Entropy in Born-Infeld gravity

There is a class of higher derivative gravity theories that are in some sense natural extensions of cosmological Einstein's gravity with a unique maximally symmetric classical vacuum and only a massless spin-2 excitation about the vacuum and no other perturbative modes. These theories are of the Born-Infeld determinant form. We show that the macroscopic dynamical entropy as defined by Wald for bifurcate Killing horizons in these theories are equivalent to the geometric Bekenstein-Hawking entropy (or more properly Gibbons-Hawking entropy for the case of de Sitter spacetime) but given with an effective gravitational constant which encodes all the information about the background spacetime and the underlying theory. We also show that the higher curvature terms increase the entropy. We carry out the computations in generic n dimensions including the particularly interesting limits of three, four and infinite number of dimensions. We also give a preliminary discussion about the black hole entropy in generic dimensions for the Born-Infeld theories

A case of bilateral spontaneous pneumothorax in a patient with covid-19 pneumonia

One of the rare complications of coronavirus disease-2019 (COVID-19), which can present with different clinical pictures, is pneumothorax. In our case, a patient who did not have predisposing risk factors for pneumothorax such as a history of trauma, smoking, past intubations, asthma, chronic obstructive pulmonary disease, and who developed bilateral spontaneous pneumothorax while under treatment with the diagnosis of COVID-19 is presented. Acute worsening in COVID-19 patients may be due to primary disease or pulmonary embolism. With this case, we emphasize the importance of considering spontaneous pneumothorax in patients with acute clinical deterioration

Choroidal vascularity index and retinal nerve fiber layer reflectivity in newly diagnosed migraine patients

Purpose: To evaluate the choroidal structural parameters, peripapillary retinal nerve fiber layer (RNFL) thickness, and optic density index (ODI) and their correlations in patients with migraine. Methods: Twenty-eight newly diagnosed migraine patients and 28 age-matched healthy controls were included in this prospective cross-sectional study. The enhanced depth-optical coherence tomography images were evaluated. The choroidal area (CA) was binarized to the luminal area (LA) and stromal area (SA) using Image J. The choroidal vascularity index (CVI), the mean peripapillary RNFL thickness, superior-inferior-nasal-temporal quadrant RNFL thicknesses, and the ODI were compared statistically. Results: The difference in the mean CVI between the patient group and controls reached a statistical significance (p=0.035). The mean RNFL thickness was significantly decreased in patients with migraine compared with the controls (p=0.040). The mean RNFL thickness in the superior, temporal, and inferior quadrants was significantly decreased in the patient group in comparison to the control subjects (p=0.030, p=0.001, and p=0.022, respectively). There were no significant differences between the migraine group and the controls for the mean ODI of RNFL (p=0.399). Conclusion: The CVI and the RNFL thickness except for the nasal quadrant were significantly decreased in newly diagnosed migraine patients. © 2021 Elsevier B.V

Studies on the reproductive effects of chronic treatment with agomelatine in the rat

Agomelatine is an antidepressant with a novel mechanism of action. It is a melatonergic agonist for MT1 and MT2 receptors and a serotonin (5-HT2C) receptor antagonist. Agomelatine has been suggested not to have adverse effects on sexual functions. However, the effects of chronic agomelatine administration on reproductive functions have not been sufficiently studied in animal models. We mainly aimed to explore the effects of agomelatine on reproductive functions in the male and female rats. For the experimental studies, Sprague Dawley rats were used. The animals started to receive daily oral agomelatine (10mg/kg) on post-natal day 21. Agomelatine advanced vaginal opening in the female rats whereas it delayed puberty onset in the male rats. Agomelatine treatment significantly decreased intromission frequencies, which indicates a facilitator role of this antidepressant on male sexual behavior. In the forced swimming test (FST) used for assessing antidepressant efficacy, agomelatine induced a significant decrease in duration of immobility, and an increase in the swimming time, respectively, which confirms the antidepressant-like activity of agomelatine. The present findings suggest that agomelatine shows a strong antidepressant effect in the male rats without any adverse influences on sexual behavior, and its effects on pubertal maturation seem to show sex-dependent differences.TÜBiTAK – 113S19

Investigation of mechanical and printing properties of Poly(Lactic acid) and composite filaments used in 3D printers

Bu çalışmada, 3 boyutlu (3B) yazıcılarda kullanımı gün geçtikçe artan poli(laktik asit) (PLA) ve kompozit filamentlerinin mekanik ve baskı özelliklerini etkileyen bazı çevresel şartlar incelenmiştir. Filament olarak PLA, PLA/Grafit ve PLA/polihidroksibütirat (PHB) kompozit filamentler kullanılmıştır. Çevresel şartlar olarak 25 °C sıcaklıktaki su ve %80 bağıl nemli ortam seçilmiştir. Filamentler 5, 10, 15, 20 gün süreler ile bu ortamlara maruz bırakılmış, daha sonra bu filamentlerden standart kemik numuneler basılmıştır. Filamentler ve basılan numunelere çekme testi uygulanmış, fourier dönüşümlü kızıl ötesi spektrometresi (FTIR) analizleri yapılmış, numune yüzeylerinin yüzey pürüzlülükleri ölçülmüş ve kırılma yüzeylerinin taramalı elektron mikroskopu (SEM) görüntüleri alınmıştır. Yapılan deneyler sonucunda çevresel şartlara maruz kalmış PLA, PLA/Grafit kompozit filamentlerden yapılan 3B baskılarda baskı kalitelerinin ve çekme dayanımlarının azaldığı görülmüştür. Nemli ortama maruz kalan PLA/PHB kompozit filamentte ise baskı kalitesi ve çekme dayanımının arttığı görülmüştür.In this study, some environmental conditions affecting the mechanical and printing properties of poly(lactic acid) (PLA) and composite filaments, which are increasingly used in 3 dimensional (3D) printers, were investigated. PLA, PLA/Graphite and PLA/polyhydroxybutyrate (PHB) composite filaments were used. Water at 25 °C and 80% relative humidity were chosen as environmental conditions. The filaments were exposed to these environments for 5, 10, 15, 20 days and then standard dog-bone samples were printed from these filaments. Tensile test was applied to filaments and printed samples, fourier transform infrared spectroscopy (FTIR) analyzes were made, surface roughness of sample surfaces were measured and scanning electron microscopes (SEM) images of fracture surfaces were taken. As a result of the experiments, it was observed that the print quality and tensile strength of 3D prints made from PLA, PLA/Graphite composite filaments that were exposed to environmental conditions decreased. It was observed that the print quality and tensile strength increased in PLA/PHB composite filament exposed to humid environment

Evaluation of self-adhering flowable composites on repeated bracket bonding process: An in vitro study

WOS:000920098500003Duration of orthodontic treatment becomes major concern. The present study compared shear bond strength (SBS) and adhesive remnant index (ARI) values of different adhesive systems with different application methods on rebonding process of retrieved orthodontic brackets. Eighty premolar teeth were equally divided into five groups. Transbond XT (TXT) which belongs to total-etch system was used in Group 1 as the control group. Nova Compo-SF (NC) and Vertise Flow (VF) (Kerr Dental, Italy) which are self-adhering flowable composites were used in Group 2 (NC+etch) and Group 3 (VF+etch) respectively with additional etching before application. Group 4 (NC) and Group 5 (VF) were used by following instructions of each brand. The brackets were debonded with a bracket removing plier and rebonded with the same procedures after sandblasting of the bracket and surface cleaning of the enamel. SBS and ARI were measured for each sample. Comparison between all groups was performed by Kruskal-Wallis test and chi-square test. The highest SBS was observed in NC+etch (median = 11.44, mean = 13.49±9.42), followed by NC (median = 10.17, mean = 11.35±6.55), TXT (median = 6.36, mean = 8.06±6.33), VF+etch (median = 5.68, mean = 6.75±4.58), and VF (median = 2.62, mean = 2.92±2.57), respectively. ARI 1 was observed in 81.3% of TXT whereas 62.5% of NC+etch. ARI 1, 2, and 3 were equally distributed in VF+etch group (31.3%). ARI 5 was observed in 37.5% of NC and 62.5% of VF. Analyses referred to statistically significant differences between five groups regarding both SBS and ARI (p < 0.001). As NC showed the highest SBS on rebonding process, it can be a promising alternative to TXT which is the gold standard. © Penerbit Universiti Sains Malaysia. 2022 This work is licensed under the terms of the Creative Commons Attribution (CC BY) (http://creativecommons.org/licenses/by/4.0/). All Rights Reserved

A novel method for measuring tooth angulation in permanent mandibular second molars with delayed tooth eruption

PMID: 33855891Objective: To investigate the effect of angulation of permanent mandibular second molars (MM2) on eruption problems and investigate a new method of measuring MM2 angulation for the diagnosis and evaluation of delayed tooth eruption (DTE) for easy use in dental practice. Design: Retrospective study. Setting: Department of Orthodontics, Necmettin Erbakan University. Participants: A total of 98 patients aged 9-18 years. Methods: Patients with 64 permanent MM2s with delayed eruption problems were included in the study group. The control group consisted of patients with 83 normally erupted teeth. In addition, a sub-group, consisting of 23 patients showing unilaterally delayed eruption of the same teeth, was set as a split-mouth group. All patients with unilateral delayed eruption of second molar teeth were selected from the study group to form the sub-group. Angulations of permanent MM2s were measured on panoramic radiographs with two measurement methods: (1) a new method; and (2) a previously accepted method. The comparison of the study and control groups was performed by Mann-Whitney U-test and the split-mouth group was analysed with the paired t-test. The P value was set at 0.05 for statistical significance. Results: Measurements of the tooth angulation values of the study group were significantly higher than in the control group for both measurement methods (P < 0.001). In addition, in the split-mouth group, angulation values of delayed eruption side were significantly higher than the erupted side (P < 0.001). Conclusion: Increased angulations of permanent MM2s could be associated with delayed eruption problems of these teeth. This new method could be useful in clinical dentistry to determine the eruption evaluation of lower second molars

Interpretation of m.3243A>G in mtDNA in Clinical Expressivity Versus Tissue Heteroplasmy Ratios with Text Mining Analysis

Introduction: MELAS (mitochondrial-encephalomyopathy, lactic-acidosis, and stroke-like episodes) ismultisystem disorder, typically presented between the ages of two to 40 years, associated with pathogenicmtDNA variants. Approximately 80% of the patients present with m.3243A&gt;G of MT-TL1 encodingmitochondrial tRNA-leucine1 (UUA/G). Clinical variability basically attributed to the mutation load in tissues.Material and method: 319 articles published on m.3243 A&gt;G, between the years of 1995-2018, are investigatedfor the number of cases attributed with age of definitive diagnosis, gender, inheritance, clinical and biochemicalspectrum and tissue distribution of the heteroplasmic ratios. Data recorded on spread-sheets, extracted to chartsby using Vim text editor, statistical analysis performed with Python. Results: 468 out of 730 total reportedatients’ data with heter lasmy revealed. 42,9% had my athies (201/468), 30.8% had ne r l gi alsymptoms (144/468), 16.7% had cardiovascular (78/468), 11% had ear/eye problems (53/468), and 4.1% hadgastrointestinal complications. Methods of heteroplasmy measurements differed in reports. Clinical groupsunder additional findings of either with hearing loss, ocular abnormalities and endocrinological problems, 48with 73.6±13.6%, 19 with 63.2±19.6% and 18 with 61.7±20.8% m tati n l ads were al lated. s le andbl d meas rements in 79 atients were 63.6±19.3% and 25.7±19.3%, res e tively. Similarly, 17 atients’rati s were re rted r rine and bl d, 55.9±21% and 20.7±10.4%, res e tively. Discussion: Leukocytes arethe major tissue used in diagnosis, nevertheless has lower accuracy. Urine was as valuable as muscle forobtaining threshold values, moreover convenient since non-invasive. Majority of the m.3243A&gt;G variant ofmtDNA was associated with myopathic findings and least with episodic vomiting