bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving realism of a surgery simulator: linear anisotropic elasticity, complex interactions and force extrapolation
Authors: Picinbono Guillaume , Lombardo Jean‐Christophe , Delingette Hervé , Ayache Nicholas 
Published: October 2002

AbstractIn this article, we describe the latest developments of the minimally invasive hepatic surgery simulator prototype developed at INRIA. The goal of this simulator is to provide a realistic training test bed to perform laparoscopic procedures. Therefore, its main functionality is to simulate the action of virtual laparoscopic surgical instruments for deforming and cutting tridimensional anatomical models. Throughout this paper, we present the general features of this simulator including the implementation of several biomechanical models and the integration of two force‐feedback devices in the simulation platform. More precisely, we describe three new important developments that improve the overall realism of our simulator. First, we have developed biomechanical models, based on linear elasticity and finite element theory, that include the notion of anisotropic deformation. Indeed, we have generalized the linear elastic behaviour of anatomical models to ‘transversally isotropic’ materials, i.e. materials having a different behaviour in a given direction. We have also added to the volumetric model an external elastic membrane representing the ‘liver capsule’, a rather stiff skin surrounding the liver, which creates a kind of ‘surface anisotropy’. Second, we have developed new contact models between surgical instruments and soft tissue models. For instance, after detecting a contact with an instrument, we define specific boundary constraints on deformable models to represent various forms of interactions with a surgical tool, such as sliding, gripping, cutting or burning. In addition, we compute the reaction forces that should be felt by the user manipulating the force‐feedback devices. The last improvement is related to the problem of haptic rendering. Currently, we are able to achieve a simulation frequency of 25 Hz (visual real time) with anatomical models of complex geometry and behaviour. But to achieve a good haptic feedback requires a frequency update of applied forces typically above 300 Hz (haptic real time). Thus, we propose a force extrapolation algorithm in order to reach haptic real time. Copyright © 2002 John Wiley & Sons, Ltd.
A survey on quality‐of‐service support for mobile ad hoc networks
Authors: Perkins Dmitri D. , Hughes Herman D. 
Published: October 2002

AbstractThe general field of mobile ad hoc networking is still in its infancy. Particularly, the challenge of providing Quality‐of‐Service (QoS) support for ad hoc networks is an open problem and remains relatively uncharted territory. Providing a complete QoS solution for the ad hoc networking environment requires the interaction and cooperation of several components. These components include: (1) a QoS routing protocol, (2) a resource reservation scheme and (3) a QoS capable medium access control (MAC) layer. In this paper, we present a survey of the current research that has addressed each of these components in the context of ad hoc networks. This work is intended to provide a broad and comprehensive view of the various components and protocols required to provide QoS support in computer networks, focusing primarily on ad hoc networks. First, we introduce the unique characteristics of mobile ad hoc networks, which distinguishing this new network architecture from traditional infrastructured wired and wireless networks (i.e. cellular‐based networks). We also discuss the impact of these characteristics on QoS provisioning. Next, we describe the first QoS model proposed for mobile ad hoc networks and its relationship to QoS models proposed for the Internet. We then present a review of the proposed algorithms for each QoS component (e.g. QoS routing, resource reservation and the MAC layer). Copyright © 2002 John Wiley & Sons, Ltd.
Long‐chain fatty acid uptake and oxidation in the perfused liver of Walker‐256 tumour‐bearing rats
Authors: Vicentino Christiame , Constantin Jorgete , Bracht Adelar , Yamamoto Nair Seiko 
Published: October 2002

Abstract: Aims/Background: The effect of the Walker‐256 tumour on uptake and oxidation of long‐chain fatty acids was investigated in perfused livers of rats.Methods: Isolated livers were perfused in a non‐recirculating system. Fatty acid uptake, ketogenesis, oxygen uptake and 14CO2‐production were measured as well as the activities of the acyl carnitine transferases I and II (CAT I and CAT II).Results: Basal oxygen uptake of livers from tumour‐bearing rats was lower. Ketone bodies production derived from the long‐chain fatty acids in livers from starved tumour‐bearing rats was lower relative to the controls, but 14CO2 production was similar in both groups. The oxygen uptake increment and the mitochondrial NADH/NAD+ redox ratio were also decreased in tumour‐bearing rats. The extent of these differences was dependent on the chain length and structure of the fatty acid, the following decreasing sequence of differences between control and tumour‐bearing animals being valid: palmitate > oleate > stearate. The CAT I activity of the enzyme isolated from livers of tumour‐bearing rats was half that from normal rats when palmitoyl‐CoA and oleoyl‐CoA were the substrates.Conclusions: Ketogenesis from exogenous fatty acids is decreased in the livers of Walker‐256 tumour‐bearing rats in consequence of the diminished activity of the mitochondrial CAT I. The lower rates of oxygen uptake indicate a decreased ATP synthesis, which is consistent with the in vivo lower phosphorylation potential.
Molecular and immunological characterization of a novel timothy grass (Phleum pratense) pollen allergen, Phl p 11
Authors: Marknell DeWitt Å. , Niederberger V. , Lehtonen P. , Spitzauer S. , Sperr W. R. , Valent P. , Valenta R. , Lidholm J. 
Published: October 2002

