Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros










Intervalo de ano de publicação
2.
Front Plant Sci ; 14: 1093678, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36968380

RESUMO

Shrubs are the main species in desert ecosystems. Better understanding shrubs fine root dynamics and its contribution to soil organic carbon (SOC) stocks can improve the accuracy of carbon sequestration estimation and provide basic data for the calculation of carbon sequestration potential. The ingrowth core method was used to investigate the fine root (< 1 mm in diameter) dynamics of Caragana intermedia Kuang et H. C. Fu plantation with different age (4-, 6-, 11-, 17-, and 31-year-old) in Gonghe Basin of the Tibetan Plateau, and the annual fine root mortality was used for calculation the annual carbon input to SOC pool. The results showed that fine root biomass, production, and mortality first increased and then decreased as the plantation age increased. Fine root biomass peaked in 17-year-old plantation, production and mortality peaked in 6-year-old plantation, and turnover rate of 4- and 6-year-old plantations were significantly higher than other plantations. Fine root production and mortality were negative correlated with soil nutrients at depth of 0-20 and 20-40 cm. The variation range of carbon input by fine root mortality across different plantation age at 0-60 cm soil depth was 0.54-0.85 Mg ha-1 year-1, accounting for 2.40-7.54% of the SOC stocks. C. intermedia plantation has a strong carbon sequestration potential from long time scale. Fine roots regenerate faster in young stands and lower soil nutrients environment. Our results suggest that the influences of plantation age and soil depth should be taken into account when calculating the contribution of fine root to SOC stocks in desert ecosystems.

3.
Front Chem ; 11: 1347215, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38274898

RESUMO

For the aroma enhancement research of heated cigarettes, it is worth exploring whether tobacco can be pyrolyzed into pyrolysis liquids containing a large number of volatile aroma components. In this study, tobacco pyrolysis liquids were prepared in subcritical/supercritical ethanol, and their applications in the aroma enhancement of heated cigarettes were investigated. The optimal conditions of supercritical liquefaction reactions were determined by optimizing the reaction time, liquid/solid mass ratio and temperature conditions. Moreover, the effect of supercritical liquefaction conditions on volatile aroma components in tobacco pyrolysis liquids was investigated by GC-MS. The results indicated that the reaction temperature had the most significant impact on the tobacco pyrolysis reaction, and higher reaction temperature promoted the pyrolysis conversion of tobacco, resulting in enhanced tobacco conversion and a high content of volatile components in the tobacco pyrolysis liquid. The optimal reaction conditions for the preparation of tobacco pyrolysis liquid were found to be a temperature of 220°C, a liquid/solid mass ratio = 15, and a 2-h reaction time. Meanwhile, the content of ester compounds and nicotine in the tobacco pyrolysis liquid increased significantly with the increase of reaction temperature. Sub/supercritical ethanol treatment significantly destroyed the surface structure of tobacco, and the degree of tobacco depolymerization increased when temperature rised. The analysis of aroma compounds in the smoke of heated cigarettes indicated that the tobacco pyrolysis liquid could significantly increase the release of aromatic substances and has a significant aroma-enhancing effect. This article proposed and prepared tobacco pyrolysis liquid in subcritical/supercritical ethanol and explored its potential application in the aroma enhancement of heated cigarettes, offering a new route for flavor enhancement technology for this type of product.

5.
Chemistry ; 25(4): 1029-1036, 2019 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-30303572

RESUMO

Tailoring the morphology of a specific crystalline material through distinct crystal growth mechanisms (classical and nonclassical) is challenging. Herein, we report the two unique morphologies of a medium-pore (10×8-ring) zeolite, ZSM-57, prepared by employing an identical organic structure-directing agent (OSDA) and different inorganic cations, namely Na+ and K+ , denoted as ZSM-57-Na (pentagonal nanoplates) and ZSM-57-K (pentagonal nanoprisms), respectively. The tunable twin domain size and twin boundaries in both samples have been unraveled at the atomic level by electron crystallography. It is of significance to note that the 10-ring pore openings run perpendicular to the pentagonal nanoplates and nanoprisms. Moreover, the distinct crystal growth mechanisms, which result in the different unique morphologies and tunable twin domains, were further determined by electron crystallography combined with other techniques. Nonclassical growth involving the aggregation of amorphous aluminosilicate nanoparticles to the smooth ZSM-57-Na crystal surface dominates the ZSM-57-Na crystallization process. For the ZSM-57-K sample, the classical layer-by-layer growth through the addition of silica molecules to advancing steps on the crystal surface dominates the ZSM-57-K crystallization process. The different morphologies of both samples result in the distinct catalytic lifespan of the methanol conversion and selectivity of lower olefins.

