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Sun RC, Lyu KY, Feng GW, Xu QY, Lan YJ. [The mediating role of worker-occupation fit between occupational stress and anxiety symptoms in medical staff]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2022; 40:495-500. [PMID: 35915938 DOI: 10.3760/cma.j.cn121094-20210425-00231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Objective: To analyze the mediating effect of work-occupation fit between occupational stress and anxiety symptoms in medical staff. Methods: Convenience sampling method was adopted to select participants of one general hospital and three specialized hospitals as respondents for a questionnaire survey in Henan Province from October 2020 to January 2021. A total of 2050 medical staff were investigated, and 1988 valid questionnaires were collected, and the effective rate of the questionnaire was 97.0% (1988/2050) . The "Depression-Anxiety-Stress Scale" and "Worker-Occupation Fit Inventory" were used to evaluate the occupational stress, anxiety symptoms and worker-occupation fit level of medical staff, and the mediation effect of work-occupation fit on the relationship between occupational stress and anxiety symptoms was analyzed using a mediating effect model. Results: The average age of the 1988 medical staff was (32.7±7.8) years old, the positive detection rates of occupational stress and anxiety symptoms were 42.5% (845/1988) and 56.7% (1127/1988) , respectively. Anxiety symptoms of medical staff were positively correlated with occupational stress, negatively correlated with worker-occupation fit (r=0.831, -0.364, P<0.001) , work-occupation fit was negatively correlated with occupational stress (r=-0.259, P<0.001) . The results of the mediation effect analysis showed that occupational stress had a direct effect on anxiety symptoms (β=0.677, BCa 95%CI: 0.648-0.707) , and worker-occupation fit (β=0.047, BCa 95%CI: 0.039-0.056) , characteristic fit (β=0.089, BCa 95%CI: 0.074-0.104) , need-supply fit (β=0.075, BCa 95%CI: 0.062-0.089) , and ability-demand fit (β=0.035, BCa 95%CI: 0.026-0.044) mediated the association between occupational stress and anxiety symptoms in medical staff, with the mediating effect as a percentage of 6.5%, 12.3%, 10.3%, and 4.8%, respectively. Conclusion: Worker-occupation fit has a mediating effect between occupational stress and anxiety symptoms in medical staff, but mainly direct effect.
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Affiliation(s)
- R C Sun
- Department of Preventive Medicine, School of Public Health, Chengdu Medical College, Chengdu 610500, China
| | - K Y Lyu
- Department of Occupational and Environmental Health, West China School of Public Health/West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - G W Feng
- Department of Occupational and Environmental Health, West China School of Public Health/West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Q Y Xu
- Department of Occupational and Environmental Health, West China School of Public Health/West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Y J Lan
- Department of Occupational and Environmental Health, West China School of Public Health/West China Fourth Hospital, Sichuan University, Chengdu 610041, China
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Feng GW, Sun RC, Xu QY, Lan YJ. [Literature analysis of hot topics on occupational noise-induced hearing loss]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2022; 40:279-282. [PMID: 35545595 DOI: 10.3760/cma.j.cn121094-20210329-00174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Objective: To analyze the literature of related research reports on occupational hearing loss (ONIHL) , study the characteristics of the subject and determine the research hotspots. Methods: In December 2020, PubMed database was searched by bibliometrics for ONIHL published in PubMed database from January 1971 to December 2020. Bicomb 2.03 software was used to extract the subject. The publication year, publication country, source magazine and subject words were summarized and analyzed. Results: A total of 1 473 papers were included in this study, and the number of papers was 66 from 1971 to 1980, and 628 from 2011 to 2020, an increase of nearly 10 times. The top three countries were the United States, China and Germany, with 31.5% (464/1473) , 11.5% (171/1473) and 6.2% (91/1473) ; The cross-sectional study was the most applied type; The top five words for 2011-2020: Mental Illness, polymorphism, cardiovascular disease, high frequency hearing impairment and standards and regulations. Conclusion: Susceptibility Genes, Psychological Disorders, Cardiovascular Diseases and Risk Assessment are hot areas in ONIHL at present. Researchers should focus on major fields and grasp future trends as a whole.
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Affiliation(s)
- G W Feng
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - R C Sun
- Department of Preventive Medicine, School of Public Health, Chengdu Medical College, Chengdu 610050, China
| | - Q Y Xu
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Y J Lan
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
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Krispin E, Mustafa HJ, Sun RC, Donepudi R, Espinoza J, Nassr AA, Belfort MA, Sanz Cortes M, Mostafaei S, Harman C, Turan O, Shamshirsaz AA. Iatrogenic chorioamniotic separation and septostomy following fetoscopic laser photocoagulation for twin-twin transfusion syndrome. Ultrasound Obstet Gynecol 2022; 59:506-512. [PMID: 34182599 DOI: 10.1002/uog.23723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/04/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
OBJECTIVE To compare the perinatal outcomes of pregnancies complicated by chorioamniotic separation (CAS) vs septostomy following fetoscopic laser photocoagulation (FLP) for twin-twin transfusion syndrome (TTTS). METHODS This was a retrospective cohort analysis of monochorionic diamniotic twin pregnancies with TTTS that underwent FLP at one of two university-affiliated tertiary medical centers between January 2012 and December 2020. CAS and septostomy were diagnosed either during the procedure or by ultrasonography within 24-48 h after FLP. Data on procedure and postprocedure parameters, pregnancy outcomes and survival were collected from the patients' electronic medical records. Pregnancies were stratified according to the presence of CAS, septostomy or neither. Patients diagnosed with both CAS and septostomy were analyzed separately. RESULTS Of the 522 women included in the cohort, 38 (7.3%) were diagnosed with CAS, 68 (13.0%) with septostomy and 23 (4.4%) with both CAS and septostomy. The remaining 393 (75.3%) women comprised the control group. Groups did not differ in demographic characteristics. The septostomy group had a lower rate of selective fetal growth restriction than did the CAS and control groups (24.2% vs 36.8% vs 42.7%, respectively; P = 0.017). Moreover, intertwin size discordance was lower in the septostomy group (15.1% vs 23.4% in the CAS group and 25.5% in the control group; P = 0.001). Median gestational age at FLP was significantly lower in the CAS group (19.3 weeks vs 20.4 weeks in controls and 20.9 weeks in the septostomy group; P = 0.049). The rate of delivery prior to 34 weeks was significantly higher in the CAS group (89.2%), followed by the septostomy group (80.9%), compared with the control group (69.0%) (P = 0.006). A secondary analysis demonstrated that patients with both CAS and septostomy presented the highest rates of delivery prior to 34 weeks (100%) and 32 weeks (68.2%). CONCLUSIONS CAS and septostomy following laser surgery for TTTS are independently associated with higher rates of preterm delivery. The presence of these two findings in the same patient enhances the risk of prematurity. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.
