Effects of detection-beam focal offset on displacement detection in optical tweezers

A high-resolution displacement detection can be achieved by analyzing the scattered light of the trapping beams from the particle in optical tweezers. In some applications where trapping and displacement detection need to be separated, a detection beam can be introduced for independent displacement detection. However, the detection beam focus possibly deviates from the centre of the particle, which will affect the performance of the displacement detection. In this paper, we detect the radial displacement of the particle by utilizing the forward scattered light of the detection beam from the particle. The effects of the lateral and axial offsets between the detection beam focus and the particle centre on the displacement detection are analyzed by the simulation and experiment. The results show that the lateral offsets will decrease the detection sensitivity and linear range and aggravate the crosstalk between the x-direction signal and y-direction signal of QPD. The axial offsets also affect the detection sensitivity, an optimal axial offset can improve the sensitivity of the displacement detection substantially. In addition, the influence of system parameters, such as particle radius a, numerical aperture of the condenser NAc and numerical aperture of the objective NAo on the optimal axial offset are discussed. A combination of conventional optical tweezers instrument and a detection beam provides a more flexible working point, allowing for the active modulation of the sensitivity and linear range of the displacement detection. This work would be of great interest for improving the accuracy of the displacement and force detection performed by the optical tweezers.Comment: 10 pages,11 figure

Mapping current trends and hotspots in myasthenia gravis from 2003 to 2022: a bibliometric analysis

IntroductionResearch on myasthenia gravis (MG) has undergone rapid development in recent years. This article aimed to elucidate the characteristics of MG publications over the past 20 years and analyze emerging trends using bibliometric methods.MethodsInformation on MG articles was obtained from the Web of Science Core Collection and stored in Excel for quantitative analyses. Bibliometric analyses were performed using CiteSpace and VOSviewer to visualize publications according to countries/regions, institutions, journals, and authors.ResultsA total of 3,610 publications were included in the analysis. The USA had the highest number of publications (NP) and H-index. Among the institutions, the University of Oxford had the highest NP, followed by the University of Toronto and Duke University. Close cooperation was observed among countries and institutions. The most productive author was Renato Mantegazza, followed by Jan J. Verschuuren, and Amelia Evoli. Muscle & Nerve published the most articles on MG, followed by the Journal of Neuroimmunology and Neuromuscular Disorders. The keyword with the highest strength is “neuromuscular transmission,” followed by “safety” and “rituximab.” Co-citation analysis includes 103 publications cited at least 65 times, categorized into four clusters. Additionally, 123 keywords cited more than 40 times were analyzed and divided into five clusters.ConclusionThis bibliometric analysis shows the framework of research over the past 20 years by mapping the scholarly contributions of various countries or regions, institutions, journals, and authors in MG. The analysis also explores future trends and prospective directions, emphasizing individualized treatment based on subtypes, novel immunotherapeutic approaches, and thymectomy

UCP1 alleviates renal interstitial fibrosis progression through oxidative stress pathway mediated by SIRT3 protein stability

Abstract Background Renal interstitial fibrosis is a common pathway for the progressive development of chronic renal diseases (CKD) with different etiology, and is the main pathological basis leading to end-stage renal disease. Although the current research on renal interstitial fibrosis is gradually deepening, the diagnosis and treatment methods are still very lacking. Uncoupling protein 1 (UCP1) is a nuclear encoded protein in mitochondria inner membrane and plays an important role in regulating energy metabolism and mitochondrial homeostasis. However, the biological significance of UCP1 and potential regulatory mechanisms in the development of CKD remain unclear. Methods Unilateral ureteral obstruction (UUO) model was used to construct the animal model of renal fibrosis, and TGF-β1 stimulation of HK2 cells was used to construct the vitro model of renal fibrosis. UCP1 expression was detected by Western blot, immunoblot analysis and immunohistochemistry. UCP1 was upregulated by UCP1 overexpressing lentivirus and UCP1 agonist CL316243. Western blot and immunofluorescence were used to detect epithelial mesenchymal transition (EMT)-related markers, such as collagen I, fibronectin, antioxidant enzyme SOD2 and CAT. Reactive oxygen species (ROS) production was detected by ROS detection kit. SIRT3 knockdown was performed by siRNA. Results This study presents that UCP1 is significantly downregulated in patients with renal fibrosis and UUO model. Further studies discover that UCP1 overexpression and CL316243 treatments (UCP1 agonists) reversed EMT and extracellular matrix (ECM) accumulation in renal fibrosis models in vivo and in vitro. Simultaneously, UCP1 reduced the ROS production by increasing the stability of SIRT3. When SIRT3 was knocked down, the production of ROS decreased. Conclusions Elevating the expression of UCP1 can inhibit the occurrence of oxidative stress by stabilizing SIRT3, thereby reducing EMT and ECM accumulation, and ultimately alleviating renal interstitial fibrosis. It will provide new instructions and targets for the treatment of CKD

