Search

Virtual reality technology, also known as virtual reality or psychic technology, is a new practical technology developed in the 20th century. Virtual reality technology includes computer, electronic information, simulation technology, its basic realization is based on computer technology, the use and integration of three-dimensional graphics technology, multimedia technology, simulation technology, display technology, servo technology and other high-tech latest development achievements, With the help of computer and other equipment to produce a realistic three-dimensional vision, touch, smell and other sensory experience of the virtual world, so that people in the virtual world have a sense of being in the scene. With the continuous development of social productivity and science and technology, the demand for VR technology is increasingly strong in all walks of life. VR technology has also made great progress and gradually become a new field of science and technology.

Diffusion tensor imaging (DTI) parameters correlate with muscle fiber composition, but it is unclear how these relate to in vivo contractile function.To determine the relationship between DTI parameters of the vastus lateralis (VL) and in vivo knee extensor contractile.Thirteen healthy, premenopausal women underwent magnetic resonance imaging of the mid-thigh to determine patellar tendon moment arm length and quadriceps cross-sectional area. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of the VL were determined using diffusion tensor imaging (DTI). Participants underwent an interpolated twitch (ITT) experiment before and after a fatiguing concentric-eccentric isokinetic knee extension (60°·sMD and RD were moderately correlated with peak twitch force and rate of force development. FA and AD were moderately inversely related to percent change in MVIC following exercise.MD and RD are associated with in vivo quadriceps twitch properties but not voluntary strength, which may reflect the mechanical properties of constituent fiber types. FA and AD appear to relate to MVIC strength following fatiguing exercise.

Taking the key components of the umbrella wind turbine regulating mechanism as the research object, the main stress concentration parts were determined by numerical simulation, and the strength of the key components was checked. Through the wind tunnel test, the variation of the stress on the key components of the adjustment mechanism with the shrinkage angle of the umbrella wind turbine under the actual operating conditions was tested. The results show that the stress on the connecting rod and the small hub increases first and then decreased with the increase of the shrinkage angle, and both reach the maximum stress under the working condition of 45°. The stress of the large hub decreased with the increase of the shrinkage angle. The safety and reliability of the power regulating mechanism of the umbrella wind turbine was verified by numerical simulation and wind tunnel test, which laid a research foundation for the subsequent structural optimization and improvement of the umbrella wind turbine.

Background: Abnormal blood lipids are associated with cognitive impairment and amyloid-β (Aβ) deposition in the brain. However, the effects of statins on Alzheimer’s disease (AD) have not been determined. Objective: Considering that plasma Aβ are related to Aβ deposition in the brain, we investigated the effects of simvastatin on plasma Aβ transport. Methods: This was a randomized, double-blind, placebo-controlled trial. One hundred and twenty patients with hyperlipidemia were randomly assigned to receive 40 mg of simvastatin per day or matching placebo for 12 weeks (sixty patients per group). Plasma Aβ, sLRP1, sRAGE, and lipid levels were measured at baseline and at the 6-week and 12-week visits. Results: The ITT database ultimately included 108 participants (placebo group: n = 53; simvastatin group: n = 55) and 64 (59.3%) were women, ranging in age from 45 to 75 years (mean 57.2±6.9 years). Multiple linear regression analysis showed that, after 12 weeks of follow-up, compared with the placebo group, ΔAβ42 levels (the change of Aβ42 levels from baseline at week 12) increased more and ΔsRAGE levels decreased more in the simvastatin group (Aβ42: β= 5.823, p = 0.040; sRAGE: β= –72.012, p = 0.031), and a significant negative association was found between ΔAβ42 and ΔsRAGE levels (β= –0.115, p = 0.045). In addition, generalized estimation equation analysis showed that triglycerides levels were negatively correlated with Aβ40 (β= –16.79, p = 0.023), Aβ42 (β= –6.10, p = 0.001), and sRAGE (β= –51.16, p = 0.003). Conclusion: Daily oral simvastatin (40 mg/day) in patients with hyperlipidemia for 12 weeks can significantly increase plasma Aβ42 levels compared with placebo, which was associated with reduced triglycerides and sRAGE levels, indicating that statins may affect plasma Aβ transport.

