Collisional ionization and recombination in degenerate plasmas beyond the free-electron-gas approximation.

One of the most successful ways to model the multitude of electron and photon processes in plasmas is the approach used in collisional radiative (CR) codes. The accuracy of CR codes depends largely on the accuracy of the rates of each process. These rates are generally well approximated in hot, classical plasmas. However, in degenerate plasmas quantum effects can influence these rates and must be accounted for. Previous approaches have developed corrections to the classical rates using the free-electron-gas (FEG) approximation. Here, we use electronic structures beyond the FEG approximation and show how the collisional rates are affected by degeneracy in aluminum and iron plasmas. We find that the FEG is a good approximation for aluminum, whereas more complex electronic structures that include d orbitals, such as iron, deviate from the FEG approximation. This results in different degeneracy corrections to the collisional rates relative to those for the FEG. Although the general trend of the corrections to degenerate plasmas is captured by assuming an FEG, we show that more complex electronic structures can result in deviations, even outside the degenerate regime. This study further advances the treatment of free-electron quantum effects in collisional radiative models.

Shot-to-shot intensity and wavefront stability of high-harmonic generation.

We report on the shot-to-shot stability of intensity and spatial phase of high-harmonic generation (HHG). The intensity stability is measured for each high-harmonic (HH) order with a spectrometer. Additionally, the spatial phase is measured with an XUV wavefront sensor for a single HH order measured in a single shot, which according to our knowledge was not reported before with a Hartmann wavefront sensor. Furthermore, we compare the single-shot measurement of the spatial phase with time-integrated measurements and we show that the XUV wavefront sensor is a useful tool to simultaneously optimize the spatial phase and intensity of HHG within the available HHG parameter range used in this study.

The role of misorientation and phosphorus content on grain growth and intergranular fracture in iron-carbon-phosphorus alloys.

The relationship between the crystallography of intergranular fracture and phosphorus segregation has been investigated in a Fe-0.06wt%P-0.002wt%C alloy aged for 1 h at temperatures between 600 degrees C and 1000 degrees C. Two novel techniques were devised for the investigation: first, electron back-scatter diffraction (EBSD) across the reconstructed fracture surface and, second, a combination of Auger electron spectroscopy, stereophotogrammetry and microscopy to measure phosphorus and carbon on fracture facets combined with EBSD measurements direct from the fracture surface. In total, 700 misorientations were measured from across the reconstructed fracture surface and in 'control' areas away from the fracture. It was found that Sigma 3s were in general more resistant to brittle fracture than were random boundaries, and it was suggested that alloys of this type could be grain boundary engineered to improve fracture resistance by a short anneal in the austenite region to increase the final proportion of Sigma 3s. Sixteen fracture facets yielded combined Auger/EBSD data. The combined Auger/EBSD methodology to acquire joint crystallographic and segregation information from facets was shown to be feasible, although laborious. There were significantly more [110] planes than any other type in the sample population of facets from which combined segregation/crystallography data had been collected. The data suggested that there was on average lower phosphorus segregation on fracture facets that were near [110] than on other intergranular fracture facets.

Frequency of color blindness among Nigerian school children in Lagos.

Plates 1-15 of the Ishihara tests for color blindness were administered to 5,580 boys and 5,405 girls in primary and secondary schools in Lagos. The difference between males and females in the frequency of total color blindness was not significant. The frequency of total color blindness among the children was 0.19%. However, the frequencies of red-green color blindness, which were 3.60% and 0.81% among the males and females, respectively, were significantly different. Deutans occurred at a higher frequency than protans among both male and female red-green color blind individuals, but the differences among males and also females were not significant. In addition, there was no significant difference between the sexes in the occurrence of deutans and protans. Although the frequency of red-green color blindness detected among males in this study is significantly lower than that reported for Lagos in another survey, which gave a frequency similar to that for Caucasians, the frequency obtained in the present study is similar to frequencies reported for other populations of Blacks of African Ancestry. Am. J. Hum. Biol. 10:283-288, 1998. © 1998 Wiley-Liss, Inc.

Genetic load in chromosomes 3 in a population of Drosophila melanogaster in Lagos, Nigeria.

Among 194 chromosomes 3 tested, 48.2% were lethal, 13.4% semilethal, 14.4% subvital, and 29.4% non-lethal. The genetic load in the population is high since only about 30% of the chromosome did not reduce viability, and the frequency of drastic (lethals and semilethals), 56%, is among the highest reported for the chromosome. The frequency of lethals is also high. The rate of allelism is low, only 0.5% among the 28 lethals tested. There were, however, 5 probable cases of pseudoallelism in which some non-allelic lethal chromosomes were either semilethal or subvital in the heterozygous condition.

Mitotic effects of the aqueous leaf extract of Cymbopogon citratus in Allium cepa root tips.

