bluuebunny/crossref_metadata_2025 huggingface dataset:
The conjugate profile of the circular teeth of a spur gear. Part II: Problem solution
Authors: Alaci S , Ciornei F-C , Doroftei I
Published: December 2020

The paper aims finding the conjugate profile of a circular profile tooth from a gear mechanism with fixed parallel axes and constant transmission ratio. There are presented three manners of attaining the goal. The first two methods are based on the general methodology of gear wheel toothing by envelope machining presented in the first part of the work, considering elementary mechanisms with fixed axes and then a planetary one. The last method is based on applying the Reuleaux’s fundamental law of gearing and has the advantage of obtaining both the conjugate profile of the gear with circular profile and the line of action which is useful in the study of gearing phenomena.
About some problems regarding IKP-DKP of a 9R planar parallel mechanism
Authors: Buium F , Leohchi D , Alaci S
Published: December 2020

The paper presents some problems which might occur at different stages of the 9R(3RRR) planar mechanisms study (workspace characterizing, forward and direct kinematics, singularities analysis). At each of this stage, it has been identified certain problem which can occur and that need more attention and effort to be solved. In the paper classical methods, and formulas, known from technical literature, have been used, but occurred situations was depicted detailed and illustrated by graphical representations.
Modeling and analysis of some planar deployable mechanisms. Part 2: curvilinear bar mechanisms
Authors: Doroftei I A , Bujoreanu C , Doroftei I
Published: December 2020

Research in deployable structures increased in the last decade, due to the need of building structures that can change their shape or functionality in response to varying of different aspects: climatic conditions, environment, functional requirements or emergency situations. Depending on how the transformation is doing, transformable structures can be deployable or demountable, as a kit-parts system. These structures can be classified in four main groups: structures based on spatial articulated bar mechanisms; foldable plate structures; tensegrity structures; and membrane structures. In this paper, some geometric design aspects of curvilinear bar mechanisms are discussed and a curvilinear structure mechanism is proposed. More results on the geometric design, dimensional synthesis and simulation of this scissor structural mechanism will be presented in future work.
A study of biomechanical model of seated human body exposed to vertical vibrations
Authors: Oncescu A T , Tarnita D , Bolcu D , Malciu R
Published: December 2020

This paper presents a human biomechanical model with 4 degrees of freedom of a human body in a car seat with backrest exposed to vertical vibrations. The proposed model has been analysed for five various values of radian frequency as numerical input data, and the results were compared with the results obtained for similar models in the published literature. In the biodynamic analyses the model was simplified to linear system to reduce the complexity of analytical and numerical simulations.
Design and virtual model of an exoskeleton for lower limb rehabilitation
Authors: Petcu A , Tarnita D , Tarnita D N
Published: December 2020

In this paper the design and the virtual model of an exoskeleton for human lower limb rehabilitation is developed. The proposed exoskeleton is anthropomorphic, low cost and easy to adapt on the human subject. The design aspect concerns the exoskeleton mechatronic structure achieved in Solid Works virtual environment. In order to realize the multibody model, the virtual spatial model of a human mannequin developed in SolidWorks was transferred to the ADAMS database. The movement laws experimentally collected are introduced in each of the 6 rotational joints of the both lower limbs. Simulation of the mannequin walking is performed.
The influence of track characteristics on the stresses introduced in operation in the frame of the electric locomotive class 43, EC 3400 kW
Authors: Alexandrov M , Goanta V , Apostol D , Blanari I
Published: December 2020

In order to carry out maintenance in accordance with the state of the system, the locomotives in operation should be equipped with a system to monitor the main parameters and characteristics of safe operation and minimum risk. This work presents the method of determining the strains and influencing the configuration of the track on specific strains in the case of operation of the electric locomotive class 43, 3400 kW (4620 hp). Two tensometric rosettes with three strain gauges each, from which signals were taken when the electric locomotive operated in operation on a set route, with a trainset. The area in which the transducers were installed was determined by a previous analysis of the locomotive beat. The signals taken from the tensometric transducers were processed by obtaining the main stresses from the assembly points of the brands. The results obtained, i.e. the main stresses were correlated with the geometric configuration of the rail.
Influence of geometric elements on the pressure distribution and the state of tension at non-Hertzian wheel-rail contact
Authors: Blanari I , Goanţă V , Alexandrov M
Published: December 2020

In view of the trends of increased traffic speeds, increase axle load, but also the reduction of the losses of material from the wheel and rail due to wear phenomena, the appearance of undulating wear, fractures of the wheel and rail, it is necessary to know the pressure distribution and the state of tension at wheel-rail contact. This can be obtained either by the finite element method (FEM). Using an elastic body modelling, a very rapid FEA model was obtained for solving the pressure distribution at concentrated wheel-rail contact, for real surfaces, modelling absolutely necessary for any study requiring analysis of the state of tension at such a request, for different situations of this interaction, modifying only the input data: geometric model of wheel and rail, longitudinal elasticity modulus, transverse contraction coefficient, load on wheel, etc.
Some aspects regarding the influence of humidity on the tensile characteristics of GFRP composite material
Authors: Morăraş C , Barsanescu P D , Tugui C A
Published: December 2020

