Modeling of the Influence of Operational Parameters on Tire Lateral Dynamics.

Tires play a critical role in vehicle safety. Proper modeling of tire-road interaction is essential for optimal performance of active safety systems. This work studies the influence of temperature, longitudinal vehicle speed, steering frequency, vertical load, and inflation pressure on lateral tire dynamics. To this end, a tire test bench that allows the accurate control of these parameters and the measurement of the variables of interest was used. The obtained results made it possible to propose a simple model that allowed the determination of relaxation length as a function of tire vertical load and vehicle linear speed, and the determination of a representative tread temperature. Additionally, a model has been proposed to determine the lateral friction coefficient from the aforementioned temperature. Finally, results also showed that some variables had little influence on the parameters that characterize lateral dynamics.

A Novel Method for Determining Angular Speed and Acceleration Using Sin-Cos Encoders.

The performance of vehicle safety systems depends very much on the accuracy of the signals coming from vehicle sensors. Among them, the wheel speed is of vital importance. This paper describes a new method to obtain the wheel speed by using Sin-Cos encoders. The methodology is based on the use of the Savitzky-Golay filters to optimally determine the coefficients of the polynomials that best fit the measured signals and their time derivatives. The whole process requires a low computational cost, which makes it suitable for real-time applications. This way it is possible to provide the safety system with an accurate measurement of both the angular speed and acceleration of the wheels. The proposed method has been compared to other conventional approaches. The results obtained in simulations and real tests show the superior performance of the proposed method, particularly for medium and low wheel angular speeds.

Low-Cost Road-Surface Classification System Based on Self-Organizing Maps.

Expanding the performance and autonomous-decision capability of driver-assistance systems is critical in today's automotive engineering industry to help drivers and reduce accident incidence. It is essential to provide vehicles with the necessary perception systems, but without creating a prohibitively expensive product. In this area, the continuous and precise estimation of a road surface on which a vehicle moves is vital for many systems. This paper proposes a low-cost approach to solve this issue. The developed algorithm resorts to analysis of vibrations generated by the tyre-rolling movement to classify road surfaces, which allows for optimizing vehicular-safety-system performance. The signal is analyzed by means of machine-learning techniques, and the classification and estimation of the surface are carried out with the use of a self-organizing-map (SOM) algorithm. Real recordings of the vibration produced by tyre rolling on six different types of surface were used to generate the model. The efficiency of the proposed model (88.54%) and its speed of execution were compared with those of other classifiers in order to evaluate its performance.

Low-Cost FPGA-Based Electronic Control Unit for Vehicle Control Systems.

The development of new control algorithms in vehicles requires high economic resources, mainly due to the use of generic real-time instrumentation and control systems. In this work, we proposed a low-cost electronic control unit (ECU) that could be used for both development and implementation. The proposed electronic system used a hybrid system on chip (SoC) between a field-programmable gate array (FPGA) and an Advanced RISC (reduced instruction set computer) Machine (ARM) processor that allowed the execution of parallel tasks, fulfilling the real-time requirements that vehicle controls demand. Another feature of the proposed electronic system was the recording of measured data, allowing the performance of the implemented algorithm to be evaluated. All this was achieved by using modular programming that, without the need for a real-time operating system, executed the different tasks to be performed, exploiting the parallelism offered by the FPGA as well as the dual core of the ARM processor. This methodology facilitates the transition between the designing, testing, and implementation stages in the vehicle. In addition, our system is programmed with a single binary file that integrates the code of all processors as well as the hardware description of the FPGA, which speeds up the updating process. In order to validate and demonstrate the performance of the proposed electronic system as a tool for the development and implementation of control algorithms in vehicles, a series of tests was carried out on a test bench. Different traction control system (TCS) algorithms were implemented and the results were compared.

Influence of TFAP2B and KCTD15 genetic variability on personality dimensions in anorexia and bulimia nervosa.

INTRODUCTION: TFAP2B and KCTD15 are obesity-related genes that interact to regulate feeding behavior. We hypothesize that variability in these loci, isolated or in combination, could also be related to the risk of eating disorders (ED) and/or associated psychological traits. METHODS: We screened 425 participants (169 ED patients, 75 obese subjects, and 181 controls) for 10 clinically relevant and tag single-nucleotide polymorphisms (SNPs) in KCTD15 and TFAP2B by the Sequenom MassARRAY platform and direct sequencing. Psychometric evaluation was performed with EDI-2 and SCL-90R inventories. RESULTS: The KCTD15 rs287103 T variant allele was associated with increased risk of bulimia nervosa (BN) (OR = 4.34 [1.47-29.52]; p = .003) and with scores of psychopathological scales of these patients. Haplotype *6 in KCTD15 was more frequent in controls (OR = 0.40 [0.20-0.80], p = .009 for anorexia nervosa), while haplotype *4 in TFAP2B affected all three scales of the SCL-90R inventory in BN patients (p ≤ .01). Epistasis analyses revealed relevant interactions with body mass index of BN patients (p < .001). Genetic profiles in obese patients did not significantly differ from those found in ED patients. CONCLUSIONS: This is the first study that evaluates the combined role of TFAP2B and KCTD15 genes in ED. Our preliminary findings suggest that the interaction of genetic variability in these loci could influence the risk for ED and/or anthropometric and psychological parameters.

Melanocortin-4 receptor gene variants are not associated with binge-eating behavior in nonobese patients with eating disorders.

