期刊文献+
共找到37篇文章
< 1 2 >
每页显示 20 50 100
Novel tumor marker index combining carcinoembryonic antigen and carbohydrate antigen 19-9:New prognostic factor for metastatic colorectal cancer
1
作者 Yusuf Ilhan Onur Yazdan Balcik +11 位作者 Halil Goksel Guzel Arif Hakan Onder Bilgin Demir Mehmet Nuri Baser Ibrahim Karadag Mehmet Fatih Ozbay Tugrul Burak Genc Sahnura Uzuntas Oguz Poyrazoglu Ismail Beypinar Yakup Ergun Banu Ozturk 《World Journal of Gastrointestinal Oncology》 2025年第5期192-206,共15页
BACKGROUND Metastatic colorectal cancer(mCRC)is a global health challenge with a poor prognosis.Prognostic markers are critical for survival prediction.METHODS This multicenter,retrospective study measured baseline ca... BACKGROUND Metastatic colorectal cancer(mCRC)is a global health challenge with a poor prognosis.Prognostic markers are critical for survival prediction.METHODS This multicenter,retrospective study measured baseline carcinoembryonic antigen and carbohydrate antigen 19-9 levels to calculate a TMI as the geometric mean of values normalized to their upper limits of normal.Receiver operating characteristic curve analysis assessed TMI’s prognostic accuracy,and patients were stratified into high-TMI(≥1.39)and low-TMI(<1.39)groups.The primary endpoint was overall survival(OS),with progression-free survival and treatment response as secondary endpoints.RESULTS The study included 305 mCRC patients with a median follow-up of 22.9 months.The median OS for high-TMI patients was 29.5 months,significantly lower than the 45.6 months observed in the low-TMI group(P=0.02).The 2-year OS rates for the high-and low-TMI groups were 59.4%and 72.9%,respectively.Median progression-free survival was also shorter for the high-TMI group(14.0 vs 16.0 months,P=0.84).High TMI is an independent prognostic factor for worse OS.CONCLUSION TMI is a simple,cost-effective prognostic tool for mCRC,with high TMI associated with poorer survival outcomes. 展开更多
关键词 Colorectal cancer biomarkers Metastatic colorectal cancer Carcinoembryonic antigen Carbohydrate antigen 19-9 Tumor marker index
暂未订购
Determination of the Relationship between Empathy and Compassion Fatigue in Pediatric Clinic Nurses
2
作者 Dilek Akıncı HacerÇetin Serpil Yılmaz 《International Journal of Mental Health Promotion》 2024年第11期935-942,共8页
Background:This study aimed to determine the relationship between compassion fatigue and empathic disposition and skill levels of pediatric clinic nurses.Methods:This research was carried out as a descriptive and cros... Background:This study aimed to determine the relationship between compassion fatigue and empathic disposition and skill levels of pediatric clinic nurses.Methods:This research was carried out as a descriptive and cross-sectional study.The research was carried out with 233 nurses determined by using a stratified sampling method from 648 nurses working in two University Hospital and two City Hospital children’s clinics.Data were collected using the“Personal Information Form”,“Compassion Scale(CS)”,“Empathic Tendency Scale(ETS)”and“Empathic Skill Scale(ESS)”.Pearson Correlation test,Student’s t-test,ANOVA test,and Scheffe test were used in the analysis of the data.Results:The mean age of the nurses participating in the study was 30.93±6.23 years,81.1%were women and 54.9%were married.Pediatric clinic nurses’mean compassion score was 96.29±11.64,empathic tendency mean score was 69.30±8.39,and empathic skill mean score was 140.82±23.15.According to the findings obtained,the mean compassion score of the male,married,and nurses who were not satisfied with working in the pediatric clinics and working in the pediatric emergency clinics was found to be the lowest(p<0.05,p<0.01,p<0.001).The empathic disposition mean scores of the nurses working in the pediatric inpatient clinics,who were satisfied with working in the pediatric clinic,and who did not have the thought of moving to another clinic,were found to be significantly higher(p<0.01,p<0.001).The mean scores of empathic skills of nurses working only during the daytime were found to be significantly higher(p<0.001).Conclusion:This study confirms that pediatric clinic nurses are experiencing compassion fatigue at the end of COVID-19 and how this situation negatively affects their empathic tendencies and skills.The study highlights the need for both clinical and management-based planning to prevent compassion fatigue and increase empathic tendencies and skills in Pediatric clinic nurses. 展开更多
关键词 Pediatric clinic compassion fatigue EMPATHY NURSING CARE
暂未订购
Is the neutrophil to lymphocyte ratio associated with liver fibrosis in patients with chronic hepatitis B? 被引量:15
3
作者 Murat Kekilli Alpaslan Tanoglu +3 位作者 Yusuf Serdar Sakin Mevlut Kurt Serkan Ocal Sait Bagci 《World Journal of Gastroenterology》 SCIE CAS 2015年第18期5575-5581,共7页
