Background

To respond to the dual HIV and injecting drug use epidemic, Vietnam has implemented methadone maintenance treatment (MMT) nationwide since 2010 and decentralized it to primary care (i.e. commune health centers) since 2015. The study aims to explore the challenges that Vietnamese community health workers (CHW) at commune health centers encounter in providing MMT and the factors associated to these challenges.

Methods

This study had a mixed method design. We used two types of data in this study. For the sub-study 1, we used the secondary data from a quantitative survey conducted in Vinh Phuc and Phu Tho provinces among 300 CHWs who did not provide MMT at the time of the study. For the sub-studies 2 and 3, we collected quantitative and qualitative primary data from Dien Bien province. We conducted a quantitative survey among 276 CHWs including both MMT providers and non-MMT providers. From this sample, we selected 26 MMT providers with various characteristics for in-depth interviews.

Results

In the sub-study 1, the mean score of CHWs’ interaction with PWUD 36.4 (SD 8.8) on a scale of 60. The interaction between CHW not providing MMT and people who use drugs (PWUD) was negatively associated with their stigmatizing attitude towards PWUD (β = -0.84, 95% CL: -1.05; -0.63) after adjusting for their background (gender, education level, job position and years of working experience) and job-related characteristics (perceived risk and challenges when working with PWUD, job satisfaction and empathy towards PWUD). In the sub-study 2, 114 (41.3%) CHW had ever provided MMT services. Better MMT knowledge was associated with higher levels of confidence in providing MMT services among CHW who had no experience with MMT program (β=0.90, 95%CL: 0.29; 1.51), not among those who had experiences. On the other hand, technical support in working with PWUD was associated with a higher level of confidence in providing MMT services for both groups (β=0.71, 95%CL: 0.35; 1.08 and β=0.58, 95%CL: 0.19; 0.96 among CHWs who had ever and who had never worked in MMT, respectively). In sub-study 3, the perceived challenges for MMT provision included lack of confidence and motivation to provide MMT, inadequate human resource, lack of institutional support, insufficient technical support, lack of referral resources and additional support for patients, lack of policies to support the MMT program at CHCs and to protect service providers.

Conclusion

CHWs in Vietnam faced several challenges in working with PWUD and providing MMT services at primary care settings. Supportive policies and tailored interventions should be developed at different levels to ensure the quality and effectiveness of the MMT decentralization program.

Thermoelectric (TE) materials have been attractive to several research groups all over the world for their ability of directly converting thermal energy into electrical energy by the Seebeck Effect, and vice versa by the Peltier Effect. Due to their reliability and scalability, TE materials can be incorporated into devices for power generation or for cooling applications. Skutterudites have a complex crystalline structure in which the voids in the structure can be filled with foreign atoms. This doping technique has been shown to improve the TE performance of these "filled" skutterudite materials by disrupting the thermal conductivity without significantly impacting the electrical conductivity. Several studies have been done on filled CoSb3-based skutterudites and high ZT values have been obtained for these materials around 6000C. However, for thermoelectric applications that require higher operating temperatures, the more refractory IrSb3 with a peritectic decomposition at 11360C (1409 K) offers an advantage over CoSb3, which decomposes at 8740C (1147 K). Using the traditional synthesis method of melting, quenching, then annealing stoichiometric amounts of the elements to produce n-filled skutterudites, the obtained filling fraction was found to be significantly lower than the nominal filling fraction due to the high reactivity, or sometimes the high volatility, of the elemental fillers. In this experiment, we explored the effects of pre-reacting the reactive metal filler element with one of the elements in the skutterudite structure and utilized this precursor for the synthesis of the filled skutterudites to compare the relative successes of achieving targeted filling percentages of the voids in the structure. KyIr4Sb12 samples were synthesized using both the pure filler element, as well as the pre-reacted K-Sb compound. The phase purities, lattice parameters and elemental compositions were analyzed for each sample, calculated using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and electron microprobe analysis (EPMA), respectively. Their thermoelectric properties were also measured and calculated at room temperature and as a function of temperature ranging from room temperature to about 7500C (1023 K). The preliminary results obtained suggest that pre-reacting the potassium with antimony results in higher percentages of phase impurities and less efficient void filling in IrSb3 skutterudite. The highest ZT among all potassium-filled samples synthesized was measured to be 0.28 at 5000C (773 K) for K0.24Ir4Sb12. The data suggest that the cumulative thermoelectric properties of potassium filled IrSb3 are not as favorable as those IrSb3-based skutterudites filled with other atoms such as Ba or Eu. However, some of the potassium-filled samples achieved high room temperature carrier concentrations, similar to those seen in barium-filled samples, indicating that the potassium effectively participates in doping the structure. This work has compared and contrasted two methods for incorporating potassium fillers in the void spaces of IrSb3 skutterudite. While the ZT of potassium-filled samples was less than required for practical applications, this work does suggest that potassium may be useful in tuning electrical properties in samples that employ multiple element filling.

The relationship between the lattice parameter and the filling fraction was also studied on barium-filled and europium-filled IrSb3 skutterudite samples. A higher nominal filling fraction acquired a higher EPMA filling fraction and a higher lattice parameter until the filling fraction limit was reached. While barium displayed higher filling efficiency, europium possessed higher filling fraction limit. These preliminary results suggest that the optimization of multiple element filling to produce higher ZT is very obtainable with further studies on different single fillers.

Background

Methods

Results

Conclusions