bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of compositions from waste of polypropylene and polyethylene terephthalate and research of their technological and thermal properties
Authors: Mukhiddinov Bahodir , Tilavova Lola , Juraev Shokhruh
Published: June 2021

The article presents the results of determining the melting point and the melt flow rate, Vicat heat resistance of a composition made of polypropylene waste from the study of polyethylene terephthalate. It has been established that with an increase in the content of polyethylene terephthalate, the melting point and heat resistance according to Vicat increase, and the melt flow rate of the compositions decreases. The Hildebrand solubility parameters and the packing density of macromolecules are calculated using the increment method. The thermal characteristics of the compositions were investigated by the derivatography method. Their decomposition onset temperature, decomposition rate, and the amount of energy consumed for the decomposition of polymers and polymer compositions were determined. It was revealed that the compositions of polyethylene terephthalate with secondary polypropylene are more thermostable than compositions of polyethylene terephthalate with primary polypropylene.
Study of the composition and properties of vacuum coatings based on titanium carbide
Authors: Saydaxmedov Ravshan , Kadirbekova Kutpnisa
Published: June 2021

Carbide cutting tools are used for machining of machine parts made of complex alloyed materials. Application of protective composite nanostructured coatings on carbide cutting tools allows increasing the service life of cutting tools several times. The coating on their base protects the cobalt binding of carbide alloys. The low thermal conductivity of the composite nanostructured titanium carbide coating means that the heat generated when cutting workpieces is mostly transferred to the chips so that the tool does not become overheated. This is important when machining difficult alloyed, hard-to-machine, ductile materials for which the temperature at the contact zone of the cutting edge and the machined material reaches up to 900°C. The adhesive interaction of the composite nanostructured coating with the substrate material is of no small importance in selecting the coating composition. From this point of view, carbide titanium coatings have good compatibility with carbide cutting tools. Along with this, the study of ion-plasma composite nanostructured coatings based on TiC carbides is relevant. The study results of the composition and properties of vacuum composite nanostructured coatings based on titanium carbides obtained by the ion-plasma method are presented. Studies of the chemical composition, the electronic and atomic structure of composite nanostructured coatings based on Ti carbides were carried out using the HREELS, XPS, and AES method and based on experimental studies of composite nanostructured TiC coatings, the p – T – x diagrams for TiC were refined.
Improving the position of the logistics performance index of Uzbekistan
Authors: Yusufkhonov Zokirkhan , Ravshanov Malik , Kamolov Akmal , Kamalova Elmira
Published: June 2021

The purpose of this article is to propose ways to improve Uzbekistan's position in the World Bank Logistics Performance Index. The logistics performance indicator is based on a global survey of logistics specialists who may have a subjective approach to logistics systems of different countries, which leads to a potential rating. According to the account adopted by the Republic of Uzbekistan in 2018, the index is 2.58. According to the analysis, the highest DL (20.0%) was the score received for organizing the timely delivery of goods. The lowest DL was the assessment of the work of customs authorities (13.5%). Specific problems had been identified, and recommendations had been made to improve Uzbekistan's status. These include the effectiveness of the customs clearance process, quality of infrastructure; ease of international transport and competitive prices; staff qualifications and quality of services; Timely delivery of material flows in the procurement process.
A multi-objective multi-agent optimization algorithm for the multi-skill resource-constrained project scheduling problem with transfer times
Authors: Hosseinian Amir Hossein , Baradaran Vahid
Published: June 2021

This paper addresses the Multi-Skill Resource-Constrained Project Scheduling Problem with Transfer Times (MSRCPSP-TT). A new model has been developed that incorporates the presence of transfer times within the multi-skill RCPSP. The proposed model aims to minimize project’s duration and cost, concurrently. The MSRCPSP-TT is an NP-hard problem; therefore, a Multi-Objective Multi-Agent Optimization Algorithm (MOMAOA) is proposed to acquire feasible schedules. In the proposed algorithm, each agent represents a feasible solution that works with other agents in a grouped environment. The agents evolve due to their social, autonomous, and self-learning behaviors. Moreover, the adjustment of environment helps the evolution of agents as well. Since the MSRCPSP-TT is a multi-objective optimization problem, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is used in different procedures of the MOMAOA. Another novelty of this paper is the application of TOPSIS in different procedures of the MOMAOA. These procedures are utilized for: (1) detecting the leader agent in each group, (2) detecting the global best leader agent, and (3) the global social behavior of the MOMAOA. The performance of the MOMAOA has been analyzed by solving several benchmark problems. The results of the MOMAOA have been validated through comparisons with three other meta-heuristics. The parameters of algorithms are determined by the Response Surface Methodology (RSM). The Kruskal–Wallis test is implemented to statistically analyze the efficiency of methods. Computational results reveal that the MOMAOA can beat the other three methods according to several testing metrics. Furthermore, the impact of transfer times on project’s duration and cost has been assessed. The investigations indicate that resource transfer times have significant impact on both objectives of the proposed model.
Recent Advances of Chlorination in Organic Solar Cells
Authors: He Feng , Wang Hengtao
Published: June 2021

Chlorination has been used in the fields of organic solar cells (OSCs) for a long time, and impressive progress has been made over the years. Recently developed chlorinated OSCs have achieved an efficiency of over 18%. For better understanding and application of chlorination in the fields of OSCs, we will briefly introduce the general properties of chlorine and recent advances in its introduction and applications in OSCs in this cluster article. Finally, we also provide a short discussion of current questions regarding chlorination in OSCs and future developments in this area.
Old Borders and New Horizons in Multimodality Imaging of Malignant Pleural Mesothelioma
Authors: Martini Katharina , Frauenfelder Thomas
Published: June 2021

Background The purpose of this article is to describe the various imaging techniques involved in detection, staging, and preoperative planning in malignant pleural mesothelioma (MPM) focusing on new imaging modalities.

