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To examine differences in race/ethnicity classifications of persons with AIDS among three reporting sources and to estimate the effect of these differences on calculated AIDS rates.We reviewed case reports from the national AIDS surveillance database, interview (self-reported) data from 11 state/local health departments, and death certificate information from 16 state/local health departments for agreement in race/ethnicity coding among persons reported with AIDS.Race/ethnicity coding inconsistencies with AIDS case reports were greatest for persons identified as American Indians/Alaska natives on death certificates (46% [47/102] disagreement) and by self-report (57% 8/14 disagreement). Agreement with AIDS case reports was highest either for persons identified as white from death certificates (4% [1314/31,070] disagreement) and white from self-reports (2% [26/1068] disagreement) or black from death certificates (3% [440/13,592] disagreement) and black from self-reports (3% [21/736] disagreement). For other racial/ethnic groups, disagreement with AIDS case reports was intermediate; for Asians/Pacific Islanders, 12% [45/377] disagreement with death certificates and 33% 4/12 disagreement with self-reports; and for Hispanics, 14% [1151/8527] disagreement with death certificates and 24% [59/249] disagreement with self-reports.For certain racial/ethnic groups, classification by race/ethnicity can differ substantially by surveillance data source. Because allocation of public health resources may be determined by estimates of disease impact on different population groups, periodic evaluations of the accuracy of race and ethnicity reporting are needed to assure appropriate distribution of these resources.

The pharmacological profile of a novel cyclic nucleotide phosphodiesterase (PDE) inhibitor, Org 20241, has been characterized. The compound selectively inhibits PDE IV (pIC50, 5.2-6.1) and PDE III (pIC50, 4.4-4.6) from animal and human tissues. Org 20241 relaxed preparations of bovine trachea (pD2, 5.9 and 5.4), guinea pig trachea (pD2, 6.2 and 4.9) and human bronchi (pD2, 5.3 and 4.7) for histamine and methacholine-induced contractions, respectively. Rolipram and Org 20241 inhibited leukotriene B4-induced thromboxaneB2 (IC50, 0.3 and 1.4 microM, respectively) and H2O2 (IC50, 2.1 and 0.4 microM, respectively) production in guinea pig eosinophils. In phenylephrine (0.3 microM) precontracted rabbit aorta preparations, the PDE III inhibitor Org 9935 (pD2, 6.3 and 6.1 in the presence and absence of endothelium, respectively) was the most effective relaxant, whereas Org 20241 (pD2, 5.3 and 5.4 in the presence and absence of endothelium, respectively) was more effective than rolipram (pD2, 4.6 and 4.1 in the presence and absence of endothelium, respectively). Org 20241 relaxed rabbit aorta preparations and airway preparations at similar concentrations. In electrically stimulated rabbit cardiac papillary muscles, Org 20241 had little effect on contractility at concentrations up to 30 microM. Lower concentrations (10 microM) potentiated the inotropic effect of Org 9935. Whereas the PDE III inhibitor milrinone (1-100 microM) enhanced the rate of repolarization of guinea pig papillary muscles and shortened the effective refractory period, Org 20241 and rolipram (1-100 microM) did not reduce the action potential duration. In the presence of Org 20241 or rolipram, isoproterenol did not produce a greater increase in the rate of repolarization or reduction in the effective refractory period than in the absence of these PDE inhibitors. Org 20241 is a dual PDE IV/III inhibitor with some PDE IV selectively. This compound relaxes airways smooth muscle and inhibits eosinophil activation. The data indicate that such PDE IV/III inhibitors may be effective for the long-term therapy of asthma.

