Availability of essential medicines, progress and regional distribution in China: a systematic review and meta-analysis

BackgroundEssential medicines are the backbone of healthcare and meet the priority healthcare needs of the population. However, approximately one-third of the global population does not have access to essential medicines. Although China formulated essential medicine policies in 2009, the progress of availability of essential medicines and regional variations remains unknown. Therefore, this study was conducted to evaluate the availability of essential medicines, their progress, and regional distribution in China in the last decade.MethodsWe searched eight databases from their inception to February 2022, relevant websites, and reference lists of included studies. Two reviewers selected studies, extracted data, and evaluated the risk of bias independently. Meta-analyses were performed to quantify the availability of essential medicines, their progress, and regional distribution.ResultsOverall 36 cross-sectional studies conducted from 2009 to 2019 were included, with regional data for 14 provinces. The availability of essential medicines in 2015–2019 [28.1%, 95% confidence interval (CI): 26.4–29.9%] was similar to that in 2009–2014 (29.4%, 95% CI: 27.5–31.3%); lower in the Western region (19.8%, 95% CI: 18.1–21.5%) than Eastern (33.8%, 95% CI: 31.6–36.1%) and Central region (34.5%, 95% CI: 30.6–38.5%); very low for 8 Anatomical Therapeutic Chemical (ATC) categories (57.1%), and low for 5 categories (35.7%) among all ATC groups.ConclusionThe availability of essential medicines in China is low compared with the World Health Organization goal, has not changed much in the last decade, is unequal across regions, and lacks data for half of provinces. For policy-making, the monitoring system of the availability of essential medicines is to be strengthened to enable long-term surveillance, especially in provinces where the data has been missing. Meanwhile, Joint efforts from all stakeholders are warranted to improve the availability of essential medicines in China toward the universal health coverage target.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=315267, identifier: PROSPERO CRD42022315267

Formation mechanism of 0.4-nm single-walled carbon nanotubes in A1PO(4)-5 crystals by low-temperature hydrocracking

The carbonization mechanism of tripropylamine (TPA) in low-temperature hydrocracking was studied with the aim of increasing the quality and filling density of single-walled carbon nanotubes (SWCNTs) produced in the channels of AlPO4-5 crystals. The conversion process of TPA was investigated using a combination of Fourier transform infrared spectroscopy, mass spectrometry, C-13 nuclear magnetic resonance spectroscopy, thermogravimetric analysis and micro-Raman spectroscopy at various hydro cracking temperatures. During the hydrocracking process, hydrogen participated in the cracking reaction of TPA and decreased the required activation energy. The protonated TPA converted into neutral TPA at 210 degrees C. When the hydrocracking temperature exceeded 260 degrees C, dipropylamine, n-propylamine, propylene, propane, ethane and methane were produced. The hydrocracking rate of TPA increased with increasing hydrocracking temperature. A small amount of aromatic compounds was also detected in the A1PO(4)-5 crystals hydrocracked at 280-350 degrees C; this amount decreased with increasing hydrocracking temperature. The content of residual TPA and amorphous carbon compounds in the AlPO4-5 crystals also decreased with increasing hydrocracking temperature. TPA decomposed completely after hydrocracking for 10 h at 350 degrees C. SWCNTs with a diameter of 0.4 nm were synthesized at 280-350 degrees C, and the filling density of SWCNTs increased with increasing hydrocracking temperature. (c) 2017 Elsevier Ltd. All rights reserved

Fabrication of single-walled carbon nanotubes in the channels of CoAPO-5 membrane by low-temperature hydrocracking

