Fluid Dynamics of the Open Port Interface for High-Speed Nanoliter Volume Sampling Mass Spectrometry.

The open port interface (OPI) coupled to an atmospheric pressure ion source is used to capture, dilute, focus, and transport nanoliter volume sample droplets for high-speed mass spectrometric analysis. For typical applications, the system has been optimized to achieve 1 Hz nanoliter volume sample transfer rates while simultaneously diluting the sample >1000-fold to minimize sample matrix-induced ionization suppression. Geometric, flow, and dispensing alterations to the system presented here demonstrate that sample transfer rates for the OPI of at least 15 Hz are possible. The fluid dynamic processes that enable sampling rates of 1 Hz and greater are examined in detail by correlating computational fluid dynamics simulations, analytic calculations, experimental data, photographic footage, and reference to the fluid dynamics literature. The resulting models and experimental results provide the rationale underlying the design and tuning of the system as well as information for developing optimized analytical methods. In combination with acoustic droplet dispensing, referred to as acoustic ejection mass spectrometry (AEMS), this system can be considered to be a special case of flow injection analysis with unique features that control the peak width, symmetry, and segregation of the samples transported in a fluid while simultaneously enabling their mixing and dilution with carrier fluids. In addition, conditions are established to prevent direct contact of the sample with a surface enabling, in combination with a contact-free dispenser like acoustic ejection, a dramatic reduction in sample-to-sample carry-over.

How much does nasal cavity morphology matter? Patterns and rates of olfactory airflow in phyllostomid bats.

The morphology of the nasal cavity in mammals with a good sense of smell includes features that are thought to improve olfactory airflow, such as a dorsal conduit that delivers odours quickly to the olfactory mucosa, an enlarged olfactory recess at the back of the airway, and a clear separation of the olfactory and respiratory regions of the nose. The link between these features and having a good sense of smell has been established by functional examinations of a handful of distantly related mammalian species. In this paper, we provide the first detailed examination of olfactory airflow in a group of closely related species that nevertheless vary in their sense of smell. We study six species of phyllostomid bats that have different airway morphologies and foraging ecologies, which have been linked to differences in olfactory ability or reliance. We hypothesize that differences in morphology correlate with differences in the patterns and rates of airflow, which in turn are consistent with dietary differences. To compare species, we make qualitative and quantitative comparisons of the patterns and rates of airflow through the olfactory region during both inhalation and exhalation across the six species. Contrary to our expectations, we find no clear differences among species in either the patterns of airflow through the airway or in rates of flow through the olfactory region. By and large, olfactory airflow seems to be conserved across species, suggesting that morphological differences appear to be driven by other mechanical demands on the snout, such as breathing and feeding. Olfactory ability may depend on other aspects of the system, such as the neurobiological processing of odours that work within the existing morphology imposed by other functional demands on the nasal cavity.

The role of the olfactory recess in olfactory airflow.

The olfactory recess - a blind pocket at the back of the nasal airway - is thought to play an important role in mammalian olfaction by sequestering air outside of the main airstream, thus giving odorants time to re-circulate. Several studies have shown that species with large olfactory recesses tend to have a well-developed sense of smell. However, no study has investigated how the size of the olfactory recess relates to air circulation near the olfactory epithelium. Here we used a computer model of the nasal cavity from a bat (Carollia perspicillata) to test the hypothesis that a larger olfactory recess improves olfactory airflow. We predicted that during inhalation, models with an enlarged olfactory recess would have slower rates of flow through the olfactory region (i.e. the olfactory recess plus airspace around the olfactory epithelium), while during exhalation these models would have little to no flow through the olfactory recess. To test these predictions, we experimentally modified the size of the olfactory recess while holding the rest of the morphology constant. During inhalation, we found that an enlarged olfactory recess resulted in lower rates of flow in the olfactory region. Upon exhalation, air flowed through the olfactory recess at a lower rate in the model with an enlarged olfactory recess. Taken together, these results indicate that an enlarged olfactory recess improves olfactory airflow during both inhalation and exhalation. These findings add to our growing understanding of how the morphology of the nasal cavity may relate to function in this understudied region of the skull.

Evaluation of water treatment plant UV reactor efficiency against Cryptosporidium parvum oocyst infectivity in immunocompetent suckling mice.

AIM: To assess the efficiency of a medium-pressure UV reactor under full-scale water treatment plant (WTP) conditions on the infectivity of Cryptosporidium parvum oocysts in an Naval Medical Research Institute (NMRI) suckling mice infectivity model. METHODS AND RESULTS: Six/seven-day-old mice were administered orally 2-10x10(4)Cryptosporidium parvum oocysts. Compared with nonirradiated oocysts, 40 mJ cm(-2) UV irradiation of ingested oocysts resulted 7 days later in a 3.4-4.0 log10 reduction in the counts of small intestine oocysts, using a fluorescent flow cytometry assay. CONCLUSION: Present data extend to industrial conditions previous observations of the efficiency of UV irradiation against Cryptosporidium parvum oocyst in vivo development. SIGNIFICANCE AND IMPACT OF THE STUDY: Present results suggest that in WTP conditions, a medium-pressure UV reactor is efficient in reducing the infectivity of Cryptosporidium parvum oocysts, one of the most resistant micro-organisms present in environmental waters.

