Fatigue Resistance of Dissected Lower First Molars Restored with Direct Fiber-Reinforced Bridges-An In Vitro Pilot Study.

The aim of this research was to evaluate the mechanical impact of utilizing different fiber-reinforced composite (FRC) systems to reinforce inlay-retained bridges in dissected lower molars with different levels of periodontal support. A total of 24 lower first molars and 24 lower second premolars were included in this study. The distal canal of all molars received endodontic treatment. After root canal treatment, the teeth were dissected, and only the distal halves were kept. Standardized class II occluso-distal (OD) (premolars) and mesio-occlusal (MO) (dissected molars) cavities were prepared in all teeth, and premolar-molar units were created. The units were randomly distributed among four groups (n = six/group). With the aid of a transparent silicone index, direct inlay-retained composite bridges were fabricated. In Groups 1 and 2, both discontinuous (everX Flow) and continuous (everStick C&B) fibers were used for reinforcement, while in Groups 3 and 4, only discontinuous fibers (everX Flow) were used. The restored units were embedded in methacrylate resin, simulating either physiological periodontal conditions or furcation involvement. Subsequently, all units underwent fatigue survival testing in a cyclic loading machine until fracture, or a total of 40,000 cycles. Kaplan-Meyer survival analyses were conducted, followed by pairwise log-rank post hoc comparisons. Fracture patterns were evaluated visually and with scanning electron microscopy. In terms of survival, Group 2 performed significantly better than Groups 3 and 4 (p < 0.05), while there was no significant difference between the other groups. In the case of impaired periodontal support, a combination of both continuous and discontinuous short FRC systems increased the fatigue resistance of direct inlay-retained composite bridges compared to bridges that only contained short fibers. Such a difference was not found in the case of sound periodontal support between the two different bridges.

Wide-angle, monocular head tracking using passive markers.

BACKGROUND: Camera images can encode large amounts of visual information of an animal and its environment, enabling high fidelity 3D reconstruction of the animal and its environment using computer vision methods. Most systems, both markerless (e.g. deep learning based) and marker-based, require multiple cameras to track features across multiple points of view to enable such 3D reconstruction. However, such systems can be expensive and are challenging to set up in small animal research apparatuses. NEW METHODS: We present an open-source, marker-based system for tracking the head of a rodent for behavioral research that requires only a single camera with a potentially wide field of view. The system features a lightweight visual target and computer vision algorithms that together enable high-accuracy tracking of the six-degree-of-freedom position and orientation of the animal's head. The system, which only requires a single camera positioned above the behavioral arena, robustly reconstructs the pose over a wide range of head angles (360° in yaw, and approximately ± 120° in roll and pitch). RESULTS: Experiments with live animals demonstrate that the system can reliably identify rat head position and orientation. Evaluations using a commercial optical tracker device show that the system achieves accuracy that rivals commercial multi-camera systems. COMPARISON WITH EXISTING METHODS: Our solution significantly improves upon existing monocular marker-based tracking methods, both in accuracy and in allowable range of motion. CONCLUSIONS: The proposed system enables the study of complex behaviors by providing robust, fine-scale measurements of rodent head motions in a wide range of orientations.

Teleoperation and Visualization Interfaces for Remote Intervention in Space.

Approaches to robotic manufacturing, assembly, and servicing of in-space assets range from autonomous operation to direct teleoperation, with many forms of semi-autonomous teleoperation in between. Because most approaches require one or more human operators at some level, it is important to explore the control and visualization interfaces available to those operators, taking into account the challenges due to significant telemetry time delay. We consider one motivating application of remote teleoperation, which is ground-based control of a robot on-orbit for satellite servicing. This paper presents a model-based architecture that: 1) improves visualization and situation awareness, 2) enables more effective human/robot interaction and control, and 3) detects task failures based on anomalous sensor feedback. We illustrate elements of the architecture by drawing on 10 years of our research in this area. The paper further reports the results of several multi-user experiments to evaluate the model-based architecture, on ground-based test platforms, for satellite servicing tasks subject to round-trip communication latencies of several seconds. The most significant performance gains were obtained by enhancing the operators' situation awareness via improved visualization and by enabling them to precisely specify intended motion. In contrast, changes to the control interface, including model-mediated control or an immersive 3D environment, often reduced the reported task load but did not significantly improve task performance. Considering the challenges of fully autonomous intervention, we expect that some form of teleoperation will continue to be necessary for robotic in-situ servicing, assembly, and manufacturing tasks for the foreseeable future. We propose that effective teleoperation can be enabled by modeling the remote environment, providing operators with a fused view of the real environment and virtual model, and incorporating interfaces and control strategies that enable interactive planning, precise operation, and prompt detection of errors.

