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Zhao LM, Meng QY, Fan XB, Ye C, Li XB, Chen B, Ramamurthy V, Tung CH, Wu LZ. Photocatalysis with Quantum Dots and Visible Light: Selective and Efficient Oxidation of Alcohols to Carbonyl Compounds through a Radical Relay Process in Water. Angew Chem Int Ed Engl 2017; 56:3020-3024. [DOI: 10.1002/anie.201700243] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Indexed: 12/19/2022]
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Zhao LM, Meng QY, Fan XB, Ye C, Li XB, Chen B, Ramamurthy V, Tung CH, Wu LZ. Photocatalysis with Quantum Dots and Visible Light: Selective and Efficient Oxidation of Alcohols to Carbonyl Compounds through a Radical Relay Process in Water. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700243] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Zhong JJ, Meng QY, Chen B, Tung CH, Wu LZ. Visible Light Induced Cross-Coupling Hydrogen Evolution Reactions. ACTA CHIMICA SINICA 2017. [DOI: 10.6023/a16090491] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Wu CJ, Cao WX, Lei T, Li ZH, Meng QY, Yang XL, Chen B, Ramamurthy V, Tung CH, Wu LZ. A sustainable synthesis of 2-aryl-3-carboxylate indolines from N-aryl enamines under visible light irradiation. Chem Commun (Camb) 2017; 53:8320-8323. [DOI: 10.1039/c7cc04358a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
With visible light irradiation of a catalytic amount of Ir(ppy)3 at room temperature, a number of N-aryl enamines were transformed into their corresponding indoline products in good to excellent yields without requiring any extra additives.
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Li ZJ, Zhan F, Xiao H, Zhang X, Kong QY, Fan XB, Liu WQ, Huang MY, Huang C, Gao YJ, Li XB, Meng QY, Feng K, Chen B, Tung CH, Zhao HF, Tao Y, Wu LZ. Tracking Co(I) Intermediate in Operando in Photocatalytic Hydrogen Evolution by X-ray Transient Absorption Spectroscopy and DFT Calculation. J Phys Chem Lett 2016; 7:5253-5258. [PMID: 27973864 DOI: 10.1021/acs.jpclett.6b02479] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
X-ray transient absorption spectroscopy (XTA) and optical transient spectroscopy (OTA) were used to probe the Co(I) intermediate generated in situ from an aqueous photocatalytic hydrogen evolution system, with [RuII(bpy)3]Cl2·6H2O as the photosensitizer, ascorbic acid/ascorbate as the electron donor, and the Co-polypyridyl complex ([CoII(DPA-Bpy)Cl]Cl) as the precatalyst. Upon exposure to light, the XTA measured at Co K-edge visualizes the grow and decay of the Co(I) intermediate, and reveals its Co-N bond contraction of 0.09 ± 0.03 Å. Density functional theory (DFT) calculations support the bond contraction and illustrate that the metal-to-ligand π back-bonding greatly stabilizes the penta-coordinated Co(I) intermediate, which provides easy photon access. To the best of our knowledge, this is the first example of capturing the penta-coordinated Co(I) intermediate in operando with bond contraction by XTA, thereby providing new insights for fundamental understanding of structure-function relationship of cobalt-based molecular catalysts.
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Zheng YW, Chen B, Ye P, Feng K, Wang W, Meng QY, Wu LZ, Tung CH. Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C–H Amination and Hydroxylation. J Am Chem Soc 2016; 138:10080-3. [DOI: 10.1021/jacs.6b05498] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Fan XW, Lei T, Zhou C, Meng QY, Chen B, Tung CH, Wu LZ. Radical Addition of Hydrazones by α-Bromo Ketones To Prepare 1,3,5-Trisubstituted Pyrazoles via Visible Light Catalysis. J Org Chem 2016; 81:7127-33. [PMID: 27362866 DOI: 10.1021/acs.joc.6b00992] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel efficient tandem reaction of hydrazones and α-bromo ketones is reported for the preparation of 1,3,5-trisubstituted pyrazoles by visible light catalysis. In this system, the monosubstituted hydrazones show wonderful reaction activity with alkyl radicals, generated from α-bromo ketones. A radical addition followed by intramolecular cyclization affords the important pyrazole skeleton in good to excellent yields. This efficient strategy under mild conditions with wide group tolerance provides a potential approach to the 1,3,5-trisubstituted pyrazoles.
