Effects of Hermetic Storage on Adult Sitophilus oryzae L. (Coleoptera: Curculionidae) Acoustic Activity Patterns and Mortality.

Hermetic storage is of interest to farmers and warehouse managers as a method to control insect pests in small storage facilities. To develop improved understanding of effects of hermetic storage on insect pest activity and mortality over time, oxygen levels, acoustic signals, and observations of visual movement were recorded from replicates of 25, 50, and 100 adult Sitophilus oryzae (L.) (Coleoptera: Curculionidae) hermetically sealed in 500- and 1,000-ml glass jars. Recordings were done for 28 d; twice daily for the first 6 d and twice weekly thereafter. Insect sounds were analyzed as short bursts (trains) of impulses with spectra that matched average spectra (profiles) of previously verified insect sound impulses. Oxygen consumption was highest in treatments of 100 insects/500-ml jar and lowest in 25/1000-ml jars. The rates of bursts per insect, number of impulses per burst, and rates of burst impulses per insect decreased as the residual oxygen levels decreased in each treatment. Activity rates <0.02 bursts s-1, the acoustic detection threshold, typically occurred as oxygen fell below 5%. Mortality was observed at 2% levels. The time to obtain these levels of insect activity and oxygen depletion ranged from 3-14 d depending on initial infestation levels. Acoustic detection made it possible to estimate the duration required for reduction of insect activity to levels resulting in negligible damage to the stored product under hermetic conditions. Such information is of value to farmers and warehouse managers attempting to reduce pest damage in stored crops.

Combined effects of Hurricane Katrina and Hurricane Gustav on the mental health of mothers of small children.

Few studies have assessed the results of multiple exposures to disaster. Our objective was to examine the effect of experiencing Hurricane Gustav on mental health of women previously exposed to Hurricane Katrina. A total of 102 women from Southern Louisiana were interviewed by telephone. Experience of the hurricanes was assessed with questions about injury, danger and damage, while depression was assessed with the Edinburgh Depression Scale and post-traumatic stress disorder using the Post-Traumatic Checklist. Minor stressors, social support, trait resilience and perceived benefit had been measured previously. Mental health was examined with linear and log-linear models. Women who had a severe experience of both Gustav and Katrina scored higher on the mental health scales, but finding new ways to cope after Katrina or feeling more prepared was not protective. About half the population had better mental health scores after Gustav than at previous measures. Improvement was more likely among those who reported high social support or low levels of minor stressors, or were younger. Trait resilience mitigated the effect of hurricane exposure. Multiple disaster experiences are associated with worse mental health overall, although many women are resilient. Perceiving benefit after the first disaster was not protective.

A study of ablation, spatial, and temporal characteristics of laser-induced plasmas generated by multiple collinear pulses.

Multi-pulse laser-induced breakdown spectroscopy (LIBS) in the collinear pulse configuration with time-integrating detection was performed on metallic samples in ambient air in an effort to clarify the contributing processes responsible for the signal enhancement observed in comparison with single-pulse excitation. Complementary experiments were also carried out on another LIBS setup using detection by an imaging spectrograph with high time resolution. The effects of laser bursts consisting of up to seven ns-range pulses from Nd-doped solid-state lasers operating at their fundamental wavelength and separated by 8.5-50 micros time gaps was studied. The ablation and emission characteristics of the generated plasmas were investigated using light profilometry, microscopy, plasma imaging, emission distribution mapping, time-resolved line emission monitoring, and plasma temperature calculations. The experimental data suggest that the two contributing processes mainly responsible for the signal enhancement effect are the plume reheating caused by the sequential laser pulses and, more dominantly, the increased material ablation attributed to the lower breakdown threshold for the preheated (molten) sample surface and/or the reduced background gas pressure behind the shockwave of preceding pulses.

Model-based identification of PEEP titrations during different volemic levels.

