Quasi Periodic Oscillations (QPOs) and frequencies in an accretion disk and comparison with the numerical results from non-rotating black hole computed by the GRH code

The shocked wave created on the accretion disk after different physical phenomena (accretion flows with pressure gradients, star-disk interaction etc.) may be responsible observed Quasi Periodic Oscillations (QPOs) in $X-$ray binaries. We present the set of characteristics frequencies associated with accretion disk around the rotating and non-rotating black holes for one particle case. These persistent frequencies are results of the rotating pattern in an accretion disk. We compare the frequency's from two different numerical results for fluid flow around the non-rotating black hole with one particle case. The numerical results are taken from our papers Refs.\refcite{Donmez2} and \refcite{Donmez3} using fully general relativistic hydrodynamical code with non-selfgravitating disk. While the first numerical result has a relativistic tori around the black hole, the second one includes one-armed spiral shock wave produced from star-disk interaction. Some physical modes presented in the QPOs can be excited in numerical simulation of relativistic tori and spiral waves on the accretion disk. The results of these different dynamical structures on the accretion disk responsible for QPOs are discussed in detail.Comment: 13 figures, added reference, accepted for publication in Modern Physics Letters

Effects of protein deficiency on testosterone levels, semen quality and testicular histology in the developing male rat

The aim of the study was to evaluate the effects of protein deficiency on plasma testosterone levels, epididymal sperm characteristics and testicular histology in the developing male rat. Twenty four Wistar albino rats were used in the study and were fed with a diet variously containing 3 %, 10 % and 20 % protein. Plasma testosterone levels were significantly lower in rats fed 3 % protein when compared to rats fed 10 % and 20 % protein (P<0.05). Testicular weight in protein deficient rats (rats fed 3 % and 10 % protein) was significantly lower than that of a control group (20 % protein) (P<0.05). No sperm was present in the epididymal duct lumen, but germ cells were observed in some duct lumens in rats fed 3 % protein. Epididymal weight decreased significantly in rats fed 3 % protein compared to rats fed 10 % and 20 % protein (P<0.05). The results of this study clearly show that protein deficiency in developing male rats adversely affects gonadal endocrine function, testicular histology and spermatogenesis

Numerical simulation of small perturbation on an accretion disk due to the collision of a star with the disk near the black hole

In this paper, perturbations of an accretion disk by a star orbiting around a black hole are studied. We report on a numerical experiment, which has been carried out by using a parallel-machine code originally developed by D\"{o}nmez (2004). An initially steady state accretion disk near a non-rotating (Schwarzschild) black hole interacts with a "star", modeled as an initially circular region of increased density. Part of the disk is affected by the interaction. In some cases, a gap develops and shock wave propagates through the disk. We follow the evolution for order of one dynamical period and we show how the non-axisymetric density perturbation further evolves and moves downwards where the material of the disk and the star become eventually accreted onto the central body. When the star perturbs the steady state accretion disk, the disk around the black hole is destroyed by the effect of perturbation. The perturbed accretion disk creates a shock wave during the evolution and it loses angular momentum when the gas hits on the shock waves. Colliding gas with the shock wave is the one of the basic mechanism of emitting the $X-$rays in the accretion disk. The series of supernovae occurring in the inner disk could entirely destroy the disk in that region which leaves a more massive black hole behind, at the center of galaxies.Comment: 20pages, 8 figures, accepted for publication in Astrophysics and Space Scienc

Double cantilever indirect tension testing for fracture of quasibrittle materials

The Double Cantilever Beam (DCB) Mode I fracture testing has been widely used in fracture testing of especially fiber reinforced polymer composites and adhesive joints. Application of classical DCB testing to plain concrete or unreinforced ceramic specimens is not straightforward and cannot be carried out as in fiber reinforced polymer composites. Instead, an indirect tension approach is proposed in this study. Tests of notched geometrically similar DCB specimens made of normal and high strength concretes loaded eccentrically at the cantilever beam-column ends in compression have been carried out. Classical Type II size effect analyses of peak loads obtained from these tests are performed. The Microplane Model M7 is calibrated independently using uniaxial compression tests and employed to predict the peak loads of both tested and virtual geometrically similar DCB specimens. The same size effect analyses are performed on the predicted peak loads and the errors in the fracture parameters of the classical size effect analysis are determined.Peer ReviewedPostprint (author's final draft

Image acquisition effects on Unmanned Air Vehicle snow depth retrievals

Advancements in technology have facilitated new opportunities in aerial photogrammetry; one of these is the use of unmanned aerial vehicles (UAVs) to estimate snow depth (SD). Here, a multi-rotor type UAV is used for SD retrievals over an area of 172&thinsp;000&thinsp;m2. Photos with 80&thinsp;% forward and 60&thinsp;% side overlaps were taken by UAV on two different (snow-covered and snow-free) days. SD estimations were obtained from the difference between 3-D stereo digital surface models (DSMs) produced for both days. Manual SD measurements were performed on the ground concurrent with UAV flights. The current study is unique in that the SD retrievals were derived using two different image acquisition modes. In the first, images were taken as UAV was continuously flying and in the second UAV had small stops and kept its position in air fixed as the photos were taken. Root mean square error of UAV derived SDs is calculated as 2.43&thinsp;cm in continuous and 1.79&thinsp;cm in fixed acquisitions. The results support the hypothesis, based on theoretical considerations, that fixed-position image acquisitions using multi-rotor platforms should enable more accurate SD estimates. It is further seen that, as SDs increased, the errors in SD calculations are reduced.</p