Effect of malnutrition and body composition on the quality of life of COPD patients.

BACKGROUND: Pathological alterations in nutritional status may develop in Chronic Obstructive Pulmonary Disease (COPD) patients through production of inflammatory cytokines and inadequate diet. OBJECTIVE: The aim of our study was to determine the correlation between nutritional status and quality of life of COPD patients. METHODS: We evaluated the nutritional status of COPD patients of Hungarian National Koranyi Institute for Pulmonology using the Malnutrition Universal Screening Tool (MUST) and bioelectrical impedance analysis (BIA) between January 1 and June 1, 2019. Lung function, physical fitness, and respiratory muscle strength were included in the assessment. RESULTS: Fifty patients (mean age was 66.3 ± 9.6 years) participated in our study. Mean body mass index (BMI) was 26.2 ± 6.1 kg/m2 and mean fat-free mass index (FFMI) was 16.8 ± 2.4 kg/m2. Overweight patients had better lung function values (FEV1ref%: 46.3 ± 15.2) than normal (FEV1ref%: 45.1 ± 20.9) and underweight patients (FEV1ref%: 43.8 ± 16.0). The Modified Medical Research Council Dyspnea Scale (mMRC) was significantly associated with various parameters; strongest correlation was found with FFMI (r = -0.537, P < 0.001), skeletal muscle mass index (SMMI) (r = -0.530, P < 0.001), and 6-minute walking distance (6MWD) (r = -0.481, P < 0.001). CONCLUSIONS: Our results indicate that malnourished COPD patients may have reduced lung function and lower quality of life compared to normal weight patients. Thus, our findings suggest that nutritional therapy be included in the treatment of COPD patients combined with nutritional risk screening and BIA during the follow-up.

Telerobotic Operation of Intensive Care Unit Ventilators.

Since the first reports of a novel coronavirus (SARS-CoV-2) in December 2019, over 33 million people have been infected worldwide and approximately 1 million people worldwide have died from the disease caused by this virus, COVID-19. In the United States alone, there have been approximately 7 million cases and over 200,000 deaths. This outbreak has placed an enormous strain on healthcare systems and workers. Severe cases require hospital care, and 8.5% of patients require mechanical ventilation in an intensive care unit (ICU). One major challenge is the necessity for clinical care personnel to don and doff cumbersome personal protective equipment (PPE) in order to enter an ICU unit to make simple adjustments to ventilator settings. Although future ventilators and other ICU equipment may be controllable remotely through computer networks, the enormous installed base of existing ventilators do not have this capability. This paper reports the development of a simple, low cost telerobotic system that permits adjustment of ventilator settings from outside the ICU. The system consists of a small Cartesian robot capable of operating a ventilator touch screen with camera vision control via a wirelessly connected tablet master device located outside the room. Engineering system tests demonstrated that the open-loop mechanical repeatability of the device was 7.5 mm, and that the average positioning error of the robotic finger under visual servoing control was 5.94 mm. Successful usability tests in a simulated ICU environment were carried out and are reported. In addition to enabling a significant reduction in PPE consumption, the prototype system has been shown in a preliminary evaluation to significantly reduce the total time required for a respiratory therapist to perform typical setting adjustments on a commercial ventilator, including donning and doffing PPE, from 271 to 109 s.

Health-related quality of life of COPD patients aged over 40 years.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is the fourth most frequent disease globally, and its worldwide prevalence is projected to increase in the following decades. Health-related quality of life (HRQOL) of COPD patients depends on multiple factors. OBJECTIVE: The aim of this study was to identify the most important risk factors affecting HRQOL of COPD patients and to measure how specific clinical parameters can predict HRQOL. METHODS: A questionnaire-based cross-sectional study combined with clinical data was conducted among patients diagnosed with COPD (n = 321, 52.6% females, mean age 66.4 ± 9.5) at the National Koranyi Institute for Pulmonology, Budapest in 2019-2020. The inclusion criteria were age ≥40 years and existing COPD. Multivariate linear regression analyses were conducted on three components of the COPD-specific Saint George's Respiratory Questionnaire (SGRQ-C) and on the physical (PCS) and mental component scales (MCS) of the 36-Item Short Form Health Survey (SF-36). Multiple linear regression analysis was performed to evaluate the effects of patient and disease characteristics on COPD Assessment Test (CAT) scores. RESULTS: We found that frequent exacerbations, multiple comorbidities and tobacco smoking were associated with worse HRQOL. Engaging in more frequent physical activity and better 6-minute walking distance results were associated with better HRQOL. CONCLUSIONS: Our results indicate that the complex therapy of COPD should focus not only on improving lung functions and preventing exacerbation, but also on treating comorbidities, encouraging increased physical activity, and supporting smoking cessation to assure better HRQOL for patients.

