Effect of gallic acid addition on some mechanical properties of self-adhesive resin cements

Self-adhesive resin cements (RCs) activate matrix metalloproteinase (MMP) and cathepsin-related collagen degradation, and gallic acid (GA) inhibits the activity of both MMPs and cysteine cathepsins. The purpose of this study was to evaluate the setting time, biaxial flexural strength, and Vickers hardness of self-adhesive RCs after the addition of two different concentrations of GA. RelyX U200 (3M ESPE) and Panavia SA (Kuraray) were modified with 0.5 and 1 wt% GA. The setting time of five samples in each RC group was assessed using a thermocouple apparatus as described in the ISO 4049 test. Biaxial flexure strength was measured using a universal testing machine until failure. Vickers hardness was measured with three randomized indentations on the surface of each resin disc. RCs without GA were used as control. Data were analyzed using a one-way analysis of variance and Tukey’s HSD test (α = 0.05). The setting times ranged from 2.4 to 4.6 min for RelyX and from 4.9 to 6.0 min for Panavia. The biaxial flexure strength ranged from 76.5 to 109.7 MPa for RelyX and from 73.3 to 108.2 MPa for Panavia. Vickers hardness values ranged from 41.6 to 58.6 for RelyX and 27.2 to 33.6 for Panavia. The addition of 0.5 and 1 wt% GA to improve durability of resin-dentin bonds had no adverse effects on setting time, whereas the biaxial flexure strength and Vickers hardness values for the tested materials were significantly reduced.</p

Evaluation of nutritional status in pediatric intensive care unit patients: the results of a multicenter, prospective study in Turkey

IntroductionMalnutrition is defined as a pathological condition arising from deficient or imbalanced intake of nutritional elements. Factors such as increasing metabolic demands during the disease course in the hospitalized patients and inadequate calorie intake increase the risk of malnutrition. The aim of the present study is to evaluate nutritional status of patients admitted to pediatric intensive care units (PICU) in Turkey, examine the effect of nutrition on the treatment process and draw attention to the need for regulating nutritional support of patients while continuing existing therapies.Material and MethodIn this prospective multicenter study, the data was collected over a period of one month from PICUs participating in the PICU Nutrition Study Group in Turkey. Anthropometric data of the patients, calorie intake, 90-day mortality, need for mechanical ventilation, length of hospital stay and length of stay in intensive care unit were recorded and the relationship between these parameters was examined.ResultsOf the 614 patients included in the study, malnutrition was detected in 45.4% of the patients. Enteral feeding was initiated in 40.6% (n = 249) of the patients at day one upon admission to the intensive care unit. In the first 48 h, 86.82% (n = 533) of the patients achieved the target calorie intake, and 81.65% (n = 307) of the 376 patients remaining in the intensive care unit achieved the target calorie intake at the end of one week. The risk of mortality decreased with increasing upper mid-arm circumference and triceps skin fold thickness Z-score (OR = 0.871/0.894; p = 0.027/0.024). The risk of mortality was 2.723 times higher in patients who did not achieve the target calorie intake at first 48 h (p = 0.006) and the risk was 3.829 times higher in patients who did not achieve the target calorie intake at the end of one week (p = 0.001). The risk of mortality decreased with increasing triceps skin fold thickness Z-score (OR = 0.894; p = 0.024).ConclusionTimely and appropriate nutritional support in critically ill patients favorably affects the clinical course. The results of the present study suggest that mortality rate is higher in patients who fail to achieve the target calorie intake at first 48 h and day seven of admission to the intensive care unit. The risk of mortality decreases with increasing triceps skin fold thickness Z-score

3-D shear wave velocity structure beneath the European Side of Istanbul from seismic noise arrays analysis

It has been shown that during the 1999 August 17 Izmit earthquake local site effects affected ground motion in distant areas such as the damage observed in Avcilar, west of. Istanbul. Despite efforts to study soil conditions in Istanbul in recent years, site effect problems in the deeper soil are not completely defined. Besides this, the main problems expected in the city of. Istanbul will be the result of amplification of ground motion due to an earthquake. To understand these effects, studies were carried out which showed either limited measurements or provided data for shallow depth by obtaining only the depth of engineering bedrock or the average shear wave velocity down to 30 m depth (V-s30)

Bedrock Depth Mapping of the Coast South of Istanbul: Comparison of Analytical and Experimental Analyses

