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Boron and phosphorus implants into germanium and silicon with energies from 20 to 320 keV and ion doses from 5 × 1013 to 5 × 1016 cm-2 were characterized using secondary ion mass spectrometry. The first four moments of all implants were calculated from the experimental data. Both the phosphorus and boron implants were found to be shallower in the germanium than in the silicon for the same implant parameters and high hole concentrations, as high as 2 × 1020 cm-3, were detected by spreading resistance profiling immediately after boron implants without subsequent annealing. Channeling experiments using nuclear reaction analysis also indicated high substitutional fractions (∼ 19%) even in the highest dose case immediately after implant. A greater straggle (second moment) is, however, observed in the boron implants in the germanium than in the silicon despite having a shorter projected range in the germanium. Implant profiles predicted by Monte Carlo simulations and Lindhard-Scharff-schiott theory were calculated to help clarify the implant behavior. Finally, the experimentally obtained moments were used to calculate Pearson distribution fits to the boron and phosphorus implants for rapid simulation of nonamorphizing doses over the entire energy range examined. [ABSTRACT FROM AUTHOR]

The empirical reaction of substitutional carbon with silicon self-interstitials in Si[sub 0.998]C[sub 0.002] layers pseudomorphically grown on Si (100) substrates has been quantified at 850 °C. During annealing of a sample with a thin Si[sub 0.998]C[sub 0.002] layer capped with a thin crystalline silicon layer, in either oxygen or nitrogen ambient, carbon diffuses from the surface edge of the Si[sub 0.998]C[sub 0.002] layer towards and out of the silicon surface. The extra number of carbon atoms lost during oxidation is found equal to the number of silicon interstitials injected by the oxidation process, strongly suggesting that each substitutional carbon reacts with a single self-interstitial to form a mobile interstitial carbon, whereby it diffuses to the surface. The mechanism appears the same in Si[sub 1-x-y]Ge[sub x]C[sub y] and Si[sub 1-x]C[sub x] films. [ABSTRACT FROM AUTHOR]

We examined the effects of both intrinsic neuronal membrane properties and network parameters on oscillatory activity in a model of neocortex. A scalable network model with six different cell types was built with the pGENESIS neural simulator. The neocortical network consisted of two types of pyramidal cells and four types of inhibitory interneurons. All cell types contained both fast sodium and delayed rectifier potassium channels for generation of action potentials. A subset of the pyramidal neurons contained an additional slow inactivating (persistent) sodium current (NaP). The neurons with the NaP current showed spontaneous bursting activity in the absence of external stimulation. The model also included a routine to calculate a simulated electroencephalogram (EEG) trace from the population activity. This revealed emergent network behavior which ranged from desynchronized activity to different types of seizure-like bursting patterns. At settings with weaker excitatory network effects, the propensity to generate seizure-like behavior increased. Strong excitatory network connectivity destroyed oscillatory behavior, whereas weak connectivity enhanced the relative importance of the spontaneously bursting cells. Our findings are in contradiction with the general opinion that strong excitatory synaptic and/or insufficient inhibition effects are associated with seizure initiation, but are in agreement with previously reported behavior in neocortex.

Throughout the 1980s, employers made many health care benefit plan modifications that were directed toward containing costs. This chapter discusses potential managed care program changes that may occur in the coming years. Specifically reviewed are partnerships between employers and managed care entities; possible features of the next generation of managed are plans; and dimensions of a cost-benefit analysis that employers could use to gauge the cost-effectiveness of future plan changes.

CK-3579 (N-[4-[2-hydroxy-3-[[2-[4-(1H-inidazol-1- yl)phenoxy]ethyl]amino]propoxy]phenyl]methanesulfonamide, HCL-[RS]), is a new class III antiarrhythmic agent with beta-adrenoceptor blocking properties shown to be effective in preventing ventricular arrhythmias in experimental animals. We examined the beta 1- and beta 2-adrenoceptor binding properties, cellular electrophysiology, and antiarrhythmic efficacy of CK-3579 and the two enantiomers CK-4000 (S) and CK-4001 (R). Both CK-3579 and CK-4000 were equipotent in displacing [3H]dihydroalprenolol from cardiac membranes (IC50 = 2.4 +/- 0.3 and 1.7 +/- 0.4 microM, respectively) and were approximately 23-59 times more selective for the heart receptor than the lung receptor. The IC50 for CK-4001 at the beta 1-adrenoceptor was 38.1 +/- 8 microM and > 100 microM at the beta 2-adrenoceptor. In isolated canine Purkinje fibers and ventricular muscle preparations, all three compounds increased action potential duration at 95% repolarization (APD95) with equal potency, having an average EC20 of approximately 1 microM in Purkinje fiber and 2 microM in ventricular muscle. No significant effects were observed on any other action potential (AP) parameters. In Purkinje fibers with APs shortened by isoproterenol, the class III activity of CK-4000 was significantly greater than that of CK-4001. CK-4000 inhibits the potassium delayed rectifier current Ik in a concentration-dependent manner in isolated feline ventricular myocytes. The IC50 for inhibition of fully activated current was 0.4 +/- 0.2 microM. Steady-state currents negative to -20 mV were unchanged by CK-4000, but the "hump" in the outward current between -20 and +30 mV was flattened.(ABSTRACT TRUNCATED AT 250 WORDS)

