Strengths, weaknesses, and applications of computational axial lithography in tissue engineering

Recently,Kelly and colleagues[1],inspired by computed tomography(CT),report a“volumetric additive manufacturing”technology via a computed axial lithography(CAL)approach.A related US patent application[2]has also been filed.The cumulative light exposure solidifies the material in the target area,while the other area remains uncured,resulting in only specific points in the designed 3D objects being printed.This technology significantly improves the capability of the digital light processing(DLP)technique.Meanwhile,the lithography approach based on a similar algorithm was already proposed by Xiang Wu in a patent(application No.PCT/CN2016/080097)in 2016[3].

Topological phases and edge modes of an uneven ladder

We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by the closure of either direct or indirect bandgaps.It also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge accumulation.We also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band continuum.Furthermore,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the quasimomentum.In this way,the topological phases can be efficiently extracted through winding numbers.We propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.

Disturbance failure mechanism of highly stressed rock in deep excavation:Current status and prospects

This article reviews the current status on the dynamic behavior of highly stressed rocks under disturbances.Firstly,the experimental apparatus,methods,and theories related to the disturbance dynamics of deep,high-stress rock are reviewed,followed by the introduction of scholars’research on deep rock deformation and failure from an energy perspective.Subsequently,with a backdrop of highstress phenomena in deep hard rock,such as rock bursts and core disking,we delve into the current state of research on rock microstructure analysis and residual stresses from the perspective of studying the energy storage mechanisms in rocks.Thereafter,the current state of research on the mechanical response and the energy dissipation of highly stressed rock formations is briefly retrospected.Finally,the insufficient aspects in the current research on the disturbance and failure mechanisms in deep,highly stressed rock formations are summarized,and prospects for future research are provided.This work provides new avenues for the research on the mechanical response and damage-fracture mechanisms of rocks under high-stress conditions.

Evolution of nonmetallic inclusions in 80-t 9CrMoCoB large-scale ingots during electroslag remelting process

In combination with theoretical calculations,experiments were conducted to investigate the evolution behavior of nonmetallic inclusions(NMIs)during the manufacture of large-scale heat-resistant steel ingots using 9CrMoCoB heat-resistant steel and CaF_(2)–CaO–Al_(2)O_(3)–SiO_(2)–B_(2)O_(3)electroslag remelting(ESR)-type slag in an 80-t industrial ESR furnace.The main types of NMI in the consumable electrode comprised pure alumina,a multiphase oxide consisting of an Al_(2)O_(3)core and liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO shell,and M_(23)C_(6)carbides with an MnS core.The Al_(2)O_(3)and MnS inclusions had higher precipitation temperatures than the M_(23)C_(6)-type carbide under equilibrium and nonequilibrium solidification processes.Therefore,inclusions can act as nucleation sites for carbide layer precipitation.The ESR process completely removed the liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO oxide and MnS inclusion with a carbide shell,and only the Al_(2)O_(3)inclusions and Al_(2)O_(3)core with a carbide shell occupied the remelted ingot.The M_(23)C_(6)-type carbides in steel were determined as Cr_(23)C_(6)based on the analysis of transmission electron microscopy results.The substitution of Cr with W,Fe,or/and Mo in the Cr_(23)C_(6)lattice caused slight changes in the lattice parameter of the Cr_(23)C_(6)carbide.Therefore,Cr_(21.34)Fe_(1.66)C_(6),(Cr_(19)W_(4)C_(6),Cr_(18.4)Mo_(4.6)C_(6),and Cr_(16)Fe_(5)Mo_(2)C_(6)can match the fraction pattern of Cr_(23)C_(6)carbide.The Al_(2)O_(3)inclusions in the remelted ingot formed due to the reduction of CaO,SiO_(2),and MnO components in the liquid inclusion.The increased Al content in liquid steel or the higher supersaturation degree of Al_(2)O_(3)precipitation in the remelted ingot than that in the electrode can be attributed to the evaporation of CaF_(2)and the increase in CaO content in the ESR-type slag.