Methods For this purpose, first a brief summary of the etiology of MPM is given. Second, not only the commonly known, but also novel imaging modalities used in MPM will be discussed.

Results A wide range of imaging methods, from conventional chest radiography, through computed tomography and hybrid imaging to radiomics and artificial intelligence, can be used to evaluate MPM.

Conclusion Nowadays multimodality imaging is considered the cornerstone in MPM diagnosis and staging.
Photochemistry of potassium ferrocyanide and its reaction with uridine 5′-monophosphate in aqueous solution under ultraviolet irradiation
Authors: Yang Song-qiu , Zhang Yan , Wang Yan-ni
Published: June 2021

The photochemical reaction of potassium ferrocyanide (K4Fe(CN)6) exhibits excitation wavelength dependence and non-Kasha rule behavior. In this study, the excited-state dynamics of K4Fe(CN)6 were studied by transient absorption spectroscopy. Excited state electron detachment (ESED) and photoaquation reactions were clarified by comparing the results of 260, 320, 340, and 350 nm excitations. ESED is the path to generate a hydrated electron (eaq−). ESED energy barrier varies with the excited state, and it occurs even at the first singlet excited state (1T1g). The 1T1g state shows ∼0.2 ps lifetime and converts into triplet [Fe(CN)6]4− by intersystem crossing. Subsequently, 3[Fe(CN)5]3− appears after one CN− ligand is ejected. In sequence, H2O attacks [Fe(CN)5]3− to generate [Fe(CN)5H2O]3− with a time constant of approximately 20 ps. The 1T1g state and eaq− exhibit strong reducing power. The addition of uridine 5′-monophosphate (UMP) to the K4Fe(CN)6 solution decrease the yield of eaq− and reduce the lifetimes of the eaq− and 1T1g state. The obtained reaction rate constant of 1T1g state and UMP is 1.7×1014 (mol/L)−1·s−1, and the eaq− attachment to UMP is ∼8×109 (mol/L)−1·s−1. Our results indicate that the reductive damage of K4Fe(CN)6 solution to nucleic acids under ultraviolet irradiation cannot be neglected.
A slow and clean fluorine atom beam source based on ultraviolet laser
photolysis
Authors: Wang Yu-feng , Du Tian-yu , Dai Dong-xu , Xiao Chun-lei , Yang Xue-ming
Published: June 2021

A slow and clean fluorine atom beam source is one of the essential components for the low-collision energy scattering experiment involving fluorine atom. In this work, we describe a simple but effective photolysis fluorine atom beam source based on ultraviolet laser photolysis, the performance of which was demonstrated by high-resolution time-of-flight spectra from the reactive scattering of F+HD. This beam source paved the way for studies of low energy collisions with fluorine atoms.
Low loss and dispersion engineered ZnSe waveguides at telecom wavelengths
Authors: Fang Yiming , Yang Zhen , Li Chengdong , Xu Peipeng , Yan Kunlun , Sheng Yan , Tao Haizheng , Wang Rongping
Published: June 2021

We have successfully fabricated a dispersion engineered ZnSe waveguide. The ZnSe film was deposited on a CaF2 substrate by radio frequency magnetron sputtering, and the waveguide was patterned directly on the ZnSe films by UV lithography and inductively coupled plasma etching. The nonlinear coefficient in the 4-μm-width waveguide was calculated to be 0.73 w−1 m−1 for both TE and TM modes at 1.55 µm. The loss of the ZnSe rib waveguides was measured to be 4.3 dB/cm at 1550 nm using the cut-back method.
Current–voltage characteristics and breakdown of different structural planar microelectrodes in atmospheric air
Authors: Zhang J. F. , Zhang D. W. , Wu X. W. , Ren Q. L. , Qu Z. G.
Published: June 2021

With the development of applications for microelectromechanical system (MEMS) components and micromachining technology, planar microelectrodes have attracted considerable interest. To study the discharge characteristics of these structures, planar microelectrodes with a variety of plate-shaped and needle-shaped microelectrode structures fabricated from indium tin oxide (ITO) and copper (Cu) with microelectrode gaps ranging from 5 to 35 µm were manufactured using MEMS technology in this study. Experiments carried out in atmospheric air show that the microelectrode configuration has a crucial impact on the discharge current, breakdown voltage, and current response to varying electrode gaps. The electrode surface area plays a significant role in the discharge characteristics of planar microelectrodes, which is a factor dominating the discharge current and breakdown voltage. The commonly used formulas in macroscale corona discharge cannot be directly applied to planar microelectrodes. Planar microelectrodes fabricated with Cu on Si substrates have larger discharge currents, higher breakdown voltages, and better resistance to breakdown strength than ITO ones on quartz substrates under nA-scale current, while ITO damaged microelectrodes because of breakdown can still discharge when accompanied by different discharge characteristics.
A third-order magnetic gradient tensor optimization algorithm based on the second-order improved central difference method
Authors: Wang Bo , Ren Guoquan , Li Zhining , Li Qingzhu
Published: June 2021

