The Effect of Rod Pattern, Outrigger, and Multiple Screw-Rod Constructs for Surgical Stabilization of the 3-Column Destabilized Cervical Spine - A Biomechanical Analysis and Introduction of a Novel Technique

Sebastian Hartmann,Claudius Thomé,Anto Abramovic,Sara Lener,Werner Schmoelz,Juliane Koller,Heiko Koller 대한척추신경외과학회 2020 Neurospine Vol.17 No.3

Objective: Anterior-only reconstructions for cervical multilevel corpectomies are prone to fail under continuous mechanical loading. This study sought to define the mechanical characteristics of different constructs in reducing a range of motion (ROM) of the 3-column destabilized cervical spine, including posterior cobalt-chromium (CoCr)-rods, outrigger-rods (OGR), and a novel triple rod construct using lamina screws (6S3R). The clinical implications of biomechanical findings are discussed in depth from the perspective of the challenges surgeons face cervical deformity correction. Methods: Three-column deficient cervical spinal models were produced based on reconstructed computed tomography scans. The corpectomy defect between C3 and C7 end-level vertebrae was restored with anterior titanium (Ti) mesh-cage. The ROM was evaluated in a customized 6-degree of freedom spine tester. Tests were performed with different rod materials (Ti vs. CoCr), varying diameter rods (3.5 mm vs. 4.0 mm), with and without anterior plating, and using different construct patterns: bilateral rod fixation (standard-group), OGRgroup, and 6S3R-Group. Construct stability was expressed in changes and differences of ROM (°). Results: The largest reduction of ROM was noticed in the 6S3R-group compared to the standard- and the OGR-group. All differences observed were emphasized with an increasing number of corpectomy levels and if anterior plating was not added. For all simulated 1-, 2-, and 3-level corpectomy constructs, the OGR-group revealed decreased ROM for all motion directions compared to the standard-group. An increase of construct stiffness was also recorded for increased rod diameter (4.0 mm) and stiffer rod material (CoCr), though these effects lacked behind the more advanced construct pattern. Conclusion: A novel reconstructive technique, the 6S3R-construct, was shown to outperform all other constructs and might resemble a new standard of reference for advanced posterior fixation.

Human subcortical brain asymmetries in 15,847 people worldwide reveal effects of age and sex

Guadalupe, Tulio,Mathias, Samuel R.,vanErp, Theo G. M.,Whelan, Christopher D.,Zwiers, Marcel P.,Abe, Yoshinari,Abramovic, Lucija,Agartz, Ingrid,Andreassen, Ole A.,Arias-Vá,squez, Alejandro,Aribi Springer US 2017 Brain imaging and behavior Vol.11 No.5

<P>The two hemispheres of the human brain differ functionally and structurally. Despite over a century of research, the extent to which brain asymmetry is influenced by sex, handedness, age, and genetic factors is still controversial. Here we present the largest ever analysis of subcortical brain asymmetries, in a harmonized multi-site study using meta-analysis methods. Volumetric asymmetry of seven subcortical structures was assessed in 15,847 MRI scans from 52 datasets worldwide. There were sex differences in the asymmetry of the globus pallidus and putamen. Heritability estimates, derived from 1170 subjects belonging to 71 extended pedigrees, revealed that additive genetic factors influenced the asymmetry of these two structures and that of the hippocampus and thalamus. Handedness had no detectable effect on subcortical asymmetries, even in this unprecedented sample size, but the asymmetry of the putamen varied with age. Genetic drivers of asymmetry in the hippocampus, thalamus and basal ganglia may affect variability in human cognition, including susceptibility to psychiatric disorders.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1007/s11682-016-9629-z) contains supplementary material, which is available to authorized users.</P>

Soft-Switching and Efficient Power Transfer in Capacitive Wireless Systems with LCLC Compensation Networks

Eli Abramov,Mor Mordechai Peretz,Ilya Zeltser 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This study delineates the conditions for softswitching in capacitively-coupled resonant converters that are compensated with LCLC matching networks. Such converters’ setups are extremely popular in wireless capacitive power transfer(CPT) technology. The detailed analysis explores the intricate relationships between the parameters, operating conditions, and transfer characteristics. It reveals that by design of the compensation networks’ parameters according to the highest expected coupling capacitance, then zero-voltage switching (ZVS) conditions are achieved over the entire operation range. The results of the analysis further outline the necessary conditions for zero-current switching (ZCS) at turn off. Consequently, the system maintains soft-switching both at turn on and turn off, for all switches. This provides a significant potential enhancement of the power transfer and processing efficiency, in particular for applications of wireless energy where the operating frequency is very high. The theoretical analysis and predictions have been verified by simulations and experimentally. The simulation platform incorporates a simple and flexible cross-coupled model, also developed in this study, which is used to evaluate the results under various conditions. The experiments have been carried out on a LCLC capacitive-based WPT prototype operated in the MHz range, and examined through several air-gaps up to 120 mm. An excellent agreement has been obtained between the theoretical work, simulations and the experimental evidence.

Moscow as international financial center: Ideas, plans and perspectives

Dmitry Abramov,Stanislav Polezhaev,Mikhail Sherstnev 한양대학교 아태지역연구센터 2011 Journal of Eurasian Studies Vol.2 No.2

The paper provides an overview of the Russian official plans of development of the international financial center (based primarily in Moscow) and tries to stimulate the discussion on the critical assessment of the perspectives in order to outline the efficient ways to achieve this ambitious goal.