AIM: To determine the association between the neutrophil to lymphocyte(N/L) ratio and the degree of liver fibrosis in patients with chronic hepatitis B(CHB) infection. METHODS: Between December 2011 and February 2013,... AIM: To determine the association between the neutrophil to lymphocyte(N/L) ratio and the degree of liver fibrosis in patients with chronic hepatitis B(CHB) infection. METHODS: Between December 2011 and February 2013, 129 consecutive CHB patients who were admitted to the study hospitals for histological evaluation of chronic hepatitis B-related liver fibrosis were included in this retrospective study. The patients were divided into two groups based on the fibrosis score: individuals with a fibrosis score of F0 or F1 were included in the "no/minimal liver fibrosis" group, whereas patients with a fibrosis score of F2, F3, or F4 were included in the "advanced liver fibrosis" group. The Statistical Package for Social Sciences 18.0 for Windows was used to analyze the data. A P value of < 0.05 was accepted as statistically significant.RESULTS: Three experienced and blinded pathologists evaluated the fibrotic status and inflammatory activity of 129 liver biopsy samples from the CHB patients. Following histopathological examination, the "no/minimal fibrosis" group included 79 individuals, while the "advanced fibrosis" group included 50 individuals. Mean(N/L) ratio levels were notably lower in patients with advanced fibrosis when compared with patients with no/minimal fibrosis. The mean value of the aspartate aminotransferase-platelet ratio index was markedly higher in cases with advanced fibrosis compared to those with no/minimal fibrosis.CONCLUSION: Reduced levels of the peripheral blood N/L ratio were found to give high sensitivity, specificity and predictive values in CHB patients with significant fibrosis. The prominent finding of our research suggests that the N/L ratio can be used as a novel noninvasive marker of fibrosis in patients with CHB. 展开更多
关键词 Chronic HEPATITIS B Liver FIBROSIS NEUTROPHIL to LYMPHOCYTE ratio Fibrotic stage Inflammatory activity NON-INVASIVE marker
暂未订购
A bibliometric analysis of academic publication on diabetic retinopathy disease trends during 1980-2014:a global and medical view 被引量:7
4
作者 Cagatay Caglar Emre Demir +1 位作者 Ferit Kerim Kucukler Mustafa Durmus 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2016年第11期1663-1668,共6页
AIM: To investigate diabetic retinopathy(DR) literature using the Institute for Scientific Information(ISI) Web of Science(Wo S) database and to analyse the correlation results between socio-economic developmen... AIM: To investigate diabetic retinopathy(DR) literature using the Institute for Scientific Information(ISI) Web of Science(Wo S) database and to analyse the correlation results between socio-economic development datas and number of DR publications.METHODS: The statistical analysis of the documents published during 1980-2014 was analysed. The data of this study were based on the database of Wo S. "Diabetic retinopathy" was used as the keywords to search the Wo S database.RESULTS: The United States ranked first in the DR research with 1840 publications and 24.38% of the world production followed by England and Japan. Besides, the most productive country was Iceland. A high correlation was found between number of publications and 2014 gross domestic product( GDP) values of 81 countries(r =0.800, P 〈0.001). We found a significant correlation between number of publications and Human Development Index(HDI)(r =0.645, P =0.001). There is a moderate correlation between people with diabetes and number of DR publications for 81 countries(r =0.514, P 〈0.01). It could be analysed that estimated publication number with DR title will be 445 according to the regression curve constituted with cubic model in 2015(R2=1.000).CONCLUSION: More DR studies have been published in developed countries, DR and other complications of diabetes have gradually increased in developing countries over recent decades. It can be expected that the number of DR studies will gradually increase in developing countries. 展开更多
关键词 BIBLIOMETRICS correlation analysis developingcountries diabetic retinopathy socio-economic development
原文传递
One-step electrochemical reduction of stibnite concentrate in molten borax 被引量:6
5
作者 Levent Kartal Mehmet Baris Daryal +1 位作者 Güldem Kartal Sireli Servet Timur 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2019年第10期1258-1265,共8页
