Ramp Time Research Articles

PCR-based fingerprinting techniques for rapid detection of animal species in meat products

A reproducible, rapid, and simple method for simultaneous identification of multiple meat species in a single step DNA-based test has been developed based on the generation of species-specific fingerprintings by two different arbitrary DNA amplification approaches (RAPD- and AP-PCR). Samples representative of various species and meat products submitted to different processing conditions were selected to verify the applicability of the techniques. RAPD-PCR fingerprintings allowed the discrimination amongst pork, beef, lamb, chicken and turkey in all cases. Samples corresponding to each species were clustered together at similarity levels ⩾75%. The DNA profiles consisted of a discrete but reproducible number of bands, which made possible the interpretation of the results by simple visual inspection. AP-PCR also allowed identification of the five tested species in every sample although more complex patterns were generated, including some low intensity bands. In both cases, a ramp time between annealing and extension temperatures was introduced to achieve good reproducibility. Overall, the simplicity of RAPD-PCR patterns could make this technique suitable for meat authentication in routine analysis.

Effect of muscle relaxants on experimental jaw-muscle pain and jaw-stretch reflexes: a double-blind and placebo-controlled trial

A randomised, double-blind, placebo-controlled three-way cross-over study was performed to investigate the effect of two muscle relaxants (tolperisone hydrochloride and pridinol mesilate) on experimental jaw-muscle pain and jaw-stretch reflexes. Fifteen healthy men participated in three randomised sessions separated by at least 1 week. In each session 300 mg tolperisone, 8 mg pridinol mesilate or placebo was administered orally as a single dose. One hour after drug administration 0.3 ml hypertonic saline (5.8%) was injected into the right masseter to produce muscle pain. Subjects continuously rated their perceived pain intensity on an electronic 10-cm visual analogue scale (VAS). The pressure pain threshold (PPT) was measured and short-latency reflex responses were evoked in the pre-contracted (15% maximal voluntary contraction) masseter and temporalis muscles by a standardised stretch device (1 mm displacement, 10 ms ramp time) before (baseline), 1 h after medication (post-drug), during ongoing experimental muscle pain (pain-post-drug), and 15 min after pain had vanished (post-pain). Analysis of variance demonstrated significantly lower VAS peak pain scores (5.9±0.4 cm) after administration of tolperisone hydrochloride compared with pridinol mesilate (6.8±0.4 cm) and placebo (6.6±0.4 cm) ( P=0.020). Administration of pridinol mesilate was associated with a significant decrease in PPTs compared with tolperisone hydrochloride and placebo ( P=0.002) after medication, but not after experimental jaw-muscle pain. The normalised peak-to-peak amplitude of the stretch reflexes were not significantly influenced by the test medication ( P=0.762), but were in all sessions significantly facilitated during ongoing experimental jaw-muscle pain ( P=0.034). In conclusion, tolperisone hydrochloride provides a small, albeit significant reduction in the perceived intensity of experimental jaw-muscle pain whereas the present dose had no effect on the short-latency jaw-stretch reflex.

State selection in Taylor-vortex flow reached with an accelerated inner cylinder

The selection of the axial wavelength in axisymmetric Taylor-vortex flow was studied by numerical experiments where the inner cylinder speed was linearly increased from subcritical to supercritical values over a finite ramp time to values not far above . For impulsive increases of the inner cylinder speed (zero ramp time) the preferred axial wavelength was less than the critical wavelength. As the ramp time was increased, the preferred axial wavelength increased and approached the critical wavelength, so that for very slow increases of the inner cylinder speed the preferred axial wavelength was equal to the critical wavelength. A linear model was developed which revealed that a linearly increased inner cylinder speed resulted in a delayed growth for each of the amplitudes of the modes. When the ramp time was sufficiently large, the amplitude of the mode with the critical wavelength was delayed the least from growing to high amplitudes. This mode then self-interacted and saturated resulting in steady Taylor-vortex flow. Finally, nonlinear effects and state selection are discussed from the point of view of nonlinear dynamics.

