bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved design for accelerated consolidation of subgrade when building a highway on a weak base
Authors: Borychev S N , Popov A S , Koloshein D V
Published: March 2021

This article deals with the design of the foundation of the subgrade of a motor road on a weak foundation (peat, sapropel) in difficult climatic and engineering-geological conditions. The features of physical and mechanical properties of soft soils imply the creation of non-typical design solutions using modern technologies and building materials. As a result, the theoretical studies of the processes of accelerated consolidation of weak soils were carried out and a design of the subgrade was proposed based on the use of electro-physical and filtration properties of various aggregates, namely the cathode layer (crushed stone from blast furnace coke or conductive coal), the drainage layer (sand) and the anode layer (crushed stone from dolomite limestone or basalt). The developed structure will allow reducing the consolidation time of a weak base and providing the necessary strength of the base by increasing shear resistance, which will increase the durability and reliability of the road, as well as reduce the technological construction time.
Evaluation of the trailbuilder hydraulic drive thermal preparation
Authors: Konev V V
Published: March 2021

One of the main problems in operation of road-building machines in conditions of low negative ambient temperatures is the hydraulic drive thermal preparation. The hydraulic equipment is located throughout the machine and need a local thermal warming otherwise its cold start results in its intense wear. We propose the warming method that comprises circulation of a prewarmed hydraulic fluid from the hydraulic tank through the piston and rod chambers of hydraulic cylinder without rod motion. This is ensured by installation of a bypass pipe and a valve connecting the hydraulic cylinder piston and rod chambers. To evaluate operability of the hydraulic cylinder warming system we determined the fluid circulation conditions depending on the fluid flow rate and its temperature. To check these conditions, we made calculations for a trailbuilder hydraulic drive with a ripper.
Technology of making asphalt concrete using sand slag
Authors: Kovalev N S , Otarova E N , Gladnev V V , Sadygov E A , Demidov P V , Yaurova I V
Published: March 2021

In the Central Black Earth Region, there are settlements that do not have hard-surfaced access roads, and existing access roads require major repairs. In order to reduce the cost of construction, it is proposed to use asphalt concrete mixtures from slag materials for the construction of road pavements. Slag materials have hydraulic binding properties; the processes of structure formation in them take a long time. The study of the properties of asphalt concrete was carried out depending on the time from the moment of manufacture, after prolonged water saturation and the number of freeze-thaw cycles. The obtained results indicate an increased durability of asphalt concrete road pavements made of slag materials.
Modeling the stress-strain state of crane metal structures
Authors: Lenivtsev A G , Dudanov I V
Published: March 2021

The intensification of construction production imposes very strict requirements on the safety of construction machines. When carrying out lifting and hoisting operations using overhead cranes, production safety is primarily determined by the technical condition of the undercarriage and crane runways, as well as metal constructions. The authors deal with the issues related to modeling and research of the stress-strain state of metal structures of an overhead crane. A model of the crane metal structure is proposed, which includes the main and end box-section crane girders. To study possible geometric movements of the crane, a model of an overhead crane was designed in KOMPAS-3D software environment. The model contains main and end box-section girders. The model allows determining the maximum possible misalignment of the crane and runout of one of the sides. To determine the bending, tensile and compressive stresses in the bridge truss and the deformations of the crane metal structures, depending on the working loads, a 3D model of the bridge crane was created in the ADW Winmachine software environment. With its help, the bending stiffness of the crane bridge was established. These values are necessary to compile a mathematical model of an overhead crane as a control object in the synthesis of an automatic control system.
Mathematical modeling of thermal processes in building enclosures
Authors: Maslyanitsyn A P , Galitskov K S , Fadeev A S
Published: March 2021

In the development of automatic control systems (ACS) for heat supply of buildings, mathematical models of their control objects play a significant role, one of the most important elements of which being the enclosing structures. The existing models of thermal processes indoors either do not take into account the dynamic effect of the enclosing structures, or are complex analytical expressions, the use of which in the engineering practice of the synthesis of ACS for the indoor thermal regime is difficult. The purpose of the study was to create a linear mathematical model of the thermal interaction of the external and internal air environment through the enclosing structures. To achieve this goal, a functional diagram of a heated room as a control object was developed, which describes the mechanism of thermal interaction of its elements. On its basis, design schemes of thermal processes for external and internal enclosing structures were developed. They were used to create systems of equations linking temperatures on the surfaces of layers of external enclosing structures and air temperatures outside and inside the premises. At the same time, the assumption was introduced that the dynamic temperature distribution over the thickness of the enclosing structure is linear. To find the temperatures at the boundaries of the layers, the average temperature value over the thickness of the structure was used. As a result of the study, equations for the dynamics of heat transfer processes were obtained, and a generalized structure of a model of multilayer external enclosing structures of a room as an element of a control object was developed. The resulting model can be used to develop a generalized mathematical model of the thermal regime of both individual rooms and the building as a whole.
Design of prefabricated reinforced concrete structures: comparative analysis of prefabricated reinforced concrete floor slab
Authors: Evstratova A V , Krishtalevich A K , Belov V V , Nikitin S E
Published: March 2021