In this study,antimony production from a stibnite concentrate(Sb2S3)was performed in one step using a molten salt electrolysis method and borax as an electrolyte.Electrochemical reduction of the stibnite concentrate w... In this study,antimony production from a stibnite concentrate(Sb2S3)was performed in one step using a molten salt electrolysis method and borax as an electrolyte.Electrochemical reduction of the stibnite concentrate was performed at 800℃under galvanostatic conditions and explained in detail by the reactions and intermediate compounds formed in the borax.The effects of current density(100 800 mA cm^-2)and electrolysis time(10 40 min)on cathodic current efficiency and antimony yields were systematically investigated.During the highest current efficiency,which was obtained at 600 mA cm^-2,direct metal production was possible with 62%cathodic current efficiency and approximately 6 kWh/kg energy consumption.At the end of the 40-min electrolysis duration at 600 mA cm^-2 current density,antimony reduction reached 30.7 g and 99%of the antimony fed to the cell was obtained as metal. 展开更多
关键词 MOLTEN salt ELECTROLYSIS electrochemical reduction ANTIMONY ANTIMONY extraction STIBNITE BORAX
在线阅读 下载PDF
Direct electrochemical reduction of copper sulfide in molten borax 被引量:4
6
作者 Levent Kartal Servet Timur 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2019年第8期992-998,共7页
In this study,for the first time,direct copper production from copper sulfide was carried out via direct electrochemical reduction method using inexpensive and stable molten borax electrolyte.The effects of current de... In this study,for the first time,direct copper production from copper sulfide was carried out via direct electrochemical reduction method using inexpensive and stable molten borax electrolyte.The effects of current density(100–800 mA/cm^2)and electrolysis time(15–90 min)on both the cathodic current efficiency and copper yield were systematically investigated in consideration of possible electrochemical/chemical reactions at 1200℃.The copper production yield reached 98.09%after 90 min of electrolysis at a current density of 600 mA/cm^2.Direct metal production was shown to be possible with 6 kWh/kg energy consumption at a 600 mA/cm2 current density,at which the highest current efficiency(41%)was obtained.The suggested method can also be applied to metal/alloy production from single-and mixed-metal sulfides coming from primary production and precipitated sulfides,which are produced in the mining and metallurgical industries during treatment of process solutions or wastewaters. 展开更多
关键词 MOLTEN salt ELECTROLYSIS ELECTRO-REDUCTION COPPER extraction COPPER SULFIDE BORAX
在线阅读 下载PDF
Low temperature thermoluminescence behaviour of Y_2O_3 nanoparticles 被引量:4
7
作者 S.Delice M.Isik N.M.Gasanly 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第1期19-23,M0002,共6页
Y_2O_3 nanoparticles were investigated using low temperature thermoluminescence (TL) experiments. TL glow curve recorded at constant heating rate of 0.4 K/s exhibits seven peaks around 19, 62, 91,115,162,196 and 215 K... Y_2O_3 nanoparticles were investigated using low temperature thermoluminescence (TL) experiments. TL glow curve recorded at constant heating rate of 0.4 K/s exhibits seven peaks around 19, 62, 91,115,162,196 and 215 K. Activation energies and characteristics of traps responsible for observed curves were revealed under the light of results of initial rise analyses and T_(max)-T_(stop) experimental methods. Analyses of TL curves obtained at different stopping temperatures resulted in presence of one quasi-continuously distributed trap with activation energies increasing from 18 to 24 meV and six single trapping centers at49, 117, 315, 409, 651 and 740 meV. Activation energies of all revealed centers were reported in the present paper. Structural characterization of Y_2O_3 nanoparticles was accomplished using X-ray diffraction and scanning electron microscopy measurements. 展开更多
关键词 Y2O3 LUMINESCENCE THERMOLUMINESCENCE DEFECTS RARE earths
原文传递
Reciprocating sliding wear properties of sintered Al-B_(4)C composites 被引量:3
8
作者 Mahmut Can Şenel Yusuf Kanca Mevlüt Gürbüz 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2022年第6期1261-1269,共9页
The fabrication of boron carbide reinforced aluminum matrix composites(Al-B_(4)C)with various contents of B_(4)C(1wt%,6wt%,15wt%,and 30wt%)was performed by powder metallurgy,and the influence of the content of B_(4)C ... The fabrication of boron carbide reinforced aluminum matrix composites(Al-B_(4)C)with various contents of B_(4)C(1wt%,6wt%,15wt%,and 30wt%)was performed by powder metallurgy,and the influence of the content of B_(4)C on their mechanical and tribological behavior was examined.The Al-30B_(4)C composites recorded the highest density(~2.54 g/cm^(3)),lowest porosity(4%),maximum Vickers hardness(HV~75),lowest weight loss(0.4 mg),and lowest specific wear rate(0.00042 mm^(3)/(N·m))under a load of 7 N,with an enhancement of 167%in hardness,a decrease of 75.8%in weight loss,and a decrease of 76.7%in the specific wear rate compared with pure aluminum.In addition,the scanning electron microscope images of the worn surface revealed that the Al-B_(4)C composite has the narrowest wear groove of 0.85 mm at a load of 7 N,and the main wear mechanism was observed as an abrasive wear mechanism.According to the friction analysis,the coefficient of friction between surfaces increased with increasing boron carbide content and with decreasing applied load.In conclusion,B_(4)C is an effective reinforcement material in terms of tribological and mechanical performance of the Al-B_(4)C composites. 展开更多
