Cellulose-based aerogel derived N, B-co-doped porous biochar for high-performance CO2 capture and supercapacitor

The remarkable characteristics of porous biochar have generated significant interest in various fields, such as CO2 capture and supercapacitors. The modification of aerogel-derived porous biochar through activation and heteroatomic doping can effectively enhance CO2 adsorption and improve supercapacitor performance. In this study, a novel N, B-co-doped porous biochar (NBCPB) was synthesized by carbonating and activating the N, B dual-doped cellulose aerogel. N and B atoms were doped in-situ using a modified alkali-urea method. The potassium citrate was served as both an activator and a salt template to facilitate the formation of a well-developed nanostructure. The optimized NBCPB-650-1 (where 650 corresponded to activation temperature and 1 represented mass ratio of potassium citrate activator to carbonized NBCPB-400 precursor) displayed the largest micropore volume of 0.40 cm3·g-1 and a high specific surface area of 891 m2·g-1, which contributed to an excellent CO2 adsorption capacity of 4.19 mmol·g-1 at 100 kPa and 25 °C, a high CO2/N2 selectivity, and exceptional reusability (retained >97.5 % after 10 adsorption-desorption cycles). Additionally, the NBCPB-650-1 electrode also delivered a high capacitance of 220.9 F·g-1 at 1 A·g-1. Notably, the symmetrical NBCPB-650-1 supercapacitor exhibited a high energy density of 9 Wh·kg-1 at the power density of 100 W·kg-1. This study not only presents the potential application of NBCPB-650-1 material in CO2 capture and electrochemical energy storage, but also offers a new insight into easy-to-scale production of heteroatomic-modified porous biochar.

Generation and characterization of a nanobody against the avian influenza virus H7 subtype

Avian influenza virus (AIV) H7N9 diseases have been recently reported, raising concerns about a potential pandemic. Thus, there is an urgent need for effective therapeutics for AIV H7N9 infections. Herein, camelid immunization and yeast two-hybrid techniques were used to identify potent neutralizing nanobodies (Nbs) targeting the H7 subtype hemagglutinin. First, we evaluated the binding specificity and hemagglutination inhibition activity of the screened Nbs against the H7 subtype hemagglutinin. Nb-Z77, with high hemagglutination inhibition activity was selected from the screened Nbs to optimize the yeast expression conditions and construct oligomeric forms of Nb-Z77 using various ligation methods. The oligomers Nb-Z77-DiGS, Nb-Z77-TriGS, Nb-Z77-Fc and Nb-Z77-Foldon were successfully constructed and expressed. Nb-Z77-DiGS and Nb-Z77-Foldon exhibited considerably greater activity than did Nb-Z77 against H7 subtype hemagglutinin, with median effective concentrations of 384.7 and 27.33 pM and binding affinity values of 213 and 5.21 pM, respectively. Nb-Z77-DiGS and Nb-Z77-Foldon completely inhibited the hemagglutination activity of the inactivated virus H7-Re1 at the lowest concentration of 0.938 μg/mL. This study screened a strain of Nb with high hemagglutination inhibition activity and enhanced its antiviral activity through oligomerization, which may have great potential for developing effective agents for the prevention, diagnosis, and treatment of AIV H7 subtype infection.

Prevalence and genomic-based antimicrobial resistance analysis of Avibacterium paragallinarum isolates in Guangdong Province, China

Infectious coryza (IC) is an acute infectious respiratory disease in chickens that is caused by Avibacterium paragallinarum (A. paragallinarum). A. paragallinarum poses a significant threat to poultry health due to its virulence and multidrug resistance. This study isolated and identified 21 A. paragallinarum isolates from Guangdong between 2022 and 2023. Biochemical tests showed that 100% of A. paragallinarum isolates fermented glucose but did not ferment alginate and galactose, and only YZ18 was nicotinamide adenine dinucleotide independent. To determine the genetic relatedness between these isolates and NCBI reference strains, whole-genome-based phylogenetic analysis was employed. In addition, analysis of the 2,000 bp-length hmtp210 gene showed that the hmtp210 gene was strongly associated with A. paragallinarum serotypes. Meanwhile, a PCR assay for serotyping A. paragallinarum was developed based on the hmtp210 gene, this assay has high sensitivity and specificity. The antimicrobial susceptibility of isolates was assessed using the disk diffusion method. The antibiotic resistance genes of isolates were analyzed using the genomic method. Phenotypic resistance to ampicillin (95.2%), streptomycin (95.2%), methotrexate-sulfamethoxazole (90.5%), and tetracycline (85.7%) was most frequent among the isolates. All of the isolates exhibited resistance to multiple drugs, and furthermore, the isolates possessed a collective total of 14 genes associated with antibiotic resistance. This study will contribute to advancing our knowledge of A. paragallinarum antibiotic resistance and provide a scientific basis for the prophylaxis and treatment of IC, and the subsequent rational design of potential clinical therapeutics.

On-column capillary suppressor for open tubular ion chromatography

BACKGROUND

Suppressors with different dead volumes are required to match different suppressed ion chromatography systems. Especially for suppressed open tubular ion chromatography (SOTIC), the dead volume is a critical parameter. Both connection tubes between open tubular (OT) columns and suppressors and the dead volumes of the suppressors should be as short/small as possible to minimize peak dispersion. Suppressors with different dead volumes are required to match the various suppressed ion chromatography systems that operate at low flow rates 20-200 nL/min.