The article describes application of precast, cast-in-situ and composite structures on construction site. Importance of Analysis of Russian (SP) and European design standards (EuroCodes) is underlined. Historical review of Russian codes for composite reinforced concrete structures is given. Methods of composite structures calculating according to current Russian Codes are given. Ultimate and service limits states are listed for describing structures. Advantages and disadvantages of cast-in-situ, prefabricated and complex technologies are discussed. Comparison of prefabricated, monolithic and complex technologies is given on example of intermediate floor slab. Examples of sections of prefabricated reinforced concrete composite structures are summarized. Composite structures detailing is given on example of real project of Parking building of Okhta-Mall shopping and entertainment center, Saint-Petersburg. Constructive solutions are presented that increase the bearing capacity and resistance to progressive collapse of structures. Manufacturing photos of prefabricated ready-made reinforced concrete slabs as a part of future composite slab are presented. Examples of detail drawings for composite concrete slabs, executed in accordance to Eurocode, are given. Suggestions for improving the existing Code of Practice are given. Reference to similar scientific papers is presented related to composite reinforced concrete elements. Article is developed with financial and technical information support of AFRY Oy Finland.
Transport hubs as experimental ground for new construction materials
Authors: Guzhov S , Korchagin A
Published: March 2021

The research purpose is to clarify the role, significance and problems inherent in transport hubs in the implementation of engineering solutions using new construction materials. The traditional scheme of commutation of passenger traffic between different modes of transport allows building physical models. However, the efficiency of materials in structures and the study of their operational properties are additional tasks for the calculation in new conditions. Historically, many large cities are characterized by a lag in the development of transport infrastructure in comparison with the growth rates of cities. The material and technical supply of construction inevitably faces the problem of the depletion of materials from their operational properties. Massive daily movement of the population to places of job and high operational loads reveal disadvantages primarily in terms of the traditional materials. The way out of this situation is the development of transport interchange hubs, while the use of traditional constructive and technological solutions causes additional difficulties for transport companies and businesses. The presentation of the key elements of the transport infrastructure as a testing ground for testing the properties of new materials such as high-alloy steels, composite materials, superplasticized concretes allows solving the problems of construction engineering in a new way. The constructed transport hubs rarely comply with the loading standards, which is caused by the incorrect approach to their design: the existing construction rules are not comparable with the functional needs of new type facilities. For the assessment, such factors as material consumption, creation of regulatory conditions, quality and safety of materials, reduction in construction time, stability of functioning and others are used. The risks associated with the creation of transport interchange hub (TIH) are noted. The development of transport hubs in a megalopolis can be implemented during simultaneous improvement of the quality of applied construction materials and satisfaction of the commercial interest of investors. In addition to the direct technological effects, there are accompanying operational consequences in various areas of urban life.
Reasonable choice of materials for project management in transport construction
Authors: Solovev V
Published: March 2021

Material and technical supply is traditionally considered as a set of activities united by one project purpose. As a rule, a hierarchical approach to management functions is not applied and the links between management functions are determined by the classical form of the implementation of a construction project. The selection of the best types of material resources and its component that is the costs determined by the properties of the applied materials are becoming a key link in project management in modern Russia. This is an important scientific phenomenon. The research of this phenomenon allows finding the problem points in costing and the solution to the problems of the increase in the efficiency of building materials assembly through them. The relevance of this research is important for those countries where there is strong regulation of the estimated cost. The authors of the paper propose the measures to improve the efficiency of the choice of construction materials due to a more reliable determination of the estimated cost. For this, there are two ways to improve the project bill of materials: through the improvement of the regulatory framework and management of the process of the application of this framework. The quality level of resource and cost norms is a paramount problem in conditions of state regulation. This is intensified by the use of the basic costing method. The lag of norms calculated at the basic cost level can not be compensated for the use of conversion indices due to territorial and industrial classification. The attempts to create in Russia a unified information system for setting costs for construction products have not yet had measurable results. This results in a large percentage of outdated regulations that take into account materials with insufficient usability. The participants of the construction process have to spend large human resources to manage material resources in projects. The process of management in terms of material and technical equipment of construction is on top in terms of importance in the field of project management in transport construction. The quality of the projects being implemented largely depends on the success in the improvement of the regulatory framework.
Numerical analysis on motion of microparticles passing through straight and tortuous fibrous layers
Authors: Otomo Ryoko , Mori Kazuki
Published: March 2021

The behavior of microparticle assemblage moving through the saturated pores in a fibrous layer has been investigated numerically. We adopted a particle model to express the straight and tortuous fibrous layers and calculated the velocities of individual microparticles using the Stokesian dynamics approach assuming the Stokes flow. The simulation results showed that the particles spread as they moved through the layer. This is interpreted as hydrodynamic diffusion caused by the hydrodynamic interaction dominant in the Stokes flow. More pronounced diffusion was observed in the tortuous fibrous layer than in the straight one. It was found that the velocity of each particle deviated more from the ensemble average velocity of the assemblage in the tortuous fibrous layer. It was also observed that the tortuous fibrous layers exhibited greater variation in the size of the pores where particles passed. Our results quantitatively indicated that the tortuous fibrous layer consisted of a wide variety of pore sizes, which affects the velocity of the particles passing through it. Consequently, the difference in each particle velocity causes the hydrodynamic diffusion. It was also revealed that the subtle difference in the fiber shape substantially influences the hydrodynamic behavior of the particles moving inside.
Multiple mode-locked regimes of an Er/Yb double-clad fiber laser based on NPR
Authors: Durán-Sánchez Manuel , Pottiez Olivier , Posada-Ramírez Berenice , Álvarez-Tamayo Ricardo I , Armas-Rivera Iván , Bello-Jiménez Miguel , García-Flores Yasser A , Montiel-Piña E , Ibarra-Escamilla Baldemar
Published: March 2021