Nano-magnesium oxide (MgO) can be used as an expansion agent for cement-based materials, but little is known about the influence of nano-magnesium oxide on the mechanics, microstructure and expansion stability of cement materials. The influence of nano-magnesium oxide on the consistency, fluidity, porosity, dry and wet densities, mechanical properties and microstructures of cement-based materials was researched in this study. The results show that the compressive strength and flexural strength of the cement mortar test block containing nano-magnesium oxide particles increase and are higher than those of the control cement mortar test block at any time. The addition of nano-magnesium oxide increases the mechanical strength of the cement mortar block, and the strengthening effects are most obvious in the early stage of maintenance. When the curing age is 28 days and the nano-magnesium oxide content is 1.5%, the compressive strength and flexural strength of the modified cement mortar test block are the best. Fourier transform infrared spectroscopy and scanning electron microscopy show that the expansion effect of nano-magnesium oxide makes the microstructure of cement-based materials denser and more uniform. This paper also discusses the influence mechanism of nano-magnesium oxide on cement-based materials, which provides a reference for the application of nano-magnesium oxide in cement-based materials.

Chirality is essential in nearly all biological organization and chemical reaction but is rarely considered due to technical limitations in identifying L/D isomerization. Using OmpF, a membrane channel from E. coli with an electrostatically asymmetric constriction zone, allows discriminating chiral amino acids in a single peptide. The heterogeneous distribution of charged residues in OmpF causes a strong asymmetric electrostatic field at the constriction. This asymmetry forces the sidechains of the peptides to specific orientations within OmpF, causing distinct ion current fluctuations. Using a statistical analysis of the respective ion current variations allows distinguishing the presence and position of each chiral amino acid. To explore potential applications, the disease-related peptide β-Amyloid, and its D-Asp1 isoform, as well as a mixture of the Icatibant peptide drug (HOE 140) and its D-Ser7 mutant, have been discriminated. Both chiral isomers were not applicable to be distinguished by mass spectrum approaches. These findings highlight a novel sensing mechanism for identifying single amino acids in single peptides and even for achieving single-molecule protein sequencing.

Purpose Hotel employees’ occupational stigma is often overlooked. Exploration of hotel employees’ occupational stigma representations, perception pathways and destigmatization provides an empirical basis for positive organizational behavior and psychology in the hotel industry. Therefore, this study aims to better understand the mechanism underlying inherent of occupational stigma. Design/methodology/approach This study adopts a five-factor narrative analysis involving stigma narrative interviews with a purposed sampling of hotel employees (n = 18). Based on occupational stigma and resource conservation theories, this study designed a five-factor narrative analysis structure chart as the basis for data analysis. Findings Findings indicate the existence of four quadrants of perceived occupational stigma attribute distribution, two paths of perceived occupational stigma formation and a more systematic occupational destigmatization mechanism path. Research limitations/implications The occupational destigmatization path and countermeasures proposed in this study can resolve talent drain and eliminate stereotyping in the hotel industry, which promote the industry’s rapid recovery and sustainable healthy development, providing the practical management guidelines for public communication via social media, and offer practical significance for existing hotel human resource management in modules such as organizational culture and training. Originality/value This study broadens investigations of occupational stigma in a single, static context and explains the relationship between hotel employees’ stigma perceptions and destigmatization paths. Further, the mechanism of emotional energy distribution on spatial stigma was identified. These results have practical implications for organizational culture, training and employee care in hotel human resource management.

Surgical brain injury (SBI) is unavoidable in neurosurgery, and could aggravate secondary brain injury. Post-brain injury, multiple inflammatory factors are released, resulting in neuroinflammation and cell apoptosis, with subsequent brain edema and nerve function injury. TREM2, an immune protein mainly expressed in microglia, is an important link for nerve cells to participate in the inflammatory response. TREM2 and nuclear factor кB (NF-кB) are indeed closely associated with the release of inflammatory cytokines following brain injury. This work aimed to determine the inflammatory function of TREM2 in SBI, and to investigate whether TREM2 regulates interleukin-1 beta (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) release through the NF-кB p65 signaling pathway. We established a rat model of SBI, and performed Western blotting (WB), immunofluorescence (IF) and enzyme-linked immunosorbent assay (ELISA) for further analysis. Next, brain edema and neurological score analyses were performed. Finally, whether TREM2 regulating NF-кB p65 signaling affects blood-brain barrier (BBB) permeability and nerve cell apoptosis was examined. We found that post-SBI, TREM2 was upregulated, and inflammation and brain injury were aggravated. After TREM2 downregulation, NF-кB p65 production, inflammation and brain injury were enhanced, suggesting that TREM2 may play a protective role by inhibiting NF-кB p65 production after SBI. Overall, these findings suggest that TREM2 in SBI may have protective effects on postoperative nerve and BBB damage, possibly in part via the NF-κB p65 pathway.

