A K+-sensitive AND-gate dual-mode probe for simultaneous tumor imaging and malignancy identificationOA

Although molecular imaging probes have the potential to non-invasively diagnose a tumor,imaging probes that can detect a tumor and simultaneously identify tumor malignancy remain elusive.Here,we demonstrate a potassium ion(K+) sensitive dual-mode nanoprobe(KDMN) for non-invasive tumor imaging and malignancy identification,which operates via a cascaded ’AND’ logic gate controlled by inputs of magnetic resonance imaging(MRI) and fluorescence imaging(FI) signals.We encapsulate commercial K⁺     

应用分数微积分求线性三阶常微分方程(包含均匀及非均匀)的特解(英文)

依分数微积分定义及Ｌｅｍｍａ 去解线性三阶常微分方程的特解,若用传统方法（ 级数解） 不但繁杂,有时无法求解,因此用分数微积分法求解非常简单快速．     

Life Experiences among Urban Adolescents: Examining the Role of Context

Interest in the influence of context on the psychosocial development of adolescents led to the examination of neighborhood effects on the experience of adolescent life stress. Because of concerns regarding the population and ecological validity of existing measures of adolescent life events, the research group developed a scale for the measurement of life events among urban adolescents based on data from focus group interviews in the community of interest. Investigators utilized three strategies to examine the impact of neighborhood on adolescents' perceptions of life stress in a sample of 114 adolescents (mean age = 15). Results indicated that life stress in the peer domain varied by the adolescent's neighborhood of residence. In addition, family/community stress was linearly related to neighborhood indices of economic resources.     

Cumulative and Differential Effects of Early Child Care and Middle Childhood Out-of-School Time on Adolescent Functioning

Effects associated with early child care and out-of-school time (OST) during middle childhood were examined in a large sample of U.S. adolescents (N = 958). Both higher quality early child care AND more epochs of organized activities (afterschool programs and extracurricular activities) during middle childhood were linked to higher academic achievement at age 15. Differential associations were found in the behavioral domain. Higher quality early child care was associated with fewer externalizing problems, whereas more hours of early child care was linked to greater impulsivity. More epochs of organized activities was associated with greater social confidence. Relations between early child care and adolescent outcomes were not mediated or moderated by OST arrangements in middle childhood, consistent with independent, additive relations of these nonfamilial settings.     

A New Statistic to Assess Fitness of Cubic-Spline Postsmoothing

In equating, smoothing techniques are frequently used to diminish sampling error. There are typically two types of smoothing: presmoothing and postsmoothing. For polynomial log-linear presmoothing, an optimum smoothing degree can be determined statistically based on the Akaike information criterion or Chi-square difference criterion. For cubic-spline postsmoothing, visual inspection has been an important tool in choosing such optimum degrees in operational settings. This study introduces a new statistic for assessing the fitness of the cubic-spline postsmoothing method, which accommodates three conditions: (1) one standard error band, (2) deviation from unsmoothed equivalents, and (3) smoothness. A principal advantage of the new statistic proposed in this study is that an optimum degree of smoothing can be selected automatically by giving consistent amount of attention to deviation and smoothness across multiple equatings, whereas visual inspection may not be consistent.     

IRT Approaches to Modeling Scores on Mixed-Format Tests

This article considers psychometric properties of composite raw scores and transformed scale scores on mixed-format tests that consist of a mixture of multiple-choice and free-response items. Test scores on several mixed-format tests are evaluated with respect to conditional and overall standard errors of measurement, score reliability, and classification consistency and accuracy under three item response theory (IRT) frameworks: unidimensional IRT (UIRT), simple structure multidimensional IRT (SS-MIRT), and bifactor multidimensional IRT (BF-MIRT) models. Illustrative examples are presented using data from three mixed-format exams with various levels of format effects. In general, the two MIRT models produced similar results, while the UIRT model resulted in consistently lower estimates of reliability and classification consistency/accuracy indices compared to the MIRT models.     

Experiences,activities, and personal characteristics as predictors of engagement in STEM-focused summer programs

Out-of-school-time programs for youth that are focused on STEM content are often seen as affording opportunities to increase youth engagement, interest, and knowledge in STEM domains, yet we know relatively little about how youth actually experience such programs. In this article, we explore how experiences and activities employed in the delivery of summer STEM programs are associated with youth engagement during programming, and whether youth characteristics moderate these relationships. Data were collected from 203 youth (ages 10–16) in nine summer programs using multiple methods including video, experience sampling, and surveys. Through the use of cross-classified, multi-level models, we found that youth reported higher engagement in program activities they perceived to be more challenging and relevant, and in activities, they perceived to have more affordances for learning or developing skills. Gender moderated these relationships such that the positive relationships observed among males were muted or nonexistent for girls. We further identify that program activities are differently associated with fostering challenge, relevance, and learning. Findings have implications for out-of-school STEM programming for youth.