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Singlet fission (SF), as an effective way to break through the Shockley–Queisser limit, can dramatically improve energy conversion efficiency in solar cell areas. The formation, separation, and relaxation of triplet-pair excitons directly affect the triplet yield, especially triplet-pair separation; thus, how to enhance the triplet-pair separation rate becomes one of the key points to improve SF efficiency; the decay mechanism where the singlet state is converted into two triplet states is significant for the study of the SF mechanism. Herein, we employ ultrafast transient absorption spectroscopy to study the singlet-fission process of nano-amorphous 6, 13-bis(triisopropylsilylethynyl)-Pentacene (TIPS-pentacene) films in a diamond anvil cell (DAC). A kinetics model related to the structural geometric details, as well as an evaluation of the pressure manipulation impacts, is demonstrated based on the experimental results. The results indicate that pressure manipulation enhanced the triplet-pair separation rates of SF-based materials according to their structural micro-environmental improvement when compressed in DAC, while the triplet-exciton transportation lifetime is prolonged. This work shows that pressure may effectively optimize the structural disorder of SF materials, which were found to improve triplet-pair separation efficiency and potentially offer an effective way to further improve SF efficiency. [ABSTRACT FROM AUTHOR]

Due to their inherent lattice mismatch characteristics, 2D heterostructure interfaces are considered ideal for achieving stable and sustained ultralow friction (superlubricity). Despite extensive research, the current understanding of how interface adhesion affects interlayer friction remains limited. This study focused on graphene/MoS2 and graphene/PdSe2 heterostructure interfaces, where extremely low friction coefficients of ≈10−3 are observed. In contrast, the MoS2/PdSe2 heterostructure interfaces exhibit higher friction coefficients, ≈0.02, primarily due to significant interfacial interactions driven by interlayer charge transfer, which is closely related to the ionic nature of 2D material crystals. These findings indicate that the greater the difference in ionicity between the two 2D materials comprising the sliding interfaces is, the lower the interlayer friction, providing key criteria for designing ultralow friction pairs. Moreover, the experimental results demonstrate that interlayer friction in heterostructure systems is closely associated with the material thickness and interface adhesion strength. These experimental findings are supported by molecular dynamics simulations, further validating the observed friction behavior. By integrating experimental observations with simulation analyses, this study reveals the pivotal role of interface adhesion in regulating interlayer friction and offers new insights into understanding and optimizing the frictional performance of layered solid lubricants. [ABSTRACT FROM AUTHOR]

For input-delayed mechanical system with input amplitude constraints, the consensus control problem of multi-agent system (MAS) based on directed graph topology is studied. For scenarios where only some agents can receive the desired signal, an observer is proposed to enable each agent to observe the desired signal, with exponential convergence of the observation error being proven. In the controller design, the system's input integral in fed back to the controller to eliminate the effects of input delay. By combining the input integral method with the hyperbolic tangent function, the input amplitude in limited while addressing the input delay issue. The FMINCON function in used to optimize the control parameters. Finally, the Lyapunov method in utilized to prove the achievement of control objectives and the asymptotic stability of the closed-loop system. Simulation results demonstrate the effectiveness of the proposed observer and controller n achieving system consensus control. [ABSTRACT FROM AUTHOR]

Background Patients with chronic lymphocytic leukemia (CLL) have reduced seroconversion rates and lower binding antibody (Ab) and neutralizing antibody (NAb) titers than healthy individuals following Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) mRNA vaccination. Here, we dissected vaccine-mediated humoral and cellular responses to understand the mechanisms underlying CLL-induced immune dysfunction. Methods and findings We performed a prospective observational study in SARS-CoV-2 infection-naïve CLL patients (n = 95) and healthy controls (n = 30) who were vaccinated between December 2020 and June 2021. Sixty-one CLL patients and 27 healthy controls received 2 doses of the Pfizer-BioNTech BNT162b2 vaccine, while 34 CLL patients and 3 healthy controls received 2 doses of the Moderna mRNA-1273 vaccine. The median time to analysis was 38 days (IQR, 27 to 83) for CLL patients and 36 days (IQR, 28 to 57) for healthy controls. Testing plasma samples for SARS-CoV-2 anti-spike and receptor-binding domain Abs by enzyme-linked immunosorbent assay (ELISA), we found that all healthy controls seroconverted to both antigens, while CLL patients had lower response rates (68% and 54%) as well as lower median titers (23-fold and 30-fold; both p 23-fold and >17-fold lower median NAb titers (both p 2.4 mg/L), prior therapy, anti-CD20 immunotherapy ( Conclusions CLL pathogenesis is characterized by a progressive loss of adaptive immune functions, including in most treatment-naïve patients, with preexisting memory being preserved longer than the capacity to mount responses to new antigens. In addition, higher NAb titers and response rates identify mRNA-1273 as a superior vaccine for CLL patients., Author(s): Kai Qin 1, Kazuhito Honjo 1, Scott Sherrill-Mix 2, Weimin Liu 2, Regina M. Stoltz 2, Allisa K. Oman 1, Lucinda A. Hall 3, Ran Li 1, Sarah Sterrett [...]

Reliability is one of important index in the analysis and evaluation of mechanical structure. Aiming at the problems of various failure modes and low efficiency of reliability evaluation for complex mechanical structures, the reliability analysis method based on polynomial chaos expansions is applied to the reliability analysis of mechanical structures by combining Monte Carlo random sampling and polynomial chaos expansions. In addition, considering the correlation of parameters and various failure modes in the limit state function, the reliability evaluation method of mechanical structure considering failure correlation is given. Finally, a worm gear two-stage reducer is taken as an example to verify the proposed method according to analyzes the various limit state function of different failure form. The computational results show that the reliability evaluation method based on polynomial chaos expansions is efficient and accurate in mechanical structure reliability analysis. And when failure correlation is considered, it is also simple because of avoiding the complex transformation calculation problem.

Coronavirus disease (COVID-19) is typically diagnosed by reverse transcription PCR (RT-PCR) amplification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA from nasopharyngeal fluids (1). RT-PCR yields cycle threshold ([C.sub.t]) [...]