SUMCOR: Cascade summing correction for volumetric sources applying MCNP6.

The main features of code SUMCOR developed for cascade summing correction for volumetric sources are described. MCNP6 is used to track histories starting from individual points inside the volumetric source, for each set of cascade transitions from the radionuclide. Total and FEP efficiencies are calculated for all gamma-rays and X-rays involved in the cascade. Cascade summing correction is based on the matrix formalism developed by Semkow et al. (1990). Results are presented applying the experimental data sent to the participants of two intercomparisons organized by the ICRM-GSWG and coordinated by Dr. Marie-Cristine Lépy from the Laboratoire National Henri Becquerel (LNE-LNHB), CEA, in 2008 and 2010, respectively and compared to the other participants in the intercomparisons.

Allergic sensitization to laboratory animals is more associated with asthma, rhinitis, and skin symptoms than sensitization to common allergens.

BACKGROUND: Workers exposed to laboratory animals have a high risk of developing laboratory animal allergy (LAA). Atopy seems to be the main risk factor for LAA. We hypothesized that occupational sensitization is a better predictor for the development of asthma, rhinitis, and bronchial hyperresponsiveness (BHR) than common sensitization. OBJECTIVE: To investigate the association between occupational sensitization to laboratory animals and clinical outcomes. METHODS: This was a cross-sectional study performed at two universities on students and employees dealing with small rodents. The subjects were allocated in groups: non-sensitized, common sensitization, or occupational sensitization, according to the results of the skin prick test (SPT). All subjects answered a questionnaire about animal exposures, symptoms, allergic diseases, and underwent spirometry and bronchial challenge test with mannitol. Multivariate analysis was performed using Poisson regression to estimate the prevalence ratio (PR). RESULTS: Data from 453 volunteers were analysed. Non-sensitized group comprised 237 subjects; common sensitization group, 142 subjects; and occupational sensitization group, 74 subjects. Occupational sensitization was associated with greater risk for all outcomes studied. When the common sensitization group was reference, skin symptoms had PR of 1.36, 95% confidence interval (CI): 1.01-1.85; wheezing had PR of 1.75, CI 95%: 1.21-2.53; rhinitis had PR of 1.25, 95%: 1.11-1.40; nocturnal dyspnoea had PR of 2.40, 95% CI: 1.31-4.40; bronchial hyperresponsiveness (BHR) had PR of 2.47, 95% CI: 1.50-4.09; and confirmed asthma had PR of 2.65, 95% CI: 1.45-4.85. In addition, the overlap of asthma, rhinitis, and skin symptoms in a same subject was significantly more prevalent in the occupational sensitization group, 16.2% versus 4.9% in the common sensitization group. CONCLUSION AND CLINICAL RELEVANCE: Occupational sensitization is associated with allergic symptoms and respiratory diseases. SPT with occupational allergens along with other parameters may contribute to detection of risk for allergic and respiratory diseases associated with exposure to laboratory animals.

Detecting and modelling delayed density-dependence in abundance time series of a small mammal (Didelphis aurita).

We study the population size time series of a Neotropical small mammal with the intent of detecting and modelling population regulation processes generated by density-dependent factors and their possible delayed effects. The application of analysis tools based on principles of statistical generality are nowadays a common practice for describing these phenomena, but, in general, they are more capable of generating clear diagnosis rather than granting valuable modelling. For this reason, in our approach, we detect the principal temporal structures on the bases of different correlation measures, and from these results we build an ad-hoc minimalist autoregressive model that incorporates the main drivers of the dynamics. Surprisingly our model is capable of reproducing very well the time patterns of the empirical series and, for the first time, clearly outlines the importance of the time of attaining sexual maturity as a central temporal scale for the dynamics of this species. In fact, an important advantage of this analysis scheme is that all the model parameters are directly biologically interpretable and potentially measurable, allowing a consistency check between model outputs and independent measurements.

3D evaluation of maxillary arches in unilateral cleft lip and palate patients treated with nasoalveolar moulding vs. Hotz's plate.