Composite materials have experienced great development in recent years, replacing traditional materials. Designed as metastructures, their properties recommend them in different fields, from sports materials to those in aeronautic and energy industries. In combinations of metallic layers or composites based on carbon/glass fibers, the properties of these materials allowed both the miniaturization of devices and the construction of large lightweight components. The paper aims to present the results of the tensile evaluation of the glass fiber reinforced plastics (GFRP), used in the construction of wind turbine blades. The blades are the most critical components of the wind turbines, being exposed to the damage and the defects that appear during operation can lead to the loss of the integrity of the blade structure. In order to increase the lifetime and to study the defects during operation, tensile tests were performed to determine the mechanical properties on a dry specimen, reinforced at [0 ° / 90 °], and the results obtained were compared with two specimens subjected to immersion in water for 14 and 21 days, two other specimens were immersed in seawater (Black Sea) for 14 and 21 days and one specimen was immersed in liquid nitrogen for 4 days.
Evaluation of mechanical properties of glass fibers chopped strands mat composite subjected to UV degradation
Authors: Stanciu M D , Teodorescu H D , Trandafir M , Guţăş V , Savin A
Published: December 2020

The paper focuses on the evaluation of physical and mechanical features of ageing glass fibers chopped strands reinforced polymeric composite, denoted MAT300. First, the samples were analyzed with chroma meter in order to determine the coefficients of color change. Then, the control samples were subjected to three points bending since the other samples were exposed to ultraviolet radiation UV-A radiation for 216 hours. After ageing, the color parameters were measured and the bending test was performed in the laboratory of the Department of Mechanical Engineering at the Transylvania University of Braşov, on the LS100 Lloyd's Instruments type test machine. Results showed the characteristic curves of the fibers glass chopped strands MAT samples, the values of the modulus of longitudinal elasticity, the strain and the breaking stress. Also, the color parameters (lightness, greenness and yellowness scale) were measured, both before and after test, in the rupture zone, considering that the sample break is accompanied by the delamination of the fiber and matrix layers.
Automatic detection of fibers orientation on composite laminates using convolutional neural networks
Authors: Şerban Alexandru , Barsanescu Paul-Doru
Published: December 2020

The mechanical behaviour and failure of the composite materials are highly influenced by the fibre’s orientation. It is important to decide which type of layers and orientations to use for the layup sequence such that the composite laminate is as light and/or cheap as possible while being capable to carry the load for which it is designed. During the production process it is critical to cut and lay the composite woven according to the optimal layup sequence resulting from the optimization process. Therefore, it is important to develop an automatic system which is capable to accurately detect the fibres orientation from a material picture. In our previous work we proposed such a system based on image processing and computational geometry. The main disadvantage of this system is that it has a lot of parameters which need to be manually tuned for each material. In this paper we propose a simple system which doesn’t need any parameter tuning. It is based on convolutional neural networks and we demonstrate with a lot of examples that it is very accurate, stable and insensitive to image variations. The method was tested on diverse composite laminates and woven with different chromatic and morphological properties.
Effects of the hydrogen addition on combustion in automotive diesel engine
Authors: Ene A M , Pana C , Negurescu N , Cernat A , Fuiorescu D , Nutu C
Published: December 2020

Today, fossil fuel replacement and pollutant emissions reduction can be assured by hydrogen use at the automotive diesel engine, obtaining the engine energetic performance improving. The hydrogen has good combustion proprieties. The paper presents some experimental investigations results carried out at an automotive K9K engine diesel at 2000 rev/min speed and 70% load. They showed that hydrogen might be suitable partial substitute of diesel fuel. The hydrogen use assures the thermal efficiency increase due to combustion improvement through homogeneous air-hydrogen mixture rise. The experimental investigations results show that specific energetic consumption decreases with ~8%, the thermal efficiency increases from 31.9% to 34% due to combustion improvement at the hydrogen content increase. In the same time, due to combustion improvement HC and smoke emissions level decreases with 15% respectively 20%. NOx emissions level decreases with 11% comparative to diesel engine at for a 12% percent of substitute ratio of diesel fuel by hydrogen. At the higher percents of substitute ratio of diesel fuel by hydrogen the NOx emissions level increases due to temperature rise. A great advantage is the CO2 emission level decrease with 12% at the increase of percent of substitute ratio of diesel fuel by hydrogen.
Improving brake efficiency by optimizing the design of a car brake caliper
Authors: Gaidur M , Pascal I , Ciobotar C C , Rakosi E , Talif S , Manolache Gh. , Nazare M
Published: December 2020

The continuous advancement in the field of automotive engineering supports the development of new working techniques regarding the definition of new machine parts. In this study, the topological optimization of a tangentially loaded brake caliper is treated. For the first part of the study, the distribution of forces inside the caliper is explained. In the next stage, the computation stage, the working method approached for topological optimization is described. The results and conclusions are commented in the last part of this paper.
Theoretical and experimental possibilities to set up some sensors systems involved in active safety process
Authors: Ispas N , Năstăsoiu M
Published: December 2020

