bluuebunny/crossref_metadata_2025 huggingface dataset:
An all-in-one approach for synthesis and functionalization of nano colloidal gold with acetylacetone
Authors: Zhang Li , Zheng Hongcen , Gan Yonghai , Wu Bingdang , Chen Zhihao , Wei Shuangshuang , Zhang Guoyang , Zhang Shujuan , Pan Bingcai , Chen Chuncheng
Published: November 2021

Controllable synthesis, proper dispersion, and feasible functionalization are crucial requirements for the application of nanomaterials in many scenarios. Here, we report an all-in-one approach for the synthesis and functionalization of gold nanoparticles (AuNPs) with the simplest β-diketone, acetylacetone (AcAc). With this approach, the particle size of the resultant AuNPs was tunable by simply adjusting the light intensity or AcAc dosage. Moreover, owing to the capping role of AcAc, the resultant AuNPs could be stably dispersed in water for a year without obvious change in morphology and photochemical property. Formation of ligand to metal charge transfer complexes was found to play an important role in the redox conversion of Au with AcAc. Meanwhile, the moderate complexation ability enables the surface AcAc on the AuNPs to undergo ligand exchange reactions (LER). With the aid of Ag+, the AuNPs underwent LER with glutathione and exhibited enhanced photoluminescence (PL) with a maximum of 22-fold increase in PL intensity. The PL response was linear to the concentration of glutathione in the range of 0–500 μM. Such a LER makes the obtained AuNPs being good imaging probes. To the best of our knowledge, this is the first work on illustrating the roles of AcAc as a multifunctional ligand in fabrication of NPs, which sheds new light on the surface modulation in synthesis of nanomaterials.
One-step combustion synthesis of undoped c-ZrO2 for Cr(VI) removal from aqueous solutions
Authors: Dzhevaga E V , Chebanenko M I , Martinson K D , Lobinsky A A , Popkov V I
Published: November 2021

The active practical application of materials based on cubic zirconium dioxide (c-ZrO2) for catalysis, luminescence, and sorption of heavy metals demands the development of methods for its preparation in a nanostructured form. In this work, nanoparticles of undoped cubic zirconia were obtained by solution combustion method, the features of their structure and morphology were investigated, and the efficiency of their use as a basis for sorbents for the removal of hexavalent chromium Cr(VI) from aqueous solutions was evaluated. Based on XPS, it was established that the stabilization of the high-temperature cubic phase of c-ZrO2 occurred due to oxygen vacancies which were formed during the synthesis by glycine-nitrate combustion. From the results of PXRD and Raman spectroscopy cubic structure of the obtained zirconium dioxide nanoparticles is concluded, the average crystallite size was approximately 2 nm. Adsorption structural analysis and SEM indicated aggregation of c-ZrO2 nanocrystals into primary (45–95 nm) and secondary (submicron) agglomerates. The specific surface of the nanopowder determined by the Brunauer–Emmet–Teller method was 25.4 m2 g−1, the pore volume was 0.1670 cm3 g−1, the major part of which is associated with interparticle porosity. Using kinetic pH-metry, it was found that on the surface of synthesized c-ZrO2, rapidly hydrated aprotic Lewis acid centers predominated, and the point of zero charge was 5.8. The results of the sorption of Cr(VI) from aqueous solutions with a concentration of 48–242 mg l−1 at 25 °C and pH = 5 are described by the Freundlich isotherm (R
2 = 0.971), which corresponds to multilayer adsorption. The maximum adsorption capacity according to Langmuir was 33 mg g−1 or 1.34 mg m−2 per unit area. These results allow us to consider the obtained undoped zirconium dioxide as a promising base for sorbents of heavy metals.
Invariant probabilities for discrete time linear dynamics via thermodynamic formalism
*
Authors: Lopes Artur O , Messaoudi Ali , Stadlbauer Manuel , Vargas Victor
Published: November 2021

We show the existence of invariant ergodic σ-additive probability measures with full support on X for a class of linear operators L : X → X, where L is a weighted shift operator and X either is the Banach space

c

0

(

R

)

or

l

p

(

R

)

for 1 ⩽ p < ∞. In order to do so, we adapt ideas from thermodynamic formalism as follows. For a given bounded Hölder continuous potential

A
:
X
→
R

, we define a transfer operator

L

A

which acts on continuous functions on X and prove that this operator satisfies a Ruelle–Perron–Frobenius theorem. That is, we show the existence of an eigenfunction for

L

A

which provides us with a normalised potential

A

¯

and an action of the dual operator

L

A

¯

*

on the one-Wasserstein space of probabilities on X with a unique fixed point, to which we refer to as Gibbs probability. It is worth noting that the definition of

L

A

requires an a priori probability on the kernel of L. These results are extended to a wide class of operators with a non-trivial kernel defined on separable Banach spaces.
Experiments on intense ion beam formation with an inhomogeneous electric field
Authors: Vybin S S , Skalyga V A , Izotov I V , Golubev S V , Razin S V , Shaposhnikov R A , Kazakov M Yu , Bokhanov A F , Shlepnev S P
Published: November 2021

