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result(s) for
"Celik, Alper"
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What Changed in Post-Earthquake Reinforced Concrete Damage in Türkiye? A Comparative Study from 1992 (Erzincan) to 2023 (Malatya)
by
Turan, Ahmet İhsan
,
Çelik, Alper
in
1992 Erzincan earthquake
,
2023 Kahramanmaraş earthquakes
,
Beam-columns
2026
This study presents a damage-based comparative assessment of reinforced concrete buildings affected by the 1992 Erzincan earthquake (Mw 6.8) and the 2023 Kahramanmaraş earthquake sequence (Pazarcık, Mw 7.7; Elbistan, Mw 7.6), two destructive earthquake events in Türkiye separated by nearly three decades. A distinctive contribution of the study is the presentation of original color photographs from the 1992 Erzincan earthquake, systematically documented and comparatively evaluated for the first time and directly compared with post-earthquake field observations from Malatya following the 2023 earthquake sequence. To complement the field-based evidence, representative strong ground motion records from both earthquake events were processed and compared using standard seismic intensity and spectral response parameters. The spectral evaluation indicates that the 1992 Erzincan ground motion and the 2023 Elbistan-related motion recorded in Malatya imposed comparable seismic demands relevant to typical reinforced concrete buildings, thereby providing a rational basis for cross-event damage interpretation. Despite substantial advances in Turkish seismic design codes, recurrent damage mechanisms were observed in both building stocks, particularly soft-story formation, short-column effects, inadequate transverse reinforcement, poor beam–column joint performance, and deficiencies in material quality and detailing. The findings demonstrate that seismic safety cannot be improved through code development alone unless design provisions are consistently translated into construction quality, detailing practice, inspection, and field implementation.
Journal Article
General decapping activators target different subsets of inefficiently translated mRNAs
by
He, Feng
,
Wu, Chan
,
Jacobson, Allan
in
Binding sites
,
Chromosomes and Gene Expression
,
Dcp1-Dcp2
2018
The Dcp1-Dcp2 decapping enzyme and the decapping activators Pat1, Dhh1, and Lsm1 regulate mRNA decapping, but their mechanistic integration is unknown. We analyzed the gene expression consequences of deleting PAT1, LSM1, or DHH1, or the DCP2 C-terminal domain, and found that: i) the Dcp2 C-terminal domain is an effector of both negative and positive regulation; ii) rather than being global activators of decapping, Pat1, Lsm1, and Dhh1 directly target specific subsets of yeast mRNAs and loss of the functions of each of these factors has substantial indirect consequences for genome-wide mRNA expression; and iii) transcripts targeted by Pat1, Lsm1, and Dhh1 exhibit only partial overlap, are generally translated inefficiently, and, as expected, are targeted to decapping-dependent decay. Our results define the roles of Pat1, Lsm1, and Dhh1 in decapping of general mRNAs and suggest that these factors may monitor mRNA translation and target unique features of individual mRNAs.
Journal Article
Seismic Performance and Nonlinear Flexural Behavior of Corroded Reinforced Concrete Columns: An Analytical and Parametric Study
2026
This study presents an analytical investigation and a parametric evaluation of the structural behavior and seismic performance of highly corroded reinforced concrete (RC) columns, based on previously conducted experimental studies by the authors. In the analytical phase, moment–curvature relationships were obtained by considering the deterioration of the mechanical properties of both concrete and reinforcing steel due to corrosion in RC column specimens. By linking the sectional moment–curvature response with the element-level behavior observed in the experimental program, the plastic hinge lengths and rotational capacities of the corroded RC columns were determined. Subsequently, a parametric study was carried out using the analytical framework developed in the first phase on a set of 48 RC column models. In this investigation, axial load ratio, concrete compressive strength, corrosion level, section type, and concrete cover depth were considered as key parameters. The results of the combined experimental and analytical investigations demonstrate that the adopted section analysis approach successfully captures the nonlinear flexural behavior observed in the corroded specimens and provides a reliable basis for evaluating the structural performance and for supporting the assessment of seismic performance of deteriorated RC columns.