The safety systems present in the construction of modern motor vehicles fully benefit from all development research efforts in the field of autonomous motor vehicles. In this paper, we have analyzed, theoretically and experimentally, for three distinct types of passenger cars, the following active safety systems: 1. Autonomous Emergency Braking system, designed as an automatic braking process of the vehicle, in response to the detection of a probable collision, to reduce the speed of the vehicle; 2. Forward Collision Warning, implemented as an audiovisual warning that is present on board a motor vehicle, to alert the driver; 3. Dynamic Brake support, which further amplifies the braking force to detect the imminent collision to achieve a higher deceleration than in the situation of a normal speed reduction. As a following were study three states such as: Car-to-Car Rear Stationary as a possible collision in which a vehicle travels forwards towards another stationary vehicle and the front structure of the vehicle strikes the rear structure of the other, Car-to-Car Rear Moving as a probable collision in which a vehicle travels forwards towards another vehicle that is travelling at constant speed and the front structure of the vehicle strikes the rear structure of the other and possible collisions named Car-to-Car Rear Braking in which a vehicle travels forwards towards another vehicle that is travelling at constant speed and then decelerates, and the frontal structure of the vehicle strikes the rear structure of the other. The three situations have been examined, experimentally and theoretic, in order to obtain important information about the configurations of sensor systems that compose safety systems. The work allowed to obtain configuration information, experimentally confirmed, with an impact on the improvement of future autonomous vehicles system.
Simulation possibilities of the internal combustion engine management elements using Lotus Engine Simulation software
Authors: Magdas V B , Mastan D C , Burnete N
Published: December 2020

Nowadays the international regulation regarding the exhaust emission and fuel consumption are going in a progressive restricting direction. Authorities force the researchers toward an optimization of new produced engines by lowering the fuel consumption, the harmful exhaust gases and increasing the overall engine efficiency. By lowering the overall quantity of harmful produced gasses, an optimization of the previously produced engines is a good study direction, where the actual engines are analysed and there may be found different ways to upgrade it to a better, more economical and less harmful way of functioning.

The paper approaches the simulation possibilities of the variable valve timing systems using Lotus Engine Simulation software. More precise, it is showed how to use this tool and introduce, modify and analyse the system mentioned above. After simulating different setups of the engine and continuously varying the functionality parameters, useful result shows different ways for further investigations on the engine optimization.
The finite element analysis of pelvic assembly resulted from a pedestrian’s traffic accident. The analysis of the iliac bone
Authors: Pascal I , Ciobotar C C , Gaidur M , Rakosi E , Manolache Gh , Talif S
Published: December 2020

The purpose of this study is to make a series of finite element analyses of the iliac bone of a pedestrian involved in a car crash. The analyses are of a static type. The conditions for the analyses were chosen as to reflect the reality of the situation. The forces which acted on the iliac bone have been experimentally determined. In this study, the authors want to highlight the benefit of the finite element analysis in the road accidentology field.
Modeling and simulating the activities in an automobile repair shop using ARENA software – part 1
Authors: Radulescu I , Tociu A C , Radulescu A V
Published: December 2020

The automobile repair shop market is a highly competitive domain, also filled with opportunities; any competitive advantage can have a significant impact on the chances of success of a firm in this area of activity. The research contains two parts about modeling and simulating the activities in an automobile repair shop, by using ARENA software. Main steps are: simulating the firm's activities by using ARENA simulations software, analyzing the results, continuously seeking and implementing solutions to optimize the experimental model for an efficient use of the available resources. The analyzed automobile repair shop is performing the following services: concierge, diagnosis, mechanical repairs, bodywork and painting, maintenance and periodic technical inspections. Its activities will be simulated for a number of 289 vehicles in a 9600 minutes time interval, representing 20 working days of 8 h/day each, equal to an average working month. The statistical data are collected and studied; it can be observed that there are resources with a low degree of usage, yet with a high number of interventions performed, also others discrepancies in using human resources and equipment. The main results to be obtained are focused in the
The study of cyclic variability at a n-butanol spark ignition engine fueled
Authors: Sandu Cr , Pana C , Negurescu N , Cernat Al , Fuiorescu D , Georgescu R , Nutu C
Published: December 2020

Alcohols such as ethanol, methanol and butanol have gained more attraction in recent years in the use of alternative fuels at the internal combustion engines (ICE) because of their good combustion properties. The use of the butanol-gasoline blends can lead to a decrease in greenhouse gases (CO2) and pollutants such as unburnt hydrocarbons (HC), carbon monoxide (CO) but may increase nitrogen oxides (NOx). An experimental study carried out on a spark ignition engine fueled with a n-butanol-gasoline blend (10% vol. butanol - 90% vol. gasoline) at an engine load χ=55%, speed of n=2500 rpm and different air excess ratios (λ). The objective of this paper is to determine the effects of n-butanol on combustion, specifically on the cyclic variability. So, the COV values for maximum pressure, indicated mean effective pressure and angles of mass fraction burned -10%, 50% and 90%- are presented The engine fueling with butanol-gasoline blend engine leads to the decrease of the cyclic variability and the COV values don’t exceed the recommended value. A great advantage of n-butanol use is the increase of the thermal efficiency due to the stable engine operation and at lean mixtures.
Impact of weather extremes on fresh air ventilation systems
Authors: Adîncu D A , Popescu A , Atanasiu M
Published: December 2020

