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The aims of this study were to: i) investigate the repeatability and representativeness of personal radio frequency-electromagnetic fields (RF-EMFs) exposure measurements, across different microenvironments, ii) perform simultaneous evaluations of personal RF-EMF exposures for the whole body and the head, iii) validate the data obtained with a head-worn personal distributed exposimeter (PDE) against those obtained with an on-body worn personal exposimeter (PEM). Data on personal and head RF-EMF exposures were collected by performing measurements across 15 microenvironments in Melbourne, Australia. A body-worn PEM and a head-worn PDE were used for measuring body and head exposures, respectively. The summary statistics obtained for total RF-EMF exposure showed a high representativeness (r 2 > 0.66 for two paths in the same area) and a high repeatability over time (r 2 > 0.87 for repetitions of the same path). The median head exposure in the 900 MHz downlink band ranged between 0.06 V/m and 0.31 V/m. The results obtained during simultaneous measurements using the two devices showed high correlations (0.42 < r 2 < 0.94). The highest mean total RF-EMF exposure was measured in Melbourne's central business district (0.89 V/m), whereas the lowest mean total exposure was measured in a suburban residential area (0.05 V/m). This study shows that personal RF-EMF microenvironmental measurements in multiple microenvironments have high representativeness and repeatability over time. The personal RF-EMF exposure levels (i.e. body and head exposures) demonstrated moderate to high correlations. [ABSTRACT FROM AUTHOR]

This study investigates wireless power transfer for deep in-body receivers, determining the optimal frequency, power budget, and design for the transmitter and receiver. In particular, the focus is on small, in-body receivers at large depths up to 20 cm for obese patients. This enables long-term monitoring of the gastrointestinal tract for all body types. Numerical simulations are used to investigate power transfer and losses as a function of frequency and to find the optimal design at the selected frequency for an obese body model. From all ISM-frequencies in the investigated range (1 kHz–10 GHz), the value of 13.56 MHz yields the best performance. This optimum corresponds to the transition from dominant copper losses in conductors to dominant losses in conductive tissue. At this frequency, a transmitting and receiving coil are designed consisting of 12 and 23 windings, respectively. With a power transfer efficiency of 2.70 × 10 − 5 , 18 µW can be received for an input power of 0.68 W while still satisfying exposure guidelines. The power transfer is validated by measurements. For the first time, efficiency values and the power budget are reported for WPT through 20 cm of tissue to mm sized receivers. Compared to WPT at higher frequencies, as commonly used for small receivers, the proposed system is more suitable for WPT to large depths in-body and comes with the advantage that no focusing is required, which can accommodate multiple receivers and uncertainty about receiver location more easily. The received power allows long-term sensing in the gastrointestinal tract by, e.g., temperature, pressure, and pH sensors, motility sensing, or even gastric stimulation. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to find the reasons for referral and their correlation with age, gender, field of view, and resolution for all patients under the age of 18 who underwent a cone-beam computed tomography (CBCT) scan between 1 May 2010 and 1 May 2012 in the dental out-patient clinic of the University Hospital Ghent. Material and methods: From the local CBCT database, 79 pediatric patients gave their consent. Subsequently age, gender, reason for referral, external or internal referral, field of view (FOV), and resolution data were collected. Descriptive and comparative statistical analysis was performed. Results: There seemed to be a correlation between orthodontic referrals and female patients. The majority of patients referred for trauma follow-up were 12 years and older. Fourteen percent of referrals were for dento-alveolar trauma, 18 % for other dento-alveolar reasons, 4 % for developing dentition-generalized, 36 % for developing dentition-localized, 10 % for endodontics, 1 % for periodontics, 16 % for surgical applications, and 1 % was for the visualization of the TMJ. Eighty percent of the CBCTs were taken at a FOV 50 × 55 mm. Larger FOV was used for surgical planning or follow-up reasons. The majority of the CBCTs was taken at a resolution of 200 μm, while a resolution of 150 μm was used for endodontic issues. From these results, a classification system for referral was developed. Conclusions: From the present study, it can be concluded that a referral pattern could be detected which was correlated with gender, age group, FOV, and resolution. These results can help practitioners make the decision to refer for CBCT when extra three dimensional imaging is expected to have a benefit in therapeutic value for a pediatric or adolescent patient. Clinical relevance: This study can guide dental professionals referring pediatric and adolescent patients for CBCT. [ABSTRACT FROM AUTHOR]

Aim The aim of this study was to analyze whether any correlation existed between Flemish dental practitioner's educational background and their perceptions of their knowledge regarding emergency treatment for crown fractures and their actual expertise. Methods A questionnaire was distributed among 336 dental practitioners at six different locations in the country and completed prior to a lecture on dental traumatology. The response rate was 100%. The questionnaire consisted of three parts: the first part enquired about personal background, the second part requested a self-assessment of the practitioner's dental trauma education and treatment experience, and the third part tested the knowledge of the practitioner by asking for responses to different options for emergency treatment for dental trauma. Results Nearly 63% of the participants had more than 20 years of experience. Satisfaction about adequacy in basic education in dental traumatology was significantly related to the years as graduation to older graduates being less satisfied. This observation was not related to the additional education taken. Most frequently, uncomplicated crown fractures (42%) were seen more frequently than severe injuries. Concerning knowledge, a high result (67%) of incorrect answers was given for the treatment for injured immature permanent incisors. However, a high correlation was found between good knowledge of treatment and young professionals who graduated <10 years ago. Referring dental injuries for treatment was correlated with increasing level of difficulty. In the permanent dentition, however, complicated crown fractures ( CCF) in immature teeth were not referred in many (66%) cases. Conclusion It was observed that the knowledge of Flemish dental practitioners regarding emergency treatment for CCF is insufficient especially for the management of immature incisors. [ABSTRACT FROM AUTHOR]

