bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Rate of Elastic-plastic Crack Propagation of Heterogeneous Metal Welded Joints in Nuclear Power
Authors: Li G B , Xue H , Bi Y Q , Zhang L
Published: February 2020

In the high-temperature water environment of nuclear power, austenitic stainless steel, nickel-based alloy materials and welded joints composed thereof are the key locations for environmental cracking (EAC) problems such as stress corrosion cracking (SCC). In order to understand the crack propagation behavior and expansion rate of welded joints under the condition of abrupt and heterogeneous material properties of welded joints, this paper uses the extended finite element technique (XFEM) in the large nonlinear finite element software ABAQUS, based on the elastoplastic material model. Under the condition of welding residual stress field, the effects of different initial crack length and strength mismatch ratio on the crack growth rate of stress corrosion crack under constant load were studied. The results show that the SCC crack growth rate increases with the increase of the initial crack length. When the crack length of the initial welded joint is constant, different mismatch ratio has a certain effect on the crack growth rate. In the low ratio range(less than 1), the crack growth rate also increase if the strength mismatch ratio increase. but the crack growth rate is gradually reduce in high ratio range(more than 1). This indicates that the mismatch ratio of 1 is favorable for crack propagation, and the larger the mismatch ratio, the crack propagation is hindered.
Thermodynamic Modeling and Simulation Analysis of Double-tube Damper
Authors: Chen Yijie , Gao Xiaodong , Wan Yiqiang , Han Xiaoling , Dai Jianjian
Published: February 2020

At present, most of the special vehicles were also designed with a double-tube damper, which was characterized by convenient installation and low cost. However, due to the design of the oil storage cavity outside the working cylinder, the heat dissipation effect was not ideal, and the working temperature of the oil too high will accelerate the aging of the sealing member, which was also a key problem that plagues the reliability design of the damper. Aiming at the structural characteristics of the double-tube damper, the heat generation mechanism and energy conversion research of the oil were carried out, and the heat transfer coefficient and heat conduction equation of the inner and outer surfaces of the cylinder were derived. The comprehensive heat transfer expression was solved for the working medium, and the thermodynamic model of the double-tube damper was constructed. Finally, the simulation analysis of the influence of different structural parameters on the heat balance temperature were carried out, which could effectively guide the design and development of the damper.
Molecular Dynamics Simulation of Rarefaction Effect on Shear-driven Gas Flow in Nanochannels
Authors: Zhang Ye , Zhang Ran , Xie Wenjia , Li Hua
Published: February 2020

The nanoscale gas flow at normal temperature and pressure varies from the slip flow regime to the transition regime, of which the character length changes across several nanometers to several thousand nanometers. The difference in the degree of rarefaction leads to different rules of the flow in nanochannels. In order to study the influence of rare gas effect on the nanoscale gas flow, we use three-dimensional molecular dynamics method to simulate the shear flow confined by two parallel plate under different Knudsen numbers, and then obtain the distribution of flow velocity, density, normal stress and shear stress, thus calculating and analyzing the variation of the tangential momentum accommodation coefficient. Counting the gas molecules according to the velocity with positive and negative values respectively, we find that the gas flow is decomposed into two independent shear flows, which indicates strong non-equilibrium characteristics in the nanochannel.
Research on Construction Method, Risk Identification and Evaluation Technology of UHV AC Composite Cross Arm Pole and Tower
Authors: Hu Chunhua , Wan Jiancheng , Jiang Ming , Hao Yujing
Published: February 2020

The research on construction method of UHV AC composite cross arm pole and tower mainly combines the material and structural characteristics of composite cross arm insulator, analyzes the danger sources which may cause damage to construction links such as packaging, transportation, storage, construction hauling, lifting and installation, and then this paper conducts evaluation, and proposes corresponding construction measures, thus forming the construction technical scheme of UHV AC composite cross arm pole and tower. This paper conducts analysis and assessment to the risk (danger source) of damage to composite cross arm insulator during the construction by utilizing the risk evaluation method, and then proposes corresponding construction full-protection measures and counter measures targeting the assessment results.
Density and microstructural investigation of Ce:YAG ceramic subjected to powerful ultrasonic treatment during the compaction process
Authors: Paygin V D , Dvilis E S , Valiev D T , Khasanov O L , Stepanov S A , Vaganov V A , Alishin T R , Kalashnikov M P
Published: February 2020

The aim of the present work was to investigate the effect of the applied pressure, sintering temperature and ultrasonic treatment during the pressing process on the density and microstructure of translucent ceramics based on yttrium-aluminum garnet doped with cerium ions (Ce: YAG) obtained by conventional sintering of pressed compacts. The optimization of manufacturing conditions of the ceramics was carried out. It was shown that the ultrasonic treatment of initial powder in optimal sintering conditions leads to an increase in the relative density and grain size and decrease in the pore size of the sintered ceramics.
Effect of thermomechanical impacts on the deformation of thin polyimide films at uniaxial tension
Authors: Kupchishin A I , Taipova B G , Niyazov M N , Lisitsyn V M , Voronova N A
Published: February 2020