A cardiovascular system (CVS) model has previously been validated in simulated cardiac and circulatory disease states. It has also been shown to accurately capture all main hemodynamic trends in a porcine model of pulmonary embolism. In this research, a slightly extended CVS model and parameter identification process are presented and validated in a porcine experiment of positive end-expiratory pressure (PEEP) titrations at different volemic levels. The model is extended to more physiologically represent the separation of venous and arterial circulation. Errors for the identified model are within 5% when re-simulated and compared to clinical data. All identified parameter trends match clinically expected changes. This work represents another clinical validation of the underlying fundamental CVS model, and the methods and approach of using them for cardiovascular diagnosis in critical care.

Prediction of hemodynamic changes towards PEEP titrations at different volemic levels using a minimal cardiovascular model.

A cardiovascular system model and parameter identification method have previously been validated for porcine experiments of induced pulmonary embolism and positive end-expiratory pressure (PEEP) titrations, accurately tracking all the main hemodynamic trends. In this research, the model and parameter identification process are further validated by predicting the effect of intervention. An overall population-specific rule linking specific model parameters to increases in PEEP is formulated to predict the hemodynamic effects on arterial pressure, pulmonary artery pressure and stroke volume. Hemodynamic changes are predicted for an increase from 0 to 10 cm H(2)O with median absolute percentage errors less than 7% (systolic pressures) and 13% (stroke volume). For an increase from 10 to 20 cm H(2)O median absolute percentage errors are less than 11% (systolic pressures) and 17% (stroke volume). These results validate the general applicability of such a rule, which is not pig-specific, but holds over for all analyzed pigs. This rule enables physiological simulation and prediction of patient response. Overall, the prediction accuracy achieved represents a further clinical validation of these models, methods and overall approach to cardiovascular diagnosis and therapy guidance.

Laser induced breakdown spectroscopy as a tool for discrimination of glass for forensic applications.

Materials analysis and characterization can provide important information as evidence in legal proceedings. The potential of laser induced breakdown spectroscopy (LIBS) for the discrimination of glass fragments for forensic applications is presented here. The proposed method is based on the fact that glass materials can be characterized by their unique spectral fingerprint. Taking advantage of the multielement detection capability and minimal to no sample preparation of LIBS, we compared glass spectra from car windows using linear and rank correlation methods. Linear correlation combined with the use of a spectral mask, which eliminates some high-intensity emission lines from the major elements present in glass, provides effective identification and discrimination at a 95% confidence level.

Lifetime measurements of several S, P, and D states of thallium in a glow discharge by single-step and two-step laser-excited fluorescence.

The lifetimes of several states in a thallium see-through hollow cathode discharge, or galvatron, are obtained to characterize its potential as an atomic line filter. The lifetimes of the thallium 6(2)D(3/2), 6(2)D(5/2), and 7(2)S(1/2) states are measured by time-resolved single-step laser-excited fluorescence by use of a 276.787 nm laser pulse or a 535.046 nm laser pulse and measuring the resulting fluorescence waveform at the appropriate wavelength. Values of 6.4 +/- 0.1, 7.5 +/- 1.1, and 7.7 +/- 0.2 ns were obtained for the 6(2)D(3/2), 6(2)D(5/2), and 7(2)S(1/2) states, respectively, which agree with values obtained by previous authors, as well as calculated values. No current dependence was observed for each of these states. The lifetime of the long-lived thallium 6(2)P(3/2) degrees metastable state was measured by two-step laser-excited fluorescence at various applied currents. The metastable level was pumped by a 276.787 nm laser pulse, and a temporally delayed 535.046 nm laser pulse interrogated the population of the metastable state. Relating the fluorescence intensity to the population of the metastable state as a function of delay time yielded a decay curve for the 6(2)P(3/2) degrees metastable state. Values of 2.1 +/- 0.2, 2.8 +/- 0.1, 3.1 +/- 0.3, 3.8 +/- 0.4, and 4.8 +/- 0.6 micros were found for applied currents of 14.0, 12.0, 10.0, 8.0, and 6.0 mA, respectively. The resulting lifetimes for the 6(2)P(3/2) degrees metastable state clearly show a dependence on the applied current and are expected to be due to collisions with the wall of the cathode, as well as a contribution due to collisions with electrons.