In this paper, we experimentally demonstrate generation of diverse structures of robust optical pulses obtained with a ring cavity passively mode-locked fiber laser based on a double-clad erbium-ytterbium doped fiber, and operating at net-anomalous cavity dispersion. A half-wave and a quarter-wave retarder plates allow adjustable saturable absorbing action by the nonlinear polarization rotation technique. Pulsed laser operation in quasi- continuous wave, molecules of solitons, and single-wavelength noise-like pulses (NLPs) regimes is obtained by properly adjusting the wave retarders. In the soliton and NLPs operating regimes, the central laser wavelength lies in the 1540 nm region. The obtained NLPs exhibit narrow peak coherence of ∼231 fs.
A review on the different types of electrode materials for aqueous supercapacitor applications
Authors: Chaudhary Swati , Raja Mohan , Sinha O P
Published: March 2021

The recent advancements in living standards impose massive pressure on existing energy resources such as fossil fuels. Also, the increasing number of inhabitants arises the need to develop eco-friendly and sustainable energy storage systems. In this regard, a large number of researchers have paid increasing attention to the different methods for sustainable energy like the use of solar cells, LEDs, energy-efficient electronic devices, and supercapacitor technology. Since supercapacitors belong to the class of energy storage systems that provides high capacitive performance and charging-discharging stability during long cycles. They also offer higher power density than batteries and higher energy density than capacitors. Since the selection of electrode material and its electrochemical performance is the most determined parameter for supercapacitor performance. The present review focuses on the different types of aqueous electrolyte based electrode material which is differentiated based on energy storage mechanisms for aqueous supercapacitors. Furthermore, the latest nanocomposites reported have been reviewed and differentiated based on their electrochemical performance for aqueous supercapacitor applications. Their future implications have also been discussed.
Surface plasmon polaritons broadband band-stop filter based on EIT effect modulation
Authors: Niu Junhao , Luo Weiyu , Zhu Aijun , Wang Jiajie , Zhang Benxin
Published: March 2021

The filter is one of the most important key elements of electronic circuit. With the rapid development of information, traditional electrical filters can no longer meet the requirements of fast information processing speed and low loss. All optical information processing is considered as one of the solutions to solve this problem. Therefore, there is great significance for studying the all-optical filter. Here, we put forward a kind of broadband band-stop filter which based on surface plasmon polaritons (SPPs) metal - insulator - metal (MIM) modulating by electromagnetically induced transparency (EIT) resonance. We use the finite element method for numerical simulation, and further research on the factors influencing the transmission characteristics of this structure by adjusting the geometric structure. Compared with similar SPPs-based filters, the proposed structure realizes broad stopband, and we can change the EIT resonance to modulate the band-stop filter wavelength range. The proposed broadband band-stop filter based on EIT effect modulation may have great potential in the next generation of all-optical information processing and communication.
The high thermal conductive and flexible boron nitride/silicone rubber composites with segregated structure
Authors: Ding Jiwan , Zheng Ruobing , Zhang Yajie , Zhang Xian , Liu Gang , Zheng Kang
Published: March 2021

Silicone rubber (SR) composites filled with silicone rubber particles (SRP) and functionalized h-BN platelets were successfully prepared, which have high thermal conductivities and flexibility. The functionalization of h-BN adopts the combination of non-covalent and covalent modification. The Non-covalent functionalization of poly(dopamine) (PDA), which is deposited on the surface of h-BN platelets, improves the interfacial adhesion for grafting (3-aminopropyl) triethoxy-silan (KH550) by covalent modification (BN-PDA-KH550). To construct the thermal conductive pathway, silicone rubber particles are added. so that the fillers can distribute along the particle circumference by volume exclusion, which is advantageous for improving heat conduction of SR composites. The as-prepared 30 vol% BN-PDA-KH550@silicone rubber particles/silicone rubber composites (m-BN@SRP/SR) exhibited a relatively high thermal conductivity (2.24 W m−1·K−1), which is about 112 times of pure SR (0.20 W m−1·K−1). Besides, the m-BN@SRP/SR composites possessed satisfactory softness and excellent dielectric properties, which presented a broad application prospect in the field of electronic packaging.
Construction of the targeted and pH-sensitive paclitaxel drug delivery system RGD/PTX@ZIF-90 and anti-tumor activity research
Authors: Ge Fei , Qiao Rui , Song Ping , Tao Yugui , Zhu Longbao , Zhang Weiwei , Li Wanzhen , Gui Lin
Published: March 2021

