Biomedical subjects

Jiang Liu

Publications and source records attributed to Jiang Liu.

36 records · Page 2Linked to original sources

PubMed2004

Expression of chicken ovalbumin upstream promoter-transcription factor II enhances invasiveness of human lung carcinoma cells.

Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) plays an essential role in angiogenesis and development. It is differentially expressed in tumor cell lines, but its role in carcinogenesis is largely unknown. We demonstrate here that noninvasive human lung cancer cells become invasive when COUP-TFII was expressed. The expression of extracellular matrix degrading proteinases, such as matrix metalloproteinase 2 and urokinase-type plasminogen activator, was up-regulated in these cells. This finding was confirmed by transduction of different human lung cancer cell lines with COUP-TFII protein and also by using antisense expression. We observed disorganization of actin filaments and focal adhesion kinase phosphorylation in COUP-TFII-transfected human lung cancer cells in addition to the increase in extracellular metalloproteinase activity. These results suggest that COUP-TFII may be considered as a new target for anticancer therapies.

Actins↗

PubMed2004

Ouabain induces endocytosis of plasmalemmal Na/K-ATPase in LLC-PK1 cells by a clathrin-dependent mechanism.

BACKGROUND: We have demonstrated that ouabain causes dose- and time-dependent decreases in (86)Rb uptake in porcine proximal tubular (LLC-PK1) cells. The present study addresses the molecular mechanisms involved in this process. METHODS: Studies were performed with cultured LLC-PK1 and Src family kinase deficient (SYF) cells. RESULTS: We found that 50 nmol/L ouabain applied to the basal, but not apical, aspect for 12 hours caused decreases in the plasmalemmal Na/K-ATPase. This loss of plasmalemmal Na/K-ATPase reverses completely within 12 to 24 hours after removal of ouabain. Ouabain also increased the Na/K-ATPase content in both early and late endosomes, activated phosphatidylinositol 3-kinase (PI(3)K), and also caused a translocation of some Na/K-ATPase to the nucleus. Immunofluorescence demonstrated that the Na/K-ATPase colocalized with clathrin both before and after exposure to ouabain, and immunoprecipitation experiments confirmed that ouabain stimulated interactions among the Na/K-ATPase, adaptor protein-2 (AP-2), and clathrin. Potassium (K) depletion, chlorpromazine, or PI(3)K inhibition all significantly attenuated this ouabain-induced endocytosis. Inhibition of the ouabain-activated signaling process through Src by 4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2) significantly attenuated ouabain-induced endocytosis. Moreover, experiments performed in SYF cells demonstrated that ouabain induced increases in the endocytosis of the Na/K-ATPase when Src was reconstituted (SYF+), but not in the Src-deficient (SYF-) cells. CONCLUSION: These data demonstrate that ouabain stimulates a clathrin-dependent endocytosis pathway that translocates the Na/K-ATPase to intracellular compartments, thus suggesting a potential role of endocytosis in ouabain-induced signal transduction as well as proximal tubule sodium handling.

Adaptor Protein Complex 2↗

PubMed2004

[Expression of transforming growth factor-beta1 in renal fibrosis of human mesengial proliferative glomerulonephritis].

OBJECTIVE: To explore the possible effect of transforming growth factor-beta(1) (TGF -beta(1)) on the development of renal fibrosis in human mesengial proliferative glomerulonephritis (MsPGN). METHODS: Immunohistochemistry method, sirius red staining polarization microscopy and the computer imaging analysis system were used to detect the expression of TGF-beta(1), the distribution of collagen I, collagen III and collagen IV. RESULT: In MsPGN with renal fibrosis, collagen IV was increased markedly,and collagen I and collagen III appeared in the expanded mesengial matrix abnormally. Collagen III and collagen IV were increased markedly in tubulointerstitium. TGF-beta(1) expression was positively correlated with the expression of collagen I, collagen III and collagen IV in tubulointerstitium (r=0.82 0.92,P<0.01), and negatively correlated with I/III, I/IV and III/IV (r=-0.83,-0.92, P<0.001). CONCLUSION: Abnormal increase of TGF-beta(1) may be one of the important factors associated with glomerular sclerosis and tubulointerstitial fibrosis through the increment and abnormal distribution of collagen I, collagen III and collagen IV.

Collagen↗

PubMed2003

Role of caveolae in signal-transducing function of cardiac Na+/K+-ATPase.

