Assessing and improving rational antimicrobial use in urban and rural health care facilities in Vietnam

The global problem of antimicrobial resistance (AMR) is particularly pressing in developing countries including Vietnam, where the infectious disease burden is high and cost constrains the replacement of older antimicrobials with newer, more expensive ones. Along with surveillance and infection control, responsible use of antimicrobials is one of the main objectives of the Vietnam National Action Plan on combating AMR. This thesis aims to get a better understanding of how antimicrobials are used in the Vietnamese community and how its use can be improved, to tailor evidence-based interventions and inform policies in controlling AMR. To assess the current situation of community access and use of antimicrobials and identify determinants associated with current practice, an observational study was conducted in 30 private pharmacies in northern Vietnam. This study was followed by a randomised controlled trial (RCT) to evaluate a point of care (POC) C-reactive protein (CRP, a biomarker of inflammation) test in reducing unnecessary antimicrobial prescribing for patients with non-severe acute respiratory infections (ARI) and analysis of the economic impact and acceptance of this intervention among users. In private pharmacies, profit incentives coupled to poor knowledge about AMR are key drivers of over the counter dispensing of antimicrobials regardless the existence of regulations. Using a simple rapid blood test to identify customers who do not benefit from antimicrobial therapy would be a potential solution. Primary healthcare stations where over-prescription of antimicrobials for self-limiting infections are common, were chosen for the intervention. CRP POC testing reduced unnecessary AB use for ARI patients without compromising patient’s recovery. This supports and extends findings from European trials by showing that such a stewardship approach is applicable even in resource constrained settings. However, there were several obstacles identified among users regarding test adherence associated with large between-site heterogeneity that need to be addressed to maximize the intervention’s effect in the future. More importantly, our cost analysis indicated that to encourage adoption at scale, proper funding mechanisms to balance the invested costs and achieve global impact on AMR is recommended. In summary, antimicrobial use in Vietnam is largely uncontrolled both in the community and the healthcare system leading to overuse and over-prescription for non-severe ARI. Use of commercially available CRP tests can be an effective, scalable and economically viable approach, even in highly resource-constrained settings. For the future, we are looking at ways to optimise use of POC biomarker testing in primary healthcare and private pharmacy setting. The potential for biomarker based tests to be combined with rapid pathogen detection, enhancing test algorithm adherence, use of CRP tests with equal financial incentives as as selling of antimicrobials and introducing pay for performance mechanisms may be crucial parts for optimisation

PRODUCTION OF POLYCLONAL ANTIBODIES AGAINST RECOMBINANT VP6 ANTIGEN OF ROTAVIRUS

Rotavirus is the most common cause of diarrhea in infants and young children under five years old. The VP6 protein of rotavirus was considered as an important antigen in the development of novel vaccine generation and diagnostic tools. Polyclonal antibodies of VP6 antigen could be used to generate a rapid test based on the lateral flow immunoassay. In the present study, we showed the results of synthesis of polyclonal antibodies against recombinant VP6 protein of rotavirus. Recombinant VP6 protein was strongly produced by E. coli in suitable conditions. The properties of recombinant VP6 protein were characterized by Western blot and ELISA methods. Pure recombinant VP6 protein was used as an antigen to inject into the rabbits. The recombinant VP6 protein was highly immunogenic in rabbits. Anti-VP6 antibodies were purified from the rabbit serum using the Protein A affinity chromatography. The specificity of the antibody towards its antigen was characterized by Western blot and ELISA immunoassay. The purity of antibody was reached as 97 %. The efficiency of antibody production in rabbit was 3.94 mg/ml serum. The amount and quality of the obtained anti-rotavirus VP6 antibody was suitable for application in the development of the diagnostic kits

Strain Engineering of Magneto-optical Properties in C3_3B/C3_3N van der Waals Heterostructure

Carbon-based bilayer van der Waals (vdW) materials are attracting much attention due to their predicted interesting physical properties. Here, we theoretically investigate electronic and optical properties of C$_3$B/C$_3$N vdW heterostructure (HTS) under external magnetic field and mechanical strain. The tight-binding model of the system is constructed to include the strain-induced modification of the hopping interactions. The influence of a uniform perpendicular magnetic field is included by using the Peierls substitution method. We observe the intriguing electronic and optical characteristics of the HTS under mechanical strain, covering the band inversion, alteration of band gap and optical gap, distortion of band-edge states, as well as significant enhancement of optical absorption. Furthermore, the interplay between external magnetic field and biaxial strain leads to exotic features of quantization and optical spectra. This work provides important information for the comprehension of the engineering of materials by external effects. Our study suggests that C$_3$B/C$_3$N vdW HTS is a promising candidate for next-generation electronic and optoelectronic devices

Magnetoplasmons in magic-angle twisted bilayer graphene

The magic-angle twisted bilayer graphene (MATBLG) has been demonstrated to exhibit exotic physical properties due to the special flat bands. However, exploiting the engineering of such properties by external fields is still in it infancy. Here we show that MATBLG under an external magnetic field presents a distinctive magnetoplasmon dispersion, which can be significantly modified by transferred momentum and charge doping. Along a wide range of transferred momentum, there exist special pronounced single magnetoplasmon and horizontal single-particle excitation modes near charge neutrality. We provide an insightful discussion of such unique features based on the electronic excitation of Landau levels quantized from the flat bands and Landau damping. Additionally, charge doping leads to peculiar multiple strong-weight magnetoplasmons. These characteristics make MATBLG a favorable candidate for plasmonic devices and technology applications

Polarizability and Impurity Screening for Phosphorene

Using a tight-binding Hamiltonian for phosphorene, we have calculated the real part of the polarizability and the corresponding dielectric function, Re[ ϵ q ω ], at absolute zero temperature (T = 0 K) with free carrier density 10 13 / cm 2 . We present results showing Re[ ϵ q ω ] in different directions of the transferred momentum q. When q is larger than a particular value which is twice the Fermi momentum kF, Re[ ϵ q ω ] becomes strongly dependent on the direction of q . We also discuss the case at room temperature (T = 300 K). These results which are similar to those previously reported by other authors are then employed to determine the static shielding of an impurity in the vicinity of phosphorene

STUDY THE ANTICANCER MECHANISM OF THE PROMISSING COMPOUND 2B2D BY USING MICROARRAY TECHNIQUE

Being a modern technique with the ability of studying, discovering, probing and analyzing the  expression  of  thousands  genes,  even  the  whole  genome  in  the  only  one  experiment, microarray  proved  to  be  a  powerful  tool  for  cancer  research  especially  at  molecular  level. Employing  the  potential  anticancer  compound  1-(5,7-dimetoxy-2,2-dimetyl-2H-cromen-8-yl)-but-2-en-1-on  (2B2D  in  short) and LU-1,  the human  lung cancer cells as  research objects, we successfully  hybridized  the  cy3/5  incorporated  cDNA  with  Phalanx  HOV5  microarray.  The results  showed  742  genes  that  got  effected with  equal  or  over  two  folds  change  under  2B2D treatment.  Among  -  those,  386  genes  were  up-regulated  while  the  other  356  were  down-regulated. The Nuclear  factor  (erythroid-derived  2,  regulatory  factor X  domain  containing  1, fibroblast  growth  factor  receptor  3  (achondroplasia,  thanatophoric  dwarfism)  and  E2F transcription factor 8 genes were the most stimulated by our compound. The genes that named as Solute carrier  family 7  (cationic amino acid  transporter,  system) member 11,  kelch-like 24 and Hypothetical LOC344887 were the most down in action