Sematilide (N-[2-(diethylamino)ethyl]-4- [(methylsulfonyl)amino]benzamide HCl) is a new class III antiarrhythmic agent that has been shown to be effective in preventing reentrant ventricular arrhythmias in experimental animals and humans. In this study, we examined the in vitro effects of sematilide (1-100 microM) on isolated sinoatrial (SA) node, atrioventricular (AV) node, and atrial muscle. These results were then compared to another class III agent, clofilium (1-30 microM). In SA nodal tissue, sematilide increased the action potential duration (APD) and spontaneous cycle length (SCL) in a concentration-dependent manner (EC20% = 15 +/- 3 and 54 +/- 13 microM, respectively). In addition, there was a slight reduction in maximum diastolic potential at 100 microM. Clofilium had similar class III effects, but was approximately 3 to 18 times more potent (EC20% = 6 +/- 2 and 3 +/- 1 microM for the APD and SCL, respectively). Neither agent had a significant effect on the slope of phase 4 nor on other action potential parameters. Results in AV nodal preparations were similar. Both sematilide and clofilium increased the APD and SCL in a concentration-dependent manner, with clofilium being approximately four to six times more potent than sematilide (EC20% for the APD and SCL for sematilide = 12 +/- 4 and 12 +/- 8 microM, respectively, and for clofilium = 2 +/- 1 and 3 +/- 2 microM, respectively). No significant effects were observed on other action potential parameters. Sematilide and clofilium increased the APD and effective refractory period (ERP) in atrial trabeculae in a concentration-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Theophylline levels were measured on 63 plasma samples by both high pressure liquid chromatography and Seralyzer methods with excellent correlation. Seralyzer results were obtained quickly and easily in an office setting and offered the additional advantage of allowing accurate measurements on finger-stick samples.

This double-blind parallel group study evaluated ketotifen 1 mg bid versus placebo in the treatment of 30 adult seasonally allergic asthmatics during the course of the spring pollen season. Those individuals on placebo had a fall in FEV1 through the pollen season, those on Ketotifen generally did not, and some individuals, in fact, showed improvement. Those patients receiving ketotifen had fewer allergic symptoms, better exercise tolerance, and in general had a better spring. This study demonstrated that ketotifen may have some benefit in the treatment of adult allergic asthma.

The private health insurance industry collected $55.9 billion in premiums in 1979 and returned $50.2 billion in benefits to its subscribers. Premiums rose 12.4 percent, slightly faster than in 1978 when premiums rose 11.4 percent, to $49.7 billion. Benefits rose 11.4 percent in 1979, down from the 12.6 rate in 1978. After operating expenses were deducted, the industry showed underwriting losses of $1.4 billion in 1979 and $1.5 billion in 1978. About 78 percent of the population was insured for hospital care, 76 percent for x-ray and laboratory examinations, and about 76 percent for surgical services in 1979. Smaller percentages had coverage for other types of care. An estimated 64 percent of the aged bought private hospital insurance, and about 43 percent bought surgical insurance, mostly to supplement Medicare benefits. An estimated 12 percent of persons under age 65 had no protection against the cost of hospital care either through private insurance or a public program such as Medicare or Medicaid.

Twenty-one adult chronic asthmatic patients were studied while taking a 12-hour sustained-action theophylline tablet. Pulmonary function testing and serum theophylline levels were monitored for 12 weeks, including testing every two hours over one dosing interval on the final day of the study. Results indicate the preparation tested produced sustained stable theophylline levels for a full 12 hours, with pulmonary function also remaining elevated and stable during this period. There was minimal toxicity reported over the 12-week period and no evidence of tolerance.

Eighteen patients with chronic urticaria were evaluated concerning the benefit of oral sympathomimetic therapy. No significant differences could be found between the sympathomimetic agent (terbutaline) and a placebo in the various clinical parameters evaluated. The authors conclude that the efficacy of this drug is doubtful in the treatment of chronic urticaria.

The purpose of this study was to compare nebulized terbutaline 5 mg vs. subcutaneous epinephrine (1/1000, 0.3 cc) in the treatment of acute exacerbations of asthma in adult patients. Patients with a known diagnosis of asthma, who presented to the investigators in acute respiratory distress, without any previous adrenergic agents for six hours, were the subjects for this study. There were 33 patients enrolled in the study between 16 and 64 years of age. The results indicate both treatment groups gave significant increases in pulmonary function at all times when compared to baseline (p less than 0.001). Nebulized terbutaline and subcutaneous epinephrine appeared equally effective in the treatment of acute exacerbations of asthma, without significant differences in bronchodilator effectiveness or side effects.

Bioavailability and theophylline level variability were compared between a standard theophylline elixir and a new sustained release theophylline tablet. The results demonstrate a good bioavailability and a reduced dosage interval with less theophylline level variability for the sustained release tablet, administered every 12 hours, than with the immediate release product, every six hours.

This study evaluated the compliance differences between administration of theophylline at six- and 12-hour intervals in a pediatric outpatient population. Compliance was statistically better with the sustained release tablets than with the short acting tablets.

The private health insurance industry collected $47.1 billion in premiums in 1977 and returned $41.6 billion in benefits to their subscribers. Premiums rose 16.3 percent as a direct consequence of rapid claims growth in 1976. After operating expenses were deducted, the industry showed a small, $.4 billion underwriting loss. About 78 percent of the population were insured for hospital care, and about 76 percent for surgical services. Smaller percentages had coverage for other types of care. An estimated 61.8 percent of the aged bought private hospital insurance, and 47.1 percent bought surgical insurance, mostly to supplement Medicare benefits. About 12 percent of persons under age 65 had no protection against the cost of hospital care either through private insurance or a public program such as Medicare or Medicaid.