基于改进Alpha Shape算法的点云数据岛屿边界提取

针对机载LiDAR点云的岛屿岸线提取过程复杂、附属岛屿岸线难以提取等问题,提出一种基于改进Alpha Shape算法的点云数据岛屿边界提取方法。首先利用布料模拟滤波算法剔除非岛屿点云数据,通过欧式聚类进行不同岛屿的提取,再将岛屿点云数据投影至二维平面,并根据岛屿点云构建格网。在此基础上使用自适应Alpha Shape算法,对提取出的岛屿点云进行边界提取,即可得到岛屿的岸线轮廓。选取新西兰的玛提尤/萨姆斯岛作为研究区域,并将本文算法与Alpha Shape算法进行对比,结果表明:本文算法提取岛屿边界点云的精准度为97.78%,可以准确地提取岛屿岸线,为海岛规划提供参考。

Alpha7 nicotinic receptors as potential theranostic targets for experimental stroke

Inflammatory reflex and cholinergic anti-inflammatory pathway:Innate immune system triggers a local inflammatory response following an injury or a pathogen invasion.Likewise,this inflammatory response is limited by rapid,localized,and adaptive anti-inflammatory responses which are crucial for maintaining homeostasis.Hence,the loss of these responses converts a limited and protective inflammatory response into an excessive and harmful response.Anti-inflammatory responses are integrated into the central nervous system,since the central nervous system accumulates information about harmful events,activates defenses,and builds memory for survival.At the same time,it has been demonstrated that hypothalamic neuronal signaling can be altered by inflammation in peripheral tissues.Additionally,immune cells release neuropeptides and neurotransmitters such as acetylcholine(ACh),the main neurotransmitter of the parasympathetic autonomic nervous system,evidencing the communication between the immune and nervous systems(Tracey,2002).

Alpha-synuclein in mitochondrial dysfunction:opportunities or obstacles

Recent work suggests a link betweenα-synuclein(α-syn)and mitochondrial dysfunction;however,the mechanisms of howα-syn influences mitochondrial function are still unclear.Most notably,whetherα-syn plays a direct role during mitochondrial function and/or whether diseasedα-syn-mediated mitochondrial dysfunction is a potential modifiable risk factor in Parkinson’s disease(PD)is unknown.To date,mutations in more than eight genes cause familial PD(fPD)and have functions in diverse pathways including synaptic homeostasis,mitochondria maintenance,autophagy/lysosome,and ubiquitin-proteasome pathways.

Numerical study of alpha particle loss with toroidal field ripple based on CFETR steady-state scenario

Effects of plasma equilibrium parameters on the alpha particle loss with the toroidal field ripple based on the CFETR steady-state scenario have been numerically investigated by the orbit-following code GYCAVA. It is found that alpha particle losses decrease and loss regions become narrower with the plasma current increasing or with the magnetic field decreasing. It is because the ripple stochastic transport and the ripple well loss of alpha particle are reduced with the safety factor decreasing. Decrease of the plasma density and temperature can reduce alpha particle losses due to enhancement of the slowing-down effect. The direction of the toroidal magnetic field can significantly affect heat loads induced by lost alpha particle. The vertical asymmetry of heat loads induced by the clockwise and counter-clockwise toroidal magnetic fields are due to the fact that the ripple distribution is asymmetric about the mid-plane, which can be explained by the typical orbits of alpha particle. The maximal heat load of alpha particle for the clockwise toroidal magnetic field is much smaller than that for the counter-clockwise one.

Hydrographic Characteristics and Oceanic Heat Flux in the Upper Arctic Ocean over the Alpha Ridge Observed by the DTOP Platform in 2018 and 2021