Ouabain binding to Na(+)/K(+)-ATPase activates Src/epidermal growth factor receptor (EGFR) to initiate multiple signal pathways that regulate growth. In cardiac myocytes and the intact heart, the early ouabain-induced pathways that cause rapid activations of ERK1/2 also regulate intracellular Ca(2+) concentration ([Ca(2+)](i)) and contractility. The goal of this study was to explore the role of caveolae in these early signaling events. Subunits of Na(+)/K(+)-ATPase were detected by immunoblot analysis in caveolae isolated from cardiac myocytes, cardiac ventricles, kidney cell lines, and kidney outer medulla by established detergent-free procedures. Isolated rat cardiac caveolae contained Src, EGFR, ERK1/2, and 20-30% of cellular contents of alpha(1)- and alpha(2)-isoforms of Na(+)/K(+)-ATPase, along with nearly all of cellular caveolin-3. Immunofluorescence microscopy of adult cardiac myocytes showed the presence of caveolin-3 and alpha-isoforms in peripheral sarcolemma and T tubules and suggested their partial colocalization. Exposure of contracting isolated rat hearts to a positive inotropic dose of ouabain and analysis of isolated cardiac caveolae showed that ouabain caused 1) no change in total caveolar ERK1/2, but a two- to threefold increase in caveolar phosphorylated/activated ERK1/2; 2) no change in caveolar alpha(1)-isoform and caveolin-3; and 3) 50-60% increases in caveolar Src and alpha(2)-isoform. These findings, in conjunction with previous observations, show that components of the pathways that link Na(+)/K(+)-ATPase to ERK1/2 and [Ca(2+)](i) are organized within cardiac caveolae microdomains. They also suggest that ouabain-induced recruitments of Src and alpha(2)-isoform to caveolae are involved in the manifestation of the positive inotropic effect of ouabain.

Animals↗

PubMed2003

Light emitting diode irradiation protect against the amyloid beta 25-35 induced apoptosis of PC12 cell in vitro.

BACKGROUND AND OBJECTIVES: Whether light emitting diode (LED) irradiation has effects on "beta-amyloid (A beta) induced apoptosis," a leading hypothesis of the cause of Alzheimer's disease (AD), or not? STUDY DESIGN/MATERIALS AND METHODS: Monolayer cell cultures of PC12 were subjected to A beta or/and LED irradiation at various intensity. Cell apoptosis was confirmed by morphological criteria, DNA fragmentation assay, and FAScan flow cytometer assay. RESULTS: Treatment of the cells with LED irradiation significantly diminished A beta induced apoptosis within 24 hours. CONCLUSIONS: The LED irradiation, when utilized at power of 0.9 W/m(2) and 60 minutes has significantly diminished A beta induced apoptosis of PC12 cells.

Amyloid beta-Peptides↗

PubMed2003

Early combined treatment with carboplatin and the MMP inhibitor, prinomastat, prolongs survival and reduces systemic metastasis in an aggressive orthotopic lung cancer model.

We studied the synthetic matrix metalloproteinase inhibitor (MMPI) prinomastat (AG3340) in a well-established NCI-H460 orthotopic lung cancer model that exhibits highly predictable regional and systemic metastatic patterns. Both primary and metastatic tumors express the matrix metalloproteinases (MMP-2), MT1-MMP (MMP-14) and tissue inhibitor of metalloproteinases (TIMP-2). The anti-tumor activity of prinomastat was investigated both as a single agent and in combination therapy with carboplatin. Treatment with both carboplatin (at two dose levels) and prinomastat commenced when the primary lung cancer was approximately 200-300 mg in size and without gross or microscopic evidence of metastases. As single agents, prinomastat significantly reduced the incidence of kidney metastasis, but had no effect on metastatic frequency to other organs. As single agents neither drug enhanced length of survival over control animals, although microvessel counts in prinomastat-treated tumors were lower than in tumors from control animals (P<0.01). In combination prinomastat and the lower dose of carboplatin significantly enhanced survival over control animals, and over animals treated with carboplatin alone (P<0.05). Tolerance to this combination was assessed with body weight and serum biochemistries. At the higher carboplatin dose, toxicity became evident both as a single agent and in combination with prinomastat. Our results suggest that the administration of prinomastat in combination with standard cytotoxic chemotherapy during early stages of tumor growth and metastasis may prolong survival in non-small cell lung cancer (NSCLC) patients.