Tumors area common cause of morbidity and mortality. High treatment efficiency and low drug toxicity are key for effective tumor treatment. Here, the pH-sensitive material ZIF-90 was synthesized by the liquid-phase diffusion method for loading paclitaxel (PTX), and the targeting peptide (RGD) was prepared by the solid-phase synthesis method to modify it (RGD/PTX@ZIF-90). The skeleton of RGD/PTX@ZIF-90 collapses in the acidic tumor microenvironment, thereby releasing PTX and mediating the controlled release of the drug. ZIF-90 below 300 nm was obtained by adjusting the ratio of metal ions and organic ligands in the characterization experiment. In addition, in vitro drug release experiments showed that the drug release rate was greater at pH = 5.5 than at pH = 7.4. The lethal rate of RGD/PTX@ZIF-90 to human breast cancer cells (MCF-7) was 44.5%, which was higher than the lethal rate of PTX alone (37.3%) in the cytotoxicity experiment and apoptosis experiment. Uptake experiments revealed that RGD/PTX@ZIF-90 mainly existed in the cytoplasm of MCF-7, which suggests that the drug had successfully entered the cell to achieve the therapeutic effect. The loading of the nano-medicine carrier ZIF-90 and the modification of the targeting peptide RGD significantly improve the therapeutic effect of PTX and indicate that this system could be used to treat breast cancer.
Pt-Sb2Te as high speed phase-change materials with excellent thermal stability
Authors: Song Zhihao , Guo Junmei , Chen Jialin , Wen Ming , Tan ZhiLong , Wang Chuanjun , Guan Weiming , Zhang Kunhua
Published: March 2021

Phase change memory (PCM) has been regarded as one of the most promising candidates for the next-generation nonvolatile memory. In this paper, we propose PtSb2Te (PST) phase change material for phase change memory. The doping of Pt improves the crystallization temperature and Ten-year data-retention temperature of Sb2Te to 180 °C, 192 °C, 204 °C and 117 °C,123 °C,137 °C, and refines the grain to about 10 nm. At the same time, the density change of Sb2Te film after phase transition is reduced to 4.19% due to the addition of Pt. There are no other new phases formed in PST film except hexagonal Sb2Te phase. For PST-based phase change memory cell, only 10 ns electrical pulse is required to complete the reversible operation with a Reset voltage lower than 4.3 V. At the same time, the number of cycle operations of the memory cell exceeds 105 and it has a lower resistance drift coefficient as 0.019.
Charged surfaces and slabs in periodic boundary conditions
Authors: Rutter M J
Published: March 2021

Plane wave density functional theory codes generally assume periodicity in all three dimensions. This causes difficulties when studying charged systems, for instance energies per unit cell become infinite, and, even after being renormalised by the introduction of a uniform neutralising background, are very slow to converge with cell size. The periodicity introduces spurious electric fields which decay slowly with cell size and which also slow the convergence of other properties relating to the ground state charge density. This paper presents a simple self-consistent technique for producing rapid convergence of both energies and charge distribution in the particular geometry of 2D periodicity, as used for studying surfaces.
On lower bounds for Erdős-Szekeres products
Authors: Billsborough C. , Freedman M. , Hart S. , Kowalsky G. , Lubinsky D. , Pomeranz A. , Sammel A.
Published: March 2021

Let

{

s

j

}

j
=
1

n

\left \{ s_{j}\right \} _{j=1}^{n}

be positive integers. We show that for any

1
≤
L
≤
n
,

1\leq L\leq n,

<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar product Underscript j equals 1 Overscript n Endscripts left-parenthesis 1 minus z Superscript s Super Subscript j Superscript Baseline right-parenthesis double-vertical-bar Subscript upper L Sub Subscript normal infinity Subscript left-parenthesis StartAbsoluteValue z EndAbsoluteValue equals 1 right-parenthesis Baseline greater-than-or-equal-to exp left-parenthesis StartFraction 1 Over 2 e EndFraction StartFraction upper L Over left-parenthesis s 1 s 2 ellipsis s Subscript upper L Baseline right-parenthesis Superscript 1 slash upper L Baseline EndFraction right-parenthesis period">

‖

∏

j
=
1

n

(
1
−

z

s

j

)

‖

L

∞

(

|
z
|

=
1
)

≥
exp
⁡

(

1

2
e

L

(

s

1

s

2

…

s

L

)

1

/

L

)

.

\begin{equation*} \left \Vert \prod _{j=1}^{n}\left ( 1-z^{s_{j}}\right ) \right \Vert _{L_{\infty }\left ( \left \vert z\right \vert =1\right ) }\geq \exp \left ( \frac {1}{2e}\frac {L}{\left ( s_{1}s_{2}\ldots s_{L}\right ) ^{1/L}}\right ) . \end{equation*}

In particular, this gives geometric growth if a positive proportion of the

{

s

j

}

\left \{ s_{j}\right \}

are bounded. We also show that when the

{

s

j

}

\left \{ s_{j}\right \}

grow regularly and faster than

j

(
log
⁡
j
)