In 2018 and 2021,the Drift-Towing Ocean Profilers(DTOP)provided extensive temperature and salinity data on the upper 120m ocean through their drifts over the Alpha Ridge north of the Canada Basin.The thickness and temperature maximum of Alaska Coastal Water(ACW)ranged from 20m to 40m and-1.5℃to-0.8℃,respectively,and the salinity generally maintained from 30.2 to 32.5.Comparison with World Ocean Atlas 2018’s climatology manifested a 40m-thick and warm ACW roughly ex-ceeding the temperature maximum by 0.4–0.5℃in June–August 2021.This anomalously warm ACW was highly related to the ex-pansion of the Beaufort Gyre in the negative Arctic Oscillation phase.During summer,the under-ice oceanic heat flux F_(w)^(OHF)was elevated,with a maximum value of above 25Wm^(-2).F_(w)^(OHF)was typically low in the freezing season,with an average value of 1.2Wm^(-2).The estimates of upward heat flux contributed by ACW to the sea ice bottom F_(w)^(OHF)were in the range of 3–4Wm^(-2)in June–August 2021,when ACW contained a heat content of more than 80MJm^(-2).The heat loss over this period was driven by a weak stratification upon the ACW layer associated with a surface mixed layer(SML)approaching the ACW core.After autumn,F_(w)^(OHF)was reduced(<2 Wm^(-2))except during rare events when it elevated F_(w)^(OHF)slightly.In addition,the intensive and widespread Ekman suction,which created a violent upwelling north of the Canada Basin,was largely responsible for the substantial cooling and thinning of the ACW layer in the summer of 2021.

Gross Alpha and Beta Activities and Related Lifetime Risks Assessment Due to Ingestion of Drinking Water from Different Sources in the District of Abidjan, Cote d’Ivoire

Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMaticTM) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan.

Liver disease in patients with transfusion-dependentβ-thalassemia:The emerging role of metabolism dysfunction-associated steatotic liver disease

In this Editorial,we highlight the possible role that metabolism dysfunction-associated steatotic liver disease(MASLD)may play in the future,regarding liver disease in patients with transfusion-dependent β-thalassemia(TDBT).MASLD is characterized by excessive accumulation of fat in the liver(hepatic steatosis),in the presence of cardiometabolic factors.There is a strong correlation between the occurrence of MASLD and insulin resistance,while its increased prevalence parallels the global epidemic of diabetes mellitus(DM)and obesity.Patients with TDBT need regular transfusions for life to ensure their survival.Through these transfusions,a large amount of iron is accumulated,which causes saturation of transferrin and leads to the circulation of free iron molecules,which cause damage to vital organs(primarily the liver and myocardium).Over the past,the main mechanisms for the development of liver disease in these patients have been the toxic effect of iron on the liver and chronic hepatitis C,for which modern and effective treatments have been found,resulting in successful treatment.Additional advances in the treatment and monitoring of these patients have led to a reduction in deaths,and an increase in their life expectancy.This increased survival makes them vulnerable to the onset of diseases,which until recently were mainly related to the non-thalassemic general population,such as obesity and DM.There is insufficient data in the literature regarding the prevalence of MASLD in this population or on the risk factors for its occurrence.However,it was recently shown by a study of 45 heavily transfused patients with beta-thalassemia(Padeniya et al,BJH),that the presence of steatosis is a factor influencing the value of liver elastography and thus liver fibrosis.These findings suggest that future research in the field of liver disease in patients with TDBT should be focused on the occurrence,the risk factors,and the effect of MASLD on these patients.

AlphaFold 3将助力药物研发

2024年5月8日出版的《自然》报道了AlphaFold 3能以较高准确率预测蛋白质与其他生物分子相互作用的结构。AlphaFold 3是该人工智能模型的最新迭代,准确率与之前的专用工具相比显著提升,该模型由谷歌DeepMind和Isomorphic实验室的团队研发。这一最新模型能够预测蛋白质数据库(Protein Data Bank)内几乎所有分子类型复合物的结构。

Alpha稳定分布噪声下基于轻量级网络的自动调制识别技术

自动调制识别在无线通信领域发挥了巨大作用。多数研究中假设的加性高斯白噪声信道已不再满足实际信道环境的准确描述。实际中,由于闪电、雷暴、多用户干扰、设备故障等原因,信道环境中广泛存在Alpha稳定分布噪声。因此对其开展研究更符合实际且具有挑战性。该文针对Alpha稳定分布噪声提出了一种预处理联合轻量级网络的调制识别方法。首先,通过对数域映射及阈值限制对接收信号进行预处理,抑制由Alpha稳定分布噪声带来的尖锐脉冲将信号幅度控制到合理范围;然后,提出一种基于Ghost模块的轻量级网络来完成信号的调制识别分类任务。实验结果表明,与现有的CLDNN(Convolutional Long Short-term Deep Neural Network)、CNN(Convolutional Neural Network)、ResNe(t Residual Network)相比,本文所提方法具有较高的识别准确率及较低的计算复杂度。