SummaryBackground Allergy to grass pollen is typically associated with serum IgE antibodies to group 1 and/or group 5 allergens, and additionally often to one or several less prominent allergens. Most of the grass pollen allergens identified to date have been characterized in detail by molecular, biochemical and immunological methods, timothy grass being one of the most thoroughly studied species. However, a 20‐kDa allergen frequently recognized by IgE antibodies from grass pollen allergics has so far escaped cloning and molecular characterization.Objective To clone and characterize the 20 kDa timothy grass pollen allergen Phl p 11.Methods Phl p 11 cDNA was cloned by PCR techniques, utilizing N‐terminal amino acid sequence obtained from the natural allergen. Phl p 11 was expressed as a soluble fusion protein in Escherichia coli, purified to homogeneity and used for serological analysis and to study Phl p 11 specific induction of histamine release from basophils and skin reactivity in sensitized and control subjects.Results Phl p 11 cDNA defined an acidic polypeptide of 15.8 kDa with homology to pollen proteins from a variety of plant species and to soybean trypsin inhibitor. The sequence contained one potential site for N‐linked glycosylation. Serological analysis revealed that recombinant Phl p 11 shared epitopes for human IgE antibodies with the natural protein and bound serum IgE from 32% of grass pollen‐sensitized subjects (n = 184). Purified recombinant Phl p 11 elicited skin reactions and dose‐dependent histamine release from basophils of sensitized subjects, but not in non‐allergic controls.Conclusion As the first representative of group 11 grass pollen allergens, Phl p 11 has been cloned and produced as a recombinant protein showing allergenic activity. One‐third of grass pollen‐sensitized subjects showed specific IgE reactivity to recombinant Phl p 11, corresponding in magnitude to a significant proportion of specific IgE to grass pollen extract.
House dust mites and their allergens at selected locations in the homes of house dust mite‐allergic patients
Authors: Sidenius K. E. , Hallas T. E. , Brygge T. , Poulsen L. K. , Mosbech H. 
Published: October 2002

SummaryBackground Knowledge of the occurrence of house dust mites (HDM) and their allergens in domestic locations is important when planning intervention.Objective The aim of this study was to describe the distribution of HDMs and their allergens before intervention in multiple locations in the homes of newly diagnosed HDM‐allergic patients with a known high Der 1 concentration in their mattress dust.Methods Dust was collected from ten locations in the homes of eight HDM‐allergic patients. Dust was analysed for allergen content with ELISAs for Der f 1, Der p 1 and Der m 1; and HDM were counted. Total allergen concentrations (µg Der 1/g dust) were expressed as the sum of Der f 1, Der p 1 and Der m 1.Results On mattresses the median concentration was 86 µg Der 1/g dust (range 30–288) and 188 mites/g dust (range 12–1910). Der 1 exceeded 10 µg/g dust in mattresses (8/8), duvets/pillows (3/8), a bedroom carpet (1/1), a living room carpet (1/6), upholstered furniture (2/8) and a curtain (1/5). Uncarpeted floors, upholstered furniture, bookshelves and walls had significantly lower Der 1 concentration than the mattresses. The relative contribution of Der p 1, Der f 1 or Der m 1 to Der 1 was related to homes, rather than to the location. Der m 1 only occurred in minute amounts.Conclusion For HDM intervention, our results indicate that priority should be given to the removal of allergens from mattresses, and in addition from carpets, duvets/pillows and upholstered furniture. Dust from walls, uncarpeted floors, bookshelves and curtains appear to contribute insignificantly to the domestic HDM allergen load.
The accuracy of the diagnosis of suspected paracetamol (acetaminophen) hypersensitivity: results of a single‐blinded trial
Authors: Kvedariene V. , Bencherioua A. M. , Messaad D. , Godard P. , Bousquet J. , Demoly P. 
Published: October 2002