Impact of time-ordered measurements of the two states in a niobium superconducting qubit structure

Measurements of thermal activation are made in a superconducting, niobium persistent-current qubit structure, which has two stable classical states of equal and opposite circulating current. The magnetization signal is read out by ramping the bias current of a dc superconducting quantum interference device. This ramping causes time-ordered measurements of the two states, where measurement of one state occurs before the other. This time ordering results in effective measurement time, which can be used to probe the thermal activation rate between the two states. Fitting the magnetization signal as a function of temperature and ramp time allows one to estimate a quality factor of $3\ifmmode\times\else\texttimes\fi{}{10}^{5}$ for our devices, a value favorable for the observation of long quantum coherence times at lower temperatures.

Abnormal phenomenon of the dependence of the retention factors for uncharged species on applied voltage in capillary electrochromatography

Polymethacrylate-based monolithic columns were prepared for capillary electrochromatography (CEC) byin situ copolymerization of butyl methacrylate (BMA), 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and ethylene dimethacrylate (EDMA) in the presence of a porogen in fused-silica capillaries of 100 μm I.D. The abnormal phenomenon that retention factors for neutral species decreases with applied voltage in CEC was observed. Capillary electrophoresis (CE) instruments usually require a period of time to increase voltage from 0 kV to desired value, which is called as ramp time. Such ramp time and any error in the determination of dead time should be taken into account during the accurate calculation of retention factors. After the correction of the retention factors, the plots of the corrected factors for alkylbenzene versus applied voltage were made, the absolute value of the plot slopes are less than 1.8×10−4, which indicates that the corrected retention times for neutral species do not show any dependence on applied voltage. Further, the plats of the corrected retention times for acidic and basic compounds versus the reciprocal of applied voltage were drawn, where the target compounds were eluted in neutral form. The very nice linearity of the plots was obtained. The linear correlation coefficients are over 0.999. Here, the slopes of the plots represent\(\frac{{L_{eff} \cdot L_{tot} \cdot \left( {l + k} \right)}}{{\mu eo}}\), which indicates that retention factors for the test compounds are constants under a given separation condition.

Cored rutherford cables for the GSI fast ramping synchrotron

The new heavy ion synchrotron facility proposed by GSI will have two superconducting magnet rings in the same tunnel, with rigidities of 200 T/spl middot/m and 100 T/spl middot/m. Fast ramp times are needed, which can cause significant problems for the magnets, particularly in the areas of ac loss and field distortion. This paper discusses the 200 T/spl middot/m ring, which will use Cos/spl theta/ magnets based on the RHIC dipole design. We discuss the reasons for choosing Rutherford cable with a resistive core and report loss measurements carried out on cable samples. These measurements are compared with theoretical calculations using measured values of inter-strand resistance. Reasonably good agreement is found, but there are indications of nonuniformity in the adjacent resistance R/sub a/. Using these measured parameters, losses and temperature rise are calculated for a RHIC dipole in the operating cycle of the accelerator. A novel insulation scheme designed to promote efficient cooling is described.

Design, manufacture, and test of a large bore cryogen-free magnet

A large superconducting cryogen-free magnet has been designed, manufactured and tested. The magnet reached 4.1 T in the 430 mm room temperature bore with a ramp time of 35 min. The magnet is cooled by a two-stage GM cryocooler. The magnet can be rotated on a support frame to be operated with either horizontal or vertical bore. The stored energy of 1 MJ can safely be handled during a quench. Homogeneity, cool down as well as quench properties confirmed the design values. The magnet is now being operated by the end user.