Thermomechanical studies of the dependence of deformation (ε) on time (t) and temperature (T) for various static stresses in polyimide under uniaxial tension were carried out. Temporal deformation curves for static stresses in the range from 75 to 110 MPa consist of two stages: 1 – increase; 2 – exit to saturation, which is associated with a change in the nature of structural transformations of macromolecules, due to the action of the static stresses. An increase in temperature and voltage leads to an increase in the dependence ε (T). This is due to the intensification of the processes of structuring macromolecules with increasing temperature and are supplemented by processes of breaking bonds between macromolecules, which increase the strain rate. Experimental data are described in terms of exponential and linear models.
Study on formation of aluminum alloy thin wall produced with WAAM method under various thermal conditions
Authors: Kisarev A V , Kobernik N V
Published: February 2020

The study reveals some formation aspects of a thin walls made by WAAM technology. The series of experiments about thin wall deposition in a various thermal condition was carried out. Temperature field finite element model was developed and solved under the giving conditions. Experimental results were treated after metallographic analysis, functional dependences of the width and height of the deposited layer by the temperature of the previous layer were constructed. In a range of 30-300 C sublayer temperature, layer height and width values show linear functional dependencies by sublayer temperature.
Numerical model of a hollow cathode arc discharge formation in vacuum
Authors: Permyakov G L , Trushnikov D N , Mindibaev M K , Koleva E G
Published: February 2020

Industrial application of hollow cathode arc (HCA) discharge necessitates understanding the processes of interaction between the plasma and the cathode and the anode, as well as related processes. The first step is to study the formation process of HCA discharge in vacuum with the micro-flow of plasma-forming gas through the hollow cathode. In this work presents a two-dimensional model describing the related processes of transfer of charged particles and the movement of plasma-forming gas flows. Electron density and mean electron energy are calculated by solving the drift-diffusion equations. The mass transfer equation for a multicomponent mixture is used to describe the mass transfer of heavy plasma particles. To calculate the electric field strength the Poisson equation is used. The emission of secondary electrons from the inner surface of the cathode is taken into account. The boundary conditions take into account the loss of charge as a result of chaotic motion and its occurrence due to thermal emission effects. The gas flow is determined by collisions and diffuse re-reflection from all surfaces assumed in accordance with Knudsen’s law. Calculations of plasma formation and the movement of plasma-forming gas flows were performed using the simulation package COMSOL Multiphysics.
Analysis of failures of bearings of axle box unit with polyamide cages and prospects of increasing their service life
Authors: Butorin D V , Filippenko N G , Livshits A V , Popov S I
Published: February 2020

The article analyzes failures of bearings of the axle box unit with polyamide cages and investigates the influence of climatic conditions on operational characteristics of cages. It is determined that the greatest number of defects during the operation of polyamide cages occurs in the following periods: summer-autumn, autumn, winter, winter-spring, spring. The revealed dependence of the operational properties of polyamide samples on weather and climatic conditions in different seasons of the year allows predicting the change in the operational characteristics of the cage and taking measures to restore and improve them. The authors proposed a method of restoration and improvement of operational properties of cages by processing them using a technique of high-frequency electrothermy. Full-scale tests showed the high efficiency of the proposed method, expressed in reducing the weight of the samples as a result of moisture removal, as well as in an ambiguous change in strength properties. Their ambiguity lies in the fact that cages differently restore their original hardness indicators after processing. And in the periods corresponding to winter and winter-spring, it was possible to restore strength indicators to a level even above the original one. For high-frequency processing of polyamide cages, a device has been developed that provides the required coverage of the workpiece electrodes on the upper, lower and inner side surfaces of the partitions. The test of the developed device made is possible to achieve the desired results, expressed in a significant decrease in the relative humidity of the cages and an increase in their strength characteristics by 7.6% of the initial level. All this confirms the practical importance and progressiveness of the developments presented in the work.
Determination of electromagnetic effects of electric traction networks on pipelines
Authors: Cherepanov A V , Kryukov A E
Published: February 2020

The article presents the simulation results of electromagnetic effects of a 25 kV electric traction network on a steel pipeline with a pipe diameter of 250 mm. It is shown that a pipeline with insulating pipe coatings can induce stresses dangerous to operating personnel. At certain points of the pipeline, grounded on both sides, the magnitude of the induced voltage can reach 116 V with an approach width of 100 meters. Therefore, it is required to develop and implement special measures to protect operating personnel. With an increase in the approach width to 400 m, the maximum values of the induced voltages did not exceed the permissible level. In modes of short circuits in the electric traction network, the induced voltages in the pipeline may briefly exceed 500 V. The highest voltages are observed at points located near the short circuit point. In case of short circuits at the terminals of the traction substations, the magnitudes of the induced voltages are reduced to 75 V. To reduce the induced voltages, the following measures can be assumed: reducing the length of parallel passage sections of pipeline and railway, increasing the approach width, installing additional groundings. During the operation of the structure, the magnitude of the “pipe-to-ground” transition resistance may decrease, which will result in a decrease in induced voltages.
Study of thermal zones in a heating collector of a traction motor NB-418 K6
Authors: Chuiko A D , Christosenkov S A
Published: February 2020

