T2 Test Research Articles

Microleakage of five separated nickel-titanium rotary file systems in the apical portion of the root canal

The aim of this study was to evaluate the rate of apical microleakage following the fracture of five types of nickel-titanium rotary file systems (ProTaper Universal, Mtwo, RaCe, Revo-s, HeroShaper) in the apical one-third of the canal. In this laboratory experiment, 49 mandibular premolars were collected and randomly divided into seven groups. Root canal treatment was performed by five different rotary file systems with different cross-sections. All files, except in the control groups, were scratched at the 3-mm end by a handpiece. After separation of the apical end of the file in the root canal, the apical seal was measured, using the fluid infiltration technique. Data were analyzed in SPSS, using one-way ANOVA and Tamhane's T2 tests at P < 0.05. The Hero Shaper and RaCe files showed the highest (3.14 μL/min) and the lowest (2.51 µL/min) rates of microleakage over time, respectively. There were significant differences between the Hero Shaper and RaCe files and between Hero Shaper and ProTaper files in terms of microleakage (Tamhane's T2 tests, P < 0.05). The presence of a separated file and its cross-section type affects the apical microleakage.

The Effectiveness of E-Module on Buffer Solutions to Improve Students' Higher-Order Thinking Skills and Self-Regulated Learning

This study aims to determine the difference between Higher Order Thinking Skills (HOTS) and Students Self Regulated Learning (SRL) before and after using e-module based on the 7E (elicit, engage, explore, explain, elaborate, evaluate, and extend) learning cycle on the buffer solution material, and to determine the percentage of its effectiveness. The research use a quasi experiment with one-group pretest-posttest design. The subjects of this research were students of natural science 11th grade in one of senior high schools in Yogyakarta. The instrument used were test in the form of HOTS pretest-posttest description question and non-test in the form of self-regulated learning questionnaire. The data analysis technique used is Hotteling's T2 test. The results showed that the significance value was 0.000 &lt; = 0.05, then H0 was rejected. There were differences in students' HOTS and SRL before and after using e-module based on the 7E learning cycle. The effectiveness of using e-module show by HOTS and SRL simultaneously (36.8%), HOTS (25.2%), and SRL (20.5%).

HIV Viral Suppression among People Living with HIV on Antiretroviral Therapy in Haut-Katanga and Kinshasa Provinces of Democratic Republic of Congo.

Human immunodeficiency virus (HIV) infections and less-than-optimal care of people living with HIV (PLHIV) continue to challenge public health and clinical care organizations in the communities that are most impacted by HIV. In the era of evidence-based public health, it is imperative to monitor viral load (VL) in PLHIV according to global and national guidelines and assess the factors associated with variation in VL levels. Purpose: This study had two objectives—(a) to describe the levels of HIV VL in persons on antiretroviral therapy (ART), and (b) to analyze the significance of variation in VL by patients’ demographic and clinical characteristics, outcomes of HIV care, and geographic characteristics of HIV care facilities. Methods: The study population for this quantitative study was 49,460 PLHIV in the Democratic Republic of Congo (DRC) receiving ART from 241 CDC-funded HIV/AIDS clinics in the Haut-Katanga and Kinshasa provinces of the DRC. Analysis of variance (ANOVA) was performed, including Tamhane’s T2 test for pairwise comparisons using de-identified data on all patients enrolled in the system by the time the data were extracted for this study by the HIV programs in May 2019. Results: The VL was undetectable (<40 copies/mL) for 56.4% of the patients and 24.7% had VL between 40 copies/mL and less than 1000 copies per mL, indicating that overall, 81% had VL < 1000 and were virologically suppressed. The remaining 19% had a VL of 1000 copies/mL or higher. The mean VL was significantly (p < 0.001) higher for males than for females (32,446 copies/mL vs. 20,786, respectively), persons <15 years of age compared to persons of ages ≥ 15 years at the time of starting ART (45,753 vs. 21,457, respectively), patients who died (125,086 vs. 22,090), those who were lost to follow-up (LTFU) (69,882 vs. 20,018), those with tuberculosis (TB) co-infection (64,383 vs. 24,090), and those who received care from urban clinics (mean VL = 25,236) compared to rural (mean VL = 3291) or semi-rural (mean VL = 26,180) clinics compared to urban. WHO clinical stages and duration on ART were not statistically significant at p ≤ 0.05 in this cohort. Conclusions: The VL was >1000 copies/mL for 19% of PLHIV receiving ART, indicating that these CDC-funded clinics and programs in the Haut-Katanga and Kinshasa provinces of DRC have more work to do. Strategically designed innovations in services are desirable, with customized approaches targeting PLHIV who are younger, male, those LTFU, with HIV/TB co-infection, and those receiving care from urban clinics.

