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Abstract Cryo-electron microscopy (cryo-EM) has been widely used to reveal the structures of proteins at atomic resolution. One key challenge is that almost all proteins are predominantly adsorbed to the air-water interface during standard cryo-EM specimen preparation. The interaction of proteins with air-water interface will significantly impede the success of reconstruction and achievable resolution. Here, we highlight the critical role of impenetrable surfactant monolayers in passivating the air-water interface problems, and develop a robust effective method for high-resolution cryo-EM analysis, by using the superstructure GSAMs which comprises surfactant self-assembled monolayers (SAMs) and graphene membrane. The GSAMs works well in enriching the orientations and improving particle utilization ratio of multiple proteins, facilitating the 3.3-Å resolution reconstruction of a 100-kDa protein complex (ACE2-RBD), which shows strong preferential orientation using traditional specimen preparation protocol. Additionally, we demonstrate that GSAMs enables the successful determinations of small proteins (

Abstract Studies investigating the relationship between dietary vitamin B1 intake and risk of Hyperuricemia (HU) are scarce, the present study aimed to examine the association of dietary vitamin B1 intake and HU among adults. This cross-sectional study included 5750 adults whose data derived from National Health and Nutrition Examination Survey (NHANES) from March 2017 to March 2020. The dietary intake of vitamin B1 was assessed using 24-h dietary recall interviews. The characteristics of study participants were grouped into five levels according to the levels of vitamin B1 quintile. Multivariate logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence interval (CI) of HU, according to the vitamin B1 intake quintile for male and female separately. The dose–response relationship was determined by the restricted cubic spline (RCS). Smoothed curve fitting was used to assess serum uric acid concentration versus dietary vitamin B1 intake in the study population. The prevalence of hyperuricemia was 18.90% (20.15% and 17.79% for males and females, respectively) in the United States from March 2017 to March 2020. Multiple logistic regression analyses showed that in the male population, the HU ratio (OR) of vitamin B1 intake in Q2 to Q5 compared with the lowest quintile (Q1) was 0.75 (95% CI 0.52, 1.09), 0.70 (95% CI 0.48, 1.02), 0.66 (95% CI 0.44, 0.99) and 0.55 (95% CI 0.34, 0.90). The P for trend was 0.028. In women, the ORs for vitamin B1 intake Q2 to Q5 were 0.87 (95% CI 0.64, 1.19), 0.97 (0.68–1.38), 1.05 (0.69–1.60) and 0.75 (0.42–1.34), respectively. The P for trend was 0.876. The RCS curve revealed a linear relationship between vitamin B1 intake and the risk of hyperuricemia in men (P nonlinear = 0.401). Smoothed curve fitting demonstrated a negative association between vitamin B1 intake and serum uric acid concentration in men, whereas there was no significant association between dietary vitamin B1 intake and the risk of hyperuricemia in women. In the US adult population, dietary vitamin B1 intake was negatively associated with hyperuricemia in males.

Analyzing how rail transit stations affect the land use changes around them in space and time is important for forecasting the future interaction between new stations and land use and for adjusting and optimizing planning schemes. Based on the design concept of station-city integration, this paper uses Zhongshanba Station of Guangzhou Metro as a case study. It examines the land use evolution around the station and predicts the future land use changes around the double-track transfer station of Line 5 and Line 11, using the POI kernel density and the passenger flow heat map of the existing station in the old city. The results show that the POI and passenger flow heat map are innovative driving variables that can increase the simulation accuracy of the CA-Markov model to 91.86%. The prediction results also show that public management-service land and residential land will increase while industrial land will decrease. Although garden land will expand, the surrounding ecological area is still inadequate. Finally, this paper provides some strategies for optimizing subway stations and planning urban land use.

Organophosphorus poisoning is a critical condition that can cause central nervous system depression, respiratory failure, and death early on. As its clinical manifestations closely resemble those of carbamate pesticide poisoning, the aim of this case study is to present a case of misdiagnosis, initially identifying carbofuran poisoning as organophosphate in a patient suspect of a heatstroke. We also present a case of intentional self-poisoning with organophosphate dichlorvos to underline the likelihood of pesticide poisoning in patients exhibiting acute cholinergic symptoms when the ingested substance is not known. In such cases, empirical treatment with atropine and oxime can be started pending timely differential diagnosis to adjust treatment as necessary.