Evaluation of large language models for the classification of medical device software

Amidst the rapidly expanding integration of large language models(LLMs)across various sectors(ranging from everyday applications to specialized fields demanding stringent regulatory adherence),our investigation seeks to determine how well these models can support medical device software classification.Medical device classification functions to systematically categorize devices according to their designated use,associated risk levels,and requisite regulatory oversight,thereby providing a structured framework for ensuring safety and efficacy as mandated by regulatory authorities.

Effect of hafnium and molybdenum addition on inclusion characteristics in Co-based dual-phase high-entropy alloys

Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature applications.In this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5)Mn_(7.5)Ni_(7.5)(at%)was chosen.The refractory metallic elements hafnium(Hf)and molybdenum(Mo)were added in small amounts(1.5at%)because of their well-known positive effects on high-temperature properties.Inclusion characteristics were comprehensively explored by using a two-dimensional cross-sectional method and extracted by using a three-dimensional electrolytic extraction method.The results revealed that the addition of Hf can reduce Al_(2)O_(3)inclusions and lead to the formation of more stable Hf-rich inclusions as the main phase.Mo addition cannot influence the inclusion type but could influence the inclusion characteristics by affecting the physical parameters of the HEA melt.The calculated coagulation coefficient and collision rate of Al_(2)O_(3)inclusions were higher than those of HfO_(2)inclusions,but the inclusion amount played a larger role in the agglomeration behavior of HfO_(2)and Al_(2)O_(3)inclusions.The impurity level and active elements in HEAs were the crucial factors affecting inclusion formation.

Geographical Accessibility to Basic Infrastructures and Services in Rural Senegal: The Case of the Niakhar Area

Access to basic infrastructure and services is a factor in economic development and an important aspect in combatting social and spatial disparities. But this access is often subject to several constraints, including geographical accessibility. In this article, we aim to analyze the geographical accessibility to basic infrastructure and services in the Niakhar area, using the improved two step floating catchment area method and local spatial association indicators. The results reveal that the areas with high accessibility to health and education infrastructures and services are mainly located along the south-east and north-west gradient, while those with low accessibility are found in the south-west and north-east center. They also show high accessibility to trade services in the center of the study area.

Applications of advanced signal processing and machine learning in the neonatal hypoxic-ischemic electroencephalography

Perinatal hypoxic-ischemic-encephalopathy significantly contributes to neonatal death and life-long disability such as cerebral palsy. Advances in signal processing and machine learning have provided the research community with an opportunity to develop automated real-time identification techniques to detect the signs of hypoxic-ischemic-encephalopathy in larger electroencephalography/amplitude-integrated electroencephalography data sets more easily. This review details the recent achievements, performed by a number of prominent research groups across the world, in the automatic identification and classification of hypoxic-ischemic epileptiform neonatal seizures using advanced signal processing and machine learning techniques. This review also addresses the clinical challenges that current automated techniques face in order to be fully utilized by clinicians, and highlights the importance of upgrading the current clinical bedside sampling frequencies to higher sampling rates in order to provide better hypoxic-ischemic biomarker detection frameworks. Additionally, the article highlights that current clinical automated epileptiform detection strategies for human neonates have been only concerned with seizure detection after the therapeutic latent phase of injury. Whereas recent animal studies have demonstrated that the latent phase of opportunity is critically important for early diagnosis of hypoxic-ischemic-encephalopathy electroencephalography biomarkers and although difficult, detection strategies could utilize biomarkers in the latent phase to also predict the onset of future seizures.

Elastic Aerogels of Cellulose Nanofibers@Metal–Organic Frameworks for Thermal Insulation and Fire Retardancy

Metal–organic frameworks(MOFs)with high microporosity and relatively high thermal stability are potential thermal insulation and flame-retardant materials.However,the difficulties in processing and shaping MOFs have largely hampered their applications in these areas.This study outlines the fabrication of hybrid CNF@MOF aerogels by a stepwise assembly approach involving the coating and cross-linking of cellulose nanofibers(CNFs)with continuous nanolayers of MOFs.The cross-linking gives the aerogels high mechanical strength but superelasticity(80%maximum recoverable strain,high specific compression modulus of^200 MPa cm3 g−1,and specific stress of^100 MPa cm3 g−1).The resultant lightweight aerogels have a cellular network structure and hierarchical porosity,which render the aerogels with relatively low thermal conductivity of^40 mW m−1 K−1.The hydrophobic,thermally stable MOF nanolayers wrapped around the CNFs result in good moisture resistance and fire retardancy.This study demonstrates that MOFs can be used as efficient thermal insulation and flame-retardant materials.It presents a pathway for the design of thermally insulating,superelastic fire-retardant nanocomposites based on MOFs and nanocellulose.

