component in gGRLN(19) -induced GH and LH release, whereas PKA is involved in gGRLN(19) -elicited LH release. Furthermore, the PKA pathway potentiates gGRLN(19) -induced GH release via a Ca(2+) -independent mechanism. Overall, the present study provides insight into the neuroendocrine regulation of GH and LH release by elucidating the mechanistic aspects of GRLN, a hormone involved in many critical physiological processes, including pituitary functions.

Previous microarray analyses of the goldfish hypothalamus led us to hypothesise that dopamine could potentially inhibit the excitatory effects of glutamate on luteinising hormone (LH). Post-spawning female goldfish were pre-treated (-4.5 h) with either saline (C; control), SCH 23390 (S; D(1) -receptor antagonist) or sulpiride (L; D(2) -receptor antagonist), followed by an i.p. injection, at -0.5 h, of saline or the glutamate agonist AMPA (A, SA or LA). Blood, hypothalamus and telencephalon tissues were collected. Serum LH was not affected in the S, L, A, or LA groups relative to control as determined by radioimmunoassay. The SA group, however, showed a 289% (P0.0005) increase in serum LH compared to either treatment alone or control. Real-time reverse transcriptase-polymerase chain reaction identified the mRNAs for ionotropic (Gria2a, Gria4) glutamate receptor subunits, activin βa, isotocin, and cGnRH-II as being significantly affected by some of the treatments. The same experiment conducted with sexually-regressed female fish showed a very different LH profile, indicating that this mechanism is seasonally-dependent. We also show that i.p. injection of 1 μg/g isotocin was able to increase LH levels by 167% in sexually regressed female fish relative to controls. Taken together, these results demonstrate that blockage of the D(1) receptor primes post-spawning goldfish for AMPA-stimulated LH release, and provides further insights into the central regulation of reproduction.

The Fontan procedure is frequently used for correction of complex congenital heart disease, but the postoperative morbidity and mortality rates are still high. The results in 35 consecutive patients who underwent the Fontan procedure from January 1980 to June 1991 are reviewed. The patients comprised 26 boys and nine girls aged from 1.7 to 14.8 (mean 6.8) years. The underlying diseases were univentricular heart (19 patients), tricuspid atresia (eight), complete atrioventricular canal (three patients, two of whom had straddling atrioventricular valve) and other conditions (five). Valved conduits were implanted in four patients and non-valved in 15. Direct right atrium-pulmonary artery anastomosis was performed in 16 patients. The overall hospital mortality rate was 23% (eight patients); in the final year of the review it was 11%. Follow-up of the survivors ranged from 1 to 120 (mean 25) months. All except two patients attained New York Heart Association functional class I or II. Three patients underwent reoperation for atrioventricular valve regurgitation and conduit stenosis with good results. It is concluded that the Fontan procedure is a good palliative operation for complex congenital heart disease.

Message encoding for three isoforms of somatostatin (SS) peptides, SS-14, goldfish brain (gb)SS-28 and [Pro²]SS-14, are expressed in goldfish hypothalamus and pituitary tissues. All three native goldfish SSs are active in reducing basal and stimulated growth hormone (GH) responses in cultured goldfish pituitary cells, although with different potencies and efficacies. In the present study, we examined the effects of these three endogenous SSs on electrophysiological properties of goldfish somatotrophs and their physiological relevance. Voltage-sensitive K+ , Ca²+ and Na+ channels in identified goldfish somatotrophs in primary culture were isolated using whole-cell, amphotericin B-perforated patch-clamp techniques. None of the three SSs affected Na+ currents but all three SSs increased maximal K+ current magnitude, with SS-14 being the most effective. [Pro²]SS14 did not affect Ba²+ currents through voltage-sensitive Ca²+ channels but SS14 decreased the magnitude of early and late Ba²+ currents, whereas gbSS-28 reduced that of the late Ba²+ current. Under current-clamp conditions, SS14 and gbSS28 attenuated evoked action potential magnitudes by 34% and 18%, respectively, although [Pro²]SS14 had no effects. However, all three SSs decreased basal intracellular Ca²+ levels ([Ca²+ ](i)) and suppressed basal GH release. These data suggest that, although the ability of SS-14 and gbSS-28 to decrease basal [Ca²+](i) and GH release can be explained, at least in part, by their attenuating effects on cell excitability and current flow through voltage-sensitive Ca²+ channels, [Pro²]SS14-induced reduction in GH responses and [Ca²+](i) cannot be explained by changes in Ca²+ channel properties.