RESULTS

We describe three designs of on-column capillary suppressors for SOTIC: (A) on-column electrodialytic suppressor prepared by making small cracks on the cycloolefin polymer (COP) capillary at targeted locations, (B) on-column electrodialytic suppressor built on a polyether ether ketone (PEEK) capillary by removing the wall materials at target locations, (C) on-column chemical suppressor based on a single cut on a PEEK capillary at a targeted location a single cut on a PEEK capillary at a targeted location. The on-column electrodialytic suppressors work in two different modes with suppression voltage applied in co-current and counter-current direction to the eluent flow. Because of very narrow column inner diameter (i.d.), up to several hundred volts were required to suppress the hydroxide eluent, but it was found the there was a >90% loss of analytes in the suppressor accompanied with a high noise level after on-column electrodialytic suppression. Theoretical analysis reveals that high suppression voltage significantly affects the retention of specific analytes by electromigration. Further analysis indicated that the electrodialytic on-column suppressor in co-current mode would behave totally different from traditional suppressors. The on-column chemical suppression, with minimum dead volume of 0.27 nL, provides fairly well suppression of low hydroxide eluent without analyte loss in the suppressor. In design C, an efficiency of 47000 ± 1800 plates/m for Cl-, corresponding to a peak volume of 17.9 ± 0.7 nL, was obtained when separating five anion mixture (0.5 mM each) in the 25 μm i.d. AS18 latex coated PEEK OT column with an injection of 7.3 nL. Theoretical calculation revealed that a column efficiency loss of ≤3% would result in a cylindrical chemical suppression channel and thus it is taken as the acceptable dispersion contribution originating from the on-column chemical suppressor.

SIGNIFICANCE

Different on-column suppressors have been designed on OT columns with i.d.s less than 30 μm. Two electrodialytic on-column suppressor designs with eluent flow parallel to the direction of electric field were proposed and tested. The eluent flow rate, analytes' retention behavior, resistance of suppression channel, current-voltage relationship, and working principles in both co-current and counter-current were experimentally investigated and comprehensively discussed. It was found that although the on-column electrodialytic suppressions (Design A and B) are not feasible in practice, the electrodialytic on-column suppressor on co-current mode has a potential of being used as an enriching capillary column for analyte ions. Design C provides fairly well chemical suppression. Theoretical calculation indicates that the loss of column efficiency can be controlled within 3%.

Anharmonic strong-coupling effects at the origin of the charge density wave in CsV3Sb5

The formation of charge density waves is a long-standing open problem, particularly in dimensions higher than one. Various observations in the vanadium antimonides discovered recently further underpin this notion. Here, we study the Kagome metal CsV3Sb5 using polarized inelastic light scattering and density functional theory calculations. We observe a significant gap anisotropy with 2 Δ max / k B T CDW ≈ 20 , far beyond the prediction of mean-field theory. The analysis of the A1g and E2g phonons, including those emerging below TCDW, indicates strong phonon-phonon coupling, presumably mediated by a strong electron-phonon interaction. Similarly, the asymmetric Fano-type lineshape of the A1g amplitude mode suggests strong electron-phonon coupling below TCDW. The large electronic gap, the enhanced anharmonic phonon-phonon coupling, and the Fano shape of the amplitude mode combined are more supportive of a strong-coupling phonon-driven charge density wave transition than of a Fermi surface instability or an exotic mechanism in CsV3Sb5.

Computational fluid dynamics-based design and in vitro characterization of a novel pediatric pump-lung

BACKGROUND

Although extracorporeal membrane oxygenation (ECMO) has been used to provide temporary support for pediatric patients suffering severe respiratory or cardiac failure since 1970, ECMO systems specifically designed for pediatric patients, particularly for long-term use, remain an unmet clinical need. We sought to develop a new pediatric ECMO system, that is, pediatric pump-lung (PPL), consisting of a unique cylinder oxygenator with an outside-in radial flow path and a centrifugal pump.

METHODS

Computational fluid dynamics was used to analyze the blood fluid field for optimized biocompatible and gas exchange performances in terms of flow characteristics, hemolysis, and gas transfer efficiency. Ovine blood was used for in vitro hemolysis and gas transfer testing.

RESULTS

Both the computational and experimental data showed that the pressure drop through the PPL's oxygenator is significantly low, even at a flow rate of more than 3.5 L/min. The PPL showed better hemolysis performance than a commercial ECMO circuit consisting of the Quadrox-iD pediatric oxygenator and the Rotaflow pump at a 3.5 L/min flow rate and 250 mm Hg afterload pressure. The oxygen transfer rate of the PPL can reach over 200 mL/min at a flow rate of 3.5 L/min.

CONCLUSIONS

The PPL has the potential to provide adequate blood pumping and excellent respiratory support with minimal risk of hemolysis for a wide range of pediatric patients.

Plasma-Promoted Ammonia Decomposition over Supported Ruthenium Catalysts for COx -Free H2 Production

The efficient decomposition of ammonia to produce COx -free hydrogen at low temperatures has been extensively investigated as a potential method for supplying hydrogen to mobile devices based on fuel cells. In this study, we employed dielectric barrier discharge (DBD) plasma, a non-thermal plasma, to enhance the catalytic ammonia decomposition over supported Ru catalysts (Ru/Y2 O3 , Ru/La2 O3 , Ru/CeO2 and Ru/SiO2 ). The plasma-catalytic reactivity of Ru/La2 O3 was found to be superior to that of the other three catalysts. It was observed that both the physicochemical properties of the catalyst (such as support acidity) and the plasma discharge behaviours exerted significant influence on plasma-catalytic reactivity. Combining plasma with a Ru catalyst significantly enhanced ammonia conversion at low temperatures, achieving near complete NH3 conversion over the 1.5 %-Ru/La2 O3 catalyst at temperatures as low as 380 °C. Under a weight gas hourly space velocity of 2400 mL gcat -1  h-1 and an AC supply power of 20 W, the H2 formation rate and energy efficiency achieved were 10.7 mol gRu -1  h-1 and 535 mol gRu -1 (kWh)-1 , respectively, using a 1.5 %-Ru/La2 O3 catalyst.

