Spatial Distribution of Elemental Concentrations in Street Dust of Hanoi, Vietnam.

Street dust samples were collected at 163 locations across four different zones of Hanoi, Vietnam, covering different traffic and population densities. Samples were sieved into three fractions of different particle sizes and analyzed for elemental concentrations (K, Ca, Mn, Fe, Zn, Pb) using an X-ray fluorescence (XRF) instrument. The metal concentrations in street dust were compared among different sampling zones and with samples from background to evaluate the degree of pollution. The smallest size particle fraction (diameter <75 µm) contained higher concentrations of metals than the coarser ones (diameters = 75-180 and >180 µm). While concentrations of metals like Ca and Fe are spatially similar, concentrations of Pb and Zn in street dust varied between different zones, with the highest concentrations observed in dust from the downtown area, and lowest levels in the new suburb areas. Overall, compared to studies from cities in other countries, the mean concentration of Pb in street dust in Hanoi was relatively low, suggesting a lower risk to human health due to inhalation or ingestion of Pb-containing dust particles than in cities where Pb concentrations were several times higher.

Antioxidant and Antimicrobial Properties of Fruiting Body and Submerged Mycelium of Medicinal Mushroom Phellinus robiniae (Agaricomycetes).

This study was conducted to evaluate extraction yield, antioxidant content, antioxidant capacity and antibacterial activity of extracts obtained from submerged mycelium (ME) and fruiting body (FBE) of Phellinus robiniae NTH-PR1. The results showed that yields of ME and FBE reached 14.84 ± 0.63 and 18.89 ± 0.86%, respectively. TPSC, TPC, and TFC were present in both mycelium and fruiting body, and the more contents of them were found in fruiting body. The concentrations of TPSC, TPC and TFC in ME and FBE were 17.61 ± 0.67 and 21.56 ± 0.89 mg GE g-1, 9.31 ± 0.45 and 12.14 ± 0.56 mg QAE g-1, and 8.91 ± 0.53 and 9.04 ± 0.74 mg QE g-1, respectively. EC50 values for DPPH radical scavenging revealed FBE (260.62 ± 3.33 µg mL-1) was more effective than ME (298.21 ± 3.61 µg mL-1). EC50 values for ferrous ion chelating in ME and FBE were 411.87 ± 7.27 and 432.39 ± 2.23 µg mL-1, respectively. Thus, both extracts were able to inhibit Gram-positive and Gram-negative pathogenic bacterial strains, at concentrations ranging in 25-100 mg mL-1 of ME and 18.75-75 mg mL-1 of FBE for Gram-positive bacteria; ranging in 75-100 mg mL-1 of ME and 50-75 of FBE for Gram-negative bacteria. Overall submerged mycelial biomass and fruiting bodies of Ph. robiniae NTH-PR1 can be considered as useful natural sources for development of functional food, pharmaceuticals and cosmetic products or cosmeceuticals.

Structural, Optical and Magnetic Properties of (1-x)Bi0.5Na0.5TiO3+xBaCoO3-δ Solid Solution Systems Prepared by the Sol-Gel Method.

A new solid solution, (1-x)Bi0.5Na0.5TiO3+xBaCoO3-δ materials, was fabricated using the sol-gel method. X-ray diffraction showed that the crystal structure of the compound exhibited rhombohedral symmetry and is similar to the crystal structures of host Bi0.5Na0.5TiO3 materials. Distortions in the structures and reduction in the optical band gaps of the Bi0.5Na0.5TiO3 materials were possibly due to the random incorporation of Ba and Co cations into host lattice materials. The magnetic properties of the Bi0.5Na0.5TiO3 materials were tuned by controlling the concentrations of BaCoO3-δ as the solid solution. We expect that our work will provide valuable information on current methods for integrating ferromagnetic properties into lead-free ferroelectric materials for the development of multiferroic materials.

Experimental and theoretical studies on induced ferromagnetism of new (1 - x)Na0.5Bi0.5TiO3 + xBaFeO3-δ solid solution.

New solid solution of Na0.5Bi0.5TiO3 with BaFeO3-δ materials were fabricated by sol-gel method. Analysis of X-ray diffraction patterns indicated that BaFeO3-δ materials existed as a well solid solution and resulted in distortion the structure of host Na0.5Bi0.5TiO3 materials. The randomly incorporated Fe and Ba cations in the host Na0.5Bi0.5TiO3 crystal decreased the optical band gap from 3.11 to 2.48 eV, and induced the room-temperature ferromagnetism. Our density-functional theory calculations further suggested that both Ba for Bi/Na-site and Fe dopant, regardless of the substitutional sites, in Na0.5Bi0.5TiO3 lead to the induced magnetism, which is illustrated in terms of the exchange splitting between spin subbands through the crystal field theory and Jahn-Teller distortion effects. Our work proposes a simple method for fabricating lead-free ferroelectric materials with ferromagnetism property for multifunctional applications in smart electronic devices.

