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Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a pivotal immune checkpoint receptor, playing a crucial role in modulating T-cell activation. In this study, we delved into the underlying mechanism by which a common mutation, G199R, in the cytoplasmic domain of CTLA-4 impacts its inhibitory function. Utilizing nuclear magnetic resonance (NMR) spectroscopy and biochemical techniques, we mapped the conformational changes induced by this mutation and investigated its role in CTLA-4 activity. Our findings reveal that this mutation leads to a distinct conformational alteration, enhancing protein–membrane interactions. Moreover, functional assays demonstrated an improved capacity of the G199R mutant to downregulate T-cell activation, underscoring its potential role in immune-related disorders. These results not only enhance our understanding of CTLA-4 regulatory mechanisms but also provide insights for targeted therapeutic strategies addressing immune dysregulation linked to CTLA-4 mutations. [ABSTRACT FROM AUTHOR]

Engineering light-controlled K+ pumps from Na+-pumping rhodopsins (NaR) greatly expands the scope of optogenetic applications. However, the limited knowledge regarding the kinetic and selective mechanism of K+ uptake has significantly impeded the modification and design of light-controlled K+ pumps, as well as their practical applications in various fields, including neuroscience. In this study, we presented K+-dependent photocycle kinetics and photocurrent of a light-driven Na+ pump called Nonlabens dokdonensis rhodopsin 2 (NdR2). As the concentration of K+ increased, we observed the accelerated decay of M intermediate in the wild type (WT) through flash photolysis. In 100 mM KCl, the lifetime of the M decay was approximately 1.0 s, which shortened to around 0.6 s in 1 M KCl. Additionally, the K+-dependent M decay kinetics were also observed in the G263W/N61P mutant, which transports K+. In 100 mM KCl, the lifetime of the M decay was approximately 2.5 s, which shortened to around 0.2 s in 1 M KCl. According to the competitive model, in high KCl, K+ may be taken up from the cytoplasmic surface, competing with Na+ or H+ during M decay. This was further confirmed by the K+-dependent photocurrent of WT liposome. As the concentration of K+ increased to 500 mM, the amplitude of peak current significantly dropped to approximately ~60%. Titration experiments revealed that the ratio of the rate constant of H+ uptake (kH) to that of K+ uptake (kK) is >108. Compared to the WT, the G263W/N61P mutant exhibited a decrease of approximately 40-fold in kH/kK. Previous studies focused on transforming NaR into K+ pumps have primarily targeted the intracellular ion uptake region of Krokinobacter eikastus rhodopsin 2 (KR2) to enhance K+ uptake. However, our results demonstrate that the naturally occurring WT NdR2 is capable of intracellular K+ uptake without requiring structural modifications on the intracellular region. This discovery provides diverse options for future K+ pump designs. Furthermore, we propose a novel photocurrent-based approach to evaluate K+ uptake, which can serve as a reference for similar studies on other ion pumps. In conclusion, our research not only provides new insights into the mechanism of K+ uptake but also offers a valuable point of reference for the development of optogenetic tools and other applications in this field. [ABSTRACT FROM AUTHOR]

A dual-coil inductive displacement transducer is a non-contact type measuring element for measuring displacement and is widely used in large power equipment systems such as construction machinery and agricultural equipment. However, the effect of the coil excitation method on the performance of dual-coil inductive displacement sensors has not been studied. This paper investigates the impact of different coil excitation methods on the operating performance of displacement transducers. The working principle, electromagnetic characteristics, and electrical characteristics were analyzed by building a mathematical model. A transducer measurement device was used to determine the relationship between core displacement and coil inductance. Three coil excitation methods were proposed, and the effects of the three coil excitation methods on the amplitude variation, phase shift, linearity, and sensitivity of the output signal were studied by simulation based on the AD630 chip as the core of the conditioning circuit. Finally, the study's feasibility was demonstrated by comparing the experiment to the simulation. The results show that, under the uniform magnetic field strength distribution in the coil, the coil voltage variation is proportional to the inductive core displacement. The amplitude variation is the largest for the dual-coil series three-wire (DCSTW) and is the same for the dual-coil series four-wire (DCSFW) and dual-coil parallel differential (DCPD). DCSFW has an enormous phase shift. DCSTW has the best linearity. The research in this paper provides a theoretical basis for selecting a suitable coil excitation, which is conducive to further improving the operating performance of dual-coil inductive displacement transducers. [ABSTRACT FROM AUTHOR]

