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The purpose of this study was to evaluate critical power (W(CP)) as an indicator of aerobic fitness in trained cyclists, and to determine its relationship to cycling time trial (TT) performance. Thirteen competitive USCF category 2 or 3 cyclists provided season's best 40 km TT times (mean [SD]) time = 59.6 min (3.1), and performed two 17 km TT under controlled conditions (26.6 min [1.1]). Ventilatory threshold (VT) and VO2max were determined from a maximal incremental test. W(CP) was calculated using the results of four all-out constant power tests. Mean W(CP) was 299 (61) W or 4.1 W x kg(-1), VT was 3616 (750) ml x min(-1) or 49.8 ml x kg(-1) x min(-1) (7.5), and VO2max was 4596 ml x min(-1) or 63.5 ml x kg(-1) x min(-1) (8.0). W(CP) was strongly related to VT and VO2max, demonstrating that it can serve as a measure of aerobic fitness in this population. Expressions of W(CP) were slightly to considerably more highly related to 17 km and 40 km TT performances (r = -0.77 to -0.91) than were expressions of VT and VO2max (r = -0.71 to -0.87). It is concluded that W(CP) provides an aerobic fitness measure for competitive cyclists which can be obtained without invasive testing. In addition, W(CP) is strongly related to the TT performance of competitive cyclists.

The use of process and two-dimensional clarifier modelling to investigate the implications of upgrading Melbourne Water's Eastern Treatment Plant to a nitrification/denitrification process is discussed. Results indicate that the existing clarification capacity is sufficient for the increased solids loading arising from operation at a nitrifying sludge age but that the existing diffuser system may need to be replaced in order to achieve the required oxygen transfer rate. The impact of step feeding into unaerated zones to reduce the aeration tank suspended solids concentration and to achieve denitrification is discussed and the installation of baffles to improve the performance of peripheral feed clarifiers is suggested.

This paper considers the rationale for the exploration of Saturn's atmosphere by the Cassini mission, taking account of the key scientific questions posed by the earlier investigation by Voyager, and the capabilities of the instrumentation making up the Cassini payload. While by no means all objectives can be addressed by this particular configuration, in particular without a Saturn entry probe, if everything goes according to plan important progress should be possible on a number of key objectives. (C) 1998 Elsevier Science Ltd. All rights reserved.

The objective of this study was to assess daily self-selected mineral intake of free-living African-American adults using the duplicate portion collection technique coupled with direct chemical analysis. A duplicate sample of every food and beverage consumed was collected by each subject. The collection period was for 3 days (Sunday, Tuesday, and Thursday) of 1 week in 1986. The chemical analysis included calcium, phosphorus, magnesium, sodium, potassium, manganese, iron, copper, zinc, and phytate. Forty adult African-Americans (20 females and 20 males) living in the Washington, DC area volunteered to participate. They were apparently healthy, ranging in age from 21 to 65 years, with a median age of 38.5 years. The analytical data from the daily food and beverage intake were compared with the Recommended Dietary Allowances (RDA)/ Estimated Safe and Adequate Daily Dietary Intakes (ESADDI). The results were also compared with data from the National Health and Nutrition Examination Survey (NHANES) III and USDA's Continuing Survey of Food Intakes by Individuals(USDA-CSFII 1989–91). Compared with the RDA/ESADDI, for women, the median intakes of less than two-thirds the recommendations were : calcium (54%), magnesium (65%), iron (61%), copper(60%), zinc (61%), and potassium (50%) as determined by chemical analysis. For the men, applying the same criteria, the minerals and percentages are: calcium (64%), magnesium (56%), copper (60%), zinc (61%), and potassium (58%). The phytate:zinc and phytate × Ca:Zn molar ratios suggested no general inhibition of zinc bioavailability despite some higher than suggested limiting molar ratios found in a few individual daily diets. Although limited in scope, these results suggest that African-American adults are selecting diets that are frequently low in specific minerals. Some of these essential nutrients have been implicated in chronic health problems prevalent in this ethnic group; e.g., hypertension and cardiovascular diseases. Therefore, nutritionists and other health professionals should emphasize the need for a wider selection of foods to prevent specific mineral deficits. These foods might include acceptable dairy products, meats/seafood, and mineral-fortified cereals/breads and juices.