Seismic analysis of structures with a fractional derivative model of viscoelastic dampers

Viscoelastic dampers are now among some of the preferred energy dissipation devices used for passive seismic response control.To evaluate the performance of structures installed with viscoelastic dampers,different analytical models have been used to characterize their dynamic force deformation characteristics.The fractional derivative models have received favorable attention as they can capture the frequency dependence of the material stiffness and damping properties observed in the tests very well.However,accurate analytical procedures are needed to calculate the response of structures with such damper models.This paper presents a modal analysis approach,similar to that used for the analysis of linear systems,for solving the equations of inotion with fractional derivative terms for arbitrary forcing functions such as those caused by earthquake induced ground motions.The uncoupled modal equations still have fractional derivatives,but can be solved by numerical or analytical procedures.Both numerical and analytical procedures are formulated.These procedures are then used to calculate the dynamic response of a multi-degree of fleedom shear beam structure excited by ground motions. Numerical results demonstrating the response reducing effect of viscoelastic dampers are also presented.

Mechanical response and stability analysis of rock mass in high geostress underground powerhouse caverns subjected to excavation

To investigate the stability of rock mass in high geostress underground powerhouse caverns subjected to excavation,a microseismic(MS)monitoring system was established and the discrete element method(DEM)-based numerical simulation was carried out.The tempo-spatial damage characteristics of rock mass were analyzed.The evolution laws of MS source parameters during the formation of a rock collapse controlled by high geostress and geological structure were investigated.Additionally,a three-dimensional DEM model of the underground powerhouse caverns was built to reveal the deformation characteristics of rock mass.The results indicated that the MS events induced by excavation of high geostress underground powerhouse caverns occurred frequently.The large-stake crown of the main powerhouse was the main damage area.Prior to the rock collapse,the MS event count and accumulated energy release increased rapidly,while the apparent stress sharply increased and then decreased.The amount and proportion of shear and mixed MS events remarkably increased.The maximum displacement was generally located near the spandrel areas.The MS monitoring data and numerical simulation were in good agreement,which can provide significant references for damage evaluation and disaster forecasting in high geostress underground powerhouse caverns.

Characteristics of microseismic b-value associated with rock mass large deformation in underground powerhouse caverns at different stress levels

Rock mass large deformation in underground powerhouse caverns has been a severe hazard in hydropower engineering in Southwest China.During the development of rock mass large deformation,a sequence of fractures was generated that can be monitored using microseismic(MS)monitoring techniques.Two MS monitoring systems were established in two typical underground powerhouse caverns featuring distinct geostress levels.The MS b-values associated with rock mass large deformation and their temporal variation are analysed.The results showed that the MS bvalue in course of rock mass deformation was less than 1.0 in the underground powerhouse caverns at a high stress level while larger than 1.5 at a low stress level.Prior to the rock mass deformation,the MS b-values derived from both the high-stress and low-stress underground powerhouse caverns show an incremental decrease over 10%within 10 d.The results contribute to understanding the fracturing characteristics of MS sources associated with rock mass large deformation and provide a reference for early warning of rock mass large deformation in underground powerhouse caverns.

