Preliminary method for profiling volatile organic compounds in breath that correlate with pulmonary function and other clinical traits of subjects diagnosed with cystic fibrosis: a pilot study.

Cystic fibrosis (CF) is characterized by chronic respiratory infections which progressively decrease lung function over time. Affected individuals experience episodes of intensified respiratory symptoms called pulmonary exacerbations (PEx), which in turn accelerate pulmonary function decline and decrease survival rate. An overarching challenge is that there is no standard classification for PEx, which results in treatments that are heterogeneous. Improving PEx classification and management is a significant research priority for people with CF. Previous studies have shown volatile organic compounds (VOCs) in exhaled breath can be used as biomarkers because they are products of metabolic pathways dysregulated by different diseases. To provide insights on PEx classification and other CF clinical factors, exhaled breath samples were collected from 18 subjects with CF, with some experiencing PEx and others serving as a baseline. Exhaled breath was collected in Tedlar bags during tidal breathing and cryotransferred to headspace vials for VOC analysis by solid phase microextraction coupled to gas chromatography-mass spectrometry. Statistical significance testing between quantitative and categorical clinical variables displayed percent-predicted forced expiratory volume in one second (FEV1pp) was decreased in subjects experiencing PEx. VOCs correlating with other clinical variables (body mass index, age, use of highly effective modulator treatment (HEMT), and the need for inhaled tobramycin) were also explored. Two volatile aldehydes (octanal and nonanal) were upregulated in patients not taking the HEMT. VOCs correlating to potential confounding variables were removed and then analyzed by regression for significant correlations with FEV1pp measurements. Interestingly, the VOC with the highest correlation with FEV1pp (3,7-dimethyldecane) also gave the lowestp-value when comparing subjects at baseline and during PEx. Other VOCs that were differentially expressed due to PEx that were identified in this study include durene, 2,4,4-trimethyl-1,3-pentanediol 1-isobutyrate and 5-methyltridecane. Receiver operator characteristic curves were developed and showed 3,7-dimethyldecane had higher ability to classify PEx (area under the curve (AUC) = 0.91) relative to FEV1pp values at collection (AUC = 0.83). However, normalized ΔFEV1pp values had the highest capability to distinguish PEx (AUC = 0.93). These results show that VOCs in exhaled breath may be a rich source of biomarkers for various clinical traits of CF, including PEx, that should be explored in larger sample cohorts and validation studies.

Relevance of the popliteal angle to hamstring length in cerebral palsy crouch gait.

The popliteal angle is a widely used clinical means of assessing hamstring length in cerebral palsy patients. The relevance of the popliteal angle as a measure of hamstring length was assessed in this prospective study. Sixteen patients with cerebral palsy with crouch gait had their conventional and modified popliteal angles measured by nine observers on two separate occasions. With use of the conventional and modified forms of the test, 74 and 70%, respectively, of the observed variability was inter-and intraobserver related. The range of SDs for each observer using the conventional test was 7.1-13.6 degrees (average 10.9 degrees ), and with use of the modified form of the test, the range was 6.3-4.2 degrees (average 10.5 degrees ). The maximum hamstring length of each subject during gait was determined by three-dimensional modelling of their lower limbs. The modified popliteal angle measurements of the most repeatable observer demonstrated an inverse relationship between modified popliteal angle and maximum hamstring length (p < 0.01) and muscle excursion (p < 0.01). Only 10 of 32 limbs had short medial hamstrings.

Estimating economic thresholds for pest control: an alternative procedure.

An alternative methodology to determine profit maximizing economic thresholds is developed and illustrated. An optimization problem based on the main biological and economic relations involved in determining a profit maximizing economic threshold is first advanced. From it, a more manageable model of 2 nonsimultaneous reduced-from equations is derived, which represents a simpler but conceptually and statistically sound alternative. The model recognizes that yields and pest control costs are a function of the economic threshold used. Higher (less strict) economic thresholds can result in lower yields and, therefore, a lower gross income from the sale of the product, but could also be less costly to maintain. The highest possible profits will be obtained by using the economic threshold that results in a maximum difference between gross income and pest control cost functions.

W. Edwards Deming, quality analysis, and total behavior management.

During the past 10 years, the inclusion of the word "quality" in descriptions of production methods, management approaches, educational systems, service system changes, and so forth, has grown exponentially. It appears that no new approach to any problem is likely to be given much consideration today without overt acknowledgment that some improvement in quality must be the outcome. The origins of the importance of quality are primarily rooted in the awakening recognition of the influence of W. Edwards Deming in the post-World War II restoration of Japanese industry. We provide a brief overview of Deming's approach to modernizing management methods and discuss recent criticisms from the field of organizational behavior management that his approach lacks emphasis on the role of reinforcement. We offer a different analysis of Deming's approach and relate its evolution to the contingencies of reinforcement for the behavior of consulting. We also provide an example of problem solving with Deming's approach in a social service setting familiar to many behavior analysts.

A program evaluation of classroom data collection with bar codes.

A technology incorporating bar code symbols and hand-held optical scanners was evaluated for its utility for routine data collection in a special education classroom. A different bar code symbol was created for each Individualized Educational Plan objective, each type of response occurrence, and each student in the first author's classroom. These symbols were organized by activity and printed as data sheets. The teacher and paraprofessionals scanned relevant codes with scanners when the students emitted targeted behaviors. The codes, dates, and approximate times of the scans were retained in the scanner's electronic memory until they could be transferred by communication software to a computer file. The data from the computer file were organized weekly into a printed report of student performance using a program written with commercially available database software. Advantages, disadvantages, and costs of using the system are discussed.

Diets for Rearing the Ambrosia Beetle Xyleborus ferrugineus (Fabricius) in vitro.

Female ambrosia beetles placed on media containing sucrose, yeast extract, casein, starch, wheat germ, cottonseed oil, salt mixture, agar, water and cacao sawdust or powdered cellulose excavated galleries, oviposited, and produced progeny that developed to maturity. Several generations have been raised in the laboratory on media inoculated with ambrosia fungi by the beetles.