Development of biomedical hydrogels for rheumatoid arthritis treatment

Rheumatoid Arthritis(RA)is an autoimmune disorder that hinders the normal functioning of bones and joints and reduces the quality of human life.Every year,millions of people are diagnosed with RA worldwide,particularly among elderly individuals and women.Therefore,there is a global need to develop new biomaterials,medicines and therapeutic methods for treating RA.This will improve the Healthcare Access and Quality Index and also relieve administrative and financial burdens on healthcare service providers at a global scale.Hydrogels are soft and cross-linked polymeric materials that can store a chunk of fluids,drugs and biomolecules for hydration and therapeutic applications.Hydrogels are biocompatible and exhibit excellent mechanical properties,such as providing elastic cushions to articulating joints by mimicking the natural synovial fluid.Hence,hydrogels create a natural biological environment within the synovial cavity to reduce autoimmune reactions and friction.Hydrogels also lubricate the articulating joint surfaces to prevent degradation of synovial surfaces of bones and cartilage,thus exhibiting high potential for treating RA.This work reviews the progress in injectable and implantable hydrogels,synthesis methods,types of drugs,advantages and challenges.Additionally,it discusses the role of hydrogels in targeted drug delivery,mechanistic behaviour and tribological performance for RA treatment.

Enhancement of surface wettability via micro-and nanostructures by single point diamond turning

Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes. One of the strategies to tune surface wettability is modifying surface topography at micro-and nanoscales. In this research, periodic micro-and nanostructures were patterned on several polymer surfaces by ultra-precision single point diamond turning to investigate the relationships between surface topographies at the micro-and nanoscales and their surface wettability. This research revealed that single-point diamond turning could be used to enhance the wettability of a variety of polymers, including polyvinyl chloride(PVC), polyethylene 1000(PE1000), polypropylene copolymer(PP) and polytetrafluoroethylene(PFTE), which cannot be processed by conventional semiconductor-based manufacturing processes. Materials exhibiting common wettability properties(θ≈ 90°) changed to exhibit "superhydrophobic" behavior(θ > 150°). Compared with the size of the structures, the aspect ratio of the void space between micro-and nanostructures has a strong impact on surface wettability.

Constraint and Mobility Change Analysis of Rubik’s Cube-inspired Reconfigurable Joints and Corresponding Parallel Mechanisms

The current research of reconfigurable parallel mechanism mainly focuses on the construction of reconfigurable joints.Compared with the method of changing the mobility by physical locking joints,the geometric constraint has good controllability,and the constructed parallel mechanism has more configurations and wider application range.This paper presents a reconfigurable axis(rA)joint inspired and evolved from Rubik’s Cubes,which have a unique feature of geometric and physical constraint of axes of joint.The effectiveness of the rA joint in the construction of the limb is analyzed,resulting in a change in mobility and topology of the parallel mechanism.The rA joint makes the angle among the three axes inside the groove changed arbitrarily.This change in mobility is completed by the case illustrated by a 3(rA)P(rA)reconfigurable parallel mechanism having variable mobility from 1 to 6 and having various special configurations including pure translations,pure rotations.The underlying principle of the metamorphosis of this rA joint is shown by investigating the dependence of the corresponding screw system comprising of line vectors,leading to evolution of the rA joint from two types of spherical joints to three types of variable Hooke joints and one revolute joint.The reconfigurable parallel mechanism alters its topology by rotating or locking the axis of rA joint to turn all limbs into different phases.The prototype of reconfigurable parallel mechanism is manufactured and all configurations are enumerated to verify the validity of the theoretical method by physical experiments.

Identification of Contaminant Source Characteristics and Monitoring Network Design in Groundwater Aquifers: An Overview

The groundwater system is often polluted by different sources of contamination where the sources are difficult to detect. The presence of contamination in groundwater poses significant challenges to its delineation and quantification. The remediation of a contaminated site requires an optimal decision making system to identify the pollutant source characteristics accurately and efficiently. The source characteristics are generally identified using contaminant concentration measurements from arbitrary or planned monitoring locations. To effectively characterize the sources of pollution, the monitoring locations should be selected appropriately. An efficient monitoring network will result in satisfactory characterization of contaminant sources. On the other hand, an appropriate design of monitoring network requires reliable source characteristics. A coupled iterative sequential source identification and dynamic monitoring network design, improves substantially the accuracy of source identification model. This paper reviews different source identification and monitoring network design methods in groundwater contaminant sites. Further, the models for sequential integration of these two models are presented. The effective integration of source identification and dedicated monitoring network design models, distributed sources, parameter uncertainty, and pollutant geo-chemistry are some of the issues which need to be addressed in efficient, accurate and widely applicable methodologies for identification of unknown pollutant sources in contaminated aquifers.