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Wu CJ, Meng QY, Lei T, Zhong JJ, Liu WQ, Zhao LM, Li ZJ, Chen B, Tung CH, Wu LZ. An Oxidant-Free Strategy for Indole Synthesis via Intramolecular C–C Bond Construction under Visible Light Irradiation: Cross-Coupling Hydrogen Evolution Reaction. ACS Catal 2016. [DOI: 10.1021/acscatal.6b00917] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Qiao SP, Zhao YF, Li CF, Yin YB, Meng QY, Lin FH, Liu Y, Hou XL, Guo K, Chen XB, Tian WM. An alginate-based platform for cancer stem cell research. Acta Biomater 2016; 37:83-92. [PMID: 27109764 DOI: 10.1016/j.actbio.2016.04.032] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 04/14/2016] [Accepted: 04/18/2016] [Indexed: 12/14/2022]
Abstract
UNLABELLED As the primary determinants of the clinical behaviors of human cancers, the discovery of cancer stem cells (CSCs) represents an ideal target for novel anti-cancer therapies (Kievit et al., 2014). Notably, CSCs are difficult to propagate in vitro, which severely restricts the study of CSC biology and the development of therapeutic agents. Emerging evidence indicates that CSCs rely on a niche that controls their differentiation and proliferation, as is the case with normal stem cells (NSCs). Replicating the in vivo CSC microenvironment in vitro using three-dimensional (3D) porous scaffolds can provide means to effectively generate CSCs, thus enabling the discovery of CSC biology. This paper presents our study on a novel alginate-based platform for mimicking the CSC niche to promote CSC proliferation and enrichment. In this study, we used a versatile mouse 4T1 breast cancer model to independently evaluate the matrix parameters of a CSC niche - including the material's mechanical properties, cytokine immobilization, and the composition of the extracellular matrix's (ECM's) molecular impact - on CSC proliferation and enrichment. On this basis, the optimal stiffness and concentration of hyaluronic acid (HA), as well as epidermal growth factor and basic fibroblast growth factor immobilization, were identified to establish the platform for mimicking the 4T1 breast CSCs (4T1 CSCs) niche. The 4T1 CSCs obtained from the platform show increased expression of the genes involved in breast CSC and NSC, as compared to general 2D or 3D culture, and 4T1 CSCs were also demonstrated to have the ability to quickly form a subcutaneous tumor in homologous Balb/c mice in vivo. In addition, the platform can be adjusted according to different parameters for CSC screening. Our results indicate that our platform offers a simple and efficient means to isolate and enrich CSCs in vitro, which can help researchers better understand CSC biology and thus develop more effective therapeutic agents to treat cancer. STATEMENT OF SIGNIFICANCE As the primary determinants of the clinical behaviors of human cancers, the discovery of cancer stem cells (CSCs) represents an ideal target for novel anti-cancer therapies. However, CSCs are difficult to propagate in vitro, which severely restricts the study of CSC biology and the development of therapeutic agents. Emerging evidence indicates that CSCs rely on a niche that controls their differentiation and proliferation, as is the case with normal stem cells (NSCs). Replicating the in vivo CSC microenvironment in vitro using three-dimensional (3D) porous scaffolds can provide means to effectively generate CSCs, thus enabling the discovery of CSC biology. In our study, a novel alginate-based platform were developed for mimicking the CSC niche to promote CSC proliferation and enrichment.
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Lei T, Liu WQ, Li J, Huang MY, Yang B, Meng QY, Chen B, Tung CH, Wu LZ. Visible Light Initiated Hantzsch Synthesis of 2,5-Diaryl-Substituted Pyrroles at Ambient Conditions. Org Lett 2016; 18:2479-82. [DOI: 10.1021/acs.orglett.6b01059] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Wang J, Feng K, Xie N, Li ZJ, Meng QY, Chen B, Tung CH, Wu LZ. Solution-processable graphenes by covalent functionalization of graphene oxide with polymeric monoamines. Sci China Chem 2016. [DOI: 10.1007/s11426-015-5523-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Ye P, Wang DH, Chen B, Meng QY, Tung CH, Wu LZ. Visible light catalyzed aromatization of 1,3,5-triaryl-2-pyrazolines by platinum(II) polypyridyl complex under oxidant-free condition. Sci China Chem 2016. [DOI: 10.1007/s11426-016-5554-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Xiang M, Meng QY, Gao XW, Lei T, Chen B, Tung CH, Wu LZ. Reactivity and mechanistic insight into the cross coupling reaction between isochromans and β-keto esters through C–H bond activation under visible light irradiation. Org Chem Front 2016. [DOI: 10.1039/c5qo00412h] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The formation of a C(sp3)–C(sp3) bond next to an oxygen atom from two different C–H bonds is realized by oxidative photocatalysis.
