Incidence, features, and outcome of disease relapse after COVID-19 vaccination in patients with idiopathic inflammatory myopathies.

INTRODUCTION/AIMS: Vaccination against coronavirus disease 2019 (COVID-19) is relatively safe in patients with idiopathic inflammatory myopathies (IIM); however, myositis flares following vaccination have been poorly studied. We aimed to evaluate the frequency, features, and outcomes of disease relapses in patients with IIM following COVID-19 vaccination. METHODS: A cohort of 176 IIM patients were interviewed after the third wave of the COVID-19 pandemic and followed prospectively. Relapses were determined using the disease state criteria and the outcome of the flares with myositis response criteria, calculating the total improvement score (TIS). RESULTS: A total of 146 (82.9%) patients received a vaccination, 17/146 (11.6%) patients had a relapse within 3 mo, and 13/146 (8.9%) patients within 1 mo. The relapse rate of unvaccinated patients was 3.3%. Three months after the post-vaccination relapses, 70.6% of the patients (12/17) achieved an improvement of disease activity (average TIS score: 30 ± 15.81; seven minor, five moderate, and zero major improvements). Six months after flares improvement was detected in 15/17(88.2%) of relapsed patients (average TIS score: 43.1 ± 19.53; 3 minimal, 8 moderate, and 4 major). Forward stepwise logistic regression analysis revealed that the active state of myositis at the time of injection (p < .0001; odds ratio, 33; confidence interval, 9-120) was significantly associated with the occurrence of a relapse. DISCUSSION: A minority of the vaccinated IIM patients had a confirmed disease flare after COVID-19 vaccination and the majority of the relapses improved after individualized treatment. An active disease state at the time of vaccination probably contributes to the increased risk of a post vaccination myositis flare.

The effect of COVID-19 pandemic on idiopathic inflammatory myositis patients: a single centre experience.

OBJECTIVES: Pandemic caused by coronavirus disease (COVID-19) determines the life of clinicians and patients since 2 years. We have a lot of information about disease course, treatment and protection against virus, but less on the prognosis of infection in patients with idiopathic inflammatory myopathies (IIM). Also few data are available on triggered humoral response and side effects after vaccination. METHODS: Our goal was to assess by a retrospective cross-sectional study the above data in our cohort (176 IIM patients) by identifying COVID-19 positive patients and follow disease course. Incidence and complications of vaccination were determined by questionnaires. 101 patients volunteered for complex blood test. RESULTS: By June 1st, 2021 significantly higher incidence of COVID 19 infections (34.7%) were identified comparing to the national prevalence (8.2%). A third of these infections occurred asymptomatically or mild. Patients requiring hospitalisation had a significantly longer disease duration and a higher incidence of anti-Jo-1 antibody. All patients infected by COVID-19 became seropositive regardless the immunosuppressive therapy or symptoms severity. 54.3% of the patients received anti-COVID-19 vaccine. 72.3% of patients became seropositive after vaccination. Higher antibody titer against spike protein was detected after Pfizer-BioNTech vaccination compared to others. Patients receiving steroid therapy had decreased post-vaccination antibody response compared to those without steroid treatment. No major post-vaccination infection was observed. CONCLUSIONS: Based on our results, myositis may be associated with an increased risk of COVID-19 infection. Independent risk factor for hospitalisation are longer disease duration and anti-Jo1 positivity. Anti-SARS-CoV2 vaccines seem safe and tolerable and strongly recommended for that population.

Crack propensity of different direct restorative procedures in deep MOD cavities.

OBJECTIVE: The purpose was to evaluate the crack formation associated with different direct restorative procedures of the utilized resin composites (RC) right after and 1 week later of the restoration. MATERIALS AND METHODS: Eighty intact, crack-free third molars with standard MOD cavities were included in this in vitro study and randomly divided into four groups of 20 each. After adhesive treatment, the cavities were restored either with bulk (group 1) or layered (group 2) short-fiber-reinforced resin composites (SFRC); bulk-fill RC (group 3); and layered conventional RC (control). Right after the polymerization and a week later, crack evaluation on the outer surface of the remaining cavity walls was performed with a transillumination method utilizing the D-Light Pro (GC Europe) with the "detection mode." Between- and within-groups comparisons Kruskal-Wallis and Wilcoxon tests were used, respectively. RESULTS: Post-polymerization crack evaluation showed significantly lower crack formation in SFRC groups compared to the control (p<0.001). There was no significant difference within SFRC groups and non-SFRC groups (p=1.00 and p=0.11, respectively). Within group comparison revealed significantly higher number of cracks in all groups after 1 week (p≤0.001), however, only the control group differed significantly from all the other groups (p≤0.003). CONCLUSIONS: Post-polymerization shrinkage induced further crack formation in the tooth 1 week after the restoration. SFRC was less prone to shrinkage-related crack formation during the restorative procedure; however, after 1 week, besides SFRC, bulk-fill RC also showed less prone to polymerization shrinkage-related crack formation than layered composite fillings. CLINICAL RELEVANCE: SRFC can decrease the shrinkage stress-induced crack formation in MOD cavities.

