New avenues for residual stress analysis in ultrathin atomic layer deposited free-standing membranes through release of micro-cantilevers.

The fabrication of thinnest, yet undeformed membrane structures with nanometer resolution is a prerequisite for a variety of Microelectromechanical systems (MEMS). However, functionally relevant thin films are susceptible to growth-generated stress. To tune the performance and reach large aspect ratios, knowledge of the intrinsic material properties is indispensable. Here, we present a new method for stress evaluation through releasing defined micro-cantilever segments by focused ion beam (FIB) milling from a predefined free-standing membrane structure. Thereby, the cantilever segment is allowed to equilibrate to a stress-released state through measurable strain in the form of a resulting radius of curvature. This radius can be back-calculated to the residual stress state. The method was tested on a 20 nm and 50 nm thick tunnel-like ALD Image 1 membrane structure, revealing a significant amount of residual stress with 866 MPa and 6104 MPa, respectively. Complementary finite element analysis to estimate the stress distribution in the structure showed a 97% and 90% agreement in out-of-plane deflection for the 20 nm and 50 nm membranes, respectively. This work reveals the possibilities of releasing entire membrane segments from thin film membranes with a significant amount of residual stress and to use the resulting bending behavior for evaluating stress and strain by measuring their deformation.

Carotid endarterectomy: time-trends and results during a 20-year period.

AIM: The aim of this study was to evaluate the results following surgery for carotid artery stenosis in a single institution during a 20-year period. METHODS: In a retrospective study, 556 operations were performed in 496 patients during the period 1983-2002. Comorbidities, mortality, stroke and other surgical and general complications were recorded. Follow-up was performed and data retrieved from medical records, questionnaires, and visits to local hospitals. Data on late mortality were retrieved from the Norwegian Registrar's Office of birth and deaths. RESULTS: The mean age was 66.9 years (range 43-84 years), and 60% were men; 84% had symptomatic carotid artery stenosis. General anesthesia was applied in 95.5%. A shunt was used in 61.3%, and patch angioplasty in 95.1%. Autologous vein patch was used in almost all cases and there were no cases of patch rupture. Postoperative myocardial infarction occurred in 16 (2.9%) of the patients, and 5 were fatal. All types of stroke within 30 days of surgery occurred in 23 (4.1%) including 1 fatal stroke, and 7 patients died of other causes. The total stroke/mortality rate was 5.4%. Patients with previous coronary artery bypass had a favorable outcome regarding long-time survival. In contrast, increasing age, diabetes, renal failure and intermittent claudication predicted reduced long-term survival. No operations were performed for recurrent stenosis. CONCLUSIONS: We have used fairly the same policy regarding operative technique during the 20-year period and the results are in agreement with those presented in large international trials. The long-term results were favorable, and improved over time, probably due to better preoperative evaluation of the patients, better timing of surgery and treatment of comorbidities.

Headache and transient focal neurological symptoms during pregnancy, a prospective cohort.

OBJECTIVE: The main purpose of the present prospective study was to evaluate the course of migraine and non-migrainous headache during pregnancy and to estimate the occurrence of self-reported transient focal neurological symptoms. MATERIAL AND METHODS: In total 1631 (77%) pregnant women completed the study and were followed-up during pregnancy. The first questionnaire (Q1) was sent together with the appointment letter and delivered at the time of ultrasound screening. The second questionnaire (Q2), to be filled in during pregnancy, was delivered at the time of birth. Q1 and Q2 covered questions about headache, transient neurological symptoms, and other background and demographic data. Subjects reporting transient sensory, motor or visual disturbances were also interviewed by phone in order to achieve a more precise description of the symptoms. RESULTS: A total of 58% subjects with migraine reported not having migraine or no headache at all during pregnancy. Among individuals with non-migrainous headache 25% reported not having any headaches, while 1.9% of the subjects without headache experienced headache attacks during pregnancy that fulfilled the criteria for migraine. Individuals without headache or with non-migrainous headache reported significantly less sensory, motor and visual disturbances during pregnancy compared with migraine subjects. More than 60% of those with possible aura phenomenon were migraine patients, while symptoms of peripheral or non-neurological origin were more common among headache free or those with non-migrainous headache. CONCLUSION: Transient neurological symptoms were less common among individuals without or with non-migrainous headache compared with migraine. This may indicate that there is an increased susceptibility of unknown cause for these symptoms among migraine patients during pregnancy.

