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Calcium imaging with protein-based indicators1,2 is widely used to follow neural activity in intact nervous systems, but current protein sensors report neural activity at timescales much slower than electrical signalling and are limited by trade-offs between sensitivity and kinetics. Here we used large-scale screening and structure-guided mutagenesis to develop and optimize several fast and sensitive GCaMP-type indicators3-8. The resulting 'jGCaMP8' sensors, based on the calcium-binding protein calmodulin and a fragment of endothelial nitric oxide synthase, have ultra-fast kinetics (half-rise times of 2 ms) and the highest sensitivity for neural activity reported for a protein-based calcium sensor. jGCaMP8 sensors will allow tracking of large populations of neurons on timescales relevant to neural computation.

In the past, comprehensive information was imperative for image processing, prompting a preference for high-depth cameras. However, in our research, we discovered that the abundance of image details may impede phase retrieval. Consequently, this paper presents an iterative phase retrieval method based on a low bit depth. Through simulations and experiments, this approach has proven effective in evidently enhancing phase retrieval outcomes. Furthermore, the concept of low bit depth holds promise for broader application across diverse domains within the field of image retrieval. [ABSTRACT FROM AUTHOR]

The pineal gland has evolved from a photoreceptive organ in fish to a neuroendocrine organ in mammals. This study integrated multiple daytime single‐cell RNA‐seq datasets from the pineal glands of zebrafish, rats, and monkeys, providing a detailed examination of the evolutionary transition at single‐cell resolution. We identified key factors responsible for the anatomical and functional transformation of the pineal gland. We retrieved and integrated daytime single‐cell transcriptomic datasets from the pineal glands of zebrafish, rats, and monkeys, resulting in a total of 22 431 cells after rigorous quality filtering. Comparative analysis was then conducted to elucidate the evolution of pineal cells, their photosensitivity, their role in melatonin production, and the signaling processes within the glands of these species. Our analysis identified distinct cellular compositions of the pineal gland in zebrafish, rats, and monkeys. Zebrafish photoreceptors exhibited comprehensive phototransduction gene expression, while specific genes, including transducin (Gngt1, Gnb3, and Gngt2) and phosducin (Pdc), were consistently present in mammalian pinealocytes. We found transcriptional similarities between the pineal gland and retina, underscoring shared evolutionary and functional pathways. Zebrafish displayed unique light‐responsive circadian gene activity compared to rats and monkeys. Key ligand‐receptor interactions were identified, especially involving MDK and PTN, influencing melatonin synthesis across species. Furthermore, we observed species‐specific GPCR (G protein‐coupled receptors) expressions related to melatonin synthesis and their alignment with retinal expressions. Our findings also highlighted specific transcription factors (TFs) and regulatory networks associated with pineal gland evolution and function. Our study provides a detailed analysis of the pineal gland's evolution from fish to mammals. We identified key transcriptional changes and controls that highlight the gland's functional diversity. Notably, we found significant ligand‐receptor interactions influencing melatonin synthesis and demonstrated parallels between pineal and retinal expressions. These insights enhance our understanding of the pineal gland's role in phototransduction, melatonin production, and circadian rhythms in vertebrates. [ABSTRACT FROM AUTHOR]

An excellent organolead halide perovskite film is important for the good performance of perovskite solar cells (PSCs). However, defects in perovskite crystals can affect the photovoltaic properties and stability of solar cells. To solve this problem, this study incorporated a complex of CdS and Cd(SCN2H4)2Cl2 into the CH3NH3PbI3 active layer. The effects of different doping concentrations of CdS and Cd(SCN2H4)2Cl2 on the performance and stability of PSCs were analyzed. Results showed that doping appropriate incorporation concentrations of CdS and Cd(SCN2H4)2Cl2 in CH3NH3PbI3 can improve the performance of the prepared solar cells. In specific, CdS and Cd(SCN2H4)2Cl2 can effectively passivate the defects in perovskite crystals, thereby suppressing the charge recombination in PSCs and promoting the charge extraction at the TiO2/perovskite interface. Due to the reduction of perovskite crystal defects and the enhancement of compactness of the CdS:Cd(SCN2H4)2Cl2:CH3NH3PbI3 composite film, the stability of PSCs is significantly improved. [ABSTRACT FROM AUTHOR]

The development of a hole transport layer (HTL) with persistent high conductivity, good moisture/oxygen barrier ability, and suitable passivation ability of perovskite defects is very important for achieving high power conversion efficiency (PCE) and long‐term stability of perovskite solar cells (PSCs). However, the state‐of‐the art HTL, lithium bis(trifluoromethanesulfonyl)‐imide (Li‐TFSI)‐doped 2,2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD), does not have these abilities. Herein, the incorporation of antimony sulfide (Sb2S3) nanoparticles as a multifunctional additive into spiro‐OMeTAD is demonstrated. The Sb2S3 effectively improve the compactness of composite spiro‐OMeTAD:Sb2S3 HTL by inhibiting the Li‐TFSI aggregation and effectively prevent the infiltration of moisture and oxygen into the perovskite layer, resulting in its high chemical stability. More importantly, Sb2S3 not only improves the conductivity and hole mobility of the spiro‐OMeTAD:Sb2S3 through the oxidation of spiro‐OMeTAD by Sb2S3, but also makes the high conductivity more durable and stable in the atmospheric environment. In addition, Sb2S3 also effectively passivates the perovskite defects and accelerates the charge transfer from perovskite layer to HTL. As a consequence, the optimized PSCs based on spiro‐OMeTAD:Sb2S3 HTL exhibit a much higher PCE (22.13%) than that (19.29%) of the PSCs without Sb2S3 and show a greatly improved stability. [ABSTRACT FROM AUTHOR]

Droplet digital polymerase chain reaction (ddPCR) is an effective technique, with unparalleled sensitivity, for the absolute quantification of target nucleic acids. However, current commercial ddPCR devices for detecting the gene chip are time consuming due to complex image stitching. To address this issue, we propose a universal concentration determination system and realize one-time gene chip imaging with high resolution. All the functional units are controlled by self-developed software using the PyQt5 module in Python. Without stitching technology, images of the ddPCR chip (28 mm × 18 mm) containing 20 000 independent 0.81 nL micro chambers can be obtained in less than 15 seconds, which saves about 165 seconds. A white laser light source (2 mW cm−2) was employed as a substitute for the mercury lamp. Its wavelength matches well with typical fluorescent dyes (e.g., HEX, ROX and Cy5), and thus it can strengthen the fluorescence intensity for weak signals. The results also demonstrated that the correlation coefficient for the measured concentration and theoretical value was above 99%, by testing the ddPCR products with COVID-19 virus. Such a system can greatly reduce the time required for image acquisition and DNA concentration determination, and thus is able to speed up the lab-to-application process for ddPCR technology. [ABSTRACT FROM AUTHOR]