We have previously shown that high dose cortisol (F; 240 mg/day)-induced Na retention and systolic blood pressure (BP) increases are not inhibited by the glucocorticoid (type II) receptor antagonist RU486. Adequacy of type II receptor blockade with RU486 was clearly demonstrated, indicating that the Na retention was not mediated through the glucocorticoid receptor. Spironolactone (Sp; 400 mg/day), in a preliminary assessment, also did not inhibit F-induced Na retention. The purpose of this study was to determine whether the Na retention produced by F administration is mediated by the type I receptor by comparing the effects of F to a potent type I agonist [9a-fludrohydrocortisone (9aFF)] with and without Sp administration. The effects of the two agonists and Sp on urinary K excretion and BP were also compared. Normal male volunteers, on a constant daily diet for 10 days, received either F (240 nig/ day) or 9aFF (3.0 mg/day) with or without Sp (400 mg/day) for the last 5 days. The mean cumulative reductions in Na excretion during the 5 days compared to baseline values before hormone administration were 255 ± 38 and 494 ± 81 mmol/5 days for F (n = 9) and 9aFF (n = 5), respectively (P = 0.01). Sp (n = 5) completely inhibited 9aFF-induced Na retention (494 ± 81 vs. -37 ± 130 mmol/5 days; P < 0.01), but had no effect (n = 5) on F-induced Na retention (255 ± 38 us. 193 ± 50 mmol/5 days; P = NS). After the expected first day kaliuresis, the effects of both steroids on net cumulative urinary K excretion were minimal. Systolic BP was increased by F, but not 9aFF, and Sp did not inhibit this increase. A 2-fold greater Sp-inhibitable Na-retaining effect of the mineralocorticoid demonstrates that the failure of Sp to block F-induced Na retention is not due to inadequate type I receptor blockade. Based on these findings and earlier studies, we conclude that high dose (stress level) Finduced Na retention and systolic BP increase are not mediated by either the mineraloor glucocorticoid receptor in normal man. (J Clin Endocrinol Metab 72: 1060-1066,1991) ORTISOL (F) has mineralocorticoid as well as glucocorticoid effects (1), and it also binds to both type I (mineralocorticoid) and type II (glucocorticoid) receptors in renal cytosol in man (2, 3). However, the effects of F on renal electrolyte excretion are poorly understood. Acute administration of F variably produces either natriuresis or Na retention, but always kaliuresis; these changes may be associated with an increase in the glomerular filtration rate (GFR) (1). Comparison of the renal effects of F to those of more potent synthetic glucocorticoids has led to the conclusion that the increased GFR, acute kaliuresis, and associated natriuresis are glucocorticoid effects (1, 4-6). The Na-retaining Received October 2,1990. Address requests for reprints to: C. O. Watlington, M.D., Endocrine Division, Department of Medicine, MCV Station, Box 145, Richmond, Virginia 23298-0145. * This work was supported by NIH Grants R01-DK-35341 and R01DK-36822, Clinical Research Center Grant RR-00065, and a Grant-InAid from the A. D. Williams Foundation. t Postdoctoral fellow supported by NHLBI Training Grant HL07110. $ Recipient of a Clinical Associate Physician Award from the NIH. effects of F, more clearly demonstrable after the first 12 h of administration (5), are considered to be mediated by renal type I receptor activation (7). We have recently described the effects of RU38486 (RU486), a potent type II receptor antagonist, on the changes in urinary Na and K excretion produced by high dose F over a 5-day period in normal man (8). Despite ample evidence for adequate glucocorticoid blockade, RU486 did not alter F-induced urinary Na retention. These studies suggested that the Na retention was not mediated by type II receptors. Administration of the type I receptor antagonist spironolactone (Sp) at a dosage of 400 mg/day also did not inhibit F (240 mg/ day)-induced Na retention and only blunted a lesser effect produced by a lower dosage (120 mg/day). These findings raised the possibility that high dose F produces Na retention by a mechanism mediated by neither type I nor type II receptor activation. However, the evidence for adequacy of type I receptor blockade was not definitive (see Discussion). The present study was designed to determine whether F-induced Na retention is mediated