2
+
ε

j\left ( \log j\right ) ^{2+\varepsilon }

, some

ε
>
0

\varepsilon >0

, then the norms grow faster than

exp
⁡

(

(
log
⁡
n
)

1
+
δ

)

\exp \left ( \left ( \log n\right ) ^{1+\delta }\right )

for some

δ
>
0

\delta >0

.
On a conjecture by Mbekhta about best approximation by polar factors
Authors: Chiumiento Eduardo
Published: March 2021

The polar factor of a bounded operator acting on a Hilbert space is the unique partial isometry arising in the polar decomposition. It is well known that the polar factor might not be a best approximant to its associated operator in the set of all partial isometries, when the distance is measured in the operator norm. We show that the polar factor of an arbitrary operator

T
T

is a best approximant to

T
T

in the set of all partial isometries

X
X

such that
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="dimension left-parenthesis kernel left-parenthesis upper X right-parenthesis intersection kernel left-parenthesis upper T right-parenthesis Superscript up-tack Baseline right-parenthesis less-than-or-equal-to dimension left-parenthesis kernel left-parenthesis upper X right-parenthesis Superscript up-tack Baseline intersection kernel left-parenthesis upper T right-parenthesis right-parenthesis">

dim
⁡
(
ker
⁡
(
X
)
∩
ker
⁡
(
T

)
⊥

)
≤
dim
⁡
(
ker
⁡
(
X

)
⊥

∩
ker
⁡
(
T
)
)

\dim (\ker (X)\cap \ker (T)^\perp )\leq \dim (\ker (X)^\perp \cap \ker (T))

. We also provide a characterization of best approximations. This work is motivated by a recent conjecture by M. Mbekhta, which can be answered using our results.
Refinements of the Gauss-Lucas theorem using rational lemniscates and polar convexity
Authors: Sendov Hristo
Published: March 2021

The classical Gauss-Lucas theorem for complex polynomialsp(z)≔(z−z1)⋯(z−zn)p(z) ≔(z-z_1) \cdots (z-z_n)states that the critical points ofp(z)p(z)are in the convex hull of its zeros. We give two refinements of the Gauss-Lucas theorem, both connected by the notion of polar convexity.

In the first, we describe lemniscatic regions that do not contain non-trivial critical points of any polynomial of the form<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis z minus z 1 right-parenthesis midline-horizontal-ellipsis left-parenthesis z minus z Subscript m Baseline right-parenthesis left-parenthesis z minus z Subscript m plus 1 Superscript asterisk Baseline right-parenthesis midline-horizontal-ellipsis left-parenthesis z minus z Subscript n Superscript asterisk Baseline right-parenthesis">(z−z1)⋯(z−zm)(z−zm+1∗)⋯(z−zn∗)(z-z_1) \cdots (z-z_m)(z-z^*_{m+1})\cdots (z-z^*_{n}), when the parameterszm+1∗,…,zn∗z^*_{m+1},\ldots ,z^*_{n}vary freely in a specified set, containing the zeroszm+1,…,znz_{m+1},\ldots ,z_{n}.

In the second, we locate the non-trivial critical points ofp(z)p(z)in the intersection ofm+1m+1polar-convex sets, wheremmis the number of distinct zeros ofp(z)p(z). This refinement complements recent ones in Dimitrov [Proc. Amer. Math. Soc. 126 (1998), pp. 2065–2070] and in Curgus and Mascioni [Proc. Amer. Math. Soc. 132 (2004), pp. 2973–2981].
Dynein self-organizes while translocating the centrosome in T-cells
Authors: Gros Oane J. , Damstra Hugo G. J. , Kapitein Lukas C. , Akhmanova Anna , Berger Florian
Published: March 2021

Centrosome translocation upon T-cell activation is constrained by actin reorganization. Consequently, we propose that dynein is attached to mobile anchors in the membrane. Using computer simulations, we find that dynein self-organizes into clusters to form a stalklike microtubule bundle that connects to the centrosome.
Occupational Exposure to Diisocyanates in the European Union
Authors: Rother Dag , Schlüter Urs
Published: March 2021

Objectives

Diisocyanates are a chemical group that are widely used at workplaces in many sectors. They are also potent skin- and respiratory sensitizers. Exposure to diisocyanates is a main cause of occupational asthma in the European Union. To reduce occupational exposure to diisocyanates and consequently the cases of diisocyanate-induced asthma, a restriction on diisocyanates was recently adopted under the REACH Regulation in the European Union.

Methods

A comprehensive evaluation of the data on occupational exposure to the most important diisocyanates at workplaces was made and is reported here. The diisocyanates considered are methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), and hexamethylene diisocyanate (HDI), accounting for more than 95% of the market volume in the EU. The exposure assessment is based on data from Chemical Safety Reports (CSRs) of REACH Registration Dossiers, workplace air monitoring data from Germany, from the UK Health and Safety Executive (HSE), and literature data relevant for the EU, and the USA.

