Pediatric Cervical Spine Injuries and SCIWORA: WFNS Spine Committee Recommendations

Nikolay Konovalov,Nikolay Peev,Mehmet Zileli,Salman Sharif,Stanislav Kaprovoy,Stanislav Timonin 대한척추신경외과학회 2020 Neurospine Vol.17 No.4

Cervical trauma in children have variations from the adults mainly due to anatomic differences. An optimal diagnostic and treatment strategy is critical, particularly when there is a lack of standardized protocols for the management of such cases. This review paper examines the diagnostic and treatment options of pediatric cervical trauma and Spinal Cord Injury Without Radiographic Abnormality (SCIWORA). A literature search for the last 10 years were conducted using key words. Case reports, experimental studies, papers other than English language were excluded. Up-to-date information on pediatric cervical trauma and SCIWORA were reviewed and statements were produced to reach a consensus in 2 separate consensus meeting of WFNS Spine Committee. The statements were voted and reached a consensus using Delphi method. This review reflects different aspects of contemporary pediatric cervical trauma decision-making and treatment, and SCIWORA. The mainstay of SCIWORA treatment is nonsurgical with immobilization, avoidance of risky activities. Prognosis generally depends on the initial neurological status and magnetic resonance imaging. Due to a significant discrepancy in the literature on diagnostic and management, future randomized controlled trials are needed to aid in generating standardized protocols.

The role of development models in Japan’s and Korea’s relations with Central Asia: Discourses and practices

Nikolay Murashkin,Eriks Varpahovskis 한양대학교 아태지역연구센터 2022 Journal of Eurasian Studies Vol.13 No.2

This article examines the policies of development cooperation promoted by Japan and Korea in Central Asia, focussing on the roles of discourses treating Japan and Korea as potential non-Western models for the region’s development and modernisation in their relations with Central Asian states. We trace the evolution of relevant developmental approaches made by Japan and Korea, analysing discourses and practices of sharing experiences, as well as the key drivers behind those shifts, and we seek to locate these changes in the larger context of regional political economy and international relations. Furthermore, the article seeks to address the ideational and normative aspects of Japanese and Korean development cooperation in Central Asia. We conclude with a recap comparison of Japan’s and Korea’s sharing of development experiences.

Laparoscopic right posterior sectionectomy (LRPS) in semi prone position: surgical aspects and results

Nikolay BELEV,Panche KRASTEV,Radoslav PENKOV,Mihail SLAVCHEV 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.-

Sr2FeMoO6 nanosized compound with dielectric sheaths for magnetically sensitive spintronic devices

Nikolay Kalanda,김동현,Sergey Demyanov,유성조,Marta Yarmolich,Alexander Petrov,오석근 한국물리학회 2018 Current Applied Physics Vol.18 No.1

Single-phase agglomerated Sr2FeMoO6-d powders with the iron and molybdenum cations superstructural ordering of 88% were synthesized by sol-gel technique from the Sr(NO3)2 and Fe(NO3)3$9H2O solutions with pH ¼ 4. The ultrasound dispersion enabled us to obtain 75 nm grains. Powders were pressed with 4 GPa to receive the ceramics. The additional annealing at 700 K promoted the appearance of 7.5% SrMoO4 phase. The nanocomposite with dielectric sheaths around the grains was obtained. Magnetization temperature dependences in zero-field cooled mode revealed inhomogeneous magnetic states. At temperature below 19 K, the superparamagnetic state is observed. Temperature increase leads to a realization of the stable superparamagnetic and metastable ferrimagnetic states, blocked by magnetic anisotropy energy. The resistivity temperature dependences have the semiconducting conductivity type. The charge transfer due to the hopping conductivity on the localized states in the energy band near the Fermi level dominates at 260e300 K. At 130e200 K the charge transfer is realized by electrons tunneling through the energy barrier. The electrons inelastic tunneling on conducting channels between grains, through the localized states in the dielectic interlayer dominates at low temperatures. The resistivity decreases in magnetic fields and the negative tunneling magnetoresistive effect reaching 41% occurs.

Vertical Building Collapse Triggered by Loss of All Columns in the Ground Story−Last Line of Defense

Nikolay Lalkovski,Uwe Starossek 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.2

In multi-story buildings, one of the worst collapse types in terms of structural damage and loss of life is the pancake-type collapse, where some or all floors end up lying on top of each other like the layers of a pancake, with the floor contents crushed between them. Mostly observed after strong earthquakes, such collapses are triggered by loss of some or all vertical load bearing elements in some story−often the ground story. Once this occurs, the building part above the lost vertical elements− still intact−starts gaining downward velocity until it meets resistance from below. The ensuing impact forces often lead to collapse progression ending in total collapse. However, there are some examples of buildings in which the columns of an entire story failed and the collapse remained arrested after the subsequent impact. Such cases were observed in the 1995 Kobe earthquake and in the 1985 Mexico City earthquake. There have also been some failed controlled demolition attempts in which the intended total vertical collapse did not occur after letting a building collide with the ground by explosive removal of the vertical load bearing elements in the lowest stories. In an attempt to determine the factors which play the main role in arresting vertical collapse once initiated at the ground level, this paper studies the behavior of vertically falling multi-story building structures impacting a rigid surface representing the ground. A simplified analytical model of the problem is presented. Depending on the structural properties, several possible energy dissipation mechanisms, and−in case the collapse cannot be arrested at impact−collapse modes, are identified.

