Biomedical subjects

Fan Lü

Publications and source records attributed to Fan Lü.

15 recordsLinked to original sources

PubMed2006

Enzymatic hydrolysis of polysaccharide-rich particulate organic waste.

Hydrolysis of organic particulates in rapid fermentative processes can be inhibited. The volatile fatty acids (VFA) released during fermentation reduce pH. Whether VFA or the drop in pH inhibits hydrolysis is unclear. The effects of pH and acetate on the enzymatic hydrolysis of a potato sample that contains both carbohydrate and protein were studied at fixed pH (5-9) in the presence/absence of 20 g/L of acetate. Experimental results showed that the effects of pH and acetate on the hydrolysis of carbohydrate differed from those on the hydrolysis of protein. Numerous kinetic models fitted the hydrolysis data obtained during the first 40 h of hydrolysis when inhibitory effects were insignificant. The Chen-Hashimoto model was used herein to fit the hydrolysis data obtained during 144 h of reaction. Also, the non-competitive inhibition model of three inhibitors (H(+), OH(-), total/undissociated/dissociated acetate) successfully described the inhibition of the hydrolysis of both carbohydrate and protein.

Acetates↗

PubMed2006

[Effect of pH value on fermentation pathways of biodegradable organic waste].

Batch reactors were set up to evaluate the effect of pH value on the anaerobic fermentation of biodegradable organic waste. The results show that pH=7 of fermentative media is favorable for the microbial growth and proliferation, thereby promoting hydrolysis and acidogenesis of particulate biodegradable organic waste. The predominant fermentation types are diverse at different pH value, butyric acid fermentation dominates at pH=7, and at the later phase of pH= 8, propionic acid fermentation dominates at the later phase of pH=5. Lactic acid is produced at the early phase of fermentation, but gradually degrades at pH=5 and pH=7, while remains constant at pH=8. The predominant metabolic pathway shifts from alcohol-forming pathway to acid-forming pathway except for pH=5, where alcoholic fermentation still dominates at the later phase. The first-order hydrolysis constants k(h) for pH 5, 7 and 8 are equal to 0.000 8 h(-1), 0.000 9 h(-1) and 0.0002 h(-1), respectively. The soluble total organic carbon is mainly composed of acidogenic products after 100 h, 300 h and 600 h for pH=7, 5 and 8, respectively.

Acetic Acid↗

PubMed2006

Partial least square modeling of hydrolysis: analyzing the impacts of pH and acetate.

pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, batch experiments were conducted at fixed pH value (pH 5-9) with or without acetate (20 g/L). The hydrolysis efficiencies of carbohydrate and protein were evaluated by carbon and nitrogen content of solids, amylase activity and proteinase activity. The trend of carbohydrate hydrolysis with pH was not affected by the addition of acetate, following the sequence of pH 7>pH 8>pH 9>pH 6>pH 5; but the inhibition of acetate (20 g/L) was obvious by 10%-60 %. The evolution of residual nitrogen showed that the effect of pH on protein hydrolysis was minor, while the acetate was seriously inhibitory especially at alkali condition by 45%-100 %. The relationship between the factors (pH and acetate) and the response variables was evaluated by partial least square modeling (PLS). The PLS analysis demonstrated that the hydrolysis of carbohydrate was both affected by pH and acetate, with pH the more important factor. Therefore, the inhibition by acetate on carbohydrate hydrolysis was mainly due to the corresponding decline of pH, but the presence of acetate species, while the acetate species was the absolutely important factor for the hydrolysis of protein.

Acetates↗

PubMed2006

[Vision quality of intraocular refraction surgery].

Intraocular refractive surgery is one of challenges since it is undertaken mostly for high myopia patient with healthy transparent crystalline lens. The improved vision quality is the premise for conducting this kind of surgery. Vision quality is one of comprehensive factors which are connected to the surgery techniques, ocular optics, ocular physical biometry, intraocular lens power calculation and psycho-physical perception of patient.

Humans↗

PubMed2006

[The relationship between corneal astigmatism with a vector-based method and whole eye second order wavefront aberrations].