SUNCT syndrome: estimation of cerebral blood flow velocity with transcranial Doppler ultrasonography.

Four patients with SUNCT syndrome (Short-lasting, Unilateral, Neuralgiform headache attacks with Conjunctival injection and Tearing) were investigated with Doppler ultrasonography. Blood flow velocity (V) was measured in all intracranial arteries during both normocapnia and voluntary hyperventilation in 4 patients outside attacks (2 during remission; 2 during bout, but outside attacks) and in 8 healthy individuals. Vasomotor reactivity (VMR) was calculated on the basis of the formula of percentage change in V divided by the reduction in end-tidal PCO2 (PETCO2). Under the basal condition, the patients had a slightly, but non-significantly higher V in the middle cerebral artery (MCA) (P > 0.1) and lower V in the basilar artery (P > 0.05) than controls. During hyperventilation, a significant reduction in V was observed in the anterior and posterior cerebral arteries, at a level 1.5-2 SD above that in controls (P < 0.05), but a non-significant difference in VMR in comparison with controls. VMCA was continuously insonated during spontaneous (n = 8) and precipitated (n = 4) attacks in one particular patient on different days. Prior to attack, VMCA was significantly lower on the symptomatic side than on the non-symptomatic side (P < 0.014). VMCA decreased significantly during spontaneous attacks on both sides (P < 0.01) in comparison with the pre-attack stage, and returned to baseline before the cessation of attack. Similar findings were made during precipitated attacks. PETCO2, was rather constant throughout the entire attack study. Our data suggest that abnormal cerebral circulation may be part of the SUNCT syndrome. The vascular changes may have underlying mechanisms differing from those of the pain.

Cluster headache: transcranial Doppler assessment of dynamic cerebral circulatory changes during hypocapnia and attack.

Transcranial Doppler ultrasound (TCD) investigations have been carried out in cluster headache patients (8 during remission and 6 during bout) and 14 healthy subjects, to assess cerebral vasomotor reactivity (VMR) to hypocapnia induced by voluntary hyperventilation. VMR was expressed as the relative change in blood flow velocity (V) (%) as a function of the reduction in end-tidal PCO2 (PETCO2) (kPa), i.e. V/P ETCO2. TCD with simultaneous PETCO2 monitoring, was also performed in 5 patients during spontaneous attacks. Prior to hyperventilation, there was bilaterally lower anterior cerebral artery velocity (VACA) during the bout than during remission (P < 0.05 on the symptomatic side), and also lower than in the controls. During remission, VACA was higher on the symptomatic side than on the other side (P < 0.05). ACA also showed a lower VMR during the bout than during remission, and it was also lower than in controls (bout vs. remission on the non-symptomatic side, P < 0.01; on the symptomatic side, P > 0.1). Approximately 30 minutes after the onset of attack, PETCO2 started to decrease gradually from 4.65 to 4.10 kPa in one patient with severe attack. The VACA decreased markedly and bilaterally already at an early stage of the attack, i.e. prior to the hyperventilation. Middle cerebral artery velocity tended to decrease 30 minutes after the onset of attack on the symptomatic side, and 50 minutes after onset on the non-symptomatic side. It is concluded that the vascular changes observed most likely are secondary phenomena during the cluster headache attack.

[Glossopharyngeal neuralgia. Not just pain]. / Glossopharyngeusneuralgi. Ikke smerter alene.