The article provides the data about functional dependencies affecting the heating characteristic of the traction electric motor (faulty soldering in the riser winding). Studies have shown the functional dependence of the temperature drop along the length of the riser (with the coefficient 0.95 %) that allows determining the functional dependence of the riser temperature on its length.
Methodology for evaluating of the interaction of wagons and path on the mountain-gorge areas
Authors: Yu Ermolenko I , Zheleznyak V N
Published: February 2020

In recent years, the number of rolling stock derailments, especially unladen wagons has begun to increase on railways located in hard geographical and climatic conditions in Eastern Siberia. In view of this, we propose the methods for evaluation of the interaction of wagons and railroad track for safety train movement and determination of appropriate schedule for train operation.
Simulation of an integrated public transport system by the example of a compact city
Authors: Lebedeva O , Poltavskaya Ju , Gozbenko V
Published: February 2020

The effectiveness of the transport network depends on the coherence of all message options. Suburban rail transportation and route bus service are travel options often used in medium and large cities in developed and developing countries. Integrating these two travel options reduces total travel time. The study will consider the application of the operational integration model of suburban trains and urban public transport. The model includes two submodels: routing and planning. In the routing submodels, public transport bus routes are generated that pass through the railway station. The planning sub-model will allow developing suburban train schedules with the optimal coordination of timetables for urban bus routes. As an example, the railway station Angarsk and the urban route network are considered. Bus transportation is coordinated with the existing railway timetable for the arrival of local trains. Genetic algorithms are robust optimization techniques and can be used in planning submodels. The result of the study is to determine the routes that require changes in the timetable, taking into account the arriving trains.
Calculations of efficiency in implementing progressive mold forming methods
Authors: Yu Konyuhov V , Gladkih A M , Galyautdinov I I , Shchadova E I
Published: February 2020

The article provides a classical prime cost accounting, outlining steps for calculating the cost at production site. The calculations compare two methods of manufacturing titanium parts for the aviation industry. The first method uses the mold forming by drop forging and the second one uses a modern superplastic manufacturing technology. This comparative calculation will determine the price of production of one set of parts for the SU-30. The considered methods of manufacturing parts will show the prime cost of production and will draw conclusions on further cooperation between Irkutsk Aviation Plant and Irkutsk State Technical University in the field of titanium products mold forming for modern aircraft.
Information systems of passenger transportation forecast in Transbaikal region
Authors: Kriklevskaya L Y , Kuklina O K , Mihailova E A , Yahina A S
Published: February 2020

The paper is concerned with the qualitative assessment of socio-economic development of transport industry of the region made with a help of information systems and mathematical methods. The object of this study is a railway transportation system in Transbaikal region. The research was made on the basis of a priori and posteriori approach with the use of recessionary analysis and correlation. The research of basic trends in socio-economic development of Transbaikal region during a long period of time (10 years) comprising the periods of growth and stagnation made it possible to reveal a set of models which affects the volume of transportation. This will help to forecast a strategy of development of Transbaikal region. The article contains the results of empirical study on interconnection between a set of factors and a volume of passenger transportation in Transbaikal region.
Research on ecologically safe flokulants in clay fluid fluids
Authors: Averkina E V , Shakirova E V , Butakova L A
Published: February 2020

Currently, a large number of flocculants differing in properties and composition and working differently in various conditions is manufactured. Drilling fluids are complex systems differing in component composition, thus, it is not possible to recommend a universal flocculant. The present study carries out the analysis with the use of two methods with the objective to assess reagents’ flocculating ability. Having analyzed the results obtained, the following conclusions can be drawn: the reagents BENEX, BENTOPLUS and DRB-9 can be used to increase the clay solution viscosity provided that the additives BENTOPLUS and DRB-9 do not exceed the concentration of 0.2 kg/m3; in a concentration of up to 0.1 kg/m3 flocculant SPECFLOC A 7950-20 can be used to increase a clay solution viscosity, at a concentration of 0.2 and 0.3 kg/m3 the additive affects a drilling fluid mainly as a flocculant, thus, reducing the static shear stress of the solution and increasing filtrate flow. If dynamic shear stress is the only determining parameter in drilling with drilling fluid with SPECFLOC N6919 additive, then it can be recommended for being used. In all other cases additional research is required.
Advanced technologies of international cargo correspondence in railway transport
Authors: Zubkov V V , Sirina N F
Published: February 2020

The technologies of formation of transportation documents and preliminary informing in the international traffic are the primary directions of improvement of information technologies of interstate transfer points both for the information systems of state control and regulation and for the information systems of the subjects of transportation services. In the railway transport system of the Russian Federation the model of formation of transportation documents and preliminary information has a number of distinctive features from the existing model of the world practice. The article analyzes and determines the possibility of development and interaction of information systems of state authorities, owners and consumers of transport services in a single information space, methods of their consolidation and integration into international transport corridors. Automation of technological operations on processing of transport documents and preliminary informing by creation and introduction of innovative developments in the field of management of process of technological interaction of participants of transport - providing services is considered. The automated system of processing of transportation documents for imported cargo with barcoding and the automated system of informing cargo owners about the approaching expiration date of the phytosanitary certificate are presented and proposed for use at the interstate junction points. The proposed information systems improve and optimize these technologies, accelerate trade turnover and ensure the implementation of projects for the development of a common information space in the segment of international traffic and the development of transport international relations in general. The systems have undergone states registration.
Coordination of the microwave module used in the Doppler meter of the velocity vector components
Authors: Trushnikov V E , Valitov R R , Grishin M V
Published: February 2020

