Effect of chromium substituted on structural and magnetic characterization lithium ferrite nanoparticles

In this work, we present a structural, morphology and magnetic study of the Li0.5Fe2.5-xCrxO4 spinel nanoparticles (x = 0, 0.5, 0.75, 1, and 1.25) with mean particle size of 20-30 nm prepared by sol-gel method. The lattice constants and the size of particle decrease with increasing Cr concentration. In these samples, the preference of Cr3+ and Li+ ions in the octahedral sites and a small degree of site-interchange between Li+ in the octahedral sites and Fe3+ in the tetrahedral sites were found which increases with increasing the Cr content. A decrease of magnetization due to the spin disorder in the surface layer of the particles was observed. The spontaneous magnetization at 5K suggests the Néel type of magnetic ordering in these samples. The magnetic coercivity is discussed in terms of particle size, morphology and chromium substitution. Keywords. Chromium substitution, sol-gel method, nanoparticles, lithium ferrite

Synthesis of ZnO nanorod for immunosensor application

This paper reported a facile method to synthesize ZnO nanorods for immunosensor application. The ZnO nanorods were synthesized by hydrothermal reaction. Synthesis time affecting on morphology of nanorods was also studied. The immobilization of anti-rotavirus onto ZnO nanorod-deposited sensor was performed via absorption method. The electrochemical responses of the immunosensor were studied by cyclic voltammetry (C-V) method with [Fe(CN)6]3−/4− as redox probe. A linear decreased response in C-V for cell of rotavirus concentration was found in the range of 7.8×105 CFU/mL to 7.8×108 CFU/mL. The detection limit of the immunosensor was 7.8×105 CFU/mL. The results indicated application of ZnO nanorod sensor for label-free real-time detection of a wide dynamics range of biological species

Fabrication of silver-nanoparticles-embedded polymer masterbatchs with excellent antibacterial performance

In the present work, a versatile and effective synthesis method of the silver-nanoparticles-embedded polyethylene (PE)-based polymer masterbatchs was demonstrated. Antibacterial investigations revealed that the nano-silver masterbatchs consisting of oleate capped silver nanoparticles dispersed in PE polymer matrix exhibited excellent antibacterial performance against Gram-negative Escherichia Coli (E.coli) and Staphylococcus aureus (S. aureus) bacteria.  A complete inhibition in bacteria growth was found at a silver nanoparticles concentration as low as 600 ppm. The origin of bactericidal effect and interaction mechanism of the stabilized silver nanoparticles with the Gram-negative E. coli and Gram-positive S. aureus bacteria can be understood in the light of electron microscopic observation. These advances make the synthesized nano-silver masterbatchs ideal for mass production of effectively antibacterial green products in medical, biological and industrial sectors. The type of polymer resin and silver concentration can be adjusted depending on the application area

Electrochemical DNA sensor for label-free soybean transgenic detection

This paper describes the development of electrochemical label- free DNA sensor for detection of transgenic in Round–up Ready Soybean (herbicide tolerance). Two pairs of electrodes which the optimized dimension is 70µm x 30µm (the width of electrode x inter-distance between fingers), were fabricated on a chip for differential measures. The DNA probe (35S 5’-GCT CCT ACA AAT GCC ATC A-3) was designed in such a way that it can hybridize with the CaMV 35S promoter of Roundup Ready soybean. The DNA was immobilized on the surface of the sensor by the mean of (3-aminopropyl)triethoxysilane (APTS) polymer. The response time of DNA sensor is less than 1 second; in case of 100% matching level, the sensitivity is 2 mV/µM. The activity of DNA sensor remains unchanged after 9 months of storage at -4oC in DI water. Some random soybean samples were collected, extracted and tested by the DNA sensor and the results were well matched with the of PCR method

Genetic variation and outcrossing rate of Dipterocarpus dyeri in the Tan Phu tropical rain forest (Dong Nai), Vietnam