SummaryBackground Hypersensitivity to paracetamol (acetaminophen) is rare and very few clinical data are available in the literature.Materials and methods Eighty‐four patients (28 males and 56 females, 5–70 years old) with a suspicion of paracetamol hypersensitivity were referred to our drug allergy clinic between May 1996 and May 2000. The reaction had occurred 1–96 months prior to the consultation. Single‐blinded placebo‐controlled oral challenges were carried out in 82 patients, under strict hospital surveillance.Results Most of the patients experienced skin eruptions 82/84 (97.6%), with 10 cases of anaphylactic shock (11.9%). Twenty‐six (30.9%) reactions were immediate (occurring within the first hour after drug intake), 53 (63.1%) non‐immediate and five could not remember. Oral provocation tests (OPT) demonstrated drug hypersensitivity in 11 patients only. The two patients not tested (due to a history of life‐threatening reaction) were included in the positive group. Thus, 13 (15.5%) patients had paracetamol hypersensitivity and 71 (84.5%) had not. All the 13 positive patients had skin eruptions, five with anaphylactic shock. 9/13 had immediate reactions. Using OPT, 10 out of 11 had the same clinical reaction but more delayed. In both groups, whether hypersensitive to paracetamol or not: atopy was similar (7/13–53.8% and 31/71–43.7%), sex ratio was not different (M/F 0.3 and 0.5), 3/13 (23.1%) and 0/71 (0%) had aspirin/ibuprofen hypersensitivity.Conclusion The clinical history of paracetamol (acetaminophen) hypersensitivity is rarely sufficient to set a firm diagnosis and only OPT can confirm this. Careful OPT reproduces the same symptoms (not more severe in our hands) with the same or slightly more delayed chronology. Atopy and sex are not risk factors.
Effect of ozone and nitrogen dioxide on the permeability of bronchial epithelial cell cultures of non‐asthmatic and asthmatic subjects
Authors: Bayram H. , Rusznak C. , Khair O. A. , Sapsford R. J. , Abdelaziz M. M. 
Published: October 2002

SummaryBackground Although epidemiological as well as in vivo exposure studies suggest that ozone (O3) and nitrogen dioxide (NO2) may play a role in airway diseases such as asthma, the underlying mechanisms are not clear.Objective Our aim was to investigate the effect of O3 and NO2 on the permeability of human bronchial epithelial cell (HBEC) cultures obtained from non‐atopic non‐asthmatic (non‐asthmatics) and atopic mild asthmatic (asthmatics) individuals.Methods We cultured HBECs from bronchial biopsies of non‐asthmatics and asthmatics, and exposed these for 6 h to air, 10 to 100 parts per billion (p.p.b.) O3, or to 100 to 400 p.p.b. NO2, and assessed changes in electrical resistance (ER) and movement of 14C‐BSA across the cell cultures.Results Although exposure to either O3 or NO2 did not alter the permeability of HBEC cultures of non‐asthmatics, 10 to 100 p.p.b. O3 and 400 p.p.b. NO2 significantly decreased the ER of HBEC cultures of asthmatics, when compared with exposure to air. Additionally, 10, 50 and 100 p.p.b. O3 led to a significant increase in the movement of 14C‐BSA across asthmatic HBEC cultures, after 6 h of exposure (medians = 1.73%; P < 0.01, 1.50%; P < 0.05 and 1.53%, P < 0.05, respectively), compared with air exposed cultures (median = 0.89%). Similarly, exposure for 6 h to both 200 and 400 p.p.b. NO2 significantly increased the movement of 14C‐BSA across asthmatic HBEC cultures, when compared with air exposure. A comparison of data obtained from the two study groups demonstrated that 10 to 100 p.p.b. O3‐ and 200 to 400 p.p.b. NO2‐induced epithelial permeability was greater in cultures of asthmatics compared with non‐asthmatics.Conclusion These results suggest that HBECs of asthmatics may be more susceptible to the deleterious effects of these pollutants. Whether in patients with asthma the greater susceptibility of bronchial epithelial cells to O3 and NO2 contributes to the development of the disease, or is a secondary characteristic of this condition, remains to be determined.
Use of a chimeric ELISA to investigate immunoglobulin E antibody responses to Der p 1 and Der p 2 in mite‐allergic patients with asthma, wheezing and/or rhinitis
Authors: Trombone A. P. F. , Tobias K. R. C. , Ferriani V. P. L. , Schuurman J. , Aalberse R. C. , Smith A. M. , Chapman M. D. , Arruda L. K. 
Published: October 2002

