A general comparison between tokamak and stellarator plasmas

This paper generally compares the essential features between tokamaks and stellarators,based on previous review work individually made by authors on several specific topics,such as theories,bulk plasma transport and edge divertor physics,along with some recent results.It aims at summarizing the main results and conclusions with regard to the advantages and disadvantages in these two types of magnetic fusion devices.The comparison includes basic magnetic configurations,magnetohydrodynamic(MHD)instabilities,operational limits and disruptions,neoclassical and turbulent transport,confinement scaling and isotopic effects,plasma rotation,and edge and divertor physics.Finally,a concept of quasi-symmetric stellarators is briefly referred along with a comparison of future application for fusion reactors.

Oral uptake and persistence of the FnAb-8 protein characterized by in situ radio-labeling and PET/CT imaging

The absorption of peptides and proteins delivered orally is minimum because of the intestine epithelial barrier.There are few known active transport mechanisms for macromolecules including the neonatal Fc Receptor(FcRn)for the absorption and secretion of IgGs in infant and adult intestine.We had previously described the FnAb-8 protein that could bind to h FcRn tightly at pH 6.0 but barely at pH 7.4.In this study,we examined its uptake,biodistribution and pharmacokinetics after peroral administration in both wild-type and human FcRn transgenic(Tg)mice.FnAb-8 was modified to contain trans-cyclooctene(TCO)which could interact with18 F labeled tetrazine in situ via the bioorthogonal inverseelectron-demand Diels-Alder reaction.We showed that FnAb-8 had a tendency to distribute and persist in the Tg mice intestine for an extended duration of time.It could also be absorbed into the circulation and distributed systemically over a long period of time up to 172 h.The improvement in oral uptake and concentration in the intestine tissue may be valuable for designing oral delivery of biopharmaceuticals,especially for diseases involving the gastric intestinal tissue.

The distribution and cell uptake of ApoA1 modified lipid carriers of siRNA in mouse liver in vivo

Fluorescence labeled small interfering RNAs(siRNAs)were loaded into lipopolyplexes modified with ApoA1(named as rHDL)and administered by intravenous injection.The biodistribution with time of these lipopolyplexes inside the liver and among various cell types was followed using tissue sections by Confocal fluorescence microscopy.At about 0.5 h after tail vein injection at a dose of 0.408 mg/kg,very few fluorescence signals were found in the liver.But then the signals could be seen to accumulate inside hepatocytes as discrete spots and diffused signals at around 2e4 h after injection.Such a distribution and uptake pattern was significantly different from what were observed using the commercial agent Invivofectamine
2.0 or DOTAP lipoplexes as the carriers.The differences indicated different mechanisms concerning the in vivo behavior of these carriers.The rHDL carrier system we developed was able to deliver siRNA specifically into hepatocytes while avoiding the uptake by REM cells especially the Kupffer cells.With it’s low toxicity and off target effect,it may be suitable to be developed as a hepatocyte targeting delivery system for siRNA.

First-principles study on the mechanical properties and thermodynamic properties of Mo-Ta alloys

The mechanical properties,thermodynamic properties and electronic structure of Mo1-xTax(Mo-Ta)alloys(x=0,0.0625,0.125,0.25,0.3125,0.5 and 1)were calculated by using firstprinciples.The electronic structure of Mo-Ta alloys was analysed by the projected density of states(PDOS).The low temperature heat capacity was estimated by Fermi energy and Debye temperature.It is shown that the formation enthalpy will decrease with the increase of Ta content,and the cohesive energy will increase with the increase of the Ta content.On the other hand,the addition of Ta atoms will reduce the strength and improve the ductility of Mo-Ta alloys,the Debye temperature will decrease and the low temperature heat capacity will be improved with the increase of the Ta content.All these results will be useful for the research of new plasma grid(PG)materials,which is mainly used in neutral beam injection(NBI)systems to produce negative hydrogen ions.