Results

Occupational exposure to diisocyanates is particularly relevant in: (i) C.A.S.E. applications (Coatings, Adhesives, Sealants, Elastomers), (ii) production of polyurethanes (PUs) (e.g. slab-stock foam), (iii) handling of partly uncured PU products (e.g. cutting, demoulding, spray application of foam), and (iv) when diisocyanates/PUs are heated (e.g. hot lamination, foundry applications/casting forms). Ranking of the reported data on inhalation to diisocyanate exposure at workplaces (maximum values) leads to following order: (i) HDI and its oligomers in coatings, (ii) MDI in spray foam applications, (iii) TDI in manufacture of foam, (iv) TDI in manufacture of PUs and PU composite materials, (v) TDI in adhesives, (vi) MDI in adhesives, (vii) MDI in manufacture of PUs and PU composite materials, (viii) TDI in coatings, (ix) MDI in manufacture of foam, and (x) HDI in adhesives.
Performance-Based Everyday Problem-Solving in Patients With TBI
Authors: Pizzi Marcella , Borella Erika , Piras Federica
Published: March 2021

Objective

The present study examined whether the everyday problems test (EPT), a performance-based measure of everyday problem-solving, can be considered a useful test in assessing functional independence in patients with traumatic brain injury (TBI). The relationship between EPT, cognitive abilities (i.e., selective attention, set switching, and working memory) and self-rated measures of everyday functioning and disability in these patients was also assessed.

Method

In this case–control study 25 postcomatose outpatients with TBI (age M = 35.9, SD = 14.21) from a neurorehabilitation unit and 25 matched controls were enrolled. Participants were administered the EPT along with neuropsychological tests of selective attention, set switching and working memory, and self-rated measures of everyday functioning and disability.

Results

Patients with TBI were less accurate and slower than controls in the EPT; the two groups were accurately classified based on EPT completion time (likelihood ratio test χ2 = 28.67, R2 = 0.72, p < .001). In the patient group education and selective attention explained a large portion of variance in EPT accuracy (R2 = 0.53, p = .001), while only selective attention explained a significant portion of variance in EPT time (R2 = 0.24, p < .01). Self-rated measures of everyday functioning and disability did not significantly contribute to EPT performance variance.

Conclusion

Including performance-based measures as the EPT in a multifactorial approach to assessment can be useful for unraveling cognitive factors contributing to TBI’s impact on everyday functioning. Since attentional processes seem to play a significant role in determining EPT performance, rehabilitation of functional independence should target this ability first.
Multimodal Facial Aesthetic Treatment on the Appearance of Aging, Social Confidence, and Psychological Well-being: HARMONY Study
Authors: Cohen Joel L , Rivkin Alexander , Dayan Steven , Shamban Ava , Werschler W Philip , Teller Craig F , Kaminer Michael S , Sykes Jonathan M , Weinkle Susan H , Garcia Julie K
Published: March 2021

Background

A global approach to facial rejuvenation involves multiple treatment modalities.

Objectives

The aim of this study was to evaluate the impact of multimodal facial aesthetic treatment on self-reported psychological and social outcomes.

Methods

HARMONY, a prospective, multicenter, 4-month study, enrolled patients aged 35 to 65 years to receive on-label treatment with a combination of hyaluronic fillers (VYC-20L, HYC-24L, and/or HYC-24L+), onabotulinumtoxinA, and bimatoprost. Fillers were injected on Day 1, with touch-ups performed on Day 14. OnabotulinumtoxinA was injected at Month 3 into glabellar lines and/or crow’s feet lines. Patients applied bimatoprost to eyelashes once daily for 17 weeks. Mean change from baseline on FACE-Q Psychological Well-being and Social Confidence Scales, FACE-Q Aging Appearance Appraisal Scale, and FACE-Q Age Appraisal Visual Analog Scale were assessed.

Results

Of 100 patients treated, 93 were evaluated at 4 months posttreatment. Significant improvement vs baseline was observed on the FACE-Q Scales for Psychological Well-being (mean change, −19.9; P < 0.00001), Social Confidence (mean change, −18.2; P < 0.00001), and Aging Appearance (mean change, −28.5; P < 0.0001). On average, patients’ self-assessed age was 0.1 years older than actual age at baseline and 4.5 years younger at Month 4 (P < 0.001 vs baseline). Forty-two patients experienced adverse events, all mild to moderate.

Conclusions

Multimodal, full facial aesthetic treatment improves patients’ self-reported psychological well-being, social confidence, aging appearance, and perceptions of chronologic age.

Level of Evidence: 4
Critical downstream analysis steps for single-cell RNA sequencing data
Authors: Zhang Zilong , Cui Feifei , Lin Chen , Zhao Lingling , Wang Chunyu , Zou Quan
Published: March 2021

Single-cell RNA sequencing (scRNA-seq) has enabled us to study biological questions at the single-cell level. Currently, many analysis tools are available to better utilize these relatively noisy data. In this review, we summarize the most widely used methods for critical downstream analysis steps (i.e. clustering, trajectory inference, cell-type annotation and integrating datasets). The advantages and limitations are comprehensively discussed, and we provide suggestions for choosing proper methods in different situations. We hope this paper will be useful for scRNA-seq data analysts and bioinformatics tool developers.
Ribo-ODDR: oligo design pipeline for experiment-specific rRNA depletion in Ribo-seq
Authors: Alkan Ferhat , Silva Joana , Pintó Barberà Eric , Faller William J.
Published: March 2021

Motivation

Ribosome Profiling (Ribo-seq) has revolutionized the study of RNA translation by providing information on ribosome positions across all translated RNAs with nucleotide-resolution. Yet several technical limitations restrict the sequencing depth of such experiments, the most common of which is the overabundance of rRNA fragments. Various strategies can be employed to tackle this issue, including the use of commercial rRNA depletion kits. However, as they are designed for more standardized RNAseq experiments, they may perform suboptimally in Ribo-seq. In order to overcome this, it is possible to use custom biotinylated oligos complementary to the most abundant rRNA fragments, however currently no computational framework exists to aid the design of optimal oligos.