Introduction: Dentin hypersensitivity (DHS) is a problematic clinical entity that may become an increasing clinical problem for dentists to treat as a consequence of patients retaining their teeth throughout life and improved oral hygiene practices. Objectives: The aim of this review was to develop a decision tree for the management of exposed cervical dentin (ECD) and DHS. Material and methods: A brief PUBMED literature search was performed on dentin hypersensitivity using 'MeSH' terms, 'review', and 'management'. In addition, some websites and local guidelines were screened. Results: From this review, it became clear that all dentate patients should routinely be screened for ECD and DHS. In this respect, underdiagnosis of the condition will be avoided and the preventive management can be initiated early. Conclusion: A decision tree process and a flowchart for daily practice were designed which should be started up as soon as a patient present with ECD or suffers from DHS. This approach takes into account the possible improved quality of life of the patient and is further based on a hierarchy of treatment options. In this respect, active management of DHS will usually involve a combination of at-home and in-office therapies. Starting with the use of desensitizing toothpastes is strongly recommended. [ABSTRACT FROM AUTHOR]

To estimate the exposure around a base station, the frequency-selective electromagnetic field measurement with a spectrum analyzer and antenna is the most appropriate method. In this paper, a theoretical model for the wideband code division multiaccess signal, which is measured by a spectrum analyzer, is extended to the measurement of the signal used in the universal mobile telecommunications system (UMTS), where the transmitted signal is subject to power control. The developed model is successfully validated by measurements. It is shown that the presence of power control has important implications on the achievable accuracy of the measurements. Based on the developed model, the optimal settings of the spectrum analyzer are proposed for the exposure assessment around UMTS base stations. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The aim of the present study was to investigate the relative curing degree at a depth of 2mm of several polyacid-modified composites (PAM-Cs) as a function of shade. Methods: The Knoop hardness of the irradiated top and non-irradiated bottom surfaces of 2mm thick samples of the PAM-Cs Hytac, F2000, Glasiosite, Dyract, Dyract AP, and Compoglass F and of the resin composites Z100, Herculite Enamel XRV, and Durafill VS, were determined for shades A2 and A4. Results: The top and bottom hardness of F2000 and Glasiosite ranged between that of the two composites Herculite and Z100. Compoglass, Dyract and Dyract AP had a lower top and bottom hardness than the hybrid composites, but higher than that of the microfilled composite Durafill. The top hardness of Hytac compared with that of the first group, whereas the bottom hardness compared with the second group. The bottom-to-top KHN ratio reflecting the relative curing degree at a depth of 2mm was less than 80% for the two shades of Hytac and Compoglass as well as for the A4 shade of Dyract AP and Herculite. Significance: A hard top surface of a PAM-C is not an indication of adequate in depth polymerization. Shade A2 results in significantly greater values for the curing degree compared to shade A4, the effect depending quantitatively on the formulation of the material. Some formulations of PAM-C do not reach an adequate curing degree at a depth of 2mm so that it is recommended to apply the incremental technique even in box-only cavities with layers of maximum 2mm. [Copyright &y& Elsevier]

Frequency-selective measurements with a spectrum analyzer are the most obvious means to accurately measure the power of a communication signal. In this paper, models for the spectrum analyzer and for the wideband code division multiaccess (WCDMA) signal are described. Based on these models, the analytic expressions for the probability density function (PDF) of the displayed signal have been derived for the different detection modes [sample, root mean square (rms) and positive-peak detection] of the spectrum analyzer. Based on these theoretical considerations, the dependence of the mean and standard deviation of the measured signal on the observation time of the detector has been examined, which showed a good agreement with the simulated results. [ABSTRACT FROM AUTHOR]

A comparison between the safety distances of a base station antenna using electromagnetic field and the specific absorption rate (SAR) assessment is made. The input power in the antenna is determined such that the electromagnetic fields and the SAR equal the reference levels and the basic restrictions, respectively, at a certain distance. Up to about 10 W the localized SAR delivers the largest safety distances when the electric field averaged in a volume is considered. This means that from 10 W and up the SAR does not need to be determined to obtain the largest safety distances. Safety distances based on the SAR will be smaller than those obtained from the electromagnetic fields when the maximum field value in a plane is considered. [ABSTRACT FROM AUTHOR]

Abstract: Although saliva or oral fluid “lacks the drama of blood, the sincerity of sweat and the emotional appeal of tears”, quoting Mandel in 1990 [I.D. Mandel, The diagnostic uses of saliva, J. Oral Pathol. Med. 19 (1990) 119–125], it is now meeting the demand for inexpensive, non-invasive and easy-to-use diagnostic aids for oral and systemic diseases, drug monitoring and detection of illicit use of drugs of abuse, including alcohol. As the salivary secretion is a reflex response controlled by both parasympathetic and sympathetic secretomotor nerves, it can be influenced by several stimuli. Moreover, patients taking medication which influences either the central nervous system or the peripheral nervous system, or medication which mimic the latter as a side effect, will have an altered salivary composition and salivary volume. Patients suffering from certain systemic diseases may present the same salivary alterations. The circadian rhythm determines both the volume of saliva that will and can be secreted and the salivary electrolyte concentrations. Dietary influences and the patient''s age also have an impact on composition and volume of saliva. The latter implies a wide variation in composition both inter- and intra-individually. Sampling must therefore be performed under standardized conditions. The greatest advantage, when compared to blood sample collection, is that saliva is readily accessible and collectible. Consequently, it can be used in clinically difficult situations, such as in children, handicapped and anxious patients, where blood sampling could be a difficult act to perform. [Copyright &y& Elsevier]

In this paper, an accurate method is developed to model dipole antennas In free-space or near an infinite perfectly electrical conducting plate. The magnetic field integral equation Is implemented and point-matching Is used to construct the interaction matrix. The edges of the cylinder, which can cause numerical instabilities in the simulated current distribution, are getting a special treatment by choosing a specific set of basis functions. The excitation is modeled based on the equivalence principle and leads to the application of a magnetic surface current over the gap region. The exact kernel of the integral equation is applied and all possible current components are taken into account. When the antenna Is close to a conducting plate, a strong modification of the surface current distribution is observed. It Is demonstrated that for these configurations, the Incorporation of the circumferential component of the surface current distribution is needed. At larger distances, the circumferential surface current can be neglected in the total distribution. The only approximation (or rather assumption) we made is that we impose a longitudinal directed electrical field over the boundary of the gap region. The results are verified experimentally. [ABSTRACT FROM AUTHOR]

