Conceptual design of the time-of-flight backscattering spectrometer, MIRACLES, at the European Spallation Source.

In this work, we present the conceptual design of the backscattering time-of-flight spectrometer MIRACLES approved for construction at the long-pulse European Spallation Source (ESS). MIRACLES's unparalleled combination of variable resolution, high flux, extended energy, and momentum transfer (0.2-6 Å(-1)) ranges will open new avenues for neutron backscattering spectroscopy. Its remarkable flexibility can be attributed to 3 key elements: the long-pulse time structure and low repetition rate of the ESS neutron source, the chopper cascade that tailors the moderator pulse in the primary part of the spectrometer, and the bent Si(111) analyzer crystals arranged in a near-backscattering geometry in the secondary part of the spectrometer. Analytical calculations combined with instrument Monte-Carlo simulations show that the instrument will provide a variable elastic energy resolution, δ(h ω), between 2 and 32 µeV, when using a wavelength of λ ≈ 6.267 Å (Si(111)-reflection), with an energy transfer range, h ω, centered at the elastic line from -600 to +600 µeV. In addition, when selecting λ ≈ 2.08 Å (i.e., the Si(333)-reflection), δ(h ω) can be relaxed to 300 µeV and h ω from about 10 meV in energy gain to ca -40 meV in energy loss. Finally, the dynamic wavelength range of MIRACLES, approximately 1.8 Å, can be shifted within the interval of 2-20 Å to allow the measurement of low-energy inelastic excitations.

Evolution of chemical species during electrodeposition of uranium for alpha spectrometry by the Hallstadius method.

The morphology and composition of uranium alpha sources with co-deposited platinum have been investigated by scanning electron microscopy (SEM) with energy dispersive X-ray fluorescence analysis (EDX), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) studies. Combined SEM and EDX measurements reveal the effect of porous platinum on the morphology of the sources which in turn affects their alpha-spectral resolution. The XPS analysis suggests that the presence of platinum initially increases the concentration of hydroxyl species in the deposits, which then act as centres for subsequent preferential uranium precipitation. XPS and XAFS analysis also provide for first time an indication of oxidation states of uranium present in the sources prepared by the Hallstadius method. These results are in line with Hansen's theory of electrodeposition of actinides.

Role of digital artery adrenoceptors in Raynaud's disease.

Raynaud's disease is characterized by excessive cutaneous vasoconstriction in response to ambient cold. A functional disturbance in the local regulation of digital vasomotion has been proposed. The purpose of this study was to determine whether there is an alteration in the postjunctional adrenergic receptors in the digital circulation of patients with Raynaud's disease. Furthermore, we sought to determine whether this abnormality was responsible for the excessive cold-induced vasoconstriction in these patients. Finger blood flow was measured by strain-gauge venous occlusion plethysmography in 10 patients with Raynaud's disease and in 10 normal volunteers in a 22 degrees C room. Measurements of finger blood flow and mean systemic arterial pressure were made during intra-arterial infusions of the alpha 1-adrenergic antagonist, prazosin, or the alpha 2-adrenergic antagonist, yohimbine, at room temperature and during local cooling of the hand. Basal finger blood flow in normal subjects was significantly greater than that of patients (8.6 +/- 2.7 vs 1.7 +/- 0.5 ml/100 ml per min; normal vs Raynaud's subjects; p < 0.05). In normal subjects, either prazosin or yohimbine induced dose-dependent increases in finger blood flow. The maximal increase in finger blood flow induced by prazosin was significantly greater than that in response to yohimbine (29.2 +/- 10.1 vs 2.8 +/- 2.1 ml/100 ml per min; prazosin vs yohimbine; p < 0.05). By contrast, in the Raynaud's patients, prazosin or yohimbine induced maximal increases in finger blood flow that were not significant (7.1 +/- 1.8 vs 5.0 +/- 2.2 ml/100 ml per min; prazosin vs yohimbine; p = NS). The response to prazosin in Raynaud's patients was significantly less than that of the normal volunteers (p < 0.05). In normal subjects, during intra-arterial infusion of vehicle alone, cooling induced a 52.6 +/- 5.8% reduction in finger blood flow. This cold-induced vasoconstriction was blunted, but not qualitatively altered, by either adrenergic antagonist. In the Raynaud's patients, during the intra-arterial infusion of the vehicle, cooling induced a 68.2 +/- 7.8% reduction in finger blood flow. Infusion of either adrenergic antagonist blunted, but did not qualitatively alter, the response to cold. Finger blood flow is less in patients with Raynaud's disease than in normal subjects when studied in a 22 degrees C room. In normal subjects, postjunctional alpha 1-adrenergic receptors appear to predominate in the control of digital vasoconstriction. Postjunctional alpha 1- and alpha 2-adrenoceptors play an equal role in adrenergic regulation of finger blood flow in patients with Raynaud's disease. In both normal and Raynaud's subjects, selective antagonism of alpha 1- or alpha 2-adrenergic receptors does not abolish local cold-induced vasoconstriction. Therefore, it is likely that a nonadrenergic mechanism contributes to local cold-induced vasoconstriction.

