Light-driven molecular current switch

S.Ne?p?rek,P.Toman,J.Sworakowski,J.Lipinski 한국물리학회 2002 Current Applied Physics Vol.2 No.4

A scheme of a light-driven current switch based on properties of a conducting polymer containing photochromic moietieschemically attached to the main chain is put forward. The idea is supported with results of 3D calculations of local states for chargecarriers formed in the vicinity of dipolar species in molecular materials, and with quantum chemical calculations.. 2002 Elsevier Science B.V. All rights reserved.

An Efficient Buffer Management Scheme for Deadlock-Free packet Routing

De Rek Pao 대한전자공학회 1993 JTC-CSCC : Joint Technical Conference on Circuits Vol.- No.-

An Enhanced Buddy Strategy for Subcube Recognition

De Rek Pao 대한전자공학회 1993 JTC-CSCC : Joint Technical Conference on Circuits Vol.- No.-

Neutrophil to Lymphocyte Ratio Predicts Left Ventricular Remodeling in Patients with ST Elevation Myocardial Infarction treated with Primary Percutaneous Intervention

Abdurrezzak Börekçi,Mustafa Gür,Caner Türkoğlu,Ahmet Oytun Baykan,Taner Şeker,Durmuş Yıldıray Şahin,Hazar Harbalıoğlu,Zafer Elbasan,Mustafa Topuz,Murat Çaylı 대한심장학회 2016 Korean Circulation Journal Vol.46 No.1

Background and Objectives: It has been demonstrated that the neutrophil/lymphocyte ratio (NLR) might be a useful marker to predict cardiovascular risk and events. We aimed to investigate the role of the NLR to predict ventricular remodeling (VR) in patients with anterior ST-elevation myocardial infarction (STEMI) who were treated with primary percutaneous coronary intervention. Subjects and Methods: We prospectively included 274 consecutive anterior STEMI patients. Echocardiography was performed during admission and at six months after myocardial infarction. VR was defined as at least 20% increase from baseline in left ventricular end- diastolic volume. Patients were divided into two groups according to their VR status: VR (n=67) and non-VR (n=207). Total and differential leukocyte count, N-terminal pro-brain natriuretic peptide (NT-proBNP) and other biochemical markers were measured at admission and 24 hours later. Results: Compared with the non-VR group, peak creatine kinase MB (CK-MB), NT-proBNP (24 h), neutrophil/lymphocyte ratio, presence of diabetes, no-reflow frequency and wall motion score index were significantly higher in patients with VR (p<0.05 for all). On multivariate logistic regression analysis, NLR (β=2.000, 95% confidence interval=1.577-2.537, p<0.001) as well as peak CK-MB, NT-proBNP (24 h), WMSI and diabetes incidence were associated with VR. The cutoff value of the neutrophil/lymphocyte ratio obtained by receiver operator characteristic curve analysis was 4.25 for the prediction of VR (sensitivity: 79 %, specificity: 74%). Conclusion: In patients with anterior STEMI, initial NLR and NT-proBNP measured 24 hours after admission may be useful for predicting adverse cardiovascular events including left VR.

Cyanobacterial Taxonomy: Current Problems and Prospects for the Integration of Traditional and Molecular Approaches [Review]

Jirˇí Komárek 한국조류학회I 2006 ALGAE Vol.21 No.4

The application of modern ecological, ultrastructural and molecular methods, aided by the cultivation of numerous cyanobacterial morphotypes, has substantially changed our knowledge of these organisms. It has led to major advances in cyanobacterial taxonomy and criteria for their phylogenetic classification. Molecular data provide basic criteria for cyanobacterial taxonomy; however, a correct phylogenetic system cannot be constructed without combining genetic data with knowledge from the previous 150 years research of cyanobacterial diversity. Thus, studies of morphological variation in nature, and modern morphological, ultrastructural, ecophysiological and biochemical characters need to be combined in a “polyphasic” approach. Taxonomic concepts for generic and infrageneric ranks are re-evaluated in light of combined phenotypic and molecular criteria. Despite their usefulness in experimental studies, the limitations of using strains from culture collections for systematic and omenclatural purposes is highlighted. The need for a continual revision of strain identification and proper nomenclatural practice associated with either the bacteriological or botanical codes is emphasized. Recent advances in taxonomy are highlighted in the context of prospects for understanding cyanobacterial diversity from natural habitats, and the evolutionary and adaptational processes that cyanobacteria undergo.

Conformation changes of polysilanes during the polaron formation

P.Toman,S.Ne?p?rek,J.W.Jang,C.E.Lee 한국물리학회 2002 Current Applied Physics Vol.2 No.4

Quantum mechanical studies of polaron formation in oligo[methyl(phenyl)silane] (OMPSi) was performed. The conformationsof the neutral, positively and negatively charged OMPSi were optimized by means of B3LYP method. For the evaluation of thesubstituent eects, the conformation of the unsubstituted oligosilane chain was also calculated. The negative polaron conformationshows a signicant stretching of the chain, whereas the positive polaron conformation is shrunk. This fact is associated with changesof electron density distribution. There is also a strong inuence of thep-conjugated substituent on the conformation of the negativepolaron. On the other hand, the inuence of the substituents on the conformation of the positive polaron is small. The absorptionspectra of the defect-free and polaron oligomers are discussed.. 2002 Elsevier Science B.V. All rights reserved.