The spectra of 43 aliphatic hydrocarbons have been measured between 3900 and 6000 cm-1. It is shown that they can be represented as the sum of a limited set of group spectra. The required number of groups is established using principal factor analysis. A theorem is derived by which these group spectra can be determined directly from the eigenspectra (scores) and eigenvectors of the covariance matrix of the spectral data (loadings). Group spectra, integrated over 4 cm-1 intervals, are presented for n-alkylmethylene and methyl, isopropyl, tert-butyl, 2,3-dimethylpropyl, and midchain methyl, ethyl and m,m-dimethyl. Using these the average error was 2.2% for the 35 compounds in the set for which the chain branchings were separated by more than one methylene unit. This corresponds to an average predictive error of 0.0004 molar absorbance units (mol dm-3 cm). For CH2 chains with isopropyl units (six spectra) the average error is 2.5%. These figures were comparable both with the deviations in the total integrate...

The scientific community has recently focused its concerns on possible developmental delays in infants exposed to methylmercury via maternal fish consumption. In this study, the authors reported levels of methylmercury in hair specimens that corresponded to 2820 monthly seafood consumption diaries recorded by U.S. women of childbearing age. In this study, the geometric mean hair methylmercury level for diarists who reported some seafood consumption was 0.36 ppm (one geometric standard deviation [GSD] range = 0.14-0.90 ppm); the corresponding value for diarists who reported no seafood consumption was 0.24 ppm (one GSD range = 0.09-0.62 ppm). Therefore, the mean hair methylmercury level associated with seafood consumption was 0.12 ppm (one GSD range = 0.05-0.32 ppm). The results of this study provide evidence that levels of methylmercury in the U.S. population are quite low. There is a significant contribution to hair methylmercury from sources other than seafood. It is not likely that maternal hair methylmercury levels in the range found in our study would be associated with adverse health effects in children.

Congestive heart failure occurring in unoperated patients with otherwise uncomplicated tetralogy of Fallot (TF) is rare. We report the case of a boy who was first diagnosed as having TF when he presented at age 3 years with hypoxia and heart failure. Heart failure improved following an aortopulmonary shunt. We attributed his heart failure to cardiomyopathy associated with severe hypoxia. We believe that this report is the first one that attributes heart failure to hypoxia in an unoperated patient with tetralogy of Fallot.

Facial cooling (FC) elicits a marked bradycardia at rest that appears to be reduced during exercise. This study was done to delineate the effects of exercise mediated central command from those of muscle afferent feedback and sympathetic stimulation on the attenuation of the bradycardic effect of FC during the onset of exercise. Ten healthy subjects (26 +/- 2 yr) were exposed to FC under five different conditions: 1) seated rest on the cycle ergometer, 2) onset of mild exercise (resting HR + 20 beats.min-1), 3) onset of moderate exercise (resting HR + 50 beats.min-1), 4) seated rest on the ergometer during electrical stimulation, and 5) seated rest on the ergometer during a cold immersion test (CT) (one hand immersed in an ice slurry at 0 degree C). The two exercise intensities were presumed to provide different degrees of central command. Electrical stimulation of the quadriceps was assumed to provide isolated muscle afferent feedback, while the CT served as a sympathetic stimulus. Beat-by-beat data were recorded for HR and mean arterial blood pressure for the duration of each test (50 s), and a rating of perceived pain was taken after each FC. FC elicited significant increases in mean arterial pressure during mild and moderate exercise compared with resting control (P0.05) and during moderate exercise compared to exercise without FC (P0.05). Mean decreases in HR during FC were similar for resting control (-12 +/- 3 beats.min-1), electrical stimulation (-10 +/- 3 beats.min-1), and CT (-9 +/- 3 beats.min-1). The HR response to FC during mild exercise (-7 +/- 2 beats.min-1) was significantly different (P0.05) from the rest condition; however, there was no significant bradycardia (-2 +/- 2 beats.min-1; P0.05) during onset of moderate exercise. These findings suggest that the magnitude of cold face-induced bradycardia may be attenuated at exercise onset by neural signals related to the higher levels of central motor command associated with heavier exercise.

Optical QND measurements may be made using devices which act as nonlinear beam splitters, transmitting noise in a phase-sensitive way. One class of such devices are resonant optical cavities containing a nonlinear medium. By appropriate choice of nonlinearity and operating parameters, various QND observables may be measured. We consider, in particular, the extent to which the QND performance of these devices is degraded by intracavity losses.