Association between Raynaud's phenomenon and migraine in a random population of hospital employees.

OBJECTIVE: To determine the relationship between migraine and Raynaud's phenomenon. METHODS: A detailed headache questionnaire was completed by 41 subjects with Raynaud's phenomenon identified in a random survey of hospital employees and by a group matched for age and sex without Raynaud's phenomenon. RESULTS: The prevalence of migraine was increased significantly in the group with Raynaud's phenomenon compared with the control group (24/41, 58.5% vs 10/41, 24.4%; p = 0.002). This result agrees with findings in hospital-based studies of patients with Raynaud's phenomenon. CONCLUSION: The prevalence of migraine is significantly increased in subjects with Raynaud's phenomenon, suggesting that these conditions may share a common pathogenetic defect or mechanism.

Blue toe syndrome. Causes and management.

The sudden development of cyanotic lesions on the feet may be a result of atheroembolic disease or a number of medical conditions. A careful history and physical examination, basic laboratory tests, and noninvasive vascular assessment usually distinguish between medical and surgical causes and direct the choice of further investigations. Specific therapy is often available for medical conditions causing this syndrome. The management of atheroembolic disease is more controversial. In particular, further research is necessary to determine which patients need surgical intervention and which patients can be managed safely by medical therapy.

Color chart assisted diagnosis of Raynaud's phenomenon in an unselected hospital employee population.

The prevalence of Raynaud's phenomenon (RP) in 750 subjects was assessed by questionnaire, clinical interview, and use of a chart of color photographs taken of hands during attacks of RP. Eighty-three of 600 women (13.8%) and 7 of 150 men (4.7%) reported cold induced digital color changes on the questionnaire, 76 women (12.7%) and 6 men (4%) were diagnosed as having RP at an independent clinical interview, and 3 women could not be assessed using the color chart because of defective color perception. Fifty-four of the remaining 597 women (9%) and 6 of 150 men (4%) were diagnosed as having RP when a positive response to both chart and questionnaire was required. The color chart should be useful in lessening the frequency of false-positive responses and in standardizing the diagnosis for epidemiological surveys.

Renal revascularization to preserve and restore renal function.

A total of 97 patients underwent 107 renal revascularization procedures for restoration and preservation of renal function. Of the 4 groups of high risk surgical patients that emerged an overall successful outcome was achieved in 83%, with a 6% mortality rate and an 11% morbidity rate. Renal revascularization for restoration and preservation of renal function can be performed safely with good results. The preoperative serum creatinine level was not predictive of the surgical outcome. Alternative bypass procedures are preferred.

Increased prevalence of migraine and chest pain in patients with primary Raynaud disease.

OBJECTIVE: To investigate the prevalence of headaches and recurrent chest pain in patients with primary Raynaud disease. DESIGN: Postal survey. SETTING: Raynaud disease clinic at the Lahey Clinic Medical Center, a tertiary care hospital. PARTICIPANTS: A consecutive series of 120 patients with primary Raynaud disease who had been observed for at least 2 years, 97 of whom received and 93 of whom completed the questionnaire, and a control group of 93 age- and sex-matched hospital employees without Raynaud phenomenon. RESULTS: Migraine was diagnosed in 57 (61%) patients with primary Raynaud disease and in 21 (23%) of the control group (odds ratio, 5.4; 95% CI, 2.8 to 10.3). Migraine with aura and migraine without aura were more common in patients with Raynaud disease than in the control subjects (27% compared with 5%; P less than 0.001 and 34% compared with 17%; P = 0.008, respectively). Nonmigrainous headaches were more common in the control group (51% compared with 25%; P = 0.003). Chest pains were reported by 44 (47%) of the patients with Raynaud disease and by 15 (16%) of the control group (odds ratio, 4.4; CI, 2.4 to 9.3). Chest pains were more frequently reported by patients with Raynaud disease who had migraine (34 of 57, 60%) than by patients without migraine (10 of 36, 28%; P = 0.003). CONCLUSIONS: An increased prevalence of migraine was found in patients with primary Raynaud disease. Chest pain, often diagnosed as musculoskeletal or nonspecific, was common in patients with primary Raynaud phenomenon, especially in patients who had coexisting migraine.

