A deep learning-based approach for fully automated segmentation and quantitative analysis of muscle fibers in pig skeletal muscle.

Muscle fiber properties exert a significant influence on pork quality, with cross-sectional area (CSA) being a crucial parameter closely associated with various meat quality indicators, such as shear force. Effectively identifying and segmenting muscle fibers in a robust manner constitutes a vital initial step in determining CSA. This step is highly intricate and time-consuming, necessitating an accurate and automated analytical approach. One limitation of existing methods is their tendency to perform well on high signal-to-noise ratio images of intact, healthy muscle fibers but their lack of validation on more complex image datasets featuring significant morphological changes, such as the presence of ice crystals. In this study, we undertake the fully automatic segmentation of muscle fiber microscopic images stained with myosin adenosine triphosphate (mATPase) activity using a deep learning architecture known as SOLOv2. Our objective is to efficiently derive accurate measurements of muscle fiber size and distribution. Tests conducted on actual images demonstrate that our method adeptly handles the intricate task of muscle fiber segmentation, yielding quantitative results amenable to statistical analysis and displaying reliability comparable to manual analysis.

Photonic chip-based low-noise microwave oscillator.

Numerous modern technologies are reliant on the low-phase noise and exquisite timing stability of microwave signals. Substantial progress has been made in the field of microwave photonics, whereby low-noise microwave signals are generated by the down-conversion of ultrastable optical references using a frequency comb1-3. Such systems, however, are constructed with bulk or fibre optics and are difficult to further reduce in size and power consumption. In this work we address this challenge by leveraging advances in integrated photonics to demonstrate low-noise microwave generation via two-point optical frequency division4,5. Narrow-linewidth self-injection-locked integrated lasers6,7 are stabilized to a miniature Fabry-Pérot cavity8, and the frequency gap between the lasers is divided with an efficient dark soliton frequency comb9. The stabilized output of the microcomb is photodetected to produce a microwave signal at 20 GHz with phase noise of -96 dBc Hz-1 at 100 Hz offset frequency that decreases to -135 dBc Hz-1 at 10 kHz offset-values that are unprecedented for an integrated photonic system. All photonic components can be heterogeneously integrated on a single chip, providing a significant advance for the application of photonics to high-precision navigation, communication and timing systems.

Automatic Recognition and Quantification Feeding Behaviors of Nursery Pigs Using Improved YOLOV5 and Feeding Functional Area Proposals.

A novel method is proposed based on the improved YOLOV5 and feeding functional area proposals to identify the feeding behaviors of nursery piglets in a complex light and different posture environment. The method consists of three steps: first, the corner coordinates of the feeding functional area were set up by using the shape characteristics of the trough proposals and the ratio of the corner point to the image width and height to separate the irregular feeding area; second, a transformer module model was introduced based on YOLOV5 for highly accurate head detection; and third, the feeding behavior was recognized and counted by calculating the proportion of the head in the located feeding area. The pig head dataset was constructed, including 5040 training sets with 54,670 piglet head boxes, and 1200 test sets, and 25,330 piglet head boxes. The improved model achieves a 5.8% increase in the mAP and a 4.7% increase in the F1 score compared with the YOLOV5s model. The model is also applied to analyze the feeding pattern of group-housed nursery pigs in 24 h continuous monitoring and finds that nursing pigs have different feeding rhythms for the day and night, with peak feeding periods at 7:00-9:00 and 15:00-17:00 and decreased feeding periods at 12:00-14:00 and 0:00-6:00. The model provides a solution for identifying and quantifying pig feeding behaviors and offers a data basis for adjusting the farm feeding scheme.

Posture Detection of Individual Pigs Based on Lightweight Convolution Neural Networks and Efficient Channel-Wise Attention.

