Robotic control in knee joint replacement surgery

A brief history of robotic systems in knee arthroplasty is provided. The place of autonomous robots is then discussed and compared to more recent 'hands-on' robotic systems that can be more cost effective. The case is made for robotic systems to have a clear justification, with improved benefits compared to those from cheaper navigation systems. A number of more recent, smaller, robot systems for knee arthroplasty are also described. A specific example is given of an active constraint medical robot, the ACROBOT system, used in a prospective randomized controlled trial of unicondylar robotic knee arthroplasty in which the robot was compared to conventional surgery. The results of the trial are presented together with a discussion of the need for measures of accuracy to be introduced so that the efficacy of the robotic surgery can be immediately identified, rather than have to wait for a number of years before long-term clinical improvements can be demonstrated.     

Integral-based filtering of continuous glucose sensor measurements for glycaemic control in critical care

Hyperglycaemia is prevalent in critical illness and increases the risk of further complications and mortality, while tight control can reduce mortality up to 43%. Adaptive control methods are capable of highly accurate, targeted blood glucose regulation using limited numbers of manual measurements due to patient discomfort and labour intensity. Therefore, the option to obtain greater data density using emerging continuous glucose sensing devices is attractive. However, the few such systems currently available can have errors in excess of 20-30%. In contrast, typical bedside testing kits have errors of approximately 7-10%. Despite greater measurement frequency larger errors significantly impact the resulting glucose and patient specific parameter estimates, and thus the control actions determined creating an important safety and performance issue. This paper models the impact of the continuous glucose monitoring system (CGMS, Medtronic, Northridge, CA) on model-based parameter identification and glucose prediction. An integral-based fitting and filtering method is developed to reduce the effect of these errors. A noise model is developed based on CGMS data reported in the literature, and is slightly conservative with a mean Clarke Error Grid (CEG) correlation of R=0.81 (range: 0.68-0.88) as compared to a reported value of R=0.82 in a critical care study. Using 17 virtual patient profiles developed from retrospective clinical data, this noise model was used to test the methods developed. Monte-Carlo simulation for each patient resulted in an average absolute 1-h glucose prediction error of 6.20% (range: 4.97-8.06%) with an average standard deviation per patient of 5.22% (range: 3.26-8.55%). Note that all the methods and results are generalizable to similar applications outside of critical care, such as less acute wards and eventually ambulatory individuals. Clinically, the results show one possible computational method for managing the larger errors encountered in emerging continuous blood glucose sensors, thus enabling their more effective use in clinical glucose regulation studies.     

Sterol and steryl ester regulation of phospholipase A2 from the mosquito parasiteLagenidium giganteum

Lagenidium giganteum, a facultative parasite of mosquito larvae, cannot synthesize sterols, and requires an exogenous source of these lipids in order to enter its reproductive cycle. This parasite grows vegetatively in the absence of sterols, but requires cholesterol or structurally related compounds to produce motile zoospores, which are the only stage capable of infecting mosquitoes. Sterols structurally related to cholesterol and some steryl esters inhibited the activity ofL. giganteum phospholipase A₂ (PLA₂), an enzyme that hydrolyzes fatty acids from thesn-2 position of glycerophospholipids. Sterols that induce reproduction inhibitedL. giganteum PLA₂ activity, while sterols and steroids that do not support sporulation had minimal effect. Most steryl esters had no effect on enzyme activity, but cholesteryl arachidonate (CA) was a potent inhibitor of parasite PLA₂. Not all enzymes partly purified using a DEAE-Sephacel column were affected by these lipids, demonstrating selective inhibition of specific enzymes. Potency was enhanced by up to several orders of magnitude if epoxy fatty acids were esterified to the cholesterol nucleus. The steryl ester pool was dynamic during morphogenesis, and the fatty acid composition of the steryl esters did not mimic total cell or membrane (glycerophospholipid) fatty acid composition asL. giganteum proceeded through its growth cycle. Synthesis of CA and monoepoxy CA by the parasite was confirmed using electrospray mass spectrometry and collision-induced dissociation. Steryl derivatives selectively inhibited PLA₂ enzymes from bovine pancreas, snake venom, and human cytoplasmic 85-kDa PLA₂.     

Miconazole per os in tinea and deep mycosis

For the last 6 years we have been using Miconazole cream in the treatment of tinea and vaginal candidiasis. We think that it is at least as good as the best drugs for this purpose, but consider it difficult to decide about its superiority. Therefore we refrain from describing this part of our experience in detail. We have employed Miconazole "per os" at the daily doses of 24-28 mg./kg. in treating 3 cases of tinea corporis or cruris by "Trichophyton rubrum". Symptoms ceased in 3 days; mycologic examination turned negative in 2 weeks; treatment ended in apparent cure in 3 weeks. We have employed Miconazole "per venam" and "per os" in the treatment of: mycetomata (2) by "Streptomyces somaliensis", without success; mycetoma by "Madurella grisea" (1), without success; chromomycosis by a 5-flucytosine resistant strain of "Cladosporium carrionii" (1), without success; paracoccidioidosis (5) with lesions in mouth and lungs, with good results; leishmaniasis by "Leishmania brasiliensis" (1), without success; mucocutaneous disseminated candidiasis (1), with very good results. Tolerance has been excellent: but pruritus appeared from the third week with 600 or more mg. "per venam", in several patients. Doses varied between 10 and 50 mg./kg./day. One patient, who suffered with candidiasis, is taking 50 to 30 mg./kg./day since more than a year ago and, being a child, he is feeling well and growing to be normal. We recommend employing Miconazole against systemic canidiasis, sulpharesistant paracoccidioidosis and assaying it further in tinea (at least, in griseofulvin-resistant cases).     

