Characterization of arsenic-resistant endophytic Priestia megaterium R2.5.2 isolated from ferns in an arsenic-contaminated multi-metal mine in Vietnam

Bioremediation is a biological process to remove or neutralize environmental pollutants. This study was carried out to investing at the efficacy of arsenic resistant endophytic bacteria isolated from Pteris vittata, Pityrogramma calomelanos, Blenchum orientale, and Nephrolepis exaltata, which grow in a highly arsenic (As) contamination mining site in Vietnam. Their segmented roots, stems, and leaves were homogenized separately and inoculated on LB agar plates containing 5mM As(III) and As(V). A total of 31 arsenic resistant endophytic strains were selected, in which strain R2.5.2 isolated from the root of P. calomelanos had the highest arsenic resistant capability. Strain R2.5.2 tolerated up to 320 mM and 160 mM of arsenate and arsenite, respectively. The strain developed well on a media of 0.1 5% NaCl, at 20-40ºC and pH 5 9, and actively utilized most of the sugar sources. It had a high IAA biosynthesis capacity with an average concentration of 19.14 mg/L, tolerated to 0.5-16 mM concentration of Ag+, Hg2+, Co2+, Ni2+, Cu2+, Cr4+, and reduced As(V). Based on 16s rDNA, R2.5.2 was identified as Priestia megaterium. The ars C gene coding for arsenate reductase catalyzing reduction of As(V) was successfully amplified in P. megaterium R2.5.2.  The selected strain may have potential use for bioremediation practice

PRELIMINARY STUDY ON CHEMICAL MECHANISM OF DECREASE OF TETRODOTOXIN CONTENT IN OVARIES OF A PUFFER FISH Lagocephalus inermis (Temminck and Schlegel, 1850) FERMENTED WITH RICE BRAN

Tetrodotoxins in salted and fermented ovaries with rice bran of a puffer fish Lagocephalus inermis (Temminck Schlegel, 1850) during five months were determined by high-performance liquid chromatography with fluorometric detector (HPLC- FLD). The analysed results showed that the original ovaries contained only tetrodotoxin with content of 7.59 µg/g fresh weight. 4,9-Anhydrotetrodotoxin - an isomer which is less toxic than tetrodotoxin has been found in all ovary samples since the second month. Tetrodotoxin in the ovaries disappeared in the 4th month of the experiment. In addition, 4,9-anhydrotetrodotoxin level in ovaries increased during fermentation. The present study contributes to clarifying the chemical mechanism of decreasing tetrodotoxin content in fermented ovary of puffer fish.Tetrodotoxins in salted and fermented ovaries with rice bran of a puffer fish Lagocephalus inermis (Temminck and Schlegel, 1850) during five months were determined by high-performance liquid chromatography with fluorometric detector (HPLC- FLD). The analysed results showed that the original ovaries contained only Tetrodotoxin with content of 7.59 µg/g fresh weight. 4,9-Anhydrotetrodotoxin- an isomer which is less toxic than Tetrodotoxin has been found in all ovary samples since the second month. Tetrodotoxin in the ovaries disappeared in the 4th month of the experiment. In addition, 4,9-Anhydrotetrodotoxin level in ovaries increased during fermentation. The present study contributes to clarify the chemical mechanism of decreasing Tetrodotoxin content in fermented ovary of puffer fish

MỘT SỐ ĐẶC TÍNH CỦA CANXI HYDROXYAPATIT CHIẾT XUẤT TỪ XƯƠNG CÁ NGỪ VẰN Katsuwonus pelamis

This paper is concerned with certain properties of calcium hydroxyapatite from skipjack tuna bone (Katsuwonus pelamis) which are by-products of fish export industry. Hydroxyapatite Ca10(PO4)6(OH)2 and β-tricalcium phosphate Ca3(PO4)2, the high-value compounds, have been successfully extracted from skipjack tuna bones. The bones were heated at different temperatures of 600oC, 900oC, 1200oC. While at 600oC hydroxyapatites were obtained with Ca/P ratio of 1.658, comparable to the value of 1.67 found in human bone; the hydroxyapatite crystals of average size of 0.25 µm were formed with the same size distribution. In case of heated bone samples at 900°C and 1200°C, the calcium formed were biphasic calcium phosphate composed of hydroxyapatite and β-tricalcium phosphate; the Ca/P ratio was between 1.660–1.665; the calcium crystals of more than 1 µm were highly porous and connected to each other in priority orientation of tube direction.Bài báo này trình bày kết quả nghiên cứu về một số đặc tính của canxi hydroxyapatit chiết xuất từ xương cá ngừ Katsuwonus pelamis, một sản phẩm phụ từ ngành xuất khẩu thịt cá ngừ. Các hợp chất có giá trị là hydroxyapatit Ca10(PO4)6(OH)2 và β-tricanxi phosphat β-TCP Ca3(PO4)2 đã được chiết xuất thành công từ xương cá ngừ vằn. Xương cá ngừ được nung ở các nhiệt độ khác nhau 600, 900 và 1.200oC. Dạng canxi thu được khi nung mẫu ở 600oC là hydroxyapatit với tỉ lệ Ca/P 1,658 gần với tỉ lệ Ca/P 1,67 trong xương người; các tinh thể hydroxyapatit có kích thước trung bình 0,25 µm và sự phân bố kích thước tương đối đồng đều. Đối với mẫu xương được xử lý ở 900 và 1.200oC, canxi thu được là hỗn hợp hai pha hydroxyapatit Ca10(PO4)6(OH)2 và β-tricanxi phosphat Ca3(PO4)2; tỉ lệ Ca/P từ 1,660–1,665, các tinh thể canxi có độ xốp cao và liên kết với nhau theo hướng ưu tiên kiểu hình ống với kích thước lớn hơn 1 µm