Impact Assessment of Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) and Hemostatic Sponge on Vascular Anastomosis Regeneration in Rats.

The proper regeneration of vessel anastomoses in microvascular surgery is crucial for surgical safety. Pituitary adenylate cyclase-activating polypeptide (PACAP) can aid healing by decreasing inflammation, apoptosis and oxidative stress. In addition to hematological and hemorheological tests, we examined the biomechanical and histological features of vascular anastomoses with or without PACAP addition and/or using a hemostatic sponge (HS). End-to-end anastomoses were established on the right femoral arteries of rats. On the 21st postoperative day, femoral arteries were surgically removed for evaluation of tensile strength and for histological and molecular biological examination. Effects of PACAP were also investigated in tissue culture in vitro to avoid the effects of PACAP degrading enzymes. Surgical trauma and PACAP absorption altered laboratory parameters; most notably, the erythrocyte deformability decreased. Arterial wall thickness showed a reduction in the presence of HS, which was compensated by PACAP in both the tunica media and adventitia in vivo. The administration of PACAP elevated these parameters in vitro. In conclusion, the application of the neuropeptide augmented elastin expression while HS reduced it, but no significant alterations were detected in collagen type I expression. Elasticity and tensile strength increased in the PACAP group, while it decreased in the HS decreased. Their combined use was beneficial for vascular regeneration.

Multimodal Assessment of the Pulse Rate Variability Analysis Module of a Photoplethysmography-Based Telemedicine System.

Alterations of heart rate variability (HRV) are associated with various (patho)physiological conditions; therefore, HRV analysis has the potential to become a useful diagnostic module of wearable/telemedical devices to support remote cardiovascular/autonomic monitoring. Continuous pulse recordings obtained by photoplethysmography (PPG) can yield pulse rate variability (PRV) indices similar to HRV parameters; however, it is debated whether PRV/HRV parameters are interchangeable. In this study, we assessed the PRV analysis module of a digital arterial PPG-based telemedical system (SCN4ALL). We used Bland-Altman analysis to validate the SCN4ALL PRV algorithm to Kubios Premium software and to determine the agreements between PRV/HRV results calculated from 2-min long PPG and ECG captures recorded simultaneously in healthy individuals (n = 33) at rest and during the cold pressor test, and in diabetic patients (n = 12) at rest. We found an ideal agreement between SCN4ALL and Kubios outputs (bias < 2%). PRV and HRV parameters showed good agreements for interbeat intervals, SDNN, and RMSSD time-domain variables, for total spectral and low-frequency power (LF) frequency-domain variables, and for non-linear parameters in healthy subjects at rest and during cold pressor challenge. In diabetics, good agreements were observed for SDNN, LF, and SD2; and moderate agreement was observed for total power. In conclusion, the SCN4ALL PRV analysis module is a good alternative for HRV analysis for numerous conventional HRV parameters.

Fracture behavior of root-amputated teeth at different amount of periodontal support - a preliminary in vitro study.

BACKGROUND: The purpose of this study was to evaluate the effect of the amount of periodontal support on the fracture resistance of root-amputated maxillary molar teeth restored with either direct class. I. restorations or class II. mesio-occluso-distal (MOD) indirect overlay restorations with cuspal coverage. METHODS: Sixty sound maxillary first molars were collected and randomly divided into four groups. In Groups 1 and 2, MOD cavities were prepared and all cusps were reduced by 2 mm, whereas in Group 3 and 4, only a conservative Class I. cavity was prepared. Subsequently, root canal treatment was performed and the mesio-buccal roots were amputated. Groups 1 and 2 were restored with indirect composite overlay, while Groups 3 and 4 received direct composite fillings. After restoration, teeth were embedded as follows: Groups 1 and 3: normal bone level, Groups 2 and 4: furcation involvement. The specimens were submitted to static fracture resistance testing. Fracture thresholds and fracture patterns were measured and evaluated. RESULTS: Group 1 had the highest fracture resistance (2311,6 N) among the restored groups and showed statistically significant difference compared to Group 2 (p = 0.038) and Group 4 (p = 0.011). There was no statistically significant difference in terms of fracture resistance between the rest of the groups. In terms of the fracture patterns, Group 3 was characterized by the highest percentage (60%) of mostly favorable fractures, while the rest of the groups showed predominantly unfavorable ones. CONCLUSIONS: The amount of periodontal support seems to influence the fracture resistance of root-amputated and restored maxillary molars.

