Formation and Characterization of Vegetable Oil Microemulsions and Their Application in Oilseed Extraction and Biofuel

Microemulsions are thermodynamically stable dispersions of oil and water stabilized by a film of surfactants and/or co-surfactants. They have numerous applications in food, oilseed extraction, drug and cosmetic delivery, enhanced oil recovery, biofuels, etc. Microemulsion formation of vegetable oils at ambient conditions (temperature and pressure) and without the addition of co-oil and/or alcohols is challenging at best. Undesirable phases, such as macroemulsions, liquid crystals and sponge phases, are often encountered when formulating these microemulsions. The goal of this dissertation is to formulate vegetable oil microemulsions using a novel class of surfactants, called extended-surfactants combining with hydrophilic/hydrophobic linker system, and to explore their uses in oilseed extraction and bio-renewable fuel applications. Extended-surfactants are a relatively new type of surfactant with propoxylate (PO) and/or ethoxylate (EO) groups inserted between the hydrophilic head and the hydrophobic alkyl chain of the surfactant molecule. This unique structure of extended-surfactants enables them to produce ultralow interfacial tension with vegetable oils at ambient condition. Environmentally friendly vegetable oil microemulsions were successfully formed without the addition of co-oil/alcohol at ambient temperature. These microemulsions are particularly useful in food, drug and cosmetic applications. Owing to the ultralow interfacial tension reduction between the vegetable oil and aqueous extended-surfactant solution at relatively low surfactant concentration, we have demonstrated that the aqueous extended-surfactant-based method is a viable alternative for vegetable oil extraction as in batch study. The oil quality produced from the aqueous extended-surfactant based method was found to be comparable or even superior to that obtained from hexane-based extraction. Next, we have designed and investigated a semi-continuous pilot-scale study of the aqueous extended-surfactant-based method for vegetable oil extraction. The total oil recovery after two extraction stages was approaching the result obtained from the batch study; however, the free oil recovery was lower. We have shown that the aqueous surfactant based method for oilseed extraction is superior to that of aqueous extraction method and enzyme-assisted extraction method. The last part of the dissertation demonstrated the use of reverse micellar microemulsions of vegetable oil/diesel blend as an alternative to diesel fuel. With appropriate surfactant and co-surfactant systems, we were able to formulate canola and algae/diesel blend microemulsion fuels with fuel properties such as viscosities, cloud points and pour points that satisfy the ASTM standards. The global CO pollutant and radiation emissions of all formulated microemulsion fuels were superior to DF and biodiesel. NOx emissions were lower in the blend containing no nitrate additives, but were higher than DF in the presence of nitrate additives. Thus, these results show that microemulsification is a viable technology for producing biofuels without chemical reactions and that fuel properties can be adjusted via formulation variables

The local uniform convergence of positive harmonic function sequence

The Harnack distance on space  and its conformal invariance were constructed and studied by Herron. In this paper, we obtain the Harnack distance on domains  in . Then, we use this concept to investigate some properties of the positive harmonic function class. These results are obtained in the complex plane, so it is advantageous to take some tools of the complex analysis. The main result of this paper is the property of the local uniform convergence of the positive harmonic sequences on a domain in the complex plane.The Harnack distance on space  and its conformal invariance were constructed and studied by Herron. In this paper, we obtain the Harnack distance on domains  in . Then, we use this concept to investigate some properties of the positive harmonic function class. These results are obtained in the complex plane, so it is advantageous to take some tools of the complex analysis. The main result of this paper is the property of the local uniform convergence of the positive harmonic sequences on a domain in the complex plane

ASSESSING THE POTENTIAL OF COMMUNITY-BASED ECOTOURISM TOWARD SUSTAINABLE DEVELOPMENT: A CASE STUDY IN TUA CHUA KARST PLATEAU – DIEN BIEN – VIET NAM

