Analysis and control of geometrically nonlinear responses of piezoelectric FG porous plates with graphene platelets reinforcement using B\'ezier extraction

In this study, we propose an effective numerical approach to analyse and control geometrically nonlinear responses for the functionally graded (FG) porous plates reinforced by graphene platelets (GPLs) integrated with piezoelectric layers. The basis idea is to use isogeometric analysis (IGA) based on the B\'ezier extraction and the $C^0$-type higher-order shear deformation theory ($C^0$-HSDT). By applying the B\'ezier extraction, the original Non-Uniform Rational B-Spline (NURBS) control meshes can be transformed into the B\'ezier elements which allow us to inherit the standard numerical procedure like the finite element method (FEM). The mechanical displacement field is approximated based on the $C^0$-HSDT whilst the electric potential is assumed to be a linear function through the thickness of each piezoelectric sublayer. The FG plate contains the internal pores and GPLs dispersed in the metal matrix either uniformly or non-uniformly according to various different patterns along the thickness of plate. In addition, to control dynamic responses, two piezoelectric layers are perfectly bonded on the top and bottom surfaces of the FG plate. The geometrically nonlinear equations are solved by the Newton-Raphson iterative procedure and the Newmark's time integration scheme. The influences of the porosity coefficients, weight fractions of GPLs as well as the external electrical voltage on the geometrically nonlinear behaviours of the plates with different porosity distributions and GPL dispersion patterns are evidently investigated through numerical examples. Then, a constant displacement and velocity feedback control approaches are adopted to active control the geometrically nonlinear static as well as the dynamic responses of the FG porous plates, where the effect of the structural damping is considered, based on a closed-loop control with piezoelectric sensors and actuators.Comment: 39 pages, 20 figure

Hazardous aerosol emissions during agriculture biomass burning season in Son La and Ba Vi regions, Vietnam

Major national emission sources are assessed by characterization of smoke pollution arising due to traditional agriculture, domestic, and cooking activities in the regions of the biggest biomass burning. Measurement campaigns were carried in Son La and Ba Vi regions, Vietnam, during the dry seasons of 2013 and 2015-2016. PM and BC monitoring, aerosol sampling, chemical speciation were conducted to evaluate ambient smoke level, to relate the characteristics of local on-field emissions to regional aerosols, and to identify the dangerous components of smoke composition. The regions Son La and Ba Vi in February-June faced severe levels of air pollution, with critical PM2.5 and PM10 concentrations up to 130 and 167 µg/m3, respectively, significantly exceeding the air quality standards. A wide range of PM mass concentrations was categorized according to the smoke level, supported by the evolution of carbon (OC, EC) fractions as well as ionic species and molecular markers. The level of PM and BC concentrations was seen to be dependent on factors such as weather conditions and precipitation. Non-acid carbonyls, carboxylates, and aliphatic carbon compounds were evolved with increasing smoke intensity, together with carbonates in coarse size fractions, indicating a large impact of smoke emissions and soil lifted up by the intense fires. On-field emissions in both smoldering and flaming phases were assessed in near-source measurements

FABRICATION, EVALUATION OF DRUG LOADING CAPABILITY AND CHARACTERIZATION OF 3D-NANO-CELLULOSE NETWORK MATERIALS PRODUCED BY BACTERIA OF FERMENTED AQUEOUS GREEN TEA EXTRACTIN SELECTED CULTURE MEDIA

Objective: The study aims for the fabrication, evaluation of drug loading capability and characterization of 3D-nano-cellulose network materials produced by bacteria of fermented aqueous green tea extract in selected culture media. Methods: 3D-nano-cellulose network (3DNC) materials can be produced by bacteria living in a fermented aqueous green tea extract. 3DNCs include nano-fibers forming networks, which are capable of drug loading to form a prolonged release therapy to improve drug bioavailability. In this study, 3DNC materials are biosynthesized by aerobic bacteria in the standard medium (SM), coconut water (CW) and rice water (RW). 3DNCs were prepared and evaluated for drug carrier using famotidine as a model drug. Famotidine was loaded in 3DNC by the absorption method. 3DNCs were characterized by using FE-SEM and FTIR spectroscopy. Results: The 3DNCs obtained from CW, and RW have the same characteristics as the 3DNC obtained from the SM, and 3DNCs can be fabricated with the desired thickness and diameter in all three types of culture media. 3DNCs absorbed famotidine in optimum condition without any difference in famotidine loading (28.2 mg) and famotidine entrapment efficiency (90 %). Investigation of the 3DNC structure using FE-SEM has shown that the cellulose fibers of 3DNC-SM and 3DNC-CW have a stable structure without structural change when loading drug under optimal condition. Conclusion: The results indicate the potential for using 3DNC-SM and 3DNC-CW to design the drug delivery system