We aimed to determine whether variability in the melanocortin-4 receptor (MC4R) gene, predisposing to hyperphagia and obesity, may also be present in nonobese patients with binge-eating behavior or be related to anthropometric or psychopathological parameters in these patients. The coding region of the MC4R gene was sequenced in nonobese patients with binge-eating behavior diagnosed with bulimia nervosa or binge-eating disorder (n=77); individuals with severe early-onset obesity (n=170); and lean women with anorexia nervosa (n=20). A psychometric evaluation (Eating Disorders Inventory-2 and Symptom Checklist 90 Revised inventories) was carried out for all the patients with eating disorders. In the obesity group, 10 different variants were identified, whereas in the binge-eating patients, only two individuals with bulimia nervosa were found to carry the I251L polymorphism, which did not correlate with weight, BMI, or psychopathological features. We found no evidence that mutations in the MC4R gene are associated with binge-eating behavior in nonobese eating disorder patients.

Comparative cytochrome p450 in vitro inhibition by atypical antipsychotic drugs.

The goal of this study was to assess in human liver microsomes the inhibitory capacity of commonly used antipsychotics on the most prominent CYP450 drug metabolizing enzymes (CYP1A2, CYP2C9, CYP2D6, and CYP3A). Chlorpromazine was the only antipsychotic that inhibited CYP1A2 activity (IC50 = 9.5 µ M), whilst levomepromazine, chlorpromazine, and thioridazine significantly decreased CYP2D6-mediated formation of 1'-hydroxybufuralol (IC50 range, 3.5-25.5 µ M). Olanzapine inhibited CYP3A-catalyzed production of 1', and 4'-hydroxymidazolam (IC50 = 14.65 and 42.20 µ M, resp.). In contrast, risperidone (IC50 = 20.7 µ M) and levomepromazine (IC50 = 30 µ M) showed selectivity towards the inhibition of midazolam 1'-hydroxylation reaction, and haloperidol did so towards 4'-hydroxylation (IC50 of 2.76 µ M). Thioridazine displayed a Ki of 1.75 µ M and an inhibitory potency of 1.57 on CYP2D6, suggesting a potential to induce in vivo interactions. However, with this exception, and given the observed Ki values, the potential of the assayed antipsychotics to produce clinically significant inhibitions of CYP450 isoforms in vivo seems limited.

Using a computerized drug prescription screening system to trace drug interactions in an outpatient setting.

BACKGROUND: Drug-drug interactions are one of the main causes of adverse effects. These events have been studied most often in hospital settings; however, investigations on prescribing based on community practice have shown a high prevalence rate of potential drug interactions. OBJECTIVE: To develop a computerized system able to trace drug interactions quickly through the identification of clinicians issuing potentially unsafe prescriptions. METHODS: We retrospectively evaluated hazardous concomitant prescriptions of hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) and azole antifungals, which were invoiced through 9 months of 2001 within an outpatient setting. The study was conducted in Badajoz, a southern Spanish province, and was divided in three 3-month periods according to the release of 2 warning notes on this drug combination by the Spanish Drug Agency. Prescriptions written during this period were optically scanned each month, and the resulting information, including data from patients, physicians, and drugs involved, was converted to a database and searched for potentially unsafe coprescriptions. RESULTS: A total of 8342711 prescriptions were invoiced in the period of study, 174 of which were for a statin-azole combination. The number of these prescriptions remained fairly constant during periods I and II (63 and 71, respectively), decreasing to 40 in period III. Some clinicians (12.6%) repeatedly prescribed a hazardous drug combination at some point in this study, whereas 18 of 171 patients who received the hazardous coprescription at any time did so repeatedly within a given period. The impact of drug alerts was remarkably deeper in urban rather than rural care centers. CONCLUSIONS: The computerized drug prescription handling system described here is able to readily identify physicians and patients who issue/consume hazardous drug combinations, thus allowing both the possibility of individually informing the healthcare professionals involved and early detection of adverse effects.

Early detection of drug interactions utilizing a computerized drug prescription handling system-focus on cerivastatin-gemfibrozil.

OBJECTIVES: Based on the recent cerivastatin experience, we retrospectively evaluated the effect of notifying a drug alert utilizing a computerized drug-handling system. METHODS: The evaluation was carried out during three periods: period I corresponded to all prescriptions issued during April, 2001 ("baseline period"), before the Spanish Drug Agency issued alerts on the concomitant therapy with cerivastatin and gemfibrozil; period II (June) corresponded to a time in which a first informative note had been released; and period III (July) after the second warning alert was issued. RESULTS: Data collected included the reading of 2,693,656 drug prescriptions, 1,937,083 (71.9%) of which contained patient information. Forty-four patients received combined therapy with cerivastatin and gemfibrozil over the three periods, yielding 55 exposures: 27 during the baseline period, and 28 between periods II and III, when the alert bulletins had already been released. Moreover, 41.6% of doctors included in the follow-up repeated the hazardous prescription during those two periods. CONCLUSIONS: The effect of the informative notes about the risk of prescribing cerivastatin and gemfibrozil concomitantly on doctors' prescribing habits was limited. The system for screening information from drug prescriptions presented herein allows the early detection of drug interactions by identifying the doctors who issue hazardous prescriptions as well as patients at the highest risk of adverse drug reactions, thus allowing a personal feedback with both of them.