Studies in humans have shown that cortisol administration (200 mg/day) increases cardiac output, renal vascular resistance, glomerular filtration rate, plasma volume, extracellular fluid volume, exchangeable sodium, plasma glucose, insulin, renin substrate and atrial natriuretic peptide concentrations as well as urinary kallikrein excretion. Cortisol treatment decreases renin and angiotensin II concentrations while catecholamines and vasopressin are decreased or unchanged. We have clear evidence from a number of studies that cortisol-induced hypertension is modulated by, but not dependent on, exogenous sodium. The increase in cardiac output normally seen with cortisol administration is not essential for the blood pressure rise. The role of the increase in renal vascular resistance in the genesis of the hypertension is unclear. Studies using measurements of noradrenaline spillover and assessment of reflex function have not shown any increase in sympathetic nervous system activity but changes in vascular responsiveness, particularly to phenylnephrine and noradrenaline are marked. Cortisol is known to have a variety of effects on brain, heart, kidneys, blood vessels and body fluid volumes. To what extent the observed changes are epiphenomena, amplifiers or modulators, or are causal is unclear. Cortisol hypertension may reflect a complex interplay of these factors varying with the steroid concentrations achieved, underlying genetic factors and the particular experimental circumstances.

Ethical concerns exist over the performance of medical procedures, such as endotracheal intubation, on newly deceased patients without family consent. This study examined the process of obtaining consent for the purpose of performing an invasive procedure in newly deceased adults.A prospective case series.The families of patients who died during a 5-month period were requested to provide consent to perform wire-guided retrograde tracheal intubation.Differences between success and failure in obtaining consent including information on the decreased, family reasons for their decision, and the experience of those requesting consent.Consent was requested from 44 families and 26 (59%) agreed to the procedure. This success rate was achieved despite the lack of a prior relationship with the family by the persons requesting consent. Consent was obtained more frequently in unexpected than expected deaths (77% vs 41%, P = .03). There were no differences in success rates for consent for age, race, sex, or do-not-resuscitate status of the deceased. Spouses consented more frequently than children (77% vs 50%, P = .25). The two physicians reported greater comfort in requesting consent than the nurse anesthetist investigator. In one instance, the consent process may have increased the emotional distress of the family.Consent can frequently be obtained from families for an invasive procedure in newly deceased adults. Physicians should reconsider the practice of performing postmortem procedures without obtaining family consent.

The purpose of this study was to determine differences in the use of total knee arthroplasty for osteoarthritis among black and white older Americans and to determine whether clinical and economic factors contribute to these differences. Data on black and white Americans aged 65 years and older were gleaned from national Medicare hospitalization records for 1980 through 1988 and the Medicare enrollment file for 1987, the First National Health and Nutrition Examination Survey of 1971 through 1975, the National Hospital Discharge Survey of 1979 through 1988, the 1980 through 1988 US census counts and estimates, and 1980 census economic data. Information gathered includes prevalence of osteoarthritis of the knee among blacks and whites; rate of total knee arthroplasty use in the United States by race, sex, and age of subjects at the time of operations; use of competing procedures; and economic factors. Results showed that blacks were less often treated with total knee arthroplasty than were whites (white-to-black rate ratios = 3.0 to 5.1 for men and 1.5 to 2.0 for women) but had nonsignificantly higher rates of clinical osteoarthritis of the knee (white-to-black rate ratios = 0.39 for men and 0.78 for women). This racial difference in total knee arthroplasty rates was consistent across income levels and was unexplained by black patients' having operations at earlier ages or using competing procedures. Furthermore, the discrepancy occurred even among Medicaid-eligible Medicare recipients, who had no direct economic disincentive for surgery. These findings suggest that even though elderly blacks have higher rates of knee osteoarthritis, they do not receive total knee arthroplasty as often as do elderly whites. This discrepancy does not appear to have an economic explanation. Even if a comprehensive care system were in place to remove economic barriers, inequality in the use of this procedure would likely persist. Future studies should assess the nonclinical and noneconomic causes of these differences.