Animals↗

PubMed2003

Effect of green tea extract on cardiac hypertrophy following 5/6 nephrectomy in the rat.

BACKGROUND: Left ventricular hypertrophy commonly complicates chronic renal failure. We have observed that at least one pathway of left ventricular hypertrophy appears to involve signaling through reactive oxygen species (ROS). Green tea is a substance that appears to have substantial antioxidant activity, yet is safe and is currently widely used. We, therefore, studied whether green tea supplementation could attenuate the development of left ventricular hypertrophy in an animal model of chronic renal failure. METHODS: Male Sprague-Dawley rats were subjected to sham or remnant kidney surgery and given green tea extract (0.1% and 0.25%) or plain drinking water for the next 4 weeks. Heart weight, body weight, and cardiac Na-K-ATPase activity were measured at the end of this period. To further test our hypothesis, we performed studies in cardiac myocytes isolated from adult male Sprague-Dawley rats. We measured the generation of ROS using the oxidant sensitive dye dichlorofluorescein (DCF) as well as (3H)phenylalanine incorporation following exposure to cardiac glycosides with and without green tea extract. RESULTS: Administration of green tea extract at 0.25% resulted in attenuation of left ventricular hypertrophy, hypertension, and preserved cardiac Na-K-ATPase activity in rats subjected to remnant kidney surgery (all P < 0.01). In subsequent studies performed in isolated cardiac myocytes, both ouabain and marinobufagenin (MBG) were both found to increase ROS production and (3H)phenylalanine incorporation at concentrations substantially below their inhibitor concentration (IC) 50 for the sodium pump. Addition of green tea extract prevented increases in ROS production as well as (3H)phenylalanine incorporation in these isolated cardiac myocytes. CONCLUSION: Green tea extract appears to block the development of cardiac hypertrophy in experimental renal failure. Some of this effect may be related to the attenuation of hypertension, but a direct effect on cardiac myocyte ROS production and growth was also identified. Clinical studies of green tea extract in chronic renal failure patients may be warranted.

Animals↗

PubMed2003

Endocytosis and signal transduction: basic science update.

Endocytosis can be separated into the categories of phagocytosis and pinocytosis. Phagocytosis can be distinguished from pinocytosis primarily by the size of particle ingested and by its dependence on actin polymerization as a key step in particle ingestion. Several specific forms of pinocytosis have been identified that can be distinguished based on their dependence on clathrin or caveolin. Both clathrin- and caveolin-dependent pinocytosis appear to require the participation of dynamin to internalize the plasma membrane. Other, less well-characterized forms of pinocytosis have also been described. Although endocytosis has long been known to affect receptor density, recent studies have demonstrated that endocytosis through clathrin- and caveolin-dependent processes plays a key role in receptor-mediated signal transduction. In some cases, blockade of these processes attenuates, or even prevents, signal transduction from taking place. This information, coupled with a better understanding of endocytosis mechanisms, will help advance the field of cell biology as well as present new targets for drug development and disease treatment.

Actins↗

PubMed2003

Phospholipase C and phosphatidylinositol 3-kinase signaling are involved in the exogenous arachidonic acid-stimulated respiratory burst in human neutrophils.

To define the role of phospholipase C (PLC) and phosphatidylinositol 3-kinase (PI-3K), signaling pathways in arachidonic acid (AA)-stimulated respiratory burst in human neutrophils, the AA-stimulated respiratory burst, Ins(1,4,5)P(3) production, PI-3K activation, and cytoplasmic Ca(2+) mobilization were investigated. It was found that Ins(1,4,5)P(3) production and PI-3K activity in AA-stimulated cells were increased in a dose-dependent manner. U73122, the PLC inhibitor, effectively inhibited the AA-stimulated respiratory burst and Ca(2+) release from the intracellular calcium store but not the activity of PI-3K, indicating the independence of PI-3K signaling on PLC activation. Wortmannin, the PI-3K inhibitor, at the concentration sufficient to inhibit PI-3K activity, can only partially inhibit Ca(2+) release from the internal store, indicating a partial regulation of PLC signaling by PI-3K and the existence of two pathways initiated by different PLC subfamilies. One is regulated by PI-3K activation, and the other is independent of PI-3K signaling. It was observed that AA could still induce a noncapacitative Ca(2+) entry in the cells when Ca(2+) release from the intracellular store was blocked by a PLC inhibitor, or a capacitative Ca(2+) entry was induced by preincubation with thapsigargin. However, the AA-mediated, noncapacitative Ca(2+) entry seems to play a little, if any, role in the stimulated respiratory burst. The present study suggests that the PLC signaling pathway, which may be activated by PLC(beta) and PLC(gamma), respectively, and the PI-3K signaling pathway are involved in the AA-stimulated respiratory burst in human neutrophil.