Aqueous extracts of the lemon grass, Cymbopogon citratus, were used to clear the malaria parasite in infected mice, although they died some days later. Allium cepa roots grown in aqueous extracts from 3, 6, 12 and 20 g of chopped leaves for 1, 3, and 6 h, showed some mitotic abnormalities including c-mitotic and mitodepressive effects. The abnormalities were not peculiar to any concentration or duration of extract treatment. The highest frequency of affected cells was 0.75% in the treatment with the 20 g concentration, but the 3 h treatment group had the greatest variety of effects. The mitodepressive effect of the extract increased significantly with concentration and time, and persisted even after 24 h in tap water. The chromosomal effects of the extract occur at a very low frequency but the mitodepressive effects may have implications for man.

Patients with dementia and their caregivers 3 years after diagnosis. A longitudinal study.

OBJECTIVES: To document caregivers' perceptions of the deterioration in functional ability of persons with dementia over time, to identify the most problematic behavior for caregivers at two stages of dementing illness, and to compare the perceived informational needs of caregivers at diagnosis and 3 years later. DESIGN: Single cohort. Surveys were mailed at time 1 and respondents were followed up after 3 years (time 2). SETTING: Midwestern hospital dementia assessment clinic with a family physician director. Continuing care was by community physicians. SUBJECTS: Thirty elderly patients with dementia who were evaluated at the dementia clinic. Data were provided by their caregivers. RESULTS: Patients' scores on the Activities of Daily Living section of the questionnaire declined (bathe self, P = .03; transfer from bed or chair, P = .03; and groom self, P = .06). Significant deterioration in behaviors over time was found in incontinence (P = .04). Fewer patients were depressed at time 2 (P = .02). The patient behaviors found most troublesome at time 1 were worrying about memory loss, losing or hiding things, feeling blue, experiencing restlessness, having difficulty calculating, experiencing a lack of interest, and having false ideas. At time 2, the greatest problems were having a short attention span, failing to recognize persons or things, experiencing a lack of interest, experiencing restlessness, repeating himself or herself, forgetting where he or she is, speaking incoherently, and being incontinent. Questions caregivers most wanted answered at time 1 concerned possible treatment, the future course of illness, and the cause of the symptoms. At time 2, the concerns were the future course of illness, possible treatment, and disease inheritance. There was significantly more interest in family agreement about care (P = .004) and the need for legal guardianship (P = .001) at time 2. CONCLUSIONS: Caregivers' perceptions of the most frequent and troublesome behaviors of patients with dementia were documented at different stages of the disease. The importance caregivers attached to their requests for information reflected changing but continuing needs for reassurance about the patient's diagnosis and treatment and for help with the psychosocial consequences of dementia. Physicians must be aware of caregivers' needs at different stages of the disease process and be equipped to help them appropriately.

Profuse diarrhea after misoprostol use in a patient with a history of Crohn's disease.

OBJECTIVE: To report a case of profuse diarrhea after misoprostol use in a patient with a history of Crohn's disease and to discuss the role of eicosanoids in Crohn's disease. DATA SOURCES: Patient medical records, case reports, review articles identified by MEDLINE, and personal communication with the physician, patient, and manufacturer. DATA EXTRACTION: From interviews, the manufacturer, and pertinent published sources by one author and reviewed by the others. DATA SYNTHESIS: A 55-year-old woman presented to clinic complaining of multiple joint pains. Her medical history was significant for peptic ulcer disease, hypertension, and Crohn's disease in remission since May 1989. Her joint pains were treated with ibuprofen 600 mg po qid and misoprostol 200 micrograms po qid (after meals and at bedtime). Following the administration of three doses of ibuprofen and misoprostol, the patient experienced abdominal cramps, pain, and voluminous, watery diarrhea for two days. Upon discontinuation of the ibuprofen and misoprostol, all of her gastrointestinal symptoms resolved within 12 hours. Rechallenge with ibuprofen alone failed to produce a recurrence of symptoms. Enhanced synthesis of intestinal eicosanoids has been demonstrated in Crohn's disease. Misoprostol, a synthetic analog of one of the eicosanoids, could induce a flare-up of Crohn's disease as suggested in this patient. CONCLUSIONS: Misoprostol should be used with caution in patients with known inflammatory bowel disease.

Management of depression in the elderly.