In Vitro Fracture Resistance of Adhesively Restored Molar Teeth with Different MOD Cavity Dimensions.

PURPOSE: Molar MOD (mesial-occlusal-distal) cavity preparation weakens relative cuspal stiffness by up to 63%, often resulting in cuspal fracture. This investigation inspects fracture resistance of MOD cavities restored using direct composite restoration. MATERIALS AND METHODS: 120 extracted, intact mandibular molars were selected. MOD cavities with different depth/wall thickness were prepared in 9 groups (n = 12): A: 3 mm/3.5 mm, B: 3 mm/2.5 mm, C: 3 mm/1.5 mm, D: 5 mm/3.5 mm, E: 5 mm/2.5 mm, F: 5 mm/1.5 mm, G: 7 mm/3.5 mm, H: 7 mm/2.5 mm, I: 7 mm/1.5 mm. Specimens with 7 mm deep cavities received root canal treatment. The teeth were restored with dental composite. Maximal fracture strength test was conducted. Intact natural teeth were used as control. For statistical analysis Kruskal-Wallis ANOVA with post-hoc pairwise comparisons was used (α = 0.05). RESULTS: Significant difference was indicated between the control and groups D, E, F, G, H, and I. No significant differences were found between the A, B, C groups and the control. Comparing the 5 and 7 mm cavity depth groups, there was no statistical difference between any of them. CONCLUSIONS: Within the limitations of this investigation, the following conclusions can be drawn regarding molar teeth with a MOD cavity: 3 mm or shallower cavities can be restored to the physiological fracture strength with direct composite restorations; 5 mm or deeper cavities cannot be restored to the physiological fracture strength with direct composite restorations. Cusp thickness does not significantly influence fracture strength in molar MOD cavities with a direct composite restoration.

Closed-Loop Control of Active Sensing Movements Regulates Sensory Slip.

Active sensing involves the production of motor signals for the purpose of acquiring sensory information [1-3]. The most common form of active sensing, found across animal taxa and behaviors, involves the generation of movements-e.g., whisking [4-6], touching [7, 8], sniffing [9, 10], and eye movements [11]. Active sensing movements profoundly affect the information carried by sensory feedback pathways [12-15] and are modulated by both top-down goals (e.g., measuring weight versus texture [1, 16]) and bottom-up stimuli (e.g., lights on or off [12]), but it remains unclear whether and how these movements are controlled in relation to the ongoing feedback they generate. To investigate the control of movements for active sensing, we created an experimental apparatus for freely swimming weakly electric fish, Eigenmannia virescens, that modulates the gain of reafferent feedback by adjusting the position of a refuge based on real-time videographic measurements of fish position. We discovered that fish robustly regulate sensory slip via closed-loop control of active sensing movements. Specifically, as fish performed the task of maintaining position inside the refuge [17-22], they dramatically up- or downregulated fore-aft active sensing movements in relation to a 4-fold change of experimentally modulated reafferent gain. These changes in swimming movements served to maintain a constant magnitude of sensory slip. The magnitude of sensory slip depended on the presence or absence of visual cues. These results indicate that fish use two controllers: one that controls the acquisition of information by regulating feedback from active sensing movements and another that maintains position in the refuge, a control structure that may be ubiquitous in animals [23, 24].

Representation of the inverse of a frame multiplier.