The imbalance of natural, social, and economic systems has engendered a multitude of environmental challenges, resulting in the increasingly vulnerable ecological environments. To mitigate the adverse effects of external disturbances on ecosystems, ecological vulnerability assessment (EVA) has emerged as a pivotal research domain in environmental science. Therefore, EVA of the Loess Plateau from 2000 to 2020 was conducted, utilizing a sensitivity-resilience-pressure (SRP) model based on ecological zoning, and identifying its driving factors. The findings revealed an overall ecological vulnerability index (EVI) of 0.53, signifying indicating a moderate vulnerability, and it exhibited a decreasing trend, with EVI of 0.58, 0.53, and 0.49, respectively. The EVI in the five ecological zones was: S5 (sandy desert region, 0.80) > S3 (agricultural irrigation regions, 0.66) > S1 (loess hilly and gully region, 0.52) > S4 (river valley plain region, 0.43) > S2 (Earth-rocky mountainous region, 0.38). Notably, a declining pattern in EVI was observed in S5, S1, and S3, while S2 and S4 experienced an increase. Moreover, the grade of EV reduced from the northwest to the southeast during all three periods, with a distinct positive spatial correlation and the presence of hot spots, sub-hot spots, sub-cold spots, and cold spots. Vegetation cover, humidity, and dryness were the main driving factors of EV, displaying significant interrelationships among all indicators. Finally, targeted protective strategies were proposed to enhance EV in different ecological zones of the Loess Plateau. Overall, EV in five ecological zones exhibited distinct spatiotemporal variation. This study offered a valuable framework of EVA applicable to arid areas, thereby promoting the ecological management and healthy development in vulnerable regions.

ObjectiveThe occurrence of ischemic stroke (IS) is closely related to the characteristics of carotid plaque (CP). Due to the effect of stroke risk stratification based on B-mode ultrasound (US) and contrast-enhanced ultrasound (CEUS) that has not been studied in patients with low and intermediate carotid stenosis, we construct and validate a CP score and ischemic stroke risk stratification (ISRS) using a combination of B-mode and CEUS, in order to provide new convenient strategies to stratify these patients to prevent stroke.Materials and methodsThis retrospective study evaluated 705 patients with low and intermediate carotid stenosis who underwent B-mode and CEUS from November 2021 to April 2023. Qualitative B-mode and CEUS features of carotid plaques were analyzed using a univariable and multivariable logistic regression to construct the CP score. Then, we combined the CP score with Essen stroke risk score (ESRS) to develop ISRS.ResultsThis study included a total of 705 patients with low and intermediate carotid stenosis, of which 394 were symptomatic patients (with a mean age of 71.03 ± 10.48 years) and 311 were asymptomatic patients (with a mean age of 65.13 ± 10.31 years). Plaque echogenicity, plaque morphology, carotid intima-media thickness in B-mode US and intraplaque neovascularization grading and perfusion pattern in CEUS were significantly associated with IS. The ISRS incorporating these five predictors and ESRS showed good discrimination and calibration in both primary cohort [area under the curve (AUC), 0.91; Hosmer–Lemeshow test, p = 0.903] and validation cohort (AUC, 0.84; Hosmer–Lemeshow test, p = 0.886).ConclusionWe developed an effective and practical tool to identify and stratify patients with low and intermediate carotid stenosis, based on the CP score and ISRS estimation. Our study may provide new insights into managing patients with no indication of surgery.

As a typical ecologically fragile area, the ecological security of the Loess Plateau has been seriously threatened. Ecological security patterns (ESP) have gradually become an effective method for protecting ecological security and supporting the management and sustainable development of ecosystems. Therefore, this study constructed a novel ESP based on ecological “function–structure”, utilizing minimum cumulative resistance (MCR) to identify ecological source areas and corridors. Additionally, time scales were introduced into the ESP, allowing for a comprehensive analysis of the spatiotemporal heterogeneity of ecological security in the Loess Plateau. The study revealed that the number of ecological sources decreased from southeast to northwest, with 27, 41, and 77 sources covering total areas of 4263.810 km2, 18,566.034 km2, and 113,209.595 km2 from 2000 to 2020, respectively. Similarly, the number and complexity of ecological corridors increased over the same time period, with 64, 85, and 105 corridors totaling lengths of 4579.326 km, 6526.996 km, and 7015.174 km, respectively. The expansion of ecological security zones was mainly observed in the southeast part of the Loess Plateau. Overall, the ESP of the Loess Plateau saw an improvement, with the southeastern part showing better ecological security than the northwestern part. These findings hold great significance for regional ecological security evaluations and are crucial for promoting ecological management and healthy development in the Loess Plateau.

In petroleum engineering, accurately predicting particle settling velocity during various stages of a well’s life cycle is vital. This study focuses on settling velocities of both spherical and non-spherical particles in Newtonian and non-Newtonian fluids. Utilizing a dataset of 931 experimental observations, an artificial neural network (ANN) model with a 7-42-1 architecture is developed (one input layer, one hidden layer with 42 neurons, and one output layer). This model effectively incorporates particle settling orientation and the inclusion of the settling area ratio, enhancing its predictive accuracy. Achieving an average absolute relative error (AARE) of 8.51%, the ANN model surpasses traditional empirical correlations for settling velocities in both Newtonian and power-law fluids. Key influencing factors, such as the consistency index and particle equivalent diameter, were identified. This approach in ANN model construction and data analysis represents a significant advancement in understanding particle dynamics.

The Proterozoic Eon is a critical period of the Earth's evolution, and the study of its rock records in this period is important for understanding the Earth's evolution in the Precambrian. The correct interpretation of rock genesis is the basis of the study of rock geotectonics and the premise of revealing the change of earth environment based on rock records. A set of silicon-rich layered rocks generally developed at the bottom of the Changcheng System in the North China Craton, which is considered to be a set of marine quartz sandstones and siliceous rocks formed by shallow metamorphism in rift valley deposition. This paper focuses on the silica-rich layered rocks of Changzhougou Formation at the bottom of the Great Wall System exposed in Huyugou, Changping, Beijing. Through detailed field geological observations, petrological and mineral analysis of typical samples, SEM/EDS (Scanning Electron Microscopy/X-ray Spectroscopy), CL (Cathodoluminescence) imaging, in-situ LA-ICP-MS (Laser Ablation-inductively Coupled Plasma Mass Spectrometry) analysis of quartz, and petrological, micro-thermometry, muffle furnace heating-quenching experiments, and SEM/EDS, EPMA (Electron Probe Microanalysis), LRM (Laser Raman Microscopy) analysis of melt inclusions in quartz, a new understanding of the volcanic origin of the silicon-rich stratified rocks at the bottom of the Great Wall System has been proposed. The results indicate that the silicon-rich stratified rocks at the bottom of the Great Wall System include two types: clastic structures (previously defined as quartz "sandstone") and mosaic structures (previously defined as "quartzite"). The main mineral compositions are quartz and K-feldspar, with minor amounts of zircon, rutile, and other minerals. In the clastic structure rocks, quartz and K-feldspar clasts exhibit angular to subangular shapes, and K-feldspar shows no signs of clay alteration at the edges. The CL of quartz in the two types of rocks mostly shows blue-purple luminous characteristics. Additionally, the formation temperature estimated by the quartz titanium saturation thermometer is concentrated between 550 ~ 650°C, indicating characteristics of high-temperature quartz. Both types of rocks contain iron-titanium-rich two-phase melt inclusions in quartz and K-feldspar. Micro-thermometry results of the melt inclusions show that during the heating process to 1 000°C, the composition of the two-phase immiscible melt inclusions changes continuously, when the temperature reaches 1 000°C, with a color reversal occurring at about 1 050°C, and critical homogenization around 1 350°C. Muffle furnace heating-quenching experiments also confirmed that the two-phase melt inclusions in the samples quenched after heating to 1 350°C became homogeneous. SEM/EDS and EPMA results indicate that the main components of the melt inclusions are iron and titanium oxides, with the dark part being relatively rich in iron and the light part being relatively rich in titanium, and the Fe/Ti ratio of the two phases of the melt inclusions varies greatly. LRM analysis results show that both phases of the melt inclusions are amorphous. Integrating the structural characteristics of the rocks, the CL luminescence characteristics of quartz, the formation temperature estimation of quartz, and the micro-thermometry results of the melt inclusions in quartz, it is believed that the siliceous strata at bottom of the Changcheng System should be siliceous volcanic rocks and volcaniclastic rocks. This indicates that there was a large-scale siliceous volcanic activity in the North China Craton during the Paleoproterozoic, which is related to the rifting of the Columbia Supercontinent. It provides new evidence for the geological evolution of the North China Craton in the Proterozoic. The discovery of iron-titanium-rich melt inclusions in quartz also offers new perspectives on the formation of Precambrian magmatic iron and titanium deposits, particularly the enrichment mechanism of iron and titanium during the magmatic process. [ABSTRACT FROM AUTHOR]

In satellite communication systems, due to relative motion between satellites and that between satellites and the ground, the resulting Doppler frequency offset adversely affects communication synchronization. In this research, Doppler frequency offset compensation and phase offset compensation method eliminate the influence of the Doppler effect on synchronization. The proposed algorithm divides frequency estimate into two steps, coarse and precision. Finally, the corresponding frequency offset and phase offset compensation are performed. The simulation results show that the demodulated output results after frequency offset and phase offset compensation agree well with the original modulation data, indicating that the algorithm is valid and accurate.