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Affiliation(s)
- E Krispin
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA
| | - H J Mustafa
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - R C Sun
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA
| | - R Donepudi
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA
| | - J Espinoza
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA
| | - A A Nassr
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA
| | - M A Belfort
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA
| | - M Sanz Cortes
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA
| | - S Mostafaei
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - C Harman
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - O Turan
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - A A Shamshirsaz
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA
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Hessami K, Nassr AA, Sananès N, Castillo J, Castillo HA, Sanz Cortes M, Espinoza J, Donepudi RV, Sun RC, Krispin E, Belfort MA, Shamshirsaz AA. Perinatal risk factors of neurodevelopmental impairment after fetoscopic laser photocoagulation for twin-twin transfusion syndrome: systematic review and meta-analysis. Ultrasound Obstet Gynecol 2021; 58:658-668. [PMID: 34097320 DOI: 10.1002/uog.23706] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/19/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
OBJECTIVE Monochorionic twins with twin-twin transfusion syndrome (TTTS) treated with fetoscopic laser photocoagulation (FLP) are at increased risk of neurodevelopmental impairment (NDI). This meta-analysis aimed to identify the prevalence of and perinatal risk factors for NDI in TTTS survivors treated with FLP. METHODS We performed a search in PubMed, EMBASE, Scopus and Web of Science, from inception to 13 February 2021, for studies evaluating perinatal risk factors for NDI in children diagnosed prenatally with TTTS managed by FLP. Data on severity of TTTS at the time of diagnosis, defined according to the Quintero staging system, FLP-related complications and perinatal outcomes were compared between children with a history of TTTS treated with FLP with and those without NDI, which was defined as performance on a cognitive or developmental assessment tool ≥ 2 SD below the mean or a defined motor or sensory disability. A random-effects model was used to pool the mean differences or odds ratios (OR) with the corresponding 95% CIs. Heterogeneity was assessed using the I2 statistic. RESULTS Nine studies with a total of 1499 TTTS survivors were included. The overall incidence of NDI was 14.0% (95% CI, 9.0-18.0%). The occurrence of NDI in TTTS survivors was associated with later gestational age (GA) at FLP (mean difference, 0.94 weeks (95% CI, 0.50-1.38 weeks); P < 0.0001, I2 = 0%), earlier GA at delivery (mean difference, -1.44 weeks (95% CI, -2.28 to -0.61 weeks); P = 0.0007, I2 = 49%) and lower birth weight (mean difference, -343.26 g (95% CI, -470.59 to -215.92 g); P < 0.00001, I2 = 27%). Evaluation of different GA cut-offs showed that preterm birth before 32 weeks was associated with higher risk for NDI later in childhood (OR, 2.25 (95% CI, 1.02-4.94); P = 0.04, I2 = 35%). No statistically significant difference was found between cases with and those without NDI with respect to Quintero stage of TTTS, recipient or donor status, development of postlaser twin anemia-polycythemia sequence, recurrence of TTTS and incidence of small- for-gestational age or cotwin fetal demise. CONCLUSIONS TTTS survivors with later GA at the time of FLP, earlier GA at delivery and lower birth weight are at higher risk of developing NDI. No significant association was found between Quintero stage of TTTS and risk of NDI. Our findings may be helpful for parental counseling and highlight the need for future studies to understand better the risk factors for NDI in TTTS survivors. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.