关键词 ALUMINUM boron carbide COMPOSITE WEAR FRICTION
在线阅读 下载PDF
Gastric neuroendocrine neoplasms: A review 被引量:3
9
作者 Huseyin Koseoglu Tolga Duzenli Mesut Sezikli 《World Journal of Clinical Cases》 SCIE 2021年第27期7973-7985,共13页
Gastric neuroendocrine neoplasms(g-NENs)or neuroendocrine tumors are generally slow-growing tumors with increasing incidence.They arise from enterochromaffin like cells and are divided into four types according to cli... Gastric neuroendocrine neoplasms(g-NENs)or neuroendocrine tumors are generally slow-growing tumors with increasing incidence.They arise from enterochromaffin like cells and are divided into four types according to clinical characteristic features.Type 1 and 2 are gastrin dependent,whereas type 3 and 4 are sporadic.The reason for hypergastrinemia is atrophic gastritis in type 1,and gastrin releasing tumor(gastrinoma)in type 2 g-NEN.The diagnosis of g-NENs needs histopathological investigation taken by upper gastrointestinal endoscopy.g-NENs are positively stained with chomogranin A and synaptophysin.Grading is made with mitotic index and ki-67 proliferation index on histopathological analysis.It is crucial to discriminate between types of g-NENs,because the management,treatment and prognosis differ significantly between subtypes.Treatment options for g-NENs include endoscopic resection,surgical resection with or without antrectomy,medical treatment with somatostatin analogues,netazepide or chemotherapy regimens.Follow-up without excision is another option in appropriate cases.The prognosis of type 1 and 2 g-NENs are good,whereas the prognosis of type 3 and 4 g-NENs are close to the prognosis of gastric adenocancer. 展开更多
关键词 Gastric neuroendocrine tumors Gastric neuroendocrine neoplasm Gastric neuroendocrine carcinoma HYPERGASTRINEMIA CARCINOID Somatostatin receptor imaging
暂未订购
Electrolytic production of Cu-Ni alloys in CaCl_2-Cu_2S-NiS molten salt 被引量:2
10
作者 Levent KARTAL Servet TIMUR 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第10期2143-2150,共8页
An alternative metal/alloy production method,known as direct electrochemical reduction(DER),was introduced for the fabrication of CuNi alloys from mixed sulfides(Cu2S,NiS)under both galvanostatic and potentiostatic co... An alternative metal/alloy production method,known as direct electrochemical reduction(DER),was introduced for the fabrication of CuNi alloys from mixed sulfides(Cu2S,NiS)under both galvanostatic and potentiostatic conditions.The influences of the process parameters(e.g.,cell voltage and current)on the compositions of the reduced compounds were investigated to yield industrially desirable alloys,namely,CuNi10,CuNi20,and CuNi30.The electrochemical behaviors of Cu2S and NiS in CaCl2 melt were examined at a temperature of 1200°C via cyclic voltammetry(CV).Based on the CV results,the cathodic reduction of Cu2S occurred in one step and cathodic reductions of NiS occurred in two steps,i.e.,Cu2S?Cu for copper reduction and NiS?Ni3S2?Ni for nickel reduction.Galvanostatic studies revealed that it was possible to fabricate high-purity CuNi10 alloys containing a maximum sulfur content of 320×10-6 via electrolysis at 10 A for 15 min.Scanning electron microscopy along with energy-dispersive X-ray spectrometry and optical emission spectroscopy(OES)examinations showed that it was possible to fabricate CuNi alloys of preferred compositions and with low levels of impurities,i.e.,less than 60×10-6 sulfur,via DER at 2.5 V for 15 min. 展开更多
关键词 molten salt electrolysis ELECTRO-REDUCTION copper extraction copper sulfide nickel sulfide Cu-Ni alloys
在线阅读 下载PDF
Role of matrix structure and flaw size distribution modification on deflection hardening behavior of polyvinyl alcohol fiber reinforced engineered cementitious composites(PVA-ECC) 被引量:2
11
作者 Kamile TOSUN FELEKOĞLU Eren GÖDEK 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第12期3279-3294,共16页
