Indoor Air Inhalation Risk Assessment for Volatiles Emanating from Light Nonaqueous Phase Liquids

The indoor air inhalation pathway for volatile contaminants in soil and groundwater has received much attention recently. The risk of exposure may be higher when volatile organic compounds (VOCs) reside as constituents of a free product plume below residential or commercial structures than when dissolved in groundwater or adsorbed on soil. A methodology was developed for assessing the potential for vapor phase migration—and associated risk of indoor air inhalation—of volatile constituents from a light nonaqueous phase liquid (LNAPL) plume on top of the water table. The potential risk from inhalation of VOCs in indoor air emanating from a subsurface Jet Fuel 4 (JP-4) plume by hypothetical residential receptors was assessed at a site. Chemicals of concern (COCs) were identified and evaluated using data from the composition of JP-4 mixtures and published chemical, physical, and toxicological data. The method estimates the equilibrium vapor concentrations of JP-4 constituents using Raoult's Law for partial vapor pressure of mixtures based on assumptions about the mixture composition of JP-4. The maximum allowable vapor concentration at the source (immediately above the LNAPL) corresponding to an indoor air target concentration based on acceptable risk levels are calculated using the Johnson and Ettinger model. The model calculates the attenuation factor caused by the migration of the vapor phase VOCs through the soil column above the JP-4 plume and through subsurface foundation slabs. Finally, the maximum allowable soil gas concentrations above the LNAPL for individual constituents were calculated using this methodology and compared to the calculated equilibrium vapor concentrations of each COC to assess the likelihood of potential risk from the indoor air inhalation pathway.     

Cellulose/water: liquid/gas and liquid/liquid phase equilibria and their consistent modeling

Liquid/liquid and liquid/gas equilibria were measured for the water/cellulose system at 80 degrees C using three different polymer samples. For these experiments we prepared cellulose films of approximately 20-25 microm in thickness and determined their equilibrium swelling in water. Thereafter the polymer concentration in the mixed phase was increased by means of a stepwise removal of the volatile component, and the equilibrium vapor pressures were measured using an automated combination of head space sampling and gas chromatography. Contrary to the usual behavior of polymers, the swelling of cellulose increases as its molar mass becomes larger. The Flory-Huggins interaction parameters calculated from the measured vapor pressures pass a pronounced minimum as a function of composition; for high cellulose contents they are negative, whereas they become positive for water-rich mixtures. All experimental findings are consistently interpreted by means of an approach accounting explicitly for the effects of chain connectivity and for the ability of macromolecules to respond to environmental changes by conformational rearrangement.     

A numerical study of the shape of the surface separating flow into branches in microvascular bifurcations.

The shape of the separating surface formed by the streamlines entering the branches of microvascular bifurcations plays a major role in determining the distribution of red blood cells and other blood constituents downstream from the bifurcation. Using the finite element method, we determined the shape of the surface through numerical solution of three dimensional Navier-Stokes equations for fluid flow at low Reynolds numbers in a T-type bifurcation of circular tubes. Calculations were done for a wide range of daughter branch to parent vessel diameter ratios and flow ratios. The effect of Reynolds number was also studied. Our numerical results are in good agreement with previously reported experimental data of Rong and Carr (Microvascular Research, Vol. 39, pp. 186-202, 1990). The numerical results of this study will be used to predict the concentration of blood constituents downstream from microvascular bifurcations providing that the inlet concentration profile is known.     

Sterilization-in-place of concentrated nutrient solutions

Sterilization-in-place (batch sterilization) behavior of concentrated nutrient solutions was quantified for various nutrient solutions of fermentation processing interest. Experimental observations of sterilization temperatures and corresponding pressures suggested that sterilization pressures were substantially lower for concentrated nutrient solutions than for water. This effect was believed to be directly related to the lower vapor pressure and lower activity coefficient of these concentrated nutrient solutions. Using thermodynamic data for the specific nutrient, pressures and temperatures, calculated as a function of nutrient concentration, compared favorably with observed values. This method permits estimation of the expected sterilization pressure for concentrated nutrients for which no experimental observations have yet been made at the sterilization temperature of interest. Estimate accuracy, ranging from 0.006 to 0.06 bar, can be enhanced if one set of experimental temperature/pressure values is known at the expected sterilization scale. The potential impact of the nature of concentrated nutrient solutions on steam-in-place vessel headspace temperature distributions, D-values of B. stearothermophilus, and overall sterilization effectiveness is also discussed. The low vapor pressure of concentrated nutrient solutions was hypothesized to directly impact air removal effectiveness and sterilization performance during batch sterilization. Copyright 1999 John Wiley & Sons, Inc.     