Dipterocarpus dyeri (Dipterocarpaceae) is widely distributed in lowland rainforests in southeastern Vietnam. Due to over- exploitation and habitat destruction in the 1980s and 1990s, this species is listed as threatened. Understanding the genetic variation and mating rate among D. dyeri population that occurs in forest patches is necessary to establish effectively conservation strategies for this species. To conserve the species in tropical forests, genetic diversity and mating rate were investigated using eight microsatellites (single sequence repeat, SSR) as markers. All of the eight loci were polymorphic. A total of 36 different alleles were observed across the loci screened. The SSR data indicated high genetic diversity (NA = 4.5; HO = 0.542 and HE = 0.667) and high inbreeding value, FIS= 0,182. The mating system parameters were determined using the mixed mating model and the results indicated high outcrossing rate (tm=0.81 and ts=0.675) and lowselfing rate (0.19). Difference of tm-ts value indicated that inbreeding contributed to selfing rate for this species in the Tan Phu tropical rain forest. The results reflected that D. dyeri habitat in this area has been restored and the number of individuals was high, about 500 individuals. However, seedlings were not found so far in this study. These results indicated the importance of conserving of the genetic resources of Dipterocarpus dyeri species in the Tan Phu rain forest. The conservation strategy should include an establishment of an ex-situ conservation site with new big population for this species from all genetic groups, which might improve its fitness under different environmental stresses. 

Red light emission of Mn doped beta-tricalcium phosphate -Ca3(PO4)2

This paper is the first report on the red light emission of manganese (Mn) doped beta-tricalcium phosphate (b-Ca3(PO4)2, TCP) synthesis by co-precipitation method followed by thermal annealing. The annealed Mn doped TCP phosphor showed dominant spheres with a diameter of about 500 nm. The influences of the Mn concentration, annealing temperature, and atmospheres on the photoluminescence intensities of the phosphors were investigated and the results indicate that the annealing temperatures and Mn concentrations are the main factors. The phosphor showed visible emission peaks appeared at about 660 nm and 580 nm results in from the 4T1-6A1 transitions within Mn2+ ion. The Mn-TCP phosphor may serve as a candidate for light-emitting diode application in agriculture lighting. Keywords. Hydroxyapatite; manganese; luminescence; tricalcium phosphate

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

Successful Psoriasis Treatment Using NB-UVB with Methotrexate: The Vietnamese Experience

AIM: To compare the effectiveness of narrowband ultraviolet B (NBUVB) and oral methotrexate (MTX) to oral MTX alone in Vietnamese psoriasis patients, from May 2016 to May 2018. METHODS: We conducted a non-randomized trial on 70 patients with plaque-type psoriasis of moderate to severe. Thirty-five patients apply NBUVB once/day in 5 days/week for 4 weeks plus oral MTX 7.5 mg/week and 35 patients oral MTX 7.5 mg/week and both two groups treatment for 3 months. The extent of the lesion was assessed by the Psoriasis Area and Severity Index (PASI). RESULTS: The proportion of decreasing PASI was comparable (68.49% in NBUVB and MTX versus 57.62% in MTX alone); p < 0.05. Inside, good 28.58%, moderate 68.57% and poor 2.85% in NBUVB and MTX better than good 2.85%, moderate 71.4% and poor 25.72% in MTX alone; p < 0.05. The recurrence rate after 24 months of the NBUVB and MTX group (42.9%) was lower than the MTX alone group (71.4%); p < 0.05. CONCLUSION: NBUVB and oral MTX have affected treatment with chronic plaque psoriasis better than oral MTX alone

Efficacy of Oral Itraconazole in the Treatment of Seborrheic Dermatitis in Vietnamese Adults Patients

AIM: This longitudinal study aims to evaluate the efficacy of oral itraconazole in the treatment of seborrheic dermatitis in Vietnamese patients. METHODS: Thirty patients were enrolled at National Hospital of Dermatology and Venereology, Hanoi, Vietnam and were treated with oral itraconazole (200 mg daily in 14 days followed by 200 mg weekly in 4 weeks). The clinical severity was assessed by a four-parameter scoring system. All patients completed the six-week regimen with good adherence. RESULTS: At the week 2nd, 70% of the patients had moderate to severe diseases. At the week 6th, 63.4% of the patients achieve clearance of the lesions, and none had severe disease. No side effects were reported. CONCLUSION: Oral itraconazole can be an option for seborrheic dermatitis because of good efficacy, safety profile and adherence

Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions