Aptamer-functionalized Ti3C2-MXene Nanosheets with One-step Potentiometric Detection of Programmed Death-ligand 1

This communication describes a simple sensitive one-step potentiometric aptasensing method for quantitative detection of a referenced therapeutic biomarker (programmed death-ligand 1, PD−L1). The aptasensor is constructed by modifying PD−L1-specific aptamer on Ti₃C₂-MXene nanosheets-functionalized electrode. Introduction of PD−L1 induces the specific reaction between PD−L1 and aptamer, thereby resulting in the change of spatial structures. The surface electric potential of modified electrode is shifted upon addition of PD−L1 proteins before and after the reaction of aptamer with the analyte. Interestingly, potentiometric aptamer with Ti₃C₂-MXene nanosheets can achieve a higher sensitivity and a lower detection limit toward target PD−L1 relative to aptamer-modified electrode. Experimental results indicated that the linear range and detection limit of using Ti₃C₂-MXene nanosheets were 0.01–100 ng mL⁻¹ and 7.8 pg mL⁻¹ PD−L1, respectively. Meanwhile, the specificity, reproducibility, storing stability and accuracy of potentiometric aptasensor are acceptable for the screening of PD−L1 in human serum samples.     

Sensitivity of energy eigenstates to perturbation in quantum integrable and chaotic systems

We study the sensitivity of energy eigenstates to small perturbation in quantum integrable and chaotic systems.It is shown that the distribution of rescaled components of perturbed states in unperturbed basis exhibits qualitative difference in these two types of systems:being close to the Gaussian form in quantum chaotic systems,while,far from the Gaussian form in integrable systems.     

SIMULTANEOUS MEASUREMENTS OF THICKNESS AND TEMPERATURE PROFILE IN A WAVY LIQUID FILM FALLING FREELY ON A HEATING WALL

A technique far measuring the thickness of liquid films was developed and successfully tested. The feasibility of this technique was demonstrated in stagnant liquid films as well as in liquid jets. A procedure for in-situ calibration of the thickness probe was developed, allowing the adaptation of the probe to measurements of wavy liquid films. The thickness probe was constructed from a platinum-rhodium wire that was stretched across the film. A constant DC current was supplied through the probe wire, and film thickness was determined from variations in the probe voltage drop resulting from the large differences in the electrical resistances of the wetted and unwetted segments of the wire. Unlike electrical admittance thickness probes, the new probe did not require dissolving an electrolyte in the liquid, making the new probe well suited to studies involving sensible heating of a film of pure dielectric liquid that is in duvet contact with a current-carrying wall. Also presented is a composite probe that facilitated simultaneous measurements of temperature profile across a wavy liquid film and film thickness. Experimental results demonstrate a strong influence of wariness on liquid temperature in a film of deionized water falling freely on the outside wall of a vertical, electrically heated tube for film Reynolds numbers smaller than 10,000.     

基于传感器控制的多级磁阻式电磁炮制作与研究

针对磁阻式电磁发射器的技术特点,设计了一种基于传感器控制的多级电磁炮射击装置,并成功试制了电磁发射装置样品,通过单级加电压和改变炮弹初始位置的方法对样品进行试射,并在此基础上加装三级加速,从而得出三级电磁炮的发射最优配置,试验证明,在280V电压下,炮弹的出口速度达到27.52m/s.     

Spinor Field at the Phase Transition Point of Reissner-Nordström de Sitter Space

The radial parts of Dirac equation between the outer black hole horizon and the cosmological horizon are solved in Reissner-Nordström de Sitter (RNdS) space when it is at the phase transition point. We use an accurate polynomial approximation to approximate the modified tortoise coordinate \(\hat{r}_{*}\) in order to get the inverse function \(r=r(\hat{r}_{*})\) and the potential \(V(\hat{r}_{*})\). Then we use a quantum mechanical method to solve the wave equation numerically. We consider two cases, one is when the two horizons are lying close to each other, the other is when the two horizons are widely separated.     