6.
Exp Ther Med ; 16(2): 886-890, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30116341

RESUMO

This study explored the effects of probucol on atherosclerotic plaques and soluble thrombomodulin in patients with coronary heart disease (CHD). Five hundred and eighty-three patients with CHD who were admitted to Jining First People's Hospital from February 2013 to February 2014. A total of 300 of them received conventional treatment, and were assigned to the control group, while the remaining 283 patients were treated with probucol in addition to the conventional treatment, and were assigned to the observation group. A retrospective analysis was performed on the total cholesterol levels, atherosclerotic plaque sizes, and soluble thrombomodulin levels. Probucol was administered at a dose of 500 mg twice a day for a period of 16 weeks. The total cholesterol level decreased gradually over time during the treatment. After 8 weeks of treatment, the total cholesterol level in the observation group was lower than that in the control group (P<0.05). After 8 weeks of treatment, the atherosclerotic plaque area in the observation group decreased compared with that before treatment (P<0.05). After 8 and 16 weeks of treatment, the plaque area in the observation group was smaller than that in the control group (P<0.05). The soluble thrombomodulin level at any time-point after treatment was lower than that before treatment in both groups (P<0.05). At the same time-point, the level in the observation group was lower than that in the control group (P<0.05). The total cholesterol and soluble thrombomodulin levels were positively correlated with the atherosclerotic plaque area (r=0.841, P=0.001; r=0.725, P=0.008). When patients with CHD were treated with probucol in addition to the conventional treatment, a reduction of the atherosclerotic plaque area, as well as a decrease of both the total cholesterol and soluble thrombomodulin levels, was observed. Overall, patients with CHD experienced improved symptoms following treatment with probucol.

7.
Biomed Pharmacother ; 106: 117-124, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29957461

RESUMO

Hypoxia/reoxygenation (H/R) often results in cellular oxidative stress and the subsequent apoptosis of cardiac microvascular endothelial cells (CMECs). More recently, studies have highlighted the therapeutic effects of matrine on various cardiovascular diseases. Thus, the aim of the present study was to investigate the underlying mechanism and effects of matrine on hypoxia/reoxygenation (H/R)-induced apoptosis of CMECs in rats. CMECs from Sprague Dawley (SD) rats were primarily treated with H/R, ld (low-dose, 0.5 mg/mL)-Ma + H/R, md (middle-dose, 1 mg/mL)-Ma + H/R, hd (high-dose, 2 mg/mL)-Ma + H/R, Ma + AG490 + H/R (2 mg/mL matrine and 50 µmol/L AG490, a JAK2/STAT3 signaling pathway inhibitor), and AG490 + H/R in an attempt to identify the underlying regulatory mechanisms of matrine. MTT assay was applied to determine cell viability. Hoechst staining was performed to detect the morphology of apoptotic CMECs, while cell cycle and the rate of apoptosis rate were determined by flow cytometry means. The mRNA and protein expression of the JAK2/STAT3 signaling pathway and apoptosis related genes were determined through the use of RT-qPCR and western blot assay methods respectively. An in vitro angiogenesis assay was employed to evaluate the value of matrine in tube formation. CMECs treated with ld-Ma+H/R, md-Ma+H/R, hd-Ma+H/R and Ma + AG490+H/R exhibited higher cell viability, greater cell ratio at the S phase, higher expression levels of p-JAK2 and p-STAT3, increased tube formation ability, and a lower apoptosis rate, with a lower ratio of cells at the G1 phase and Bax/Bcl-2 ratio. Meanwhile, the rats treated with AG490+H/R exhibited opposite results. Taken together, the key findings of the present study suggest that matrine inhibits the H/R-induced apoptosis of CMECs in rats via the JAK2/STAT3 signaling pathway, highlighting its therapeutic potential for H/R injury.


