Who is driving when unrestrained children and teenagers are hurt?

This paper examines driver characteristics in crashes where child and teenage motor vehicle crash victims were injured, in particular factors that determine whether or not the victim was restrained. Analyzing the data on children and teenagers who are injured revealed that the presence of a second adult in a vehicle increased the likelihood that these passengers were unrestrained. Other findings are more predictable: victim restraint use generally mirrored driver restraint use; a male driver, a young driver, a drinking driver, a speeding or reckless driver, an unlicenced or suspended driver, and a night-time trip each independently raised the odds that child and teenage passengers were not restrained when they were injured.     

Empirical scoring functions. II. The testing of an empirical scoring function for the prediction of ligand-receptor binding affinities and the use of Bayesian regression to improve the quality of the model

This paper tests the performance of a simple empirical scoring function on a set of candidate designs produced by a de novo design package. The scoring function calculates approximate ligand-receptor binding affinities given a putative binding geometry. To our knowledge this is the first substantial test of an empirical scoring function of this type on a set of molecular designs which were then subsequently synthesised and assayed. The performance illustrates that the methods used to construct the scoring function and the reliance on plausible, yet potentially false, binding modes can lead to significant over-prediction of binding affinity in bad cases. This is anticipated on theoretical grounds and provides caveats on the reliance which can be placed when using the scoring function as a screen in the choice of molecular designs. To improve the predictability of the scoring function and to understand experimental results, it is important to perform subsequent Quantitative Structure-Activity Relationship (QSAR) studies. In this paper, Bayesian regression is performed to improve the predictability of the scoring function in the light of the assay results. Bayesian regression provides a rigorous mathematical framework for the incorporation of prior information, in this case information from the original training set, into a regression on the assay results of the candidate molecular designs. The results indicate that Bayesian regression is a useful and practical technique when relevant prior knowledge is available and that the constraints embodied in the prior information can be used to improve the robustness and accuracy of regression models. We believe this to be the first application of Bayesian regression to QSAR analysis in chemistry.     

Seasonal fluctuations in plasma concentrations of luteinizing hormone and progesterone in Brahman (Bos indicus) and Hereford-Shorthorn (Bos taurus) cows grazing pastures at two stocking rates in a subtropical environment

The effects of day length and grazing intensity on seasonal fluctuations in plasma concentrations of luteinizing hormone (LH) and cyclic ovarian activity were determined in Brahman (Bos indicus) and Hereford-Shorthorn (Bos taurus) cows maintained at two stocking rates in a subtropical environment. Contemporary groups of ovariectomised cows were monitored for fluctuations in plasma concentrations of LH. Equal numbers (n = 5) of entire and ovariectomised Brahman and Hereford-Shorthorn cows were assigned to a pasture with a greater or lesser stocking rate. Over a 15-month period, live weight was recorded weekly, and a blood sample was taken at the same time for measurement of plasma LH in entire and ovariectomised cows, and plasma progesterone in entire cows. Plasma concentrations of progesterone were used as an index of cyclic luteal function (time of cessation or onset of oestrous cycles). Regression coefficients were calculated to determine the least-order regression coefficient (LORC; range 1st to 10 order) for which time of year explained at least 50% (r2 > 0.05) of changes in live weight, plasma LH, or plasma progesterone; regression coefficients of 4th and 5th order indicated seasonally-related changes in these variables. For all cows, live weight was greatest in late summer to early autumn and lowest in winter. Changes in live weight were more closely related to seasonal changes in pasture availability for cows on pastures at a greater stocking rate (LORC 4th-5th) than for cows on pastures at a lesser stocking rate (LORC 1st-3rd). Cyclic ovarian activity ceased in four Hereford-Shorthorn cows on pastures at a greater stocking rate in late autumn to early winter, and onset of oestrous cycles did not occur in all of these cows until late spring. Oestrous cycles were not detected in one of five cows in the other groups during different periods of the study; however, there were no apparent patterns to cessation of oestrous cycles in these groups. There were no seasonally-related changes in plasma LH in entire cows, at either stocking rate (LORC 10th; r2 = 0.16 to 0.41). In contrast, distinct seasonal fluctuations in plasma LH occurred in ovariectomised cows, with increases in spring and winter. Environmental cues induced greater fluctuations in plasma LH in ovariectomised cows at a greater stocking rate (LORC 3rd-5th; r2 = 0.71 to 0.72) compared with ovariectomised cows at a lesser stocking rate (LORC 3rd-5th; r2 = 0.53 to 0.58). The findings demonstrated that marked seasonal changes in reproductive activity of the hypothalamic pituitary axis can occur in cows with B. indicus and B. taurus genotypes in a subtropical environment; however, changes in plasma concentrations of LH are only apparent in ovariectomised cows. Concentrations of plasma LH in ovariectomised Brahman and Hereford-Shorthorn cows increased during winter, when pasture availability was limiting and cyclic luteal function ceased in four of five Hereford-Shorthorn cows.     