Polarized tip-enhanced Raman spectroscopy at liquid He temperature in ultrahigh vacuum using an off-axis parabolic mirror

Tip-enhanced Raman spectroscopy (TERS) combines inelastic light scattering well below the diffraction limit down to the nanometer range and scanning probe microscopy and, possibly, spectroscopy. In this way, topographic and spectroscopic as well as single- and two-particle information may simultaneously be collected. While single molecules can now be studied successfully, bulk solids are still not meaningfully accessible. It is the purpose of the work presented here to outline approaches toward this objective. We describe a home-built, liquid helium cooled, ultrahigh vacuum TERS. The setup is based on a scanning tunneling microscope and, as an innovation, an off-axis parabolic mirror having a high numerical aperture of ∼0.85 and a large working distance. The system is equipped with a fast load-lock chamber, a chamber for the in situ preparation of tips, substrates, and samples, and a TERS chamber. Base pressure and temperature in the TERS chamber were ∼3 × 10-11 mbar and 15 K, respectively. Polarization dependent tip-enhanced Raman spectra of the vibration modes of carbon nanotubes were successfully acquired at cryogenic temperature. The new features described here including very low pressure and temperature and the external access to the light polarizations, thus the selection rules, may pave the way toward the investigation of bulk and surface materials.

A transversely isotropic viscohyperelastic-damage model for the brain tissue with strain rate sensitivity

Understanding the mechanical behaviors and properties of brain tissue are crucial to study the mechanisms of traumatic brain injury (TBI). Such injury may be associated with high rate loading conditions and the large deformation of brain tissue. Thus, constitutive models that consider the rate dependent large deformation of brain tissue and its possible damage initiation and evolution may help uncover the related mechanisms of TBI. Motivated from this, in this paper we present a fully three-dimensional large strain viscohyperelastic-damage model with the purpose of reproducing the experimentally observed rate sensitive elastic and damage-induced stress softening behaviors of brain tissue. The parameters of the proposed model can be identified using the experimental data from simple monotonic tests such as uniaxial tension, compression and simple shear. The proposed model is validated by comparing its prediction with experimental data. Good agreement between predictive results and experimental data is achieved indicating the potential of the proposed model in characterizing the mechanical behaviors of brain tissue considering rate dependence and damage effect.

Modeling the damage-induced softening behavior of brain white matter using a coupled hyperelasticty-damage model

White matter in the brain is structurally anisotropic consisting of large bundle of aligned axonal fibers. Hyperelastic, transversely isotropic constitutive models are typically used in the modeling and simulation of such tissues. However, most studies constrain the material models to describe the mechanical behavior of white matter in the limit of small deformation, without considering the experimentally observed damage initiation and damage-induced material softening in large strain regime. In this study, we extend a previously developed transversely isotropic hyperelasticity model for white matter by coupling it with damage equations within the framework of thermodynamics and using continuum damage mechanics method. Two homogeneous deformation cases are used to demonstrate the proposed model's capability in capturing the damage-induced softening behaviors of white matter under uniaxial loading and simple shear, along with the investigation of fiber orientation effect on such behaviors and material stiffness. As a demonstration case of inhomogeneous deformation, the proposed model is also implemented into finite element codes to reproduce the experimental data (nonlinear material behavior and damage initiation) from an indentation configuration of porcine white matter. Good agreement between numerical results and experimental data is achieved indicating the potential of the proposed model in characterizing the mechanical behaviors of white matter considering damage at large strain.

Steric effects of CN vacancies for boosting CO2 electroreduction to CO with ultrahigh selectivity

We have reported that the CN vacancies was obtained by H2 cold plasma bombardment. The steric effect of VCN can decrease the free energy barrier of *COOH and further crack into CO under low overpotential.

Discovery of selective HDAC6 inhibitors capped by flavonoid or flavonoid-analogous moieties as anti-cancer therapeutics simultaneously harboring anti-proliferative and immunomodulatory activities

Specific HDAC6 inhibitors (HDAC6is) simultaneously harboring anti-proliferative and immunomodulatory properties may prohibit tumor progression via intrinsic and immune driven effects. Herein, built upon the structurally novel lead TFH-7, structure-activity relationship study culminated in the identification of azaflavone-capped compound 20, which exhibited comparable HDAC6 inhibitory activity (IC₅₀ = 8.5 nM) to that of Tubastatin A, a highly selective HDAC6i, as well as favorable subtype specificity. Importantly, concurrent with its impressive anti-proliferative efficacy against several solid tumor cell lines, 20 remarkably alleviated the transduction of immune-related STAT3 signaling and attenuated the expression of immunosuppressive checkpoint PD-L1 at submicromolar concentration, highlighting the immunomodulatory properties. Moreover, consistent with its favorable subtype selectivity, 20 displayed low cytotoxicity against normal human umbilical vein endothelial cells, revealing a promising safety profile. Following the intravenous administration, it demonstrated acceptable elimination half-life and exposure in Sprague-Dawley rats. Hence, the extensive functional investigation or structural modification of 20 is valuable.

