Introduction: Stenoses in the path of arteriovenous fistulas (AVF) for hemodialysis are a very prevalent problem and there is long experience in their treatment by percutaneous angioplasty (PTA). These procedures, however, involve non-negligible equipment requirements, exposure to radiation and intravenous contrast that are not beneficial for the patient and make their performance more complex. This study reviews our initial experience with Doppler ultrasound-guided angioplasty. Methods: Prospective cohort of patients with native AVF dysfunction due to significant venous stenosis treated by Doppler echo-guided PTA. AVF puncture, lesion catheterization, balloon localization and inflation, and outcome verification were performed under ultrasound guidance. Only one fistulography was performed before and another one after dilatation. As a control, the cases performed during the same period by the usual angiographic method were also collected. Results: Between February 2015 and September 2018, 51 PTAs were performed on native AVF, of which 27 were echogenic (mean age, 65.3 years; 63% male). The technical success rate was 96%. In 26% of cases, PTA was repeated due to residual stenosis after angiographic imaging. There were 7.3% periprocedural complications. 92% of the AVFs were punctured at 24 hours. Primary patency at 1 month, 6 months and 1 year was 100%, 64.8% and 43.6%, and assisted patency was 100%, 87.2% and 74.8%. There were no significant differences in immediate or late results with respect to angiographically guided AVF angioplasty. Conclusions: AVF-PTA can be performed safely and effectively guided by Doppler ultrasound, which simplifies the logistics required for its performance, although we still need to improve the capacity for early verification of the result with this imaging technique.

The study examined the socio-demographic factors affecting access to and utilization of social welfare services in Yenagoa Local Government Area of Bayelsa State, Nigeria. Quantitative and qualitative approaches were adopted to select 570 respondents from the study area. Probability and non-probability sampling techniques were adopted in the selection of communities, and respondents. The quantitative data were analyzed using frequency distribution tables and percentages, while chi-square statistic was used to determine the relationship between socio-demographic variables and access to and utilization of social welfare services. The qualitative data were analyzed in themes as a complement to the quantitative data. This study reveals that although all the respondents reported knowing available social welfare services, 44.3% reported not having access to existing social services due to factors connected to serendipity variables, such as terrain condition, ethnicity and knowing someone in government. Therefore, the study recommends that the government and other stakeholders should push for the massive delivery of much-needed social welfare services to address the issue of welfare service deficit across the nation, irrespective of the ethnic group and whether the community is connected to the government of the day or not, primarily in rural areas.

Surface-enhanced Raman scattering (SERS) spectrum has the characteristics of fast-detection, high-sensitivity and low-requirements for sample pretreatment. It plays a more and more important role in the detection of organic pollutants. In this study, MIL-101 and Au nanoparticles were prepared by hydrothermal method and aqueous solution reduction method respectively, and MIL-101/Au composite nanoparticles were prepared by electrostatic interaction. The SERS properties of the composite substrate were optimized by adjusting the size of Au nanoparticles and the surface distribution density of MIL-101 nanoparticles. The detection limit of Rhodamine 6G (R6G) for the composite substrate with the optimal ratio was investigated, which was as low as 10^–11 M. It is proved that MIL-101/Au composite nanoparticles have high sensitivity to probe molecules. When they are applied to the detection of persistent organic pollutants, the detection limit for fluoranthene can reach 10^–9 M and for 3,3’,4,4’-tetrachlorobiphenyl (PCB-77) can reach 10^–5 M.

The purpose of this article is to determine the equitability of airport and university allocations throughout Ethiopian regional states based on the number of airports and institutions per 1 million people. According to the sample, the majority of respondents believed that university allocation in Ethiopia is equitable. In contrast, the majority of respondents who were asked about airports stated that there is an uneven distribution of airports across Ethiopia’s regional states. Hence, both interviewees and focus group discussants stated that there is a lack of equitable distribution of universities and airports across Ethiopia’s regional states. This paper contributes a lesson on how to create a comprehensive set of determining factors for equitable infrastructure allocation. It also provides a methodological improvement for assessing infrastructure equity and other broader implications across Ethiopian regional states.

Salicylaldehyde imine transition metal catalyst is a kind of olefin polymerization catalyst that is widely used in the coordination of salicylaldehyde imine ligand and pre-transition metal. Salicylaldehyde imine ligands have the characteristic of easily inserting different substituents via organic synthesis. Therefore, the regulation of the polymerization activity, polymerization product, and product distribution can be achieved by changing the steric hindrance effect, the electronic effect, and the number of metal active sites near the catalytic active center. The development status of the transition metal catalyst of salicylaldehyde imide was summarized in this paper. The influence of the ligand structure of the salicylaldehyde imide transition metal catalyst on the catalytic performance, which involved the high selectivity of ethylene trimerization, ethylene/α-olefin, polar monomer copolymerization, ethylene polymerization production, ultra-high molecular weight polyethylene, and many other areas of olefin polymerization, was elaborated, providing references for further study and industrial applications of this catalyst.

New telechelic polymers functionalized with terminal ethyl xanthate or vinyl groups were synthesized via cationic ring-opening polymerization (CROP). The polymerization of 2-ethyl-2-oxazoline (Etoxa) and 2-methoxycarbonylethyl-2-oxazoline (Esteroxa) was initiated by 1,4-trans-dibromobutene in acetonitrile at 78 ℃, with termination using either potassium ethyl xanthate or 4-vinylbenzyl-piperazine. Structural characterization by ¹H and ¹³C NMR and FTIR spectroscopy confirmed the telechelic architecture. ¹H NMR analysis revealed degrees of polymerization (DP) of 24–29 for ethyl xanthate-terminated polymers and 22–23 for vinyl-terminated polymers, consistent with theoretical values. The molar compositions of Etoxa and Esteroxa in all telechelic polymers matched the initial monomer feed ratios. End-group functionalization efficiency was quantified as follows: Ethyl xanthate-terminated polymers: 64%–82%, and vinyl-terminated polymers: 69% and 98% (for respective batches).