Ferroelectric photoelectric devices show promising applications in artificial vision systems. However, this type of devices used in artificial vision systems exhibits low photoresponsivity and this limited cyclability of photocurrents, which hinders the progress of artificial vision systems. In this study, an artificial vision system is constructed with high photoresponsivity, fast photoresponse speed, and high read/write speed based on the Pd/PbZr0.4Ti0.6O3/La0.3Sr0.7MnO3/LaAlO3 ferroelectric photomemristor. The high optical response (18.86 nanoamperes) and read/write speeds (50 nanoseconds) of the device significantly improve the robustness and speed of the neuromorphic visual system while reducing power consumption for recognition. The artificial vision system developed in this study provides excellent real‐time image processing capabilities, including edge detection and classification with 100% accuracy for musical key patterns, and it is expected to offer great potential for the development of high‐performance self‐powered artificial vision systems. [ABSTRACT FROM AUTHOR]

In this paper, the finite thrust nonplanar transfer and cooperative rendezvous are investigated. The indirect method is adopted in the optimization process. The energy-optimal to fuel-optimal continuation is performed by using the homotopy method. An initial guess generator (IGG) is designed based on a simplified dynamical model to overcome the difficulty in providing the initial guess. Some reasonable simplifications on the dynamical model are applied based on the near-circular near-coplanar transfer. The initial guess can be obtained by analytically solving a system of linear equations. Therefore, the IGG has high computational efficiency. Moreover, the terminal time and state are estimated by IGG to deal with the cooperative rendezvous problem. Numerical examples are presented and the validity of the "IGG-Homotopy" combined algorithm is verified. [ABSTRACT FROM AUTHOR]

This article studies the structure of hydraulic spool valve and the influence of different pressure differences on steady-state flow force. An improved scheme of designing a jet guide groove on the valve core is proposed to compensate for steady-state flow force. This article uses the CFD method to study the influence of spool valve structural parameters on steady-state flow force. The response surface method is used to establish the Polynomial regression model of the steady-state flow force, and the optimal structure size of the jet guide slot is obtained. The results indicate that the flow force increases with the increase of pressure difference. Moreover, under the same operating conditions, the absolute flow force of the spool valve with jet guide groove is smaller than that of the spool valve without jet guide groove. Therefore, the jet guide groove can effectively compensate for steady-state flow force, improve the control accuracy of the valve, and improve the stability of the spool valve. • This paper describes the principle of hydrodynamic force generation and the effect of spool structure on hydrodynamic force. • A new deflector structure consisting of a combination of triangles and circular arcs is proposed. • This structure reduces the impact of the fluid on the spool and reduces the loss of the spool. • Velocity and pressure clouds for different structures are derived and optimal structural parameters are derived. [ABSTRACT FROM AUTHOR]

A double-coil inductive displacement transducer is a non-contact element for measuring displacement and is widely used in large power equipment systems such as construction machinery and agricultural machinery equipment. The type of coil excitation signal has an impact on the performance of the transducer, but there is little research on this. Therefore, the influence of the coil excitation signal on transducer performance is investigated. The working principle and characteristics of the double-coil inductive displacement transducer are analyzed, and the circuit simulation model of the transducer is established. From the aspects of phase shift, linearity, and sensitivity, the effects of a sine signal, a triangle signal, and a pulse signal on the transducer are compared and analyzed. The results show that the average phase shift, linearity, and sensitivity of the sine signal were 11.53°, 1.61%, and 0.372 V/mm, respectively; the average phase shift, linearity and sensitivity of the triangular signal were 1.38°, 1.56%, and 0.300 V/mm, respectively; and the average phase shift, linearity, and sensitivity of the pulse signal were 0.73°, 1.95%, and 0.621 V/mm, respectively. It can be seen that the phase shift of a triangle signal and a pulse signal is smaller than that of a sine signal, which can result in better signal phase-locked processing. The linearity of the triangle signal is better than the sine signal, and the sensitivity of the pulse signal is better than that of the sine signal. [ABSTRACT FROM AUTHOR]