Expanded Continuous Test for Comprehensive Utilization of a Rare Earth and Associated Fluorite Resources in Henan

This is an essay in the field of mineral processing engineering. In this paper, a rare earth and associated fluorite resource in Henan Province was studied. Based on the results of process mineralogy and small beneficiation experiments, an extended continuous test with a capacity of 60 kg/h was carried out. Through chemical analysis and AMICS microscopic identification, it was found that the content of REO and CaF2 was 1.53% and 18.22%, respectively. The target minerals for REO separation were hamartite and parisite. The process of "mixed flotation - separation flotation of REO and fluorite " was used to recover REO and fluorite from ores. On this basis, the extended continuous test was carried out, and finally obtained the rare earth concentrate with REO grade of 52.54% and recovery rate of 51.15%, and the fluorite concentrate with a CaF2 grade of 94.76% and recovery rate of 60.80%. The concentrate product index was good, and comprehensive recovery and utilization of REE associated fluorite were preliminarily realized. It is helpful to provide technical support for the production of enterprises and provide a basis for the comprehensive development and utilization of the same type of rare earth and co-associated resource deposits

Experimental Study on the Recovery of Rare Earth from a Low Grade Rare Earth Tailings in Sichuan

This is an essay in the field of mineral processing engineering. This study focuses on a rare earth tailing in Sichuan province. Mineralogy research shows that the distribution minerals of rare earth metal composition in the tailing are relatively consistent and the main minerals are bastnasite and synchisite. For the reason that the low grade of rare earth in the sample, only contains 1.06%, the gravity separation process is adopted to preconcentrate the rare earth minerals in the tailing to reduce the cost of processing. The floating-magnetic process is carried out on the preconcentration product with a self-developed mixed collector and water glass as inhibitor. The combined flotation process of "one roughing-one sweeping-three cleanings" and high intensity magnetic separation could obtain a rare earth concentrate with REO grade of 53.63% and recovery of 70.54% which successfully achieves the recycling rare earth from the low-grade rare earth tailings

Mineral Features and Current Extraction Situation of Rare Earth Resources in Deep-sea Deposit

This is an essay in the field of mining engineering. Deep-sea rare earth rich deposit, as a potential rare earth resource, are an important supplement to land rare earth resources and may become one of the first deep-sea minerals to be exploited. In this paper, four deep-sea REE rich deposit (REE rich deposits in the western Pacific Ocean, the southeast Pacific Ocean, the middle and east Pacific Ocean, and the Middle Indian Ocean basin-Wharton Basin.) are analyzed. This paper summarizes the basic resource characteristics of deep-sea rare earth rich deposit (such as large total reserves, large distribution differences, and the main occurrence mineral is biological apatite), and reviews two methods (acid leaching-extraction separation technology and separation-flotation method) used in the separation and extraction of deep-sea REE. The result shows that the acid leaching-extraction separation technology has the disadvantages of low recovery of REE and excessive acid consumption. The separation of sediment samples before flotation operation can achieve efficient enrichment of REE in deposit under the condition of low acid consumption, which is an important development direction to separate and extract REE resources from deep-sea REE rich deposit. Based on this, it is suggested to strengthen the research and development related to efficient classification of deep-sea REE rich deposit resources and in-situ mining and leaching technology in the future

Application of artificial intelligence-assisted compressed sensing combined with three types of fat-suppressed T₂WI techniques

Objective To explore the advantages of artificial intelligence-assisted compressed sensing （ACS） combined with three types of fat-suppressed T2WI techniques in image quality， scanning time and scheme selection. Methods In 30 patients with low back pain who underwent conventional lumbar magnetic resonance imaging （MRI） plain scan， ACS combined with 5 groups of sagittal （SAG） fat-suppressed T2WI sequences were added to original examination sequence. Frequency-selective fat saturation （FS）， water-fat separation （WFI） and short tau inversion recovery （STIR） techniques were employed. ACS-SAG-T2WI-FS （group A， n=30）， Acs-SAG-T2WI-WFI （group B， n=30）， ACS-SAG-STIR （group C n=30）， SAG-T2WI-FS （group D， n=30）， SAG-T2WI-WFI （group E， n=30） and SAG-STIR sequences （group F， n=30） were employed. Objective evaluation indicators of signal-to-noise ratio （SNR） and contrast-to-noise ratio （CNR） and subjective evaluation by two radiologists were carried out to assess the effect. Results The SNR and CNR of the fourth vertebra， the fourth and fifth intervertebral discs and the same spinal cord in group A were higher than those in group D. The SNR and CNR of the fourth vertebra， the fourth and fifth intervertebral discs， and the same spinal cord in group B were higher than those in group E. The SNR and CNR of the fourth vertebra， the fourth and fifth intervertebral discs， and the same spinal cord in group C were higher compared with those in group F （all P < 0.01）. The imaging time in group A was shortened by 13.2% compared with that in group D. The imaging time in group B was reduced by 8.9% compared with that in group E. The imaging time in group C was reduced by 12.4% compared with that in group F （all P < 0.01）. The subjective scores by two radiologists for groups A， B and C were significantly higher than those in groups D， E and F （all P < 0.01；The scores of the two physicians were consistent， Kappa=0.972， P <0.01）. Conclusions The combination of ACS and three types of fat-suppressed T2WI techniques （FS， WFI and STIR） is superior to use of fat-suppressed T2WI techniques alone. ACS-SAG-T2WI-FS sequence is recommended with the shortest imaging time and the highest image quality. ACS-SAG-T2WI-WFI sequence provides multiple groups of phase images， and the time advantage difference is the second choice. ACS-SAG-STIR sequence has the most stable fat-suppression capability， which can be used as the last option

