Search

Background. Doctors have higher rates of mental illness and suicide than the general population worldwide. Suicides of doctors are known to be underreported in developing countries. To the best of our knowledge, there are no studies investigating suicides among medical students and doctors in Turkey.Objectives. To investigate the characteristics of suicides in medical school students and doctors in Turkey.Materials and methods. In this retrospective study, newspaper websites and Google search engine were searched for information on medical school student and doctor suicides in Turkey between 2011 and 2021. Cases of suicide attempt, parasuicide or deliberate self-harm were not included in the study.Results. Sixty-one suicides were reported between 2011-2021. There was a male predominance (45 (73.8%)), and more than half of the suicides (32 (52.5%)) occurred among specialist doctors. Self poisoning, jumping from heights and firearms were the most common methods of suicide (18 (29.5%), 17 (27.9%) and 15 (24.6%), respectively). Cardiovascular surgery, family medicine, gynecology, and obstetrics specialties had the highest numbers of suicide deaths. Depression/mental illness was the most common speculated etiology. These results show that suicides among medical students and doctors in Turkey have characteristics that differ from both suicided among the general population in Turkey and doctor suicides in other countries.Conclusions. In this study, we identified the suicidal characteristics of medical students and doctors in Turkey for the first time. The results help us to better understand this understudied topic and provide an avenue for future studies. The data also indicate that it is important to monitor the individual and systemic difficulties experienced by doctors, starting from the medical education stage, and to provide individual and environmental support to help decrease the risk of suicide.

30MnB5 boron alloyed steel surface is coated using different coating techniques, namely 60(Ni-15Cr-4.4Si-3.5Fe-3.2B 0.7C)-40(WC 12Co) metallic powder plasma spray, Fe-28Cr-5C-1Mn alloy wire arc spray, WC-10Co-4Cr (thick) powder high velocity oxy-fuel (HVOF), and WC-10Co-4Cr (fine) diamond jet HVOF. The microstructure of the crude steel sample consists of ferrite and pearlite matrices and iron carbide structures. The intermediate binders are well bonded to the substrate for all coated surfaces. The arc spray coated surface shows the formation of lamellae. The cross-section of HVOF and diamond jet HVOF coated surfaces indicates the formation of WC, W2C Cr, and W parent matrix carbide structures. The corrosion characteristic of the coated steel has been investigated in 3.5 wt.% NaCl solution using electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDAX) techniques. The results reveal that the steel corroded in the medium despite the coatings. However, the extent of corrosion varies. HVOF coated sample demonstrated the highest corrosion resistance while arc spray coated sample exhibited the least. EDAX mapping reveals that the elements in the coatings corroded in the order of their standard electrode potential (SEP). Higher corrosion resistance of HVOF coated sample is linked to the low SEP of tungsten.

The investigation of structural, microstructural, optical, dielectric, and magnetic properties of double perovskite materials Zn2FeTiO6 (M1), Mg2FeTiO6 (M2), and Cu2FeTiO6 (M3) synthesized by solid-state reaction was reported in this work. The three compounds crystalized in a monoclinic structure with the space group of P121/c. The microstructure of M1, M2, M3 samples was scanned by SEM to show the crystallinity in shape, and elemental mappings from EDX confirmed the consistency with sample concentrations. Similar spectra were observed from the FTIR technique. The diffused reflectance in the 200–800 nm wavelength range and photoluminescence for the samples were measured to investigate the optical properties. Dielectric constants, conductivity, frequency dependence of the tangent loss (tan δ), AC conductivity at different dc bias voltages, and the electric modulus M(ω) were examined to ensure the potential of the examined materials for microelectronic applications in circuit devices.