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.

Frustrated packing in a granular system under geometrical confinement.

Optimal packings of uniform spheres are solved problems in two and three dimensions. The main difference between them is that the two-dimensional ground state can be easily achieved by simple dynamical processes while in three dimensions, this is impossible due to the difference in the local and global optimal packings. In this paper we show experimentally and numerically that in 2 + ε dimensions, realized by a container which is in one dimension slightly wider than the spheres, the particles organize themselves in a triangular lattice, while touching either the front or rear side of the container. If these positions are denoted by up and down the packing problem can be mapped to a 1/2 spin system. At first it looks frustrated with spin-glass like configurations, but the system has a well defined ground state built up from isosceles triangles. When the system is agitated, it evolves very slowly towards the potential energy minimum through metastable states. We show that the dynamics is local and is driven by the optimization of the volumes of 7-particle configurations and by the vertical interaction between touching spheres.

Heaping, secondary flows and broken symmetry in flows of elongated granular particles.

In this paper we report experiments where we shear granular rods in split-bottom geometries, and find that a significant heap of height of least 40% of the filling height can form at the particle surface. We show that heaping is caused by a significant secondary flow, absent for spherical particles. Flow reversal transiently reverses the secondary flow, leading to a quick collapse and slower regeneration of the heap. We present a symmetry argument and experimental data that show that the generation of the secondary flow is driven by a misalignment of the mean particle orientation with the streamlines of the flow. This general mechanism is expected to be important in all flows of sufficiently anisometric grains.

Is it possible to differentiate between Takotsubo cardiomyopathy and acute anterior ST-elevation myocardial infarction?

INTRODUCTION: Several studies have investigated the ability of the twelve-lead electrocardiogram (ECG) to reliably distinguish Takotsubo cardiomyopathy (TC) from an acute anterior ST-segment elevation myocardial infarction (STEMI). In these studies, only ECG changes were required - ST-segment deviation and/or T-wave inversion - in TC whereas in acute anterior STEMI, ECGs had to meet STEMI criteria. In the majority of these studies, patients of both genders were used even though TC predominantly occurs in women. The aim of this study is to see whether TC can be distinguished from acute anterior STEMI in a predominantly female study population where all patients meet STEMI-criteria. METHODS: Retrospective analysis of the ST-segment changes was done on the triage ECGs of 37 patients with TC (34 female) and was compared to the triage ECGs of 103 female patients with acute anterior STEMI. The latter group was divided into the following subgroups: 46 patients with proximal, 47 with mid and 10 with distal LAD occlusion. Three ST-segment based ECG features were investigated: (1) Existing criterion for differentiating anterior STEMI from TC: ST-segment depression >0.5mm in lead aVR+ST-segment elevation ≤1mm in lead V1, (2) frontal plane ST-vector and (3) mean amplitude of ST-segment deviation in each lead. RESULTS: The existing ECG criterion was less accurate (76%) than in the original study (95%), with a large difference in sensitivity (26% vs. 91%). Only a frontal plane ST-vector of 60° could significantly distinguish TC from all acute anterior STEMI subgroups (p<0.01) with an overall diagnostic accuracy of 81%. The mean amplitude in inferior leads II and aVF was significantly higher for patients with TC compared to all patients with acute anterior STEMI (p<0.01 and p<0.05 respectively) and the mean amplitude in the precordial leads V1 and V2 was significantly lower compared to proximal and mid LAD occlusion (p<0.01). CONCLUSIONS: Given the consequences of missing the diagnosis of an acute anterior STEMI the diagnostic accuracy of the ECG criteria investigated in this retrospective study were insufficient to reliably distinguish patients with TC from patients with an acute anterior STEMI. To definitely exclude the diagnosis of an acute anterior STEMI coronary angiography, which remains the gold standard, will need to be performed.