Although two thirds or more of patients with microprolactinoma achieve normal serum prolactin levels over the long term after withdrawal of dopamine agonist therapy, there is no agreement on the appropriate duration of treatment, and treatment is not always interrupted. In this retrospective analysis of 89 patients, 84 women and 5 men with a mean age of 33 years, remissions were analyzed in 67 patients treated with 0.5 to 3 mg cabergoline weekly and 22 others given 2.5 to 10 mg bromocriptine daily. The mean duration of therapy was 3.1 years, and patients were followed for at least 1 year after treatment ended. None of the patients received medication other than a dopamine agonist. Seven women discontinued treatment when they became pregnant. All patients were symptomatic and hyperprolactinemic when first seen. Among 57 patients (64%) who had a recurrence after treatment stopped were 46 (81%) who had recurrent symptomatic hyperprolactinemia within 12 months after stopping treatment. The average interval was 9.6 months. Thirty-two patients, 36% of the total, achieved remission after at least 1 year of follow up; the mean duration of remission was 3.6 years. Nearly 85% of these patients remained in remission for longer than 2 years. Four of them were asymptomatic despite being hyperprolactinemic. The 2 dopamine agonists were equally effective. The overall median duration before relapse after discontinuance of treatment was 12 months. Logistic regression analysis failed to demonstrate an association between the risk of recurrence and age at presentation, imaging of an adenoma, or the duration of treatment. When dopamine agonist therapy is abruptly withdrawn after 2 years or longer in patients with microprolactinoma, 30% to 40% achieve long-term remission without side effects. Because symptomatic hyperprolactinemia may develop more than 1 year after treatment stops, long-term follow up is essential.

The concentrations of the elements copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in hair of caged (in Maryland) and free-ranging (in Puerto Rico) rhesus monkey populations were determined. Significant chronological age-related decreases were evident for the trace elements Mn and Zn in both populations (Por = 0.01) and for Cu and Fe in free-ranging monkeys (Por = 0.005). The only overall gender difference was higher hair Mn concentration in free-ranging males than in females (P0.03). There were no significant differences in hair Cu, Fe, or Mn related to pregnancy status. Hair Zn was lower in samples from pregnant than from nonpregnant monkeys from the caged monkeys (Por = 0.05), but did not differ in the free-ranging monkeys. Comparison of the two populations revealed that hair Zn levels were significantly higher in caged vs free-ranging animals (P0.001). We attribute this higher hair Zn in the caged monkeys to contact and ingestion of Zn from their galvanized enclosures. Hair iron levels were significantly higher (P0.001) in free-ranging monkeys, possibly as a result of Fe-rich soil ingestion from their environment. These data support continued investigation of the use of hair as an indicator of the exposure of large groups or populations to potentially high levels of specific minerals, and the use of nonhuman primates as models for the study of trace element deficiency and/or toxicity in humans.

This paper responds to research into the aerodynamics of flapping wings and to the problem of the lack of an adequate method which accommodates large-scale trailing vortices. A comparative review is provided of prevailing aerodynamic methods, highlighting their respective limitations as well as strengths. The main advantages of an unsteady aerodynamic panel method are then introduced and illustrated by modelling the flapping wings of a tethered sphingid moth and comparing the results with those generated using a quasi-steady method. The improved correlations of the aerodynamic forces and the resultant graphics clearly demonstrate the advantages of the unsteady panel method (namely, its ability to detail the trailing wake and to include dynamic effects in a distributed manner).

Avian influenza (AI) is a highly contagious viral infection, which can affect all species of birds. Highly pathogenic avian influenza (HPAI) viruses can spread rapidly, causing serious disease with high mortality in many bird species. Wild birds are recognised as the reservoir for low-pathogenicity AI virus and have been shown to play a role in the long-distance transmission of HPAI viruses. In April 2006, H5N1 HPAI (Eurasian lineage) was detected in a dead Whooper swan ( Cygnus cygnus ) in Scotland, marking the first detection of H5N1 HPAI virus in Great Britain since 1959. At the time of the outbreak, risk tools were developed collaboratively between the Veterinary Laboratories Agency, the British Trust for Ornithology, the Wildfowl and Wetlands Trust and Defra to support assessments of the likelihood of the introduction and spread of H5N1 HPAI via wild bird migratory movements to and within Great Britain (Crick and others 2006). A risk-based surveillance model was developed to identify areas in which commercial poultry were at the greatest risk of incursion of H5N1 HPAI from wild birds (Snow and others 2007). The resulting risk map was used by government to prioritise AI surveillance activities including the testing of wild birds found dead for H5N1 HPAI as mandated within the EU AI surveillance framework (Hesterberg and others 2009). This geospatial risk modelling tool has recently been updated to provide revised estimates of these geographical areas and was used as part of the evidence base to assess the risk of incursion from wild …

In 1980, J. C. Smith asked for examples which would demonstrate the relationships between the properties B ( D , λ ) B(D,\lambda ) -refinability, B ( D , ω 0 ) B(D,{\omega _0}) -refinability, and weak θ ¯ \bar \theta -refinability. This paper gives such examples in the class of T 4 {T_4} spaces.

