Multicategory reclassification statistics for assessing improvements in diagnostic accuracy

In this paper, we extend the definitions of the net reclassification improvement (NRI) and the integrated discrimination improvement (IDI) in the context of multicategory classification. Both measures were proposed in Pencina and others (2008. Evaluating the added predictive ability of a new marker: from area under the receiver operating characteristic (ROC) curve to reclassification and beyond. Statistics in Medicine 27, 157–172) as numeric characterizations of accuracy improvement for binary diagnostic tests and were shown to have certain advantage over analyses based on ROC curves or other regression approaches. Estimation and inference procedures for the multiclass NRI and IDI are provided in this paper along with necessary asymptotic distributional results. Simulations are conducted to study the finite-sample properties of the proposed estimators. Two medical examples are considered to illustrate our methodology

High Body Mass Index Is Associated with an Increased Risk of the Onset and Severity of Ossification of Spinal Ligaments

BackgroundOssification of the posterior longitudinal ligament (OPLL) and that of ligamentum flavum (OLF) are the main types of the ossification of spinal ligaments (OSL) that cause the thoracic myelopathy. Although several studies have investigated the relationship of body mass index (BMI) with the onset or severity of OSL, it remains unverified due to the contradictory results of existing evidence. A systematic review and meta-analysis were performed in this work to determine the relationship of BMI with the onset and severity of OSL.MethodsPubMed, EMBASE, Web of Science, and Cochrane Library were comprehensively searched online for relevant studies focusing on the relationship of BMI with the onset or severity of the OSL. The difference in BMI of OSL (or severe OSL group) and non-OSL (or nonsevere OSL group) groups was evaluated using the mean difference (MD) with a corresponding 95% confidence interval (CI).ResultsFifteen studies were included in this systematic review and meta-analysis. The BMI of the OSL group was significantly higher than that of the non-OSL group (MD = 1.70 kg/m2, 95% CI = 1.02–2.39 kg/m2, and P < 0.01). Similar results were observed in the subgroup analysis of female (P < 0.01), OPLL (P < 0.01), and OLF (P < 0.01) populations. Three studies reported a significant association of BMI with the ossification index of OSL and the standardized regression coefficient ranging from 0.11 to 0.43 (P < 0.05). Moreover, a significantly higher BMI was observed in the severe OSL group compared with that in the nonsevere OSL group (MD = 3.09, 95% CI, 0.22–5.97 kg/m2, and P = 0.04).ConclusionThe significant association of high BMI with the onset and severity of OSL may provide new evidence and insights into the mechanism research and management of OSL

Skyrmion-Bubble Bundles in an X-type Sr2Co2Fe28O46 Hexaferrite above Room Temperature

Magnetic skyrmions are spin swirls that possess topological nontriviality and are considered particle-like entities. They are distinguished by an integer topological charge Q. The presence of skyrmion bundles provides an opportunity to explore the range of values for Q, which is crucial for the advancement of topological spintronic devices with multi-Q properties. In this study, we present a new material candidate, Sr2Co2Fe28O46 hexaferrite of the X-type, which hosts small dipolar skyrmions at room temperature and above. By exploiting reversed magnetic fields from metastable skyrmion bubbles at zero fields, we can incorporate skyrmion-bubble bundles with different interior skyrmion/bubble numbers, topological charges, and morphologies at room temperature. Our experimental findings are consistently supported by micromagnetic simulations. Our results highlight the versatility of topological spin textures in centrosymmetric uniaxial magnets, thereby paving the way for the development of room-temperature topological spintronic devices with multi-Q characteristics.Comment: https://doi.org/10.1002/adma.20230611

A single-step preparation of carbohydrate functionalized monoliths for separation and trapping of polar compounds

A single-step copolymerization strategy was developed for the preparation of carbohydrate (glucose and maltose) functionalized monoliths using click reaction. Firstly, novel carbohydrate-functionalized methacrylate monomers were synthesized through Cu(I)-catalyzed 1,3-dipolar cycloaddition (alkyne-azide reaction) of terminal alkyne with azide of carbohydrate derivatives. The corresponding carbohydrate functionalized monolithic columns were then prepared through a single-step in-situ copolymerization. The physicochemical properties and performance of the fabricated monolithic columns were evaluated using scanning electron microscopy, Fourier-transform infrared spectroscopy, and nano-liquid chromatography. For the optimized monolithic column, satisfactory column permeability and good separation performance were demonstrated for polar compounds including nucleoside, phenolic compounds and benzoic acid derivatives. The monolithic column is also highly useful for selective and efficient enrichment of glycopeptides from human IgG tryptic digests. This study not only provided a novel hydrophilic column for separation and selective trapping of polar compounds, but also proposed a facile and efficient approach for preparing carbohydrate functionalized monoliths

Clinical features of ST-segment elevation myocardial infarction in young Chinese patients

Background: To investigate the clinical characteristics, angiographic findings and clinical outcomes (in-hospital) of young adults with acute myocardium infarction in a Chinese population. Methods: This was an observational study. Five hundred and forty-nine patients who suffered with ST-segment elevation myocardial infarction (STEMI) firstly between January 2013 and December 2015 were enrolled consecutively. All patients were divided into two groups: “young group” patients were ≤ 50 years old; and “non-young group” patients were > 50 years old. Clinical features were compared, angiographic findings and clinical outcomes were observed between the two groups. Results: There were 131 and 418 patients included in the young group and the non-young group, respectively. Twenty-eight patients suffered deaths during the hospital stay and only one death occurred in the young group. Compared with non-young group, the young group was associated with male, smoke, fewer chronic diseases, Killip class I on admission, lower level of N-terminal pro B-type natriuretic peptide (NT-proBNP), higher level of triglyceride and lower level of high-density lipoprotein cholesterol (HDL-C), single-vessel lesion and intracoronary thrombus (p < 0.005). The average length of hospital stay of non-young group was 1.5 days longer than the young group. Compared with the non-young group, the young group inclined not to use or use only one stent (p = 0.026). Multivariable logistic regression analysis showed that older age, shorter hospital stay, advanced Killip class III/IV, increased white blood cell and NT-proBNP were independent risk factors for survival in acute STEMI patients during hospitalization (p < 0.005). Conclusions: Compared with non-young group, the young group was associated with male, smoke, higher level of triglyceride and lower level of HDL-C. The condition of patients in young group were relatively mild and the risk of death during hospitalization was lower than the other group

Observation of Hybrid Magnetic Skyrmion Bubbles in Fe3Sn2 Nanodisks

It is well known that there are two types of magnetic bubbles in uniaxial magnets. Here, using Lorentz-transimission electronic microscopy magnetic imaging, we report the direct experimental observation of 3D type-III hybrid bubbles, which comprise N\'eel-twisted skyrmion bubbles with topological charge Q = -1 in near-surface layers and type-II bubbles with Q = 0 in interior layers, in Fe3Sn2 nanodisks. Using the tilted magnetic field, we further show the controlled topological magnetic transformations of three types of bubbles in a confined ferromagnetic nanodisk. Our observations are well reproduced using micromagnetic simulations based on measured magnetic parameters. Our results advance fundamental classification and understanding of magnetic bubbles, which could propel the applications of three-dimensional magnetism.Comment: https://doi.org/10.1103/PhysRevB.107.17442