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Zhong JJ, Liu Q, Wu CJ, Meng QY, Gao XW, Li ZJ, Chen B, Tung CH, Wu LZ. Combining visible light catalysis and transfer hydrogenation for in situ efficient and selective semihydrogenation of alkynes under ambient conditions. Chem Commun (Camb) 2016; 52:1800-3. [DOI: 10.1039/c5cc08697c] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
By combining visible light catalysis and transfer hydrogenation, we are able to convert a series of alkynes to their corresponding alkenes in high chemical yields.
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Xiang M, Meng QY, Li JX, Zheng YW, Ye C, Li ZJ, Chen B, Tung CH, Wu LZ. Activation of CH Bonds through Oxidant-Free Photoredox Catalysis: Cross-Coupling Hydrogen-Evolution Transformation of Isochromans and β-Keto Esters. Chemistry 2015; 21:18080-4. [DOI: 10.1002/chem.201503361] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Indexed: 12/21/2022]
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Gao XW, Meng QY, Li JX, Zhong JJ, Lei T, Li XB, Tung CH, Wu LZ. Visible Light Catalysis Assisted Site-Specific Functionalization of Amino Acid Derivatives by C–H Bond Activation without Oxidant: Cross-Coupling Hydrogen Evolution Reaction. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00093] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wu CJ, Zhong JJ, Meng QY, Lei T, Gao XW, Tung CH, Wu LZ. Cobalt-Catalyzed Cross-Dehydrogenative Coupling Reaction in Water by Visible Light. Org Lett 2015; 17:884-7. [DOI: 10.1021/ol503744a] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Wang XZ, Meng QY, Zhong JJ, Gao XW, Lei T, Zhao LM, Li ZJ, Chen B, Tung CH, Wu LZ. The singlet excited state of BODIPY promoted aerobic cross-dehydrogenative-coupling reactions under visible light. Chem Commun (Camb) 2015; 51:11256-9. [DOI: 10.1039/c5cc03421c] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We disclose for the first time that the singlet excited state (1PS*) of BODIPY rather than triplet excited state (3PS*) can drive C–H bond activation to form C–C and C–P bonds smoothly upon irradiation by visible light.
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Tao CS, Qiu ZY, Meng QY, Wu JJ, Liu F, Wang CM, Cui FZ. Mineralized Collagen Incorporated Polymethyl Methacrylate Bone Cement for Percutaneous Vertebroplasty and Percutaneous Kyphoplasty. J BIOMATER TISS ENG 2014. [DOI: 10.1166/jbt.2014.1250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Meng QY, Lei T, Zhao LM, Wu CJ, Zhong JJ, Gao XW, Tung CH, Wu LZ. A Unique 1,2-Acyl Migration for the Construction of Quaternary Carbon by Visible Light Irradiation of Platinum(II) Polypyridyl Complex and Molecular Oxygen. Org Lett 2014; 16:5968-71. [DOI: 10.1021/ol502995h] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Zhong JJ, Wu CJ, Meng QY, Gao XW, Lei T, Tung CH, Wu LZ. A Cascade Cross-Coupling andin SituHydrogenation Reaction by Visible Light Catalysis. Adv Synth Catal 2014. [DOI: 10.1002/adsc.201400588] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Chen Z, Kang L, Meng QY, Liu H, Wang Z, Guo Z, Cui FZ. Degradability of injectable calcium sulfate/mineralized collagen-based bone repair material and its effect on bone tissue regeneration. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 45:94-102. [PMID: 25491806 DOI: 10.1016/j.msec.2014.08.060] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/31/2014] [Accepted: 08/29/2014] [Indexed: 11/17/2022]
Abstract
The nHAC/CSH composite is an injectable bone repair material with controllable injectability and self-setting properties prepared by introducing calcium sulfate hemihydrate (CSH) into mineralized collagen (nHAC). When mixed with water, the nHAC/CSH composites can be transformed into mineralized collagen/calcium sulfate dihydrate (nHAC/CSD) composites. The nHAC/CSD composites have good biocompatibility and osteogenic capability. Considering that the degradation behavior of bone repair material is another important factor for its clinical applications, the degradability of nHAC/CSD composites was studied. The results showed that the degradation ratio of the nHAC/CSD composites with lower nHAC content increased with the L/S ratio increase of injectable materials, but the variety of L/S ratio had no significant effect on the degradation ratio of the nHAC/CSD composites with higher nHAC content. Increasing nHAC content in the composites could slow down the degradation of nHAC/CSD composite. Setting accelerator had no significant effect on the degradability of nHAC/CSD composites. In vivo histological analysis suggests that the degradation rate of materials can match the growth rate of new mandibular bone tissues in the implanted site of rabbit. The regulable degradability of materials resulting from the special prescriptions of injectable nHAC/CSH composites will further improve the workability of nHAC/CSD composites.