Oxidation of nitrogen-implanted silicon: Energy dependence of oxide growth and defect characterization of the silicon substrate

It is well known that nitrogen implantation in silicon leads in reduction of the SiO2 thickness in implanted wafers, which makes this a very promising technique for present and future device processing. In this work we investigate the influence of the implantation energy on oxidation kinetics in nitrogen-implanted silicon. Nitrogen was implanted in silicon wafers at low (3 keV), and medium (25, 80, and 150 keV) energies and oxidations were performed at various temperatures (800–900 °C) and times. The experiment shows that the decrease in the oxide thickness is smaller when nitrogen is implanted closer to the silicon surface. We attribute this to nitrogen out-diffusion during the ramping and the initial oxidation steps, which is more effective when nitrogen is placed closer to the surface. Additional experiments varying the ramping time support this explanation. An additional study of the growth of extended defects under the different implantation conditions has been performed. This study enabled the estimation of an energy-dose “window,” in which we can observe very small oxide thickness (25−40 Å) without extended defects formation.

Determinação direta e simultânea de Al, As, Fe, Mn e Ni em cachaça por espectrometria de absorção atômica em forno de grafite

Este trabalho propõe um método simples, rápido e confiável para determinação direta e simultânea de Al, As, Fe, Mn e Ni em cachaça por espectrometria de absorção atômica em forno de grafite (GFAAS). A superfície superior da plataforma do tubo de grafite foi revestida com filme à base de tungstênio (WxCyOz).O programa de aquecimento otimizado (temperatura, tempo de rampa, tempo de patamar) foi o seguinte: secagem 1 (100ºC, 5 s, 5 s); secagem 2 (120ºC, 5 s, 5 s); pirólise (1300ºC, 10 s, 30 s); atomização (2200ºC, 1 s, 6 s) e limpeza (2550ºC, 1 s, 3s). Os desvios padrões relativos (n=3) foram < 4,4%, < 0,7%, < 11%, < 6,0%, < 1,2% para os elementos Al, As, Fe, Mn e Ni, respectivamente. A exatidão foi avaliada por meio de testes de adição e recuperação dos analitos em 8 amostras de cachaças comerciais, e as recuperações situaram-se nos seguintes intervalos: 80 - 105% (Al), 81 - 92% (As), 82 - 108% (Fe), 83 - 106% (Mn), 83 - 108% (Ni). Os limites de detecção calculados foram 9,7 µg L-1 Al, 2,3 µg L-1 As, 12 µg L-1 Fe, 14 µg L-1 Mn e 0,8 µg L-1 Ni.

Growth of Semi-insulating GaN Layer by Controlling Size of Nucleation Sites for SAW Device Applications

Semi-insulating undoped GaN films were grown based on controlling the size of the nucleation sites through a special two-step growth method: First, 16 nm LT-GaN was annealed at 950 ° with a ramping time of 4 min, then the GaN was grown at this temperature for 1 min. Second, the growth temperature was increased to 1020° with a ramping time of 2 min and the GaN layer finally grown at 1020 ° for 40 min. The film grown by this sequence exhibited sheet resistance of up to 109 Ω/sq with mirror-like surface morphology. By slow ramping to 950° in the initial phase of growth, smaller grain sizes and higher nuclei densities were formed and the columnar growth mode along the c direction was dominant. The observation of higher resistance in two-step growth is believed due to the increased misorientation of nuclei when the growth proceeds during temperature ramping to 1020°. The fabricated saw filter on semi-insulating GaN exhibited a high velocity of 5342 m/s at center frequencies of 133.57 MHz and an electromechanical coupling coefficient(k2) of about 0.763 %, which was enhanced due to the improvement of surface morphology with high sheet resistance by the two- step ramping technique.