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Affiliation(s)
- K Hessami
- Maternal-Fetal Medicine Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Obstetrics and Gynecology, Baylor College of Medicine & Texas Children's Fetal Center, Houston, TX, USA
| | - A A Nassr
- Department of Obstetrics and Gynecology, Baylor College of Medicine & Texas Children's Fetal Center, Houston, TX, USA
| | - N Sananès
- Department of Maternal-Fetal Medicine, Strasbourg University Hospital, Strasbourg, France
| | - J Castillo
- Department of Pediatrics, Baylor College of Medicine & Texas Children's Hospital, Houston, TX, USA
| | - H A Castillo
- Department of Pediatrics, Baylor College of Medicine & Texas Children's Hospital, Houston, TX, USA
| | - M Sanz Cortes
- Department of Obstetrics and Gynecology, Baylor College of Medicine & Texas Children's Fetal Center, Houston, TX, USA
| | - J Espinoza
- Department of Obstetrics and Gynecology, Baylor College of Medicine & Texas Children's Fetal Center, Houston, TX, USA
| | - R V Donepudi
- Department of Obstetrics and Gynecology, Baylor College of Medicine & Texas Children's Fetal Center, Houston, TX, USA
| | - R C Sun
- Doernbecher Children's Hospital, Oregon Health & Science University, Division of Pediatric Surgery, Portland, OR, USA
- Division of Pediatric Surgery, Baylor College of Medicine & Texas Children's Hospital, Houston, TX, USA
| | - E Krispin
- Department of Obstetrics and Gynecology, Baylor College of Medicine & Texas Children's Fetal Center, Houston, TX, USA
| | - M A Belfort
- Department of Obstetrics and Gynecology, Baylor College of Medicine & Texas Children's Fetal Center, Houston, TX, USA
| | - A A Shamshirsaz
- Department of Obstetrics and Gynecology, Baylor College of Medicine & Texas Children's Fetal Center, Houston, TX, USA
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Abstract
Objective: To explore the relationship between the worker-occupation fit and occupational stress in nurses. Methods: Convenience sampling method was used to collect 1 463 nurses from one general hospital and three specialized hospitals from July to October 2019. Depression-anxiety-stress scale (DASS-21) was used to assess the level of occupational stress. Pearson correlation and multivariate logistic regression model were used to analyze the relationship between the worker-occupation fit and occupational stress. Results: The average age of 1 463 nurses was (31.8±7.2) years, and 92.3% (n=1 350) of nurses were female. 47.2% (n=690) of nurses had occupational stress and the mean score of worker-occupation fit was (34.4±6.1). The worker-occupation fit and occupational stress had a significant negative correlation (r=-0.472, P<0.001). The moderate and high level of the worker-occupation fit, characteristic fit, need supply fit, and demand ability fit had protective effects on occupational stress based on the outcome of multivariate logistic regression model [OR (95%CI) were 0.40 (0.28-0.59), 0.16 (0.10-0.24); 0.32 (0.22-0.47), 0.18 (0.11-0.20); 0.33 (0.21-0.52), 0.18 (0.11-0.30); 0.59 (0.37-0.9), 0.54 (0.38-0.78), respectively]. Conclusion: The worker-occupation fit and different types of fit, including characteristic fit, need supply fit, and demand ability fit, could be associated with the occupational stress.
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Affiliation(s)
- R C Sun
- Ruican Sun Department of Preventive Medicine,School of Public Health,Chengdu Medical College,Chengdu 610500, China
| | - Y J Lan
- Yajia Lan Department of Occupational and Environmental Health,West China School of Public Health, Sichuan University, Chengdu 610041, China
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Wu YL, Hu LN, Zheng CD, Sun RC, Zhang SX, Yan Q, Li YX. [Expression of hypoxia-inducible factor 1α in gastric cancer and its clinical signficance]. Zhonghua Yi Xue Za Zhi 2016; 96:1418-23. [PMID: 27266349 DOI: 10.3760/cma.j.issn.0376-2491.2016.18.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To explore the expression level and location of hypoxia-inducible factor 1α (HIF-1α) in gastric cancer (GC) tissues and their relationship with clinicopathological features and clinical outcomes. METHODS From July to September 2015, 27 pairs of fresh paired GC tissues and adjacent normal tissues were gathered from the Eighth Department of General Surgery of the First Affiliated Hospital of Anhui Medical University. Quantitative real-time PCR (qRT-PCR) and Western blot were performed to detect the expression of HIF-1α mRNA and protein in these tissues. A total of 191 GC tissues and 46 randomly selected adjacent normal gastric tissues were consecutively collected between December 2006 and September 2008 from Department of General Surgery of the same hospital. Immunohistochemistry were performed on them to detect the expression of HIF-1α and CD34[described in terms of microvessel density (MVD)], and correlation of different locations of HIF-1α (in cytoplasm or nucleus) with MVD, clinicopathological features, and clinical prognosis was analyzed. RESULTS The average relative expression level of HIF-1α mRNA in GC tissues (0.625±0.170) was significantly higher than in normal adjacent tissues (0.218±0.036, t=2.336, P=0.023) by qRT-PCR. From the results of Western blot, the expression level of HIF-1α protein increased in GC tissues compared with its corresponding normal tissues. Immunohistochemistry results revealed that positive HIF-1α staining was observed in 67.54% GC tissues and 45.65% normal tissues, with significant difference (P=0.006). And 35.08% in GC and 45.65% in normal tissues were cytoplasmic positive (P=0.138); while 37.17% in GC and only 2.17% in normal tissues were nuclear positive, with significant difference (P<0.001). High differentiation group and TNM clinical early stage (Ⅰ+ Ⅱ) group had significantly higher cytoplasmic HIF-1α expression positive rate compared with low differentiation group (P=0.008) and TNM clinical intermediate-advanced stage (Ⅲ+ Ⅳ) group (P=0.019); whereas low differentiation group had significantly higher nuclear HIF-1α expression positive rate compared with high differentiation group (P=0.043). The mean MVD in the nuclear HIF-1α positive GC group (115.6 ± 7.8) was higher than that in the cytoplasmic HIF-1α positive GC group (93.1±7.5, t=2.077, P=0.040). The median follow-up time was 56(3-81)months. Kaplan-Meier survival analysis and Log-Rank test results showed that nuclear HIF-1α positive patients had a shorter survival time (median 45 months) than cytoplasmic HIF-1α positive patients (median 64 months, P<0.001). Multivariate Cox regression analysis revealed that differentiation (HR=1.713; 95% CI: 1.019-2.882), depth of invasion (tumor stage, HR=6.137; 95% CI: 1.832-20.556) and lymph node metastasis (HR=2.788; 95% CI: 1.313-5.920) were independent prognostic factors for GC (all P<0.05). CONCLUSION Different location of HIF-1α protein may be realted to the tumorigenesis and progression of GC, and may become a potential prognostic indicator of GC.
