High Expression of PRNP Predicts Poor Prognosis in Korean Patients with Gastric Cancer

Gastric cancer (GC) has the highest occurrence and fourth-highest mortality rate of all cancers in Korea. Although survival rates are improving with the development of diagnosis and treatment methods, the five-year survival rate for stage 4 GC in Korea remains <10%. Therefore, it is important to identify candidate prognostic factors for predicting poor prognosis. PRNP is a gene encoding the prion protein PrP, which has been noted for its role in the nervous system and is known to be upregulated in various cancers and associated with both cell proliferation and metastasis. However, the value of PRNP as a prognostic factor for Korean GC patients remains unclear. Here, we analyzed the relationship between PRNP expression and survival in three independent datasets for Korean patients with GC as well as the TCGA-STAD dataset. Survival analysis indicates that high levels of PRNP expression are associated with poor overall survival of patients with GC. Gene set enrichment analysis showed that PRNP is associated with epithelial mesenchymal transition and Hedgehog signaling. In addition, proliferation of GC cell lines was inhibited after siRNA-mediated knockdown of PRNP. In conclusion, our study suggests a potential role for PRNP as a candidate prognostic factor for patients with GC.

Use of Information Criteria in the Study of Group Differences in Trace Lines

A brief review of various information criteria is presented for the detection of differential item functioning (DIF) under item response theory (IRT). An illustration of using information criteria for model selection as well as results with simulated data are presented and contrasted with the IRT likelihood ratio (LR) DIF detection method. Use of information criteria for general IRT model selection is discussed.

Rigorous formulation for electromagnetic plane-wave scattering from a general-shaped groove in a perfectly conducting plane

Scattering of an obliquely incident plane wave by a general-shaped groove engraved on a perfectly conducting plane is rigorously solved. The scattered field is represented by a Fourier-integral representation. To analytically represent the fields in a general-shaped groove, the groove is divided into L number of layers. Fields are then expressed in each layer as summations of 2D spatial harmonic fields with unknown coefficients. Matching the boundary conditions between layers provides a linear set of equations connecting all the unknown harmonic coefficients. Judicious use of Fourier transform on the equations resulting from matching boundary conditions at the groove aperture provides a series representation of the scattered field in the spectral domain with unknown harmonic coefficients of the first layer in the groove. A stable solution is obtained by solving the complete system of equations with an adaptive choice for the number of modes in each layer.

Acoustic scattering from two circular apertures in a thick hard plane

A problem of acoustic wave scattering from two circular apertures in a thick hard plane is solved. The Hankel transform and mode matching is used to represent the scattered field in rapidly convergent series. The reflection coefficient, transmission coefficient, and far-zone field are rigorously derived and presented in numerically efficient forms. Numerical computations are performed to illustrate scattering behaviors in terms of aperture geometry.

Acoustic hybrid junction in a rectangular waveguide

Acoustic scattering from a hybrid junction in a rectangular waveguide is studied. The Fourier transform and mode matching is used to represent the scattered wave and the simultaneous equations for the modal coefficients are formulated. A residue calculus is utilized to obtain a solution to the simultaneous equations in fast-converging series. Numerical computations are performed to show the behavior of transmission in terms of junction geometry and operating frequency. The utility of acoustic hybrid junction is discussed in terms of its decoupling characteristics.

Examination of the factorial validity of the Group Environment Questionnaire

The purpose of this study was to test the hypothesized factor structure of the Group Environment Questionnaire (GEQ) with confirmatory factor analysis and to ascertain the degree of factorial invariance across gender and across type of sport (team, individual). Additionally, the underlying theoretical structure on which the GEQ was developed was examined by fitting the data to alternative hierarchical factor structures. These models were tested with GEQ data collected on 740 high school varsity athletes (426 males, 314 females). It was shown that the males and females had different factor structures and that neither group exhibited the hypothesized structure. Attempts to fit the data to a two-factor and a second-order hierarchical factor model were unsuccessful. Finally, exploratory factor analysis did not produce a satisfactory four-factor solution. It was concluded that the data from this sample do not support the hypothesized four-factor structure of the GEQ and that further examination of the factor structure of this instrument is required.