Journal Article
Design deficiencies, failure modes and recommendations for strengthening in reinforced concrete structures exposed to the February 6, 2023 Kahramanmaraş Earthquakes (Mw 7.7 and Mw 7.6)
by
Kocaman, İrfan
,
Erbaş, Yaşar
,
Mercimek, Ömer
in
Civil Engineering
,
Columnar structure
,
Concrete
2025
After two major earthquakes centred in Kahramanmaraş on February 6, 2023, in Türkiye, there was significant destruction of the building stock. More than fifty thousand people lost their lives, and many people lost their comfort of life even though they were rescued from the wreckage. Researchers have emphasized that this catastrophic consequence is generally caused by design and production errors and low material quality in almost all building types, especially reinforced concrete, steel, masonry, and prefabricated structures. Within the scope of this study, damage patterns and the design flaws of reinforced concrete structures in Malatya, which is one of the provinces affected by the Kahramanmaraş earthquakes, were examined via a field study. During the fieldwork, it was determined that inadequate longitudinal reinforcement and stirrup reinforcement, in-depth reinforcement, and concrete quality, design errors in the column‒beam junction area, ignoring the structure‒soil interactions, short columns, torsional irregularity, and soft stories were the main factors that led reinforced concrete buildings to be heavily damaged or collapse. After the root causes of damage to reinforced concrete structures were examined, the measures and applications that should be taken to ensure that reinforced concrete structures can maintain their services in the event of earthquakes that are likely to occur in the future was discussed.
Journal Article
Variants in ASPH cause exertional heat illness and are associated with malignant hyperthermia susceptibility
2022
Exertional heat illness (EHI) and malignant hyperthermia (MH) are life threatening conditions associated with muscle breakdown in the setting of triggering factors including volatile anesthetics, exercise, and high environmental temperature. To identify new genetic variants that predispose to EHI and/or MH, we performed genomic sequencing on a cohort with EHI/MH and/or abnormal caffeine-halothane contracture test. In five individuals, we identified rare, pathogenic heterozygous variants in
ASPH
, a gene encoding junctin, a regulator of excitation-contraction coupling. We validated the pathogenicity of these variants using orthogonal pre-clinical models, CRISPR-edited C2C12 myotubes and transgenic zebrafish. In total, we demonstrate that
ASPH
variants represent a new cause of EHI and MH susceptibility.
The genetic cause(s) of malignant hyperthermia and exertional heat illness are unknown in approximately 30% of cases. To address this barrier, the authors performed genome sequencing on a large cohort of cases, identifying rare variants in
ASPH
, a gene encoding junctin, and validating them in animal and cell models.
Journal Article
Experimental Analysis of Rotor Blade Noise in Edgewise Turbulence
by
Rezgui, Djamel
,
Celik, Alper
,
Jamaluddin, Nur Syafiqah
in
Acoustics
,
Aerodynamic noise
,
Aerodynamics
2023
This paper presents an experimental investigation into the effects of turbulence ingestion on the aerodynamic noise characteristics of rotor blades in edgewise flight. A small-scaled, two-bladed rotor was used in the study. The test utilised two turbulence-generating grids, to generate turbulence inflows with different characteristics, and to compare them to the baseline configuration of the laminar inflow. The experiments were set at forwarding edgewise flight configuration, with freestream inflow velocity ranging from 10 m/s to 22 m/s. Simultaneous measurements of far-field acoustic pressure and load were conducted, along with a separate flow measurement using particle image velocimetry. The acoustic spectra demonstrated a larger contribution to the tonal noise radiation at blade passing frequency, and to the broadband noise radiation at the mid-frequency domain, due to turbulence ingestion. However, the broadband responses in the high-frequency domain were comparable between the tested laminar and turbulence inflow cases, with similar broadband humps featuring in the acoustic spectra. The directivity patterns of the overall sound pressure level showed that the noise radiation was lowest near the plane of rotation, and highest downstream. Turbulence ingestion effects could also be seen in the elevated noise levels throughout the observation positions for the grid inflow cases, particularly at larger advance ratios.
Journal Article
Low-Frequency-Noise Attenuation through Extended-Neck Double-Degree-of-Freedom Helmholtz Resonators
by
Celik, Alper
,
Gautam, Abhishek
,
Azarpeyvand, Mahdi
in
acoustic liner
,
Acoustic liners
,
Acoustics
2023
The use of acoustic liners, based on double-degree-of-freedom Helmholtz resonators, for low-frequency-noise attenuation is limited by the volume of individual resonating cavities. This study investigates the effect of the septum neck length on the acoustic performance of double-degree-of-freedom resonators, both experimentally and numerically, for varying cavity volume ratios. The underlying sound attenuation mechanism is studied by analysing the acoustic pressure fields within the resonator cavities. An increase in the septum neck is shown to lower the frequencies affected by the resonator. In addition, it deteriorates and significantly improves the sound attenuation performance at the primary and secondary peak transmission-loss frequencies, respectively.