Medicare records represent a potential resource for surveillance data on hospitalizations among the elderly. Several features make these data useful for describing hospitalization patterns: a) Medicare covers hospitalization expenses for approximately 95% of the U.S. population greater than or equal to 65 years, and these data are considered to represent accurately the hospitalization patterns of this group; b) The comprehensive nature of the information about the beneficiary population provides public health researchers with data to generate accurate rates for well-defined demographic and geographic subgroups; c) Because data for all covered hospitalizations have been included in the file since 1984, stable estimates for even relatively rare conditions can be generated for any years since then; d) A unique personal identifier on each record permits the differentiation of first from subsequent hospitalizations, thereby permitting public health researchers to generate both counts and rates of hospitalizations by person and by event; and e) Temporal trends in hospitalization can be generated for 1980 through 1988, because data are available in machine-readable form. This report presents surveillance data for elderly persons hospitalized in 1988 for several diseases of public health importance. In 1988, approximately 9.1 million hospitalizations covered by Medicare occurred among persons greater than or equal to 65 years. For major disease categories, the rates of persons discharged ranged from 7,448/100,000 for circulatory diseases to 274/100,000 for blood diseases. For the 49 discrete diseases and conditions studied, rates varied widely by gender, race, and age. Conditions also varied widely in the mean number of discharges per person and in the probability that the condition would be recorded as the principal diagnosis.

Purpose It is thought that a substantial number of patients who undergo anti-reflux surgery use anti-reflux medication post operatively, despite no objective evidence of reflux. This study aims to determine the prevalence and underlying reasons for anti-reflux medication usage in patients after anti-reflux surgery. Methodology A questionnaire (13 questions) on the usage of anti-reflux medication was sent to 1016 patients from a prospective database of anti-reflux surgery patients. Results 852 patients (84%), (437 males & 415 females with a mean age 58 yrs) returned the questionnaire. Mean follow up was 5.9 yrs after surgery. A single or combination of medications was being taken by 319 patients (37%): 82% proton pump inhibitors, 9% H2-blockers and 34% antacids. 54 patients (18%) had never stopped taking medication, whereas 261 patients (82%) re-started medication at a mean of 2.4 yrs after surgery. Persistent or return of the same or different symptoms was the reason for taking medication by the vast majority (85%), whereas 15% were asymptomatic or had other reasons for medication use. A response of symptoms to the medication occurred for 30% of the patients, whereas 64% noticed some improvement. Postoperative 24-hour pH studies (while off medication) were abnormal in 17/62 patients (27%) on medication and in 5/73 patients (6%) not taking medication. Conclusions Anti-reflux medication is frequently taken by patients for symptoms after surgery, despite normal pH profiles in the majority. Strategies need to be employed to lower the inappropriate use of medications after surgery and to further evaluate the mechanisms underlying postoperative symptoms, which are non-responsive to anti-reflux medication.

A process has been developed for the electrodeposition of a high strength, heat resistant Ni-Mn alloy for high aspect ratio microstructures (HARMST). A conventional Ni sulfamate electrolyte is employed with the addition of a small amount of manganese chloride. The deposits are low stress (< ∼ 60 MPa tensile), enabling the deposition of thick section films required for HARMST. The Mn content for the alloys of interest is less than about 1 wt %, and its codeposition is insensitive to mass-transport effects, permitting uniform alloy deposition, regardless of feature aspect ratio. A pulsed deposition scheme is employed to fabricate a nanostructured film consisting of alternating nanometer thick regions of relatively pure Ni, and hard, Mn-rich Ni; this moderates the high stress of the NiMn alloy and enables the deposition of thick deposits. Yield strengths of over 800 MPa are achievable, with good as-plated ductility (∼6%). The material loses only about 15% of its original strength after a 1 h, 600°C anneal, and no embrittlement is observed since no S-bearing additives are employed.