An improved method based on the second order improved central difference method is proposed to improve the third-order magnetic gradient tensor, which is affected by noise and characterized by poor stability. The third-order magnetic gradient tensor at the center point is calculated by using the three-component magnetic field at four points along a single route; this approach effectively improves the stability of the third-order magnetic gradient tensor data. In this paper, the errors of the traditional method and the new method in calculating the third-order magnetic gradient tensor are given by the Taylor series. Based on the traditional third-order magnetic gradient tensor system, a new third-order magnetic gradient tensor system and the corresponding measurement method are presented. Through simulations, in the case of noise, it is verified that the proposed method exhibits better stability by comparing the components of the third-order magnetic gradient tensor with the positioning results. In experiments, the root-mean-square error is used to compare the positioning results before and after noise addition. The traditional method changes the root-mean-square error of the positioning results from (1.3626, 3.6573, 0.5766 m) to (3.3661, 9.5966, 1.9465 m), and the root-mean-square error obtained with the new method displays no obvious change.
Complementary frequency electromagnetic gyroscope
Authors: Xu Zhendong , Zhang Yingchun , Xu Guodong
Published: June 2021

This paper proposes a complementary frequency electromagnetic gyroscope. In this gyroscope, a voltage-controlled oscillator (VCO) is applied to generate complementary frequency signals and the angular rate detection is realized based on a phase-locked loop. The complementary frequency electromagnetic gyroscope can be fully realized by micro-electronic technology, which is beneficial to the miniaturization of the angular rate measurement system and has a wide application prospect. The complementary frequency electromagnetic gyroscope extends the application of the Sagnac effect and replaces the optical signal with the electromagnetic pulse signal. It can make full use of the advantages of microelectronic technology and microwave technology to realize the miniaturization of measuring components and even realize the system on a chip. In this paper, the mathematical model of the complementary frequency electromagnetic gyroscope is established and verified by simulation analysis. Theoretical analysis shows that the measured angular rate is proportional to the relative frequency difference of complementary VCO output. The simulation results indicate that the sensitivity of the complementary frequency gyroscope is 1 × 10−5 rad/s and is insensitive to noise. When the signal-to-noise ratio is lower than 0 dB, the gyroscope still has good angular rate measurement accuracy.
Realising equal-strength welding with good conductivity in Cu–Cr–Zr alloy via friction stir welding
Authors: Wang Y.D. , Zhu S.Z. , Xie G.M. , Wu L.H. , Xue P. , Ni D.R. , Xiao B.L. , Ma Z.Y.
Published: June 2021

Realising high-quality welding of the peak aged Cu–Cr–Zr alloy has always been a big challenge. Under a low rotation rate of 400 rev min−1, equiaxed ultrafine grains together with nanoscale precipitates with comparable size to that of the peak aged state were obtained in the nugget zone of the friction stir welded joint. Further, the initial strengthened precipitates were also preserved near the nugget zone, neither dissolved nor coarsened. Therefore, softening zone disappeared and a high-quality weld with equal strength to the base material was first achieved. Furthermore, the electrical conductivity of the joint was hardly weakened. This study provides an effective method to improve the strength and electrical conductivity of the precipitation-hardened Cu alloy joints.
High spin pumping efficiency in Fe80Co20/Ta bilayers
Authors: Velázquez Rodriguez D , Gómez J E , Morbidel L , Costanzo Caso P A , Milano J , Butera A
Published: June 2021

We have investigated the spin pumping phenomenon in Fe80Co20/Ta bilayers of different thicknesses in which the ferromagnet grows epitaxially on MgO substrates. We have obtained a Gilbert damping constant for Fe80Co20 as low as α = 1.3(1) × 10−3, which is smaller than values generally reported in metallic ferromagnets. From the dependence of α with the Fe80Co20 thickness, we extracted the value of the effective spin mixing conductance

g

↑↓

= 5.7(3) × 1014 cm−2. Analyzing the Ta and Fe80Co20 thickness dependence of the inverse spin Hall effect voltage, we obtained the transport parameters

λ

sd

= 1.1(3) nm and

Θ

SH

= –0.024(3). We have developed an expression to quantify the efficiency of the spin pumping phenomenon in ferromagnetic/nonmagnetic metal bilayers. The calculated efficiency shows that the Fe80Co20/Ta system is up to an order of magnitude more efficient than other metallic ferromagnetic bilayers reported in the literature.
Dose–effect relationships for PBM in the treatment of Alzheimer’s disease
Authors: Zhang Renlong , Zhou Ting , Liu Liwei , Ohulchanskyy Tymish Y , Qu Junle
Published: June 2021

Alzheimer’s disease (AD) has become one of the most worrying health conditions with no effective treatment available with the increase in population aging. A large number of clinical studies and experiments proved that photobiomodulation (PBM) had a positive effect on AD treatment. The irradiation with red and near-infrared light at a low dose can effectively reduce an accumulation of amyloid-β(Aβ) plaques in the central nervous system, relieving the symptoms of AD. This review summarizes the parameters of PBM for AD treatment studied on cells, animals, and in clinical trials, as well as the dose–effect relationship of PBM treatment for AD. The mechanisms of PBM on the cellular level, which include regulation of microglia and astrocytes that may affect Aβplaque elimination are also discussed.
Enhancing the quality of self-organized nanoripples by Ar-ion bombardment of a bilayer system
Authors: Li Jinyu , Yang Gaoyuan , Bradley R Mark , Liu Ying , Frost Frank , Hong Yilin
Published: June 2021