Mechanical analysis of heterogeneous, atherosclerotic human aorta.

An experimental technique was developed to determine the finite strain field in heterogeneous, diseased human aortic cross sections at physiologic pressures in vitro. Also, the distributions within the cross sections of four histologic features (disease-free zones, lipid accumulations, fibrous intimal tissue, and regions of calcification) were quantified using light microscopic morphometry. A model incorporating heterogeneous, plane stress finite elements coupled the experimental and histologic data. Tissue constituent mechanical properties were determined through an optimization strategy, and the distributions of stress and strain energy in the diseased vascular wall were calculated. Results show that the constituents of atherosclerotic lesions exhibit large differences in their bilinear mechanical properties. The distributions of stress and strain energy in the diseased vascular wall are strongly influenced by both lesion structure and composition. These results suggest that accounting for heterogeneities in the mechanical analysis of atherosclerotic arterial tissue is critical to establishing links between lesion morphology and the susceptibility of plaque to mechanical disruption in vivo.     

Modeling and measurements of solid-liquid and vapor-liquid equilibria of polyols and carbohydrates in aqueous solution

The solubilities of five saccharides in water have been measured at various temperatures. This includes the monosaccharides xylose and galactose, and the disaccharides maltose monohydrate, cellobiose and trehalose dihydrate. A method that uses interaction energies and interaction parameters calculated with molecular mechanics methods has shown to give good predictions of the phase behavior of a variety of mixtures, including glycols and small saccharides in aqueous solution. The method is completely predictive, as the strength of the molecular interactions is determined with a theoretical method in the absence of any phase equilibrium data. For calculating solubilities, experimental values for the melting points and the heats of fusion of the compounds under study are, however, necessary. The solubilities of the five saccharides listed above, raffinose and meso-erythritol in water were calculated with this method. The calculated solubilities are in reasonably good agreement with experiment, and in the case of meso-erythritol, which is a polyalcohol (polyol), and galactose, the agreement between prediction and experiment is excellent. Also the vapor pressures of water over several polyols and saccharides in aqueous solution have been predicted with this method, giving results in excellent agreement with the experimental values.     

Radiation pressure on a biconcave human Red Blood Cell and the resulting deformation in a pair of parallel optical traps

We calculated the three‐dimensional optical stress distribution and the resulting deformation on a biconcave human red blood cell (RBC) in a pair of parallel optical trap. We assumed a Gaussian intensity distribution with a spherical wavefront for each trapping beam and calculated the optical stress from the momentum transfer associated with the reflection and refraction of the incident photons at each interface. The RBC was modelled as a biconcave thin elastic membrane with uniform elasticity and a uniform thickness of 0.25 μm. The resulting cell deformation was determined from the optical stress distribution by finite element software, Comsol Structure Mechanics Module, with Young's modulus (E) as a fitting parameter in order to fit the theoretical results for cell elongation to our experimental data. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of water vapor pressure on the thermal decomposition of 2-chloroethylphosphonic Acid

Decomposition of 2-chloroethylphosphonic acid (Ethephon) was studied in dried films at various water vapor pressures (0.6 to 86.9 millimeters Hg, 3.2 to 93.9% relative humidity) and temperatures (20, 30, 40, and 50 C) at pH 6.3 and 7.0. The rate of decomposition could be determined equally well by [¹⁴C]Ethephon or ethylene measurements. The rate increases at increasing water vapor pressures at a constant temperature and pH, up to an optimum. The optimum vapor pressure for decomposition approximately doubles for each 10 C increase. The activation energy for the decomposition reaction in water vapor pressures of 3.2 to 12 millimeters Hg is 8.7 and 14.3 kilocalories per mole at pH 6.3 and 7.0, respectively.     

Cardiopulmonary reference standards in the pregnant sheep (Ovis aries): a comparative study of ovine and human physiology in obstetrics.

1. Complete blood counts, respiratory rate, tidal volume, arterial and mixed venous blood gases; heart rate, cardiac output, and arterial, pulmonary artery, central venous and pulmonary wedge pressures were determined in 10 pregnant adult sheep of 42.7-65.7 kg body weight. 2. Arithmetic means, standard deviations, and coefficients of variation were calculated to develop reference values; in addition, the 95% confidence limits for ranges were established. 3. Comparison of derived data with that from non-pregnant sheep shows changes similar to those seen when examining pregnant and non-pregnant humans. 4. These results indicate the pregnant sheep is an acceptable model for human obstetrical research.     

