An Automatic Implementation of Oropharyngeal Swab Sampling for Diagnosing Respiratory Infectious Diseases via Soft Robotic End-Effectors

The most widely adopted method for diagnosing respiratory infectious diseases is to conduct polymerase chain reaction(PCR)assays on patients’respiratory specimens,which are collected through either nasal or oropharyngeal swabs.The manual swab sampling process poses a high risk to the examiner and may cause false-negative results owing to improper sampling.In this paper,we propose a pneumatically actuated soft end-effector specifically designed to achieve all of the tasks involved in swab sampling.The soft end-effector utilizes circumferential instability to ensure grasping stability,and exhibits several key properties,including high load-to-weight ratio,error tolerance,and variable swab-tip stiffness,leading to successful automatic robotic oropharyngeal swab sampling,from loosening and tightening the transport medium tube cap,holding the swab,and conducting sampling,to snapping off the swab tail and sterilizing itself.Using an industrial collaborative robotic arm,we integrated the soft end-effector,force sensor,camera,lights,and remote-control stick,and developed a robotic oropharyngeal swab sampling system.Using this swab sampling system,we conducted oropharyngeal swab-sampling tests on 20 volunteers.Our Digital PCR assay results(RNase P RNA gene absolute copy numbers for the samples)revealed that our system successfully collected sufficient numbers of cells from the pharyngeal wall for respiratory disease diagnosis.In summary,we have developed a pharyngeal swab-sampling system based on an“enveloping”soft actuator,studied the sampling process,and imple-mented whole-process robotic oropharyngeal swab-sampling.

Low-temperature activity and mechanism of WO_3-modified CeO_2-TiO_2 catalyst under NH_3-NO/NO_2 SCR conditions

The CeO2‐TiO2(CeTi)and CeO2/WO3‐TiO2(CeWTi)catalysts were prepared by a sol‐gel precipitation method and their NH3‐NO/NO2 selective catalytic reduction(SCR)performance was studied.N2O formation and effect of oxygen concentration on SCR performance over CeWTi catalyst were also investigated while varying the NO2/NOx ratio.Results indicate that fast SCR behavior of CeWTi catalyst has the best NH3‐NO/NO2 SCR performance due to the catalyst reoxidation rate by NO2 higher than by O2.Compared with CeTi catalyst,CeWTi catalyst exhibits higher de‐NOx performance under NH3‐NO/NO2 SCR conditions.As the CeTi and CeWTi catalysts exhibit similar redox property,addition of WO3 provides more acid sites which accelerate the reaction between NH4NO3 and NO to get a superior low‐temperature activity.Amount of N2O formation shows a peak at 250 oC mainly derived from NH4NO3 decomposition.

One-step fabrication superhydrophobic sand filter for capillary-driven separation of water-in-oil emulsions

The efficient separation of water-in-oil emulsion is of significance in environment and energy filed,and it has become a world-wide challenge.Herein,we have presented a one-step,facile and low-cost approach to prepare superhydrophobic sands for efficient separation of water-in-oil emulsion.The as-prepared sand layers possessed a water contact angle higher than 151°,demonstrating their superior superhydrophobic property.Besides,the as-prepared sand layers could separate water-in-emulsions with separation efficiency up to 99.7%,which is superior to both traditional and superwettable filtration membranes.The effect of thickness of sand layer on separation performance was also investigated.The results showed that the filtration flux decreased with the increased of filtration thickness while the separation efficiency increased.The as-prepared sand layer proposed by this study is a processing candidate for separating water-in-oil emulsion in practical industry.Additionally,the as-prepared superhydrophobic sand fabrication method also provides an alternative for desert water storage.

A novel UHMWPE composite with low friction coefficient for long-term ice sliding

Low friction ice sliding interfaces were critical for ski performance optimization.Traditional fluorinated ski waxes have attracted considerable attention for enhancing the hydrophobicity,anti-wearing,and oxidation resistance of ski–ice base.However,the toxicity and complexity of the waxing process limited batch manufacturing of low-cost and non-toxic ski–ice base,what is more,the wax covering on the base wore and failed during skiing due to the friction between ski and ice.Herein,we demonstrated a novel ultra-high molecular weight polyethylene(UHMWPE)composite that could maintain a low coefficient of friction(COF)with about 0.026 for at least 160 min when skiing on the ice.Microcapsule(MS)could release liquid(liquid paraffin(LP)).The released LP further enhanced the hydrophobicity of UHMWPE’s surfaces when friction occurred,which would maintain the stability and durability of the water film,and achieved superior and long-lasting friction resistance.Compared with other microcapsules with lower hydrophobic core,microcapsules with LP performed the best in reducing the friction of ski base from 0.126 to 0.024.Meanwhile,the COF of the surface kept at about 0.02 even after 12 rapid temperature changes.The presented UHMWPE composite of encapsulated liquids showed great potential and broad application owing to its simplicity and efficiency in winter sports.

Status and developmental trends in recombinant collagen preparation technology

Recombinant collagen is a pivotal topic in foundational biological research and epitomizes the application of critical bioengineer-ing technologies.These technological advancements have pro-found implications across diverse areas such as regenerative medicine,organ replacement,tissue engineering,cosmetics and more.Thus,recombinant collagen and its preparation methodologies rooted in genetically engineered celis mark pivotal milestones in medical product research.This article pro-vides a comprehensive overview of the current genetic engi-neering technologies and methods used in the production of recombinant collagen,as well as the conventional production process and gquality control detection methods for this material.Furthermore,the discussion extends to foresee the strides in physical transfection and magnetic control sorting studies,envisioning an enhanced preparation of recombinant collagen-seeded cells to further fuel recombinant collagen production.