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Affiliation(s)
- Y L Wu
- Eighth Department of General Surgery, First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
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Zhang AP, Liu CF, Sun RC, Xie J, Chen XY. Homogeneous acylation of eucalyptus wood at room temperature in dimethyl sulfoxide/N-methylimidazole. Bioresour Technol 2012; 125:328-331. [PMID: 23069606 DOI: 10.1016/j.biortech.2012.08.131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 07/24/2012] [Accepted: 08/28/2012] [Indexed: 06/01/2023]
Abstract
Succinoylation and benzoylation of ball-milled eucalyptus wood using succinic anhydride and benzoyl chloride as acylating reagent, respectively, were investigated at room temperature using dimethyl sulfoxide/N-methylimidazole (DMSO/NMI) as reaction medium without additional catalysts. The effects of the corresponding acylating reagent dosage (1-5:1 for succinoylation and 0.5-5:1 for benzoylation) and reaction time (0.35-5h for succinoylation and 0.5-3h for benzoylation) on the extent of acylation, measured by weight percent gain (WPG), were studied. WPG of succinoylation and benzoylation was in the range of 70.8-144.7% and 17.3-43.1%, respectively. The efficiency of acylation at room temperature significantly increased in DMSO/NMI compared with ionic liquid 1-butyl-3-methylimidazolium chloride because of the role of NMI as solvent, base and catalyst. Fourier transform infrared (FT-IR), and solid-state cross-polarization/magic-angle spinning (CP/MAS) (13)C nuclear magnetic resonance (NMR) spectroscopy studies provided evidence for the occurrence of succinoylation and benzoylation reactions and the attachment of functional groups via ester bonds.
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Affiliation(s)
- A P Zhang
- Institute of New Energy and New Material, Key Laboratory of Biomass Energy of Guangdong Higher Education Institutes, South China Agricultural University, Guangzhou 510642, PR China
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Liu CF, Sun RC, Qin MH, Zhang AP, Ren JL, Ye J, Luo W, Cao ZN. Succinoylation of sugarcane bagasse under ultrasound irradiation. Bioresour Technol 2008; 99:1465-73. [PMID: 17446063 DOI: 10.1016/j.biortech.2007.01.062] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 01/16/2007] [Accepted: 01/16/2007] [Indexed: 05/15/2023]
Abstract
The chemical modification of sugarcane bagasse with succinic anhydride using pyridine as solvent after ultrasound irradiation was studied. The optimized parameters included ultrasound irradiating time 0-50 min, reaction time 30-120 min, succinic anhydride concentration by the ratio of dried sugarcane bagasse to succinic anhydride from 1:0.25 to 1:1.50, and reaction temperature 75-115 degrees C are required in the process. The extent of succinoylation was measured by the weight percent gain (WPG), which increased with increments of reaction time, succinic anhydride concentration, and reaction temperature. The ultrasound irradiation has a positive effect on bagasse succinoylation process. On the other hand, the ultrasonic pre-treatment application broke down the cell wall polymers, resulting in, therefore, a negative effect on the WPG. Evidences of succinoylation were also provided by FT-IR and CP MAS (13)C NMR and the results showed that the succinoylation at C-2 and C-3 occurred. The thermal stability of the succinylated bagasse decreased upon chemical modification.
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Affiliation(s)
- C F Liu
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, China
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Ren JL, Peng F, Sun RC, Liu CF, Cao ZN, Luo W, Tang JN. Synthesis of cationic hemicellulosic derivatives with a low degree of substitution in dimethyl sulfoxide media. J Appl Polym Sci 2008. [DOI: 10.1002/app.28256] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Xu F, Geng ZC, Liu CF, Ren JL, Sun JX, Sun RC. Structural characterization of residual lignins isolated with cyanamide-activated hydrogen peroxide from various organosolvs pretreated wheat straw. J Appl Polym Sci 2008. [DOI: 10.1002/app.25156] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Jiang JX, Zhu LW, Zhang WM, Sun RC. Characterization of Galactomannan Gum from Fenugreek (Trigonella foenum-graecum) Seeds and Its Rheological Properties. INT J POLYM MATER PO 2007. [DOI: 10.1080/00914030701323745] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Xu F, Liu CF, Ren JL, Sun JX, Sun RC, Curling S, Fowler P, Baird MS. Fractional Separation and Structural Characterization of Chlorophyll and Lignin from Perennial Ryegrass (L. perenne) and Cocksfoot Grass (D. glomerata). SEP SCI TECHNOL 2007. [DOI: 10.1080/01496390701242137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Liu CF, Sun RC, Zhang AP, Ren JL, Wang XA, Qin MH, Chao ZN, Luo W. Homogeneous modification of sugarcane bagasse cellulose with succinic anhydride using a ionic liquid as reaction medium. Carbohydr Res 2007; 342:919-26. [PMID: 17324384 DOI: 10.1016/j.carres.2007.02.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Revised: 02/01/2007] [Accepted: 02/05/2007] [Indexed: 10/23/2022]
Abstract
The homogeneous chemical modification of sugarcane bagasse cellulose with succinic anhydride using 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid as a reaction medium was studied. Parameters investigated included the molar ratio of succinic anhydride/anhydroglucose units in cellulose in a range from 2:1 to 14:1, reaction time (from 30 to 160min), and reaction temperature (between 60 and 110 degrees C). The succinylated cellulosic derivatives were prepared with a low degree of substitution (DS) ranging from 0.071 to 0.22. The results showed that the increase of reaction temperature, molar ratio of SA/AGU in cellulose, and reaction time led to an increase in DS of cellulose samples. The products were characterized by FT-IR and solid-state CP/MAS (13)C NMR spectroscopy, and thermal analysis. It was found that the crystallinity of the cellulose was completely disrupted in the ionic liquid system under the conditions given. The data also demonstrated that homogeneous modification of cellulose with succinic anhydride in AmimCl resulted in the production of cellulosic monoester. The thermal stability of the succinylated cellulose decreased upon chemical modification.