The application of microbore UPLC/oa-TOF-MS and 1H NMR spectroscopy to the metabonomic analysis of rat urine following the intravenous administration of pravastatin.

The metabonomic effects of hepatotoxic doses of pravastatin on the urinary metabolic profiles of female rats have been investigated using ultra performance liquid chromatography (UPLC)-oa-TOF-MS and, independently, by (1)H NMR spectroscopy. UPLC was performed using a 1 mm microbore column packed with 1.7 microm particles. Examination of the data obtained from the individual animals, aided by statistical interpretation of the data, made it possible to identify potential markers for toxicological effects, with both NMR and UPLC-MS analysis highlighting distinct changes in the urinary metabolite profiles. These markers, which included elevated taurine and creatine, as well as bile acids, were consistent with hepatotoxicity in some animals, and this hypothesis was supported by histopathological and clinical chemistry findings. The analytical data from both techniques could be used to define a metabolic "trajectory" as toxicity developed and to provide an explanation for the lack of hepatotoxicity for one of the animals. The two analytical approaches (UPLC-MS and NMR) were found to be complementary whilst the use of a 1mm i.d. x 100 mm column reduced the amount of sample required for analysis to 2 microL, compared with 10 microL for a 2.1mm i.d. x 100 mm column. The 1mm i.d. column also provided increased signal-to-noise without loss of chromatographic efficiency.

An automated method for measuring static pressure-volume curves of the respiratory system and its application in healthy lungs and after lung damage by oleic acid infusion.

Elastic pressure/volume (PV) curves of the respiratory system have attracted increasing interest, because they may be helpful to optimize ventilator settings in patients undergoing mechanical ventilation. Clinically applicable methods need to be fast, use routinely available equipment, draw the inspiratory and expiratory PV curve limbs, separate the resistive and viscoelastic properties of the respiratory system from the elastic properties, and provide reproducible measurements. This paper presents a computer-controlled method for rapid measurements of static PV curves using a long inflation-deflation with pauses, and its evaluation in six pigs before and after lung damage caused by oleic acid. The method is fast, i.e. 20.5 +/- 1.9 s (mean +/- SD) in healthy lungs and 17.7 +/- 4.1 s in diseased lungs, this including inspiratory and expiratory pauses of 1.1 s duration. In addition the only equipment used was a clinical ventilator and a PC. For healthy and damaged lungs expiratory PV curve limbs were very reproducible and were at higher volume than the inspiratory limbs, indicating hysteresis. For damaged lungs inspiratory PV limbs were reproducible. For healthy lungs the inspiratory limbs were reproducible but only after the first inflation-deflation. It is possible that during the first inflation alveoli are recruited which are not derecruited on deflation, shifting the inspiratory limb of the PV curve. The paused long inflation-deflation technique provides a quick, automated measurement of static PV curves on both inspiratory and expiratory limbs using routinely available equipment in the intensive care unit.

Modulation of emotion by cognition and cognition by emotion.

