Functional Ultrasound Imaging of Spinal Cord Hemodynamic Responses to Epidural Electrical Stimulation: A Feasibility Study

This study presents the first implementation of functional ultrasound (fUS) imaging of the spinal cord to monitor local hemodynamic response to epidural electrical spinal cord stimulation (SCS) on two small and large animal models. SCS has been successfully applied to control chronic refractory pain and recently was evolved to alleviate motor impairment in Parkinson's disease and after spinal cord injury. At present, however, the mechanisms underlying SCS remain unclear, and current methods for monitoring SCS are limited in their capacity to provide the required sensitivity and spatiotemporal resolutions to evaluate functional changes in response to SCS. fUS is an emerging technology that has recently shown promising results in monitoring a variety of neural activities associated with the brain. Here we demonstrated the feasibility of performing fUS on two animal models during SCS. We showed in vivo spinal cord hemodynamic responses measured by fUS evoked by different SCS parameters. We also demonstrated that fUS has a higher sensitivity in monitoring spinal cord response than electromyography. The high spatial and temporal resolutions of fUS were demonstrated by localized measurements of hemodynamic responses at different spinal cord segments, and by reliable tracking of spinal cord responses to patterned electrical stimulations, respectively. Finally, we proposed optimized fUS imaging and post-processing methods for spinal cord. These results support feasibility of fUS imaging of the spinal cord and could pave the way for future systematic studies to investigate spinal cord functional organization and the mechanisms of spinal cord neuromodulation in vivo

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Analysis of the Driving Force of Spatial and Temporal Differentiation of Carbon Storage in Taihang Mountains Based on InVEST Model

The Taihang Mountains are an important ecological barrier in China, and their ecosystems have good carbon sink capacity. Studying the spatial-temporal variation characteristics and driving factors of carbon storage in the Taihang Mountains ecosystem provides decision-making for the construction of “dual carbon” projects and the improvement of ecological environment quality in this region. This paper takes the area in the Taihang Mountains as the research area, based on the land use and carbon density data of 2005, 2010, 2015, and 2019 of the Taihang Mountains, calculates the carbon storage in the region with the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model, explores the main factors affecting the spatial differentiation of carbon storage in this region, and analyzes their driving mechanisms by Geodetector. The results show that: (1) From 2005 to 2019, the land use of the Taihang Mountains changed somewhat. The area of forest and construction land increased slightly, while the area of farmland and grassland decreased. (2) The current carbon storage in the Taihang Mountains ranges from 1472.91 × 106 t to 1478.17 × 106 t (t is the abbreviation of ton), and shows a decreasing trend, which is due to the decrease in forest and the increase in construction land. (3) Slope and Normalized Difference Vegetation Index (NDVI) are the main driving factors affecting the spatial variation of carbon storage in the Taihang Mountains ecosystem. Temperature, precipitation, and population density are the secondary factors affecting the spatial variation of carbon storage. (4) The synergy between the driving factors is more potent than the individual factor, which is the most evident between NDVI and slope. This means some areas may have more abundant carbon storage under the combined effect of slope and NDVI

Socioeconomic and Environmental Impacts on Regional Tourism across Chinese Cities: A Spatiotemporal Heterogeneous Perspective

Understanding geospatial impacts of multi-sourced drivers on the tourism industry is of great significance for formulating tourism development policies tailored to regional-specific needs. To date, no research in China has explored the combined impacts of socioeconomic and environmental drivers on city-level tourism from a spatiotemporal heterogeneous perspective. We collected the total tourism revenue indicator and 30 potential influencing factors from 343 cities across China during 2008–2017. Three mainstream regressions and an emerging local spatiotemporal regression named the Bayesian spatiotemporally varying coefficients (Bayesian STVC) model were constructed to investigate the global-scale stationary and local-scale spatiotemporal nonstationary relationships between city-level tourism and various vital drivers. The Bayesian STVC model achieved the best model performance. Globally, eight socioeconomic and environmental factors, average wage (coefficient: 0.47, 95% credible intervals: 0.43–0.51), employed population (−0.14, −0.17–−0.11), GDP per capita (0.47, 0.42–0.52), population density (0.21, 0.16–0.27), night-time light index (−0.01, −0.08–0.05), slope (0.10, 0.06–0.14), vegetation index (0.66, 0.63–0.70), and road network density (0.34, 0.29–0.38), were identified to have nonlinear effects on tourism. Temporally, the main drivers might have gradually changed from the local macro-economic level, population density, and natural environment conditions to the individual economic level over the last decade. Spatially, city-specific dynamic maps of tourism development and geographically clustered influencing maps for eight drivers were produced. In 2017, China formed four significant city-level tourism industry clusters (hot spots, 90% confidence), the locations of which coincide with China’s top four urban agglomerations. Our local spatiotemporal analysis framework for geographical tourism data is expected to provide insights into adjusting regional measures to local conditions and temporal variations in broader social and natural sciences

