House walls as passive solar collectors: An assessment

The gross solar energy falling on a typical house during the heating season is greater than the space heating requirement. Conventional solar collectors produce hot water, which is then used to meet the domestic hot water and space heating requirements of the house. Such collectors, however, are expensive, and it is only possible to use them to collect a small proportion of the available solar energy. This paper looks at an alternative approach of using the entire wall surface as a passive solar collector, by using an external layer of translucent insulation. Measurements and calculations are reported which show that a wall with a double-glazed outer layer would be expected to show a zero net heat loss over the heating season. This is not considered to be sufficient advantage to overcome the cost and other problems associated with the system.     

Study of methods of inactivating a concentrated, purified cultured antirabies vaccine]

Two methods of inactivation, with ultraviolet (UV) and gamma (gamma) rays, of the concentrated purified tissue culture rabies vaccine from the Vnukovo-32 strain were studied. Under the optimal conditions of treatment of 100-fold concentrated purified virus-containing suspension, a completely inactivated vaccine with high immunogenicity indices (4.1 to 78) was obtained. Both the inactivation methods were found to be of equal value.     

Identification of the aberrant hepatic artery with axial spiral CT

PURPOSE: To determine whether axial spiral computed tomography (CT) allows detection of the replaced hepatic artery as part of preoperative planning for pancreatic tumor resection. MATERIALS AND METHODS: Axial spiral CT scans (8-mm section thickness, 4-mm overlapping reconstructions) were obtained in 50 patients with periampullary tumor and were examined by three radiologists. Readers' interpretations were compared with angiographic results. RESULTS: Eight patients had an aberrant hepatic artery. Two of the three readers detected or suspected all of these abnormalities (100% sensitivity), and one reader identified seven of eight aberrant arteries (88% sensitivity). However, readers requested angiographic confirmation in 14 of 24 tests. Sensitivity, specificity, and accuracy were 96%, 87%, and 88%, respectively, for all readers. CONCLUSION: Axial spiral CT may simplify preoperative evaluation of periampullary tumors. However, angiographic support was necessary in most cases in this study. Improvements in CT techniques may eventually allow spiral CT to replace angiography in the examination of these patients.     

On the measurement of human strength

Generation of muscle strength is a complex procedure of myofilament activation, nervous feedforward and feedback control, and use of mechanical leverages within the human body. Since strength measurement directly at the muscle is (currently) not feasible, it is usually done at the outside of the body, at the interface with some kind of a dynamometer. This poses various challenges because of difficult mechanical and physiological modelling of the conditions, and because of difficulties in experimental control. To better understand and measure human motor performance, a model of muscle functions and control is discussed, and means for computer-aided position and motion observation are proposed. Experimental variables are classified, and a taxonomy for static (isometric) and several dynamic measurement techniques is described.     

Laparoscopic ultrasonography as compared with static or dynamic cholangiography at laparoscopic cholecystectomy. A prospective multicenter trial

We compared laparoscopic ultrasonography (LICU) with static (S) or dynamic (D) cholangiography (IOC) for assessment of duct anatomy an calculi in 209 patients. LICU visualized ducts in 88% compared with 93% for IOC (P = 0.046). Nineteen patients (9%) had stones: 17 were found by LICU (89%) and 10 (53%) by IOC (P = 0.032). Time to perform LICU (7 +/- 3 min) was less than IOC (13 +/- 6 min) (P < 0.0001). Time to perform SIOC (12 +/- 5 min) and DIOC (14 +/- 6 min) did not differ (P = 0.48), nor did these tests differ in accuracy. LICU provided useful anatomical information but IOC better defined anatomic anomalies. LICU required less time but was less reliable at defining anatomy and complete duct visualization. LICU was more sensitive for stones. SIOC and DIOC did not differ objectively. LICU and IOC are complementary.     

Endotoxin differentially impairs receptor-mediated relaxation in rat isolated pulmonary and thoracic aortic vessels

PURPOSE: The purpose of this study was to determine the effect of endotoxin on vasorelaxation in the pulmonary and systemic circulations in response to the following agonists that require generation of cyclic adenosine monophosphate: (1) beta-adrenergic receptor stimulation with isoproterenol; (2) H2 receptor stimulation with dimaprit; and (3) adenylate cyclase stimulation with forskolin. METHODS: Male Sprague-Dawley rats weighing 250 to 350 g were injected with endotoxin (20 mg/kg intraperitoneal) or saline. Six hours later, the cumulative dose response to beta-adrenergic receptor stimulation (isoproterenol), H2 receptor stimulation (dimaprit), and adenylate cyclase stimulation (forskolin) was determined in isolated rat pulmonary artery and thoracic aortic rings preconstricted with phenylephrine. RESULTS: Endotoxin caused significant impairment of relaxation to isoproterenol in the pulmonary artery, but the response in the aorta was not different from the control response. In the pulmonary circulation, endotoxin converted the response to dimaprit from vasorelaxation to vasoconstriction. On the other hand, dimaprit resulted in vasorelaxation in the thoracic aorta after endotoxin; however, the response was impaired compared with the control response. Endotoxin did not affect the dose response to forskolin in either the pulmonary artery or the thoracic aorta. CONCLUSION: From these data, we conclude that endotoxin causes regional specific changes in vascular reactivity. These changes in vascular reactivity result in preserved vasorelaxation in the systemic circulation and impairment of vasorelaxation in the pulmonary circulation in response to endotoxin.     