Experiences with a sac-type artificial heart

A total replacement artificial heart is described having in vitro performance satisfying human requirements up to and including moderate work.The in vitro design has been modified to make its implantation into the chests of experimental animals technically feasible.The heart has been tested in vivo for up to six hours, and has been found to provide the experimental animals with adequate blood flow and pressures.Preliminary tests have shown major problems of air embolism and red blood cell hemolysis.The heart design and technique of implantation are undergoing further improvement. Performance will be more comprehensively examined with the use of larger experimental animals in order more accurately to evaluate the heart''s potential.     

仙人掌超微粉挥发性成分研究

目的：研究仙人掌中的挥发性成分。方法：利用水蒸气蒸馏法提取经超微粉碎后的仙人掌[Opuntia dillenii（Ker-Gaw.）Haw]挥发油,用GC-MS进行测定,结合计算机检索技术对分离的化合物进行结构鉴定,应用色谱峰面积归一化法计算各成分的相对百分含量。结果：共分离鉴定出32个化学成分,占总成分的98.097%,其中相对百分含量大于2%的分别确定为异丁基邻苯二甲酸酯（Isobutyl phthalate）27.492%,棕榈酸（Palmitic acid）16.716%,丁基邻苯二甲酸酯（Butyl phthalate）11.257%,薄荷脑（Menthol）6.722%,亚油酸（Linoleic acid）5.995%,壬醛（Nonanal）4.594%,乙醛（Hexanal）3.614%,十二酸（Dodecanic acid）3.244%。结论：通过对仙人掌超微粉挥发性成分的分析鉴定及相对含量测定,为综合利用仙人掌植物资源等提供科学依据。     

Effect of parental flowering and dispersal times on offspring fate in Daucus carota (Apiaceae)

Seeds collected from parents that flowered at different times were dispersed onto experimental plots at different times during the normal dispersal season. Parental flowering and dispersal times, which are correlated with each other, independently affected offspring germination, growth, and time of reproduction. Estimated population growth rates were highest for offspring that were dispersed early in the dispersal season and that came from early flowering parents. The data provide evidence that 1) an individual's fate is determined by the environment of the previous generation, and that 2) an individual's fitness should be calculated from life history data that span more than one generation.     

海南龙血树WD40转录因子基因DcWD40-1的克隆和表达分析

海南龙血树是国产血竭的主要基源植物,其血竭主要化学成分为类黄酮化合物。为进一步了解DcWD40-1在类黄酮生物合成中的潜在功能和作用机制,该研究根据海南龙血树转录组数据,利用RT-PCR技术在海南龙血树中克隆了一个WD40基因DcWD40-1,该基因全长1 550 bp,包含一个1 353 bp的开放阅读框,编码450个氨基酸,蛋白质分子量50.77 kD,理论等电点5.71。生物信息学分析显示,DcWD40-1属于WD40蛋白家族成员,具有5个保守的WD40结构域,和其他植物WD40蛋白同源性高,保守性强。利用Genome Walking方法分离了1 503 bp的DcWD40-1启动子序列,该区域具有典型真核生物启动子结构特征,并含有多个应答激素和胁迫的响应元件。表达分析显示,血竭诱导剂能够诱导Dc WD40-1的表达,DcWD40-1的变化与血竭形成及类黄酮积累正相关。此外,DcWD40-1也能对茉莉酸甲酯、细胞分裂素、油菜素内酯和UV-B处理做出积极响应。     

Imaging coronary artery microstructure using second-harmonic and two-photon fluorescence microscopy

The microstructural basis for the mechanical properties of blood vessels has not been directly determined because of the lack of a nondestructive method that yields a three-dimensional view of these vascular wall constituents. Here, we demonstrate that multiphoton microscopy can be used to visualize the microstructural basis of blood vessel mechanical properties, by combining mechanical testing (distension) of excised porcine coronary arteries with simultaneous two-photon excited fluorescence and second-harmonic generation microscopy. Our results show that second-harmonic generation signals derived from collagen can be spectrally isolated from elastin and smooth muscle cell two-photon fluorescence. Two-photon fluorescence signals can be further characterized by emission maxima at 495 nm and 520 nm, corresponding to elastin and cellular contributions, respectively. Two-dimensional reconstructions of spectrally fused images permit high-resolution visualization of collagen and elastin fibrils and smooth muscle cells from intima to adventitia. These structural features are confirmed by coregistration of multiphoton microscopy images with conventional histology. Significant changes in mean fibril thickness and overall wall dimension were observed when comparing no load (zero transmural pressure) and zero-stress conditions to 30 and 180 mmHg distension pressures. Overall, these data suggest that multiphoton microscopy is a highly sensitive and promising technique for studying the morphometric properties of the microstructure of the blood vessel wall.     

