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BiFeO3 is the only material with ferroelectric Curie temperature and Néel temperature higher than room temperature, making it one of the most well-studied multiferroic materials. Based on an ab initio evolutionary algorithm, we predicted a new cubic C-type antiferromagnetic structure (Fd3¯m-BiFeO3) at ambient pressure. It was found that Fd3¯m-BiFeO3 is the hardest BiFeO3 (Vickers hardness ∼ 9.12 GPa), about 78% harder than R3c-BiFeO3 (the well-known multiferroic material), which contributes to extending the life of BiFeO3 devices. In addition, Fd3¯m-BiFeO3 has the largest shear modulus (83.74 GPa) and the largest Young's modulus (214.72 GPa). Besides, we found an interesting phenomenon that among the common multiferroic materials (BiFeO3, BaTiO3, PbTiO3, SrRuO3, KNbO3, and BiMnO3), Pnma-BiMnO3 has the largest bulk modulus, and its bulk modulus is about 15% larger than that of Fd3¯m-BiFeO3. However, its Vickers hardness (4.47 GPa) is much smaller than that of Fd3¯m-BiFeO3. This is because the Vickers hardness is proportional to the shear modulus and the shear modulus of Fd3¯m-BiFeO3 is larger than that of Pnma-BiMnO3. This work provides a deeper and more comprehensive understanding of BiFeO3. [ABSTRACT FROM AUTHOR]

BiFeO3 is one of the most widely studied multiferroic materials, because of its large spontaneous polarization at room temperature, as well as ferroelasticity and antiferromagnetism. Using an ab initio evolutionary algorithm, we found two new dynamically stable BiFeO3 structures (P63 and P6322) at ambient pressure. Their energy is only 0.0662 and 0.0659 eV per atom higher than the famous R3c–BiFeO3, and they have large spontaneous polarization, i.e., 71.82 μC cm−2 and 86.06 μC cm−2, respectively. The spontaneous polarization is caused by the movement of the Bi3+ atom along the [001] direction and mainly comes from the 6s electron of Bi3+. Interestingly, there is no lone pair electron of Bi3+, which is different from R3c–BiFeO3. The new structures have the same magnetic configurations as R3c–BiFeO3 (G-type antiferromagnetism), but they are characterized by one-dimensional channels linked by a group of two via surface-sharing oxygen octahedra. Due to the similarity of the two structures, both of them have indirect bandgap structures, and the bandgaps are 2.62 eV and 2.60 eV, respectively. This work not only broadens the structural diversity of BiFeO3 but also has constructive significance for the study of spontaneous polarization of new structures of multiferroic materials. [ABSTRACT FROM AUTHOR]

An ideal catalyst should have a relative hydrogen adsorption Gibbs free energy (Δ G H ) close to zero [J. K. Nørskov, et al., J. Electrochem. Soc. , 2005, 152 , J23]. However, most of the known catalysts cannot reach this standard. Based on first-principles calculations, we studied the hydrogen evolution reaction (HER) catalytic performance of pristine and defect (including vacancy and heteroatom doping) structures in terms of its Δ G H . We found that the Δ G H values of Co-doped HfS 2 and P-doped HfSe 2 are extremely close to zero, even closer than that of Pt (111), indicating that they are excellent catalysts. Moreover, we found that the source of the HER catalytic performance of Co-doped HfS 2 is the reduction of electron accumulation of the active site S atom. Our work provides two potential ideal catalysts and provides guidance for the experimental group to search for suitable catalysts.

BiFeO 3 is the only material with ferroelectric Curie temperature and Néel temperature higher than room temperature, making it one of the most well-studied multiferroic materials. Based on an ab initio evolutionary algorithm, we predicted a new cubic C-type antiferromagnetic structure ( Fd 3̄ m -BiFeO 3 ) at ambient pressure. It was found that Fd 3̄ m -BiFeO 3 is the hardest BiFeO 3 (Vickers hardness ∼ 9.12 GPa), about 78% harder than R 3 c -BiFeO 3 (the well-known multiferroic material), which contributes to extending the life of BiFeO 3 devices. In addition, Fd 3̄ m -BiFeO 3 has the largest shear modulus (83.74 GPa) and the largest Young's modulus (214.72 GPa). Besides, we found an interesting phenomenon that among the common multiferroic materials (BiFeO 3 , BaTiO 3 , PbTiO 3 , SrRuO 3 , KNbO 3 , and BiMnO 3 ), Pnma -BiMnO 3 has the largest bulk modulus, and its bulk modulus is about 15% larger than that of Fd 3̄ m -BiFeO 3 . However, its Vickers hardness (4.47 GPa) is much smaller than that of Fd 3̄ m -BiFeO 3 . This is because the Vickers hardness is proportional to the shear modulus and the shear modulus of Fd 3̄ m -BiFeO 3 is larger than that of Pnma -BiMnO 3 . This work provides a deeper and more comprehensive understanding of BiFeO 3 .