OBJECTIVE: To investigate the relationship between corneal astigmatism and second order wavefront aberration in myopic eyes. METHODS: The corneal astigmatism and the whole eye wavefront aberrations of both eyes of 246 subjects were measured using the Humphrey corneal topography and the WASCA wavefront analyzer. According to axial of the corneal astigmatism, the subjects were divided into five groups (WR(0), WR(180), AR, OA(45) and OA(135)). The corneal astigmatism was decomposed into J(45) and J(0) with a Vector-based method, and correlated with the 2nd order Zernike aberrations (C(3) and C(5)). RESULTS: The mean corneal astigmatisms for the five groups were -1.34 D x 6.87 degrees, -1.03 D x 23.15 degrees, -0.48 D x 89.55 degrees, -0.91 D x 156.87 degrees and -1.02 D x 176.74 degrees respectively. Most of the corneal J(45) and J(0) components were correlated significantly with the C(3) and the C(5) aberrations in the whole eye. While the correlation coefficients (R(2)) between the J(45) and the C(3) were 0.138, 0.119, 0.090, 0.526 and 0.501, the R(2) between the J(0) and the C(5) were 0.711, 0.736, 0.864, 0.866 and 0.785 for the five groups respectively. CONCLUSIONS: The corneal astigmatism plays an important role in determining the 2nd order wavefront aberration in the whole eye, and the combination processes between the corneal and internal astigmatism (compensation and/or addition) change with the axial of the corneal astigmatism.

Adolescent↗

PubMed2005

Epidemiologic study on human immunodeficiency virus infection among children in a former paid plasma donating community in China.

BACKGROUND: Illegal plasma collecting activities in mid 1990s caused a large number of human immunodeficiency virus (HIV) infections in rural areas of central-eastern China. Although most of these activities have been stopped, there were few reports on secondary transmission from infected former plasma donors to their spouses and from infected mothers to their children. This study was to determine the extent of HIV infections among young children in a rural community with a large proportion of plasma donors. METHODS: A survey was conducted among children aged under 7 years in a former plasma donating community in September 2000: finger blood was collected for HIV antibody testing. Another survey was repeated among children aged under 8 years and their families in the same community in April 2001: urine samples were collected for HIV testing. HIV positive children and samples of HIV negative children, whose mothers were positive based on 2001 survey, were followed up until September 2002 to investigate HIV seroconversion, disease progression and HIV strain analysis. Questionnaires were administered to collect information on children's delivery, breast feeding, medical history and their parents' commercial blood donation history and HIV status. RESULTS: Among 169 children surveyed in 2000, 10 (5.9%) were HIV positive. Of 224 children, 11 were positive in 2001. The overall prevalence rate in the two surveys was 5.0% (17/337) when counting 56 repeated children only once. Of children born to HIV positive mothers, 28.9% were infected. A seroconversion rate of 2.5 per 100 child-years was observed by following up 28 HIV negative children. No statistically significant associations were found between children's HIV infection and their histories of blood transfusion, surgery, immunization injection or medical injections. All infections were HIV-1 subtype B' strain, the average dispersion rate is 7.4%. DNA sequence analysis showed a close relationship between the seroconverted children and their infected mothers. CONCLUSIONS: HIV vertical transmissions in the rural former plasma donating community was significant. Intervention measures should be taken to prevent further transmission. It was estimated that the HIV spread in this community occurred in 1994 or even earlier. Many infected people are developing AIDS now: treatment and care are urgently needed for these sick people.

Blood Donors↗

PubMed2005

[Expression of bFGF receptor and TGF-beta receptors in cultured human scleral fibroblasts].

OBJECTIVE: To examine the expression of basic fibroblast growth factor receptor (FGF R1) and transforming growth factor-beta receptors (TGF-beta RI and TGF-beta RII) in cultured human scleral fibroblasts. METHODS: Scleral fibroblasts of passages 2-4 were used for the present studies. Polyclonal antibodies against FGF R1, TGF-beta RI and TGF-beta RII were used to detect the proteins of these receptors. Indirect immunofluorescence staining method (IIF) was used. RESULTS: Antibodies for FGF R1, TGF-beta RI and TGF-beta RII produced specific staining of the entire cell surface, including the cell membrane enveloping cytoplasmic projections; positive staining in some cells was most intensive in the perinuclear region. Immunostaining mainly originated from the cell membranes, indicating that the presence of the receptor proteins on the cell surface. The intensity of staining for TGF-beta RI and TGF-beta RII was relatively strong, while staining of FGF R1 was relatively weak. The cells treated with PBS instead of primary antibodies did not produce specific staining. CONCLUSION: This study shows that cultured human scleral fibroblasts express the receptor protein for FGF R1, TGF-beta RI and TGF-beta RII and also indicates that these growth factors may influence these cells. Exogenous bFGF and TGF-beta administration may elicit actions through the binding with these receptors in the scleral fibroblasts.

Cells, Cultured↗

PubMed2005

[Focus on safety and efficiency of refractive surgery].

Based on the strong trend of refractive surgery development, the conception of this surgery on the healthy eye should be set up. It is suggested to focus on the study of safety and efficiency. The base of safety and efficiency is indicated to be the pre-surgery scientific measurement and prediction system.

Humans↗

PubMed2005

[A retrospective cohort study on the natural history of human immunodeficiency virus among formal plasma donors in central China].