Androstadienes↗

PubMed2003

Involvement of mitogen-activated protein kinases and reactive oxygen species in the inotropic action of ouabain on cardiac myocytes. A potential role for mitochondrial K(ATP) channels.

Binding of ouabain to Na+/K+-ATPase activated multiple signal transduction pathways including stimulation of Src, Ras, p42/44 MAPKs and production of reactive oxygen species (ROS) in rat cardiac myocytes. Inhibition of either Src or Ras ablated ouabain-induced increase in both [Ca2+]i and contractility. While PD98059 abolished the effects of ouabain on [Ca2+]i it only caused a partial inhibition of ouabain-induced increases in contractility. On the other hand, pre-incubation of myocytes with N-acetyl cysteine (NAC) reduced the effects of ouabain on contractility, but not [Ca2+]i. Furthermore, 5-hydroxydecanoate (5-HD) blocked ouabain-induced ROS production and partially inhibited ouabain-induced increases in contractility in cardiac myocytes. Pre-incubation of myocytes with both 5-HD and PD98059 completely blocked ouabain's effect on contractility. Finally, we found that opening of mitochondrial K(ATP) channel by diazoxide increased intracellular ROS and significantly raised contractility in cardiac myocytes. These new findings indicate that ouabain regulates cardiac contractility via both [Ca2+]i and ROS. While activation of MAPKs leads to increases in [Ca2+]i, opening of mitochondrial K(ATP) channel relays the ouabain signal to increased ROS production in cardiac myocytes.

Animals↗

PubMed2002

Prognostic significance of thymomas in patients with myasthenia gravis.

BACKGROUND: The presence of thymoma may be a negative prognostic factor with respect to the outcome of myasthenia gravis (MG). METHODS: Of 122 consecutive patients with MG undergoing thymectomy between August 1994 and September 2000, 37 had a thymoma. Postoperative radiation was administered to all patients with stage II thymoma and higher. To determine differences in presentation and outcome, thymoma patients were compared with patients with atrophic (n = 49) or hyperplastic (n = 36) thymus gland on final pathology. RESULTS: Thymoma patients were significantly older (52 +/- 14 vs 36 +/- 15 years, p < 0.0001) and included a significantly higher proportion of males (54% vs 28%, p = 0.006) than patients without thymoma. However, the preoperative Osserman grade and the duration of symptoms before surgery were not significantly different between groups. Mean follow-up after thymectomy was not significantly different between patients with or without thymoma (32 +/- 23 vs 37 +/- 19 months, respectively, p = 0.3). At last follow-up, the proportion of asymptomatic patients (63% vs 70%, respectively, p = 0.5) and the mean Osserman grade (0.6 +/- 0.9 vs 0.5 +/- 0.9, respectively, p = 0.6) were similar in both groups. In addition, the rate of complete remission reached 36% at 5 years in patients with or without thymoma (p = 0.8). CONCLUSIONS: Although myasthenic patients with thymoma are significantly older and include a greater proportion of males, the overall outcome, including the rate of complete remission, was similar between patients with or without thymoma. Therefore, the presence of a thymoma should not necessarily be viewed as a negative prognostic factor regarding recovery from myasthenia gravis.

Adult↗

PubMed2002

Animal models for studying lung cancer and evaluating novel intervention strategies.

The pathogenesis of lung cancer progression, invasion and metastasis remains undefined. Clinically relevant laboratory models of the disease could greatly facilitate its clarification. Model systems of lung cancer that accurately reflect different biologic properties and disease stages are necessary to ensure proper experimental design of studies aimed at increasing our understanding of the disease. Such models are also essential tools to accelerate development of new therapies for lung cancer. In this review we summarize the available lung cancer model systems in use today and define both their utility and limitations.

Animals↗

PubMed2002

Effects of cardiac glycosides on sodium pump expression and function in LLC-PK1 and MDCK cells.