Peak expiratory flow and the resistance of the mini-wright peak flow meter

The purpose of this study was to examine whether the resistance of the peak flow meter influences its recordings. One hundred and twelve subjects, (healthy nonsmokers and smokers and subjects with lung diseases) performed three or more peak expiratory flow (PEF) manoeuvres through a Fleisch pneumotachograph with and without a mini-Wright peak flow meter added in random order as a resistance in series. The results were as follows. In comparison with a pneumotachograph alone, peak flow measured with an added mini-Wright meter had a smaller within-test variation, defined as the difference between the highest and second highest values of PEF in a series of blows. The mean (SE) variation was 14 (1.3) L.min-1 and 19 (1.5) L.min-1 with and without meter added, respectively. In comparison with the pneumotachograph alone, the addition of the mini-Wright meter caused PEF to be underread, especially at high flows. The difference (PEF with meter minus PEF without meter) = -0.064 (average PEF) -8 L.min-1; R2 = 0.13. The mean difference was -7.8 (1.1) %, and increased numerically for a given PEF, when maximal expiratory flow when 75% forced vital capacity remains to be exhaled (MEF75%FVC) decreased. The reproducibility criteria for repeated measurements of peak flow are more appropriately set at 30 L.min-1 than the commonly used 20 L.min-1, because a within-test variation of less than 30 L.min-1 was achieved in 76% of the subjects without PEF meter inserted and in 88% with meter inserted, with no difference between healthy untrained subjects and patients. The resistance of the peak expiratory flow meter causes less variation in recordings but reduces peak expiratory flow, especially at high values and when the peak is large as compared with the rest of the maximal expiratory flow-volume curve.     

Scapholunate ligament repair and capsulodesis for the treatment of static scapholunate dissociation

Twenty-four patients were treated with scapholunate ligament repair and dorsal capsulodesis for scapholunate dissociation. Seventeen patients were available for follow-up at an average of 30 months. The average interval between injury and surgery was 3 months. At final follow-up, no patients were pain-free. Average total wrist motion was 60% and grip strength 70% of the opposite normal side. The average preoperative scapholunate angle was 78 degrees and was corrected to a normal 47 degrees at surgery. The average final scapholunate angle was 72 degrees, which was not significantly different from the preoperative value. The scapholunate gap likewise was not significantly changed postoperatively. Only two patients had an excellent or good outcome using a clinical grading system, and six out of 17 scored good or excellent using a radiographic grading system. In conclusion, repair of the scapholunate ligament with dorsal capsulodesis failed to provide consistent pain relief and maintain carpal alignment in patients with static scapholunate instability.     

Hydrogen-induced microelectronic capacitor failure in pacemakers

Ceramic chip capacitors used in hybrid microelectronics for cardiac pacemakers are usually highly reliable. However, under certain conditions of capacitor construction, capacitor materials, mounting techniques, and environmental conditions, high failure rates may occur. A specific example is presented in which a ceramic capacitor used in an implanted pacemaker delaminated and failed approximately 30 days after being implanted. The failed capacitor caused a pulse rate rise, but due to circuit design techniques, the rate increase was limited to an acceptable value. The capacitor that failed was from an isolated lot of capacitors that was manufactured using pure palladium plates. The circuit containing this capacitor was hermetically sealed within a titanium case by welding. During the welding, a small amount of hydrogen was released from the titanium which, over a period of 2 to 4 weeks, was absorbed by the palladium plates in the capacitor. By absorbing the hydrogen, the palladium plates exhibit a volumetric expansion of sufficient magnitude to crack and delaminate the capacitor to the point of failure. Subsequently, the recurrence of this failure mode has been avoided by using capacitors containing special palladium alloys that cannot absorb hydrogen. This phenomenon is of interest to pacemaker designers since mercury batteries used in conventional pacemakers generate large amounts of hydrogen and potentially may be responsible for complications when used in conjunction with capacitors containing palladium.     

Gallium-67 scanning for carcinoma of the lung

Gallium-67 citrate scanning was prospectively evaluated in 55 patients who had lung lesions suspected to be primary carcinoma on chest x-ray films and in whom subsequent histologic diagnosis was obtained. Of 47 patients with histologically proved carcinoma of the lung, 44 (94 per cent) had a positive 67Ga scan. No patient with a positive scan had a benign lesion, so that the positive scan accuracy rate was 100 per cent. All 8 patients with a benign lesion and 3 patients with a malignant lesion had negative scans, for a negative scan accurary rate of 72 per cent for benign lesions. These results give statistical validity for the usefulness of the 67Ga scan in diagnosing carcinoma of the lung (p less than 0.001). Tumor cell type had little effect on the sensitivity of 67Ga scan. The 67Ga scan was equally useful in the evaluation of peripheral and central lesions. There was little difference amount T1, T2, and T3 classified lesions in their ability to take up 67Ga. The 67Ga scan was competitive with mediastinoscopy in assessing mediastinal lymph node metastases and provides a noninvasive method of assessing hilar lymph node metastases. There was a good correlation between the clinical staging of patients with lung cancer based on a chest x-ray film and 67Ga scanning and the staging after surgical treatment based on the histology of the resected specimens.     

Components of blood pressure and risk of atherothrombotic brain infarction: the Framingham study

From a study of the evolution of atherothrombotic brain infarction (ABI) in the Framingham cohort of 5,209 men and women over 18 years of follow-up, it has been ascertained that hypertensionis the most common and most powerful precursor. Atherothrombotic brain infarction developed in hypertensive patients seven times more often than in normotensive patients, and the risk was proportional to the blood pressure throughout its range.