OBJECTIVE: To study the time span from human immunodeficiency virus (HIV) infection to full bloom AIDS and to death. METHODS: Among formal plasma donors (FPD) from 2 counties in central China, 178 HIV cases were confirmed by western blot method but received no ARV treatment under a retrospective cohort study. Data on personal information, history on plasma donation, as well as dates regarding HIV diagnostic confirmation, onset of AIDS and death was collected through reviewing laboratory and medical records thus the course of disease for each case was identified. Incubation and survival time were calculated, using Kaplan-Meier method. RESULTS: The incubation period was 8.31 years on average (95% CI: 8.04 - 8.58 years). The cumulative incidence rate of AIDS was 6.41/100 person-years after HIV infection. The survival time was 9.90 (95% CI: 8.20 - 11.60) months after the onset of AIDS. CONCLUSION: According to the findings from this study, the average incubation was shorter than 9.5 years which was reported by UNAIDS. Comparing with figures that had been reported by UNAIDS, AIDS incidence rate among this population was lower within 6 years but higher since the 7th year on after being infected but the survival time was shorter.

Acquired Immunodeficiency Syndrome↗

PubMed2005

[Expression of muscarinic acetylcholine receptor-1 in human scleral fibroblasts].

OBJECTIVE: The aim of this study was to identify the presence of muscarinic acetylcholine receptors-1 (mAChRs-1) in human sclera in order to determine whether the sclera is a potential site of action for mAChR antagonists. METHODS: Cell lines of human scleral fibroblasts were cultured in Dulbecco Modified Eagle's Medium. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used to detect mRNA expression of M1 receptors in the fibroblasts. Immunocytochemistry was used to detect proteins of mAChRs in the cell lines. Immunohistochemical study was used to further detect the presence of M1 receptor in the frozen scleral sections. RESULTS: The cultured fibroblasts demonstrated mRNA expression of M1 receptor in RT-PCR. Protein of the M1 was present in the fibroblasts by examination of immunocytochemistry and immunohistochemistry staining. CONCLUSION: This study demonstrated the presence of M1 receptor in human scleral fibroblasts at both mRNA and protein levels. This finding indicates that the sclera is a potential site of action for the currently used mAChR antagonists in prevention of human myopia.

Cell Line↗

PubMed2004

A DNA vaccine against extracellular domains 1-3 of flk-1 and its immune preventive and therapeutic effects against H22 tumor cell in vivo.

AIM: To construct a DNA vaccine against extracellular domains 1-3 of fetal liver kinase-1 (flk-1), and to investigate its preventive and therapeutic effect against H22 cell in vivo. METHODS: Flk-1 DNA vaccine was produced by cloning extracellular domains 1-3 of flk-1 and by inserting the cloned gene into pcDNA3.1 (+). Fifteen mice were divided into 3 groups and inoculated by vaccine, plasmid and saline respectively to detect specific T lymphocyte response. Thirty Mice were equally divided into preventive group and therapeutic group. Preventive group was further divided into V, P, and S subgroups, namely immunized by vaccine, pcDNA3.1 (+) and saline, respectively, and attacked by H22 cell. Therapeutical group was divided into 3 subgroups of V, P and S, and attacked by H22, then treated with vaccine, pcDNA3.1 (+) and saline, respectively. The tumor size, tumor weight, mice survival time and tumor latency period were compared within these groups. Furthermore, intratumoral microvessel density (MVD) was assessed by immunohistochemistry. RESULTS: DNA vaccine pcDNA3.1 (+) flk-1-domains 1-3 was successfully constructed and could raise specific CTL activity. In the preventive group and therapeutic group, tumor latency period and survival time were significantly longer in vaccine subgroup than that in P and S subgroups (P<0.05); the tumor size, weight and MVD were significantly less in vaccine subgroup than that in P and S subgroups (P<0.05). The survival time of therapeutic vaccine subgroup was significantly shorter than that of preventive vaccine subgroup (P<0.05); the tumor size, and MVD of therapeutic vaccine subgroup were significantly greater than that of preventive vaccine subgroup (P<0.05). CONCLUSION: DNA vaccine against flk-1 domains 1-3 can stimulate potent specific CTL activity; and has distinctive prophylactic effect on tumor H22; and also can inhibit the tumor growth in vivo. This vaccine may be used as an adjuvant therapy because it is less effective on detectable tumor.

Animals↗

PubMed2004

[A study on difference of ocular motor parameters in myopia].