The distributed transmit beamforming has recently been discussed as an energy-effective technique in wireless communication systems. A common ground of various techniques is that the destination node transmits a beacon signal or feedback to assist source nodes to synchronize signals. However, this approach is not appropriate for a radar system since the destination is a non-cooperative target of an unknown location. In our paper, we propose a novel synchronization strategy for a distributed multiple-element beamfoming radar system. Source nodes estimate parameters of beacon signals transmitted from others to get their local synchronization information. The channel information of the phase propagation delay is transmitted to nodes via the reflected beacon signals as well. Next, each node generates appropriate parameters to form a beamforming signal at the target. Transmit beamforming signals of all nodes will combine coherently at the target compensating for different propagation delay. We analyse the influence of the local oscillation accuracy and the parameter estimation errors on the performance of the proposed synchronization scheme. The results of numerical simulations illustrate that this synchronization scheme is effective to enable the transmit beamforming in a distributed multi-element radar system. [ABSTRACT FROM AUTHOR]

A jet guiding groove is designed on the spool to compensate the steady-state flow force. The steady-state flow force model is analyzed and derived. The influence of structural parameters on steady-state flow force is studied by CFD simulation. The response surface method is used to construct the steady-state flow force polynomial regression model. The optimal structure size of the jet guiding groove is obtained. The steady-state flow force compensation coefficient is defined and calculated. Results show that the compensation effect decreases with the increase of pressure difference. However, at the same pressure difference, the absolute value of the compensation coefficient of the spool with jet guiding groove is less than that of the spool without jet guiding groove. The results show that the jet guiding groove can effectively compensate the steady-state flow force and improve the control accuracy of the valve. • Jet guiding groove can effectively compensate the flow force. • The influence of structural parameters on steady-state flow force is studied by CFD simulation. • The flow force model is established by response surface and the optimal parameters are calculated. • The flow force compensation coefficient can be used to analyze the compensation characteristics. [ABSTRACT FROM AUTHOR]

• The reaction images for different equivalence ratio were shown. • The OH* imges and NO x production in the MILD combustion zone were analyzed. • The NO x reduction mechanism prevails over the NO x formation mechanism under MILD mode. The effect of equivalence ratio and staging ratio on the CH 4 MILD (Moderate or Intense Low-oxygen Dilution) combustion was examined in an axially staged MILD combustor. The results were presented on reactant temperature and dilution as well as the ignition delay time through CRN (chemical reaction network) calculation. Also, the data on the OH* radicals distribution and exhaust emissions were obtained using experiments. Higher staging ratio induces the high temperature low oxygen thermodynamic condition required for MILD scheme, yet reduces the ignition delay time. An expanded and downstream moved reaction region was observed at higher equivalence ratio. Reduced and even negative NO x emissions from the MILD combustion zone are acquired at high staging ratio, implying that the NO x reduction mechanism is superior to the NO x formation mechanism in the MILD combustion zone. The opposite effect of staging ratio on the CO emission for low equivalence ratio and high equivalence ratio is also observed. With primary air swirled in the primary combustion zone, the staged combustor exhibits an excellence performance with distributed reaction region and ultra-low NO x and CO emissions under gas turbine relevant lean operating condition. [ABSTRACT FROM AUTHOR]

• The flow , flame and emission are presented under furnace operation condition. • Smooth thermal field and reduced emissions were observed for MILD mode. • Higer thermal input and excess air ratio anticipate the realization of MILD mode. • From nonpremixed to premixed MILD mode, the NO x formation is suppressed. • Heat balance under premixed MILD combustion was presented in the present work. To promote the application of MILD scheme in furnace, the present work was performed to evaluate the effect of thermal input, excess air coefficient and combustion mode on the MILD combustion at high thermal level (thermal input varies from 600 to 786 kW); meanwhile, the heat from the utilized furnace was extracted by an annular water jacket and a corundum tube was installed in the furnace tube to create the high temperature atmosphere. The results were presented on flow field using numerical simulations and on global flame signatures, temperature/species distribution and exhaust emissions using experiments. Better combustion performance of MILD mode than conventional swirling diffusion combustion mode was verified in the present work. The positive effect of increased thermal input and excess air coefficient on gas recirculation, thermal uniformity and exhaust emissions reduction was observed. In the MILD combustion regime, the switching from nonpremixed to premixed combustion resulted in lower oxygen level and reduced reaction temperature in the combustion region, also much lower NO x emissions and slightly higher CO emission were observed. At 786 kW thermal input, the reaction zone covers the entire combustion chamber; meanwhile, low NO x emission level of 32 ppm@3%O 2 are achieved for premixed MILD combustion mode. The MILD regime was established for natural gas fueled furnace with colorless distributed combustion and suppressed NO x and CO emissions. [ABSTRACT FROM AUTHOR]