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Affiliation(s)
- C F Liu
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
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Liu CF, Xu F, Sun JX, Ren JL, Curling S, Sun RC, Fowler P, Baird MS. Physicochemical characterization of cellulose from perennial ryegrass leaves (Lolium perenne). Carbohydr Res 2006; 341:2677-87. [PMID: 16934239 DOI: 10.1016/j.carres.2006.07.008] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 07/03/2006] [Accepted: 07/13/2006] [Indexed: 11/24/2022]
Abstract
In this study, we investigated the physicochemical properties of the cellulosic preparations obtained from both untreated perennial ryegrass leaves and de-juiced leaves. It was found that treatment at 22 degrees C with 18% NaOH and 18% KOH for 2h, and 10% NaOH and 10% KOH for 16 h yielded 28.2%, 28.8%, 22.7%, 23.4%, respectively, of 'cellulose' residue from untreated ryegrass leaves and 35.7%, 36.8%, 32.8% and 34.6%, respectively, from the de-juiced leaves. For each cellulosic fraction, the glucose content was 71.6%, 69.6%, 67.8%, 66.7%, 69.7%, 68.6%, 63.9% and 61.7%, respectively. The structure of the cellulose samples was examined using FTIR and CP/MAS (13)C NMR spectroscopy and X-ray diffraction. The cellulosic preparations were free of bound lignin except for noticeable amounts of residual hemicelluloses (28.4-38.3%), and had intrinsic viscosities between 275.1 and 361.0 mL/g, along with molecular weights from 144,130 to 194,930 g/mol. This study found that the cellulose samples isolated from both de-juiced ryegrass leaves and the untreated leaves had a much lower percent crystallinity (33.0-38.6%) than that from wood-based fibres (60-70%) and had much shorter fibres (0.35-0.49 mm) than those of either cereal straws, bagasse or wood. In addition, a partial disruption of the hydrogen bonds and microfibrils may occur during the de-juicing process by mechanical activity, which results in a decreased cellulose crystallinity and fibre length. These findings are significant in relation to hydrolysing ryegrass cellulose for bio-ethanol production.
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Affiliation(s)
- C F Liu
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China
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Geng ZC, Sun JX, Liang SF, Zhang FY, Zhang YY, Xu F, Sun RC. Characterization of Water- and Alkali-Soluble Hemicellulosic Polymers from Sugarcane Bagasse. International Journal of Polymer Analysis and Characterization 2006. [DOI: 10.1080/10236660600649095] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Z. C. Geng
- a The North-Western University of Agricultural and Forest Sciences and Technology , Yangling , China
| | - J. X. Sun
- a The North-Western University of Agricultural and Forest Sciences and Technology , Yangling , China
| | - S. F. Liang
- a The North-Western University of Agricultural and Forest Sciences and Technology , Yangling , China
| | - F. Y. Zhang
- a The North-Western University of Agricultural and Forest Sciences and Technology , Yangling , China
| | - Y. Y. Zhang
- a The North-Western University of Agricultural and Forest Sciences and Technology , Yangling , China
| | - F. Xu
- b State Key Laboratory of Pulp and Paper Engineering , South China University of Technology , Guangzhou , China
| | - R. C. Sun
- b State Key Laboratory of Pulp and Paper Engineering , South China University of Technology , Guangzhou , China
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Xu F, Geng ZC, Sun JX, Liu CF, Ren JL, Sun RC, Fowler P, Baird MS. Fractional and structural characterization of hemicelluloses from perennial ryegrass (Lolium perenne) and cocksfoot grass (Dactylis glomerata). Carbohydr Res 2006; 341:2073-82. [PMID: 16750181 DOI: 10.1016/j.carres.2006.04.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2006] [Revised: 04/06/2006] [Accepted: 04/19/2006] [Indexed: 11/16/2022]
Abstract
Sequential three-stage treatments with 80% EtOH containing 0.2% NaOH, 2.5% H2O2-0.2% EDTA containing 1.5% NaOH and 2.5% H2O2-0.2% TAED containing 1.0% NaOH at 75 degrees C for 3h released 8.0% and 10.4%, 79.1% and 77.0% and 12.9% and 12.5% of the original hemicelluloses from perennial grass and cocksfoot grass, respectively. It was found that the four alkaline peroxide-soluble hemicellulosic fractions contained higher amounts of xylose (33.4-38.2%), uronic acids (9.3-15.3%) and rhamnose (3.0-3.9%), but were lower in glucose (25.1-28.3%), galactose (13.3-15.3%) and mannose (0.4-1.5%) than those of the two alkaline EtOH-soluble hemicellulosic fractions in which glucose (32.9-36.0%), xylose (20.1-22.6%), arabinose (14.1-21.4%), galactose (16.6-19.9%), mannose (4.1-9.9%) and uronic acids (3.4-7.4%) were the major sugar components. 13C NMR spectroscopy confirmed that all the six hemicellulosic fractions were composed of galactoarabinoxylans, 4-O-methylglucuronoarabinoxylans and beta-glucan. In addition, the studies showed that the four alkaline peroxide-soluble hemicellulosic fractions were more linear and acidic and had larger molecular weights (Mw, 28,400-38,650 g mol(-1)) than those of the two alkaline EtOH-soluble hemicellulosic fractions (Mw, 16,460-17,420 g mol(-1)).
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Affiliation(s)
- F Xu
- College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China
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Xu F, Sun JX, Liu CF, Sun RC. Comparative study of alkali- and acidic organic solvent-soluble hemicellulosic polysaccharides from sugarcane bagasse. Carbohydr Res 2005; 341:253-61. [PMID: 16313892 DOI: 10.1016/j.carres.2005.10.019] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Accepted: 10/21/2005] [Indexed: 11/27/2022]
Abstract
Two-stage treatments of sugarcane bagasse with mild alkali and acidic 1,4-dioxane were performed. Pretreatment with 1M NaOH aqueous solution at 20, 25, 30, 35, and 40 degrees C for 18 h released 55.5%, 57.3%, 59.1%, 60.9%, and 62.1% of the original hemicelluloses, respectively. Post-treatment of the corresponding alkali-treated residue with 1,4-dioxane-2M HCl (9:1, v/v) at 87 degrees C for 2h, respectively, degraded 11.6%, 11.9%, 11.4%, 10.9%, and 10.6% of hemicelluloses (% dry starting material). It was found that the five alkali-soluble hemicellulosic preparations contained a much higher amounts of xylose (78.0-82.2%) and slightly higher uronic acids (4.8-5.8%), mainly 4-O-methyl-alpha-d-glucopyranosyluronic acid, but were lower in arabinose (9.3-11.7%) and glucose (2.2-4.1%) than those of the corresponding five acidic dioxane-degraded hemicellulosic fractions in which xylose (44.9-46.8%), arabinose (35.9-38.1%), and glucose (13.0-13.7%) were the major sugar constituents. The studies revealed that the five alkali-soluble hemicellulosic preparations were more linear and acidic, and had a large molecular weight (35,200-37,430 g mol(-1)) than those of the hemicellulosic fractions (12,080-13,320 g mol(-1)) degraded during the acidic dioxane post-treatment. This demonstrated that the post-treatment with acidic dioxane under the condition used resulted in substantial degradation of the hemicellulosic polymers. The 10 hemicellulosic samples were further characterized by FT-IR and 1H and 13C NMR spectroscopy, GPC and thermal analysis, and the results are reported.
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Affiliation(s)
- F Xu
- College of Forestry, North-Western Science and Technology University of Agriculture and Forestry, Yangling 712100, China
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Sun XF, Xu F, Zhao H, Sun RC, Fowler P, Baird MS. Physicochemical characterisation of residual hemicelluloses isolated with cyanamide-activated hydrogen peroxide from organosolv pre-treated wheat straw. Bioresour Technol 2005; 96:1342-1349. [PMID: 15792581 DOI: 10.1016/j.biortech.2004.11.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Revised: 10/18/2004] [Accepted: 11/16/2004] [Indexed: 05/24/2023]
Abstract
Seven residual hemicellulosic preparations (19.6-45.0% of the original hemicelluloses) were extracted from wheat straw pre-treated with various organic solvents using 1.8% H2O2-0.18% cyanamide at 50 degrees C and pH 10.0 for 4 h. Their chemical compositions and physicochemical properties were determined using GC, HPLC, GPC, FT-IR and 13NMR spectroscopy. The results indicated that all the residual hemicellulosic preparations were heteropolysaccharides containing xylose, glucose, arabinose, galactose, mannose, rhamnose and 4-O-methyl-alpha-D-glucopyranosyluronic acid. The predominant monosaccharide was xylose, ranging between 67.7% and 81.9% of the total neutral sugars, composed mainly of L-arabino-(4-O-methyl-D-glucurono)-D-xylan. The content of contaminant lignin in the isolated residual hemicelluloses was 2.89-5.31%. The Mw values of the two residual hemicellulosic preparations H6 and H7 (42,710 and 44,080 g mol-1, respectively) obtained from the aqueous-alcohol pre-treated straw were much higher than those of H1-H5 (12,980-15,950 g mol-1) extracted from the organic acid pre-treated straw.
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Affiliation(s)
- Xiao Feng Sun
- College of Forestry, The North-Western University of Agricultural and Forest Sciences and Technology, Yangling 712100, China
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Sun JX, Xu F, Geng ZC, Sun XF, Sun RC. Comparative study of cellulose isolated by totally chlorine-free method from wood and cereal straw. J Appl Polym Sci 2005. [DOI: 10.1002/app.21728] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Sun XF, Xu F, Sun RC, Fowler P, Baird MS. Characteristics of degraded cellulose obtained from steam-exploded wheat straw. Carbohydr Res 2005; 340:97-106. [PMID: 15620672 DOI: 10.1016/j.carres.2004.10.022] [Citation(s) in RCA: 234] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Accepted: 10/27/2004] [Indexed: 11/19/2022]
Abstract
The isolation of cellulose from wheat straw was studied using a two-stage process based on steam explosion pre-treatment followed by alkaline peroxide post-treatment. Straw was steamed at 200 degrees C, 15 bar for 10 and 33 min, and 220 degrees C, 22 bar for 3, 5 and 8 min with a solid to liquid ratio of 2:1 (w/w) and 220 degrees C, 22 bar for 5 min with a solid to liquid ratio of 10:1, respectively. The steamed straw was washed with hot water to yield a solution rich in hemicelluloses-derived mono- and oligosaccharides and gave 61.3%, 60.2%, 66.2%, 63.1%, 60.3% and 61.3% of the straw residue, respectively. The washed fibre was delignified and bleached by 2% H2O2 at 50 degrees C for 5 h under pH 11.5, which yielded 34.9%, 32.6%, 40.0%, 36.9%, 30.9% and 36.1% (% dry wheat straw) of the cellulose preparation, respectively. The optimum cellulose yield (40.0%) was obtained when the steam explosion pre-treatment was performed at 220 degrees C, 22 bar for 3 min with a solid to liquid ratio of 2:1, in which the cellulose fraction obtained had a viscosity average degree of polymerisation of 587 and contained 14.6% hemicelluloses and 1.2% klason lignin. The steam explosion pre-treatment led to a significant loss in hemicelluloses and alkaline peroxide post-treatment resulted in substantial dissolution of lignin and an increase in cellulose crystallinity. The six isolated cellulose samples were further characterised by FT-IR and 13C-CP/MAS NMR spectroscopy and thermal analysis.