SummaryBackground Sensitization to indoor allergens, particularly to dust mites, is a strong risk factor for asthma in children and adults. Assessment of sensitization is carried out using in vivo and in vitro tests to detect specific IgE antibodies.Objective To investigate IgE antibody responses to mites in patients with asthma, wheezing and/or rhinitis, using chimeric ELISA to measure specific IgE antibodies to mite allergens Der p 1 and Der p 2.Methods Specific IgE antibodies to Der p 1 and Der p 2 were quantified by chimeric ELISA, and compared with IgE to Dermatophagoides pteronyssinus (Dpt) measured using the CAP system (Pharmacia). A panel of sera from 212 patients with asthma, wheezing and/or rhinitis and 11 controls was analysed.Results There was a significant correlation between IgE to Dpt measured by CAP and IgE to Der p 1 (r = 0.81, P < 0.001), Der p 2 (r = 0.79, P < 0.001) and combined Der p 1 and Der p 2 (r = 0.86, P < 0.001). Seventy per cent of all patients had IgE to Dpt, and of those, 76.5% had IgE to Der p 1, 79.2% had IgE to Der p 2 and 83.1% had IgE to Der p 1 and Der p 2 combined. Considering the cut‐off level of 2 IU/mL of IgE to either Der p 1 or Der p 2, the predictive value for a positive IgE to Dpt by CAP was greater than 95%.Conclusions The chimeric ELISA allowed accurate quantification of IgE antibodies to Dpt allergens Der p 1 and Der p 2, and it could be useful for studying immune responses to mites in patients with asthma and/or rhinitis.
Relationship between allergic rhinitis, disturbed cognitive functions and psychological well‐being
Authors: Kremer B. , Den Hartog H. M. , Jolles J. 
Published: October 2002

SummaryBackground Symptomatic allergic rhinitis reduces quality of life as a result of the symptoms experienced and possibly as a result of impaired psychological well‐being and cognitive functioning. Few investigations have measured cognitive functions objectively and it remains uncertain whether allergic rhinitis leads to an objective reduction in cognitive functions.Objective To evaluate the relationship between symptomatic allergic rhinitis, cognitive functions and psychological well‐being. Differences between subjective and objective cognitive impairments were evaluated.Methods The cognitive functions (working memory, memory retrieval, speed of information processing and flexibility of information processing) and psychological well‐being of 26 patients with symptomatic allergic rhinitis and 36 healthy controls matched for intelligence, education, age and sex were compared. The influence of education, intelligence, sex and age was considered.Results Overall, psychological well‐being was significantly impaired in the patient group, as shown by higher scores in feelings of insufficiency, complaints of somatization, sleep disturbances and depressive feelings, whereas cognitive function was not.Conclusions Allergic rhinitis was related to significantly impaired psychological well‐being and to perceived impaired cognitive functioning. However, no significant objective impairment of cognitive functioning was found. Allergic patients may temporarily put more effort into sustaining performance, resulting in earlier exhaustion, which is not noticed during assessment but which impairs psychological well‐being.
The relation between accommodative facility and general binocular dysfunction
Authors: Garcı´a Ángel , Cacho Pilar , Lara Francisco , Megı´as Ramón 
Published: October 2002

SummaryThis study was designed to evaluate the relation between accommodative facility and accommodative and binocular dysfunctions. We determined whether failure to achieve 8 cycles per minute of binocular accommodative facility or 11 cycles per minute of monocular accommodative facility tends to be associated with these dysfunctions. Forty eight subjects, ages 10–30 years were examined and classified into four groups: 13 subjects with accommodative dysfunctions, 11 patients with binocular dysfunctions, 12 subjects with accommodative and binocular dysfunctions and 12 control subjects with refractive errors but no accommodative or binocular anomalies. Monocular and binocular accommodative facility was conducted using ±2.00 D flip lenses. In general, statistical analysis indicates that subjects with binocular and accommodative (ocular motor) anomalies performed significantly poorer than subjects of normal group on monocular and binocular facility tests. Monocular accommodative facility results showed more information about the dysfunction of the patient compared with the results of the binocular accommodative facility. In general data supported a relation between reduced accommodative facility and a general binocular dysfunction (accommodative or binocular) which demonstrates the importance of the accommodative facility test in diagnosing an accommodative or binocular anomaly.
The practical near acuity chart (PNAC) and prediction of visual ability at near1
Authors: Wolffsohn James S. , Cochrane Anthea L. 
Published: October 2002