The article describes a method for coordinating the microwave path and verifying the microwave module of the DMVC. The method for coordinating and adjusting the microwave module helps measure and evaluate characteristics of the device to confirm compliance with the DMVC requirements.
Analysis of stresses and deformations of elements of axle boxes and improvement of their shape
Authors: Tsvik L B , Tarmaev A A , Bocharov I S , Eremeev V K
Published: February 2020

The development of constructive recommendations aimed at increasing the service life of roller bearings of axle boxes of railway cars is described. The elastic volumetric stress-strain state of the bearing elements of the bearings under consideration is analyzed. Numerical analysis of the corresponding mathematical models was carried out using the finite element method in the NX NASTRAN software environment. It is shown that near the edge of the roller with chamfer-rounding, a stress concentration arises, caused by insufficient smoothness of the contour line of the axial section of the roller. It is noted that this concentration is caused by the fact that the line of the contour under consideration has a finite specified curvature in the section corresponding to the chamfer and almost zero curvature in the adjacent straight section corresponding to the cylindrical surface of the roller. It is shown that the use of smoother contour lines for the marginal zone of a roller more than doubles the maximum value of the stress intensity in the boundary zone under consideration and accordingly increases the cyclic life of the bearing. The proposed smoothing of the line of the considered circuit allows one not only to unload the edge of the roller but also to reduce the contact pressure in its middle part. At the same time the stress-strain state of the roller becomes more uniform by increasing the smoothness of the contour line in the area of the roller’s edge and simultaneously reducing the degree of bombing (barrel-shaped) its cylindrical surface.
Assessment of contribution of human factor and factors of material-technical supply to safety risks due to poor repair and technology
Authors: Verevkina O I
Published: February 2020

The paper discusses the method of assessment and analysis of functional risks within the infrastructure of the railway transport network. The basis of the method is laid down in [1-4], but the risk assessment subsystem was not described due to poor repair. This paper will try to fill this gap. A general diagram of traffic safety risks by factors was developed. The method of transforming the probability function of repair rules violation into the probability of traffic safety violation due to some repair is proposed. For this purpose, the problem of minimizing the disparity in non-linear equations determining scaled factors of traffic safety violation (TSV) due to re-pair is solved. The calculation results at the level of linear enterprise are presented.
US dark-matter detector heads underground
Authors: Banks Michael
Published: February 2020

The main component of the LUX-ZEPLIN dark-matter detector has been installed at the Sanford Underground Research Facility in Lead, South Dakota.
Student mentoring needs recognition
Authors: Gwynne Peter
Published: February 2020

Effective mentoring of graduate and undergraduate students in scientific fields plays a key role in their professional success but more needs to be done to make sure it is better recognized and rewarded within US higher education.
Harnessing the wind
Authors: Harris Margaret
Published: February 2020

From Caribbean islands to the windswept coasts of northern Europe, a new way of generating renewable energy is taking shape. But will it ever reach the mainstream energy sector? Margaret Harris explores the promise and the challenges of airborne wind energy
A relative journey
Authors: Randall Ian
Published: February 2020

A trope that has indelibly attached itself to Albert Einstein’s theory of relativity, since its public debut, is that few individuals – save the great physicist himself – are fully able to grasp the science, despite it attracting interest from all quarters. Reading his new book, Einstein on the Run: How Britain Saved the World's Greatest Scientist, one cannot help but feel that author Andrew Robinson's panoptic grasp of his world-renowned subject has by coincidence taken on a somewhat similarly formidable but irresistible appeal.
Beyond biology
Authors: Chamary JV
Published: February 2020

Race is a social construct and not a scientific concept, so why do many people still believe it has some basis in biology? That’s the big topic that science journalist Angela Saini explores in her latest book Superior: the Return of Race Science.
Use of Exclusive Enteral Formula Diet as Adjunctive Therapy for Treatment of a Crohn’s Disease Flare
Authors: Teigen Levi M , Johnson Abigail J , Shmidt Eugenia , Vaughn Byron P
Published: February 2020

Introduction

We report the case of an adult patient who achieved remission of a Crohn’s disease flare after treatment with exclusive enteral nutrition as adjunctive therapy to medication.

Case Report

A 46-year-old man with severe, stricturing Crohn’s presented for severe abdominal pain and weight loss; estimated Crohn’s Disease Activity Index score greater than 300. Antibiotics, vedolizumab, budesonide, and exclusive enteral nutrition diet were instituted. Approximately 30 days later, his Crohn’s Disease Activity Index score improved to 170.