Ion bombardment (IB) is a promising nanofabrication technique for producing nanoripples. A critical issue that restricts the application of IB is the limited quality of IB-induced nanoripples. Photoresist (PR) and antireflection coating (ARC) are of technological relevance for lithographic exposure processes. Moreover, to improve the quality of IB-induced self-organized nanoripples, in this study, a PR/ARC bilayer was bombarded at an incidence angle of 50°. The surface normalized defect density and power spectral density, obtained via scanning atomic force microscopy, indicate the superiority of the PR/ARC bilayer nanoripples over those of single PR or ARC layers. The growth mechanism of the improved nanoripples, deciphered via the temporal evolution of the morphology, involves the following processes: (i) formation of a well-grown IB-induced nanoripple prepattern on the PR, (ii) transfer of nanoripples from the PR to the ARC, forming an initial ARC nanoripple morphology for subsequent IB, and (iii) conversion of the initial nonuniform ARC nanoripples into uniform nanoripples. In this unique method, the angle of ion-incidence should be chosen so that ripples form on both PR and ARC films. Overall, this method facilitates nanoripple improvement, including prepattern fabrication for guiding nanoripple growth and sustainable nanoripple development via a single IB. Thus, the unique method presented in this study can aid in advancing academic research and also has potential applications in the field of IB-induced nanoripples.
Broadband quantum memory in a cavity via zero spectral dispersion
Authors: Moiseev E S , Tashchilina Arina , Moiseev S A , Sanders Barry C
Published: June 2021

We seek to design experimentally feasible broadband, temporally multiplexed optical quantum memory with near-term applications to telecom bands. Specifically, we devise dispersion compensation (DC) for an impedance-matched narrow-band quantum memory by exploiting Raman processes over two three-level atomic subensembles, one for memory and the other for DC. DC provides impedance matching over more than a full cavity linewidth. Combined with 1 s spin-coherence lifetime the memory could be capable of power efficiency exceeding 90% leading to 106 modes for temporal multiplexing. Our design could lead to significant multiplexing enhancement for quantum repeaters to be used for telecom quantum networks.
W7-X and the sawtooth instability: towards realistic simulations of current-driven magnetic reconnection
Authors: Zocco Alessandro , Mishchenko Alexey , Nührenberg Carolin , Könies Axel , Kleiber Ralf , Borchardt Matthias , Slaby Christoph , Zanini Marco , Stange Torsten , Laqua Heinrich Peter , Rahbarnia Kian , Thomsen Henning , Wolf R.C. , Helander Per , Hatzky Roman , Cole Michael D. J.
Published: June 2021

Magnetic reconnection in W7-X is studied by means of global numerical simulations in a series of models of increasing complexity. The magnetic geometry ranges from that of a cylinder to the full three-dimensional field of W7-X, and the equations solved range from ideal magnetohydrodynamics (MHD) to gyrokinetics. We simulate plasmas from the first operation phase with electron cyclotron current drive (ECCD). These are characterized by an equilibrium magnetic field featuring an ECCD-distorted ‘humped’ profile of the rotational transformι, withι= 1 in two radial locations. Such plasmas generally show sawtooth activity, hence motivating the present study. We pay particular attention to the role of equilibrium current density gradients in the destabilization of reconnecting modes. When the equilibrium temperature and density gradients are artificially suppressed (to eliminate the pressure gradient drive), the perturbed electrostatic potential is radially localized between the locations at whichι= 1. This is shown with a purely collisionless gyrokinetic model, in cylindrical geometry. In the real toroidal geometry of W7-X, for a non-ideal MHD model including a uniform resistivity, electron inertia and (numerical) viscosity, the same qualitative behaviour is observed. In particular, even if a resonant (m,n) = (1, −1) perturbation is initialized, the most unstable mode is the (m,n) = (−4, 4), wheremandnare the poloidal and toroidal mode numbers, respectively. Other modes are destabilized due to geometric coupling. The growth rate of this instability scales asη1/3, whereηis the plasma resistivity, thus suggesting that ECCD drives ideal MHD stable W7-X plasmas towards non-ideal marginality. An ideal magnetohydrodynamic analysis confirms the result. A fluid-kinetic hybrid version of theEUTERPEcode shows that gyrokinetic ions have a stabilizing effect on these modes. For W7-X relevant collisionalities, the growth rate scales linearly with the electron skin depth,de. Implications of our results for sawtoothing W7-X operation are discussed.
Climate impact of aircraft-induced cirrus assessed from satellite observations before and during COVID-19
Authors: Quaas Johannes , Gryspeerdt Edward , Vautard Robert , Boucher Olivier
Published: June 2021