Many additives are preferred to extend the usage of concrete constructions in order to increase durability. These compounds have to be non-poisonous and have no undesirable consequences on the environs. Out of all these concerns, amino acids are mainly used in food and drug industries as well as safe corrosion inhibitors in a number of acid solutions. Here, the corrosion inhibition efficacy of optimum concentration (50 ppm) of caffeine and L-arginine has been investigated for reinforcement steel in mixture water (MW) environment. This was performed for a duration of 2 h, 7, 28, 56 and 90 d using electrochemical impedance spectroscopy (EIS), dynamic EIS (DEIS), and potentiodynamic polarization (PDP) techniques. The surface of specimens was also investigated by atomic force microscopy (AFM), optical profilometer (OP) and scanning electron microscopy (SEM). DEIS results indicate that selected inhibitors protected reinforcement steel approximately up to 62% against corrosion till 7 d, then the effectiveness of the protection decreased to 30% on 90th day. It was also observed that L-arginine showed better inhibition efficiency than caffeine. Duzce University Research FundDuzce University [2019.06.05.1036] The authors acknowledge the financial support provided by the Duzce University Research Fund (Project No: 2019.06.05.1036). The authors also thank Dr. Marziya Rizvi (ORCID ID: 0000-0001-8928-529X) for his assistance in the interpretation of the EIS measurements. Africa Centre of Excellence in Future Energies and Electrochemical System, Federal University of Technology, Owerri, Nigeria is acknowledged for their contribution to this study. WOS:000650506200001 2-s2.0-85106258076

Plastik enjeksiyon üretiminde üretilen ürünün, kalıptan soğutularak çıkarılması için su kullanılmaktadır. Zamanla kullanıma bağlı olarak ısınan suyun sıcaklığını istenilen derecede tutmak için chiller cihazları kullanılmaktadır. Enjeksiyon makinelerinde ısınan su, chiller cihazlarında bulunan bakır serpantin (eşanjör) yardımıyla soğutularak tekrar kullanıma hazır hale getirilmektedir. Bu çalışmada; bakır serpantinin korozyonu yapay soğutma suyu (SCW) ve yapay soğutma suyuna katılan 1000 ppm NaNO2 ortamlarında 21 gün süreyle sürekli su devir daimi yapılarak araştırılmıştır. Deney öncesi ve sonrası bakır serpantinin yüzeyi Taramalı Elektron Mikroskobu (SEM), Enerji Dağılımlı X-Ray Kırınımı (EDS) ve Atomik Kuvvet Mikroskobu (AFM) yöntemleri ile incelenmiştir. Korozyon inhibitörü olarak kullanılan NaNO2 bileşiğinin, bakır serpantin üzerinde bir koruyucu film oluşturarak korozyona karşı koruduğu belirlenmiştir.Anahtar Kelimeler: Bakır serpantin, Korozyon, NaNO2, Yapay soğutma suyu, Water is used to remove the product generated in plastic injection production by cooling from the mold. Chiller devices are used to keep the temperature of the heated water at the desired temperature depending on the use over time. The water heated in the injection machines is cooled with the help of the copper serpentine (exchanger) in the chiller devices and made ready for use again. In this study; the corrosion of the copper serpentine was investigated in simulated cooling water (SCW) and 1000 ppm NaNO2 added simulated cooling water environments by continuous water circulation for 21 days. The surface of the copper serpentine was examined by Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Diffraction (EDS) and Atomic Force Microscope (AFM) before and after the experiments. It has been determined that the NaNO2 compound used as a corrosion inhibitor protects against corrosion by forming a protective layer on the copper serpentine.Keywords: Copper serpentine, Corrosion, NaNO2, Simulated cooling water

The corrosion inhibition behavior of sodium nitrite (NaNO2) towards pure copper (99.95%) in simulated cooling water (SCW) was investigated by means of electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS). NaNO2 interferes with metal dissolution and reduce the corrosion rate through the formation or maintenance of inhibitive film on the metal surface. Surface morphologies illustrated that the surface homogeneity increased on adding sodium nitrite. Sodium nitrite’s adsorption on copper surface followed the modified form of Langmuir, Freundlich and Frumkin isotherms. Physiosorption mode was involved in the corrosion protection. Electrochemical results revealed an corrosion resistance of copper increases on increasing the inhibitor concentration. The DEIS results indicated that copper corrosion mechanism could be hindered by 50% even after interval of 24 h by optimum concentration of sodium nitrite. The maximum inhibition was achieved with 2000 ppm of NaNO2. With this concentration, inhibition efficiency of up to 61.8% was achievable.