The high efficiency of a new ion beam extraction system with a strongly inhomogeneous electric field has been experimentally demonstrated. Previously, this approach was proposed and analysed numerically by the authors. The experiment was carried out using a pulsed high-current electron-cyclotron resonance (ECR) ion source SMIS 37 with high frequency (37.5 GHz) and high power (100 kW) microwave plasma heating. The accelerating field strength is increased (when compared to a flat or a quasi-pierced geometry) in the plasma meniscus region due to its inhomogeneity. It allows for the increase of the ion acceleration rate and for expansion of the available range of current densities with effective ion beam formation. The experiment demonstrated the main advantages of this approach, such as: a significant decrease in the optimal accelerating voltage for certain values of current density; a possibility of ion beam formation with previously inaccessible current densities; a significant decrease in the ion flux to the puller in non-optimal modes of ion beam formation. Proton beams with a current density of up to 1.1 A cm−2 were obtained for the first time with an ECR ion source.
Enhancement-mode normally-off β-Ga2O3:Si metal-semiconductor field-effect deep-ultraviolet phototransistor
Authors: Liu Zeng , Zhang Maolin , Yang Lili , Li Shan , Zhang Shaohui , Li Kaikai , Li Peigang , Guo Yufeng , Tang Weihua
Published: November 2021

In this work, a solar-blind ultraviolet (UV) photodetector based on a three-terminal enhancement-mode (E-mode) Si-doped β-Ga2O3 (β-Ga2O3:Si) metal-semiconductor field-effect transistor structure is demonstrated, whose threshold voltage (V
th) and subthreshold swing are 4.04 V and 1.4 V dec−1, respectively. A 400 nm thick β-Ga2O3:Si thin film is prepared on sapphire substrate by using metal-organic chemical vapor deposition method. Controlling the channel currents by the Schottky gate voltage in the dark and under illuminations, the photodetector shows dark current (I
dark) as low as 13.4 pA, photo-to-dark current ratio of 4.85 × 104 and linear dynamic range of 29.6 dB, illuminated by 254 nm UV light of 245 μW cm−2. As the UV light is turned on and off, the output current rise and decay time (τ
r and τ
d) are 420 ms and 350 ms. Moreover, at drain voltage (V
ds) of 5 V and gate voltage (V
gs) of 0 V, the responsivity (R), specific detectivity (D*) and external quantum efficiency are achieved as 74 A W−1, 2.15

×

1014 cm Hz1/2 W−1 (Jones) and 3.6

×

104%, respectively.
Design and experimental evaluation a novel magneto-rheological brake with tooth shaped rotor
Authors: Nguyen Van Bien , Le Hiep Dai , Nguyen Quoc Hung , Duyen Do Qui , Hieu Do Huu Minh , Choi Seung-bok
Published: November 2021

In this study, a novel magnetorheological brake (MRB) with tooth-shape rotor is developed. In this new MRB, traditional cylindrical rotor is replaced by a new one with tooth-shaped rotor. The teeth on the rotor act as multiple magnetic poles of the brake. Two magnetic coils are placed on side-housings of the brake to generate a mutual magnetic field of the MRB. The inner face of each side-housing has tooth shaped features as well. These tooth shaped features interact with the rotor teeth via magnetorheological fluid (MRF) medium. By using the tooth shaped rotor, more interface area between the rotor and the working MRF can be archived, which can improve performance characteristics of the proposed MRB such as compact size, low power consumption and high braking torque. After an introduction of state of the art of MRB development, the schematics and working principle of the MRB with tooth-shaped rotor is proposed. The modeling of the MRB is then derived based on magnetic finite element analysis and Bingham rheological model of MRF. Optimal design of the MRB considering mass and braking torque of the MRB is then conducted. From the optimal design result, it is shown that the mass and power consumption of the proposed MRB are significantly smaller than those of previously developed ones. In details, at high value of the maximum braking torque (100 Nm), the proposed MRB mass is only around 31.3% of the mass of the thin-wall single-coil and 42.6% of the mass of the thin-wall double coil MRB. In addition, at small values of the maximum braking torque (5 Nm), power consumption of the proposed MRB is only around 33% of that of the thin-wall single-coil and 45.5% of that of the thin-wall double coil MRB. Experimental works on prototypes of the proposed MRB are then performed for validation.
Boundary layer state detection using piezoelectric sensors
Authors: Stuber Vincent L , Kotsonis Marios , van der Zwaag Sybrand
Published: November 2021

Two piezoelectric series bimorph sensors were embedded below the skin of a NACA 0012 symmetrical airfoil to detect the local state of the boundary layer during wind tunnel testing. Small vanes piercing the airfoil skin were glued onto the bimorphs providing a mechanical coupling to the local mechanical force fluctuations imparted by the local unsteady boundary layer flow. The state of the boundary layer at the sensor sites was varied by changing the angle of attack. The objective of this work was to establish the ability of this sensor concept to accurately distinguish among typical boundary layer states such as attached laminar flow, turbulent flow and separated flow. The output of the sensor was compared to concurrent time-resolved particle image velocimetry measurements, which served as a validation technique. Using the developed sensor response envelope, a single data point time series of the piezo electrical signal was proven to be sufficient to accurately detect the boundary layer state on classical airfoils in the low Reynolds number regime. In projected future applications, single or arrays of bimorph sensors can be used to map the boundary layer of more complex or morphing shape airfoils. The fast response of the sensor can in principle be utilised in closed-loop flow control systems, aimed at drag reduction or lift enhancement.
Non-Hermitian bulk-boundary correspondence and singular behaviors of generalized Brillouin zone
Authors: Guo Gang-Feng , Bao Xi-Xi , Tan Lei
Published: November 2021