Comparison of Silane Heat Treatment by Laser and Various Surface Treatments on Microtensile Bond Strength of Composite Resin/Lithium Disilicate.

In the current study, we evaluated the effects of heat treatment (by Er:YAG or furnace) and various surface treatments on the microtensile bond strength (μTBS) of silanized lithium disilicate ceramic. Seventy lithium disilicate (IPS e. max Press; Ivoclar Vivadent) and composite resin (Tetric N-Ceram; Ivoclar Vivadent) blocks were made and distributed into seven groups (n = 10) at random: S: silanization alone; ALS: airborne particle abrasion (APA) and silanization; SC: APA modified with silica and silanization; SHT1: silanization and heat treatment by Er:YAG; SHT2: silanization and heat treatment performed in the furnace (100 °C, 1 min); HF: etching with HF; and HFS: etching with HF and silanization. Every ceramic specimen was cemented to a composite resin block after surface treatment. Cemented specimens were embedded into acrylic resin and were tested with the μTBS test. Data were analyzed using one-way ANOVA and Tamhane T2 tests (α = 0.05). The SHT1 group had the highest bond of strength compared to the other groups (27.46 MPa). The ALS group had the lowest strength of the groups (15.56 MPa). Between SHT2 and HFS (p = 1), the comparison of the mean µTBS values showed no significant differences. It was concluded that silane heat treatment increased the resin composite–ceramic bond strength; however, within the terms of μTBS, the Er:YAG laser treatment was more successful than other surface treatment applications.

The Development of the Democratic Behavior Scale: A Validity and Reliability Study

This study aimed to develop a scale to determine the democratic behavior levels of children in early childhood. The study group included a total of 486 children attending kindergartens and primary school nursery classes in Melikgazi, Kayseri. Scale reliability was tested by using intra-group correlation values, item analysis coefficients, Cronbach’s Alpha reliability coefficient (0,98), and the Hotelling T2 test result [ 830,12 and (p&lt;0.001)]. For validity testing purposes, the Cronbach Alpha coefficient, KMO test result (0,97), the Bartlett test and item analysis (p&lt;0.001) were calculated. It was consequently decided that the scale was suitable for factoring, and AFA was used in principal component analyses. Following this, the structural equation model of DFA was performed, which confirmed that the model suited the data and that the 3-factor structure of the scale was valid. Confirmed as valid and reliable, the scale consisted of a total of 38 items in the sub-dimensions of "Knowing Your Rights", "Autonomous Behaviors" and "Democratic Behaviors". The highest score possible from the scale is 190, while the lowest possible score is 38.

Utilizing two-dimensional gas chromatography time of flight mass spectrometry (GCxGC ToFMS) to characterize volatile products from pyrolysis of living vegetation foliage

Wildland fire can cause significant damage but is also a natural process that is key to the healthy functioning of many ecosystems worldwide. Primary fuels for a wildland fire are the dead foliage and small branches which accumulate as litter on the ground. A cone calorimeter was used to measure the various aspects of these fuels. A single sample of preignition gases from the live leaves of seven plant species were vacuum collected on quality filters and within super-chilled solvent mixtures. GC-TOFMS (1D) and GCxGC-TOFMS (2D) were used to characterize the “white” smoke emissions. The vegetation chemicals were separated into 4 categories: hydrocarbons (CH), oxygenated organics (CHO), unknown peaks (UNK), and organic non-metals (ONM). The multivariate paired Hotelling T2 test determined that the composition of the white smoke as described by the relative number of peaks in the four chemical groups differed significantly between 1D and 2D (Prob &gt; F3,4 = 0.00004). In contrast, the relative peak area percentages in the four chemical groups did not differ between 1D and 2D (Prob &gt; F3,4 = 0.1258). The Molecular Chemical Maps (MCMs) were used to identify chemical trends between the known and unknown chemicals in live oak and longleaf pine. Application of the 2D technique may provide more detailed information necessary to improve the numerical modeling of wildland fire behavior and emissions production.