To identify the most suitable method to continuously monitor antibiotic prescriptions in a United Kingdom hospital, a study was performed in three phases over four years between 1985 to 1989 in a Liverpool teaching hospital. The aim of the study was to perfect a method to collect and analyse hospital-wide antibiotic prescribing data. The emphasis was laid on identifying problems and practicalities and also to minimize manpower and resource requirements. The data were used to illustrate the effect of the hospital's antibiotic policy on prescribing trends. The policy recommendation that co-trimoxazole be substituted by trimelhoprim was only partially adhered to because Augmentin® was the other replacement antibiotic in a significant number of cases. Therefore, it is important to monitor the effects of target drug programmes on all antibiotics since certain sequelae may be unexpected. A total of 1,804, 2,526 and 3,226 antibiotic prescriptions were collected and analysed during phases I, II and III respectively. 72–73% of the prescriptions were for the treatment of infection which equated to 81–89% of the total antibiotic cost. Therefore, cost control campaigns need to concentrate on infection treatment as opposed to prophylaxis. Specifically, respiratory tract, septicaemia and pyrexias of unknown origin account for the bulk of antibiotic expenditure. The method for phases I and II was multidisciplinary and very time-consuming. Phase III was very fast in operation, with data collection and analysis being performed on a single computer dedicated for the task. The minimum staff required to monitor all antibiotic prescriptions is one full-time pharmacist and clerk. Continuous intensive antibiotic monitoring in United Kingdom hospitals will not be feasible until antibiotic prescription forms are introduced on all wards.

With the introduction of interventional procedures such as percutaneous mitral valvuloplasty and radiofrequency ablation of left-sided bypass tracts, there has been renewed interest in the technique of transseptal left heart catheterization. We review our experience with 1,279 transseptal catheterizations performed over the last 10 years. The most common indications for transseptal catheterization included direct measurement of left atrial pressure or access to the left ventricle in patients with prosthetic aortic or mitral valves, and in patients undergoing percutaneous mitral valvuloplasty. A total of 17 major complications occurred (1.3%), including cardiac tamponade (15 patients, 1.2%), systemic emboli (1 patient, 0.08%), and death secondary to aortic perforation (0.08%). We conclude that when performed by experienced operators, transseptal left heart catheterization is associated with low morbidity and mortality.

To examine the influence of inositol phosphates on the uptake and absorption of Fe and Zn, Caco-2 cells were grown on either plastic (uptake studies) or porous membranes in bicameral chambers (transport/absorption studies). Caco-2, a human colon adenocarcinoma cell line, was selected as the test cell because it spontaneously differentiates into polarized enterocyte-like cells at confluency. Uptake of Fe (added as Fe-nitrilotriacetate complex) from a calcium-free solution by fully differentiated cells was 37 pmol/cm2. Addition of 10-fold molar excess of individual inositol phosphates (IP3, IP4, IP5 or IP6) decreased Fe solubility by 13 to 25% and reduced Fe uptake by 50 to 65%. The rate of transport of Fe from the apical solution into the basolateral chamber [1.4 +/- 0.1 pmol/(h.cm2)] decreased (34-96%) in proportion to the degree of phosphorylation of the inositol derivative in the apical compartment. Uptake and transepithelial transport of Zn were 246 +/- 5 pmol/cm2 and 23 +/- 1 pmol/(h.cm2), respectively. The solubility, uptake and rate of transport of Zn also decreased in proportion to the degree of phosphorylation of inositol. These results demonstrate the inhibitory influence of IP3-IP6 on the uptake and transport of Fe and Zn and support the usefulness of the Caco-2 human cell line as an appropriate model for evaluating the effects of specific dietary factors on trace metal bioavailability.