The bulk boundary correspondence, which connects the topological invariant, the continuum band and energies under different boundary conditions, is the core concept in the non-Bloch band theory, in which the generalized Brillouin zone (GBZ), appearing as a closed loop generally, is a fundamental tool to rebuild it. In this work, it can be shown that the recovery of the open boundary energy spectrum by the continuum band remains unchanged even if the GBZ itself shrinks into a point. Contrastively, if the bizarreness of the GBZ occurs, the winding number will become illness. Namely, we find that the bulk boundary correspondence can still be established whereas the GBZ has singularities from the perspective of the energy, but not from the topological invariant. Meanwhile, regardless of the fact that the GBZ comes out with the closed loop, the bulk boundary correspondence cannot be well characterized yet because of the ill-definition of the topological number. Here, the results obtained may be useful for improving the existing non-Bloch band theory.
Generalized Darboux transformation and asymptotic analysis on the degenerate dark-bright solitons for a coupled nonlinear Schrödinger system
Authors: Tian He-Yuan , Tian Bo , Sun Yan , Chen Su-Su
Published: November 2021

In this paper, our work is based on a coupled nonlinear Schrödinger system in a two-mode nonlinear fiber. A (N,m)-generalized Darboux transformation is constructed to derive the Nth-order solutions, where the positive integers N and m denote the numbers of iterative times and of distinct spectral parameters, respectively. Based on the Nth-order solutions and the given steps to perform the asymptotic analysis, it is found that a degenerate dark-bright soliton is the nonlinear superposition of several asymptotic dark-bright solitons possessing the same profile. For those asymptotic dark-bright solitons, their velocities are z-dependent except that one of those velocities could become z-independent under certain condition, where z denotes the evolution dimension. Those asymptotic dark-bright solitons are reflected during the interaction. When a degenerate dark-bright soliton interacts with a nondegenerate/degenerate dark-bright soliton, the interaction is elastic, and the asymptotic bound-state dark-bright soliton with z-dependent or z-independent velocity could take place under certain condition. Our study extends the investigation on the degenerate solitons from the bright soliton case for the scalar equations to the dark-bright soliton case for a coupled system.
High power λ ~ 8.5 μm quantum cascade laser grown by MOCVD operating continuous-wave up to 408 K
Authors: Fei Teng , Zhai Shenqiang , Zhang Jinchuan , Zhuo Ning , Liu Junqi , Wang Lijun , Liu Shuman , Jia Zhiwei , Li Kun , Sun Yongqiang , Guo Kai , Liu Fengqi , Wang Zhanguo
Published: November 2021

Robust quantum cascade laser (QCL) enduring high temperature continuous-wave (CW) operation is of critical importance for some applications. We report on the realization of lattice-matched InGaAs/InAlAs/InP QCL materials grown by metal-organic chemical vapor deposition (MOCVD). High interface quality structures designed for light emission at 8.5 μm are achieved by optimizing and precise controlling of growth conditions. A CW output power of 1.04 W at 288 K was obtained from a 4 mm-long and 10 μm-wide coated laser. Corresponding maximum wall-plug efficiency and threshold current density were 7.1% and 1.18 kA/cm2, respectively. The device can operate in CW mode up to 408 K with an output power of 160 mW.
Energy deposition and melt deformation on the ITER first wall due to disruptions and vertical displacement events
Authors: Coburn J. , Lehnen M. , Pitts R.A. , Simic G. , Artola F.J. , Thorén E. , Ratynskaia S. , Ibano K. , Brank M. , Kos L. , Khayrutdinov R. , Lukash V.E. , Stein-Lubrano B. , Matveeva E. , Pautasso G.
Published: November 2021

An analysis workflow has been developed to assess energy deposition and material damage for ITER vertical displacement events (VDEs) and major disruptions (MD). This paper describes the use of this workflow to assess the melt damage to be expected during unmitigated current quench (CQ) phases of VDEs and MDs at different points in the ITER research plan. The plasma scenarios are modeled using the DINA code with variations in plasma current I
p, disruption direction (upwards or downwards), Be impurity density n
Be, and diffusion coefficient χ. Magnetic field line tracing using SMITER calculates time-dependent, 3D maps of surface power density q
⊥ on the Be-armored first wall panels (FWPs) throughout the CQ. MEMOS-U determines the temperature response, macroscopic melt motion, and final surface topology of each FWP. Effects of Be vapor shielding are included. Scenarios at the baseline combination of I
p and toroidal field (15 MA/5.3 T) show the most extreme melt damage, with the assumed n
Be having a strong impact on the disruption duration, peak q
⊥ and total energy deposition to the first wall. The worst-cases are upward 15 MA VDEs and MDs at lower values of n
Be, with q
⊥,max = 307 MW m−2 and maximum erosion losses of ∼2 mm after timespans of ∼400–500 ms. All scenarios at 5 MA avoided melt damage, and only one 7.5 MA scenario yields a notable erosion depth of 0.25 mm. These results imply that disruptions during 5 MA, and some 7.5 MA, operating scenarios will be acceptable during the pre-fusion power operation phases of ITER. Preliminary analysis shows that localized melt damage for the worst-case disruption should have a limited impact on subsequent stationary power handling capability.
A new and improved IceCube point source analysis
Authors: Bellenghi C. , Glauch T. , Haack C. , Kontrimas T. , Niederhausen H. , Reimann R. , Wolf M.
Published: November 2021