In this paper, a lightweight channel-wise attention model is proposed for the real-time detection of five representative pig postures: standing, lying on the belly, lying on the side, sitting, and mounting. An optimized compressed block with symmetrical structure is proposed based on model structure and parameter statistics, and the efficient channel attention modules are considered as a channel-wise mechanism to improve the model architecture.The results show that the algorithm's average precision in detecting standing, lying on the belly, lying on the side, sitting, and mounting is 97.7%, 95.2%, 95.7%, 87.5%, and 84.1%, respectively, and the speed of inference is around 63 ms (CPU = i7, RAM = 8G) per postures image. Compared with state-of-the-art models (ResNet50, Darknet53, CSPDarknet53, MobileNetV3-Large, and MobileNetV3-Small), the proposed model has fewer model parameters and lower computation complexity. The statistical results of the postures (with continuous 24 h monitoring) show that some pigs will eat in the early morning, and the peak of the pig's feeding appears after the input of new feed, which reflects the health of the pig herd for farmers.

High-throughput label-free molecular fingerprinting flow cytometry.

Flow cytometry is an indispensable tool in biology for counting and analyzing single cells in large heterogeneous populations. However, it predominantly relies on fluorescent labeling to differentiate cells and, hence, comes with several fundamental drawbacks. Here, we present a high-throughput Raman flow cytometer on a microfluidic chip that chemically probes single live cells in a label-free manner. It is based on a rapid-scan Fourier-transform coherent anti-Stokes Raman scattering spectrometer as an optical interrogator, enabling us to obtain the broadband molecular vibrational spectrum of every single cell in the fingerprint region (400 to 1600 cm-1) with a record-high throughput of ~2000 events/s. As a practical application of the method not feasible with conventional flow cytometry, we demonstrate high-throughput label-free single-cell analysis of the astaxanthin productivity and photosynthetic dynamics of Haematococcus lacustris.

MG53, A Novel Regulator of KChIP2 and Ito,f, Plays a Critical Role in Electrophysiological Remodeling in Cardiac Hypertrophy.

BACKGROUND: KChIP2 (K+ channel interacting protein) is the auxiliary subunit of the fast transient outward K+ current ( Ito,f) in the heart, and insufficient KChIP2 expression induces Ito,f downregulation and arrhythmogenesis in cardiac hypertrophy. Studies have shown muscle-specific mitsugumin 53 (MG53) has promiscuity of function in the context of normal and diseased heart. This study investigates the possible roles of cardiac MG53 in regulation of KChIP2 expression and Ito,f, and the arrhythmogenic potential in hypertrophy. METHODS: MG53 expression is manipulated by genetic ablation of MG53 in mice and adenoviral overexpression or knockdown of MG53 by RNA interference in cultured neonatal rat ventricular myocytes. Cardiomyocyte hypertrophy is produced by phenylephrine stimulation in neonatal rat ventricular myocytes, and pressure overload-induced mouse cardiac hypertrophy is produced by transverse aortic constriction. RESULTS: KChIP2 expression and Ito,f density are downregulated in hearts from MG53-knockout mice and MG53-knockdown neonatal rat ventricular myocytes, but upregulated in MG53-overexpressing cells. In phenylephrine-induced cardiomyocyte hypertrophy, MG53 expression is reduced with concomitant downregulation of KChIP2 and Ito,f, which can be reversed by MG53 overexpression, but exaggerated by MG53 knockdown. MG53 knockout enhances Ito,f remodeling and action potential duration prolongation and increases susceptibility to ventricular arrhythmia in mouse cardiac hypertrophy. Mechanistically, MG53 regulates NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activity and subsequently controls KChIP2 transcription. Chromatin immunoprecipitation demonstrates NF-κB protein has interaction with KChIP2 gene. MG53 overexpression decreases, whereas MG53 knockdown increases NF-κB enrichment at the 5' regulatory region of KChIP2 gene. Normalizing NF-κB activity reverses the alterations in KChIP2 in MG53-overexpressing or knockdown cells. Coimmunoprecipitation and Western blotting assays demonstrate MG53 has physical interaction with TAK1 (transforming growth factor-b [TGFb]-activated kinase 1) and IκBα (nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha), critical components of the NF-κB pathway. CONCLUSIONS: These findings establish MG53 as a novel regulator of KChIP2 and Ito,f by modulating NF-κB activity and reveal its critical role in electrophysiological remodeling in cardiac hypertrophy.

