In this study, we explored psychometric network analysis (PNA) as an alternative method for identifying item wording effects in self-report instruments. We examined the functioning of negatively ...worded items in the network structures of two math-related scales from the 2019 Trends in International Mathematics and Science Study (TIMSS); Students Like Learning in Mathematics (SLLM); and Students Confident in Mathematics (SCM). We also explored how the negatively worded items functioned in network structures across demographic subgroups. Data were drawn from eight countries that represented diverse levels of math performance and cultural attitudes toward school ( n = 75,972). We found that negatively worded items were distinct from the positively worded items in the SLLM and SCM item networks, and that this effect was consistent across all age- and country-level subgroups. Based on these findings, we recommend PNA as a data-driven approach for detecting wording effects effectively.
The rapid increase in the number of electronic products worldwide, in terms of both variety and advanced technology, together with the decrease in costs, has led to the generation of a large amount ...of electronic waste (e-waste), which has significantly increased environmental pollution. This study was conducted to investigate the hypothesis that the adhesion of polymer binders and plastic origin e-waste will be more effective and stronger, and therefore have a positive effect on the permeability properties of polymer concrete and its behavior against aggressive solutions. For this purpose, quartz aggregates and gravel used as an aggregate in polymer concrete were replaced with 0%, 3%, 6%, 9%, 12% and 15% e-waste. In the study where unsaturated polyester resin was used as a binder, the changes in the permeability properties (capillary water absorption, rapid chloride permeability) of the e-waste polymer concrete and its behavior against aggressive solutions (acid and sulfate attacks) were evaluated after 7, 28 and 90 days. In addition, mechanical experiments were conducted and comparisons were made. After the control concrete, the highest compressive strengths were obtained from the polymer concrete specimens using 3% e-waste, measured as 59.05 MPa, 64.5 MPa and 73.05 MPa after 7, 28 and 90 days, respectively. The research showed that polymer concretes with capillary water absorption coefficient values close to zero after 90 days can be produced with using up to 9% e-waste. The use of e-waste as an aggregate in polymer concrete at 3%, 6% and 9% e-waste, in particular, produced concrete with a high resistance to acid and sulfate attacks. The hypothesis of the study was confirmed after extensive experiments.
Graphical Abstract
Various studies have reported a significant reduction in tensile bond strength of brackets when bonding is carried out immediately after bleaching. The purpose of this investigation was to determine ...the effect of an antioxidant agent on the tensile bond strength values of metal brackets bonded with composite resin to human enamel after bleaching with carbamide peroxide (CP). A total of 80 extracted premolar teeth were randomly divided into three bleaching groups of 10 per cent CP and an unbleached control group. The specimens in group 1 were bonded immediately after bleaching; group 2 were stored in an artificial saliva solution for 7 days after bleaching; group 3 were treated with 10 per cent sodium ascorbate, immediately before bonding, whereas the unbleached specimens in group 4 had no treatment before bonding. Tensile bond strengths were established in MPa. To evaluate the amount of resin left on the enamel surfaces after debonding, the adhesive remnant index (ARI) scores were used. The tensile bond strength data were analyzed with the Kruskal–Wallis test and pairwise comparisons were made by the Mann–Whitney U test at a significance level of P < 0.05. The brackets bonded immediately after bleaching revealed significantly lower tensile bond strengths than those of unbleached enamel (P = 0.000). No statistically significant differences in tensile bond strength were noted when the delayed-bonding (P = 6.000) and antioxidant-treated (P = 0.2757) groups were compared with the control group. The antioxidant treatment immediately after bleaching was effective in reversing the tensile bond strength of brackets.
Case report.
To present a case of primary hydatid cyst in the lumbar subcutaneous tissue affecting posterior paravertebral muscle and mimicking disc herniation.
Cystic hydatid disease is a rare but ...significant parasitic disease in endemic areas. Musculoskeletal or soft tissue hydatidosis accounts for about 0.5% to 5% of all echinococcal infections in endemic areas and is almost secondary to the hepatic or pulmonary disease. Primary lumbar subcutaneous hydatid cyst affecting paravertebral muscle and extending to neural foramina is a very rare condition even in endemic areas.
A 25-year-old-female patient was admitted with swelling and pain in the right lumbar region for 3 months. The pain was reflecting in the right gluteal region and the right leg. Lumbar extension and right lateral flexion was painful and straight leg raising test was positive at right side. There was a mild hypoesthesia at L5 dermatome. According to the magnetic resonance image that the clinician obtained for initial diagnosis of lumbar disc herniation, we found multi-cystic masses located at the right paravertebral muscle at the level of L3-L5 which extended to L4-L5 neural foramina and at subcutaneous tissue at the right gluteal region.
The patient was operated for the purpose of removal of cysts. Postoperatively, diagnosis of hydatid cyst was confirmed by histopathology.
By this case, we emphasize that cystic hydatid disease should be taken into consideration in the differential diagnosis of low back pain and could mimic disc herniation.
N/A.
Polycrystalline alumina ceramic orthodontic brackets were coated with anatase TiO₂ film via a sol-gel dip-coating method. The surface structure morphology and composition of the films were evaluated ...via scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The antimicrobial activity of the ceramic brackets was assessed against two oral pathogens, S. mutans and C. albicans. The results demonstrated that TiO₂-coated brackets exposed to low energy UV-A illumination efficiently reduced the populations of test microorganisms relative to the uncoated brackets. The reduction efficiencies were 98% for S. mutans ATCC 10449 and 93% for C. albicans ATCC 60193.
Objectives
The instruments used in endoscopic surgery include rigid endoscopes of different diameters and angles, sources of light and monitors. In this study, we explored temperature rises in the ...round window caused by insertion of rigid endoscopes of different diameters into the middle ear; the endoscopes were fitted with different light sources.
Design
An experimental animal study.
Setting
We subjected seven guinea pigs to simulate otological surgery at room temperature. We monitored body temperatures, along with temperature rises caused by the use of 0° rigid endoscopes of diameters 3 or 4 mm, fitted with light sources including a halogen light, a light‐emitting diode (LED) and a xenon light. Data were collected every second from a sensor placed in the round window.
Participants
An experimental study on 7 guinea pigs.
Main Outcome Measures
Rise of the temperature on round window.
Results
Rigid endoscopes caused the temperature of the tympanum to rise when xenon and halogen light sources were used, regardless of endoscope diameter. However, the temperature rise was less when a LED light source was employed.
Conclusion
The endoscopic instruments used in middle ear surgery caused the temperature of the round window to rise. The rise varied with endoscope diameter and the type of light source used.
This study investigates the alkali-silica reaction (ASR) and mechanical properties of mortars containing crumb and powder rubber instead of river sand. In this regard, mortars were produced using ...waste rubber whose ratios in the mixture are 0%, 3%, 6%, 9%, 12%, 15%, 18%, and 21%. ASR expansion, compressive and flexural strength tests were conducted on the samples. ASR measurements were performed on days 3, 7, 14, 21, and 28. Besides, at the end of the ASR experiment, the microstructures of the mortars were examined using scanning electron microscope (SEM) images. Examining the results of this study reveals that the use of waste rubber in rising portions in the mortars led to an increase in the ASR expansions of the mortars. The study shows that the ASR expansions of the mortar samples that have 9% and 15% waste rubber replacement are comparatively higher than the other mortar samples. Furthermore, the results of the SEM analysis verified this finding. The study demonstrates that 3% of waste rubber mortar samples have the highest compressive and flexural strengths. On the other side, the ASR expansion of the mortars with 3% substituted waste rubber was considerably low compared to other mortars containing waste rubber. These findings (ASR, compressive and flexural strength tests results) show that using 3% waste rubber is ideal for producing mortars and supports a sustainable production approach in the sector.
This article presents the results of a comprehensive study investigating the hypothesis that higher concentrations of natural radionuclides, that are harmful to human health, may be present in ...Self-Compacting Concretes (SCCs) due to its higher powder material content compared to conventional concretes. The fresh (slump-flow, T500 time, V-funnel) concrete and compressive strength of SCCs prepared by replacing Portland cement with fly ash (FA), silica fume (SF), and ground granulated blast furnace slag (GGBFS) in the respective range of 5%, 12.5%, and 20% were determined. The radionuclide activity concentration of all solid concrete components and SCCs were determined using the gamma spectrometry method. Radioactivity analyses including the calculation of the activity concentration index and annual effective dose equivalents were also performed. The findings showed that the specimens with the highest average compressive strength at the end of 120th day were, respectively, SF (54.2 MPa), FA (52.2 MPa) and GGBFS (46.1 MPa) added to the SCC. The obtained concentration of the Radium-226 value (41.1) of 20% UK with added SCC was 1.8 times higher than the control concrete (22.7) and 2 times higher than 20% SF added SCC (19.7). The highest Radium equivalent activity (Raeq) values were FA20 (89.52), GGBFS20 (72.05), control concrete (70.86) and SF20 (68.01). It was determined that the FA selected for the study exceeded the limit specified for structural material (3.38 > 1) and fell in the radiologically hazardous class. It has been proven that SF can be used as a radioactivity reducing material of concretes. The results revealed that the research hypothesis was confirmed in terms of FA.
Display omitted
•The rheology of SCCs are affected by the type and ratio of the mineral additives.•SCC gained high compressive strength by GGBFS at early, FA at later, SF at all ages.•FA entered the radiologically dangerous class and exceeded the limit.•SF had the lowest annual effective dose equivalents.•SF can be used as a reducing material against radioactivity.
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