Discussion

This case illustrates the possible utility of an exclusive enteral formula diet as an adjunct to medication to induce remission of a Crohn’s disease flare.
Robotic mitral valve repair for rheumatic mitral stenosis and regurgitation: a case report
Authors: Yajima Shin , Fukushima Satsuki , Kakuta Takashi , Fujita Tomoyuki
Published: February 2020

Background

Rheumatic mitral valve (MV) disease is the major cause of congestive cardiac failure in children and young adults, particularly in developing countries. Mitral valve repair with minimum prosthetic material is the gold standard treatment for this condition. However, MV repair for rheumatic MV disease is known to be technically demanding.

Case summary

A 27-year-old woman without a history of cardiac disease presented with dyspnoea on exertion. Echocardiography revealed rheumatic severe mitral stenosis and regurgitation, with thickening of the bileaflets, doming of the anterior leaflet, shortening of the posterior leaflet, fusions of the lateral and particularly the medial commissure, and enlargement of the mitral annulus. We successfully performed robot-assisted MV repair with bicommissural release, patch augmentation of the two leaflets, and implantation of an originally sized partial band.

Discussion

Robotic MV repair can contribute to precise valve inspection and operative procedures. This approach seems feasible for complex rheumatic MV disease particularly in young patients.
Determination of Chloramphenicol and Nitrofuran Metabolites in Cobia, Croaker, and Shrimp Using Microwave-Assisted Derivatization, Automated SPE, and LC-MS/MS–Results from a U.S. Food and Drug Administration Level Three Inter-Laboratory Study
Authors: Veach Brian T ,   Collaborators, Bandara N , Broadaway B , Casey C , Fong A , Karmakar A , Mayweather M , Morara A , Williams N , Wright B , Ye L
Published: February 2020

Background

An interlaboratory study was conducted to test a published, peer-reviewed manuscript in the Journal of AOAC INTERNATIONAL Vol 98, No. 3, 2015, “Quantitation of Chloramphenicol and Nitrofuran Metabolites in Aquaculture Products Using Microwave-Assisted Derivatization, Automated Solid-Phase Extraction, and LC-MS/MS.”

Objective

The purpose of this study was to demonstrate the performance of the method in shrimp, cobia, and croaker matrices.

Method

Three U.S. Food and Drug Administration laboratories participated in the collaborative study. The laboratories tested matrix blanks and laboratory-fortified matrix blanks at various levels in three separate matrices. The method evaluation included determination of the LOQ, accuracy, and precision.

Results

The reproducibility and repeatability of the RSD, % levels for matrix spikes fortified below the action level were < 10% for all residues in shrimp, < 13% for all residues in cobia except for 3-amino-2-oxazolidinone which was ≤ 22%, and < 16% for croaker. The RSD, % levels for all other spikes in the study were < 14%. Average percent recoveries for all matrices ranged from 81.6% – 102%.

Conclusions

The study demonstrated that the method is acceptable for use for the combined determination of chloramphenicol and nitrofuran metabolites in the study matrices.

Highlights

The study showed acceptable quantitation for the high-throughput chloramphenicol and nitrofuran metabolites method.
Who Convened the First Council of Nicaea: Constantine or Ossius?
Authors: Fernández Samuel
Published: February 2020

The ancient church historians affirmed that it was Constantine himself who convened the Council of Nicaea. However, a chronological examination of the contemporary documents shows that the convocation of Nicaea was quite different. This essay aims to examine the origin of the idea of holding the Nicene council. According to the available data, Ossius of Cordoba convened the great episcopal council that was to be held at Ancyra but ultimately occurred in Nicaea. Although Constantine’s participation was decisive for the success of Nicaea, the study of the historical sources indicates that the original idea of holding the council that ultimately occurred at Nicaea must be credited to Ossius.
Effect of Age on Longitudinal Changes in Symptoms, Function, and Outcome in the First Year After Mild-Moderate Traumatic Brain Injury
Authors: Thompson Hilaire J. , Rivara Frederick P. , Wang Jin
Published: February 2020

OBJECTIVE: The aim of this study was to describe and compare the recovery and disability trajectory at 1 year post injury for younger and older adults with traumatic brain injury (TBI). METHODS: This was a prospective longitudinal cohort study. Individuals 21 years and older with mild to moderate TBI were recruited from the emergency department (n = 33). We measured symptoms, function (Glasgow Outcome Scale-Extended, Functional Status Examination), and health-related quality of life (HRQOL) at 1 week and 1, 3, 6, and 12 months post injury. RESULTS: Whereas the total number of symptoms does not differ between younger and older adults after TBI, the specific constellation of symptoms experienced does. Older adults are more likely to experience physical symptoms such as fatigue, balance, and coordination problems as well as complain of being bothered by noise. Younger adults, in contrast, endorse more psychological symptoms such as anxiety. Functioning as measured by the Glasgow Outcome Scale-Extended and Functional Status Examination was lower in older adults at 1 year post injury. Physical HRQOL was consistently poorer in the year post injury among older adults compared with younger adults after TBI. Mental HRQOL, in contrast, was higher in older adults post TBI at 1 year. CONCLUSIONS: During the first year post TBI, older adults report different symptom clusters than do younger adults post TBI. To foster improved recovery and HRQOL in the older adult post TBI, nursing management strategies should focus on balance, coordination, and energy conservation.
Nurses' Knowledge of Opioids
Authors: Kaiser Jennifer
Published: February 2020

Background:

The opioid crisis has influenced practice changes to mitigate risks to patients receiving opioids. It is essential that nurses understand contemporary guidelines to provide safe patient care for patients receiving opioids.