Studies of the Stability of Microcrystaline Silicon Bottom-Gate TFTs under Electrical Stress

Oumkelthoum Moustapha,Alexey Abramov,Y. Bonnassieux,P. Roca i Cabarroca,H. Y. Choe 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1

We present, in this paper, the stability results under bias stres of n-type microcrystaline silicon (μc-Si:H) botom- gate thin-film transistors (TFTs) with various intrinsic layer compositions (a single μc-Si layer or a dual intrinsic layer made of a-Si:H and μc-Si). TFTs were fabricated using the conventional amorphous silicon (a-Si:H) TFT proces(low temperature Plasma Enhanced Chemical Vapor Deposition). Our results suggest that the dual layer structure is advantageous in terms of procesing while keping good mobility and stability. After 24 hr of electrical stres the threshold voltage drift (ΔV<SUB>T</SUB>) was les than 0.2 V and mobility drift (Δμ) was about 8 %. In order to understand the causes of the instability, experimental analyses were performed; they showed that charge trapping at the interface was responsible for the degradation in the TFTs. Simulation of the impact of threshold voltage (V<SUB>T</SUB>) and the mobility drifts showed that a 1-V variation in V<SUB>T</SUB> induced a variation of 36 % in OLED curent and that a variation of 20 % in the mobility leads to a 23 % variation in the OLED curent.

Power-Switching Stokes Polarimeter for PCS radio path measurements

유재우,Victor I.Abramov,김우식,이정률 한국통신학회 1998 한국통신학회 학술대회논문집 Vol.17 No.3

Acute Cystitis Symptom Score questionnaire for measuring patient-reported outcomes in women with acute uncomplicated cystitis: Clinical validation as part of a phase III trial comparing antibiotic and nonantibiotic therapy

Jakhongir F. Alidjanov,Andre Overesch,Dimitri Abramov-Sommariva,Martina Hoeller,Hubert Steindl,Florian M. Wagenlehner,Kurt G. Naber 대한비뇨의학회 2020 Investigative and Clinical Urology Vol.61 No.5

Purpose: The Acute Cystitis Symptom Score (ACSS) used in a clinical trial comparing the phytodrug Canephron®N (BNO 1045) with an antibacterial agent (fosfomycin trometamol [FT]) in the treatment of acute uncomplicated cystitis (AC) in women was evaluated as a patient-reported outcome measure in a post hoc analysis. Materials and Methods: This double-blind, randomized, multicenter, phase III noninferiority trial was performed in 51 centers in Europe. The ACSS questionnaire was used to assess severity and course of symptoms. Results: The post hoc analysis included 325 patients treated with BNO 1045 and 332 patients treated with FT (total of 657 patients). The mean sum-scores of the ACSS-typical domain were comparable between groups on day 1 (BNO 1045: 10.2; FT: 10.1), and then decreased on day 4 (BNO 1045: 5.1; FT: 4.5), at end of treatment on day 8 (BNO 1045: 2.1; FT: 2.1), and at late follow-up on day 38 (BNO 1045: 0.8; FT: 0.9). Predefined thresholds using the scoring system of the ACSS could be established and validated to define “clinical cure.”Conclusions: Evaluating not only antibacterial but also nonantibacterial agents indicated for the treatment of AC in women, clinical criteria for diagnostics, and measures of patient-reported outcomes are more important as main objectives than microbiological criteria. In this post hoc evaluation, we showed that the ACSS questionnaire, validated in several languages, has the potential to be used as a suitable instrument for diagnostics and patient-reported outcomes in well-designed, international, clinical studies investigating different treatment modalities of uncomplicated urinary tract infections.

Synthesis and photophysical properties of copolyfluorenes for light-emitting applications: Spectroscopic experimental study and theoretical DFT consideration

Smyslov, Ruslan Yu,Tomilin, Felix N.,Shchugoreva, Irina A.,Nosova, Galina I.,Zhukova, Elena V.,Litvinova, Larisa S.,Yakimansky, Alexander V.,Kolesnikov, Ilya,Abramov, Igor G.,Ovchinnikov, Sergei G.,Av Elsevier 2019 Polymer Vol.168 No.-

<P><B>Abstract</B></P> <P>Using Suzuki and Yamamoto coupling reactions, copoly-(9,9-dioctylfluorenes) (<B>CPF</B>) were synthesized and compared regarding their photophysical properties using the spectroscopic and <I>ab initio</I> DFT approaches. The CPFs were functionalized by benzo [2,3,5] thiadiazole (<B>BT</B>) or carbazole-3,6-diyl (3,6-Cz). The latter was used to introduce different luminophore fragments, including Nile red and 4-pyrrolidinyl-1,8-naphthalimide derivatives. The effect of the two synthesis techniques on the polymer microstructure, the influence of embedding of 3,6-Cz moieties in the polymer backbone on polymer structuring, and the impact of the end groups like novel quinoxaline-containing compounds on the luminescent properties of CPFs were investigated. By comparing electron density distribution using the <I>ab initio</I> DFT approach with photoluminescence, it was shown that Suzuki reaction provides a chain microstructure with individual BT fragments separated by 9,9-dioctylfluorene monomeric units, while Yamamoto reaction leads to the blocks of BT units. This effect leads to different CPF photophysical properties (absorption and emission spectra).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Light-emitted copolyfluorenes were obtained using Suzuki and Yamamoto reactions. </LI> <LI> Yamamoto coupling leads in the microblock chain structure of conjugated polymer. </LI> <LI> Suzuki coupling allows the alternating comonomeric copolyfluorene chain. </LI> <LI> End groups rule photoluminescence properties of copolyfluorenes. </LI> <LI> Naphthalbenzimidazole group provides FRET from fluorene to Nile red. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>