To the Editor: Burns et al. reviewed clinical neurophysiology (CNP) training in the United States.1 Since the approval of CNP as an added qualification examination and the establishment of CNP fellowships, EMG and EEG training have changed. We agree that there is limited exposure to CNP during residency and that additional training is often required. However, as currently structured, we believe CNP training has become too diluted, creating CNP generalists rather than focused experts, as was the case formerly. Burns et al. acknowledge that CNP training is not designed to make experts in each CNP area, but rather provides greater knowledge and skill than obtained during residency. One might ask where future EMG and EEG experts will come from, if not from CNP fellowships. The majority of residents pursuing fellowship training still do so in preparation for an academic career.2 It would appear unlikely that many candidates will opt for training beyond one additional fellowship year. We have had the opportunity to train fellows in 6-month, 12-month, and 2-year programs devoted solely to EMG/neuromuscular disorders. The largest growth in expertise occurs between 6 and 12 months, when fellows consolidate their knowledge, increase their confidence and procedural skills, and solve difficult problems independently. As currently structured, EMG training is particularly handicapped in CNP fellowships, because the equivalent of 12 months EMG training cannot …

Scanning and transmission electron microscopy ITEM) were used to characterize the microstructure of electrodeposited multilayer Cu-Co alloys. Both columnar alloys (where the Co is localized to the columns) and three-dimensional arrays (where the Co is present in regions less than 1 μm diam) were studied. The latter type was produced by successively electrodepositing a columnar alloy layer between Cu spacer layers, resulting in a semiordered, three-dimensional network of Co-rich regions in a principally Cu matrix. The composition gradient between the Co-rich regions and the Cu matrix was verified by electron energy loss spectroscopy and energy-dispersive spectroscopy using TEM. It was found that the size of the Co-rich regions was affected more by the overall alloy layer composition than by the deposition parameters. Under appropriate conditions, it was possible to reduce the individual alloy layer thickness to 25 nm while maintaining chemical segregation between the Co-rich areas. Annealing at 250°C and higher caused the Co-rich regions to merge together.

The effects of two additives, sodium dodecyl sulfate (SDS) and saccharin, on the composition and microstructure of pulse-plated Cu-Co alloys have been studied. The additive SDS appears to promote the displacement of Co by Cu during pulse off-times in the pulsed deposition of Cu-Co alloys. For short pulse periods, films made with SDS only are composed of Co-rich columns surrounded by a Cu-rich matrix phase. Films made with both SDS and saccharin at short pulse periods are face-centered cubic in orientation with a grain size of about 10-15 nm. The interfacial planarity of laminated films produced at longer pulse periods is improved by saccharin. By taking advantage of the self-organizing Co-rich columns obtained at short pulse periods and using Cu spacer layers, it is possible to obtain three-dimensional arrays of Co-rich nanophases using a single electrolyte and no masking of lithographic processes.

A rotating quartz crystal microbalance is employed to study the effects of the additives sodium dodecyl sulfate (SDS) and saccharin during the pulsed deposition of Cu-Co alloys. SDS promotes Co displacement by Cu during pulse off-times, while saccharin impedes this process. On-time current efficiencies for pulsed deposition are lower than those during dc deposition, particularly for SDS-only electrolytes. Off-time areal mass increases in SDS-only electrolytes are much larger than those expected from the displacement of Co by Cu and exhibit a square root dependence on the electrode rotation rate; other electrolytes do not display this behavior. Assuming these mass increases are due to SDS incorporation yields inclusion densities that are consistent with other metal/additive systems previously characterized in the literature. The interaction of SDS and saccharin during pulsed deposition is discussed.

The impedance characteristics for redox reactions involving minority carrier recombination at semiconductor electrodes differ markedly from those involving majority carriers. In this work, holes were generated in the valence band ofn-GaAs by illumination or injection from solution. A recombination resistance is used to characterize the process bywhich these holes recombine with electrons from the conduction band. This resistance is shown to be independent ofthe method of hole generation, the pH of the solution, and the nature of the injecting species, but dependent on the generation rate.

The modified Enskog theory of van Beijeren and Ernst for dense fluid mixtures of rigid spheres is applied to diffusion of inert, nonadsorbing gases in microporous “leaky” membranes. Utilizing the concept of a dense dusty gas, the resulting expressions for the permeability and flux ratio illustrate the influence of steric hindrance on the transport process. The results obtained serve as corrections to the original dusty gas model of Mason and others.