Thermal Plasma Spheroidization of High-Nitrogen Stainless Steel Powder Alloys Synthesized by Mechanical Alloying

Nikolay G. Razumov,Anatoly A. Popovich,QingSheng Wang 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.2

This paper presents the results of experimental studies on the treatment of Fe–23Cr–11Mn–1N high-nitrogen stainlesssteel powder alloys, synthesized by the mechanical alloying (MA) of elemental powders in the flow of a thermal plasma. Fe–23Cr–11Mn–1N high-nitrogen stainless steel powder alloys were prepared by MA in the attritor under an argon atmosphere. For spheroidization of Fe–23Cr–11Mn–1N high-nitrogen stainless steel powder alloys, the TekSphero 15 plantmanufactured by Tekna Plasma Systems Inc was used. The studies have shown the possibility of obtaining Fe–23Cr–11Mn–1N high-nitrogen spherical powders steel alloys from the powder obtained by MA. According to the results of a series ofexperiments, it was found that the results of plasma spheroidization of powders essentially depend on the size of the fractiondue to some difference in the particle shape and flowability, and on the gas regime of the plasma torch. It is established thatduring the plasma spheroidization process, some of the nitrogen leaves the alloy. The loss rate of nitrogen depends on thesize of the initial particles.

QCM based sensor for detecting volumetric properties of liquids

Nikolay Mukhin,Ralf Lucklum 한국물리학회 2019 Current Applied Physics Vol.19 No.6

We introduce a microacoustic sensor, which combines the quartz crystal microbalance, a liquid-filled cavity and an intermediate artificial layer with effective acoustic properties. Each of the three components fulfils a specific task. The quartz vibrates in its thickness shear mode and acts as source and detector of shear waves, which penetrate the intermediate artificial layer and excite a resonance in the liquid-filled cavity. Both the piezoelectric transducer and the liquid-filled cavity are high-Q resonators with well-adjusted resonance frequencies very close to each other. The intermediate artificial layer couples the two resonators in a distinct manner via control of the propagation of acoustic waves between the quartz crystal and the liquid-filled cavity layer. The origin of the sensor signal is a change of the resonance frequency of the liquid-filled cavity caused by variations of acoustic properties of the liquid analyte inside the cavity, first of all speed of sound. This resonance appears as second resonance peak in the admittance spectrum of the quartz crystal.

Making Sense of Medvedev’s Presidency: Russia Beyond the Looking Glass

Nikolay Petrov 동아시아재단 2008 Global Asia Vol.3 No.2

Hole Machining Based on Using an Incisive Built-Up Reamer

Nikolay Dudak,Aizhan Taskarina,Asylbek Kasenov,Galiya Itybaeva,Zhanara Mussina,Kairatolla Abishev,Ruslan Mukanov 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.10

This article deals with analyzing the existing cutting tools and ways of hole-making operations. The newly designed tool consists of four false teeth-incisors and the curved cutting edge. This tool provides the possibility to increase the hole quality (tolerance of size, surface roughness), to facilitate cutting and to increase tool life. Experimental studies related to hole processing were carried out by using a scanner. Reproducibility of the experiment was determined according to Cochran's criterion G. The obtained results were processed through the mathematical apparatus of the full factorial experiment of type 23. Based on relevant data measurements, the authors of this research built graphics based on the accuracy of diametric dimensions of the processed holes, spindle rotation frequency and cut feed, as well as on the dependence of surface roughness from technological factors (workpiece speed, feed and length). The graph shows that deviation of the diametric size increases with increase in feed and decreases with the speed increase; surface roughness is inversely proportional to workpiece speed. Precision machining of holes corresponds to 5-6 accuracy degree, which is higher by one or two orders of magnitude compared to using standard hole boring cutters and scans.

Some Problems of the Partial Discharge Burning Time

Nikolay V. Kinsht,Marat A. Katz 한국전기전자재료학회 2006 Transactions on Electrical and Electronic Material Vol.7 No.6

The problem of the partial discharge (PD) extinction is investigated. The transient process takes place in a small spherical inclusion which is located in the dielectric. Both the losses caused by polarization and ohmic losses as the dielectric parameters are taken into account. From the inclusion standpoint the dielectric is considered as an active two-pole element (equivalent generator) and inclusion represents by own current-voltage curve. PD extinction voltage was shown to depend on the polarization loss tangent.