改进Alpha Shapes和快速凸壳算法的SVM故障诊断

现有的基于凸壳的支持向量机(SVM)算法处理机械装备产生的大规模原始数据时间太长。针对这一问题,通过结合轮廓提取算法(Alpha Shapes)和快速凸壳算法,提出一种结合改进快速凸壳算法的SVM用于故障诊断研究。该融合算法利用改进简化的Alpha Shapes算法提取点集的边界数据点,作为改进的快速凸壳算法的对象,减少凸壳算法递归的工作量。实验结果表明:该算法平均只提取了数据集0.26%的数据点,且计算的时间也相应降低。最后实验同样表明该算法的性能优于单一的SVM算法。

Study of concentration of amniotic fluid Alpha-fetal protein in thalassemia fetus

Objective:To test the hypothesis that concentration of amniotic fluid alpha-fetal protein(AFAFP) is increased in thalassemia fetus.Methods:A total of 135 cases of amniocentesis admitted from July 2013 to December 2014 were included in this study.Among them 98 cases of normal fetuses were assigned into control group and 37 cases of thalassemia fetus were included as thalassemia fetus group.Alpha-fetoprotein levels detected by enzyme linked immunosorbent assay and the alpha-fetoprotein concentration were compared between the two groups.There is no significant difference in gestrational age between the two groups.Results:1.AFP concentration in thalassemia fetus group was significantly higher than that of normal control group [(1541.65±734.78) μg/mL vs.(2728.84± 1539.97) μg/mL ],and amniotic fluid AFP concentration was related to fetal thalassemia.2.AFAFP concentration in pureα-thalassemia fetus was higher than that of β thalassemia fetus or mixed αand was not significant.Conclusions:Concentration of a β thalassemia fetus,but the difference mniotic fluid alpha-fetal protein is increased in thalassemia fetus.AFP concentration inα-thalassemia fetus was higher than that of β thalassemia or mixed αand lore β thalassemia fetus but difference was not significance.Further studies are needed to exp the possible correlation between Down syndrome and biochemical markers of Thalassemia.

Sickle-cell and alpha-thalassemia traits resulting in nonatherosclerotic myocardial infarction:Beyond coincidence?

Alpha-thalassemia trait and sickle trait are not commonly considered risk factors of ischemic heart disease.We report the case of a non-atherosclerotic silent myocardial infarction in a 46-year-old woman,carrier of the alphathalassemia trait(homozygous deletion of locus-3.7) combined with sickle cell trait.While the patient was included as healthy volunteer for a metabolic study,we performed cardiac magnetic resonance imagery showing a left ventricle apicolateral myocardial infarction.Coronary computed tomography angiography showed normal coronary arteries with a coronary calcium score of 0.The patient was treated with low-dose aspirin in secondary prevention afterwards.This case allows us to discuss cardiovascular risk among patients presenting with both alpha-thalassemia trait and sickle cell trait and the indication of cardiac imagery in such patients even when considered as low-cardiovascular risk.

模型与数据双驱动的失眠脑电alpha节律研究

失眠是一种典型的睡眠障碍,以入睡困难、睡眠深度或频度过短、早醒及睡眠时间不足等为主要特征。临床上一些失眠患者在快速眼动(REM)睡眠期会出现明显的脑电alpha节律活动增强现象,但发生这一现象的内在机制尚不清楚。基于此,从计算神经科学的角度出发,结合Liley神经计算模型与临床失眠脑电数据,探索失眠患者在REM期典型放电节律的发生机制。首先,设计一种基于马尔可夫蒙特卡洛的Liley模型关键参数的自动选择与估计方法;其次,结合失眠患者脑电数据,确定影响alpha节律发放的模型关键参数,并据此给出失眠患者REM期脑电alpha节律活动增强的机制假设:抑制性突触活动强度的降低会诱导alpha节律活动的增强。所获结果对于改善失眠患者的睡眠质量并控制病情发展具有一定的指导作用和临床价值。

Alpha稳定分布噪声下基于特征值之差频谱感知算法

针对基于特征值的谱感知算法在脉冲噪声的环境下感知性能不佳的问题,分析矩阵全部的特征值,引入矩阵特征值的几何均值,提出了基于分数低阶协方差矩阵的最大特征值与特征值几何均值之差(difference between maximum eigenvalue and geometric mean of eigenvalue,DMGM)的频谱感知算法。选择了Alpha稳定分布噪声模拟脉冲噪声环境,理论分析与仿真实验结果表明,在不增加算法复杂度的前提下,DMGM算法与其他算法相比,更适用于脉冲噪声环境,在低信噪比条件下具有更好的感知性能。