Assuntos
Alcaloides/farmacologia , Apoptose/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Janus Quinase 2/metabolismo , Microvasos/efeitos dos fármacos , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Quinolizinas/farmacologia , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Hipóxia Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Microambiente Celular , Citoproteção , Relação Dose-Resposta a Droga , Células Endoteliais/enzimologia , Células Endoteliais/patologia , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Janus Quinase 2/antagonistas & inibidores , Janus Quinase 2/genética , Microvasos/enzimologia , Microvasos/patologia , Traumatismo por Reperfusão Miocárdica/enzimologia , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/patologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos Sprague-Dawley , Pontos de Checagem da Fase S do Ciclo Celular/efeitos dos fármacos , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/genética , Tirfostinas/farmacologia , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo , Matrinas
8.
PLoS One ; 10(5): e0124456, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25946170

RESUMO

The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil "fertile islands" were formed, and the "fertile islands" were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous shrub.


Assuntos
Caragana/crescimento & desenvolvimento , Solo/química , Conservação dos Recursos Naturais/métodos , Nitrogênio/análise , Fósforo/análise , Potássio/análise , Tibet
9.
Artigo em Chinês | MEDLINE | ID: mdl-21619814

RESUMO

OBJECTIVE: To study the prevalence of occupational musculoskeletal disorders (OMSDs) in a shipyard and explore the relationship between type of work, age, length of service and OMSDs by cross sectional epidemiological survey. METHODS: 1570 workers from a shipyard were selected as survey objects, and a revised Northern Europe Standardized Questionnaire was used to investigate OMSDs. 253 technicians and clerks in the shipyard were selected as controls. RESULTS: OMSDs in these workers primarily located in waist, neck and shoulder, prevalence were 58.0%, 54.6% and 44.3% respectively; There were significant differences among workers of different types of work (P < 0.05) in prevalence and the cumulative parts number of OMSDs. The control group in this study also showed a higher prevalence of neck, shoulder and waist OMSDs. Female workers had higher prevalence of OMSDs in neck and shoulder compared with male workers (P < 0.05). As well there was significant correlation between age and OMSDs prevalence except the wrist and ankle disorders (P < 0.05), OMSDs prevalence increased with years. In addition, there was correlation between length of service and OMSDs prevalence, the group of ≤ 5 years had the lowest prevalence and the prevalence of low-back, neck and shoulder increased with service years. CONCLUSION: The OMSDs in workers engaged in shipyard are serious, the length of service, age, gender and type of work seem to be the risk factors, and it seems reasonable that the ergonomics intervention in the above aspects should be necessary for the prevention of OMSDs.


Assuntos
Doenças Musculoesqueléticas/epidemiologia , Doenças Profissionais/epidemiologia , Adolescente , Adulto , Feminino , Humanos , Indústrias , Masculino , Pessoa de Meia-Idade , Prevalência , Navios , Inquéritos e Questionários , Adulto Jovem
10.
Artigo em Chinês | MEDLINE | ID: mdl-21619839

RESUMO

OBJECTIVE: To investigate the usability of quick exposure check (Quick Exposure Check, QEC) for the field assessment of occupational musculoskeletal disorder risk factors. METHOD: In the shipyard and automobile manufacturing plants, QEC was used to observe the operations among workers with different jobs and to assess the work loads of workers. On the basis of results, the reliability of QEC was evaluated, and the correlation between QEC scores and morbidities of musculoskeletal disorders in workers was analyzed. RESULTS: The inter-observer reliability (ICC) was in the range from 0.737 to 1.000, and intra-observer reliability (Spearman coefficient) was from 0.605 to 1.000. The order of exposure levels to risk factors of workers engaged in different jobs (QEC scores) in the shipyard factory was plumbers > assemblers > welders; The order of exposure levels to risk factors of workers engaged in different jobs (QEC scores) in the automobile factory was welders > punching workers > machinists > casters > assemblers. In different body parts, the exposure level at back and neck parts was the highest and the exposure level at the shoulder and wrist parts was the second. The regression analysis between QEC scores of body parts and the morbidities of musculoskeletal disorders showed that there was a good correlation between exposure levels and morbidities, the coefficients (r(2)) at the shoulder, wrist, and back (static work) were 0.670, 0.740 and 0.958, respectively (P < 0.05). CONCLUSION: The QEC method is suitable and reliable as demonstrated by the field assessment on the exposure to risk factors in shipyard and automobile workers, and its results is correlated closely to the disease prevalence.