Aircraft produce condensation trails, which are thought to increase high-level cloudiness under certain conditions. However the magnitude of such an effect and whether this contributes substantially to the radiative forcing due to the aviation sector remain uncertain. The very substantial, near-global reduction in air traffic in response to the COVID-19 outbreak offers an unprecedented opportunity to identify the anthropogenic contribution to the observed cirrus coverage and thickness. Here we show, using an analysis of satellite observations for the period March–May 2020, that in the 20% of the Northern Hemisphere mid-latitudes with the largest air traffic reduction, cirrus fraction was reduced by ∼9 ± 1.5% on average, and cirrus emissivity was reduced by ∼2 ± 5% relative to what they should have been with normal air traffic. The changes are corroborated by a consistent estimate based on linear trends over the period 2011–2019. The change in cirrus translates to a global radiative forcing of 61 ± 39 mW m−2. This estimate is somewhat smaller than previous assessments.
Association of personal network attributes with clean cooking adoption in rural South India
Authors: Kumar Praveen , McCafferty Liam , Dhand Amar , Rao Smitha , Díaz-Valdés Antonia , Tabak Rachel G , Brownson Ross C , Yadama Gautam N
Published: June 2021

Adoption of liquefied petroleum gas (LPG) is the primary policy approach in India to transition rural poor communities toward clean cooking behavior. Prior clean cooking studies show that affordability, accessibility, and awareness impact LPG adoption in India. There is scarce research that explores the association of personal networks of community members in their LPG adoption. In this cross-sectional study, we use standard egocentric personal network analyses and multivariate logistic regression models to examine the association of structure and composition of personal networks with LPG adoption in poor communities. Our results show that higher proportions of peers owning LPG are associated with higher likelihood of LPG ownership in the respondents (OR = 41.30, 95% confidence interval: 16.86–101.20, p = 0.00). This study on personal network characteristics in clean cooking research offers a germane foundation for further large scale personal network studies on clean cooking adoption in poor communities.
Climate sensitivity indices and their relation with projected temperature change in CMIP6 models
Authors: Huusko Linnea L , Bender Frida A-M , Ekman Annica M L , Storelvmo Trude
Published: June 2021

Equilibrium climate sensitivity (ECS) and transient climate response (TCR) are both measures of the sensitivity of the climate system to external forcing, in terms of temperature response to CO2 doubling. Here it is shown that, of the two, TCR in current-generation coupled climate models is better correlated with the model projected temperature change from the pre-industrial state, not only on decadal time scales but throughout much of the 21st century. For strong mitigation scenarios the difference persists until the end of the century. Historical forcing on the other hand has a significant degree of predictive power of past temperature evolution in the models, but is not relevant to the magnitude of temperature change in their future projections. Regional analysis shows a superior predictive power of ECS over TCR during the latter half of the 21st century in areas with slow warming, illustrating that although TCR is a better predictor of warming on a global scale, it does not capture delayed regional feedbacks, or pattern effects. The transient warming at CO2 quadrupling (T140) is found to be correlated with global mean temperature anomaly for a longer time than TCR, and it also better describes the pattern of regional temperature anomaly at the end of the century. Over the 20th century, there is a weak correlation between total forcing and ECS, contributing to, but not determining, the model agreement with observed warming. ECS and aerosol forcing in the models are not correlated.
Double network laminarin-boronic/alginate dynamic bioink for 3D bioprinting cell-laden constructs
Authors: Amaral Adérito J R , Gaspar Vítor M , Lavrador Pedro , Mano João F
Published: June 2021

The design of dynamically crosslinked hydrogel bioinks for three-dimensional (3D) bioprinting is emerging as a valuable strategy to advance the fabrication of mechanically tuneable cell-laden constructs for 3D in vitro disease modelling and tissue engineering applications. Herein, a dynamic bioink comprising boronic acid-functionalised laminarin and alginate is explored for bioprinting 3D constructs under physiologically relevant conditions. The formulated bioink takes advantage of a double crosslinked network that combines covalent but reversible boronate ester bonds and ionic gelation via divalent cations. Moreover, it exhibits suitable rheological properties and improved mechanical features owing to its modular crosslinking chemistry, yielding stable constructs with user-programmable architecture. We explored such dynamic bioink as a supporting matrix for different cell classes, namely osteoblast precursors, fibroblasts and breast cancer cells. The resulting cell-laden bioprinted hydrogels display a homogeneous cell distribution post-printing and exceptional cell viability (>90%) that can be maintained for prolonged time periods in culture (14 days) for all cell lines. This simple and chemically versatile approach is envisaged to accelerate the development of multifunctional bioinks and contribute towards the fabrication of biomimetic 3D scaffolds with applicability in a wide range of predictive or exploratory biomedical platforms.
Cellulose-based scaffolds enhance pseudoislets formation and functionality
Authors: Velasco-Mallorquí Ferran , Rodríguez-Comas Júlia , Ramón-Azcón Javier
Published: June 2021

In vitro research for the study of type 2 diabetes (T2D) is frequently limited by the availability of a functional model for islets of Langerhans. To overcome the limitations of obtaining pancreatic islets from different sources, such as animal models or human donors, immortalized cell lines as the insulin-producing INS1E β-cells have appeared as a valid alternative to model insulin-related diseases. However, immortalized cell lines are mainly used in flat surfaces or monolayer distributions, not resembling the spheroid-like architecture of the pancreatic islets. To generate islet-like structures, the use of scaffolds appeared as a valid tool to promote cell aggregations. Traditionally-used hydrogel encapsulation methods do not accomplish all the requisites for pancreatic tissue engineering, as its poor nutrient and oxygen diffusion induces cell death. Here, we use cryogelation technology to develop a more resemblance scaffold with the mechanical and physical properties needed to engineer pancreatic tissue. This study shows that carboxymethyl cellulose (CMC) cryogels prompted cells to generate β-cell clusters in comparison to gelatin-based scaffolds, that did not induce this cell organization. Moreover, the high porosity achieved with CMC cryogels allowed us to create specific range pseudoislets. Pseudoislets formed within CMC-scaffolds showed cell viability for up to 7 d and a better response to glucose over conventional monolayer cultures. Overall, our results demonstrate that CMC-scaffolds can be used to control the organization and function of insulin-producing β-cells, representing a suitable technique to generate β-cell clusters to study pancreatic islet function.
𝒵-stability of transformation group C*-algebras
Authors: Niu Zhuang
Published: June 2021

