The influence of twist angle on the electronic and phononic band of 2D twisted bilayer SiC.

Silicon carbide has a planar two-dimensional structure; therefore it is a potential material for constructing twisted bilayer systems for applications. In this study, DFT calculations were performed on four models with different twist angles. We chose angles of 21.8°, 17.9°, 13.2°, and 5.1° to estimate the dependence of the electronic and phononic properties on the twist angle. The results show that the band gap of bilayer SiC can be changed proportionally by changing the twist angle. However, there are only small variations in the band gaps, with an increment of 0.24 eV by changing the twist angle from 5.1° to 21.8°. At four considered twist angles, the band gaps decrease significantly when fixing the structure of each layer and pressing the separation distance down to 3.5 Å, 3.0 Å, 2.7 Å, and 2.5 Å. A noteworthy point is that the pressing also makes the band linearly smaller at a certain rate regardless of the twist angles. Meanwhile, the phonon bands are not affected by the value of the twist angle. The optical bands are between 900 cm-1 and 1100 cm-1 and the acoustic bands are between 0 cm-1 and 650 cm-1 at four twist angles.

Tracking Multiple Targets from Multistatic Doppler Radar with Unknown Probability of Detection.

The measurements from multistatic radar systems are typically subjected to complicated data association, noise corruption, missed detection, and false alarms. Moreover, most of the current multistatic Doppler radar-based approaches in multitarget tracking are based on the assumption of known detection probability. This assumption can lead to biased or even complete corruption of estimation results. This paper proposes a method for tracking multiple targets from multistatic Doppler radar with unknown detection probability. A closed form labeled multitarget Bayes filter was used to track unknown and time-varying targets with unknown probability of detection in the presence of clutter, misdetection, and association uncertainty. The efficiency of the proposed algorithm was illustrated via numerical simulation examples.

Molecular analysis of haemoglobin E in Southeast Asian populations.

Haemoglobin (Hb) E is the most common Hb variant in Asia where its gene frequency approaches 0.3 in some areas. We studied genetic background of Hb E genes among Southeast Asian populations. This study examined ß-globin gene haplotypes linked to haemoglobin E (Hb E) in diverse groups of Southeast Asian populations. The study was conducted on southern Thai (22 alleles), Cambodian (84 alleles), Laotian (120 alleles), Vietnamese (87 alleles) and Burmese (one allele) subjects. Results were compared with those of previous studies in northeast Thailand, the Yunnan of China, West India and Europe. Ten different haplotypes were observed. The four most common haplotypes were haplotypes 1 (- + - + + + -) and 2 (+ - - - - + -) on chromosomes with framework 2 and haplotypes 6 (- + - + + - +) and 7 (+ - - - - - +) on chromosomes with framework 3 variety. Phylogenetic analysis indicated that haplotype 1 is a relatively recent haplotype found in all populations, whereas haplotype 6 is found predominately in Cambodians. The results indicate that at least two genetic origins of Hb E are responsible for the high prevalence and spread of Hb E among Southeast Asian populations.

Thalassemia and hemoglobinopathies in Thua Thien Hue Province, Central Vietnam.

A community-based assessment of thalassemias and hemoglobinopathies was conducted at the Thua Thien Hue Province, Central Vietnam. By cluster sampling, a total of 410 pregnant women attending the antenatal care service at 30 commune health centers were recruited consecutively from September 2011 to June 2012. Hemoglobin (Hb) analysis was performed using an automated Hb analyzer. α-Thalassemia (α-thal) genes were identified by polymerase chain reaction (PCR)-based techniques. Out of the 410 pregnant women, 2.7% carried α(0)-thal and 1.2% were ß-thal carriers. One woman with the - -(THAI) deletion was also found. Among the females under survey, structural Hb variants with 3.2% Hb E [ß26(B8)Glu→Lys, GAG>AAG; HBB: c.78G>C] and 3.7% Hb Constant Spring [Hb CS; α142, Term→Gln, TAA>CAA (α2); HBA2: c.427T>C] were found. Assessing the frequency of thalassemias and hemoglobinopathies by ethnicity, Kinh (Vietnamese) and ethnic minority groups, Hb CS with a high frequency of 24.0% was observed in the ethnic minority groups. These results provide basic population-based information, are useful not only for implementing measures for prevention and control of thalassemias in the region but also for studying the importance of thalassemias and hemoglobinopathies in ethnic minorities within Southeast Asia.