Effects of temperature, salinity, and irradiance on the growth of harmful algal bloom species Phaeocystis globosa Scherffel (Prymnesiophyceae) isolated from the South China Sea

Blooms of Phaeocystis globosa have been frequently reported in Chinese coastal waters, causing serious damage to marine ecosystems. To better understand the ecological characteristics of P. globosa in Chinese coastal waters that facilitate its rapid expansion, the effects of temperature, salinity and irradiance on the growth of P. globosa from the South China Sea were examined in the laboratory. The saturating irradiance for the growth of P. globosa (I-s) was 60 mu mol/(m(2)center dot s), which was lower than those of other harmful algal species (70-114 mu mol/(m(2)center dot s)). A moderate growth rate of 0.22/d was observed at 2 mu mol/(m(2)center dot s) (the minimum irradiance in the experiment), and photo-inhibition did not occur at 230 mu mol/(m(2)center dot s) (the maximum irradiance in the experiment). Exposed to 42 different combinations of temperatures (10-31 degrees C) and salinities (10-40) under saturating irradiance, P. globosa exhibited its maximum specific growth rate of 0.80/d at the combinations of 24 degrees C and 35, and 27 degrees C and 40. The optimum growth rates (> 0.80/d) were observed at temperatures ranging from 24 to 27 degrees C and salinities from 35 to 40. While P. globosa was able to grow well at temperatures from 20 degrees C to 31 degrees C and salinities from 20 to 40, it could not grow at temperatures lower than 15 degrees C or salinities lower than 15. Factorial analysis revealed that temperature and salinity has similar influences on the growth of this species. This strain of P. globosa not only prefers higher temperatures and higher salinity, but also possesses a flexible nutrient competing strategy, adapted to lower irradiance. Therefore, the P. globosa population from South China Sea should belong to a new ecotype. There is also a potentially high risk of blooms developing in this area throughout the year

OmniSR-M: A Rock Sheet with a Multi-Branch Structure Image Super-Resolution Lightweight Method

With the rapid development of digital core technology, the acquisition of high-resolution rock thin section images has become crucial. Due to the limitation of optical principles, thin section imaging involves a contradiction between resolution and field of view. In order to solve this problem, this paper proposes a lightweight, fully aggregated network with multi-branch structure for super resolution of rock thin section images. The experimental results on the rock thin section dataset demonstrate that the improved method, called OmniSR-M, achieves significant enhancement compared to the original OmniSR method and also surpasses other state-of-the-art methods. OmniSR-M effectively recovers image details while maintaining its lightweight nature. Specifically, OmniSR-M reduces the number of parameters by 26.56% and the computation by 27.66% compared to OmniSR. Moreover, this paper quantitatively analyzes both the facies porosity rate and grain size features in the application scenario. The results show that the images generated by OmniSR-M successfully recover key information about the rock thin section

Hypoxia promotes the migration and invasion of human hepatocarcinoma cells through the HIF-1α–IL-8–Akt axis

Abstract Background Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. The 5-year survival rate remains low despite considerable research into treatments of HCC, including surgery, radiotherapy and chemotherapy. Many mechanisms within HCC still require investigation, including the influence of hypoxia, which has a crucial role in many cancers and is associated with metastasis. Hypoxia inducible factor-1α (HIF-1α) is known to regulate the expression of many chemokines, including interleukin-8 (IL-8), which is associated with tumor metastasis. Although many studies have reported that HIF-1α is associated with HCC migration and invasion, the underlying mechanisms remain unknown. Methods The expression level of HIF-1α was determined in HCC cells. The correlation of IL-8 and HIF-1α expressions was assessed via knockdown of HIF-1α. HCC cells were also used to assess the influence of HIF-1α on HCC cell migration and invasion. LY294002, an inhibitor of the Akt pathway, was used to confirm the associated signaling pathways. Results We observed a significant attenuation of cell migration and invasion after silencing of HIF-1α. Exogenously expressing IL-8 restored migration and invasion. Akt was found to be involved in this process. Conclusion Hypoxia promotes HCC cell migration and invasion through the HIF-1α–IL-8–Akt axis