Machine learning enabled identification and real-time prediction of living plants’ stress using terahertz waves

Considering the ongoing climate transformations, the appropriate and reliable phenotyping information of plant leaves is quite significant for early detection of disease, yield improvement. In real-life digital agricultural environment, the real-time prediction and identification of living plants leaves has immensely grown in recent years. Hence, cost-effective and automated and timely detection of plans species is vital for sustainable agriculture. This paper presents a novel, non-invasive method aiming to establish a feasible, and viable technique for the precise identification and observation of altering behaviour of plants species at cellular level for four consecutive days by integrating machine learning (ML) and THz with a swissto12 materials characterization kit (MCK) in the frequency range of 0.75 to 1.1 THz. For this purpose, measurements observations data of seven various living plants leaves were determined and incorporate three different ML algorithms such as random forest (RF), support vector machine, (SVM), and K-nearest neighbour (KNN). The results demonstrated that RF exhibited higher accuracy of 98.87% followed by KNN and SVM with an accuracy of 94.64% and 89.67%, respectively, for precise detection of different leaves by observing their morphological features. In addition, RF outperformed other classifiers for determination of water-stressed leaves and having an accuracy of 99.42%. It is envisioned that proposed study can be proven beneficial and vital in digital agriculture technology for the timely detection of plants species to significantly help in mitigate yield and economic losses and improve crops quality.

Standing on the Shoulders of Giants： A Brief Note from the Perspective of Kinematics

Kinematics has evolved with and contributed significantly to human demands. For example, slider-crank mechanisms have been widely used in engines since the industrial revolution. Additionally, constant-velocity shaft couplings have been developed to meet the needs of the automobile industry since the 1920＇s. With the development of robots, robot kinematics has been one of the research focuses in Kinematics since the 1970＇s.

Design of on-demand wireless capsule endoscope

An on-demand wireless capsule endoscope with fulldigital and bidirectional communication is presented,aiming at fulfilling the requirements of micromation and micropower consumption of modern wireless endoscope.The proposed multifunctional operation and unique radio transmission system cuts down the power consumption efficiently and on-demand bidirectional communication in vitro improves the detection rate of focus.Meanwhile,gray dilatation is introduced in a bit plane that optimizes the distortion rate in the process of image recording and transmission.

Reconciling ＂Micro＂ and ＂Macro＂ through Meso-Science

20世纪90年代,笔者受邀对中国科学院的李静海教授和郭慕孙教授的文章进行评审,其中阐述了能量最小多尺度(EMMS)的概念。EMMS理论在各种会议上已被充分讨论过,该理论也是李的博士论文的研究对象。当时看到这篇文章,我的第一印象就是这是一个很有意思的概念,但也不过是一个阐述考究的学术精品而已。该理论阐述严谨。

Extracts of the seaweed Bifurcaria bifurcata display antifungal activity against human dermatophyte fungi

Bifurcaria bifurcata is a seaweed of the Order Fucales(Ochrophyta,Phaeophyceae)that can be found all year round along the Portuguese Atlantic shore.Although it is considered edible in some countries,its biotechnological potential has not yet been assessed in detail and here we report its antimicrobial potential against human dermatophyte fungi.Three samples were harvested from Baleal Island(Peniche,Portugal)harvested in winter(BbPe);from Aguda Beach(Arcozelo,Vila Nova de Gaia,Portugal),harvested in autumn(BbAg)and a sample obtained by culturing the Aguda sample under laboratory conditions(BbLC).A broth macrodilution assay was applied to determine the MIC(minimum inhibitory concentration)and MLC(minimum lethal concentration)of the B.bifurcata extracts.Results show that the BbPe MeOH extracts were the most effective and had higher antifungal activity against all the tested dermatophyte strains than the BbLC and BaAg extracts[Epidermophyton floccosum FF9(100–200μg/mL MIC;200μg/mL MLC),Microsporum canis FF1(400μg/mL MIC;≥400μg/mL MLC),Trichophyton mentagrophytes FF7(100μg/mL MIC;>800μg/mL MLC),M.gypseum CECT 2908(800μg/mL MIC;≥800μg/mL MLC),T.mentagrophytes var.interdigitale CECT 2958(800μg/mL MIC;≥800μg/mL MLC),T.rubrum CECT 2794(200μg/mL MIC;≥400μg/mL MLC)].In fact,only E.floccosum FF9 was sensitive to BbAg and BbLC MeOH extracts.To our knowledge,this is the first report of antifungal activity of B.bifurcata against human dermatophyte fungi.