Glossopharyngeal neuralgia is a rare disease characterized by severe paroxysmal attacks of pain in the distribution of the 9th cranial nerve. The most important differential diagnosis is trigeminal neuralgia. Carbamazepin is the current drug of choice in therapy, but modern neurosurgical treatment will probably become more common in the future. Autonomic disturbances may occur during pain attacks in some patients. We describe a patient suffering from glossopharyngeal neuralgia with transitory unconsciousness due to cardiac asystole and arterial hypotension accompanying the attack of pain.

[Elevated intracranial pressure following brain infarction--a retrospective study]. / Forhøyet intrakranialt trykk ved hjerneinfarkt--en retrospektiv undersøkelse.

Brain infarction is a frequent cause of emergency admission to hospital. We have made a retrospective study in order to describe patients who develop fatally elevated intracranial pressure. From 1991 to 1993, seven patients (3.3%) died within the first 96 hours after the symptoms appeared. All these patients died from elevated intracranial pressure caused by oedema in and around an infarction in the territory of the middle cerebral artery. These patients were significantly younger than the general population of patients with infarction (p < 0.01), and also younger than the patients who died from other causes during the observation period (p < 0.01). We think that these cases underline the importance of establishing effective acute treatment for ischemic cerebrovascular diseases, since this is probably the only effective way to protect against formation of oedema.

The urinary excretion of deoxypyridinium cross-links is higher in diabetic than in nondiabetic adolescents.

We have measured the urinary excretion of deoxypyridinium (D-Pyr) crosslinks, a sensitive and specific marker of bone resorption, in morning urine in 102 healthy, nonhospitalized, Caucasian subjects (8-18 years) and in 18 diabetic subjects (12-17 years). The free D-Pyr crosslinks were measured using the Pyrilinks D-Assay. In the diabetic subjects, plasma glucose was regulated throughout the night by a constant infusion of insulin and a variable infusion of 24% glucose. In the nondiabetic subjects, the excretion of D-Pyr increased until 12-14 years of age, and thereafter decreased, and the excretion of D-Pyr/hour was correlated with the height Z-score. The excretion of D-Pyr/hour and the D-Pyr/creatinine ratio was higher in the diabetic adolescents than in the nondiabetic adolescents. In subjects over the age of 12, the D-pyr/creatinine ratio was higher in males than in females. In conclusion, in healthy children and adolescents, the excretion of D-Pyr peaks at 12-14 years of age. The D-Pyr excretion is higher in diabetic than in nondiabetic adolescents, suggesting increased bone resorption in diabetic adolescents.

[Mononucleosis and neurological manifestations]. / Mononukleose og neurologiske manifestasjoner.

Infectious mononucleosis is a relatively common disease. In this paper, three patients with neurological symptoms related to infectious mononucleosis are described. Patient no. 1 had myelitis, one of the most frequent neurological complications. Patient no. 2 had cerebellar symptoms, with ataxia and disturbance of gait. In this case magnetic resonance revealed vermis atrophy, a finding which, to the best of our knowledge, has not been reported before. Patient no. 3 had bilateral optic neuritis. Repeated serologic tests may be necessary to confirm the diagnosis. Infectious mononucleosis should be considered in younger patients with neurological symptoms of uncertain origin.

Associated disorders in myasthenia gravis: autoimmune diseases and their relation to thymectomy.

The prevalence of myasthenia gravis (MG) in the counties of Hordaland and Sogn & Fjordane on January 1, 1984 was 9.6 per 100,000 inhabitants. Other autoimmune diseases were found in 11 out of 48 MG patients. The occurrence of autoimmune thyroiditis (5 patients, 10.4%) and systemic lupus erythematosus (4 patients, 8.3%) in the MG patients was clearly higher than that reported in the general population. Rheumatoid arthritis was found in 2 patients (4.2%). The autoimmune diseases were mainly recorded among the nonthymectomized MG patients. In addition to those with definite diseases of autoimmune nature, 3 other MG patients had thyroid antibodies and 1 had antinuclear factor without clinical evidence of autoimmune disease. Seven MG patients (14.6%) had unspecific arthralgia during active periods of MG. Two MG patients had ankylosing spondylitis.