Financial Performance of Telecommunication Sector Companies Before And During The Covid-19 Pandemic

This research aims to analyze the financial performance of telecommunications sektor companies judging from profitability ratios which unclude ROA, ROE, and NPM period before and during the Covid-19 pandemi. Covid-19 has an impact on the weakening of various sektors of the economy. Nevertheless, there are still some sektors that are able togrow. One of them is the telecommunications sektor. The internet plays a big role in community activities that are generally carried out online, causing an increase in the performance of telecommuniciation issuers. The data used in this study is the financial statements of telecommunication companies listed on the Indonesia Stock Exchange quarter 2 of 2019-quarter 1 of 2021 and analyzed using descriptive methods. The results showed that the financial performance of telecommunications sektor companies was guided by the average value of profitability ratios that include ROA, ROE, and NPM obtained results that during the covid-19 pandemi were first confirmed, overall, the average financial performance of telecommunications sektor companies has increased. Assesment with the analysis of Hotteling’s T2 test also provided results that there was no difference in financial performance in terms of the profitability ratio between before and during the covid-19 pandemi

Auditory Brainstem Response Detection Using Machine Learning: A Comparison With Statistical Detection Methods.

The primary objective of this study was to train and test machine learning algorithms to be able to detect accurately whether EEG data contains an auditory brainstem response (ABR) or not and recommend suitable machine learning methods. In addition, the performance of the best machine learning algorithm was compared with that of prominent statistical detection methods. Four machine learning algorithms were trained and evaluated using nested k-fold cross-validation: a random forest, a convolutional long short-term memory network, a stacked ensemble, and a multilayer perceptron. The best method was evaluated on a separate test set and compared with conventional detection methods: Fsp, Fmp, q-sample uniform scores test, and Hotelling's T2 test. The models were trained and tested on simulated data that were generated based on recorded ABRs collected from 12 normal-hearing participants and no-stimulus EEG data from 15 participants. Simulation allowed the ground truth of the data ("response present" or "response absent") to be known. The sensitivity of the best machine learning algorithm, a stacked ensemble, was significantly greater than that of the conventional detection methods evaluated. The stacked ensemble, evaluated using a bootstrap approach, consistently achieved a high and stable level of specificity across ensemble sizes. The stacked ensemble model presented was more effective than conventional statistical ABR detection methods and the alternative machine learning approaches tested. The stacked ensemble detection method may have potential both in automated ABR screening devices as well as in evoked potential software, assisting clinicians in making decisions regarding a patient's ABR threshold. Further assessment of the model's generalizability using a large cohort of subject recorded data, including participants of different ages and hearing status, is a recommended next step.

Perception of genital self-image, sexual quality of life and marital adjustment in infertile women

This study was conducted to determine the perception of genital self-image, sexual quality of life and marital adjustment in infertile women. The sample of this descriptive study consisted of 135 infertile women who applied to a university hospital in a provincial center in the east of Turkey between November 2020-January 2021. Data were collected using Personal Information Form, Female Genital Self-Image Scale (FGSIS),Marital Adjustment Test (MAT) and Sexual Quality of Life Questionnaire-Female (SQoL-F). Data analysis was performed using descriptive statistics, independent-samples t-test, one-way analysis of variance(ANOVA), Kruskal-Wallis test, Tamhane’s T2 test, and Pearson’s correlation analysis. FGSIS, SQoL-F, and MAT were found at moderate levels in the women who participated in the study (17.99 ± 4.87, 65.58 ± 26.77, 37.77 ± 14.16, respectively). There was a moderate positive correlation between the total scores of FGSIS and SQoL-F, and a moderate and weak positive correlation between FGSIS and MAT and its sub-dimensions (p < 0.01).A moderate and weak positive correlation was found between SQoL-F and MAT and its sub-dimensions(p < 0.01).An increase in a positive genital self-image was associated with an increase in sexual life quality, marital adjustment, and agreement and positive relationship with the spouse. In addition, an increase in sexual quality of life was also associated with an increase in marital adjustment and agreement and positive relationship with the spouse. The vice versa could also be valid.