In the last decades, climate changes start to have a significant impact on society and environment. Extreme temperatures affect more often the functioning of fresh air ventilation systems, as they are designed according to specific standards and norms, without considering the extreme weather events. The main object of this study is to analyze the extreme weather events registered in six major cities from Romania, based on daily observation data for outdoor air temperature variations (minimum and maximum). The analysis covers the outdoor air temperature data recorded by the local weather stations from these cities over a period of 9 years, between 2011 and 2019.
Analysis of a dual-purpose refrigerating and heat pump system
Authors: Dima D , Ionita C , Vasilescu E E , Gheorghian A T , Dobrovicescu A
Published: December 2020

The study is looking for the optimum configuration of a system that requires refrigeration and heating. An ammonia refrigerator separated from a R152a heat pump are first considered. Water is the hot carrying fluid. Based on the exergy analysis, that points out the location and magnitude of each system operational malfunction, an optimization strategy is considered. Following the optimization procedure the two initial separated systems are coupled by using the condenser of the refrigerating unit to preheat water. Due to the exergy destruction in the water preheating condenser, ammonia is replaced by CO2. The transcritical CO2 heater diminish the exergy destruction with the heat transfer across a finite temperature difference. Solutions for further improving the efficiency of the dual-purpose system focus on the decrease in the throttling valve destruction in the CO2 refrigerating unit.
NZEB design principles for affordable single-family housing accounting for regional climatic conditions
Authors: Dumitraşcu A I , Corduban C G , Hapurne T M , Bliuc I
Published: December 2020

The architecture should be specific to a certain place and a certain culture, not only from the standpoint of formal integration in the existing building stock, but also from the perspective of adapting to the regional climatic conditions. Thus, the importance of a “regional” applied concept in the global context regarding NZEB (Nearly Zero Energy Building) design must be emphasized. This paper presents a methodology for evaluation of a NZEB single-family house, taking into account specific climatic characteristics and use of passive design principles for cost optimization. Based on detailed climate data, the most efficient passive measures for the studied region were analyzed. The single-family housing project was evaluated through a BIM (Building Information Modeling) methodology and the result was optimized and compared with National and European standards for NZEB.
Compression ignition engine - sources of pollution
Authors: Istrate A , Bică M , Simion M
Published: December 2020

The high reliability and efficiency of the compression ignition engine as well as its low operating costs turned this engine into the preferred propulsion system for both cars and heavy vehicles. At the same time, the harmfulness of his pollutant emissions gave him the unpleasing status of First Culprit for the many health problems of the population in the metropolis. Currently, the compression ignition engine is mainly responsible for the release of five types of pollutant emissions into the atmosphere: carbon monoxide-CO, hydrocarbons-HC, mechanical particles-PM, sulphur dioxide-SO2 and nitrogen oxides-NOx. Thus, while emissions of carbon monoxide-CO and hydrocarbon-HC are low, due to the fact that this engine usually works with lean mixtures, high emissions of nitrogen oxides-NOx and mechanical particles-PM raise serious pollution problems worldwide.
Air-to-water heat pumps: the impact of climate, compressor technology, water output temperature and sizing on the seasonal coefficient of performance for heating
Authors: Mouzeviris G A , Papakostas K T
Published: December 2020

Air-to-water heat pumps (AWHPs) are devices that will broadly replace heating systems based on fossil fuels. The performance of AWHPs in heating operation is strongly influenced by various parameters such as the climate of the location, the hot water output temperature to the heat emitters, the oversizing or downsizing of the HP with respect to the thermal load of the building, the control system, and the heat pump’s compressor technology (fixed-capacity and inverter-driven HPs). The aim of this work is to study the impact of those parameters on the seasonal efficiency for heating of AWHPs in buildings at representative cities of the four Greek climatic zones. The active mode seasonal coefficient of performance (SCOPon) was estimated in various case studies, with the method proposed in European standard EN 14825, by using climatic data of the four locations. The results show the positive effect of lowering the water supply temperature to the heating system and of using inverter technology and control system with compensation on AWHPs efficiency. Additionally, it is demonstrated that the optimal performance of inverter-driven HPs appears when they are sized at the design outdoor air temperature, while in the case of the fixed-capacity HPs when they are down-sized.
CFD analysis of a round shaped air cushion vehicle with inclined skirt segments
Authors: Pavăl M S , Popescu A , Zahariea D
Published: December 2020