The multiple cracking and deflection hardening performance of polyvinyl alcohol fiber reinforced engineered cementitious composites(PVA-ECC)under four-point flexural loading have been investigated.Matrices with differ... The multiple cracking and deflection hardening performance of polyvinyl alcohol fiber reinforced engineered cementitious composites(PVA-ECC)under four-point flexural loading have been investigated.Matrices with different binder combinations and W/B ratios(from 0.44 to 0.78)providing satisfactory PVA fiber dispersion were specially designed.Effect of pre-existing flaw size distribution modification on deflection hardening behavior was comparatively studied by adding 3 mm diameter polyethylene beads into the mixtures(6%by total volume).Natural flaw size distributions of composites without beads were determined by cross sectional analysis.The crack number and crack width distributions of specimens after flexural loading were characterized and the possible causes of changes in multiple cracking and deflection hardening behavior by flaw size distribution modification were discussed.Promising results from the view point of deflection hardening behavior were obtained from metakaolin incorporated and flaw size distribution modified PVA-ECCs prepared with W/B=0.53.The dual roles of W/B ratio and superplasticizer content on flaw size distribution,cracking potential and fiber-matrix bond behavior were evaluated.Flaw size distribution modification is found beneficial in terms of ductility improvement at an optimized W/B ratio. 展开更多
关键词 fiber reinforced cementitious composites METAKAOLIN deflection hardening multiple cracking flaw size distribution
在线阅读 下载PDF
Impact of different sampling rates on precise point positioning performance using online processing service 被引量:2
12
作者 Serdar Erol Reha Metin Alkan +1 位作者 İ.Murat Ozulu Veli Ilçi 《Geo-Spatial Information Science》 SCIE CSCD 2021年第2期302-312,I0008,共12页
In this study,the effect of different sampling rates(i.e.observation recording interval)on the Precise Point Positioning(PPP)solutions in terms of accuracy was investigated.For this purpose,a field test was carried ou... In this study,the effect of different sampling rates(i.e.observation recording interval)on the Precise Point Positioning(PPP)solutions in terms of accuracy was investigated.For this purpose,a field test was carried out inÇorum province,Turkey,on 11 September 2019.Within this context,a Geodetic Point(GP)was established and precisely coordinated.A static GNSS measurement was occupied on the GP for about 4-hour time at 0.10 second(s)/10 Hz measurement intervals with the Trimble R10 geodetic grade GNSS receiver.The original observation file was converted to RINEX format and then decimated into the different data sampling rates as 0.2 s,0.5 s,1 s,5 s,10 s,30 s,60 s,and 120 s.All these RINEX observation files were submitted to the Canadian Spatial Reference System-Precise Point Positioning(CSRS-PPP)online processing service the day after the data collection date by choosing both static and kinematic processing options.In this way,PPP-derived static coordinates,and the kinematic coordinates of each measurement epoch were calculated.The PPP-derived coordinates obtained from each decimated sampling intervals were compared to known coordinates of the GP for northing,easting,2D position,and height components.According to the static and kinematic processing results,high data sampling rates did not change the PPP solutions in terms of accuracy when compared to the results obtained using lower sampling rates.The results of this study imply that it was not necessary to collect GNSS data with high-rate intervals for many surveying projects requiring cm-level accuracy. 展开更多
关键词 Precise Point Positioning(PPP) online GNSS postprocessing service high-rate GNSS sampling rate monitoring structure behavior
原文传递
Colorectal stenting for palliation and as a bridge to surgery:A 5-year follow-up study 被引量:3
13
作者 Baris Bayraktar Ibrahim Ali Ozemir +6 位作者 Umut Kefeli Gokhan Demiral Julide Sagiro?lu Onur Bayraktar Gupse Adali Alp Ozcelik Osman Baran Tortum 《World Journal of Gastroenterology》 SCIE CAS 2015年第31期9373-9379,共7页
AIM: To evaluate the long-term effectiveness of colonic stents in colorectal tumors causing large bowel obstruction.METHODS: We retrospectively analyzed data from 49 patients with colorectal cancer who had undergone c... AIM: To evaluate the long-term effectiveness of colonic stents in colorectal tumors causing large bowel obstruction.METHODS: We retrospectively analyzed data from 49 patients with colorectal cancer who had undergone colorectal stent placement between January 2008 and January 2013. Patients' symptoms,characteristics and clinicopathological data were obtained by reviewing medical records. The obstruction was diagnosed clinically and radiologically. Histopathological diagnosis was achieved endoscopically. Technical success rate(TSR)was defined as the ratio of patients with correctly placed SEMS upon stent deployment across the entire stricture length to total number of patients. Clinical success rate(CSR) was defined as the ratio of patients with technical success and successful maintenance of stent function before elective surgery(regardless of number of SEMS deployed) to total number of patients. The surgical success rate(SSR) of colorectal stent as a bridge to surgery was defined as the ratio of patients with successful surgical procedures. Unsuccessful surgical outcomes were defined as being due to insufficient colonic decompression. The technical,clinical,surgical success rates and complications after stenting were assessed.RESULTS: The median age of patients was 64(36 to 89). 