The IceCube Neutrino Observatory, a cubic kilometer scale Cherenkov detector deployed in the deep ice at the geographic South Pole, investigates extreme astrophysical phenomena by studying the corresponding high-energy neutrino signal. Its discovery of a diffuse flux of astrophysical neutrinos with energies up to the PeV scale in 2013 has triggered a vast effort to identify the mostly unknown sources of these high energy neutrinos. Here, we present a new IceCube point-source search that improves the accuracy of the statistical analysis, especially at energies of a few TeV and below. The new approach is based on multidimensional kernel density estimation for the probability density functions and new estimators for the observables, namely the reconstructed energy and the estimated angular uncertainty on the reconstructed arrival direction. The more accurate analysis provides an improvement in discovery potential up to ∼30% over previous works for hard spectrum sources.
Four-electrode probe for plasma studies in the GOL-NB multiple-mirror trap
Authors: Sidorov E.N. , Batkin V.I. , Burdakov A.V. , Ivanov I.A. , Kuklin K.N. , Mekler K.I. , Nikishin A.V. , Postupaev V.V. , Rovenskikh A.F.
Published: November 2021

A system of four-electrode Langmuir probes developed for the GOL-NB multiple-mirror trap is discussed. The system is used for studies of a low-temperature start plasma (1019–1020 m-3, 5 eV) that fills the device during the initial phase of the experiment. The probe allows simultaneous measurements of plasma density, electron temperature and radial electric field. The accuracy of the probe measurements is also discussed.
Decreasing methane emissions from China’s coal mining with rebounded coal production
Authors: Gao Junlian , Guan Chenghe , Zhang Bo , Li Ke
Published: November 2021

China is the world’s largest anthropogenic methane (CH4) emitter, with coal mine methane (CMM) as one of the main contributors. However, previous studies have not reach consensus on the magnitude and trend of China’s CMM emissions since 2010. Through distribution fitting and Monte Carlo methods, dynamic emission factors (EFs) of CMM at the province-level were derived with high confidence; along with the updated data on surface mining, abandoned coal mines, and methane utilization, we revealed that China’s annual CMM emissions were estimated at 20.11 Tg between 2010 and 2019 with a decline of 0.93 Tg yr−1. Although coal production was revived in 2017, we found that the growing trend of China’s CMM emissions since 2012 were curbed by the previously-overlooked factors including the growth of CMM utilization and coal production from surface mining, and decrease of EFs driven by the closure of high CH4-content coal mines and a regional production shift to lower-emission areas.
On steady motions of an ideal fibre-reinforced fluid in a curved stratum. Geometry and integrability
Authors: Demskoi Dmitry K , Schief Wolfgang K
Published: November 2021

It is shown that the kinematic equations governing steady motions of an ideal fibre-reinforced fluid in a curved stratum may be expressed entirely in terms of the intrinsic Gauss equation, which assumes the form of a partial differential equation of third order, for the surface representing the stratum. In particular, the approach adopted here leads to natural non-classical orthogonal coordinate systems on surfaces of constant Gaussian curvature with one family of coordinate lines representing the fibres. Integrable cases are isolated by requiring that the Gauss equation be compatible with another third-order hyperbolic differential equation. In particular, a variant of the integrable Tzitzéica equation is derived which encodes orthogonal coordinate systems on pseudospherical surfaces. This third-order equation is related to the Tzitzéica equation by an analogue of the Miura transformation for the (modified) Korteweg–de Vries equation. Finally, the formalism developed in this paper is illustrated by focussing on the simplest ‘fluid sheets’ of constant Gaussian curvature, namely the plane, sphere and pseudosphere.
A transport equation approach for deep neural networks with quenched random weights
Authors: Agliari E , Albanese L , Alemanno F , Fachechi A
Published: November 2021

We consider a multi-layer Sherrington–Kirkpatrick spin-glass as a model for deep restricted Boltzmann machines with quenched random weights and solve for its free energy in the thermodynamic limit by means of Guerra’s interpolating techniques under the RS and 1RSB ansatz. In particular, we recover the expression already known for the replica-symmetric case. Further, we drop the restriction constraint by introducing intra-layer connections among spins and we show that the resulting system can be mapped into a modular Hopfield network, which is also addressed via the same techniques up to the first step of replica symmetry breaking.
A multi-channeled vortex beam switch with moiré metasurfaces
Authors: Cui Cheng , Liu Zheng , Hu Bin , Jiang Yurong , Liu Juan
Published: November 2021

Tunable metasurface devices are considered to be an important link for metasurfaces to practical applications due to their functional diversity and high adaptability to application scenarios. Metasurfaces have unique value in the generation of vortex beams because they can realize light wavefronts of any shape. In recent years, several vortex beam generators using metasurfaces have been proposed. However, topological charge generally lacks tunability, which reduces the scope of their applications. Here, we propose an active tunable multi-channeled vortex beam switch based on a moiré structure composed of two cascaded dielectric metasurfaces. The simulation results show that when linearly polarized light with a wavelength of 810 nm is incident, the topological charge from −6 to +6 can be continuously generated by relatively rotating the two metasurfaces. Meanwhile, different topological charges are deflected to different spatial channels, realizing the function of multi-channeled signal transmission. We also study the efficiency and broadband performance of the structure. The proposed multi-channel separation method involving vortex beams that can actively tune topological charges paves the way for the compactness and functional diversity of devices in the fields of optical communications, biomedicine, and optoelectronics.
Efficiency of the novel TP/LLDPE nanocomposite in killing multi-drug resistant pathogens
Authors: Mohamad Faudzi Ku Nur Izzati Ku , Sreekantan Srimala , Mydin Rabiatul Basria S M N , Basiron Norfatehah , Hassan Mohd , Nabi Arshid
Published: November 2021