Let

(
X
,
Γ
)

(X, \Gamma )

be a free and minimal topological dynamical system, where

X
X

is a separable compact Hausdorff space and

Γ
\Gamma

is a countable infinite discrete amenable group. It is shown that if

(
X
,
Γ
)

(X, \Gamma )

has the Uniform Rokhlin Property (URP) and Cuntz comparison of open sets (COS), then

m
d
i
m

(
X
,
Γ
)
=
0

\mathrm {mdim}(X, \Gamma )=0

implies that
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis normal upper C left-parenthesis upper X right-parenthesis right-normal-factor-semidirect-product normal upper Gamma right-parenthesis circled-times script upper Z approximately-equals normal upper C left-parenthesis upper X right-parenthesis right-normal-factor-semidirect-product normal upper Gamma">

(

C

(
X
)
⋊
Γ
)
⊗

Z

≅

C

(
X
)
⋊
Γ

(\mathrm {C}(X) \rtimes \Gamma )\otimes \mathcal Z \cong \mathrm {C}(X) \rtimes \Gamma

, where

m
d
i
m

\mathrm {mdim}

is the mean dimension of

(
X
,
Γ
)

(X, \Gamma )

,

Z

\mathcal Z

is the Jiang-Su algebra, and

C

(
X
)
⋊
Γ

\mathrm {C}(X) \rtimes \Gamma

is the transformation group C*-algebra of

(
X
,
Γ
)

(X, \Gamma )

. In particular, in this case,

m
d
i
m

(
X
,
Γ
)
=
0

\mathrm {mdim}(X, \Gamma )=0

implies that the C*-algebra

C

(
X
)
⋊
Γ

\mathrm {C}(X) \rtimes \Gamma

is classified by the Elliott invariant.
Will Podcasting and Social Media Replace Journals and Traditional Science Communication? No, but...
Authors: Fox Matthew P , Carr Kareem , D’Agostino McGowan Lucy , Murray Eleanor J , Hidalgo Bertha , Banack Hailey R
Published: June 2021

The digital world in which we live is changing rapidly. The evolving media environment is having a direct impact on traditional forms of communication and knowledge translation in public health and epidemiology. Openly accessible digital media can be used to reach a broader and more diverse audience of trainees, scientists, and the lay public than can traditional forms of scientific communication. The new digital landscape for delivering content is vast, and new platforms are continuously being added. In this article, we focus on several, including Twitter and podcasting, and discuss their relevance to epidemiology and science communication. We highlight 3 key reasons why we think epidemiologists should be engaging with these mediums: 1) science communication, 2) career advancement, and 3) development of a community and public service. Other positive and negative consequences of engaging in these forms of new media are also discussed. The authors of this commentary are all engaged in social media and podcasting for scientific communication, and we reflect on our experiences with these mediums as tools to advance the field of epidemiology.
The mutation of Thr315 to Asn of GH10 xylanase XynR increases the alkaliphily but decreases the alkaline resistance
Authors: Kuwata Kohei , Suzuki Manami , Takita Teisuke , Yatsunami Rie , Nakamura Satoshi , Yasukawa Kiyoshi
Published: June 2021

XynR is a thermophilic and alkaline GH10 xylanase, identified in the culture broth of alkaliphilic and thermophilic Bacillus sp. strain TAR-1. We previously selected S92E as a thermostable variant from a site saturation mutagenesis library. Here, we attempted to select the alkaliphilic XynR variant from the library and isolated T315N. In the hydrolysis of beechwood xylan, T315N and S92E/T315N exhibited a broader bell-shaped pH-dependent activity than the wild-type (WT) XynR and S92E. The optimal pH values of T315N and S92E/T315N were 6.5-9.5 while those of WT and S92E were 6.5-8.5. On the other hand, T315N and S92E/T315N exhibited a narrower bell-shaped pH dependence of stability: the pHs at which the activity was stable after the incubation at 37 °C for 24 h were 6.0-8.5 for T315N and S92E/T315N, but 6.0-10.0 for WT and S92E. These results indicated that the mutation of Thr315 to Asn increased the alkaliphily but decreased the alkaline resistance.
Treatment Practices for Adults With Candidemia at 9 Active Surveillance Sites—United States, 2017–2018
Authors: Gold Jeremy A W , Seagle Emma E , Nadle Joelle , Barter Devra M , Czaja Christopher A , Johnston Helen , Farley Monica M , Thomas Stepy , Harrison Lee H , Fischer Jill , Pattee Brittany , Mody Rajal K , Phipps Erin C , Davis Sarah Shrum , Tesini Brenda L , Zhang Alexia Y , Markus Tiffanie M , Schaffner William , Lockhart Shawn R , Vallabhaneni Snigdha , Jackson Brendan R , Lyman Meghan
Published: June 2021

Background

Candidemia is a common opportunistic infection causing substantial morbidity and mortality. Because of an increasing proportion of non-albicans Candida species and rising antifungal drug resistance, the Infectious Diseases Society of America (IDSA) changed treatment guidelines in 2016 to recommend echinocandins over fluconazole as first-line treatment for adults with candidemia. We describe candidemia treatment practices and adherence to the updated guidelines.