A NOTE ON g-CONCAVE FUNCTION

An equivalent condition is derived for g-concave function defined by (static) g-expectation. Several extensions including quadratic generators and (g,h)-concavity are also considered.

Multi-scale interaction between tearing modes and micro-turbulence in the HL-2A plasmas

The influence of m/n=2/1(m and n are poloidal and toroidal mode numbers)tearing modes on plasma perpendicular flows and micro-fluctuations has been investigated in HL-2A neutral beam injection heated L-mode plasmas.It is found that the local perpendicular rotation velocity and turbulence energy are modulated by the alternation between the island X-point and O-point of the naturally rotating tearing modes.Cross-correlation analysis indicates that the modulation of density fluctuations by the tearing mode is not only limited to the island region,but also occurs in the edge region near the last closed flux surface.The turbulence exhibits distinct spectral characteristics inside and outside the island region.In addition,it is observed that the particle flux near the strike point is also significantly impacted by the tearing modes.The experimental evidence reveals that there are strong core-edge interactions between the core tearing modes and the edge transport.

Impact of the mass isotope on plasma confinement and transport properties in the HL-2A tokamak

The impact of the mass isotope on plasma conflnement and transport properties has been investigated in Ohmically-heated hydrogen and deuterium plasmas in the HL-2 A tokamak.Experimental results show that under similar discharge parameters the deuterium plasma has better conflnement and lower turbulent transport than the hydrogen one,and concomitantly,it is found that the magnitude of geodesic acoustic mode zonal flows,the tilting angle of the Reynolds stress tensor and the turbulence correlation lengths are all larger in the edge region of the deuterium plasma.The results provide direct experimental evidence on the importance of the nonlinear energy coupling between ambient turbulence and zonal flows for governing the isotope effects in fusion plasmas.

Boron-doped microporous nano carbon as cathode material for high-performance Li-S batteries

In this study, a boron-doped microporous carbon （BMC）/sulfur nanocomposite is synthesized and applied as a novel cathode material for advanced Li-S batteries. The cell with this cathode exhibits an ultrahigh cycling stability and rate capability. After activation, a capacity of 749.5 mAh/g was obtained on the 54t＂ cycle at a discharge current of 3.2 A/g. After 500 cycles, capacity of 561.8 mAh/g remained （74.96% retention）, with only a very small average capacity decay of 0.056%. The excellent reversibility and stability of the novel sulfur cathode can be attributed to the ability of the boron-doped microporous carbon host to both physically confine polysulfides and chemically bind these species on the host surface. Theoretical calculations confirm that boron-doped carbon is capable of significantly stronger interactions with the polysulfide species than undoped carbon, most likely as a result of the lower electronegativity of boron. We believe that this doping strategy can be extended to other metal-air batteries and fuel cells, and that it has promising potential for many different applications.

Reimaging biological barriers affecting distribution and extravasation of PEG/peptidemodified liposomes in xenograft SMMC7721 tumor

Liposomes,as one of the most successful nanotherapeutics,have a major impact on many biomedical areas.In this study,we performed laser scanning confocal microscope(LSCM)and immunohistochemistry(IHC)assays to investigate the intra-tumor transport and antitumor mechanism of GE11 peptideconjugated active targeting liposomes(GE11-TLs)in SMMC7721 xenograft model.According to classification of individual cell types in high resolution images,biodistribution of macrophages,tumor cells,cells with high epidermal growth factor receptor(EGFR)expres sion and interstitial matrix in tumor microenvironment,in addition,their impacts on intra-tumor penetration of GE11-TLs were estimated.Type I collagen fibers and macrophage flooded in the whole SMMC7721 tumor xenografts.Tumor angiogenesis was of great heterogeneity from the periphery to the center region.However,the receptor-binding site barriers were supposed to be the leading cause of poor penetration of GE11-TLs.We anticipate these images can give a deep reconsideration for rational design of target nanoparticles for overcoming biological barriers to drag delivery.