44.9% of patients were male and 55.1% were female. Eighteen patients had the obstruction located in the rectum,15 patients in the rectosigmoid region,10 patients in the sigmoid region,and 6 patients had a tumor causing obstruction in the proximal colon. Each patient was categorized pathologically as stage 2(32.7%,16 patients) or stage 3(42.9%,21 patients) and 12 patients(24.4%) had metastatic disease. None of the patients received chemotherapy before stenting. Stenting was undertaken in 37 patients as a bridge to surgery,and in 12 patients stents were used for palliation. Median time to surgery after stenting was 30 ± 91.9 d. All surgery was completed in one single operation and thus no colostomy with stoma was needed. The median overall survival rate of patients with stage 2-3 colorectal cancer was 53.1 mo and stage 4 was 37.1 mo(P = 0.04). Metastatic colorectal patients who were treated palliatively with stents had backbone chemotherapy with oxaliplatin and/or irinotecan-based regimens plus antiangiogenic therapies,especially bevacizumab. Resolution of the obstruction and clinical improvement was achieved in all patients. The technical,clinical and surgical success rates were 95.9%,100% and 94.6%,respectively.CONCLUSION: The efficacy and safety of colonic stents was demonstrated both as a bridge to surgery and for palliative decompression. In addition,results emphasize the importance of the skills of the endoscopist in colonic stenting. 展开更多
关键词 Large bowel obstruction Colonic decom-pression Colorectal tumors Metallic stent Palliative therapy
暂未订购
Embedded Atom Method-Based Geometry Optimization Aspects of Body-Centered Cubic Metals 被引量:1
14
作者 M.Güler E.Güler 《Chinese Physics Letters》 SCIE CAS CSCD 2013年第5期112-115,共4页
We present embedded atom method-based geometry optimization calculations for Fe, Cr, Mo, Nb, Ta, V and W body-centered cubic metals with Finnis–Sinclair potentials. After the optimization, we determine their typical ... We present embedded atom method-based geometry optimization calculations for Fe, Cr, Mo, Nb, Ta, V and W body-centered cubic metals with Finnis–Sinclair potentials. After the optimization, we determine their typical elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's ratios, elastic wave velocities and cohesive energies. Additionally, we perform a benchmark between the experiments and the available density functional theory results. In general, our results show a good consistency with previous findings on the elastic and cohesive energy properties of the considered metals. 展开更多
关键词 MODULUS OPTIMIZATION CUBIC
原文传递
Co-substitution of zirconium and neodymium on hyperfine interactions and AC susceptibility of SrFe12O19 nanohexaferrites 被引量:2
15
作者 M.A.Almessere Y.Slimani +1 位作者 H.Güngünes A.Baykal 《Journal of Rare Earths》 SCIE EI CAS CSCD 2020年第3期265-273,共9页
This study presents the influence of Zn and Nd co-substitution on structure,morphology,AC susceptibility and ZFC-FC magnetizations of Sr nanohexaferrites(NHFs),SrFe12-x(Zn,Nd)xO19(0.0≤x≤1.0),which was produced by so... This study presents the influence of Zn and Nd co-substitution on structure,morphology,AC susceptibility and ZFC-FC magnetizations of Sr nanohexaferrites(NHFs),SrFe12-x(Zn,Nd)xO19(0.0≤x≤1.0),which was produced by sol-gel approach.XRD powder patterns,scanning electron microscopy(SEM) and high-resolution transmission electron spectroscopy(HR-TEM) approve the synthesis of Sr M-type hexaferrite.Mossbauer spectra show that Zn^2+ions occupy 2 b and 4f1 sites while Nd3+ions locate at 2 a,4f2 and 12 k sites.The magnetic properties of the produced Sr-NHFs were investigated also by ZFC-FC magnetizations and AC susceptibility.According to the MFC-MZFC results(between 2 and 400 K),no blocking temperature was detected which indicates the ferromagnetic(FM) behavior of NHFs.At lower temperatures,a super-spin glass like behavior is discerned.The AC susceptibility indicates that the magnetic interactions are improved due to the inclusion of low content(x=0.1) of Nd^3+and Zn^2+ions into the Sr-NHFs.However,with further increasing the Nd^3+and Zn^2+contents(x=0.9),the magnetic interactions are weakened. 展开更多
关键词 Sr HEXAFERRITES Rare earths MOSSBAUER spectroscopy AC susceptibility ZFC-FC
原文传递
Synthesis, characterization and radioluminescence properties of erbium-doped yttria phosphors 被引量:1
16
作者 Fatma Unal Faruk Kaya Kursat Kazmanli 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2021年第12期1983-1990,共8页
Radioluminescence(RL)behaviour of erbium-doped yttria nanoparticles(Y2O_(3):Er^(3+)NPs)which were produced by sol-gel method was reported for future scintillator applications.NPs with dopant rates of 1 at%,5 at%,10 at... Radioluminescence(RL)behaviour of erbium-doped yttria nanoparticles(Y2O_(3):Er^(3+)NPs)which were produced by sol-gel method was reported for future scintillator applications.NPs with dopant rates of 1 at%,5 at%,10 at%and 20 at%Er were produced and calcined at 800℃,and effect of increased calcination temperature(1100℃)on the RL behaviour was also reported.X-ray diffraction(XRD)results showed that all phosphors had the cubic Y2O_(3) bixbyite-type structure.The lattice parameters,crystallite sizes(CS),and lattice strain values were calculated by Cohen-Wagner(C-W)and Williamson-Hall(W-H)methods,respectively.Additionally,the optimum solubility value of the Er^(3+)dopant ion in the Y2O_(3) host lattice was calculated to be approximately 4 at%according to Vegard’s law,which was experimentally obtained from the 5 at%Er^(3+)ion containing solution.Both peak shifts in XRD patterns and X-ray photoelectron spectroscopy(XPS)analyses confirmed that Er^(3+)dopant ions were successfully incorporated into the Y2O_(3) host structure.High-resolution transmission electron microscopy(HRTEM)results verified the average CS values and agglomerated NPs morphologies were revealed.Scanning electron microscopy(SEM)results showed the neck formation between the particles due to increased calcination temperature.As a result of the RL measurements under a Cu KαX-ray radiation(wavelength,λ=0.154 nm)source with 50 kV and 10 mA beam current,it was determined that the highest RL emission belonged to 5 at%Er doped sample.In the RL emission spectrum,the emission peaks were observed in the wavelength ranges of 510-575 nm(2H11/2,4S3/2-4I15/2;green emission)and 645-690 nm(4F9/2-4I15/2;red emission).The emission peaks at 581,583,587,593,601,611 and 632 nm wavelengths were also detected.It was found that both dopant rate and calcination temperature affected the RL emission intensity.The color shifted from red to green with increasing calcination temperature which was attributed to the increased crystallinity and reduced crystal defects. 展开更多
关键词 structure. temperature. solution.
在线阅读 下载PDF
Performance analysis of real-time and post-mission kinematic precise point positioning in marine environments 被引量:1
17
作者 Serdar Erol Reha Metin Alkan +1 位作者 I.Murat Ozulu Veli Ilçi 《Geodesy and Geodynamics》 2020年第6期401-410,共10页
This article focuses on the performance analysis of both real-time and post-mission kinematic precise point positioning(PPP)in challenging marine environments.For this purpose,a real dynamic experiment lasting 6 h was... This article focuses on the performance analysis of both real-time and post-mission kinematic precise point positioning(PPP)in challenging marine environments.For this purpose,a real dynamic experiment lasting 6 h was carried out on a lake dam in?orum City of Turkey.While the kinematic test was continuing,the real-time PPP coordinates were obtained for each measurement epoch with a commercial real-time PPP(RT-PPP)service,namely the Trimble Center Point RTX.Then the post-mission PPP(PM-PPP)coordinates were calculated by using Multi-GNSS data and the Multi-GNSS Experiment(MGEX)precise products.The kinematic RT-PPP and PM-PPP results showed that the PPP coordinates were consistent with the relative solution at centimetre and decimetre level in horizontal and height components,respectively.This study implies that PPP technique is a powerful tool for highly accurate positioning in both real-time and post-mission modes,even for dynamic applications in harsh environments. 展开更多
关键词 Kinematic survey Precise point positioning Real-time PPP IGS-RTS Global GNSS correction service
原文传递
Pentamidine in Pneumocystis jirovecii prophylaxis in heart transplant recipients 被引量:1
18
作者 Adem Ilkay Diken Ozlem Er?en Diken +4 位作者 Onur Hanedan Seyhan Y?lmaz Ata Niyazi Ecevit Emir Erol Adnan Yal??nkaya 《World Journal of Transplantation》 2016年第1期193-198,共6页
Despite advances in transplantation techniques and the quality of post-transplantation care, opportunistic infections remain an important cause of complications. Pneumocystis jirovecii(P. jirovecii) is an opportunisti... Despite advances in transplantation techniques and the quality of post-transplantation care, opportunistic infections remain an important cause of complications. Pneumocystis jirovecii(P. jirovecii) is an opportunistic organism, represents an important cause of infections in heart transplantation patients. Almost 2% to 10% of patients undergoing cardiac transplantation have Pneumocystis pneumonia. Prophylaxis is essential after surgery. Various prophylaxis regimes had been defined in past and have different advantages. Trimethoprim/sulfamethoxazole(TMP/SMX) has a key role in prophylaxis against P. jirovecii. Generally, although TMP/SMX is well tolerated, serious side effects have also been reported during its use. Pentamidine is an alternative prophylaxis agent when TMP/SMX cannot be tolerated by the patient. Structurally, pentamidine is an aromatic diamidine compound with antiprotozoal activity. Since it is not effectively absorbed from the gastrointestinal tract, it is frequently administered via the intravenous route. Pentamidine can alternatively be administered through inhalation at a monthly dose in heart transplant recipients. Although, the efficiency and safety of this drug is well studied in other types of solid organ transplantations, there are only few data about pentamidine usage in heart transplantation. We sought to evaluate evidence-based assessment of the use of pentamidine against P. jirovecii after heart transplantation. 展开更多
关键词 PENTAMIDINE PROPHYLAXIS TRIMETHOPRIM Heart transplantation PNEUMOCYSTIS PNEUMONIA PNEUMOCYSTIS jirovecii PNEUMOCYSTIS carinii
暂未订购
Peripapillary and macular vascular densities in healthy,ocular hypertensive,and different stages of glaucomatous eyes 被引量:1
19
作者 Caner Ozturk Sirel Gur Gungor +2 位作者 Umit Eksioglu Almila Sarıgul Sezenoz Meric Colak 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2023年第12期2018-2026,共9页
AIM:To investigate vascular changes in different stages of glaucoma and to evaluate the role of optical coherence tomography angiography(OCTA)in the early diagnosis of glaucoma.METHODS:Glaucoma patients and healthy co... AIM:To investigate vascular changes in different stages of glaucoma and to evaluate the role of optical coherence tomography angiography(OCTA)in the early diagnosis of glaucoma.METHODS:Glaucoma patients and healthy controls(n=29 eyes)were investigated in this cross-sectional comparative study.Glaucoma patients were grouped as ocular hypertension(n=44 eyes),preperimetric glaucoma(PPG;n=32 eyes),early glaucoma(EG;n=35 eyes),moderate stage glaucoma(MG;n=36 eyes),and advanced glaucoma(AG;n=35 eyes).Peripapillary and macular vascular densities(VDs)of all participants were compared and correlations of VDs and retinal nerve fiber layer thickness(RNFLT),ganglion cell analysis(GCA),and visual field(VF)tests were evaluated.Area under the receiver operation characteristic curves(AUC)of the peripapillary and macular VD parameters were obtained.RESULTS:VD values decreased with the progression of glaucoma.Most peripapillary and macular VD parameters of PPG and EG groups were lower than healthy controls(P<0.001).There was no significant difference in RNFLT between the PPG and EG groups,but most peripapillary and macular VDs were found to be lower in EG group than in PPG group(P<0.05).In most disease group,VDs were significantly correlated with OCT parameters(P<0.001)and VF index(P<0.05).There were no significant correlations between VF and RNFLT indices in the AG group,but significant correlations were found between VF and VD values(P<0.05).AUC for discriminating between healthy and glaucomatous eyes were highest in whole image peripapillary VD(AUC:0.865,0.929,and 0.986,respectively in EG,MG,and AG groups).CONCLUSION:OCTA can be used in the early diagnosis of glaucoma and can be useful in follow-up of the advanced disease.In cases where limitations or suspicions in structural and functional tests are present,OCTA can be used as a supportive diagnostic test,both in EG and AG. 展开更多
关键词 GLAUCOMA optical coherence tomography angiography vascular density early diagnosis
原文传递
Clinical and Demograhical Characteristics of Patients with Maxillofacial Trauma in the Emergency Department 被引量:1
20
作者 Seval Komut Bedriye Mü +3 位作者 ge Sö nmez Ali Kemal Erenler Erdal Komut 《Open Journal of Emergency Medicine》 2019年第2期28-39,共12页
Objective: We aimed to investigate the clinical and demographical characteristics of patients admitted to the Emergency Department (ED) due to maxillofacial trauma (MFT). Methods: This sectional and retrospective stud... Objective: We aimed to investigate the clinical and demographical characteristics of patients admitted to the Emergency Department (ED) due to maxillofacial trauma (MFT). Methods: This sectional and retrospective study was conducted in Ankara Numune Education and Research Hospital ED between 1st March 2010 and 31st March 2017. Into the study, patients with MFT older than 15 years of age were included. Characteristics of patients were recorded. Patients’ characteristics were compared according to presence of fractures. Results: Mean age of the patients was 41.1 ± 18.0 years and a statistically significant relationship was determined between age and presence of fracture (p > 0.05). Of the patients, 74.5% was male and fracture presence was significantly more in males than females (p 0.05). Conclusion: The MFT is a pathology that either leads to its own, or can lead to life-threatening consequences as a result of additional organ injuries. The physician evaluating the patient should determine the MFT and additional pathologies and ensure that the interventions start as soon as possible. 展开更多
关键词 MAXILLOFACIAL TRAUMA EMERGENCY DEPARTMENT MAXILLOFACIAL FRACTURE
暂未订购
上一页 1 2 下一页 到第
使用帮助 返回顶部