Effects of grain shape on packing and dilatancy of sheared granular materials.

A granular material exposed to shear shows a variety of unique phenomena: Reynolds dilatancy, positional order and orientational order effects may compete in the shear zone. We study granular packing consisting of macroscopic prolate, oblate and spherical grains and compare their behaviour. X-ray tomography is used to determine the particle positions and orientations in a cylindrical split bottom shear cell. Packing densities and the arrangements of individual particles in the shear zone are evaluated. For anisometric particles, we observe the competition of two opposite effects. On the one hand, the sheared granules are dilated, on the other hand the particles reorient and align with respect to the streamlines. Even though aligned cylinders in principle may achieve higher packing densities, this alignment compensates for the effect of dilatancy only partially. The complex rearrangements lead to a depression of the surface above the well oriented region while neighbouring parts still show the effect of dilation in the form of heaps. For grains with isotropic shapes, the surface remains rather flat. Perfect monodisperse spheres crystallize in the shear zone, whereby positional order partially overcompensates dilatancy effects. However, even slight deviations from the ideal monodisperse sphere shape inhibit crystallization.

Robots for surgeons? Surgeons for robots? Exploring the acceptance of robotic surgery in the light of attitudes and trust in robots.

BACKGROUND: Over the last century, technological progress has been tremendous, and technological advancement is reflected in the development of medicine. This research assessed attitudes towards surgical robots and identified correlations with willingness to participate in robotic surgery based on factors influencing trust in automated systems. METHOD: Using data from a survey, which included the Multi-dimensional Robot Attitude Scale (MdRAS) and a questionnaire consisting of attitude statements regarding the factors affecting trust in automated systems, the experiment assessed the attitudes of healthcare workers and potential patients towards surgery robots, and attempted to find a correlation between these attitudes, age, and gender. RESULTS AND CONCLUSION: Statistical evaluation of the responses (N = 197) showed that positive attitude towards surgical robots showed a high correlation with the willingness to participate in robotic surgery and gave the strongest correlations with the MdRAS utility and negative attitude towards robots subscales. For the assessment of willingness, the MdRAS subscales alone did not provide a strong enough correlation. All factors examined showed a significant correlation with participation. Having faith in the surgery robot, the propensity to trust technology, the designer's reputation, the ease of work that a surgical robot provides, positive experience with robots, and believing the surgeon is competent at operating the machine seemed to have been the most important positive correlations, while fear of errors gave the highest negative correlation. The healthcare workers and potential patients showed significant differences in the subscales of the questionnaire perceived risk and knowledge but no significant difference in the characteristics of the surgical robot. There was no difference in willingness to participate between the samples. Age did not show a significant correlation with the score achieved and willingness in any of the samples. Significant differences were found between male and female respondents, with men having more positive attitudes and being more likely to participate in surgeries using surgery robots than women. As a result, the research potentially sheds light on the factors that need to be considered when building trust in robotic surgery.

Mechanical Performance of Extensive Restorations Made with Short Fiber-Reinforced Composites without Coverage: A Systematic Review of In Vitro Studies.

In recent years, composite resin materials have been the most frequently used materials for direct restorations of posterior teeth. These materials have some clinically relevant limitations due to their lack of fracture toughness, especially when used in larger cavities with high volume factors or when utilized as direct or indirect overlays or crown restorations. Recently, short-fiber-reinforced composite materials have been used in bi-structure restorations as a dentine substituting material due to their superior mechanical properties; however, there is no scientific consensus as to whether they can be used as full restorations. The aim of our review was to examine the available literature and gather scientific evidence on this matter. Two independent authors performed a thorough literature search using PubMed and ScienceDirect up until December 2023. This study followed the PRISMA guidelines, and the risk of bias was assessed using the QUIN tool. The authors selected in vitro studies that used short-fiber-reinforced composite materials as complete restorations, with a conventional composite material as a comparison group. Out of 2079 potentially relevant articles, 16 met our inclusion criteria. All of the included studies reported that the usage of short-fiber-reinforced composites improved the restoration's load-bearing capacity. Fifteen of the included publications examined the fracture pattern, and thirteen of them reported a more favorable fracture outcome for the short-fiber-reinforced group. Only one article reported a more favorable fracture pattern for the control group; however, the difference between groups was not significant. Within the limitations of this review, the evidence suggests that short-fiber-reinforced composites can be used effectively as complete restorations to reinforce structurally compromised teeth.

Dopamine Transporter SPECT with 12-Minute Scan Duration Using Multiple-Pinhole Collimators.

This study evaluated the potential to reduce the scan duration in dopamine transporter (DAT) SPECT when using a second-generation multiple-pinhole (MPH) collimator designed for brain SPECT with improved count sensitivity and improved spatial resolution compared with parallel-hole and fanbeam collimators. Methods: The retrospective study included 640 consecutive clinical DAT SPECT studies that had been acquired in list mode with a triple-head SPECT system with MPH collimators and a 30-min net scan duration after injection of 181 ± 10 MBq of [123I]FP-CIT. Raw data corresponding to scan durations of 20, 15, 12, 8, 6, and 4 min were obtained by restricting the events to a proportionally reduced time interval of the list-mode data for each projection angle. SPECT images were reconstructed iteratively with the same parameter settings irrespective of scan duration. The resulting 5,120 SPECT images were assessed for a neurodegeneration-typical reduction in striatal signal by visual assessment, conventional specific binding ratio analysis, and a deep convolutional neural network trained on 30-min scans. Results: Regarding visual interpretation, image quality was considered diagnostic for all 640 patients down to a 12-min scan duration. The proportion of discrepant visual interpretations between 30 and 12 min (1.2%) was not larger than the proportion of discrepant visual interpretations between 2 reading sessions of the same reader at a 30-min scan duration (1.5%). Agreement with the putamen specific binding ratio from the 30-min images was better than expected for 5% test-retest variability down to a 10-min scan duration. A relevant change in convolutional neural network-based automatic classification was observed at a 6-min scan duration or less. Conclusion: The triple-head SPECT system with MPH collimators allows reliable DAT SPECT after administration of about 180 MBq of [123I]FP-CIT with a 12-min scan duration.

[Evolution of sentinel lymph node biopsy in breast cancer--axillary staging in the past 15 years at the Uzsoki Street Hospital]. / Hová tartasz sentinelbiopszia, avagy az elmúlt 15 év gyakorlata az axilla ellátásában az Uzsoki Utcai Kórházban.

INTRODUCTION: Sentinel biopsy technique was performed in Europe in 1996.It was a great improvement in the surgical treatment of breast cancer, it decreased the number of patients suffering from early and late morbidity following axillary lymph node dissection (ALND). In our paper we demonstrate the evolution of sentinel biopsy technique (SLNB), as well as the changes in our policy on axillary treatment in line with the European trends. METHODS: The authors of this article give an overview and analyse the relevant literature concerning sentinel lymph node biopsy and data of patients on whom sentinel lymph node biopsy was performed from 01/01/2001 to 31/12/2012. RESULTS: Between 2001 and 2013 we performed 3756 breast operations, 2742 of those were done for malignant disease. Altogether we performed 744 sentinel lymph node biopsies in the Uzsoki teaching Hospital. The proportion of SLNB patients is increasing, it was 24.6% between 2001-2006 and 29.2% between 2007-2012, respectively. The indication of SLNB is widening, there might be justification of the technique even by multifocal or multilocular disease, in male patients, after former breats surgery or even in pregnant patients. CONCLUSION: Histological examination of sentinel lymph node and its effect on complex treatment of breats cancer may place the role of surgical axillary staging in a brand new aspect in the near future perhaps.

Cost dynamics of helicopter emergency services: A Hungarian example.

Objectives: Helicopter emergency medical services (HEMS) have been integral to healthcare systems in developed countries and are becoming more relevant in developing countries. There is extremely scarce information available regarding the typical cost structure and dynamics of HEMS operation; thus, the limitation of knowledge may limit the shapers of national healthcare policy and potential private operators in starting such a service. This study aims to present the cost dynamics of HEMS operation. Methods: A systematic literature review was performed on open-source studies to obtain appropriate data. International benchmarks were found; nevertheless, as Hungarian data did not emerge, a recent investment into HEMS service was analyzed based on publicly available data from the Hungarian Air Ambulance and affiliated companies. The resulting cost base was allocated per flight hour, and a scenario was established with Western European (German) wages and salaries to challenge the aforementioned international examples. Results: The average cost of operation is calculated at EUR 2488 per hour or EUR 41.5 per airborne minute based on average mission duration. This result is quite below the German example of ca. EUR 55.4 per airborne minute and even less than the US and Australian examples, but once the costing model was recalculated with German salaries, the result was extremely similar to the literature review. Nevertheless, comparable international figures need further research, as ownership structure, cost allocation method, and accounting regimes may dramatically impact the cost per airborne minute. Conclusion: The cost of EUR 2488 per flight hour is a good indicator for an hourly rate of operations; however, when deciding on establishing such a service, the model needs to be adjusted for comparable salaries and foreign exchange rates. Nevertheless, if the number of flight hours can be well estimated, the yearly funding needs can be accurately determined using it.

Travel Patterns and Motivations of the Hungarian Gay and Lesbian Community.

Tourism plays a key role for gay people, as it is not only a way to escape from work, but also a source of liberation and self-embracement. This role can be particularly valued in societies and political environments that are perceived as hostile toward this group. The present study examines the travel motivations and habits of gay and lesbian people, based on a questionnaire sample of 1473 respondents. The results show that for this group, but especially for women, acceptance and an open culture are of paramount importance when choosing a destination. In contrast, services and events specifically targeted at this sector, which are popular in the Western world, do not typically influence decision-making (they tend to be more attractive to women). Sex per se is not a travel motivator for this group, but is an important feature of travel for men. In addition to gender, the services and activities that an individual engages in while traveling are influenced by the degree of their sexual embracement, the place of residence and the company with which the individual travels.

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.

Performance evaluation of a novel multi-pinhole collimator on triple-NaI-detector SPECT/CT for dedicated myocardial imaging.

BACKGROUND: In this study we evaluated the imaging capabilities of a novel Multi-pinhole collimator (MPH-Cardiac) specially designed for nuclear cardiology imaging on a Triple-NaI-detector based SPECT/CT system. METHODS: 99mTc point source measurements covering the field of view (FOV) were used to determine tomographic sensitivity (TSpointsource) and spatial resolution. Organ-size tomographic sensitivity (TSorgan) was measured with a left ventricle (LV) phantom filled with typical myocardial activity of a patient scan. Reconstructed image uniformity was measured with a 140 mm diameter uniform cylinder phantom. Using the LV phantom once filled with 99mTc and after with 123I, Contrast-to-noise ratio (CNR) was measured on the reconstructed images by ROI analysis on the myocardium activity and on the LV cavity. Furthermore, a polar map analysis was performed determining Spill-Over-Ratio in water (SORwater) and image noise. The results were compared with that of a dual-head parallel-hole low energy high resolution (LEHR) collimator system. A patient with suspected coronary artery disease (CAD) was scanned on the LEHR system using local protocol of 16 min total acquisition time, followed by a 4-min MPH-Cardiac scan. RESULTS: Peak TSpointsource was found to be 1013 cps/MBq in the axial center of the FOV while it was decreasing toward the radial edges. TSorgan in the CFOV was found to be 134 cps/MBq and 700 cps/MBq for the LEHR and MPH-Cardiac, respectively. Average spatial resolution throughout the FOV was 4.38 mm FWHM for the MPH-Cardiac collimator. Reconstructed image uniformity values were found to be 0.292% versus 0.214% for the LEHR and MPH-Cardiac measurements, respectively. CNR was found to be higher in case of MPH-Cardiac than for LEHR in case of 99mTc (15.5 vs. 11.7) as well as for 123I (13.5 vs. 8.3). SORwater values were found to be 28.83% and 21.1% for the 99mTc measurements, and 31.44% and 24.33% for the 123I measurements for LEHR and MPH-Cardiac, respectively. Pixel noise of the 99mTc polar maps resulted in values of 0.38% and 0.24% and of the 123I polar maps 0.62% and 0.21% for LEHR and MPH-Cardiac, respectively. Visually interpreting the patient scan images, MPH-Cardiac resulted in better image contrast compared to the LEHR technique with four times shorter scan duration. CONCLUSIONS: The significant image quality improvement achieved with dedicated MPH-Cardiac collimator on triple head SPECT/CT system paves the way for short acquisition and low-dose cardiovascular SPECT applications.

Orientational order and alignment of elongated particles induced by shear.

Shear induced alignment of elongated particles is studied experimentally and numerically. We show that shear alignment of ensembles of macroscopic particles is comparable even on a quantitative level to simple molecular systems, despite the completely different types of particle interactions. We demonstrate that for dry elongated grains the preferred orientation forms a small angle with the streamlines, independent of shear rate across three decades. For a given particle shape, this angle decreases with increasing aspect ratio of the particles. The shear-induced alignment results in a considerable reduction of the effective friction of the granular material.