Cervical Vertebral Anomalies in Patients With Transverse Maxillary Deficiency

Objective:The literature indicates a correlation between vertebral morphologic anomalies and some orthodontic malocclusions. The aim of this study was to examine the occurrence of the types of cervical vertebral anomalies (CVAs) in subjects with transverse maxillary deficiency (TMD) and to compare this with the occurrence of CVA in a control group without TMD.Materials and Method:A sample of 47 Turkish patients (17 boys, 30 girls) with TMD and another sample of 47 Turkish patients (15 boys, 32 girls) with adequate maxillary transversal dimensions was studied. A visual assessment of the cervical column was made using lateral cephalometric films. Characteristics of the cervical column were classified according to Sandham as fusions and posterior arch deficiencies of C1 (PADs). Clinically normal appearance was determined when the first 4 vertebrae could be traced as separate entities with all anatomic components present. Differences in occurrence of CVA between the groups and between genders were assessed by v2 independence test.Results:In the TMD group, 10,6% of the subjects had fusion in the cervical column, and 14,9% had PAD. In the control group, 17% of the subjects had fusion of the cervical column, and 8,5% had PAD. The occurrence of PAD was significantly increased in the TMD group (p,0.05), while no significant difference was found between the groups for occurrence of fusion (p.0.05). No statistically significant gender differences were found in the occurrence of CVA in the TMD group and the control group (p.0.05).Conclusion:No difference was found in the occurrence of fusion between the subjects with TMD and the subjects without TMD, and the occurrence of PAD was significantly increased in subjects with TMD

Reduced thermal expansion by surface-mounted nanoparticles in a pillared-layered metal-organic framework

Control of thermal expansion (TE) is important to improve material longevity in applications with repeated temperature changes or fluctuations. The TE behavior of metal-organic frameworks (MOFs) is increasingly well understood, while the impact of surface-mounted nanoparticles (NPs) on the TE properties of MOFs remains unexplored despite large promises of NP@MOF composites in catalysis and adsorbate diffusion control. Here we study the influence of surface-mounted platinum nanoparticles on the TE properties of Pt@MOF (Pt@Zn2(DP-bdc)2dabco; DP-bdc2-=2,5-dipropoxy-1,4-benzenedicarboxylate, dabco=1,4-diazabicyclo[2.2.2]octane). We show that TE is largely retained at low platinum loadings, while high loading results in significantly reduced TE at higher temperatures compared to the pure MOF. These findings support the chemical intuition that surface-mounted particles restrict deformation of the MOF support and suggest that composite materials exhibit superior TE properties thereby excluding thermal stress as limiting factor for their potential application in temperature swing processes or catalysis

Xanthones and Xanthone O\textit{O}‐β\textit{β}‐D‐Glucosides from the Roots of Polygala azizsancarii\textit{Polygala azizsancarii} Dönmez

Nine xanthone derivatives (1–9) were isolated from the roots of Polygala azizsancarii, which is a narrow endemic species for the flora of Türkiye. Based on all of the evidence, the structures of 1–9 were established as two previously undescribed xanthone O-glucosides, 3-O-β-D-glucopyranosyloxy-1,6-dihydroxy-2,5,7-trimethoxyxanthone (1), 3-O-β-D-glucopyranosyloxy-1,6-dihydroxy-2,7-dimethoxyxanthone (2), and seven previously described xanthones, 1,3,6-trihydroxy-2,5,7-trimethoxyxanthone (3), 1,3,6-trihydroxy-2,7-dimethoxyxanthone (4), 1,2,3,4,7-pentamethoxyxanthone (5), 1,3-dihydroxy-2,5,6,7-tetramethoxyxanthone (6), 1,3-dihydroxy-4,7-dimethoxyxanthone (7), 1,7-dihydroxy-3-methoxyxanthone (8), and 1,7-dihydroxy-2,3-methylenedioxyxanthone (9). The structures of the compounds were determined by spectroscopic methods, including 1D-NMR (1H-NMR, 13C-NMR, DEPT-135), 2D-NMR (COSY, NOESY, HSQC, HMBC, INADEQUATE), and HR-MS. The solid-state structures of 1–4, including the absolute configurations of the stereogenic carbons of the sugar moiety in 1 and 2, were established by X-ray crystal-structure analyses. For the newly described compounds, the trivial names sancarosides A (1) and B (2) are proposed

Does Whole Body Vibration Restore Immobilization-Induced Suppression in AMPK Activation

Objective: AMP activated kinase (AMPK) is involved in mitochondrial biogenesis, glucose transport and stimulates free fatty acid oxidation. Physical inactivity has been shown to increase incidence of metabolic diseases by decreasing the phosphorylation of AMPK. On the other hand, activation of AMPK via exercise training results in the reduction of insulin resistance. Currently, whole body vibration (WBV) is widely used to improve health, and has been proven to be effective to increase bone mineral density and muscle strength. Inactivity is inevitable especially during long-term bed rest or following sports injuries, and WBV may be an alternative strategy to improve muscle fitness and metabolic conditions. Therefore, this study aimed to elucidate the effects of WBV on AMPK, which plays an important role for cellular energy balance. Materials and Methods: 30 Wistar rats were assigned to one of the following groups (n=6 per group): Control (C), Immobilization (I), Immobilization+Remobilization (İR), Immobilization+WBV (IV), WBV (V). Immobilization was obtained through two weeks of bilateral leg casting. V groups underwent one week of 45Hz, 3mm Amp, 20min/day WBV. Animals in IR group underwent one week of remobilization following immobilization and animals in IV group underwent one week of WBV treatment during remobilization period following the initial two weeks of immobilization. At the end of the experimental procedure, soleus muscles were isolated, and mRNA, AMPK and p-AMPK levels were determined. Results: There were no differences in mRNA levels among groups. On the other hand, p-AMPK/AMPK ratio significantly decreased after two weeks of immobilization (