Physicians, Primary Caregivers and Topical Repellent: All Under-Utilised Resources in Stopping Dengue Virus Transmission in Affected Households

BACKGROUND: Primary health care facilities frequently manage dengue cases on an ambulatory basis for the duration of the patient’s illness. There is a great opportunity for specific messaging, aimed to reduce dengue virus (DENV) transmission in and around the home, to be directly targeted toward this high-risk ambulatory patient group, as part of an integrated approach to dengue management. The extent however, to which physicians understand, and can themselves effectively communicate strategies to stop focal DENV transmission around an ambulatory dengue case is unknown; the matter of patient comprehension and recollection then ensues. In addition, the effectiveness of N,N-diethyl-3-methylbenzamide (DEET)-based insect repellent in protecting dengue patients from Aedes aegypti mosquitoes’ bites has not been investigated. METHODOLOGY: A knowledge, attitude and practice (KAP) survey, focusing on the mechanisms of DENV transmission and prevention, was performed using semi-structured questionnaires. This survey was targeted towards the patients and family members providing supportive care, and physicians routinely involved in dengue patient management in Southern Vietnam. An additional clinical observational study was conducted to measure the efficacy of a widely-used 13% DEET-based insect repellent to repel Ae. aegypti mosquitoes from the forearms of dengue cases and matched healthy controls. PRINCIPAL FINDINGS: Among both the physician (n = 50) and patient (n = 49) groups there were several respondents lacking a coherent understanding of DENV transmission, leading to some inappropriate attitudes and inadequate acute preventive practices in the household. The application of insect repellent to protect patients and their relatives from mosquito bites was frequently recommended by majority of physicians (78%) participating in the survey. Nevertheless, our tested topical application of 13% DEET conferred only ~1hr median protection time from Ae. aegypti landing. This is notably shorter than that advertised on the manufacturer’s label. No differences in landing time between febrile dengue cases or matched healthy controls (n = 19 experiments) were observed. CONCLUSIONS/SIGNIFICANCE: Our study identifies missed opportunities for primary care physicians to improve public health through communication of strategies that could prevent focal dengue transmission in and around a case household. We advocate better access to more efficient communication methods for physicians and auxilliary health workers, supporting to educate those at high risk of DENV transmission. Our empirical testing of a widely-available 13% DEET-based repellent was limited in its protective efficacy against Ae. aegypti mosquito bites, and therefore DENV transmission, suggesting more frequent application is necessary to be beneficial

Cognitive full-duplex relay networks under the peak interference power constraint of multiple primary users

Abstract This paper investigates the outage performance of cognitive spectrum-sharing multi-relay networks in which the relays operate in a full-duplex (FD) mode and employ the decode-and-forward (DF) protocol. Two relay selection schemes, i.e., partial relay selection (PRS) and optimal relay selection (ORS), are considered to enhance the system performance. New exact expressions for the outage probability (OP) in both schemes are derived based on which an asymptotic analysis is carried out. The results show that the ORS strategy outperforms PRS in terms of OP, and increasing the number of FD relays can significantly improve the system performance. Moreover, novel analytical results provide additional insights for system design. In particular, from the viewpoint of FD concept, the primary network parameters (i.e., peak interference at the primary receivers, number of primary receivers, and their locations) should be carefully considered since they significantly affect the secondary network performance

Using multi-temporal satellite images to evaluate the changes of vegetation index of land cover in Thai Binh Province

224pThis chapter describes the current status of Thai Binh province in Vietnam and its agricultural development plans for 2010. The environmental and economic impacts of pig production are discussed. The various stakeholders and their active involvement in agricultural production are analysed. In addition, an innovative approach to sustainable development of animal produce commodity chains in northern Vietnam, is described. The 12-month E3P Project (Environmental Protection and Pig Production) was aimed to establish baseline work for designing and implementing a geographical information system. A large proportion of unknown factors concerning the issue of effluents in the province was studied at the farm, communal and district, and on a scientific levels. These unknown factors justify the regional diagnosis presented by the E3P Project

Exploring behavioural economics: Using ‘nudge theory’ to improve the effectiveness of SafePORK interventions in Vietnam