NICKEL-BASED MULTIWALLED CARBON NANOTUBE COMPOSITE COATINGS

Carbon nanotubes (CNTs) have been widely known as nanomaterials with excellent mechanical properties. Previous studies reported that the tensile strength of multi-walled carbon nanotubes (MWCNTs) was up to 63 GPa and single-walled carbon nanotubes (SWCNTs) could reach 150 GPa while the highest tensile strength of the steel was found to be about 1.8 GPa. SWCNTs could have Young’s modulus up to 1000 GPa that was much greater than the value of 209 GPa of steel. Therefore, there is a great potential to utilize CNTs as reinforced materials for composites in general and Ni electrodeposition coating in particular to improve hardness, durability, corrosion, and other physical and mechanical properties. This paper presents results of preparing and examining characteristics of the Nickel electrodeposition coatings containing MWCNTs (Ni-MWCNTs). The Ni-MWCNTs composite coatings deposited on a steel plate with the area of 0.4 dm2 using bipolar pulses at 470 Hz and 50oC in a 5-liter bath. Amount of CNTs varying from 1 g/l to 3 g/l was dispersed into the solution by using surfactants and ultrasonic vibration. CNTs used in the study was MWCNTs diameters in the range from 20 to 90 nanometers and few micrometers in length. The SEM, EDS, hardness and adhesion tests were conducted to analyze the properties of the electrodeposition coatings. The obtained results indicated that the hardness and adhesion of the Ni-CNTs coating were 1.5 and 1.46 times, respectively, higher than those of the Ni coating. In addition, adhesion of the Ni-CNTs coating was significantly improved

Simulation for Optimizing the Design of Cryogenic Stopping Cell for the IGISOL Facility at ELI-NP

The production of the exotic neutron-rich ion beams from photofission of the actinide targets in an IGISOL facility will be studied via an experimental program that will take place at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility. Geant4 simulation toolkit was used for optimizing the target configuration in order to maximize the rate of released photofission fragments from targets placed in a cell filled with He gas

A Wearable, Bending-Insensitive Respiration Sensor Using Highly Oriented Carbon Nanotube Film

Recently, wearable electronics for health monitoring have been demonstrated with considerable benefits for early-stage disease detection. This article reports a flexible, bending-insensitive, bio-compatible and lightweight respiration sensor. The sensor consists of highly oriented carbon nanotube (HO-CNT) films embedded between electro-spun polyacrylonitrile (PAN) layers. By aligning carbon nanotubes between the PAN layers, the sensor exhibits a high sensitivity towards airflow (340 mV/(m/s)) and excellent flexibility and robustness. In addition, the HO-CNT sensor is insensitive to mechanical bending, making it suitable for wearable applications. We successfully demonstrated the attachment of the sensor to the human philtrum for real-time monitoring of the respiration quality. These results indicate the potential of HO-CNT flow sensor for ubiquitous personal health care applications

Experimental cultivation of Spirulina platensis using My An mineral water, Thua Thien Hue province

Spirulina platensis was experimentally cultivated by semi-continuous method at 20m2 scale pilot to effectively use the available bicarbonate and minerals of the My An mineral water, Phu Vang district, Thua Thien Hue province, and reduce production cost. Analyses of My An water quality showed that this mineral water source was suitable to cultivate Spirulina Platensis after removing H2S. The average algal yield reached to 10gDW/m2.day. The obtained algal biomass contained high nutrient compositions and was a suitable source for functional food (68.32 % protein, 7.32 % lipids containing Omega-3 and Omega-6, and low heavy metal concentration). The obtained results indicated that the My An mineral water source was indeed a suitable water source for producing Spirulina platensis biomass as a functional food