Results Of Linear Array Research Articles

A PSO-CVX Algorithm of Sum and Difference Beam Patterns for Time-Modulated Antenna Array

An integrated optimization of sum and difference beam for time-modulated linear antenna array is studied in this paper. The goal of sum and difference beam synthesis is to generate sum beam in the main band and difference beams in the first-order sideband with low side-lobe level through timing switches. The turn-on times of antenna array are achieved by solving a quadratic constraint linear programming; meanwhile, the opening times are optimized by particle swarm optimization algorithm. The results of linear array show that the sum and difference beam can be scanned within ± 40 degrees, with lower peak side-lobe level.

A comparison of the Linear Array and the Automated INNO-LiPA HPV Genotyping Systems on Pathological Specimens

The causative role of HPV infection in a wide range of diseases is well established, highlighting the importance of accurate HPV genotyping techniques applicable to various tissue types and conservation methods. This study compared the performance of the automated INNO-LiPA HPV Genotyping Extra II and the manual Linear Array HPV genotyping assays in diagnostically relevant specimens. Samples with discrepant results were also tested with Anyplex II HPV28 detection assay. DNA from 120 samples, primarily from anogenital and head-neck FFPE tissues and cervical cytology specimens, were analysed. Interclass correlation efficiencies between the assays and percentage and kappa agreements for individual genotypes were calculated. Overall, a high agreement was found between the two genotyping methods (>0.95), however, INNO-LiPA was more likely to identify genotypes in samples indicating low viral load and/or originating from FFPE tissues. Specifically, INNO-LiPA detected more genotypes in FFPE material harbouring multiple HPV infections; in particular HPV51 and 52 were the most affected high-risk genotypes. In contrast, Linear Array identified more low-risk HPV54 infections in both cytology and FFPE specimens. The discrepant genotypes detected by Anyplex resembled more the results of Linear Array than that of INNO-LiPA. We conclude that the assays are highly comparable, but differences may arise in a context dependent manner.

Assessment of the Roche Linear Array HPV Genotyping Test within the VALGENT framework

BackgroundCervical cancer screening programs are switching from cytology-based screening to high-risk (hr) HPV testing. Only clinically validated tests should be used in clinical practice. ObjectivesTo assess the clinical performance of the Roche Linear Array HPV genotyping test (Linear Array) within the VALGENT-3 framework. Study designThe VALGENT framework is designed for comprehensive comparison and clinical validation of HPV tests that have limited to extended genotyping capacity. The Linear Array enables type-specific detection of 37 HPV types. For the purpose of this study, Linear Array results were designated as positive only if one of the 13 hrHPV types also included in the Hybrid Capture 2 (HC2) was detected. The VALGENT-3 framework comprised 1600 samples obtained from Slovenian women (1300 sequential cases from routine cervical cancer screening enriched with 300 cytological abnormal samples). Sensitivity for cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) (n=127) and specificity for <CIN2 (n=1216) were assessed for Linear Array and for HC2 and non-inferiority of Linear Array relative to HC2 was checked. In addition, the prevalence of separate hrHPV types in the screening population, as well as the concordance for presence of HPV16, HPV18 and other hrHPV types between Linear Array and the Abbott RealTime High Risk HPV test (RealTime) were assessed. ResultsThe clinical sensitivity and specificity for CIN2+ of the Linear Array in the total study population was 97.6% (95% CI, 93.3–99.5%) and 91.7% (95% CI, 90.0–93.2%), respectively. The relative sensitivity and specificity of Linear Array vs HC2 was 1.02 [95% CI, 0.98–1.05, (p<0.001)] and 1.02 [95% CI, 1.01–1.03, (p<0.001)], respectively The overall prevalence of hrHPV using the Linear Array in the screening population was 10.5% (95% CI, 8.9–12.3%) with HPV16 and HPV18 detected in 2.3% and 0.9% of the samples, respectively. Excellent agreement for presence or absence of HPV16, HPV18 and other hrHPV between Linear Array and RealTime was observed. ConclusionsLinear Array showed similar sensitivity with higher specificity to detect CIN2+ compared to HC2. Detection of 13 hrHPV types with Linear Array fulfils the clinical accuracy requirements for primary cervical cancer screening.

Relative RF coil performance in carotid imaging

Computer simulations and measurements on human volunteers were used to test the extent to which the quality of carotid imaging might be improved by coil arrays that are not limited by a constraint on the number of RF coil receiver ports. Analytic near-field equations for the magnetic and electric fields of a rectangular loop resonator were used to estimate the relative signal-to-noise ratio (rSNR) along the length of a simulated carotid artery as a function of loop size, loop position and vessel depth. The sizes, positions and number of elements in a linear coil array that resulted in the maximum composite SNR along the length of a simulated carotid artery were then estimated. The linear array results were used to predict the total number of elements needed for optimal imaging of the carotid arteries. Also, three normal volunteers were imaged with a variety of RF coils, and the rSNR measurements along the lengths of the carotid artery were evaluated for each coil combination. The analytic simulation and the human volunteer measurements both show that improved SNR (e.g., >300% at the bifurcation) can be obtained with coils tailored to each specific region of the carotid artery in comparison to that obtained with four-element arrays designed and used to image the entire carotid artery. The resulting number of coil ports, 16 to 24, required for full coverage of the carotid arteries is consistent with the number of channels just becoming available on recently developed clinical scanners.