The defect-free CoAPO-5 membrane was fabricated on the porous alpha-Al(2)O(3 )substrate by using in-situ crystallization, and the prepared CoAPO-5 membrane was used as the template for the preparation of single-walled carbon nanotubes (SWCNTs) inside the liner channels (0.73 nm in diameter) by low-temperature hydrocracking, utilizing the organic precursor (tripmpylamine) as the carbon source. The results of X-ray diffraction and scanning electron microscopy indicated that the synthesized membrane covered tightly on the alpha-Al2O3 substrate was 50 mu m in thickness, which was composed of well-intergrown and randomly oriented CoAPO-5 molecular sieves. According to the characterization using high-resolution transmission electron microscopy, polarized Raman scattering and thermal-gravimetric analysis, 0.4 nm SWCNTs were synthesized inside the zeolitic channels of the CoAPO-5 membrane, and 45.47% tripropylamine were successfully converted into SWCNTs after hydrocracking for 12 hat 350 degrees C. On the basis of N(2 )adsorption/desorption isotherms for the CoAPO-5 molecular sieves and SWCNTs/CoAPO-5 composite material, it can be concluded that the fraction of channels not containing SWCNTs in the resulting SWCNTs/CoAPO-5 composite membrane is small. The results of single-component pervaporation demonstrate that the inter-crystal defects in the as-synthesized SWCNTs/CoAPO-5 composite membrane are negligible

Preparation Process Exploration of b-Oriented MFI Zeolite Films

Due to its unique nanometer-sized straight channel structure, the b-oriented MFI zeolite films have great potential in separation membranes, membrane reactors, and chemical sensors. Thus, there has been growing interest in the preparation of zeolite films with preferred b-orientation. Recent advances in the preparation process of b-oriented MFI zeolite films are reviewed in this paper. The methods of in situ hydrothermal synthesis and secondary growth are further described in detail. In particular, it is summarized and evaluated for the very recent research results in the modification of the substrate surface, the preparation of b-oriented MFI zeolite arrays, and the regulation of hydrothermal synthesis conditions. Based on the extensive discussion of the merits and demerits of various preparation methods, the trends in the manufacture of b-oriented zeolite films are prospected

Reactors for Hydrogen Production by Bio-Ethanol Reforming

Bio-ethanol reforming is a type of promising technology for hydrogen production, which is focused on current low-carbon energy research. The key of ethanol reforming is to develop novel reforming catalysts with high activity and high selectivity at low temperature, and new efficient catalytic reactors. The effects of reactors on ethanol reforming process are focused in this paper, and ethanol reforming reactors at home and abroad are reviewed, such as fixed-bed reactors, microchannel reactors and membrane reactors. Based on the extensive discussion of the advantages and weaknesses of various catalytic reactors, the trends in the manufacture and application of bio-ethanol reforming reactors are also prospected. In our opinions, the following aspects need to be studied systematically; (1) strengthening basic theoretical researches, especially the reaction mechanisms of bio-ethanol reforming and the principles of mass/heat transfer, (2) developing novel low-temperature reforming catalysts with high activity, high stability, and low cost, (3) designing highly integrated catalytic reactors for bio-ethanol reforming

Catalytic activities of K-modified zeolite ZSM-5 supported rhodium catalysts in low-temperature steam reforming of bioethanol

Recently, zeolite materials have attracted attention as efficient catalysts for low-temperature steam reforming of bioethanol (SRE). However, cost-effective zeolite ZSM-5 materials, one of the most popular industrial reforming catalysts, were rarely reported for SRE. In this study, low-load rhodium (Rh) catalysts are prepared using commercial high-silica zeolite ZSM-5 as the supports. The commercial zeolite ZSM-5 has strong acidic sites that lead to fairly extensive dehydration of bioethanol. To generate basic sites and mesoporous structure, zeolite supports are modified by K ion exchange and alkali treatment. The effect of the physicochemical properties of the modified supports on low-temperature SRE reaction is investigated by SEM, TEM, XRD, XRF, TPD, NMR and N-2 adsorption. The results indicate that strong acidic sites in zeolite ZSM-5 can be effectively neutralized by K ion exchange, while basic sites in zeolite ZSM-5 are noticeably altered only by alkali treatment. The hydrogen selectivity can be significantly promoted by the alkalinity of the zeolite KZSM-5, however, only the moderate alkali-treated Rh/S2 catalyst retains its high activity during reaction. Our results appear to demonstrate the positive effect of the special zeolitic structure of the Rh/52 catalyst with uniform mesopores, which can improve the Rh dispersion and avoid its sintering. Moreover, there seem to be a unique synergy between the Rh active component and the alkali-treated zeolite support, which might result in the lowest CO selectivity at 300-400 degrees C. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved