4,176 research outputs found
The atom-molecule reaction D plus H2 yields HD plus H studied by molecular beams
Collisions between deuterium atoms and hydrogen molecules were studied in a modulated crossed beam experiment. The relative signal intensity and the signal phase for the product HD from reactive collisions permitted determination of both the angular distribution and HD mean velocity as a function of angle. From these a relative differential reactive scattering cross section in center-of-mass coordinates was deduced. The experiment indicates that reactively formed HD which has little or no internal excitation departs from the collision anisotropically, with maximum amplitude 180 deg from the direction of the incident D beam in center-of-mass coordinates, which shows that the D-H-H reacting configuration is short-lived compared to its rotation time. Non reactive scattering of D by H2 was used to assign absolute values to the differential reactive scattering cross sections
TB83: Insecticidal Control of Potato Infesting Aphids in Northeastern Maine
Aphid populations for the growing seasons of 1970, 1971, and 197 2 were variable. It is possible, however, to rate the efficacy of the various insecticides tested in controlling potato-infesting aphids in northeastern Maine. Soil applications of aldicarb and DS 15,647 and foliar application of acephate were the most effective materials tested. The insecticides phosmet (foliar) and phoxim (soil) did not provide much protection against potato-infesting aphids in these tests. Bayer 77,049, parathion, Penick SBP 1382, Sandoz-Wander 52,139 and Uniroyal 840 did not provide effective control of potato-infesting aphids at the rates used in these tests. All other insecticides tested adequately controlled aphid populations, but their effects on the spread of leaf roll varied. Some of the materials tested were experimental materials and not all are available for commercial use.https://digitalcommons.library.umaine.edu/aes_techbulletin/1112/thumbnail.jp
Obstetric and long-term kidney outcomes in renal transplant recipients: a 40 year single-centre study
Female renal transplant recipients of childbearing age may ask what the outcomes are for pregnancy and whether pregnancy will affect graft function. We analyzed obstetric and transplant outcomes among renal transplant recipients in our center who have been pregnant between 1973 and 2013. A case−cohort study was performed identifying 83 pairs of pregnant and non-pregnant controls matched for sex, age, transplant vintage, and creatinine. There were 138 pregnancies reported from 89 renal transplant recipients. There were live births in 74% of pregnancies with high prevalence of prematurity (61%), low birth weight (52%), and pre-eclampsia (14%). Lower eGFR (OR 0.98; p = 0.05) and higher uPCR (OR 1.86; p = 0.02) at conception were independent predictors for poor composite obstetric outcome. Lower eGFR (OR 0.98; p = 0.04), higher uPCR (OR 1.50; p = 0.04), and live organ donation (OR 0.35; p = 0.02) were predictors of ≥20% loss of eGFR between immediately pre-pregnancy and one yr after delivery. There was no difference in eGFR at one, five, and 10 yr in pregnant women compared with non-pregnant controls and a pregnancy was not associated with poorer 10-yr transplant or 20-yr patient survival. Despite high rates of obstetric complications, most women had successful pregnancies with good long-term transplant function
Theoretical Advantages of Abdominal Counterpulsation in CPR as Demonstrated in a Simple Electrical Model of the Circulation
Animal studies and preliminary clinical observations suggest that the addition of interposed abdominal compressions (IAC) to ventilation and chest compression of standard cardiopulmonary resuscitation (CPR) augments blood flow, blood pressures, and immediate survival. To investigate the physical basis for enhanced circulation during IAC-CPR, we developed an electrical model of the circulation. Heart and blood vessels were modeled as resistive-capacitive networks, pressures as voltages, blood flow as electric current, blood inertia as inductance, and the cardiac and venous valves as diodes. External pressurization of the heart and great vessels, as would occur in CPR, was simulated by application by half-sinusoidal voltage pulses between vascular capacitances and ground. Closed-chest CPR was simulated by pressurization of all intrathoracic capacitances. IAC was simulated by similar pressurization of the inferior vena cava and abdominal aorta, 180 degrees out of phase with chest compression. During simulation of CPR, IAC improved cranial and myocardial perfusion at all levels of chest compression pressure by amounts linearly related to peak abdominal pressure, suggesting that the abdomen can function as a second, independent blood pump during CPR. Brain and heart flow were improved further during simulated vasoconstriction in kidneys, abdominal viscera, and extremities. Based on the fundamental properties of the cardiovascular system represented in the model, abdominal counterpulsation provides a rational basis for flow augmentation during CPR
TB57: Effects of Cultural Methods for Controlling Aphids on Potatoes in Northeastern Maine
A study was conducted at Aroostook Farm, near Presque Isle, Maine, 1954 to 1958, inclusive, to determine the effects of certain agronomic cultural practices designed to delay emergence of potato plants and to decrease their exposure to infestation by spring migrants. This technical bulletin reports the results of that study.https://digitalcommons.library.umaine.edu/aes_techbulletin/1130/thumbnail.jp
TB52: Seasonal Population Trends and Productiveness of the Potato Aphid on Swamp Rose in Northeastern Maine