Amperometric Tyrosinase Biosensor Based on Carbon Nanotube–Titania–Nafion Composite Film

A highly sensitive and stable amperometric tyrosinase biosensor has been developed based on multiwalled carbon nanotube (MWCNT) dispersed in mesoporous composite films of sol–gel‐derived titania and perfluorosulfonated ionomer (Nafion). Tyrosinase was immobilized within a thin film of MWCNT–titania–Nafion composite film coated on a glassy carbon electrode. Phenolic compounds were determined by the direct reduction of biocatalytically‐liberated quinone species at ?100 mV versus Ag/AgCl (3 M NaCl) without a mediator. The present tyrosinase biosensor showed good analytical performances in terms of response time, sensitivity, and stability compared to those obtained with other biosensors based on different sol–gel matrices. Due to the large pore size of the MWCNT–titania–Nafion composite, the present biosensor showed remarkably fast response time with less than 3 s. The present biosensor responds linearly to phenol from 1.0×10^?7 M to 5.0×10^?5 M with an excellent sensitivity of 417 mA/M and a detection limit of 9.5×10^?8 M (S/N=3). The enzyme electrode retained 89% of its initial activity after 2 weeks of storage in 50 mM phosphate buffer at pH 7.0.     

Some Conditions on Real Hypersurfaces in Quaternionic Projective Spaces in Terms of Lie Derivatives

The purpose of this paper is to give a non-existence property with the Lie derivative of the structure tensors φ _i and some characterizations of real hypersurfaces of type A ₁, A ₂ in a quaternionic projective space QP ^m in terms of the Lie derivatives of the second fundamental tensor A and the induced Riemannian metric g on the distribution D ^⊥ = Span {U ₂, U ₂, U ₃}. This revised version was published online in June 2006 with corrections to the Cover Date.     

Self-limiting growth of ZnO films on (0 0 0 1) sapphire substrates by atomic layer deposition at low temperatures using diethyl-zinc and nitrous oxide

Atomic layer deposition (ALD) of zinc oxide (ZnO) films on (0 0 0 1) sapphire substrates was conducted at low temperatures by using diethyl-zinc (DEZn) and nitrous oxide (N₂O) as precursors. It was found that a monolayer-by-monolayer growth regime occurred at 300 °C in a range of DEZn flow rates from 5.7 to 8.7 μmol/min. Furthermore, the temperature self-limiting process window for the ALD-grown ZnO films was also observed ranging from 290 to 310 °C. A deposition mechanism is proposed to explain how saturated growth of ZnO is achieved by using DEZn and N₂O. Transmission spectroscopic studies of the ZnO films prepared in the self-limiting regime show that the transmittances of ZnO films are as high as 80% in visible and near infrared spectra. Experimental results indicate that ZnO films with high optical quality can be achieved by ALD at low temperatures using DEZn and N₂O precursors.     

Near‐Infrared Afterglow Semiconducting Nano‐Polycomplexes for the Multiplex Differentiation of Cancer Exosomes

The detection of exosomes is promising for the early diagnosis of cancer. However, the development of suitable optical sensors remains challenging. We have developed the first luminescent nanosensor for the multiplex differentiation of cancer exosomes that bypasses real‐time light excitation. The sensor is composed of a near‐infrared semiconducting polyelectrolyte (ASPN) that forms a complex with a quencher‐tagged aptamer. The afterglow signal of the nanocomplex (ASPNC), being initially quenched, is turned on in the presence of aptamer‐targeted exosomes. Because detection of the afterglow takes place after the excitation, background signals are minimized, leading to an improved limit of detection that is nearly two orders of magnitude lower than that of fluorescence detection in cell culture media. Also, ASPNC can be easily tailored to detect different exosomal proteins by changing the aptamer sequence. This enables an orthogonal analysis of multiple exosome samples, potentially permitting an accurate identification of the cellular origin of exosomes for cancer diagnosis.     

Preparation of a polyhedral oligomeric silsesquioxanes hybrid monolith via a single‐step ring‐opening polymerization for pressurized capillary electrochromatography

An organic‐silica hybrid monolith was prepared by a single‐step ring‐opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxane (POSS‐epoxy), polyethylenimine (PEI), and β‐cyclodextrin (β‐CD) in a ternary porogenic solvent consisting of polyethylene glycol, 1,4‐butanediol, and 1‐propanol. The framework of POSS‐PEI hybrid monolith could offer well‐defined 3D skeleton, while β‐CD with the ability of forming a host‐guest inclusion complexes with a variety of compounds could show an ability of specific selection. The obtained hybrid monoliths were successfully applied for separation of phenols, benzoic acids, and nucleobases. Especially due to the introduction of β‐CD, positional isomers including hydroquinone and resorcinol, o‐nitrophenol and p‐nitrophenol, as well as p‐chlorophenol and o‐chlorophenol were baseline separated and the column efficiency reached 82 300 plates/m for hydroquinone.