Integrated Inspection of QoM, QoP, and QoS for AOI Industries in Metaverses

With the rapid development of information technologies such as digital twin, extended reality, and blockchain,the hype around "metaverse" is increasing at astronomical speed. However, much attention has been paid to its entertainment and social functions. Considering the openness and interoperability of metaverses, the market of quality inspection promises explosive growth. In this paper, taking advantage of metaverses, we first propose the concept of Automated Quality Inspection(Auto QI), which performs integrated inspection covering the entire manufacturing process, including Quality of Materials, Quality of Manufacturing(Qo M), Quality of Products, Quality of Processes(Qo P), Quality of Systems, and Quality of Services(Qo S). Based on the scenarios engineering theory, we discuss how to perform interactions between metaverses and the physical world for virtual design instruction and physical validation feedback. Then we introduce a bottomup inspection device development workflow with productivity tools offered by metaverses, making development more effective and efficient than ever. As the core of quality inspection,we propose Quality Transformers to complete detection task,while federated learning is integrated to regulate data sharing.In summary, we point out the development directions of quality inspection under metaverse tide.

Tensile Strength Characteristics of GFRP Bars in Concrete Beams with Work Cracks under Sustained Loading and Severe Environments

To investigate the effect of different environmental conditions of GFRP bars in concrete beams with work cracks subjected to sustained loads, the beams were exposed in indoor, freeze/thaw cycles and immersed in alkaline solution at elevated temperature. The bars were carefully extracted from the beams and tested in order to evaluate residual tensile properties. The results show that the tensile strength decreased significantly in the highly aggressive conditions but not in the natural conditions. The effect of GFRP bars casting in concrete beams demonstrated approximately 2.5% decrease of tensile strength caused by pore water environment in concrete beams on basis of those of the original bars. The effect of sustained loading plus work cracks demonstrated about 10.5% tensile strength decrease on basis of those of the bars only casted in concrete beams. The effect of environments under sustained loading plus work cracks demonstrated about 17% tensile strength decrease caused by a saturated solution of Ca（OH）2 and 60-2 ℃ tap water （pH=12-13） and about 8% tensile strength decrease caused by freezing and thawing cycle （F/T）, both on basis of those of the bars of the indoor beams only under sustained loading plus work cracks. The results demonstrate the effects of the tensile strengths under different environmental conditions of GFRP bars in concrete beams with work cracks subjected to sustained loads.

Bending of small-scale Timoshenko beams based on the integral/differential nonlocal-micropolar elasticity theory: a finite element approach

A novel size-dependent model is developed herein to study the bending behavior of beam-type micro/nano-structures considering combined effects of nonlocality and micro-rotational degrees of freedom. To accomplish this aim, the micropolar theory is combined with the nonlocal elasticity. To consider the nonlocality, both integral (original) and differential formulations of Eringen’s nonlocal theory are considered. The beams are considered to be Timoshenko-type, and the governing equations are derived in the variational form through Hamilton’s principle. The relations are written in an appropriate matrix-vector representation that can be readily utilized in numerical approaches. A finite element (FE) approach is also proposed for the solution procedure. Parametric studies are conducted to show the simultaneous nonlocal and micropolar effects on the bending response of small-scale beams under different boundary conditions.

Bending of Euler-Bernoulli nanobeams based on the strain-driven and stress-driven nonlocal integral models: a numerical approach

Eringen's nonlocal elasticity theory is extensively employed for the analysis of nanostructures because it is able to capture nanoscale effects.Previous studies have revealed that using the differential form of the strain-driven version of this theory leads to paradoxical results in some cases,such as bending analysis of cantilevers,and recourse must be made to the integral version.In this article,a novel numerical approach is developed for the bending analysis of Euler-Bernoulli nanobeams in the context of strain-and stress-driven integral nonlocal models.This numerical approach is proposed for the direct solution to bypass the difficulties related to converting the integral governing equation into a differential equation.First,the governing equation is derived based on both strain-driven and stress-driven nonlocal models by means of the minimum total potential energy.Also,in each case,the governing equation is obtained in both strong and weak forms.To solve numerically the derived equations,matrix differential and integral operators are constructed based upon the finite difference technique and trapezoidal integration rule.It is shown that the proposed numerical approach can be efficiently applied to the strain-driven nonlocal model with the aim of resolving the mentioned paradoxes.Also,it is able to solve the problem based on the strain-driven model without inconsistencies of the application of this model that are reported in the literature.