Global Navigation Satellite System-Reflectometry (GNSS-R) technique has been used to obtain sea surface height (SSH) since the 1990s. Due to the short wavelengths and low power of GNSS signals, the continuously tracked carrier phase measurements of reflected signals are usually unavailable for sea surfaces with big roughness, varying over space and time. Under high sea states, the phase difference cannot be well retrieved from carrier phase measurements, especially for the signals with high elevation angles. To overcome these shortcomings related to temporal incoherence, we propose an improved algorithm to extract the combined interferometric phase difference measurements between direct and reflected signals. We improve the configuration of GNSS-R altimetry software-defined receiver (SDR) by reconstructing ‘clean’ direct signals to compute phase differences between direct and reflected signals. The interferometric phase differences are combined in the complex domain and the resulting interferometric signal is refined through open-loop tracking with 60-s coherent integration before the phase difference measurements are extracted, without tracking their respective carrier phase measurements in advance. In order to verify our method, a coastal experiment under different sea conditions was conducted. Raw intermediate frequency data of Quasi-Zenith Satellite System were collected and processed by SDR to compute the path delay measurements of L1 and L5. Under high sea states, the phase delay measurements of L1 and L5 were random over time, while phase delay can still be well recovered based on the proposed method even in the case of high elevation angles. The altimetry solutions were compared with the in situ observations from a radar altimeter instrument. The results show that centimeter-level altimetry accuracy can be achieved under high sea states using the proposed method The same SDR and method are applied in the shipborne altimetry experiment, the interferometric phase observations are successfully extracted on both ship motion and statics. Also, the integer ambiguity in the interferometric phase observations is well estimated. The differences in the SSH measurements between different satellites is at centimeter level. The coastal and shipborne experiments demonstrate that the dual-antenna GNSS-R phase altimetry technique can be used for low-cost tide gauges on different platforms to monitor sea levels.Acknowledgments: This work was supported by Natural Science Foundation of China (42192534) and Key Research and Development Program of Shandong Province (Major Technological Innovation Project, 2021ZDSYS01).

Alzheimer’s disease (AD) is a complex neurodegenerative disorder that affects millions of people worldwide. Despite decades of research, the underlying molecular and cellular changes of AD remain unresolved, especially in terms of the spatial structure of gene expression changes that correlates with pathology, e.g. amyloid beta (A-beta) plaques. Recent advances in imaging-or sequencing-based single-cell spatial transcriptomics have allowed a systematic dissection of molecular and cell architectures in the brain and other tissues. In this study, we employed the recently developed Stereo-seq technology to spatially profile the whole-genome transcriptomics in the 5xFAD mouse model and established the methodology to analyze the specific neuronal transcriptomic changes spatially correlated with amyloid pathology at single cell resolution. More specifically, we developed a pipeline for integrative image- and non-image-based cell segmentation, VoxelMorph-based non-linear alignment, and Unet-based object detection to achieve reliable transcriptomics analysis at the single-cell resolution, and investigated the spatial relationship between diverse neuronal clusters and A-beta depositions. This work has demonstrated the potential of using the Stereo-seq technology as a powerful tool to investigate AD and other complex neurological disorders.

Cholecystokinin receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on CCK receptors [90]) are activated by the endogenous peptides cholecystokinin-8 (CCK-8), CCK-33, CCK-58 and gastrin (gastrin-17). There are only two distinct subtypes of CCK receptors, CCK1 and CCK2 receptors [64, 124], with some alternatively spliced forms most often identified in neoplastic cells. The CCK receptor subtypes are distinguished by their peptide selectivity, with the CCK1 receptor requiring the carboxyl-terminal heptapeptide-amide that includes a sulfated tyrosine for high affinity and potency, while the CCK2 receptor requires only the carboxyl-terminal tetrapeptide shared by each CCK and gastrin peptides. These receptors have characteristic and distinct distributions, with both present in both the central nervous system and peripheral tissues.