The effect of Si content on the martensitic transformation temperature of Ni_(55.5)Fe_(18)Ga_(26.5-x)Si_x alloys

This paper investigates the effects of substitution of Si for Ga on the martensitic transformation behaviours in Ni-Fe-Ga alloys by using optical metallographic microscope and differential scanning calorimetry （DSC） methods. The structure type of Ni55.5Fe18Ga26.5-xSix alloys is determined by x-ray diffraction （XRD）, and the XRD patterns show the microstructure of Ni-Fe-Ga-Si alloys transformed from body-centred tetragonal martensite （with Si content x = 0） to body-centred cubic austenite （with x = 2） at room temperature. The martensitic transformation temperatures of the Ni55.sFelsGa26.5-xSi~ alloys decrease almost linearly with increasing Si content in the Si content range of x _~ 3. Thermal treatment also plays an important role on martensitic transformation temperatures in the Ni-Fe-Ga^Si alloy. The valence electronic concentrations, size factor, L21 degree of order and strength of parent phase influence the martensitic transformation temperatures of the Ni-Fe-Ga-Si alloys. An understanding of the relationship between martensitic transformation temperatures and Si content will be significant for designing an appropriate Ni-Fe-Ga-Si alloy for a specific application at a given temperature.

Characterization of Groundwater Pollution Sources with Unknown Release Time History

Characterizations of unknown groundwater pollution sources in terms of source location, source flux release history and sources activity initiation times, from sparse observation concentration measurements are a challenging task. Optimization-based methods are often applied to solve groundwater pollution source characterization problem. These methods are effective only when the starting times of activity of the sources are precisely known, or the possible time window within which the sources activity actually start is known with a fair degree of certainty. However, in real life scenarios, the starting time of the activity of the sources is either unknown or can lie anywhere within a time window of years or decades. Absence of any prior information about the span of time window, within which the sources become active, makes existing source identification methodologies inefficient. As an alternative, an optimization-based source identification model is proposed, to simultaneously estimate source flux release history and sources activity initiation times. The method considers source flux release history and sources activity initiation times as explicit decision variables, optimally estimated by the decision model. Performance of the developed methodology is evaluated for an illustrative study area having multiple sources with different source activity initiation times, missing observation data and transient flow conditions. These evaluation results demonstrate the potential applicability of the proposed methodology and its capability to correctly estimate the unknown source flux releasing history and sources activity initiation times.

Kinetic parameter estimation for cooling crystallization process based on cell average technique and automatic differentiation

In this paper,a cell average technique(CAT)based parameter estimation method is proposed for cooling crystallization involved with particle growth,aggregation and breakage,by establishing a more efficient and accurate solution in terms of the automatic differentiation(AD)algorithm.To overcome the deficiency of CAT that demands high computation cost for implementation,a set of ordinary differential equations(ODEs)entailed from CAT based discretized population balance equation(PBE)are solved by using the AD based high-order Taylor expansion.Moreover,an AD based trust-region reflective(TRR)algorithm and another interior-point(IP)algorithm are established for estimating the kinetic parameters associated with particle growth,aggregation and breakage.As a result,the estimation accuracy can be further improved while the computation cost can be significantly reduced,compared to the existing algorithms.Benchmark examples from the literature are used to illustrate the accuracy and efficiency of the AD-based CAT,TRR and IP algorithms in comparison with the existing algorithms.Moreover,seeded batch cooling crystallization experiments ofβform L-glutamic acid are performed to validate the proposed method.