To compare the three-dimensional changes occurring in the maxillary arch during the use of modified pre-surgical nasoalveolar moulding (PNAM) and Hotz's plate. A clinical trial including 32 children with unilateral cleft lip and palate (UCLP), 16 treated with Hotz's plate and 16 with PNAM, was performed. Impressions of the maxillary arches were taken: A. prior to pre-surgical orthopaedics, B. before cheiloplasty and C. after cheiloplasty. Models were digitised using a stereophotogrammetric instrument, and geodesic distances were calculated: anterior, canine and posterior widths of the arch, and lengths and cleft depths of the larger and shorter segments. The time and treatment effects were assessed by two-factor anova. A significant effect of treatment was found for cleft depth at the larger segment: children treated with Hotz's plate had significantly deeper cleft than children treated with PNAM. All distances significantly changed during time: the anterior and canine widths decreased, while the posterior width, the lengths and depths of the cleft segments increased. Significant treatment per time interactions was found. The anterior and canine widths reduced more with PNAM between time points A and B while Hotz's treatment was more effective between B and C. The shorter segment depth increased more between B and C with PNAM, and between A and B with Hotz's plate. During pre-surgical orthopaedics, therapy with PNAM obtained the best results in reducing the width at the anterior segment of the cleft. This treatment gave a lower increase in cleft depth than treatment with Hotz's plate.

Three-dimensional analysis of dentolabial relationships: effect of age and sex in healthy dentition.

Morphological changes in three-dimensional (3D) dentolabial relationships during ageing were assessed in healthy individuals. 38 subjects with healthy dentition were analysed. They were divided into a youthful group (21-34 years, mean 26 years, SD 4) and an older group (45-65 years, mean 53 years, SD 5). Stone labial and dental models were made, digitized and 3D virtual reproductions of dentolabial morphology were obtained. From the digital reconstructions, the relative positions of the labial commissure and of the maxillary dental clinical crowns in the vertical direction were obtained. Sex and age effects were compared using two-way analysis of variance. Lip position relative to the teeth was significantly different in youthful and older subjects (P<0.01). No statistically significant effects of sex in dentolabial relationship were demonstrated, but a sex×age effect was found in the anterior labial segments (P<0.05). The perioral soft tissues drop down in older subjects and the soft tissue descends on the entire labial arch. These differences may help the clinician when estimating, planning and evaluating surgical, orthodontic and prosthetic treatments.

Application of a computational model of vagus nerve stimulation.

OBJECTIVES: The most widely used and studied neurostimulation procedure for medically refractory epilepsy is vagus nerve stimulation (VNS) Therapy. The goal of this study was to develop a computational model for improved understanding of the anatomy and neurophysiology of the vagus nerve as it pertains to the principles of electrical stimulation, aiming to provide clinicians with a systematic and rational understanding of VNS Therapy. MATERIALS AND METHODS: Computational modeling allows the study of electrical stimulation of peripheral nerves. We used finite element electric field models of the vagus nerve with VNS Therapy electrodes to calculate the voltage field for several output currents and studied the effects of two programmable parameters (output current and pulse width) on optimal fiber activation. RESULTS: The mathematical models correlated well with strength-duration curves constructed from actual patient data. In addition, digital constructs of chronic versus acute implant models demonstrated that at a given pulse width and current combination, presence of a 110-µm fibrotic tissue can decrease fiber activation by 50%. Based on our findings, a range of output current settings between 0.75 and 1.75 mA with pulse width settings of 250 or 500 µs may result in optimal stimulation. CONCLUSIONS: The modeling illustrates how to achieve full or nearly full activation of the myelinated fibers of the vagus nerve through output current and pulse width settings. This knowledge will enable clinicians to apply these principles for optimal vagus nerve activation and proceed to adjust duty cycle and frequency to achieve effectiveness.

Three-dimensional analysis of labial morphology: effect of sex and age.