Osler's maneuver in an outpatient clinic setting.

Osler's maneuver was performed on 912 consecutive outpatients aged 60 years of older in a 2-month period by 12 physicians. The incidence of an Osler-positive finding was 7.1% (65/912). The number of positive findings increased with age, ranging from 3.4% in the 60- to 70-year age group to 43.8% in the 86- to 90-year age group. A history of hypertension was present in 58.4% of patients with Osler-positive findings and in 59.6% of patients with Osler-negative findings. In a group of 48 previously screened patients who were independently examined, concordance was poor when the kappa test of reliability was used. Positive Osler findings were common in patients older than 70 years, in patients who smoked, and in patients with a high systolic blood pressure. These correlations may be related to a decrease in blood vessel compressibility, which may cause pseudo-hypertension. However, the findings on Osler's maneuver, are poorly reproducible, making the procedure an inadequate test.

Abdominal aortic aneurysms.

Modern surgical techniques permit repair of abdominal aortic aneurysms and prevent eventual rupture, with a mortality rate of only a few percent. Coronary heart disease is the chief cause of death, depriving the patient of an assumed improved life expectancy after successful operation for aneurysm. Therefore, aggressive preoperative cardiac evaluation, including coronary arteriography and perhaps more protective myocardial revascularization procedures, is indicated.

Temporal arteritis. General review with emphasis on atypical manifestations and cardiovascular complications.

Temporal arteritis is a common disease of the elderly. Although overall mortality does not differ between patients with temporal arteritis and the general population of similar age, temporal arteritis does cause major morbidity and death. Early diagnosis and treatment with corticosteroids can prevent these complications.

Low-dose heparin. A cause of hematoma of rectus abdominis.

Although hematomas of the rectus abdominis muscle are commonly reported complications of systemic anticoagulation treatment, they are a rare complication of prophylactic administration of low-dose heparin. The occurrence of a massive hematoma of the rectus sheath is reported in a woman with chronic obstructive pulmonary disease and acute respiratory failure who was receiving low doses of heparin for the prevention of deep venous thrombosis. Three other cases of hematoma of the rectus sheath resulting from prophylactic use of heparin are reviewed. The development of hematoma in these patients may have resulted from intramuscular abdominal injection of heparin and from strain of the rectus abdominis muscle caused by coughing. When prophylactic administration of heparin is necessary in patients with a tendency to paroxysmal cough, subcutaneous injections of heparin in the thigh may be preferable to subcutaneous injections in the abdomen.

Preoperative and surgical management of pheochromocytoma.

The clinical awareness of the various presentations of pheochromocytoma, along with newer monitoring and anesthetic techniques, has enabled early diagnosis and less fluctuation of blood pressure during operation. The use of meticulous surgical technique through the various incisions outlined in this article has made the excision of pheochromocytoma an expeditious operation and the accompanying hypertension surgically curable. Thus, pheochromocytoma is less likely to be a fatal lesion.

Physiology of the adrenal medulla.

As can be appreciated from this discussion, catecholamines derived from the adrenal medulla have far-reaching effects on human physiology, ranging from direct effects on individual cells to participation in complex behavioral responses.

Changing concepts in surgical management of renovascular hypertension.

As newer surgical techniques and concepts have emerged, including revascularization of the totally occluded renal artery and alternatives to aortorenal bypass (hepatic, splenic, or iliac artery to renal artery grafts), our patient population has changed. Patients with diffuse atherosclerotic disease, bilateral renal artery stenosis, totally occluded renal arteries, and azotemia are being referred for renal revascularization, thereby changing the indications for operation and the results that can be anticipated. Although our results in patients operated on solely for uncontrollable hypertension or renal failure have been successful, much work needs to be done to improve the results obtained when patients have a combination of uncontrollable hypertension and renal failure.