Studies were conducted in northeastern Maine to determine seasonal population trends and productiveness of the potato aphid on swamp rose. The results presented and discussed concern chiefly chronological and phenological aspects of the utilization of swamp rose as a primary host of the aphid; time-temperature developmental requirements of the aphid in spring; productiveness of the aphid in caged colonies on swamp rose in spring; population trends of the aphid on naturally occurring, undisturbed swamp rose in spring and in fall; populations of aphid eggs on swamp rose in November and again in mid-April of the following year; and a comprehensive assessment of the probable usefulness of results from surveys of abundance of the aphids or aphid eggs on swamp rose in making advanced estimates of abundance of the potato aphid on potatoes.https://digitalcommons.library.umaine.edu/aes_techbulletin/1147/thumbnail.jp
TB39: Canada Plum, Prunus nigra Aiton, as a Primary Host of the Green Peach Aphid, Myzus persicae (Sulzer), in Northeastern Maine
Studies were conducted to determine the role of Canada plum as a host of the green peach aphid in northeastern Maine and to assess its importance as a source of infestation by the aphid on potatoes. The results relate chiefly to chronological and phenological aspects of the use of Canada plum as a primary host of this aphid; temperature developmental requirements of the aphid on this plant in spring; productiveness of spring migrants of the aphid in thickets and in cages; interrelationships between fall aphid populations on foliage, and egg deposition and overwintering to naturally occurring aphid colonies in spring and summer populations on potatoes.https://digitalcommons.library.umaine.edu/aes_techbulletin/1156/thumbnail.jp
Cardiac, Thoracic, and Abdominal Pump Mechanisms in Cardiopulmonary Resuscitation: Studies in an Electrical Model of the Circulation
To investigate alternative mechanisms generating artificial circulation during cardiopulmonary resuscitation (CPR), an electrical model of the circulation was developed. Heart and blood vessels were modeled as resistive-capacitive networks; pressures in the chest, abdomen, and vascular compartments as voltages; blood flow as electric current; blood inertia as inductance; and the cardiac and venous valves as diodes. External pressurization of thoracic and abdominal vessels, as would occur in CPR, was simulated by application of half-sinusoidal voltage pulses. Three modes of creating artificial circulation were studied: cardiac pump (CP), in which the atria and ventricles of the model were pressurized simultaneously; thoracic pump (TP), in which all intrathoracic elements of the model were pressurized simultaneously; and abdominal pump (AP), in which the abdominal aorta and inferior vena cava of the model were pressurized simultaneously. Flow was greatest with the CP, less with the TP, and least with the AP mechanism. However, the AP could be practically combined with either the CP or TP by interposition of abdominal compressions between chest compressions (IAC-CPR). Our model predicts that this combined method can substantially improve artificial circulation, especially when cardiac compression does not occur and chest compression invokes only the thoracic pump mechanism
Clinical importance of cystic fibrosis-related diabetes
AbstractThe prevalence of cystic fibrosis-related diabetes (CFRD) and glucose intolerance (IGT) has risen dramatically over the past 20 years as survival has increased for people with cystic fibrosis (CF). Diabetes is primarily caused by pancreatic damage, which reduces insulin secretion, but glucose tolerance is also modified by factors that alter insulin resistance, such as intercurrent illness and infection. CFRD not only causes the symptoms and micro and macrovascular complications seen in type 1 and type 2 diabetes in the general population, but also is associated with accelerated pulmonary decline and increased mortality. Pulmonary effects are seen some years before the diagnosis of CFRD, implying that impaired glucose tolerance may be detrimental.Current practice is to screen for changes in glucose tolerance by regular measurement of fasting blood glucose, by oral glucose tolerance test or a combination of these approaches with symptom review and measurement of HbA1C. Treatment is clearly indicated for those with CFRD and fasting hyperglycaemia to control symptoms and reduce complications. As nutrition is critical in people with CF to maintain body mass and lung function, blood glucose should be controlled in CFRD by adjusting insulin doses to the requirements of adequate food intake and not by calorie restriction. It is less clear whether blood glucose control will have clinical benefits in the management of patients with CFRD without fasting hyperglycaemia or with impaired glucose tolerance and further studies are required to establish the best treatment for this patient group
TB19: Parasites of Potato-Infesting Aphids in Northeastern Maine
This publication presents brief synopses of the biology of several of the more common species or genera of primary parasites and of hyperparasites occurring in northeastern Maine. Three approaches are discussed for increasing effectiveness of insect parasites against the potato-infesting species of aphids, including (1) the introduction of new species of parasites or strains of species better adapted and more effective against each species of aphid than the naturally occurring ones, (2) the mass releasing of parasites in potato fields at times critical for the population dynamics of the aphids, and (3) a combination of these. The combined-effort approach is considered most likely to succeed.https://digitalcommons.library.umaine.edu/aes_techbulletin/1179/thumbnail.jp
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