Summary Objective: To improve on present reading chart designs, providing a quick and accurate method to measure the near acuity threshold, of particular importance with low vision patients. Design: The Practical Near Acuity Chart (PNAC) uses a single paragraph with 3 simple related words on each line (12 lower case letters). The line print size decreases in a logMAR progression (N80‐N5). Methods: The time taken to measure near acuity of 53 subjects aged 9–91 years with the PNAC and Bailey–Lovie near chart was recorded and compared to their distance acuity (Bailey–Lovie chart), contrast sensitivity (Melbourne Edge Test) and ability to read extracts of newsprint. Results: There was no difference in near acuity threshold using related or un‐related words. There was a high correlation (r=0.97) between near acuity measured with the PNAC and Bailey–Lovie charts. However, the time taken to measure near acuity was significantly faster with the PNAC (32±2 s vs 76±4 s, p<0.001). Near acuity measured with either chart was highly correlated (p<0.001) to distance acuity (r=0.74), contrast sensitivity (r=0.62) and ability to read newsprint (r=0.87). The PNAC was shown to have high test‐reliable (r=0.99). Conclusions: The PNAC offers a quick but accurate way to measure near acuity and shows a high degree of correlation with distance acuity, contrast sensitivity and the ability to read newsprint.
Precision of autokeratometry expressed as confidence ellipses in Euclidian 2‐space
Authors: Naeser Kristian , Guo Suping 
Published: October 2002

SummaryA number of studies have examined the repeatability or precision of keratometers. All studies have found exceptionally high precision in keratometry of the spherically equivalent proportion, while the joint variation in astigmatic direction and magnitude barely has been explored. The purpose of this study was to examine the simultaneous variation in astigmatic direction and magnitude between two single autokeratometries, using a Nidek ARK 2000‐S autokeratorefractometer.A single autokeratometry was performed on two occasions on 50 right eyes of patients with cataracts. The precision was defined as the paired difference between these two measurements. Each net astigmatism was transformed to polar values, and uni‐ and bivariate polar value analysis was performed.Precision of autokeratometry, expressed as a mean difference and a 95% confidence area, was calculated as a confidence ellipse in Euclidian 2‐space. The accompanying net astigmatisms with confidence perimeters were derived by point‐for‐point transformation from polar values.Clinical variability may overwhelmingly be attributed to patient‐related factors and only to a small degree to autokeratometry itself. Clinicians should know the precision of their keratometers, both for daily use and in the planning and dimensioning of scientific studies. Our results indicate that a minimum number of 25 eyes in each group is necessary in order to detect a difference of 0.25 diopters in surgically induced astigmatism between two surgical techniques. Precision of keratometry can only be determined from polar values or similar entities and never by the use of net astigmatisms.
Evidence that a gender difference in intraocular pressure is present from childhood
Authors: Pointer Jonathan S. 
Published: October 2002

SummaryRoutine assessment of intraocular pressure (IOP) is usually confined to the clinical population aged over 40 years, i.e., to those individuals considered to be most at‐risk of developing glaucoma. Published IOP data collected from assumed non‐glaucomatous adult subjects have shown a gender difference in this parameter, with human females recording a consistently higher value than age‐matched males. A recent study has also demonstrated that a diurnal variation in IOP can be recorded in adults across normal consulting hours. IOP material is presented here, as collected in the early afternoon (14.00–14.59 hours) from n=140 school children aged ≥9<12 years. It is complemented by previously published data, also recorded between 14.00–14.59, from n=100 middle‐aged adults aged 40–59 years, and n=102 mature adults aged over 60 years. Analysis of these three data sets indicates that a non‐statistically significant gender difference in mean IOP (female>male) is present from childhood; it also suggests that, for either gender, the absolute mean level of IOP remains little altered from childhood into and throughout adulthood. However the physiological basis for these observations remains obscure.