Tua Chua Karst Plateau - a living area of the Mong ethnic group with spectacular natural landscapes, cool weather, and unique indigenous cultural values. They are all prerequisites for tourism development. This study aims to evaluate the potential of community-based ecotourism development in the Tua Chua Karst Plateau. This research uses the AHP method. Evaluation criteria include (i) uniqueness of natural landscape, (ii) indigenous cultural value, (iii) stakeholder engagement, (iv) local tourism development policy, (v) quality of infrastructure, (vi) quality of tourism facilities, (vii) accessibility, (viii) connectivity. The evaluation system includes eight criteria that have classified tourism resources according to each resource point and identified suitable internal and external potentials to exploit the geological value of the plateau and preserve indigenous culture. Results of this study reveal that the indigenous cultural values, the participation of local communities, and the uniqueness of the natural landscape have an important impact on the development of ecotourism. Tua Chua Karst Plateau has great potential for community-based ecotourism development with 14 tourist resource sites, of which 8 are highly appreciated

Antibiotic Resistance Profile and Methicillin-Resistant Encoding Genes of Staphylococcus aureus Strains Isolated from Bloodstream Infection Patients in Northern Vietnam

Background:  Evaluating the antibiotic susceptibility and resistance genes is essential in the clinical management of bloodstream infections (BSIs). Nevertheless, there are still limited studies in Northern Vietnam. AIM: This study aimed to determine the antibiotic resistance profile and methicillin-resistant encoding genes of Staphylococcus aureus (S. aureus) causing BSIs in Northern Vietnam. METHODS: The cross-sectional study was done from December 2012 to June 2014 in two tertiary hospitals in Northern Vietnam. Tests performed at the lab of the hospital. RESULTS:  In 43 S. aureus strains isolating, 53.5 % were MRSA. Distribution of gene for overall, MRSA, and MSSA strains were following: mecA gene (58.1 %; 95.7%, and 15%), femA gene (48.8%, 47.8%, and 50%), femB gene (88.4%, 82.6%, and 95%). Antibiotic resistance was highest in penicillin (100%), followed by erythromycin (65.1%) and clindamycin (60.5%). Several antibiotics were susceptible (100%), including vancomycin, tigecycline, linezolid, quinupristin/dalfopristin. Quinolone group was highly sensitive, include ciprofloxacin (83.7%), levofloxacin (86%) and moxifloxacin (86%). CONCLUSION:  In S. aureus causing BSIs, antibiotic resistance was higher in penicillin, erythromycin, and clindamycin. All strains were utterly susceptible to vancomycin, tigecycline, linezolid, quinupristin/dalfopristin

Antibiotic Resistance Profile and Diversity of Subtypes Genes in Escherichia coli Causing Bloodstream Infection in Northern Vietnam

BACKGROUND: Evaluating the antibiotic susceptibility and resistance genes is essential in the clinical management of bloodstream infections (BSIs). But there are still limited studies in Northern Vietnam. AIM: The aim of the study was to determine the antibiotic resistance profile and characteristics of subtypes genes in Escherichia coli causing BSIs in Northern Vietnam. METHODS: The cross-sectional study was done in the period from December 2012 to June 2014 in two tertiary hospitals in Northern Vietnam. Tests were performed at the lab of the hospital. RESULTS: In 56 E. coli strains isolating 39.29 % produced ESBL. 100% of the isolates harbored blaTEM gene, but none of them had the blaPER gene. The prevalence of ESBL producers and ESBL non-producers in blaCTX-M gene was 81.82%, and 73.53%, in blaSHV gene was 18.18% and 35.29%. Sequencing results showed three blaTEM subtypes (blaTEM 1, 79, 82), four blaCTX-M subtypes (blaCTX-M-15, 73, 98, 161), and eight blaSHV subtypes (blaSHV 5, 7, 12, 15, 24, 33, 57, 77). Antibiotic resistance was higher in ampicillin (85.71%), trimethoprim/sulfamethoxazole (64.29%) and cephazolin (50%). Antibiotics were still highly susceptible including doripenem (96.43%), ertapenem (94.64%), amikacin (96.43%), and cefepime (89.29%). CONCLUSION: In Escherichia coli causing BSIs, antibiotic resistance was higher in ampicillin, trimethoprim/sulfamethoxazole and cephazolin. Antibiotics was highly susceptible including doripenem, ertapenem, amikacin, and cefepime

