Biomedical subjects

Zhenlin Liu

Publications and source records attributed to Zhenlin Liu.

6 recordsLinked to original sources

PubMed2006

Multiple-functional capsule catalysts: a tailor-made confined reaction environment for the direct synthesis of middle isoparaffins from syngas.

A capsule catalyst for isoparaffin synthesis based on Fischer-Tropsch reaction was designed by coating a H-ZSM-5 membrane onto the surface of the pre-shaped Co/SiO(2) pellet. Morphological and chemical analysis showed that the capsule catalyst had a core-shell structure. A compact, integral shell of H-ZSM-5 crystallized firmly on the Co/SiO(2) substrate without crack. Syngas passed through the zeolite membrane to reach the Co/SiO(2) catalyst to be converted, and all hydrocarbons formed with straight chain structure must enter the zeolite channels to undergo hydrocracking as well as isomerization in this tailor-made confined reaction environment. A narrow, anti-Anderson-Schultz-Flory law product distribution was observed on these capsule catalysts. Contrary to a mechanical mixture of H-ZSM-5 and Co/SiO(2), C(10+) hydrocarbons were suppressed completely on this novel capsule catalyst, and the selectivity of middle isoparaffins was considerably improved. The carbon number distribution of the products depended on the thickness of the zeolite membrane, and it was possible to selectively synthesize specified distillates, such as gasoline-range, or heavier hydrocarbons from syngas directly, by simply adjusting the thickness of the zeolite membrane of the capsule catalyst. This kind of capsule catalysts can be extended to various consecutive reaction systems as the shell and core components are independent catalysts for different reactions. At the same time, shape selectivity and space-confined effects can be expected for the reactant, intermediates and product of the sequential reactions.

Journal Article↗

PubMed2004

Environmental mycological study and respiratory disease investigation in tussah silk processing workers.

This study presents the results of an investigation of respiratory symptoms, pulmonary function and chest X-ray examinations, and analysis of antibodies to fungi of 197 tussah silk-processing workers and 40 control workers. An industrial hygiene survey and environmental mycological studies were also conducted. The dust concentrations in tussah silk processing workshops were less than 5.1 mg/m(3) on average, with a maximum of 7.8 mg/m(3) below the national health limit of 10 mg/m(3). Most dusts in all tussah silk processing workshops contained less than 1.2% silica. Numbers of isolated fungi in tussah silk processing workshops [755-6,544 cfu/m(3) (colony forming unit/m(3)), were significantly higher than those in control environments (63-472 cfu/m(3)). The prevalences of respiratory symptoms in tussah silk processing workers were higher than those in control workers. The prevalences of respiratory symptoms in exposed male non-smoking workers were 44.4% with chronic cough, and 38.9% with chronic phlegm respectively, which were significantly higher than those (12.5%, 12.5% respectively) in male non-smoking control workers (p<0.05). The prevalences in exposed male smoking workers were 42.9% with dyspnea, and 38.1% with chest tightness respectively, which were significantly higher than those (16.7%, 8.3% respectively) in male smoking control workers (p<0.01). The prevalences of respiratory symptoms in exposed female workers were 25.3% with chronic cough, 38.0% with chronic phlegm, 31.0% with dyspnea, and 29.1% with chest tightness respectively, which were significantly higher than those (10.0%, 10.0%, 10.0%, 5.0% respectively) in female control workers (p<0.01). Fifteen exposed workers often suffered from fever. Five X-rays were abnormal and four cases had nodular or patchy shadows. The prevalences of pulmonary function abnormalities in the exposed female group were significantly higher than those in control groups (p<0.01). The OD(450 nm) values for antibodies to fungi in tussah silk processing workers were significantly higher than those of control workers (p<0.05). The positive rates of anti-fungal antibodies in tussah silk-processing workers were also significantly higher than those of control workers (p<0.01). The results suggested that fungi might be one of the main allergens in respiratory diseases in the tussah silk processing workers.

Adult↗

PubMed2003

Environmental mycological study and respiratory disease investigation in fur-processing workers.