In an initial study of 20 fresh ovarian tumour samples, we compared the immunohistochemical positivity of staining of the p53 protein with the presence of missense mutations of the p53 gene. This revealed a prevalence of 50% with a perfect correlation between mutation and immunohistochemical staining. Detection of the p53 protein by immunohistochemistry was, therefore, used as a reliable indicator for the presence of P53 mutation, and was applied to a study of an archival series of 93 ovarian tumours. Positive immunostaining of the p53 protein was observed in 47% of this series. Cox regression was used to assess whether various clinical variables and P53 mutation were related to survival. As a result, it was found that positive staining of the p53 protein was independent of age, tumour differentiation, tumour type, though possibly not stage. There was some evidence that p53 positivity was associated with reduced survival after adjusting for other variables, but the result was not statistically significant.

A newly available carotenoid food-composition database providing specific carotenoid values for > 2300 foods was linked to dietary data on 57 male nonsmokers to examine the association between dietary carotenoid intake and plasma carotenoid concentrations over 3 wk when free-living. Carotenoid intake was estimated from a food-frequency questionnaire (FFQ) and 7 d of food diaries with concurrent analysis of plasma carotenoid concentrations. After adjustment for energy intake, percentage of energy from alcohol, and plasma lipid concentrations, significant diet-plasma correlations for the FFQ and the food diaries (FD) included alpha-carotene (r = 0.29 and 0.43), beta-carotene (r = 0.36 FFQ only), beta-cryptoxanthin (r = 0.46 and 0.44), lutein (r = 0.44 FD only), and lycopene (r = 0.53 FD only). Dietary carotenoid intakes were associated with plasma carotenoid concentrations for all the carotenoids except for beta-carotene when food diaries were used whereas the diet-plasma correlation for the provitamin A carotenoids were consistently significant when the FFQ was used.

Methods of extracting the spectra of functional groups from a spectral collection are reviewed. A new method is described based on principal component analysis. Application of multiple-regression analysis and PCA to the mid infra-red spectra of thio ethers and to alkanes are used to generate quantitative spectra of -S-(CH2)nCH3 (n=0,1,2) and of (CH3)2CH.CH2− in the spectral region 3075-2700cm−1 and 1500-1350 cm−1. Near i.r. spectra of n-alkanes are analysed to generate the spectra of CH3 and CH2 from 10,000 to 3600 cm−1. The group spectra so generated are discussed.

Three studies were performed to evaluate the effects of jet lag on factors associated with sport performance. In Study 1, members of the USA Women's Soccer Team traveled to Taiwan; in Study 2, North American students and faculty traveled to Western Europe; and in Study 3, European students traveled to North America. After travel, there was disruption of mood state and a reduction in dynamic strength; peak 5-s power and 30-s work capacity were reduced for 2 days (5-s power: 9.8 vs. 9.0 vs. 9.0 W∙kg−1; 30-s work capacity: 213 vs. 199 vs. 201 J∙kg−1). In these studies, mood state, anaerobic power and capacity, and dynamic strength were affected by rapid transmeridianal travel, and even highly trained athletes suffered from jet lag. However, effects of travel on the variables tested were essentially eliminated after 3 or 4 days. Key words: circadian rhythm, anaerobic power, anaerobic capacity, mood, travel

Contrary to a previous report that Birch reduction of C60 affords C60H36 as the principal product, laser desorption-laser photoionisation time-of-flight (L2TOF), laser desorption Fourier transform ion cyclotron resonance (FTICR), and liquid secondary ion mass spectrometry (LSIMS) show collectively that a mixture of polyhydrofullerenes, containing C60H18 through to C60H36 with a skewed distribution centred on C60H32 is formed, the discrepancy in results arising from the thermal lability of this mixture of polyhydrofullerenes when subjected to the elevated temperatures (>250 °C) required for mass spectroscopic studies using direct-insertion heated probes.

Contrary to a previous report that Birch reduction of C60 affords C60H36 as the principal product, laser desorption-laser photoionisation time-of-flight (L2TOF), laser desorption Fourier transform ion cyclotron resonance (FTICR), and liquid secondary ion mass spectrometry (LSIMS) show collectively that a mixture of polyhydrofullerenes, containing C60H18 through to C60H36 with a skewed distribution centred on C60H32 is formed, the discrepancy in results arising from the thermal lability of this mixture of polyhydrofullerenes when subjected to the elevated temperatures (>250 °C) required for mass spectroscopic studies using direct-insertion heated probes.

Helicobacter pullorum is a bacterial pathogen in humans. By using microaerobic culture techniques, H. pullorum was isolated from the feces of barrier-maintained mice and identified, on the basis of biochemical, restriction fragment length polymorphism, and 16S rRNA gene sequence analyses. This finding presents an opportunity to study H. pullorum pathogenesis in mice.