The Role of Serial NT-ProBNP Level in Prognosis and Follow-Up Treatment of Acute Heart Failure after Coronary Artery Bypass Graft Surgery

BACKGROUND: After coronary artery bypass graft (CABG) surgery, heart failure is still major problem. The valuable marker for it is needed. AIM: Evaluating the role of serial NT-proBNP level in prognosis and follow-up treatment of acute heart failure after CABG surgery. METHODS: The prospective, analytic study evaluated 107 patients undergoing CABG surgery at Ho Chi Minh Heart Institute from October 2012 to June 2014. Collecting data was done at pre- and post-operative days with measuring NT-proBNP levels on the day before operation, 2 hours after surgery, every next 24 h until the 5th day, and in case of acute heart failure occurred after surgery. RESULTS: On the first postoperative day (POD1), the NT-proBNP level demonstrated significant value for AHF with the cut-off point = 817.8 pg/mL and AUC = 0.806. On the second and third postoperative day, the AUC value of NT- was 0.753 and 0.751. It was statistically significant in acute heart failure group almost at POD 1 and POD 2 when analyzed by the doses of dobutamine, noradrenaline, and adrenaline (both low doses and normal doses). CONCLUSION: Serial measurement of NT-proBNP level provides useful prognostic and follow-up treatment information in acute heart failure after CABG surgery

De novo copy number variations in candidate genomic regions in patients of severe autism spectrum disorder in Vietnam

Autism spectrum disorder (ASD) is a developmental disorder with a prevalence of around 1% children worldwide and characterized by patient behaviour (communication, social interaction, and personal development). Data on the efficacy of diagnostic tests using copy number variations (CNVs) in candidate genes in ASD is currently around 10% but it is overrepresented by patients of Caucasian background. We report here that the diagnostic success of de novo candidate CNVs in Vietnamese ASD patients is around 6%. We recruited one hundred trios (both parents and a child) where the child was clinically diagnosed with ASD while the parents were not affected. We performed genetic screening to exclude RETT syndrome and Fragile X syndrome and performed genome-wide DNA microarray (aCGH) on all probands and their parents to analyse for de novo CNVs. We detected 1708 non-redundant CNVs in 100 patients and 118 (7%) of them were de novo. Using the filter for known CNVs from the Simons Foundation Autism Research Initiative (SFARI) database, we identified six CNVs (one gain and five loss CNVs) in six patients (3 males and 3 females). Notably, 3 of our patients had a deletion involving the SHANK3 gene–which is the highest compared to previous reports. This is the first report of candidate CNVs in ASD patients from Vietnam and provides the framework for building a CNV based test as the first tier screening for clinical management

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

Synthesis (N,)C,N - complexes of tellurium as precursors for novel heterecycles

Tato práce se zabývá přípravou nových C,N- a N,C,N-chelatovaných tellurnatých a telluričitých sloučenin s vysokou mírou Lewisovské kyselosti na centrálním atomu Te a dále jejich hydrolyzní reaktivitou za vzniku nových heterocyklických telluroxanů. Těm je věnována teoretická část, která stručně shrnuje jejich strukturní motivy a vzájemné přeměny mezi nimi.This work deals with the synthesis of new C,N- a N,C,N-chelated tellurium(II) and tellurium(IV) compounds with high Lewis acidity at the central Te atom and with their reactivity focused on hydrolysis with the intention of synthesis of new heterocyclic telluroxanes. Chemistry of known telluroxanes is summarized in the theoretical part of this work where theirs structural motifs and mutual transformations are briefly discussed.Fakulta chemicko-technologickáStabilita připravených sloučenin na vzduchu, nová studie porovnání Penicilinu se sloučeninami telluru, toxicita použitých reagentů.Dokončená práce s úspěšnou obhajobo

The local uniform convergence of positive harmonic function sequence

The Harnack distance on space  and its conformal invariance were constructed and studied by Herron. In this paper, we obtain the Harnack distance on domains  in . Then, we use this concept to investigate some properties of the positive harmonic function class. These results are obtained in the complex plane, so it is advantageous to take some tools of the complex analysis. The main result of this paper is the property of the local uniform convergence of the positive harmonic sequences on a domain in the complex plane