The Ehlers–Danlos syndromes (EDS) comprise a heterogenous group of heritable disorders of connective tissue, characterized by joint hypermobility, skin hyperextensibility and tissue fragility. Most EDS types are caused by mutations in genes encoding different types of collagen or enzymes, essential for normal processing of collagen.Oral health was assessed in 31 subjects with EDS (16 with hypermobility EDS, nine with classical EDS and six with vascular EDS), including signs and symptoms of temporomandibular disorders (TMD), alterations of dental hard tissues, oral mucosa and periodontium, and was compared with matched controls.All EDS subjects were symptomatic for TMD and reported recurrent temporomandibular joint (TMJ) dislocations. Abnormal pulp shape (13%) and pulp calcification (78%) were observed in subjects affected with classical EDS. Caries experience was higher in EDS compared with controls and was related to poor oral hygiene, influenced by increased mucosal fragility and restraint of (wrist) joint mobility. The overall periodontal status in EDS was poor, with 62% of EDS subjects presenting high periodontal treatment needs (community periodontal index for treatment need, CPITN = II).Oral health may be severely compromised in EDS as a result of specific alterations of collagen in orofacial structures. When considering dental treatment in EDS, a number of tissue responses (mucosa, periodontium, pulp) and precautions (TMJ dislocation) should be anticipated.J Oral Pathol Med(2005)34: 298–307 [ABSTRACT FROM AUTHOR]

Summary: Objectives: This study investigates the effect of a neutral citrate solution on the fluoride release of 10 acid–base setting glass ionomer cements during 140 days at 37°C. Methods: Five disks of 10 acid–base setting restorative glass ionomers were prepared according to the manufacturer''s instructions. These specimens were immersed individually in 25ml of a 0.01mol/l citrate solution with pH=7. Over 140 days, the solutions were regularly renewed and the fluoride concentration eluted during each period was determined with a combined fluoride ion selective electrode. Results: The cumulative fluoride release was the result of an initial high release that ceased after some time and a long-term of low fluoride release. The long-term fluoride release was higher in neutral citrate solution than in water. For some formulations the short-term fluoride release also was higher in neutral citrate solution than in water suggesting that the polysalt matrix composition could be important in this respect. Significance: The fluoride release process is due not only to a loss of relatively loosely bound fluoride in the cement matrix, but also to the release of strongly bounded fluoride inducing a long-term fluoride release. The effect of citrate on the fluoride release process may increase depending on the acid (polyacrylic acid versus copolymers of polyacrylic acid) used for the polysalt formation in the hardening cement. Depending on the competition between the polyacrylate anion and the citrate anion for the metal cation extraction the fluoride release process may be retarded. [Copyright &y& Elsevier]

The use of frequency-selective measurements for the assessment of the worst-case exposure to electromagnetic fields radiated by GSM base stations is widely accepted to check the compliance with the existing regulations when multiple frequency sources are present. In this paper, the influence of different settings of the spectrum analyzer (resolution bandwidth, sweep rate, and detector) on the accuracy of power measurements has been studied with simulations by using a simple model for the spectrum analyzer and the global system for mobile communications (GSM) signal. The effect of adjacent frequency channels, time modulated signals, and down link power control have been investigated. Based on the obtained simulation results, optimal spectrum analyzer settings have been proposed for the exposure assessment around GSM base stations. As a final result, the accuracy of the proposed optimal settings for the spectrum analyzer has been determined. [ABSTRACT FROM AUTHOR]

In this paper, we present an improved method to determine the antenna factor of three antennas. Instead of using a reflecting ground plane we use absorbers. Destructive interference between the direct beam and the residual reflected beam from the absorbers is avoided by splitting the measured frequency range in bands and changing the distance between the two antennas depending on the frequency band. Furthermore, this method is applicable for both E- and H-field probes. Our method has also the advantage of being low-cost: The method does not need to be performed in an anechoic chamber to obtain high accuracy. To take the residual reflections of the environment into account, we perform a de-embedding procedure. We have developed two de-embedding methods. [ABSTRACT FROM AUTHOR]

In this paper, the influence of the measurement probe on the evaluation of the far and near field of an electromagnetic source is characterized. While measuring, the electromagnetic field will be disturbed by the measurement probes themselves. Therefore, not the true, free-space field but the disturbed field will be measured. The disturbance can not be fully taken into account by the calibration, especially in the near field. It is found that in the near field, these disturbances are much higher than in the far field for a large sensitive measurement probe. This paper will show that when the disturbance must be limited to a predefined value (e.g., 5%), a suitable measurement probe with maximum sensitivity can be selected. The characterization was performed using a numerical electromagnetic computational program. [ABSTRACT FROM AUTHOR]

The aim of the present study was to assess indicators shown to be associated with the prevalence of caries in the primary dentition of 7-year-old Flemish schoolchildren. Cross-sectional first year data of the longitudinal Signal-Tandmobiel® survey were analysed (n=4468). Gender, age, oral hygiene habits, use of fluorides, dietary habits, geographical factors and parental modelling were the considered predictors. From the multiple logistic regression analysis, including schools as a random effect, and after adjusting for the confounding variables-educational system and province (stratification variables}, gender and age-it became clear that the following risk indicators remained significant (at 5% level) for the presence of caries: frequency of toothbrushing (P=0.05) with an OR 1.24 for brushing less than once a day, age at start of brushing (P<0.001) with an OR=1.22 for a delay of 1 year, regular use of fluoride supplements (P<0.001) with an OR=1.54 for no use, daily use of sugar-containing drinks between meals (P<0.001) with an OR=1.38, and number of between-meals snacks (P=0.012) with an OR=1.22 for using more than 2 between-meal snacks. There was a significant difference (P<0.05) in caries experience determined by the geographical spread, with an explicit trend of caries declining from the east to the west. In a model with an ordinal response outcome, the daily use of sugar-containing drinks between meals had a more pronounced effect when caries levels were high. From this study it became obvious that, in Flemish children, an early start of brushing and a brushing frequency of at least once a day need to be encouraged, while the use of sugar-containing drinks and snacks between meals needs to be restricted to a maximum of 2 per day. Geographical differences need to be investigated in more detail. [ABSTRACT FROM AUTHOR]

Examines the electrical behavior of decoupling capacitors embedded in multilayered printed circuit boards. Optimal performing types of modules or board assemblies; Demand for the increased circuit density; Physical configuration of the interconnections and discontinuities in the network.

Presents test methods for the characterization of shielding of board-to-backplane and board-to-cable connectors used in telecommunication and computer systems. Definition of the quantities that describe the shielding performance; Relative shielding effectiveness of a shielded connector.

Examines the effects of the position of the averaging volume on the averaged specific absorption rate (SAR) values at the typical European cellular telephone frequencies around 900 and 1800 megahertz. Comparison of averaging procedure for SAR distributions; Variations in criteria for averaging procedures.

As part of a larger epidemiological survey of a stratified sample of 12-year-old handicapped children in Flanders, Belgium, the present study describes gingival health, gingival hypertrophy, oral cleanliness and the presence of calculus. Statistical analysis was performed with motor skills, brushing help, the use of chemical agents, the use of anti-epilectic drugs, the knowledge of parents and educators (or caregivers) and their opinion of the oral hygiene of their children/pupils as response variables. From this study, it became clear that mildly mentally retarded and learning-impaired children had significantly better manual dexterity skills than moderately and severely mentally retarded and physically impaired children. However, this was not reflected in improved oral hygiene. The use of chemical plaque controlling agents was found to be extremely low and, with the exception of children with gingival hyperplasia, the users of these agents did not have better oral hygiene. No difference was found between subtypes in the opinion of parents and educators on oral status. There was, however, a difference between their assessment and the clinical picture. It was concluded that there was a need for in-service training programmes in oral health care for educators as well as for parents. [ABSTRACT FROM AUTHOR]

In this presented study, we measured in situ the uplink duty cycles of a smartphone for 5G NR and 4G LTE for a total of six use cases covering voice, video, and data applications. The duty cycles were assessed at ten positions near a 4G and 5G base-station site in Belgium. For Twitch, VoLTE, and WhatsApp, the duty cycles ranged between 4% and 22% in time, both for 4G and 5G. For 5G NR, these duty cycles resulted in a higher UL-allotted time due to time division duplexing at the 3.7 GHz frequency band. Ping showed median duty cycles of 2% for 5G NR and 50% for 4G LTE. FTP upload and iPerf resulted in duty cycles close to 100%. [ABSTRACT FROM AUTHOR]

Studies the use of approximation of state functions in measurement-based transistor models. Representation of the state functions; Comparison between measurement and simulation; Implementation of the model in commercially available SPICE simulator; Modeling of current and charge functions and second-order effects.

Investigates the correlation between the impedance pattern for automatic noise-parameter determination and the accuracy of extracted parameters using a statistical approach. Selection criterion for the optimum admittance pattern; Simulations.

Presents a technique for the high-frequency circuit modeling of coupled conductor structures. Usefulness of the model for modeling structures with a varying signal/ground configuration; Reason two- and four-port models are easier to model; Examples of multiconductor structures; Accurate simulation of electrical properties of the conductors with the technique.

Mutations in the genes encoding fibrillin, an extracellular matrix protein involved in providing elastic properties to the connective tissues, may result in specific craniofacial and oral anomalies. A number of craniofacial (retrognathia, dolichocephaly, high palate) and dental (root deformity, pulp calcification) manifestations are considered pathognomic for the Marfan syndrome (MFS), a condition caused by congenital fibrillin-1 deficiency. Reports on similar features in congenital contractural arachnodactyly (CCA), caused by fibrillin-2 deficiency, support the hypothesis that fibrillin deficiency might result in a number of morphological anomalies by influencing tissue interaction during growth and development. Hence, clinical manifestations can be related to specific aspects of fibrillin deficiency pathogenesis, and may be adopted as diagnostic tools in the outlook for affected individuals. [ABSTRACT FROM AUTHOR]

Background: The general population is exposed to Radio-Frequency Electromagnetic Fields (RF-EMFs) used by telecommunication networks. Previous studies developed methods to assess this exposure. These methods will be inadequate to accurately assess exposure in 5G technologies or other wireless technologies using adaptive antennas. This is due to the fact that 5G NR (new radio) base stations will focus actively on connected users, resulting in a high spatio-temporal variations in the RF-EMFs. This increases the measurement uncertainty in personal measurements of RF-EMF exposure. Furthermore, a user's exposure from base stations will be dependent on the amount of data usage, adding a new component to the auto-induced exposure, which is often omitted in current studies.Goals: The objective of this paper is to develop a general study protocol for future personal RF-EMF exposure research adapted to 5G technologies. This protocol will include the assessment of auto-induced exposure of both a user's own devices and the networks' base stations.Method: This study draws from lessons learned from previous RF-EMF exposure research and current knowledge on 5G technologies, including studies simulating 5G NR base stations and measurements around 5G NR test sites.Results: To account for auto-induced exposure, an activity-based approach is introduced. In survey studies, an RF-EMF sensor is fixed on the participants' mobile device(s). Based on the measured power density, GPS data and movement and proximity sensors, different activities can be clustered and the exposure during each activity is evaluated. In microenvironmental measurements, a trained researcher performs measurements in predefined microenvironments with a mobile device equipped with the RF-EMF sensor. The mobile device is programmed to repeat a sequence of data transmission scenarios (different amounts of uplink and downlink data transmissions). Based on simulations, the amount of exposure induced in the body when the user device is at a certain location relative to the body, can be evaluated.Conclusion: Our protocol addresses the main challenges to personal exposure measurement introduced by 5G NR. A systematic method to evaluate a user's auto-induced exposure is introduced. [ABSTRACT FROM AUTHOR]

Objective: To explore the potential of ultrasonic modulation of plateau-potential generating subthalamic nucleus neurons (STN), by modeling their interaction with continuous and pulsed ultrasonic waves. Methods: A computational model for ultrasonic stimulation of the STN is created by combining the Otsuka-model with the bilayer sonophore model. The neuronal response to continuous and pulsed ultrasonic waves is computed in parallel for a range of frequencies, duty cycles, pulse repetition frequencies, and intensities. Results: Ultrasonic intensity in continuous-wave stimulation determines the firing pattern of the STN. Three observed spiking modes in order of increasing intensity are low frequency spiking, high frequency spiking with significant spike-frequency and spike-amplitude adaptation, and a silenced mode. Continuous-wave stimulation has little capability to manipulate the saturated spiking rate in the high frequency spiking mode. In contrast, STN firing rates induced by pulsed ultrasound insonication will saturate to the pulse repetition frequency with short latencies, for sufficiently large intensity and repetition frequency. Conclusion: Computational results show that the activity of plateau-potential generating STN can be modulated by selection of the stimulus parameters. Low intensities result in repetitive firing, while higher intensities silence the STN. Pulsed ultrasonic stimulation results in a shorter saturation latency and is able to modulate spiking rates. Significance: Stimulation or suppresion of the STN is important in the treatment of Parkinson's disease, e.g., in deep brain stimulation. This explorative study on ultrasonic modulation of the STN, could be a step in the direction of minimally invasive alternatives to conventional deep brain stimulation. [ABSTRACT FROM AUTHOR]

Abstract Energy-aware production scheduling is a promising way to adapt the factories' energy consumption behavior to the volatile electricity prices in the demand response initiative of smart grids. However, it may not be economical by simply scheduling production loads to the periods with lower electricity prices, as these periods often have higher labor wage, e.g., nights and weekends. Based on this gap, this paper proposes a many-objective integrated energy- and labor-aware flexible job shop scheduling model. Many objectives refer to the number of optimization objectives surpasses three (i.e., five objectives: makespan, total energy cost, total labor cost, maximal workload, and total workload), whereas the existing energy-aware production scheduling research is limited within three objectives. To enable energy awareness in the conventional production scheduling algorithms, a state-based shop floor wide energy model is proposed. To enable labor awareness, the number and type of human workers are matched to the scheduled production loads, with varying labor wage over shifts. As one of the most complex shop floor configurations, the partial flexible job shop further considers job recirculation and operation sequence-dependent machine setup times. The recently-proposed nondominated sorting genetic algorithm-III (NSGA-III) is tailored for this many-objective optimization problem (MaOP), including scheduling solution encoding and decoding, crossover, mutation, and solution evaluation using the energy- and labor-aware discrete-event simulation framework. Through numerical experiments under real-time pricing (RTP) and time-of-use pricing (ToUP), insights are statistically obtained on the relation among these five production objectives; the effectiveness and efficiency of NSGA-III in solving a MaOP are also demonstrated. This proposed scheduling method can be used to automated and enhance the decision making of factory managers in jointly allocating machine, human worker, and energy resources on the shop floor, such that the production cost is minimized even under time-varying electricity and labor prices. Highlights • Method to integrate both energy and labor awareness in conventional production scheduling models. • The most complex shop floor configuration is considered in this novel production scheduling model. • Many-objective optimization is investigated for the first time in the production scheduling domain. • The recently-proposed NSGA-III is tailored to solve this novel scheduling model. [ABSTRACT FROM AUTHOR]

Neuronal excitability is determined in a complex way by several interacting factors, such as membrane dynamics, fibre geometry, electrode configuration, myelin impedance, neuronal terminations[Formula: see text] This study aims to increase understanding in excitability, by investigating the impact of these factors on different models of myelinated and unmyelinated fibres (five well-known membrane models are combined with three electrostimulation models, that take into account the spatial structure of the neuron). Several excitability indices (rheobase, polarity ratio, bi/monophasic ratio, time constants[Formula: see text]) are calculated during extensive parameter sweeps, allowing us to obtain novel findings on how these factors interact, e.g. how the dependency of excitability indices on the fibre diameter and myelin impedance is influenced by the electrode location and membrane dynamics. It was found that excitability is profoundly impacted by the used membrane model and the location of the neuronal terminations. The approximation of infinite myelin impedance was investigated by two implementations of the spatially extended non-linear node model. The impact of this approximation on the time constant of strength-duration plots is significant, most importantly in the Frankenhaeuser-Huxley membrane model for large electrode-neuron separations. Finally, a multi-compartmental model for C-fibres is used to determine the impact of the absence of internodes on excitability. Graphical Abstract Electrostimulation models, obtained by combining five membrane models with three representations of the neuronal cable equation, are fed with electrode and stimulus input parameters. The dependency of neuronal excitability on the interaction of these input parameters is determined by deriving excitability indices from the spatiotemporal model response. The impact of the myelin impedance and the fibre diameter on neural excitability is also considered. [ABSTRACT FROM AUTHOR]

Stimulation of deep brain structures by transcranial magnetic stimulation (TMS) is a method for activating deep neurons in the brain and can be beneficial for the treatment of psychiatric and neurological disorders. To numerically investigate the possibility for deeper brain stimulation (electric fields reaching the hippocampus, the nucleus accumbens, and the cerebellum), combined TMS coils using the double-cone coil with the Halo coil (HDA) were modeled and investigated. Numerical simulations were performed using MIDA: a new multimodal imaging-based detailed anatomical model of the human head and neck. The 3D distributions of magnetic flux density and electric field were calculated. The percentage of volume of each tissue that is exposed to electric field amplitude equal or greater than 50% of the maximum amplitude of E in the cortex for each coil was calculated to quantify the electric field spread (V50). Results show that only the HDA coil can spread electric fields to the hippocampus, the nucleus accumbens, and the cerebellum with V50 equal to 0.04%, 1.21%, and 6.2%, respectively. [ABSTRACT FROM AUTHOR]