Selective Adsorption of Sodium Silicate on the Surface of Bastnaesite and Fluorite in Salicylhydroxamic Acid System under Alkaline Conditions

During the flotation separation process of bastnaesite, it is difficult to separate bastnaesite from fluorite effectively. In this present study, sodium silicate (SS) can effectively improve the flotation separation effect of bastnaesite and fluorite in salicylhydroxamic acid (SHA) systemasa. Through relevant analyses, such as Zeta potential measurements, adsorption capacity tests, Fourier transform infrared (FTIR) spectroscopic analyses and X-ray photoelectron spectroscopy (XPS) tests, the selective suppressor of SS on fluorite was proven. At pH 10, the single mineral flotation results show that with the increase of SS dosage, the flotation recovery of fluorite rapidly decreases from 61.5% to 35.31%, while the flotation rate of bastnaesite is still high (recovery is 80.02%). Then, the experiment of artificial mixed ore proved that the flotation separation of fluorite and bastnaesite was effective under the appropriate dosage of inhibitor. The results of potentiodynamic measurement and an adsorption capacity test showed that the SiOOH3− structure of SS more easily reacted with fluorite, which further prevented the adsorption of SHA on the fluorite surface. FTIR test results and XPS analysis further showed that SS had a strong binding effect with the Ca site on the fluorite surface, but a weak binding effect with the Ce site on the bastnaesite surface. Consequently, SS can be used as an effective inhibitor in the flotation separation of fluorite and bastnaesite

Effects of detection-beam focal offset on back-focal-plane displacement detection

High-resolution displacement detection can be achieved by analyzing the scattered light of the trapping beams from the particle in optical tweezers. In some applications where trapping and detecting beams must be separated, a detecting beam can be introduced for independent displacement measurement. However, the detecting beam focus possibly deviates from the center of the particle, which will affect the performance of displacement detection. Here, we detect the displacement of the particle by utilizing the forward scattered light of the detection beam from the particle. The effects of the lateral and axial offsets between the detection beam focus and the particle center on displacement detection are analyzed by the simulation and experiment. These results show that the lateral offsets will decrease the detection sensitivity and linear range. Moreover, it aggravates the crosstalk between the x-direction signal and the y-direction signal of the quadrant photodiode. Besides, the axial offsets also affect the detection sensitivity. More interestingly, an optimal axial offset can improve the sensitivity of displacement detection substantially. In addition, the influence of system parameters, such as particle radius a, numerical aperture of the condenser NAc, and numerical aperture of the objective NAo, on the optimal axial offset is also discussed. This work not only provides ideas for improving the performance of precision measurement by the method of forward scattered light detection but also expands the application of this method in fundamental physics

Current state of research on exercise for the treatment of myasthenia gravis: A scoping review

Objective: To provide a comprehensive overview of existing evidence, research gaps, and future research priorities concerning the treatment of myasthenia gravis (MG) using exercise therapies. Method: Clinical studies on exercise treatment for MG were searched in nine databases to conduct a scoping review. Two independent researchers screened the literature and comprehensively analyzed the characteristics and limitations of the included articles. Results: A total of 5725 studies were retrieved, of which 24 were included. The included studies were conducted in 16 different countries/regions and 456 patients were enrolled. Study designs included both interventional and observational studies. Exercise interventions included aerobic exercise, resistance exercise, balance training, and stretch training, and are typically administered in conjunction with medication, usual care, or some other interventions. The intensity, frequency, and duration of exercise interventions varied hugely among studies. Six-minute walk test, adverse events, muscle strength, MG quality of life-15 scale, forced vital capacity, quantitative MG scale, and MG activities of daily living scale were the most frequently used outcomes. All studies reported results in favor of the efficacy and safety of exercise in MG, and exercise-related adverse events were reported in two studies. Conclusion: This scoping review provides an overview of the evidence concerning exercise treatment for MG. Key gaps in evidence include a limited number of participants, complex interventions, variability in outcome selection, and insufficient reporting in publications. The promotion of exercise treatment for MG still encounters several obstacles. A larger population, rigorous study design and conduction, standardized interventions and outcomes, and standardized reporting are essential