BiFeO 3 is one of the most widely studied multiferroic materials, because of its large spontaneous polarization at room temperature, as well as ferroelasticity and antiferromagnetism. Using an ab initio evolutionary algorithm, we found two new dynamically stable BiFeO 3 structures ( P 6 3 and P 6 3 22) at ambient pressure. Their energy is only 0.0662 and 0.0659 eV per atom higher than the famous R 3 c -BiFeO 3 , and they have large spontaneous polarization, i.e. , 71.82 μC cm -2 and 86.06 μC cm -2 , respectively. The spontaneous polarization is caused by the movement of the Bi 3+ atom along the [001] direction and mainly comes from the 6s electron of Bi 3+ . Interestingly, there is no lone pair electron of Bi 3+ , which is different from R 3 c -BiFeO 3 . The new structures have the same magnetic configurations as R 3 c -BiFeO 3 (G-type antiferromagnetism), but they are characterized by one-dimensional channels linked by a group of two via surface-sharing oxygen octahedra. Due to the similarity of the two structures, both of them have indirect bandgap structures, and the bandgaps are 2.62 eV and 2.60 eV, respectively. This work not only broadens the structural diversity of BiFeO 3 but also has constructive significance for the study of spontaneous polarization of new structures of multiferroic materials.

Objective: To explore the correlation between special A/O genotype and the O phenotype., Methods: Group O samples with partially reduced or lack of isoagglutinins were collected to determinate the ABO genotype with a PCR-sequence specific primer (PCR-SSP) assay. Seven samples with A/O genotype were selected for further study. Serological tests including forward and reverse typing, H antigen determination and adsorption/elution were carried out with a tube method. Genomic DNA was genotyped by amplifying and sequencing of the coding regions of exons 1 to 7 of the ABO gene., Results: Seven samples were serotyped as group O by the forward typing test. However, reduced anti-A activity was found in 5 samples by the reverse typing test, reduced anti-A and anti-B activities were found in 1 sample, and no anti-A isoagglutinin activity was found with 1 sample. H antigen was determined in all samples by routine serologic method. Neither anti-A nor anti-B was eluted from red cells derived from all samples. Three samples were genotyped as Ael02/O02, whilst the remainders were Ael02/O13, Ael02/O65, Am04/O75, Ael06/O02, respectively., Conclusion: Special A/O genotype may not express the A antigen, leading to the generation of group O red cells. Reduced or missed anti-A activity is the typical serological feature of this special group of O phenotype, for which ABO*Ael02 and ABO*O02 are the major alleles. Group O individuals with isoagglutinin detection problem should be grouped by serological tests and genomic DNA analysis.

Objective: To explore the molecular basis for a novel B(A) phenotype., Methods: Genomic DNA was abstracted from peripheral blood sample from the proband. ABO genotyping were carried out with sequence specific primer PCR (PCR-SSP). Exons 6 and 7 of the ABO gene were amplified with PCR and sequenced., Results: Anti-A serum could not be adsorbed or eluted by the donor's red blood cells, and no irregular antibodies were found in the plasma. PCR-SSP showed that the ABO genotype of the donor was ABO *B/O. Sequencing results showed that one of the alleles was ABO *O02, while the other could not be defined but contained the following mutation points, 297A>G, 526C>G, 657C>T, 701C>T, 703G>A, 796C>A, 803G>C, and 930G>A. The data was accepted by the GenBank (the loading code was KM974887) and the Blood Group Antigen Mutation Database, and was confirmed to be a novel allele of B(A)., Conclusion: A novel allele ABO *B(A)07 with 701C>T has been identified, which may facilitate further study on blood antigen variants and typing of the blood groups.

Objective: To investigate the frequency of anti-Mur and Mur antigen among blood donors in Guangzhou to provide evidence for guiding clinical transfusion and prenatal screening., Methods: DG Gel Coombs cards were used to screen active anti-Mur at 37 degrees celsius; from 2725 blood donors. Multiplex ligation-dependent probe amplification (MLPA) was used to genotype Mur antigen from 91 blood donors, and human anti-Mur serum was used to verify the phenotypes deduced from the genotypes., Results: The frequency of anti-Mur and genotyped Mur antigen was 0.04% (1/2725) and 6.59% (6/91), respectively, and the phenotyping results were consistent with the genotyping results., Conclusion: The blood donors in Guangzhou show a low frequency of anti-Mur and a relatively high frequency of Mur antigen. Genotyping using MLPA allows Mur antigen genotyping when commercial anti-Mur is not available.

Objective: To report a rare case of hemolytic disease of the newborn (HDN) with kernicterus caused by anti-Di(a) diagnosed using high-throughput genotyping multiplex ligation-dependent probe amplification (MLPA)., Methods: Conventional serological methods were used to detect the antibodies related with HDN. The genotypes of more than 40 red blood cell antigens for the newborn and her parents were obtained using the high-throughput MLPA assay. The antibody titers were tested using a standard serological method., Results: The unknown antibody against the low-frequency antigens was predicted based on the primary serological tests. The genotyping results for more than 40 red blood cell antigens of the newborn and her parents showed incompatible antigens of MNS and Diego blood group system, indicating the existence of anti-N or anti-Di(a). Further serological tests confirmed anti-Di(a) existence in the plasma of the newborn and her mother. The titer of anti-Di(a) in the mother's plasma was 1:32., Conclusion: Severe HDN including kernicterus can result from anti-Di(a). High-throughput genotyping MLPA assay can help type some rare antigens in complicated cases. The reagent red cell panels including Di(a)-positive cells are necessary in routine antibody screening test in Chinese population.