The effects of vitamin D, fish oil and exercise on cardiovascular parameters in ovariectomized rats

Abstract Objectives This study compared effects of vitamin D, fish oil and exercise on cardiovascular parameters in ovariectomized rats. Materials and methods This is an experimental study conducted with 45 female Wistar Albino rats; consisted of one sham (n=8) and four intervention (n=37) groups. Rats (n=37) were oophorectomized and, randomly divided into four groups at the end of the first week following wound healing. Interventions were applied to the groups of oophorectomize+Dvit, oophorectomize+fish oil and oophorectomize+exercise for 12 weeks. In analyzing the data, ANOVA and Tamhane’s T2 tests were used (p&lt;0.05). Results The levels of total-cholesterol (66.7 ± 7.6 mg/dL), HDL-cholesterol (33.8 ± 2.1 mg/dL), TOS (7.3 ± 1.2 μmol H2O2 Eq/L), TAS (4.0 ± 0.5 mmol Trolox Eq/L), OSI (0.2 ± 0.1) and total-cholesterol/HDL-cholesterol (2.0 ± 0.3) were obtained significant in exercising oophorectomized rats according to the oophorectomized rats (p&lt;0.05). The estrogen levels of rats using vitamin D and fish oil and exercising were found to be higher than those in menopause. Conclusions It was concluded that exercising oophorectomized rats had a lower risk of cardiovascular disease. In this context, exercise/physical activity should be recommended and must be supported for practicing in order to protect the cardiovascular health of postmenopausal women.

A key performance indicator-based fault detection scheme for marine diesel turbocharging systems

In this paper, a thermodynamic mechanism-based key performance indicator (KPI) construction is proposed for the diesel engine turbocharging system, upon which the corresponding fault detection scheme is studied. To be specific, the efficiency of the turbocharger is first selected as the KPI and constructed by the thermodynamic mechanism. Based on this, the relation between the KPI and the measurable correlated variables is built as the KPI-related model. Then, the subspace identification approach is applied to identify the established model. By applying T2 test statistic on the residual of the KPI-related model, a fault detection scheme is presented for system monitoring. Finally, the effectiveness of the proposed scheme is demonstrated on a simulation of the real turbocharger in the large ocean-going bulk carrier.

A comparison of the school engagement levels of science high school students who do sports and not do sports

The present study aimed to compare the school engagement levels of science high school students who do sports and do not do sports. The descriptive survey model was employed in the study. A total of 908 student’s volunteers studying in three High School in Izmit district of Kocaeli participated in the study. The “School Engagement Scale”, which was developed by Arastaman (2006) and confirmed in terms of validity and reliability, was used for this purpose. After calculating the frequency and percentage values of the data obtained from the school engagement scale, Independent Sample t-test and ANOVA test were applied, and post-hoc tests including the Bonferroni test and Tamhane’s T2 test were used according to the variance analysis test. The significance level was taken as 0.05. It was determined at the end of the study that while the mean school engagement levels varied significantly depending on the variables of school, gender, year level, economic status and engagement in a sport branch, it did not differ significantly in terms of parental status and number of siblings. The general scale sub-dimension mean values of the variable of doing sports showed that the school engagement level of those who did sports were higher than those who did not. By determining the effect of sports activities on school engagement, the student's engagement to the school can be increased.

Controlling test specificity for auditory evoked response detection using a frequency domain bootstrap

BackgroundStatistical detection methods are routinely used to automate auditory evoked response (AER) detection and assist clinicians with AER measurements. However, many of these methods are built around statistical assumptions that can be violated for AER data, potentially resulting in reduced or unpredictable test performances. This study explores a frequency domain bootstrap (FDB) and some FDB modifications to preserve test performance in serially correlated non-stationary data. MethodThe FDB aims to generate many surrogate recordings, all with similar serial correlation as the original recording being analysed. Analysing the surrogates with the detection method then gives a distribution of values that can be used for inference. A potential limitation of the conventional FDB is the assumption of stationary data with a smooth power spectral density (PSD) function, which is addressed through two modifications. Comparisons with existing methodsThe FDB was compared to a conventional parametric approach and two modified FDB approaches that aim to account for heteroskedasticity and non-smooth PSD functions. Hotelling’s T2 (HT2) test applied to auditory brainstem responses was the test case. ResultsWhen using conventional HT2, false-positive rates deviated significantly from the nominal alpha-levels due to serial correlation. The false-positive rates of the modified FDB were consistently closer to the nominal alpha-levels, especially when data was strongly heteroskedastic or the underlying PSD function was not smooth due to e.g. power lines noise. ConclusionThe FDB and its modifications provide accurate, recording-dependent approximations of null distributions, and an improved control of false-positive rates relative to parametric inference for auditory brainstem response detection.