This paper deals with the response of an infinite elastic cylinder to simple exterior acoustic sources (monopole and dipole). A coupled solution involving spectral equations of motion is used to evaluate the parameters of interior pressure, power flow into the cylinder, and variation of acoustic intensity with angular position at the cylinder wall. The variation of these parameters with source characteristic and location as well as observation point is investigated in order to uncover the nature of the interaction phenomena. In general, the interior pressure was found to fall quickly for an initial increase in source location and then more slowly. Dipole sources were also found to excite far lower interior sound levels than monopoles. The results are of use in leading to an understanding of the interaction of propeller acoustic sources with aircraft fuselages.

A coupled waveguide model is developed that represents sound transmission in a flowing fluid which contains a windscreened microphone probe. The flow is contained in an outer annular region of a circular section duct. In the central region the fluid is quiescent, and these two regimes are separated by a porous windscreen concentric with the duct. This windscreen is characterized by a specific flow resistance R. Acoustic coupling occurs across the windscreen and the central region represents the probe where the acoustic quantities are to be measured. The use of modal theory permits this situation to be formulated as an eigenvalue problem which results in an appropriate dispersion relation. Solving this equation analytically is quite difficult since the eigenvalues are complex. An alternative approach is to solve the governing equation for the acoustic pressure numerically. With these pressure profiles an iteration process is devised, in which an optimization technique is used, to determine the wavenumbers and attenuation rates.

The contribution of electron excitation to the anodic dissolution of the n-GaAs electrode was studied quantitatively by measuring the increase in the anodic blocking current when hole-injecting agents such as Ce4+ or Fe(CN)3−6 were added to the electrolyte solution. The experimental relationship between the anodic current and the cathodic hole injection current was interpreted on the basis of the anodic decomposition mechanism, including a chemical step, proposed previously to explain stabilization results. This mechanism is complemented by an electrochemical step involving electron excitation from a decomposition intermediate occurring in parallel to the chemical step.

For various technological applications patterns are chemically etched in metal films partly covered with a nobler metal. As a result of the bimetallic contact, accelerated etching may occur, giving rise to considerable undercutting. From electrochemical considerations it was expected that the use of certain chemical polishing solutions would significantly reduce the degree of such undercutting. This was verified by studying the electrochemical properties of various polishing and nonpolishing etching agents. Suitable solutions were developed for the etching of Al, Mo, and Ni‐P. These etching agents, when used to etch metal films partly covered by nobler metals, gave markedly less undercutting than nonpolishing etching agents.

The manner in which a series of silcarboranylene–siloxane polymers behave in air at elevated temperatures was investigated by thermogravimetric, isothermogravimetric, and differential thermal analyses techniques. Results indicate that methyl pendant groups on the polymers undergo thermal and oxidative degradations at temperatures under 600°C. Final weight losses of the polymers, however, are significantly lower than that shown by dimethylsiloxanes. The reduced volatility is attributed to the inhibition of thermooxidation by the m-carboranylene group in the polymer molecules. This protective influence decreases apparently as the distance between the carborane nucleus and the methyl groups increases.

The novel inorganic polymer poly(aquahydroxychromium diphenylphosphinate) was investigated to obtain information concerning its degree of polydispersity and properties when dissolved in organic solvents. Viscometric, infrared absorption spectroscopic, and electrical conductimetric techniques were employed to ascertain the characteristics of the polymer dissolved in benzene, chlorobenzene, and chloroform. Gel permeation chromatography was used to determine the degree of heterogeneity of the polymer. Results indicate that the polymer, as prepared, is quite polydisperse. The polymer main chains do not undergo radical reactions with the solvents. High values of the Huggins interaction constant K′ suggest that polymer–solvent association reactions involving chain-endgroups are probable. Such reactions are also indicated by association constant values and by the shapes of phoreograms obtained from electrical conductance data. Both “local” and “bulk” solvent properties, such as the dielectric constant, appear to influence the characteristics of the polymer when dissolved in the different solvents.