This paper presents the results of an investigation of respiratory symptoms, chest X-ray examinations, and analysis of antibodies to fungi of 138 fur-processing workers and 40 control workers. Industrial hygiene survey and environmental mycological studies were also conducted. The dust concentrations in fur processing workshops (1.8-6.7 mg/m3) were below the national health limit (10 mg/m3). Most dusts in all fur processing workshops contained less than 2.0% silica. Numbers of isolated fungi in fur processing workshops [629-3,681 cfu/m3 (colony forming unit/m3)] were significantly higher than those in control environments (63-503 cfu/m3). The prevalences of respiratory symptoms in fur processing workers were higher than those in control workers, especially among female exposed workers. The prevalences of the symptoms in female exposed workers were 37.9% with chronic cough, 28.4% with chronic phlegm, 10.5% with dyspnea, 22.1% with chest tightness, and 4.2% with fever. Seven cases showed abnormalities in chest X-ray examinations. The OD450nm values for antibodies to fungi in fur processing workers were significantly higher than those in control workers (P<0.05). The prevalences of positive anti-fungi antibodies in fur-processing workers were also significantly higher than those in control workers (p<0.01). The results suggested that fungi might be one of the main allergens in respiratory diseases in fur processing workers.

Adult↗

PubMed2003

Pulmonary function in fur-processing workers: a dose-response relationship.

Pulmonary function tests were conducted in 212 male workers exposed to fur dust in a fur-processing factory, and in 148 unexposed male workers. The authors used the cumulative dose of dust exposure (mg-yr) as an exposure index to relate to pulmonary function injury, as measured by pulmonary function tests, in exposed workers. The results showed that fur workers had lower percentages of predicted pulmonary function, as measured by forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1.0), and maximal flow rate of expiration at 50% and 25% of forced vital capacity (V50 and V25, respectively), compared with controls (p < 0.01). As the cumulative dose of fur dust exposure increased, average levels of pulmonary function declined significantly (p < 0.01), and pulmonary function abnormalities (i.e., < 80% of predicted FVC and FEV1.0, or < 70% of predicted V50 and V25) increased significantly (p < 0.05). Multiple-regression results identified fur dust exposure as the leading risk factor associated with the decline in pulmonary function in the exposed group. The results demonstrated a dose-response relationship between fur dust exposure and respiratory system injury, as measured by pulmonary function tests in fur-processing workers. On the basis of this dose-response relationship and the use of lifetables, the authors proposed an exposure limit of 4 mg/m3 for fur dust.

Adult↗

PubMed2003

Relationship of jute dust to interstitial fibrosis in rat lung.

The relationship between jute dust and lung interstitial fibrosis was studied by instilling groups of rats, via trachea, with jute dust and comparing the results with those for positive (quartz) and negative (saline) controls. The rats were sacrificed at regular intervals and their lungs and hilar lymph nodes were analyzed for collagen content and morphologic changes. The earliest changes consisted of alveolar edema, increased numbers of intraalveolar macrophages, and marked thickening of the interalveolar septa, with mixed cellular infiltrates. Moderate thickening of the alveolar walls and the zones around the peribronchioles was seen in the test groups at 6 mo. After 12 mo, some fibrosis of the alveoli walls and peribronchiole zones occurred. Interstitial cellular nodules were observed occasionally, composed mainly of dust particles, fibroblasts, reticular fibers, and collagen fibers. The collagen content in the lungs of the jute dust groups was significantly higher than for the saline control group for all test periods. The authors conclude that jute dust may induce lung interstitial fibrosis.

Animals↗

PubMed2002

[Study on occupational respiratory diseases in fur-processing workers].

OBJECTIVE: To study the respiratory system injury in fur processing environment. METHODS: Environmental fungal survey was conducted in the fur processing procedures. Investigation of respiratory symptoms and chest X-ray examination were also carried out in 138 fur processing workers and 40 control workers. At the same time, the serum antibodies to fungi were analyzed by ELISA. RESULTS: Fungal number(629-3,681 cfu/m3) in fur processing procedures was much higher than those in the control environment. Cladosporium and Alternaria were the leading strains of fungi in fur processing procedures. The rates of respiratory symptoms(cough, sputum, chest tightness, dyspnea, and fever) in fur processing workers were higher than those in the control workers. The rates of the symptoms in female workers were 37.9%, 28.4%, 10.5%, 22.1%, 4.2%, respectively. Abnormalities of chest X ray were found in 7 workers. The serum antibodies to Cladosporium and Alternaria(A450 nm 0.631, 0.724, respectively) in fur workers were significantly higher than those in the control workers(P < 0.05). The positive rates of the antibodies to Cladosporium and Alternaria(44.2%, 42.8%) were significantly higher than those in the control workers(P < 0.01). CONCLUSION: Cladosporium and Alternaria may be the pathogens of occupational respiratory diseases in fur processing workers.

Alternaria↗