Encapsulating the Role of Solution Response Space Roughness on Global Optimal Solution: Application in Identification of Unknown Groundwater Pollution Sources

A major challenge of any optimization problem is to find the global optimum solution. In a multi-dimensional solution space which is highly non-linear, often the optimization algorithm gets trapped around some local optima. Optimal Identification of unknown groundwater pollution sources poses similar challenges. Optimization based methodology is often applied to identify the unknown source characteristics such as location and flux release history over time, in a polluted aquifer. Optimization based models for identification of these characteristics of unknown ground-water pollution sources rely on comparing the simulated effects of candidate solutions to the observed effects in terms of pollutant concentration at specified sparse spatiotemporal locations. The optimization model minimizes the difference between the observed pollutant concentration measurements and simulated pollutant concentration measurements. This essentially constitutes the objective function of the optimization model. However, the mathematical formulation of the objective function can significantly affect the accuracy of the results by altering the response contour of the solution space. In this study, two separate mathematical formulations of the objective function are compared for accuracy, by incorporating different scenarios of unknown groundwater pollution source identification problem. Simulated Annealing (SA) is used as the solution algorithm for the optimization model. Different mathematical formulations of the objective function for minimizing the difference between the observed and simulated pollutant concentration measurements show different levels of accuracy in source identification results. These evaluation results demonstrate the impact of objective function formulation on the optimal identification, and provide a basis for choosing an appropriate mathematical formulation for unknown pollution source identification in contaminated aquifers.

Optimal Unknown Pollution Source Characterization in a Contaminated Groundwater Aquifer—Evaluation of a Developed Dedicated Software Tool

Precise identification of the pollutant source characteristics is the first step for designing an effective groundwater contamination remediation strategy. In this study a linked simulation-optimization based methodology is utilized for identification of unknown groundwater pollution sources in a real life contaminated aquifer in New South Wales, Australia where the source locations and source flux release history are the explicit unknown variables. The methodology is applied utilizing an in house software package GWSID developed at James Cook University for optimal determination of the unknown source characteristics. The methodology incorporates linked simulation optimization approach and utilizes simulated Algorithm as an evolutionary optimization algorithm. The performance evaluation results show practical utility of the methodology and of the associated developed computers software in identifying the unknown source characteristics.

Numerical analysis of the performance of a three-bladed vertical-axis turbine with active pitch control using a coupled unsteady Reynolds-averaged Navier-Stokes and actuator line model

In this paper,we present a numerical model of a vertical-axis turbine(VAT)with active-pitch torque control.The model is based upon the Wind and Tidal Turbine Embedded Simulator(WATTES)and WATTES-V turbine realisations in conjunction with the actuator line method(ALM),and uses OpenFOAM to solve the unsteady Reynolds-averaged Navier-Stokes(URANS)equations with two-equation k-εturbulence closure.Our novel pitch-controlled system is based on an even pressure drop across the entire rotor to mitigate against dynamic stall at low tip speed ratio.The numerical model is validated against experimental measurements and alternative numerical predictions of the hydrodynamic performance of a 1:6 scale UNH-RM2 hydrokinetic turbine.Simulations deploying the variable pitch mechanism exhibit improved turbine performance compared to measured data and fixed zero-pitch model predictions.Near-wake characteristics are investigated by examining the vorticity distribution near the turbine.The pitch-controlled system is demonstrated to theoretically decrease turbulence generated by turbine rotations,mitigate the intensity of vortex shedding and size of detached vortices,and significantly enhance the performance of a vertical-axis hydrokinetic turbine for rated tip-speed ratios.

A review on the mechanisms of low salinity water/surfactant/nanoparticles and the potential synergistic application for c-EOR

Chemical enhanced oil recovery(c-EOR)is a conventional and promising strategy to recover oil from reservoir techniques such as low salinity water flooding(LSWF),surfactant flooding,alkaline flooding,polymers flooding,and nanofluid flooding.The use of various types of chemical materials for c-EOR method has recently attracted the attention of the oil and gas industry.The primary objective of this review work is to explore the synergy of low salinity water/surfactant/nanoparticle flooding for effective c-EOR method and investigate the mechanism behind these methods.The advantages of combining these chemical materials for c-EOR methods is also reviewed.Challenges and limitations of this synergy and their economic feasibility for additional oil recovery and potential return on investment are reviewed.Nanoparticles have been successfully used in various applications in several industries and have also shown good application for EOR in terms of wettability alteration.LSWF contributes to wettability alteration,while surfactant contributes to wettability alteration and interfacial tension(IFT)reduction.However,fines migration caused by LSWF and nanoparticle agglomeration can cause formation damage,while excessive surfactant adsorption can lead to cost overrun on surfactant use.Understanding the characteristics of reservoir formation mineralogy and appropriate nanoparticle type,size,and concentration can be used to resolve this challenges.The synergy of LSWF and nanoparticles in alkaline medium can serve as sacrificial agent to reduce excessive surfactant loss.Therefore,the appropriate synergistic formulation of LSFW/surfactant/nanoparticle can improve additional oil recovery and support return on investment for c-EOR projects.