Computational fluid dynamics analysis and experimental hemolytic performance of three clinical centrifugal blood pumps: Revolution, Rotaflow and CentriMag

Centrifugal blood pumps have become popular for adult extracorporeal membrane oxygenation (ECMO) due to their superior blood handling and reduced thrombosis risk featured by their secondary flow paths that avoid stagnant areas. However, the high rotational speed within a centrifugal blood pump can introduce high shear stress, causing a significant shear-induced hemolysis rate. The Revolution pump, the Rotaflow pump, and the CentriMag pump are three of the leading centrifugal blood pumps on the market. Although many experimental and computational studies have focused on evaluating the hydraulic and hemolytic performances of the Rotaflow and CentriMag pumps, there are few on the Revolution pump. Furthermore, a thorough direct comparison of these three pumps' flow characteristics and hemolysis is not available. In this study, we conducted a computational and experimental analysis to compare the hemolytic performances of the Revolution, Rotaflow, and CentriMag pumps operating under a clinically relevant condition, i.e., the blood flow rate of 5 L/min and pump pressure head of 350 mmHg, for adult ECMO support. In silico simulations were used to characterize the shear stress distributions and predict the hemolysis index, while in vitro blood loop studies experimentally determined hemolysis performance. Comparative simulation results and experimental data demonstrated that the CentriMag pump caused the lowest hemolysis while the Revolution pump generated the highest hemolysis.

Numerical study of the effect of LVAD inflow cannula positioning on thrombosis risk

Left ventricular assist devices (LVADs) have been increasingly used as a therapy for patients with end-stage heart failure. However, a growing number of clinical observations have shown that LVADs are associated with thromboembolic events, which are potentially related to the changes in intraventricular flow. Particularly, the flow fields around the inflow cannula (IC) of the LVAD. In this study, a fluid structure interaction (FSI) simulation was conducted to evaluate the hemodynamics of a patient specific left ventricle (LV) with varying LVAD IC orientations. The LV model was obtained from computed tomography scans and modeled to have contraction and relaxation during cardiac cycles following available experimental data of LV volume changes. The LV of the patient was assumed to have an end systolic volume of 223.7 mL and a stroke volume of 46.4 mL. Four different IC positions were considered: towards the (1) septum; (2) aortic valve (AV); (3) mitral valve (MV) and (4) inferior wall (IW). The potential thrombus growth around the IC was assumed to be caused by blood stagnation regions with low velocity (<5 mm/s) and low shear rate (<60/s) flow. Mean velocity magnitudes and low blood velocity regions around the IC were numerically obtained. To quantitatively compare the thrombosis risks of the four simulation cases, the time-averaged volumes of the low-velocity regions and the low shear rate regions were calculated. The intraventricular volumes of low velocity zones based on IC orientation are 1.42 mL toward the septum, 1.14 mL toward the AV, 0.93 mL toward the MV, and 1.24 mL toward the IW. The intraventricular volumes of low shear regions based on IC orientation are 11.54 mL toward the septum, 11.15 mL toward the AV, 9.24 mL toward the MV, and 10.7 mL toward the IW. IC orientation toward the MV results in lower volumetric regions of low flow and low shear within the ventricle, which consequently may lead to a reduced risk of thrombus formation.

Ni@CNTs/Al2O3 Ceramic Composites with Interfacial Solder Strengthen the Segregated Network for High Toughness and Excellent Electromagnetic Interference Shielding

Ingenious microstructure design and appropriate multicomponent strategies are still challenging for advanced electromagnetic interference (EMI) shielding materials with excellent shielding effectiveness (SE) and reliable mechanical properties in harsh environments and low filling levels. In this study, nickel@multiwalled carbon nanotubes/alumina (Ni@CNTs/Al₂O₃) ceramic composites with segregated structures and electric/magnetic-coupling networks anchored by CNTs and magnetic Ni nanofillers were prepared by hot-press sintering. CNTs/Al₂O₃ ceramic composites exhibit a percolation threshold of only about 0.32013 vol %, which is lower than those of other reported CNTs/Al₂O₃ composites with segregated or uniformly dispersed structures. The electrical conductivity and EMI SE of 9CNTs/Al₂O₃ ceramic composites with 9 vol % (4.76 wt %) CNT content were 103.1 S/m and 33.6 dB, respectively. In addition, EMI SE and toughness were both enhanced by the synergistic effect of Ni nanoparticles and CNTs. In the unit of a segregated structure, a three-dimensional (3D) electric/magnetic-coupling network effectively captures and attenuates electromagnetic wave energy by electrical conduction, dielectric loss, and magnetic loss. On the other hand, the pull-out of CNTs and deflection of cracks distributed along the segregated structures synergistically enhance the fracture toughness of Ni@CNTs/Al₂O₃ ceramic composites. High-performance 3Ni@5CNTs/Al₂O₃ ceramic composites with 5 vol % (2.64 wt %) and 3 vol % (0.76 wt %) CNT contents have been achieved, whose EMI SE is 41.8 dB, density is 90.99%, flexural strength is 197.83 ± 18.62 MPa, and fracture toughness is 6.03 ± 0.23 MPa·m^1/2. This efficient method provides a promising way to fabricate EMI shielding ceramic composites with high mechanical properties.

Microstructural transition of poly(vinyl alcohol)-based aerogels in the presence of interpolymer complexes

Interpolymer interactions play a vital role of determining the microstructure and properties of polymer aerogels.

Dual performance of environmental regulation on economic and environmental development: evidence from China

Based on the comparative perspective of environmental regulation performance, this paper uses the threshold effect model to analyze the nonlinear characteristics of the impact of environmental regulation on economic development and environmental pollution and explore the dual performance of environmental regulation on economic and environmental development. The results are fourfold: Firstly, the intensity of fiscal expenditure on energy conservation and environmental protection has a restraining effect on environmental pollution, but it has a crowding-out effect on economic growth. Therefore, it is impossible to achieve a win-win situation between ecological protection and economic development by increasing the intensity of financial expenditure on energy conservation and environmental protection. Secondly, giving more financial rights to local governments in eastern China may help to reverse the non-win-win situation of the economy and the environment. Thirdly, increasing the environmental protection awareness of local governments will help to achieve a win-win situation. It is more effective to achieve a win-win situation of ecology and economy using constraint regulation than incentive regulation. Finally, the economic development level of the last period has different threshold effects on the current environmental pollution in the eastern and western China. Thus, the impact of environmental regulation lags. We conclude that we should give full play to the role of the environmental regulation, stimulate the endogenous power of environmental system, accurately implement the key differentiation strategy, and promote the win-win situation of ecological protection and economic development.

