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Hedrick Watkins posted an update 6 months, 1 week ago
In item response theory, uncertainty associated with estimated item parameters can lead to greater uncertainty in subsequent analyses, such as estimating trait scores for individual examinees. Most existing methods to characterize or correct for item parameter uncertainty implicitly assume that the latent trait continuum is fixed across the posterior distribution of item parameters. However, the latent trait continuum can also be understood as an artifact of the fitted model, such that the location of this continuum is determined with error. In other words, item parameter estimation error implies uncertainty about the location of the metric. This article uses Ramsay’s (1996) geometry of the latent trait metric to develop a quantitative measure of metric stability, that is, the sampling variability of the latent trait continuum implied by errors in item parameter estimation. Through a series of illustrations, it is clarified how metric stability is related to other item response model evaluation outcomes (e.g., test information, model fit), and how metric stability can be useful in identifying well-determined regions of the latent trait continuum, making sample size recommendations, and selecting a model. Overall, the proposed measure of metric stability provides meaningful and highly interpretable information to aid in item response model evaluation.
Hypomethylating agents (HMA) remain the mainstay of treatment for patients with higher-risk myelodysplastic syndromes (HR-MDS). However, complete responses to HMAs are seen in <20% of cases and are typically not durable. For most patients, HMA failure is an eventual certainty that is associated with an abysmal prognosis.
PubMed and abstracts from annual meetings were searched in May 2020 to review recent studies on novel HMAs (e.g. ASTX727, CC-486, guadecitabine), molecularly targeted agents (e.g. mutant IDH1/2 inhibitors, BCL-2 inhibitors, APR246), and immune therapies (e.g. MBG453, anti-CD47) for the treatment of HR-MDS patients with HMA failure. Several molecules targeting cell signaling (e.g. rigosertib) are also in development. This manuscript also provides an overview of the state of genetic testing and its implications for an increasingly individualized treatment approach for patients with MDS.
Advances in the understanding of the genetic and immune pathogenesis of HMA failure will lead to biomarker-driven therapeutic approaches and to an era of individualized therapeutic concepts (e.g. IDH inhibitors and APR246). The improved understanding of molecular mechanisms of pathogenesis and immune evasion are offering further opportunities for the rational design of novel agents. Efforts to optimize frontline HMA-based treatment are of paramount importance.
Advances in the understanding of the genetic and immune pathogenesis of HMA failure will lead to biomarker-driven therapeutic approaches and to an era of individualized therapeutic concepts (e.g. IDH inhibitors and APR246). The improved understanding of molecular mechanisms of pathogenesis and immune evasion are offering further opportunities for the rational design of novel agents. Efforts to optimize frontline HMA-based treatment are of paramount importance.Background Imaging surveillance is important for the early diagnosis of recurrence following definitive treatment for oral squamous cell carcinoma (OSCC). The Neck Imaging Reporting and Data System (NI-RADS) provides a standardized template for surveillance imaging and categorizes probability of recurrence at the primary site and the neck (cervical lymph nodes) by assigning categories of 1 (no evidence of recurrence), 2 (low suspicion, subdivided into 2a and 2b for the primary site), 3 (high suspicion), or 4 (definite recurrence). Objectives The aim of this study was to determine the rate of locoregional and nodal OSCC recurrence stratified by NI-RADS category in patients undergoing surveillance CT or MRI. Methods This retrospective study included 158 patients enrolled in an institutional surveillance program after resection of OSCC with curative intent. N6-methyladenosine purchase A total of 503 contrast-enhanced CT or MRI examinations performed during surveillance were evaluated. Each examination was randomly assigned to one of four r recurrence, both for the primary site and the neck. Clinical Impact Radiologists and maxillofacial surgeons should implement NI-RADS in surveillance regimens for post-operative OSCC to help detect recurrences in an effective and standardized fashion by imaging.Food safety has become a major global concern and the rapid detection of food nutritional ingredients and contaminants has aroused much more attention. Nanomaterials-based fluorescent sensing holds great potential in designing highly sensitive and selective detection strategies for food safety analysis. Carbon dots (CDs) possess tremendous prospects in fluorescent sensing food ingredients and contaminants due to their superior properties of chemical and photostability, highly fluorescence with tunability, and no/low-toxicity. Numerous endeavors are demanded to contribute to overcoming the challenge of lower sensitivity and selectivity of the sensors interfered by various components in intricate food matrices to ensure food safety and human health. Nanohybrid CDs based ratiometric fluorescent sensing with self-calibration is regarded as an efficient strategy for the CDs based sensors for the specific recognition of target analyte in the food matrices. This work is devoted to reviewing the development of nanohybrid CDs based ratiometric fluorescent sensing platform and the perspectives of the platform for food safety. The applications of nanohybrid CDs in sensing are summarized and the sensing mechanisms are briefly discussed.This work applied environmental isotope techniques to validate the results of previous studies on recharge sources in a rural area in central Chile (34.3° S and 71.3° W) and discern the origin of nitrate contamination in wells. Stream water and groundwater samples were taken during three surveys, two during spring snowmelt and one in low-water conditions. Chemical analyses included major cations and anions, isotope analyses included 18O-H2O; 2H-H20; 3H-H20; 18O-NO3- and 15N-NO3-. The stable isotope data show that surface water and deep groundwater present depleted isotope values associated with recharge from the Andes Mountains and that shallow groundwater has more enriched isotope values that reflect the contribution of local recharge from rainwater infiltration. Depleted isotope values observed in shallow groundwater show the effect of recirculated river water used for irrigation. These results are consistent with the conceptual groundwater model developed in previous studies. Some wells have nitrate concentrations above the allowable limit for drinking water.
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