Single and Multicomponent Gas Phase Diffusion in a Porous Media: Modeling and Laboratory Measurements

Subsurface vapor migration of volatile chemicals may impact ambient and indoor air quality, increasing the importance to investigate the fate and transport of these chemicals. This project involved both modeling and experimental work to study the vapor phase transport behavior of single, binary, and tertiary component systems present in the gas phase. The experimental phase resulted in the development of a diffusion cell for measuring vapor phase transport. Three organic compounds (toluene, cumene, and isooctane) common to petroleum-based products were selected. The objective of this research project was to evaluate how the rate of a component diffusing alone in a stagnant gas mixture compares to the rate of the same component when diffusing in the presence of multiple diffusing species. The equipment was first validated by measuring the unobstructed gas phase diffusion fluxes for each organic compound. The diffusion coefficients were then calculated from the experimentally measured diffusive fluxes using Fick's Law at 20 and 25°C and compared to the respective literature values. The experimental/literature (E/L) ratio was calculated for toluene, cumene, and isooctane. The range of the average E/L ratio for the single component data sets is 0.93 to 1.05. The validation data provided the baseline for extending the research to multicomponent data. The multi-component systems research was characterized as either binary systems or a three-component system. The binary systems were either isooctane/tolu-ene or isooctane/cumene. The three-component system consisted of a mixture of all three compounds. For both temperatures and all compounds the flux rate decreased for any single component due to the dilution effect by incorporation into a mixture. Applying Fick's Law to calculate the effective diffusion coefficient for each compound that corresponded to the resulting concentration gradient by the mixture, an enhancement in the diffusive flux of each individual species was observed. This enhancement can be explained by a compositional coupling of each component to all others which results in a total vapor phase mass flux comprised of both diffusive and pseudo-advective mass transport. This pseudo-advective component is attributed to simultaneous diffusion of other species in the presence of the one of interest. Since this research project incorporated a mixture of toluene and cumene present in a background carrier solvent of isooctane, by calculating the ratios Dexp(3-component)/ Dexp(2-component) and Dexp(2-compo-nent)/Dexp(single component), an estimate is obtained of the enhancement effect due to the advective component of simultaneously diffusing chemicals. The diffusivity ratios for the three-component system compared to the dual component system ranged from 0.8 to 3.7. The diffusivity ratios for individual compounds were for 1.5-3.7 cumene, 0.8-1.2 for toluene, and 1.0-1.2 for isooctane. The diffusivity ratios for the dual component system to the single component systems ranged from 0.8 to 4.0. The range of diffusivity ratios for individual compounds were for 2.0-4.0 for cumene, 0.8-1.6 for toluene, and 1.1-1.4 for isooctane. A ratio greater than 1.0 indicated an enhancement effect on the molecular diffusion rate due to the presence of one or more additional diffusing chemical species present. The majority of fate and transport models are based on single component behavior modeled by Fick's Law using the pure gas phase diffusion coefficient. The enhancement of the individual diffusive flux in a multicomponent mixture observed in this study and accounted for by pseudo-advec-tive mass transport results in an under-prediction of the actual multicomponent diffusive fluxes. It is recommended that a more rigorous diffusion equation such as the Stefan-Maxwell equation be considered for incorporation into vapor phase transport models when modeling multicomponent/ contaminant systems.     

Relationship between power law coefficients and major blood constituents affecting the whole blood viscosity

The present work concerns a quantitative analysis of parameters that affect apparent blood viscosity at different low shear rates, i.e, between 1 s⁻¹ and, 100 s⁻¹. Viscosity profile of a large number of blood samples from thromboembolic stroke cases and age and sex matched healthy controls were studied which confirmed non-Newtonian power law behaviour of blood. The power law coefficients,n andk, which are unique to each blood sample, were related with blood viscosity parameters in the form of a mathematical equation by performing non-linear regression analysis. It was possible to calculaten andk of power law model by supplying the values of major blood constituents in the equation obtained for stroke and controls. The calculation ofn andk of a blood sample using the equation obtained, provided a quick information on its apparent viscosity values at any given shear rate without viscometry. The calculated and the experimental viscosity were found in good agreement within a permissible error range. The relation obtained between power law coefficients and major blood constituents in the present investigation would give a quantification of different blood viscosity parameters contributing to the resistance to flow of blood. Such an analysis may be considered as a scientific basis for the study of blood fluidity in different disease conditions.     