Mesoscale Simulation-based Parametric Study of Damage Potential in Brain Tissue Using Hyperelastic and Internal State Variable Models

Two-dimensional mesoscale finite element analysis (FEA) of a multi-layered brain tissue was performed to calculate the damage related average stress triaxiality and local maximum von Mises strain in the brain. The FEA was integrated with rate dependent hyperelastic and internal state variable (ISV) models respectively describing the behaviors of wet and dry brain tissues. Using the finite element results, a statistical method of design of experiments (DOE) was utilized to independently screen the relative influences of seven parameters related to brain morphology (sulcal width/depth, gray matter (GM) thickness, cerebrospinal fluid (CSF) thickness and brain lobe) and loading/environment conditions (strain rate and humidity) with respect to the potential damage growth/coalescence in the brain tissue. The results of the parametric study illustrated that the GM thickness and humidity were the two most crucial parameters affecting average stress triaxiality. For the local maximum von Mises strain at the depth of brain sulci, the brain lobe/region was the most influential factor. The conclusion of this investigation gives insight for the future development and refinement of a macroscale brain damage model incorporating information from lower length scale.

Analysing neutron radiation damage in YBa2 Cu3 O7-x high temperature superconductor tapes

Superconducting windings will be necessary in future fusion reactors to generate the strong magnetic fields needed to confine the plasma, and these superconducting materials will inevitably be exposed to neutron damage. It is known that this exposure results in the creation of isolated damage cascades, but the presence of these defects alone is not sufficient to explain the degradation of macroscopic superconducting properties and a quantitative method is needed to assess the subtle lattice damage in between the clusters. We have studied REBCO coated conductors irradiated with neutrons to a cumulative dose of 3.3×10²²  n*m^-2  that show a degradation of both T_c  and J_c values, and use HRTEM analysis to show that this irradiation introduces ∼10 nm amorphous collision cascades. In addition we introduce a new method for the analysis of these images to quantify the degree of lattice disorder in the apparently perfect matrix between these cascades. This method utilises Fast Fourier and Discrete Cosine Transformations of a statistically-relevant number of HRTEM images of pristine, neutron-irradiated, and amorphous samples, and extracts the degree of randomness in terms of entropy values. Our results show that these entropy values in both mid-frequency band FFT and DCT domains correlate with the expected level of lattice damage, with the pristine samples having the lowest and the fully amorphous regions the highest entropy values.  Our methodology allows us to quantify 'invisible' lattice damage to and correlate these values to the degradation of superconducting properties, and also has relevance for a wider range of applications in the field of electron microscopy where small changes in lattice perfection need to be measured. This article is protected by copyright. All rights reserved.

Flow characteristics and hemolytic performance of the new Breethe centrifugal blood pump in comparison with the CentriMag and Rotaflow pumps

Blood pumps have been increasingly used in mechanically assisted circulation for ventricular assistance and extracorporeal membrane oxygenation support or during cardiopulmonary bypass for cardiac surgery. However, there have always been common complications such as thrombosis, hemolysis, bleeding, and infection associated with current blood pumps in patients. The development of more biocompatible blood pumps still prevails during the past decades. As one of those newly developed pumps, the Breethe pump is a novel extracorporeal centrifugal blood pump with a hybrid magnetic and mechanical bearing with attempt to reduce device-induced blood trauma. To characterize the hydrodynamic and hemolytic performances of this novel pump and demonstrate its superior biocompatibility, we use a combined computational and experimental approach to compare the Breethe pump with the CentriMag and Rotaflow pumps in terms of flow features and hemolysis under an operating condition relevant to ECMO support (flow: 5 L/min, pressure head: ~350 mmHg). The computational results showed that the Breethe pump has a smaller area-averaged wall shear stress (WSS), a smaller volume with a scalar shear stress (SSS) level greater than 100 Pa and a lower device-generated hemolysis index compared to the CentriMag and Rotaflow pumps. The comparison of the calculated residence times among the three pumps indicated that the Breethe pump might have better washout. The experimental data from the in vitro hemolysis testing demonstrated that the Breethe pump has the lowest normalized hemolysis index (NIH) than the CentriMag and Rotaflow pumps. It can be concluded based on both the computational and experimental data that the Breethe pump is a viable pump for clinical use and it has better biocompatibility compared to the clinically accepted pumps.

An online optimization strategy for a fluid catalytic cracking process using a case-based reasoning method based on big data technology

Rigorous mechanistic models of refining processes are often too complex, which results in long modeling times, low model computational efficiencies, and poor convergence, limiting the application of mechanistic-model-based process optimization and advanced control in complex refining production processes. To address this problem and take advantage of big data technology, this study used case-based reasoning (CBR) for process optimization. The proposed method makes full use of previous process cases and reuses previous process cases to solve production optimization problems. The proposed process optimization method was applied to an actual fluid catalytic cracking maximizing iso-paraffins (MIP) production process for industrial validation. The results showed that the CBR method can be used to obtain optimization results under different optimization objectives, with a solution time not exceeding 1 s. The CBR method based on big data technology proposed in this study provides a feasible solution for fluid catalytic cracking to achieve online process optimization.

The case-based reasoning (CBR) method based on big data technology proposed in this study provides a feasible solution for fluid catalytic cracking to achieve online process optimization.