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Affiliation(s)
- X F Sun
- College of Forestry, The North-Western University of Agricultural and Forest Sciences and Technology, Yangling 712100, China
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Sun XF, Sun RC, Sun JX. Acetylation of sugarcane bagasse using NBS as a catalyst under mild reaction conditions for the production of oil sorption-active materials. Bioresour Technol 2004; 95:343-350. [PMID: 15288278 DOI: 10.1016/j.biortech.2004.02.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Sugarcane bagasse was esterified with acetic anhydride using N-bromosuccinimide as a catalyst under mild conditions in a solvent free system. The extent of acetylation was measured by weight percent gain, which varied from 2.1% to 24.7% by changing the reaction temperature (25-130 degrees C) and duration (0.5-6.0 h). N-Bromosuccinimide was found to be a novel and highly effective catalyst for acetylation of hydroxyl groups in bagasse. At a concentration of 1% of the catalyst in acetic anhydride, a weight percent gain of 24.7% was achieved at 120 degrees C for 1 h, compared with 5.1% for the un-catalyst reaction under the same reaction condition. FT-IR and CP-MAS 13C-NMR studies produced evidence for acetylation. The thermal stability of the products decreased slightly upon chemical modification, but no significant decrease in thermal stability was observed for WPG > or = 24.7%. More importantly, the acetylation significantly increased hydrophobic properties of the bagasse. The oil sorption capacity of the acetylated bagasse obtained at 80 degrees C for 6 h, was 1.9 times higher than the commercial synthetic oil sorbents such as polypropylene fibres. Therefore, these oil sorption-active materials can be used to substitute non-biodegradable materials in oil spill cleanup.
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Affiliation(s)
- X F Sun
- College of Forestry, The North-Western Sciences and Technology University of Agricultural and Forestry, Yangling 712100, China
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Sun RC, Salisbury D, Tomkinson J. Chemical composition of lipophilic extractives released during the hot water treatment of wheat straw. Bioresour Technol 2003; 88:95-101. [PMID: 12576001 DOI: 10.1016/s0960-8524(02)00290-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Treatment of wheat straw with hot water at 80-95 degrees C for 0.5 h at pH 6.0-8.0 released 41.0-53.0% of the original lipophilic extractives. The chemical compositions of six lipophilic extractives were determined by GC on a medium-length high-temperature capillary column without derivatization, thus giving a method for direct determination of individual components of free fatty and resin acids, sterols, waxes, sterol esters, and triglycerides. The extracts contained 68.7-75.8% lipophilic substances, comprising mainly free fatty acids (25.8-48.4%), waxes (9.4-27.0%), sterols (4.1-8.0%), triglycerides (3.3-11.0%), and sterol esters (2.6-5.1%). Minor amounts of diglycerides (0.3-0.5%), resin acid (0.5-3.1%), and phenolic compounds (0.9-3.6%) were also quantitatively determined in the extractives.
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Affiliation(s)
- R C Sun
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China.
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Sun RC, Sun XF, Ma XH. Effect of ultrasound on the structural and physiochemical properties of organosolv soluble hemicelluloses from wheat straw. Ultrason Sonochem 2002; 9:95-101. [PMID: 11794024 DOI: 10.1016/s1350-4177(01)00102-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Effect of ultrasound on the yield and physiochemical properties of hemicelluloses from wheat straw using 0.5 M NaOH in 60% aqueous methanol has been comparatively studied. The results showed that applying sonication for 5, 10, 15, 20, 25, 30, and 35 min resulted in an increasing yield of hemicelluloses by 2.9%, 3.9%, 6.0%, 8.6%, 8.6%, 8.6%, and 9.2% of the original hemicelluloses, respectively, in comparison with the experiment performed without ultrasonic assistance. The hemicelluloses isolated by ultrasound-assisted extraction, showed a slightly lower molecular weight, associated lignin, and thermal stability during the first stage of decomposition, but slightly more linear as compared to the hemicelluloses obtained by classical method without ultrasonic irradiation. No substantial differences in the main structure features between the hemicellulosic preparations isolated by classical or ultrasound-assisted extractions were found.
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Affiliation(s)
- R C Sun
- State Key Laboratory of Pulp and Paper Engineering, College of Paper and Environment Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China.
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Sun RC, Sun XF, Zhang SH. Quantitative determination of hydroxycinnamic acids in wheat, rice, rye, and barley straws, maize stems, oil palm frond fiber, and fast-growing poplar wood. J Agric Food Chem 2001; 49:5122-5129. [PMID: 11714291 DOI: 10.1021/jf010500r] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new method has been developed for the quantitative determination of hydroxycinnamic acids participating in ester or ether linkages to the cell wall polymers. The method is based on mild alkaline hydrolysis followed by acid hydrolysis or mild alkaline hydrolysis, which partially removed esterified phenolic acids, and high-temperature concentrated alkaline treatment, which cleaved both the ester and ether linkages. It was found that traditional mild alkaline hydrolysis and acid hydrolysis released only part of the ester- and ether-linked phenolic acids, respectively. Approximately half (44.0-47.9%) of the total ester-linked p-coumaric acid and 18.2-32.6% of the total esterified ferulic acid remained ester-linked to the mild alkali-soluble lignin polymers, and 55.0-72.0% of the total ether-linked p-coumaric acid and 37.5-53.8% of the total ether-linked ferulic acid remained ether-linked to the solubilized lignin molecules after the acid hydrolysis. To correct this, a second mild alkaline hydrolysis of the alkali-soluble lignin preparations and acid hydrolysis of the solubilized lignin fractions, obtained from the first acid hydrolysis of the cell wall materials, was investigated. On the basis of this new method, a majority of the cell wall p-coumaric acid (55.8-81.5%) was found to be ester-linked to cell wall components, mainly to lignin, and about half of the cell wall ferulic acid is etherified through its phenolic oxygen to the cell wall lignin component, whereas the remainder is esterified to the cell wall hemicelluloses and/or lignin in different plant materials.
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Affiliation(s)
- R C Sun
- State Key Laboratory of Pulp and Paper Engineering, College of Paper and Environment Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China.