An overview of tests on high-dimensional means

Testing high-dimensional means has many applications in scientific research. For instance, it is of great interest to test whether there is a difference of gene expressions between control and treatment groups in genetic studies. This can be formulated as a two-sample mean testing problem. However, the Hotelling T2 test statistic for the two-sample mean problem is no longer well defined due to singularity of the sample covariance matrix when the sample size is less than the dimension of data. Over the last two decades, the high-dimensional mean testing problem has received considerable attentions in the literature. This paper provides a selective overview of existing testing procedures in the literature. We focus on the motivation of the testing procedures, the insights into how to construct the test statistics and the connections, and comparisons of different methods.

Moderate alcohol consumption and carotid intima-media thickness in type 2 diabetes.

Carotid intima-media thickness (IMT) is a risk predictor for myocardial infarction and stroke. Patients with type 2 diabetes mellitus are at higher risk for such conditions. The association of alcohol consumption with IMT is still controversial. We undertook a cross-sectional study of patients hospitalized in the Department of Endocrinology at Zhoushan Hospital from January 1st, 2013 to December 31st, 2015. Patients with a past medical history of cerebrovascular events, acute myocardial ischemia or unable to provide a detailed alcohol consumption history were excluded. Carotid IMT, together with blood biochemical examinations were collected. Data were analyzed using least significant difference t test, Tamhane's T2 test, Levene test, χ2-test and binary logistic regression model. 281 patients were enrolled in the study. The number of patients with elevated carotid IMT in moderate alcohol consumers was apparently less than alcohol non/heavy-consumers. In addition, the number of participants with elevated carotid IMT in liqueur consumers was higher than alcohol non-consumers and rice wine/beer consumers. Systolic blood pressure, C-reactive protein, glycosylated hemoglobin, low density lipoprotein cholesterol, triglyceride, gamma glutamyl transpeptidase, uric acid, cholesterol and creatinine levels were higher in elevated IMT patients, while high density lipoprotein cholesterol level was levels were significantly lower (p value<0.05). Moderate alcohol consumption has a protective effect on atherosclerosis in patients with type 2 diabetes mellitus, requiring consideration to dietary intake and physical activity, among other influences. Inflammation theory and lipid metabolism could be involved in such prophylaxis effects.

The Ranking Function for Solving the Fuzzy Hotelling T2 Test

A multivariate control chart is measured by many variables that are correlated in production, using the quality characteristics in any product. In this paper, statistical procedures were employed to find the multivariate quality control chart by utilizing fuzzy Hotelling test. The procedure utilizes the triangular membership function to treat the real data, which were collected from Baghdad Soft Drinks Company in Iraq. The quality of production was evaluated by using a new method of the ranking function.

The Effect Of Koya Reboned Powder Consumption On Protein Levels Of Pregnant Women In Prevention Of Stunting In Babies

Linear growth retardation in childhood has decreased over the past few decades, but has not had a positive effect. In Indonesia, the change in the prevalence of stunting is around 37%. The nutritional status of pregnant women plays an important role in the incidence of stunting, which will be seen at the age of &lt;5 years in 1000 days of their life. Pregnant women with poor nutrition and significant infection can give birth to a baby with stunting. For this reason, nutritional intake is needed, one of the animal foods that are high in protein is rebon shrimp about 62.4 g / 100 grams of dried shrimp. Protein has an important component so it is necessary for the physical development of children. The purpose of this study was to analyze serum protein levels before and after consuming rebon shrimp based PMT powder in the intervention group and control group and to analyze differences in serum protein levels for pregnant women before and after consuming PMT Koya powder made from rebon shrimp between the control and intervention groups. . This type of research is a quantitative study with a quasi-experimental method using the pre post test control group design approach. The number of respondents was 30 people who were divided into 2 groups, namely the intervention group and the control group. The intervention group was given koya powder as much as 100 grams / day for 7 days, assuming the fulfillment of 70 KKal. Data analysis using Data analysis using the Mann-Whitney test, if the data is not normally distributed. If the data are not normally distributed using the free sample t2 test. The conclusion of the analysis results to answer the research hypothesis. The results of the study were significant values P 0.000 &lt;0.05. Conclusion There was a significant difference in serum protein levels of pregnant women before and after consuming PMT Koya powder made from boiled shrimp between the control and intervention groups.