Certain mathematical objects appear in a lot of scientific disciplines, like physics, signal processing and, naturally, mathematics. In a general setting they can be described as frame multipliers, consisting of analysis, multiplication by a fixed sequence (called the symbol), and synthesis. In this paper we show a surprising result about the inverse of such operators, if any, as well as new results about a core concept of frame theory, dual frames. We show that for semi-normalized symbols, the inverse of any invertible frame multiplier can always be represented as a frame multiplier with the reciprocal symbol and dual frames of the given ones. Furthermore, one of those dual frames is uniquely determined and the other one can be arbitrarily chosen. We investigate sufficient conditions for the special case, when both dual frames can be chosen to be the canonical duals. In connection to the above, we show that the set of dual frames determines a frame uniquely. Furthermore, for a given frame, the union of all coefficients of its dual frames is dense in [Formula: see text]. We also introduce a class of frames (called pseudo-coherent frames), which includes Gabor frames and coherent frames, and investigate invertible pseudo-coherent frame multipliers, allowing a classification for frame-type operators for these frames. Finally, we give a numerical example for the invertibility of multipliers in the Gabor case.

Canonical forms of unconditionally convergent multipliers.

Multipliers are operators that combine (frame-like) analysis, a multiplication with a fixed sequence, called the symbol, and synthesis. They are very interesting mathematical objects that also have a lot of applications for example in acoustical signal processing. It is known that bounded symbols and Bessel sequences guarantee unconditional convergence. In this paper we investigate necessary and equivalent conditions for the unconditional convergence of multipliers. In particular, we show that, under mild conditions, unconditionally convergent multipliers can be transformed by shifting weights between symbol and sequence, into multipliers with symbol (1) and Bessel sequences (called multipliers in canonical form).

Theory, implementation and applications of nonstationary Gabor frames.

Signal analysis with classical Gabor frames leads to a fixed time-frequency resolution over the whole time-frequency plane. To overcome the limitations imposed by this rigidity, we propose an extension of Gabor theory that leads to the construction of frames with time-frequency resolution changing over time or frequency. We describe the construction of the resulting nonstationary Gabor frames and give the explicit formula for the canonical dual frame for a particular case, the painless case. We show that wavelet transforms, constant-Q transforms and more general filter banks may be modeled in the framework of nonstationary Gabor frames. Further, we present the results in the finite-dimensional case, which provides a method for implementing the above-mentioned transforms with perfect reconstruction. Finally, we elaborate on two applications of nonstationary Gabor frames in audio signal processing, namely a method for automatic adaptation to transients and an algorithm for an invertible constant-Q transform.

Travelling for teeth: characteristics and perspectives of dental care tourism in Hungary.

BACKGROUND AND AIM: Despite quite lively debates about dental care tourism, scientific studies into the size and the characteristics of the phenomenon remain widely lacking. The present study is the first to measure the phenomenon in one of the most prominent destination countries, Hungary, with a particular focus on the Western Hungarian region and the capital Budapest. METHOD: A questionnaire has been sent to dentists in these regions. The response rate is 25.3% in Western Hungary and 20.7% in Budapest. RESULTS: According to the survey, patients from neighbouring countries dominate dental care tourism in the border regions of Western Hungary, while Budapest attracts more patients from countries further away. In terms of motivation, dentists regard relative price levels but also service considerations as being of major importance for patients coming to Hungary for dental care. CONCLUSION: The study confirms Hungary as a centre for dental care tourism, attracting patients from bordering countries but also patients travelling longer distances. Price levels have been a major factor making Hungary an international treatment destination. With price differences narrowing down, broader service quality is increasingly emphasised as a selling strategy.

Augmented reality during robot-assisted laparoscopic partial nephrectomy: toward real-time 3D-CT to stereoscopic video registration.

OBJECTIVES: To investigate a markerless tracking system for real-time stereo-endoscopic visualization of preoperative computed tomographic imaging as an augmented display during robot-assisted laparoscopic partial nephrectomy. METHODS: Stereoscopic video segments of a patient undergoing robot-assisted laparoscopic partial nephrectomy for tumor and another for a partial staghorn renal calculus were processed to evaluate the performance of a three-dimensional (3D)-to-3D registration algorithm. After both cases, we registered a segment of the video recording to the corresponding preoperative 3D-computed tomography image. After calibrating the camera and overlay, 3D-to-3D registration was created between the model and the surgical recording using a modified iterative closest point technique. Image-based tracking technology tracked selected fixed points on the kidney surface to augment the image-to-model registration. RESULTS: Our investigation has demonstrated that we can identify and track the kidney surface in real time when applied to intraoperative video recordings and overlay the 3D models of the kidney, tumor (or stone), and collecting system semitransparently. Using a basic computer research platform, we achieved an update rate of 10 Hz and an overlay latency of 4 frames. The accuracy of the 3D registration was 1 mm. CONCLUSIONS: Augmented reality overlay of reconstructed 3D-computed tomography images onto real-time stereo video footage is possible using iterative closest point and image-based surface tracking technology that does not use external navigation tracking systems or preplaced surface markers. Additional studies are needed to assess the precision and to achieve fully automated registration and display for intraoperative use.

