Supersonic boundary layer transition induced by self-sustaining dual jets

To promote high-speed boundary layer transition,this paper proposes an active self-sustaining dual jets(SDJ)actuator utilizing the energy of supersonic mainflow.Employing the nanoparticle-based planar laser scattering(NPLS),supersonic flat-plate boundary layer transition induced by SDJ is experimentally investigated in an Ma-2.95 low-turbulence wind tunnel.Streamwise and spanwise NPLS images are obtained to analyze fine flow structures of the whole transition process.The results reveal the transition control mechanisms that on the one hand,the jet-induced shear layer produces unstable Kelvin–Helmholtz instabilities in the wake flow,on the other hand,the jets also generates an adverse pressure gradient in the boundary layer and induce unstable streak structures,which gradually break down into turbulence downstream.The paper provides a new method for transition control of high-speed boundary layer,and have prospect both in theory and engineering application.

Effect of physicochemical properties on in vivo fate of nanoparticle-based cancer immunotherapies

Current advances of immunotherapy have greatly changed the way of cancer treatment.At the same time,a great number of nanoparticle-based cancer immunotherapies(NBCIs)have also been explored to elicit potent immune responses against tumors.However,few NBCIs are nearly in the clinical trial which is mainly ascribed to a lack understanding of in vivo fate of nanoparticles(NPs)for cancer immunotherapy.NPs for cancer immunotherapy mainly target the immune organs or immune cells to enable effcient antitumor immune responses.The physicochemical properties of NPs including size,shape,elasticity and surface properties directly affect their interaction with immune systems as well as their in vivo fate and therapeutic effect.Hence,systematic analysis of the physicochemical properties and their effect on in vivo fate is urgently needed.In this review,we frst recapitulate the fundamentals for the in vivo fate of NBCIs including physio-anatomical features of lymphatic system and strategies to modulate immune responses.Moreover,we highlight the effect of physicochemical properties on their in vivo fate including lymph nodes(LNs)drainage,cellular uptake and intracellular transfer.Challenges and opportunities for rational design of NPs for cancer immunotherapy are also discussed in detail.

Performance of water-based drilling fluids for deepwater and hydrate reservoirs:Designing and modelling studies

In deepwater drilling,the properties of water-based drilling fluids change remarkably due to low temperature and high pressure,which have a significant effect on lost circulation,wellbore instability and the window between pore pressure and fracturing pressure.The present work investigates the influence of low temperature and high pressure on polymer and nanoparticle(boron nitride(BN))based drilling fluids with an aim to improve their rheological properties and fluid loss control.The amplitude and frequency sweep tests were conducted to understand the viscoelastic nature of the samples.The amplitude sweep tests confirmed the structural stability of the designed fluid within the studied sweep frequency.The study reveals that storage modulus(G')and loss modulus(G")of the samples are enhanced with increasing concentration of BN nanoparticles.Their viscoelastic range also increases due to the intermolecular interaction within the structure of the fluid in the presence of the nanoparticles.Within the linear viscoelastic range(LVER),all the samples show the dominance of elastic modulus than viscous modulus which delineates the solid-like behaviour.The results of rheological tests of drilling fluid containing BN nanoparticles indicate a significant reduction in plastic viscosity(PV),yield point(YP)and apparent viscosity(AV).The rheological studies conducted at different temperatures(from 10℃to-5℃)and pressures(from 7.8 MPa toll MPa)reveal the minimum effect of pressure and temperature on the rheology of samples,which are desirable for their applications in hydrate and deepwater drilling.The filtration loss experiments conducted at 30℃and 0.69 MPa show a large reduction in fluid loss volume(60.6%)and filter cake thickness(90%)for the sample with 0.4 wt%BN nano particles compared to that of the sample without nanoparticles.The filter cake permeability is also in the favourable range with0.008 mD which shows a 94%reduction compared to the sample without nanoparticles.A regression model was developed to mathematically describe the experimental results,which demonstrates a good fitting with the statistical data of fluid loss volume,thickness and permeability of the filter cake.

RNA-based nanomedicines and their clinical applications

RNA-based nanomedicines encompass a range of therapeutic approaches that utilize RNA molecules or molecules that target RNAs for the treatment or prevention of diseases.These include antisense oligonucleotides(ASOs),small interfering RNAs(siRNAs),endogenous microRNAs(miRNAs),messenger RNAs(mRNAs),clustered regularly interspersed short palindromic repeats-associated protein 9(CRISPR/Cas9),single guide RNAs(sgRNAs),as well as RNA aptamers.These therapeutic agents exert their effects through various mechanisms such as gene inhibition,addition,replacement,and editing.The advancement of RNA biology and the field of RNA therapy has paved the way for the development and utilization of RNA-based nanomedicine in human healthcare.One remarkable example of RNA-based nanomedicine is the mRNA-based vaccines including mRNA-1273(Moderna)and BNT162b2(Pfizer/BioNTech)that have been successfully employed in response to the coronavirus disease 2019(COVID-19)pandemic.This review aims to highlight the advantages of RNA-based nanomedicines,provides an overview of significant developments in delivery systems,elucidates the molecular mechanisms of action underlying RNA-based nanomedicines,and discusses their clinical applications.Additionally,the review will address the existing challenges and innovations in delivery platforms while exploring the future possibilities for these promising RNA-based nanomedicines.

Imaging of the Space-time Structure of a Vortex Generator in Supersonic Flow

The fine space-time structure of a vortex generator （VG） in supersonic flow is studied with the nanoparticle-based planar laser scattering （NPLS） method in a quiet supersonic wind tunnel. The fine coherent structure at the symmetrical plane of the flow field around the VG is imaged with NPLS. The spatial structure and temporal evolution characteristics of the vortical structure are analyzed, which demonstrate periodic evolution and similar geometry, and the characteristics of rapid movement and slow change. Because the NPLS system yields the flow images at high temporal and spatial resolutions, from these images the position of a large scale structure can be extracted precisely. The position and velocity of the large scale structures can be evaluated with edge detection and correlation algorithms. The shocklet structures induced by vortices are imaged, from which the generation and development of shocklets are discussed in this paper.

Mineral iron based self-assembling: bridging the small molecular drugs and transformative application

The nanoparticle-based treatment and diagnosis of cancer remain challenging in clinical translation, mainly due to the hurdles that can be associated with the development of targeted delivery, biological side effects, poor drug loading efficiency (DLE), and instability and so on [1,2].

Multi-resolution Analysis of Density Fluctuation of Coherent Structures About Supersonic Flow over VG

The density field around a vortex generator （VG） in supersonic flow is studied with a nanoparticle-based planar laser scattering （NPLS） method. Based on the calibration, i.e., the density distribution of the supersonic flow around a wedge, the density field of a supersonic VG is measured. According to movement characteristics of coherent structure in VG’s flow fields and the basic concepts of wavelet, the density fluctuating signals and multi-resolution characteristics of density field images are studied. The multi-resolution characteristics of density fluctuation can be analyzed with wavelet transformation of NPLS images. The wavelet approximate coefficients of density fluctuating signals exhibit their characteristics at different scales, and the corresponding detail coefficients show the difference of diverse layer smooth approximation in some way. Based on 2D wavelet decomposition and reconstruction of density field images, the approximate and detail signals at different scales are studied, and the coherent structures at different scales are extracted and analyzed.