Curing is one of the most important steps in the tire manufacturing process. During this process, a green tire is formed to the desired shape and the compound is converted to a strong, elastic material to meet tire performance needs. The process of curing, commonly called vulcanization, is usually accomplished under pressure and an elevated temperature provided by the mold. The curing process is energy-consuming and has a strong effect on material properties. To attain an optimal state of cure for different compounds of various dimensions at minimal capital and energy costs requires proper evaluation of the state of cure in a tire. Various numerical models have been proposed to determine the state of cure of rubber compounds in molds. Their applications are limited to simple geometry and boundary conditions. For a tire, which has complex shape and variable boundary conditions, the finite element method appears to be an ideal candidate because of its versatility. In this paper, a commercial finite element code, ABAQUS, is used to determine the temperature history of a tire in the curing press. In order to evaluate the state of cure throughout a tire, a user subroutine, HETVAL, is implemented. In the subroutine, the state of cure is determined based on the temperature history using a selected kinetic model, whose cure rate parameters are obtained from moving die rheometer (MDR) measurements. The heat generation due to chemical reaction is also included. The evaluation of the state of cure using the finite element method is benchmarked using a number of rubber compounds with simple geometries and boundary conditions. Both isothermal and nonisothermal conditions are tested. The predicted temperature history of a tire is then verified by the temperature history obtained from the thermocouples embedded in the tire. Parametric studies are carried out to evaluate the effect of various temperature histories on the state of cure in a tire. The results are used to shorten the curing cycle.

Three destructive tire tests, burst pressure, high speed free rotation, and DOT plunger energy are performed to check the ultimate strength of new tires. These tests represent some of the extreme, although unusual, overload conditions that may be applied to a tire. They are used to determine how far above normal service conditions one might take a tire before it reaches its ultimate strength. A nonlinear incompressible rubber model and a nonlinear cord-rubber composite model were used in the tire analyses. Various rubber compounds as well as the rubber in the cord-rubber composite were modeled as nonlinear incompressible Mooney-Rivlin materials. The bimodulus cord and the cord angle change effect due to deformation were also considered. In addition, gap elements were used at the tire-rim interface and between tread grooves where required to provide appropriate boundary conditions. Numerical simulations of these destructive tire tests represent three excellent benchmarks to verify and to evaluate the robustness of a finite element code due to very large strain and deformation occurring in the tire. The numerical results predicted by the finite element tire models agreed very well with the available experimental data.

The involvement of intracellular Ca(2+) stores and their regulatory mechanisms in mediating pituitary adenylate cyclase-activating polypeptide (PACAP) stimulation of growth hormone (GH) and maturational gonadotrophin (GTH-II) secretion from goldfish pituitary cells was investigated using a cell column perifusion system. Pretreatment with caffeine abolished the GH and GTH-II responses to PACAP. Dantrolene attenuated PACAP-elicited GTH-II release but did not affect the GH response, whereas ryanodine and 8-bromo-cADP ribose did not alter PACAP-induced GH and GTH-II release. Two endoplasmic/sarcoplasmic reticulum Ca(2+) ATPase (SERCA) inhibitors, thapsigargin and cyclopiazonic acid, augmented PACAP-induced GTH-II release; similarly, thapsigargin elevated GH responses to PACAP. Treatment with carbonyl cyanide m-chlorophenylhydrazone, a mitochondrial uncoupler, reduced PACAP-stimulated GH release; however, inhibition of the mitochondrial Ca(2+) uniport by Ru360 did not affect GH and GTH-II responses. The phosphatidyl inositol (PI)-specific phospholipase C (PLC) inhibitor ET-18-OCH(3) inhibited, whereas the phosphatidyl-choline (PC)-specific PLC inhibitor D609 enhanced, PACAP-stimulated GH and GTH-II responses. On the other hand, the IP(3) receptor blocker xestospongin D had no effect on PACAP-induced GTH-II response and potentiated the GH response. These results suggest that, despite some differences between GH and GTH-II cells, PACAP actions in both cell types generally rely on a caffeine-sensitive, but a largely ryanodine receptor-independent, mechanism. PC-PLC and some SERCA negatively modulate PACAP actions but mitochondrial Ca(2+) stores per se are not important. A novel PI-PLC mechanism, which does not involve the traditional IP(3)/Ca(2+) pathway, is also suggested.