[Mn2+-doped Prussian blue nanoparticles for T1-T2 dual-mode magnetic resonance imaging and photothermal therapy in vitro]

OBJECTIVE

To prepare Mn²⁺-doped Prussian blue nanoparticles (Mn-PB NPs) for T1-T2 dual-mode magnetic resonance imaging (MRI) and photothermal therapy in vitro.

OBJECTIVE

Mn-PB NPs were prepared based on manganese chloride, ferrous chloride and potassium ferricyanide using the microemulsion method. The performance of T1-T2 dual-mode MRI with Mn-PB NPs and the photothermal property of the nanoparticles were assessed. CCK-8 assay and AM/PI double staining were used to evaluate the effect of photothermal therapy in vitro using the parepared nanoparticles.

OBJECTIVE

The prepared Mn-PB NPs had a mean particle size of 39.46±0.42 nm with a Zeta potential of -25.9±1.2 mV and exhibited a good dispersibility and uniform particle size. In MRI using the nanoparticles, the r1 and r2 values reached 0.68 and 3.65 (mmol/L)^-1s^-1, respectively, indicating good performance of Mn-PB NPs for T1 and T2 enhancement in MRI. When irradiated with 808 nm laser for 10 min, Mn-PB NPs showed a temperature rise to 90 ℃ to cause significant reduction of cell survival. CCK-8 assay and AM/PI double staining confirmed that Mn-PB NPs were capable of efficient killing of HepG2 cells upon 808 nm laser irradiation.

OBJECTIVE

The Mn-PB NPs prepared in this work have uniform particle size and show good performances both in MRI for T1 and T2 enhancement and in photothermal therapy in vitro without obvious cytotoxicity.

Histological analysis of spermatogenesis and the germ cell seasonal development within the testis of domesticated tree shrews (Tupaia belangeri chinensis)

This study aimed to address the lack of information on the male germ cell seasonal development of domesticated tree shrews (Tupaia belangeri chinensis). Testicular tissues were collected from 60 tree shrews (n=5 per month). The ultrastructures of the testes and spermatids were examined via transmission electron microscopy. Apoptosis of spermatogenic cells was measured through terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The expression of proliferation factors, namely, proliferating cell nuclear antigen (PCNA) and Ki67, in testicular tissues was assayed through immunohistochemistry. Spermatids ultrastructure showed seasonal differences, and spermatogenesis was relatively active in June and July and relatively stagnant from October to November. The percentage of TUNEL-positive germ cells was less during October and November, while greater in July than other phases. The number of PCNA-nucleus-positive germ cells was most in June and July, but with cytoplasm staining from October to November. Ki67 presented positive expression in the testes from April to September, with highest expression in June, but with no expression from October to March. In summary, there are seasonal differences in tissue morphology related to spermatogenesis in domesticated tree shrews. PCNA expression and Ki67 expression are good indicators of seasonal differences in male germ cells.

Remote Mesoscopic Signatures of Induced Magnetic Texture in Graphene

Mesoscopic conductance fluctuations are a ubiquitous signature of phase-coherent transport in small conductors, exhibiting universal character independent of system details. In this Letter, however, we demonstrate a pronounced breakdown of this universality, due to the interplay of local and remote phenomena in transport. Our experiments are performed in a graphene-based interaction-detection geometry, in which an artificial magnetic texture is induced in the graphene layer by covering a portion of it with a micromagnet. When probing conduction at some distance from this region, the strong influence of remote factors is manifested through the appearance of giant conductance fluctuations, with amplitude much larger than e^{2}/h. This violation of one of the fundamental tenets of mesoscopic physics dramatically demonstrates how local considerations can be overwhelmed by remote signatures in phase-coherent conductors.

Comprehensive Machine Learning-Based Model for Predicting Compressive Strength of Ready-Mix Concrete

Considering that compressive strength (CS) is an important mechanical property parameter in many design codes, in order to ensure structural safety, concrete CS needs to be tested before application. However, conducting CS tests with multiple influencing variables is costly and time-consuming. To address this issue, a machine learning-based modeling framework is put forward in this work to evaluate the concrete CS under complex conditions. The influential factors of this process are systematically categorized into five aspects: man, machine, material, method and environment (4M1E). A genetic algorithm (GA) was applied to identify the most important influential factors for CS modeling, after which, random forest (RF) was adopted as the modeling algorithm to predict the CS from the selected influential factors. The effectiveness of the proposed model was tested on a case study, and the high Pearson correlation coefficient (0.9821) and the low mean absolute percentage error and delta (0.0394 and 0.395, respectively) indicate that the proposed model can deliver accurate and reliable results.

Correction: Combined mechanistic and genetic programming approach to modeling pilot NBR production: influence of feed compositions on rubber Mooney viscosity

Correction for ‘Combined mechanistic and genetic programming approach to modeling pilot NBR production: influence of feed compositions on rubber Mooney viscosity’ by Ge He et al., RSC Adv., 2021, 11, 817–829, DOI: 10.1039/D0RA07257E.

Combined mechanistic and genetic programming approach to modeling pilot NBR production: influence of feed compositions on rubber Mooney viscosity

Mooney viscosity is an essential parameter in quality control during the production of nitrile-butadiene rubber (NBR) by emulsion polymerization. A process model that could help understand the influence of feed compositions on the Mooney viscosity of NBR products is of vital importance for its intelligent manufacture. In this work, a process model comprised of a mechanistic model based on emulsion polymerization kinetics and a data-driven model derived from genetic programming (GP) for Mooney viscosity is developed to correlate the feed compositions (including impurities) and process conditions to Mooney viscosity of NBR products. The feed compositions are inputs of the mechanistic model to generate the number-, weight-averaged molecular weights (M n, M w) and branching degree (BRD) of NBR polymers. With these generated data, the GP model is used to output the optimal correlation for the Mooney viscosity of NBR. In a pilot NBR production, Mooney viscosity data of NBR predicted by the process model agree quite well with experimental values. Furthermore, the process model enables the analyses of the univariate and multivariate influence of feed compositions on NBR Mooney viscosity, and the variables include the contents of vinyl acetylene and dimer in 1,3-butadiene, as well as the mass flow rate of the chain transfer agent (CTA) in the process. Based on the results, it is recommended to control the content of vinyl acetylene in the 1,3-butadiene feed below 14 ppm and the content of dimer below 1100 ppm. This developed process model would help stabilize NBR viscosity for a better control of the product quality.