Pork is the most popular meat consumed in Vietnam and studies have shown high (28.6-44%) Salmonella contamination rates at the point of purchase, resulting in a high incidence rate of Salmonella related food borne disease. The high microbial contamination rate is attributed to poor hygiene practice in the pork value chain and the market-based approaches to improving the safety of pork in Vietnam, or SafePORK project has designed a set of interventions to improve the standard of practice which are due to be trialled in 2019. Behavioural economics and 'nudges’ are defined as interventions with a low level of intrusiveness on personal choice which can be used to alter behaviour. While they have not yet been used for food safety in the pork value chain, some of the proposed interventions aim to alter actor’s behaviour and thus could be amenable to ‘nudging’. A previous research project to assess the potential of nudges to improve pork safety in Vietnam highlighted three main themes which could be used to influence actors within the value chain; 1) actors were most influenced by people they respected, which within the study groups were found to be veterinarians and actor’s peers, 2) actor’s reputation was regarded as an important incentive, and 3) salient visual methods of displaying information were found to be a commonly used method of delivering information in existing food safety interventions. A stakeholder workshop supported by the SafePORK project, the International Livestock Research Institute and the Royal Veterinary College was held in Hanoi to gain a better understanding of the slaughterhouse and retail processes to ascertain which nudges could be used to support the proposed interventions, and to discuss the practical aspects of implementing nudges. Participants included actors (n=32) from various parts of the pork value chain, including slaughterhouse workers, retailers, veterinarians, government officials, and researchers. During the workshop participants were separated into small groups and took part in group discussions to explore the slaughterhouse and retail processes and discuss the feasibility of using nudges to change actors' behaviours. Participants were shown several potential nudges (posters, arrows and footprints) and asked to evaluate these through discussion and a scoring exercise. After each activity a plenary session took place to allow dissemination of feedback to the entire group. The workshop found that the slaughterhouse workers and retailers appeared to be aware of the major issues surrounding foodborne disease in their industry, highlighting, during the discussions, many of the key points in the pork production chain where meat contamination with microorganisms can occur. The concept of using posters to display information was well received by the workshop participants. Both positive and negative framing of information were thought to be effective, the choice of which dependent on the target audience. However, when scored by participants, the negatively framed posters scored significantly higher than the positively framed posters, indicating a greater anticipated impact on actor’s behaviour. All participants discussed the need to have site specific photos to reflect the real context of the setting to increase engagement with the media. When considering the effect of colour on salience; red was considered dirtiest, yellow, orange, and purple considered neutral colours, and green and blue considered the cleanest colours. The participants thought that the prospect of upscaling nudges to a broader audience of retailers and consumers could be implemented but would need to be supported by competent food safety authorities. Using the findings from this workshop, site specific nudges should be created to support specific SafePORK interventions, which at this stage are likely to be in the form of informational posters. Ideally, in addition to testing the interventions in a randomly controlled trial, the nudges would be similarly tested to allow assessment of their effectiveness. Further investigation, such as trialling the use of footprints and arrows in slaughterhouse environments, is needed to ascertain the practicality of using these nudge concepts to designate clean and dirty zones

Screening of Human Tumor Antigens for CD4+ T Cell Epitopes by Combination of HLA-Transgenic Mice, Recombinant Adenovirus and Antigen Peptide Libraries

BACKGROUND: As tumor antigen-specific CD4+ T cells can mediate strong therapeutic anti-tumor responses in melanoma patients we set out to establish a comprehensive screening strategy for the identification of tumor-specific CD4+ T cell epitopes suitable for detection, isolation and expansion of tumor-reactive T cells from patients. METHODS AND FINDINGS: To scan the human melanoma differentiation antigens TRP-1 and TRP-2 for HLA-DRB1*0301-restricted CD4+ T cell epitopes we applied the following methodology: Splenocytes of HLA-DRB1*0301-transgenic mice immunized with recombinant adenovirus encoding TRP-1 (Ad5.TRP-1) or TRP-2 (Ad5.TRP-2) were tested for their T cell reactivity against combinatorial TRP-1- and TRP-2-specific peptide libraries. CD4+ T cell epitopes thus identified were validated in the human system by stimulation of peripheral blood mononuclear cells (PBMC) from healthy donors and melanoma patients. Using this strategy we observed that recombinant Ad5 induced strong CD4+ T cell responses against the heterologous tumor antigens. In Ad5.TRP-2-immunized mice CD4+ T cell reactivity was detected against the known HLA-DRB1*0301-restricted TRP-2(60-74) epitope and against the new epitope TRP-2(149-163). Importantly, human T cells specifically recognizing target cells loaded with the TRP-2(149-163)-containing library peptide or infected with Ad5.TRP-2 were obtained from healthy individuals, and short term in vitro stimulation of PBMC revealed the presence of epitope-reactive CD4+ T cells in melanoma patients. Similarly, immunization of mice with Ad5.TRP-1 induced CD4+ T cell responses against TRP-1-derived peptides that turned out to be recognized also by human T cells, resulting in the identification of TRP-1(284-298) as a new HLA-DRB1*0301-restricted CD4+ T cell epitope. CONCLUSIONS: Our screening approach identified new HLA-DRB1*0301-restricted CD4+ T cell epitopes derived from melanoma antigens. This strategy is generally applicable to target antigens of other tumor entities and to different HLA class II molecules even without prior characterization of their peptide binding motives