Using single-cell Ca(2+) imaging and a growth hormone (GH) radioimmunassay, we investigated somatostatin-14 (SS(14)) inhibition of cAMP-dependent, stimulated GH secretion from primary cultures of dispersed goldfish pituitary cells. The dopamine-D1 receptor agonist SKF-38393, and the hypothalamic neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) both elevated intracellular Ca(2+) concentration ([Ca(2+)](i)) and stimulated GH release. When increases in [Ca(2+)](i) were prevented by intracellular loading of BAPTA, a Ca(2+) chelator, SKF-38393- and PACAP-stimulated GH release were inhibited, suggesting that these Ca(2+) signals are required for stimulated GH release. SS(14) inhibited SKF-38393- and PACAP-stimulated GH release, but did not prevent these Ca(2+) signals. Kinetic analysis revealed that SS(14) lowered the maximum amplitude of the SKF-38393- and PACAP-evoked Ca(2+) responses, but had no effect on other aspects of the Ca(2+) signal. We then examined the ability of SS(14) to act subsequent to dopamine-D1 or PACAP receptor activation using the adenylate cyclase activator forskolin, or the membrane permeant cAMP analogue 8Br-cAMP. Forskolin and 8Br-cAMP both increased [Ca(2+)](i) and GH secretion and, as expected, SS(14) inhibited the resultant GH release. Although SS(14) significantly increased the time to maximum amplitude of the forskolin-evoked Ca(2+) signals, it had no detectable effect on any of the kinetic parameters used to describe the Ca(2+) signals evoked by 8Br-cAMP. Taken together, these results establish that SS(14) has the ability to suppress Ca(2+)-dependent exocytosis by acting distal to elevations in [Ca(2+)](i). Furthermore, it appears likely that the cellular mechanisms underlying the observed effects of SS(14) on Ca(2+) signalling are upstream of cAMP and may be unrelated to those responsible for inhibiting GH release.

Prosthetic arteriovenous accesses are the last resort after efforts to place autogenous accesses are exhausted. During reimplantation of the graft, it is sometimes not convenient to dissect out the vessels to be grafted, especially around the venous anastomotic site and under local anesthesia.We describe a technique using the ringed PTFE graft for the construction of a reverse upper arm curved graft in 14 patients who had received upper arm grafts previously.The mean operative time was 61+/-13 minutes, and the follow-up interval extended to 20 months. No infections, pseudoaneurysm formations, or steal syndrome occurred during the follow-up period. The primary patency rate was calculated by Kaplan-Meier analysis, and the primary patency from graft insertion to clotting in the reverse graft was 91% at 3 months, 83% at 6 months, 66% at 9 months, and 57% at 12 months.These results suggest that using the reverse upper arm curved graft during the reimplantation procedure was an alternative prosthetic arteriovenous access with the advantage of less tissue dissection, shorter operation time, and favorable patency rate.

The involvement of nitric oxide (NO) in the regulation of goldfish growth hormone (GH) secretion was further characterized using primary cultures of dispersed goldfish pituitary cells. Western blots revealed the presence of an inducible nitric oxide synthase (iNOS)-like protein of approximately 120 kDa in cytosol/plasma membrane extracts. By contrast, brain NOS-immunoreactive proteins of approximately 120-140 kDa were occasionally detected in a cytoskeleton/organelle fraction but were absent from cytosol/plasma membrane extracts. The NO donor sodium nitroprusside (SNP) acutely increased GH secretion but this response was not observed in the presence of either a NO scavenger (PTIO) or a soluble guanylate cyclase inhibitor (ODQ). SNP also significantly increased the levels of cyclic (c)GMP in somatotrope-enriched cell populations. Treatments with 1400W (iNOS inhibitor), PTIO and rutin hydrate (NO scavengers) and ODQ abolished the acute GH-release response to two endogenous gonadotropin-releasing hormones (GnRH). 1400W, rutin hydrate, PTIO and ODQ alone did not significantly alter basal GH secretion. Together, these results establish that an iNOS-like peptide is constitutively present in the pituitary of the goldfish. Furthermore, these data suggest that NO, most likely through the generation of cGMP, is a necessary signal transduction component of GnRH-induced GH secretion.

Video-assisted thoracoscopic surgery for parathyroid glands deep in the mediastinum is a safe and successful procedure, but its success depends on accurate localization before operation. Recently, a variety of minimally invasive techniques to approach cardiovascular disease have been proposed to eliminate the morbidity of standard sternotomy. We describe a case involving a 71-year-old woman with persistent hyperparathyroidism resulting from an ectopic mediastinal parathyroid gland, which was removed through an upper sternotomy. The technique has proved safe, effective, and aesthetically acceptable to the patient.

We examined whether distinct Ca2+ stores differentially control basal and gonadotropin (GTH-II)-releasing hormone (GnRH)-evoked GTH-II release, long-term GTH-II secretion and contents, and GTH-II-beta mRNA expression in goldfish. Thapsigargin (Tg)-sensitive Ca2+ stores mediated neither caffeine-evoked GTH-II release, nor salmon (s)GnRH- and chicken (c)GnRH-II-stimulated secretion; the latter responses were previously shown to involve ryanodine (Ry)-sensitive Ca2+ stores. Surprisingly, Tg decreased basal GTH-II release. This response was attenuated by prior exposure to sGnRH and caffeine, but was insensitive to the phosphatase inhibitor okadaic acid, the inhibitor of constitutive release brefeldin A and cGnRH-II. GTH-II-beta mRNA expression was decreased at 24 h by 2 microm Tg, and by inhibiting (10 microm Ry) and stimulating (1 nm Ry) Ry receptors. Transient increases in GTH-II-beta mRNA were observed at 2 h and 12 h following 10 microm and 1 nm Ry treatment, respectively. Effects of Tg, Ry and GnRH on long-term GTH-II secretion, contents and apparent production differed from one another, and these changes were not well correlated with changes in GTH-II-beta mRNA expression. Our data show that GTH-II secretion, storage and transcription can be independently controlled by distinct Ca2+ stores.

Aneurysm of the sinus of Valsalva (ASV) is a rare anomaly. It may be congenital or acquired basis. In pediatric patients, most are congenital in origin. It is frequently associated with other congenital disease, most frequently ventricular septal defect (VSD). Pathologically, this is due to the total absence of normal elastic fibers. Patients with ASV are generally asymptomatic unless aneurysm rupture occurs. Unruptured ASV with right ventricular outflow tract (RVOT) obstruction is very rare. Herein we describe an unusual ASV with RVOT obstruction associated with VSD in a 14-year-old boy. He had experienced heart failure and exertional dyspnea for 2 months. The diagnosis was made by echocardiography, angiography and surgery. After surgical repair of the VSD and resection of the ASV, dyspnea and heart failure were relieved. The patient remained well during the 3 years of follow-up.