Morphological changes in the lips during ageing, including labial volume, area and thickness were assessed in healthy individuals. 40 healthy volunteers (20 men and 20 women) were selected and divided into two groups according to age: 21-34 years ('youthful' group) and 45-65 years ('aged' group). Three-dimensional (3D) stone labial models were made, digitized, and 3D virtual reproductions obtained. Labial thickness, vermilion area, and volume of the upper and lower lips were measured from the digital reconstructions. The data were compared using three-way ANOVA. All data were significantly larger in men than in women (p<0.05), the lower lip was thicker than the upper lip (p<0.001). A significant effect of age for labial thickness and area were found (p<0.001 and p=0.014): the youthful group had higher values than the aged group. Upper to lower lip ratios were not significantly different between sexes or ages. Generally, young people have a larger lip area and thickness than aged ones and men had larger lips than women. The upper/lower lip ratios for area and volume were similar in the two genders.

Measurements of k0 and Q0 values for 64Zn(n,γ)65Zn and 68Zn(n,γ)69mZn reactions with covariance analysis.

The values of k(0) and Q(0) for (64)Zn(n,γ)(65)Zn and (68)Zn(n,γ)(69m)Zn reactions were determined experimentally. The irradiations were performed near the core of the IEA-R1 3.5MW nuclear research reactor of the Nuclear and Energy Research Institute - IPEN-CNEN/SP, in São Paulo, Brazil. The results for the neutron field parameters f and α were 49.7(19) and -1.1(31)×10(-3), respectively. The resulting values of k(0) and Q(0) for (64)Zn(n,γ)(65)Zn reaction were 5.63(8)×10(-3) and 1.69(6), respectively, and the corresponding values for (68)Zn(n,γ)(69m)Zn reaction were 4.00(6)×10(-4) and 2.34(4), respectively. These results were compared with the literature.

EMG analysis of trapezius and masticatory muscles: experimental protocol and data reproducibility.

We aimed to define a standardised protocol for the electromyographic evaluation of trapezius muscle in dentistry and to assess its within- and between-session repeatability. Surface electromyography of trapezius, masseter and temporal muscles was performed in 40 healthy subjects aged 20-35 years during shoulder elevation, and maximum teeth clenching with and without cotton rolls. Two repetitions were made both within (same electrodes) and between sessions (different electrodes). Maximum voluntary clench on cotton rolls was used to standardise the potentials of the six analysed muscles with tooth contact; shoulder elevation was used to standardise the upper trapezius potentials. From the standardised electromyographic potentials, several indices (muscle symmetry; masticatory muscle torque and relative activity; total masticatory muscle activity; trapezius cervical load, percentage co-contraction of trapezius during teeth clenching) were computed; random (technical error of measurement) and systematic (Student's t-test, Analysis of Variance) errors were assessed. For all indices, no systematic errors were found between the two separate data collection sessions. Within session, limited (lower than 8%) technical errors of measurement were found for temporalis and masseter symmetry, torque and activity indices, and the trapezius cervical load. Larger random errors were obtained for trapezius symmetry and total masticatory muscle activity (up to 20%). Between sessions, no significant differences were found for trapezius co-contraction. In conclusion, a protocol for the standardisation of trapezius muscle that may be used within dental clinical applications was defined, and the repeatability of masseter, temporalis and trapezius electromyographic recordings for serial assessments was assessed in healthy subjects.

Immediate effect of an elastomeric oral appliance on the neuromuscular coordination of masticatory muscles: a pilot study in healthy subjects.

To compare the electromyographic characteristics of masticatory muscles with and without a new elastomeric oral device proposed for masticatory muscle training, 10 healthy subjects aged 23 to 32 were examined. Surface electromyography of masseter and temporal muscles was performed during maximum teeth clenching without and with the device and during unilateral chewing with either gum or the device. During clenching, a significant increment of the overall muscular activity was promoted by the occlusal device in comparison with the intercuspal teeth clenching (P=0·05). Muscular standardised activity during device chewing was significantly higher than that during gum chewing (P=0·005), and it was more evenly distributed between working and balancing sides (P=0·023 right side, P=0·039 left side), and between masseter and temporal muscles (right side test, P=0·014). No significant differences were found for the global neuromuscular co-ordination, the masticatory symmetry and the chewing frequency. Clenching and chewing with the analysed occlusal prostheses was performed with a relative increment of muscular activity. These findings may be the basis for the training effect proposed for this device.

Nasal base symmetry: a three dimensional anthropometric study.

AIM: The aim of this paper was to evaluate directional and fluctuating asymmetry, nostril and alar divergence in the nasal base of healthy young adults. To estimate nostril area and to investigate its relationships with cutaneous nasal area. METHODS: Three-dimensional plaster models of the nose of 20 young healthy white adults were obtained, digitized and mathematically reconstructed using Non Uniform Rational B-Splines (NURBS) curves. Linear distances (alar length, nostril axis length), angles (interalar angle, interaxial angle; angle between each nostril and alar axes), and surface areas (cutaneous nasal surface; right and left nostril area) were computed using NURBS-reconstructed models. RESULTS: The left side nasal structures were somewhat larger than the homologous right side ones (P<0.05). Nostril axis was approximately 60% of the corresponding alar length. Nostril area was approximately 3% of cutaneous nasal area. Alar length explained 31-36% of the individual variations in nostril axis length. Cutaneous nasal area explained 54-56% of nostril area, while the interalar angle explained 35% of the variations in interaxial angle. CONCLUSIONS: The method provided simple measurements of nasal base dimensions and asymmetry; some asymmetry was found also in healthy adults; only moderate relationships between nostril and alar dimensions and angles, as well as between nasal and nostril areas, were found, thus pointing to the necessity of detailed nostril assessments.

Intracellular crowding defines the mode and sequence of substrate uptake by Escherichia coli and constrains its metabolic activity.

The influence of the high intracellular concentration of macromolecules on cell physiology is increasingly appreciated, but its impact on system-level cellular functions remains poorly quantified. To assess its potential effect, here we develop a flux balance model of Escherichia coli cell metabolism that takes into account a systems-level constraint for the concentration of enzymes catalyzing the various metabolic reactions in the crowded cytoplasm. We demonstrate that the model's predictions for the relative maximum growth rate of wild-type and mutant E. coli cells in single substrate-limited media, and the sequence and mode of substrate uptake and utilization from a complex medium are in good agreement with subsequent experimental observations. These results suggest that molecular crowding represents a bound on the achievable functional states of a metabolic network, and they indicate that models incorporating this constraint can systematically identify alterations in cellular metabolism activated in response to environmental change.

Separating internal and external dynamics of complex systems.

The observable behavior of a complex system reflects the mechanisms governing the internal interactions between the system's components and the effect of external perturbations. Here we show that by capturing the simultaneous activity of several of the system's components we can separate the internal dynamics from the external fluctuations. The method allows us to systematically determine the origin of fluctuations in various real systems, finding that while the Internet and the computer chip have robust internal dynamics, highway and Web traffic are driven by external demand. As multichannel measurements are becoming the norm in most fields, the method could help uncover the collective dynamics of a wide array of complex systems.

Fluctuations in network dynamics.

Most complex networks serve as conduits for various dynamical processes, ranging from mass transfer by chemical reactions in the cell to packet transfer on the Internet. We collected data on the time dependent activity of five natural and technological networks, finding that for each the coupling of the flux fluctuations with the total flux on individual nodes obeys a unique scaling law. We show that the observed scaling can explain the competition between the system's internal collective dynamics and changes in the external environment, allowing us to predict the relevant scaling exponents.

When might hemispheric favouring of epileptiform discharges begin?