A series of linear low-density polyethylene (LLDPE) polymer nanocomposites with g-C3N4-ZnO/TiO2 ternary photocatalyst (TP) at 1 wt%, 5 wt%,7 wt%, and 10 wt% was synthesised by melt blending method. The structural properties, chemical properties, photocatalytic and antibacterial activities were evaluated in this study. The addition of TP reduces the degree of crystallisation of the LLDPE nanocomposite. The OH functional group on TP increases the polarity, thus improving the LB broth’s wettability for bacterial adhesion, which enhances the inactivation effect. A minimum of 0.3 mg l−1 of Zn2+ together with ·OH and ·

O

2

−

are required to inactivate the MDR pathogens. More than 99% inactivation in 6 h can be achieved against MDR pathogens for 5 wt% TP loading while 12 h for 1 wt% TP loading in LLDPE nanocomposites. The photocatalytic performance of the zinc oxide and titanium oxide for the degradation of methylene blue has exhibited good photocatalytic properties. The obtained results have confirmed the photocatalytic activity for the bactericidal effect of TP/LLDPE composites was dominant by ·OH and ·

O

2

−

while slightly by holes. The purpose of this work is to obtain the optimum amount of ternary photocatalyst incorporated with LLDPE and incubation time required to kill a broad spectrum of multidrug-resistant (MDR) pathogens like E. coli, S. aureus, B. subtilis, S. flexneri, B. cereus, and K. pneumoniae. The LLDPE nanocomposite with 1 wt% showed >99% inactivation against the MDR pathogens within 12 h while with 5 wt%, it takes 6 h. The synergic action of structural properties such as crystallinity, wettability, chemical structure on the reactive oxygen species (ROS), and Zn ion release for inactivation against the MDR pathogens is deliberated.
Quantum dot-like plasmonic modes in twisted bilayer graphene supercells
Authors: Westerhout Tom , Katsnelson Mikhail I , Rösner Malte
Published: November 2021

We derive a material-realistic real-space many-body Hamiltonian for twisted bilayer graphene from first principles, including both single-particle hopping terms for p

z
electrons and their long-range Coulomb interaction. By disentangling low- and high-energy subspaces of the electronic dispersion, we are able to utilize state-of-the-art constrained random phase approximation calculations to reliably describe the non-local background screening from the high-energy s, p

x
, and p

y
electron states which we find to be independent of the bilayer stacking and thus of the twisting angle. The twist-dependent low-energy screening from p

z
states is subsequently added to obtain a full screening model. We use this modeling scheme to study plasmons in electron-doped twisted bilayer graphene supercells. We find that the finite system size yields discretized plasmonic levels, which are controlled by the system size, doping level, and twisting angle. This tunability together with atomic-like charge distributions of some of the excitations renders these plasmonic excitations remarkably similar to the electronic states in electronic quantum dots. To emphasize this analogy in the following we refer to these supercells as plasmonic quantum dots. Based on a careful comparison to pristine AB-stacked bilayer graphene plasmons, we show that two kinds of plasmonic excitations arise, which differ in their layer polarization. Depending on this layer polarization the resulting plasmonic quantum dot states are either significantly or barely dependent on the twisting angle. Due to their tunability and their coupling to light, these plasmonic quantum dots form a versatile and promising platform for tailored light-matter interactions.
A novel antibacterial and biocompatible wound cover made of gelatin/chitosan with silver nanoparticles of green synthesis
Authors: Dotto Dayane , Scatolini Márcio , Pugini Silvana , Vercik Luci , Melo Mariza , Vercik Andrés , Rigo Eliana
Published: November 2021

A dressing material based on the combination of gelatine, chitosan and silver nanoparticles with a suitable proportion has been developed and can be successfully applied in biomedical fields. The new gelatin/chitosan membranes were prepared using the chitosan suspension mixed with gelatin and silver nanoparticles (AgNPs), resulting in a biocompatible and antibacterial product. AgNPs were obtained by the reduction of silver nitrate with chitosan solution and added to chitosan/gelatin (GCs) blend solutions to obtain membranes by the casting method. Thus, membranes with three different AgNPs concentrations were produced: 30 mM, 20 mM and 10 mM AgNPs. To evaluate the characteristics of the membranes, physicochemical and morphological tests were carried out, such as infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission (TEM), and in vitro cytotoxicity and bacterial assays. The formation of AgNPs was confirmed by Visible Ultraviolet to Ultraviolet to Visible (UV–vis) and TEM, where the nanoparticles were observed by the formation of the peak spectrum at a wavelength at 560 nm. According to the TEM images, polymorphic nanoparticles with an average size of 30 nm were obtained. Furthermore, the results of scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) indicated the presence of silver evenly distributed within the membranes. The results obtained by (FTIR) showed spectral peaks characteristic of the membrane materials, that is, typical spectra of gelatin, chitosan and silver. These results could be explained by addition of free −OH, −NH2 and −NHOCOCH3 groups of the amorphous chitosan in the blends and a network structure through electrostatic interactions between the ammonium ions (−NH3+) of the chitosan and the carboxylate ions (−COO−) of the gelatin. The concentrations of AgNPs 30 mM and 20 mM in the membranes attributed to them a high hydration rate and high water vapor permeability (WVP). Membranes with 30 mM AgNPs showed bacterial effect against Staphylococcus aureus and Pseudomonas aeruginosa, concentrations of 20 mM AgNPs and 10 mM AgNPs, bacteriostatic effect against Staphylococcus aureus and bacterial effect against Pseudomonas aeruginosa. In the results of the in vitro assays, 10 mM AgNPs membranes were not cytotoxic. With the results obtained, GC membranes with up to 10 mM AgNPs are candidates for use in the fields of biomaterials and biomedicine.
Numerical simulation of low-current vacuum arc jet considering anode evaporation in different axial magnetic fields
Authors: ZHANG Zhefeng , WANG Lijun , YANG Ze , LUO Ming , LI Jiagang
Published: November 2021