Previous surveys suggested that young children in Northeast Thailand may benefit from vitamin A and/or zinc supplementation. One hundred thirty-three children aged 6-13 y with marginal plasma retinol (less than 1.05 mumol/L) and Zn (less than 12.2 mumol/L) concentrations participated in a double-blind study. They were randomly assigned and supplemented with either zinc (25 mg/d), vitamin A (1500 RE/d), zinc plus vitamin A, or placebo for 6 mo. Biochemical indices of vitamin A (plasma vitamin A, retinol-binding protein) and zinc status (plasma zinc, alkaline phosphatase) increased significantly. The children had adequate liver stores of vitamin A (relative dose response less than 20%). Zinc supplementation resulted in an improvement in vision restoration time (VRT) in dim light (dark adaptometry). Vitamin A and zinc synergistically normalized conjunctival epithelium as measured by conjunctival impression cytology (CIC). Both functional indices, VRT and CIC, showed significant correlations with plasma zinc and vitamin A, respectively. The data suggest that functional improvements in populations with suboptimal vitamin A and zinc nutriture can be accomplished by supplementation with less than two times the recommended dietary allowance of these nutrients.

ABSTRACI’ We determined serial changes in four major plasma carotenoid fractions (a-carotene, /3-carotene, lutein/ zeaxanthin, and lycopene) in 30 men consuming defined daily doses of carotenoids from foods (broccoli, carrots, or tomato juice) or from purified /3-carotene in capsules (12 or 30 mg) for 6 wk while fed a controlled diet. Compared with baseline, /3carotene increased in the 30- and 12-mg-capsule and carrot groups whereas a-carotene increased in the carrot group and lutein increased in the broccoli group. Lower lutein concentrations in recipients of/3-carotene capsules suggested an interaction between these two carotenoids. Lycopene declined in all groups except the tomato-juice group. Total carotenoid concentration changes only reflected the large increases in /3-carotene concentrations and not the smaller changes observed in other individual carotenoids. Overall, purified /3-carotene produced a greater plasma response than did similar quantities ofcarotenoids from foods sources. However, some foods increased plasma concentrations of certain carotenoids. Am J C/in Nutr l992;55

One of the reasons that we know so little about the control of vertebrate gastrulation is that there are very few systems available in which the process can be studied in vitro. In this paper, we suggest that one suitable system might be provided by the use of mesoderm-inducing factors. In amphibian embryos such as Xenopus laevis, gastrulation is driven by cells of the mesoderm, and the mesoderm itself arises through an inductive interaction in which cells of the vegetal hemisphere of the embryo emit a signal which acts on overlying equatorial cells. Several factors have recently been discovered that modify the pattern of mesodermal differentiation or induce mesoderm from presumptive ectoderm. Some of these mesoderm-inducing factors will also elicit gastrulation movements, which provides a powerful model system for the study of gastrulation, because a population of cells that would not normally undertake the process can be induced to do so. In this paper, we use mesoderm-inducing factors to attempt to answer four questions. How do cells know when to gastrulate? How do cells know what kind of gastrulation movement to undertake? What is the cellular basis of gastrulation? What is the molecular basis of gastrulation?

1. Pulmonary arterial hypertension was demonstrated in a series of rats that had been kept for 24–31 days in an environment of compressed air, having a barometric pressure of 3040 mm. Hg. The partial pressure of oxygen was 635 mm. Hg, which is equivalent to an 83.6 per cent oxygen mixture at normal barometric pressure. 2. Sclerosing changes in the pulmonary arterioles have been observed which precede the development of demonstrable hypertension in the pulmonary circulation. These vessels showed histological changes that were indicative of injury after 3 days of exposure. There was a thickening of the walls which stained more intensely with eosin, as well as marked perivascular edema and often a narrowing of the lumina. Progressive thickening, narrowing, and hyalinization of the pulmonary arterioles occurred later, after the disappearance of perivascular edema. These changes appeared very similar to the renal arterial lesions seen at autopsy in patients dying from malignant hypertension. 3. Pathological examination did not reveal significant or constant changes from normal in any organs except the lungs and heart. The blood vessels of the systemic circulation showed no pathological change. 4. The walls of the large pulmonary arteries increased in thickness rapidly after the 3rd day of exposure. This change was due to the progressive formation and condensation of fibrous tissue outside of the media and to a lesser extent to thickening of the alternate layers of elastic tissue and smooth muscle in the arterial wall. 5. Marked dilatation of the right ventricle and conus arteriosus as well as small areas of scar tissue formation in the right ventricle were present on prolonged exposure. A few hearts showed larger areas of fibrosis that were visible on macroscopic examination. 6. The systemic arterial blood pressure of a small series of rats exposed to compressed air for 38 days and examined 7 to 10 days after decompression was in each instance less than one-half the average normal pressure. 7. The findings in this study are consistent with the clinical and pathological signs of pulmonary hypertension in man. 8. The anatomical alterations observed in the alveolar units of the lungs were essentially the same as those previously described (1). 9. A method has been devised whereby pulmonary arterial hypertension, accompanied by important sclerotic changes in the arteries of the pulmonary circulation can be induced for investigation.