OBJECTIVE: This study sought to assess the difference of these ocular motor parameters in myopia onset and development were explored. METHODS: 31 emmetropia and 46 myopia adult subjects were included in this study. The myopia subjects were divided into three groups as mild myopia, moderate myopia and high myopia. Phoria at distance and near, positive and negative relative accommodation (NRA/PRA) were measured. Accommodative convergence and accommodation stimulus ratio (AC/A) was determined through phoria values' calculation. RESULTS: Calculated AC/A of myopia was higher than that of emmetropia, and there were trends of elevated AC/A with myopia power increasing. There was significant difference in phoria in near between the myopia group and emmetropia group, but none in that of distance. There was no significant difference in NRA. However, PRA of myopia was lower than that of the emmetropia (P <0.05). CONCLUSIONS: Ocular motor parameters are different in myopia eyes. AC/A is one of key parameters among them, and AC/A is increased in myopia, which indicates out of focus of retinal image in the developing myopia.

Accommodation, Ocular↗

PubMed2003

Direct intratumoral embolization of hypervascular tumors of the head and neck.

OBJECTIVE: To evaluate a devascularization technique for hypervascular tumors of the head and neck by direct intratumoral puncture. METHODS: Six cases of hypervascular tumor of the head and neck were reviewed, focusing on findings from digital subtraction angiography and preoperative direct intratumoral embolization and their effects after the operation. RESULTS: Total devascularization by complete embolization was achieved in 2 cases: 1 nasopharyngeal angiofibroma and 1 spongiform tumor, both of which were completely excised endoscopically with blood loss of 60 ml. Incomplete devascularization through 80% - 90% embolization was achieved in the other 4 cases: 1 paraganglioma was totally removed with 800 ml of blood loss, 1 hemangioblastoma was not completely excised with 400 ml of blood loss and 2 nasopharyngeal angiofibromas involving the intracranial region were partially eliminated with a total blood loss of 1600 ml. CONCLUSION: The new technique of preoperative embolization of hypervascular tumors of the head and neck by direct intratumoral puncture, which can decrease blood loss during the accompanying tumor resection and increase the possibility of complete tumor removal, is feasible, convenient, safe, and effective.

Adolescent↗

PubMed2003

[Study of corrected visual performance and vision quality].

OBJECTIVE: The present study was designed to examine the visual acuity (VA) and contrast sensitivity function (CSF) under three refractive correction methods, the visual performance and vision quality under different correction methods were compared and analyzed. METHODS: Twenty three college students with myopia (41 eyes, myopia range: -1.25 D approximately 9.25 D; astigmatism < 0.50 D) were enrolled and fully corrected by three different methods: 1) spectacles with resin lens material (SP); 2) soft contact lens (SCL); 3) rigid gas-permeable lens (RGP). The distant and near LogMar VA and CSF were examined. To avoid the subjective bias, the correction procedure was randomly selected and the VA chart and CSF chart used had the same pattern but different letters' organization or directions. RESULTS: The best corrected distant VA was significantly higher in RGP wearing eyes than those in the Soft-CL and SP wearing eyes (P < 0.01 and P < 0.05, respectively). No statistically significant difference was detected between the SP and SCL wearing eyes. There was no significant difference in the near VA among these three conditions, although the near VA in RGP group was slightly better than that in the SCL condition. There was no significant difference in CSF value at low spatial frequencies (1.5 cpd and 3 cpd) among these three conditions. However, at middle and high spatial frequencies (6 cpd, 12 cpd and 18 cpd), the RGP curve was the highest and followed by the SCL and SP curves. CONCLUSION: RGP correction offers the best visual acuity quality for myopia subjects. The CSF assessment can be used as an indirect method to evaluate the quality of corrected retinal image.

Adult↗

PubMed2003

[The visual outcome and related factors in cataract patients with extreme myopia].

OBJECTIVE: A prospective study was performed to analyze the visual outcome and factors related to the visual outcome in cataract patients with extreme myopia, in order to provide a principle for intraocular lens (IOL) diopter chosen. METHODS: 43 cases were included in the present series (myopia over 10.00 D, axial length over 27.00 mm, with clear cornea and slight or moderate opacity of the lens). Distance and near visual acuity (NVA), best corrected visual acuity and the fundus were examined before and after the phacoemulsification and implantation of IOL. chi(2) test and stepwise regression analysis were used to identify the predictive factors. RESULTS: (1) Distance visual acuity, NVA and best corrected visual acuity were markedly improved in most cases. (2) NVA and fundus pathologic changes were two important factors for predicting post-operative visual acuity. (3) The prognosis was better in cases with NVA better than 20/200, and in cases with axial length below 29.00 mm. (4) Some cases with postoperative NVA worse than 20/80 complained of difficulty in reading. CONCLUSIONS: NVA is an important factor influencing the outcome of vision and is an important parameter for predicting the outcome of vision in cataract patients with extreme myopia. IOL diopter should be determined carefully by preoperative NVA and the patients' demand for near work.

Adult↗