As the main source of the vacuum arc plasma, cathode spots (CSs) play an important role on the behaviors of the vacuum arc. Their characteristics are affected by many factors, especially by the magnetic field. In this paper, the characteristics of the plasma jet from a single CS in vacuum arc under external axial magnetic field (AMF) are studied. A multi-species magneto-hydro-dynamic (MHD) model is established to describe the vacuum arc. The anode temperature is calculated by the anode activity model based on the energy flux obtained from the MHD model. The simulation results indicate that the external AMF has a significant effect on the characteristic of the plasma jet. When the external AMF is high enough, a bright spot appears on the anode surface. This is because with a higher AMF, the contraction of the diffused arc becomes more obvious, leading to a higher energy flux to the anode and thus a higher anode temperature. Then more secondary plasma can be generated near the anode, and the brightness of the ‘anode spot’ increases. During this process, the arc appearance gradually changes from a cone to a dumbbell shape. In this condition, the arc is in the diffuse mode. The appearance of the plasma jet calculated in the model is consistent with the experimental results.
Modulation of the thermal transport of micro-structured materials from 3D printing
Authors: Sun Qiangsheng , Xue Zhixiang , Chen Yang , Xia Ruding , Wang Jianmei , Xu Shen , Zhang Jun , Yue Yanan
Published: November 2021

It is desirable to fabricate materials with adjustable physical properties that can be used in different industrial applications. Since the property of a material is highly dependent on its inner structure, the understanding of structure–property correlation is critical to the design of engineering materials. 3D printing appears as a mature method to effectively produce micro-structured materials. In this work, we created different stainless-steel microstructures by adjusting the speed of 3D printing and studied the relationship between thermal property and printing speed. Our microstructure study demonstrates that highly porous structures appear at higher speeds, and there is a nearly linear relationship between porosity and printing speed. The thermal conductivity of samples fabricated by different printing speeds is characterized. Then, the correlation between porosity, thermal conductivity, and scanning speed is established. Based on this correlation, the thermal conductivity of a sample can be predicted from its printing speed. We fabricated a new sample at a different speed, and the thermal conductivity measurement agrees well with the value predicted from the correlation. To explore thermal transport physics, the effects of pore structure and temperature on the thermal performance of the printed block are also studied. Our work demonstrates that the combination of the 3D printing technique and the printing speed control can regulate the thermophysical properties of materials.
Causal Knowledge as a Prerequisite for Interrogating Bias: Reflections on Hernán et al. 20 Years Later
Authors: Levy Natalie S , Keyes Katherine M
Published: November 2021

In their seminal 2002 paper, “Causal Knowledge as a Prerequisite for Confounding Evaluation: An Application to Birth Defects Epidemiology,” Hernán et al. (Am J Epidemiol. 2002;155(2):176–184) emphasized the importance of using theory rather than data to guide confounding control, focusing on colliders as variables that share characteristics with confounders but whose control may actually introduce bias into analyses. In this commentary, we propose that the importance of this paper stems from the connection the authors made between nonexchangeability as the ultimate source of bias and structural representations of bias using directed acyclic graphs. This provided both a unified approach to conceptualizing bias and a means of distinguishing between different sources of bias, particularly confounding and selection bias. Drawing on examples from the paper, we also highlight unresolved questions about the relationship between collider bias, selection bias, and generalizability and argue that causal knowledge is a prerequisite not only for identifying confounders but also for developing any hypothesis about potential sources of bias.
Risk of Cancer in Paediatric onset Inflammatory Bowel Diseases: A Nation-wide Study From the epi-IIRN
Authors: Atia Ohad , Harel Sasha , Ledderman Natan , Greenfeld Shira , Kariv Revital , Dotan Iris , Balicer Ran , Silverman Barbara , Matz Eran , Levi Zohar , Waterman Matti , Fried Iris , Rowe Jacob M , Turner Dan
Published: November 2021

Background

Paediatric onset IBD [PIBD] is characterised by a more extensive phenotype than adult-onset IBD and a higher utilisation of immunosuppressive medications; both may be associated with malignancy. We aimed to assess the risk of cancer in a nationwide cohort of PIBD and to explore the risks associated with medical treatments.

Methods

PIBD patients [<18 years old] were included from the epi-IIRN cohort, covering 98% of the Israeli population from 2005, linked to the national cancer registry. We matched PIBD children to non-IBD children for calculating the cumulative incidence of cancer.