Three-dimensional Expansion:In Suspension Culture of SD Rat's Osteoblasts in a Rotating Wall Vessel Bioreactor

Objective To study large-scale expansion of SD （Sprague-Dawley） rat＇s osteoblasts in suspension culture in a rotating wall vessel bioreactor （RWVB）. Methods The bioreactor rotation speeds were adjusted in the range of 0 to 20 rpm, which could provide low shear on the rnicrocarriers around 1 dyn/cm^2. The cells were isolated via sequential digestions of neonatal （less than 3 days old） SD rat calvaria. After the primary culture and several passages, the cells were seeded onto the microcarriers and cultivated in T-flask, spinner flask and RWVB respectively. During the culture period, the cells were counted and observed under the inverted microscope for morphology every 12 h. After 7 days, the cells were evaluated with scanning electron microscope （SEM） for histological examination of the aggregates. Also, the hematoxylin-eosin （HE） staining and alkaline phosphatase （ALP） staining were performed. Moreover, von-Kossa staining and Alizarin Red S staining were carded out for mineralized nodule formation. Results The results showed that in RWVB, the cells could be expanded by more than ten times and they presented better morphology and vitality and stronger ability to form bones. Conclusions The developed RWVB can provide the culture environment with a relatively low shear force and necessary three-dimensional （3D） interactions among cells and is suitable for osteopath expansion in vitro.

Electroencephalography studies of hypoxic ischemia in fetal and neonatal animal models

Alongside clinical achievements,experiments conducted on animal models (including primate or non-primate) have been effective in the understanding of various pathophysiological aspects of perinatal hypoxic/ ischemic encephalopathy (HIE).Due to the reasonably fair degree of flexibility with experiments,most of the research around HIE in the literature has been largely concerned with the neurodevelopmental outcome or how the frequency and duration of HI seizures could relate to the severity of perinatal brain injury,following HI insult.This survey concentrates on how EEG experimental studies using asphyxiated animal models (in rodents,piglets,sheep and non-human primate monkeys) provide a unique opportunity to examine from the exact time of HI event to help gain insights into HIE where human studies become difficult.

A Review of Technical Advances,Barriers,and Solutions in the Power to Hydrogen(P2H)Roadmap

Power to hydrogen(P2H)provides a promising solution to the geographic mismatch between sources of renewable energy and the market,due to its technological maturity,flexibility,and the availability of technical and economic data from a range of active demonstration projects.In this review,we aim to provide an overview of the status of P2H,analyze its technical barriers and solutions,and propose potential opportunities for future research and industrial demonstrations.We specifically focus on the transport of hydrogen via natural gas pipeline networks and end-user purification.Strong evidence shows that an addition of about 10%hydrogen into natural gas pipelines has negligible effects on the pipelines and utilization appliances,and may therefore extend the asset value of the pipelines after natural gas is depleted.To obtain pure hydrogen from hydrogen-enriched natural gas(HENG)mixtures,end-user separation is inevitable,and can be achieved through membranes,adsorption,and other promising separation technologies.However,novel materials with high selectivity and capacity will be the key to the development of industrial processes,and an integrated membrane-adsorption process may be considered in order to produce high-purity hydrogen from HENG.It is also worth investigating the feasibility of electrochemical separation(hydrogen pumping)at a large scale and its energy analysis.Cryogenics may only be feasible when liquefied natural gas(LNG)is one of the major products.A range of other technological and operational barriers and opportunities,such as water availability,byproduct(oxygen)utilization,and environmental impacts,are also discussed.This review will advance readers’understanding of P2H and foster the development of the hydrogen economy.

Incident flow effects on the performance of piezoelectric energy harvesters from galloping vibrations

In this paper, we investigate experimentally the concept of energy har- vesting from galloping oscillations with a focus on wake and turbulence effects. The .harvester is composed of a unimorph piezoelectric cantilever beam with a square cross-section tip mass. In one case, the harvester is placed in the wake of another galloping harvester with the objective of determining the wake effects on the response of the harvester. In the second case, meshes were placed upstream of the harvester with the objective of investigating the effects of upstream turbulence on the response of the harvester. The results show that both wake effects and up- stream turbulence significantly affect the response of the harvester. Depending on the spacing between the two squares and the opening size of the mesh, wake and upstream turbulence can positively enhance the level of the harvested power.