Appearance of oxidized cellulose (Surgicel) on postoperative CT scans: similarity to postoperative abscess

OBJECTIVE: Oxidized regenerated cellulose (Surgicel), a sterile knitted fabric that causes thrombus formation because of its physical properties, is frequently used for intraoperative hemostasis. Unlike traditional surgical sponges, it is bioabsorbable and can be left in the surgical bed. On CT scans, the appearance of the retained oxidized cellulose can mimic that of an abscess. The purpose of this study was to describe the appearance of oxidized regenerated cellulose on postoperative CT scans so that an erroneous diagnosis of an abscess can be avoided. MATERIALS AND METHODS: We reviewed the CT examinations of five postoperative patients in whom oxidized regenerated cellulose had been used for surgical hemostasis. Operative reports and surgeons confirmed the use of oxidized cellulose. Four CT scans were abdominal examinations, and one was a head examination. RESULTS: In four cases, CT scans showed focal, linear collections of gas within masses with mixed attenuation in or near the operative site. No air-fluid levels were present. In three patients, cultures of specimens obtained by aspiration were negative for pyogenic organisms. CONCLUSION: Retained oxidized cellulose can mimic an abscess on CT scans. Focal collections of air centrally located within a mass should alert the radiologist that oxidized cellulose may have been placed in the operative site, and an appropriate history should be sought.     

Morvan's fibrillary chorea: a paraneoplastic manifestation of thymoma

Morvan's fibrillary chorea is a rare disease characterised by symptoms which include neuromyotonia, cramping, weakness, pruritus, hyperhidrosis, insomnia, and delirium. The first case of Morvan's fibrillary chorea to be associated with clinical manifestations of myasthenia gravis with thymoma, psoriasis, and atopic dermatitis is reported. Muscle histopathology disclosed chronic denervation and myopathic changes and in vitro electrophysiology demonstrated both presynaptic and postsynaptic defects in neuromuscular transmission. Serum antibodies to acetylcholine receptors, titin, N-type calcium channels, and voltage gated potassium channels were detected. Plasmapheresis, thymectomy, and long term immunosuppression induced a dramatic resolution of symptoms. The association of thymoma with other autoimmune disorders and autoantibodies, and prolonged and sustained remission with chronic immunosuppression, place Morvan's fibrillary chorea on the range of neurological diseases arising as a paraneoplastic complication of cortical thymomas.     

Child feeding and care behaviors are associated with xerophthalmia in rural Nepalese households

OBJECTIVE: To compare the blood-pressure-lowering effects of an angiotensin converting enzyme inhibitor, perindopril, with those of an angiotensin II type 1 receptor antagonist, L-158,809, for adult spontaneously hypertensive rats. DESIGN: A cross-over design was used, to treat adult spontaneously hypertensive rats with one drug for 10 weeks, and then with the other for 5 weeks. METHODS: Adult, male spontaneously hypertensive rats (aged 15 weeks) were treated daily by gavage for 10 weeks with perindopril (P group) or L-158,809 (L group), then treatment was crossed over so that rats in the P group were treated with L-158,809 (P/L group) and rats in the L group were treated with perindopril (L/P group) for 5 weeks. Blood pressure was measured weekly. Plasma angiotensin converting enzyme activity, renal angiotensin receptor density, and arterial structure and functioning were measured after the single and crossover treatment periods. RESULTS: Treatment lowered the blood pressure from 206 +/- 2 mmHg in rats in the control group, to 126 +/- 2 in rats in the P group and 150 +/- 2 in rats in the L group. After the cross-over period, blood pressure decreased further from 150 +/- 2 to 129 +/- 3 mmHg in rats in the L/P group, whereas blood pressure of spontaneously hypertensive rats in the P/L group increased from 126 +/- 2 to 148 +/- 2 mmHg. Perindopril treatment almost abolished plasma angiotensin converting enzyme activity, whereas L-158,809 treatment had no effect. Renal angiotensin II receptor density was decreased versus baseline in rats in the P and L groups. The affinity of binding was decreased versus baseline in rats in the L group. A positive correlation to blood pressure was found for mesenteric artery wall thickness and wall: lumen ratio. Concentration for half-maximal effect for the response of mesenteric arteries from rats in the P group to norepinephrine was lower than that of the control group rats. Angiotensin II potentiated the norepinephrine-stimulated contraction of arteries from rats in the control and P groups, but not that of arteries from rats in the groups treated with L-158,809. CONCLUSION: Perindopril was more effective than was L-158,809 at lowering the blood pressure of adult spontaneously hypertensive rats, and at altering the structure and functioning of the arteries.