Thalassemia Screening by Sentiment Analysis on Social Media Platform Twitter

Thalassemia syndrome is a genetic blood disorder induced by the reduction of normal hemoglobin production,resulting in a drop in the size of red blood cells.In severe forms,it can lead to death.This genetic disorder has posed a major burden on public health wherein patients with severe thalassemia need periodic therapy of iron chelation and blood transfusion for survival.Therefore,controlling thalassemia is extremely important and is made by promoting screening to the general population,particularly among thalassemia carriers.Today Twitter is one of the most influential social media platforms for sharing opinions and discussing different topics like people’s health conditions and major public health affairs.Exploring individuals’sentiments in these tweets helps the research centers to formulate strategies to promote thalassemia screening to the public.An effective Lexiconbased approach has been introduced in this study by highlighting a classifier called valence aware dictionary for sentiment reasoning(VADER).In this study applied twitter intelligence tool(TWINT),Natural Language Toolkit(NLTK),and VADER constitute the three main tools.VADER represents a gold-standard sentiment lexicon,which is basically tailored to attitudes that are communicated by using social media.The contribution of this study is to introduce an effective Lexicon-based approach by highlighting a classifier calledVADERto analyze the sentiment of the general population,particularly among thalassemia carriers on the social media platform Twitter.In this study,the results showed that the proposed approach achieved 0.829,0.816,and 0.818 regarding precision,recall,together with F-score,respectively.The tweets were crawled using the search keywords,“thalassemia screening,”thalassemia test,“and thalassemia diagnosis”.Finally,results showed that India and Pakistan ranked the highest in mentions in tweets by the public’s conversations on thalassemia screening with 181 and 164 tweets,respectively.

Counting of alpha particle tracks on imaging plate based on a convolutional neural network

Imaging plates are widely used to detect alpha particles to track information,and the number of alpha particle tracks is affected by the overlapping and fading effects of the track information.In this study,an experiment and a simulation were used to calibrate the efficiency parameter of an imaging plate,which was used to calculate the grayscale.Images were created by using grayscale,which trained the convolutional neural network to count the alpha tracks.The results demonstrated that the trained convolutional neural network can evaluate the alpha track counts based on the source and background images with a wider linear range,which was unaffected by the overlapping effect.The alpha track counts were unaffected by the fading effect within 60 min,where the calibrated formula for the fading effect was analyzed for 132.7 min.The detection efficiency of the trained convolutional neural network for inhomogeneous ^(241)Am sources(2π emission)was 0.6050±0.0399,whereas the efficiency curve of the photo-stimulated luminescence method was lower than that of the trained convolutional neural network.

Joint Detection of Serum Vitamin D,Body Mass Index,and Tumor Necrosis Factor Alpha for the Diagnosis of Crohn’s Disease

Objective Vitamin D(VD)deficiency was reported to contribute to the progression of Crohn’s disease(CD)and affect the prognosis of CD patients.This study investigated the role of serum VD,body mass index(BMI),and tumor necrosis factor alpha(TNF-α)in the diagnosis of Crohn’s disease.Methods CD patients(n=76)and healthy subjects(n=76)were enrolled between May 2019 and December 2020.The serum 25-hydroxyvitamin D[25(OH)D]levels,BMI,and TNF-αlevels,together with other biochemical parameters,were assessed before treatment.The diagnostic efficacy of the single and joint detection of serum 25(OH)D,BMI,and TNF-αwas determined using receiver operating characteristic(ROC)curves.Results The levels of 25(OH)D,BMI,and nutritional indicators,including hemoglobin,total protein,albumin,and high-density lipoprotein cholesterol,were much lower,and the TNF-αlevels were much higher in the CD patients than in the healthy subjects(P<0.05 for all).The areas under the ROC curve for the single detection of 25(OH)D,BMI,and TNF-αwere 0.887,0.896,and 0.838,respectively,with the optimal cutoff values being 20.64 ng/mL,19.77 kg/m^(2),and 6.85 fmol/mL,respectively.The diagnostic efficacy of the joint detection of 25(OH)D,BMI,and TNF-αwas the highest,with an area under the ROC curve of 0.988(95%CI:0.968–1.000).Conclusion The joint detection of 25(OH)D,TNF-α,and BMI showed high sensitivity,specificity,and accuracy in CD diagnosis;thus,it would be effective for the diagnosis of CD in clinical practice.