This article presents various two-dimensional CFD analyses specific to the area of the flexible skirt segments for a round-shaped air cushion vehicle. This study aims to analyse the flexible skirt segments and the influence of their inclination angle on the lift force values. The simulations, as well as the geometries of the flow domain, were carried out with ANSYS Fluent software, in which three parameters varied: tilt angle, segment height and air clearance height. The choice of segments height was based on a previous study by the authors and the values for air clearance height imposed in the present study were 10, 20, 30, 40 and 50 mm. Regarding the values of the inclination angles, three values were imposed: 45°, 60° and 75°. Using ANSYS CFD-Post application, the resulting pressure / velocity contours and streamlines are interpreted and with Curve Fitting Toolbox application within the MATLAB program, the curves describing lift forces obtained from the simulation are approximated.
Maximum energy efficiency on photovoltaic solar panels by using an innovative solar tracker
Authors: Sgârciu I A , Cernian A S , Anghel A M , Sgârciu V
Published: December 2020

The solutions currently used for the acquisition of solar energy are based on fixed mechanical structures, in which the photovoltaic panels are either ground-mounted or building-integrated, positioned on suitable rooftops. Both solutions involve the partial take-over of solar energy, thus a reduced energy efficiency of the photovoltaic installation. The solution proposed by the authors of the paper has an innovative mechanical construction and a mixed mode of operation, which combines the secular way with that of the tracking. The operation of the solar tracker presented in the paper is based on the programming in LabVIEW, with the use of a general module for the acquisition/generation of analogue and digital signals. The design developed by the authors has a simple mechanical construction, and the positioning considers the clock of the PC, so that the initial positioning (at start-up) is done in a simplified manner, regardless of the geographical placement of the tracker. The authors performed experiments in the laboratory and in the field, the results being consistent with the theoretical assumptions.
Exergy and performance analyses of impact subcooling for vapor compression refrigeration system utilizing eco-friendly refrigerants
Authors: Tarish A L , Al Douri J , Apostol V , Pop H L , Ionita C
Published: December 2020

In the present paper, performance and exergy analysis for a vapor compression refrigeration system (VCRS) operating with eco-friendly refrigerants such as R1234ze and R1234fyare tested under different operation conditions to change the recently worked refrigerants R-134a. An analysis through performance and exergy is performed to guide the thermodynamic improvement for the VCRS. Additionally, a comprehensive study is conducted to examine the effects of subcooling temperature on performance and exergy destruction in all components of the VCRS. The exergy destruction of the compressors, condenser, evaporator and expansion device were calculated to obtain the exergy efficiencies. For simulation and analysis the VCRS, Engineering Equation Solver (EES) software program was utilized to obtain the thermodynamics refrigerant properties in which the system operates with the highest eco-friendly, energy and exergy performance is developed the VCRS to determine the most suitable alternative refrigerant to replace the R134a. The results indicate that the refrigerant R1234yf showed the greatest COP enhancement 16.7% due to subcooling, followed by R1234ze 14% and R134a 12.8% under the same operating conditions.
Hyperactive MEK1 Signaling in Cortical GABAergic Neurons Promotes Embryonic Parvalbumin Neuron Loss and Defects in Behavioral Inhibition
Authors: Holter Michael C , Hewitt Lauren T , Nishimura Kenji J , Knowles Sara J , Bjorklund George R , Shah Shiv , Fry Noah R , Rees Katherina P , Gupta Tanya A , Daniels Carter W , Li Guohui , Marsh Steven , Treiman David Michael , Olive Michael Foster , Anderson Trent R , Sanabria Federico , Snider William D , Newbern Jason M
Published: December 2020

Many developmental syndromes have been linked to genetic mutations that cause abnormal ERK/MAPK activity; however, the neuropathological effects of hyperactive signaling are not fully understood. Here, we examined whether hyperactivation of MEK1 modifies the development of GABAergic cortical interneurons (CINs), a heterogeneous population of inhibitory neurons necessary for cortical function. We show that GABAergic-neuron specific MEK1 hyperactivation in vivo leads to increased cleaved caspase-3 labeling in a subpopulation of immature neurons in the embryonic subpallial mantle zone. Adult mutants displayed a significant loss of parvalbumin (PV), but not somatostatin, expressing CINs and a reduction in perisomatic inhibitory synapses on excitatory neurons. Surviving mutant PV-CINs maintained a typical fast-spiking phenotype but showed signs of decreased intrinsic excitability that coincided with an increased risk of seizure-like phenotypes. In contrast to other mouse models of PV-CIN loss, we discovered a robust increase in the accumulation of perineuronal nets, an extracellular structure thought to restrict plasticity. Indeed, we found that mutants exhibited a significant impairment in the acquisition of behavioral response inhibition capacity. Overall, our data suggest PV-CIN development is particularly sensitive to hyperactive MEK1 signaling, which may underlie certain neurological deficits frequently observed in ERK/MAPK-linked syndromes.
Perceived risk, environmental attitude and fertilizer application by vegetable farmers in China
Authors: Xiang Zhaoyang , Tian Qingsong , Li Qianling
Published: December 2020