Journal Article
Bariatric/Metabolic Surgery in the Asia-Pacific Region: APMBSS 2018 Survey
2019
IntroductionThe Asia-Pacific Metabolic and Bariatric Surgery Society (APMBSS) held its congress in Tokyo at the end of March, 2018, and representatives from Asia-Pacific countries presented the current status of bariatric/metabolic surgery in the “National Reports” session. The data are summarized here to show the current status and problems in the Asia-Pacific region in 2017.MethodsA questionnaire including data of 2016 and 2017 and consisting of eight general questions was prepared and sent to representatives in 18 Asia-Pacific countries by e-mail before the congress. After the congress, the data were analyzed and summarized.ResultsSeventeen of 18 countries responded to the survey. The frequency of obesity (BMI ≥ 30) in the 4 Gulf countries was > 30%, much higher than that in the other countries. In total, 1640 surgeons and 869 institutions were engaging in bariatric/metabolic surgery. In many East and Southeast Asian countries, the indication for bariatric surgery was BMI ≥ 35 or ≥ 37, whereas in many Gulf countries and Australia, it was BMI ≥ 40 or ≥ 35 with obesity-related disease. Ten of the 17 countries (58.8%) but only one of the 5 Southeast Asian countries (20.0%) had public health insurance coverage for bariatric surgery. In 2017, 95,125 patients underwent bariatric/metabolic surgery, with sleeve gastrectomy accounting for 68.0%, bypass surgery for 19.5%, and others for 12.5%. Current problems included public insurance coverage, training system, national registry, and lack of awareness and comprehension.ConclusionThis summary showed that bariatric/metabolic surgery is rapidly developing along with various problems in Asia-Pacific countries.
Journal Article
Natural history of a mouse model of X-linked myotubular myopathy
by
Pannia, Emanuela
,
Liang, Yijng
,
Volpatti, Jonathan
in
mice
,
muscle disease
,
myotubular myopathy
2022
X-linked myotubular myopathy (XLMTM) is a severe monogenetic disorder of the skeletal muscle. It is caused by loss-of-expression/function mutations in the myotubularin (MTM1) gene. Much of what is known about the disease, as well as the treatment strategies, has been uncovered through experimentation in pre-clinical models, particularly the Mtm1 gene knockout mouse line (Mtm1 KO). Despite this understanding, and the identification of potential therapies, much remains to be understood about XLMTM disease pathomechanisms, and about the normal functions of MTM1 in muscle development. To lay the groundwork for addressing these knowledge gaps, we performed a natural history study of Mtm1 KO mice. This included longitudinal comparative analyses of motor phenotype, transcriptome and proteome profiles, muscle structure and targeted molecular pathways. We identified age-associated changes in gene expression, mitochondrial function, myofiber size and key molecular markers, including DNM2. Importantly, some molecular and histopathologic changes preceded overt phenotypic changes, while others, such as triad structural alternations, occurred coincidentally with the presence of severe weakness. In total, this study provides a comprehensive longitudinal evaluation of the murine XLMTM disease process, and thus provides a critical framework for future investigations.
Journal Article
An Experimental and Numerical Study on the Effect of Spacing between Two Helmholtz Resonators
by
Celik, Alper
,
Gautam, Abhishek
,
Azarpeyvand, Mahdi
in
Acoustic impedance
,
Acoustics
,
Aircraft
2021
This study investigates the acoustic performance of a system of two Helmholtz resonators experimentally and numerically. The distance between the Helmholtz resonators was varied to assess its effect on the acoustic performance of the system quantitatively. Experiments were performed using an impedance tube with two instrumented Helmholtz resonators and several microphones along the impedance tube. The relation between the noise attenuation performance of the system and the distance between two resonators is presented in terms of the transmission loss, transmission coefficient, and change in the sound pressure level along the tube. The underlying mechanisms of the spacing effect are further elaborated by studying pressure and the particle velocity fields in the resonators obtained through finite element analysis. The results showed that there might exist an optimum resonators spacing for achieving maximum transmission loss. However, the maximum transmission loss is not accompanied by the broadest bandwidth of attenuation. The pressure field and the sound pressure level spectra of the pressure field inside the resonators showed that the maximum transmission loss is achieved when the resonators are spaced half wavelength of the associated resonance frequency wavelength and resonate in-phase. To achieve sound attenuation over a broad frequency bandwidth, a resonator spacing of a quarter of the wavelength is required, in which case the two resonators operate out-of-phase.
Journal Article