Assuntos
Doenças Musculoesqueléticas/epidemiologia , Doenças Profissionais/epidemiologia , Saúde Ocupacional , Local de Trabalho , Adulto , Estudos Transversais , Humanos , Exposição Ocupacional/efeitos adversos , Prevalência , Medição de Risco , Fatores de Risco , Carga de Trabalho
11.
Artigo em Chinês | MEDLINE | ID: mdl-20853678

RESUMO

OBJECTIVE: To explore the norms of treatment of acute organophosphorus pesticide poisoning (AOPP), and observe the curative effect. METHODS: On basis of the pre-research, the norms of treatment of AOPP were summarized, and a multi-center clinical trial was performed in 6 hospitals selected from high incidence of AOPP in Shandong Province. RESULTS: 422 patients of AOPP in 6 hospitals in observation period were treated and observed by the norms of treatment. Among them, the proportion of oral poisoning was 97.16%, middle and severe degree were 87.44%. Compared with themselves 2 years ago before standard treatment, the curative effect of the norms of treatment for AOPP was much better than before. The mortality rate of AOPP declined from 9.87% to 1.66% (Chi2 = 27.92, P < 0.01), that was much better than the average therapeutic effect level of all our province in the same period (the mortality rate: 8.92%) (Chi2 = 26.05, P < 0.01). The average amount of atropine [(37.54 +/- 17.76) mg], dropped greatly [(1280.70 +/- 69.22) mg] (U = 439.22, P < 0.01).The usage of atropine by continuous intravenous injection with venous pump was better than ordinary intravenous injection. The mean dosage of pralidoxime chloride increased twice than the previous (U = 19.48, P < 0.01). There was no drug poisoning. CONCLUSION: The standard treatment of AOPP is urgently needed in our country, especially in rural area. By this trial, the satisfactory effect of the norms of treatment for AOPP summarized is observed and it reduces the fatality rate remarkably.


Assuntos
Intoxicação por Organofosfatos , Praguicidas/intoxicação , Intoxicação/terapia , Padrão de Cuidado/normas , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
12.
J Huazhong Univ Sci Technolog Med Sci ; 29(4): 404-8, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19662351

RESUMO

The roles of voltage-dependent K(+) channels during activation and damage in alveolar macrophages (AMs) exposed to different silica particles were examined. Rat AMs were collected by means of bronchoalveolar lavage, and were adjusted to 5 x 10(5)/mL. After AMs were exposed to different concentrations (0, 25, 50, 100, 200 microg/mL) of quartz particles and 100 microg/mL amorphous silica particles for 24 h, the voltage-depended K(+) current in AMs was measured by using patch clamp technique. Meanwhile the leakage of lactate dehydrogenase (LDH) and the viability of AMs were detected respectively. Patch clamp studies demonstrated that AMs possessed outward delayed and inward rectifying K(+) current. Exposure to quartz particles increased the outward delayed K(+) current but it had no effect on inward rectifier K(+) current in AMs. Neither of the two K(+) channels in AMs was affected by amorphous silica particles. Cytotoxicity test showed that both silica particles could damage AM membrane and result in significant leakage of LDH (P<0.05). MTT studies, however, showed that only quartz particles reduced viability of AMs (P<0.05). It is concluded that quartz particles can activate the outward delayed K(+) channel in AMs, which may act as an activating signal in AMs to initiate an inflammatory response during damage and necrosis in AMs induced by exposure to quartz particle. K(+) channels do not contribute to the membrane damage of AMs.


Assuntos
Exposição Ambiental/efeitos adversos , Macrófagos Alveolares/efeitos dos fármacos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/fisiologia , Quartzo/toxicidade , Animais , Líquido da Lavagem Broncoalveolar/citologia , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/patologia , Tamanho da Partícula , Técnicas de Patch-Clamp , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
13.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-301304

RESUMO

nflammatory response during damage and necrosis in AMs induced by exposure to quartz particle. K+ channels do not contribute to the membrane damage of AMs.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...