Tricalcium silicate cements (TSC) are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol), exposed surface area (ESA) and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter (n = 6/group). For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4). The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA (p < 0.05) while maximum calcium ion release was dependent on Vol of TSC (p < 0.05). Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution (p < 0.05). [ABSTRACT FROM AUTHOR]

Of particular interest within fifth generation (5G) cellular networks are the typical levels of radiofrequency (RF) electromagnetic fields (EMFs) emitted by 'small cells', low-power base stations, which are installed such that both workers and members of the general public can come in close proximity with them. In this study, RF-EMF measurements were performed near two 5G New Radio (NR) base stations, one with an Advanced Antenna System (AAS) capable of beamforming and the other a traditional microcell. At various positions near the base stations, with distances ranging between 0.5 m and 100 m, both the worst-case and time-averaged field levels under maximized downlink traffic load were assessed. Moreover, from these measurements, estimates were made of the typical exposures for various cases involving users and non-users. Comparison to the maximum permissible exposure limits issued by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) resulted in maximum exposure ratios of 0.15 (occupational, at 0.5 m) and 0.68 (general public, at 1.3 m). The exposure of non-users was potentially much lower, depending on the activity of other users serviced by the base station and its beamforming capabilities: 5 to 30 times lower in the case of an AAS base station compared to barely lower to 30 times lower for a traditional antenna. [ABSTRACT FROM AUTHOR]

Fixed wireless access (FWA) provides a solution to compete with fiber deployment while offering reduced costs by using the mmWave bands, including the unlicensed 60 GHz one. This paper evaluates the deployment of FWA networks in the 60 GHz band in realistic urban and rural environment in Belgium. We developed a network planning tool that includes novel backhaul based on the IEEE 802.11ay standard with multi-objective capabilities to maximise the user coverage, providing at least 1 Gbps of bit rate while minimising the required network infrastructure. We evaluate diverse serving node locations, called edge nodes (EN), and the impact of environmental factors such as rain and vegetation on the network design. Extensive simulation results show that defining a proper EN's location is essential to achieve viable user coverage higher than 95%, particularly in urban scenarios where street canyons affect propagation. Rural scenarios require nearly 75 ENs per km 2 while urban scenarios require four times (300 ENs per km 2 ) this infrastructure. Finally, vegetation can reduce the coverage by 3% or increment infrastructure up to 7%, while heavy rain can reduce coverage by 5% or increment infrastructure by 15%, depending on the node deployment strategy implemented. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor focusing on congenital contractual arachnodactyly.

This paper describes the exploration of the combined antenna–channel model for a horse hoof. An antenna of 25 mm × 40 mm is designed in the ISM 868 MHz band. During the characterization and design of the antenna, the dynamic and harsh environment of the horse hoof is taken into account throughout every step of the procedure because it is impossible to de-embed the antenna from its environment. The antenna and channel model are verified extensively by measurements in phantom and ex vivo. The antenna is verified to be robust against changes in the morphology of the horse's hoof up to 50%. The dynamic environment was captured by considering different soil types and air, and the design was verified to be resilient against changes herein. The antenna performs well within the targeted band, with a fractional bandwidth of 8% and a gain of −2 dBi. Furthermore, a path loss model was constructed for a typical barn environment, and the antenna reaches a range of 250 m in the studied environment based on the LoRa technology. This research is important for monitoring horse health. [ABSTRACT FROM AUTHOR]

An analysis of delay-Doppler characteristics in the presence of moving people is presented for short-range communication in an indoor environment. Channel-sounding measurements have been carried out at 3.6 GHz in a crowded university hall during several short and long breaks in-between courses. During three consecutive days, the measurements were repeated with different positions for the transmit and receive antennas. In this study, the behavior of the maximum Doppler shift and the Doppler spread was analyzed in the time-delay domain as a function of the occupation of the hall, the polarizations of the $2\times 2$ MIMO antennas, and their positions in the hall. The measurements reveal a clear distinction between the Doppler spread of the short and long breaks in the campaign, indicating a distinctive power distribution of their Doppler spectra. In addition, there is a significant contrast between the Doppler characteristics of the co- and cross-polarizations. Measurements at several positions reveal the importance of characterizing multipaths and show that the Doppler effect depends on the position of the antennas in the environment. In addition, this work also shows that the Doppler spectrum can be accurately modeled by a Cauchy distribution, allowing for the generation of parameters to describe Doppler characteristics. [ABSTRACT FROM AUTHOR]

A real-time indoor tracking system based on the Viterbi algorithm is developed. This Viterbi principle is used in combination with semantic data to improve the accuracy, that is, the environment of the object that is being tracked and a motion model. The starting point is a fingerprinting technique for which an advanced network planner is used to automatically construct the radio map, avoiding a time consuming measurement campaign. The developed algorithm was verified with simulations and with experiments in a building-wide testbed for sensor experiments, where a median accuracy below 2 m was obtained. Compared to a reference algorithm without Viterbi or semantic data, the results indicated a significant improvement: the mean accuracy and standard deviation improved by, respectively, 26.1% and 65.3%. Thereafter a sensitivity analysis was conducted to estimate the influence of node density, grid size, memory usage, and semantic data on the performance. [ABSTRACT FROM AUTHOR]