PURPOSE: EEG studies based on adult populations report interictal epileptiform discharges (EDS) favour the left hemisphere. It is not clear when favouring becomes apparent as similar paediatric studies have not been performed. METHODS: The authors reviewed 1,579 paediatric EEG interpretations for evidence of hemispheric favouring of focal epileptiform discharges. Analysis focused on first-time EEG results. RESULTS: Right hemispheric favouring of interictal epileptiform discharges occurs in childhood, it remits around 5 years of age whereupon left-sided favouring occurs more frequently (P=0.004, Fisher's Exact). CONCLUSION: Hemispheric vulnerabilities to interictal focal epileptiform activity may display discrete age-related favouring. These findings are discussed in context of normal hemispheric maturation.

Serum IgE level in malnutrition.

UNLABELLED: Infections and malnutrition remain the main causes of infant mortality in developing countries. In protein-calorie malnutrition, immunologic responses are affected, which often facilitates infections. However, the presence of asthma and allergic rhinitis are not commonly recognized in malnourished individuals. The aim of this study was to evaluate serum IgE values in children with primary moderate protein-calorie malnutrition. METHODS: The level of IgE in peripheral blood of 18 children between 2 and 4 old with moderate protein-calorie malnutrition and without associated parasitic infestation was compared with that of 15 well nourished children of similar age. IgE serum levels were measured by an immunoenzymatic method. RESULTS: The median level of serum IgE in malnourished children was 69.30 ng/ml while the control group showed a mean level of 95.97 ng/ml. This difference was significant (p < 0.01). CONCLUSION: Malnourished children show decreased serum IgE levels. This might be one of the adaptive mechanisms of malnutrition employed in an attempt to use energy and protein reserves for growth and other functions. Our results are coherent with the decrease in IgE mediated reactions in malnourished patients.

Atopic dermatitis with mononuclear phagocytic activity deficiency.

Five patients with atopic dermatitis, three males and two females, aged 2 to 17 years, had positive reactions to air allergens (Dermatophagoides pteronyssinus and/or farinae). All the patients suffered from severe recurrent dermatophytosis that responded poorly to antifungal treatment. The results of immunologic evaluation by laboratory tests were normal, except for a decrease in the ingestion phase by mononuclear phagocytes. After diagnosis of immunodeficiency, ketoconazole shampoo was used prophylactically and at the very first signs of recurrence of dermatophytosis, systemic antifungal treatment was started, without concurrent use of macrolides and with monitoring of hepatic function. The fungal infections responded well to this treatment and the patients' quality of life markedly improved.

Shortest paths on systems with power-law distributed long-range connections.

We discuss shortest-path lengths l(r) on periodic rings of size L supplemented with an average of pL randomly located long-range links whose lengths are distributed according to P(l) approximately l(-mu). Using rescaling arguments and numerical simulation on systems of up to 10(7) sites, we show that a characteristic length xi exists such that l(r) approximately r for r>xi. For small p we find that the shortest-path length satisfies the scaling relation l(r,mu,p)/xi=f(mu,r/xi). Three regions with different asymptotic behaviors are found, respectively: (a) mu>2 where theta(s)=1, (b) 1

Temporal lobectomy in early childhood: the need for long-term follow-up.

We retrospectively identified 15 children ages 12 years and under with anticonvulsant resistant epilepsy who underwent a temporal lobectomy at Children's Hospital, Boston, between 1978 and 1993. Our aim was to study the long-term seizure outcome. Data pertaining to preoperative evaluation, electroencephalography (EEG), neuroimaging, surgery, seizure outcome, and postoperative complications were reviewed. Only patients followed for more than 12 months were included. The average duration of follow-up was 57 months. At the last visit, 47% (7 of 15) of the children were seizure free or only had auras: another 33% (5 of 15) had > 90% reduction in seizure frequency. Three patients had < 90% seizure reduction. Four cases were initially seizure free but had subsequent recurrence between 11 and 28 months after the epilepsy surgery. Factors associated with a good outcome include exclusively focal EEG discharges or an imaging suggestive of a low-grade tumor; factors associated with a poor outcome include generalized EEG discharges and a normal magnetic resonance image. Temporal lobectomy is useful in the treatment of early childhood drug-resistant partial epilepsy, but long-term follow-up is necessary as late seizure recurrence may occur up to 28 months after surgery.