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Liang Li

Publications and source records attributed to Liang Li.

At least 37 records · Page 2Linked to original sources
PubMed2006

The ideal free distribution of clonal plant's ramets among patches in a heterogeneous environment.

The plastic response of clonal plant to different patch quality is not always the same and the degree is different too. So the result of this kind of foraging behaviour is different. In order to make clear whether the ramtes stay in favourable patches and get the quantitative relationship between the ramets distribution among patches and the available resource amount in heterogeneous environment, we develop a theoretical work under ideal free distribution (IFD) theory framework by neglecting some morphological plasticity of the spacer in this article. The results of our general model show that the ramet distribution should obey input matching rule at equilibrium. That means the ratio of ramet number in different patches should be equal to the ratio of available resource amount in these patches. We also use the simulation to predict the distribution pattern under history mattering. The results show that the initial ramets number has significant influence on the final distribution: over matching and under matching both can occur. More initial ramets in favourable patch result in over matching and more initial ramets in unfavourable patch result in under matching. The degree of the deviation from input matching rule is great when the difference of patches is small. These results prove that ideal free distribution theory works the same with animals. The ramets can stay in favourable patches sometimes in spite of the plasticity of the spacer, and the distribution depends on both patch quality and the history factors. But these results are true only when the functional response is type II.

Computer Simulation↗
PubMed2006

Synthesis and biological evaluation of technetium-99m-labeled deoxyglucose derivatives as imaging agents for tumor.

Three deoxyglucose (DG) derivatives, S-DG, MAG(3)-DG and MAMA-BA-DG, were synthesized and labeled successfully with high labeling yields and high radio-chemical purities. Biodistribution in tumor-bearing mice demonstrated that these three new (99m)Tc-deoxyglucose derivatives showed accumulation in tumor and high tumor-to-muscle ratios. Among them, the (99m)Tc-MAG(3)-DG showed the best characteristics as a potential tumor marker for single photon emission computed tomography (SPECT).

Animals↗
PubMed2006

High chemical reactivity of silver nanoparticles toward hydrochloric acid.

High chemical reactivity of Ag nanoparticles was observed in the reaction with hydrochloric acid: Ag (nanoparticles)+ HCl-->AgCl + H2; the reaction product silver chloride was characterized by X-ray powder diffraction to give a direct evidence for the reaction which has been proved impossible for the bulk Ag.

Journal Article↗
PubMed2006

The role of 111indium-octreotide brain scintigraphy in the diagnosis of cranial, dural-based meningiomas.

OBJECTIVE: Meningiomas are common brain tumors with somatostatin receptors that bind octreotide. We report the use of (111)indium-octreotide brain scintigraphy (OBS) for the non-invasive differentiation of meningiomas from other cranial dural-based pathology. METHODS: A retrospective analysis of our experience with OBS for non-invasive identification of meningiomas was performed. Two neuroradiologists, blinded to clinical data, utilized a standardized grading scheme to define the uptake of octreotide at 6 and 24 h post-administration. The correlation between (18) F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), magnetic resonance imaging (MRI) scans, and octreotide uptake was assessed. RESULTS: The cohort consisted of 50 patients having a mean age of 62.4 years and a median follow-up time of 24 months. Management consisted of biopsy (n = 4); resection (n = 10); observation (n = 16); radiosurgery (n = 21); and external beam radiotherapy (n = 3). OBS was correlated with MRI (n = 50); FDG-PET brain studies (n = 38); histology (n = 14), and angiography (n = 1). In cases where definitive diagnosis could be made, the sensitivity, specificity, positive and negative predictor values for OBS alone were 100; 50; 75; and 100, respectively. OBS provided false positive data in 3 patients (metastasis, chronic inflammation, lymphoma). Use of OBS with MRI to differentiate meningiomas from other lesions was highly significant (P < 0.001). FDG-PET correctly identified malignant pathology with 100% sensitivity and specificity. CONCLUSION: OBS may increase the diagnostic specificity of conventional MRI when differentiating meningioma from other dural-based pathologies, while the addition of FDG-PET differentiates benign from malignant lesions.

Adult↗
PubMed2006

Hollow nanoshell of layered double hydroxide.

Hollow nanoshells of layered double hydroxide (LDH) have been fabricated using exfoliated LDH nanosheets as a shell building block and polystyrene beads as a sacrificial template.

Hydroxides↗
PubMed2006

Total synthesis of (+/-)-paeonilide.

The total synthesis of paeonilide, a natural anti-PAF (platelet-activating factor) new skeleton monoterpenoid with an IC(50) value of 8 microg/mL, was achieved in 16 steps with 15% overall yield from commercially available 2-hydroxy-4-methylacetophenone. [reaction: see text]

Acetophenones↗
PubMed2006

Microwave-assisted aqueous synthesis: a rapid approach to prepare highly luminescent ZnSe(S) alloyed quantum dots.

In this paper, we present a new procedure for the rapid synthesis of luminescent ZnSe nanocrystals in aqueous phase by microwave irradiation with controllable temperature. The effects of microwave irradiation and experimental conditions on the synthesis of nanocrystals were investigated systematically. It was found that there were significant effects of pH value of reaction solutions, molar ratio of precursors, and heating time of microwave irradiation on the optical properties of the ZnSe nanocrystals. A series of nanocrystals with different size was prepared in 1 h, and the photoluminescence quantum yield reached up to 17% at the optimal reaction condition. The results of HRTEM and XRD showed that the as-prepared nanocrystals had high crystallinity. The characterizations of EDS spectra and elemental analysis showed that the sulfur content of nanocrystals increased with the growth of nanocrystals. We speculated that the structure of nanocrystals was an alloy ZnSe(S) shell on the surface of the ZnSe particles core. Furthermore, we found that the oxygen from air in the reaction vessel played an important role in the decomposition of the thiol group under microwave irradiation.

Journal Article↗
PubMed2006

Increased risk associated with combined carotid endarterectomy and coronary artery bypass graft surgery: a propensity-matched comparison with isolated coronary artery bypass graft surgery.

OBJECTIVE: Risk associated with combined carotid endarterectomy and coronary artery bypass graft surgery (CEA/CABG) is controversial. The present study objective was to compare morbidity and mortality outcomes in well-matched patients who underwent combined CEA/CABG surgery with patients undergoing isolated CABG surgery with and without a history of a prior CEA. DESIGN: This investigation was designed as a retrospective case-controlled study using data from the Cardiothoracic Anesthesia Patient Registry in a single tertiary institution. The patient population consisted of 1,698 isolated CABG surgery patients with carotid artery stenosis >40%, 708 patients who underwent an isolated CABG surgery but had a history of a prior CEA, and 272 combined CEA/CABG surgery patients who underwent surgery from January 4, 1993, through June 30, 2003. Propensity modeling techniques were used to calculate a propensity score for each patient. Greedy matching resulted in 272 propensity-matched pairs of combined CEA/CABG and isolated CABG patients (primary analysis) and 241 propensity-matched pairs of combined CEA/CABG surgery and isolated CABG surgery with previous CEA patients (secondary analysis). A Fisher exact, chi-square, Wilcoxon rank sum, and Student t test were applied appropriately to compare the propensity-matched pairs. RESULTS: The distribution of covariates among the propensity-matched combined CEA/CABG and isolated CABG groups were similar. Among the propensity-matched pairs in the primary analysis, overall morbidity and mortality were higher in the combined CEA/CABG group compared with the CABG group alone (overall morbidity 15% v 8.8%, p = 0.025, and mortality 5.2% v 1.1%, p = 0.007, respectively). Median intensive care unit (ICU) length of stay was longer (47 v 31 hours, p = 0.004) and hospital length of stay was longer (12 v 9 days, p < 0.001) for the combined CEA/CABG surgery compared with isolated CABG surgery, respectively. Postoperative cardiac, neurologic, serious infection, and renal morbid events were similar between the 2 groups. In the secondary analysis, the rates of mortality, overall morbidity, and neurologic morbidity were similar between the groups, whereas the median ICU and hospital length of stay were significantly longer in the combined CEA/CABG group (47.6 v 39.8 hours, p = 0.025, and 12.0 v 9.0 days, p < 0.001, respectively). CONCLUSIONS: Increased mortality and overall morbidity outcomes were found in the combined CEA/CABG group when compared with well-matched isolated CABG patients, but similar when compared with well-matched isolated CABG patients with a history of previous CEA. Patients undergoing combined CEA/CABG procedures had significantly longer ICU and hospital lengths of stay compared with patients undergoing isolated CABG procedures.

Aged↗
PubMed2006

Three-layer matrix/sample preparation method for MALDI MS analysis of low nanomolar protein samples.

A robust and sensitive sample preparation method is presented for matrix-assisted laser desorption ionization (MALDI) mass spectrometric analysis of low nanomolar concentrations of proteins containing high amounts of common salts and buffers. This method involves the production of densely packed sub-micrometer matrix crystals by depositing a matrix solution on top of a matrix seed-layer prepared on a MALDI target. A sub-microliter aliquot of analyte solution is then directly added to the top of the matrix crystals to form a thin-layer. alpha-Cyano-4-hydroxycinnamic acid (4-HCCA) is used as matrix and demonstrated to give better performance than other commonly used matrices, such as 2,5-dihydroxybenzoic acid (DHB), 2-(4-hydroxy-phenylazo) benzoic acid (HABA), or sinapinic acid. This three-layer method is shown to be superior to the other MALDI sample preparation methods, particularly for handling low nanomolar protein solutions containing salts and buffers.