1. Cases are presented to show that blackthorn inflammation is not uncommon in the West Midlands. 2. The pathology is that of a chronic non-suppurative inflammation. 3. Cases are divisible into three groups on the basis of their history. In the third group, with no history of blackthorn trauma, diagnosis may be very difficult. 4. Removal of the blackthorn fragments causes prompt resolution of the inflammation.

Investigations regarding the influence of temperature on the shape of ice crystals, grown at water saturation, were carried out in a room-size cold chamber. It was found that the principal shape of the ice crystals—i.e., column- and plate-like forms—alternate with decreasing temperature, and that the mechanism of ice crystal formation is apparently more complicated than existing theories and previous experiments indicate.

These studies were undertaken to determine the thermal behavior of structurally related polymers having a carborane nucleus in the recurring unit. Three of these products also contained phthalocyanine rings in their molecules. Results of thermal analysis studies show generally that the relative heat stability of the polymers conforms closely with indications given by similar investigations of structurally related intermediate and model compounds. A polymer with dimethylsiloxane units exhibited more resistance to thermal decomposition than similar products having urethane groups in their molecules. The urethane polymers derived from tolylene diisocyanate were found to be somewhat less heat-stable than analogous materials synthesized from methylenebis-(p-phenyl isocyanate). The relative order of thermal resistance of these materials follows that of more conventional polyurethane elastomers.

Polysiloxanes containing carboranylbutyl and methyl pendant groups were investigated, to determine their resistance to thermal decomposition when heated in air. Results indicate that the copolymers degrade through SiC as well as SiO bond rupture. At 300°C. thermooxidative scission of pendant groups was the predominant reaction. whereas SiO and SiC bond rupture occurred at 500°C. Variations in the behavior of the copolymers studied suggest that the carborane nucleus provides some inhibiting influence on their thermal decomposition. This is mainly attributed to steric hindrance effects rather than polarity factors. Chain extension with tin octoate caused a reduction of thermal stability, probably because of the addition of SnO bonds to the molecules.

This paper deals with the response of an infinite elastic shell to simple acoustic sources (monopole and dipole). This simplified model is considered in order to gain insight into the characteristics of aircraft interior noise. The shell represents the aircraft fuselage and the sources are due to the propellor. Specifically, in this study the location of the source with respect to the cylinder is the major concern. How this affects acoustic line power, intensity flow into the shell and internal sound pressure is analyzed.

Die zu der grosen Uberspannung in bezug auf das fur das Einsetzen des Photostroms (Hz-Entwicklung und bestimmte Redox-Reaktionen) erforderliche Flachbandpotential beitragenden Faktoren an belichteten p-leitenden Elektroden aus III-V-Verbindungen wie GaAs, GaP, InP werden untersucht.

A report is given summarizing Union Carbide Corporation-Nuclear Division's (UCC-ND's) composite flywheel program objectives and accomplishments for the period from May 1 through June 30, 1976. The necessity and urgency of national energy conservation is a well-recognized fact. Mechanical-energy storage, using rotating flywheels, is one of the few known methods for energy storage, and flywheels probably have the highest potential effectiveness for energy storage of any method now available. Initial application selected for the development of the composite flywheel is the heat engine/flywheel hybrid propulsion system for a vehicle, because of its high potential for the conservation of petroleum fuel in both the near and long-range time frames. Efforts have focused into key areas consistent with its experience base: state-of-the-art flywheel development, spin testing, and containment development. An operating performance goal of 20 watt-hr/lb (20 Wh/lb) energy density at an energy level of 0.56 kWh has been set by UCC-ND. The 20 Wh/lb goal encompasses both the composite flywheel and the hub that connects it to the shaft. It does not include the shaft. The goal exceeds the present performance of isotropic flywheels, and is also at the upper limit of current laboratory technology reported in the literature for compositemore » flywheels. The thick rim with radial overwrap bands was selected as the initial design concept. Kevlar-49/epoxy was selected as the construction material, and the end of the design phase is near. A process for fabricating full-scale Kevlar-49/epoxy thick rims was developed, and full-scale rims were successfully wound. More detailed information is presented on the development plan for this budgetary period, and the present accomplishments with respect to: (1) flywheel design, analysis, and fabrication and (2) spin testing are discussed.« less