Uso combinado de amplificación aleatoria de polimorfismo del ADN (RAPD) y reacción en cadena de la polimerasa (touchdown PCR) en el estudio epidemiológico de Aspergillus fumigatus

Aspergillus fumigatus is a filamentous fungus that acts as an opportunistic pathogen and has emerged as a major problem in immunosuppressed patients. Nosocomial outbreaks of aspergillosis are becoming more frequent, but their identification and epidemiological characterization is slow and difficult. Description of a fast, sensitive, specific method to identify and fingerprint A. fumigatus using methodology available in clinical laboratories. We studied several strains of A. fumigatus isolated from patients with invasive aspergillosis (n = 4), the hospital environment (n = 5) and reference cultures (n = 1), as well as other close phylogenetic fungal species from patients (n = 1), hospital environment (n = 6) and reference cultures (n = 1). A. fumigatus was identified by both touchdown PCR and conventional phenotyping methods. Genotyping was performed with random amplification of polymorphic DNA (RAPD) analysis, comparing the results from two primers (OPZ-19 and R-108) and different amplification protocols with regard to band resolution and reproducibility. Touchdown PCR and phenotype results were identical. Best RAPD results were obtained with the R-108 primer and considerably longer ramp times between annealing and extension. RAPD analysis is a fast, reliable tool for DNA fingerprinting. Patterns may be easier to repeat and interpret when longer ramp times are used. Touchdown PCR combined with RAPD analysis is a sensitive, accurate method for managing clinical outbreaks of Aspergillus fumigatus.

Integrated build: a new approach to building automotive bodies

This paper introduces three auto body build concepts: net build (NB), functional build (FB) and integrated build (IB). Most manufacturers design and validate their vehicle launches using the NB concept. This concept is shown to be expensive, time consuming and not effective value added. Functional build has found growing acceptance as being preferable over NB. FB has tended to find the greatest acceptance as a die buyoff procedure for individual parts based on subassembly quality. Aspects of FB are shown in a case study where the manufacturer claimed to use FB for die development, but critical elements were omitted and opportunities lost. The integrated build (IB) process is an extension of the FB approach. It is a more inclusive process that considers the entire vehicle and requires closer coordination with product design. Aspects of IB are also shown in two case studies. In the first, IB concepts were included in the design process, which enabled the company to implement an effective material introduction strategy. The second is a comparison of the product development timelines of two companies and shows how IB concepts can shorten lead and production ramp time.

Optimization of the separation of Vinca alkaloids by nonaqueous capillary electrophoresis

A rapid method for the determination of Vinca alkaloids by nonaqueous capillary electrophoresis with diode array detection has been developed. A group of 11 alkaloids (catharanthine, vinorelbine, anhydrovinblastine, vinflunine, vindoline, 4- O-deacetylvinorelbine, 4- O-deacetylvinflunine, vindesine, vinblastine, 4′-deoxy-20′,20′-difluorovinblastine, vincristine) could be readily separated within 10 min. The compounds were separated using a capillary of 38 cm effective length, a running buffer composed of 50 m M ammonium acetate and 0.6 M acetic acid in a methanol–acetonitrile (75:25, v/v) mixture. A constant voltage of 25 kV with a ramp time of 1 min and a 344.7×10 3 Pa pressure, applied simultaneously to inlet and outlet buffer vials, were used during sample analysis. Five of these alkaloids were selected for optimization of the separation and for validation studies with respect to specificity, linearity, range, limits of quantification and detection and then accuracy. The feasibility of the assay was demonstrated by analyzing a commercial sample of vinorelbine (Navelbine ®, ampoule at 10 mg/ml of vinorelbine base). The results were compared with a high-performance liquid chromatography method.

Growth parameters for polycrystalline GaN on silica substrates by metalorganic chemical vapor deposition

Polycrystalline GaN was grown on silica glass substrates by metalorganic chemical vapor deposition using a two-step growth process. It was found that the optical and structural properties were significantly dependent on the growth conditions of GaN buffer layers. Growth parameters for the low-temperature buffer layers, such as the growth temperature, the growth time, the trimethyl gallium flow rate and the ramping time, have played important roles in improving the quality of polycrystalline GaN. This tendency is quite similar to the case of a GaN epilayer on a sapphire substrate.