Results

Here, we first show that a major confounding issue is that the rRNA fragments generated via Ribo-seq vary significantly with differing experimental conditions, suggesting that a ‘one-size-fits-all’ approach may be inefficient. Therefore we developed Ribo-ODDR, an oligo design pipeline integrated with a user-friendly interface that assists in oligo selection for efficient experiment-specific rRNA depletion. Ribo-ODDR uses preliminary data to identify the most abundant rRNA fragments, and calculates the rRNA depletion efficiency of potential oligos. We experimentally show that Ribo-ODDR designed oligos outperform commercially available kits and lead to a significant increase in rRNA depletion in Ribo-seq.

Availability and implementation

Ribo-ODDR is freely accessible at https://github.com/fallerlab/Ribo-ODDR.

Supplementary information

Supplementary data are available at Bioinformatics online.
Identifiability of causal effects with multiple causes and a binary outcome
Authors: Kong Dehan , Yang Shu , Wang Linbo
Published: March 2021

Unobserved confounding presents a major threat to causal inference in observational studies. Recently, several authors have suggested that this problem could be overcome in a shared confounding setting where multiple treatments are independent given a common latent confounder. It has been shown that under a linear Gaussian model for the treatments, the causal effect is not identifiable without parametric assumptions on the outcome model. In this note, we show that the causal effect is indeed identifiable if we assume a general binary choice model for the outcome with a non-probit link. Our identification approach is based on the incongruence between Gaussianity of the treatments and latent confounder and non-Gaussianity of a latent outcome variable. We further develop a two-step likelihood-based estimation procedure.
Patient-specific mental rehearsal with three-dimensional models before low anterior resection: randomized clinical trial
Authors: Yiasemidou M , Mushtaq F , Basheer M , Galli R , Panagiotou D , Stock S , Preston N , Mon-Williams M , Jayne D G , Miskovic D
Published: March 2021

Background

It was hypothesized that preparing for a surgical procedure, taking into account individual patient characteristics, may facilitate the procedure and improve surgical quality. The aim of this study was to compare different case-specific, preoperative mental rehearsal methods before minimally invasive rectal cancer surgery.

Methods

In this RCT, patients were allocated in a 1 : 1 : 1 : 1 ratio to four groups: systematic mental rehearsal (SMR) using MRI scans; SMR and three-dimensional (3D) virtual models; SMR and synthetic 3D printed models; and routine practice (control group). Surgeons operating on all but the control group underwent mental rehearsal with the visual aids, including axial MRI scans of the pelvis, interactive 3D virtual models reconstructed from axial MRIs, and synthetic models, manufactured by 3D printing. Operations were video-recorded and assessed by two experts blinded to allocation using two validated scores, the Competency Assessment Tool (CAT) and Objective Clinical Human Reliability Analysis (OCHRA). The primary outcome of the study was surgical performance, measured by the CAT.

Results

Forty-nine patients were randomized and allocated to the four groups. There were 12 participants in each of the control, MRI and SMR, and virtual and SMR groups, whereas the SMR using physical models and simulation group included 13. No difference was observed between groups in median CAT scores (control 30.50, MRI 34.25, virtual 31.75, physical 34.00; P = 0.748, partial η2 <0.001, where pη2 is indicative of effect size) or OCHRA scores (anterior, posterior, right and left lateral planes, transection P>0.200, pη2 =0.052–0.088). Time spent not performing dissection was significantly shorter for the SMR with MRI group than for the control (57.5 versus 42 respectively; P < 0.001, pη2 =0.212).

Conclusion

Mental rehearsal did not affect CAT and OCHRA scores of consultant surgeons. Reference number: ISRCTN 75603704 (https://www.isrctn.com).
Digital technology to support lifestyle and health behaviour changes in surgical patients: systematic review
Authors: Robinson A , Husband A K , Slight R D , Slight S P
Published: March 2021

Background

Digital technologies (such as smartphone applications, activity trackers, and e-learning platforms) have supported patients with long-term conditions to change their lifestyle health behaviours. The aim of this study was to examine the effectiveness of digital technologies in supporting patients undergoing elective surgery to change their health behaviours.

Methods

A systematic review was conducted of articles reporting a digital intervention supporting behaviour change in adult patients who underwent elective bariatric, oncological or orthopaedic surgery. MEDLINE, Embase, CINAHL, PsycINFO, Web of Science, and Scopus were searched from inception to March 2019 for quantitative intervention studies with a specific focus on physical activity, dietary intake, and weight loss in patients before and after surgery (PROSPERO: CRD42019127972). The Joanna Briggs Institute critical appraisal checklist was used to assess study quality.