Local S-wave velocity-depth profiles and bedrock depth distribution are key factors in assessing seismic hazard and earthquake ground motion characteristics since they allow determination of the amplification potential of geological formations overlying bedrock. In this study, an empirical relationship between the thickness of Tertiary-Quaternary sediments (hereafter referred as cover) overlying Palaeozoic bedrock and their resonance frequencies was calculated for the Istanbul region and the bedrock depth distribution beneath the city was presented. The relationship was investigated by comparing transfer functions obtained from single station microtremor analyses and one-dimensional (1D) S-wave velocity profiles at sites where shallow velocity structure is known. Geotechnical data consisting of standard penetration test (SPT) blow counts and standard soil descriptions were evaluated from 15 boring sites and microtremor measurements were carried out. The bedrock depth of each site was determined by computing analytical transfer functions to fit the resonance frequency and the shape of experimental transfer functions. Based on those results, a relationship between the resonance frequency and the thickness of the cover was derived. Finally, the bedrock distribution beneath populated areas of Istanbul was obtained by applying the derived relationship to 86 strong-motion sites, where the resonance frequencies are known

V(S)30, site amplifications and some comparisons: The Adapazari (Turkey) case

The aim of this study was to investigate the role of V(S)30 in site amplifications in the Adapazari region, Turkey. To fulfil this aim, amplifications from V(S)30 measurements were compared with earthquake data for different soil types in the seismic design codes. The Adapazari area was selected as the study area, and shear-wave velocity distribution was obtained by the multichannel analysis of surface waves (MASWs) method at 100 sites for the top 50 m of soil. Aftershock data following the Mw 7.4 Izmit earthquake of 17 August 1999 gave magnitudes between 4.0 and 5.6 at six stations installed in and around the Adapazari Basin, at Babali, Seker, Genc, Hastane, Toyota and Imar. This data was used to estimate site amplifications by the reference-station method. In addition, the fundamental periods of the station sites were estimated by the single station method. Site classifications based on V(S)30 in the seismic design codes were compared with the fundamental periods and amplification values. It was found that site amplifications (from earthquake data) and relevant spectra (from V(S)30) are not in good agreement for soils in Adapazari (Turkey). (c) 2013 Elsevier Ltd. All rights reserved

A study on warning algorithms for Istanbul earthquake early warning system

17 August (Mw 7.4) and 12 November 1999 (Mw 7.2) earthquakes have caused major concern about future earthquake occurrences in Istanbul and in the Marmara Region. Stress transfer studies and renewal model type probabilistic investigations indicate about 2% annual probability for a M(w) = 7+ earthquake in the Marmara Sea. As part of the preparations for the expected earthquake in Istanbul, an early warning system has been established in 2002. A simple and robust algorithm, based on the exceedance of specified threshold time domain amplitude and the cumulative absolute velocity (CAV) levels, is implemented for this system. Rational threshold levels related to new bracketed CAV window approach (BCAV-W) are determined, based on dataset of strong ground motion records with fault distances of less than 100 km, as 0.2 m/s, 0.4 m/s and 0.7 m/s related to three alarm levels which will be incorporated in the Istanbul earthquake early warning system. Citation: Alcik, H., O. Ozel, N. Apaydin, and M. Erdik (2009), A study on warning algorithms for Istanbul earthquake early warning system, Geophys. Res. Lett., 36, L00B05, doi:10.1029/2008GL036659

Morphologic and seismic evidence of rapid submergence offshore Cide-Sinop in the southern Black Sea shelf

Multi-beam bathymetric and multi-channel seismic reflection data obtained offshore Cide-Sinop have revealed important records on the latest transgression of the Black Sea for the first time. A relatively large shelf plain within the narrow southern continental shelf characterized by a flat seafloor morphology at -100 water depth followed by a steep continental slope leading to -500 m depth. This area is widely covered by submerged morphological features such as dunes, lagoons, possible aeolianites, an eroded anticline and small channels that developed by aeolian and fluvial processes. These morphological features sit upon an erosional surface that truncates the top of all seismic units and constitutes the seafloor over the whole shelf. The recent prograded delta deposits around the shelf break are also truncated by the similar erosional surface. These results indicate that offshore Cide-Sinop was once a terrestrial landscape that was then submerged. The interpreted paleoshoreline varies from -100 to -120 m. This variation can be explained by not only sea level changes but also the active faults observed on the seismic section. The effective protection of morphological features on the seafloor is the evidence of abrupt submergence rather than gradual. In addition, the absence of coastal onlaps suggests that these morphological features should have developed at low sea level before the latest sea level rise in the Black Sea. (C) 2018 Elsevier B.V. All rights reserved