Methods

During 2017–2018, the Emerging Infections Program conducted active population-based candidemia surveillance at 9 US sites using a standardized case definition. We assessed factors associated with initial antifungal treatment for the first candidemia case among adults using multivariable logistic regression models. To identify instances of potentially inappropriate treatment, we compared the first antifungal drug received with species and antifungal susceptibility testing (AFST) results from initial blood cultures.

Results

Among 1835 patients who received antifungal treatment, 1258 (68.6%) received an echinocandin and 543 (29.6%) received fluconazole as initial treatment. Cirrhosis (adjusted odds ratio = 2.06; 95% confidence interval, 1.29–3.29) was the only underlying medical condition significantly associated with initial receipt of an echinocandin (versus fluconazole). More than one-half (n = 304, 56.0%) of patients initially treated with fluconazole grew a non-albicans species. Among 265 patients initially treated with fluconazole and with fluconazole AFST results, 28 (10.6%) had a fluconazole-resistant isolate.

Conclusions

A substantial proportion of patients with candidemia were initially treated with fluconazole, resulting in potentially inappropriate treatment for those involving non-albicans or fluconazole-resistant species. Reasons for nonadherence to IDSA guidelines should be evaluated, and clinician education is needed.
Coaching Caregivers of Children who are Deaf or Hard of Hearing: A Scoping Review
Authors: Noll Dorie , DiFabio Danielle , Moodie Sheila , Graham Ian D , Potter Beth , Grandpierre Viviane , Fitzpatrick Elizabeth M
Published: June 2021

Caregiver coaching is an expected practice in early intervention. However, little is known about coaching with caregivers of children who are deaf or hard of hearing, receiving services for listening and spoken language (LSL). A systematic review of 7 databases, the gray literature, and consultation with 7 expert LSL practitioners yielded 506 records for full-text review, 22 of which were ultimately included in the review. Our findings are presented as 3 themes: coaching practices, training for coaching, and effectiveness of coaching. Eight models of coaching were identified in the literature, from which we identified commonalities to propose a consolidated model that illustrates the recommendations and process of caregiver coaching found in the LSL literature.
Ethnic Violence Across Space
Authors: Mueller Hannes , Rohner Dominic , Schönholzer David
Published: June 2021

Spatial analyses focus to a large extent on the ‘bright side of proximity’, namely voluntary (positive-sum) interactions such as, e.g., in trade and innovation. In contrast, the violent ‘dark side of proximity’ has often been overlooked. To address this gap, we study the role of spatial proximity in ethnic conflict, developing a structural model of spatial violence in which ethnic groups recruit fighters strategically across space. The spatial decay of violence determines the equilibrium placement of fighters and drives specific spatial patterns of conflict. The structural parameters of the model are estimated using fine-grained data on ethnic groups and violence from twenty-four ethnically divided countries. We find that in more than half of these, spatial decay is substantial: half of all ethnic violence dissipates after 350 km. Violence is asymmetric, is higher near ethnic borders and typically originates from outside a location. Counterfactual estimates suggest that setting up barriers would reduce violence, but pacifying groups suffering from grievances would often be more effective.
‘It takes a village’: a qualitative study on malnutrition and oral nutritional supplements with older adults in Ireland
Authors: Reynolds Ciara M E , Dominguez Castro Patricia , Geraghty Aisling A , Browne Sarah , Bardon Laura A , Corish Clare A
Published: June 2021

Background

Malnutrition affects approximately 20% of older adult populations in Europe, yet their views on the condition are rarely explored. This qualitative study aimed to explore the experiences of older adults living with malnutrition and prescribed oral nutritional supplements in the community setting.

Methods

Semi-structured individual interviews were used to collect data from 13 community-dwelling individuals aged ≥60 years with a current or previous prescription for oral nutritional supplements. Self-perceived health status was measured using the EuroQol EQ-5D-5L, a short questionnaire and visual analogue scale. Interviews were audio-recorded and transcribed verbatim. Interview data were organized using NVivo 12 and analyzed using inductive thematic analysis.

Results

Median age was 80.0 (interquartile range 19.5) years, seven were male and six were female. Median health score was 60.0 (interquartile range 35.0) out of 100. Almost one-third reported severe or extreme problems with usual activities, and pain or discomfort. One main theme was identified from the interviews: ‘It takes a village’, with four subthemes (i) ‘I get by with a little help from my friends’, (ii) ‘The obvious diagnosis’, (iii) ‘The missing T in MDT’ and (iv) ‘Confusion’. Participants with malnutrition reported relying on friends, family and carers with poor multidisciplinary team communication and lack of dietetic support.