CHARACTERIZATION OF BORON-DOPED CZ SILICON MATERIAL THROUGH SIMULATED NMOS THERMAL CYCLE

Cho, K. H.,Hahn, S. K.,Rek, Zofia U. 대한전자공학회 1989 ICVC : International Conference on VLSI and CAD Vol.1 No.1

The electrical property of lightly Boron-doped Czochralski silicon material was evaluated through simulated NMOS thermal cycle by employing eddy current resistivity measurement, spreading resistance measurement, four-point probe measurement, infrared absorption and synchrotron radiation section topography. The data show that the resistivity values measured by four-point probe methods tend to be unstable and/or shifted to higher values during the initial stage of bulk oxygen precipitation (shown by small distortion of pendello¨sung fringes). Only after almost complete disappearance of Pendello¨sung fringes, they become stable.

Assessment of Digital PCR as a Primary Reference Measurement Procedure to Support Advances in Precision Medicine

Whale, Alexandra S.,Jones, Gerwyn M.,Pavš,ič,, Jernej,Dreo, Tanja,Redshaw, Nicholas,Akyü,rek, Sema,Akgö,z, Mü,slü,m,Divieto, Carla,Sassi, Maria Paola,He, Hua-Jun,Cole, Kennet American Association for Clinical Chemistry, Inc. 2018 Clinical chemistry Vol.64 No.9

<P><B>BACKGROUND:</B></P><P>Genetic testing of tumor tissue and circulating cell-free DNA for somatic variants guides patient treatment of many cancers. Such measurements will be fundamental in the future support of precision medicine. However, there are currently no primary reference measurement procedures available for nucleic acid quantification that would support translation of tests for circulating tumor DNA into routine use.</P><P><B>METHODS:</B></P><P>We assessed the accuracy of digital PCR (dPCR) for copy number quantification of a frequently occurring single-nucleotide variant in colorectal cancer (<I>KRAS</I> c.35G>A, p.Gly12Asp, from hereon termed G12D) by evaluating potential sources of uncertainty that influence dPCR measurement.</P><P><B>RESULTS:</B></P><P>Concentration values for samples of <I>KRAS</I> G12D and wild-type plasmid templates varied by <1.2-fold when measured using 5 different assays with varying detection chemistry (hydrolysis, scorpion probes, and intercalating dyes) and <1.3-fold with 4 commercial dPCR platforms. Measurement trueness of a selected dPCR assay and platform was validated by comparison with an orthogonal method (inductively coupled plasma mass spectrometry). The candidate dPCR reference measurement procedure showed linear quantification over a wide range of copies per reaction and high repeatability and interlaboratory reproducibility (CV, 2%–8% and 5%–10%, respectively).</P><P><B>CONCLUSIONS:</B></P><P>This work validates dPCR as an SI-traceable reference measurement procedure based on enumeration and demonstrates how it can be applied for assignment of copy number concentration and fractional abundance values to DNA reference materials in an aqueous solution. High-accuracy measurements using dPCR will support the implementation and traceable standardization of molecular diagnostic procedures needed for advancements in precision medicine.</P>

Incidence of apical crack formation and propagation during removal of root canal filling materials with different engine driven nickel-titanium instruments

Taha Özyürek,Vildan Tek,Koray Yılmaz,Gülşah Uslu 대한치과보존학회 2017 Restorative Dentistry & Endodontics Vol.42 No.4

Objectives: To determine the incidence of crack formation and propagation in apical root dentin after retreatment procedures performed using ProTaper Universal Retreatment (PTR), Mtwo-R, ProTaper Next (PTN), and Twisted File Adaptive (TFA) systems. Materials and Methods: The study consisted of 120 extracted mandibular premolars. One millimeter from the apex of each tooth was ground perpendicular to the long axis of the tooth, and the apical surface was polished. Twenty teeth served as the negative control group. One hundred teeth were prepared, obturated, and then divided into 5 retreatment groups. The retreatment procedures were performed using the following files: PTR, Mtwo-R, PTN, TFA, and hand files. After filling material removal, apical enlargement was done using apical size 0.50 mm ProTaper Universal (PTU), Mtwo, PTN, TFA, and hand files. Digital images of the apical root surfaces were recorded before preparation, after preparation, after obturation, after filling removal, and after apical enlargement using a stereomicroscope. The images were then inspected for the presence of new apical cracks and crack propagation. Data were analyzed with χ2 tests using SPSS 21.0 software. Results: New cracks and crack propagation occurred in all the experimental groups during the retreatment process. Nickel-titanium rotary file systems caused significantly more apical crack formation and propagation than the hand files. The PTU system caused significantly more apical cracks than the other groups after the apical enlargement stage. Conclusions: This study showed that retreatment procedures and apical enlargement after the use of retreatment files can cause crack formation and propagation in apical dentin.

Effect of adaptive motion on cyclic fatigue resistance of a nickel titanium instrument designed for retreatment

Taha Özyürek,Koray Yılmaz and Gülşah Uslu 대한치과보존학회 2017 Restorative Dentistry & Endodontics Vol.42 No.1

Objectives: The aim of this study was to evaluate the cyclic fatigue resistance of the ProTaper Universal D1 file (Dentsply Maillefer) under continuous and adaptive motion. Materials and Methods: Forty ProTaper Universal D1 files were included in this study. The cyclic fatigue tests were performed using a dynamic cyclic fatigue testing device, which had an artificial stainless steel canal with a 60° angle of curvature and a 5 mm radius of curvature. The files were randomly divided into two groups (Group 1, Rotary motion; Group 2, Adaptive motion). The time to failure of the files were recorded in seconds. The number of cycles to failure (NCF) was calculated for each group. The data were statistically analyzed using Student’s t-test. The statistical significant level was set at p < 0.05. Results: The cyclic fatigue resistance of the adaptive motion group was significantly higher than the rotary motion group (p < 0.05). Conclusion: Within the limitations of the present study, the ‘Adaptive motion’ significantly increased the resistance of the ProTaper Universal D1 file to cyclic facture.