In this study, we investigated the impact of three different perceived risk and environmental attitude on the fertilizer reduction behavior in vegetable production and the interplay between perceived risk and environmental attitude. We found that perceived economic risk can exert a significant and negative effect on farmers’ fertilizer reduction behavior (−0.39) and perceived social and psychological risks has a relatively weak negative impact with coefficients of −0.25 and −0.23, respectively. A more friendly environmental attitude can significantly and positively affect farmers’ fertilizer reduction behavior. Furthermore, environmental attitude has a moderating effect on the association between perceived risk and farmer’s fertilizer reduction behavior, but just significant for economic and social risk. In other words, a better environmental attitude could reduce the negative effect of perceived risk. This study promoted our new understanding of the risk perception’s impact on farmers’ behavior.
Mapping VIS-terahertz (≤17 THz) surface plasmons sustained on native and chemically functionalized percolated gold thin films using EELS
Authors: Abellan Patricia , El-Khoury Patrick Z , Ramasse Quentin M
Published: December 2020

Heterogeneous assemblies of molecules (Rhodamine B) adsorbed onto a nano-corrugated metallic surface (a percolated Au network) are investigated using electron energy loss spectroscopy in the scanning transmission electron microscope (STEM-EELS). Our first measurements target the native metallic substrate, which consists of a commercial Au thin film atop an ultrathin carbon membrane. The Au film displays a percolated morphology with nanostructures of estimated thickness ≤10 nm approximately. We observe a rich plasmonic response from the metallic substrate; one which varies nanometrically and spans the VIS-terahertz region. Multiple localized plasmons are detected at individual nanometric integrated areas, while an analysis of their spatial distribution reveals that for each integrated energy range (50 meV integration window) resonances are simultaneously supported at different locations within the film. We record subsequent EEL spectrum images of the hybrid molecular–metallic construct after deposition of Rhodamine B molecules onto the substrate, where plasmons, molecular vibrations and electronic excitations might all be simultaneously detected. A comparison of average signals for both systems is performed and spectral variations within the three spectral regions where molecular signatures may be observed are discussed. Our measurements and their analysis, if applied to the same location before and after molecular deposition, may be used to rationalize optical microscopic and spectroscopic measurements that take advantage of the interplay between molecules and plasmons.
Development of a secondary electron energy analyzer for a transmission electron microscope
Authors: Magara Hideyuki , Tomita Takeshi , Kondo Yukihito , Sato Takafumi , Akase Zentaro , Shindo Daisuke
Published: December 2020

A secondary electron (SE) energy analyzer was developed for a transmission electron microscope. The analyzer comprises a microchannel plate (MCP) for detecting electrons, a coil for collecting SEs emitted from the specimen, a tube for reducing the number of backscattered electrons incident on the MCP, and a retarding mesh for selecting the energy of SEs incident on the MCP. The detection of the SEs associated with charging phenomena around a charged specimen was attempted by performing electron holography and SE spectroscopy using the energy analyzer. The results suggest that it is possible to obtain the energy spectra of SEs using the analyzer and the charging states of a specimen by electron holography simultaneously.
Pre-processing, group accretion, and the orbital trajectories of associated subhaloes
Authors: Bakels Lucie , Ludlow Aaron D , Power Chris
Published: December 2020

We use a high-resolution cosmological dark matter-only simulation to study the orbital trajectories of haloes and subhaloes in the environs of isolated hosts. We carefully tally all apsis points and use them to distinguish haloes that are infalling for the first time from those that occupy more evolved orbits. We find that roughly 21 per cent of resolved subhaloes within a host’s virial radius are currently on first infall, and have not yet reached their first orbital pericentre; roughly 44 per cent are still approaching their first apocentre after infall. For the range of host masses studied, roughly half of all accreted systems were pre-processed prior to infall, and about 20 per cent were accreted in groups. We confirm that the entire population of accreted subhaloes – often referred to as ‘associated’ subhaloes – extends far beyond the virial radii of their hosts, with roughly half currently residing at distances that exceed ≈1.2 × r200. Many of these backsplash haloes have gained orbital energy since infall, and occupy extreme orbits that carry them well past their initial turnaround radii. Such extreme orbits are created during the initial accretion and dissolution of loosely bound groups, but also through penetrating encounters between subhaloes on subsequent orbits. The same processes may also give rise to unexpectedly abrupt losses of orbital energy. These effects combine, giving rise to a large variation in the ratio of sequent apocentres for accreted systems. We find that, within two virial radii from host centres, the concentrations of first-infall haloes are remarkably similar to those of isolated field haloes, whereas backsplash haloes, as well as systems that were pre-processed, are considerably more concentrated.
The complex architecture of p53 binding sites
Authors: Senitzki Alon , Safieh Jessy , Sharma Vasundhara , Golovenko Dmitrij , Danin-Poleg Yael , Inga Alberto , Haran Tali E
Published: December 2020