BACKGROUND: The decreases in proximal tubule sodium reabsorption seen with chronic renal failure and volume expansion have been ascribed to circulating digitalis-like substances (DLS). However, the circulating concentrations of DLS do not acutely inhibit the sodium pump to a degree consistent with the observed changes in proximal tubule sodium reabsorption. METHODS: We examined how cell lines that simulated proximal (LLC-PK1) and distal tubule (MDCK) cells responded to acute (30 min) and long-term (up to 12 hours) Na+,K+-ATPase inhibition with DLS. RESULTS: In LLC-PK1, but not MDCK cells, low concentrations of ouabain decreased 86Rb uptake profoundly in a time and dose dependent manner. In LLC-PK1 cells grown to confluence, transcellular 22Na flux was markedly reduced in concert with the decreases in 86Rb uptake. Similar findings were observed with marinobufagenin (MBG) and deproteinated extract of serum derived from patients with chronic renal failure. However, inhibition of the Na+,K+-ATPase with low extracellular potassium concentrations did not produce any of these effects. Western and Northern blots detected no change in alpha1 Na+,K+-ATPase protein and message RNA, respectively, in LLC-PK1 cells treated with ouabain for 12 hours. However, the decrease in enzymatic activity of Na+,K+-ATPase of these cells was comparable to observed decreases in 86Rb uptake. Differential centrifugation as well as biotinylation experiments demonstrated a shift of the Na+,K+-ATPase from the plasmalemma with prolonged ouabain treatment. CONCLUSIONS: The results show that binding of cardiac glycosides by proximal (but not distal) tubular cells results in internalization of Na+,K+-ATPase with the net effect to amplify inhibition of the Na+,K+-ATPase. As the circulating concentrations of DLS increase with chronic renal failure and volume expansion, we suggest that this phenomenon explains some of the decreased sodium reabsorption by the proximal tubule seen in these conditions.

Animals↗

PubMed2002

[Enhancement of antigen presenting function of dendritic cells by IL-2 gene modification and its mechanism].

OBJECTIVE: To investigate the effects of IL-2 gene modification enhancement of the antigen-presenting function of the mouse bone marrow derived dendritic cells and on the activation of CTL induced by MHC class I molecule restricted antigen peptides as well as the related immunological mechanisms. METHODS: DCs were prepared from mouse bone marrow and modified by recombinant IL-2 adenovirus (DC-IL-2). The IL-12 and IFN-gamma levels in culture supernatant of DC and CTL were examined by ELISA, the expression of costimulatory molecules and fluorescent intensity of endocytosis of OVA-FITC in DC by FACS, the capacity of presenting 3LL cell tumor antigen by (3)H-TdR incorporation method, the MHC class I-restricted tumor-antigen-peptide Mut1 of 3LL cells pulsed DC-IL-2 to induce CTL cytotoxicity by (51)Cr 4-hr releasing assay. RESULTS: After IL-2 gene modification, DC-IL-2 could produce high level of IL-12 [(78.4 +/- 6.6) pg.(1 x 10(6) cells)(-1).ml(-1)]. The expression of costimulatory molecules on DC-IL-2 was increased, the fluorescent intensity of DC captured OVA-FITC was enhanced, and the proliferation of allo-T cells from 3LL bearing mouse pulsed with Mut1 was also enhanced. Mut1 antigen peptide pulsed DC-IL-2 could induce more potent antigen-specific CTL cytotoxicity and excrete high concentration of IFN-gamma [(1 168 +/- 58.4) pg/ml] in vivo. CONCLUSION: IL-2 gene modification of DC can activate second signal for DC presenting antigen, and enhance the function for capturing and presenting tumor antigen. DC-IL-2 pulsed with MHC class I restricted tumor-antigen-peptide can induce specific anti-tumor immune response more effectively. Owing to IL-2 gene modification, the functions of IL-12 excretion and T cell activation of DC were promoted, so that the capacity of CTL excreting IFN-gamma was enhanced, which are relevant to the immune mechanism.

Adenoviridae↗

PubMed2002

[Study on intervention and comparison of rational use of antibiotics on perioperative period of clean incision and clean-defiled incision].