Bioequivalence study of different brands of vildagliptin in healthy human subjects

BackgroundVildagliptin is a dipeptidyl peptidase-4 inhibitor used to treat diabetes mellitus. No bioequivalence study data have been published for the Indian population comparing bioequivalence of vildagliptin brands Galvus, Zomelis, and Jalra. This study aimed to evaluate the bioequivalence between three brands of vildagliptin 50 mg tablet (test 1, Zomelis; test 2, Jalra; and reference, Galvus) and to compare these test formulations with the reference formulation to meet the regulatory requirements of bioequivalence of CDSCO, India. The study was conducted in the clinical research center of the college after enrolling 12 healthy volunteers. This study was a single-dose, randomized, open-label, balanced, three treatment, three period, under fasting condition in 12 adult healthy volunteers. After overnight fasting, the subjects received a single dose of either of any three brands of the vildagliptin tablet (T1—test 1; T2—test 2; and R—reference). The washout period was 7 days. Randomization was in the way of T1T2R in the first period, T2T1R in the second period, and RT1T2 in the third period. Blood samples were collected, after that drug concentration in the plasma was measured with the help of HPLC. Outcome measures 90% confidence interval of the geometric mean ratios (test/reference) for the LnCmax, LnAUC0-t, and LnAUC0-∞ was calculated.ResultsThe AUC0-t was 1390.03, 1401.50, and 1409.37 ng h/ml for the T1, T2, and R, respectively. Cmax was 287.89, 287.41, and 285.17 ng/ml for the T1, T2, and R, respectively. AUC0-∞ was 1452.03, 1467.59, and 1473.53 ng h/ml for the T1, T2, and R, respectively. No significant difference was observed in the pharmacokinetic parameters between the T1, T2, and R. The geometric mean ratios for T1/R for LnCmax, LnAUC0-t, and LnAUC0-∞ were 1.0014 (90% CI, 1.0002–1.0026), 0.9992 (90% CI, 0.9971–1.0013), and 0.9994 (90% CI, 0.9973–1.0016), respectively. For the T2/R, geometric mean ratios for LnCmax, LnAUC0-t, and LnAUC0-∞ were 1.0003 (90% CI, 0.9992–1.0013), 0.9988 (90% CI, 0.9969–1.0008), and 0.9985 (90% CI, 0.9961–1.0010), respectively.ConclusionIn this single-dose study involving Indian healthy volunteers under fasting conditions, the three brands of vildagliptin (Zomelis, Jalra, and Galvus) were bioequivalent as per the bioequivalence criterion of CDSCO, India.

IN VITRO COMPARISON OF CYCLIC FATIGUE RESISTANCE OF PROTAPER NEXT AND TRUSHAPE 3D CONFORMING FILE NICKEL-TITANIUM ROTARY INSTRUMENTS