Results

In all, 3944 PIBD cases were included (2642 [67%] Crohn’s disease, 1302 [33%] ulcerative colitis) translating into 23 635 person-years of follow-up, individually matched to 13 005 non-IBD children. By 30 years of age, 14 IBD patients [0.35%, 5.9/10 000 patient-years] were diagnosed with cancer and one [0.03%] with haemophagocytic-lymphohistiocytosis [HLH], compared with 14 [0.11%, 1.9/10 000 patient-years] cases of cancer {relative risk (RR) 2.5 (95% confidence interval [CI] 1.05-6.2); p = 0.04} and no HLH in the comparison-group. There were no cases of hepatosplenic T cell lymphoma, adenocarcinoma, or cholangiocarcinoma. Cancer risk was 15.6 cases/10 000 person-years in those treated with thiopurines alone (RR compared with IBD patients never exposed to either thiopurines or anti-tumuor necrosis factor [TNF] 1.8 [95% CI 0.6-6.1]; p = 0.2), 11.1/10 000 in those treated with anti-TNF alone (RR 1.3 [95% CI 0.3-6.6]; p = 0.5), and 23.1/10 000 treated with combination therapy of anti-TNF and thiopurines (RR 2.8 [95% CI 0.6-13.8]; p = 0.2).

Conclusions

PIBD confers an increased risk for malignancy compared with non-IBD in children. However, the absolute risk is very low and no differences in risk with specific therapies were apparent in our data.
The resistance of the wheat microbial community to water stress is more influenced by plant compartment than reduced water availability
Authors: Agoussar Asmaâ , Azarbad Hamed , Tremblay Julien , Yergeau Étienne
Published: November 2021

Drought is a serious menace to agriculture across the world. However, it is still not clear how this will affect crop-associated microbial communities. Here, we experimentally manipulated precipitation in the field for two years and compared the bacterial communities associated with leaves, roots, and rhizosphere soils of two different wheat genotypes. The bacterial 16S rRNA gene was amplified and sequenced, while 542 microorganisms were isolated and screened for their tolerance to osmotic stress. The bacterial community was not significantly affected by the precipitation manipulation treatments but differed drastically from one plant compartment to the other. Forty-four isolates, mostly bacteria, showed high levels of resistance to osmotic stress by growing in liquid medium supplemented with 30% polyethylene glycol. The Actinobacteria were overrepresented among these isolates, and in contrast to our expectation, precipitation treatments did not influence the odds of isolating osmotic stress-resistant bacteria. However, the odds were significantly higher in the leaves as compared to the roots, the rhizosphere, or the seeds. Our results suggest that isolation efforts for wheat-compatible water stress resistant bacteria should be targeted at the leaf endosphere and that short-term experimental manipulation of precipitation does not result in a more resistant community.
Friendship and Cognitive Functioning Among Married and Widowed Chinese Older Adults
Authors: Peng Changmin , Hayman Laura L , Mutchler Jan E , Burr Jeffrey A
Published: November 2021

Objectives

Guided by the social convoy model, this study investigated the association between friendship and cognitive functioning among older Chinese adults, as well as the moderating effect of marital status (married vs widowed). We also explored whether depression might account for the link between friendship and cognitive functioning.

Methods

We used data from the China Longitudinal Aging Social Survey in 2014 (N = 8,482). Cognitive functioning was measured with the Mini-Mental State Examination instrument and friendship was assessed with a 3-item Lubben Social Network Scale. Linear regression and path analyses within a structural equation modeling framework were performed to examine the hypotheses.

Results

Results indicated that friendship was significantly related to better cognitive functioning among older Chinese adults (β = 0.083, p < .001) and marital status moderated this association (β = −0.058, p < .01). In addition, depression partially mediated the relationship between friendship and cognitive functioning (β = 0.015, p < .001).

Discussion

The results implied that friendship is important for maintaining cognitive functioning in later life and widowed older Chinese adults may benefit more from friendship in its relationship to cognitive functioning than married older Chinese adults. Further, one potential pathway linking friendship to cognitive functioning may be through depression; however, more research is needed to support this finding. Intervention programs aimed at building friendship opportunities may be one way to achieve better cognitive aging.
Integrating health technology assessment and the right to health: a qualitative content analysis of procedural values in South African judicial decisions
Authors: DiStefano Michael J , Abdool Karim Safura , Krubiner Carleigh B
Published: November 2021

South Africa’s move towards implementing National Health Insurance includes a commitment to establish a health technology assessment (HTA) body to inform health priority-setting decisions. This study sought to analyse health rights cases in South Africa to inform the identification of country-specific procedural values related to health priority-setting and their implementation in a South African HTA body. The focus on health rights cases is motivated in part by the fact that case law can be an important source of insight into the values of a particular country. This focus is further motivated by a desire to mitigate the potential tension between a rights-based approach to healthcare access and national efforts to set health priorities. A qualitative content analysis of eight South African court cases related to the right to health was conducted. Cases were identified through a LexisNexis search and supplemented with expert judgement. Procedural values identified from the health priority-setting literature, including those comprising Accountability for Reasonableness (A4R), structured the thematic analysis. The importance of transparency and revision—two elements of A4R—is evident in our findings, suggesting that the courts can help to enforce elements of A4R. Yet our findings also indicate that A4R is likely to be insufficient for ensuring that HTA in South Africa meets the procedural demands of a constitutional rights-based approach to healthcare access. Accordingly, we also suggest that a South African HTA body ought to consider more demanding considerations related to transparency and revisions as well as explicit considerations related to inclusivity.
Investigation of the causal relationships between human IgG N-glycosylation and 12 common diseases associated with changes in the IgG N-glycome
Authors: Zaytseva Olga O , Sharapov Sodbo Zh , Perola Marcus , Esko Tonu , Landini Arianna , Hayward Caroline , Wilson James F , Lauc Gordan , Aulchenko Yurii S , Klarić Lucija , Tsepilov Yakov A
Published: November 2021