Design studies on superconducting Cos θ magnets for a fast pulsed synchrotron

The new heavy ion synchrotron proposed by GSI will comprise two superconducting magnet rings in the same tunnel, having rigidities of 200 T.m and 100 T.m. Fast ramp times are needed, which can cause significant problems for the magnets, particularly in the areas of ac loss and field distortion. This paper discusses the 200 T.m ring, which will use Cos /spl theta/ magnets based on the RHIC dipole design. We describe options for the low loss Rutherford cable that will be used, together with a novel insulation scheme designed to promote efficient cooling. Measurements of contact resistance in the cable are presented and the results of these measurements are used to predict the ac losses, temperature rise and field distortion in the magnets during fast ramp operation.

Investigation of the solid–liquid transition of highly concentrated suspensions in oscillatory amplitude sweeps

Suspensions of quasimonodisperse polymethylmethacrylate spheres with mean diameters of 4.7 and 3.1 μm, dispersed in a low-molecular-weight polydimethylsiloxane, were characterized using oscillatory shear amplitude sweeps. Thereby, the solid volume concentration was varied. The influence of the sample preparation, the mode of the experiment (controlled shear rate, controlled shear stress), and the parameters of the amplitude sweep such as logarithmic ramp time, measurement time, and frequency were investigated. The logarithmic ramp and the measurement time were found to be the substantial factors which especially influence the experimental results at low shear stress amplitudes. The frequency has an effect only at higher shear stress amplitudes where the material behaves linearly again. All suspensions showed a Hookean solid behavior at low shear stress amplitudes and a Newtonian fluid behavior at high shear stress amplitudes. In the transition range between the Hookean and the Newtonian behavior the analysis of the primary shear strain-time signal showed that the nonlinear effects were coupled with the occurrence of higher odd harmonics.

Effect of palladium modifier on the analyte vapor transport in a graphite furnace atomizer

The effect of Pd modifier on vapor transport of In, Ga, Mn, Pb and Sn in a graphite furnace atomizer was investigated using a Quant-ZETA atomic absorption spectrometer. The fast heating of the furnace (ramp time 0.15–0.25 s) followed by temperature stabilization at 2500–2800 K enabled us to measure the vapor dissipation rate using the ‘tails’ of the atomic absorption signals. The analyte, 0.02–0.5 ng, was vaporized alone or together with Pd. Pd was introduced and thermally treated before the sampling of the analyte. Small amounts of Pd (0.1 μg) significantly changed the vaporization pattern and residence time of the atomic vapors, but affected the peak area only slightly. In this case, the vapor removal is 1.5–1.8 times slower than that predicted by theory for the diffusion mechanism of vapor release. The involvement of vapor adsorption by the wall and molecular diffusion in the vapor transport is suggested. The increase of Pd amount (up to 2.5 μg) causes the gradual reduction of residence time and peak area, due to the increase of diffusion rate of atomic vapor. Using the two-line method of temperature measurement, it is shown that this effect is accompanied by a temperature increase of 75–200 K, when 0.5–4 μg Pd are vaporized. The hypothesis is advanced about an exothermal interaction of Pd vapor with graphite. The variations of atom residence time in the furnace are discussed as practical limitations of the theory of absolute analysis.

Rapid and sensitive determination of radiocesium (Cs-135, Cs-137) in the presence of excess barium by electrothermal vaporization-inductively coupled plasma-mass spectrometry (ETV-ICP-MS) with potassium thiocyanate as modifier.