Aus einer Untersuchung der Kinetik der Locherinjektion von oxidierenden Agentien in Losung in das Valenzband des p-GaAs (cyclisch voltammetrische und Potentialsprungmessungen) geht hervor, das sich das Helmholtz-Potential der Elektrode bei Potentialen nahe dem Flachbandwert signifikant andert.

To determine the clinical and hemodynamic changes associated with aortofemoral bypass, 44 limbs of 31 patients underwent segmental plethysmography (PVR) and Doppler pressures (DSP) before operation, immediately after operation, and again at 6 months. Prior to operation patients were separated by angiographic criteria into two groups: aortoiliac segment disease alone (AI) (n = 22), and aortoiliac and femoropopliteal segment disease (AIFP) (n = 22). At 6 months the two groups were subdivided into four groups based on relief (oSx) or lack of relief (+Sx) of symptoms. Before operation the only significant difference between the four groups was a higher thigh PVR and calf DSP in the AI + Sx group. Six month PVR values in AIoSx were improved nearly twofold over preoperative measurements at the thigh and calf, but at the thigh level only for AIFPxSx. DSP was increased at all three levels in both AI and AIFPoSx groups. No hemodynamic improvement occurred in either the AI or the AIFP + Sx groups. A derivative index of PVR (thigh-ankle/15 mm) or the FPomega was significantly lower in AIFOsSx before operation. There was a significant disparity between classification by hemodynamics and by symptoms prior to operation which lessened somewhat after operation. These studies suggest that success or failure can be predicted before operation in AIFP by FPomega, and arterial disease should be classified by a combination of symptoms, angiography, and hemodynamics.

Aortofemoral (AF) and axillofemoral bypass grafts (AXFG) are alleged to have similar patency rates, but little is known of their comparative functional results. In 91 limbs clinically selected for AXFG or AF, pulse volume recording amplitude (PVR) and Dopper systolic ankle/brachial artery pressure ratio (DSP A/B) were measured before and 6 months after surgery. Preoperatively, the limbs were classified by angiography into aortoiliac disease alone (AI) or AI and femoropopliteal disease (AIFP), and were further classified by PVR and DSP A/B into claudication and limb salvage groups. Six months after surgery, the degree of hemodynamic improvement was comparable for AF and AXFG for limbs with AI. After AXFG in AIFP, however, the claudication group showed less of an improvement in DSP A/B ratio and PVR than with AF. There was no functional improvement after AXFG in the limb salvage group. AF appears to be associated with better functional results than AXFG in AIFP.

"This article seeks to highlight the extent of the lack of standardization which exists in the field of international migration statistics and, using statistics for Canada as an example, to illustrate how significant progress towards resolving this problem could be made if sufficient numbers of countries made their immigration and emigration statistics gradually comply more fully with the United Nations recommendations."

Sera from 10 patients with AIDP and 10 age-matched controls were microinjected into the tibial division of rat sciatic nerve using improved microinjection techniques and coded sera. No statistically significant changes in conduction velocity or amplitude of the compound muscle action potential (CMAP) or in the monophasic compound action potential (CAP) parameters was found at 1 week. In nerves studied with serial recording over 1 h a small but significantly greater reduction in CMAP amplitude was observed at 60 min in the AIDP group and at both 30 and 60 min when only sera from very severely affected (bed-ridden) patients were considered. A similar reduction was found following microinjection into focally demyelinated nerves. The finding of a small reduction in CMAP amplitude in the first hour suggests the presence in some AIDP patients of serum blocking or demyelinating factors but the clinical significance of this small reduction is uncertain.