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Biomedical subjects

J B Li

Publications and source records attributed to J B Li.

At least 19 recordsLinked to original sources
PubMed2006

Enterobacter bacteremia: Clinical features, risk factors for multiresistance and mortality in a Chinese University Hospital.

BACKGROUND: This study was performed to characterize the clinical features and to identify the risk factors for multiresistance and mortality in patients with Enterobacter bacteremia. PATIENTS AND METHODS: A number of 126 patients with Enterobacter bacteremia in 1995-2004 at the Medical university-affiliated Hospital of Anhui, China were retrospectively analyzed. RESULTS: Of the 126 cases of bacteremia, 81 (64.3%) patients were identified as nosocomial infection. The overall multiresistance rate was 45.2% (57/126). Multiresistance was associated with nosocomial infection, recent invasive procedure, previous third-generation cephalosporins therapy, prolonged perioperative prophylaxis, the species of Enterobacter (E. cloacae) and polymicrobial bacteremia in univariate analysis. In multivariate analysis, previous third-generation cephalosporins therapy (OR = 13.6, p = 0.007) and prolonged perioperative prophylaxis (OR = 6.4, p = 0.029) were the strong, independent risk factors for the multiresistance. The crude 30-day mortality rate was 39.7% (50/126). Mortality directly attributed to Enterobacter spp. was 32.5% (41/126), which was significantly associated with multiresistance, nosocomial infection, recent invasive procedure, and inadequately empirical therapy in univariate analysis. Multivariate analysis revealed that only nosocomial infection (OR = 3.292, p = 0.049) was independently associated with mortality. The survival curve showed that the inappropriate initial therapy group had a lower probability of survival than the appropriate therapy group in infection-related mortality (Log Rank, p = 0.0142). CONCLUSION: Enterobacter is becoming increasingly important nosocomial pathogens. Nosocomial infection is a clinical risk factor tightly associated with multiresistance and worse outcome. More judicious use of third-generation cephalosporins may decrease the incidence of nosocomial multiresistant Enterobacter spp. in China.

Adolescent↗
PubMed2005

A simulation-based interval two-stage stochastic model for agricultural non-point source pollution control through land retirement.

This study presents a simulation-based interval two-stage stochastic programming (SITSP) model for agricultural non-point source (NPS) pollution control through land retirement under uncertain conditions. The modeling framework was established by the development of an interval two-stage stochastic program, with its random parameters being provided by the statistical analysis of the simulation outcomes of a distributed water quality approach. The developed model can deal with the tradeoff between agricultural revenue and "off-site" water quality concern under random effluent discharge for a land retirement scheme through minimizing the expected value of long-term total economic and environmental cost. In addition, the uncertainties presented as interval numbers in the agriculture-water system can be effectively quantified with the interval programming. By subdividing the whole agricultural watershed into different zones, the most pollution-related sensitive cropland can be identified and an optimal land retirement scheme can be obtained through the modeling approach. The developed method was applied to the Swift Current Creek watershed in Canada for soil erosion control through land retirement. The Hydrological Simulation Program-FORTRAN (HSPF) was used to simulate the sediment information for this case study. Obtained results indicate that the total economic and environmental cost of the entire agriculture-water system can be limited within an interval value for the optimal land retirement schemes. Meanwhile, a best and worst land retirement scheme was obtained for the study watershed under various uncertainties.

Agriculture↗
PubMed2005

Elasticity of polymer vesicles by osmotic pressure: an intermediate theory between fluid membranes and solid shells.

The entropy of a polymer confined in a curved surface and the elastic free energy of a membrane consisting of polymers are obtained by scaling analysis. It is found that the elastic free energy of the membrane has the form of the in-plane strain energy plus Helfrich's curvature energy [Z. Naturforsch. C 28, 693 (1973)]. The elastic constants in the free energy are obtained by discussing two simplified models: one is the polymer membrane without in-plane strains and asymmetry between its two sides, which is the counterpart of quantum mechanics in a curved surface [H. Jensen and H. Koppe, Ann. Phys. (N.Y) 63, 586 (1971)]; the other is the planar rubber membrane with homogeneous in-plane strains. The equations to describe equilibrium shape and in-plane strains of the polymer vesicles by osmotic pressure are derived by taking the first-order variation of the total free energy containing the elastic free energy, the surface tension energy, and the term induced by osmotic pressure. The critical pressure above which a spherical polymer vesicle will lose its stability is obtained by taking the second-order variation of the total free energy. It is found that the in-plane mode also plays an important role in the critical pressure because it couples with the out-of-plane mode. Theoretical results reveal that polymer vesicles possess mechanical properties intermediate between those of fluid membranes and solid shells.

Computer Simulation↗
PubMed2003

Dietary methionine requirement of the Chinese egg-laying duck.

1. The dietary methionine requirement of egg-laying ducks was assessed by feeding diets supplemented with graded levels of DL-methionine (0, 4, 8, 12, 16 g/kg dietary protein) for 8 weeks. The basal diet contained 175 g protein and 2.6 g methionine per kg feed (or 14.9 g/kg protein) and an estimated ME of 11.5 MJ/kg. 2. A total of 800 Shaoxin laying ducks (420 d old) were randomly divided into 5 groups of 160 each and fed in 4 separate pens. 3. Dietary supplementation of methionine significantly increased egg production and feed conversion efficiency. 4. Dietary methionine requirement for optimum egg production was estimated to be 25.7 g/kg of dietary protein or 4.5 g/kg of the diet or 380 mg/bird-d. 5. Methionine supplementation increased the methionine level in plasma, and the free glutamic acid and aspartic acid concentrations in plasma were quadratically related to dietary methionine levels. Increasing dietary methionine had little effect on egg quality characteristics.

Amino Acids↗
PubMed2003

A GIS-based modeling system for petroleum waste management. Geographical information system.

With an urgent need for effective management of petroleum-contaminated sites, a GIS-aided simulation (GISSIM) system is presented in this study. The GISSIM contains two components: an advanced 3D numerical model and a geographical information system (GIS), which are integrated within a general framework. The modeling component undertakes simulation for the fate of contaminants in subsurface unsaturated and saturated zones. The GIS component is used in three areas throughout the system development and implementation process: (i) managing spatial and non-spatial databases; (ii) linking inputs, model, and outputs; and (iii) providing an interface between the GISSIM and its users. The developed system is applied to a North American case study. Concentrations of benzene, toluene, and xylenes in groundwater under a petroleum-contaminated site are dynamically simulated. Reasonable outputs have been obtained and presented graphically. They provide quantitative and scientific bases for further assessment of site-contamination impacts and risks, as well as decisions on practical remediation actions.

Decision Support Techniques↗
PubMed2001

Prevalence and analysis of risk factors for infections caused by resistant Escherichia coli strains in Anhui, China.

BACKGROUND: This study analyzes the prevalence of hospital and community-acquired infections caused by Escherichia coli. PATIENTS AND METHODS: The antibiotic resistance pattern was used to characterize the isolates, and a retrospective observational study was performed to assess the relationship between antimicrobial use and bacterial resistance. The study was conducted during a 1-year and 7-month period in a 1,500-bed tertiary care hospital in Anhui, China. RESULTS: An E. coli infection was diagnosed in 1.4% of patients (519/36,179) admitted to the hospital between March 1, 1999 and August 31, 2000. Of the 519 isolates, 489 (94.2%) were resistant to at least one antimicrobial; 86% were resistant to ampicillin, 85% to cephalothin, 83% to piperacillin, 77% to ampicillin/sulbactam, 72% to trimethoprim/sulfamethoxazole (TMP-SMZ), 70% to ciprofloxacin, 61% to cefoperazone, 58% to tobramycin, 56% to gentamicin, 48% to ticarcillin-clavulanate, 44% to cefazolin, 43% to cefuroxime, 36% to cefoxitin, 32% to cefepime, 29% to aztreonam, cefetaxime and ceftriaxone, 28% to ceftazidime, 19% to piperacillin/tazobactam, 10% to amikacin, while all strains tested were susceptible to imipenem. CONCLUSION: Prior receipt of amtimicrobial therapy was significantly associated with infection caused by a resistant organism.

Adolescent↗
PubMed2001

An integrated decision support system for the management of petroleum-contaminated sites.

In this study, a decision-support system was developed for providing environmental managers with an integrated way for concisely analyzing and visualizing the subsurface contamination problem as well as a means for evaluating alternative remediation technologies. It integrated contaminant-transport modeling, risk assessment, and remediation-system design within a general framework. The developed system was applied to a site in western Canada that is contaminated by petroleum products. A three-dimensional multiphase multicomponent model was established, which provided a basis for further risk assessment. Several approaches based on different environmental guidelines were used to analyze risks due to the site contamination. The results suggested the urgency of taking remediation actions. Six remedial alternatives for cleaning up the site were recommended. Decisions could then be made based on a series of analyses and comparisons among the given alternatives.

Conservation of Natural Resources↗
PubMed2001

[Studies on chemical constituents from Dracocephalum moldavica L].

OBJECTIVE: To study the chemical constituents from the whole plant of Dracocephalum moldavica. METHOD: The compounds were isolated using RA polystyrene resin and silica gel column chromatography, and the structures were elucidated by means of spectral method. RESULT: Four compounds were identified as tilianin, agastachoside, acacetin and oleanolic acid. CONCLUSION: All the compounds were isolated from this plant for the first time.

Flavones↗
PubMed2001

[Studies on the chemical constituents from Myristica yunnanensis Y. H. Li].

OBJECTIVE: To study the chemical constituents of Myristica yunnanensis. METHOD: Compounds were isolated using silica gel and reversed-phase C18 column chromatography, their structure were identified by means of spectral method. RESULT: Five known compounds were identified as otobain(I), beta-sitosterol(II), ergosterol(III), afzelin(IV) and quercetrin(V). CONCLUSION: Compounds IV and V were isolated first from Myristica.

Flavonoids↗
PubMed2000

[A further research on physiopathological basis of "Liver Yang Forming Wind Syndrome"].

The multiple experimental parameters of different aspects in this study were determined in the patients with "Liver Yang Forming Wind Syndrome (LYFWS)", "Qi Deficiency Blood Stagnation Syndrome (QDBSS)" and "Yin Deficiency Forming Wind Syndrome (YDFWS)". The results showed that cerebral hemorrhage was similar to cerebral infarction in almost all parameters and the two diseases were with LYFWS. It was found that there were several characteristics in LYFWS, i.e. 1. Hyperfunction of sympathetic adrenal medullary system. 2. Hypotriiodothyroidoglobulin syndrome. 3. The marked changes of the active substance regulating vessel smooth muscle function. 4. The increased inflammatory medicators. The pathophysiological parameters in patients with QDBSS were the same as those with YDFWS, but the changes of QDBSS and YDFWS weRe milder than those of LYFWS.

6-Ketoprostaglandin F1 alpha↗
PubMed2000

[Enantiomeric separation of N-FMOC amino acids with sulfobutyl ether-beta-cyclodextrin as chiral additive by capillary electrokinetic chromatography].

Enantiomeric separation of N-FMOC amino acids by capillary electrophoresis with an anionic chiral resolving agent, sulfobutyl ether-beta-cyclodextrin (SBE-beta-CD) with average substitution degree of 3.8, employed as chiral additive was studied. Chiral separation was achieved with the mode of electrokinetic chromatography due to the electrophoretic mobility and chiral complexing ability of the chiral additive. The effects of pH of background electrolyte, the concentration of sulfobutyl ether-beta-cyclodextrin on enantiomeric separations were investigated. The enantiomeric separations of 8 N-FMOC amino acids were accomplished, among which 5 N-FMOC amino acids could be on baseline separated.

Amino Acids↗
PubMed2000

[Synthesis and application of sulfonated beta-cyclodextrins as chiral additives in capillary electrophoresis].

Three new kinds of the sodium salt of sulfonated beta-cyclodextrins with different degrees of substitution were synthesized and characterized. A simple synthesis method was employed by direct sulfonating reaction with concentrated sulfuric acid. Sulfonated beta-cyclodextrins were used as chiral resolving agents for the capillary electrophoretic separation of enantiomers in high pH and low pH background electrolytes. In different electrophoretic polarity mode, the effects of the type and concentration of sulfonated beta-cyclodextrin were investigated. Sulfonated beta-cyclodextrins were proved to be strong complexing agents for basic and neutral analytes.

Cyclodextrins↗
PubMed1993

Neuroretinal rim area in early glaucoma.

Neuroretinal rim area (NRA) is the only clinical measurement that reflects the real amount of nerve fibers in optic disc. We measured the photographs of the optic disc in 132 eyes of 132 subjects in 6 groups: normal subjects with small cups, normal subjects with large cups, suspected glaucoma with small cups and those with large cups, primary open angle glaucoma (POAG), low tension glaucoma (LTG). The mean NRAs of POAG, LTG and suspected glaucoma with large cups were less than those of normal subjects with large cups. In normal subjects, a high correlation between cup area and disc area was found, while NRA correlated weakly with disc area. Both semiquantitative scores of diffuse and localized retinal nerve fiber layer defects were correlated significantly with NRA. We suggest that measurement of NRA and examination of retinal nerve fiber layer defect could improve the detection of acquired changes of optic disc in early glaucoma.

Adult↗
PubMed1992

[Neuroretinal rim area (NRA) in early glaucoma].

The authors photographically measured the optic disks in 6 groups, namely, normal subjects with small cups and those with large cups, suspected glaucoma with small cups and those with large cups, primary open angle glaucoma (POAG) and low tension glaucoma (LTG). The effect of ocular optical magnification was corrected. The mean NRAs of POAG, LTG and suspected glaucoma with large cups were found less than those of the other 3 groups. In the normal subjects, an evident positive correlation existed between the cup area and the disk area, and the NRA was weakly correlated with the disk area. The diffuse and localized retinal nerve fiber layer defects were negatively correlated with the NRA significantly.

Adult↗
PubMed1992

[Thickness of the media of pulmonary trunk in children with mountain sickness].

Thickness of the media of pulmonary trunks from 58 children with mountain sickness were measured with micrometer. The results showed that the thickness of the media were increased coincidently with the increase of age, and PT/AT ratio. The pattern of the elastic laminae was in accordance with that of the aorta in the same group. The authors consider that these changes in mountain sickness are due to pulmonary hypertension development.

Altitude Sickness↗
PubMed1991

[Studies on the structure of gnetifolin A of Gnetum parvifolium (Warb.) C.Y. Cheng].

A new component, gnetifolin A, was isolated from the ethyl acetate fraction of the stem of Gnetum parvifolium (Warb.) C.Y. Cheng together with three known components isorhapontigenin, resveratrol and beta-sitosterol. The structure of gnetifolin A has been established as 2-(3',5'-dihydroxy-4'-methoxyphenyl)-3-methoxy-5-hydroxybenzofuran by spectroscopic methods (UV, IR, MS, 1HNMR, 13CNMR, 2D-NMR).

Benzofurans↗