OBJECTIVE: To explore a set of scientific evaluation and intervention methods on perioperatur period which fits for China's situation, and to promote the development of rational drug use. METHODS: Two would tertiary general hospitals were selected and separated in to intervention group and control group. Intervention was carried out and compared at the same period on inpatient surgical cases of thryroidectomy, mastectomy, cholescystectomy, and hysteromyomectomy plus appendix. RESULTS: The average drug costs was decreased from 1 601.27 yuan to 1 489.59 yuan and the average antibiotics use from 740.20 yuan to 352.03 yuan (P < 0.01) in the intervention group pre and post intervention. There was a remarkable improvement on the rationality of antibiotics use in intervention group, from 31.35% to 91.81% (P < 0.01) pre and post intervention, implemented in the hospital. CONCLUSION: It is practicable and effective to implement rational drug use where intervention was carried out, since it plays an active role on promoting safely, effectively and economic antibiotic use in China.

Anti-Bacterial Agents↗

PubMed2002

[Hazards of radio frequency magnetic field and their prevention and control].

The paper briefs the sources of radio frequency (RF) electromagnetic field, their hazards to human health and the hygienic standards of RF electro-magnetic field for occupational exposure and for general population exposure. Based on the physical properties of RF electromagnetic field, the author put forward the comprehensive measures for controlling the electromagnetic radiation to meet the hygienic standards. These measures are improvement of the technology to lower the intensity of RF electromagnetic radiation, shielding the RF radiation sources to reduce the radio frequency levels in accessible areas, increasing the distance between the sources and human, and using personal RF protecting devices in area of high radio frequency levels, etc.. In protecting the general population from exposing to RF radiation, measures keeping a safe distance between the sources and the public play very important role, in which good city planning and the effective control of new and existing RF sources are very important. Referring to the RF electromagnetic problems by using electrical devices in the household, different measures based on the above principles for controlling RF hazards are also cited.

Cataract↗

PubMed2002

Experience of minimally invasive treatment in 520 patients with intracranial aneurysms.

OBJECTIVE: To summarize the experience of minimally invasive treatment in 520 patients with intracranial aneurysms on a retrospective study. METHODS: The measures used in the treatment of 520 patients were reviewed in terms of timing of surgery, induced-hypotensive anesthesia, brain protection combined with temporal occlusion of the feeding artery, external drainage of CSF, dynamic monitoring of intracranial pressure, blood flow velocity, serum osmolality and CT scanning, anti-vasospasm therapy as well as selected interventional endovascular embolization of aneurysms. RESULTS: Of the 520 patients, 485 were treated with either direct clipping or endovascular embolization and 35 patients were treated non-surgically. In 449 patients undergoing direct clipping and 36 undergoing endovascular embolization, intraoperative rupture of aneurysm occurred in 27 (6.0%) and 0%, respectively. Death occurred in 13 (2.6%), hemiplegia in 8 (1.6%), and vegetative state in 2 (0.4%). The operative mortality of direct clipping was 3.8% in 210 patients before 1990 and 1.8% in 275 patients after 1990 (36 patients undergoing endovascular embolization, the operative mortality was 0%). CONCLUSION: The outcome of patients with intacranial aneurysms can be markedly improved and the operative mortality can be lowered by minimally invasive treatment.

Adult↗

PubMed2002

[Appropriate dust control measures for jade carving operations].

OBJECTIVE: To provide the appropriate dust control measures for jade carving operations. METHODS: Dust concentrations in the workplace were measured according to GB/T 5748-85. Ventilation system of dust control were measured according to GB/T 16157-1996. Dust particle size distributions for different sources and particle size fraction collecting efficiencies of the dust collectors were measured with WY-1 in-stack 7 stage cascade impactors. RESULTS: On the basis of adopting wet process in the carving operations, local exhaust ventilation system for dust control was installed, which included: the special designed slot exhaust hoods with hood face velocity of 2.5 m/s and exhaust volume of 600 m3/h. The pipe sizes were determined according to the air volume passing through the pipe and the reasonable air velocities. Impinging scrubber or bag filter dust collector were selected to treat the dust laden air from the local exhaust ventilation system, which gave a total collecting efficiency of 97% for impinging scrubber and 98% for bag filter; The type of fan and its size were selected according to the total air volume of the ventilation system and maximum total pressure needed for the longest pipe line plus the pressure drop of the dust collector. CONCLUSIONS: Practical application showed that, after installation and use of the appropriate dust control measures, the dust concentrations in the workplaces could meet or nearly meet the national hygienic standard and the dust laden air at the local exhaust ventilation system could meet the national emission standard.

Dust↗