In this study, we examined the impact of goal-directed processing on the response to emotional pictures and the impact of emotional pictures on goal-directed processing. Subjects (N=22) viewed neutral or emotional pictures in the presence or absence of a demanding cognitive task. Goal-directed processing disrupted the BOLD response to emotional pictures. In particular, the BOLD response within bilateral amygdala and inferior frontal gyrus decreased during concurrent task performance. Moreover, the presence of both positive and negative distractors disrupted task performance, with reaction times increasing for emotional relative to neutral distractors. Moreover, in line with the suggestion of the importance of lateral frontal regions in emotional regulation [Ochsner, K. N., Ray, R. D., Cooper, J. C., Robertson, E. R., Chopra, S., Gabrieli, J. D., et al. (2004). For better or for worse: neural systems supporting the cognitive down-and up-regulation of negative emotion. NeuroImage, 23(2), 483-499], connectivity analysis revealed positive connectivity between lateral superior frontal cortex and regions of middle frontal cortex previously implicated in emotional suppression [Beauregard, M., Levesque, J., and Bourgouin, P. (2001). Neural correlates of conscious self-regulation of emotion. J. Neurosci., 21 (18), RC165.; Levesque, J., Eugene, F., Joanette, Y., Paquette, V., Mensour, B., Beaudoin, G., et al. (2003). Neural circuitry underlying voluntary suppression of sadness. Biol. Psychiatry, 53 (6), 502-510.; Ohira, H., Nomura, M., Ichikawa, N., Isowa, T., Iidaka, T., Sato, A., et al. (2006). Association of neural and physiological responses during voluntary emotion suppression. NeuroImage, 29 (3), 721-733] and negative connectivity with bilateral amygdala. These data suggest that processes involved in emotional regulation are recruited during task performance in the context of emotional distractors.

Stability of silver colloids as substrate for surface enhanced Raman spectroscopy detection of dipicolinic acid.

Silver colloids have been commonly used as substrates for surface enhanced Raman spectroscopy (SERS). It has been shown that SERS requires partial aggregation of the silver colloids. This study evaluates factors affecting the aggregative state of the silver colloids such as the age of the silver colloids and the aggregation as a result of addition of the analyte. The silver colloids are obtained from the chemical reduction of silver nitrate by sodium borohydride. Further oxidation of the sodium borohydride solution at room temperature results in concentration changes of the resulting silver colloids. Methods of controlling the sodium borohydride depletion are presented in this paper. The analyte used is dipicolinic acid, a molecular signature of Bacillus spores.

Using physiological models and decision theory for selecting appropriate ventilator settings.

OBJECTIVE: To present a decision support system for optimising mechanical ventilation in patients residing in the intensive care unit. METHODS: Mathematical models of oxygen transport, carbon dioxide transport and lung mechanics are combined with penalty functions describing clinical preference toward the goals and side-effects of mechanical ventilation in a decision theoretic approach. Penalties are quantified for risk of lung barotrauma, acidosis or alkalosis, oxygen toxicity or absorption atelectasis, and hypoxaemia. RESULTS: The system is presented with an example of its use in a post-surgical patient. The mathematical models describe the patient's data, and the system suggests an optimal ventilator strategy in line with clinical practice. CONCLUSIONS: The system illustrates how mathematical models combined with decision theory can aid in the difficult compromises necessary when deciding on ventilator settings.

Radiative model of post-breakdown laser-induced plasma expanding into ambient gas.

The dynamics of the radiative plasma expansion into an ambient gas is considered. The model describes the evolution of the plasma emission spectrum and the dynamics of the resulting shock wave. The time frame for the applicability of the model is in the tens of nanoseconds after the laser pulse is terminated, until a few microseconds later when the plasma ceases to emit. It is assumed that local thermodynamic equilibrium is established and that the plume expands with spherical symmetry. The model outputs are spatial and temporal distributions of atoms, ions, and electron number densities, evolution of atom and ion line profiles, and the shock wave. The model should be applicable to spectroscopic analysis of the initial plasma state and plasma dynamics.

Determination of the maximum temperature at the center of an optically thick laser-induced plasma using self-reversed spectral lines.

A method of temperature measurement based on the model developed by Bartels of an optically thick inhomogeneous plasma was applied to a laser plasma induced on a target containing barium. The method involves the intensity ratio measurement of two self-reversed Ba(II) lines. The temperature thus determined corresponds to the maximum temperature in the plasma center. The plasma temperature was measured for delay times between 0.5 micros and 10 micros in two spectrometer operating modes: the scanning mode and the dual-wavelength mode, the latter resulting in better precision. A detailed analysis of experimental errors was performed. The error strongly depended on the wavelength separation of the lines used. The most accurate results were obtained for the largest line separation. Using one line in the UV and the other in the visible region, the relative error was 2-6% for temperatures between 8000 K and 20 000 K. The distribution of the plasma temperature along the plasma height was measured in the same delay time range. The temperature was found to be uniform along the plasma vertical axis, thus confirming the plasma cylindrical symmetry.