Model-Based Design and Optimization of Blood Oxygenators

Blood oxygenators, also known as artificial lungs, are widely used in cardiopulmonary bypass surgery to maintain physiologic oxygen (O₂) and carbon dioxide (CO₂) levels in blood, and also serve as respiratory assist devices to support patients with lung failure. The time- and cost-consuming method of trial and error is initially used to optimize the oxygenator design, and this method is followed by the introduction of the computational fluid dynamics (CFD) that is employed to reduce the number of prototypes that must be built as the design is optimized. The CFD modeling method, while having progress in recent years, still requires complex three-dimensional (3D) modeling and experimental data to identify the model parameters and validate the model. In this study, we sought to develop an easily implemented mathematical models to predict and optimize the performance (oxygen partial pressure/saturation, oxygen/carbon dioxide transfer rates, and pressure loss) of hollow fiber membrane-based oxygenators and this model can be then used in conjunction with CFD to reduce the number of 3D CFD iteration for further oxygenator design and optimization. The model parameters are first identified by fitting the model predictions to the experimental data obtained from a mock flow loop experimental test on a mini fiber bundle. The models are then validated through comparing the theoretical results with the experimental data of seven full-size oxygenators. The comparative analysis show that the model predictions and experimental results are in good agreement. Based on the verified models, the design curves showing the effects of parameters on the performance of oxygenators and the guidelines detailing the optimization process are established to determine the optimal design parameters (fiber bundle dimensions and its porosity) under specific system design requirements (blood pressure drop, oxygen pressure/saturation, oxygen/carbon dioxide transfer rates, and priming volume). The results show that the model-based optimization method is promising to derive the optimal parameters in an efficient way and to serve as an intermediate modeling approach prior to complex CFD modeling.

Cereal production in the presence of climate change in China

This study sought to investigate the impacts of climate change on cereal production in China over the period 1990Q1-2013Q4. Using the Autoregressive Distributed Lag (ARDL) approach, the results showed that CO₂ emissions, average temperature, and temperature variability have a significant negative impact on cereal production in the long run. However, energy consumption, average rainfall, labor force, and cultivated area significantly and positively influenced the production of cereal crops in the long run. Meanwhile, the study observed that rainfall variability has no significant effect on cereal production in the long run. The study again found that in the short run, CO₂ emissions, average temperature, and temperature variability have a significant negative relationship with cereal production. Besides, energy consumption, average rainfall, rainfall variability, labor force, and the cultivated area had a significant positive association with cereal production in the short run. The results of the Granger causality test showed that there exists a unidirectional causality running from CO₂ emissions, energy consumption, and labor force to the production of cereal crops in China. On the contrary, the study found no causality between cultivated area and cereal production. The study suggests that improved cereal crop varieties ought to be developed and introduced to cope with the adverse impacts of climate change in China. This will help to circumvent Huang et al.'s (2017) prediction of a decline in the total food self-sufficiency of China from 94.5% in 2015 to about 91% by 2025.

Raman Study of Cooper Pairing Instabilities in (Li_{1-x}Fe_{x})OHFeSe

We studied the electronic Raman spectra of (Li_{1-x}Fe_{x})OHFeSe as a function of light polarization and temperature. In the B_{1g} spectra alone we observe the redistribution of spectral weight expected for a superconductor and two well-resolved peaks below T_{c}. The nearly resolution-limited peak at 110  cm^{-1} (13.6 meV) is identified as a collective mode. The peak at 190  cm^{-1} (23.6 meV) is presumably another collective mode since the line is symmetric and its energy is significantly below the gap energy observed by single-particle spectroscopies. Given the experimental band structure of (Li_{1-x}Fe_{x})OHFeSe, the most plausible explanations include conventional spin-fluctuation pairing between the electron bands and the incipient hole band and pairing between the hybridized electron bands. The absence of gap features in A_{1g} and B_{2g} symmetry favors the second case. Thus, in spite of various differences between the pnictides and chalcogenides, this Letter demonstrates the proximity of pairing states and the importance of band structure effects in the Fe-based compounds.

Universal scaling of weak localization in graphene due to bias-induced dispersion decoherence

The differential conductance of graphene is shown to exhibit a zero-bias anomaly at low temperatures, arising from a suppression of the quantum corrections due to weak localization and electron interactions. A simple rescaling of these data, free of any adjustable parameters, shows that this anomaly exhibits a universal, temperature- (T) independent form. According to this, the differential conductance is approximately constant at small voltages (V < kBT/e), while at larger voltages it increases logarithmically with the applied bias. For theoretical insight into the origins of this behaviour, which is inconsistent with electron heating, we formulate a model for weak-localization in the presence of nonequilibrium transport. According to this model, the applied voltage causes unavoidable dispersion decoherence, which arises as diffusing electron partial waves, with a spread of energies defined by the value of the applied voltage, gradually decohere with one another as they diffuse through the system. The decoherence yields a universal scaling of the conductance as a function of eV/kBT, with a logarithmic variation for eV/kBT > 1, variations in accordance with the results of experiment. Our theoretical description of nonequilibrium transport in the presence of this source of decoherence exhibits strong similarities with the results of experiment, including the aforementioned rescaling of the conductance and its logarithmic variation as a function of the applied voltage.