Empiric physiology in epidemiologic doctrines of the 18th century, Hungarian General Norm of Health in 1770.

According to standard textbooks, the last episode of European New Age plague pandemic died out by 1720 in Marseilles. Despite this allegation, the pandemic continued in well-documented new outbreaks, which attacked and devastated Central and Eastern Europe throughout the first half of the 18th century. At the beginning, military campaigns spread the infection out of the Ottoman Empire. Later on commercial goods took over this role via land or sea from Asia or out of the eastern Mediterranean region. Finally, the plague in Europe--except Russia and the Ottoman Empire--"died out" virtually by the end of the 18th century. Explaining this, there many scientific reasons were suggested: 1. Oriental rat fleas as main vectors of infection could not tolerate any more the European weather conditions (although there were no virtual climate changes in the last 300 years). 2. Black rats that lived in close proximity to man, were being outplayed by brown rats living rather outside of human habitats; 3. There emerged less virulent Yersinia strains that caused natural human immunisation. In spite of these suggestions, which may have contributed to the success, joint civil and military health authorities blocked the plague indeed, as a result of disciplined and relentless law enforcement. In Hungary, respectively in the Hapsburg Empire, well-advised health legislation backed up the effectiveness of local authorities. Following the last great devastation in 1738-1740, the General Norm of Health Service--a voluminous decree--summed up by 1770 all the time honoured empiric rules of foregoing centuries. It can be excellently demonstrated, how exactly the empiric rules discovered a century later met scientific facts of physiology and microbiology.

Study on dysphagia after proximal selective vagotomy.

The authors examined one of the characteristic complications--dysphagia--of proximal selective vagotomy widely applied in the surgical treatment of duodenal ulcerations. To gain a better knowledge of the causes of this type of complications measuring the pH value for 24 hours and manometric examinations of the lower esophageal sphincter were performed in 12 patients without complaints following operation and in 22 with the complaint of dysphagia. No significant changes were observed between the two groups either in basal sphincter pressure or in the two parameters characteristic for reflux activity, e.g. the number of reflux episodes and reflux index. Operation resulted in a slight increase of the basal pressure and the decrease of reflux activity in both groups. It is likely that postvagotomical dysphagia has a multifactorial background: denervation or mechanical trauma of the lower oesophagus and the uncoordinated and insufficient relaxation of the lower oesophageal sphincter following swallowing.

Optimized Monier-Williams method for determination of sulfites in foods: collaborative study.

A collaborative study was conducted of the Food and Drug Administration (FDA)-optimized Monier-Williams method for determining sulfites in foods. Twenty-one industry and government laboratories participated in the study, which was jointly sponsored by the National Food Processors Association and FDA. Familiarization samples were shipped to each collaborator. Collaborators were permitted to proceed to the main study only after they demonstrated ability to perform the method to ensure that the study tested the performance of the method itself and not that of the individual laboratories. The study design involved 3 food matrixes (hominy, fruit juice, and protein [seafood]). Each matrix was prepared at 3 sulfite levels--the regulatory level, half the regulatory level, twice the regulatory level--and as a blank. All test samples were analyzed as blind duplicates, which gave each collaborator a total of 24 test portions. Collaborative recoveries gave a reproducibility (among-laboratories) coefficient of variation that ranged from 15.5 to 26.6% for sulfite determined as SO2 by weight in the 3 foods at the 10 ppm level. The optimized Monier-Williams method has been approved interim official first action to replace the AOAC modified Monier-Williams method, 20.123-20.125.

[24-hour pH monitoring in the treatment of gastroesophageal reflux]. / A 24 órás pH-mérés a gastrooesophagealis reflux-betegség kezelésében.

The 24 hour pH monitoring is superior to other methods in assessing chemical activity and quantitative characteristics of gastroesophageal reflux (GER). This technique supported by the pull-through esophageal manometry, reveals and classifies the patients for either medical or surgical treatment. The comparison of the diagrams recorded before and after surgical repair, is a reliable guide in evaluating the efficacy of the anti-reflux procedure.