Progress and prospect of technical and regulatory challenges on tissue-engineered cartilage as therapeutic combination product

Hyaline cartilage plays a critical role in maintaining joint function and pain.However,the lack of blood supply,nerves,and lymphatic vessels greatly limited the self-repair and regeneration of damaged cartilage,giving rise to various tricky issues in medicine.In the past 30 years,numerous treatment techniques and commercial products have been developed and practiced in the clinic for promoting defected cartilage repair and regeneration.Here,the current therapies and their relevant advantages and disadvantages will be summarized,particularly the tissue engineering strategies.Furthermore,the fabrication of tissue-engineered cartilage under research or in the clinic was discussed based on the traid of tissue engineering,that is the materials,seed cells,and bioactive factors.Finally,the commercialized cartilage repair products were listed and the regulatory issues and challenges of tissue-engineered cartilage repair products and clinical application would be reviewed.

Progress of marine biofouling and antifouling technologies

Adhesion of marine fouling organisms on artificial surfaces such as ship hulls causes many problems, including extra energy consumption, high maintenance costs, and increased corrosion. Therefore, marine antifouling is an important issue. In this review, physical and biochemical developments in the field of marine biofouling, which involves biofilm formation and macro-organism settlement, are discussed. The major antifouling technologies based on traditional chemical methods, biological methods, and physical methods are presented. The chemical methods include self-polishing types such as tributyltin (TBT) self-polishing co- polymer coatings, which despite its good performance has been banned since 2008 because of its serious environmental impact. Therefore, other methods have been encouraged. These include coatings with copper compounds and biocide boosters to replace the TBT coatings. Biological extracts of secreted metabolites and enzymes are anticipated to act as antifoulants. Physical methods such as modification of surface topography, hydrophobic properties, and charge potential have also been considered to prevent biofouling. In this review, most of the current antifouling technologies are discussed. It is proposed that the physical antifouling technologies will be the ultimate antifouling solution, because of their broad-spectrum effectiveness and zero toxicity.

Bionic Research on Fish Scales for Drag Reduction

To reduce friction drag with bionic method in a more feasible way, the surface microstructure of fish scales was analyzed attempting to reveal the biologic features responding to skin friction drag reduction. Then comparable bionic surface mimicking fish scales was fabricated through coating technology for drag reduction. The paint mixture was coated on a substrate through a self-developed spray-painting apparatus. The bionic surface with micron-scale caves formed spontaneously due to the interra- cial convection and deformation driven by interfacial tension gradient in the presence of solvent evaporation. Comparative experiments between bionic surface and smooth surface were performed in a water tunnel to evaluate the effect of bionic surface on drag reduction, and visible drag reduction efficiency was obtained. Numerical simulation results show that gas phase de- velops in solid-liquid interface of bionic surface with the effect of surface topography and partially replaces the solid-liquid shear force with gas-liquid shear force, hence reducing the skin friction drag effectively. Therefore, with remarkable drag re- duction performance and simple fabrication technology, the proposed drag reduction technique shows the promise for practical applications.

Hydrothermal and sulfur aging of CeTi/CeWTi catalysts for selective catalytic reduction of NOx with NH3

The CeO2-TiO2(CeTi)and CeO2/WO3-TiO2(CeWTi)catalysts were prepared by sol-gel method.The asprepared catalysts were hydrothermally treated at 760℃for 48 h in air containing 10 vol%H2O to obtain the hydrothermal aged catalysts.The sulfur aged catalysts were treated at 400℃with 100 ppm SO2,10%water vapor,air balance for 48 h and catalysts.The powder X-ray diffraction(XRD)and Raman results indicate that the crystallization of hydrothermal aged catalysts is more serious than sulfur aged catalysts.In addition,tungsten species can stabilize the CeTi catalyst from grain growth.According to the results of in situ diffuse reflectance infrared Fourier transform spectra(DRIFTS),temperatureprogrammed desorption of ammonia(NH3-TPD),H2 temperature-programmed reduction(H2-TPR)and ammonia oxidation,the aging process leads to loss of surface area,redox properties,surface acidities and surface ceria concentration,especially for the hyd rothermal aging.The NH3-NO/NO2 SCR perfo rmances of sulfur aged catalysts are better than that of hydrothermal aged catalysts.Compared with CeTi catalyst,the addition of tungsten inhibits the crystallization of catalyst.So that more acid sites and active sites are retained.This is also the reason why tungsten addition improves the NH3-NO/NO2 SCR performance of CeTi catalyst.

Underwater drag reduction by gas

Publications on underwater drag reduction by gas have been gathered in the present study.Experimental methods,results and conclusions from the publications have been discussed and analyzed.The stable existence of gas is a requirement for underwater drag reduction induced by slippage at the water-solid interface.A superhydrophobic surface can entrap gas in surface structures at the water-solid interface.However,many experimental results have exhibited that the entrapped gas can disappear,and the drag gradually increases until the loss of drag reduction with immersion time and underwater flow.Although some other surface structures were also experimented to hold the entrapped gas,from the analysis of thermodynamics and mechanics,it is difficult to prohibit the removal of entrapped gas in underwater surface structures.Therefore,it is essential to replenish a new gas supply for continued presence of gas at the interface for continued underwater drag reduction.Active gas supplement is an effective method for underwater drag reduction,however,that needs some specific equipment and additional energy to generate gas,which limits its practical application.Cavitation or supercavitation is a method for passive gas generation,but it is only adaptive to certain vehicles with high speed.Lately,even at low speed,the evaporation induced by liquid-gas-solid interface of a transverse microgrooved surface for continued gas supply has been discovered,which should be a promising method for practical application of underwater drag reduction by gas.