Purpose:

This study was designed to assess general knowledge of opioids among nurses in nonprescribing patient care roles.

Methods:

A survey was developed, validated, and deployed to 564 nurses in a large hospital system.

Results:

Nurses had strong knowledge of basic pharmacology, the conjunctive use of nonopioids for pain relief, and differences in analgesia for chronic versus acute pain. Opportunity for education included risk factors for opioid-related adverse events, medication combinations, differences in opioid tolerant and opioid-naïve patients, and recognition and management of overdose.

Conclusions:

Results of this study can be used to guide continuing education and academic curricula to ensure nurses are equipped with the key knowledge to provide safe quality clinical care and patient education.
Giant Cell Tumor of Bone With Cartilage Matrix
Authors: Brčić Iva , Yamani Feisal , Inwards Carrie Y. , Sumathi Vaiyapuri , Dodd Leslie , Kreiger Portia A. , Sittampalam Kesavan , Allred Ted R. , Kashofer Karl , Liegl-Atzwanger Bernadette , Kerr Darcy A. , Nielsen G.P. , Rosenberg Andrew E.
Published: February 2020

Giant cell tumor of bone (GCT) is a benign locally aggressive neoplasm composed of mononuclear cells admixed with innumerable osteoclast-type giant cells. H3F3A gene mutations producing mutant histone protein product H3.3 have been identified in 96% of GCT; mutant H3.3 is reliably demonstrated by immunohistochemistry. GCT may contain woven bone and rarely, neoplastic cartilage nodules which causes diagnostic challenges with aggressive neoplasms such as osteosarcoma. We describe the features of GCT with cartilage matrix and report the next-generation sequencing findings in a subset of tumors. Seventeen cases of GCT with cartilage matrix form the cohort: 7 males and 10 females, 13 to 55 (mean: 25) years old. Tumors involved the fibula (6), femur (6), and patella, tibia, humerus, S1, and scapula (1 case each). Tumors were radiolucent, circumscribed, lytic, and expansile. All contained classic GCT, foci of cartilage matrix, and trabeculae of woven bone. Immunohistochemistry showed diffuse staining for H3.3 in 9/9 cases and 1 case was positive for S100 and SOX9 in the cartilage areas. Next-generation sequencing showed a mutation in the H3F3A gene in 6/6 cases. On follow-up, 2 patients who underwent resection showed no disease after 12, and 7 months, respectively. Three patients had recurrences 10, 12, and 27 months after curettage; there were no metastases. GCT with cartilage matrix is uncommon. The cartilage matrix is associated with woven bone suggesting the neoplastic cells may differentiate into chondrocyte-like and osteoblast-like cells. Recognition of this neoplasm is important to prevent misdiagnosis and overtreatment of affected patients.
Vitamin C and thiamine are associated with lower mortality in sepsis
Authors: Byerly Saskya , Parreco Joshua P. , Soe-Lin Hahn , Parks Jonathan J. , Lee Eugenia E. , Shnaydman Ilya , Mantero Alejandro , Yeh D. Dante , Namias Nicholas , Rattan Rishi
Published: February 2020

BACKGROUND

The efficacy of vitamin C (VitC) and thiamine (THMN) in patients admitted to the intensive care unit (ICU) with sepsis is unclear. The purpose of this study was to evaluate the effect of VitC and THMN on mortality and lactate clearance in ICU patients. We hypothesized that survival and lactate clearance would be improved when treated with thiamine and/or VitC.

METHODS

The Philips eICU database version 2.0 was queried for patients admitted to the ICU in 2014 to 2015 for 48 hours or longer and patients with sepsis and an elevated lactate of 2.0 mmol/L or greater. Subjects were categorized according to the receipt of VitC, THMN, both, or neither. The primary outcome was in-hospital mortality. Secondary outcome was lactate clearance defined as lactate less than 2.0 mmol/L achieved after maximum lactate. Univariable comparisons included age, sex, race, Acute Physiology Score III, Acute Physiology and Chronic Health Evaluation (APACHE) IVa score, Sequential Organ Failure Assessment, surgical ICU admission status, intubation status, hospital region, liver disease, vasopressors, steroids, VitC and THMN orders. Kaplan-Meier curves, logistic regression, propensity score matching, and competing risks modeling were constructed.

RESULTS

Of 146,687 patients from 186 hospitals, 7.7% (n = 11,330) were included. Overall mortality was 25.9% (n = 2,930). Evidence in favor of an association between VitC and/or THMN administration, and survival was found on log rank test (all p < 0.001). After controlling for confounding factors, VitC (adjusted odds ratio [AOR], 0.69 [0.50–0.95]) and THMN (AOR, 0.71 [0.55–0.93]) were independently associated with survival and THMN was associated with lactate clearance (AOR, 1.50 [1.22–1.96]). On competing risk model VitC (AOR, 0.675 [0.463–0.983]), THMN (AOR, 0.744 [0.569–0.974]), and VitC+THMN (AOR, 0.335 [0.13–0.865]) were associated with survival but not lactate clearance. For subgroup analysis of patients on vasopressors, VitC+THMN were associated with lactate clearance (AOR, 1.85 [1.05–3.24]) and survival (AOR, 0.223 [0.0678–0.735]).