RX64DTH -a fully integrated 64-channel ASIC for a digital X-ray imaging system with energy window selection

We report on the multichannel IC (RX64DTH) designed for position sensitive X-ray measurements with silicon strip detectors and dedicated to medical imaging applications. This integrated circuit has a binary readout architecture with a double threshold allowing on selection energy window for measured signals. The design was realized in a 0.8 /spl mu/m CMOS process. The core of the RX64DTH IC consists of 64 readout channels. The single channel is built with four basic blocks: charge sensitive preamplifier, shaper, two independent discriminators, and two independent 20-bit counters. Each readout channel counts pulses which are above the low discriminator threshold and counts pulses independently above the high discriminator threshold. The energy resolution in such architecture is limited by the noise of a single channel and by channel to channel threshold spread. We present the noise and matching performance of a 384-channel module built with a silicon strip detector and six RX64DTH ICs. In the 384-channel module an equivalent noise charge of about 200 el. rms is achieved for the shaper peaking time of 0.8 /spl mu/s and strip capacitance of 3 pF. The deviation of discriminator thresholds for the whole system is only 87 el. rms. The obtained results show that the energy resolution and uniformity of analog parameters (noise, gain, offset) are sufficient for medical diagnostic applications such as dual energy mammography and angiography.     

Gas-sensing properties of sprayed films of (CdO)/sub x/(ZnO)/sub 1-x/ mixed oxide

A novel NO/sub 2/ sensor based on (CdO)/sub x/(ZnO)/sub 1-x/ mixed-oxide thin films deposited by the spray pyrolysis technique is developed. The sensor response to 3-ppm NO/sub 2/ is studied in the range 50/spl deg/C-350/spl deg/C for three different film compositions. The device is also tested for other harmful gases, such as CO (300 ppm) and CH/sub 4/ (3000 ppm). The sensor response to these reducing gases is different at different temperatures varying from the response typical for the p-type semiconductor to that typical for the n-type semiconductor. Satisfactory response to NO/sub 2/ and dynamic behavior at 230/spl deg/C, as well as low resistivity, are observed for the mixed-oxide film with 30% Cd. The response to interfering gas is poor at working temperature (230/spl deg/C). On the basis of this study, a possible sensing mechanism is proposed.     

Statistical Pattern Modeling in Vision-Based Quality Control Systems

Machine vision technology improves productivity and quality management and provides a competitive advantage to industries that employ this technology. In this article, visual inspection and quality control theory are combined to develop a robust inspection system with manufacturing applications. The inspection process might be defined as the one used to determine if a given product fulfills a priori specifications, which are the quality standard. In the case of visual inspection, these specifications include the absence of defects, such as lack (or excess) of material, homogeneous visual aspect, required color, predetermined texture, etc. The characterization of the visual aspect of metallic surfaces is studied using quality control chars, which are a graphical technique used to compare on-line capabilities of a product with respect to these specifications. Original algorithms are proposed for implementation in automated visual inspection applications with on-line execution requirements. The proposed artificial vision method is a hybrid between the two usual methods of pattern comparison and theoretical decision. It incorporates quality control theory to statistically model the pattern for defect-free products. Specifically, individual control charts with 6-sigma limits are set so the inspection error is minimized. Experimental studies with metallic surfaces help demonstrate the efficacy and robustness of the proposed methodology.     

Robotized spraying of prefabricated panels

A robotic manufacturing cell of pre-fabricated glass reinforced cement panels for construction industry has been developed by DISAM for the Spanish construction company Dragados, SA. The main contribution of the developed system is the automatic programming and control of the whole plan. The architect's 3D-drawing of the building facade done on a CAD system serves as input. From the CAD design, the optimum facade to panels partition is obtained. In order to manufacture each panel, automatic task and path planning are performed for the equipment present in the manufacturing cell: spraying robot, PLCs, control computer, etc     

A Color Vision-Based Lane Tracking System for Autonomous Driving on Unmarked Roads

This work describes a color Vision-based System intended to perform stable autonomous driving on unmarked roads. Accordingly, this implies the development of an accurate road surface detection system that ensures vehicle stability. Although this topic has already been documented in the technical literature by different research groups, the vast majority of the already existing Intelligent Transportation Systems are devoted to assisted driving of vehicles on marked extra urban roads and highways. The complete system was tested on the BABIECA prototype vehicle, which was autonomously driven for hundred of kilometers accomplishing different navigation missions on a private circuit that emulates an urban quarter. During the tests, the navigation system demonstrated its robustness with regard to shadows, road texture, and weather and changing illumination conditions.     

Parameter estimation in Bayesian reconstruction of SPECT images: An aid in nuclear medicine diagnosis

Despite the adequacy of Bayesian methods to reconstruct nuclear medicine SPECT (single‐photon emission computed tomography) images, they are rarely used in everyday medical practice. This is primarily because of their computational cost and the need to appropriately select the prior model hyperparameters. We propose a simple procedure for the estimation of these hyperparameters and the reconstruction of the original image and test the procedure on both synthetic and real SPECT images. The experimental results demonstrate that the proposed hyperparameter estimation method produces satisfactory reconstructions. Although we have used generalized Gaussian Markov random fields (GGMRF) as prior models, the proposed estimation method can be applied to any priors with convex potential and tractable partition function with respect to the scale hyperparameter. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 21–27, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20003