We studied respiratory neural activity generated during expiration. Motoneuronal activity was recorded simultaneously from abdominal (AbN), phrenic (PN), hypoglossal (HN) and central vagus nerves from neonatal and juvenile rats in situ. During eupnoeic activity, low-amplitude post-inspiratory (post-I) discharge was only present in AbN motor outflow. Expression of AbN late-expiratory (late-E) activity, preceding PN bursts, occurred during hypercapnia. Biphasic expiratory (biphasic-E) activity with pre-inspiratory (pre-I) and post-I discharges occurred only during eucapnic anoxia or hypercapnic anoxia. Late-E activity generated during hypercapnia (7-10% CO(2)) was abolished with pontine transections or chemical suppression of retrotrapezoid nucleus/ventrolateral parafacial (RTN/vlPF). AbN late-E activity during hypercapnia is coupled with augmented pre-I discharge in HN, truncated PN burst, and was quiescent during inspiration. Our data suggest that the pons provides a necessary excitatory drive to an additional neural oscillatory mechanism that is only activated under conditions of high respiratory drive to generate late-E activity destined for AbN motoneurones. This mechanism may arise from neurons located in the RTN/vlPF or the latter may relay late-E activity generated elsewhere. We hypothesize that this oscillatory mechanism is not a necessary component of the respiratory central pattern generator but constitutes a defensive mechanism activated under critical metabolic conditions to provide forced expiration and reduced upper airway resistance simultaneously. Possible interactions of this oscillator with components of the brainstem respiratory network are discussed.

The role of microstructure on flux pinning in c-axis-oriented epitaxial ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{\mathit{x}}$ films grown on ${\mathrm{LaAlO}}_{3}$ and ${\mathrm{SrTiO}}_{3}$ has been studied. For a magnetic field parallel to the Cu-O planes, the resistivity and critical current density ${\mathit{J}}_{\mathit{c}}$ have been measured as a function of the angle \ensuremath{\theta} between the applied field and the direction of the transport current. In addition to a Lorentz-force-independent resistivity, the Lorentz-force-dependent component showed several broad deviations from ${\mathrm{sin}}^{2}$\ensuremath{\theta} when a field was aligned parallel to certain microstructural features which vary with the film thickness and substrate material. These features were identified by transmission-electron-microscopy analysis. For films of 5000 \AA{} thickness on ${\mathrm{LaAlO}}_{3}$, resistivity dips were observed for a field applied parallel to the substrate twin boundaries or along misoriented a-axis grains. In thinner films of 900 \AA{} thickness also on ${\mathrm{LaA}1\mathrm{O}}_{3}$ in which a-axis grains were negligible, we observed dips corresponding to the orientation of substrate twin boundaries only. For thin films on ${\mathrm{SrTiO}}_{3}$ in which substrate twins are absent, resistivity dips corresponding to the direction of twin boundaries in the film and, perhaps, interfacial dislocations were observed. Overall, such dips decreased with increasing transport current density and became negligible in ${\mathit{J}}_{\mathit{c}}$ measurements.

Nitzschia pungens f. multiseries (clone NPARL) was grown in nonaxenic batch culture under a range of growth conditions. Domoic acid (DA) was not detected during exponential growth, but production promptly started at a rate of approximately 1 pg DA∙cell−1∙d−1 at the onset of the stationary phase, in this case induced by silicate limitation. Cellular DA reached a maximum of 7 pg∙cell−1; thereafter, DA production continued at the same rate, with cellular levels remaining relatively constant due to concurrent release of DA into the culture medium. DA production ceased in the absence of nitrogen during the stationary phase, but resumed when nitrate was added back to the medium. Low irradiance slowed the division rate and consequently delayed the attainment of the stationary phase, but DA production rates were comparable with the control once stationary phase was reached. Cells during the dark period of a light–dark cycle, or placed into darkness, or in the presence of the photosynthetic inhibitor DCMU promptly ceased DA production. We conclude that at least three conditions are required for DA production by clone NPARL: cessation of cell division, availability of nitrogen during the stationary phase, and the presence of light. Growth in medium f/2 fulfils these requirements.