CONCLUSION

VitC+THMN is associated with increased survival in septic ICU patients. Randomized, multicenter trials are needed to better understand their effects on outcomes.

LEVEL OF EVIDENCE

Therapeutic Study, Level IV.
Preparedness and vulnerability of African countries against introductions of 2019-nCoV
Authors: Gilbert Marius , Pullano Giulia , Pinotti Francesco , Valdano Eugenio , Poletto Chiara , Boëlle Pierre-Yves , D’Ortenzio Eric , Yazdanpanah Yazdan , Eholie Serge Paul , Altmann Mathias , Gutierrez Bernardo , Kraemer Moritz U.G. , Colizza Vittoria
Published: February 2020

Background

The novel coronavirus (2019-nCoV) epidemic has spread to 23 countries from China. Local cycles of transmission already occurred in 7 countries following case importation. No African country has reported cases yet. The management and control of 2019-nCoV introductions heavily relies on country’s health capacity. Here we evaluate the preparedness and vulnerability of African countries against their risk of importation of 2019-nCoV.

Methods

We used data on air travel volumes departing from airports in the infected provinces in China and directed to Africa to estimate the risk of introduction per country. We determined the country’s capacity to detect and respond to cases with two indicators: preparedness, using the WHO International Health Regulation Monitoring and Evaluation Framework; and vulnerability, with the Infectious Disease Vulnerability Index. Countries were clustered according to the Chinese regions contributing the most to their risk.

Findings

Countries at the highest importation risk (Egypt, Algeria, Republic of South Africa) have moderate to high capacity to respond to outbreaks. Countries at moderate risk (Nigeria, Ethiopia, Sudan, Angola, Tanzania, Ghana, Kenya) have variable capacity and high vulnerability. Three clusters of countries are identified that share the same exposure to the risk originating from the provinces of Guangdong, Fujian, and Beijing, respectively.

Interpretation

Several countries in Africa are stepping up their preparedness to detect and cope with 2019-nCoV importations. Resources and intensified surveillance and capacity capacity should be urgently prioritized towards countries at moderate risk that may be ill-prepared to face the importation and to limit onward transmission.

Funding

This study was partially supported by the ANR project DATAREDUX (ANR-19-CE46-0008-03) to VC; the EU grant MOOD (H2020-874850) to MG, CP, MK, PYB, VC.
Posture adjustment method for large components of aircraft based on hybrid force-position control
Authors: Chu Wenmin , Huang Xiang
Published: February 2020

Purpose

Flexible tooling for adjusting the posture of large components of aircraft (LCA) is composed of several numerical control locators (NCLs). Because of the manufacture and installation errors of NCL, the traditional control method of NCL may cause great interaction force between NCLs and form the internal force of LCA during the process of posture adjustment. Aiming at this problem, the purpose of this paper is to propose a control method for posture adjustment system based on hybrid force-position control (HFPC) to reduce the internal force of posture adjustment.

Design/methodology/approach

First of all, the causes of internal force of posture adjustment were analyzed by using homogeneous transformation matrix and inverse kinematics. Then, axles of NCLs were divided into position control axle and force control axle based on the screw theory, and the dynamic characteristics of each axle were simulated by MATLAB. Finally, a simulated posture adjustment system was built in the laboratory to carry out HFPC experiment and was compared with the other two traditional control methods for posture adjustment.

Findings

The experiment results show that HFPC method for redundant actuated parallel mechanism (RAPM) can significantly reduce the interaction force between NCLs.

Originality/value

In this paper, HFPC is applied to the control of the posture adjustment system, which reduces the internal force of LCA and improves the assembly quality of aircraft parts.
General practitioners' training and their attitudes towards young people who self‐harm: A cross‐sectional survey
Authors: Moriarty Amy , Nearchou Finiki , Byrne Michael , Cullen Walter , Hennessy Eilis
Published: February 2020

Aim

Self‐harm is common among adolescents and young adults and carries increased risk of suicide and other negative outcomes, yet only a small proportion will seek professional help. General practitioners (GPs) are a potentially valuable source of help as most young people visit their GP regularly for other reasons. The primary aim of this research was to explore GPs' empathy and attitudes towards young people who self‐harm and how these are related to GP specialist training.

Method

GPs completed questionnaires regarding their training, levels of empathy, perceived knowledge and attitudes towards young people who self‐harm. The cross‐sectional design included a random sample of 178 GPs and 47 GPs‐in‐training in the Republic of Ireland. Bootstrapped mediation analysis using structural equation modelling (SEM) was applied to explore the pattern of relationships among GP‐training, empathy, perceived knowledge of self‐harm and attitudes towards youth who self‐harm.

Results

The SEM results revealed that the model had a very good fit to the data. Empathy was the strongest predictor of attitudes towards self‐harm even if GPs had received youth mental health training and fully mediated the effect of youth mental health training on perceived knowledge of self‐harm. Specialized training in self‐harm was a stronger predictor of perceived knowledge than empathy but had no association with negative attitudes.