F-box only protein 2 exacerbates non-alcoholic fatty liver disease by targeting the hydroxyl CoA dehydrogenase alpha subunit

BACKGROUND Non-alcoholic fatty liver disease(NAFLD)is a major health burden with an increasing global incidence.Unfortunately,the unavailability of knowledge underlying NAFLD pathogenesis inhibits effective preventive and therapeutic measures.AIM To explore the molecular mechanism of NAFLD.METHODS Whole genome sequencing(WGS)analysis was performed on liver tissues from patients with NAFLD(n=6)and patients with normal metabolic conditions(n=6)to identify the target genes.A NAFLD C57BL6/J mouse model induced by 16 wk of high-fat diet feeding and a hepatocyte-specific F-box only protein 2(FBXO2)overexpression mouse model were used for in vivo studies.Plasmid transfection,co-immunoprecipitation-based mass spectrometry assays,and ubiquitination in HepG2 cells and HEK293T cells were used for in vitro studies.RESULTS A total of 30982 genes were detected in WGS analysis,with 649 up-regulated and 178 down-regulated.Expression of FBXO2,an E3 ligase,was upregulated in the liver tissues of patients with NAFLD.Hepatocyte-specific FBXO2 overexpression facilitated NAFLD-associated phenotypes in mice.Overexpression of FBXO2 aggravated odium oleate(OA)-induced lipid accumulation in HepG2 cells,resulting in an abnormal expression of genes related to lipid metabolism,such as fatty acid synthase,peroxisome proliferator-activated receptor alpha,and so on.In contrast,knocking down FBXO2 in HepG2 cells significantly alleviated the OA-induced lipid accumulation and aberrant expression of lipid metabolism genes.The hydroxyl CoA dehydrogenase alpha subunit(HADHA),a protein involved in oxidative stress,was a target of FBXO2-mediated ubiquitination.FBXO2 directly bound to HADHA and facilitated its proteasomal degradation in HepG2 and HEK293T cells.Supplementation with HADHA alleviated lipid accumulation caused by FBXO2 overexpression in HepG2 cells.CONCLUSION FBXO2 exacerbates lipid accumulation by targeting HADHA and is a potential therapeutic target for NAFLD。

Measuring the Awareness of Thalassemia in Saudi Arabia

Introduction: Thalassemia disorder is a genetic disease that causes the blood to have less hemoglobin than normal, the main requirement to control thalassemia’s propagation is to educate the entire society. Methodology: A descriptive survey was taken to evaluate the awareness of thalassemia among Saudi Arabia’s society, with a sample size of 384. Results: The results were written in frequencies, and it shows that most of the participants were unaware and lacking information on thalassemia syndrome. Discussion: The results of this study provide valuable insights into the awareness of thalassemia in Saudi Arabia and highlight the need to raise awareness of this disease. Conclusion: This study is not comprehensive because the survey was not disrupted evenly, but it can give us an overview of the awareness of thalassemia in Saudi Arabia, and it shows that most of the participants were unaware and lacked information on thalassemia.

Ratio of hemoglobin to mean corpuscular volume: A new index for discriminating between iron deficiency anemia and thalassemia trait

BACKGROUND Iron deficiency anemia(IDA)and thalassemia trait(TT)are the most common microcytic and hypochromic anemias.Differentiation between mild TT and early IDA is still a clinical challenge.AIM To develop and validate a new index for discriminating between IDA and TT.METHODS Blood count data from 126 patients,consisting of 43 TT patients and 83 IDA pa-tients,was retrospectively analyzed to develop a new index formula.This formula was further validated in another 61 patients,consisting of 48 TT patients and 13 IDA patients.RESULTS The new index is the ratio of hemoglobin to mean corpuscular volume.Its sen-sitivity,specificity,accuracy,Youden’s Index,area under the receiver operating characteristic curve,and Kappa coefficient in discriminating between IDA and TT were 93.5%,78.4%,83.3%,0.72,0.97,and 0.65,respectively.CONCLUSION This new index has good diagnostic performance in discriminating between mild TT and early IDA.It requires only two results of complete blood count,which can be a very desirable feature in under-resourced scenarios.