Animals↗
PubMed2006

An impulse-driven liquid-droplet deposition interface for combining LC with MALDI MS and MS/MS.

A simple and robust impulse-driven droplet deposition system was developed for off-line liquid chromatography matrix-assisted laser desorption ionization mass spectrometry (LC-MALDI MS). The system uses a solenoid operated with a pulsed voltage power supply to generate impulses that dislodge the hanging droplets from the LC outlet directly to a MALDI plate via a momentum transfer process. There is no contact between the LC outlet and the collection surface. The system is compatible with solvents of varying polarity and viscosity, and accommodates the use of hydrophobic and hydrophilic MALDI matrices. MALDI spots are produced on-line with the separation, and do not require further processing before MS analysis. It is shown that high quality MALDI spectra from 5 fmol of pyro-Glu-fibrinopeptide deposition after LC separation could be obtained using the device, indicating that there was no sample loss in the interface. To demonstrate the analytical performance of the system as a proteome analysis tool, a range of BSA digest concentrations covering about 3 orders of magnitude, from 5 fmol to 1 pmol, were analyzed by LC-MALDI quadrupole time-of-flight MS, yielding 6 and 57% amino acid sequence coverage, respectively. In addition, a complex protein mixture of an E. coli cell extract was tryptically digested and analyzed by LC-MALDI MS, resulting in the detection of a total of 409 unique peptides from 100 fractions of 15-s intervals.

Chromatography, Liquid↗
PubMed2006

Highly efficient size separation of CdTe quantum dots by capillary gel electrophoresis using polymer solution as sieving medium.

In this paper, we present a new method for highly efficient size separation of water-soluble CdTe quantum dots (QDs) based on CGE using polymer solution as sieving medium. CdTe QDs were synthesized in aqueous phase by a chemical route with mercaptopropionic acid as a ligand. In the alkaline solution, CdTe QDs possess negative charges and migrate to the anode in the electric field. In linear polyacrylamide sieving medium, the migration time of CdTe QDs was increased with the size of CdTe QDs. The effects of some factors, such as types, concentrations, and pH of sieving media, on the separation of CdTe QDs were investigated systematically. Highly efficient separation of CdTe QDs was obtained in linear polyacrylamide sieving medium, and collection of fractions was automatically accomplished by CGE technique. Our preliminary results show that CGE technique is an efficient tool for characterization and size-dependent separation of water-soluble nanoparticles. In addition, the fraction collection in CGE may be useful in certain special applications such as fabrication of nanodevices in the future.

Acrylic Resins↗
PubMed2006

Conversion of a Bi nanowire array to an array of Bi-Bi2O3 core-shell nanowires and Bi2O3 nanotubes.

A template-based heat-treatment method has been developed to convert metal nanowire arrays into arrays of metal-metal oxide core-shell nanowires and single-crystalline metal oxide nanotubes. This process is demonstrated by kinetically controlling the conversion of single-crystalline Bi nanowires to Bi-Bi(2)O(3) core-shell nanowires via a multistep, slow oxidation method, and then controlling their further conversion to a single-crystalline Bi(2)O(3) nanotube array via fast oxidation. This process can conveniently be extended to fabricate a free-standing, easily oxidized metal-metal oxide nanowire and metal oxide nanotube array, which may have future applications in nanoscale optics, electronics, and magnetics.

Bismuth↗
PubMed2006

Persistent effect of red cell transfusion on health-related quality of life after cardiac surgery.

BACKGROUND: Although red blood cell transfusion has been associated with an increase in early morbid outcomes and reduced long-term survival after cardiac surgery, its relationship to functional quality of life after surgery has not been previously explored. Our objective was to investigate the relationship between perioperative red blood cell and component transfusion and functional health-related quality of life 6 to 12 months after cardiac surgery. METHODS: Of 12,536 patients undergoing cardiac surgical procedures between May 1995 and January 1999, 7,321 completed a self-administered Duke Activity Status Index (DASI) survey preoperatively and least one follow-up survey at nominally 6 or 12 months postoperatively. The influence of baseline DASI, preoperative risk factors, clinical status, laboratory values, operative events, and postoperative morbidities on follow-up DASI were examined with ordinal regression modeling. RESULTS: After adjustment for preoperative DASI, demographic, cardiac and noncardiac comorbidity, type of surgery, postoperative complications, and interval between follow-up DASI, during which patients continued to improve (p < 0.0001), postoperative functional status after cardiac surgery was incrementally worse the more perioperative red cells (p < 0.0001) and platelets (p = 0.02) that had been transfused. CONCLUSIONS: Red blood cell and platelet transfusion have an unintended persistently negative risk-adjusted effect on health-related quality of life after cardiac surgery that extends well beyond initial hospitalization. Reductions in functional recovery paralleled increasing units of red blood cells transfused.