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Wang J, Feng K, Zhang HH, Chen B, Li ZJ, Meng QY, Zhang LP, Tung CH, Wu LZ. Enhanced photocatalytic hydrogen evolution by combining water soluble graphene with cobalt salts. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2014; 5:1167-1174. [PMID: 25161850 PMCID: PMC4142871 DOI: 10.3762/bjnano.5.128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 07/02/2014] [Indexed: 06/03/2023]
Abstract
There is tremendous effort put in the pursuit for cheap and efficient catalysts for photocatalytic hydrogen evolution systems. Herein, we report an active catalyst that uses the earth-abundant element cobalt and water-dispersible sulfonated graphene. The photocatalytic hydrogen evolution activity of the catalyst was tested by using triethanolamine (TEOA) as electron donor and eosin Y (EY) as the photosensitizer under LED irradiation at 525 nm. Hydrogen was produced constantly even after 20 h, and the turnover number (TON) reached 148 (H2/Co) in 4 h with respect to the initial concentration of the added cobalt salts was shown to be 5.6 times larger than that without graphene.
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Li ZJ, Fan XB, Li XB, Li JX, Ye C, Wang JJ, Yu S, Li CB, Gao YJ, Meng QY, Tung CH, Wu LZ. Visible light catalysis-assisted assembly of Ni(h)-QD hollow nanospheres in situ via hydrogen bubbles. J Am Chem Soc 2014; 136:8261-8. [PMID: 24835886 DOI: 10.1021/ja5047236] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hollow spheres are one of the most promising micro-/nanostructures because of their unique performance in diverse applications. Templates, surfactants, and structure-directing agents are often used to control the sizes and morphologies of hollow spheres. In this Article, we describe a simple method based on visible light catalysis for preparing hollow nanospheres from CdE (E = Te, Se, and S) quantum dots (QDs) and nickel (Ni(2+)) salts in aqueous media. In contrast to the well-developed traditional approaches, the hollow nanospheres of QDs are formed in situ by the photogeneration of hydrogen (H2) gas bubbles at room temperature. Each component, that is, the QDs, metal ions, ascorbic acid (H2A), and visible light, is essential for the formation of hollow nanospheres. The quality of the hollow nanospheres depends on the pH, metal ions, and wavelength and intensity of visible light used. Of the various metal ions investigated, including Cu(+), Cu(2+), Fe(2+), Fe(3+), Ni(2+), Mn(2+), RuCl5(2-), Ag(+), and PtCl4(2-), Ni(2+) ions showed the best ability to generate H2 and hollow-structured nanospheres under visible light irradiation. The average diameter and shell thickness of the nanospheres ranged from 10 to 20 nm and from 3 to 6 nm, respectively, which are values rarely reported in the literature. Studies using high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), inductively coupled plasma-mass spectroscopy (ICP-AES), and steady-state and time-resolved spectroscopy revealed the chemical nature of the hollow nanospheres. Additionally, the hollow-structured nanospheres exhibit excellent photocatalytic activity and stability for the generation of H2 with a rate constant of 21 μmol h(-1) mg(-1) and a turnover number (TON) of 137,500 or 30,250 for CdTe QDs or nickel, respectively, under visible light irradiation for 42 h.
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Li SP, Zheng ZY, Meng QY, Yuan CH. Barriers to tuberculosis care for drug users in two provinces of China: a qualitative study. Int J Tuberc Lung Dis 2014; 17:1358-63. [PMID: 24025390 DOI: 10.5588/ijtld.12.0784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
SETTING Two compulsory drug rehabilitation centres in Yunnan and Sichuan Provinces, Southwest China. OBJECTIVE To understand barriers to tuberculosis (TB) care among drug users in China, and to provide policy recommendations to improve TB control in the drug-using population. DESIGN A qualitative study was designed using in-depth interviews with 147 drug users with TB and 12 key informants. Drug users were purposively selected from two compulsory drug rehabilitation centres and key informants from national and provincial justice administration, local TB control dispensaries and compulsory drug rehabilitation centres. RESULTS Lack of health awareness and knowledge was reported as one barrier to TB care among drug users. The majority of the respondents lacked social support and perceived fear and stigma when seeking TB care. More than half of the respondents who had discontinued their anti-tuberculosis treatment reported that this was due to drug use. Limited provision of TB care in the compulsory drug rehabilitation centres and local TB control dispensaries was also reported as one of the barriers to TB care among drug users. CONCLUSIONS These findings suggest that barriers to TB care for drug users are associated not only with the drug users themselves, but also with the providers and societal factors. Health professionals and policy makers should be aware of these barriers in China.
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