Nowadays, corrosion control of metals, whose area of use is increasing day by day, has technical, economic, and environmental importance. The most preferred of the various methods used to prevent corrosion is the addition of a suitable inhibitor to the environment. Corrosion inhibitors are widely used as they increase the service life of metals by forming a layer over the metallic substrate. Corrosion inhibitors are used in acidic, basic, and neutral environments. One of the most important factors affecting the corrosion behavior of metals in the environment is the pH value of the medium. It is known that metals which are generally corroded in acidic environments, are less corroded in alkaline environments. In this chapter, there are corrosion inhibitors used in alkaline environments. Accordingly, studies and research carried out on organic, inorganic, and green corrosion inhibitors used in basic environments have been organized in recent years.

Application of aluminium alloys is increasing in all industries due to its combined properties of low weight, good mechanical resistance, thermal conductivity, electrical conductivity, high strength, and good corrosion resistance. In particular, AA5083-H111 alloys have been successfully used in the maritime sector. Unlike purely surface treatments, cryogenic treatment is an inexpensive one-time process that influences the core properties of the components. Cryogenic treatment has recently been introduced to Al alloys. Although the main mechanisms are still ambiguous, considerable improvements on mechanical properties are well noted. However, the effect of cryogenic treatment on the corrosion of Al alloys is limited. This study investigated the effect of shallow cryogenic treatment (-80 °C) on the corrosion of 5083- H111 aluminium alloy, which is used particularly in the shipbuilding industry. Plates of 6-mm thickness exposed to a 3.5% NaCl environment were evaluated via Brinell hardness measurements, Electrochemical Impedance Spectroscopy (EIS) and surface monitoring methods including atomic force microscopy (AFM) and optical profilometry (OP) applied before and after the effect of cryogenic treatment. Results indicated that the duration time of cryogenic treatment (24 h, 36 h and 48 h) had little effect on changing the hardness values and corrosion response of AA5083-H111 alloy in the 3.5% NaCl environment.

Surfactants present exciting adsorption chemistry due to their dual nature, i.e the present of the hydrophobic and hydrophilic parts in their structures. However, the inhibition performance of surfactants is influenced by their chemical structure as well as the nature of the electrolyte. In acidic media, high concentration of tri-cationic surfactants is required for effective surface protection. Herein, we report the synthesis of a novel tri-cationic surfactant containing three quaternized nitrogen atoms and its corrosion inhibitive effect for carbon steel in 1 M aqueous HCl medium. The molecular structure of the surfactant was elucidated by 1H NMR and C-13 NMR spectroscopic techniques and its anti-corrosion activity was investigated by electrochemical impedance spectroscopy, potentiodynamic polarization and dynamic electrochemical impedance spectroscopy methods. The results obtained from the corrosion studies show that the synthesized surfactant is quite effective against the low carbon steel corrosion and at low inhibitor concentration. The inhibition efficiency obtained at 5 mg/L concentration is above 90%, showing that the anti-corrosion effect of the synthesized surfactant on the metal surface is strong even at low inhibitor concentration. Moreover, some physicochemical parameters namely, the critical micelle concentration, surface tension, micelle formation free energy, and emulsion stability have been calculated and used to explain the correlation with the corrosion inhibition mechanism. Additionally, to support the results from the electrochemical measurements, surface morphological examination using energy dispersive Xray spectroscopy (EDAX) and scanning electron microscope (SEM) methods have been performed. The EDAX and SEM results prove the adsorption of the tri-cationic surfactant molecule on the metal surface. The adsorption followed the Langmuir adsorption isotherm and calculated Kads (equilibrium constant of the adsorption process) value reflects strong interaction. More so, density functional theory (DFT) results corroborate the experimental results. The synthesized tri-cationic surfactant is a potential candidate for the formulation of acid corrosion inhibitor for acid cleaning applications. Research Foundation of Bursa Uludag University [OUAP(F)-2019/15] This work was supported by the Research Foundation of Bursa Uludag University under the Project Number: OUAP(F)-2019/15. WOS:000712117200006

The anticorrosion performance of ethanolic extract of propolis (EEP) on SAE 1010 carbon steel specimens dipped in 3.5% NaCl was evaluated by advanced electrochemical and surface morphological assessments. The adsorption of EEP on the surface of the specimens investigated was delineated by an optical profilometer (OP), atomic force microscopy (AFM), and scanning electron microscopy (SEM) before and after immersion in aqueous solution of 3.5% NaCl. The electrochemical feedback assisted by PDP, EIS, and DEIS of the inhibited electrodes was compared with that of the uninhibited electrodes, and EEP's role in the formation of a protective barrier was identified. All the qualitative and quantitative data thus obtained establish EEP as a potential inhibitor for the SAE 1010 carbon steel corrosion in NaCl solution. Duzce University Research FundDuzce University [2018.06.05.817, 19IN001804] For this work, the authors gratefully acknowledge the financial support provided by the Duzce University Research Fund [project no: 2018.06.05.817]. One of the authors thankfully acknowledges financial support provided by Turkiye Burslari (19IN001804) for this research. WOS:000535251500042 2-s2.0-85098670248

Gerengi, Husnu/0000-0002-9663-4264 WOS: 000514758800061 Considering the high neutralizing power of concrete, it is seen as the major material for preserving reinforcing steel. This is observed in reinforced concrete (RC) formation. It is obvious that under corrosive situations, concrete is subject to noticeable quality losses. The aim of this research is to conduct an inquiry on the disintegration of reinforcing steel subjected to 1 M HNO3 solution over 200 days. For this purpose, concrete samples were produced having three different formulations, which included the reference (pure Portland cement), 20% diatomite and 20% zeolite. Reinforcing steel was embedded into these concrete samples. Afterwards, the electrochemical impedance spectroscopy (EIS) approach was used to monitor the system every seven days. The results clearly revealed that long-term experiments are required for accurate electrochemical measurements. The addition of diatomite and zeolite protected the reinforcement better against corrosion. Although it loses its effectiveness over time, zeolite provided better resistance against corrosion than diatomite for the reinforcement bars in 1 M HNO3 solution. (C) 2019 Elsevier Ltd. All rights reserved. Duzce University Research FundDuzce University [2018.06.05.737] We acknowledge the financial help for this research provided by the Duzce University Research Fund (Project No: 2018.06.05.737). The authors also thank Dr. Agata Jazdzewska (Gdansk University of Technology- Poland) for her assistance during analysis of EIS results.

In this study, the effects of Cu and Fe additives on the structural, dielectric, magnetic, thermal and morphology of hydroxyapatite (HAp) samples were investigated and reported in detail for the first time. The prepared systems were also modeled and examined theoretically. It can be said that both additives affect the thermal behavior of the HAp structure. The addition of Cu affected the morphology of submicron-sized particles with spherical-like shapes with a low degree of agglomeration. Diffuse reflection data revealed that the energy band gap values decreased as Cu was added to the Fe-based HAp structure. The dielectric constant (epsilon') had high values at low frequencies in all samples and decreased with increasing frequency. It could be concluded that Fe/Cu incorporation to hydroxyapatites enhanced its thermal, magnetic, and dielectric properties required for mimicking natural HAps to open a successful venue for medical application in the healing regeneration of bone. Deanship for Scientific Research of Imam Abdulrahman Bin Faisal University [2020-170-IRMC] The authors acknowledge the financial supports provided by the Deanship for Scientific Research of Imam Abdulrahman Bin Faisal University (Project application No. 2020-170-IRMC) . Also, the authors acknowledge the facilities used at Institute for Research and Medical consultations (IRMC) at Imam Abdulrahman Bin Faisal University. WOS:000715133400001 2-s2.0-85118341098

YILDIZ, MESUT/0000-0001-6964-6705; KAYA, ERTUGRUL/0000-0003-1579-6411; Gerengi, Husnu/0000-0002-9663-4264; Solomon, Moses/0000-0002-3251-8846; Umoren, Saviour/0000-0002-8564-4897 WOS: 000425767400010 The efficacy of 1-butyl-1-methylpiperidinium tetrafluoroborate (BMPTFB) in retarding St37 steel corrosion in HCl environment has been examined using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), dynamic-EIS (DEIS), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) techniques. Results from all applied methods reveal that BMPTFB is effective in suppressing St37 dissolution in the studied corrosive medium. Inhibition efficiency of 88% has been achieved by 4mM BMPTFB. From DEIS results, BMPTFB is found to perform better as corrosion inhibitor at longer immersion time. The charge transfer resistance of the metal is raised in the presence of 4mM BMPTFB from 378 to 744 cm(2) at 1h and further increased to 867 cm(2) at 4h. BMPTFB, according to PDP result behaves as mixed-type corrosion inhibitor. Corrosion inhibition by BMPTFB is via adsorption which can best be explained using El-Awady kinetic/thermodynamic adsorption isotherm. K-ads and values indicate that physisorption is the mechanism of adsorption of BMPTFB molecules onto St37 surface. The presence of BMPTFB molecules on St37 surface has been verified by SEM and FTIR. Duzce University Research Council for Science and Technology (BAP) [2016.06.05.492] The authors acknowledge the following: (i) Dr Kazimierz Darowicki and Pawel Slepski for providing the DEIS software and (ii) Duzce University Research Council for Science and Technology (BAP) for the financial support (Project No. 2016.06.05.492).

The influence of cryogenic and cryogenic time (10, 24, 36, 48, and 72 h) on the hardness, surface roughness, and corrosion resistance properties of AA5083-H111 alloy in 3.5 wt.% NaCl solution have been investigated. The hardness property was analysed via the Brinell hardness measurement, the corrosion resistance property was measured electrochemically, while the morphological studies were undertaken using the SEM (scanning electron microscopy) and atomic force microscopy (AFM). The results disclose that the shallow cryogenic treatment at -80 degrees C improves the alloy's hardness, surface roughness, and the corrosion resistance. The best cryogenic treatment time is 24 h. Cryogenic treatment for 24 h increases the alloy's hardness from 71.3 HB to 74.90 HB, reduces the average surface roughness from 534.000 nm to 105.634 nm, and increases the total charge transfer resistance from 18139 omega cm(2) to 26230 omega cm(2). The improvement is linked to settling of fine particles on the alloy surface. The SEM results support these claims. Duzce University Research FundDuzce University [2020.06.05.1111] We acknowledge the financial assistance by the Duzce University Research Fund under the Project No: 2020.06.05.1111. The authors express their sincere gratitude to Prof. Dr Ilyas Uygur for aiding in the supply of AA5083-H111 alloys. WOS:000676024000001 2-s2.0-85111237752

Bu çalışmada referansnumunenin kimyasal kompozisyonuna sırasıyla ağırlıkça %0.05 ve %0.075 oranındaniyobyum ve vanadyum ilave edilmesiyle üretilen yeni alaşımların korozyonmekanizması %3.5 NaCl ortamında araştırılmıştır. Korozyon mekanizmasının anlıkbelirlenmesine olanak sağlayan Dinamik Elektrokimyasal Empedans Spektroskopisi (DEIS)yöntemi ilk defa bu çalışmayla mikroalaşım elementlerinin korozyona etkisininbelirlenmesinde kullanılmıştır. Hazırlanan numunelerin yüzey morfolojisi 15saat süren DEIS deneyleri sonunda optik mikroskopla incelenerek elektrokimyasalverilerle kıyaslanmıştır. Deney sonuçlarına göre niyobyum ve vanadyum miktarındakiartışın imal edilen yeni alaşımların %3.5 NaCl ortamında oluşan korozyonhızını azalttığını göstermektedir. Deney sonunda eldeedilen Rct değeri, alaşımelementlerinin ilavesiyle ortalama %44 ila %57 oranında artış göstermektedir.DEIS verileri ile optik resimler birbirini destekler niteliktedir. Alaşım elementleriilave edilmeyen numunenin yüzeyinde daha çok korozyon ve buna bağlı olarakdeformasyon olduğu görülmüştür.

Gerengi, Husnu/0000-0002-9663-4264; Solomon, Moses/0000-0002-3251-8846 WOS: 000395255900007 A study was conducted to assess the inhibitive effect of Diospyros kaki leaves extract on St37 steel corrosion in 0.1 M HCl solution. Electrochemical (PDP, EIS, DEIS), chemical, and surface morphological screening (SEM, EDS, FTIR) techniques were used in the study. Results show that D. kaki leaves extract is an excellent inhibitor for St37 steel in HCl solution. Maximum inhibition efficiency of 91% was afforded by the highest studied concentration of the extract from PDP measurements. PDP results reveal that the extract components act principally as cathodic type inhibitor suppressing the reduction of hydrogen ions in the cathodic region of the metal. DEIS results show that the studied systems exhibit non-stationary character and the adsorbed extract components were stable particularly at long exposure time. SEM, EDAX, and FTIR results support experimental results that components of D. kaki leaves extract were adsorbed on St37 surface. Duzce University Research FundDuzce University The authors gratefully acknowledge the financial support of this work by the Duzce University Research Fund. The authors also thank Murat Albayrak for his assistance during leaves collection.

The corrosion and corrosion inhibition of St37 steel in 0.1 M HCl solution by 1-ethyl-3-methylimidazolium tetrafluoroborate (EMITFB) and the effect of addition of KI on the inhibitive performance of EMITFB have been examined by electrochemical [electrochemical impedance spectroscopy, potentiodynamic polarization, and dynamic electrochemical impedance spectroscopy (DEIS)] and surface examination [scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS)] techniques. Results show that EMITFB could only afford the protection of St37 steel in HCl medium on an average scale. The highest studied concentration of EMITFB (4 mM) affords optimum inhibition efficiency of 78.86% from DEIS method. Addition of iodide ions to EMITFB has beneficial effect on the inhibition efficiency; 86.10% has been achieved by addition of 1 mM KI to 4 mM EMITFB. Adsorption of EMITFB molecules onto the metal surface is via physical adsorption mechanism and follows El Awady et al. kinetic/thermodynamic adsorption isotherm model. SEM and EDS results confirm the improvement of corrosion inhibiting ability of EMITFB by iodide ions. EMITFB and EMITFB + KI behave as mixed-type corrosion inhibitor in the studied environment. © 2018, Springer International Publishing AG, part of Springer Nature. Türkiye Bilimsel ve Teknolojik AraÅŸtirma Kurumu: TUBİTAK-114M933 Funding Husnu Gerengi thanks the Scientific and Technological Research Council of Turkey for the financial support under the TUBİTAK-114M933 coded project. Moses M. Solomon is grateful to King Fahd University of Petroleum and Minerals, Saudi Arabia for accepting him as a Postdoctoral Research Fellow.

YILDIZ, MESUT/0000-0001-6964-6705; Gerengi, Husnu/0000-0002-9663-4264; Solomon, Moses/0000-0002-3251-8846; KAYA, ERTUGRUL/0000-0003-1579-6411 WOS: 000428110500008 The corrosion inhibition of AA2024-T4 in 3.5% NaCl solution by 8-hydroxylquinoline (8-HQ) was investigated by potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy and dynamic electrochemical impedance spectroscopy. Experimental results were supported with scanning electron microscopy (SEM), atomic force microscopy and Fourier transform-infrared (FTIR) spectroscopy analysis. It was found that 8-HQ molecules adsorbed on the alloy surface and protected it against corrosion. SEM, energy dispersive spectroscopy, and FTIR results confirm the adsorption of 8-HQ molecules on AA2024-T4. The inhibition efficiency of 8-HQ is found to increase with increase in concentration and the highest concentration studied (0.05 M) offered corrosion inhibition efficiency of 84%. PDP results show that 8-HQ acts as mixed type inhibitor in the studied medium. Duzce UniversityDuzce University [BAP-2015.26.04.365] This work was supported by Duzce University Research Fund [project number BAP-2015.26.04.365].