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Melioidosis is a fatal infectious disease in the tropics and subtropics. Currently, bacterial culture is the gold standard for diagnosis of the disease, but its sensitivity is relatively low. In this study, we evaluated four ELISAs using sera collected from culture-confirmed cases of melioidosis (n = 63), cases with other bacterial infections (n = 62), and healthy donors (n = 60). Antigens used for ELISAs were the whole-cell (WC) antigens and recombinant proteins of hemolysis co-regulated protein 1 (Hcp1), chaperonin GroEL1, and alkyl hydroperoxide reductase subunit C (AhpC). Using the cutoff values for optical density at 490 nm defined at a specificity of > 95%, the sensitivity of the WC, Hcp1, GroEL1, and AhpC ELISAs was 93.7%, 87.3%, 61.9%, and 57.1%, respectively. The combined WC/Hcp1 ELISA showed the greatest sensitivity and specificity of 98.4% and 95.1%, respectively. Of 511 and 500 sera collected from clinically suspected febrile patients admitted to the General Hospital of Ha Tinh Province and the Hue Central Hospital, respectively, combined WC/Hcp1 ELISAs showed 52 (10.2%) and 41 (8.2%) patients positive for melioidosis, respectively. The assay detected 14 of 14 (100%) and 21 of 23 (91.3%) culture-confirmed cases of melioidosis at Ha Tinh and Hue, respectively. A follow-up study of 38 patients positive for melioidosis by combined WC/Hcp1 ELISAs but negative for Burkholderia pseudomallei by culture method or not assigned to examine for bacterial culture resulted in 2 (5.3%) culture-reconfirmed patients with melioidosis, 9 (23.7%) deaths, 17 (44.7%) unhealthy patients, and 10 (26.3%) healthy persons. Combined WC/Hcp1 ELISA was a reliable serological method to detect underdiagnosed cases of melioidosis. Further investigations are needed to estimate the true sensitivity and specificity of the assay and the true number of cases of melioidosis.

Despite the excellent power conversion efficiency of multiple-cation mixed halide perovskite solar cells (PSCs), the underlying mechanisms in its efficiency improvement remain unclear. To promote t...

Dimensional engineering of perovskite solar cells has attracted significant research attention recently because of the potential to improve both device performance and stability. Here, a novel 2D passivation scheme for 3D perovskite solar cells is demonstrated using a mixed cation composition of 2D perovskite based on two different isomers of butylammonium iodide. The dual-cation 2D perovskite outperforms its single cation 2D counterparts in surface passivation quality, resulting in devices with an impressive open-circuit voltage of 1.21 V for a perovskite composition with an optical bandgap of ≈1.6 eV, and a champion efficiency of 23.27%. Using a combination of surface elemental analysis and valence electron spectra decomposition, it is shown that an in situ interaction between the 2D perovskite precursor and the 3D active layer results in surface intermixing of 3D and 2D perovskite phases, providing an effective combination of defect passivation and enhanced charge transfer, despite the semi-insulating nature of the 2D perovskite phase. The demonstration of the synergistic interaction of multiple organic spacer cations in a 2D passivation layer offers new opportunities for further enhancement of device performance with mixed dimensional perovskite solar cells.

The incorporation of Cl anion and MA/Cs cations into FAPbI3 perovskite has been shown to dramatically improve solar cell performance. However, the microscopic properties of hybrid metal halide perovskite materials are not well understood yet, and it is still unclear how ion incorporation stabilizes the cubic FAPbI3 perovskite. In this work, we conduct a systematic study on the effect of the CsCl/MACl additives on the microstructure, crystal structure, and defects (nanotwins and stacking faults) of FA-based perovskite solar cells (PSCs). We find that the cubic α-phase in pure FAPbI3 is unstable with evidence of additional phases in the experimental electron diffraction analyses, namely the hexagonal δ-phase, the cubic supercell structure (with double the lattice constant of the α-phase) and a rhombohedral phase. The addition of CsCl/MACl effectively stabilizes the cubic FAPbI3 with a 2 × 2 × 2 supercell expansion and the Im 3 space group. X-ray diffraction and photoluminescence studies show that the addition of CsCl/MACl results in a change in both the lattice parameter and the optical bandgap, respectively. The lattice contraction is a result of the incorporation of Cs/MA cations and Cl anion in the FAPbI3 perovskites. Moreover, the addition of CsCl is shown to minimize the density of defects and improve the photoluminescence yield as well as the minority carrier lifetime of the perovskite films. All of these factors contribute to the improved device performance with a maximum efficiency of 21.98% measured for the 10 mol% CsCl perovskite layer.

The work was supported by the Australian Government through the Australian Renewable Energy Agency (ARENA) and the Australian Research Council (ARC). T.P.W. is the recipient of an Australian Research Council Future Fellowship (Project No. FT180100302) funded by the Australian Government.

Since the marine environmental conditions are extremely different from the other ones, marine actinomycetes might produce novel bioactive compounds. Therefore, actinomycete strains were screened from marine water and sediment samples collected from the coastal areas of Northern Vietnam. Ninety-nine actinomycete strains were obtained on starch-casein agar media by dilution technique, only seven strains, named HP112, HP12, HP411, HPN11, HP 11, HPT13 and HPX12, showed significant antibacterial activity against both gram-positive and gram-negative bacteria (Bacillus subtilis ATCC 6633, Staphylococcus epidemidis ATCC 12228, Escherichia coli ATCC 11105). Further studies were carried out with the most active HP411 strain against Candida albicans ATCC 10231. This strain could grow rapidly on starch casein agar and other media with high salt containing 7-10% NaCl at 28-30oC. Spore-chain of HP411 showed an elongated and circular shape with 10 to 30 spores/chain. Identification of the strain was carried out by employing the taxonomical studies including the 16S rRNA sequence. Based on phylogenetic and phenotypic evidence it is proposed that HP411 to be belongs to species Streptomyces variabilis. The potent of the crude extract of fermentation broth of HP411 that are effective against wide range of pathogens: both grampositive, gram-negative and fungi. Further studies revealed that the crude extract HP411 could obtain the anticancer activity for cancer cell lines: Hep-G2 (liver cancer cell line); RD (cardiac and skeletal muscle letters cell line); FL (membrane of the uterus cancer cell line). However, the actinomycetes from marine ecosystem will be useful for the discovery of new drugs in the future.

Hybrid nanoporous MCF, SBA-15 and MCM-41 materials were synthesized via hydrothermal treatment and functionalized with 3-aminopropyltriethoxysilane (APTES) via post-synthesis grafting and sequently activated by glutardialdehyde and then were used to immobilize D-amino acid oxidase (DAAO). The amino-functionalized materials were characterized by various techniques: XRD, IR and N2 adsorption-desorption (BET). From characterization results, it indicated that these materials still maintained their structure after functionalization. The data IR and TGA-DTA analysis demonstrated the incorpotation of amine functional groups on the surface of APTES-functionalized samples. The DAAO immobilized on functionalized materials exhibited higher catalytic activity and stability for conversion of cephalosporin C (CPC) compare to those of non-functionalized one. Further more, the catalytic activity as well as stability of enzyme decreased in order MCF > SBA-15 > MCM-41 with the decrease of their pore size.