An electrothermal vaporization-inductively coupled plasma-mass spectrometric (ETV-ICP-MS) method based on selective volatilization of cesium with KSCN as modifier has been developed for determination of radiocesium, i.e. 135Cs and 137Cs, in the presence of isobaric barium. A 10,000 times excess of barium, which was volatilized at a temperature of 1,100 degrees C, resulted only in a 1% signal increase in the signal of mass 135 amu. The recommended concentration of KSCN is 0.3 mM, and pretreatment and volatilization temperatures are 400 degrees C and 1,100 degrees C, respectively. A ramp time of 1 s is recommeded for the volatilization step. The achieved limit of detection for 135Cs is 0.2 pg/mL (10 microBq/mL) and 4 fg (0.2 microBq) absolute for a sample volume of 20 microL. This means a limit of detection for 137Cs of 0.2 pg/mL (0.6 Bq/mL) and of 4 fg (0.01 Bq) absolute. Signal variations of 135Cs and 137Cs, respectively, in spiked samples with various matrices were investigated.

Influence of methodological parameters on human jaw-stretch reflexes.

The influence of methodological parameters and experimental conditions on the human jaw-stretch reflex was studied in healthy subjects in order to develop a reliable tool for investigation of the excitability of motoneuron pool. Short-latency excitatory reflex responses were evoked by a custom-made stretch device with the subjects biting on a jaw-bar with their front teeth. The displacement and ramp time of the stretches were accurately controlled and automatically triggered by a computer. The reflex responses were measured in the surface electromyogram (EMG) of the masseter and anterior temporalis muscles with online monitoring of the clenching level. The peak-to-peak amplitude of the jaw-stretch reflex was shown to be proportional to the level of EMG activity during isometric contractions, to increase proportionally with increasing stretch displacement at a given ramp time, and to decrease proportionally with increasing ramp time at a given stretch displacement. There were no significant differences in the reflex amplitude between repeated recordings within one session or between different sessions. Local anesthetic around the lower incisors as well as the upper incisors had no significant influence on the reflex amplitude. However, different biting positions on the bars of the stretch device significantly influenced the amplitude of the stretch reflex.

Excitatory actions of experimental muscle pain on early and late components of human jaw stretch reflexes

It has recently been shown that a slow stretch evokes a short-latency (probably monosynaptic) and a long-latency (polysynaptic) reflex response in human jaw-closing muscles. The effect of nociceptive muscle input on the fusimotor system has not been investigated in detail. In order to investigate the effect of sustained muscle pain on the jaw stretch reflex, two main experiments were performed. Stretch reflex responses were evoked in the masseter and temporalis muscles by slow stretches (1-mm displacement, 40-ms ramp time) before, during and 15 min after a period of experimentally induced muscle pain. In experiment I, a dose of 1.0 M hypertonic or 154 mM isotonic (control) saline was infused in random order into the left masseter for up to 15 min ( n=12). The level of excitation of the left masseter at 15% maximal voluntary contraction was controlled by visual feedback of the surface EMG (sEMG). In experiment II, a dose of 1.0 M saline was infused into the left masseter but with feedback from the sEMG of the right masseter ( n=12). In a control experiment, both sEMG and intramuscular EMG (imEMG) were recorded from the left and right masseters; the feedback was from imEMG of the left masseter ( n=12). The early (onset: 9–10 ms) and late (duration from 25 to 40 ms) reflex components were recorded and analysed in all experiments. Infusion of 1.0 M saline caused moderate pain (mean score on a Visual Analogue Pain Scale: 4.9–5.0 cm). The peak-to-peak amplitude of the early reflex component in the painful masseter normalized to the pre-stimulus EMG activity was significantly higher during the pain than the pre- and post-infusion conditions in all experiments. The normalized area of the late reflex component in the painful masseter was significantly larger than in the pre-infusion condition in all experiments. Isotonic saline had no significant effect on the jaw stretch reflexes. These results indicate that experimental jaw-muscle pain in humans facilitates the early as well as the late component of the jaw stretch reflex response as revealed by both sEMG and imEMG. This effect appears to be independent of the level of excitation of the muscle and not related to volume effects of the injected saline. A change in the sensitivity of the fusimotor system during muscle pain is suggested as an explanation.