Protein crystallization in vivo

Protein crystallization in vivo provides some fascinating examples of biological self-assembly. Here, we provide a selective survey to show the diversity of functions for which protein crystals are used, and the physical properties of the crystals thatare exploited. Where known, we emphasize how the nature of the protein-protein interactions leads to control of the crystallization behaviour.Comment: 17 pages, 1 figur

Active coupled-resonator optical waveguides. I. Gain enhancement and noise

We use a tight-binding formalism in the time domain to analyze the effect of resonant gain enhancement and spontaneous emission noise in amplifying coupled-resonator optical waveguides (CROWs). We find the net amplification of a wave propagating in a CROW does not always vary with the group velocity, and depends strongly on the termination and excitation of these structures. The signal-to-noise ratio and noise figure of CROW amplifiers are derived in the tight-binding formalism as well. The physical interpretations and practical consequences of the theoretical results are discussed

Optical bright and dark states in side-coupled resonator structures

We analyze side-coupled standing-wave cavity structures consisting of Fabry-Perot and photonic crystal resonators coupled to two waveguides. We show that optical bright and dark states, analogous to those observed in coherent light-matter interactions, can exist in these systems. These structures may be useful for variable, switchable delay lines

Microring coupled-resonator optical waveguides

We use transfer matrices to obtain the dispersion relations of microring coupled-resonator optical waveguides (CROWs). We also analyze pulse propagation through finite and semi-infinite microring CROWs. The results agree well with FDTD simulations

Least-Squares Approximation by Elements from Matrix Orbits Achieved by Gradient Flows on Compact Lie Groups

Let $S(A)$ denote the orbit of a complex or real matrix $A$ under a certain equivalence relation such as unitary similarity, unitary equivalence, unitary congruences etc. Efficient gradient-flow algorithms are constructed to determine the best approximation of a given matrix $A_0$ by the sum of matrices in $S(A_1), ..., S(A_N)$ in the sense of finding the Euclidean least-squares distance $$\min \{\|X_1+ ... + X_N - A_0\|: X_j \in S(A_j), j = 1, >..., N\}.$$ Connections of the results to different pure and applied areas are discussed

Effects of Aerobic Exercise and High-Intensity Interval Training on the Mental Health of Adolescents Living in Poverty: Protocol for a Randomized Controlled Trial

Background: The increasing rate of mental health issues among adolescents has recently been a considerable concern in Hong Kong. In particular, adolescents with low socioeconomic status (SES) are likely to experience poor mental health, including low self-esteem and high levels of anxiety, anger, and depression. Previous research has found that physical activities have a positive impact on improving mental health outcomes among adolescents. However, approximately 96% of adolescents in Hong Kong do not engage in regular exercise, which potentially increases the risk of poor mental health. Objective: In this study, we aim to examine whether changes in the 3 indicators (reduced ill-being, enhanced well-being, and cognitive functions) of mental health among adolescents with low SES are evident before and after exercise. In addition, this study compares the effectiveness of aerobic exercise and high-intensity interval training on these indicators among adolescents with low SES. Methods: A total of 78 participants from low-income families aged between 12 and 15 years from 3 to 4 secondary schools will be recruited for this study. They will be randomly assigned to either an aerobic exercise group (26/78, 33%), a high-intensity interval training group (26/78, 33%), or a control group (26/78, 33%). Participants in the first 2 groups will take part in a 10-week training program period. Participants in the control group will participate in other physical activities during the same intervention period. The training sessions will be conducted 3 times per week on nonconsecutive days. A range of neuropsychological tests and psychometric scales will be used to measure the executive functions and indicators of psychological well-being and ill-being, including enjoyment, self-efficacy, mood, depression, anxiety, and stress at pretest, posttest, and follow-up assessments. Results: The project was funded in 2021 by the Research Matching Grant Scheme, through the University Grants Committee of the Hong Kong Special Administrative Region Government. Ethical approval has been obtained from the author’s institution. Participant recruitment will begin in January 2022 and continue through to April 2022. Data collection and follow-up are expected to be completed by the end of 2022. The results are expected to be submitted for publication in 2023. Conclusions: The findings will help inform policy makers and practitioners in promoting the importance of physical exercise to enhance mental health