Conclusions

The findings emphasize positive outcomes associated with GP training and highlight potential differences in the effects associated with specific vs general training in youth mental health. These differences may be used to inform the design and implementation of continuing professional development.
Co‐culture of human fibroblasts, smooth muscle and endothelial cells promotes osteopontin induction in hypoxia
Authors: Sadaghianloo Nirvana , Contenti Julie , Dufies Maeva , Parola Julien , Rouleau Matthieu , Lee Shinrong , Peyron Jean‐François , Fabbri Lucilla , Hassen‐Khodja Réda , Pouysségur Jacques , Bost Frédéric , Jean‐Baptiste Elixène , Dardik Alan , Mazure Nathalie M.
Published: February 2020

Arteriovenous fistulas (AVFs) are the preferred vascular access for haemodialysis of patients suffering from end‐stage renal disease, a worldwide public health problem. However, they are prone to a high rate of failure due to neointimal hyperplasia and stenosis. This study aimed to determine if osteopontin (OPN) was induced in hypoxia and if OPN could be responsible for driving AVF failure. Identification of new factors that participate in remodelling of AVFs is a challenge. Three cell lines representing the cells of the three layers of the walls of arteries and veins, fibroblasts, smooth muscle cells and endothelial cells, were tested in mono‐ and co‐culture in vitro for OPN expression and secretion in normoxia compared to hypoxia after silencing the hypoxia‐inducible factors (HIF‐1α, HIF‐2α and HIF‐1/2α) with siRNA or after treatment with an inhibitor of NF‐kB. None of the cells in mono‐culture showed OPN induction in hypoxia, whereas cells in co‐culture secreted OPN in hypoxia. The changes in oxygenation that occur during AVF maturation up‐regulate secretion of OPN through cell‐cell interactions between the different cell layers that form AVF, and in turn, these promote endothelial cell proliferation and could participate in neointimal hyperplasia.
Generalists versus specialists in fluctuating environments: a bet‐hedging perspective
Authors: Haaland Thomas Ray , Wright Jonathan , Ratikainen Irja Ida
Published: February 2020

Bet‐hedging evolves in fluctuating environments because long‐term genotype success is determined by geometric (rather than arithmetic) mean fitness across generations. Diversifying bet‐hedging produces different specialist offspring, whereas conservative bet‐hedging produces similar generalist offspring. However, many fields, such as behavioral ecology and thermal physiology, typically consider specialist versus generalist strategies only in terms of maximizing arithmetic mean fitness benefits to individuals. Here we model how environmental variability affects optimal amounts of phenotypic variation within and among individuals to maximise genotype fitness, and we disentangle the effects of individual‐level optimization and genotype‐level bet‐hedging by comparing long‐term arithmetic versus geometric mean fitness. For traits with additive fitness effects within lifetimes (e.g. foraging‐related traits), genotypes of similar generalists or diversified specialists perform equally well. However, if fitness effects are multiplicative within lifetimes (e.g. sequential survival probabilities), generalist individuals are always favored. In this case, geometric mean fitness optimization requires even more within‐individual phenotypic variation than does arithmetic mean fitness, causing individuals to be more generalist than required to simply maximize their own expected fitness. In contrast to previous results in the bet‐hedging literature, this generalist conservative bet‐hedging effect is always favored over diversifying bet‐hedging. These results link the evolution of behavioral and ecological specialization with earlier models of bet‐hedging, and we apply our framework to a range of natural phenomena from habitat choice to host specificity in parasites.
Research on Improved Simplified SCWR Assembly and Core Design
Authors: Lei Yao , Bangyang Xia , Di Lu , Lianjie Wang
Published: February 2020

A new type of simplified assembly without “water rod” or solid moderator is identified to simplify China Supercritical Water-cooled Reactor with the rated electric power of 1000 MWel (CSR1000) core structure. A study on the properties of this new assembly has been carried out. Under the condition of heat full power, maximum cladding surface temperature (MCST) is 658 °C, very close to safety criterion 650 °C, and maximum linear heat generation rate (MLHGR) is 40.0 kW/m, slightly higher than safety criterion 39 kW/m. Considering rod stuck criterion, the maximum keff is 0.9833, lower than safety criterion 0.99. The discharge burn-up reduced to 21368 MWd/t, a sharp decreasing of 31.1%. This simplified assembly provides a new idea for solving the problem of complex structure of supercritical water-cooled reactor (SCWR).
Hidden figures
The Uncounted
Alex Cobham
Polity, 2020. 240 pp.
Authors: O'Hare William P.
Published: February 2020

Missing population data hinder good accounting and fair resource distribution
Death dollhouses and the birth of forensics
18 Tiny Deaths
Bruce Goldfarb
Sourcebooks, 2020. 368 pp.
Authors: Adam Alison
Published: February 2020

A wealthy patron's vision and macabre models helped forge the field of forensic medicine
Discovering the limits of ecological resilience
Authors: Bridle Jon , van Rensburg Alexandra
Published: February 2020

Bumble bee declines reveal species pushed to the edge of their environmental tolerances