Camcorders

The author explains from an engineering standpoint, how some of the camcorder components work. He discusses the solid-state image sensor, the photodetector, scanning, the shutter frame rate, optics, the recording mechanism, the viewfinder, special effects, and automatic features. Motion detection, discrimination, and compensation are also covered. Recommendations as to which features are most useful are made     

Linkage between inflammation and coagulation: an update on the molecular basis of the crosstalk

Inflammation and coagulation cannot be considered as two separate processes, since there are several connecting points making them part of unique, defensive host response. The endothelium can be considered as the first link between inflammation and coagulation, since damaged endothelium during inflammation represents a surface where proteins involved in both coagulation and the development of inflammation are expressed. During inflammation, cytokines modulate the coagulation system by downregulating the expression of thrombomodulin and the activation of protein C pattern but, at the same time, they induce the expression of tissue factor, modifying, in this way, the balance between procoagulant and anticoagulant activities. At the same time, at the site of tissue injury, platelets become activated and release several mediators that modify tissue integrity. Thrombin, formed following activation of the coagulation cascade, is essential to promote haemostasis but also stimulates several cell functions, including chemotaxis and mitogenesis, which are responsible for the spreading of the lesion and the tissue repair process. Therefore, in the study of inflammation the involvement of the coagulation pathway has to be taken into account, since the interaction between coagulation and inflammation pathways is a critical issue.     

Differential therapy of cerebral arteriovenous malformations. An analysis with reference to personal microsurgery experiences

A total of 126 patients (63 female, 63 male) underwent microsurgical removal of their cerebral arteriovenous malformations (AVMs) by the same surgeon. The mean age at surgery was 34.7 (6-72) years. The symptoms were intracerebral hemorrhage (37.3%), seizure disorder (34.9%) or focal neurological deficits and minor symptoms. According to the Spetzler/Martin scale, 20.6% of the AVMs were grade I, 28.6% grade II, 32.5% grade III, 14.3% grade IV and 4% grade V. In all, 78 AVMs (61.9%) were located in functionally important brain regions. The series was split into three different groups: small AVMs under 3 cm in diameter (n = 62/49.2%), medium-sized AVMs (n = 58/46%) and large AVMs (n = 6/4.8%). Seventeen patients had preoperative embolization of their AVM. All patients had postoperative angiographic control and 3- and 6-month follow-up. One patient died (0.8%), and another one (0.8%), in whom the AVM was incompletely resected, suffered a secondary hemorrhage. Seventeen (27.4%) of the patients with small AVMs developed transient neurological worsening post-operatively, which remained permanently significant in 3.2%. The respective numbers for the patients with medium-sized AVMs were 48.3% and 10.3% and for the large AVMs 83.3% and 33.3%. The results of microsurgical removal of cerebral AVMs can still be considered superior to the results of stereotactic radiosurgical treatment available from the literature-even for small AVMs. This is due to immediate exclusion of the AVM under direct local control of the angioarchitecture and thereby a reduced risk of secondary hemorrhaging and a decreasing morbidity rate with increasing time after the operation. Radiosurgical treatment requires a 2-year latency period for obliteration and carries a mortality rate of up to 12.5% and a rate of unexpected side effects of up to 20%. This treatment should be reserved for small, deep, surgically inaccessible AVMs or used as part of a multimodality treatment regimen consisting of partial embolization, partial excision and consecutive radiation of the residual nidus in initially very large AVMs. Embolization therapy-such as radiosurgery-carries a significant risk of morbidity (8%) and a mortality rate of up to 6%. It should only be considered for AVMs that are expected to be fully obliterated afterwards, or for primary inoperable AVMs that are to be changed into operable ones by embolization. Size reduction of otherwise operable AVMs does not justify the additional risk of embolization. Close collaboration of the specialties involved is desirable.     

Comparison of smoothness evaluation devices for power cablecompounds

A variety of data from different devices has been generated on the smoothness of shield products, but no direct comparison of compound smoothness for the devices themselves has been made. The purpose of this study was to compare four different methods for evaluating the smoothness of power cable compounds. The methods compared include: image analysis, laser scanning, mechanical profilometry and photomicroscopy with visual rating. Extruded tape samples of conductor shields, filled insulations and strippable shields were evaluated     

Consumption of reduced-fat products: effects on parameters of anti-oxidative capacity

Plasma levels of fibrinogen, factor VIIc and prothrombin fragment F1 + 2, a marker of thrombin generation in vivo, were studied in 68 subjects with serum total cholesterol (TC) levels between 135 and 349 mg/dl but without clinical evidence of cardiovascular disease and other atherosclerotic risk factors. F1 + 2 plasma levels were directly correlated with TC (p < 0.0004), low-density lipoprotein cholesterol (LDL-C; p < 0.0018) and factor VIIc (p < 0.024). Thirty-five subjects with TC greater than 249 mg/dl (median value of the whole group) showed higher levels of F1 + 2 (p < 0.0001) and fibrinogen (p < 0.0015) than those with TC lower than 249 mg/dl. In subjects with TC > 249 mg/dl and F1 + 2 > 1.2 nM (median value of the whole group), a cholesterol-lowering drug (simvastatin) was able to reduce F1 + 2 (p < 0.009) as well as TC and LDL-C. This study shows a relationship between serum cholesterol and the rate of thrombin generation supporting the hypothesis that a hypercoagulable state may occur in hypercholesterolemic subjects before the onset of clinical evidence of atherosclerotic cardiovascular disease.     

On Toroidal Azulenoids and Other Shapes of Fullerene Cage

The possibility of toroidal cages of carbon with repeating five and seven membered ring pairs (azulene units) upon their surfaces is briefly discussed. Some of the difficulties in recognising possible fullerene cage shapes are pointed out.     

ACT3: a high-speed, high-precision electrical impedance tomograph

Presents the design, implementation, and performance of Rensselaer's third-generation adaptive current tomograph, ACT3. This system uses 32 current sources and 32 phase-sensitive voltmeters to make a 32-electrode system that is capable of applying arbitrary spatial patterns of current. The instrumentation provides 16 b precision on both the current values and the real and reactive voltage readings and can collect the data for a single image in 133 ms. Additionally, the instrument is able to automatically calibrate its voltmeters and current sources and adjust the current source output impedance under computer control. The major system components are discussed in detail and performance results are given. Images obtained using stationary agar targets and a moving pendulum in a phantom as well as in vivo resistivity profiles showing human respiration are shown     

Seismic response of structures with supplemental damping

This paper presents a review of supplemental damping devices used for the control of the seismic response of structures. The mechanical properties of these devices are discussed and considerations in the design of energy absorbing systems are presented.