The effects of K+ channel blockers on basal gonadotropin II (GTH-II) release were examined in cultured goldfish gonadotropes. Tetraethylammonium (TEA) inhibited basal GTH-II release, whereas 4-aminopyridine (4-AP) increased basal release, although both K+ channel blockers generated increases in [Ca2+]i. Other K+ channel blockers had no significant effect on GTH-II release. We examined whether Ca2+ entry that arises from blockade of K+ channels by 4-AP mediates the secretory response. Secretion evoked by 4-AP was slightly reduced by TEA but was unaffected by reducing Ca2+ entry using either an inhibitor of Ca2+ channels, verapamil, or nominally Ca2+-free medium. In contrast, the Ca2+ signal evoked by 4-AP was largely blocked by Ca2+-free medium, as predicted by its inhibitory action on K+ channels. Together, these data suggest that the hormone release response to 4-AP is independent of entry of extracellular Ca2+. Finally, the mechanism of hormone release evoked by 4-AP appeared to be independent of mechanism(s) evoked by caffeine since 4-AP did not affect caffeine-evoked release and caffeine did not affect 4-AP evoked release. That both 4-AP and TEA generated Ca2+ signals but affected hormone release in either an extracellular Ca2+ independent (4-AP) or inhibitory (TEA) manner suggests that Ca2+ entry is linked to GTH-II secretion in a highly nonlinear fashion.

Residual epicardial constriction after pericardiectomy prevents good results. The Waffle procedure, incising the fibrotic epicardium in a crosshatched manner, is frequently used to release the epicardial constriction. In this report, we describe a modification of the Waffle procedure, which uses the electrocautery unit and watching the standard monitoring equipment for arrhythmia, to perform multiple epicardial incisions.

Pituitary adenylate cyclase-activating polypeptide (PACAP) has recently been shown to be a hypophysiotropic factor in the goldfish. In this study, we examined the mechanisms of PACAP action on goldfish maturational gonadotropin (GTH-II) release using primary cultures of pituitary cells. The GTH-II response to mammalian PACAP1-38 (mPACAP) was inhibited by a PACAP receptor antagonist suggesting a receptor-mediated action. Addition of either an adenylate cyclase inhibitor or a protein kinase A (PKA) inhibitor reduced the mPACAP-induced GTH-II release. In addition, when GTH-II release was already stimulated by either forskolin or 8-bromo-cAMP (8Br-cAMP), mPACAP did not further increase GTH-II secretion. These results strongly implicated the involvement of an adenylate cyclase/cAMP/PKA pathway in PACAP-stimulated GTH-II release. Although mPACAP induced a rise in intracellular Ca2+ level in identified gonadotropes, results with voltage-sensitive Ca2+ channel inhibitors indicated that the GTH-II responses to mPACAP, forskolin and 8Br-cAMP did not depend upon Ca2+ entry through these channels. Two protein kinase C (PKC) inhibitors did not affect mPACAP-elicited GTH-II release, and mPACAP further increased GTH-II secretion in the presence of PKC activators. These results indicate that PKC-dependent elements are not essential for the stimulatory action of mPACAP in gonadotropes. Interestingly, while GTH-II responses to a stimulatory concentration of mPACAP were additive to responses elicited by maximal effective concentrations of two endogenous gonadotropin releasing hormones (GnRHs), a subthreshold concentration of mPACAP potentiated GnRH and PKC activator stimulation of GTH-II secretion. Similarly, submaximal concentrations of forskolin potentiated the GTH-II response to the PKC activator, tetradecanoyl phorbol acetate. These data suggest that PACAP and its cAMP-dependent signalling mechanisms provide an alternate stimulatory input to goldfish gonadotropes and may influence the effectiveness of the major neuroendocrine control exerted by the PKC-dependent GnRH signalling pathway.