Microchip laser-induced breakdown spectroscopy: a preliminary feasibility investigation.

A commercial, 7 microJ/pulse, 550 ps microchip laser is used to induce plasma on Pb, Si, Cu, Fe, Ni, Ti, Zn, Ta, and Mo foils and a Si wafer. The measured plasma lifetime is comparable with the duration of the laser pulse (a few ns). The plasma continuum radiation is low, while some of the strong resonance lines (e.g., Zn 213.86 nm) show self-reversal. Quantitative analysis is possible using non-gated detectors but analytical lines should be chosen with care to avoid reduction in the linear dynamic range. The mass removed (0.5-20 ng/pulse) is sufficient to yield spectra that are detectable with portable grating spectrometers equipped with non-gated, non-intensified detector arrays. The spectrum of Cd is detected with a broadband portable spectrometer (200-950 nm). The combination of the broadband spectrometer and the microchip laser is very promising for material identification, especially in field applications.

High-resolution two-grating spectrometer for dual wavelength spectral imaging.

A two-grating high-resolution spectrometer for dual wavelength imaging is demonstrated based on the standard Czerny-Turner mounting with an auxiliary grating and a mirror. A two-dimensional charge-coupled device (CCD) detector in the spectrometer focal plane allows simultaneous detection of two spectral intervals. Each spectrometer grating is driven by a high-precision stepper motor interfaced to a computer via home-made software. The software allows fast tuning of the gratings to a desirable spectral interval anywhere between 200 nm and 800 nm. The spectral interval widths are 2-3 nm for a ''high-resolution'' (2400 grooves/mm) grating and 4-5 nm for a ''low-resolution'' (1200 grooves/mm) grating. The resolution varies between 0.01 nm and 0.02 nm depending on the grating used. The performance of the spectrometer is demonstrated by detecting spectrally resolved images from a back-illuminated template and from a laser-induced plasma. The spectrometer can be useful for two-line spectroscopic diagnostics or can be expanded for multi-element spectral analysis.

Identification of patient specific parameters for a minimal cardiac model.

A minimal cardiac model has been developed which accurately captures the essential dynamics of the cardiovascular system (CVS). This paper develops an integral based parameter identification method for fast and accurate identification of patient specific parameters for this minimal model. The integral method is implemented using a single chamber model to prove the concept, and turns a previously nonlinear and nonconvex optimization problem into a linear and convex problem. The method can be readily extended to the full minimal cardiac model and enables rapid identification of model parameters to match a particular patient condition in clinical real time (3-5 minutes). This information can then be used to assist medical staff in understanding, diagnosis and treatment selection.

Computationally efficient velocity profile solutions for cardiac haemodynamics.

This work reformulates the nonlinear differential equations associated with time varying resistance in minimal cardio-vascular system models into a system of linear equations with an analytical solution. The importance of including time varying resistance is shown for a single chamber model where there is a 17.5% difference in cardiac output when compared with a constant resistance model. However, the increased complexity has significant extra computational cost. This new formulation provides a significant computational saving of 15x over the previous method. This improvement enables more physiological accuracy with minimal cost in computational time. As a result, the model can be used in clinical situations to aid diagnosis and therapy selection without compromising on physiological accuracy.

Laser-enhanced ionization with avalanche amplification: detection of cesium at fg/mL levels.

The avalanche amplification of the laser-enhanced ionization signal of Cs atoms in a flame has been studied. Ionization of Cs atoms, enhanced by two-step excitation, was detected in hydrogen and propane flames. By employing the effect of avalanche amplification of electrons, high signal-to-noise ratio (approximately 10(4)) was obtained for a 100 ppt Cs solution. The extrapolated limit of detection was 30 fg/mL (ppq).