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Sun RC, Sun XF, Wen JL. Fractional and structural characterization of lignins isolated by alkali and alkaline peroxide from barley straw. J Agric Food Chem 2001; 49:5322-5330. [PMID: 11714323 DOI: 10.1021/jf010645y] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A sequential treatment of dewaxed barley straw with sodium hydroxide, different concentrations of hydrogen peroxide, and potassium hydroxide/sodium borate degraded various proportions of the original lignin and solubilized different amounts of the original hemicelluloses. The isolated lignin fractions were subjected to comprehensive structural characterization by UV, FT-IR, and (13)C NMR spectroscopy, and their chemical compositions were analyzed by alkaline nitrobenzene oxidation. All of the lignin fractions were typical of grass lignins and had weight-average molecular weights between 1750 and 2190. It was found that the peroxide treatment at low concentrations (< or =2.0%) resulted in a slight increase in the amount of carboxyl groups, whereas the treatment at a relatively high concentration of alkaline peroxide, such as at 3.0% H(2)O(2), led to a noticeable oxidation of the lignins, as shown by an increase of carboxyl groups. Moreover, the results obtained indicated that the successive treatments with alkali and alkaline peroxide under the conditions used did not significantly affect the beta-O-4 structures of lignins. Substantial amounts of etherified ferulic acids were cleaved by the sequential treatments with alkaline peroxide, as shown in the (13)C NMR spectra. The results underscore the structural differences between alkali- and alkaline peroxide-soluble lignins from barley straw.
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Affiliation(s)
- R C Sun
- State Key Laboratory of Pulp and Paper Engineering, College of Paper and Environment Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China.
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Tang YD, Yang YJ, Zhang P, Ruan YM, Lu SQ, Sun RC, Wang PH, Gao RL, Chen JL, Chen ZJ. [Comparative effects of carvedilol and metoprolol in preventing from left ventricular remodeling after acute myocardial infarction in rats]. Zhongguo Yi Xue Ke Xue Yuan Xue Bao 2001; 23:476-80. [PMID: 12905866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
OBJECTIVE To compare the effects of carvedilol and metoprolol in preventing from left ventricular remodeling (LVRM) after acute myocardial infarction (AMI) in rats. METHODS Twenty-four hours after ligating left coronary artery, 105 surviving female SD rats were randomly assigned to AMI control, carvedilol 1 mg/(kg.d) and metoprolol 2 mg/(kg.d) groups. Sham-operated rats (n = 16) were selected randomly as non-infarction control. After four weeks of drugs therapy, hemodynamic studies and pathologic analysis were performed. Exclusive of MI size < 35% or > 55%, complete experimental variables were obtained in 46 rats, which were comprised of AMI (n = 11), carvedilol (n = 12), metoprolol (n = 11), and Sham-operated (n = 12) groups. RESULTS Compared with sham-operated group, left ventricular (LV) end diastolic pressure (LVEDP), volume (LVV) and weight (LVW), were all significantly increased (P < 0.05-0.001), while maximal rate of rise and fall (+/- dp/dt) of LV pressure as well as their corrected values (+/- dp/dt/LVSP) were all significantly decreased (P < 0.01-0.001) in AMI group. In comparison with AMI group, the LVEDP and LVV were all significantly decreased (all P < 0.001), while +/- dp/dt and +/- dp/dt/LVSP were significantly increased (P < 0.05-0.001) in both carvedilol and metoprolol group, with LVW and RVW only decreased in carvedilol group (P < 0.05-0.01). CONCLUSIONS 1. Carvedilol can effectively attenuate LVRM, and improve hemodynamics and LV function after AMI in rats, 2. Metoprolol has equivalent beneficial effects as carvedilol on hemodynamics, LV dilatation and function, but not LV hypertrophy.
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Affiliation(s)
- Y D Tang
- Department of Coronary Heart Disease, Cardiovascular Institute, FuWai Hospital, CAMS, PUMC, Beijing 100037, China.
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Sun RC, Tomkinson J, Zhu W, Wang SQ. Delignification of maize stems by peroxymonosulfuric acid, peroxyformic acid, peracetic acid, and hydrogen peroxide. 1. Physicochemical and structural characterization of the solubilized lignins. J Agric Food Chem 2000; 48:1253-1262. [PMID: 10775381 DOI: 10.1021/jf990646e] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Water-treated maize stems were subjected to delignification with peroxymonosulfuric acid at 20 degrees C for 144 h, with peroxyformic acid at 80 degrees C for 6 h, with peracetic acid at 50 degrees C for 6 h, and with 2% hydrogen peroxide at 45 degrees C for 12 h at pH 1.5, 4.4, 9.5, 11.5, 12.0, and 12.6, respectively, which solubilized 47.1, 91.3, 33.3, 16.6, 15.9, 17.4, 86.2, 87.7, and 91. 3% of the original lignin, respectively. Substantial lignins were released during the treatment with peroxyformic acid and hydrogen peroxide at pH > or =11.5, whereas an insignificant effect on delignification was observed by using peroxymonosulfuric acid, peracetic acid, and hydrogen peroxide under acidic, natural, and weakly alkaline media conditions. The structures of the isolated lignin preparations were investigated by chemical analysis, gel permeation chromatography, and UV, FT-IR, and (13)C NMR spectroscopy.
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Affiliation(s)
- R C Sun
- The BioComposites Centre, University of Wales, Bangor, Gwynedd LL57 2UW, United Kingdom
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Abstract
(R)-alpha-Methyl-3-pyridinebutanamine (5) was required as a key intermediate for production of the PAF antagonist [(R)-(E,E)-5-(4-methoxyphenyl)-N-1- methyl-4-(3-pyridinyl)butyl-2,4-decadienamide (1). A method meeting the requirements of technical simplicity and economic viability was developed using an aminotransferase ex. B. megaterium to catalyze a kinetic resolution of racemic alpha-methyl-3-pyridinebutanamine (3). 5-(3-Pyridinyl)-2-pentanone (4) produced from the (S)-enantiomer, with co-generation of alanine, is recycled by catalytic reductive amination.
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Affiliation(s)
- D L Coffen
- Roche Research Center, Hoffmann-La Roche Inc., Nutley, NJ 07110
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