Conclusions

Participants in this study experienced poor management of malnutrition with missing links between the hospital and community healthcare settings, and lack of dietetic services. Patient views should be used to inform public health guidelines and guide future interventions in the community to improve the health status of older adults with malnutrition.
Oral administration of camellia oil ameliorates obesity and modifies the gut microbiota composition in mice fed a high-fat diet
Authors: Huang Tianyang , Zhou Weikang , Ma Xiangguo , Jiang Jianhui , Zhang Fuan , Zhou Wanmeng , He Hao , Cui Guozhen
Published: June 2021

Obesity, which is often caused by adipocyte metabolism dysfunction, is rapidly becoming a serious global health issue. Studies in the literature have shown that camellia oil (Camellia oleifera Abel) exerted potential lipid regulation and other multiple biological activities. Here, we aimed to investigate the effects of camellia oil on obese mice induced by a high-fat diet and to explore gut microbiota alterations after camellia oil intervention. The results showed that oral administration of camellia oil dramatically attenuated the fat deposits, serum levels of the total cholesterol, triacylglycerol, low-density lipoprotein cholesterol, fasting plasma glucose, the atherosclerosis index, the hepatic steatosis and inflammation in high-fat diet-induced obese mice. Meanwhile, the high-density lipoprotein cholesterol level in obese mice was enhanced after the camellia oil treatment. Furthermore, 16S rRNA analysis showed that certain aspects of the gut microbiota, especially the gut microbiota diversity and the relative abundance of Actinobacteria, Coriobacteriaceae, Lactobacillus and Anoxybacillus, were significantly increased by camellia oil treatment while the ratio of Firmicutes to Bacteroidetes was decreased. Taken together, our finding suggested that camellia oil was a potential dietary supplement and functional food for ameliorating fat deposits, hyperglycemia and fatty liver, probably by modifying the gut microbiota composition.
Impact of abortion law reforms on health services and health outcomes in low- and middle-income countries: a systematic review
Authors: Ishola Foluso , Ukah U Vivian , Alli Babatunde Y , Nandi Arijit
Published: June 2021

While restrictive abortion laws still prevail in most low- and middle-income countries (LMICs), many countries have reformed their abortion laws, expanding the grounds on which abortion can be performed legally. However, the implications of these reforms on women’s access to and use of health services, as well as their health outcomes, are uncertain. This systematic review aimed to evaluate and synthesize empirical research evidence concerning the effects of abortion law reforms on women’s health services and health outcomes in LMICs. We searched Medline, Embase, CINAHL and Web of Science databases, as well as grey literature and reference lists of included studies. We included pre–post and quasi-experimental studies that aimed to estimate the causal effect of a change in abortion law on at least one of four outcomes: (1) use of and access to abortion services, (2) fertility rates, (3) maternal and/or neonatal morbidity and mortality and (4) contraceptive use. We assessed the quality of studies using the quasi-experimental study design series checklist and synthesized evidence through a narrative description. Of the 2796 records identified by our search, we included 13 studies in the review, which covered reforms occurring in Uruguay, Ethiopia, Mexico, Nepal, Chile, Romania, India and Ghana. Studies employed pre–post, interrupted time series, difference-in-differences and synthetic control designs. Legislative reforms from highly restrictive to relatively liberal were associated with reductions in fertility, particularly among women from 20 to 34 years of age, as well as lower maternal mortality. Evidence regarding the impact of abortion reforms on other outcomes, as well as whether effects vary by socioeconomic status, is limited. Further research is required to strengthen the evidence base for informing abortion legislation in LMICs. This review explicitly points to the need for rigorous quasi-experimental studies with sensitivity analyses to assess underlying assumptions. The systematic review was registered in PROSPERO database CRD42019126927.
Integrable reduction and solitons of the Fokas–Lenells equation
Authors: Horikis Theodoros P
Published: June 2021

Novel soliton structures are constructed for the Fokas–Lenells equation. In so doing, and after discussing the stability of continuous waves, a multiple scales based perturbation theory is used to reduce the equation to a Korteweg–de Vries system whose single soliton solution gives rise to intricate (and rather unexpected) solutions to the original system. Both the focusing and defocusing equations are considered and it is found that dark solitons may exist in both cases while in the focusing case antidark solitons are also possible. These findings are quite surprising as the relative nonlinear Schrödinger equation does not exhibit these solutions. So far, similar abundance of solutions has only been observed in relative coupled systems.
Precise or Imprecise Probabilities? Evidence from Survey Response Related to Late-Onset Dementia
Authors: Giustinelli Pamela , Manski Charles F , Molinari Francesca
Published: June 2021

We elicit numerical expectations for late-onset dementia and long-term-care (LTC) outcomes in the US Health and Retirement Study. We provide the first empirical evidence on dementia-risk perceptions among dementia-free older Americans and establish important patterns regarding imprecision of subjective probabilities. Our elicitation distinguishes between precise and imprecise probabilities, while accounting for rounding of reports. Imprecise-probability respondents quantify imprecision using probability intervals. Nearly half of respondents hold imprecise dementia and LTC probabilities, while almost a third of precise-probability respondents round their reports. These proportions decrease substantially when LTC expectations are conditioned on hypothetical knowledge of the dementia state. Among rounding and imprecise-probability respondents, our elicitation yields two measures: an initial rounded or approximated response and a post-probe response, which we interpret as the respondent's true point or interval probability. We study the mapping between the two measures and find that respondents initially tend to over-report small probabilities and under-report large probabilities. Using a specific framework for study of LTC insurance choice with uncertain dementia state, we illustrate the dangers of ignoring imprecise or rounded probabilities for modeling and prediction of insurance demand.