Changes in the N-glycosylation of immunoglobulin G (IgG) are often observed in pathological states, such as autoimmune, inflammatory, neurodegenerative, cardiovascular diseases and some types of cancer. However, in most cases, it is not clear if the disease onset causes these changes, or if the changes in IgG N-glycosylation are among the risk factors for the diseases. The aim of this study was to investigate the casual relationships between IgG N-glycosylation traits and 12 diseases, in which the alterations of IgG N-glycome were previously reported, using two sample Mendelian randomization (MR) approach. We have performed two sample MR using publicly available summary statistics of genome-wide association studies of IgG N-glycosylation and disease risks. Our results indicate positive causal effect of systemic lupus erythematosus (SLE) on the abundance of N-glycans with bisecting N-acetylglucosamine in the total IgG N-glycome. Therefore, we suggest regarding this IgG glycosylation trait as a biomarker of SLE. We also emphasize the need for more powerful GWAS studies of IgG N-glycosylation to further elucidate the causal effect of IgG N-glycome on the diseases.
Fecal Amino Acid Analysis in Newly Diagnosed Pediatric Inflammatory Bowel Disease: A Multicenter Case-Control Study
Authors: Jagt Jasmijn Z , Struys Eduard A , Ayada Ibrahim , Bakkali Abdellatif , Jansen Erwin E W , Claesen Jürgen , van Limbergen Johan E , Benninga Marc A , de Boer Nanne K H , de Meij Tim G J
Published: November 2021

Background

Fecal metabolomic profiles differ between pediatric inflammatory bowel disease (IBD) patients and controls and may provide new insights in the pathophysiology of IBD. The role of amino acids, however, is not fully elucidated. We aimed to assess fecal amino acid profiles in pediatric IBD.

Methods

In this case-control study, treatment-naïve, newly diagnosed pediatric IBD patients and a non-IBD control group, matched based on sex and age, were included in 2 tertiary centres. Fecal amino acid profiles were assessed using a targeted high-performance liquid chromatography technique. A random forest classifier method was used to develop a prediction model differentiating IBD from controls and predicting IBD phenotype. The association between IBD localization and amino acid concentrations was tested with ordinal regression models.

Results

We included 78 newly diagnosed IBD patients (40 Crohn’s disease [CD], 38 ulcerative colitis [UC]) and 105 controls. Patients with IBD could be differentiated from controls with an accuracy of 82% (sensitivity 63%, specificity 97%). Twenty-nine out of the 42 measured unique amino acids were included in the prediction model. Increased levels of tryptophan, taurine, alanine, ornithine, valine, histidine, and leucine were the most differentiating features. Children with CD and UC could be differentiated from the controls with an accuracy of 80% and 90%, respectively. Inflammatory bowel disease phenotype could not be predicted. Tryptophan, valine, and histidine levels were positively associated with more extended disease in UC patients (P < .05).

Conclusions

Fecal amino acids may enhance understanding of the role of host-microbial interactions in the pathophysiology of IBD and may evolve into biomarkers for pediatric IBD diagnostic and personalized medicine.
Energy management strategy of hybrid energy storage system based on fuzzy control for ships
Authors: Hu Wenqing , Shang Qianming , Bian Xiangrui , Zhu Renjie
Published: November 2021

Lithium-ion batteries have high-energy density, but they cannot respond quickly to power fluctuations; supercapacitors (SCs) can quickly respond to power fluctuations, but their energy density is low. The hybrid energy storage system (HESS) that uses both lithium-ion batteries and SCs can take into account the advantages of both, making the system perform better; however, the energy distribution between lithium-ion batteries and SC is difficult. This paper takes ships as the research object, analyzes the power changes of ships during operation, and finds that high-power fluctuations are always only a minority. This paper uses a fuzzy control strategy, based on the actual operating conditions of the ship, except that the ship’s power fluctuation is very small; the SC will provide energy for the ship to make full use of the SC instead of waiting for the arrival of high-power fluctuations. This paper builds an experimental platform and uses the Arbin tester to simulate the operation of the ship. The experimental data show that the SC can have enough time to adjust its state of charge to deal with the power fluctuations at the next moment even if it keeps charging and discharging. The research results of this paper have certain significance for the energy distribution and capacity configuration of HESS.
Geometrization of Trigonometric Solutions of the Associative and Classical Yang–Baxter Equations
Authors: Polishchuk Alexander
Published: November 2021

We describe a geometric construction of all nondegenerate trigonometric solutions of the associative and classical Yang–Baxter equations. In the associative case, the solutions come from symmetric spherical orders over the irreducible nodal curve of arithmetic genus $1$, while in the Lie case they come from spherical sheaves of Lie algebras over the same curve.
On the Thom Conjecture in ℂℙ3
Authors: Ruberman Daniel , Slapar Marko , Strle Sašo
Published: November 2021

What is the simplest smooth simply connected $4$-manifold embedded in $\mathbb {C}\mathbb {P}^3$ homologous to a degree $d$ hypersurface $V_d$? A version of this question associated with Thom asks if $V_d$ has the smallest $b_2$ among all such manifolds. While this is true for degree at most $4$, we show that for all $d \geq 5$, there is a manifold $M_d$ in this homology class with $b_2(M_d) < b_2(V_d)$. This contrasts with the Kronheimer–Mrowka solution of the Thom conjecture about surfaces in $\mathbb {C}\mathbb {P}^2$ and is similar to results of Freedman for $2n$-manifolds in $\mathbb {C}\mathbb {P}^{n+1}$ with $n$ odd and greater than $1$.