The neural circuits governing the induction and progression of neurodegeneration and memory impairment in Alzheimer’s disease (AD) are incompletely understood. The mammillary body (MB), a subcortical node of the medial limbic circuit, is one of the first brain regions to exhibit amyloid deposition in the 5xFAD mouse model of AD. Amyloid burden in the MB correlates with pathological diagnosis of AD in human postmortem brain tissue. Whether and how MB neuronal circuitry contributes to neurodegeneration and memory deficits in AD are unknown. Using 5xFAD mice and postmortem MB samples from individuals with varying degrees of AD pathology, we identified two neuronal cell types in the MB harboring distinct electrophysiological properties and long-range projections: lateral neurons and medial neurons. lateral MB neurons harbored aberrant hyperactivity and exhibited early neurodegeneration in 5xFAD mice compared with lateral MB neurons in wild-type littermates. Inducing hyperactivity in lateral MB neurons in wild-type mice impaired performance on memory tasks, whereas attenuating aberrant hyperactivity in lateral MB neurons ameliorated memory deficits in 5xFAD mice. Our findings suggest that neurodegeneration may be a result of genetically distinct, projection-specific cellular dysfunction and that dysregulated lateral MB neurons may be causally linked to memory deficits in AD.

Aiming at the problems of blurring and distortion of traditional patterns, an enhancement method to improve resolution and contrast is proposed.First, the discrete wavelet transform, stationary wavelet transform, and interpolation algorithm are used to obtain high-resolution images of traditional patterns. Then, the improved singular value matrix coefficients and the reconstructed gamma function are used to enhance the image contrast to obtain high-resolution and contrast-enhanced patterns. The experimental results show that the evaluation indexes such as mean square error, peak signal-to-noise ratio, and structural similarity corresponding to this method are improved compared with other comparison methods. It can effectively improve the quality of traditional patterns and is of great significance to the research on the restoration and protection of traditional patterns.

The supplementary figures included in this file describe the distribution of gap time from first to second primary by proband status(Fig 1), by cancer type (Fig 2) and by sex (Fig 3).

This supplementary tables file contains information in the TP53 germline mutations that were sequenced in each MDA cohort.

Li-Fraumeni syndrome (LFS) is a rare autosomal dominant disorder associated with TP53 germline mutations and an increased lifetime risk of multiple primary cancers (MPC). Penetrance estimation of time to first and second primary cancer within LFS remains challenging because of limited data and the difficulty of characterizing the effects of a primary cancer on the penetrance of a second primary cancer. Using a recurrent events survival modeling approach that incorporates a family-wise likelihood to efficiently integrate the pedigree structure, we estimated the penetrance for both first and second primary cancer diagnosis from a pediatric sarcoma cohort at MD Anderson Cancer Center [MDACC, Houston, TX; number of families = 189; single primary cancer (SPC) = 771; and MPC = 87]. Validation of the risk prediction performance was performed using an independent MDACC clinical cohort of TP53 tested individuals (SPC = 102 and MPC = 58). These findings showed that an individual diagnosed at a later age was more likely to be diagnosed with a second primary cancer. In addition, TP53 mutation carriers had a HR of 1.65 (95% confidence interval, 1.1–2.5) for developing a second primary cancer versus SPC. The area under the ROC (AUC) curve for predicting individual outcomes of MPC versus SPC was 0.77. In summary, we provide the first set of penetrance estimates for first and second primary cancer for TP53 germline mutation carriers and demonstrate its accuracy for cancer risk assessment.Significance:These findings present an open-source R package LFSPRO that could be used for genetic counseling and health management of individuals with LFS as it estimates the risk of both first and second primary cancer diagnosis.See related article by Shin et al., p. 354

During development, embryonic patterning systems direct a set of initially uncommitted pluripotent cells to differentiate into a variety of cell types and tissues. A core network of transcription factors, such as Zelda/POU5F1, Odd-paired (Opa)/ZIC and Ocelliless (Oc)/OTX, are conserved across animals. While Opa is essential for a second wave of zygotic activation after Zelda, it is unclear whether Opa drives head cell specification past gastrulation onset, in theDrosophilaembryo. Our hypothesis is that Opa and Oc are interacting with distinct cis-regulatory regions for shaping cell fates in the embryonic head. Using super-resolution microscopy and epigenomic meta-analysis of single cell RNAseq datasets we find thatopa’s andoc’s overlapping expression domains are dynamic in the head region, with both factors being simultaneously transcribed at the blastula stage. However, analysis of single-embryo RNAseq data reveals a subgroup of Opa-bound genes to be Opa-independent in the cellularized embryo. Interrogation of these genes against Oc ChIPseq combined with in situ data, suggests that Opa is competing with Oc for the regulation of a subgroup of genes later in gastrulation. Specifically, we find that Oc binds to late, head-specific enhancers independently and activates them in a head-specific wave of zygotic transcription, suggesting distinct roles for Oc in the blastula and gastrula stages.