Sequence-specific protein-DNA interactions are at the heart of the response of the tumor-suppressor p53 to numerous physiological and stress-related signals. Large variability has been previously reported in p53 binding to and transactivating from p53 response elements (REs) due, at least in part, to changes in direct (base) and indirect (shape) readouts of p53 REs. Here, we dissect p53 REs to decipher the mechanism by which p53 optimizes this highly regulated variable level of interaction with its DNA binding sites. We show that hemi-specific binding is more prevalent in p53 REs than previously envisioned. We reveal that sequences flanking the REs modulate p53 binding and activity and show that these effects extend to 4–5 bp from the REs. Moreover, we show here that the arrangement of p53 half-sites within its REs, relative to transcription direction, has been fine-tuned by selection pressure to optimize and regulate the response levels from p53 REs. This directionality in the REs arrangement is at least partly encoded in the structural properties of the REs. Furthermore, we show here that in the p21-5′ RE the orientation of the half-sites is such that the effect of the flanking sequences is minimized and we discuss its advantages.
An unexpected large continental source of reactive bromine and chlorine with significant impact on wintertime air quality
Authors: Peng Xiang , Wang Weihao , Xia Men , Chen Hui , Ravishankara A R , Li Qinyi , Saiz-Lopez Alfonso , Liu Pengfei , Zhang Fei , Zhang Chenglong , Xue Likun , Wang Xinfeng , George Christian , Wang Jinhe , Mu Yujing , Chen Jianmin , Wang Tao
Published: December 2020

Halogen atoms affect the budget of ozone and the fate of pollutants such as hydrocarbons and mercury. Yet their sources and significances in polluted continental regions are poorly understood. Here we report the observation of unprecedented levels (averaging at 60 parts per trillion) of bromine chloride (BrCl) at a mid-latitude site in North China during winter. Widespread coal burning in rural households and a photo-assisted process were the primary source of BrCl and other bromine gases. BrCl contributed about 55% of both bromine and chlorine atoms. The halogen atoms increased the abundance of ‘conventional’ tropospheric oxidants (OH, HO2 and RO2) by 26%–73%, and enhanced oxidation of hydrocarbon by nearly a factor of two and the net ozone production by 55%. Our study reveals the significant role of reactive halogen in winter atmospheric chemistry and the deterioration of air quality in continental regions where uncontrolled coal combustion is prevalent.
Outcomes of Vascular and Endovascular Interventions Performed During the Coronavirus Disease 2019 (COVID-19) Pandemic
Authors: Benson Ruth A. , Nandhra Sandip
Published: December 2020

Objective:

The aim of the COVER Study is to identify global outcomes and decision making for vascular procedures during the pandemic.

Background Data:

During its initial peak, there were many reports of delays to vital surgery and the release of several guidelines advising later thresholds for vascular surgical intervention for key conditions.

Methods:

An international multi-center observational study of outcomes after open and endovascular interventions.

Results:

In an analysis of 1103 vascular intervention (57 centers in 19 countries), 71.6% were elective or scheduled procedures. Mean age was 67 ± 14 years (75.6% male). Suspected or confirmed COVID-19 infection was documented in 4.0%. Overall, in-hospital mortality was 11.0% [aortic interventions mortality 15.2% (23/151), amputations 12.1% (28/232), carotid interventions 10.7% (11/103), lower limb revascularisations 9.8% (51/521)]. Chronic obstructive pulmonary disease [odds ratio (OR) 2.02, 95% confidence interval (CI) 1.30–3.15] and active lower respiratory tract infection due to any cause (OR 24.94, 95% CI 12.57–241.70) ware associated with mortality, whereas elective or scheduled cases were lower risk (OR 0.4, 95% CI 0.22–0.73 and 0.60, 95% CI 0.45–0.98, respectively. After adjustment, antiplatelet (OR 0.503, 95% CI: 0.273–0.928) and oral anticoagulation (OR 0.411, 95% CI: 0.205–0.824) were linked to reduced risk of in-hospital mortality.

Conclusions:

Mortality after vascular interventions during this period was unexpectedly high. Suspected or confirmed COVID-19 cases were uncommon. Therefore an alternative cause, for example, recommendations for delayed surgery, should be considered. The vascular community must anticipate longer term implications for survival.
Structural insights into the recognition of histone H3Q5 serotonylation by WDR5
Authors: Zhao Jie , Chen Wanbiao , Zhang Yinfeng , Yang Fan , Shen Nan , Zhang Xuan , Mo Xi , Zang Jianye
Published: December 2020

Serotonylation of histone H3Q5 (H3Q5ser) is a recently identified posttranslational modification of histones that apparently acts as a permissive marker for gene activation in synergy with H3K4me3 during neuronal cell differentiation. However, any proteins which specifically recognize H3Q5ser remain unknown. Here, we discovered that WDR5 interacts with the N-terminal tail of histone H3 and functions as a ‘reader’ for H3Q5ser. Crystal structures of WDR5 in complex with H3Q5ser and H3K4me3Q5ser peptides revealed that the serotonyl group is accommodated in a shallow surface pocket of WDR5. Experiments in neuroblastoma cells demonstrate that WDR5 colocalizes with H3Q5ser in the promoter regions of cancer-promoting genes, where it promotes gene transcription to induce cell proliferation. Thus, beyond revealing a previously unknown mechanism through which WDR5 reads H3Q5ser to activate transcription, our study suggests that this WDR5-H3Q5ser mediated epigenetic regulation apparently promotes tumorigenesis.
Probiotic fermented milk with high content of polyphenols: Study of viability and bioaccessibility after simulated digestion
Authors: Pena Fabíola L , Souza Mariana C , Valle Maria Carolina P R , Bezerra Rosangela M N , Rostagno Maurício A , Antunes Adriane E C
Published: December 2020

This research evaluated the functional potential of a fermented milk made with Streptococcus thermophilus, a probiotic (Bifidobacterium animalis subsp. lactis) and pomegranate juice. Ferric‐reducing antioxidant potential, Trolox equivalent antioxidant capacity, scavenging effect on 1,1‐diphenyl‐2‐picrylhydrazyl free radical, oxygen radical absorbance capacity and Folin–Ciocalteu assays were used to estimate antioxidant activity and phenolic content. Probiotic survival, release and absorption of polyphenols were evaluated using in vitro gastrointestinal digestion. The concentration of polyphenols increased during digestion from 608 mg to 1417  gallic acid equivalents (GAE) /L. About 14% of polyphenols were found on the dialysate portion. The beverage presented high viability of probiotics with high survival rate after digestion (above 7 log cfu/mL).
Resource Adjustment Costs, Cost Stickiness, and Value Creation in Mergers and Acquisitions*
Authors: Jang Youngki , Yehuda Nir
Published: December 2020

We examine whether resource adjustment costs, such as installation and disposal costs for fixed assets, or hiring and firing costs for employees, impede value creation in mergers and acquisitions (M&A). We focus on M&A deals because they are major corporate investment decisions. As a proxy for adjustment costs, we use a firm‐level measure of cost stickiness. We predict that acquirers with high adjustment costs have less flexibility in restructuring resources following the acquisition and will find it more costly to merge the target firm's operations. Consistent with this prediction, we find that the acquirer's adjustment costs are negatively associated with abnormal returns around the acquisition announcement. Additionally, adjustment costs are also negatively associated with deal synergies. Relatedly, we find that acquirers with high adjustment costs purchase targets with high adjustment costs. In accordance with this finding, we show that acquirers with high adjustment costs purchase intangible‐intensive targets. Collectively, our results highlight the important implication of adjustment costs in M&A deals for managers and capital market participants.
New developments in corneal endothelial cell replacement
Authors: Spinozzi Daniele , Miron Alina , Bruinsma Marieke , Dapena Isabel , Kocaba Viridiana , Jager Martine J. , Melles Gerrit R. J. , Ni Dhubhghaill Sorcha , Oellerich Silke
Published: December 2020

Corneal transplantation is currently the most effective treatment to restore corneal clarity in patients with endothelial disorders. Endothelial transplantation, either by Descemet membrane endothelial keratoplasty (DMEK) or by Descemet stripping (automated) endothelial keratoplasty (DS(A)EK), is a surgical approach that replaces diseased Descemet membrane and endothelium with tissue from a healthy donor eye. Its application, however, is limited by the availability of healthy donor tissue. To increase the pool of endothelial grafts, research has focused on developing new treatment options as alternatives to conventional corneal transplantation. These treatment options can be considered as either ‘surgery‐based’, that is tissue‐efficient modifications of the current techniques (e.g. Descemet stripping only (DSO)/Descemetorhexis without endothelial keratoplasty (DWEK) and Quarter‐DMEK), or ‘cell‐based’ approaches, which rely on in vitro expansion of human corneal endothelial cells (hCEC) (i.e. cultured corneal endothelial cell sheet transplantation and cell injection). In this review, we will focus on the most recent developments in the field of the ‘cell‐based’ approaches. Starting with the description of aspects involved in the isolation of hCEC from donor tissue, we then describe the different natural and bioengineered carriers currently used in endothelial cell sheet transplantation, and finally, we discuss the current ‘state of the art’ in novel therapeutic approaches such as endothelial cell injection.
Identification of microorganisms directly from blood culture bottles with polymicrobial growth: comparison of FilmArray and direct MALDI‐TOF MS
Authors: Almuhayawi Mohammed S. , Wong Alicia Y. W. , Kynning Max , Lüthje Petra , Ullberg Måns , Özenci Volkan
Published: December 2020

Bloodstream infections (BSIs) are related to high mortality and morbidity. Rapid administration of effective antimicrobial treatment is crucial for patient survival. Recently developed rapid methods to identify pathogens directly from blood culture bottles speed up diagnosis of BSIs. The present study compares the performance of two rapid identification methods, FilmArray and direct MALDI‐TOF MS, on identifying microorganisms directly from positive blood culture bottles with polymicrobial growth. FilmArray and direct MALDI‐TOF MS were performed directly on positive clinical and simulated polymicrobial blood culture bottles. Assay results were compared with standard culture methods. In total, 110 polymicrobial blood culture samples, of which 96 samples contained two microorganisms while 14 samples contained three microorganisms, were studied. FilmArray was able to identify 215/234 (92.0%) of isolates detected by the standard culture method and successfully identified all microorganisms in 88/110 (80.0%) of blood culture bottles. In contrast, direct MALDI‐TOF MS was only able to identify 65/234 (27.8%) of isolates and managed to identify all microoganisms in 2/110 (2.1%) of blood culture bottles. FilmArray is a rapid method for direct identification of polymicrobial blood culture samples that can complement the conventional identification methods. Direct MALDI‐TOF MS has low performance with polymicrobial samples.