Age 18 years is considered as the age of majority by most countries. To ascertain the age of interest, both third molar development (TMD) and eruption (TME) staging scores are beneficial without needing multiple imaging modalities. This study aimed to assess the chronological course of TMD and TME in a Malay sub-adult population and evaluate predictions when specific stage(s) of TMD and TME have been attained that are pertinent to the age group of interest (<18 years or ≥18 years). A sample of 714 digital panoramic images for subjects stratified by age between 14.1 and 23.9 years was retrospectively collected. The techniques described by Gleiser and Hunt (modified by Kohler) and Olze were employed to stage TMD and TME, respectively. A binary logistic regression was performed to predict the 18-year threshold with staging score as predictors. Stages 4–6 (TMD) and A–B (TME) for males and stages 4 (TMD) and A (TME) for females were found to discriminate the <18-year group. For both genders, stages 9–10 (TMD) and D (TME) can be used as reference stages to estimate whether a subject is likely to be ≥18 years, with 94.74–100% and 85.88–96.38% correct predictions, respectively. Stages 4 (TMD) and A (TME) can also be used to identify juveniles (<18 years) with a high degree of correct predictions, 100%. The juvenility of an individual is easily anticipated by using the specific staging scores of both third molar variables (TMD and TME) without complex calculations. [ABSTRACT FROM AUTHOR]

Objectives To test the fracture strength of weakened bovine incisors endodontically treated with mineral trioxide aggregate ( MTA), calcium phosphate bone cement ( CPBC) or fibre reinforced composite ( FRC) posts, and to evaluate the fracture mode. Methods Weakened bovine incisors ( n = 75), standardized according to the dentinal wall thickness at the cervical area, were randomly assigned to one control group and three experimental groups. Unfilled teeth were assigned to group 1 ( n = 20) and served as control group. Group 2 ( n = 17) consisted of teeth filled with MTA. In group 3 ( n = 18), the incisors were filled with CPBC and in group 4 ( n = 20) with FRC posts. All specimens were subjected to load at a cross-head speed of 60 mm min−1 until fracture occurred. The initial ( IL) and final fracture ( FL) loads (N) were recorded, and the failure mode among the different groups was evaluated. Results anova showed a statistically significant difference in fracture load among the groups. Tukey's test revealed a significant difference for the IL between the control group and the experimental groups with exception of the MTA group. The FL was not significantly different among the experimental groups. A high percentage of favourable fractures was seen in the FRC and CPBC groups. Conclusion FRC posts and CPBC could be promising materials to strengthen non-vital structurally compromised teeth. [ABSTRACT FROM AUTHOR]

LTE-eMBMS systems efficiently deliver multicast/broadcast services using Layered Division Multiplexing (LDM) technology. In a two-layer LDM system, Layer 1, with higher power allocation delivers mobile services, and Layer 2 in a Single Frequency Network scheme provides local content. The challenge is to reduce the gap in the layers’ coverage areas caused by the use of different constellations, and SFN gain for Layer 2. Hence, the precision in the coverage area estimation is crucial for the successful planning and deployment, particularly regarding the SFN gain contribution in Layer 2. For this purpose, a real digital TV broadcasting SFN system was used as a model to design a method based on Machine Learning algorithms, aiming to enhance the coverage area precision for the Layer 2 in eMBMS. The method is able to estimate SFN gain value with a Mean Absolute Error (MAE) of 0.72 dB and certainty in positive or negative contribution in 93% of the cases. [ABSTRACT FROM AUTHOR]

Despite the recent advances in broadband penetration and accessibility, broadcasting networks continue to be the most efficient way for delivering media content to large areas independently of the user density. Nevertheless, a convergence of broadcasting services into the broadband networks is foreseen. In this context, Layered Division Multiplexing (LDM) allows the joint provision of unicast, multicast, and broadcast services in mobile cells infrastructure. Despite the success of LDM in broadcasting infrastructure, its practical application in Long Term Evolution networks providing Evolved Multimedia Broadcast Multicast Services (LTE eMBMS) and 5G-MBMS is more difficult. In this paper, we experimentally quantify the cell-interference and its impact on the network performance and Quality of Service. Our experiments reveal that the inter-cell interference margin for LTE eMBMS is about 3 dB higher compared to traditional LTE networks. If a layered architecture is incorporated this higher inter-cell interference would cause a reduction of approximately 19% of the Enhanced Layer (Lower Layer) coverage. [ABSTRACT FROM AUTHOR]

A framework is proposed for long-term vehicular channel simulation based on the vector time-frequency autoregressive (VTFAR) model for a sparse parametric description of nonstationary multivariate random processes. Based on vehicle-to-infrastructure tunnel measurements, we estimate the VTFAR model parameters and validate the model by comparing the parametric and non-parametric spectra of the measured channel in terms of the delay spread and stationarity time. In addition, the VTFAR model stability is investigated and an approximation for the correlated scattering channel is proposed. The experimental validation shows a good agreement with RMSE of only 0.01 for the delay spread and 0.4 for the stationarity time. This approach provides an efficient alternative for non-stationary channel simulation that is measurement-based and computationally inexpensive. [ABSTRACT FROM AUTHOR]

The main objective of this study was to identify the risk factors for the incidence of visible caries experience in a cohort of preschool children living in Flanders. Data were collected from 1,057 children; validated questionnaires on oral health-related behaviour were completed by parents at birth (2003-2004), at age 3 (2007) and 5 years (2009). At ages 3 and 5, the children were examined by trained dentists. Logistic regression analyses were performed with the following as outcome variables: visible caries experience at age 3 and increment in visible caries experience between ages 3 and 5. At ages 3 and 5, enamel and/or dentinal caries experience was observed in 22% and 41% of the cohort, respectively. The multivariable logistic regression analyses revealed that the presence of visible plaque accumulation on at least one primary tooth was a significant risk factor for visible caries experience at age 3 and for an increment in caries experience between ages 3 and 5. Children with previous caries experience at age 3 had significantly higher odds for new caries lesions at age 5. Presence of visible plaque and previous caries experience are confirmed as significant risk factors for visible caries experience in preschool children. Interventions aimed at caries prevention should focus on very young children and on the control of plaque accumulation. The presence of visible plaque accumulation as a screening tool to identify young children at risk for future caries experience shows high potential. [ABSTRACT FROM AUTHOR]