Primary care physicians have a vital role to play in identifying depression in their elderly patients. Diagnosis may be difficult, because symptoms are atypical and frequently include psychomotor agitation, somatic symptoms, and complaints of memory loss. Patients with medical illnesses, such as cancer, postmyocardial infarction, stroke, Parkinson's disease, and early Alzheimer's disease are particularly vulnerable to depression. Drugs that may cause depressive symptoms are digitalis at toxic levels, beta-blockers, centrally acting antihypertensives, immunosuppressants, and nonsteroidal anti-inflammatory agents. Cyclic antidepressants are the drugs of first choice. Selection depends on the patient's physical health and current medications and the side effect profile of the drug. Side effects are more pronounced in old age because of drug accumulation owing to slowed clearance. Troublesome side effects are anticholinergic effects, orthostatic hypotension, sedation, cardiotoxicity, and weight gain. The most useful antidepressants for geriatric patients are the secondary amines, desipramine and nortriptyline. The second-generation drug trazodone has the advantage of causing the least anticholinergic effects, but it is very sedating. Before treatment, the patient should have an electrocardiogram, liver function tests, tonometry, sitting and standing blood pressures, evaluation of urinary symptoms for outflow obstruction, review of current medications, and estimation of suicide risk. Cyclic antidepressants are contraindicated during recovery from myocardial infarction, in heart disease when there is severe impairment of myocardial performance, in seizure disorders, and in the presence of glaucoma or a large prostate. Drug interactions that may cause trouble can occur with epinephrine, MAO inhibitors, thyroid hormone, cimetidine, and centrally acting antihypertensives. Dosage should start low, increasing usually by 25 mg every 4 to 5 days until a therapeutic level is reached. Failure of a noradrenergic antidepressant after 4 to 5 weeks can be followed by a trial of a serotonergic drug. Drug serum level monitoring is useful for imipramine, desipramine, and nortriptyline. Monoamine oxidase inhibitors are effective in many elderly patients who are resistant to TCAs. Sympathomimetic drugs must be avoided with MAOIs. Elderly patients are at high risk of toxicity and drug interactions with lithium. Electroconvulsive therapy is useful for patients who do not respond to drug treatment, but medical complications, particularly cardiovascular, often occur in patients 75 or older. Many patients relapse after ECT. Psychotherapy together with pharmacotherapy may be the optimal treatment for elderly depressives. Older patients are more likely to become chronically depressed than younger patients. The risk of suicide in depressed elderly males is high, particularly in those with psychosocial problems, and depression rises with age.

Once-daily propranolol for hypertension: a comparison of regular-release, long-acting, and generic formulations.

This randomized, single-blind, crossover study compared three formulations of propranolol, each given once daily for hypertension. After an initial titration phase, subjects randomly received regular-release, long-acting, or a generic propranolol formulation. Each drug was given for 4 weeks and each active treatment was separated by a washout phase to allow blood pressure to return to baseline. Twelve subjects received all three active treatments. Systolic and diastolic blood pressures and pulses were significantly reduced from baseline by all formulations. There was no significant difference among drugs. Examination of diastolic blood pressures suggested some loss of antihypertensive control at the end of the dosing interval. These results indicate that it may be possible to administer propranolol once daily for hypertension and that there is no advantage for using the long-acting form.

Frequencies of attached and free ear lobes in Lagos (Nigeria).

A sample of 1,600 unrelated individuals in Lagos (Nigeria) were examined for attached or free ear lobes. Pedigree data were obtained for 11 families by questionnaire. The corrected proportion of attached among the progeny of free X free was 0.27 compared to an expected value of 0.25. The observed frequencies of the three types of marriages were not significantly different from the expected values derived from the frequencies of the traits in the population. Males and females in the population were equally affected by the traits. Thus, the population frequency of attached is 25.37%, a value within the range for Caucasoids but lower than for Mongoloids.

The nonuse of free health-screening by rural elderly.

We studied the population of noninstitutionalized elderly persons in Iowa County, Iowa, who had not used a well-elderly clinic offering free home or clinic assessments by a nurse. Questionnaires were administered by trained interviewers to a sample of the nonuser population, 60 years of age and over (n = 360). Fifty-five percent did not know that there was a well-elderly clinic in the county in spite of widespread advertising. Nonusers who had heard of the clinic were more highly educated and had more transportation problems than nonusers who were aware of the clinic. Sixty percent of those who saw no point in going to a doctor if they were feeling well were unaware of the clinic. Nonusers tended to be older, living on farms, mobile, long-time residents, and 54 percent had less than a high school education. The cost of health care was not a problem. The major reason given for not using the clinic was that the person was "under a doctor's care." Those who had no regular doctor did not plan to use the clinic because they felt healthy.

The elderly hypertensive: a neglected patient?

A cohort of 1,002 elderly hypertensive patients who received care at six family practice residency program clinics in Iowa was followed for nearly four years in a historical prospective design study. Demographic and clinical data were abstracted and the end points of the study were the occurrence of a cerebrovascular accident (n = 37), myocardial infarction (n = 27), or death (n = 102). Survival regression analysis showed that the risk of cerebrovascular accident is greater than any other major morbid event and that risk is proportional to increasing levels of both systolic and diastolic blood pressure. The findings are in agreement with published studies of hypertension and its treatment in other age groups.