Noninvasive measurement of blood pressure in African green monkeys (Cercopithecus aethiops)

Indirect measurements of arterial blood pressure were made in African green monkeys (Cercopithecus aethiops) employing a Doppler ultrasound stethoscope and standard cuff and an Infrasonde automatic blood pressure recorder. Measurements were obtained from anesthetized (10 mg/kg ketamine (HCI) and unanesthetized (1.5 mg/kg ketamine HCI) animals. Ketamine had no significant effect on blood pressure. Indirect measurements from the brachial artery were compared with direct femoral artery measurements and with each other. Systolic blood pressures measured by the Doppler (r = .948) and Infrasonde (r = .920) methods correlated closely with direct measurements but were significantly lower than systolic blood pressures measured by the direct method. Diastolic blood pressures measured by the Infrasonde method agreed closely with direct measurements (r = .947). Systolic blood pressures measured by the indirect methods correlated closely in both anesthetized (r = .973) and unanesthetized (r = .834) animals and were not significantly different. Mean blood pressures calculated from direct and Infrasonde measurements also correlated closely (r = .963), with direct measurements being 4 mmHg higher on the average. Mean blood pressures are less influenced by methodology and are more reproducible than other pressures. These noninvasive methods can be used to obtain simple and accurate measurements of blood pressure from anesthetized and unanesthetized monkeys and are of value in long-term studies in monkeys.     

Changes in oscillometric pulse amplitude envelope with cuff size: implications for blood pressure measurement criteria and cuff size selection

Oscillometric blood pressures are derived from the amplitude envelope of oscillometric pulses generated in an occlusive cuff during cuff inflation or deflation; one factor which will affect the characteristics of these pulses is the size of the cuff bladder. Because limiting values are stipulated in recommendations and standards for bladder sizes, there is a wide variety of acceptable cuff sizes for any particular application. An experimental and theoretical study was undertaken to show the dependence of oscillometric blood pressures on bladder size. Actual cuff-arm compliance data were obtained from two subjects for two cuffs of different bladder size. Theoretical analysis was then applied to the data to predict the effects of different bladder sizes on the characteristics of the pulses. The results show that cuff-arm compliance and bladder size interact to affect the pulse amplitude and hence oscillometric blood pressure determination. These results suggest that blood pressures obtained using the oscillometric method may vary depending on cuff size, and in particular that replacement cuffs for oscillometric non-invasive blood pressure monitors should be chosen carefully.     

Biochemical changes in avian tissues during infection.

Major sources of error in studies of diet--infectious disease interactions relate to failure 1) to define the stage of a disease cycle; and 2) to determine the extent of disease involvement at time of sampling. The former can be determined from clinical and biochemical observations from time of inoculation to recovery or mortality; the latter can be calculated from indexes obtained from histological preparations, changes in body temperatures, and other clinical symptoms, including weight loss and efficiencies of feed utilization. Other significant errors are derived from the normal 24-hour dynamics of particular tissue constituents, which include oscillations and circadian rhythms. Experimental designs and accuracy of data are always helped by prior knowledge of 24-hour patterns of these normal fluctuations. For example, such patterns will reveal that enzyme and hormonal changes are far more dynamic than body water changes. Studies of nutrition--disease interactions are extremely complex and the researcher must be aware of and eliminate as many sources of experimental error as possible to avoid confounding the data.     

Dietary fibre and blood pressure

Ninety-four volunteers participated in a three-day weighed dietary survey and had their blood pressures measured once. They were classified according to their fibre intake. Subjects with a high-fibre intake were found to have lower mean blood pressures than those with a low-fibre intake. Forty-two of the volunteers further participated in a group of experiments. Those eating a high-fibre diet decreased their dietary fibre, and those eating a low-fibre diet increased their dietary fibre. The first group (11 subjects) showed increased mean blood pressures after four weeks of eating the experimental diet. The last group (31 subjects) showed decreased mean blood pressures after four weeks of eating the experimental diet. The 11 subjects consuming the low-fibre experimental diet showed a decrease in mean blood pressure when some of the saturated fat in their diet was replaced by polyunsaturated fat. A similar substitution carried out by 14 of the subjects consuming the high-fibre experimental diet also resulted in decreased mean blood pressure, but this was not statistically significant. Twelve more volunteers, with hypertension, were all found to have low-fibre diets. They consumed a high-fibre diet for a six-week experimental period, but their mean blood pressures did not decrease significantly; individual recordings varied substantially during this period.It is suggested that differences in the type and quantity of dietary fibre and fat may be responsible for the lower mean blood pressures of groups of vegetarians compared with similar groups of non-vegetarians.