RESUMO
Sulfur is one of the inorganic elements used by plants to develop and produce phytoalexin to resist certain diseases. This study reported a method for preparing a material for plant disease resistance. Sulfur nanoparticles (SNPs) stabilized in the chitosan-Cu2+ (CS-Cu2+) complex were synthesized by hydrolysis of Na2S2O3 in an acidic medium. The obtained SNPs/CS-Cu2+ complex consisting of 0.32% S, 4% CS, and 0.7% Cu (w/v), contained SNPs with an average size of ~28 nm as measured by transmission electron microscopy images. The X-ray diffraction pattern of the SNPs/CSCu2+ complex showed that SNPs had orthorhombic crystal structures. Interaction between SNPs and the CS-Cu2+ complex was also investigated by ultraviolet-visible. Results in vitro nematicidal effect of materials against Meloidogyne incognita showed that SNPs/CS-Cu2+ complex was more effective in killing second-stage juveniles (J2) nematodes and inhibiting egg hatching than that of CS and CS-Cu2+ complex. The values of LC50 in killing J2 nematodes and EC50 in inhibiting egg hatching of SNPs/CS-Cu2+ complex were 75 and 51 mg/l, respectively. These values were lower than those of CS and the CS-Cu2+ complex. The test results on the nematicidal effect against M. incognita on coffee pots showed that the SNPs/CS-Cu2+ complex was 100% effective at a concentration of 150 mg/l. Therefore, the SNPs/CS-Cu2+ complex could be considered as a biochemical material with potential for agricultural applications to control root-knot nematodes.
RESUMO
Deoiled coconut cake powder (DCCP) was hydrolyzed to reduce the ratio of insoluble/soluble dietary fiber (RIS) by partially converting insoluble dietary fiber to soluble using Celluclast 1.5 L, a commercial cellulase preparation in citrate buffer medium. Firstly, the influence of citrate buffer amount, enzyme concentration, pH, and retention time on the enzymatic hydrolysis efficiency was investigated. Then, response surface methodology (RSM) was employed to optimize the process in which the insoluble and soluble dietary fiber contents were the responses. The results revealed that 10.3 g buffer/g of materials, 3.7 U/g of the materials, and 60 min of retention time were the optimal conditions for the enzymatic hydrolysis to obtain the insoluble and soluble contents of 68.21%db and 8.18%db, respectively. Finally, DCCP or hydrolyzed DCCP (HDCCP) was partially substituted for wheat flour at different replacement ratios in a cookie recipe at 0, 10, 20, 30, and 40%. The cookies with a 10% replacement ratio of hydrolyzed deoiled coconut cake powders had a lower RIS by more than two folds those of DCCP and had the same sensorial score as the control sample. This study proposed that Celluclast 1.5 L effectively reduced RIS by partially converting insoluble to soluble dietary fiber, improving the soluble dietary fiber content in fiber-enriched cookies.
RESUMO
BACKGROUND: Microsurgery is a highly specialized skill that requires advanced training. This is a recount of the 12-year development of Hanoi National Hospital of Odonto-Stomatology (NHOS) from a basic plastic surgery unit to a high-volume, subspecialized reconstructive center. METHODS: We present a 12-year retrospective account of the development of NHOS with a brief summary of microsurgical reconstructive outcomes. RESULTS: From 2008 to 2020, NHOS has performed 665 microsurgical flaps for reconstruction of various maxillomandibular defects. In the pioneering stage (2008-2011), without surgical microscopes, all five free flaps failed. After acquiring a microscope and mentoring from Hanoi's 108 Military Hospital, mandibular bone defect reconstruction with free fibula flaps had 85% success rate. In the growth stage (2012-2015), reconstruction advanced toward more complex defects requiring soft tissue, with a 98.7% success rate. The maturation stage (2016-2020) focused on refinement of reconstructive service to provide subspecialized care for malignant head and neck cancer patients with help from Taiwan's E-Da Hospital and Operation Smile's charity program. The charity mission trips were structured to facilitate good quality teaching rather than hit a quantitative goal of the number of surgeries done. And with a success rate of 99.4%, we have begun further education of the plastic surgery community in Vietnam. CONCLUSIONS: Our rapid 12-year maturation into a high-volume, subspecialized microsurgical center is the embodiment of the generous efforts of many international friends who invested their time and expertise. And we highly recommend charity mission trips to adopt the "training the trainers" concept to maximize lasting, local impact.
RESUMO
In order to discover new antibacterial agents, series of 2-salicyloylbenzofuran derivatives were designed, synthesized and evaluated for their antibacterial activities against three Gram-(+) strains (methicillin-sensitive Staphylococcus aureus (MSSA) ATCC 29213, methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, and Streptococcus faecalis (S. faecalis) ATCC 29212) and one Gram-(-) strain (Escherichia coli (E. coli) ATCC 25922). The 2-salicyloylbenzofuran heterocycles were generated by Rap-Stoermer condensation of salicylaldehydes with phenacyl bromides and then converted to diverse O-ether derivatives by Williamson synthesis. The targeted products were screened for in vitro qualitative (zone of inhibition) and quantitative (MIC) antibacterial activities by agar well diffusion assay and agar dilution method. Amongst the compounds, those bearing carboxylic acid functional group were found to exhibit reasonable activity against Gram-(+) bacterial strains including S. faecalis, MSSA and MRSA with the most potent antibacterial agent 8h (MICs = 0.06-0.12 mM). Besides, the 2-salicyloylbenzofurans partly displayed inhibitory activity against MRSA with the best MICs = 0.14 mM (8f) and 0.12 mM (8h). Finally, the antibacterial results preliminarily suggested that the substituent bearing carboxylic acid group at salicyloyl-C2 and the bromine atoms on the benzofuran moiety seem to be the functionality necessary for antibacterial activities.