This paper reports that the possible alternatives to the slider-crank for internal combustion engine use, the Scotch yoke in its various forms and inversions has received considerable attention. Among these, the Stiller-Smith mechanism has shown promise as being a viable option. Kinetostatic models were formulated to determine loading within similar eight-cylinder, four-stroke, compression-ignition engines with emphasis placed on comparing the number and similarity of mechanism components, implications of component and linkage motions, the loading experienced by similar bearing surfaces, and the friction losses of specific components.

The collagen VI muscular dystrophies, Bethlem myopathy and Ullrich congenital muscular dystrophy, form a continuum of clinical phenotypes. Glycine mutations in the triple helix have been identified in both Bethlem and Ullrich congenital muscular dystrophy, but it is not known why they cause these different phenotypes.We studied eight new patients who presented with a spectrum of clinical severity, screened the three collagen VI messenger RNA for mutations, and examined collagen VI biosynthesis and the assembly pathway.All eight patients had heterozygous glycine mutations toward the N-terminal end of the triple helix. The mutations produced two assembly phenotypes. In the first patient group, collagen VI dimers accumulated in the cell but not the medium, microfibril formation in the medium was moderately reduced, and the amount of collagen VI in the extracellular matrix was not significantly altered. The second group had more severe assembly defects: some secreted collagen VI tetramers were not disulfide bonded, microfibril formation in the medium was severely compromised, and collagen VI in the extracellular matrix was reduced.These data indicate that collagen VI glycine mutations impair the assembly pathway in different ways and disease severity correlates with the assembly abnormality. In mildly affected patients, normal amounts of collagen VI were deposited in the fibroblast matrix, whereas in patients with moderate-to-severe disability, assembly defects led to a reduced collagen VI fibroblast matrix. This study thus provides an explanation for how different glycine mutations produce a spectrum of clinical severity.

The objective of this laboratory study was to assess the Sensodyne Mikro Aktiv extra soft toothbrush, compared with the Oral-B Indicator soft toothbrush, for interproximal access efficacy (IAE).Six toothbrushes of each product were tested four times, for a total of twenty-four tests on each toothbrush design. In the IAE assay, the tooth brushing technique involved independent evaluations of each toothbrush in a vertical or horizontal brushing motion, tooth shapes simulating anterior and posterior teeth, and a brushing weight of 250 g. The brushing apparatus was set to brush for 15 seconds at two strokes per second with a 50 mm stroke. All readings were measured with 3x magnification by a single investigator.The mean IAE value on anterior tooth shapes, with vertical and horizontal brushing, was significantly (p0.001) higher for the Sensodyne Mikro Aktiv toothbrush than for the Oral-B Indicator toothbrush. When the IAE values were combined to give an overall brushing average, the Sensodyne Mikro Aktiv toothbrush was significantly (p0.001) higher compared to the Oral-B Indicator toothbrush.The Sensodyne Mikro Aktiv toothbrush has demonstrated superiority to the Oral-B Indicator toothbrush for access into interproximal areas using this laboratory methodology.

Bi-level optimization algorithms have been developed for use in a variety of problems, including network design and defense systems and optimization under uncertainty, and network interdiction applications. These algorithms often employ a technique that divides the decision-making process into a first-stage master problem wherein one set of decisions are determined, after which a set of separable second-stage problems are based on the first-stage decisions. The master problem determines an optimistic assessment of the costs incurred in the second stage; this assessment is then refined by a set of linear functions called cutting planes, which provide cause-and-effect relationships between the first- and second-stage decisions. However, these cutting planes are often ineffective in practical problems. The improvement of these cutting planes is the subject of this proposal. The investigator encountered a surprising feature of some bi-level problems, in which an exponential number of cutting planes may need to be generated at each stage. By reformulating the first-stage problem using slightly more variables and constraints, it was possible to capture all of these cutting planes with a single inequality in the new variable space. Problems that were thought to be impossible to optimality are shown to in fact be solvable within reasonable computational limits.