Results

Of 3021 citations screened, 17 studies were included comprising 4923 surgical patients; these included experimental (pre–post design, feasibility studies, and RCTs) and observational studies. Three factors were identified as effective for supporting health behaviour change in elective surgical populations: digital technology delivery, implementation, and theoretical underpinning. Six of eight studies that referred to behaviour change theories observed significant improvements in health behaviour relating to reduced weight regain, and improved lifestyle choices for physical activity and diet. Meta-analysis was not possible because of heterogeneous outcome measures.

Conclusion

Digital technologies may effectively support behavioural change in patients undergoing elective surgery.
Developing implementation strategies to adopt Enhanced Recovery After Surgery (ERAS®) guidelines
Authors: Lam Jennifer Y , Howlett Alexandra , McLuckie Duncan , Stephen Lori M , Else Scott D N , Jones Ashley , Beaudry Paul , Brindle Mary E
Published: March 2021

Background

Strong implementation strategies are critical to the success of Enhanced Recovery after Surgery (ERAS®) guidelines, though little documentation exists on effective strategies, especially in complex clinical situations and unfamiliar contexts. This study outlines the process taken to adopt a novel neonatal ERAS® guideline.

Methods

The implementation strategy was approached in a multi-pronged, concurrent but asynchronous fashion. Between September 2019 and January 2020, healthcare providers from various disciplines and different specialties as well as parents participated in the strategy. Multidisciplinary teams were created to consider existing literature and local contexts including potential facilitators and/or barriers. Task forces worked collaboratively to develop new care pathways. An audit system was developed to record outcomes and elicit feedback for revision.

Results

32 healthcare providers representing 9 disciplines and 5 specialties as well as 8 parents participated. Care pathways and resources were created. Elements recommended for a successful implementation strategy included identification of champions, multidisciplinary stakeholder involvement, consideration of local contexts and insights, patient/family engagement, education, and creation of an audit system.

Conclusion

A multidisciplinary and structured process following principles of implementation science was used to develop an effective implementation strategy for initiating ERAS® guidelines.
Changes in attentional resources during the acquisition of laparoscopic surgical skills
Authors: Thomaschewski M , Heldmann M , Uter J C , Varbelow D , Münte T F , Keck T
Published: March 2021

Background

Increasing familiarity and practice might free up mental resources during laparoscopic surgical skills training. The aim of the study was to track changes in mental resource allocation during acquisition of laparoscopic surgical skills.

Methods

Medical students with no previous experience in laparoscopic surgery took part in a 5-week laparoscopic training curriculum. At the beginning and end of the training period, one of the training tasks was combined with a secondary auditory detection task that required pressing a foot switch for defined target tones, creating a dual-task situation. During execution of the two concurrent tasks, continuous electroencephalographic measurements were made, with special attention to the P300 component, an index of mental resources. Accuracy and reaction times of the secondary task were determined.

Results

All 14 participants successfully completed the training curriculum. Target times for successful completion of individual tasks decreased significantly during training sessions (P  <0.001 for all tasks). Comparing results before and after training showed a significant decrease in event-related brain potential amplitude at the parietal electrode cluster (P300 component, W = 67, P = 0.026), but there were no differences in accuracy (percentage correct responses: W = 48, P = 0.518) or reaction times (W = 42, P = 0.850) in the auditory detection task.

Conclusion

The P300 decrease in the secondary task over training demonstrated a shift of mental resources to the primary task: the surgical exercise. This indicates that, with more practice, mental resources are freed up for additional tasks.
Prevalence and risk factors for thyroid cancer in patients with multinodular goitre
Authors: Apostolou K , Zivaljevic V , Tausanovic K , Zoric G , Chelidonis G , Slijepcevic N , Jovanovic M , Paunovic I
Published: March 2021

Background

Rates of thyroid cancer in patients with multinodular goitre (MNG) vary widely, from 3 per cent in older studies to 35 per cent in more recent studies. The purpose of the present study was to evaluate the prevalence of thyroid cancer in patients operated on for MNG, and to determine risk factors for incidental thyroid malignancy.

Methods

A prospectively developed database of all patients who underwent thyroidectomy for a benign MNG at the high-volume endocrine surgery unit of a tertiary referral university hospital was interrogated.

Results

A total of 3233 patients were analysed, separated into three groups according to their functional thyroid status (hypothyroid, hyperthyroid or euthyroid). There were 2788 women (86.2 per cent); the mean patient age was 56.4 years and mean preoperative disease duration was 106.2 months. Incidental thyroid cancer was identified in 1026 patients (31.7 per cent), of which 917 (89.4 per cent) were papillary cancers. Multivariable regression analysis identified functional thyroid status, younger age, male sex, smaller adenoma size, smaller thyroid glands, Hashimoto’s thyroiditis and chronic non-specific thyroiditis as independent risk factors for thyroid cancer.

Conclusion

MNG was associated with a considerable rate of incidental thyroid cancer, which has been underestimated. A variety of factors should be taken into account when considering the malignant potential of a presumed benign MNG.