A method was developed and validated for determination and quantitation of tilmicosin residues in swine, cattle, and sheep edible tissues, as well as chicken fat, skin, and muscle over a concentration range of 0.025 microg/g-20 microg/g. For chicken kidney and liver, the method was validated over a range of 0.060 microg/g-20 microg/g. The tissue sample was extracted with methanol and a C18 cartridge was used for solid-phase extraction cleanup. A reversed-phase gradient liquid chromatographic method with detection at 280 nm was used to separate the tilmicosin from matrix components in 30 min run time. The limit of quantitation (LOQ) of the method was 0.025 microg/g for all tested tissues except chicken kidney and liver, for which the LOQ was 0.06 microg/g. Average recoveries for tissue samples ranged from 73 to 98%. Relative standard deviation values ranged from 0.6 to 14.7%.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a novel member of the secretin-glucagon peptide family. In mammals, this peptide has been located in a wide range of tissues and is involved in a variety of biological functions. In lower vertebrates, especially fish, increasing evidence suggests that PACAP may function as a hypophysiotropic factor regulating pituitary hormone secretion. PACAP has been identified in the brain-pituitary axis of representative fish species. The molecular structure of fish PACAP is highly homologous to mammalian PACAP. The prepro-PACAP in fish, however, is distinct from that of mammals as it also contains the sequence of fish GHRH. In teleosts, the anterior pituitary is under direct innervation of the hypothalamus and PACAP nerve fibers have been identified in the pars distalis. Using the goldfish as a fish model, mRNA transcripts of PACAP receptors, namely the PAC1 and VPACI receptors, have been identified in the pituitary as well as in various brain areas. Consistent with the pituitary expression of PACAP receptors, PACAP analogs are effective in stimulating growth hormone (GH) and gonadotropin (GTH)-II secretion in the goldfish both in vivo and in vitro. The GH-releasing action of PACAP is mediated via pituitary PAC1 receptors coupled to the adenylate cyclase-cAMP-protein kinase A and phospholipase C-IP3-protein kinase C pathways. Subsequent stimulation of Ca2+ entry through voltage-sensitive Ca2+ channels followed by activation of Ca2+-calmodulin protein kinase II is likely the downstream mechanism mediating PACAP-stimulated GH release in goldfish. Although the PACAP receptor subtype(s) and the associated post-receptor signaling events responsible for PACAP-stimulated GTH-II release have not been characterized in goldfish, these findings support the hypothesis that PACAP is produced in the hypothalamus and delivered to the anterior pituitary to regulate GH and GTH-II release in fish.

Calcium signals have been implicated in the regulation of many diverse cellular processes. The problem of how information from extracellular signals is delivered with specificity and fidelity using fluctuations in cytosolic Ca2+ concentration remains unresolved. The capacity of cells to generate Ca2+ signals of sufficient spatial and temporal complexity is the primary constraint on their ability to effectively encode information through Ca2+. Over the past decade, a large body of literature has dealt with some basic features of Ca2+-handling in cells, as well as the multiplicity and functional diversity of intracellular Ca2+ stores and extracellular Ca2+ influx pathways. In principle, physiologists now have the necessary information to attack the problem of function- and agonist-specificity in Ca2+ signal transduction. This review explores the data indicating that Ca2+ release from diverse sources, including many types of intracellular stores, generates Ca2+ signals with sufficient complexity to regulate the vast number of cellular functions that have been reported as Ca2+-dependent. Some examples where such complexity may relate to neuroendocrine regulation of hormone secretion/synthesis are discussed. We show that the functional and spatial heterogeneity of Ca2+ stores generates Ca2+ signals with sufficient spatiotemporal complexity to simultaneously control multiple Ca2+-dependent cellular functions in neuroendocrine systems.

The intracellular signal transduction mechanisms mediating maturational gonadotropin and somatotropin secretion in goldfish are reviewed. Several major signaling mechanisms, including changes in intracellular [Ca2+], arachidonic acid cascades, protein kinase C, cyclic AMP/protein kinase A, calmodulin, nitric oxide, and Na+/H+ antiport, are functional in both cell types. However, their relative importance in mediating basal secretion and neuroendocrine-factor-regulated hormone release differs according to cell type. Similarly, agonist- and cell-type-specificity are also present in the transduction pathways leading to neuroendocrine factor-modulated maturational gonadotropin and somatotropin release. Specificity is present not only in the actions of different regulators within the same cell type and with the same ligand in the two cell types, but this also exists between isoforms of the same neuroendocrine factor within a single cell type. Other evidence suggests that function-selectivity of signaling may also result from differential modulation of Ca2+ fluxes from different sources. The interaction of different second messenger systems provide the basis by which regulation of maturational gonadotropin and somatotropin release by multiple neuroendocrine factors can be integrated at the target cell level.