Aim: The purpose of this study was to compare the cyclic fatigue resistance of all instruments of the ProTaper Next (PTN) and TRUShape 3D Conforming File (TRS) systems. Materials and Methods: A total of 120 nickel–titanium rotary instruments were divided into eight groups: PTN X1, PTN X2, PTN X3, PTN X4, TRS 20/.06v, TRS 25/.06v, TRS 30/.06v and TRS 40/.06v. Each group had 15 instruments. All the instruments were tested for cyclic fatigue resistance in stainless steel artificial canals with 5 mm radius and 60° angle of curvature. They were rotated until they got fractured, and the test was performed in a saline solution at 35°C (±2). The number of cycles to fracture (NCF) was calculated by measuring the time to fracture. The NCF data were analysed statistically using the Kruskal–Wallis H and post hoc Tamhane T2 tests for multiple comparisons (α-level = 0.05). Results: The PTN X1 group had the highest NCF (P < 0.05). There was no statistically significant difference between the X2 and TRS 25/.06 groups (P > 0.05). However, there was a statistical difference between the other groups of similar sizes (X1–TRS 20/.06v) (X3–TRS 30/.06v) (X4–TRS 40/.06v) (P < 0.05). Conclusion: Within the limitations of this study, most of the PTN instruments (X1, X3, and X4) have better cyclic fatigue resistance than do TRS instruments (20/.06, 30/.06 and 40/.06) even if they were manufactured with older technology. This result showed that the S-curve design increases the risk of fracture in instruments with large tapers and tip sizes. Keywords: cyclic fatigue resistance, S-curve design, TRUShape ProTaper Next ve TRUShape 3D Conforming File Nikel-Titanyum Döner Aletlerinin Döngüsel Yorulma Dirençlerinin İn Vitro Olarak Karşılaştırılması ÖZ Amaç: Bu çalışmanın amacı ProTaper Next (PTN) ve TRUShape 3D Conforming File (TRS) sistemlerindeki tüm döner aletlerin döngüsel yorulma dirençlerinin kıyaslanmasıdır. Gereç ve Yöntem: Toplam 120 nikel-titanyum döner alet 8 gruba bölündü: PTN X1, PTN X2, PTN X3, PTN X4, TRS 20/.06v, TRS 25/.06v, TRS 30/.06v and TRS 40/.06v. Her bir grupta 15 alet vardı. Tüm aletler 5 mm yarıçaplı ve 60 ° eğimli açıya sahip paslanmaz çelik yapay kanallarda döngüsel yorgunluk direnci açısından test edilmiştir. Aletler kırılana kadar döndürüldü ve test 35°C (±2) sıcaklıkta serum solüsyonu içinde gerçekleştirildi. Döngüsel Kırılma sayısı (DKS), kırılma zamanı ölçülerek hesaplandı. DKS verileri Kruskal–Wallis H testi ve post-hoc Tamhane T2 çoklu karşılaştırma testleri ile istatistiksel olarak analiz edildi (α-level = 0.05). Bulgular: PTN X1 grubu en yüksek DKS’ye sahipti (P < 0.05). PTN X2 and TRS 25/.06 grupları arasında istatistiksel açıdan bir fark yoktu (P > 0.05). Benzer boyutlara sahip diğer gruplar arasında ise istatistiksel olarak fark vardı (X1–TRS 20/.06v) (X3–TRS 30/.06v) (X4–TRS 40/.06v) (P < 0.05). Sonuç: Bu çalışmanın sınırları dahilinde, PTN döner aletlerinin bir kısmı (X1, X3 ve X4) daha eski bir teknoloji ile üretilmiş olmalarına ragmen, TRS döner aletlerinden (20/.06, 30/.06 ve 40/.06) daha yüksek döngüsel yorulma direncine sahiptir. Bu sonuç, S-eğimli tasarımın özellikle büyük konik ve uç boyutlarına sahip döner aletlerde kırılma riskini arttırdığını göstermiştir. Anahtar Kelimeler: döngüsel yorulma direnci, S-eğimli tasarım, TRUShape

Toxicity assessment of dimethyl carbonate following 28 days repeated inhalation exposure.

Dimethyl carbonate (DMC) has been used as a reagent in methylation reactions, can be used as paints, coatings, and adhesives, and is a chemical that is being used increasing, which poses a health hazard to workers who handle it. So, the toxic reactions of F344 rats with inhalation exposure to 600, 1600, and 5000 ppm concentrations for 6 hours, 5 days a week, 4 weeks was evaluated. During the exposure period, general signs were observed, body weight and food consumption were measured, and hematologic and blood biochemical tests, organ weight measurements, necropsy, and histopathological examination were performed after the end of exposure. During the exposure period, dimethyl carbonate was exposed to an average of 599.26±31.40, 1614.64±80.79 and 5106.83±297.13 ppm in the chambers of the T1, T2 and T3 test groups, respectively. During the test period, general signs, weight change, food consumption, organ weight measurement, necropsy, and histopathological examination did not show any effects related to exposure to the test substance. However, as a result of blood and blood biochemical tests, an increase in AST, ALP, APTT, and PT levels was observed. From these results, it is judged that liver is the target organ when repeated inhalation exposure of dimethyl carbonate, the test substance, for 4 weeks, and the exposure-related effects of the test substance were observed at PT and ALP levels up to 600 ppm exposure concentration, but NOEC (No Observed Effect Concentration) was determined to be less than 600 ppm because it was not judged as an adverse effect.