Ethics in Engineering and the Role of Responsible Technology

The idea of writing an Editorial on Responsible Technology sprung from the plenary lecture that I gave at the at The First International Conference on Energy and AI in Tianjin,China,where this Journal was launched.It was January 2020 and it was only a few weeks before a major shock hit the world:nobody could have predicted the approach of a pandemic that would affect the lives of every single person in the world.Has the pandemic changed what I wanted to say in my Editorial?

Biped Walking Robot Based on a 2-UPU+2-UU Parallel Mechanism

Existing biped robots mainly fall into two categories： robots with left and right feet and robots with upper and lower feet. The load carrying capability of a biped robot is quite limited since the two feet of a walking robot supports the robot alternatively during walking. To improve the load carrying capability, a novel biped walking robot is proposed based on a 2-UPU＋2-UU parallel mechanism. The biped walking robot is composed of two identical platforms（feet） and four limbs, including two UPU（universal-prismatic-universal serial chain） limbs and two UU limbs. To enhance its terrain adaptability like articulated vehicles, the two feet of the biped walking robot are designed as two vehicles in detail. The conditions that the geometric parameters of the feet must satisfy are discussed. The degrees-of-freedom of the mechanism is analyzed by using screw theory. Gait analysis, kinematic analysis and stability analysis of the mechanism are carried out to verify the structural design parameters. The simulation results validate the feasibility of walking on rugged terrain. Experiments with a physical prototype show that the novel biped walking robot can walk stably on smooth terrain. Due to its unique feet design and high stiffness, the biped walking robot may adapt to rugged terrain and is suitable for load-carrying.

Simulation and evaluation of the water purification function of Zhalong Wetland based on a combined water quantity-quality model

The water purification function of natural wetland systems is widely recognized,but rarely studied or scientifically evaluated.Extensive studies have been carried out by various international wetland research communities to quantify the water quality improvement ability of the natural wetlands,in order to maintain such ability and wetland ecological health.This study aims to evaluate the purification function of Zhalong Wetland in China for removing total nitrogen(TN) and phosphorus(TP),based on ex-situ experiments and the development of a combined water quantity-quality model.Experiments and model predictions were carried out with different input TP and TN concentrations.Statistical analyses demonstrated that the relative errors between model simulations and experimental observations for TN and TP were 8.6% and 12.4%,respectively.With water retention time being maintained at 90 d,the removal rate of these pollutants could not reach the required Grade V standards,if the inflow TN concentration was over 42 mg L-1,or the input TP concentration was over 14 mg L-1.The simulation results also demonstrated that,even with Grade V quality standard compliance,when the water inflow from surrounding industries and agriculture lands into Zhalong Wetland reaches 0.3×10 8 m 3 a-1,the maximum TN and TP loads that the reserve can cope with are 1.26×10 3 t a-1 and 0.42×10 3 t a-1,respectively.Overall,this study has produced a significant amount of information that can be used for the protection of water quality and ecological health of Zhalong Wetland.

Cuttlebone： Characterisation, Application and Development of Biomimetic Materials

Cuttlebone signifies a special class of ultra-lightweight cellular natural material possessing unique chemical, mechanical and structural properties, which have drawn considerable attention in the literature. The aim of this paper is to better understand the mechanical and biological roles of cuttlebone. First, the existing literature concerning the characterisation and potential applications inspired by this remarkable biomaterial is critiqued. Second, the finite element-based homogenisation method is used to verify that morphological variations within individual cuttlebone samples have minimal impact on the effective me- chanical properties. This finding agrees with existing literature, which suggests that cuttlebone strength is dictated by the cut- tlefish habitation depth. Subsequently, this homogenisation approach is further developed to characterise the effective me- chanical bulk modulus and biofluidic permeability that cuttlebone provides, thereby quanti lying its mechanical and transporting functionalities to inspire bionic design of structures and materials for more extensive applications. Finally, a brief rationale for the need to design a biomimetic material inspired by the cuttlebone microstructure is provided, based on the preceding inves- tigation.