Pregnane glycosides from the leaves of Dregea volubilis and their α-glucosidase and α-amylase inhibitory activities.

Three new pregnane glycosides, drevoluosides O-Q (1-3) along with five known volubiloside C (4), dreageoside A11 (5), 17ß-marsdenin (6), stavaroside H (7), and hoyacarnoside G (8) were isolated from the methanol extract of the Dregea volubilis leaves. Their structures were elucidated by chemical and spectroscopic methods. Compounds 6-8 showed significant anti α-glucosidase activity with the inhibitory percentages ranging from 32.6 to 47.1% at the concentration of 200 µM. Compound 3 showed significant inhibitory α-amylase activity with IC50 value of 51.3 ± 2.1 µM.

Late Pleistocene-Holocene sedimentary evolution in the coastal zone of the Red River Delta.

The Red River Delta is considered one of the largest megadelta systems in Asia. The formation of this delta has been controlled by the continent-ocean interaction and sea-level fluctuation during the Cenozoic. In this study, we present a new sequence stratigraphic framework of the Red River Delta based on borehole lithofacies analysis and high resolution seismic data. The Late Pleistocene-Holocene sediments in the coastal zone of the Red River Delta were subdivided into three systems tracts: (1) the lowstand systems tract (LST) is characterized by a Late Pleistocene alluvial silty sand facies complex (arLSTQ1 3b); (2) the transgressive systems tract (TST) is illustrated by the coastal marsh facies complex and the lagoonal greenish-gray clay facies of Early-Middle Holocene (amt, mtTSTQ2 1-2); and (3) the highstand systems tract (HST) is composed of the Middle-Late Holocene deltaic clayish silt facies complex (amhHSTQ2 2-3). The boundaries between these three systems tracts are not isochronous, namely: (1) The LST-HST boundary has been associated with the Würm 2 Glaciation, which occurred at ~40-18 Ka.; (2) The TST-LST boundary is identified by a transgressive erosion surface, whose age ranges from ~12-5 Ka.; and (3) the HST-TST boundary is an unconformity between the submarine deltaic facies complex and the Middle Holocene marine flooding plain.

Author Correction: Structure, optical and magnetic properties of new Bi0.5Na0.5TiO3- SrMnO3-δ solid solution materials.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Structure, optical and magnetic properties of new Bi0.5Na0.5TiO3- SrMnO3-δ solid solution materials.

The new Bi0.5Na0.5TiO3-SrMnO3-δ solid solution materials were fabricated via sol-gel method. The random incorporation of Sr and Mn cations into host lattice of Bi0.5Na0.5TiO3 resulted in structural distortion and influenced on the reduction of the optical band gap from 3.07 eV to 1.81 eV for pure Bi0.5Na0.5TiO3 and 9 mol% SrMnO3-δ solid solution into Bi0.5Na0.5TiO3. The magnetic properties of Bi0.5Na0.5TiO3 materials at room temperature were tuned via compensation of diamagnetic material with weak-ferromagnetism to ferromagnetism with low SrMnO3-δ content and combination of paramagnetism/antiferromagnetism-like and ferromagnetism with higher SrMnO3-δ content solid solution in Bi0.5Na0.5TiO3. The tunable magnetic and optical properties of lead-free ferroelectric materials was promising for their application to green electronic devices.

Liver involvement associated with dengue infection in adults in Vietnam.

Globally, the number of adults hospitalized with dengue has increased markedly in recent years. It has been suggested that hepatic dysfunction is more significant in this group than among children. We describe the spectrum and evolution of disease manifestations among 644 adults with dengue who were prospectively recruited on admission to a major infectious disease hospital in southern Vietnam and compare them with a group of patients with similar illnesses not caused by dengue. Transaminase levels increased in virtually all dengue patients and correlated with other markers of disease severity. However, peak enzyme values usually occurred later than other complications. Clinically severe liver involvement was infrequent and idiosyncratic, but usually resulted in severe bleeding. Chronic co-infection with hepatitis B was associated with modestly but significantly increased levels of alanine aminotransferase, but did not otherwise impact the clinical picture.