Low-pressure membrane integrity tests for drinking water treatment: A review.

Low-pressure membrane systems, including microfiltration (MF) and ultrafiltration (UF) membranes, are being increasingly used in drinking water treatments due to their high level of pathogen removal. However, the pathogen will pass through the membrane and contaminate the product if the membrane integrity is compromised. Therefore, an effective on-line integrity monitoring method for MF and UF membrane systems is essential to guarantee the regulatory requirements for pathogen removal. A lot of works on low-pressure membrane integrity tests have been conducted by many researchers. This paper provides a literature review about different low-pressure membrane integrity monitoring methods for the drinking water treatment, including direct methods (pressure-based tests, acoustic sensor test, liquid porosimetry, etc.) and indirect methods (particle counting, particle monitoring, turbidity monitoring, surrogate challenge tests). Additionally, some information about the operation of membrane integrity tests is presented here. It can be realized from this review that it remains urgent to develop an alternative on-line detection technique for a quick, accurate, simple, continuous and relatively inexpensive evaluation of low-pressure membrane integrity. To better satisfy regulatory requirements for drinking water treatments, the characteristic of this ideal membrane integrity test is proposed at the end of this paper.

Parasuicide, anhedonia, and depression.

Previous research has shown that anhedonia characterizes suicide attempters. The present study aimed to replicate this finding using the level of depression as a control. Seventy-three depressed parasuicides, 30 nondepressed parasuicides, and 104 matched controls were assessed on the Revised Physical Anhedonia Scale (PAS). Consistent with previous studies, depressed parasuicides were significantly more anhedonic than controls, but nondepressed parasuicides were not significantly more anhedonic than controls. Moreover, multiple linear regression analysis showed that the PAS score explained a negligible part of the variance in the distinction between parasuicides and controls. Anhedonia in parasuicides constitutes a depressive feature and not a temperamental trait.

[Validation of the French version of a pleasure scale for children (The Pleasure Scale for Children, PSC, Kazdin, 1989) in 214 hospitalized children in pediatrics]. / Etude de validation de la version française de l'échelle de plaisir pour infants (EPE) de Kazdin (the pleasure scale for children, PSC, Kazdin, 1989) chez 214 enfants hospitalisés en pédiatrie.

UNLABELLED: The aim of this study was to determine the metrological parameters of a french version of the Pleasure Scale for Children (PSC): 214 (121 males and 93 females) with a mean age of 8.69 years (sd: 1.95) ranging from 6 years to 12 years were included in the study. The children were inpatients presenting various somatic disorders. STATISTICAL ANALYSIS: First a principal component analysis was done on the 39 items of the correlation matrix. Several guidelines were used to limit the number of factors (Kaiser criteria, Cattell scree test, Horn parallel analysis). Secondly the construct validity was studied using the alpha Cronbach coefficient and by calculing the Pearson correlation coefficient between each item and the total score. Thirdly the concurrent validity was determinated using two items of the Children Depression Rating Scale--Revised (CDRS-R) measuring pleasure (social withdrawal and enjoyment capacity). Fourthly the discriminant validity of the PSC was studied by comparing non depressive children (score lower than 30 to the CDRS-R) and depressive children (score higher than 30 to the CDRS-R). RESULTS: The principal component analysis showed a one factor solution with 33 items among the 39 having a higher than 0.3 saturation. The Cronbach alpha coefficient was 0.84. All the items correlated with the total score. The mean value was 0.37. The correlations between the total score of the scale and the CDRS-R enjoyment capacity and social withdrawal items were respectively -0.37 (p < 0.01) and -0.38 (p < 0.01). PSC score were significantly lower in depressive children (m = 86.96; sd = 8.33) than in non depressive children (m = 94.67; sd = 10) (t = 5.32; df = 212; p < 0.001).

[Evaluation of the subjective component of emotions in normal subjects: relation between anhedonia and the capacity to perceive unpleasant feelings in a population of 221 normal subjects]. / Evaluation de la composante subjective des émotions chez le sujet sain: rapport entre l'anhédonie et la capacité à éprouver du déplaisir dans une population de 221 sujets sains.

This work presents a study of 221 healthy subjects among whom we have assessed the capacity to feel pleasure or displeasure through two rating scales, the FCPCS-PP and the HDCS-PD. We have observed a significant correlation between the scores, which shows that the more pleasure the subject feels, the more displeasure he feels. These results seem to confirm the existence of an overall dimension of emotional experience.