Rapid-scan Fourier-transform coherent anti-Stokes Raman scattering spectroscopy with heterodyne detection.

High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.

Decreased KCNE2 Expression Participates in the Development of Cardiac Hypertrophy by Regulation of Calcineurin-NFAT (Nuclear Factor of Activated T Cells) and Mitogen-Activated Protein Kinase Pathways.

BACKGROUND: KCNE2 is a promiscuous auxiliary subunit of voltage-gated cation channels. A recent work demonstrated that KCNE2 regulates L-type Ca2+ channels. Given the important roles of altered Ca2+ signaling in structural and functional remodeling in diseased hearts, this study investigated whether KCNE2 participates in the development of pathological hypertrophy. METHODS AND RESULTS: We found that cardiac KCNE2 expression was significantly decreased in phenylephrine-induced cardiomyocyte hypertrophy in neonatal rat ventricular myocytes and in transverse aortic constriction-induced cardiac hypertrophy in mice, as well as in dilated cardiomyopathy in human. Knockdown of KCNE2 in neonatal rat ventricular myocytes reproduced hypertrophy by increasing the expression of ANP (atrial natriuretic peptide) and ß-MHC (ß-myosin heavy chain), and cell surface area, whereas overexpression of KCNE2 attenuated phenylephrine-induced cardiomyocyte hypertrophy. Knockdown of KCNE2 increased intracellular Ca2+ transient, calcineurin activity, and nuclear NFAT (nuclear factor of activated T cells) protein levels, and pretreatment with inhibitor of L-type Ca2+ channel (nifedipine) or calcineurin (FK506) attenuated the activation of calcineurin-NFAT pathway and cardiomyocyte hypertrophy. Meanwhile, the phosphorylation levels of p38, extracellular signal-regulated kinase 1/2, and c-Jun N-terminal kinase were increased, and inhibiting the 3 cascades of mitogen-activated protein kinase reduced cardiomyocyte hypertrophy induced by KCNE2 knockdown. Overexpression of KCNE2 in heart by ultrasound-microbubble-mediated gene transfer suppressed the development of hypertrophy and activation of calcineurin-NFAT and mitogen-activated protein kinase pathways in transverse aortic constriction mice. CONCLUSIONS: This study demonstrates that cardiac KCNE2 expression is decreased and contributes to the development of hypertrophy via activation of calcineurin-NFAT and mitogen-activated protein kinase pathways. Targeting KCNE2 is a potential therapeutic strategy for the treatment of hypertrophy.

C-reactive protein stimulates RAGE expression in human coronary artery endothelial cells in vitro via ROS generation and ERK/NF-κB activation.

AIM: The receptor for advanced glycation end-products (RAGE) plays an important role in development of atherosclerosis, and C-reactive protein (CRP) has been found to stimulate its expression in endothelial cells. In this study we investigated how CRP regulated the expression of RAGE in human coronary artery endothelial cells (HCAECs). METHODS: HCAECs were treated in vitro with CRP (50 µg/mL) in combination with a variety of inhibitors. ROS generation was determined by immunocytochemistry and flow cytometry. The RAGE expression and phosphorylation of relevant signaling proteins were measured using Western blot analyses. RESULTS: CRP stimulated the expression of RAGE in the cells, accompanied by markedly increased ROS generation, phosphorylation of ERK1/2 and NF-κB p65, as well as translocation of NF-κB p65 to the nuclei. CRP also stimulated phosphorylation of JNK and p38 MAPK. Pretreatment of the cells with the ROS scavenger N-acetyl-L-cysteine, ERK inhibitor PD98059 or NF-κB inhibitor PDTC blocked CRP-stimulated RAGE expression, but pretreatment with the NADPH oxidase inhibitor DPI, JNK inhibitor SP600125 or p38 MAPK inhibitor SB203580 did not significantly alter CRP-stimulated RAGE expression. CONCLUSION: CRP stimulates RAGE expression in HCAECs in vitro via ROS generation and activation of the ERK/NF-κB signaling pathway.