Endodontic treatment of immature teeth is often complicated because of flaring root canals and open apices for which apexification is needed. Long-term prognosis for these teeth is surprisingly low because of cervical root fractures occurring after an impact of weak forces. In this study, an experimental model was developed to determine the fracture resistance of immature teeth and to test the hypothesis that endodontic materials succeed in reinforcing them. Compact and hollow bone cylinders from bovine femurs were used as standardized samples. In order to evaluate the experimental model, fracture resistance in both groups was evaluated by determining the ultimate force to fracture (UFF) under diametral tensile stress. Analysis of variance (ANOVA) revealed a statistically significant difference between the mean values of UFF for both groups, independently of the sampling location or subject. In a following setting, the hypothesis that obturation with gutta percha (GP), mineral trioxide aggregate (MTA), or calcium phosphate bone cement (CPBC) reinforces the hollow bone samples was investigated. Obturation resulted in a significant reinforcement for all materials, but the degree of reinforcement depended on the material. The experimental model appeared to be suitable for in vitro investigation of reinforcement and fracture resistance in a standardized way. [ABSTRACT FROM AUTHOR]

Electromagnetic exposure of the general public due to large substations transforming voltages of 150 and 36 kV to 11 kV is investigated and safety distances for these substations have been determined. In total, 142 field measurements were executed for two substations: 91 measurements of the magnetic field and 51 measurements of the electric field. Measured momentary magnetic field values are within the range of 0.051 to 13.17 μT. The levels of the electric field are within the range of 0.095 to 270.0 V/m. The cumulative distribution function of the measured magnetic-field values has been determined, and it is shown that the fields excellently follow a lognormal distribution. The maximal magnetic and electric-field values for all the investigated substations are below 100 μT (values over a day and year) and 5 kV/m, respectively. When comparing the average exposure with the value of 0.4 μT, safety distances of maximally 8.1 m (average day) and 7.1 m (average year) are obtained. [ABSTRACT FROM AUTHOR]

Amethod for accurate determination of electromagnetic fields around the Worldwide Interoperability for Microwave Access (WiMAX) base stations (BSs) is developed in this paper. The influence of the characteristics of the WiMAX signal on the settings and parameters of the spectrum analyzer (SA) used for exposure assessment is investigated. Optimal settings of the SA are proposed, and the results obtained using simulations and measurements agree very well. A practical application in the neighborhood of a WiMAX BS is performed. The obtained electric field values correspond very well for the different settings and are compared with the reference levels for the general public and those for occupational exposure. The results of this paper can be used for practical measurement procedures of the exposure due to WiMAX signals. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the present study was to examine the prevalence and severity of caries experience in the primary dentition of preschool children and to assess the association of disease distribution with oral hygiene levels, reported oral health behaviours and socio-demographic factors. Methods: Study samples comprised 1250 3-year-old and 1283 5-year-old pre-school children from four distinct geographical areas in Flanders. Information on oral hygiene and dietary habits, oral health behaviours and socio-demographic variables was collected using questionnaires completed by the parents. Clinical examinations were performed using standardized criteria. Caries experience was recorded at the level of cavitation (d3 level). Simple as well as multivariable logistic regression analyses were performed in order to identify factors associated with prevalence and severity of caries experience. Results: Visible plaque was present in 31% of 3-year-olds and 37% of 5-year-olds. In 3-year-olds, 7% presented with caries experience while this was the case in 31% of 5-year-olds. Multivariable logistic regression revealed significant associations, in 3-year-olds, of caries experience with presence of dental plaque (OR = 7.93; 95% CI: 2.56–24.55) and reported consumption of sugared drinks at night (OR = 7.96; 95% CI: 1.57–40.51). In 5-year-olds, significant associations were seen with age (OR = 7.79; 95% CI: 2.38–25.43), gender (OR = 0.37 with 95% CI: 0.19–0.71 for girls), presence of visible dental plaque (OR = 3.36; 95% CI: 1.64–6.89) and reported habit of having sugar-containing drinks in between meals (OR = 2.60 with 95% CI: 1.16–5.84 and OR = 3.18 with 95% CI: 1.39–7.28, respectively for 1×/day and > 1×/day versus not every day). In 5-year-olds with caries experience (30.8% of total sample), the severity of disease was further analysed (d3mft between 1 and 4 versus d3mft 5 or higher). Multivariable analyses showed a significant association with gender [girls more likely to have higher disease levels; OR = 4.67 (95% CI: 1.65–13.21)] and with presence of plaque (OR = 3.91 with 95% CI: 1.23–12.42). Conclusions: Presence of visible plaque accumulation and reported consumption of sugared drinks were associated with prevalence of caries experience in Flemish preschool children. Severity of disease was associated with gender and with presence of plaque. Results underline the importance of plaque control and diet management from very young age on. [ABSTRACT FROM AUTHOR]

The influence of the characteristics of the WiMAX signal on the settings and parameters of the spectrum analyzer used for exposure assessment is investigated in this paper. Optimal settings of the spectrum analyzer are proposed for accurate determination of electromagnetic exposure around WiMAX base stations. [ABSTRACT FROM AUTHOR]

The Hybrid Fiber Coax (HFC) is a modern broadband access network, providing advanced interactive services such as Internet access, digital interactive television and cable telephony. The edge costs dominate the cost of launching new services, at the time of deployment (CapEx) as well as for maintenance (OpEx). Therefore next-generation edge devices aim at the convergence of these services and their platforms into a single multi-service infrastructure, thus sharing resources and bandwidth. The focus of this paper is on the HFC access network design for bandwidth-intensive TV services, bringing standard as well as switched broadcast technologies into play. Standard broadcast TV service deployments, offered through the Digital Video Broadcast (DVB) platform, require low installation costs, but the bandwidth consumption increases linearly with the number of available TV channels, even for very unpopular channels. Switched broadcast TV channels, offered on the (Euro-) DOCSIS platform together with other interactive unicast services such as Video on Demand, are only streamed to a node on the HFC access network if they are requested locally, thus limiting bandwidth consumption for less popular channels. We present an access network design tool, based on an analytical TV traffic model, minimizing the installation cost on the edge devices and study the influence of the most important traffic and content parameters. [ABSTRACT FROM AUTHOR]