Activities of Daily Living↗
PubMed2006

Transfusion in coronary artery bypass grafting is associated with reduced long-term survival.

BACKGROUND: Perioperative red blood cell (PRBC) transfusion has been associated with early risk for morbid outcomes, but risk related to long-term survival has not been thoroughly explored. Therefore, we examined the influence of PRBC transfusion and component therapy on long-term survival after isolated coronary artery bypass grafting after controlling for the effect of demographics, comorbidities, operative factors, and the early hazard for death. METHODS: The US Social Security Death Index was used to ascertain survival status for 10,289 patients who underwent isolated coronary artery bypass grafting from January 1, 1995 through June 28, 2002. The outcome measure was all-cause mortality during the follow-up period. Unadjusted survival estimates were performed using the Kaplan-Meier techniques. Survival curves for transfusion status were compared with the log-rank test. The parametric decomposition model was used for risk-adjusted survival. A balancing score was calculated for each patient and forced into the final model. RESULTS: Survival among transfused patients was significantly reduced as compared with nontransfused patients. The instantaneous risk of death displayed a biphasic pattern: a declining hazard phase from the time of the operation (early hazard) up until 6 months postoperatively and then a late hazard that continued out until about 10 years. Transfusion of red cells was associated with a risk-adjusted reduction in survival for both the early (0.34 +/- 0.02, p < 0.0001) and late phases (0.074 +/- 0.016, p < 0.0001). CONCLUSIONS: Perioperative PRBC transfusion is associated with adverse long-term sequela in isolated CABG. Attention should be directed toward blood conservation methods and a more judicious use of PRBC.

Age Factors↗
PubMed2006

Red cell transfusion is associated with an increased risk for postoperative atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a common complication after cardiac surgery and is associated with increased resource utilization. Recent evidence supports a role of inflammation in the development of AF. It is also known that red blood cell transfusion modulates inflammation by increasing plasma levels of inflammatory markers. Therefore, we tested the hypothesis that red blood cell transfusion increases the risk of postoperative AF for patients undergoing cardiac surgery. METHODS: Between February 2002 and January 2005, 5,841 patients underwent isolated coronary artery bypass grafting with or without valve replacement. Patient and procedural variables associated with development of new-onset AF were identified by logistic regression. Propensity score matching was used to confirm results. RESULTS: In addition to older age, prior history of AF, higher preoperative hematocrit, beta-blocker withdrawal, longer aortic clamp time, valve surgery, and intensive care unit inotropic usage, intensive care unit red blood cell transfusion increased risk for AF (odds ratio per unit transfused, 1.18; 95% confidence limits, 1.14, 1.23; p < 0.0001). For the 1,360 propensity-matched pairs, intensive care unit red blood cell transfusion was associated with a significant increase in new-onset AF (620 [46%] versus 522 [38%]; p < 0.001). CONCLUSIONS: Intensive care unit red blood cell transfusion is associated with increased occurrence of postoperative AF after cardiac surgery. This factor should be considered in identifying patients who might benefit from prophylaxis to prevent this common postoperative complication.

Aged↗
PubMed2006

Treatment of lesions involving both the infratemporal fossa and middle skull base.

BACKGROUND: Communicating occupying lesions of the intratemporal fossa and mid-cranial fossa represent challenges for neurosurgeons and maxillofacial surgeons. Lesions of the skull base, with complex anatomy, are extremely varied in their histopathology. They often spread via normal anatomic pathways or bony destruction to involve adjacent structures, especially in the case of malignant neoplasms. However, with the development of operative skills and reconstruction techniques, total or near total resection of many such lesions can be accomplished with a low morbidity rate. METHODS: The combined frontotemporal-preauricular infratemporal approach, frontotemporal-orbitozygomatic approach, combined frontotemporal and transmandibular approach, transmandibular approach, and transmaxillary approach were used to resect the lesions using microsurgical skills. The plastic reconstruction included reconstruction of the dura defects, osteosynthesis, and obliteration of the operative cavity. RESULTS: Thirty-three patients with communicating lesions invading both the infratemporal fossa and the middle skull base underwent microsurgery. Among them, lesions were totally resected in 23, subtotally resected in 6, and partially resected in 4. In 29 patients, clinical status improved significantly. Complications were encountered in 7 cases, and morbidity was not remarkable. CONCLUSION: The surgical approach should be selected depending on the size, location, histopathology, and invading extension of the lesion, which can provide excellent visualization and allow for an aggressive and safe resection of lesions involving this region. Familiarity with skull base anatomy, careful microsurgical manipulation, protection of vital structures, reliable plastic reconstruction, intraoperative nerve monitoring, as well as consideration of functional and esthetic outcomes, will all contribute to successful surgery and satisfactory results.

Adolescent↗