Effects of wet atmospheric nitrogen deposition on epiphytic lichens in the subtropical forests of Central China: Evaluation of the lichen food supply and quality of two endangered primates

Over the last few decades, the threat posed to biodiversity and ecosystem function by atmospheric nitrogen (N) deposition has been increasingly recognized. The disturbed nutrient balance and species composition of plants induced by higher N deposition can impact the biodiversity of the organisms that consume the plants. In this research, we implemented several experiments to estimate the effects of increased N deposition on the growth, survival, and nutrients of the dominant epiphytic lichens in the subtropical mountains in Central China to assess the lichen food amount and nutritional quality for two endangered primates endemic to China. Our results indicated that the thallus growth and propagule survival of the lichens were significantly decreased when nitrogen addition changed from 6.25 to 50.0 kg N·ha^-1·y^-1; it was also shown that lichen biomass could be decreased by 11.2%-70.2% when the deposition addition exceeded 6.25 kg N·ha^-1·y^-1. Further, our study revealed that increased nitrogen deposition also reduced the nutritional quality of the lichens via reducing the soluble protein and soluble sugar levels and increasing the fiber content, which would substantially affect the diet selection of the plants consumers in the region, particularly the populations of the two lichen-eating endangered primate species, Rhinopithecus roxellana and R. bieti. Our experimental study suggested that the nitrogen pollution derived from anthropogenic activities could cause cascading effects for the whole forest ecosystem of Central China; thus, more studies about nitrogen deposition in this region are required.

Combinatorial laser molecular beam epitaxy system integrated with specialized low-temperature scanning tunneling microscopy

We present a newly developed facility comprising a combinatorial laser molecular beam epitaxy system and an in situ scanning tunneling microscope (STM). This facility aims at accelerating the materials research in a highly efficient way by advanced high-throughput film synthesis techniques and subsequent fast characterization of surface morphology and electronic states. Compared with uniform films deposited by conventional methods, the so-called combinatorial thin films will be beneficial in determining the accurate phase diagrams of different materials due to the improved control of parameters such as chemical substitution and sample thickness resulting from a rotary-mask method. A specially designed STM working under low-temperature and ultrahigh vacuum conditions is optimized for the characterization of combinatorial thin films in an XY coarse motion range of 15 mm × 15 mm with submicrometer location precision. The overall configuration and some key aspects such as the sample holder design, scanner head, and sample/tip/target transfer mechanism are described in detail. The performance of the device is demonstrated by synthesizing high-quality superconducting FeSe thin films with gradient thickness and imaging surfaces of highly oriented pyrolytic graphite, Au (111), Bi₂Sr₂CaCu₂O_8+δ (BSCCO), and FeSe. In addition, we also have obtained clean noise spectra of tunneling junctions and the superconducting energy gap of BSCCO. The successful manufacturing of such a facility opens a new window for the next generation equipment designed for experimental materials research.

In situ construction of dual-morphology ZnCo2O4 for high-performance asymmetric supercapacitors

In this study, the controllable preparation of ZnCo₂O₄ with different morphologies in a reaction system and the orderly weaving of these morphologies into special structures was demonstrated, which might be impossible to achieve using other methods; herein, we successfully prepared a dual-morphology ZnCo₂O₄/N-doped reduced graphene oxide/Ni foam substrate (ZNGN) electrode by ultrasonic processing, a one-step hydrothermal method and a subsequent annealing process for high-performance supercapacitors. At first, ZnCo₂O₄ nanosheet orderly formed a honeycomb structure on the surface of Ni foam (NF); this improved the redox surface area of the electrode; then, feather-like ZnCo₂O₄ was evenly distributed over the honeycomb structure, playing the role of containment and fixation to provide space for material volume expansion during charging and discharging. The electrochemical test showed that the maximum capacitance of the ZNGN electrode was 1600 F g^-1 (960C g^-1) at the current density of 1 A g^-1 in a 6 M KOH solution. Moreover, the asymmetric supercapacitor ZNGN//activated carbon (ZNGN//AC) displayed the excellent energy density of 66.1 W h kg^-1 at the power density of 701 W kg^-1. Compared with the capacitance (233.3 F g^-1 and 326.6C g^-1) when ZNGN//AC was fully activated at 4 A g^-1, there was almost no loss in capacitance after 2000 charge-discharge cycles, and a 94% capacitance retention was achieved after 5000 cycles. Thus, this excellent electrochemical property highlights the potential application of the dual-morphology ZnCo₂O₄ electrode in supercapacitors.

Isolation of H8N4 avian influenza virus from wild birds in Shanghai, China

The H8 subtype viruses are rarely isolated from wild ducks. Shanghai is one of the important wintering or stopover sites on the East Asia-Australia Migration Flyway. An influenza virus, subtype H8N4, was firstly isolated from a common teal (Anas crecca) in Shanghai during 2017-2018 in this study. To clarify the genetic characteristics of the H8N4 virus, the whole genome sequences were analyzed. Phylogenetic analysis of the hemagglutinin and neuraminidase genes showed that they shared highest nucleotide identity (99.19%-99.64%) with the Japan duck-origin H8N4 virus collected in 2016 (A/duck/Aichi/231003/2016) and belonged to the Eurasian-like avian lineage. Six other genes of the H8N4 isolated virus were all highly similar to the corresponding genes of a wide range of AIV subtypes including H9N2, H5N7, H3N8, H1N2, H4N6 and H1N1. The results indicated that the H8N4 virus was a multiple reassortant virus. The study emphasized that the continuous surveillance of influenza virus in wild birds should be strengthened. Keywords: avian influenza virus; H8N4; phylogenetic analysis; Shanghai.