Recovery from global amnesia during plasma exchange in myasthenia gravis: report of a case.

A 47-year old thymectomized woman with myasthenia gravis, receiving prednisone therapy, developed amnesia for recent events during a benign acute febrile illness. Plasma exchange was performed 9 months later, and was followed by a dramatic improvement of the mnemonic dysfunction.

[Intravenous thrombolytic treatment of acute basilar artery occlusion]. / Intravenøs trombolytisk behandling ved akutt okklusjon i a. basilaris.

BACKGROUND: Acute stroke with basilar artery occlusion is a serious condition with high mortality and severe disability. MATERIAL AND METHODS: We describe three patients with acute artery basilar occlusion treated with thrombolytic agent given intravenously. RESULTS: One patient demonstrated early and considerable clinical improvement parallel to thrombolytic therapy started two and a half hour after ictus, but suffered a new occlusion and died in a "locked-in syndrome". One patient demonstrated moderate clinical improvement after less than six hours and survived with disability. One patient demonstrated no clinical improvement with thrombolytic therapy started six hours after ictus and later died of an injured brainstem. No patients had serious bleeding. INTERPRETATION: Intravenous, systemic thrombolytic treatment may have a beneficial effect in acute basilar occlusion.

[Elevated intracranial pressure following brain infarction--therapeutical possibilities]. / Forhøyet intrakranialt trykk ved hjerneinfarkt--terapeutiske muligheter.

Elevated intracranial pressure is a serious complication in the early phase after brain infarction. The most frequent cause of the elevated pressure is oedema following an infarction in the territory of the middle cerebral artery. Non-surgical treatment is inadequate in many of the patients. Although anecdotal, several reports concerning neurosurgical treatment seem to be optimistic. We think that such treatment could be given to selected young patients with large hemispheric infarctions and cerebral oedema.

[Neuralgic amyotrophy or an isolated lesion of the anterior interosseal nerve?]. / Neuralgisk amyotrofi eller en isolert lesjon av nervus interosseus anterior?

In this article we describe five patients with acute or subacute weakness of flexor pollicis longus and flexor digitorum profundus. A possible diagnosis of an isolated lesion (entrapment) of the anterior interosseus nerve was considered. However, clinical and neurophysiological findings suggested a diagnosis of neuralgic amyotrophy. Three patients experienced acute shoulder pain at the onset. Sensory loss at the base of the thumb was observed in two patients, and two patients were affected bilaterally. All patients had EMG signs of involvement outside the anterior interosseus nerve innervation area. Low amplitude sensory action potentials were observed in three patients. One patient was operated upon and entrapment was not observed during surgery. Reinnervation was not seen after five months, but was noted in three patients who were investigated 13, 13.5, and 30.5 months after the onset. Thus, the prognosis in this unusual form of neuralgic amyotrophy seems to be rather good, and the length of time before reinnervation supports the theory that the site of the lesion must be located proximally, e.g. in the brachial plexus.

The value of dorsal column stimulation in multiple sclerosis.

Ten patients with definite and one with probable MS, all markedly inflicted, but with a varying degree of motor and bladder dysfunction were subjected to spinal cord stimulation in a controlled study. None of the patients exhibited appreciable fluctuation in symptoms in the pre-study period. Bladder symptoms were most markedly influenced by electrical stimulation. The reduction in hesitancy and urgency was of great importance to the patients. In 9 of 10 patients reduction in voiding frequency took place, the all over reduction being 8%. Maximum extension torque increased by 9% and flexion torque by 29% during the stimulation when compared to the first placebo period. In selected MS patients, i.e. patients with bladder dysfunction and with a certain muscular reserve, electrical spinal cord stimulation may have an indication.